After mid-August reprieve, yet another prolonged California heatwave

Filed in Uncategorized by on August 25, 2017 3,560 Comments

A very hot summer thus far away from immediate coast; weak monsoon on western fringe

This summer has been among the hottest–and in some places the hottest–on record in most places, except along the immediate coast. (WRCC)

Summer 2017 has featured a recurring pattern across California, characterized by strong and persistent ridging just inland of the West Coast and prolonged, searing heatwaves across most interior portions of the state (and, indeed, across much of the American West). As has been widely noted, immediate coastal regions (within 10 or so miles of the ocean) have not been nearly as anomalously hot this summer due to the relative lack of the strong offshore winds typically required to bring hot temperatures to California’s characteristically chilly beaches. Nonetheless, warm ocean temperatures especially across the SoCal Bight have kept overall mean (and overnight) temperatures above average nearly everywhere. This combination has resulted in a rather curious situation where the majority of California is experiencing a “top 5” hottest summer on record, yet the majority of Californians (most of whom reside in densely populated coastal regions in the Bay Area and in Los Angeles/Orange counties) have witnessed comparatively mild conditions. Cities like Redding and Bakersfield are on track to approach or exceed all-time records for the greatest number of 100+ degree days in a single year, and it’s possible that other places will follow suit after another 1-2 weeks of prolonged hot weather to come.

While Arizona has seen an extremely active monsoon so far in 2017, most of California has seen much less mountain/desert thunderstorm activity than usual. (WRCC)

Another unusual characteristic of summer 2017 has been the relative absence of mountain/desert convective precipitation associated with the North American Monsoon. Interestingly, there has so far been a very strong east-west differential in monsoonal precipitation–with much of Arizona experiencing near record-wet summer conditions and some spots in the SoCal deserts experiencing near-record dry conditions. Part of the reason for this divergence is likely the persistence of high pressure on the western margin of the monsoon circulation, which has inhibited precipitation over most of California. There are still at least a few weeks left in the canonical monsoon season, and it’s often the case that California experiences a late-season surge in moisture/convective potential. Indeed, there is some indication that this very situation may evolve over the next couple of weeks (see below).

 

Upcoming heatwave will be prolonged, and will extend to coast in SoCal

Unfortunately, this post will read something like a broken record: there is more heat on the way, possibly record-breaking in some spots, and this time it may extend closer to the immediate coastline (especially in Southern California). A strong ridge will once again build directly overhead this weekend, bringing hot weather to nearly the entire state. Weak offshore flow will bring hot temperatures all the way to the beaches in SoCal, and some daily record highs may be threatened. Further north, coastal areas may yet again escape the hottest conditions, but another very prolonged streak of triple digit weather is expected across most of California’s interior valleys.

Current GFS forecast showing well above temperatures across California on three consecutive upcoming weekends. (NCEP via tropicaltidbits.com)

A “second wave” of heat may develop by next weekend, preventing any meaningful cooldown. Current model forecasts suggest this one may be centered further north, and could once again bring record-breaking heat to the Pacific Northwest. If this second wave evolves largely as expected, numerous all-time cumulative “temperature threshold exceedance” records (i.e., most days above 90/100/110 degrees in a single year) may be broken in the Central Valley. At present, there are not really any indications of average or below average temperatures heading well into September (which is actually prime coastal heatwave season in California).

Models have variously suggested over the past few days that a fairly robust monsoonal incursion westward into California–affecting the mountains and deserts, and perhaps also the coastal plain–will eventually develop during the second week of this heatwave. Also in the mix is the potential for some tropical remnants to become entrained in southerly flow aloft–and it’s getting to be the time of year when that sort of pattern becomes more likely. So far this summer, the global models have overestimated the westward extent of monsoonal surges, so at this point we’ll just have to wait and see how this evolves in the 7-10 day period.

 

A California connection to potentially devastating Hurricane Harvey?

A strong, persistent, and anomalous ridge over the Western U.S. will bring major California/PacNW heatwave, and prevent Hurricane Harvey from moving away from Texas. (NCEP via tropicaltidbits.com)

At the time of this writing, rapidly-intensifying Hurricane Harvey was approaching the mid-Texas Gulf Coast. There has been widespread consternation in the meteorological community over the past 48 hours regarding the potentially devastating impacts of this remarkable storm, which likely poses the greatest threat to human lives of any landfalling American storm since Hurricane Katrina. While the storm is currently approaching category 4 status (with sustained winds in excess of 120 mph), these destructive winds (and even the enormous storm surge associated with them) are actually not the primary concern associated with Harvey. Instead, the extremely slow-moving nature of this storm following landfall has the potential to generate truly astonishing rainfall accumulations across the Texas low country. Recent simulations from the ECMWF model, for example, are showing the potential for 50+ inches (over 4 feet!) of rainfall in less than 5 days. Needless to say, rainfall of even half this magnitude could produce widespread and devastating freshwater flooding–and the latest model forecasts would approach the largest rainfall totals ever observed in North America.

Aside from the potential for a weather disaster of national significance, Harvey is also interesting from a California perspective given the importance of the anomalous western ridge in “setting the stage” for a tremendous tropical rainfall event over 1000 miles away. Hurricane Harvey is already moving slowly, but will continue to decelerate and eventually stall over land within 100 miles of the Gulf of Mexico over the weekend–potentially remaining within 150 miles of the Houston area for the next 5-6+ days. This extremely sluggish movement will occur due to the combined influence of the powerful Western ridge (which will prevent westward movement and rapid dissipation over relatively arid West Texas) and the lack a of deep trough over the central U.S. (which will prevent Harvey’s circulation from being “picked up” by a larger passing storm). Thus, as the West Coast bakes amidst yet another prolonged heatwave, parts of the Gulf Coast may simultaneously experience an astonishing–and potentially devastating–tropical deluge. Stay tuned.

