Former TS Dorian

[Paul Robison]

From SWFMD.GOV:

South Florida Water Management District

Tropical Conditions Report

12:06PM Thursday, July 25, 2013 (eps)



Current Conditions:



LOCAL STORM/HURRICANE WATCHES/WARNINGS: None
Tropical Storm Force or Greater Winds Within 48 Hours: No



DISCUSSION:



At 5am, TROPICAL STORM DORIAN was located near 15.6N 34.5W, or about 700 miles west of the Cape Verde Islands, moving west-northwest near 17 mph with sustained winds up to 60 mph. Some strengthening is expected as Dorian heads generally westward along the southern edge of a high pressure ridge over the next few days. In the extended outlook, a weakness in the high pressure ridge located east of Florida would tend to draw the system more northward. If Dorian were to become a threat to the District, any potential impact of the system would be still about a week away.


BTW: Who was it that posted a forecast model image depicting a TS/hurricane hitting Houston coming from the Central Atlantic. Anybody think that could be Dorian?

[Belmer]

GFS models initialized as of 2am raise an eyebrow.
I read where this may not be an Ike storm as far as intensity goes, but the track ever so slightly looks familiar.
I know it's WAY to early to make a call on what this storm will do, but I know some of the meteorologist on air, like Travis Herzog, Tim Heller, Anthony Yanez basically said this would NOT be a Gulf storm, and were pretty adamant about it. While that still may be the case, I believe whenever you have a storm out in the Atlantic, anything is and can be possible and just like Ike did, it can give us surprise after surprise after surprise.
With that said.. Frank, Brooks and David Paul have done a good job on not hyping this storm, but constantly letting folks be aware of this storm and to monitor it.

Nonetheless, the models look interesting...

[srainhoutx]

Morning e-mail from Jeff:

Poorly organized tropical storm moving westward over the open Atlantic Ocean.

Discussion:
As suspected a couple of days ago Dorian has ran into somewhat unfavorable conditions with dry air and upper level wind shear taking a toll on the system. After a review of the first few visible images of the day, I am hard pressed to find a low level circulation, but for the sake of continuity assume there is likely a small circulation that remains under the current moderate bursts of convection. The overall cloud and convective pattern has greatly decline from yesterday, although Dorian has never had overly strong sustained convection. It is very possible that Dorian will not survive the next 48-72 hours dealing with dry air and upper level wind shear.

Track:
Dorian is moving generally W at near 20mph on the south side of a strong Atlantic high pressure ridge. The trade wind flow north of the system is clearly noted by the fast low cloud motions from ENE to WSW. The current ridge of high pressure helping to steer the system is forecasted to move generally westward in tandem with Dorian keeping the storm on a general westward track for the next 5 days. Model guidance is in good agreement with this westward track and this has been a southward adjustment over the past 24 hours. After 5 days what form Dorian is in begins to come into play as a trough of low pressure is expected to be in place along the mid-Atlantic coast into the NE US. Models have been generally backing down on the intensity and amplitude or depth of this trough and have been increasing more ridging over the SW Atlantic and FL north of Dorian. Many of the GFS ensembles which were showing a recurve of Dorian over the Bahamas are now more split between that pattern and some degree of entry into the Gulf of Mexico. For now expect to see Dorian in some form near eastern Cuba in about 5 days.

Intensity:
The bigger question marks comes on the intensity side of things. Dorian is struggling due to the dry air to its west and some upper level shear. As stated a few days ago, small systems such as Dorian tend to respond very rapidly to surrounding environmental changes and it is very easy to disrupt their small and fragile inner cores. It is likely that dry air has been getting entrained into the system which is keeping convection to a minimum. The recent increase in wind shear has resulted in the low level center becoming exposed on the western side of the thunderstorm activity at times and the system is not vertically aligned. The global forecast models have never been overly supportive of Dorian and it is very possible like with Chantal that Dorian degrades into an open wave at some point over the next few days. If Dorian does weaken more, it would be possible that it would be steered more westward and into some of the mountainous islands of the northern Caribbean Sea. The current NHC forecast is running on the higher side of the intensity guidance clustering especially in the 72-120 hour time period. Most of the models keep Dorian as a 50kt or weaker tropical storm and the ECMWF, GFS, and HWRF all show weakening to below a tropical storm…possibly an open wave.

