Wednesday Forecast


No big changes today. I’m aware of the model antics regarding the system formerly known as Invest 99L and currently known as Tropical Depression 9, and probably soon to be known as a tropical storm. I’ll keep an eye on it. First, a slow-moving cold front approaches today and passes through slowly on Thursday, followed by a cooler air mass and a little instability on Friday before high pressure takes over Saturday and probably holds through Sunday.
TODAY: Partly sunny. Isolated showers/thunderstorms late. Highs 77-88, coolest Cape Cod. Wind SW 5-15 MPH.
TONIGHT: Variably cloudy. Isolated to scattered showers/thunderstorms. Lows 60-68. Wind SW 5-15 MPH.
THURSDAY: Mostly cloudy. Chance of showers. Highs 73-80. Wind variable 5-15 MPH.
FRIDAY: Mostly sunny. Breezy. Lows 52-60. Highs 73-80.
SATURDAY: Mostly sunny. Breezy. Lows 48-56. Highs 75-82.
SUNDAY: Partly sunny. Lows 55-62. Highs 77-85.

DAYS 6-10 (SEPTEMBER 5-9)…
Staying with a dry forecast for Labor Day September 5 but keeping an eye on the tropical system. Isolated showers/thunderstorms possible September 6. Fair September 7-9. Temperatures mainly above normal.
Remainder of Labor Day Weekend September 4-5 looks dry with a warm-up. Isolated showers/thunderstorms possible September 6 with a cold front then fair and drier September 7-8.

DAYS 11-15 (SEPTEMBER 10-14)…
Dry pattern dominates. Temperatures above normal.

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205 Responses to Wednesday Forecast

  1. Tom says:

    Thanks TK !

  2. Vicki says:

    Thank you TK

    So you do not expect any problems on the cape Sunday?

    Lots of people have plans this weekend. As hard as it is, Hoping the general idea gets out there in time to work on plan B

  3. North says:

    Thanks TK. 06GFS was interesting with its double hit :).

  4. JpDave says:

    Good morning TK and thanks for the update.

    Not sure what to think of TD9.

    Just based on our drought alone would leave one to believe it WILL be a miss.
    But then again, anything “could” happen. I am leaning towards a miss, despite what
    the GFS and the CMC say. The Euro backed off on the left turn considerably. It’s still
    there but not nearly as pronounced and does not move as much Westward, basically
    causing a miss.

    So we shall see.

  5. Sue says:

    Thank you TK!

  6. JimmyJames says:

    Thanks TK.
    This tweet from meteorologist Ed Vallee at AccuWeather.
    Numerous members of Euro EPS are trying to “re-curve” #TD9 into Northeast. High uncertainty, but must be monitored.

    Here is something else we need to watch with regards to TD 9 from NYNJPA weather
    The short wave diving through the Northern Plains right now is what we need to watch for.

    If a part of the vorticity max brakes off & drops into the Tennessee River Valley, then TD9 develops into is tracking along the coast.

    HOWEVER, if the short wave stays over the Great Lakes and Canada, then TD9 just exits into the Atlantic Ocean.

    • JpDave says:

      Short wave, short wave, who has the short wave.

      Just for fun, here is some decent information on “short waves” so we are
      clear on what is meant by this tweet: ( Click On the embedded links as well.)



      A shortwave trough can be defined in several ways. The following are characteristics that most shortwave troughs possess:

      (1) Shortwaves are smaller than longwave troughs
      (2) Shortwaves have a counterclockwise kink to the height contours
      (3) They are associated with an upper level front or a cold pool aloft
      (4) Shortwaves generate positive curvature vorticity and positive shear vorticity
      (5) Shortwaves often represent baroclinicity in the troposphere (WAA and CAA)
      (6) Shortwaves are imbedded within the longwave trough / ridge pattern
      (7) Shortwaves are best located on the 700 and 500 mb chart / prog
      (8) Rising motion occurs within the exit sector of a shortwave
      (9) Their size and influence ranges from the mesoscale to the synoptic scale
      (10) Shortwaves move faster than longwaves (usually more than twice as fast).

      The link below has examples of shortwave troughs.

  7. MassBay says:

    Thank you.

  8. JimmyJames says:

    Posting the link to meteorologist John Homenuk twitter page and you could see with the GEFS the ensembles members are near the coast others over the ocean if you scroll down. I feel like were tracking a Noreaster here will all the different solutions. Nice pic to go with this tweet.
    Story of two model runs. Earlier GFS gave TD9 escape route east. New runs force it toward Northeast US. We will see.

