ATL: Ex-Tropical Storm GASTON - Discussion

[jinftl]

At least in the next 48 hours...what happens after that?

The NHC seems a little less confident of this making the cut...

[Florida1118]

At least in the next 48 hours...what happens after that?

The NHC seems a little less confident of this making the cut...

Yes but they keep toying with "at anytime" and "Some development is possible"

[jinftl]

Dr. Jeff Masters discussion earlier today on this system:

Even if Gaston does manage to become a tropical depression today, development will be slow over the next few days, due to the dry air. When Gaston passes over or just to the northeast of the Lesser Antilles Islands early Tuesday morning, the storm is unlikely to have more than 50 mph winds. More significant development is possible later in the week, as the atmosphere should be moister for Gaston. Gaston may threaten Puerto Rico on Wednesday, the Dominican Republic on Thursday, and Haiti, Jamaica, and/or the Turks and Caicos Islands by Friday, depending upon the storm's interaction with a trough of low pressure expected to move off the U.S. East Coast later this week.

The earlier Gaston develops into a tropical storm, the more likely it is to "feel" the upper-level winds of the approaching trough, and curve more to the northwest. The HWRF model predicts Gaston will develop by Monday, and pass just northeast of the Lesser Antilles Islands Tuesday morning. The GFDL model, on the other hand, delays development until Wednesday, keeping Gaston in the Caribbean. The GFDL has Gaston hitting Jamaica as a strong tropical storm on Friday morning. However, the GFDL forecast is dubious, because on Wednesday and Thursday, Gaston may have an encounter with the high mountains of the island shared by the Dominican Republic and Haiti, Hispaniola, which could easily destroy a system as fragile as Gaston.
http://www.wunderground.com/blog/JeffMa ... rynum=1608

[bvigal]

Poor Gaston almost completely cut off from moisture inflow from ITCZ, which, by the way, looks awfully dry, too.


(What's up with imageshack tonight? s l o w !)

[HurricaneMaster_PR]

05/2345 UTC 17.1N 52.2W T2.0/2.0 GASTON -- Atlantic

[fasterdisaster]

05/2345 UTC 17.1N 52.2W T2.0/2.0 GASTON -- Atlantic

Dvorak numbers and satellite presentation are slowly improving.

[Bailey1777]

you guys trying to kill off poor gaston, he will make all this dying talk look silly by this time tomorrow IMO. his ciculation is alive and well, just wait and see

[hurricaneCW]

you guys trying to kill off poor gaston, he will make all this dying talk look silly by this time tomorrow IMO. his ciculation is alive and well, just wait and see

For a system that's going into the Caribbean where the highest heat content lies is not something I want to see. I hope poor Gaston remains poor and fades away because those Caribbean systems can rapidly turn things up Wilma style.

[Steve H.]

Convection waning again......I just don't know what to make of this...... a lot of dry air though.

[Dean4Storms]

you guys trying to kill off poor gaston, he will make all this dying talk look silly by this time tomorrow IMO. his ciculation is alive and well, just wait and see

There's much against it, very little global model support, dry air and an ULL that Gaston is gaining on.

[cycloneye]

Here is tonights updated discussion by the San Juan NWS.

Blown Away, I know you like these long discussions from San Juan.

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
947 PM AST SUN SEP 5 2010

.UPDATE...WINDS HAVE SHIFTED MORE EAST SOUTHEAST FROM THE 12Z
SOUNDING AND PRECIPITABLE WATER HAS INCREASED FROM 24 HOURS AGO
BUT INCREASED FROM 12 HOURS AGO. SHOWERS AND THUNDERSTORMS
CONTINUE IN THE ATLANTIC AND CARIBBEAN WATERS WITH A FEW SHOWER
INCURSIONS OVER CABO ROJO AND NORTHEAST PUERTO RICO. OTHERWISE ALL
SHOWERS OVER LAND HAVE DISSIPATED. ONE SHOWER WAS NOTED OVER THE
BEACHES IN SOUTHERN SAINT CROIX AND OVER THE WATERS THERE.


