ATL: DORIAN - Post-Tropical - Discussion

[gatorcane]

Latest Floater frame shows convection popping up at 20.5N, 60.5W...(white circle at center of blob)

That is not where Recon is finding a low-level feature but that area sure looks suspicious to me!

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

[HURAKAN]

[gatorcane]

But couldn't a new surface feature be forming there and the one they are checking out 120NM further west is in the process of dissipating?

I would they they would want to check that area out.

pressures are the lowest where they found the surface feature.

It's there

Considering new convection is popping where the MLC is at 120NM further east, plus SAT imagery shows a nice cyclonic twist there, I would think they would fly over and check it out just to make sure nothing is starting to form at the surface.

[Dave]

000
URNT15 KNHC 281844
AF301 0104A DORIAN HDOB 17 20130728
183500 1933N 06247W 9775 00324 0143 +234 +225 010006 007 021 001 00
183530 1933N 06245W 9764 00340 0149 +234 +226 034005 007 021 002 03
183600 1933N 06243W 9770 00334 0148 +238 +214 039004 006 021 000 03
183630 1933N 06241W 9769 00334 0149 +234 +220 033005 005 019 000 00
183700 1933N 06240W 9772 00332 0149 +235 +215 045005 005 019 000 00
183730 1933N 06238W 9770 00334 0149 +235 +219 045006 006 019 000 00
183800 1932N 06236W 9773 00331 0148 +235 +216 054006 006 020 000 03
183830 1932N 06234W 9769 00334 0149 +234 +221 035006 007 021 000 00
183900 1932N 06232W 9770 00333 0150 +230 +228 047004 004 020 000 00
183930 1932N 06230W 9771 00333 0149 +230 +229 070004 005 019 000 00
184000 1932N 06228W 9772 00332 0148 +233 +227 082005 005 020 000 03
184030 1932N 06226W 9769 00334 0148 +235 +223 099004 005 019 000 03
184100 1932N 06225W 9772 00331 0147 +237 +216 148005 006 017 000 03
184130 1931N 06223W 9770 00330 0145 +241 +208 173006 007 017 001 03
184200 1931N 06221W 9769 00332 0145 +240 +211 176007 008 019 000 03
184230 1931N 06219W 9770 00331 0145 +237 +219 175005 007 017 001 03
184300 1931N 06217W 9773 00328 0145 +241 +212 191005 005 018 000 03
184330 1931N 06215W 9769 00332 0146 +239 +210 186005 005 019 000 03
184400 1931N 06213W 9770 00331 0146 +235 +218 185005 005 019 000 00
184430 1931N 06211W 9770 00331 0146 +231 +223 185006 007 015 000 00
$$
;

[chaser1]

I don't think there's an LLC yet either, but that's a mute point for the immediate. Point is that at minimum, this is a pretty dynamic wave that may well soon be in an environment of more conducive conditions. There is no question that Dorian has already experienced worse upper air and much drier air, then presently experiencing. Assuming no prior storm history with 91L, one would be hard pressed to not assume that at least slow development would likely continue to occur. The fact that the pressures are high and the appearing small size of any MLC, might lead me to consider that Dorian at some point have the "capacity" to deepen more rapidly, "if" and when a truly vertically state led low & mid level circulation align. I can see this starting to occur, but there other factors involved, and would guess might occur by midday tomm.

The fact that the "neutered" GFS is less effective in spotting cyclogenisis or that the Euro does not particularly well initialize them either is irrelevant to me. Of greater value might be those tools in determining near-mid term developmental & potential steering conditions.

[CrazyC83]

It looks like a partial circulation is trying to form, but unless there is one to the SE, there doesn't appear - at this time - to be a closed LLC.

[srainhoutx]

The fact that the "neutered" GFS is less effective in spotting cyclogenisis or that the Euro does not particularly well initialize them either is irrelevant to me. Of greater value might be those tools in determining near-mid term developmental & potential steering conditions.

The Euro has been clueless with this disturbance from the get go. THE NCEP Ensemble TC Genesis Probabilities were clearly 'sniffing' development as this wave exited Africa.

['CaneFreak]

Yep...it's there...weak but there. They just found some south winds.

But couldn't a new surface feature be forming there and the one they are checking out 120NM further west is in the process of dissipating?

I would they they would want to check that area out.

pressures are the lowest where they found the surface feature.

It's there

[NDG]

I think the recon is west of the possible LLC

[HURAKAN]

[SapphireSea]

It looks like a partial circulation is trying to form, but unless there is one to the SE, there doesn't appear - at this time - to be a closed LLC.

Looks pretty weak for now, but maybe more broad, so less removed from the MLC. If mild convection can persist into DMAX tonight, then this is most likely going to get going. IMO. I am not sold on the shear environment being conducive down the road, but that is wait and see still.

[Blown Away]

General idea of the areas in question??