  9. JimmyJames says:

    Ryan Hanrahan communicates with this guy so I figured he is good. If I see some twitter chatter will post. I always like hearing different perspectives.
    My gut says fish storm.

  10. JimmyJames says:

    That is too close for comfort.
    TD 9 does look healthy this morning.

  11. JimmyJames says:

    Based on that I would be surprised if we don’t have Hermine at 11am.

  12. JimmyJames says:

    Makes me hungry every time I look at those spaghetti plots.

  13. Captain Fantastic says:

    Wednesday is Prince spaghetti day.

  14. JpDave says:

    12Z NAM is interesting. Not sure what impact it would have for us just yet,
    BUT the NAM takes the system into the Pan Handle of Florida and across Southeast
    Georgia and then South Carolina. Looks like it would emerge on the coast of
    Northern SC or Se North Carolina, if not even staying inland longer????

    Here it is at 60 hours

    We know that the NAM is not particularly good with hurricanes, but interesting

    • JpDave says:

      WOW! It has it staying inland, but dropping so much rain, it appears
      to be maintaining intensity while over land. Interesting.

      Most models don’t have this track. I find it extremely fascinating that NAM
      chooses to do so. 😀

      • JpDave says:

        It’s remaining INLAND the whole way up the coast and looking
        at the 250 mb chart, looks to get up here and perhaps WEST
        of the coastal plain. Perhaps well west like up the Hudson????

        • Mark says:

          NAM tends to do this in the winter as well with coastal storms. Tends to be more amped and further N/W with storm tracks than most other guidance.

          • JpDave says:

            True, but this is quite an outlier now. Of course
            we don’t know how the other 12Z guidance looks yet.

            None-the-less, it’s getting interesting.

  15. Woods Hill Weather says:

    While the models are busy playing with a shortwave regarding several days from now, TD 9 has quietly become stationary.

  16. Tj says:

    What’s system are we talking about now? TD9 in the gulf or off SC coast? Thanks TJ

  17. JimmyJames says:

    New Cone of uncertainty
    All of SNE in it exception being western parts of MA and far northwest CT

  18. JimmyJames says:

    This was a tweet yesterday from Ryan Hanrahan I found interesting
    Slower landfall in FL increases odds of blocking ridge building over Canadian Maritimes closing “escape hatch” and a stall off Mid Atlantic.

  19. AceMaster says:

    Excellent live video feed from Barry Burbank on facebook re: potential tropical system here

  20. AceMaster says:

    Barry voiced his concern for strengthening potential as it meanders south of us once it gets over open waters off the Carolinas. Not many models have this more than an extratropical depression up here but there is potential

  21. JpDave says:


    The 12Z GFS takes TD9 on a very similar track as the NAM at least through hour 63.

    • JpDave says:

      Seems to have a digging 200mb trough. If it tightens up enough, that baby is coming up here. We shall see.

      • JpDave says:

        Could still exit stage right. Several more frames to go before
        we know. Just don’t know how much that trough digs. If it doesn’t, then there remains an escape route to the East.

  22. SAK says:

    New GFS is WAAAAAAAAAAAAY west of the previous run.

  23. JimmyJames says:

    Once it makes landfall in Florida center stays over land through hour 84.

  24. Woods Hill Weather says:

    So it was touched upon above but the system milling around in the gulf just a dozen hours longer changes everything, because the mid latitudes don’t wait for the tropical to make up its mind. They just keep right on moving so that the setup is different by the time it gets involved.

    • JpDave says:

      TK, it looks like that drastic last minute turn to the Left corrected itself,
      but look how it resolved itself. Not sure which is worse.

  25. JpDave says:

    This would certainly WIPE out many people’s Labor Day plans.

  26. Vicki says:

    TK – just saw your comment re having backup plan. Thank you. Most do have one but unfortunately, as I believe SAK said, it is never a good thing when a good sized storm is around the ocean areas on a major weekend. Judging from what I am reading above, the timing stinks. I am hoping there is enough of a handle on this that the weather folks can get the word out in time…more than they did with Eduardo for instance and even Irene and Earl. I figure we are lucky here because we see the give and take and reasoning. The average person doesn’t have that. Although, in my silly opinion, they should all just be here.