Tags: , ,

  • Thirstier Nick (Santa Maria)

    Dew point finally drops to 62 degrees. It’s heading back towards normal.

  • Thunder98 (Santa Maria Valley)

    Dew Points suddenly dropped down to 62F. No wonder it feels more comfortable and less sweating.

    https://uploads.disquscdn.com/images/109d3470d700a90f256fd760b6ae180760bfcc52cb949d814a6fc9feb254be79.png

  • Thunderstorm

    Just a hunch here but action in the Central valley this evening from Sacramento north.

  • Great Winter of 2017 (SMC)

    Dew point peaked at 68 F yesterday and 69 F today and the temp was 83 degrees! This is the most muggy it has ever felt here, anyone else on here in the Bay Area reach high 60s?

    • 66 dp now.

    • AntiochWx

      yes 68 peak, I haven’t experienced this muggy here. I wasn’t here during 2006 when some posters said bay area cracked 70. Wonder if Daniel can round up some graphics with dew point records in the bay.

  • Great Winter of 2017 (SMC)

    https://twitter.com/webberweather/status/905209260132503553 Surface winds of 192 MPH and pressure has dropped 9 MB, I think it could be approaching 195 MPH winds!

    • thebigweasel

      It’ll probably back off a bit during the night hours–and it’s a little after 9pm where the eye is.

    • AntiochWx

      11pm update may up the advisory to 190mph, which would tie Hurricane Allen for strongest winds in Atlantic basin.

  • MetaGhost (Berkeley)
  • MetaGhost (Berkeley)
    • Bombillo1

      Well, that is what disaster looks like, if anyone was wondering…

      • thebigweasel

        That’s the first half. It traverses Florida, losing very little power, and then ramps up again in the Gulf. Anywhere from Huntsville to Brownsville is staring down the barrel of a gun.

    • weathergeek100

      So depressing. Life, property, million dollar homes on the beach, any home! This could be catastrophic.

  • 805 Weather (Camarillo)

    Wow, still deepening… 916mb & winds still at 185mph. If you ask me, this is going to make TS forecaster’s jaws drop if it the winds keep strengthening. https://twitter.com/crankywxguy/status/905218569289523201 https://twitter.com/weatherchannel/status/905218165990449152

  • thebigweasel

    CAZ080>084-061000-
    /O.CON.KMFR.SM.Y.0005.000000T0000Z-170907T1900Z/
    Western Siskiyou County-Central Siskiyou County-
    South Central Siskiyou County-
    North Central and Southeast Siskiyou County-
    Northeast Siskiyou and Northwest Modoc Counties-
    Including the cities of Etna, Fort Jones, Yreka, and Weed
    256 PM PDT Tue Sep 5 2017

    …DENSE SMOKE ADVISORY REMAINS IN EFFECT UNTIL NOON PDT
    THURSDAY…

    * Visibilities: A quarter of a mile or less, at times.

    * Locations in the dense smoke advisory: Mid-elevations and
    valleys of Siskiyou County from the Shasta Valley westward

    * Dense Smoke Impacts: Dense smoke from wildfires will create
    hazardous driving conditions, at times, on area roadways.

    * View the hazard area in detail at
    https://www.wrh.noaa.gov/mfr/HAZARD

    Just to add to the general merriment, much of Northern California is under a Red Flag warning beginning tomorrow. Many dry cells expected to traverse the region.

  • molbiol

    Here is the scale for Tornadoes. Kinda puts things in perspective WRT Irma…

    https://uploads.disquscdn.com/images/18e65bec37b8ead5ef13649426760b29084a4a18c4f863015cb427ef1576444f.jpg

    • alanstorm

      Basically a 60 mile wide F4 tornado with a storm surge.

      • Great Winter of 2017 (SMC)

        *EF5 with them gusts

  • David

    Was 91 degrees here in Paradise at 2:00. Now its 76 degrees with thunder, lightning and pouring rain! First rain since June 11.

  • 805 Weather (Camarillo)
    • Wolfpack

      It seems Florida is going to have a hard time avoiding Irma.

  • AntiochWx
  • rob b-Truckee/East Bay

    As various news agencies hype the possibility of where Irma might land…. i think KTVU might have pulled an all timer neglecting to say “Tampa Bay Area.”
    https://twitter.com/ktvu/status/905233680200634368

    • Oh no!!! I haven’t prepared for Irma yet!!!

    • Admode (Susanville)

      I knew it was going to be big, I didn’t realize it was going to be THAT big!!

  • rob b-Truckee/East Bay

    One more for Charlie did you witness this action today? Did Tobias return in a dust storm?
    https://twitter.com/brennanews4/status/905229457115320321

    • Charlie B

      It was wild. My daughter is on Reno High’s tennis team. In the middle of the match the dust storm hit and visibility went to zero in a matter of seconds. It was basically impossible to see the ball let alone hit it.

  • AntiochWx
  • AntiochWx
    • Thunderstorm

      The all seeing BLUE EYE!!

  • AntiochWx
  • Cap’n

    I won’t be fooled as I know we have a few warm days ahead before winter comes, but it feels like fall arrived this afternoon. Steady soaking rain falling at the moment after off and on showers all afternoon, and tomorrow/Thursday are supposed to have more of the same. I’ve got .3″ in the gauge for the day, good stuff.

    Edit: and more thunder and lightning have just started.

    • AlTahoe

      It feels amazing. Snuck in a quick lap at corral and it was definitely a brown pow day. Thunder storms started up again right as I got back to the truck. Yard is nice and soaked and it is still raining with a temp of 64F

      • Cap’n

        Couldn’t ride today but I’m on it tomorrow and Friday.

    • matthew

      Just got in and I was thinking that – if it was 20 degrees cooler – it felt like a late autumn/early winter storm. We went directly from winter to summer. Maybe we will go straight back from summer to winter?

      • Thunderstorm

        So there is cooler air aloft some how. If it stays cool then there must be a lot of cooler air aloft. Maybe this persistent inversion every where will finally say uncle.

