[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 031743
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT DEC 03 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.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH REMAINS INLAND ACROSS AFRICA. THE STARTS TO
DEVELOP INLAND OVER LIBERIA AND ENTERS THE ERN TROPICAL ATLC
ACROSS SIERRA LEONE NEAR 8N13W CONTINUING WSW ALONG 6N20W 4N30W
TO 3N37W. CLUSTERS OF SCATTERED WEAK CONVECTION ARE WITHIN
100-150 NM ON EITHER SIDE OF THE ITCZ BETWEEN 18W-34W.

...DISCUSSION...

GULF OF MEXICO...
CLUSTERS OF LOW TOP SCATTERED SHOWERS ARE OBSERVED ACROSS THE
DISCUSSION AREA ON INFRA-RED IMAGERY THIS LATE MORNING. THESE
GROUP OF SHOWERS ARE MOVING WITH THE ANTICYCLONIC FLOW AROUND A
SURFACE RIDGE COVERING THE ERN AND SE CONUS. THE SURFACE
PRESSURE GRADIENT HAS BECOME TIGHTER OVER THE PAST 12 HOURS OVER
THE NW BASIN...ALLOWING FOR AN INCREASING RETURN FLOW UP TO 25
KT N OF 25N W OF 87W. LOOKING AT WATER VAPOR IMAGERY...AN UPPER
RIDGE MOVES ACROSS THE GULF WITH DRY STABLE AIR ALOFT AND STRONG
SUBSIDENCE OVER THE AREA. RIGHT BEHIND THIS FEATURE THERE IS AN
UPPER LEVEL LONGWAVE/TROUGH MOVING ACROSS NRN MEXICO WITH A 110+
KT JET-STREAK DEPICTED ON MODEL DATA AND UPPER LEVEL SATELLITE
DERIVED WINDS. THIS SYSTEM WILL BE OUR NEXT WEATHER PRODUCER
OVER THE NEXT SEVERAL DAYS...AS THE SURFACE RIDGE SHIFTS EAST
INTO THE WRN ATLC...IN ADVANCE OF THE NEXT COLD FRONT EXPECTED
TO MOVE INTO THE NW GULF ON MONDAY BRINGING GUSTY NORTHERLY
WINDS TO THIS REGION.

CARIBBEAN SEA...
CLUSTERS OF SCATTERED WEAK SCATTERED SHOWERS ARE MOVING
SOUTHWESTERLY W OF 74W. THESE GROUP OF SHOWERS ARE SUPPRESSED BY
A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE
WEST COAST OF GUATEMALA AND A SHARP UPPER TROUGH EXTENDING S
ACROSS THE WRN ATLC IN TO THE NORTH CENTRAL CARIBBEAN...BOTH
PROVIDING DRY STABLE AIR ALOFT AND STRONG SUBSIDENCE TO ALMOST
THE ENTIRE DISCUSSION AREA...EXCEPT THE FAR SE BASIN...WHERE A
NEARLY STATIONARY SURFACE TROUGH IMPACTS THE LESSER ANTILLES AND
ADJACENT WATERS WITH SCATTERED SHOWERS AND THUNDERSTORMS S OF
17N E OF 67W. THIS TROUGH EXTENDS ACROSS THE ATLC INTO THE
CARIBBEAN ALONG THE ISLAND OF DOMINICA TO THE COASTAL CITY OF
CUMANA IN VENEZUELA. RAINFALL TOTAL ESTIMATES OVER THE PAST FEW
DAYS HAVE RANGED FROM ONE INCH TO OVER 2 INCHES FOR THESE GROUP
OF ISLANDS. DUE TO THE ALREADY SATURATED TERRAIN FROM THE PAST
RAINFALL EVENTS AND SHORT RANGE COMPUTER MODELS SUGGESTING THE
CONVECTION LINGERING OVER THE NEXT FEW DAYS IN THIS REGION...THE
POSSIBILITY FOR INLAND FLOODING IS HIGHLY EXPECTED FOR THE NEXT
FEW DAYS...ESPECIALLY OVER THE HIGHER TERRAIN. FINALLY...THE
MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM NRN COLOMBIA
TO ACROSS COSTA RICA GENERATING ISOLATED SHOWERS WITHIN 70 NM
ALONG THE COAST WRN PANAMA AND COSTA RICA.

ATLANTIC OCEAN...
AN UPPER TROUGH IS MOVING ACROSS THE WRN SUPPORTING A SET OF 2
NEARLY STATIONARY TROUGHS. ONE IS ANALYZED FROM 30N61W TO 22N67W
WITH NO CONVECTION. THE SECOND ONE IS SOMEWHAT ASSOCIATED TO A
SURFACE LOW N OF THE AREA THAT EXTENDS A FRONTAL SYSTEM INTO OUR
AREA AS A SURFACE TROUGH EXTENDING SSW FROM 30N56W 23N60W INTO
THE CARIBBEAN BASIN ALONG THE ISLAND OF DOMINICA. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 70 NM ON EITHER
SIDE OF THE AXIS. TO THE E OF THIS SURFACE TROUGH...AN UPPER
LEVEL CYCLONIC CIRCULATION MOVES WESTWARD ACROSS THE CENTRAL
ATLC CENTERED NEAR 28N39W...REFLECTING A WEAK SURFACE TROUGH
ANALYZED FROM 30N38W TO 20N40W. DESPITE THE SURFACE CYCLONIC
TURNING ALONG THE TROUGH AXIS...THE CONVECTION IS MORE RELATED
TO THE MID-UPPER LEVEL LIFTING FROM THE UPPER LOW...GENERATING
WEAK ISOLATED SHOWERS FROM 26N-32N BETWEEN 32W-40W. THE
REMAINDER OF THE ATLC IS DOMINATED BY THE BROAD SURFACE RIDGE
CENTERED NE OF THE AZORES NEAR 38N23W. SURFACE RIDGING WILL
BUILD OVER THE WRN ATLC OVER THE NEXT FEW DAYS.

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

$$

GARCIA




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