Monday Forecast

210 Comments

6:20PM

DAYS 1-5 (SEPTEMBER 4-8)
Apologies for the very late update today. We had a nice Labor Day, guess I don’t have to forecast it since it’s over. 😉 No major changes anyway to this forecast going forward. Summery Tuesday. Cold front approaches late day and evening and send thunderstorms into areas well northwest of Boston that die out and then the line becomes stationary or even backs up for a time in the nighttime hours and awaits a small wave along the front to go by before pulling eastward Wednesday. This day becomes the showery day for much of the region, and then some eastward progression is expected Thursday which should have a drying trend and set up decent conditions for the Patriots opening game at night. Another front may come along and produce a passing shower Friday.
EVENING: The sun will set in a mainly clear sky. Temperatures in the 70s, some 60s South Coast. Wind W 5-15 MPH.
OVERNIGHT: Mostly clear to partly cloudy. Lows 58-65. Wind SW 5-15 MPH.
TUESDAY: Partly cloudy. A late-day or evening shower or thunderstorm may reach north central MA and southwestern NH. Highs 75-80 South Coast, 80-88 elsewhere. Wind SW 10-20 MPH and gusty.
TUESDAY NIGHT: Variably cloudy. Chance of showers/thunderstorms, mainly well west of Boston from eastern CT through central MA and southwestern NH. Humid. Lows 63-68. Wind SW to variable 5-15 MPH.
WEDNESDAY: Mostly cloudy. Episodes of showers/thunderstorms. Humid. Highs 70-75. Wind variable 5-15 MPH.
THURSDAY: Variably cloudy. Showers most likely in the morning, diminishing chance thereafter. Lows in the 60s. Highs in the 70s.
FRIDAY: Partly cloudy. Chance of a shower. Lows from the upper 50s to middle 60s. Highs from the middle 70s to lower 80s.

DAYS 6-10 (SEPTEMBER 9-13)
Fair and cooler for the weekend of September 9-10. Fair and warmer September 11-12. Risk of rain at the end of the period depending on the track of Hurricane Irma. It is unlikely that we would see a direct impact here. It would likely range from remnants to a side-swipe, depending on the eventual path of the storm.

DAYS 11-15 (SEPTEMBER 14-18)
A rain risk early again depending on Irma’s eventual track, then a drying trend.

210 thoughts on “Monday Forecast”

  4. Good evening and thank you TK.

    18Z GFS has the track a bit more to the East.

    Here it is approaching SOuth Florida

    https://www.tropicaltidbits.com/analysis/models/gfs/2017090418/gfs_mslp_pcpn_frzn_seus_23.png

    https://www.tropicaltidbits.com/analysis/models/gfs/2017090418/gfs_mslp_pcpn_frzn_seus_24.png

    https://www.tropicaltidbits.com/analysis/models/gfs/2017090418/gfs_mslp_pcpn_frzn_seus_25.png

    https://www.tropicaltidbits.com/analysis/models/gfs/2017090418/gfs_mslp_pcpn_frzn_seus_26.png

    https://www.tropicaltidbits.com/analysis/models/gfs/2017090418/gfs_mslp_pcpn_frzn_seus_27.png

      1. Word in the street was someone was cleaning koopmans out of plywood. Milk and eggs were gone in the whole area also.

  6. I’m flying to California the morning of the 20th. Think I should change my flight based on a 384 hr GFS run? 😉

    1. Porcelblow strikes again. It’s amazing how he has set the tone for so many of his starts this year by giving up runs in the 1st inning. Makes it that much harder for an already anemic offense to get back in the game

      1. Agree. They suck and I don’t care what y2k says. Pathetic. Interesting as soon as Pedro is comes back they start losing. Coincidence? You be the judge.

  12. With the fear of being labeled a negative nelly, Sox are down 3-0 to the lowly Jays. Granted it’s the 2nd inning, but jeez talk about a fall. They gotta turn this around. If they don’t win the division, they’ll have to win that one wild card game, then play the Astros. Even if they win the division, they’ll play the Indians. No easy task either way the way they’ve been playing.

