ATL: DORIAN - Post-Tropical - Discussion

[Aric Dunn]

Am I the only one having difficulties to obtain Recon data ? Nothing is displayed on Tropical Tidbits or Tropicalatlantic

thats because there is only a high altitude recon out there. no actual recon till the morning.

[Hammy]

Very very conservative...

SUMMARY OF 800 PM AST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...11.6N 54.8W
ABOUT 335 MI...540 KM ESE OF BARBADOS
ABOUT 445 MI...715 KM ESE OF ST. LUCIA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES

yeah that is pretty conservative considering all the satellite-derived estimates they went off of earlier all went up 10 plus kts.


side note.. the CDO is staying very symmetrical now. shear still dropping.

They don't usually raise it much on intermediates without undeniable evidence of rapid strengthening unless recon is out there.

[Chris_in_Tampa]

Am I the only one having difficulties to obtain Recon data ? Nothing is displayed on Tropical Tidbits or Tropicalatlantic

There is only a G-IV mission going around the storm. It is a high altitude mission and they are not taking wind measurements outside the aircraft like they have often done in the past. So in my recon system at Tropical Atlantic, the wind icons are a black dot to indicate missing winds. Dropsondes and the track of the HDOBs are still available though.

On Tropical Tidbits dropsondes are also available:
https://www.tropicaltidbits.com/recon/#NOAA90105ADORIAN

[AutoPenalti]

Very very conservative...

SUMMARY OF 800 PM AST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...11.6N 54.8W
ABOUT 335 MI...540 KM ESE OF BARBADOS
ABOUT 445 MI...715 KM ESE OF ST. LUCIA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES

I think they have it right. It’s a very small system with dramatic changes in the background. They are going to be conservative

[CrazyC83]

There may be a case for 50 kt, but that would be as high as I go without an ASCAT pass or Recon.

[Bostonriff]

This storm interests me for several reasons:

1) It did not appear to develop from a typical pre-peak sputtering easterly wave, but formed more or less in-place in the central tropical Atlantic in a "marble-rolling point" southwest of a SAL boundary. These "marbles" are fairly commonplace, but usually just squashed as shear, dry air, and poor upper support inhibit runaway convection. This year and this time, conditions were just right.

2) An utter lack of El Nino-type westerly shear from the eastern Pacific across northern South America of the sort that usually murders Carib-approaching systems dead in their tracks.

3) Instead, there's easterly to southeasterly shear at the mid-levels, i.e., in the direction of the motion of the storm. I've noted this occurrence in tandem with some powerful low-latitude storms in the past.

4) Marked reluctance by the TC to gain latitude.

5) It's just pokin' along at 12kt. (Too-fast movements are often an indication of overly brisk trade-winds undercutting and decoupling low-level circulation centers.)

6) Complete isolation of the TC from anything else nearby. There is no competing organized convection within a thousand miles in any direction. https://www.star.nesdis.noaa.gov/GOES/s ... &length=24

Summation: this is not a "usual" tropical cyclone. My hunch is that it's going to take a long track through the Caribbean south of Hispaniola, and whatever upper-low which had been recently forecast to develop in the northern Caribbean will, in upcoming model runs, be weaker and/or slide west ahead of the advancing tropical cyclone.

[CyclonicFury]

SAB up to T3.5

26/0000 UTC 11.5N 54.4W T3.5/3.5 DORIAN -- Atlantic

[Homie J]

SAB up to T3.5

26/0000 UTC 11.5N 54.4W T3.5/3.5 DORIAN -- Atlantic

Where did you find that at?

