[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231135
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST MON DEC 23 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...

AS OF 0900 UTC...AN INITIAL COLD FRONT EXTENDS FROM NEAR
APALACHICOLA FLORIDA TO 23N93W TO THE MEXICAN COAST NEAR 18N93W.
A SECONDARY AND STRONGER FRONT EXTENDS FROM BILOXI MISSISSIPPI
TO 25N94W. THIS SECOND FRONT HAS USHERED IN WINDS OF GALE
FORCE...30 TO 35 KT OVER THE SOUTHWESTERN GULF S OF 24N W OF
95W. AN EARLIER 0302 UTC ASCAT-B PASS HAS INDICATED WINDS OF 30
KT OR GREATER WITHIN 90 NM NW OF THE SECOND FRONT AND S OF
26N. GALE FORCE NORTHERLY WINDS OF 30-40 KT ARE EXPECTED TO
PERSIST UNTIL LATE TUE MAINLY S OF 22N W OF 95W. PLEASE REFER TO
THE LATEST NHC/TAFB HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS
MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH TRANSITIONS TO THE INTERTROPICAL CONVERGENCE
ZONE NEAR THE COAST OF AFRICA NEAR 6N13W. THE ITCZ CONTINUES
THROUGH 4N30W TO 2N40W TO THE COAST OF SOUTH AMERICA NEAR 0N48W.
SCATTERED MODERATE CONVECTION IS WITHIN 60-120 NM N OF THE AXIS
BETWEEN 25W-38W...AND IN AN AREA FROM THE EQUATOR TO 6N
BETWEEN 38W-47W.

...DISCUSSION...

GULF OF MEXICO...

AS OF 0900 UTC...AN INITIAL COLD FRONT EXTENDS FROM NEAR
APALACHICOLA FLORIDA TO 23N93W TO THE MEXICAN COAST NEAR 18N93W.
A SECONDARY AND STRONGER FRONT EXTENDS FROM BILOXI MISSISSIPPI
TO 25N94W. THIS SECONDARY FRONT HAS USHERED IN GALE FORCE WINDS
OVER THE SW GULF. BUOYS IN THE NW GULF REPORTED NORTHERLY WINDS
OF 25 TO 30 KT WITH SEAS GENERALLY 7 TO 10 FT. SOUTHERLY WINDS
OF 15 TO 20 KT ARE OCCURRING OVER THE GULF N OF 27N E OF THE
FRONT. COASTAL WSR-88D RADAR DATA SHOWS SCATTERED SHOWERS AND
THUNDERSTORMS BETWEEN THE TWO FRONTAL BOUNDARIES WITH THE BULK
OF THE ACTIVITY OCCURRING BETWEEN APALACHICOLA AND PENSACOLA
FLORIDA...WITH WEAKER ACTIVITY OVER THE EXTREME SE COAST OF
LOUISIANA AND MISSISSIPPI. FAIR SKIES PREVAIL ELSEWHERE OVER THE
GULF SE OF THE FIRST FRONT. IN THE UPPER LEVELS...BROAD SW FLOW
COVERS THE ENTIRE GULF BETWEEN AN ELONGATED ANTICYCLONE OVER THE
SW N ATLC AND A SHARP TROUGH OVER THE GREAT PLAINS. THE SW FLOW
ALOFT WAS ADVECTING DEEP TROPICAL MOISTURE WITHIN A NARROW 300
NM WIDE BAND TOWARD THE N-CENTRAL GULF COAST. THE COLD FRONTS
ARE FORECAST TO MERGE AND SWEEP RAPIDLY SE AND EXTEND FROM TAMPA
BAY FLORIDA TO THE YUCATAN PENINSULA BY LATE TONIGHT.

CARIBBEAN SEA...

AN EARLIER 0258 UTC ASCAT-B PASS INDICATED A BROAD SWATH OF 25-
30 KT TRADE WINDS OVER THE CARIBBEAN FROM 10N-16N BETWEEN 72W-
78W WITH THE HIGHEST WINDS...30 KT...WITHIN 90 NM OF THE COAST
OF COLOMBIA. 15-20 KT TRADEWINDS WERE NOTED OVER THE REMAINDER
OF THE CARIBBEAN SEA. SCATTERED LOW TOPPED SHOWERS ARE OVER
HONDURAS...NICARAGUA...AND COSTA RICA. MORE SCATTERED
SHOWERS ARE OVER HISPANIOLA... PUERTO RICO...AND THE LEEWARD
ISLANDS. IN THE UPPER LEVELS...A LARGE UPPER LOW OVER THE
TROPICAL ATLC NEAR 21N62W WAS EXPANDING ITS INFLUENCE OVER THE
CARIBBEAN E OF 75W WHILE A NARROW RIDGE PREVAILED OVER THE BASIN
BETWEEN 75W AND 85W. STRONG SUBSIDENCE DOMINATED THE CARIBBEAN
WHILE UPPER LEVEL MOISTURE WAS ON THE INCREASE OVER THE FAR NE
CARIBBEAN AND LEEWARD ISLANDS. THE UPPER LEVEL LOW IS FORECAST
TO MOVE W IN TANDEM WITH A SURFACE TROUGH OVER PUERTO RICO IN
THE NEXT 24 HOURS WITH AN INCREASE IN SHOWER AND THUNDERSTORM
ACTIVITY OVER THE E CARIBBEAN AND THE NORTHERN LEEWARD ISLANDS.

...HISPANIOLA...

SCATTERED WARM TOP SHOWERS ARE SWEEPING OVER THE HIGHER
ELEVATIONS OF HISPANIOLA. IN THE UPPER LEVELS...VERY STRONG
SUBSIDENCE IS SUPPRESSING THUNDERSTORM ACTIVITY. ONCE AGAIN THIS
WAS REFLECTED IN VERY DRY AIR ABOVE 600 MB IN THE 00Z SAN JUAN
RAOB. LITTLE CHANGE IN OVERALL CONDITIONS EXPECTED
TODAY...HOWEVER THE PROXIMITY OF A LARGE UPPER LOW AND A
SURFACE TROUGH OVER PUERTO RICO MAY RESULT IN SOME ADDITIONAL
ACTIVITY MON NIGHT AND TUE.

ATLANTIC OCEAN...

A STATIONARY 1034 MB HIGH IS CENTERED OVER THE W ATLANTIC NEAR
35N51W PRODUCING FAIR WEATHER OVER THE BAHAMAS AND W ATLANTIC.
ASSOCIATED RIDGE EXTENDS EASTWARD OVER THE SUBTROPICAL ATLC
ALONG 31N TO THE NW COAST OF AFRICA. IN THE TROPICS...A
SURFACE TROUGH IS E OF THE LESSER ANTILLES AND WAS RELOCATED
SLIGHTLY E AND CURRENTLY EXTENDS FROM 19N54W TO 09N55W MOVING W.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE OCCURRING
OVER THE NORTHERN PORTION OF THE TROUGH AND ENHANCED BY AN UPPER
LOW NEAR 21N62W. ACTIVITY WAS GENERALLY FROM 17N TO 21N BETWEEN
53W AND 62W. ELSEWHERE...UPPER LEVEL DIFFLUENCE OVER THE CANARY
ISLANDS ARE ENHANCING SHOWERS.

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

$$
COBB


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