    1. You’re entitled to your opinion and I’m going to spare you and everyone else the hyperbole for this evening. 🙂

  15. Wow, that is one bright background! Red Sox are killing me… starting to feel like a September collapse. They’re so hot and cold though, they hit a stretch like this but then go win 8 of 10. I think it’s a recipe for another first round exit. Excited for the Pats to open up. I have some concerns with them on the defensive side. Not sure what that unit will look like. Regardless, glad it’s football season again.

    Irma is a buzzsaw. As its new, larger eye continues to clear, continued strengthening is likely. Category 5 possible tomorrow. 00z models tonight will have ingested some additional data from upper air reconnaissance missions. In a situation with some very sensitive features in play, we’ll see if that makes a difference.

        1. I love all the different ones the NHC has on their site.

          CDO (central dense overcast) is really symmetric, and as you point out, the cloud tops continue to cool. Back in intensification mode.

    2. Holy Crap. That would shatter the record for the strongest Atlantic hurricane in recorded history. The Keys would be obliterated!

  17. Forgive me for playing the straight man if that was a joke but is this becoming the strongest recorded Atlantic hurricane actually a viable possibility? Also as always I’m very concerned for the St. Boniface hospital and villa / mobile clinic on the southern peninsula of Haiti. They are still reeling from Matthew last year. Any thoughts / educated guesses on how this might impact Haiti yet or are we too far out? Thanks!!

    2. The output of the HMON model that Dave posted above had it down to 869mb. Record lowest pressure to date for an Atlantic hurricane is 882mb. So yes, it would shatter the record if that model verified (which it wont as TK said).

  19. So for the last couple hurricanes, the GFS has been coming out with unreasonably low, record-setting pressure forecasts. I think we have seen more than enough to know (as if we didn’t know before the upgrade) that the model does not perform well regarding the strength of tropical cyclones. I expect this to continue until the mistake of implementing this version of the GFS is fixed.

  21. I’m confused on the projected pressures …..

    When I look at instant weather maps, I think it says 965.2 mb at landfall. (00z GFS)

    1. Tom, 0Z GFS

      https://www.tropicaltidbits.com/analysis/models/gfs/2017090500/gfs_mslp_pcpn_frzn_seus_22.png

      https://www.tropicaltidbits.com/analysis/models/gfs/2017090500/gfs_mslp_pcpn_frzn_seus_23.png

      6Z GFS

      https://www.tropicaltidbits.com/analysis/models/gfs/2017090506/gfs_mslp_pcpn_frzn_seus_21.png

      https://www.tropicaltidbits.com/analysis/models/gfs/2017090506/gfs_mslp_pcpn_frzn_seus_22.png

      https://www.tropicaltidbits.com/analysis/models/gfs/2017090506/gfs_mslp_pcpn_frzn_seus_26.png

      1. Thanks JpDave.

        I don’t doubt them, I just don’t understand why the instant weather map pressures don’t show 888 mb …..

        1. Almost impossible to read the pressure on a deep
          hurricane like this as the isobars are just too tightly packed. I just tried with Zooming in and gave up. 😀

    2. Looking at this, one might deduce the Irma was destined to strike the
      Gulf Coast somewhere. However, there “appears” to be a Fairly sharp
      Right hand turn in it’s future. We shall see.

      The CMC does take it to the Gulf around Pensacola, FL or so:

      https://www.tropicaltidbits.com/analysis/models/gem/2017090500/gem_mslp_pcpn_frzn_seus_30.png

      JMA somewhat similar

      https://www.tropicaltidbits.com/analysis/models/jma/2017090412/jma_mslp_uv850_eus_8.png

      NAVGEM

      https://www.tropicaltidbits.com/analysis/models/navgem/2017090500/navgem_mslp_uv850_eus_26.png

      Of course those are 3 of the worst CRAPPY models. 😀 😀 😀

        1. 966 mb as best I can determine, A Cat 3.

          This would not be good, but then it looks like NONE of the scenarios are good.