    • inclinejj

      While out walking the pup we spotted some winged termites swarming around. Seems a bit early.

    • Amy Cohen

      You are beckoning the Sierra Storm King and I’m not even close to finishing winter prep! Shush!

      • Cap’n

        I’m always beckoning the Storm King. I know it’s sacrilegious to say but I just don’t like summer much. I’m with you though, not prepared yet at all. Don’t worry, we’ve got more heatwaves coming.

  • CHeden

    Hats off to the HRRR, which had showers moving over Cottonwood this evening.
    At 3 p.m. we were cloudless above and due to smoke, I couldn’t see anything coming in. By 5 p.m. we were mostly cloudy and now we’ve just finished with a really nice T’storm that pushed west off off of Lassen….right on schedule. Temps are now 81F, a wonderful departure from the oppressiveness of the last two weeks.

    • Thunderstorm

      If you want to know whats coming your way the next 3 days (emphasis on 3 here) then read the forecast from the NWS in Medford Oregon. There usually very accurate. Enjoy the read.

  • SlashTurn (Santa Barbara)
  • celo

    NOAA lately has really had a hard time forecasting temperatures more than 48 hours out. Yesterday, it had 90s for Santa Barbara and now it is low 80s. I don’t know if the models can handle the subtropical influences that well.

  • AntiochWx

    ECMWF enso forecast. Most of their spread is near neutral conditions. https://uploads.disquscdn.com/images/3fb90e7055eeb5ad96eaf5b43ff6a2bf739ec802269f24b228401521477cd6c1.png

  • Tuolumne

    Something I never see mentioned but which seems like it could be important, is that the winds of a hurricane aren’t just wind. They also contain a *lot* of rain. Water is heavy (~100x the density of air) and moving water is very powerful. I wonder how much the damage potential of a hurricane’s winds is increased by the water content of those winds?

    • Thunderstorm

      Would imagine that anything moving at 150MPH would do damage.

  • RandomTreeInSB

    For anyone who’s interested, Here’s a link to a weather station on Barbuda, which is set to get a direct hit from hurricane Irma.
    http://www.wrh.noaa.gov/mesowest/getobext.php?wfo=pqr&sid=BARA9&num=12&raw=0

    • Great Winter of 2017 (SMC)

      stopped sendings every 6 minute data transmissions at 11:54 PM EST

      • RandomTreeInSB

        I noticed there’s a bit of a delay in the data transmission. Although I wouldn’t be surprised if the station eventually stopped working altogether with a cat-5 approaching it.

    • FolsomPrisonBlues

      At cat 5 i was half expecting to see the felled trees being blown out of the video with the house.

  • AntiochWx

    It will be interesting to see what the Euro shows tonight, if it holds steady, it is going to be another interesting showdown between the GFS and Euro. I will side with the Euro all day long, there is a reason its known as the king to weather trackers.

  • 805 Weather (Camarillo)
  • alanstorm

    In Auburn. HUMID HUMID HUMID.
    Brief rain showers moved NW & now has that smell….
    One of the most humid days I’ve experienced in California, felt like I was in Thailand, sweating like an animal

  • Great Winter of 2017 (SMC)

    http://www.ssd.noaa.gov/PS/TROP/floaters/11L/imagery/rb_lalo-animated.gif @jasonjacksonwillamette:disqus hope your brother is not located in one of those islands in or west of the hurricane, it’s getting battered

    • Jason Jackson Willamette

      GW, My brother Bob, is on St. Thomas, VI. He’s next. Going to be a day to remember, 9/6/17. Pray for him and his wife, Sally.

  • Nate

    Here’s the Météo France radar page from Guadeloupe–Barbuda is entering the eyewall.
    http://www.meteo.fr/temps/domtom/antilles/pack-public/animation/anim_radar_guad_mf_com.html

  • jstrahl

    Felt like yet another warm day in central Berkeley, peaked at 78F between noon and 1:30. Around 3, quite suddenly, low clouds started building near the hills. Around 4, they surged, it was overcast by 4:30.

  • SolarWinds56

    ISS Passes over Irma today. Amazing view of the storm!! https://youtu.be/QBDheVyH8SM

  • RunningSprings6250
    • Is that a tornado?

    • Nathan

      I saw this earlier….seems more like a tornado.

    • Cap’n

      And the bizarre Terminatoresque/digital friz voices made that eerie as hell. Hope the best for those islands, a lot of shantys will be hanging on by every rusty nail they’ve got.

  • molbiol

    From devastating hurricanes to catastrophic wildfires. Reading this article made me feel somewhat queasy:
    http://people.com/human-interest/oregon-wildfire-strands-150-hikers-as-father-recounts-escape/

  • RandomTreeInSB

    Berserk mode activated on Barbuda. https://uploads.disquscdn.com/images/b14bbf62bae870d95183eb3451f94b429cd9fdd440029c8d69cda27874485508.png
    (This data is delayed by 30 minutes. I wonder how high it is now)

  • GR

    Correct me if I’m wrong, anyone, but weren’t there a couple of articles last year noting the comparative scarcity of tropical storms the last decade?

    • Tuolumne

      Just a quick look at the Atlantic Basin: http://www.aoml.noaa.gov/hrd/tcfaq/E11.html

      Named storms 1968-2016: average of 11.8/yr.
      Average for 2007-2016: 14.5/yr.

      Hurricanes 1968-2016: average of 6.2/yr.
      Average for 2007-2016: 6.5

      Looks like it’s within the normal range of variation.

  • Great Winter of 2017 (SMC)

    Have fun tmrw Tahoe crew, those in far interior NorCal and Cheden! Marginal risk! https://uploads.disquscdn.com/images/db53a80cb6c54e8026dc6d4dd528f4556ef7704cb80e52684ec51e7e03021aa5.jpg

  • Thirstier Nick (Santa Maria)

    Really foggy night in Santa Maria. Seeing a notably decrease in temperature, too. Let’s get back to the 50s.

