[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 131739
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI 13 MAY 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 45W S OF 13N MOVING W 10-15 KT. THE WAVE
REMAINS VERY WEAK AND DIFFICULT TO LOCATE IN SATELLITE IMAGERY.
THE POSITION IS BASED ON EXTRAPOLATED MOTION DURING THE PAST 24
HOURS. THERE IS NO CONVECTIVE ACTIVITY ASSOCIATED WITH THE WAVE.

TROPICAL WAVE IS LOCATED ACROSS THE EAST CARIBBEAN SOUTH OF
PUERTO RICO AND THE VIRGIN ISLANDS ALONG 65W/66W S OF 15N
MOVING W NEAR 15 KT. SCATTERED SHOWERS/THUNDERSTORMS ARE
DEVELOPING NEAR THE N PORTION OF THE WAVE...S OF HISPANIOLA AND
CUBA. ADDITIONAL CONVECTIVE ACTIVITY IS OCCURRING OVER SW
VENEZUELA. SOME OF THE MOISTURE ASSOCIATED WITH THE WAVE WILL
LIKELY MOVE NW INTO THE BROAD TROUGH LOCATED NORTH OF HISPANIOLA
AND PUERTO RICO.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N13W 4N21W 4N27W 5N36W 4N51W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS LOCATED
SOUTH OF THE ITCZ OFF THE SW COAST OF AFRICA. THE CONVECTION
IS WITHIN 90 NM OF LINE ALONG 4N8W 5N13W 6N17W. THERE IS NO
SIGNIFICANT CONVECTIVE ACTIVITY ALONG THE REMAINDER OF
THE ITCZ AXIS.

...DISCUSSION...

GULF OF MEXICO...
WEAK SHORTWAVE TROUGH SEEN IN WATER VAPOR IMAGERY...IS MOVING
NE ACROSS SE LOUISIANA...AHEAD OF A MUCH STRONGER DEEP LAYERED
TROUGH OVER THE CENTRAL UNITED STATES.  THE SHORTWAVE TROUGH
IS AIDING IN THE DEVELOPMENT OF WIDELY SCATTERED SHOWERS
AND POSSIBLE THUNDERSTORMS OVER SE LOUISIANA AND THE N CENTRAL
GULF OF MEXICO. THE SHORTWAVE TROUGH IS FORECAST TO MOVE NE
OVER THE SE U.S. WHILE THE DEEP LAYERED TROUGH SLOWLY MOVES
EAST DURING THE NEXT 24 HOURS. AT THE SURFACE... HIGH PRES NE OF
THE AREA EXTENDS A RIDGE ALONG THE N GULF COAST WITH AN EAST TO
SOUTHEAST WIND FLOW OVER THE REGION. THE SOUTHEASTERLY FLOW IS
ADVECTING LOW LEVEL GULF MOISTURE INTO TEXAS AND LOUISIANA AND
FARTHER NORTHWARD INTO THE CENTRAL PLAINS. SMOKE AND HAZE FROM
AGRICULTURE FIRES REMAINS EVIDENT ACROSS EASTERN MEXICO AND THE
WESTERN GULF OF MEXICO. SURFACE STATIONS IN THE AREA ARE
GENERALLY REPORTING VISIBILITIES OF 5-6 NM.

WESTERN/CENTRAL ATLANTIC AND THE CARIBBEAN....
THE MOST STRIKING FEATURE ACROSS THE AREA TODAY IS A LARGE
BAND OF CLOUDINESS/SHOWERS AND THUNDERSTORMS THAT STRETCHES
FROM THE CENTRAL ATLANTIC ACROSS THE GREATER ANTILLES TO THE
SW CARIBBEAN. ONE OF THE MAIN CULPRITS FOR THIS AREA OF WEATHER
IS A MID/UPPER LEVEL TROUGH THAT IS LOCATED ACROSS THE WESTERN
ATLANTIC FROM 27N70W ACROSS THE CENTRAL BAHAMAS...CENTRAL CUBA
AND INTO THE NW CARIBBEAN SEA.  A BROAD JET WITH WINDS OF 60-80
KT EXTENDS SE OF THE TROUGH ACROSS EASTERN CUBA AND INTO THE
WEST ATLC...THE JET STRENGTHENS TO 90-120 KT ALONG THE LINE
25N67W TO BEYOND 28N50W.

UPPER LEVEL DIFFLUENT FLOW SE OF THE TROUGH AND JET ARE
INTERACTING WITH A SURFACE TROUGH THAT EXTENDS ALONG 25N50W
21N60W TO NEAR THE WINDWARD PASSAGE. A SEPARATE SURFACE TROUGH
HAS FORMED OVER THE WESTERN CARIBBEAN ALONG 81W SOUTH OF 17N.
CLUSTERS OF SHOWERS AND THUNDERSTORMS EXTEND FROM NE OF THE
LEEWARD ISLANDS ACROSS PUERTO RICO...HISPANIOLA...EASTERN
CUBA...INTO THE WEST AND SW CARIBBEAN. THE STRONGEST
THUNDERSTORMS ARE CURRENTLY LOCATED OVER THE SW CARIBBEAN
S OF 14N W OF 77W. FORECAST MODELS INDICATE THAT WEAK LOW PRES
MAY FORM OVER THE SW CARIBBEAN SEA.  HOWEVER...UPPER LEVEL WINDS
APPEAR UNFAVORABLE FOR ANY SIGNIFICANT DEVELOPMENT DURING THE
NEXT COUPLE DAYS. IN ANY CASE...ENHANCED RAINS WILL LIKELY
CONTINUE ACROSS JAMAICA...HISPANIOLA AND PUERTO RICO. THIS HAS
THE POTENTIAL TO PRODUCE LIFE THREATENING FLASH FLOODS AND
MUDSLIDES ESPECIALLY OVER HISPANIOLA.

OVER THE REMAINDER OF THE W ATLANTIC AND FLORIDA...A SMALL
ANTICYCLONIC CIRCULATION IS LOCATED NW OF THE TROUGH OFF THE
COAST OF JACKSONVILLE. MODERATE TO STRONG SUBSIDENCE IS NW
OF THE TROUGH OVER FLORIDA AND THE NW BAHAMAS.

REMAINDER ATLANTIC...
WESTERLY ZONAL FLOW COVERS MUCH OF THE REMAINDER OF THE
ATLANTIC.THE ONLY EXCEPTION IS A WEAK MID/UPPER LEVEL
TROUGH THAT EXTENDS ALONG THE COAST OF AFRICA ALONG 15N17W
9N25W TO 5N35W. MID/HIGH LEVEL CLOUDINESS FROM THE CARIBBEAN
AND W ATLC IS BEING BLOW EASTWARD IN THE ZONAL FLOW N OF 20N
TO ABOUT 30W. AT THE SURFACE...STRONG SURFACE RIDGE COVERS THE
E ATLC N OF 20N E OF 40W TO THE COAST OF AFRICA.

$$
BROWN


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