  25. Before I head off to work, I leave you with the following for the HMON.
    Click on FWD to view a loop.

    http://moe.met.fsu.edu/cgi-bin/hmontc2.cgi?time=2017090500-irma11l&field=Sea+Level+Pressure&hour=Animation

    And here is a still

    http://moe.met.fsu.edu/tcgengifs/hmon/2017090500-irma11l/slp42.png

    NOTE: Presssure 869.8 mb
    Winds: 151.6 knots OR 174 MPH !!!

    Let that sink in for a few moments.

    Again, it’s one model. It’s new and replaces the old GFDL and I have no clue
    how good or bad it is. 😀

  27. Data from a NOAA hurricane hunter plane indicates that Irma is now a Category 5 hurricane. I would expect that upgrade by 8AM.

        1. That one is a flight level reading, so it’s too high. NHC usually uses some blend of the extrapolated ten second and thirty second surface winds, which to me support 150kts.

      2. Yes. There’s actually two planes in the storm now, both getting winds into the 150kt range. I would expect 150kts/170mph on the next update. A Cat 5, and not a borderline one either.

  28. NHC track should start to show a gradual shift north today. They don’t like to jump all at once.

    Just talked to a trusted colleague who has a similar idea to mine.

    Today’s update will be a bit late again, but not as last as yesterday’s.

  29. In lieu of the typical intermediate advisory, NHC will be issuing a full special advisory at 8AM to reflect the dramatic strengthening of Irma. 175mph.

  30. Is there anything in the next 4 to 5 days that could provide shear to the system ?

    A slight northerly shift in track would decrease the land interaction with Dominican Republic and Cuba.

  32. I was curious and many probably already know the information. The lowest recorded pressure in a hurricane was for Wilma in 2005 at 882….in the Atlantic basin and until 2015 in the western hemisphere until Patricia. Patricia (872) was second most intense tropical cyclone behind Tip (870) in 1979

    The strongest recorded winds were “Hurricane Camille of 1969 had the highest wind speed at landfall at an estimated 190 miles per hour when it struck the Mississippi coast. This wind speed at landfall is the highest ever recorded worldwide.”

    Please feel free to correct if my information is inaccurate. It is what I found online but you never know.

    1. Yes. Accurate info.

      Intense tropical cyclones are not really clustered anywhere in observed history, rather dotted upon it sporadically.

  33. In the office and a thank you to WxWatcher for the update on Irma.
    I am not the slighest bit surprised that it has been upgraded to a CAT 5.

    The HMON has been advertising that all along, so perhaps it’s not so far off.

  34. Wow, Irma is looking extremely intense right now. I don’t think those islands will be able to get through this without massive devastation. Does anyone know if they can be evacuated?

  36. Locally, we seem to have a severe threat that’s flying under the radar. SPC has the area in a marginal risk with a slight risk covering much of New Hampshire and western portions of SNE. We have the entire trifecta in terms of specific risks -wind, hail, and 2% tornado. Although from what I heard elsewhere, this would be mostly a straight line event, so not completely sure on that tornado potential.

  37. thank you Bost and JJ. What is the timing on this? I’m headed out mid day to an appointment in Wellesley and would be happy not to be driving.

  39. Interesting stat on Irma I just saw posted on twitter from Philip Klotzbach.
    #Irma is the furthest east in Atlantic that we’ve had a 175 mph hurricane on record (57.7°W). Previous record: David-1979 (66.2°W).

    1. Interesting indeed.

      I also second JPD….the conversation here is fascinating. I love my WHW family and its shared enthusiasm for weather.

  41. Irma right now the strongest Hurricane in the Atlantic since Felix in 2007.
    Bucs Dolphins game maybe impacted Sunday as NFL a conference call this morning whether to play or postpone the game. Kickoff scheduled for 1pm Sunday.

    1. IIRC Felix was a bit of a minx….sort of like its name would imply. Didn’t forecasters have trouble figuring its track and it finally came up east coast?

  42. Irma is now the strongest Atlantic hurricane at least in terms of wind since Felix in 2007.

    Pressure of around 930mb is well above what storms like Wilma and Rita had at their peak; recall what I said days ago about mean pressures in the Caribbean versus open Atlantic, and how a storm like Irma would be less likely to reach those extremely low pressures even as a Cat 5. That appears to have played out. Thus, while those GFS and HMON predictions for a sub 900mb/150kt+ Cat 5 have verified on wind, it’s clear Irma will never get down to those crazy low pressure levels even being the monstrous Cat 5 that it is.

