ATL: DORIAN - Post-Tropical - Discussion

[SFLcane]

Jeff masters...

Remains of Dorian growing more organized

The remains of Tropical Storm Dorian, located just north of Puerto Rico, are headed west to west-northwest at 15 - 20 mph. Satellite images show that ex-Dorian has a moderate area of heavy thunderstorms that have grown more organized this morning, with an intense clump of thunderstorms that have created a circular area of high cirrus clouds called a Central Dense Overcast (CDO) over the disturbance. There are no signs of a surface circulation on visible satellite images, but an AIr Force hurricane hunter aircraft is on call to investigate ex-Dorian Monday afternoon, if necessary. In their 8 am EDT Tropical Weather Outlook, NHC gave Dorian's remains a 40% chance of regenerating by Wednesday. I put these odds higher, at 50%. The primary impediment to development is the presence of an upper-level trough of low pressure to its west that ex-Dorian is running into. Strong upper-level southwesterly winds associated with this trough are creating a moderate 15 - 20 knots of wind shear and driving dry air into the west side of ex-Dorian. This shear is not expected to relent at all during the next few days. None of the reliable computer models for tropical cyclone genesis predict that ex-Dorian will regenerate, though the HWRF model, which is not reliable for predicting genesis, does show Dorian regenerating. Dorian's remains should continue moving west-northwest during the week, spreading over the Bahamas on Tuesday and Wednesday, and over Florida and Central Cuba on Thursday and Friday.

[cycloneye]

URNT15 KNHC 291638
AF301 0204A DORIAN HDOB 05 20130729
162930 1925N 06500W 9850 00290 0178 +247 +220 140012 012 /// /// 03
163000 1926N 06500W 9853 00286 0178 +249 +219 142012 012 /// /// 03
163030 1928N 06500W 9854 00285 0178 +249 +218 143012 012 /// /// 03
163100 1930N 06500W 9855 00286 0179 +246 +223 143011 012 /// /// 03
163130 1931N 06501W 9852 00287 0178 +247 +223 142010 010 /// /// 03
163200 1932N 06502W 9853 00286 0178 +249 +220 145010 010 /// /// 03
163230 1933N 06504W 9854 00286 0178 +248 +219 148009 010 /// /// 03
163300 1934N 06505W 9854 00286 0179 +245 +221 143008 009 /// /// 03
163330 1935N 06506W 9853 00287 0179 +245 +222 141008 008 /// /// 03
163400 1936N 06508W 9853 00287 0179 +245 +222 140007 008 /// /// 03
163430 1937N 06509W 9853 00287 0180 +245 +225 133006 007 /// /// 03
163500 1938N 06510W 9855 00286 0180 +245 +224 129006 006 015 000 03
163530 1939N 06512W 9852 00288 0180 +245 +223 122006 006 016 000 00
163600 1939N 06513W 9852 00288 0180 +245 +222 123007 007 016 001 00
163630 1940N 06515W 9854 00287 0180 +245 +220 119008 008 017 000 03
163700 1941N 06516W 9847 00293 0181 +239 +220 087008 011 016 001 03
163730 1942N 06518W 9864 00276 0181 +221 +219 030016 018 024 001 03
163800 1943N 06519W 9854 00287 0181 +224 +220 041012 016 025 000 00
163830 1943N 06521W 9854 00286 0182 +219 +217 050013 015 026 000 00
163900 1944N 06522W 9855 00285 0183 +220 +219 044013 014 024 000 03
$$

[cycloneye]

Who wants to continue the posting of the data? I have to go.

[NDG]

Doubt that the recon will find a closed circulation, yesterday it was better organized at the surface (IMO) and they couldn't close it.

