ATL: DORIAN - Post-Tropical - Discussion

[got ants?]

Is that convection being drawn off Hispanola and Cuba?

It also looks like outflow pushing west just a bit...

Not enough time to get its act together before coming my way (Hollywood FL) but it could be of concern to my greenhouses..

[Hurricane Alexis]

Dry air is no longer an issue and shear is in the range of 10-20 knots. Not super conducive but unless my eyes are deceiving me it looks like shear will be dropping. My rule of thumb is to never ever write anything off down there that is still popping convection. Especially since its closer to land now. I do not like surprises.

I am still not 100 percent sure that this flare up is not nocturnally driven and I wont be sure until we have several hours of daylight down there. If it is still flaring up this afternoon then chances of redevelopment will go up a notch,

It probably is nocturnal but I'm no met. You're right about the environment getting more favorable. Shear has been dropping for a while now.

[HURAKAN]

the trough remains strong and the divergence aloft is helping to generate the convection, which then promptly collapses

[jlauderdal]

Dry air is no longer an issue and shear is in the range of 10-20 knots. Not super conducive but unless my eyes are deceiving me it looks like shear will be dropping. My rule of thumb is to never ever write anything off down there that is still popping convection. Especially since its closer to land now. I do not like surprises.

I am still not 100 percent sure that this flare up is not nocturnally driven and I wont be sure until we have several hours of daylight down there. If it is still flaring up this afternoon then chances of redevelopment will go up a notch,

It probably is nocturnal but I'm no met. You're right about the environment getting more favorable. Shear has been dropping for a while now.

anything from levi cowan on what this thing might do?

[GCANE]

Small convection at 22N 72.5W maybe an indication that the ULL is weakening.

http://www.ssd.noaa.gov/PS/TROP/floater ... -long.html

[Thunder44]

Small convection at 22N 72.5W maybe an indication that the ULL is weakening.

http://www.ssd.noaa.gov/PS/TROP/floater ... -long.html

It's entrained with the ULL now. There's also no evidence of closed LLC, based on surface obs.

[Siker]

Remains at 20%.

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A TROUGH OF LOW PRESSURE...THE REMNANTS OF DORIAN...IS PRODUCING
DISORGANIZED SHOWERS AND THUNDERSTORMS THAT EXTENDS A FEW HUNDRED
MILES EAST AND NORTHEAST OF THE TURKS AND CAICOS ISLANDS. UPPER-
LEVEL WINDS ARE NOT EXPECTED TO BE CONDUCIVE FOR REGENERATION
DURING THE NEXT COUPLE OF DAYS AS THE DISTURBANCE MOVES WESTWARD TO
WEST-NORTHWESTWARD AT 10 TO 15 MPH. THIS SYSTEM HAS A LOW
CHANCE...20 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS. SHOWERS AND GUSTY WINDS IN SQUALLS ARE SPREADING
ACROSS THE TURKS AND CAICOS ISLANDS AND SHOULD BEGIN TO MOVE
WESTWARD ACROSS PORTIONS OF THE BAHAMAS BY THIS AFTERNOON INTO
EARLY THURSDAY.

[jhpigott]

wave axis appears to be around 21.5N 71W?

http://rammb.cira.colostate.edu/ramsdis ... height=480

[wxman57]

By the way, surface pressure reports in that area of squalls indicate 1020-1021mb. No low pressure there. There's very little evidence left of the wave, but the TPW loop indicates it is near 74W this morning.

http://tropic.ssec.wisc.edu/real-time/m ... /main.html

[Blown Away]

06z Guidance
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
0604 UTC TUE JUL 30 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 DORIAN (AL912013) 20130730 0600 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
130730 0600 130730 1800 130731 0600 130731 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 21.4N 69.4W 22.1N 72.0W 22.6N 74.6W 23.1N 76.9W
BAMD 21.4N 69.4W 21.8N 71.1W 21.9N 72.7W 22.1N 74.3W
BAMM 21.4N 69.4W 21.8N 71.6W 21.9N 73.5W 22.1N 75.4W
LBAR 21.4N 69.4W 21.8N 71.5W 22.2N 73.4W 22.6N 75.5W
SHIP 25KTS 27KTS 30KTS 35KTS
DSHP 25KTS 27KTS 30KTS 35KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
130801 0600 130802 0600 130803 0600 130804 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 23.7N 79.0W 25.1N 81.4W 26.2N 83.2W 27.3N 84.6W
BAMD 22.4N 75.9W 23.5N 78.5W 24.9N 80.9W 25.4N 83.4W
BAMM 22.4N 77.1W 23.7N 79.5W 25.3N 81.5W 26.5N 83.0W
LBAR 23.2N 77.5W 25.3N 80.5W 28.1N 81.4W 29.9N 80.1W
SHIP 39KTS 54KTS 66KTS 70KTS
DSHP 39KTS 54KTS 66KTS 70KTS

