[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221123
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN DEC 22 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...FROM 11N-13N
BETWEEN 74W-78W. THE WINDS SHOULD DECREASE BELOW GALE FORCE
WITHIN THE NEXT 6 TO 12 HOURS. THE WINDS ARE DUE TO A STRONG
PRESSURE GRADIENT BETWEEN A 1034 MB HIGH CENTERED OVER THE NORTH
CENTRAL ATLANTIC NEAR 35N51W AND BROAD LOW PRES CENTERED OVER
NORTHERN COLOMBIA.

A COLD FRONT EXTENDING FROM JUST E OF LAFAYETTE LOUISIANA TO
JUST N OF TAMPICO MEXICO WILL SWEEP SE AND BE REINFORCED BY A
SECONDARY SURGE OF COLD AIR. THIS SECONDARY SURGE OF COLD AIR
WILL RESULT IN GALE FORCE WINDS OF 30 TO 40 KT BY MON MORNING
OVER THE SW GULF S OF 20N W OF 95W.

FOR BOTH GALE AREAS...PLEASE REFER TO THE LATEST NHC/TAFB 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 6N10W TO 6N20W TO 3N40W TO THE COAST OF SOUTH AMERICA
NEAR 50W. SCATTERED MODERATE CONVECTION WAS INDICATED WITHIN 60
NM EITHER SIDE OF THE ITCZ BETWEEN 27W-38W.

...DISCUSSION...

GULF OF MEXICO...

AS OF 0900 UTC...A COLD FRONT EXTENDED FROM JUST E OF LAFAYETTE
LOUISIANA TO JUST N OF TAMPICO MEXICO. S TO SE WINDS OF 20 TO 25
KT WERE OCCURRING OVER THE GULF N OF 27N E OF THE FRONT TO THE
FLORIDA BIG BEND. COASTAL WSR-88D RADAR IMAGERY INDICATED STRONG
THUNDERSTORMS ALONG AND WITHIN 60 NM E OF THE FRONT OVER SE
LOUISIANA AND MISSISSIPPI. WIDELY SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WERE NOTED WITHIN 180 NM NW OF THE FRONTAL
BOUNDARY ALONG THE REMAINDER OF THE LOUISIANA AND UPPER TEXAS
COASTS. WINDS ELSEWHERE E OF THE FRONT WERE GENERALLY FROM SE TO
S AT 10 TO 15 KT. THERE WERE REPORTS OF LOW CEILINGS AND FOG
OUTSIDE OF CONVECTIVE ACTIVITY OVER THE NORTHERN GULF AHEAD OF
THE FRONT. IN THE UPPER LEVELS...SW FLOW ON THE BACKSIDE OF AN
UPPER LEVEL ANTICYCLONE NEAR 26N75W AND ASSOCIATED RIDGE WAS
ADVECTING MID TO UPPER LEVEL MOISTURE OVER THE E GULF AND WITHIN
A NARROW BAND OVER LOUISIANA/MISSISSIPPI. SOME SUBSIDENCE WAS
OVER THE REMAINDER OF THE GULF. THE COLD FRONT IS FORECAST TO
SWEEP EASTWARD AND EXTEND FROM THE FLORIDA PANHANDLE TO THE BAY
OF CAMPECHE BY SUN NIGHT.

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. AN EARLIER 0226 UTC ASCAT PASS INDICATED
A LARGE AREA OF 20-25 KT TRADEWINDS OVER THE CARIBBEAN SEA FROM
11N TO 18N BETWEEN 65W AND 80W...WITH THE STRONGEST WINDS
OCCURRING JUST S OF HISPANIOLA AND NEAR THE WINDWARD PASSAGE.
SCATTERED WARM TOP SHOWERS ARE OVER THE GULF OF
HONDURAS...BELIZE... GUATEMALA...HONDURAS...NICARAGUA...AND
COSTA RICA. ADDITIONAL ACTIVITY WAS FOCUSED OVER E
CUBA...JAMAICA...HISPANIOLA... PUERTO RICO...THE LEEWARD
ISLANDS...AND THE WINDWARD ISLANDS.  THE UPPER LEVELS...A CLOSED
ANTICYCLONE NEAR 26N75W WAS PROVIDING A LOW-LATITUDE REX
BLOCKING PATTERN OVER THE CARIBBEAN AND WRN ATLANTIC WITH AN
ATTENDANT TROUGH AXIS EXTENDING FROM THE TROPICAL ATLC WESTWARD
ACROSS THE NORTHERN LEEWARD ISLANDS...AND JUST S OF PUERTO
RICO...HISPANIOLA TO E CUBA. VERY STRONG SUBSIDENCE WAS NOTED
WITHIN 180-240 NM OF THE TROUGH AXIS. THE BLOCKING PATTERN OVER
THE CARIBBEAN IS EXPECTED TO PERSIST OVER THE NEXT 24
HOURS...AND PERHAPS AMPLIFY BEYOND AS AN UPPER LOW IS EXPECTED
TO CLOSE OFF OVER PUERTO RICO BY LATE MON.

...HISPANIOLA...

SCATTERED LOW TOPPED SHOWERS ARE OVER HISPANIOLA MOVING W WITHIN
FRESH TRADEWIND FLOW. CONDITIONS REMAIN CAPPED DESPITE THE
PRESENCE OF AN UPPER LEVEL TROUGH LYING JUST S OF THE AREA. THE
VERY STRONG SUBSIDENCE ALOFT WAS  CAPTURED BY VERY DRY AIR ABOVE
650 MB IN THE 00Z SAN JUAN RAOB. LITTLE CHANGE IN THIS SCENARIO
IS EXPECTED OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...

A 1034 MB HIGH IS CENTERED NE OF BERMUDA NEAR 35N51W IS
PRODUCING FAIR WEATHER OVER THE BAHAMAS AND W ATLANTIC. ANOTHER
1032 MB HIGH IS CENTERED OVER THE E ATLANTIC NEAR 35N16W. A
SURFACE TROUGH IS OVER THE CENTRAL ATLANTIC FROM 30N39W TO
22N41W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE
WITHIN 60 NM W AND 120 NM E OF THE TROUGH. ANOTHER SURFACE
TROUGH IS OVER THE TROPICAL ATLANTIC FROM 20N53W TO 11N49W
MOVING W. SCATTERED SHOWERS ARE WITHIN 180 NM OF THE TROUGH
AXIS...WITH AN ADDITIONAL PATCH OF SHOWERS AND THUNDERSTORMS
NOTED FROM 19N-23N BETWEEN 54W-59W. OF NOTE IN THE UPPER
LEVELS...A SHEARING UPPER LEVEL LOW IS CENTERED OVER THE E
ATLANTIC NEAR 31N25W. A SHARPENING UPPER LEVEL TROUGH EXTENDING
FROM 31N48W SW TO 22N56W WILL CLOSE OFF INTO AN UPPER LOW OVER
THE NEXT 24 TO 48 HOURS AS IT MOVES TOWARD PUERTO RICO.

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

$$
COBB


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