  • Great Winter of 2017 (SMC)
    • Nathan

      If that WX station is still alive, it’s going to be right smack dab in the middle of the eye – going to be amazing to see a total dropoff in wind speed for like 20 minutes.

      edit: ha!

      06 Sep 1:06 am 76 CALM 27.31 27.31 82
      06 Sep 1:00 am 76 NNW 108G155 27.40 27.40 83
      06 Sep 12:54 am 76 NW 118G154 27.53 27.53 83

      • Unbiased Observer

        I just checked and it’s now reporting CALM conditions…crazy!

        • Nathan

          yeah pretty sure “CALM” means literally no wind, and honestly I don’t think the eye is _that_ calm. Wind should be 5-20mph. Pretty sure the station gauge broke!

          • Unbiased Observer

            I agree, it’s still reading CALM

    • Great Winter of 2017 (SMC)

      lol now in eye pressure at 27.31 inches or 925 MB

    • Thunderstorm

      Absolutely awesome, great find there!

    • Thirstier Nick (Santa Maria)

      That’s tremendous.

    • Incredible!

  • Cap’n

    The whole hurricane has disappeared from radar. Am I in the Twilight Zone, or just the most incompetent WWer in the land? Probably the latter but this is still bizarre.

  • Thunderstorm

    Here is a super information site from Jacksonville Florida. I believe this meteorologist is the best they have in Florida. Go to: action newsjax.com/weather/talkin-the-tropics , looking at the page scroll down to a small red box that says new, click on the heading underneath. You will now have access to information not available elsewhere. Well worth the time!!

    • Unbiased Observer

      Links to Edmunds.com

      • Jason Jackson Willamette

        Yep, me too. Pull the link Thunder. It’s a very annoying AD.

        • John

          The link works, but you have to paste to the finishing part in the second paragraph.

  • Great Winter of 2017 (SMC)

    So the bouy below’s anemometer broke I just heard so wind gusts were likely higher, absolutely insane! They need some vantage Vue stations out there, they are tested to 180 mph in wind tunnels!

  • AntiochWx

    And Euro slightly caves to the GFS, tracks on the eastern side of FL.

    • 805 Weather (Camarillo)
      • Sokafriend

        Interesting observation and makes sense. So awe inspiring this new earth.

      • AntiochWx

        Read somewhere that as long as the dynamics of the hurricane is modeled correctly, the initialization of a wrong pressure reading doesn’t drastically affect the path of the modeled hurricane. Don’t know how true that is.

  • 805 Weather (Camarillo)

    For the first time since 8/15, the dew point here has finally dropped below 63°F on my PWS. my max was 74°F… Finally doesn’t feel like the south around here.

  • 82/83 El Nino baby (San Jose)

    Pictures and videos starting to come in. St Martin looks pretty bad and have not seen anything from Barbuda yet. Looks like a big surge occured.

    https://twitter.com/williamsnews24/status/905407312428494848

    https://twitter.com/jottes/status/905425397621424128

    https://twitter.com/ClasePopular/status/905419214768439296

  • thebigweasel
  • Thunder98 (Santa Maria Valley)

    Temps dropped to 60F.

  • thebigweasel

    I was in the eye of a hurricane once, back in 1962, a Cat 2 that passed over Halifax. What I remember, aside from the sudden calm, was innumerable birds flying in circles in the eye, trapped by the storm.

  • Who Killed Kenny Strawn?

    Irma isn’t just a cat 5. She’s a cat 5 +++, The worst case scenario is the entire state of Florida (except for the panhandle) is under total devastation with area of landfall annihilated. It could make Andrew, Harvey, and even Katrina look like child’s play. If the landfall occurs close to Miami, the entire area may be uninhabitable for months. If thing rides up the East Coast of Florida, Kennedy Space Center could fully be destroyed to the point where they salvage the whole thing. Even places far inland as Orlando may make experience cat 2-3 level damage. We are talking about unprecedented territory.

    • Chris

      But it looks like now it may stay off the east coast of Florida where the strongest winds will miss the land.
      It will still be a huge mess but not as dire as it seemed up until earlier this morning.

    • Thor

      Thats a lot of hyperbole masquerading as speculation. Its likely when and if she makes landfall in FLA she will no longer be a CAT 5 (+++)

      • alanstorm

        And likely won’t STALL

    • SoCalWXwatcher

      Let’s not release the Kraken just yet. As others have pointed out, various model solutions keep the worst of Irma offshore. Could be catastrophic, but maybe not. Hard to say 100+ hours out.

      People in Florida should of course plan and brace for the worst case scenario you’ve described, out of an abundance of caution.

  • Fairweathercactus

    NWS in Oxnard notes another heatwave on the way. Yet the GFS shows an upper level low hanging around the area for a while and brings So Cal rain on the newest runs. I think they are disregarding the GFS runs at the moment.

    • BRP (Ventura)

      It’s Oxnard! Do we need to dust off the old memories and remind all in So Cal of Oxnard NWS Office’ hate of moisture?!?!

    • SoCalWXwatcher

      It pains me to say it, but NWS Oxnard is probably right. Here in coastal SoCal, we’ve gotten less subtropical moisture than the GFS has advertised all Summer.

  • RunningSprings6250

    Sometimes….what else ya gonna do? LOL

    https://instagram.com/p/BYtA4TYjKuS/

  • CHeden

    A few snapshots from last evening’s “surprise” T’storm in Cottonwood that drifted west from Mt. Lassen. This cell was very active up until it moved over my house, then squat. Amazing how fast these things can pop up then settle down.
    Bolts were REALLY close, with deafening thunder….all less than 1 second after the bolt.
    Should be some more storms in the Lassen area again today, but not as extensive. Tomorrow though, should be more active as moisture from Lidia gets pushed inland by a CF/trough now approaching the NW coast.
    https://uploads.disquscdn.com/images/8a907f5e3ac90dc6cb44849ac84270cc284308a6daa2bd7486963ffd573762d8.jpg https://uploads.disquscdn.com/images/c039e145a950c8bc25ecd5c92195e0241098bab4e48776d027caeb2fefdf294d.jpg https://uploads.disquscdn.com/images/e1743bce22c14f8639c47969a2557fef44c8da4cd31c5c4508c2fc330dab0d6a.jpg

    • BUST
      “This cell was very active up until it moved over my house, then squat.”
      You have a good trigger finger nice catches!