...INITIAL CONDITIONS...
LATCUR = 21.4N LONCUR = 69.4W DIRCUR = 280DEG SPDCUR = 13KT
LATM12 = 21.0N LONM12 = 66.8W DIRM12 = 279DEG SPDM12 = 13KT
LATM24 = 20.6N LONM24 = 63.7W
WNDCUR = 25KT RMAXWD = 60NM WNDM12 = 25KT
CENPRS = 1015MB OUTPRS = 1017MB OUTRAD = 90NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

[wzrgirl1]

Can someone explain this to me? If this only has a 20% chance of redevelopment then why are the intensity forecasts so high? Are these only valid if there is a closed low?

06z Guidance
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
0604 UTC TUE JUL 30 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 DORIAN (AL912013) 20130730 0600 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
130730 0600 130730 1800 130731 0600 130731 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 21.4N 69.4W 22.1N 72.0W 22.6N 74.6W 23.1N 76.9W
BAMD 21.4N 69.4W 21.8N 71.1W 21.9N 72.7W 22.1N 74.3W
BAMM 21.4N 69.4W 21.8N 71.6W 21.9N 73.5W 22.1N 75.4W
LBAR 21.4N 69.4W 21.8N 71.5W 22.2N 73.4W 22.6N 75.5W
SHIP 25KTS 27KTS 30KTS 35KTS
DSHP 25KTS 27KTS 30KTS 35KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
130801 0600 130802 0600 130803 0600 130804 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 23.7N 79.0W 25.1N 81.4W 26.2N 83.2W 27.3N 84.6W
BAMD 22.4N 75.9W 23.5N 78.5W 24.9N 80.9W 25.4N 83.4W
BAMM 22.4N 77.1W 23.7N 79.5W 25.3N 81.5W 26.5N 83.0W
LBAR 23.2N 77.5W 25.3N 80.5W 28.1N 81.4W 29.9N 80.1W
SHIP 39KTS 54KTS 66KTS 70KTS
DSHP 39KTS 54KTS 66KTS 70KTS

...INITIAL CONDITIONS...
LATCUR = 21.4N LONCUR = 69.4W DIRCUR = 280DEG SPDCUR = 13KT
LATM12 = 21.0N LONM12 = 66.8W DIRM12 = 279DEG SPDM12 = 13KT
LATM24 = 20.6N LONM24 = 63.7W
WNDCUR = 25KT RMAXWD = 60NM WNDM12 = 25KT
CENPRS = 1015MB OUTPRS = 1017MB OUTRAD = 90NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

[Alyono]

yes.. SHIPS/LGE are only valid if there is a closed low

[wzrgirl1]

So why run the models then?

yes.. SHIPS/LGE are only valid if there is a closed low

[blp]

The ULL still looks in control and I don't think it will weaken enough to allow for development. We must be grateful for that ULL because considering the tenacity of this system it would have surely redeveloped in the warm waters it is over now.

http://www.ssd.noaa.gov/goes/east/tatl/wv-animated.gif

[ronjon]

Actually the statistical models show more skill than the dynamical models at intensity according to a paper by Rappaport and others (2009). The SHIPS model does incorporate shear predictions from the GFS.

[tolakram]

Actually the statistical models show more skill than the dynamical models at intensity according to a paper by Rappaport and others (2009). The SHIPS model does incorporate shear predictions from the GFS.

With or without a closed low?

[Alyono]

So why run the models then?

yes.. SHIPS/LGE are only valid if there is a closed low

to be used as general guidance when there is not a closed low

[NDG]

The GFS won by the way. the euro was forecasting for the ULL to move out of the way and or weaken and for Dorian to find better upper level conditions, is not happening. Just like the GFS was indicating Dorian's vorticity keeps falling apart, may it rest in peace.

[wxman57]

Nothing left of Dorian now. Can't find a wave axis. Thunderstorms SE of the upper low are not related to Dorian. Now, let's enjoy the next 2 weeks of no activity (according to the GFS).

[Steve H.]

Well, I think I can see what's left of the old surface circulation, a tiny spin moving over the far SE Bahama islands, quite discombobulated.