Thursday, August 29, 2019

Dorian

9-9 - Finally have time for a wrap up.
Once Dorian became mobile, it started the process of restrengthening and regained major hurricane status briefly before making landfall on Cape Hatteras as I think a cat one.  
It cruised east of JAX at about 6kts.
Moved along the coast past Charleston
Almost hits Cape Fear
Looks like it hits Cape Lookout, but not officially landfall until OBX

The eye went over a "buoy"  - Hatteras Station



By sunset it was moving off the coast, restrengthening again.


But Dorian wasn't done. As it headed to Nova Scotia, it caused TS force winds along the MD, DE, NJ, NY, MA and RI coasts.
 


9-3  Morning - eyewall currently having issues and open to the SW.  If this continues, it will not gain strength once it escapes its current environment.  Then it will encounter some shear until it heads NE.

NAM is the only model without a landfall, or at least that the center doesn't clear some land.

Otherwise the strike zone is N Myrtle Beach to Cape Lookout.  I'd go with Cape Fear right now.
HWRF skips right over the three capes.

GFS is right off Myrtle Beach and hits Cape Fear - takes on CL and CH too.
NAM 3k isn't far enough out, but looks further west than its parent NAM and will hit Cape Fear
Euro keeps the core barely off the coast at MB but hits CF, CL and CH.  Like the NAM, its unclear if the actual center crosses, though the Euro is a little closer in than the NAM.  The 0z run is similar hitting CL.

Point of all this is that there is little variability in the models.  In the big picture, the track is set.  Its just minor details that matter.  If it comes inland earlier, does it stay inland and decline.  If it stays off the coast does it hold strength or increase?   Below is the gust map from the Euro - just a 30 mile shift can cause much more or much less pain.



9-2 Afternoon

Dorian still over Grand Bahama, devastating it. Videos from there heartbreaking.
Dorian underwent an eye wall replacement and used up a lot of the warm water at the surface, so its declining now.  Unsure if it will ramp back up, but as it weakens, the wind field spreads.


The damage is extensive and ongoing.  Links to videos below.

 https://twitter.com/MorrisMedici/status/1168570843754049538


 https://twitter.com/julmisjames/status/1168540891583307780


9-2  Morning

Not much has changed with the track and the fear of it moving west past Grand Bahama has abated. Now it will sit for a while before lifting either N or NW.


Whether the eye crosses land in FL is questionable and I still have no prediction.  I'm leaning no though.  GFS has hurricane winds along the coast though, which warrant monitoring.  All models have it coming really close to Cape Canaveral, then hugging the coast all the way to Cape Hatteras.  Definitive landfall looks likely from Myrtle Beach north to Hatteras, but the entire coast to OBX is subject to hurricane force winds, either sustained or gusts, along with storm surge.

Euro 6z upped the gusts along FL coast.  As you can see in the map, a few miles makes a difference. Gusts of 107kts or 120mph on Canaveral.
Precip looks again the worst along the immediate coast were a few miles makes a difference.  Once it gets in to the NC area, it should be more inland as the storm weakens and expands.




Late afternoon. 
A look at the 5 main deterministic model runs from this afternoon.  No they are not the same.  Some do have hits grazing either FL or the Carolinas.  But the consensus is astonishing as is that its now in line with climatology. 






8-30 Early afternoon update.

Back to 50/50 on landfall in FL.  May be SC/NC instead.  What is incredible is this run by the Euro that ultimately hits Nova Scotia.

 Much like Matthew, but Matthew was already going north when it got to FL.

Very impressive on the satellite


8-30   Morning update.

A little more confident of a Florida strike, leaning 65/35 now.  Will also have to start paying attention to its remnants for the Mid Atlantic through Maine/NS

Wind map says it all track wise.  Euro and GFS
Euro

GFS
 Dorian continues to intensify and borders a major hurricane as of 8am (3mph away from Cat 3, with some obs over 110mph not being counted).  Its also slow enough that the the upper level features that we think may guide it, may not.  But, it doesn't appear at this time that the Keys are any longer in play.  Miami to Daytona is my broad guess.  West Palm to Cocoa Beach is a more narrow guess.  NHC predicts 140mph at landfall now...I'm going to go with 115mph. 

8-29  Its been awhile...

Dorian shocked the weather world by not only missing Hispaniola but pretty much glancing or missing Puerto Rico as well.  Today its moving kinda slowly away, not gaining too much strength as some dry air, a touch of shear and proximity to Hispaniola/PR is still having an affect on its flow.

Dorian is full of surprises.  Here is  the 8am advisory having it hit DR.

And here is the advisory for 11am the next day, pretty much as its hiting the USVI
That's quite a surprise.

I ran a history of tropical cyclones that went through the area that Dorian was in this morning.  Historically speaking, its rare that a 'cane hits Florida from this position, traveling in this direction.  Its even more rare for a 'cane to be in this spot after hitting Barbados. There's one storm that's highlighted, and it killed 51 people.

So historically, storms have curved away from Florida - typically this is due to a well timed front/trough.  Like the one that is going through the EC today.  If Dorian were at that X, it would likely curve out to sea.  But its not.

One small feature that pops up is a tiny upper low to its west.  You can barely make it out on the water vapor loop earlier today, just north of Turks and Caicos.
That ULL (upper level low) heads west, and Dorian is expected to follow it as a ridge builds in after the passing of the trough as depicted on the Euro for sake of ease. You can also see the ridge above it until the last 2 frames...that's where it gets interesting.
Right around 84-96 hours, the ridge begins to breakdown. Earlier on the GFS, later on the latest HMON.  You can also see the distance between the ULL and the storm increases so its influence is lost, and a ridge should technically be between the two by hour 96.  This leaves Dorian without any steering.  Thus, you have solutions all over the place.
Again the Euro stalls it and moves it up the coast, not terribly windy, but slow and rainy.

Or the GFS and CMC which bring it directly into FL and THEN swing it up.

Or the HMON, which takes it down to the Keys as a really bad major storm.
Or you can look at the HWRF (the other US hurricane model) which has it hitting Cocoa Beach (no real loss there) with 115-120mph winds.
Last option is the NAVGEM which curves it back out before hitting FL.  The Carolina's aren't safe with this solution though.
So to wrap it all up - if you think they know where landfall will be, you're crazy.
I'm at 50/50 if it hits Florida vs curving out, just based on climatology and there's that strong ridge.  While I doubt the Keys are really in play, Miami to Jax is.  Sorry, can't pin it down more at this point.


Storm 3 - could be the one! (spoiler, it was)

 2/9  Set up is an upper low over TX that heads northeast into TN valley and then transfers off the coast. At the upper levels, there's ...