  27. SAK says:

    New Canadian also takes the inland route up before emerging offshore again near Atlantic City through Hour 108.

  28. JimmyJames says:

    If stays over land it will be a rain event for the areas it affects.

    • Vicki says:

      Thank you, JJ. And if it does emerge off NJ coast, it would be in too weak a state to develop into a hurricane. But would it be able to develop into a TS.

      I know this is all what ifs. I’m just curious about how any system would work under that scenario.

      • AceMaster says:

        Even though the water temps are above normal at that latitude, they are not warm enough to cause rapid intensification, or much intensification for that matter.

        • JpDave says:

          About the only thing the water there “might” be sufficient for is “Maintaining” strength of an approaching Tropical
          system OR at least have it NOT be diminishing quickly.

          • AceMaster says:

            True, but if the newest data is correct, this thing will be over land for a long time, losing most if not all its tropical characteristics.

            • JpDave says:

              Agree 100%. As depicted, it would be
              mostly an Extra-Tropical N’oreaster.
              How much wind depends on how intense
              it can get when it emerges off shore again.
              I’m thinking not so much. We shall see.

              I just want the RAIN!

              • AceMaster says:

                I’m with you on the rain. Sucks that it has to be during the holiday weekend, but its a small sacrifice.

      • AceMaster says:

        Usually, 82 degree water temp or higher to develop, intensify, and/or sustain a tropical cyclone.

        • JpDave says:

          It is my understanding that the magic number is 80 degrees. If It’s coming up here and the water is 77
          it’s not going to destroy it. It will maintain or at least
          weaken very slowly.

          Now, if it hits 60 degree water, then it weakens rather rapidly.

  29. JimmyJames says:

    The longer it spends over land the less likely it will become anything tropical when and if it emerges back in my opinion. More likely it will be like a Noreaster in the winter.

  30. JpDave says:

    The 12Z UKMET brings it up here as well, although Just a tad off shore.

    The 12Z Hurricane models are Different.

    The HWRF still takes it well off shore, while the GFDL brings it up, but turns right
    just South of New England. Would probably get into the rain shield, but miss the brunt of it.

    Next up, the Euro. 😀

  31. JimmyJames says:

    Looking at the pressure of some of the 12z model runs there not projecting a deep low pressure. We have seen more intense Noreaster’s than what is being projected.

  32. AceMaster says:

    TD9 is starting to get that “look.” Wouldn’t surprise me if we had Hermine soon

  33. JimmyJames says:

    Posting link to Eric Fisher page which shows image of GEFS ensembles. The ensemble mean looks south of Long Island where the operation run takes an inland route.

  34. AceMaster says:

    I’d almost prefer this be a tropical system when it gets up here, at least the strongest winds would be on the east side away from us. If it becomes sub or extra tropical, the wind field will expand. With the poor health of many trees in the drought areas, we could see tree damage from even minimal winds.

  35. Tom says:

    2 thoughts ….

    Looking at the satellite picture, I think the mid level and surface circulation may be getting more closely aligned. I’m quite interested for the next recon plane’s pressure that they find.

    A tropical system doesn’t have to have a low pressure to cause havoc. Only need to look back a few weeks to Louisiana and what was an unnamed tropical system. Certainly, the atmosphere that system had to work with was more loaded with moisture than the one that will be in place along the east coast.

    As everyone else is …. looking forward to the EURO. :)

  36. Tj says:

    Would I be mistaken if I said this looks like a fairly large tropical depression?

  37. JimmyJames says:

    We finally have Hermine!!!

  38. SAK says:

    TD 9 is now TS Hermine. Officially 40 mph winds, but recon keeps consistently finding 50 mph surface winds.

  39. WxWatcher says:

    Another name change; TD 9 has become “Hermine”.

  40. AceMaster says:

    That was a looooooong labor for Hermine :)

  41. JpDave says:

    Euro Also has Hermine making Landfall on the FL Panhandle, just about the same
    location as the NAM and the GFS. Will it also take the inland route? We’ll need about 1/2 hour to know.

  42. JimmyJames says:

    We look to have agreement here so far with this run of 12z EURO.

  43. WxWatcher says:

    ECMWF decides it’s gonna one-up the rest of the 12z guidance.

  44. JimmyJames says:

    It emerges offshore east of south Jersey 993 mb low but stays over land for a long time.