[wxman57]

My vote is for dissipation within 12-24 hrs now. I think it's losing or has lost its LLC. Wave approaching the DR in 4-5 days. No redevelopment likely.

[srainhoutx]

My vote is for dissipation within 12-24 hrs now. I think it's losing or has lost its LLC. Wave approaching the DR in 4-5 days. No redevelopment likely.

I agree. August and September may be active enough...

TROPICAL STORM DORIAN DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042013
1100 AM AST FRI JUL 26 2013

VISIBLE SATELLITE IMAGES SHOW THAT THE CLOUD PATTERN OF DORIAN IS
RATHER DISORGANIZED...WITH LITTLE OR NO EVIDENCE OF BANDING
FEATURES. THE CURRENT INTENSITY ESTIMATE IS HELD AT 45 KT IN
AGREEMENT WITH A DVORAK ESTIMATE FROM TAFB AND A RECENT ASCAT
OVERPASS. WATER VAPOR IMAGERY AND TOTAL PRECIPITABLE WATER DATA
INDICATE THAT DORIAN WILL BE ENCOUNTERING DRY AIR OVER THE NEXT DAY
OR SO AND THIS...ALONG WITH MODERATE WEST-SOUTHWESTERLY
SHEAR...SHOULD CAUSE SOME WEAKENING OF THE TROPICAL CYCLONE. LATER
IN THE FORECAST PERIOD...THE DYNAMICAL GUIDANCE SHOW ONLY A SLIGHT
DECREASE IN SHEAR. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO
THE PREVIOUS ONE AND IS ONLY A LITTLE BELOW THE STATISTICAL-
DYNAMICAL GUIDANCE. AN ALTERNATIVE SCENARIO...WHICH IS CERTAINLY
POSSIBLE...IS THAT DORIAN COULD DEGENERATE INTO A TROPICAL WAVE
WITHIN THE NEXT COUPLE OF DAYS.

THE STORM CONTINUES TO MOVE RAPIDLY WEST-NORTHWESTWARD IN THE FLOW
SOUTH OF A STRONG MID- TO LOW-LEVEL HIGH PRESSURE AREA. THE GLOBAL
MODELS CONTINUE TO FORECAST THE RIDGE TO BUILD WESTWARD TO THE
NORTH OF DORIAN...WHICH SHOULD CAUSE THE TROPICAL CYCLONE TO MOVE
GENERALLY TOWARD THE WEST OR SLIGHTLY NORTH OF WEST THROUGH THE
FORECAST PERIOD. THE OFFICIAL TRACK FORECAST IS SIMILAR TO THE
PREVIOUS NHC TRACK AND LEANS TOWARD THE GFS AND HWRF SOLUTIONS.
THIS IS ALSO CLOSE TO...BUT A LITTLE SLOWER THAN...THE FLORIDA
STATE UNIVERSITY SUPERENSEMBLE.

FORECAST POSITIONS AND MAX WINDS

INIT 26/1500Z 17.7N 43.4W 45 KT 50 MPH
12H 27/0000Z 18.1N 46.4W 40 KT 45 MPH
24H 27/1200Z 18.7N 50.3W 40 KT 45 MPH
36H 28/0000Z 19.2N 54.2W 40 KT 45 MPH
48H 28/1200Z 19.7N 58.2W 40 KT 45 MPH
72H 29/1200Z 20.2N 64.4W 40 KT 45 MPH
96H 30/1200Z 20.5N 70.0W 45 KT 50 MPH
120H 31/1200Z 21.5N 75.0W 45 KT 50 MPH

$$
FORECASTER PASCH

[srainhoutx]

TS Dorian's center is completely exposed at this time and unless storms begin to fire again this evening, its life may be near the end. That said the latest track as switched to W from WNW and the 12Z GFS Ensembles are agreement that a more Westerly motion will remain in the days ahead if it is still an identifiable disturbance.

[tireman4]

Do we call Bones yet?