&&

.DISCUSSION...THE 05/18Z MODEL RUNS CONTINUE BRINGING THE REMNANT LOW
OF GASTON ACROSS THE CARIBBEAN WATERS SOUTH OF PUERTO RICO
TUESDAY NIGHT AND WEDNESDAY MORNING. ALTHOUGH DIFFICULT TO
TRACK...THIS LOW APPEARS TO BE MOVING AT ABOUT 9 TO 12 KNOTS DUE
WEST AND WOULD PASS SOUTH OF PUERTO RICO IN ABOUT THE SAME TIME
FRAME IF IT WERE TO CONTINUE UNCHANGED. THE NAM CARRIES THE LOW
JUST SOUTH OF PUERTO RICO IN A SOMEWHAT SPLINTERED FORM. THE GFS
CARRIES THE LOW ACROSS AS AN OPEN WAVE ABOUT 180 MILES SOUTH OF
SAN JUAN AT 08/06Z. THE ECMWF 12Z RUN LOSES THE LOW BUT SHOWS A
WEAK TURNING IN AN OPEN WAVE AT ABOUT 240 MILES SOUTH OF SAN JUAN
ALSO AROUND 08/06Z. THE UKMET 12Z RUN BRINGS THE LOW ACROSS
VIRTUALLY UNCHANGED...OR SLIGHTLY STRONGER...ABOUT 225 MILES SOUTH
OF SAN JUAN AT 08/02Z. THE FORMER MODELS HAVE WINDS AT 850 MB
WHICH RANGE FROM 10 TO 25 KNOTS...WHILE THE UKMET SHOWS WINDS UP
TO 35 KNOTS ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS ALSO AT
850 MB.

THE REMNANT LOW...CURRENTLY LOCATED ABOUT 860 MILES EAST
SOUTHEAST OF SAN JUAN...HAS BEEN STRUGGLING AGAINST A NUMBER OF
FACTORS WHICH MAY ULTIMATELY PROVE TO BE OVERWHELMING. GASTON HAS
BEEN NEARLY CUT OFF FROM ITS MOISTURE STREAM IN THE ITCZ AND IS
NEARLY ENCLOSED BY DRIER AIR AS EVIDENCED BY SHARPLY DEFINED
OUTFLOW BOUNDARIES MOVING EAST OUT OF THE MAIN CONVECTION. THE
AIR TO OUR EAST AHEAD OF THE LOW IS ALSO A LITTLE DRIER. WINDS AT
250 MB CONTINUE TO BE FAIRLY STRONG...VARYING FROM 25 TO 40
KNOTS. THIS SHEAR IS CLEARLY SEEN IN THE SATELLITE IMAGERY AS THE
TOPS OF THE CONVECTION IN THE LOW BLOW OFF TO THE WEST AT REGULAR
INTERVALS. IN ITS FAVOR...GASTON`S REMNANT LOW IS EXPECTED TO MOVE
OVER SLIGHTLY WARMER WATER IN THE NEXT 12 TO 24 HOURS AND
POSSIBLY INTO A MOISTURE PLUME FROM THE SOUTH OVER THE LESSER
ANTILLES. THIS PLUME IS PRESENTLY SPREADING SHOWERS OVER A WIDE
SWATH OF THE WINDWARD AND LEEWARD ISLANDS BUT WILL MOVE OVER
PUERTO RICO AND THE U.S. VIRGIN ISLANDS IN THE NEXT 9 TO 21
HOURS. THUS THERE IS STILL A POSSIBILITY THAT GASTON WILL BECOME
RE-INVIGORATED...AND SHOULD IT DO SO...IT IS NOT SO LIKELY TO
REMAIN SO FAR SOUTH OF THE AREA...AND COULD STILL PASS DIRECTLY
OVER THE AREA...THEREFORE ALL INTERESTED PARTIES SHOULD CONTINUE
TO MONITOR THE PROGRESS AND DEVELOPMENT OF THIS LOW.
HOWEVER AT THIS TIME AM CONSIDERING THE UKMET TO BE THE MODEL
THAT BEST DEPICTS WHAT THE LOW WILL DO...AND THE ONE THAT WAS BEST
INITIALIZED WITH THE APPARENT CONDITIONS OF THE REMNANT LOW.

FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS THIS MEANS INCREASING
WIND AHEAD OF THE LOW...WHICH IS EXPECTED TO CONTINUE ON A WESTWARD
COAST AND FLIRT WITH TROPICAL STORM STATUS...AS IT PASSES THROUGH
THE CARIBBEAN SEA TO THE SOUTH OF OUR FORECAST AREA. WE WILL
STILL BE IN THE STRONGER NORTHERN HEMISPHERE OF ITS INFLUENCE
WITH SHOWERS AND THUNDERSTORMS LIKELY AND WINDS THAT COULD REACH
20 TO 30 KNOTS IN OUR MARINE ZONES TUESDAY NIGHT AND WEDNESDAY.
THUS HAVE MASSAGED THE WIND GRIDS BEFORE AND AFTER THIS PERIOD TO
MORE CLOSELY RESEMBLE THE WIND FLOW PATTERN LEADING UP TO THE
PASSAGE OF A CLOSED LOW TO OUR SOUTH AND KEPT WINDS IN THE
OVERNIGHT PERIOD ON TUESDAY UNCHANGED...SINCE...FOR US...THE
PASSAGE OF A STRONG TROPICAL WAVE ABOUT 180 MILES SOUTH WILL
CLOSELY RESEMBLE THE PASSAGE OF A CLOSED LOW ABOUT 225 MILES
SOUTH. THIS SYSTEM IN EITHER FORM SHOULD BRING NUMEROUS SHOWERS
WITH SIGNIFICANT RAINS TUESDAY NIGHT AND WEDNESDAY...AND...DEPENDING
ON THE EXACT CONFIGURATION OF THE BANDS OF THE LOW AS IT LEAVES
THE LOCAL AREA...SHOWERS COULD LINGER ON THROUGH THURSDAY.

