[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182335
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT MAR 18 2006

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

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

...ITCZ...
ITCZ AXIS EXTENDS FROM NEAR THE COAST OF AFRICAN OVER SOUTHERN
GHANA AND THE IVORY COAST W ALONG 4.5N10W 5N20W 3N30W 5N46W TO
THE SOUTH AMERICAN COAST NEAR 4N51W. WIDELY SCATTERED MODERATE
CONVECTION IS WITHIN 30 NM OF THE AXIS BETWEEN 12W-20W.
SCATTERED MODERATE CONVECTION IS WITHIN 30 NM OF THE AXIS FROM
29W-32W. CONVECTION ALONG THE ITCZ NEAR THE COAST OF SOUTH
AMERICA HAS WEAKENED. HOWEVER...MULTILAYERED CLOUDINESS WITH
PATCHES OF RAIN/SHOWERS REMAINS FROM THE EQ TO 6N W OF 44W.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER LEVEL RIDGE REMAINS ACROSS THE GULF OF MEXICO.  RIDGE
BEGINS OVER THE E PACIFIC WATERS SOUTH OF THE GULF OF
TEHUANTEPEC AND EXTENDS ALONG 22N93W ACROSS SOUTHERN
LOUISIANA...THEN WELL NORTHWARD INTO U.S. MIDWEST REGION. BROAD
ANTICYCLONIC FLOW COVERS THE ENTIRE GULF OF MEXICO. RIDGE IS
FORECAST TO MOVE SLOWLY EASTWARD DURING THE NEXT 24-48 HOURS AS
A TROUGH OVER THE SW U.S. MOVES EASTWARD.

STATIONARY FRONT THAT EXTENDS OFF THE TEXAS COAST NEAR THE BAY
CITY/FREEPORT AREA HAS BECOME A LITTLE BETTER DEFINED TODAY. THE
FRONT EXTENDS ESE INTO THE CENTRAL GULF OF MEXICO NEAR 27N90W.
CLOUDY AND BREEZY CONDITIONS WITH E-NE WINDS OF 20-25 KT ARE
FOUND ALONG THE UPPER TEXAS AND LOUISIANA COASTS N OF THE FRONT.
NUMERICAL MODELS INDICATE THAT THE FRONT WILL BEGIN TO LIFT
SLOWLY NORTHWARD DURING THE NEXT 24-36 HOURS. HOWEVER...MODELS
LIKELY A LITTLE FAST IN MOVING IT INTO SOUTHERN LOUISIANA.
SCATTERED LOW CLOUDS ARE SEEN OVER THE THE REMAINDER OF THE
GULF. WINDS ARE FORECAST TO BECOME SELY ACROSS THE AREA. WINDS
EXPECTED TO INCREASE TO 20-25 KT OVER THE ENTIRE WESTERN GULF
WITHIN THE NEXT 24 HOURS.

CARIBBEAN SEA...
MAINLY SW-W UPPER LEVEL FLOW COVERS THE CARIBBEAN. THE FAR NW
PORTION IS UNDER THE INFLUENCE OF THE GULF OF MEXICO RIDGE
WITH NWLY FLOW SEEN NW OF LINE FROM W CUBA TO GULF OF HONDURAS.
WEAK UPPER LEVEL TROUGH THAT EXTENDS FROM HISPANIOLA TO SW
CARIBBEAN NEAR COSTA RICA DIVIDES THE WESTERLY UPPER FLOW
FROM SWLY FLOW EAST OF THE TROUGH. MODERATE TO STRONG SUBSIDENCE
COVERS THE ENTIRE CARIBBEAN SEA. WITH THE HEATING OF THE DAY...A
FEW SHOWERS/POSSIBLE THUNDERSTORMS WERE SEEN OVER WESTERN PUERTO
RICO...HISPANIOLA...AND JAMAICA. THESE SHOULD DISSIPATE EARLY
THIS EVENING. AN AREA OF BROKEN LOW CLOUDS WITH ISOLATED TO
WIDELY SCATTERED SHOWERS IS SEEN OVER THE ATLC APPROACHING
THE WINDWARD ISLANDS. OVER THE REMAINDER OF THE CARIBBEAN
SEA...FAIR WEATHER CUMULUS CLOUDS DOT THE AREA.

ATLANTIC OCEAN...
BROAD MID/UPPER LEVEL TROUGH COVERS THE WESTERN ATLC N OF 20N
W OF 50W. SHORTWAVE TROUGH IS SEEN MOVING QUICKLY ENE ALONG THE
LINE 32N58W 27N59W TO 23N63W. THE TROUGH IS INTERACTING WITH THE
WESTERN PORTION OLD FRONTAL BOUNDARY ALONG 29N/30N BETWEEN
40W-58W. THIS IS PRODUCING AND AREA OF SCATTERED THUNDERSTORMS
WITHIN 60 NM OF LINE FROM 32N52W TO 27N56W. OVERNIGHT...
ADDITIONAL SHOWER/THUNDERSTORM WILL LIKELY FORM  ALONG THE OLD
BOUNDARY. WEST OF THE SHORTWAVE TROUGH SUBSIDENCE/DRY AIR
COVER THE WESTERN ATLC. SEVERAL WEAK SURFACE BOUNDARIES ARE SEEN
OVER THE WESTERN ATLC...BUT THEY ARE VERY DIFFICULT TO LOCATE.
THE MOST PRONOUNCED FEATURE IS A WEAK 1015 MB LOW THAT IS
CENTERED NEAR 29.5N 77W. THIS LOW IS MOVING SLOWLY E-SE. HIGH
PRES RIDGE THAT EXTENDS OFF THE SE U.S. COAST WILL BUILD SEWD
SUN WITH THESE WEAK FEATURES PUSHING SEWD BETWEEN BERMUDA AND
THE SE BAHAMAS.

BROAD MID/UPPER LEVEL RIDGE COVERS THE AREA N OF 22N BETWEEN
32N-50W. E OF 32W THE FLOW BECOMES NEARLY ZONAL...EXCEPT FOR A
WEAK TROUGH THAT EXTENDS FROM 26N27W TO 21N35W.

OVER THE TROPICAL ATLC...A WELL DEFINED MID/UPPER LEVEL HIGH
IS CENTERED NEAR 4N41W. THE HIGH IS PRODUCING ANTICYCLONIC FLOW
ACROSS THE AREA S OF 20N W OF 28W.

$$
BROWN




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