  45. Tom says:

    Oh boy ….. Do the warm 850mb temps right under the center at hr 96 mean it’s mostly still a warm core system ? It intensified from the Carolinas to NJ !

  46. JimmyJames says:

    This tweet from Ryan Hanrahan
    ECMWF brings Hermine up this way. Impact would be like a strong (rainy) nor’easter.

  47. JimmyJames says:

    To me and just my opinion it stays too long over the land and when it emerges offshore with that run of 12z EURO I don’t see how it regains strength to be a tropical system.

    • AceMaster says:

      Depends on where it emerges. Off the Carolinas and it could strengthen. Jersey shore? Nope. Also depends on forward speed. The slower it moves from wherever it emerges the better chance of regaining at least some tropical characteristics.

  48. AceMaster says:

    What day of the weekend would be most impacted by these scenarios? Sunday?

  49. JpDave says:

    Euro has it coming off shore at the NC/VA border between hours 78 and 84.
    Then it is over water the rest of the way.

  50. JpDave says:

    HOLD the presses.

    At 120 hours, EURO does an about face and the thing moves Southeastward.

    96 hours

    120 hours\


  51. JimmyJames says:

    I just noticed that.
    Not good for the folks in southern NJ with that EURO run.

  52. JpDave says:

    From hour 96 to hour 108, it actually moves Southwestward!!!

  53. JimmyJames says:

    Like it ran into a brick wall and can’t penetrate further north.

    • Tom says:

      Yup, building 500 mb ridge right into the Maritimes ….. 588dm contour nosing up through central Nova Scotia, not going to move through that. :)

  54. North says:

    I am in the GFS camp and staying there on this one. Was first to start seeing this possible impact from the start and has been ok with this system all along in not strengthening it at the start either. Location may not end up being good on these early runs but when is it ever 5 days out with a tropical system. Just my thoughts on not reading too much into the EURO solution.

  55. JpDave says:

    At 192 hours, it is back on the North Carolina Coast.

    Classic Loopty loop

  56. JpDave says:

    Who said the 12Z Euro was one-Upping the rest of the guidance????
    WxWatcher? Good call!

    • Woods Hill Weather says:

      That doesn’t mean it’s the correct solution. It’s just a different solution.

      How many different solutions has the European model had with this system now? :)

      • JpDave says:

        Of course. That is understood.

        It did offer some entertainment value for sure.

        Now what’s it gonna be?

        Seems like most everything is on the table.

        • Woods Hill Weather says:

          Tropical systems often do this. Add weak or changing steering currents and you just have to basically… “go with the flow”. 😛

          • JpDave says:

            In this case, it might be “flow with the go”.

            I can’t wait to see exactly what really happens.

  57. JpDave says:

    At 240 hours, it ends up back in our neck of the woods as a 980 mb
    System. How much tropical and how much extra tropical, I don’t know.

  58. JpDave says:

    Well, that was entertaining. Back to work.

  59. JpDave says:

    I leave you with this final chart on Hermine. 12Z Euro at 240 hours.
    10M Wind gust chart in MPH. This is the strongest since making landfall in Florida.

  60. AceMaster says:

    The euro is drunk. But, that’s what we all said before Sandy

  61. Amy says:

    At what point in time would forecasts on Hermine’s direction and strength start to have some confidence behind them? Thinking in terms of when to hop in the sailboat and start heading north out of Buzzards Bay. We were hoping to get a second visit to Martha’s Vineyard in this weekeend… we are often thwarted by the weather on this…

    • JpDave says:

      Too important for me to weigh in with a take on this.
      I’d wait for a response from TK and/or SAK.

      Good luck

    • Woods Hill Weather says:

      48 hours is a decent guess right now. Given the potential interaction, I’m going to guess that lead-time confidence is below normal throughout.

  62. Joshua says:

    Amy, even if the storm does not hit the islands Sunday/Monday, my initial guess is that there may be significant wave formations from a large ocean storm spinning well off the coast. The waves may be particularly large east and southeast of Outer Cape. But, I’m not an expert on these matters.

    • JpDave says:

      You may be 100% correct Joshua.

    • Vicki says:

      That brings a question to mind. If waves are already increased from Gaston and Hermine comes on top of him, will they be even more pronounced. Or will there be sufficient time between the two?

      • JpDave says:

        You are forgetting that TD 8 has been milling around as well.
        I would like it would add to it.

