[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 230557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...

AS OF 0300 UTC...AN INITIAL COLD FRONT EXTENDS FROM NEAR PANAMA CITY
BEACH FLORIDA TO 23N95W TO THE MEXICAN COAST NEAR 19N95W. A
SECONDARY AND STRONGER FRONT EXTENDS FROM JUST E OF LAFAYETTE
LOUISIANA TO ABOUT 60 NM S OF BROWNSVILLE TEXAS. THIS SECONDARY
FRONT HAS USHERED IN WINDS OF GALE FORCE...WITH WINDS OF 35 KT
LIKELY OCCURRING OVER THE FAR WESTERN GULF. A 0302 UTC ASCAT-B
PASS HAS INDICATED WINDS OF 30 KT OR GREATER WITHIN 90 NM NW OF
THE SECONDARY 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 INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE AFRICAN
COAST NEAR 5N9W TO 4N30W TO 2N40W TO THE COAST OF SOUTH AMERICA
NEAR 0N47W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM OF
THE AXIS BETWEEN 23W-31W...AND IN AN AREA FROM THE EQUATOR TO 6N
BETWEEN 38W-46W.

...DISCUSSION...

GULF OF MEXICO...

AS OF 0300 UTC...AN INITIAL COLD FRONT EXTENDS FROM NEAR PANAMA
CITY BEACH FLORIDA TO 23N95W TO THE MEXICAN COAST NEAR 19N95W. A
SECONDARY AND STRONGER FRONT EXTENDS FROM JUST E OF LAFAYETTE
LOUISIANA TO ABOUT 60 NM S OF BROWNSVILLE TEXAS. THIS SECONDARY
FRONT HAS USHERED IN WINDS APPROACHING GALE FORCE WITH MOST
BUOYS REPORTING WINDS OF 25 TO 30 KT AND SEAS BUILDING TO 11 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 PANAMA CITY
FLORIDA AND THE SOUTH-CENTRAL COAST OF LOUISIANA. 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.

CARIBBEAN SEA...

A 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 22N60W WAS EXPANDING ITS INFLUENCE OVER THE
CARIBBEAN E OF 73W WHILE A NARROW RIDGE PREVAILED OVER THE BASIN
BETWEEN 73W 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 FROM 18N56W TO 11N55W
MOVING W. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE TROUGH
AXIS. OF NOTE IN THE UPPER LEVELS...A LARGE UPPER LEVEL LOW IS
CENTERED NE OF THE LESSER ANTILLES NEAR 22N60W ENHANCING
SHOWERS. 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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