[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150104
TWDAT

TROPICAL WEATHER DISCUSSION...CORRECTION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED JAN 14 2009

...CORRECTED WORD AND ATLC SECTION...

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...

ITCZ IS CENTERED ALONG 9N13W 3N20W 3N30W 2N40W...CROSSING THE
EQUATOR ALONG 45W...INTO NORTHEASTERN BRAZIL NEAR 1S48W. A
CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS FROM
3.5N-6N BETWEEN 13W-16W. ISOLATED MODERATE CONVECTION IS FROM
4N-6.5N BETWEEN 28W-37W.

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 2100 UTC...A 1026 MB HIGH IS CENTERED OVER SW LOUISIANA
NEAR 30N93W ENVELOPING THE SE CONUS AND THE ENTIRE GULF REGION.
UNDER THE INFLUENCE OF THIS SYSTEM...MOSTLY FAIR WEATHER AND
LIGHT TO MODERATE WINDS PREVAIL. ABUNDANT CLOUDINESS IS NOTED
OVER SE MEXICO INCLUDING MUCH OF THE BAY OF CAMPECHE AND THE
YUCATAN PENINSULA. IN THE UPPER LEVELS...A BROAD MID/UPPER LEVEL
TROUGH REMAINS OVER THE CENTRAL CONUS AND NORTHERN MEXICO.
SOUTHWESTERLY WINDS AHEAD OF THE TROUGH DOMINATE THE ENTIRE
GULF. THESE WINDS ARE ADVECTING CONSIDERABLE MID TO UPPER LEVEL
MOISTURE FROM THE EPAC ACROSS SOUTH-CENTRAL MEXICO AND THE
YUCATAN PENINSULA INTO THE GULF OF MEXICO AND SOUTH FLORIDA. MID
TO UPPER LEVEL SUBSIDENCE AND ASSOCIATED DRY AIR IS OVER THE
NORTHERN GULF WATERS. LOOKING AHEAD...THE HIGH PRES OVER SW
LOUISIANA IS FORECAST TO WEAKEN TONIGHT AS ANOTHER REINFORCING
COLD FRONT EXITS THE E AND SE U.S. AND MOVES INTO THE W ATLC.
STRONG HIGH PRES BEHIND THIS FRONT WILL BUILD ACROSS THE REGION
THU THROUGH EARLY SAT PRODUCING MODERATE TO STRONG NE WINDS
ACROSS THE ENTIRE GULF OF MEXICO.

THE CARIBBEAN SEA...
A COLD FRONT FROM THE ATLC ENTERS THE CARIBBEAN SEA THROUGH
CENTRAL CUBA THEN CONTINUES SW AS A STATIONARY FRONT TO NORTHERN
HONDURAS NEAR 16N87W. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE
FRONT. THE FRONT WILL REMAIN STATIONARY DURING THE NEXT 24 HOURS
GENERATING SOME SHOWER ACTIVITY OVER PART OF CUBA AND THE GULF
OF HONDURAS. MODERATE TO STRONG TRADE WINDS CONTINUES TO BLOW
ACROSS THE BASIN DUE TO A TIGHT SURFACE PRESSURE GRADIENT
BETWEEN A HIGH LOCATED NE OF AREA AND LOWER PRESSURE OVER
NORTHERN SOUTH AMERICA. PATCHES OF LOW-LEVEL MOISTURE ARE SEEN
OVER THE CENTRAL CARIBBEAN JUST SOUTH OF JAMAICA. LOW/MID CLOUDS
WITH EMBEDDED LIGHT SHOWERS COVER MUCH OF HONDURAS AND
NICARAGUA. ALOFT...AN UPPER LEVEL HIGH CENTERED OVER PUERTO RICO
EXTENDS A RIDGE OVER THE ENTIRE AREA. SW FLOW ON THE WESTERN
PERIPHERY OF THIS HIGH IS TRANSPORTING MID/UPPER LEVEL MOISTURE
ACROSS THE NW CARIBBEAN AND CUBA INTO THE BAHAMAS AND THE W
ATLC.

THE ATLANTIC OCEAN...
SINCE YESTERDAY...A VERY INTERESTING AND UNUSUAL WEATHER FEATURE
IS TAKING SHAPE E OF THE LESSER ANTILLES. BASED ON SATELLITE
IMAGERY...THE CLOUD PATTERN IS EXHIBITING A WELL DEFINED
CYCLONIC CIRCULATION. THIS SYSTEM IS GETTING THE ENERGY FROM
STRONG LOW LEVEL WINDS WHILE UPPER-LEVEL DIFFLUENCE AHEAD OF A
BROAD UPPER-LEVEL TROUGH OVER THE CENTRAL ATLC IS ENHANCING
THE ASSOCIATED CLOUDINESS. THE CENTER IS ESTIMATED BETWEEN NOAA
BUOYS 41040 AND 41041. BASED ON THE ABOVE...A SFC TROUGH WILL
LIKELY BE ADDED ON THE 00Z SFC ANALYSIS. THE GFS MODEL SUGGESTS
THAT THIS SYSTEM WILL MOVE WWD UNDER THE TRADE WIND FLOW
AFFECTING THE LESSER ANTILLES EARLY FRI AND THEN THE US/UK
VIRGIN ISLANDS AND PUERTO RICO FRI THROUGH SAT PRODUCING A
NOTICEABLE INCREASE IN MOISTURE. THIS MAY ALLOW FOR AN INCREASE
IN SHOWER ACTIVITY TO THOSE ISLANDS. ELSEWHERE...A COLD FRONT
ENTERS THE FORECAST AREA NEAR 31N68W THEN CONTINUES SW CROSSING
THE BAHAMAS AND CENTRAL CUBA INTO THE CARIBBEAN SEA WHERE IT
BECOMES STATIONARY. SCATTERED SHOWERS ARE ASSOCIATED WITH THE
FRONTAL BOUNDARY. JUST AHEAD OF THE FRONT...SW TO S WINDS OF 15
TO 20 KT PREVAIL WHILE NLY WINDS OF 15 TO 20 KT ARE SEEN BEHIND
THE FRONT. THE REMAINDER OF THE FORECAST REGION REMAINS UNDER
THE INFLUENCE OF A SFC RIDGE ANCHORED BY A 1032 MB HIGH SITUATED
W OF THE AZORES NEAR 37N38W. ALOFT...A RIDGE/TROUGH/RIDGE
PATTERN DOMINATES THE DISCUSSION AREA.

$$
GR




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