  63. JpDave says:

    At this point, I do NOT want to see any rain until at least 1 second after MidNight.
    It’s 8/31 already, what’s a few more hours. Since we’ve come this far, let’s make
    this the direst Summer since records were kept in Boston (does not mean driest ever).
    But still, that is something. I wouldn’t want it ruined by .05 or .07 inch before
    Mid Night. There are some light showers roaming about out there.

  64. JpDave says:

    Sox are ahead 6-4. Let’s see how they blow this one?

    Farrell, I’m counting on you.

    • AceMaster says:

      He came through for you! All tied up. The 8th inning has doomed the sox the 2nd half of the year so far.

      • JpDave says:

        I was actually hoping for some reverse psychology here. I guess it
        back fired. 😀 😀 😀

        KISS this one good-bye

  65. JpDave says:

    How about a 12Z GFS surface and precip Loop courtesy of College Of DuPage Weather.

    And a Euro loop. Unforunately, with COD it only goes to 168 hours.

  66. Woods Hill Weather says:

    Wave interaction is very complex, but we won’t have triple the wave height or triple the wave power because there are 3 storms out there. Just plan on rough surf and rip current risks for a while, as is the case when the tropics are on the active side. :)

    • JpDave says:

      Agree, I didn’t mean to imply that it would be triple the wave height, just
      that it would add to the already roughness of the ocean.

      Not going to be mirror calm out there, that’s for sure. 😀

  67. JpDave says:

    18Z NAM’s track is farther to the EAST. Surprise, surprise.
    AND it is about 10mb weaker than the 12Z run.

  68. Philip says:

    What is the latest timeframe for Hermine’s effects? Can it hold off until Monday?

  69. Joshua says:

    Sox make it interesting. Horrific bullpen. Not a recipe for success in the post-season, but they might just get into the dance. Anything can happen at that point.

  70. I think the weekend will be uneventful

  71. WxWatcher says:

    Here’s an interesting look at the observations from the recon plane that has been flying through Hermine. The wind barbs are flight level winds. The orange dots with corresponding pressure values represent center fixes. The interesting thing here is that Hermine’s center, or at least its dominant center, has relocated southeast of the original center this evening. The two 1004mb points are actually the first two fixes; the two 1002mb points are the latter two. Overall, still not a well organized cyclone, but it is strengthening.

  72. Tom says:

    Discussion from Wilmington, NC NWS office. Under the short term, the paragraph about the storm’s potential to maintain strength while over land and the reasons why was most interesting.

  73. Tom says:

    Tampa, points south along the Florida Gulf coast getting pummeled with rain.

    • JPDave says:

      Again, tons of rain out ahead of system. Almost as if over water while passing over the water logged land. 😀

  74. Joshua says:

    I think we break the record for the driest summer on the books (not ever, of course, but still). The rain to our west and south may not even make it here, and if it does it won’t be before midnight. Amazing. Just last year we broke the record for the most snow in one season. Now we break the record for the driest summer.

  75. bostbliz says:

    Something that interests me is that big high over eastern Canada. If that storm ever gets up here, it will have nowhere to go and may end up stalling for a bit.

  76. JPDave says:

    Raining here a bit. Does not look impressive on radar. I think we make this
    the driest Summer since records were kept at Boston.

    We shall see. My rain gauge has not tripped yet. Trips at 0.01 inch.

  77. JimmyJames says:

    0z CMC similar to 0z GFS with what is ever left Hermine comes back over the water east of Cape Hatteras, NC comes up does a bit of turn back to the left turn then moves back east staying south of us.
    CMC closest pass to SNE

  78. Woods Hill Weather says:

    Nice little late-night t-storms across part of southern MA. A decent amount of CG lightning as of 1:50AM.

  79. Tom says:

    Recon plane :

    Pressure : 994 mb

  80. Coastal says:

    Believe much stronger Euro over very warm water off MA coast. 28C. euro 976 mb there. No matter what status, should be stronger there

  81. Tom says:

    I think the jet stream interaction has begun and is starting to help this thing breathe better. I believe its showing itself on the storm’s northern cloud shield with that expanding and fanning out of the cloud cover.

    Last pressure was down to 994 mb and the max flight level wind encountered was 66 knots.

    It isn’t the traditional symmetric looking storm, but I wouldn’t be surprise if we’re going to see a further pressure drop this morning somewhere into the 980’s and a rise of the corresponding sustained winds.

  82. Woods Hill Weather says:

    New post!