WINDS AND MOISTURE PATTERNS ARE UNREMARKABLE AFTER FRIDAY OR
SATURDAY WHEN MOISTURE BANDS LEAVE THE AREA. THE MODELS DO
DEVELOP ANOTHER SYSTEM NO LATER THAN FRIDAY 10 SEPTEMBER...POSSIBLY
FROM THE SYSTEM JUST LEAVING THE AFRICAN COAST NOW...WITH TOPS
NOTED AT MINUS 86 DEGREES IN THE 05/18Z SATELLITE PASS. THIS SYSTEM
IS NOT EXPECTED TO ARRIVE BEFORE WEDNESDAY...15 SEPTEMBER... AND
ITS TRACK IS QUITE UNCERTAIN AT THIS TIME. THE GFS TAKES IT NORTH
OF 20 NORTH BEFORE REACHING 50 WEST...BUT THE ECMWF LEAVES IT ON A
WEST NORTHWEST COURSE FOR GUADELOUPE. AND...IF THERE ARE
DEVELOPMENTS IN THE GULF OF MEXICO...IT WON`T EVEN BE THE NEXT
NAMED STORM!

[HurricaneMaster_PR]

Convection increasing once again near the center of circulation. Lets see how much it is going to expand..

http://www.ssd.noaa.gov/goes/east/carb/loop-avn.html

[CalmBeforeStorm]

Here is tonights updated discussion by the San Juan NWS.

Blown Away, I know you like these long discussions from San Juan.

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
947 PM AST SUN SEP 5 2010

.UPDATE...WINDS HAVE SHIFTED MORE EAST SOUTHEAST FROM THE 12Z
SOUNDING AND PRECIPITABLE WATER HAS INCREASED FROM 24 HOURS AGO
BUT INCREASED FROM 12 HOURS AGO. SHOWERS AND THUNDERSTORMS
CONTINUE IN THE ATLANTIC AND CARIBBEAN WATERS WITH A FEW SHOWER
INCURSIONS OVER CABO ROJO AND NORTHEAST PUERTO RICO. OTHERWISE ALL
SHOWERS OVER LAND HAVE DISSIPATED. ONE SHOWER WAS NOTED OVER THE
BEACHES IN SOUTHERN SAINT CROIX AND OVER THE WATERS THERE.


&&

.DISCUSSION...THE 05/18Z MODEL RUNS CONTINUE BRINGING THE REMNANT LOW
OF GASTON ACROSS THE CARIBBEAN WATERS SOUTH OF PUERTO RICO
TUESDAY NIGHT AND WEDNESDAY MORNING. ALTHOUGH DIFFICULT TO
TRACK...THIS LOW APPEARS TO BE MOVING AT ABOUT 9 TO 12 KNOTS DUE
WEST AND WOULD PASS SOUTH OF PUERTO RICO IN ABOUT THE SAME TIME
FRAME IF IT WERE TO CONTINUE UNCHANGED. THE NAM CARRIES THE LOW
JUST SOUTH OF PUERTO RICO IN A SOMEWHAT SPLINTERED FORM. THE GFS
CARRIES THE LOW ACROSS AS AN OPEN WAVE ABOUT 180 MILES SOUTH OF
SAN JUAN AT 08/06Z. THE ECMWF 12Z RUN LOSES THE LOW BUT SHOWS A
WEAK TURNING IN AN OPEN WAVE AT ABOUT 240 MILES SOUTH OF SAN JUAN
ALSO AROUND 08/06Z. THE UKMET 12Z RUN BRINGS THE LOW ACROSS
VIRTUALLY UNCHANGED...OR SLIGHTLY STRONGER...ABOUT 225 MILES SOUTH
OF SAN JUAN AT 08/02Z. THE FORMER MODELS HAVE WINDS AT 850 MB
WHICH RANGE FROM 10 TO 25 KNOTS...WHILE THE UKMET SHOWS WINDS UP
TO 35 KNOTS ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS ALSO AT
850 MB.

