[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED APR 21 2010

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...

FROM THE SOUTHERN COAST OF GUINEA TO 4N20W...CROSSING THE EQUATOR
ALONG 26W...1S30W...INTO NORTHEASTERN BRAZIL NEAR 4S40W...TO
4S50W. STRONG SHOWERS AND THUNDERSTORMS ARE IN COASTAL LIBERIA.
ISOLATED SHOWERS ARE TO THE SOUTH OF 8N TO THE EAST OF 50W.

...DISCUSSION...

THE GULF OF MEXICO...
AN UPPER LEVEL TROUGH ON TOP OF CALIFORNIA IS DEEPENING...WITH
THE BASE OF THE TROUGH REACHING THE EASTERN PACIFIC OCEAN JUST
TO THE WEST OF THE NORTHERN BAJA CALIFORNIA PENINSULA. THE
DEEPENING TROUGH IS HELPING TO BUILD THE UPPER LEVEL RIDGE AND
ITS ACCOMPANYING ANTICYCLONIC FLOW ACROSS MEXICO. A BROAD MIDDLE
LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM THE NORTHWESTERN
CARIBBEAN SEA JUST OFF THE NORTHEASTERN TIP OF THE YUCATAN
PENINSULA BEYOND NORTH CENTRAL FLORIDA AND COASTAL GEORGIA.
A SURFACE TROUGH EXTENDS FROM THE CENTRAL STRAITS OF FLORIDA
TO THE EAST CENTRAL FLORIDA COAST...STRADDLING THE COAST...AND
THEN BEYOND NORTHEASTERN COASTAL FLORIDA. POSSIBLE SHOWERS ARE
IN ISOLATED CELLS OF CLOUDS IN THE NORTHEASTERN YUCATAN
PENINSULA. SHOWERS ARE POSSIBLE IN THE ATLANTIC OCEAN TO THE
NORTH OF 25N BETWEEN 70W AND THE FLORIDA EAST COAST.
WEAK SURFACE ANTICYCLONIC FLOW MOVES AROUND A 1016 MB HIGH
PRESSURE CENTER THAT IS NEAR 27N88W.

THE CARIBBEAN SEA...
A SMALL AMOUNT OF MIDDLE LEVEL TO UPPER LEVEL CYCLONIC FLOW FROM
THE GULF OF MEXICO TROUGH SPILLS OVER INTO THE NORTHWESTERN
CARIBBEAN SEA...TO THE NORTH OF 18N TO THE WEST OF JAMAICA.
THE WESTWARD FLOW EVENTUALLY COMBINES WITH THE COMPARATIVELY
BROADER UPPER LEVEL SOUTHWESTERLY WIND FLOW THAT HAS BEEN IN
PLACE IN THE CARIBBEAN SEA FOR THE LAST FEW DAYS. THE UPPER
LEVEL SOUTHWESTERLY WIND FLOW IS ON THE WESTERN SIDE OF LARGE-
SCALE ANTICYCLONIC FLOW THAT COVERS THE ATLANTIC OCEAN.
IT IS POSSIBLE THAT AFTERNOON HEATING IN BROAD AND WEAK SURFACE
LOW PRESSURE MAY HAVE BEEN HELPING TO START SOME SHOWERS AND
THUNDERSTORMS IN THE EASTERN DOMINICAN REPUBLIC AND IN THE
COASTAL PLAINS OF NORTHERN PUERTO RICO...AND FARTHER AWAY IN
COASTAL AREAS OF NORTH CENTRAL VENEZUELA AND JUST TO THE WEST
OF LAKE MARACAIBO IN EXTREME NORTHWESTERN VENEZUELA.

THE ATLANTIC OCEAN...
PRACTICALLY ALL THE MIDDLE LEVEL TO UPPER LEVEL CYCLONIC FLOW
IN THE AREA IS ALONG AND TO THE NORTH OF 32N BETWEEN 35W AND
65W. THE TROUGH THAT IS TO THE NORTH OF THE AREA SUPPORTS THE
COLD FRONT THAT PASSES THROUGH 32N41W TO 26N50W 24N57W TO
A 1010 MB LOW PRESSURE CENTER THAT IS NEAR 26N63W. THE COLD
FRONT CONTINUES FROM THE LOW PRESSURE CENTER TO 23N69W. BROKEN
TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE SHOWERS ARE WITHIN
60 NM TO 90 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH
31N38W 25N50W 23N60W 20N66W. BROKEN TO OVERCAST MULTILAYERED
CLOUDS COVER THE AREA FROM 25N TO 30N BETWEEN 55W AND 70W.
BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA TO THE
SOUTH OF 32N BETWEEN 20W AND 70W. SURFACE ANTICYCLONIC FLOW
COVERS THE AREA TO THE NORTH OF 10N BETWEEN AFRICA AND 44W...
AROUND A 1018 MB HIGH PRESSURE CENTER THAT IS NEAR 26N28W.

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

$$
MT





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