[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201052
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU MAR 20 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0345 UTC.

...THE ITCZ...

FROM THE LIBERIA COAST NEAR 6N10W TO 4N20W 1N30W...IN BETWEEN
THE EQUATOR AND 1N BETWEEN 30W AND 38W...CROSSING THE EQUATOR
AT 39W...AND GOING INTO NORTHEASTERN BRAZIL NEAR 4S47W.
ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS
SOUTH OF 6N BETWEEN AFRICA AND 46W.

...DISCUSSION...

THE GULF OF MEXICO...

UPPER LEVEL SOUTHWESTERLY WIND FLOW COVERS THE AREA...AS
A COLD FRONT MOVES EASTWARD THROUGH THE AREA. THE DEEP LAYER
TROUGH THAT IS SUPPORTING THIS FRONT HAS MOVED NORTH OF 30N
AND INTO THE NORTHEASTERN U.S.A. THE CURRENT MIDDLE TO UPPER
LEVEL SOUTHWESTERLY WIND FLOW IN THE AREA IS A RESULT OF THE
DISPLACEMENT OF THE TROUGH TO THE NORTHEAST OF THE AREA. THE
COLD FRONT PASSES THROUGH NORTHEASTERN FLORIDA TO 25N86W...TO
THE NORTH CENTRAL YUCATAN PENINSULA COAST... INTO MEXICO EAST
OF THE ISTHMUS OF TEHUANTEPEC. A STATIONARY FRONT STARTS IN
MEXICO JUST WEST OF THE ISTHMUS OF TEHUANTEPEC AND CONTINUES TO
21N99W. NEAR GALE-FORCE WINDS ARE BLOWING FROM THE SOUTHWESTERN
CORNER OF THE GULF OF MEXICO ACROSS THE INTERIOR OF MEXICO ALONG
94W INTO THE GULF OF TEHUANTEPEC...BECOMING GALE-FORCE ON THE
EASTERN PACIFIC OCEAN SIDE OF MEXICO. THE STRONG SHOWERS AND
THUNDERSTORMS FROM SIX HOURS AGO IN THE YUCATAN PENINSULA AND
GUATEMALA HAVE WEAKENED WITH REMNANT CLOUDS. SHOWERS ARE POSSIBLE
WITHIN 90 NM ON EITHER SIDE OF THE LINE THROUGH 31N79W TO 28N82W
IN WEST CENTRAL FLORIDA...TO 25N85W IN THE GULF OF MEXICO TO THE
NORTHEASTERN CORNER OF THE YUCATAN PENINSULA.

THE ATLANTIC OCEAN WEST OF 54W...

UPPER LEVEL ANTICYCLONIC WIND FLOW WEST OF 54W IS COURTESY OF
AN ATLANTIC OCEAN RIDGE FROM EASTERN CUBA BEYOND 32N69W.

THE CARIBBEAN SEA...

THE TAIL END OF A WEAKENING COLD FRONT CUTS ACROSS THE EASTERN
CARIBBEAN SEA ISLANDS THROUGH 14N60W TO 14N62W. COOLER AND DRIER
AIR FROM THE SURFACE UPWARD INTO THE ATMOSPHERE HAS SPREAD WELL
SOUTHWARD INTO THE EASTERN CARIBBEAN SEA BEHIND THIS MOST RECENT
COLD FRONT. TEMPERATURES THIS MORNING AT 20/0600 UTC RANGED FROM
18 DEGREES CENTIGRADE TO 25 DEGREES CENTIGRADE BEHIND THE
FRONT. DEWPOINTS RANGED FROM THE MIDDLE TEENS CENTIGRADE TO THE
LOW 20'S CENTIGRADE. ANOTHER BIG STORY IS THE TREMENDOUS
NORTHERLY SWELLS AFFECTING THE CARIBBEAN SEA ISLANDS FROM THE
CONTINUOUS FETCH DRIVEN BY A LARGE LINGERING AND ONCE VERY
POWERFUL NORTHERN ATLANTIC OCEAN LOW PRESSURE CENTER. SHOWERS
ARE POSSIBLE EAST OF 70W IN CLUSTERS OF LOW CLOUDS MOVING INTO
THE AREA FROM THE ATLANTIC OCEAN. THE REST OF THE CARIBBEAN SEA
IS EXPERIENCING A STRONGLY SUBSIDENT MIDDLE TO UPPER LEVEL
ENVIRONMENT. THE TIGHT SURFACE PRESSURE GRADIENT BETWEEN
SEMI-PERMANENT LOW PRESSURE IN NORTHERN SECTIONS OF SOUTH
AMERICA AND A 1024 MB ATLANTIC OCEAN HIGH NEAR 29N67W IS HELPING
TO PRODUCE GALE FORCE TRADEWINDS NEAR THE COAST OF COLOMBIA.
THESE CONDITIONS ARE EXPECTED TO SUBSIDE IN ABOUT 24 HOURS.

THE REST OF THE ATLANTIC OCEAN EAST OF 54W...
BROAD DEEP LAYER CYCLONIC WIND FLOW ACCOMPANIES THE CENTRAL
ATLANTIC OCEAN TROUGH. THIS TROUGH SUPPORTS THE COLD FRONT THAT
PASSES THROUGH 31N40W TO 29N40W 20N46W 15N54W...DISSIPATING FROM
15N54W TO 14N60W AND 14N62W IN THE EASTERN CARIBBEAN SEA.
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE
NORTH OF 27N BETWEEN 35W AND 40W. OTHER SHOWERS ARE POSSIBLE
WITHIN 180 NM ON EITHER SIDE OF 16N61W 19N50W 27N40W. BROAD
UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE AREA SOUTH AND
SOUTHEAST OF THE CENTRAL ATLANTIC TROUGH.

$$
MT




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