    • 805 Weather (Camarillo)

      That’s the sweet stuff!

  • CHeden

    This morning’s WV nicely shows the CoL off the cent. coast. The low will be pushing inland later tonight and Thursday as the trough to the west of the low pushes east. Our chances for more activity will strictly depend on when the low starts to push inland. ATTM, the HRRR is showing all of the appreciable activity stays over the Northern Sierra and southern Cascades. https://uploads.disquscdn.com/images/298533b533893757932c62b0e1c4357988d2531ebc22365f290a19def99354bc.gif https://uploads.disquscdn.com/images/3977ae26028938dd8b043b5fc6c5ba1d9f01adf57e25ae0ef47acff45b85ad8e.jpg

    • Thanks for these updates IRT CA weather 😉

      • CHeden

        Yer welcome. As you know, I’ve been rather obsessed with this “Lidia” event for quite a while now….and so far things are pretty much progressing as expected.

  • Rainmaker (San Jose)

    saw this on Facebook, so far its working on the GFS 06z, maybe the folks in South Carolina need to see this
    https://uploads.disquscdn.com/images/9aa4e8bddcad8f95a36af09694435764ca3399aa85d9a48342b97e7a92020682.png

  • CHeden

    OT, but of note: Twin X-class flares have erupted from the sun in the last 12 hrs, with the second one an X9.3 intensity. Very surprising since the sun has been steadily falling into a deep slumber as solar minimum approaches. The X9 flare is the strongest in over a decade according to Spaceweather.com.
    The flare unleashed a CME and proton storm that has caused radio blackouts….mostly over Europe.
    The CME appears to have been at least partially geoeffective, and according to NOAA, there is a 90% chance of a potent solar storm with auroras over the northern latitudes once the CME arrives.
    https://uploads.disquscdn.com/images/a6a853eb30fcefdd0a841406fb3f25a410b18a907be1552da7c9b482461b741a.gif

  • Jason Jackson Willamette
    • CHeden

      You’ve been providing some excellent data grabs! ATTM, the satellite is indicating Irma’s WNW track will keep the eyewall just offshore (north) of Puerto Rico…so they may escape the very worst of the storm.
      Thanks for keeping us updated with the latest.

      • Jason Jackson Willamette

        Thanks CH. It’s not looking good for St. Thomas and St. John right now. Near 160mph winds predicted, or HIGHER! Gawd.

  • matthew

    The day has started out humid with quite a bit of overcast and not much heating. Still only in the mid-60’s at 10 a.m. Question if lack of heating will limit the t-storm development later this afternoon.

    Also, saw my first flock of geese heading south (30+ of them) yesterday. Compared to last year they seem to have arrived a few weeks late. The deer migration however, is right on schedule as the overgrown rodents have been munching down on my landscaping!

    • CHeden

      We’ve seen a few coming down the main Sac river since last week…but so far just small flocks (like you saw). Our osprey have cleared out with two chicks in tow….and now the vultures have taken over the nest. The doves are in though, and in good numbers. The sound of shotguns in the morning are not my wife’s cup of tea, though.

    • Charlie B

      Lack of heat is my concern down here in Reno re thunderstorms.(I generally like a lack of heat but not when we need it to set nature off. Reno AFD a day ago mentioned the possibility that cloud cover might inhibit storms.)

  • Nathan

    Would be cool if Jose Fujiwhara’d/weakened Irma away from the coast…unlikely but possible if Jose rides the westerlies and Irma stalls!

  • Thunder98 (Santa Maria Valley)

    It’s only 63F and its 10:25PM

    • CHeden

      In Europe?
      LoL!

      • Thirstier Nick (Santa Maria)

        Nope, here. Marine layer looks thick today.

  • 805 Weather (Camarillo)

    Latest GOES-16 imagery would suggest the entire state is within a bit of a convergence zone this morning as the hybrid remnant low of what was Lidia still sits off our coast for another. Over the next 42 hours a trough over the GOA digs south into the low’s vicinity however this trough pick’s Lidia’s remnant low up in it’s cyclonic flow & pivots it along the north coast before they eventually merge. With the state being between Lidia’s remnant low’s cyclonic flow & the ridges’s cyclonic flow, this weak statewide convergence zone has now formed… The question is, how long will it last and will the associated pops increase during peak surface heating timeframe embedded within the southerly flow. There was a bit of steeper lapse rates over the eastern half of LA County, the Antelope Valley and Orange County as well this morning. This caused some spotty light showers in San Bernardino county, but has since diminished.

