[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181741
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE OCT 18 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
1735 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM CAPE VERDE ISLANDS NEAR 17N24W TO
11N34W W AT 10-15 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 MOSTLY OVER THE NRN
HALF OF THE WAVE AXIS FROM 13N-20N BETWEEN 20W-30W.

TROPICAL WAVE IS ANALYZED IN THE CENTRAL TROPICAL ATLC FROM
12N45W TO 5N50W MOVING W 10-15 KT. WAVE IS WELL DEFINED AND IS
AT THE LEADING EDGE OF A MOISTURE SURGE AS DEPICTED ON THE TOTAL
PRECIPITABLE WATER IMAGERY. CLUSTERS OF SCATTERED MODERATE TO
STRONG CONVECTION ARE FROM 7N-12N BETWEEN 43W-50W.

TROPICAL WAVE IS ANALYZED OVER THE CENTRAL CARIBBEAN FROM 17N68W
TO 10N70W MOVING 10-15 KT. WAVE IS BEING SUPPRESSED BY A DRY AND
SUBSIDENT AIRMASS ALOFT INTRUDING ACROSS THE ERN AND N CENTRAL
BASIN ON WATER VAPOR IMAGERY. WEAK CYCLONIC TURNING IS OBSERVED
ON THE LOW LEVEL CLOUD FIELD ALONG THE SRN EXTENSION OF THE WAVE
AXIS. NO SIGNIFICANT CONVECTION IS AROUND THIS SYSTEM.

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

DUE TO THE LARGE CYCLONIC WIND FIELD ASSOCIATED TO THE TROPICAL
WAVES...THE OCEANIC MONSOON TROUGH IS DISRUPTED AND THE OTHER
PORTION OF IT REMAINS INLAND OVER NRN AFRICA. CONSEQUENTLY...THE
ITCZ IS DISRUPTED BY THE PRESENCE OF THESE TROPICAL WAVES.
NEVERTHELESS... AN AREA OF SCATTERED WEAK CONVECTION IS FROM
4N-10N BETWEEN 15W-22W.

...DISCUSSION...

GULF OF MEXICO...
THE MAIN AREA OF ACTIVE WEATHER CONTINUES TO FOCUS AROUND THE
SET OF SURFACE LOWS IMPACTING THE SE GULF. THE MAIN CIRCULATION
IS ANALYZED AS A 1003 MB LOW NEAR 26N88W. THE WEAKER/DISSIPATING
CIRCULATION HAS STAYED WOBBLING OVER THE NORTHERN COASTAL WATERS
OF THE YUCATAN PENINSULA NEAR 22N88W. A SURFACE TROUGH CROSSES
THE MAIN LOW FROM 30N85W TO THE LOW CENTER...THEN S TO NEAR
24N88W. THE CIRCULATION AROUND THIS SYSTEM COVERS A GREAT
PORTION OF THE BASIN E OF 93W...RAGING FROM 15 KT TO NEAR GALE
FORCE CRITERIA S OF 28N E OF 91W. DESPITE THE LOCATION OF THESE
SURFACE FEATURES ...AN UPPER LEVEL SHORTWAVE/TROUGH IS DRIVING
THE CONVECTION TO THE EAST OF THE LOWS E OF 87W. SCATTERED HEAVY
SHOWERS AND THUNDERSTORMS ARE IN THIS REGION...WITH THE
POSSIBILITY OF STRONG GUSTY OUT FLOW BOUNDARIES AND WATER
SPOUTS. AS THE SYSTEM CONTINUES TO TRACK NE...LOCALLY HEAVY
RAINFALL...GUSTY WINDS... AND POSSIBLE SEVERE WEATHER OVER THE
FLORIDA KEYS...THE FLORIDA PENINSULA...SOUTHERN GEORGIA...AND
COASTAL SECTIONS OF THE CAROLINAS ARE EXPECTED OVER THE NEXT DAY
OR SO. FOR INFORMATION SPECIFIC TO YOUR AREA PLEASE SEE
STATEMENTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE
FORECAST OFFICE.

