ATL: Ex-Tropical Storm GASTON - Discussion

[Gustywind]

000
AXNT20 KNHC 051203
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN SEP 05 2010

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1145 UTC.

...SPECIAL FEATURES...

A 1009 MB LOW...REMNANT OF GASTON...IS ABOUT 700 NM E OF THE
LESSER ANTILLES NEAR 17N49W MOVING W NEAR 10 KT. SATELLITE
IMAGERY INDICATES A LOW LEVEL SWIRL WITH SMALL CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION TO THE W FROM
15N-18N BETWEEN 50W-54W. ALTHOUGH ACTIVITY IS CURRENTLY
LIMITED...ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR
RE-DEVELOPMENT OF THIS SYSTEM AND A TROPICAL DEPRESSION COULD
RE-FORM IN THIS AREA LATER TODAY OR MONDAY. THERE IS A HIGH
CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE AGAIN DURING
THE NEXT 48 HOURS.
A $$
PAW

[BigA]

Looks a good deal better than when I went to bed. Let's see if the convection persists and continues to organize.

[AtlanticWind]

As I said last night watch out when this system passes 50 west . May already refiring this morning, small systems like this can spin up real quick and the islands and PR should keep a close eye on Gaston.

[cycloneye]

12z Best Track

AL, 09, 2010090512, , BEST, 0, 168N, 500W, 25, 1009, LO

Moving westward.

[OURAGAN]

I begin to believe the west southwest track to 265°W

[cycloneye]

LATCUR = 16.8N LONCUR = 50.0W DIRCUR = 270DEG SPDCUR = 11KT

[Recurve]

Some convection growing -- near the center?

[Macrocane]

Just as we thought, now that it passed 50 W the convection is refiring, if it mantains the convection maybe we will see an 80% or 90% in the next TWO.

[HURAKAN]

latest



Fiona when upgraded to tropical storm

[gatorcane]

Convection is on the increase. Models are definitely having a tough time with this one. They clearly are not certain how the TUTT and land interaction are going to play a role with the long-term evolution with this system. The hurricane models seem to favor development while globals have backed off the past few runs. They may be the ones having difficulties with the synoptics as conditions continue to improve for redevelopment. Currently there is some light easterly shear over the system that should diminish over the next day or so while moisture continues to increase.

[AtlanticWind]

Convection is on the increase. Models are definitely having a tough time with this one. They clearly are not certain how the TUTT and land interaction are going to play a role. The hurricane models seem to favor development while globals have backed off the past few runs. They may be the ones having difficulties with the synoptics as conditions continue to improve for redevelopment. Currently there is some light easterly shear over the system.

Globals some times have trouble picking up small systems as this one seems to be.

[Recurve]

Don't know if it's mid or low level but certainly looks like a closed low to my untrained eye at the coords given, 18.8 n 50.0 W. From cloud appearance, shear seems to be low to non-existent. Mainly atmospheric moisture may be lacking and lack of upper divergence (?).

BTW, the system is 1,770 miles from S Fla and at current speed of about 11-12 knots, if there's a Gaston and it tracks directly, it's 138 hours away, which makes the timeframe Friday-Saturday for this area.

[ericinmia]

Really starting to re-fire...

http://www.ssd.noaa.gov/goes/east/carb/loop-rb.html
May not be as dead as sooo many were arguing yesterday!

[Gustywind]

From Crown Weather Discussion
http://www.crownweather.com/?page_id=325
Tropical Weather Discussion
Issued: Sunday, September 5, 2010 905 am EDT/805 am CDT


Ex-Tropical Depression Gaston:
We continue to closely monitor the area of disturbed weather that was once Gaston. This system is currently located about 750 miles east of the Leeward Islands. Given the fact that environmental conditions are favorable for regeneration, this system will be closely monitored. There is a high degree of uncertainty on what this system may do over the next several days. Satellite imagery this morning showed a well defined low level circulation, however, there is a limited amount of deep convection associated with this system. This is likely due to the entrainment of dry air.

The synoptic forecast ahead of this system calls for an upper level trough of low pressure to back away over the next few days and for Ex-Gaston to remain in an area of fairly low wind shear. This system will also be tracking into increasingly warmer ocean waters, especially west of 58 West Longitude. This alone indicates that regeneration into a tropical cyclone seems likely over the next couple of days.

The one huge fly in the ointment, however, is the fact that the global model guidance has been all over the place with this system. The GFS model waffles back and forth between a weak area of low pressure and a significant hurricane in just 48 hours from now. The NHC track model guidance continues to indicate significant strengthening and a track that would take this system across the northern Leeward Islands during Tuesday and to just south of Puerto Rico on Wednesday and very near Haiti by the end of the week. As for the intensity guidance from the NHC models, the latest SHIPS guidance forecasts a moderate tropical storm by Tuesday morning and a hurricane by Tuesday night. The LGEM model forecasts Ex-Gaston to become a moderate strength tropical storm by Tuesday, a hurricane by Wednesday and a major hurricane by Thursday.

Given that this is a long holiday weekend, all emergency management officials, residents and vacationers in the Leeward Islands, Virgin Islands, Puerto Rico and Hispaniola should closely monitor this system and be ready to take quick action, should it become necessary. Those of you with friends and family in the Leeward Islands, Virgin Islands, Puerto Rico and Hispaniola, give them a heads up and let them know that there is a tropical system that they should closely monitor and that it could affect the northern Leeward Islands on Tuesday (just 48 hours from now!), Puerto Rico on Wednesday and Hispaniola by Thursday and Friday.

Disclaimer: All forecasts herein are made to the best ability of the forecaster. However, due to standard forecasting error, these forecasts cannot be guaranteed. Any action or inaction taken by users of this forecast is the sole responsibility of that user.

[Sanibel]

Such small weak systems heading right into the teeth of a ULL normally spells doom (for the system).

[AtlanticWind]

Such small weak systems heading right into the teeth of a ULL normally spells doom (for the system).

Ull moving west ,should not be a problem for this system.

[Sanibel]

Ull moving west ,should not be a problem for this system.

I don't see that on the water vapor loop (WV):


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

[HURAKAN]

latest

[ROCK]

Ull moving west ,should not be a problem for this system.

I don't see that on the water vapor loop (WV):


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

I do...its moving west in tandem with Gaston....PR discussion said it all....

[Sanibel]

My eye catches the ULL nudging west but Gaston overtaking it.