    From what I can tell SoCal is in the weakest part of this convergence zone, and the lapse rates lift north, but generally in the region stay unchanged due to the synoptic setup we have at play. This new cutoff low forming on our coastline isn’t alone however, as there is a weak easterly wave currently over the southern GoC moving WNW right for the CoL… PWATS are really high still across the state, generally in the north state, however the easterly wave that is sitting over southern GoC might be timed just right to aid in giving the cutoff low an influx of moisture. & since the low is out of the north from the GOA, it has a bit of the advantage to colder air for a more conducive environment for instability. The Euro was even showing some of that 32-36°F air in the 700mb layer hanging out on the Central Coast. This is going to be interesting to watch play out. https://uploads.disquscdn.com/images/bab1efdd13e14e400d31646b20e025b759e8a93e23eac51e8793c1655dd597d1.gif https://uploads.disquscdn.com/images/689c810a617dedcbac7dc1cd406bbf3f99fa83f76ca4f2f6c75e09aa1a596bfd.gif https://uploads.disquscdn.com/images/4ff9a8eae2165d205cf454a8fe5fd65a87ec0ce307153a1703a435ded4efc822.gif

  • 96 hour simulations like these are…terrifying. Models have converged on a South Florida track, but relatively subtle shifts of 100-150 miles east/west–which are still entirely possible–will have possibly existential consequences for Miami. What a nightmare. https://uploads.disquscdn.com/images/997b4f76745cc4d9f16d88d41170f536c6366d8fc3f112673393d4694b5dedf5.png

    • CHeden

      After following your commentary for many years, I can’t recall you ever using such descriptive language as “terrifying” to describe an upcoming event like this. I think the tone of your post speaks volumes.

      • Homes were ripped to foundations with Andrew. IMO Irma will replace Harvey which replaced Katrina which replaced Andrew.
        On a side note the sad part about Harvey was the small % of folks who had flood insurance. In Florida almost everyone has windstorm coverage and would be a requirement from a bank when lending money. This may put a larger strain on financial markets than Katrina and Harvey and maybe Andrew combined…again IMO

    • 12z ECMWF nearly identical. Yikes.

      • 805 Weather (Camarillo)

        Was just about to say…

    • Thunder98 (Santa Maria Valley)

      Is it possible it can curve and go out sea like Hurricane Bill did in 2009

    • weathergeek100

      Even if the eye wall is 50-100 mph offshore it’s going to be awful.

    • 805 Weather (Camarillo)

      Edit: Nevermind that. I had the Category wrong.

      • But Matthew didn’t make landfall in Florida! Latest guidance suggests a direct hit is possible near Miami. The impacts in that outcome would be incomparably worse.

        • rob b-Truckee/East Bay

          Could be very scary and also interesting, Miami has built up so much along the beach in the last 15 years. Could be a real test for updated building codes and also if some of those buildings skirted some codes to be built faster.

          • weathergeek100

            Yeah, exactly how much wind can those updated codes withstand? I’m curious. My guess would be upwards of 180 to 200mph so we’re just on the fringes here.

          • rob b-Truckee/East Bay

            Also wonder how the large buildings will change the winds patterns. We know large buildings funnel winds, but when winds hit 100+mph and are funneled that would get very interesting.

        • 1992 Andrew was about as close as a hurricane could get before being a catastrophic event for Miami. Effects of Irma with a bullseye on Miami would have global financial impacts.

          • weathergeek100

            True. Miami is a world-class city. Capital of Latin America in many cases.

          • …..and almost everyone has windstorm insurance.

    • Chris

      My cousin just bought a new house in Miami. 4 mo/old baby too.
      My other cousin and my aunt each own a home next door to each other up in Ft Pierce.
      Look at “St Lucie” and go due east and under than line is their homes.
      Not fun. https://uploads.disquscdn.com/images/5481ebcca56a2dba871ed59079d3407fc4494b94b20914635d76f8882e96bc47.png

  • weathergeek100

    Look at #3- that video posted earlier is actually from a tornado a year ago. It is NOT hurricane Irma. https://www.buzzfeed.com/janelytvynenko/irma-misinfo?utm_term=.atM6DJMQoB#.pyma2pBMw0

    • Jeff

      yeah, the storm came through at night as well

      just need some good shark pictures to go with it

  • Thunder98 (Santa Maria Valley)

    The forecast high today is 81F and its only 64F with marine clouds right now

  • Jason Jackson Willamette

    Updated radar image out of San Juan, PR. St. Thomas has been under the southern eyewall for a couple of hours now, which according to the Weather Channel prognosticators, is a solid wall of 40,000 feet high thunderstorms… We cannot even imagine what this is like, living in California.

    https://uploads.disquscdn.com/images/c0f180978097807f47a71f4e72bd56151c71601ba0661e474ffdc407475e3745.jpg

  • Jason Jackson Willamette

    Wind speeds destructive power is illustrated by this example. The power of exponential determination.

    Cat. 1 storm, x1
    Cat. 5 Storm, 500x more destructive.

    Holy wee cows.

  • Thunder98 (Santa Maria Valley)

    Feels like June Gloom or May Gray

    • Hollow Scene (Riverside)

      Not over here, it’s pretty muggy!

  • weathergeek100

    New building codes after Andrew….for a time.

    “Rather than embrace the success of the new codes, however, the state started walking them back.”

    https://www.usatoday.com/story/news/nation/2017/08/10/hurricane-andrew-florida-building-codes-weakened/490364001/

  • RunningSprings6250

    Who’s this peaking in, hurricane Margarita? Dolores’ promiscuous younger sister?!

    https://uploads.disquscdn.com/images/a95490d1ee06b2b0b9aab8216cebec7b171d3037996bd70012d6d676a164617c.png

    • AntiochWx

      Paging crouching Dallas!

  • Nate
    • weathergeek100

      Yeah, I noticed that. Watching this low very closely!

    • Rusty Rails

      Looks like we might get clipped in Santa Cruz, and somewhere across the SC Mountains seems likely. Karl burned off a couple hours ago so sun is making it through the mid level clouds for some ground heating.

    • Stefan Myslicki

      I was just coming here to see if other people were seeing this also!! Showing up well on KMUX radar too!!

    • Cool!

    • alanstorm

      The Lightning is most certainly NOT welcome for obvious reasons

  • SoCal Al (El Monte-SGV)

    Interesting weather scenario developing for SoCal Fri/Sat/Sun, though I’ve been stung numerous times this summer with the monsoon and hopes of rain.

