ATL: Ex-Tropical Storm GASTON - Discussion

[fci]

NHC pretty smart in not issuing advisories over the past 24 hours as members on this board clamored for them and insisted that Gaston had risen from the dead.
Looks pretty pathetic now.
No way is this more than 60% at 2 AM and that high only because it would be bizarre to go from 80% to 40% in 6 hours.
Just my opinion.
Let's see......

Hmmm, guess that years of formal education and experience in understanding and forecasting tropical cyclones is actually worth something

I personally think that ex-Gaston does have a decent chance, but it might take a while for it to get its act back together.

That's why the NHC and Pros like you are paid for your knowledge and understanding and amateurs like me should just lurk and keep quiet (even at like 2 AM)!!!!

[supercane]

06Z best track update from ATCF:
AL, 09, 2010090506, , BEST, 0, 167N, 492W, 25, 1009, LO, 34, NEQ, 0, 0, 0, 0, 1012, 200, 60, 0, 0, L, 0, , 0, 0, GASTON, S,
AL, 09, 2010090500, , BEST, 0, 167N, 477W, 25, 1008, LO, 0, , 0, 0, 0, 0, 1011, 180, 45, 35, 0, L, 0, , 0, 0, GASTON, S,



SAB Dvoraks:
DATE/TIME LAT LON CLASSIFICATION STORM
05/0615 UTC 16.8N 49.2W T1.0/1.5 GASTON
04/2345 UTC 16.8N 47.6W T1.0/2.0 GASTON
04/1745 UTC 16.5N 46.6W T1.5/2.0 GASTON

[ColinDelia]

So only gained .1 of latitude in 12 hours.

[bob rulz]

So only gained .1 of latitude in 12 hours.

.3 actually.

[ColinDelia]

6z SHIPS has 13-15 knots of easterly shear for the first 18 hours dropping to 10 knots for the next 12 hours and then dropping even further after that. Apparently the upper level easterlies have been driving dry air into gaston's core.

200 mb streamlines

[ColinDelia]

So only gained .1 of latitude in 12 hours.

.3 actually.

I used ATCF "best track"

18z. 16.6 N 46.6W
6z 16.7N 49.2W (12 hours later)

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 010.invest

[abajan]

Another thing too is that WXMAN stated tonight that this keeps gaining latitude. Yet, the TWO's keep mentioning that it's moving "westard".... Any thoughts on this?

According to this chart, anything between 258.75° and 281.25° is considered west.

[Nimbus]

Ex Gaston didn't get any convective bursts overnight that could be all for a while. Sometimes these areas just don't develop, if the ULL over PR doesn't fan up some convection Gaston is done.

[Blown Away]

TAFB showing ex-Gaston as "Possible Cyclone" SE or PR in 72 hours. IMO, Gaston is working hard to maintain convection and I think we will see improvement today. I'm ready to see the visible this morning, I'm thinking we will still see a vigorous LLC.

[fasterdisaster]

The LLC remains intact but convection is still zilch.

http://www.ssd.noaa.gov/goes/east/catl/flash-vis.html
http://www.ssd.noaa.gov/goes/east/catl/flash-wv.html

Still not dead yet

[Gustywind]

[cycloneye]

I posted this mornings San Juan discussion at the Caribbean thread, but I am reposting it here because is a complete piece of information about what is going on and what may occur in the next few days. Is a long one.

http://forecast.weather.gov/product.php ... glossary=1


AREA FORECAST DISCUSSION...DELAYED
NATIONAL WEATHER SERVICE SAN JUAN PR
623 AM AST SUN SEP 5 2010

.SYNOPSIS...TUTT LOW WILL CONTINUE MOVING WEST NORTHWEST ACROSS
THE LOCAL AREA TODAY AND THEN AWAY FROM THE REGION TONIGHT
THROUGH MONDAY. UPPER LEVEL HIGH PRESSURE WILL EXTEND INTO THE
LOCAL AREA MONDAY NIGHT AND TUESDAY. THE REMNANTS OF TROPICAL
STORM GASTON ARE EXPECTED TO APPROACH THE LOCAL AREA TUESDAY AND
THEN MOVE NEAR OR ACROSS THE LOCAL ISLANDS TUESDAY NIGHT THROUGH
WEDNESDAY OR THURSDAY...POSSIBLY AS A TROPICAL CYCLONE.