[Visioen]

Can't wait for recon tomorrow

[cycloneye]

SAB up to T3.5

26/0000 UTC 11.5N 54.4W T3.5/3.5 DORIAN -- Atlantic

Where did you find that at?

https://www.ssd.noaa.gov/PS/TROP/bulletins.html

[cycloneye]

TXNT28 KNES 260021
TCSNTL

A. 05L (DORIAN)

B. 26/0000Z

C. 11.5N

D. 54.4W

E. THREE/GOES-E

F. T3.5/3.5/D1.5/24HRS

G. IR/EIR/SWIR/WINDSAT

H. REMARKS...SYSTEM IS CHARACTERIZED BY A CENTRAL COLD COVER ATTM
BUT 7/10 BANDING WAS INFERRED IN A SSMIS PASS FROM 2219Z, WHICH WOULD
RESULT IN A DT OF 3.0. MET IS 3.0 BUT PT IS 3.5 BASED ON EYE-LIKE FEATURE
APPEARING IN THE 2146Z WINDSAT IMAGE. FT IS BASED ON PT BECAUSE BANDING
FEATURES COULD NOT BE DISCERNED IN THE CURRENT EIR IMAGERY.

I. ADDL POSITIONS

25/2146Z 11.5N 54.0W WINDSAT


...TURK

[Aric Dunn]

TXNT28 KNES 260021
TCSNTL

A. 05L (DORIAN)

B. 26/0000Z

C. 11.5N

D. 54.4W

E. THREE/GOES-E

F. T3.5/3.5/D1.5/24HRS

G. IR/EIR/SWIR/WINDSAT

H. REMARKS...SYSTEM IS CHARACTERIZED BY A CENTRAL COLD COVER ATTM
BUT 7/10 BANDING WAS INFERRED IN A SSMIS PASS FROM 2219Z, WHICH WOULD
RESULT IN A DT OF 3.0. MET IS 3.0 BUT PT IS 3.5 BASED ON EYE-LIKE FEATURE
APPEARING IN THE 2146Z WINDSAT IMAGE. FT IS BASED ON PT BECAUSE BANDING
FEATURES COULD NOT BE DISCERNED IN THE CURRENT EIR IMAGERY.

I. ADDL POSITIONS

25/2146Z 11.5N 54.0W WINDSAT


...TURK

well that would make it 65 to 70 mph.

[NDG]

Dropsondes confirm the very dry air all around Dorian, compared them to GFS's sounding forecasts and for the most part they match.

[Kazmit]

Can't wait for recon tomorrow

Hopefully it doesn't fall apart before then as many of these storms tend to.

[gatorcane]

Well 00Z model guidance is in and as expected the consensus has shifted to the right a bit now only clipping Hispaniola. The shift is due to the models taking into account a more organized Dorian from earlier runs today. Let’s hope Dorian finds some hostile conditions in the NE Caribbean or gets shredded by Hispaniola. I think if Dorian can make it into the Bahamas or north of Hispaniola with a good structure or as a cyclone, there could be favorable conditions for intensification down the road.

[CyclonicFury]

00z best track still 45 kt. Seems like NHC disregarded the SAB estimate.

[CrazyC83]

00z best track still 45 kt. Seems like NHC disregarded the SAB estimate.

Interesting, although I could see why. I'd probably have gone 50 kt, but still been lower than that estimate.

[HDGator]

00z best track still 45 kt. Seems like NHC disregarded the SAB estimate.

With both the GFS and ECMWF not giving much credence to strengthening in the near term, I guess that increased their inertia to change the current strength.
The G-IV dropsondes tonight appeared to confirm the dry air that Dorian will have to deal with over the next day.
I guess they chose to be conservative to see what happens overnight.

[Blown Away]

NHC at a fork, the TVCN Consensus is skimming the NE corner of Hispaniola missing the big mountains... Looking at the 00z intensity guidance, you can clearly see the models leveling off at TS/Cat 1 as Dorian passes by PR/Hispaniola compared to barely TD or open wave on earlier intensity runs... I bet the stay conservative at 11pm with Euro/GFS not being on board, but if the trend continues things might drastically change IMHO...

[Bostonriff]

The 12Z CMC runs it over Jamaica and western Cuba into the central Gulf: http://moe.met.fsu.edu/cgi-bin/cmctc2.c ... =Animation

(The Canadian model does not appear to have an 18Z run, or at least the moe.met.fsu.edu hosting page does not link one.)