[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271650
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI APR 27 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1615 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 4N6W 3N9W 3N23W CROSSING THE EQUATOR
NEAR 38W TO INLAND OVER SOUTH AMERICA TO 1S52W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS N OF 3N TO INLAND OVER SW
AFRICA BETWEEN 5W-10W. CLUSTERS OF SIMILAR CONVECTION ARE S OF
6N W OF 45W TO INLAND OVER SOUTH AMERICA.

...DISCUSSION...

GULF OF MEXICO...
SLOW MOVING COLD FRONT EXTENDS ACROSS CENTRAL GEORGIA AND THE
FLORIDA PANHANDLE INTO THE GULF NEAR 30N84W TO 26N89W. THIN LINE
OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE SE OF THE FRONT
EXTENDING ACROSS NE FLORIDA FROM JACKSONVILLE THROUGH TAMPA INTO
THE GULF TO NEAR 26N86W. THIS FRONT IS ASSOCIATED WITH A
SHORTWAVE UPPER TROUGH MOVING ACROSS THE FAR SE US INTO THE W
ATLC DIPPING INTO THE NW CARIBBEAN. THE BULK OF THE ENERGY WITH
THIS SHORTWAVE IS N OF THE REGION. A SURFACE RIDGE IS BUILDING
BEHIND THE FRONT ANCHORED BY A 1019 MB HIGH OVER N LOUISIANA.
THE REMAINDER OF THE GULF IS DOMINATED BY AN UPPER RIDGE THAT
EXTENDS FROM AN UPPER HIGH IN THE E PACIFIC REGION ACROSS S
MEXICO THROUGH THE BAY OF CAMPECHE TO OVER THE LOWER MISSISSIPPI
VALLEY. THIS RIDGE IS ADVECTING TROPICAL MOISTURE ACROSS MEXICO
AND TEXAS TO OVER THE NW GULF BRINGING SCATTERED SHOWERS N OF
26N W OF 95W. THE REMAINDER OF THE GULF IS UNDER FAIR SKIES WITH
DRY AIR IN PLACE...LITTLE CHANCE OF SHOWERS. THE FRONT WILL
BEGIN TO WEAKEN AS IT MOVES ACROSS THE FLORIDA PENINSULA AND
MOVE OUT OF THE GULF ON SUN.

CARIBBEAN SEA...
THE SHORTWAVE UPPER TROUGH OVER THE E GULF OF MEXICO DIPS INTO
THE NW CARIBBEAN N OF 17N W OF 80W BRINGING DRY AIR TO OVER THE
AREA. THE REMAINDER OF THE CARIBBEAN IS UNDER A BROAD UPPER
RIDGE ANCHORED OVER SOUTH AMERICA WITH THE AXIS EXTENDING ACROSS
THE ABC ISLANDS TO OVER HISPANIOLA. THIS RIDGE IS ADVECTING
TROPICAL MOISTURE ACROSS PANAMA AND COSTA RICA GIVING THE AREA S
OF 13N FROM 75W-80W SCATTERED SHOWERS/THUNDERSTORMS WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 11N FROM 80W-84W.
MODERATE/STRONG EASTERLY TRADE WINDS ARE BRINGING IN LOW LEVEL
MOISTURE WITH ISOLATED SHOWERS ACROSS THE E CARIBBEAN E OF 75W
AND A SMALL AREA OF SCATTERED SHOWERS FROM 13N-17N BETWEEN
60W-65W INCLUDING THE CENTRAL LESSER ANTILLES. THE REMAINDER OF
THE AREA IS UNDER FAIR SKIES.

ATLANTIC...
THE SHORTWAVE UPPER TROUGH OVER THE GULF OF MEXICO EXTENDS OVER
THE FAR W ATLC W OF 77W. SHOWER ACTIVITY WILL MOVE OFF THE
FLORIDA PENINSULA OVER THE NEXT FEW HOURS INTO THE FLORIDA
COASTAL WATERS. UPPER RIDGE COVERING THE CARIBBEAN EXTENDS AN
AXIS ACROSS HISPANIOLA INTO THE W ATLC TO BEYOND 32N68W. A SMALL
AREA OF DIFFLUENCE IS GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WITHIN 75 NM OF LINE FROM 25N73W ACROSS THE
BAHAMAS TO OVER E CUBA NEAR 20N76W. AN UPPER TROUGH EXTENDS FROM
THE CENTRAL ATLC THROUGH 31N45W SW TO UPPER LOW NEAR 24N61W.
THIS IS A RATHER BENIGN FEATURE PRODUCING ONLY ISOLATED SHOWERS
WITHIN 90 NM OF THE TROUGH AXIS. THIS TROUGH WAS PREVIOUSLY
ASSOCIATED WITH A DEEP LAYERED TROUGH OVER THE NE ATLC THAT HAS
MOVED EASTWARD NOW COVERING THE AREA N OF 23N E OF 25W. A
REMNANT SURFACE TROUGH IS OVER THE E/CENTRAL ATLC EXTENDING
ACROSS THE AZORES THROUGH 32N31W SW TO 28N41W. POSSIBLE ISOLATED
SHOWERS ARE WITHIN 60 NM OF THE SURFACE TROUGH. THE REMAINDER OF
THE ATLC IS DOMINATED BY A BROAD SURFACE RIDGE WITH A 1027 MB
HIGH IN THE W ATLC NEAR 31N58W AND A WEAKER 1024 MB HIGH IN THE
E ATLC NEAR 31N25W GIVING THE REMAINDER OF THE ATLC FAIR
WEATHER. THE SURFACE RIDGE OVER THE ATLC WILL REMAIN ACROSS THE
AREA WITH SOME WEAKNESS WITH THE APPROACHING FRONT CURRENTLY IN
THE GULF OF MEXICO.

$$
WALLACE


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