&&

.DISCUSSION...AS NOTED ABOVE...TUTT LOW OVER THE FA AT THIS TIME
AND WILL CONTINUE MOVING STEADILY WEST NORTHWEST THROUGH MONDAY.
ASSOCIATED LOW TO MID LEVEL REFLECTIONS APPEAR TO BE LOCATED JUST
WEST OF THE LEEWARD ISLANDS...AND WILL MOVE ACROSS THE U.S.
VIRGIN ISLANDS AND PUERTO RICO TODAY THROUGH EARLY TONIGHT. THESE
FEATURES WILL COMBINE WITH AVAILABLE MOISTURE...LOCAL EFFECTS AND
UPPER DIVERGENCE FROM THE TUTT...TO CONTINUE TO PRODUCE SOME
CLOUDINESS...SHOWERS AND A FEW THUNDERSTORMS ACROSS THE LOCAL
ISLANDS TODAY...BUT WITH THE FOCUS BEING OVER THE CENTRAL AND
WESTERN INTERIOR...WEST AND SOUTHWEST SECTIONS OF PUERTO RICO
THIS AFTERNOON. A COUPLE OF THUNDERSTORMS COULD BECOME STRONG TO
SEVERE...WITH STRONG AND GUSTY WINDS...HAIL AND FREQUENT CLOUD TO
GROUND LIGHTNING...AS WELL AS PERIODS OF HEAVY RAINFALL. FOR
MONDAY...EXPECT SIMILAR CONDITIONS TO TODAY WITH SOME
CLOUDINESS...SHOWERS AND A COUPLE OF THUNDERSTORMS AGAIN...BUT
THIS TIME FOCUSED OVER THE CENTRAL AND WESTERN INTERIOR...WEST
AND NORTHWEST SECTIONS OF PUERTO RICO. FOR MONDAY NIGHT...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED.

THAT WAS THE EASY PART OF THE FORECAST. FOR TUESDAY THROUGH
WEDNESDAY AND PROBABLY THURSDAY...THE LOCAL WEATHER WILL BE
DETERMINED BY THE REMNANTS OF TROPICAL STORM GASTON...AND EXACTLY
WHAT THIS SYSTEM DOES. THIS REMNANT LOW OF GASTON WAS LOCATED NEAR
LATITUDE 16.5 NORTH AND LONGITUDE 49.5 WEST EARLY THIS MORNING AND
WAS MOVING WEST AT NEAR 12 KNOTS. THERE REMAINS AN ABOVE NORMAL
AMOUNT OF UNCERTAINTY WITH THE LOCAL FORECAST FOR MIDWEEK. TPC/NHC
CONTINUES TO GIVE THIS SYSTEM A HIGH CHANCE OF RE-DEVELOPMENT TO A
TROPICAL CYCLONE AND INDICATE THAT IT COULD BECOME A TROPICAL
DEPRESSION LATER TODAY OR MONDAY. SATELLITE DATA INDICATE THAT THE
LOW LEVEL CIRCULATION REMAINS PRETTY WELL DEFINED BUT SHOWERS AND
THUNDERSTORMS HAVE BEEN AND REMAIN LIMITED...ESPECIALLY ON THE
EAST SIDE OF THE CIRCULATION...PROBABLY DUE TO THE ENTRAINMENT OF
DRY AIR (SAL). ASSUMING THE TUTT LOW CONTINUES MOVING AWAY AS
EXPECTED...THE SHEAR AHEAD OF THE SYSTEM SHOULD REMAIN FAIRLY LOW
(12 OR 13 KNOTS OR LESS) FOR THE NEXT FEW DAYS...AND IT IS NOW
MOVING OVER WARMER OCEAN WATER AND TOWARD AN AREA OF INCREASING
UPPER OCEAN HEAT CONTENT...PARTICULARLY FROM 57 OR 58 DEGREES WEST
AND WESTWARD THROUGH THE EASTERN CARIBBEAN.

TO COMPLICATE MATTERS...GLOBAL MODELS HAVE GENERALLY BEEN ALL
OVER THE PLACE WITH THIS SYSTEM...WITH THE GFS GOING FROM A
HURRICANE FORECAST 36 TO 48 HOURS AGO TO BASICALLY A WEAK LOW
ALONG A REMNANT TROPICAL WAVE AXIS WITH THE 05/00Z RUN.
INTERESTINGLY...MUCH OF THE NHC HURRICANE MODEL GUIDANCE CONTINUES
TO INDICATE A TRACK VERY NEAR OR ACROSS THE FA...WITH INTENSITY
GUIDANCE RANGING FROM A TROPICAL DEPRESSION OR LOW END TROPICAL
STORM (GFDL) TO A STRONG TROPICAL STORM TO EVEN A HURRICANE (SHIPS
AND LGEM). SO...AS MENTIONED THE UNCERTAINTY IS VERY HIGH AND WITH
THE TIMING APPARENTLY A BIT QUICKER THAN WHAT IT SEEMED A COUPLE
OF DAYS AGO...CUTTING DOWN ON POTENTIAL PREPAREDNESS TIME.