    Progs are showing an upper level trough that develops into CoL to our west spinning up a pool of tropical moisture from NW Mexico and the Gulf of Cal northwestward. This could potentially bring us a good round of convection and rain showers depending how far west the plume of moisture advects. All surrounding NWS offices are teasing with this scenario while as usual Oxnard mentions slight chances to our east. It’s all dependent on how far south and west the CoL sets up and if the HP positions itself in a favorable area to provide a strong southeasterly flow for us.

    The ingredients are coming together for possible excitement, or will it be just another case of hopeful expectations gone awry.

  • tomocean

    This is mesmerizing. Should be useful for our upcoming storm season as well. They do need to up their wind speed gauge a bit though.

    https://www.windfinder.com/#7/18.235/-62.930

  • cthenn

    I guess people still have to get their pre-hurricane tanning in…
    http://www.earthcam.com/usa/florida/miamiandthebeaches/?cam=miamibeach1

  • Cap’n

    Thunder, lightning, rain oh my in Tahoe City. Watching that red blob on the lake driving to KB in a minute. Sky is wicked.

    https://uploads.disquscdn.com/images/fcf12cd9f0f0dfc7e2561b36d80ff55053ce6cc0258d41a2d33393ee90503cf1.png

    • rob b-Truckee/East Bay

      Looked like a lil action around the West end of Donner Lake was kicking up too.

    • AlTahoe

      Trees are dancing here in Incline Village with some thunder.

    • Cap’n
    • mbmattcor (TD 6400′)

      it’s booming in TD, starting to hail…bring it! @summitsteve:disqus pm me your cell number, so I can show you our TD trail offerings.

      • Cap’n

        I have no clue how to PM. Just did a fun ride in Soda Springs, got poured on though.

    • matthew

      Booming in the shire. No rain yet, but it should be here soon.

  • rob b-Truckee/East Bay

    Looks like FEMA has decided to stage many of the USAR crews that were originally leaving the Houston area; now being sent East to stage in the Alabama area. Seems to make sense to me, why send the back West to only reactivate them 24-28 hours later to head further East.

  • Wrangled (Stockton/Graeagle)

    Drove over Carson pass this morning and was surprised to find the ground covered with hail from the previous evening! Almost thought it was the season’s first snow…They got pummeled! Cal Trans had one lane open as they were removing mini mud slides and debris from the road.

  • Cap’n

    Orgasmic storm in Tahoe Vista. Me and my dudes are pulled over watching and laughing like madmen. The wind, waves, lightning and sheets of rain are the best I’ve seen this summer.

    • Jason Jackson Willamette

      Go dance in the rain for us Cap’n. We need to show the Weather God’s we welcome the storm!

      • Cap’n

        Storm chasing with developmentally disabled adults (think 3 Rainmen) is an experience no one should miss out on.

        • SoCal Al (El Monte-SGV)

          Bet they’re excellent drivers…………

  • Thunderstorm

    Then all of a sudden there is action all along the Sierra foothills. How big and where will it go?

  • Jason Jackson Willamette

    Yeah, I know, it’s the GFS, but still ….. – If this comes to fruition, just wow….

    https://uploads.disquscdn.com/images/5b7a2a65a4517a615bf5dbdf342ab5b6f8042e05a551a4bf713da4aadb9eddfd.jpg

    • AntiochWx

      Mar a Lago and Miami thumper.

    • 82/83 El Nino baby (San Jose)

      Seems impossible, but given what Irma has been doing, I won’t say its completely out of the realm for 890MB.

      • matthew

        890 while coming onshore at Miami would make Houston look mild.

      • Thunderstorm

        Some areas of water off of Florida are the warmest,gulf stream. To the NW of Cuba are the warmest waters yet to come yet for Irma.

        If Irma had a nick name what would it be? Irma sounds to weak too me.

    • Thirstier Nick (Santa Maria)

      This needs a skull and crossbones in the black area.

  • rob b-Truckee/East Bay

    While not as exciting as what’s taking place in the Sierra, clouds have moved into the East Bay, maybe we’ll be seeing some action tonight.

    • matthew

      The fire hose has just turned on over here. From zero to dumping in about 2 seconds.

      • rob b-Truckee/East Bay

        if the future model is correct-looks like around 6pm could get really interesting in the Truckee area.

        • Cap’n

          I’m stuck on 267 watching constant lightning above my house and black clouds. Must be nuts over there.

      • Cap’n

        Trying to rush home before that red blob gets to my house before my dog has a panic attack. The blob is going to win.

        https://uploads.disquscdn.com/images/ab3f1f7b2d2e50949e4c0590dedc83ef57e241c67afad87f491b37ce96ed48d1.png

        • matthew

          Hate to break it to you, but I think your dog has already shit the carpet.

          • Cap’n

            That one made me laugh! He’s pretty good, he just pants really heavy and paced, at least so far…

  • Nathan

    Question for the model wizards:

    in what way does rotational inertia affect modeling a hurricane trajectory? For example, if a frisbee is slowly flying by, spinning at 20,000rpm and you “poke” it, it has such a tremendous amount of inertial energy that its trajectory will barely be affected. But if it’s spinning at 60rpm and you “poke” it, your poke will affect the trajectory considerably.

    Obviously a hurricane is not a frisbee, but it does have some similarities in that a disc of warm air moving at 180mph around a central axis has far more rotational energy than a disc of warm air moving at 60mph around a central axis (or does it _not_ actually, because it’s a fluid?)

    So my question is, do models accurately take this into account? If a storm is more powerful than it is projected to be, is it therefore going to “budge” less than it is projected to budge, and vice-versa, ie, less powerful storms are easier to perturb and therefore harder to predict?