[srainhoutx]

TROPICAL STORM DORIAN DISCUSSION NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042013
500 PM AST FRI JUL 26 2013

UNDER THE INFLUENCE OF WESTERLY SHEAR AND DRIER AIR...DORIAN HAS
BECOME EVEN LESS ORGANIZED THAN IT WAS EARLIER TODAY. VISIBLE
SATELLITE IMAGES INDICATE THAT THE LOW-LEVEL CENTER HAS BECOME
DISPLACED TO THE WEST OF AN AREA OF WEAKENING DEEP CONVECTION.
ALSO...ANIMATION OF THE IMAGERY SHOWS THAT CIRCULATION IS BARELY
CLOSED AT THIS TIME. USING A BLEND OF DVORAK ESTIMATES FROM SAB
AND TAFB...THE ADVISORY INTENSITY IS REDUCED TO 40 KT. THE
OFFICIAL WIND SPEED FORECAST NOW SHOWS GRADUAL WEAKENING WITH
DISSIPATION BY DAY 5...IN GENERAL AGREEMENT WITH THE GFDL AND HWRF
GUIDANCE. GIVEN THE CURRENT TRENDS...HOWEVER...THE SYSTEM COULD
DEGENERATE INTO AN OPEN WAVE MUCH SOONER THAN THAT.

THE LATEST CENTER FIXES INDICATE THAT DORIAN IS MOVING RAPIDLY
WESTWARD...SLIGHTLY TO THE SOUTH OF THE PREVIOUS TRACK. A STRONG
LOW- TO MID-LEVEL HIGH PRESSURE SYSTEM TO THE NORTH OF DORIAN IS
FORECAST TO BUILD WESTWARD WITH TIME BY THE GLOBAL MODELS. THIS
SHOULD MAINTAIN A GENERALLY WESTWARD MOTION FOR THE NEXT SEVERAL
DAYS. THE OFFICIAL TRACK FORECAST IS SHIFTED A BIT TO THE SOUTH OF
THE PREVIOUS ONE AND IS ABOUT IN THE MIDDLE OF THE GUIDANCE
ENVELOPE. THE LATEST ECMWF MODEL TRACK IS A LITTLE FARTHER NORTH
BUT THAT MODEL DOES NOT INITIALIZE NOR FORECAST A CLOSED SURFACE
CIRCULATION.



FORECAST POSITIONS AND MAX WINDS

INIT 26/2100Z 17.8N 45.8W 40 KT 45 MPH
12H 27/0600Z 18.2N 48.8W 40 KT 45 MPH
24H 27/1800Z 18.6N 52.8W 35 KT 40 MPH
36H 28/0600Z 19.0N 56.7W 35 KT 40 MPH
48H 28/1800Z 19.5N 60.5W 30 KT 35 MPH
72H 29/1800Z 20.0N 67.0W 30 KT 35 MPH
96H 30/1800Z 20.5N 74.0W 25 KT 30 MPH
120H 31/1800Z...DISSIPATED

$$
FORECASTER PASCH

[TexasBreeze]

TS Flossie in the East/Central Pac could become more interesting than Dorian in seeing if it strikes Hawaii as a classified ts or td. NHC says it will be close.

[srainhoutx]

It appears that Dorian was able to slip underneath a weak anti cyclonic upper ridge and maintained its self over night. The track guidance suggest westward bound for the duration and the statistical SHIP intensity guidance strengthens Dorian as it passes N of Puerto Rico and Hispaniola.

[srainhoutx]

RECON has been tasked for tomorrow if need be.

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1200 PM EDT SAT 27 JULY 2013
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 28/1100Z TO 29/1100Z JULY 2013
TCPOD NUMBER.....13-057

I. ATLANTIC REQUIREMENTS
1. TROPICAL STORM DORIAN
FLIGHT ONE -- TEAL 71
A. 28/1730Z
B. AFXXX 0104A DORIAN
C. 28/1600Z
D. 19.9N 61.4W
E. 28/1630Z TO 28/2030Z
F. SFC TO 10,000 FT

FLIGHT TWO -- TEAL 72
A. 29/0530Z
B. AFXXX 0204A DORIAN
C. 29/0230Z
D. 20.4N 65.0W
E. 29/0300Z TO 29/0700Z
F. SFC TO 10,000 FT

2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 12-HRLY FIXES
WHILE SYSTEM MAINTAINS ITS INTEGRITY.

[srainhoutx]

Do we call Bones yet?

Stick a fork in it. It's done....

[Belmer]

I agree. Looks like the NHC will pull the plug at 5pm and downgrade it to a remnant low or wave.
It is July afterall, don't see storms like these survive too often. Things will get going in August.. which is just a few days away.

[srainhoutx]

It appears the remnants of Dorian made a bit of a come back overnight and is now designated 91L. RECON is scheduled to investigate from St Croix later today as well.