[ScottNAtlanta]

I'm having a hard time buying into the "shear" argument



If you look at the outflow, in a sheared environment, you wouldn't really see it in multiple directions as per the graphic. I also think Hispaniola will put a stop to the dry air intrusion from the south. We will see if a new center is forming but this is the largest mass of convection I've seen with this thus far

[lester]

000
URNT15 KNHC 291648
AF301 0204A DORIAN HDOB 06 20130729
163930 1945N 06524W 9852 00287 0181 +223 //// 043013 016 023 000 05
164000 1946N 06525W 9854 00286 //// +222 //// 050013 014 023 000 05
164030 1947N 06526W 9857 00283 0180 +223 +220 046013 014 024 000 00
164100 1948N 06528W 9852 00287 0181 +224 +217 044015 016 025 000 03
164130 1949N 06529W 9851 00288 0179 +230 +216 052013 016 026 000 00
164200 1949N 06530W 9853 00284 0179 +230 +215 061015 018 026 000 00
164230 1950N 06532W 9855 00283 0179 +229 +209 056018 019 026 000 00
164300 1951N 06533W 9854 00282 0177 +235 +207 066017 018 027 001 00
164330 1952N 06535W 9852 00284 0177 +235 +208 071018 021 027 002 03
164400 1953N 06537W 9857 00281 0177 +238 +207 079016 018 029 000 03
164430 1953N 06538W 9857 00280 0176 +239 +207 094016 017 030 000 03
164500 1954N 06540W 9851 00283 0176 +238 +208 109015 017 028 003 03
164530 1955N 06541W 9854 00281 0175 +240 +206 109015 016 028 000 03
164600 1956N 06542W 9857 00279 0173 +241 +204 122016 017 /// /// 03
164630 1958N 06542W 9851 00282 0173 +238 +204 129018 018 024 000 03
164700 1958N 06542W 9851 00282 0173 +235 +205 128016 017 023 000 00
164730 2001N 06541W 9851 00283 0174 +234 +205 127019 020 026 000 00
164800 2002N 06541W 9852 00282 0173 +239 +201 130020 021 026 000 03
164830 2004N 06540W 9855 00278 0174 +241 +198 133022 022 026 000 00
164900 2005N 06540W 9853 00282 0173 +242 +196 133025 026 029 000 00
$$
;

[Blown Away]

Doubt that the recon will find a closed circulation, yesterday it was better organized at the surface (IMO) and they couldn't close it.

I agree, I'm interested to see if they focus on the SW corner of the convection @20.5N/67W or a little farther NE of that position??

[thundercam96]

Is anyone doing the recon obs/images for this storm on the recon thread?

[lester]

Is anyone doing the recon obs/images for this storm on the recon thread?

I'm doing the recon obs, I can't do images so if anyone would like to volunteer, that'd be fantastic!

[AtlanticWind]

http://www.ssd.noaa.gov/goes/east/watl/flash-rgb.html

There is a more definite spin to the cloud mass today , I have no idea if anything is at the surface yet though.

[wxman57]

I'm having a hard time buying into the "shear" argument

http://img600.imageshack.us/img600/3412/hvv7.jpg

If you look at the outflow, in a sheared environment, you wouldn't really see it in multiple directions as per the graphic. I also think Hispaniola will put a stop to the dry air intrusion from the south. We will see if a new center is forming but this is the largest mass of convection I've seen with this thus far

You're not looking at the big picture. Zoom out and look at a water vapor loop.

[Alyono]

I'm having a hard time buying into the "shear" argument

http://img600.imageshack.us/img600/3412/hvv7.jpg

If you look at the outflow, in a sheared environment, you wouldn't really see it in multiple directions as per the graphic. I also think Hispaniola will put a stop to the dry air intrusion from the south. We will see if a new center is forming but this is the largest mass of convection I've seen with this thus far

you would

notice NO outflow over the surface trough. pay little attention to the convection

[TropicalAnalystwx13]

I'm having a hard time buying into the "shear" argument

http://img600.imageshack.us/img600/3412/hvv7.jpg

If you look at the outflow, in a sheared environment, you wouldn't really see it in multiple directions as per the graphic. I also think Hispaniola will put a stop to the dry air intrusion from the south. We will see if a new center is forming but this is the largest mass of convection I've seen with this thus far

Agreed. The anticyclone looks to have become weak last night, but as it did yesterday, reformed in conjunction with the burst of storms associated with diurnal maximum. Outflow expanding in a clockwise fashion is not indicative of wind shear.

