[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED OCT 19 2011

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1745 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM NEAR 19N30W TO 8N41W MOVING W AT
8-12 KT. WAVE IS WELL DEFINED IN THE LOW LEVEL CLOUD FIELD AND
IS EMBEDDED WITHIN A DEEP SURGE OF MOISTURE DEPICTED ON THE
TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF SCATTERED MODERATE
TO STRONG CONVECTION ARE FROM 7N-20N BETWEEN 25W-42W.

TROPICAL WAVE IS ANALYZED IN THE CENTRAL TROPICAL ATLC FROM
13N49W TO 6N52W MOVING W 10-15 KT. WAVE IS WELL DEFINED AND IS
EMBEDDED WITHIN A MOISTURE SURGE DEPICTED ON TOTAL PRECIPITABLE
WATER IMAGERY. CLUSTERS OF SCATTERED MODERATE TO STRONG
CONVECTION ARE FROM 5N-13N BETWEEN 42W-54W.

THE TROPICAL WAVE THAT WAS MOVING ACROSS THE CARIBBEAN OVER THE
PAST FEW DAYS HAS LOST ITS WAVE QUALITIES AND STRUCTURE.
THEREFORE...A REMNANT TROUGH AXIS WAS LAST ANALYZED FROM 16N73W
TO 10N74W WITH NO CONVECTION IN THE VICINITY OF ITS AXIS.

...THE ITCZ/THE MONSOON TROUGH...

THE OCEANIC MONSOON TROUGH HAS BEEN DISRUPTED DUE TO THE LARGE
CYCLONIC WIND FIELD ASSOCIATED WITH THE TROPICAL WAVES. THE
OTHER PORTION OF IT REMAINS INLAND OVER NRN AFRICA. CONSEQUENTLY
...THE ITCZ IS DISRUPTED BY THE PRESENCE OF THESE TROPICAL
WAVES. FOR INFORMATION REGARDING CONVECTION IN THIS REGION SEE
TROPICAL WAVES DISCUSSION ABOVE.

...DISCUSSION...

THE GULF OF MEXICO...
THE AFOREMENTIONED COLD FRONT FROM PREVIOUS DISCUSSIONS IS NOW
MOVING ACROSS THE FLORIDA PENINSULA AND THE FAR SE GULF INTO THE
ATLANTIC BASIN...ANALYZED ENTERING THE DISCUSSION AREA FROM JUST
S OF TAMPA BAY TO THE FAR NE CORNER OF THE YUCATAN PENINSULA.
THE SURFACE PRESSURE GRADIENT BEHIND THE FRONT IS FAIRLY TIGHT
...GENERATING NNE FLOW 15-25 KT GUSTING TO NEAR GALE FORCE
CRITERIA. SCATTERED HEAVY SHOWERS AND THUNDERSTORMS...SOME
SEVERE...ARE AHEAD OF THE FRONT UP TO 110 NM. MOST OF IT IS
MOVING ACROSS THE FLORIDA STRAITS. HOWEVER...DOPPLER RADAR
IMAGERY INDICATED THE MOST CONVECTIVE AREA IS CURRENTLY MOVING
ACROSS THE FLORIDA KEYS AND THE IMMEDIATE COAST OF THE SOUTHERN
TIP OF THE PENINSULA. THE FRONT AND ASSOCIATED CONVECTION IS
EXPECTED TO MOVE OUT OF THE AREA DURING THE AFTERNOON HOURS WITH
SOME SHOWERS LINGERING THROUGH THE NEXT 24 HOURS. HIGH PRESSURE
WILL BUILD OVER THE ENTIRE AREA GULF IN THE WAKE OF THE FRONT
THROUGH SATURDAY.

THE CARIBBEAN SEA...
STRONG SHOWERS AND THUNDERSTORMS CONTINUE TO AFFECT THE FAR NW
BASIN AND YUCATAN CHANNEL W OF 83W...ASSOCIATED TO THE COLD
FRONT MENTIONED IN THE ATLC AND GULF OF MEX DISCUSSIONS. SIMILAR
ACTIVITY COVERS THE SW BASIN RELATED TO MONSOONAL FLOW ACROSS
THIS AREA...GENERATING SCATTERED MODERATE TO HEAVY SHOWERS S OF
15N W OF 75W. OTHERWISE...FAIR WEATHER CONDITIONS PREVAIL
ELSEWHERE ACROSS THE AREA...AS A BROAD UPPER ANTICYCLONE DRAWS
DRY/SUBSIDENT AIR ALOFT SUPPRESSING DEEP CONVECTION ACROSS THE
AREA. THE FRONT IS EXPECTED TO FULLY ENTER THE NW CARIBBEAN THIS
AFTERNOON...GENERATING SIMILAR CONVECTION TO THE COASTAL WATERS
FROM HONDURAS TO COLOMBIA OFF TO 180 NM OFFSHORE W OF 75W. AS
THE COOLER/DRYER AIRMASS MIXES WITH THE TROPICAL AIRMASS...THE
FRONT WILL BECOME NEARLY STATIONARY DURING THE NEXT 48 HOURS.

THE ATLANTIC OCEAN...
A DEEP LAYER TROUGH/CUT OFF LOW SWINGS ACROSS THE ERN CONUS
SUPPORTING A VIGOROUS COLD FRONT SOON TO BE MOVING OFF THE ERN
SEABOARD. PRE FRONTAL CONVECTION IS ALREADY IMPACTING THE FAR
WRN ATLC SINCE THE EARLY HOURS OF THE DAY...AND CAN BE TRACKED
ALONG THE PRE FRONTAL TROUGH ANALYZED ALONG 30N80W TO ACROSS THE
SOUTHERN FLORIDA PENINSULA AND STRAITS INTO WRN CUBA. SCATTERED
MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ARE MOSTLY W OF 75W.
THE SURFACE PRESSURE GRADIENT AHEAD OF THE FRONT CONTINUES TO
BECOME COMPACTED LEADING TO GALE FORCE WINDS AND SEAS 9 TO 14 FT
EXPECTED TO DEVELOP DURING THE AFTERNOON HOURS. THE FRONT AND
ASSOCIATED CONVECTION IS EXPECTED TO CONTINUE TO PROGRESS
EASTWARD DURING THE NEXT 48 HOURS. A BROAD UPPER ANTICYCLONE
COVERS THE REST OF THE WRN ATLC AHEAD OF THE FRONTAL CONVECTION
...AND A BROAD SURFACE RIDGE OF HIGH PRESSURE ANCHORED N OF THE
DISCUSSION AREA ARE KEEPING FAIR CONDITIONS ELSEWHERE ACROSS THE
CENTRAL AND ERN BASINS N OF 20N.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$

GARCIA




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