    1. That may be so, BUT if those winds are accurate, then it matter little what
      the pressure actually is. Imagine 175 mph winds plowing into the greater
      Miami Area? Devastation the likes of which has never been witnessed.
      The last bad storm to strike that area was Andrew in 1992. There has been a great deal of new construction since then. More fuel for the fire as the saying goes. The area would be flattened. I shutter to think of the results.

      Let’s hope it takes an more Eastward jog with the guts of Irma remaining
      off shore.

      AND IF it ever tracked over the keys…….

      1. The keys terrify me. I’m wondering how long they will wait to evacuate. I said yesterday that it takes a minimum of three days.

  44. The HRRR is advertising a quiet day of weather for central and eastern New England today, with scattered showers and storms to the west. That sounds about right to me. SPC could probably afford to shift their outlook areas west a little. Action shifts east tomorrow and tomorrow night, with locally heavy rain and some isolated flash flooding possible, along with perhaps a localized strong thunderstorm.

    1. Central and eastern parts of southern New England I should say for today are quiet. Showers and storms possible today across all of VT, NH, and ME.

    2. As does the 3KM NAM. I’m with you on this one 100%.
      Tomorrow could be interesting around these parts, not so much for tornado, but
      for possible severe. At the very least some HEAVY RAIN with flooding
      potential.

  45. NFL really has to seriously think about moving that NFL 1pm game in Miami. Even if nothing happens in Miami better safe than sorry.

  53. If the 0z EURO were to verify bad for Cuba but would knock down a lot of the intensity going over mountains. If it misses Cuba like the GFS has been advertising bad situation for U.S.

  55. Irma now 180 mph storm pressure down to 931 mb.
    JPDave I would think that would qualify as a HOLY CRAP BATMAN!!!

  56. Latest update from the National Hurricane Center

    Max winds: 180 mph
    Pressure: 931 MB

    Link: http://www.nhc.noaa.gov/

    Latest Cone:

    http://www.nhc.noaa.gov/storm_graphics/AT11/refresh/AL112017_5day_cone_no_line_and_wind+png/145233_5day_cone_no_line_and_wind.png

    Hmmm
    Why does the NHC insist on taking it throught the Florida Straights before turning
    Northward? Are they expecting it to traverse the Gulf with a strike in
    the Eastern Gulf somewhere ala the CMC?

    Intensity forecast

    FORECAST POSITIONS AND MAX WINDS

    INIT 05/1500Z 16.8N 58.4W 155 KT 180 MPH
    12H 06/0000Z 17.2N 60.3W 155 KT 180 MPH
    24H 06/1200Z 18.1N 63.0W 150 KT 175 MPH
    36H 07/0000Z 19.1N 65.9W 145 KT 165 MPH
    48H 07/1200Z 20.1N 68.7W 140 KT 160 MPH
    72H 08/1200Z 21.4N 74.0W 135 KT 155 MPH
    96H 09/1200Z 22.7N 78.3W 130 KT 150 MPH
    120H 10/1200Z 24.4N 81.2W 125 KT 145 MPH

  58. Florida Keys would be crushed with that track if Irma follows the center of the cone which we know these tropical systems shift positions often. With that track no land to disrupt Irma.

  59. With winds of 180mph, Irma has entered the conversation of strongest hurricanes on record in the Atlantic in terms of wind speed. It is already the strongest on record outside of the Gulf or Caribbean. Allen, in 1980, had winds as high as 190mph, which is the record there. Not completely out of the question that she gets there, although I think she falls short.

  60. Also, we now have “Jose” behind Irma. It is forecast to become another powerful hurricane in the days ahead. No immediate threat to land.

  61. Thank you for the birthday wishes Vicki and Tom!

    My birthday wish is that our good friends in the Florida Keys will be spared the worst of Irma.

