[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211206
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT DEC 21 2013

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...SPECIAL FEATURES...

GALE FORCE WINDS ARE OCCURRING ACROSS PORTIONS OF THE SW
CARIBBEAN SEA...NORTH OF THE COAST OF COLOMBIA...DUE TO STRONG
PRESSURE GRADIENT BETWEEN A 1032 MB HIGH CENTERED NE OF BERMUDA
NEAR 34N56W AND A 1007 MB LOW CENTERED OVER NORTH COLOMBIA NEAR
9N75W. AN EARLIER 0248 UTC ASCAT PASS SHOWED A SOLID AREA OF 25-
30 KT WINDS AND GIVEN THE LOW BIAS OF ASCAT...THERE ARE LIKELY
ISOLATED AREAS OF GALE FORCE WINDS OCCURRING. GALE FORCE WINDS
IN THE AREA ARE EXPECTED TO PERSIST UNTIL SUN MORNING. SEE LATEST
NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02
KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...

THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE AFRICAN
COAST NEAR 7N12W TO 3N25W TO 3N40W TO THE COAST OF SOUTH AMERICA
NEAR 1N50W. SCATTERED MODERATE CONVECTION IS WITHIN 30-45 NM OF
A LINE FROM 5N20W TO 5N25W.

...DISCUSSION...

GULF OF MEXICO...

A 1032 MB HIGH CENTERED NE OF BERMUDA AND AN ASSOCIATED RIDGE
AXIS EXTENDING WESTWARD ALONG 30N/31N IS PRODUCING 10-20 KT SE
RETURN FLOW OVER THE GULF OF MEXICO. THE FLOW OF WARM AND VERY
MOIST AIR OVER THE COOLER SHELF WATERS OF THE GULF OF MEXICO IS
RESULTING IN AREAS OF LOW CEILINGS AND FOG MAINLY N OF 25N AND W
OF 90W. ADDITIONAL PATCHES OF LOW CLOUDS WERE NOTED OVER THE NE
GULF NEAR THE FLORIDA BIG BEND. OTHERWISE MOSTLY CLEAR SKIES
PREVAIL. IN THE UPPER LEVELS...RIDGE AXIS EXTENDS FROM AN
ANTICYCLONE OVER COLOMBIA NORTHWARD ALONG 80W. SOUTHWESTERLY
FLOW ON THE BACKSIDE OF THE RIDGE AND WELL E OF A SHARP UPPER
LEVEL TROUGH OVER WESTERN NEW MEXICO IS ADVECTING MID TO UPPER
LEVEL MOISTURE OVER TEXAS AND THE NW GULF N OF 27N W OF 90W.
STRONG SUBSIDENCE IS OVER THE REMAINDER OF THE GULF. A COLD
FRONT IS FORECAST TO MOVE OFF THE TEXAS COAST LATER THIS
AFTERNOON WITH A WIND SHIFT...WITH A REINFORCING SURGE SLATED TO
MOVE OFF LATE SUN ACCOMPANIED BY INCREASING NORTHERLY WINDS.

CARIBBEAN SEA...

GALE FORCE WINDS ARE OCCURRING ACROSS PORTIONS OF THE SW
CARIBBEAN SEA...NORTH OF THE COAST OF COLOMBIA. SEE SPECIAL
FEATURES SECTION ABOVE. LATEST SURFACE OBSERVATIONS INDICATED 15-
20 KT TRADEWINDS OVER THE REMAINDER OF THE CARIBBEAN SEA E OF
80W...WITH LIGHTER WINDS NOTED W OF 80W. SCATTERED LOW TOPPED
SHOWERS ARE OVER THE GULF OF HONDURAS...BELIZE... HONDURAS...AND
NICARAGUA. MORE SCATTERED SHOWERS ARE OVER E CUBA...HISPANIOLA
PUERTO RICO...AND THE LEEWARD ISLANDS. WSR-88D IMAGERY FROM SAN
JUAN CONTINUED TO INDICATE SCATTERED SHOWERS SWEEPING ACROSS THE
ISLAND WITH CONCENTRATED ACTIVITY ALONG THE NE COAST OF PUERTO
RICO. IN THE UPPER LEVELS...A RIDGE EXTENDS SE TO NW FROM
COLOMBIA ACROSS THE WESTERN CARIBBEAN SEA TO THE GULF/FLORIDA
ALONG 80W. STRONG SUBSIDENCE COVERS VIRTUALLY THE ENTIRE
CARIBBEAN SEA...EXCEPT OVER THE FAR NW PORTION. THE FAIRLY
STABLE CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE WEEKEND.

...HISPANIOLA...

SCATTERED LOW TOPPED SHOWERS ARE OVER THE DOMINICAN REPUBLIC AND
HAITI IN MODERATE TO FRESH TRADEWIND FLOW. GENERALLY STABLE
CONDITIONS ARE EXPECTED THROUGH THE WEEKEND AS STRONG UPPER
LEVELS SUBSIDENCE PREVAILS. THE STRONG SUBSIDENCE IS REFLECTED
IN VERY DRY AIR ABOVE 700 MB IN THE 00Z SAN JUAN RAOB.

ATLANTIC OCEAN...

A 1032 MB HIGH IS CENTERED NE OF BERMUDA NEAR 34N56W PRODUCING
FAIR WEATHER OVER THE BAHAMAS AND WESTERN ATLANTIC. ANOTHER 1033
MB HIGH IS CENTERED OVER THE FAR NE ATLANTIC NEAR 37N16W.
ELSEWHERE...FRESH TO STRONG NORTHEASTERLY WINDS ARE OCCURRING IN
THE REGION TO WEST OF THE CAPE VERDE ISLANDS NEAR 16N28W.
SCATTEROMETER PASSES MISSED THE AREA FRI NIGHT. A SURFACE TROUGH
CENTERED OVER THE CENTRAL TROPICAL ATLANTIC EXTENDS FROM 19N44W
TO 7N43W. SCATTERED LOW TOPPED SHOWERS ARE WITHIN 120 NM EITHER
SIDE OF THE TROUGH AXIS. ANOTHER SURFACE TROUGH EXTENDED FROM
31N31W TO 21N35W. A LARGE MID TO UPPER LEVEL LOW IS CENTERED
OVER THE E ATLANTIC NEAR 26N33W. THIS LOW IS PRODUCING SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS FROM 23N-32N BETWEEN 25W-33W.

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

$$
COBB


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