[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 020008
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE APR 01 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N11W 3N20W CROSSING THE EQUATOR
NEAR 30W TO 1S45W. THE ITCZ IN THE ATLC REMAINS VERY ACTIVE THIS
EVENING. SCATTERED TO NUMEROUS STRONG CONVECTION IN CLUSTERS
ARE NOTED WITHIN 45-90 NM OF A LINE FROM THE EQUATOR AT 14W TO
2N22W. A LARGER AREA OF SCATTERED MODERATE ISOLATED STRONG
CONVECTION WAS NOTED WITHIN 150-180 NM EITHER SIDE OF THE AXIS
BETWEEN 17W AND 30W...EXTENDING TO 4S BETWEEN 27W AND 30W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN
180 NM N OF THE AXIS W OF 42W TO THE COAST OF SOUTH AMERICA.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER LEVEL ANTICYCLONE OVER THE E PACIFIC NEAR 14N103W
STILL EXERTING AN INFLUENCE OVER OLD MEXICO AND THE GULF OF
MEXICO. A SHEARING UPPER LEVEL SHORTWAVE TROUGH EXTENDS FROM THE
MID-ATLC STATES SWWD TO THE LOWER MISSISSIPPI RIVER VALLEY/NW
LOUISIANA. DIFLUENT FLOW BETWEEN THE UPPER HIGH AND THE SHEARED
TROUGH WAS INDICATED ALONG THE GULF COAST AND NE GULF INTO
FLORIDA. THIS AREA OF FLOW COUPLED WITH A 75-90 KT JET STREAK
WAS AIDING IN MAINTAINING SCATTERED SHOWERS AND THUNDERSTORMS
OVER PORTIONS OF LOUISIANA AND THE CENTRAL FLORIDA PENINSULA
BETWEEN TAMPA BAY...ORLANDO AND LAKE OKEECHOBEE EXTENDING SWD TO
THE NAPLES AND FT MYERS AREAS. THE STORMS OVER LOUISIANA WERE
OCCURRING ALONG AND AHEAD OF A COLD FRONTAL BOUNDARY IN THE AREA
WHILE THE STORMS OVER FLORIDA WERE BEING GENERATED BY SEABREEZE
CONVERGENCE. A SURFACE RIDGE ANCHORED IN THE NW ATLC EXTENDS WWD
ACROSS THE E GULF RESULTING IN SE SURFACE FLOW OVER MOST OF THE
GULF BANKING SCATTERED TO BROKEN/OVERCAST LOW CLOUDS ALONG THE N
GULF COAST. OTHERWISE THE REMAINDER OF THE GULF REMAINS CLEAR
THIS EVENING WITH SOME ISOLATED SHOWERS MOVING OFF THE W COAST
OF CUBA.

CARIBBEAN SEA...
THE FAR SWWD EXTENT OF AN UPPER TROUGH OVER THE ATLC EXTENDS SWD
OVER THE CENTRAL CARIBBEAN TO A BASE NEAR 12N79W. A DEVELOPING
CLOSED LOW/CYCLONIC CIRCULATION WAS JUST S OF HAITI NEAR 17N73W.
THIS FEATURE WAS GENERATING A LARGE AREA OF MULTILAYERED CLOUDS
WITH EMBEDDED SCATTERED SHOWERS ACROSS HISPANIOLA AND E CUBA
EXTENDING NE OVER THE BAHAMAS. A NWLY JET STREAK WAS SWEEPING
INTO THE BACK OF THE TROUGH ACROSS THE FLORIDA PENINSULA AND N
CUBA. THE REMAINDER OF THE AREA IS DOMINATED BY LARGE UPPER
LEVEL RIDGES OVER THE E PACIFIC AND THE TROPICAL ATLC WITH NWLY
FLOW ALOFT OVER THE CARIBBEAN W OF 78W AND A BROAD AREA OF
W TO SW UPPER FLOW E OF 70W. THE MOST SIGNIFICANT SURFACE
FEATURE IS A SURFACE TROUGH...POSSIBLE PRE-SEASON TROPICAL WAVE
EXTENDING FROM PUERTO RICO SWD TO NEAR 12N68W...MOVING WWD AT
20 KT. THIS FEATURE IS BECOMING INCREASINGLY INFLUENCED BY
THE CYCLONIC CIRCULATION OVER HAITI WITH AN INCREASE IN SCATTERED
SHOWER AND ISOLATED THUNDERSTORM ACTIVITY OVER THE E-CENTRAL
CARIBBEAN N OF 15N BETWEEN 65W AND 71W. OVERALL SHOWER AND
THUNDERSTORM ACTIVITY SHOULD BE ON THE INCREASE OVER HISPANIOLA
AND E CUBA OVER THE NEXT 24 HOURS. ELSEWHERE OVER THE CARIBBEAN
STRONG SUBSIDENCE AND DRY STABLE AIR WAS NOTED.

ATLANTIC OCEAN...
A STRONGLY POSITIVELY TILTED TROUGH EXTENDS ACROSS THE CENTRAL
ATLC THROUGH 32N38W 28N53W AND CONNECTS TO THE DEVELOPING
CYCLONIC CIRCULATION IN THE CARIBBEAN JUST S OF HAITI. MODERATE
TO STRONG SUBSIDENCE WAS OCCURRING IN THE WAKE OF THE TROUGH
OVER THE ATLC N OF 22N BETWEEN 40W AND 70W. ASSOCIATED SURFACE
COLD FRONT ENTERING THE REGION NEAR 32N35W AND EXTENDED SW
THROUGH 25N45W TO 23N56W. SCATTERED SHOWERS ARE WITHIN 120 NM OF
THE FRONT N OF 30N. STRONGLY DIFFLUENT FLOW WAS NOTED OVER THE
FAR W ATLC W OF 73W EXTENDING WWD TO THE SE CONUS. THIS FLOW WAS
AIDING IN MAINTAINING SCATTERED THUNDERSTORMS OVER THE FLORIDA
PENINSULA AND FROM 30N TO 32N BETWEEN 78W AND 80W AS WELL AS
ALONG THE GA AND SC COAST. BROAD UPPER RIDGE ANCHORED DEEP IN
THE TROPICS COVERS THE TROPICAL ATLC S OF 20N E OF 60W AND WAS
BEING SUPPRESSED ALONG THE NRN PERIPHERY BY THE TROUGH NOTED
ABOVE. OTHER THAN THE COLD FRONT...THE ONLY OTHER MAJOR SURFACE
FEATURE IN THE ATLC WAS A SPRAWLING 1036 MB HIGH NEAR 34N58W
WHICH DOMINATED THE AREA NW OF THE COLD FRONT. BROAD SURFACE
RIDGE COVERS THE E ATLC E OF THE FRONT ANCHORED BY A 1030 MB
HIGH OFF THE NW COAST OF SPAIN.

$$
COBB




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