    • Jason Jackson Willamette

      Not a definitive answer to your question, but this is a basic law of physics, as explained by –

      “Newton’s first law of motion describes inertia. According to this law, a body at rest tends to stay at rest, and a body in motion tends to stay in motion, unless acted on by a net external force.”

      it’s well explained here:
      https://www.boundless.com/physics/textbooks/boundless-physics-textbook/the-laws-of-motion-4/newton-s-laws-46/the-first-law-inertia-236-10947/

    • SoCalWXwatcher

      A hurricane is more akin to a stack of frisbees, each rotating at a slightly different rate, and not always 100% in synch, with he frisbee at the top of the stack actually rotating in the opposite direction as those on the bottom.

      http://www.srh.noaa.gov/jetstream/tropics/images/hurr_cross.jpg

      • Jason Jackson Willamette

        That is an excellent graphic!

      • Nathan

        but….question not answered….

        • SoCalWXwatcher

          I think the mechanics for a hurricane are far more complex, since they are vortices that spin with greater speed near their center (the opposite of a flat, spinning disk) but I’ve searched and have been unable to find anything that would confirm or negate the idea that a more rapidly spinning hurricane would be touger to deflect from its course than one that is spinning more slowly. Perhaps a pro like Daniel could weigh in on this.

          It would make sense that a more rapidly spinning hurricane (with obviously stronger winds and more potent curculation) would be a deeper system with more momentum, but I’m not sure how much centrifugal force would play into that. The eyewall appears to be where balance/equilibrium occurs between the centrifugal force of the rotating winds and the inward “pull” of the low pressure center, hence the eyewall structure, and the lack of clouds in the eye. With those forces in balance, I’d tend to discount the idea of a hurricane having any “momentum” in a particular direction, but I’m probably wrong.

          • Nathan

            thanks.

    • Bombillo1

      Without observing and seeing actual data, I would guess this is so..

  • SoCalWXwatcher
  • AntiochWx

    Party in the city where the heat is on…Yo I heard the rainstorms ain’t nothing to mess with.

    • RunningSprings6250

      So the question is….is this categorized as a ‘summer’ event or early fall?

      • SoCalWXwatcher

        Meteorological Fall or Astronomical Fall? 😉

        • RunningSprings6250

          Hey now no funny business mister! LOL!

          • SoCalWXwatcher

            Meteorological Fall started on September 1st. So you can call it an “Early Fall” event as you sip your pumpkin spice latte. 😉

        • Yanet Garcia (NYC, USA)

          I fall on my knees

  • AntiochWx

    GFS NE bias is showing, would go blend of Euro/GFS. Miami is in trouble. Verifications south of GFS track. https://uploads.disquscdn.com/images/c2db4e01edb067902a385762e122f5565889e76c3448f6f9003648d08ccdde30.png

  • mattzweck
  • Candleman (Santa Barbara)
  • AntiochWx
  • mattzweck

    not to over emphasize anything.
    https://youtu.be/-L4qHjmsgYE?t=1m10s

  • Sokafriend

    I just heard that the intensity of Irma’s waves are affecting seismographic readings.
    Has anyone here seen a more specific reference to that seemingly unique occurrence?

    • Nate

      Yep, this is a relatively common phenomenon. Some of the energy from the swell hitting the islands is transferred to seismic waves, which can be seen on the Caribbean seismograms. A smaller portion of this noise is from the actual wind moving across the land. If you check California’s seismic network during a big swell/windstorm, you’ll see the same thing, but usually on a smaller scale.

      https://twitter.com/seismo_steve/status/905313867647070208

      • Sokafriend

        Thank you so much- I’ll check it out.

  • Thunder98 (Santa Maria Valley)

    Heaven for the next several days. Whats with that slight chance of thunderstorms on Monday? That came out of nowhere!

    https://uploads.disquscdn.com/images/9c86f96c7dae16301630f2d5e13daf283507d0895641611dd76ab3119cd85e46.png

    • RunningSprings6250

      Because pumpkin spice…

    • Thirstier Nick (Santa Maria)

      Could the Central Coast be a bullseye for that cutoff low?

  • SoCalWXwatcher
    • TheNothing

      Wow!

    • max

      If there is a silver lining, it is the fact that the grid is still up, lights are on, and refrigeration is possible. Big plusses for the local Engineers, and planning people..

  • John

    So what I’m wondering is where Mar-a-Lago is in respect to Irma’s possible path?

    • Candleman (Santa Barbara)

      Wondering or hoping?

      • John

        Not really hoping.

        I guess the sentiment is that, if Irma does affect MAL, or even if not, at least it might underscore both the necessity for recognizing climate change (no matter the cause), and for authorities to plan measures that mitigate its effects as best as possible .. . something the latest weather news shows that the private sector can’t do, and that sometimes government is not the problem, but the solution.

    • SoCal Al (El Monte-SGV)

      Palm Beach, just north of Fort Lauderdale and Miami. Needless to say it may be under water since it sits on a key offshore.

    • AntiochWx

      Very close to PB. Elevation is I think 17′ . So storm surge + waves will cause a lot of erosion in that area, plus the pounding winds.

    • Uncle Jesse

      That one’s getting old, john.

  • Admode (Susanville)

    Uhh,

    “Gaston Browne, prime minister of Antigua and Barbuda, said Irma had destroyed 95 percent of the structures on Barbuda, an island with about 1,600 people.”

    https://www.nytimes.com/2017/09/06/us/hurricane-irma-caribbean.html?smid=fb-nytimes&smtyp=cur

    • Jim

      That video that someone posted pretty much confirms that…pretty sad for those people

      • Admode (Susanville)

        I didn’t see the video but I’ll look for it. It is sad indeed.

  • Cap’n

    I found out today that a long time AA legend and a man who saved my life years back has passed on to the other side. He lived a long full life. I think I saw him up in the sky today after finishing a great bike ride. Life is good, everyday above ground is a victory. My thoughts and prayers go out to the people suffering through these natural disasters. Praise be to Jah.

    https://uploads.disquscdn.com/images/2d83f492bbe5525c9702c9cdf55ee2e4e31a3a2ef96bcbfc663d68eed4a8807d.jpg https://uploads.disquscdn.com/images/903889265ceac8568e5e5eaeec6072f2459e015be91d8bce2598092345753a11.jpg