[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 131801
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT OCT 13 2012

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
1715 UTC.

...SPECIAL FEATURES...

TROPICAL STORM RAFAEL IS CENTERED NEAR 16.5N 63.9W AT 13/1800
UTC OR ABOUT 87 NM SE OF ST. CROIX MOVING N AT 8 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND
SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE LATEST NHC INTERMEDIATE
PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32 KNHC
AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC. AN UPPER RIDGE TO THE E OF THE LESSER
ANTILLES IS ENHANCING THE DEEP CONVECTION AND DRAWING THE
CONVECTION E OF THE LESSER ANTILLES. SCATTERED/NUMEROUS STRONG
CONVECTION IS FROM 13N-17N BETWEEN 60W-64W INCLUDING PORTIONS OF
THE WINDWARD AND LEEWARD ISLANDS. SCATTERED MODERATE/STRONG
CONVECTION COVERS THE AREA FROM 9N-13N BETWEEN 59W-60W AND
WITHIN 90 NM OF LINE FROM 15N57W 19N61W TO 19N64W INCLUDING
PORTIONS OF THE LEEWARD AND VIRGIN ISLANDS.

TROPICAL DEPRESSION PATTY WAS DOWNGRADED AT 13/1500 UTC TO
POST-TROPICAL CYCLONE. THE REMNANTS OF PATTY IS CENTERED NEAR
24.8N 72.6W AT 13/1500 UTC OR ABOUT 191 NM E-NE OF THE CENTRAL
BAHAMAS MOVING W-SW AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 1010 MB. MAXIMUM SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO
35 KT. THIS IS THE LAST ADVISORY ISSUED BY THE NATIONAL
HURRICANE CENTER. THE AREA IS VOID OF ANY DEEP CONVECTION WITH
POSSIBLE ISOLATED SHOWERS WITHIN 60/75 NM OF LINE FROM 26N70W TO
24N74W.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM THE CAPE VERDE ISLANDS NEAR 17N30W TO
12N33W MOVING W NEAR 15 KT. WAVE IS EMBEDDED WITHIN A SURGE OF
DEEP MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER
IMAGERY AND AT THE BASE OF AN UPPER TROUGH. SCATTERED MODERATE/
STRONG CONVECTION FROM 11N-15N BETWEEN 29W-34W. SCATTERED
MODERATE CONVECTION IS WITHIN 120 NM OF LINE FROM 15N30W TO
19N26W.

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

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL
ATLC NEAR 13N16W TO 12N20W WHERE THE ITCZ AXIS BEGINS S OF THE
TROPICAL WAVE NEAR 11N32W CONTINUING ALONG 10N36W TO 10N56W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
WITHIN 120 NM OF LINE FROM 14N25W ACROSS THE ITCZ TO 4N33W...
WITHIN 120 NM N OF THE ITCZ BETWEEN 34W-54W...AND WITHIN 180 NM
S OF THE ITCZ BETWEEN 38W-50W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE COVERS THE GULF THIS AFTERNOON W OF 86W
EXTENDING FROM ACROSS MEXICO INTO THE GULF NEAR TAMPICO TO OVER
THE N GULF COAST NEAR ALABAMA/MISSISSIPPI. AN UPPER TROUGH
COVERS THE REMAINDER OF THE GULF E OF 86W WITH THE TROUGH AXIS
IN THE W ATLC. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
WITHIN 30 NM ALONG THE COAST OF MEXICO BETWEEN VERACRUZ LAGUNA
MORALES. THE SURFACE RIDGE HAS BUILT OVER THE GULF ANCHORED OVER
PENNSYLVANIA WITH DRY STABLE UPPER AIR DOMINATING MOST OF THE
GULF. THUS...THE REMAINDER OF THE GULF IS UNDER MOSTLY CLEAR
SKIES THIS AFTERNOON. HIGH PRESSURE WILL SHIFT E ON MON AND TUE.
A COLD FRONT WILL APPROACH THE TEXAS COAST BY LATE WED.

