[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 300552
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT 30 APR 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...THE ITCZ...

ITCZ IS CENTERED ALONG 4N1W 6N15W 3N30W 5N52W.  SCATTERED STRONG
CONVECTION WITHIN 75 NM EITHER SIDE OF AXIS BETWEEN 4W-16W AND
WITHIN 60 NM OF AXIS FROM 30W-40W.

...DISCUSSION...
GULF OF MEXICO...
MODERATE TO STRONG RETURN FLOW HAS DEVELOPED ACROSS THE ENTIRE
GLFMEX AHEAD OF AN APPROACHING COLD FRONT PUSHING SWD OVER
TEXAS. COLD FRONT WILL INITIALLY BE MOISTURE STARVED AS IT MOVES
OFF THE SE COAST OF TEXAS DURING THE NEXT FEW HOURS.
HOWEVER...EXPECT INCREASING LOW LEVEL MOISTURE POOLING AND
IMPROVING UPPER LEVEL DYNAMICS TO ALLOW A DEVELOPING LINE OF
SHOWERS AND THUNDERSTORMS...MAINLY N OF 27N...AROUND MIDDAY AS
THE FRONT PUSHES INTO THE N CENTRAL GULF.  MOISTURE AND DYNAMICS
REALLY COME TOGETHER SAT AFTERNOON AND EVENING OVER THE NE GULF
AND N FLORIDA WITH NUMEROUS SHOWERS/THUNDERSTORMS LIKELY. THE
UPPER TROUGH BEGINS TO LIFT NEWD SUNDAY WITH DECREASING UPPER
SUPPORT AND SHOWERS/THUNDERSTORMS ALONG THE FRONT AS IT BEGINS
TO PULL UP STATIONARY AND WEAKEN IN THE VICINITY OF LAKE
OKEECHOBEE BY LATE SUN. EARLIER VISIBLE SATELLITE IMAGERY SHOWED
A LARGE AREA OF SMOKE MOVING NWD FROM S MEXICO AND CENTRAL
AMERICA ACROSS W GULF W OF 90W INTO THE TEXAS AND LOUISIANA
COAST.

CARIBBEAN SEA...
WELL DEFINED MIDDLE TO UPPER LEVEL RIDGE EXTENDS FROM N PORTIONS
OF S AMERICA NW OVER CENTRAL AMERICA INTO S MEXICO.  FARTHER
E...MIDDLE TO UPPER LEVEL TROUGH IS DIGGING SWD OVER THE W ATLC
INTO THE NE CARIBBEAN.  THIS PATTERN IS PRODUCING INCREASINGLY
NW FLOW AND CONFLUENCE ALOFT.  AT THE LOWER LEVELS...MOISTURE
REMAINS LARGELY LIMITED OVER ALL BUT THE FAR E CARIBBEAN WHERE
SCATTERED SHOWERS ARE NOTED N OF 15N E OF 67W INCLUDING THE
LEEWARD ISLANDS AND PUERTO RICO.  MOISTURE AND THE PROBABILITY
FOR SHOWERS WILL REMAIN HIGHEST OVER THE E CARIBBEAN THROUGH THE
WEEKEND WITH GENERALLY DRY CONDITIONS ELSEWHERE OVER THE CENTRAL
AND W CARIBBEAN.

ATLANTIC OCEAN...
MIDDLE TO UPPER LEVEL RIDGE BUILDING EWD OFF THE E COAST OF THE
UNITED STATES CONTINUES TO PRODUCE DRY/TRANQUIL CONDITIONS
ACROSS MUCH OF THE W ATLC. THE ONLY CLOUDINESS OF NOTE IS A
FIELD OF STRATOCUMULUS CLOUDS NE OF THE BAHAMAS.  OVER THE
CENTRAL ATLC...A DIGGING MIDDLE TO UPPER LEVEL TROUGH NEAR 50W
IS PRODUCING CLOUDINESS AND SCATTERED SHOWERS/ISOLATED MODERATE
CONVECTION N OF 20N BETWEEN 49W-53W.  THE ATTENDANT COLD FRONT
HAS BECOME DIFFUSE OVER THE LAST 24 HOURS CURRENTLY EXTENDING
SWD FROM A 1014 MB LOW NEAR 33N59W THROUGH 25N62W TO 20N66W.
THE UPPER TROUGH SHOULD AMPLIFY SEWD DURING THE NEXT 24 HOURS
WITH ASSOCIATED SCATTERED SHOWERS/THUNDERSTORMS N OF 20N BETWEEN
40W-50W BY SUN.  A DEEP LAYERED TROUGH WELL N OF THE AREA
EXTENDS A COLD FRONT SWD E OF THE AZORES ENTERING THE AREA ALONG
32N22W TO 23N35W.  WITH NEARLY ZONAL FLOW ALOFT ACROSS THE
AREA...THERE IS LITTLE UPPER SUPPORT FOR THIS FEATURE AND NO
SIGNIFICANT CLOUDS/PRECIPITATION.  FARTHER S...A WELL DEFINED
E/W ORIENTED RIDGE NOW EXTENDS ACROSS THE ENTIRE TROPICAL ATLC S
OF 15N.  THE ITCZ IS MOST ACTIVE BETWEEN 30W-40W AND ALONG THE
SW COAST OF AFRICA E OF 15W.

$$
JR




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