[tireman4]

Yep Srain, 2 pm I think. Humm, I just wonder what they will find. Will Dr. McCoy have to reevaluate? That and much more later today.

[rnmm]

The plane has already taken off, should have more info on ex-Dorian real soon

[srainhoutx]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT SUN JUL 28 2013

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

A TROUGH OF LOW PRESSURE...ASSOCIATED WITH THE REMNANTS OF DORIAN...
IS PRODUCING AN AREA OF SHOWERS AND THUNDERSTORMS...AS WELL AS
WINDS TO GALE FORCE...A FEW HUNDRED MILES NORTH AND NORTHEAST OF
THE LEEWARD ISLANDS. AN AIR FORCE RECONNAISSANCE AIRCRAFT IS
CURRENTLY INVESTIGATING THE SYSTEM TO DETERMINE IF A CLOSED
LOW-LEVEL CIRCULATION AND A WELL-DEFINED CENTER HAVE REDEVELOPED.
ENVIRONMENTAL CONDITIONS ARE MARGINALLY CONDUCIVE FOR
REGENERATION...BUT ONLY A SMALL INCREASE IN ORGANIZATION COULD LEAD
TO THE REFORMATION OF A TROPICAL CYCLONE. THIS SYSTEM HAS A MEDIUM
CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS AS IT MOVES WESTWARD TO WEST-NORTHWESTWARD AT 15 TO
20 MPH...PASSING NORTH OF THE LEEWARD ISLANDS AND PUERTO RICO TODAY
AND MONDAY...AND MOVING OVER THE TURKS AND CAICOS ISLANDS AND
SOUTHERN BAHAMAS ON TUESDAY.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BERG

[srainhoutx]

Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 28th day of the month at 18:18Z
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: 06

Mandatory Data...

Observation Time: Sunday, 18:15Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 20.4N 62.2W
Location: 287 miles (462 km) to the ENE (61°) from San Juan, Puerto Rico (USA).
Turbulence: None
Conditions Along Flight Route: In the clear
Pressure Altitude: 310 meters
Flight Level Wind: From 100° at 30 knots (From the E at ~ 34.5 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: 24°C
Flight Level Dew Point: 24°C
Weather (within 30 nautical miles): Shower(s) (continuous or intermittent precipitation - from cumuliform clouds)
Mean Sea Level Pressure (MSLP): 1014 mb (extrapolated)

Optional Data...

Estimated Surface Wind: From 110° at 35 knots (From the ESE at ~ 40.2 mph)

[srainhoutx]

SPECIAL TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
350 PM EDT SUN JUL 28 2013

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

DATA FROM AN AIR FORCE RECONNAISSANCE MISSION IN THE REMNANTS OF
DORIAN...LOCATED A COUPLE HUNDRED MILES NORTH OF THE LEEWARD
ISLANDS...INDICATE THAT THE DISTURBANCE DOES NOT HAVE A WELL-
DEFINED CENTER OF CIRCULATION AND CONSISTS OF A SHARP SURFACE
TROUGH. THE SYSTEM IS PRODUCING WINDS TO GALE FORCE WELL NORTH OF
THE LEEWARD ISLANDS...HOWEVER THE ASSOCIATED SHOWER AND
THUNDERSTORM ACTIVITY HAS WEAKENED DURING THE PAST FEW HOURS.

ENVIRONMENTAL WINDS ARE EXPECTED TO BE ONLY MARGINALLY CONDUCIVE FOR
REGENERATION DURING THE NEXT COUPLE OF DAYS. THIS SYSTEM HAS A
MEDIUM CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES WESTWARD TO WEST-NORTHWESTWARD AT
AROUND 20 MPH...PASSING NORTH OF THE LEEWARD ISLANDS AND PUERTO
RICO THROUGH MONDAY...AND MOVING OVER THE TURKS AND CAICOS ISLANDS
AND SOUTHERN BAHAMAS ON TUESDAY.

ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE FOUND IN HIGH SEAS
FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPS
HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BERG

[srainhoutx]

The 12Z HWRF suggest the remnants of Dorian may slowly strengthen as it nears Andros Island and pass through the Florida Straights just N of Cuba. The 12Z GFS Ensemble tracks suggest a somewhat similar solution that may bring a weak TD or TS Dorian into the SE Gulf of Mexico.