CARIBBEAN SEA...
THE PRIMARY CONCERN THIS AFTERNOON IS TROPICAL STORM RAFAEL IN
THE E CARIBBEAN...SEE SPECIAL FEATURES ABOVE. THE NARROW UPPER
TROUGH OVER THE E GULF OF MEXICO EXTENDS S OVER THE NW CARIBBEAN
ACROSS CENTRAL CUBA TO E HONDURAS GENERATING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS FROM 15N-18N BETWEEN 79W-86W TO INLAND
OVER HONDURAS. SCATTERED SHOWERS WITH POSSIBLE ISOLATED
THUNDERSTORMS ARE FROM OVER JAMAICA TO INLAND ACROSS CUBA
BETWEEN 74W-78W. AN UPPER RIDGE EXTENDS ACROSS THE S CARIBBEAN
FROM THE W TROPICAL ATLC ACROSS THE WINDWARD ISLANDS TO S
NICARAGUA COVERING THE REMAINDER OF THE BASIN. THIS UPPER RIDGE
IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS WITHIN 75/90 NM ALONG THE COAST OF
NICARAGUA. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN
FROM COLOMBIA NEAR 9N75W ALONG 10N80W THEN ACROSS COSTA RICA
INTO THE E PACIFIC REGION NEAR 10N83W GENERATING CLUSTERS OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 11N BETWEEN
75W-82W. THIS IS LEAVING THE CENTRAL CARIBBEAN WITH FAIR WEATHER
THIS AFTERNOON. T.S. RAFAEL IS EXPECTED TO MOVE NNW ACROSS THE
CARIBBEAN TODAY THEN ACROSS THE VIRGIN ISLANDS THIS EVENING AND
TONIGHT WHILE SLOWLY INTENSIFYING. STRONG NE WINDS WILL CONTINUE
ACROSS THE NW CARIBBEAN THROUGH TONIGHT AS STRONG HIGH PRESSURE
BUILDS OVER E CONUS. WINDS AND SEAS WILL DIMINISH ACROSS THE
ENTIRE CARIBBEAN SUN THROUGH WED.

ATLANTIC OCEAN...
THE REMNANTS OF PATTY REMAINS NE OF THE CENTRAL BAHAMA ISLANDS
THIS AFTERNOON...SEE SPECIAL FEATURES ABOVE. THE UPPER TROUGH
OVER THE E GULF OF MEXICO AND THE NW CARIBBEAN EXTENDS OVER THE
W ATLC N OF 27N W OF 70W THEN NARROWS AS IT CROSSES CUBA INTO
THE NW CARIBBEAN WITH STRONG SUBSIDENCE AND DRY STABLE AIR
ALOFT. THE UPPER TROUGH IS SUPPORTING A COLD FRONT N OF THE
DISCUSSION AREA WITH A STATIONARY FRONT EXTENDING FROM 32N63W TO
28N69W AND GENERATING SCATTERED SHOWERS WITH POSSIBLE ISOLATED
THUNDERSTORMS WITHIN 120/150 NM E OF FRONT. SCATTERED SHOWERS
AND POSSIBLE ISOLATED THUNDERSTORMS ARE ALSO FROM OVER THE
BAHAMA ISLANDS TO CUBA BETWEEN 72W-79W. AN UPPER LOW IS IN THE E
ATLC CENTERED NEAR 21N36W GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 20N-24N BETWEEN 34W-38W AND ENHANCING THE
ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE. THE REMAINDER OF THE
ATLC BASIN N OF THE TROPICS IS DOMINATED BY A SURFACE RIDGE
ANCHORED BY A 1027 MB HIGH JUST N OF THE DISCUSSION AREA NEAR
35N37W. AN UPPER RIDGE IN THE W TROPICAL ATLC EXTENDS FROM
13N59W N ALONG 23N57W TO 30N56W PROVIDING DIFFLUENCE ALOFT TO
GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 18N-26N
BETWEEN 54W-67W AND WITHIN 120/150 NM OF LINE FROM 12N52W TO
18N57W. T.S. RAFAEL IS EXPECTED TO MOVE ACROSS THE VIRGIN
ISLANDS THIS EVENING AND TONIGHT WHILE SLOWLY INTENSIFYING...
REACHING NEAR 19.2N 65.2W EARLY SUN...THEN CONTINUE NNW AND
GRADUALLY INTENSIFY TO 60 KT...REACHING 22.6N 67.0W EARLY
MON...THEN MOVE NORTHWARD AND EXIT THE REGION MON AND TUE.
REMNANTS OF PATTY WILL DISSIPATE THIS EVENING.

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

$$
PAW





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