THE REMNANT LOW...CURRENTLY LOCATED ABOUT 860 MILES EAST
SOUTHEAST OF SAN JUAN...HAS BEEN STRUGGLING AGAINST A NUMBER OF
FACTORS WHICH MAY ULTIMATELY PROVE TO BE OVERWHELMING. GASTON HAS
BEEN NEARLY CUT OFF FROM ITS MOISTURE STREAM IN THE ITCZ AND IS
NEARLY ENCLOSED BY DRIER AIR AS EVIDENCED BY SHARPLY DEFINED
OUTFLOW BOUNDARIES MOVING EAST OUT OF THE MAIN CONVECTION. THE
AIR TO OUR EAST AHEAD OF THE LOW IS ALSO A LITTLE DRIER. WINDS AT
250 MB CONTINUE TO BE FAIRLY STRONG...VARYING FROM 25 TO 40
KNOTS. THIS SHEAR IS CLEARLY SEEN IN THE SATELLITE IMAGERY AS THE
TOPS OF THE CONVECTION IN THE LOW BLOW OFF TO THE WEST AT REGULAR
INTERVALS. IN ITS FAVOR...GASTON`S REMNANT LOW IS EXPECTED TO MOVE
OVER SLIGHTLY WARMER WATER IN THE NEXT 12 TO 24 HOURS AND
POSSIBLY INTO A MOISTURE PLUME FROM THE SOUTH OVER THE LESSER
ANTILLES. THIS PLUME IS PRESENTLY SPREADING SHOWERS OVER A WIDE
SWATH OF THE WINDWARD AND LEEWARD ISLANDS BUT WILL MOVE OVER
PUERTO RICO AND THE U.S. VIRGIN ISLANDS IN THE NEXT 9 TO 21
HOURS. THUS THERE IS STILL A POSSIBILITY THAT GASTON WILL BECOME
RE-INVIGORATEDWINDS AND MOISTURE PATTERNS ARE UNREMARKABLE AFTER FRIDAY OR
SATURDAY WHEN MOISTURE BANDS LEAVE THE AREA. THE MODELS DO
DEVELOP ANOTHER SYSTEM NO LATER THAN FRIDAY 10 SEPTEMBER...POSSIBLY
FROM THE SYSTEM JUST LEAVING THE AFRICAN COAST NOW...WITH TOPS
NOTED AT MINUS 86 DEGREES IN THE 05/18Z SATELLITE PASS. THIS SYSTEM
IS NOT EXPECTED TO ARRIVE BEFORE WEDNESDAY...15 SEPTEMBER... AND
ITS TRACK IS QUITE UNCERTAIN AT THIS TIME. THE GFS TAKES IT NORTH
OF 20 NORTH BEFORE REACHING 50 WEST...BUT THE ECMWF LEAVES IT ON A
WEST NORTHWEST COURSE FOR GUADELOUPE. AND...IF THERE ARE
DEVELOPMENTS IN THE GULF OF MEXICO...IT WON`T EVEN BE THE NEXT
NAMED STORM!

That kind of mirrors my feelings on Gaston. If he stays weak I expect him to take a path through the Carribean where he might reorganize in the western side. If he strengthens at all before the islands he will be influenced by the trough forecast to be off the east coast in four days and will ride above the islands.

[latitude_20]

I love that long discussion. Very helpful. I do see the moisture plume on vapor blowing up over the Lesser Antilles, as well as another plume feeding up over PR, the DR/Haiti. So in other words, he could grab hold of this and strengthen?

[Florida1118]

Looks like no upgrade for Gaston...

[cycloneye]

Looks like no upgrade for Gaston...

They may wait for the plane that will fly to the system tommorow afternoon to then upgrade or not depending on what they find,unless it organizes overnight rapidly.

[Florida1118]

Looks like no upgrade for Gaston...

They may wait for the plane that will fly to the system tommorow afternoon to then upgrade or not depending on what they find,unless it organizes overnight rapidly.

Oh ya forgot about the Schedule. Seems Reasonable except for the Virgin Islands and Lesser Antilies that if this were a storm, warnings/watches would need to be put up quickly.

[supercane]

Latest ASCAT still shows a low:

[HURAKAN]

Latest

[Bailey1777]

ir showing some high tops IMO this may be the comeback starting. i stand by the no recurve and my only question is where in the gom does it go.