000
AXNT20 KNHC 210557
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 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 34N60W AND A 1003 MB LOW CENTERED OVER NORTH COLOMBIA NEAR
6N75W. A 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 STILL OCCURRING. 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 8N13W TO 6N25W TO 4N40W TO THE COAST OF SOUTH AMERICA
NEAR 1N50W. SCATTERED MODERATE CONVECTION IS FROM 5N-7N BETWEEN
18W-23W.
...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 STRONG
COLD FRONT IS FORECAST TO MOVE OFF THE TEXAS COAST LATE SAT
AFTERNOON WITH INCREASING NORTHERLY WINDS BEHIND THE FRONT.
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. A 0248 UTC ASCAT PASS AND SURFACE
OBSERVATIONS INDICATED 15-20 KT TRADEWINDS ARE 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 INDICATED
SCATTERED SHOWERS SWEEPING ACROSS THE ISLAND WITH CONCENTRATED
ACTIVITY ALONG THE N 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 34N60W PRODUCING
FAIR WEATHER OVER THE BAHAMAS AND WESTERN ATLANTIC. THE TAIL END
OF A STATIONARY FRONT ENTERS THE DISCUSSION AREA NEAR 32N45W.
ANOTHER 1034 MB HIGH IS CENTERED OVER THE FAE 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 EARLIER THIS
EVENING. A SURFACE TROUGH CENTERED OVER THE CENTRAL TROPICAL
ATLANTIC EXTENDS FROM 18N42W TO 7N40W. SCATTERED LOW TOPPED
SHOWERS ARE WITHIN 180 NM W OF THE TROUGH AXIS. 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 20N-32N BETWEEN 23W-32W.
FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE
$$
COBB
