[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 102349
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT SEP 10 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

TROPICAL STORM NATE IS CENTERED NEAR 20.1N 94.7W AT 11/0000 UTC
OR 100 NM TO THE ENE OF VERACRUZ MEXICO AND 160 NM ESE OF TUXPAN
MEXICO MOVING W AT 5 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS
999 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65
KT. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM
18N-21N BETWEEN 91W-95W. SCATTERED MODERATE CONVECTION IS FROM
19N-23N BETWEEN 96W-97W...AND FROM 23N-27N BETWEEN 89W-95W.
FURTHER INTENSIFICATION IS EXPECTED AS NATE HEADS TOWARDS THE
MEXICAN COAST. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER
AWIPS/WMO HEADERS MIATCPAT5/WTNT35 KNHC AND THE FULL
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC
FOR MORE DETAILS.

TROPICAL STORM MARIA IS CENTERED NEAR 17.9N 62.4W AT 10/2100 UTC
OR 45 NM ESE OF ST. MARTIN AND 210 NM E OF SAN JUAN PUERTO RICO
MOVING NW AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007
MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT.
TWO LARGE CLUSTERS OF STRONG CONVECTION ARE FROM 14N-16N BETWEEN
59W-61WE...AND FROM 17N-20N BETWEEN 59W-62W. NUMEROUS MODERATE
CONVECTION IS ELSEWHERE FROM 10N-20N BETWEEN 57W-61W...AND FROM
13N-15N BETWEEN 61W-65W. HEAVY RAINFALL IS EXPECTED OVER THE
LESSER ANTILLES...THE VIRGIN ISLANDS...AND PUERTO RICO WITH
TOTAL RAINFALL AMOUNTS OF 2-4 INCHES. WITH HEAVY RAINFALL THERE
IS ALWAYS THE THREAT OF FLOODING AND MUDSLIDES ESPECIALLY IN
AREAS OF HIGH TERRAIN. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC EXTENDS FROM 17N40W
TO 9N46W MOVING W 15-20 KT. SATELLITE IMAGERY SHOWS WELL-DEFINED
CYCLONIC SURFACE FLOW AROUND THE ELONGATED WAVE AXIS. THE WAVE
ALSO COINCIDES WITH A LARGE SURGE OF DEEP LAYERED MOISTURE
EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 12N-18N BETWEEN 39W-46W...AND
FROM 10N-13N BETWEEN 46W-50W.

TROPICAL WAVE IS ENTERING THE WRN CARIBBEAN ALONG 20N79W TO
12N81W MOVING WNW NEAR 12 KT. THE SRN EXTENT OF THE WAVE AXIS
MEETS THE MONSOON TROUGH IN THE SW CARIBBEAN. SATELLITE IMAGERY
SHOWS BROAD CYCLONIC FLOW AROUND THE MONSOON TROUGH. THE WAVE
ALSO LIES ON THE WRN SIDE OF AN AREA OF ENHANCED MOISTURE.
ISOLATED MODERATE CONVECTION IS E OF THE AXIS FROM 13N-17N
BETWEEN 72W-79W. STRONGER CLUSTERS OF CONVECTION ARE N OF WAVE
ACROSS CUBA AND BETWEEN THE WAVE AXIS AND JAMAICA.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM A 1007 MB LOW NEAR THE AFRICAN
COAST AT 20N17W CONTINUING ALONG 11N21W 8N31W. THE ITCZ
CONTINUES FROM 8N31W ALONG 14N41W 10N48W 10N56W.

...DISCUSSION...

GULF OF MEXICO...
T.S. NATE CONTINUES TO IMPACT THE SW GULF OF MEXICO TONIGHT. SEE
SPECIAL FEATURES ABOVE FOR MORE DETAILS. A DYING STATIONARY
FRONT IS IN THE NE GULF OF MEXICO ACROSS NRN FLORIDA FROM CAPE
CANAVERAL TO TAMPA CONTINUING TO 27N84W. RADAR IMAGERY INDICATES
ISOLATED SHOWERS WITHIN 30 NM EITHER SIDE OF THE AXIS WITH
STRONGER CLUSTERS ACROSS THE SRN HALF OF THE FLORIDA PENINSULA
THAT MAY BE MORE ASSOCIATED WITH AFTERNOON HEATING THAN THE
FRONT. BESIDES THE CONVECTION OVER FLORIDA AND THAT ASSOCIATED
WITH NATE...THE REMAINDER OF THE BASIN IS UNDER MOSTLY CLEAR
SKIES INFLUENCED BY DRY AIR ALOFT AROUND AN UPPER LEVEL TROUGH
CENTERED OVER MISSOURI. UPPER LEVEL RIDGING COVERS THE REMAINDER
OF THE BASIN EXTENDING FROM THE OUTFLOW OF NATE TO THE WRN ATLC
N OF THE BAHAMAS. EXPECT THE FRONT TO CONTINUE TO DISSIPATE
WHILE NATE CONTINUES TO IMPACT THE SW GULF. A TROPICAL WAVE
CURRENTLY IN THE WRN CARIBBEAN WILL APPROACH THE SE GULF DURING
THE NEXT COUPLE OF DAYS WHICH WILL BRING HIGH MOISTURE VALUES TO
THAT AREA.

