ATL: DORIAN - Post-Tropical - Discussion

[NDG]

Very interesting, a weak UL anticyclone has develop over 91L based on this latest analysis.

[cycloneye]

Intensity for 91L at 12z is up as time goes by. The full text is not out yet.

[wxman57]

SHIPS was forecasting steady intensification for the period when Dorian was steadily weakening to a tropical wave. It's a statistical model (the first "S" in SHIPS). Dynamic models all forecast weakening at that time. Redevelopment chances remain low.

[cycloneye]

[Evil Jeremy]

Very interesting, a weak UL anticyclone has develop over 91L based on this latest analysis.

http://tropic.ssec.wisc.edu/real-time/a ... g8shrZ.GIF

Kudos to ozonepete for calling it at 4am.

Convection still increasing. On the north side of the system, notice the cloud layers being streamed off to the north. Is this from shear?

http://img593.imageshack.us/img593/2766/o556.jpg

Not at all. The outflowing air at the tops of the very tall thunderstorms is blowing outward and away from them. When you see them feather at the tops like that it is often a sign that an upper level outflow mechanism is developing, i.e. an anti-cyclone is building over it.

[SFLcane]

interesting luis!

[cycloneye]

Dorian remnants should be watched in 3-5 days for redevelopment once north of PR near the Bahamas were it could slow to around 10kts near the Gulfstream.

You said this last evening and now it looks like maybe it will happen.

[NDG]

12z SHIPS brings this to a Cat 1 Hurricane off the coast of Miami.

Shear only moderate to low, it forecasts.

12 10 11 14 13 9 14 9 16 6 14 7 11

[HURAKAN]

If you see the shear graphic above and watch a loop of the remnants of Dorian, you notice that it's about to enter an area of higher shear. I don't see any surface circulation, so those thunderstorms will likely die down as they did yesterday.

[tailgater]

Where did the floater go?

Back up as 91L
RGB says the plane might find something
http://www.ssd.noaa.gov/PS/TROP/floater ... short.html

[SFLcane]

12z SHIPS brings this to a Cat 1 Hurricane off the coast of Miami.

Shear only moderate to low, it forecasts.

12 10 11 14 13 9 14 9 16 6 14 7 11

oh boy

[cycloneye]

This is a discussion made by Levi Cowan.

Well this is a little bit of a surprise to wake up to. Dorian is pulling inflow off the ocean to his south, something that was not happening 24 hours ago. This is a giveaway that whatever the pressures were like inside Dorian yesterday, they are lowering, causing air to accelerate inward towards the storm. The fact that convection is going off is a testament to the warmer water that Dorian is over and the upper divergence in front of the trough to the west. He still may get sheared to death, but if deep convection continues, the warm outflow aloft could bring his survival back on the table. I would almost bet that plane would find a weakly closed circulation right now.

[SFLcane]

[NDG]

Very light west winds started being reported at Burbuda. Prior to this it was very light northerly winds.

[NDG]

This is a discussion made by Levi Cowan.

Well this is a little bit of a surprise to wake up to. Dorian is pulling inflow off the ocean to his south, something that was not happening 24 hours ago. This is a giveaway that whatever the pressures were like inside Dorian yesterday, they are lowering, causing air to accelerate inward towards the storm. The fact that convection is going off is a testament to the warmer water that Dorian is over and the upper divergence in front of the trough to the west. He still may get sheared to death, but if deep convection continues, the warm outflow aloft could bring his survival back on the table. I would almost bet that plane would find a weakly closed circulation right now.

I totally agree with him.

[gatorcane]

If you see the shear graphic above and watch a loop of the remnants of Dorian, you notice that it's about to enter an area of higher shear. I don't see any surface circulation, so those thunderstorms will likely die down as they did yesterday.

That is what I think will happen also.

But as I posted Friday afternoon, I was not going to completely take my eye of this until completely dissipated because you just never know with these systems.

I thought this thing might have been done yesterday.

Hopefully this convection does die by the end-of-day. Conditions could be favorable in the Bahamas for this system as SHIPS is showing.

[cycloneye]

Here is the full text of 12z guidance for 91L. WOW!!

TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
1235 UTC SUN JUL 28 2013

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

ATLANTIC OBJECTIVE AIDS FOR

DISTURBANCE INVEST (AL912013) 20130728 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS... ...36 HRS...
130728 1200 130729 0000 130729 1200 130730 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 19.3N 59.5W 20.2N 62.7W 20.8N 65.8W 21.7N 68.9W
BAMD 19.3N 59.5W 20.2N 61.9W 21.1N 64.2W 21.9N 66.4W
BAMM 19.3N 59.5W 19.9N 62.3W 20.5N 65.0W 21.1N 67.6W
LBAR 19.3N 59.5W 20.1N 62.5W 20.7N 65.4W 21.2N 68.1W
SHIP 30KTS 35KTS 41KTS 46KTS
DSHP 30KTS 35KTS 41KTS 46KTS

...48 HRS... ...72 HRS... ...96 HRS... ..120 HRS...
130730 1200 130731 1200 130801 1200 130802 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 22.4N 71.9W 23.6N 77.4W 25.2N 81.0W 26.9N 81.9W
BAMD 22.5N 68.5W 23.4N 72.3W 24.6N 75.8W 26.8N 77.9W
BAMM 21.7N 70.2W 22.5N 74.6W 24.0N 78.3W 26.3N 80.0W
LBAR 21.4N 70.6W 21.7N 75.6W 23.5N 80.0W 28.0N 80.3W
SHIP 51KTS 59KTS 69KTS 78KTS
DSHP 51KTS 59KTS 69KTS 78KTS

...INITIAL CONDITIONS...
LATCUR = 19.3N LONCUR = 59.5W DIRCUR = 280DEG SPDCUR = 19KT
LATM12 = 18.6N LONM12 = 55.6W DIRM12 = 280DEG SPDM12 = 19KT
LATM24 = 18.4N LONM24 = 51.4W
WNDCUR = 30KT RMAXWD = 60NM WNDM12 = 30KT
CENPRS = 1012MB OUTPRS = 1016MB OUTRAD = 120NM SDEPTH = S
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

[HURAKAN]

Very light west winds started being reported at Burbuda. Prior to this it was very light northerly winds.

Antigua and Barbuda is reporting NE 3 mph.

http://weather.noaa.gov/weather/current/TAPA.html

[pgoss11]

Holy Cow!!

[HURAKAN]

What are the GFS and ECMWF saying? Yep, you can throw SHIPS away in this situation.