[HURAKAN]

It looks like a wave ... if it was closed, then winds in the southern quadrant would be blowing from the west

[Dave]

000
URNT15 KNHC 281855
AF301 0104A DORIAN HDOB 18 20130728
184500 1930N 06209W 9769 00331 0145 +233 +221 182008 008 017 000 00
184530 1930N 06208W 9771 00330 0145 +235 +218 194008 008 017 000 00
184600 1930N 06206W 9772 00329 0145 +238 +213 205009 010 017 001 03
184630 1930N 06204W 9772 00330 0146 +235 +218 198009 010 018 000 03
184700 1930N 06202W 9770 00332 0146 +235 +220 207008 009 018 000 03
184730 1930N 06200W 9771 00332 0147 +238 +221 193008 008 018 000 00
184800 1930N 06158W 9770 00332 0147 +237 +223 188008 008 020 000 03
184830 1929N 06156W 9770 00333 0147 +237 +219 188008 009 020 001 03
184900 1929N 06154W 9772 00332 0147 +238 +217 184009 009 018 000 03
184930 1929N 06152W 9770 00333 0147 +235 +219 190009 009 018 000 03
185000 1929N 06150W 9774 00331 0147 +235 +222 190008 009 018 000 03
185030 1928N 06149W 9770 00332 0146 +233 +224 176005 007 /// /// 03
185100 1927N 06150W 9765 00336 0147 +234 +224 140005 005 017 001 03
185130 1926N 06152W 9770 00332 0147 +234 +224 139004 005 017 000 00
185200 1925N 06154W 9772 00330 0147 +235 +220 136004 004 018 000 03
185230 1925N 06156W 9770 00333 0147 +235 +218 118003 004 018 000 03
185300 1924N 06158W 9770 00333 0147 +235 +219 111003 003 018 000 03
185330 1923N 06159W 9772 00331 0147 +235 +218 113003 004 019 001 03
185400 1922N 06201W 9769 00334 0148 +235 +217 123002 003 017 001 00
185430 1922N 06203W 9772 00331 0147 +235 +220 160001 001 018 000 03
$$
;

[Blown Away]

552
WHXX01 KWBC 281853
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
1853 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 DORIAN (AL912013) 20130728 1800 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
130728 1800 130729 0600 130729 1800 130730 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 20.0N 62.5W 20.7N 65.7W 21.5N 68.8W 22.1N 71.8W
BAMD 20.0N 62.5W 21.0N 64.9W 21.9N 67.2W 22.7N 69.4W
BAMM 20.0N 62.5W 20.7N 65.3W 21.4N 67.9W 22.0N 70.3W
LBAR 20.0N 62.5W 21.1N 65.6W 22.1N 68.8W 23.1N 71.3W
SHIP 35KTS 40KTS 45KTS 49KTS
DSHP 35KTS 40KTS 45KTS 49KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
130730 1800 130731 1800 130801 1800 130802 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 22.7N 74.7W 23.5N 79.8W 24.8N 83.3W 26.1N 85.0W
BAMD 23.2N 71.4W 24.1N 75.4W 25.4N 78.9W 27.0N 81.4W
BAMM 22.4N 72.7W 23.2N 77.0W 24.7N 80.3W 26.7N 82.1W
LBAR 23.9N 74.0W 24.8N 78.4W 25.7N 81.4W 28.2N 82.6W
SHIP 53KTS 61KTS 71KTS 78KTS
DSHP 53KTS 61KTS 71KTS 48KTS

...INITIAL CONDITIONS...
LATCUR = 20.0N LONCUR = 62.5W DIRCUR = 285DEG SPDCUR = 22KT
LATM12 = 19.0N LONM12 = 57.6W DIRM12 = 283DEG SPDM12 = 21KT
LATM24 = 18.4N LONM24 = 53.6W
WNDCUR = 35KT RMAXWD = 80NM WNDM12 = 30KT
CENPRS = 1013MB OUTPRS = 1015MB OUTRAD = 100NM SDEPTH = S
RD34NE = 80NM RD34SE = 0NM RD34SW = 0NM RD34NW = 80NM

$$
NNNN

18z SHIP UPTO 90 MPH!!!

[cycloneye]

18z Best Track.

AL, 91, 2013072818, , BEST, 0, 200N, 625W, 35, 1013, WV

[Bad_Hurricane]

Interesting...

[Dave]

Few minutes old...

Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 28th day of the month at 18:55Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 301)
Storm Number: 04
Storm Name: Dorian (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 08

Mandatory Data...

Observation Time: Sunday, 18:53Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 19.4N 62.0W
Location: 274 miles (441 km) to the ENE (76°) from San Juan, Puerto Rico (USA).
Turbulence: None
Conditions Along Flight Route: In the clear
Pressure Altitude: 300 meters
Flight Level Wind: 5 knots (~ 5.8 mph) (Bearing was unavailable.)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: 21°C
Flight Level Dew Point: 20°C
Weather (within 30 nautical miles): Overcast / Undercast
Mean Sea Level Pressure (MSLP): 1015 mb (extrapolated)

Optional Data...

Estimated Surface Wind Direction: Bearing was unavailable.
Estimated Surface Wind Speed: 5 knots (~ 5.8 mph)

[chaser1]

If I were to guess, I would imagine we will continue to see sporadic convection throughout the afternoon, but more impressive bursting late this evening & into tomm. Based on the upper air charts, I would guess outflow to improve further tomm and expand. Assuming of course NHC's digestion of latter day model data (coupled by data from today's recon), would guess that the 5 p.m. TWO might bump chances of development to 50%-60% range.

[HURAKAN]