  63. Stat on Irma from Ryan Hanrahan.
    180 mph sustained winds now tied with Mitch and Rita for 5th strongest in the Atlantic. Pressure much higher than those, however.

  66. There have been 6 Atlantic hurricanes before Irma with sustained winds of equal or greater intensity.

  71. Update: Newest @NOAA_HurrHunter recon just found 160kt or 185mph winds; Means #Irma may have just slid into a tie for 2nd strongest H winds

      1. Just lovely she said dripping with sarcasm.

        Clouds have been building for a bit. I was watching them come toward me as I drove west from Wellesley.

  77. This may have been stated already. There is a mandatory evacuation in place for tourists in Keys starting tomorrow am. It is my understanding that staggered mandatory evacuations will start after that. Florida has been declared a state of disaster and a few hundred national guard troops have been activated. I believe they have 7000 at their disposal.

    1. Where in Georgia? Best be well inland. Don’t have them go to anywhere close to the coast as IRMA “could” land there.

      1. Thanks for this info JPD. I will definitely pass it along to her. She has four little girls ranging from 8 months to 10 years old so I am just glad they are getting the heck out of Dodge!

    2. I’ve been to Islamorada many times. It is a lovely key! Will keep them and everyone in the keys in my prayers.

  80. 12Z Euro coming out. NOT impressed with the pressure initialization to say the least, but that has been discussed before.

    Initialized at 962 MB and progged at 24 hours to be 966 MB. That is so BOGUS it
    isn’t even funny!!!!

  81. Irma now 185 mph category 5 storm. Tied now for 2nd in terms of wind speed with Wilma Gilbert and The Hurricane of 1935.

  86. JPD – I noted you advised Sue to not have her friends go near the GA coast. This would not be strong enough to go into Atlanta would it??

    1. I wouldn’t think so, even if it goes up that way. Atlanta is a loooong way
      inland. “should” it go that way, I would think rain and possible Irma
      spawned tornadoes would be the main threat. Again, I say IF.

      Based on the 12Z EURO, that would be highly unlikely.

      I am concerned about the model divergence. Something is at play here.

      1. Thank you, JPD. I spoke to my sister in law after I’d asked here, and they are being told exactly what you just said to me.

  89. IF that tracks hold as I said earlier bad for Cuba but would knock it down some with the mountainous terrain there before impacting the U.S.

  92. JPD – I passed along your advice to my friend and they will be staying in Morganton, Georgia which is north of Atlanta, close to the Tennessee border. They are renting a nice lake house as they figure they may as well make a vacation out of it as they aren’t sure they will have a house to come home to when all is said and done. Certainly praying that is not the case.

    1. Perfect, regardless of the path. They should be plenty safe there.
      Depending on the track they may get good and wet, but should stay safe.

  95. Wasn’t someone on here going on a cruise to Bermuda in a week or 2? Will now TS Jose pose a threat to the island?

  96. Thanks, TK.

    Happy Birthday, Sue.

    I’m `lurking’ these days (looking at the blog but not posting). It’s interesting to follow the hurricanes, though the destruction is heartbreaking. First, Harvey and now an intensified Category 5 Irma. It would seem that part of the reason for the intensification is the fairly flat westward path Irma has taken – across perhaps the warmest sector of the Atlantic.

  99. Unfortunately, St. Maarten is going to experience the core of Irma. Mass devastation. I used to enjoy watching John Hope on the tropical update 48 minutes past the hour during storms like this. Those were the days. My thoughts and prayers are with the folks who reside on the Leeward Islands and anyone else in the path of Irma.

    1. I feel for them. Having been there before, I know the layout of the island.
      And the construction there, well, it isn’t so grand. I hope for the best.

    2. I was just reading the online newspapers in St. Maarten. Having visited that island many times my heart breaks for them. The airport was closing as of 2 pm today and I fear it will be a very long time before it opens again.

  100. For anyone with family and friends down in the Miami area.
    #BREAKING Miami-Dade to begin evacuations as early as Wed., ahead of #Irma, county offices to close Thur., Fri.

    1. Indeed it does. I wonder if this means that the GFS solution is a little closer
      to reality than the Euro was???

      Time will tell.

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