ANOTHER AREA OF SIGNIFICANT WEATHER IS OCCURRING OVER THE NW
GULF AS A COLD FRONT MOVES OFF THE TEXAS COAST RAPIDLY WITH NEAR
GALE FORCE WINDS IN ITS WAKE...AS OBSERVED FROM BUOYS AND NOAA
SHIPS. CURRENTLY THE FRONT EXTENDS FROM THE COAST OF LOUISIANA
TO THE MEXICO COAST ALONG 29N91W TO 24N98W. A LINE OF HEAVY
SHOWERS AND THUNDERSTORMS DEFINE THE FRONTAL BOUNDARY ON VISIBLE
SATELLITE IMAGERY. SHORT RANGE COMPUTER MODELS SUGGEST THIS
FRONT WILL CONTINUE TO MOVE QUICKLY ACROSS THE AREA. IN THE MEAN
TIME ...A SECOND PUSH OF DRYER AND COOLER AIRMASS WILL ENTER THE
NW BASIN WITH GALE WINDS EXPECTED TO DEVELOP OVER THE FAR SW
BASIN AND BAY OF CAMPECHE. HIGH PRESSURE WILL BUILD OVER THE
ENTIRE AREA GULF IN THE WAKE OF THE FRONT THROUGH SATURDAY.

CARIBBEAN SEA...
THE BROAD AREA OF LOW PRESSURE OVER THE GULF OF MEXICO COVERS
THE FAR NW CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS N OF 19N W OF 83W. OTHERWISE...MOST OF THE
CARIBBEAN BASIN IS EXPERIENCING FAIR WEATHER CONDITIONS THIS
AFTERNOON...EXCEPT FOR THE FAR SW BASIN. THE BENIGN WEATHER IS
OBSERVED AS A DRY AND SUBSIDENT AIRMASS ALOFT INTRUDES ACROSS
THE ERN AND N CENTRAL BASIN SUPPRESSING DEEP CONVECTION. WHILE
THE CONVECTION OVER THE FAR NW BASIN IS RELATED TO THE SYSTEM
OVER THE GULF OF MEXICO...THE CONVECTION OVER THE SW BASIN IS
RELATED TO MONSOONAL FLOW ACROSS THIS AREA GENERATING SCATTERED
HEAVY SHOWERS AND ISOLATED THUNDERSTORMS S OF 15N W OF 75W. A
TROPICAL WAVE MOVES ACROSS THE CENTRAL BASIN WITHOUT ANY
SIGNIFICANT CONVECTION...SEE ABOVE FOR MORE DETAILS. OTHERWISE
...LIGHT EASTERLY TRADE FLOW PREDOMINATES ACROSS THE AREA...
BECOMING SSE W OF 75W IN RESPONSE OF THE LOWER PRESSURES RELATED
TO THE GULF OF MEXICO SYSTEM. THE COLD FRONT CURRENTLY MOVING
ACROSS THE GULF WILL MOVE INTO THE NW CARIBBEAN TONIGHT THEN BE
ABSORBED BY A STRONGER COLD FRONT THAT PUSHES INTO THE NW
CARIBBEAN BY WED EVENING. THE TROPICAL WAVE WILL WEAKEN OVER THE
CENTRAL CARIBBEAN LATE WED NIGHT.

ATLANTIC OCEAN...
SSE 10-20 KT SURFACE FLOW COVERS THE WRN BASIN DRAWING LOW LEVEL
MOISTURE NOTICED ON TOTAL PRECIPITABLE WATER PRODUCT. THESE LOW
LEVEL CONDITIONS ALONG WITH A DIFFLUENT ENVIRONMENT ALOFT IS
GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS W OF
73W. AN ELONGATED UPPER LEVEL CIRCULATION CENTERED NEAR 20N50W
AND AN UPPER LEVEL RIDGE CENTERED OVER ERN CUBA IS DRAWING A DRY
AIRMASS INTO THE ERN AND N CENTRAL CARIBBEAN. TO THE E OF THIS
CIRCULATION...AN UPPER LEVEL CYCLONIC CIRCULATION IS NEAR 30N30W
AND ITS SURFACE REFLECTION IS CENTERED AROUND A WEAK 1016 MB LOW
NEAR 30N37W. THE CONVECTION ASSOCIATED TO THIS SYSTEM IS WELL
REMOVED TO THE E OF THE SURFACE LOW...N OF 27N BETWEEN 23W-32W.
THE BROAD LOW PRESSURE OVER THE GULF OF MEXICO WILL TRACK NE
AHEAD OF A STRONG COLD FRONT THAT WILL MOVE OFF THE NE FLORIDA
COAST WED EVENING WITH CONVECTION. BY THURSDAY THE FRONT WILL
WEAKEN AND BECOME STATIONARY. WEAK HIGH PRESSURE WILL BUILD
ACROSS THE AREA BEHIND THE FRONT.

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

$$

GARCIA




This weather bulletin was brought to you by:
www.nashvilleweather.net