The upper-level wind map from UW-CIMSS says it's at least better established than earlier this morning. No where near as defined as yesterday though.

[otowntiger]

I'm having a hard time buying into the "shear" argument

http://img600.imageshack.us/img600/3412/hvv7.jpg

If you look at the outflow, in a sheared environment, you wouldn't really see it in multiple directions as per the graphic. I also think Hispaniola will put a stop to the dry air intrusion from the south. We will see if a new center is forming but this is the largest mass of convection I've seen with this thus far

From all accounts its not a wind shear 'argument', its pretty much wind shear fact.

[jhpigott]

notice NO outflow over the surface trough. pay little attention to the convection

When is this trough supposed to move out? Or is it forecasted to move out?

[Frank2]

The ULL to it's west is helping to ventilate it (sorry for the hotlink):

http://www.goes.noaa.gov/HURRLOOPS/huwvloop.html

Ugh - we'll see what happens...

[gatorcane]

The mid-level circulation (MLC) we see at 22N, 66W is quite vigorous but as has been mentioned, the actual low-level feature (LLC) is not there (fortunately). If it can somehow manage to form an LLC closer to this MLC feature, this certainly could get going but it still hasn't been able to do that and may never will.

[ScottNAtlanta]

I'm having a hard time buying into the "shear" argument

http://img600.imageshack.us/img600/3412/hvv7.jpg

If you look at the outflow, in a sheared environment, you wouldn't really see it in multiple directions as per the graphic. I also think Hispaniola will put a stop to the dry air intrusion from the south. We will see if a new center is forming but this is the largest mass of convection I've seen with this thus far

You're not looking at the big picture. Zoom out and look at a water vapor loop.

Unless its undercutting the outflow...I still must be missing something.
There is, however, still a lack of convergance

[lester]

000
URNT15 KNHC 291708
AF301 0204A DORIAN HDOB 08 20130729
165930 2028N 06539W 9854 00284 0181 +219 +207 128017 017 023 001 03
170000 2028N 06541W 9856 00283 0180 +217 +205 123016 016 024 000 00
170030 2027N 06542W 9850 00287 0179 +219 +200 123016 017 025 000 03
170100 2027N 06544W 9853 00284 0180 +216 +206 118017 017 026 000 03
170130 2027N 06546W 9853 00284 0180 +215 +211 113017 017 027 000 00
170200 2026N 06547W 9854 00282 0179 +217 +208 108019 019 028 000 03
170230 2026N 06549W 9853 00284 0180 +216 +210 109019 020 029 000 00
170300 2026N 06551W 9851 00285 0179 +217 +212 108019 020 029 000 03
170330 2025N 06553W 9854 00283 0179 +219 +212 104019 019 028 001 03
170400 2025N 06555W 9852 00284 0179 +218 +213 105020 021 028 001 00
170430 2025N 06556W 9854 00283 0178 +222 +207 106022 023 030 000 00
170500 2024N 06558W 9854 00283 0178 +221 +209 107023 024 030 000 03
170530 2024N 06600W 9854 00282 0178 +220 +213 104023 024 029 001 00
170600 2023N 06602W 9854 00281 0178 +220 +213 105022 023 030 000 00
170630 2023N 06603W 9851 00285 0178 +220 +217 105021 022 031 001 03
170700 2022N 06605W 9854 00282 0176 +224 +222 104021 023 027 000 05
170730 2022N 06607W 9854 00282 0177 +225 +223 108019 023 029 000 00
170800 2021N 06608W 9855 00280 0176 +227 +225 110019 020 027 001 01
170830 2020N 06610W 9852 00282 0175 +230 +224 115018 019 026 000 00
170900 2019N 06611W 9853 00281 0174 +230 +225 115017 018 025 000 00
$$
;

[Bocadude85]

12z GFS shows nothing but a tropical wave.