IRRESPECTIVE OF RE-DEVELOPMENT INTO A TROPICAL CYCLONE...WE
EXPECT SIGNIFICANT IMPACTS LOCALLY ANYWAY...WITH AN EXTENDED
PERIOD OF ACTIVE WEATHER...WITH FRESH TO STRONG WINDS...SHOWERS
AND THUNDERSTORMS WITH PERIODS OF HEAVY RAINFALL AND THE POTENTIAL
FOR SOME FLOODING...AND DETERIORATING MARINE CONDITIONS.

GIVEN THE LONG HOLIDAY WEEKEND AND THE UNCERTAINTIES WITH THIS
APPROACHING REMNANT LOW OF GASTON...ALL LOCAL EMERGENCY
MANAGERS...GOVERNMENT OFFICIALS...RESIDENTS AND VISITORS SHOULD
CONTINUE TO CLOSELY MONITOR THIS SYSTEM...STAY ABREAST OF THE
LATEST FORECASTS...AND BE READY TO TAKE QUICK ACTION...SHOULD IT
BECOME NECESSARY.

&&

.AVIATION...A VCSH OR -SHRA WILL BE POSSIBLE ACROSS THE VI...TJSJ
AND TJBQ THROUGH 05/14...WITH PREVAILING VFR CONDITIONS ALL SITES.
AFT 05/16Z...EXPECT SHRA AND TSRA DEVELOPMENT TO RESULT IN
LOCALIZED MOUNTAIN OBSCURATIONS ACROSS THE CORDILLERA CENTRAL AS
WELL AS BRING BRIEF MVFR CIGS AND VSBYS TO TJPS AND TJMZ FROM
05/17Z-05/22Z. PREVAILING LLVL NE WINDS OF 10-15 KTS ARE EXPECTED
TODAY.

&&

.MARINE...GENERALLY EXPECT WINDS OF 18 KNOTS OR LESS AND SEAS OF 5
FEET OR LESS ACROSS THE REGIONAL WATERS THROUGH MONDAY NIGHT.
WINDS AND SEAS WILL INCREASE SIGNIFICANTLY TUESDAY THROUGH
WEDNESDAY...AS THE REMNANTS OF GASTON APPROACH AND THEN MOVE
ACROSS THE LOCAL AREA. SHOULD GASTON RE-DEVELOP INTO A TROPICAL
CYCLONE...SIGNIFICANT CHANGES TO THE ONGOING LOCAL MARINE
FORECAST WOULD BE NECESSARY...PROBABLY WITH A VERY SHORT NOTICE.
THEREFORE...ALL LOCAL MARINE INTERESTS SHOULD CONTINUE TO CLOSELY
MONITOR LATER FORECASTS FOR UPDATES.

[cycloneye]

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SUN SEP 5 2010

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

SHOWER AND THUNDERSTORM ACTIVITY REMAINS DISORGANIZED IN ASSOCIATION
WITH THE REMNANT LOW OF GASTON LOCATED ABOUT 750 MILES EAST OF THE
LEEWARD ISLANDS. HOWEVER...ENVIRONMENTAL CONDITIONS APPEAR
CONDUCIVE FOR DEVELOPMENT OF THIS SYSTEM AND A TROPICAL DEPRESSION
COULD RE-FORM IN THIS AREA DURING THE NEXT DAY OR TWO. THERE IS A
HIGH CHANCE...70 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE AGAIN DURING THE NEXT 48 HOURS.

RADAR IMAGERY FROM MEXICO INDICATES THAT A BROAD AREA OF LOW
PRESSURE LOCATED OVER THE EXTREME SOUTHWESTERN GULF OF MEXICO HAS
CHANGED LITTLE IN ORGANIZATION DURING THE LAST SEVERAL HOURS.
ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR ADDITIONAL
DEVELOPMENT AND A TROPICAL DEPRESSION COULD FORM DURING THE NEXT
DAY OR SO BEFORE THE SYSTEM MOVES INLAND. THERE IS A HIGH
CHANCE...60 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS AS IT MOVES NORTHWESTWARD AT 5 TO 10 MPH.

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

$$
FORECASTER CANGIALOSI/PASCH

[cpdaman]

i don' think i've ever seen something so paltry have a 70% ....attatched to it.

[Gustywind]

Convection is refiring slightly since the last hour... near the presume low center and south of the 16N.

[CourierPR]

Last night NWS San Juan said that the system was cut off from moisture in the ITCZ to its south. With convection developing on its south side, perhaps that is changing this morning.

[cycloneye]

SAB Dvorak=05/1145 UTC 16.9N 50.0W T1.5/1.5 GASTON -- Atlantic

[WeatherGuesser]

.....

Wrong thread.

[Gustywind]

Let's wait for the Best Track right now.

[Gustywind]