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Friday, October 2, 2015

Negative tilted trough, storm out to sea?


NAM, Canadian, and NAVGEM are only operational models left with a US coastal hit.  Some hurricane ensemble members do as well, but they are in the minority.  So whats left to do but watch.  Some interesting features - there is a ULL in the Atlantic heading towards HJ, and an ULL over the SE heading to HJ.  There is also a negatively tilted trough at 250,300 and 500mb.  ULL lows at 850 and 750 have merged with HJ.  All of this, and it still goes out to sea.  

In the gif below, you can see the two upper level lows (swirls in orange/black)  mentioned above, you can see the water vapor stripping off HJ into the front/trough (that I thought would influence HJ).  You'd think that the two ULLs would either push the storm south, or squeeze it north along the jetstream and front.

Below are the winds at 300mb, which would steer the storm.  Black lines indicate direction of wind, red line is forecast track.  Makes no sense.  You'd think it would go north.

Thursday, October 1, 2015

Can the Euro snatch victory and save us all?

4:30  Euro holds out to sea again. GFS 6 and 12z agree.  UKMET hits Bermuda.  HWRF sends it out to sea.  GFDL, CMC, hurricane models and now the NAM are closer or hitting the east coast.   I still think a fast exit to the ENE from the Bahamas is odd - nothing really acting on the storm.  GFS is closer to my thinking, which means NYC-Cape should still watch this.  It would be horrible if the Euro changed its mind now! 

7:30 Monday's 12z run the Euro had the solution most models came to later yesterday - upper low snags Joaquin and it makes a hard left turn into the Carolinas.  Then Tuesday morning's run, Joaquin just headed towards Bermuda, only to move back to a position between Bermuda and the Cape on Wednesday.  No credit for strength, as it did predict 970 lows, it didn't get it into the 930's where it is (unofficially at this time) now.

Up until last night, every ( I mean every) other model had a US landfall, mostly between NC and NJ.  That is until the 0z GFS which shifted to the east/north to a NYC area landfall.  6z run of the GFS completely misses the US, might hit Canada.  UKMET also moved to a near Cape Cod solution on its 0z run. 

So we will see the forecasters likely shift the path east (already did somewhat this morning) as the trends are starting.  However, given the amount of time (now landfall on Monday/Tuesday) and that the deterministic models still aren't initializing and capturing the strength, plus some discrepancies in the upper levels and lastly, possible interaction with Ida, its hard to say we're past this one.  Still keep an eye on it.

Wednesday, September 30, 2015

Hurricane Joaquin

9-30 pm update.  Not too much change today, just a small shift west/south. Euro still showing it going out to sea.  GFDL still looks really bad, 939 mb with 130mph winds at landfall in NC.  Most models are focused on Outer Banks to Chesapeake now, with a few still showing NJ in the mix for a landfall.  What happens after landfall will need to be discussed at some point - models are all over on that one too.  My concern about the models is that none of them forecast a 105mph nearly cat 3 storm this early.  Typically you see stronger storms start to head north - Euro had kept it weaker, driving it further SW and slowing it so that it wasn't as influenced by the upper level low (ULL) over GA.  Its obviously way stronger than modeled, even at 12z today, but it hasn't affected any forecast yet.  Joaquin at this strength is still moving SW, which is odd for its strength but there are 200-300mb winds out of the NE which could be causing that (although it also could be outflow, and venting the system), but they aren't that strong.

18z GFDL

9-30  Euro did not change its mind, too much.  Just moved 150 miles or so to the west.  It remains the only model with no US landfall

6z GFDL currently leads in the worst case scenario with a westward moving storm with 120mph sustained winds just to the south of Chesapeake bay, which will already be backed up due to an easterly fetch. 
6z HWRF is only a little less concerning with a 945 low hitting the Outer Banks. Only 105mph winds

6z GFS very similar to HWRF (not usual) with 975 low hitting same area.  Tidbits has the winds at 100mph on its graphic.  0z is a little further north, same strength.

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 CMC goes 972mb low into the DelMarVa.
UKMET targets NJ

Overall spread of runs clearly in favor of a landfall