CARIBBEAN SEA...
A TROPICAL WAVE IS ACROSS THE WRN CARIBBEAN EXTENDING FROM S OF
CENTRAL CUBA TO NEAR 12N81W WHERE IT MEETS THE MONSOON TROUGH
THAT EXTENDS FROM THE NICARAGUA/COSTA RICA BORDER TO NRN
COLOMBIA. SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS MUCH OF
CUBA AND AROUND THE NRN EXTENT OF THE WAVE. A FEW ISOLATED
SHOWERS/THUNDERSTORMS ARE JUST E OF THE YUCATAN PENINSULA AND
ALSO E OF THE WAVE AXIS. SCATTERED SHOWERS/THUNDERSTORMS ARE
ALSO OVER NRN COLOMBIA ASSOCIATED WITH THE MONSOON TROUGH. BROAD
UPPER RIDING COVERS MOST THE BASIN CENTERED OVER THE MONA
PASSAGE WITH A WEAK INVERTED UPPER TROUGH OVER THE FAR WRN
PORTION OF THE BASIN HELPING SUPPORTING SOME OF THE CONVECTION
NEAR THE NRN EXTENT OF THE WAVE. T.S. MARIA IS IMPACTING THE FAR
ERN CARIBBEAN INCLUDING MUCH OF THE LESSER ANTILLES. WHILE THE
STORM CENTER IS NEAR THE NRN LEEWARD ISLANDS...CONVECTION
STRETCHES FROM N OF S AMERICA TO 20N WITH HEAVY ACTIVITY ALREADY
IMPACTING SOME OF THE WINDWARD ISLANDS. AS MARIA MOVES
NW...HEAVY RAINFALL WILL CONTINUE TO IMPACT THE ISLANDS
INCLUDING THE LESSER ANTILLES...THE VIRGIN ISLANDS...AND PUERTO
RICO. WITH HEAVY RAINFALL COMES THE THREAT OF POSSIBLE FLOODING
AND MUDSLIDES.

ATLANTIC OCEAN...
A WEAK 1015 MB SURFACE LOW AND ASSOCIATED DYING STATIONARY FRONT
ARE IMPACTING THE FAR WRN ATLC OFF THE E COAST OF NRN FLORIDA.
CLUSTERS OF STRONG SHOWERS/THUNDERSTORMS ARE ACROSS THE SRN HALF
OF THE FLORIDA PENINSULA WITH SOME ISOLATED ACTIVITY OFFSHORE
AND ACROSS THE NW BAHAMAS. A WEAK SURFACE TROUGH IS ALSO ACROSS
THE CENTRAL BAHAMAS FROM 26N73W TO 23N76W. SCATTERED
SHOWERS/THUNDERSTORMS ARE FROM 22N-24N BETWEEN 74W-76W.
ALOFT...A WEAK UPPER LEVEL RIDGE COVERS THE FAR W ATLC...WHILE
AN UPPER LEVEL TROUGH IS TO THE E ALONG 64W. THIS UPPER TROUGH
IS SHEARING T.S. MARIA NEAR THE NRN LEEWARD ISLANDS. STRONG
CONVECTION IS S OF 21N ASSOCIATED WITH THE STORM. SEE SPECIAL
FEATURES FOR MORE DETAILS. TO THE N AND E OF MARIA...A PAIR OF
1020 MB HIGHS IS DOMINATING THE ERN ATLC CENTERED NEAR 29N54W
AND 28N33W PROVIDING MOSTLY FAIR WEATHER. A WEAK SURFACE TROUGH
DIVIDES THE TWO HIGHS ALONG 32N43W TO 29N48W. ALOFT...AN UPPER
LEVEL RIDGE IS JUST E OF MARIA CENTERED NEAR 17N55W. AN UPPER
LEVEL LOW IS CENTERED NEAR 27N38W. WEAK UPPER RIDGING COVERS THE
FAR ERN ATLC.

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

$$
WALTON





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