[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 021759
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI MAY 02 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 2N10W 2N20W EQUATOR AT 34W THEN
1N43W INTO NE BRAZIL. CLUSTERS OF MODERATE/ISOLATED STRONG
CONVECTION COVER THE AREA FROM 3N TO 9N EAST OF 20W TO THE
AFRICAN COAST. A SFC TROUGH WAS ANALYZED IN THIS AREA ALONG
15W/16W ON THE 12Z SFC MAP. THERE SEEMS TO BE ENOUGH EVIDENCE TO
SUGGEST THAT THIS COULD BE A TROPICAL WAVE. SATELLITE IMAGERY
SHOWS A WELL DEFINED INVERTED V-PATTERN. THE HOVMOLLER DIAGRAM
ALSO INDICATES THE WWD PROPAGATION OF THIS SYSTEM DURING LAST
TWO DAYS...AND THE BAMAKO SOUNDING SHOWED THE PASSAGE OF THIS
TROUGH/WAVE BETWEEN APRIL 30 AND MAY 1ST. BASED ON THIS DATA AND
THE TIME OF THE YEAR...A TROPICAL WAVE WILL BE INTRODUCED ON THE
18Z MAP.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER-LEVEL HIGH LOCATED ON PACIFIC SIDE NEAR 12N93W EXTENDS
A RIDGE NWD COVERING MEXICO AND THE ENTIRE GULF. STRONG
SUBSIDENCE AND A DRY STABLE AIR MASS IS IN PLACE OVER MOST OF
THE GULF REGION WITH ONLY A FEW CLOUDS. A JET STREAM BRANCH WITH
CORE WINDS OF 90 KT EXTENDS FROM THE DEEP SOUTH TO THE SE
PORTION OF THE GULF AND WESTERN CUBA WHILE A SHORT WAVE TROUGH
IS MOVING ACROSS THE SE CONUS. AT THE SFC...A RIDGE ALSO
DOMINATES THE REGION EXTENDING FROM THE W ATLC ANCHORED BY A
1026 MB OFF THE NORTH CAROLINA COAST. THIS HIGH WILL KEEP A
BRISK SE TO S FLOW ACROSS THE GULF THROUGH TONIGHT BEFORE
DIMINISHING SAT. A COLD FRONT IS CURRENTLY MOVING ACROSS
SOUTH-CENTRAL TEXAS A NORTHERN COAHUILA MEXICO. THIS FRONT IS
FORECAST TO ENTER THE NW GULF WATERS LATE SAT AFTERNOON...AND
SHOULD EXTEND FROM THE FLORIDA BIG BEND TO JUST SOUTH OF CORPUS
CHRISTI TX SUN MORNING.

CARIBBEAN SEA...
BROAD UPPER RIDGE COVERS THE WESTERN CARIBBEAN AND CENTRAL
AMERICA BETWEEN COSTA RICA AND GUATEMALA. ANOTHER UPPER-LEVEL
RIDGE OVER NORTHERN SOUTH AMERICA EXTENDS WWD TO PANAMA. IN
BETWEEN...AN UPPER-LEVEL TROUGH FROM THE ATLC ENTERS THE
CARIBBEAN SEA THROUGH THE WINDWARD PASSAGE AND EXTENDS SW TO THE
SW CARIBBEAN. UPPER LEVEL TROPICAL MOISTURE IS BEING DRAWN FROM
SOUTH AMERICA TO OVER THE CENTRAL AND EASTERN CARIBBEAN WITH
SOME HIGH CIRRUS CLOUDS. THE TAIL END OF A COLD FRONT OVER THE
ATLC REACHES THE DOMINICAN REPUBLIC PRODUCING SOME CLOUDINESS
WITH EMBEDDED SHOWERS PARTICULARLY ALONG THE N COAST. THE SAN
JUAN DOPPLER RADAR IS DETECTING PART OF THIS ACTIVITY SHOWING
SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE ATLANTIC WATERS
NORTHWEST OF PUERTO RICO AS WELL AS SCATTERED TO NUMEROUS
SHOWERS AND TSTMS ACROSS THE INTERIOR AND WESTERN SECTIONS OF
PUERTO RICO. MOISTURE ASSOCIATED WITH THE FRONT IS FORECAST BY
THE COMPUTER MODELS TO AFFECT PUERTO RICO AND THE VIRGIN ISLANDS
THIS UPCOMING WEEKEND KEEPING THE LIKELIHOOD OF RAIN OVER THOSE
ISLANDS. SFC OBSERVATIONS ACROSS THE LESSER ANTILLES THIS
MORNING INDICATED PRETTY WELL THE PRESENCE OF A SFC TROUGH THAT
RUNS FROM 19N60W TO 14N63W. THIS TROUGH HAS AN AREA OF
CLOUDINESS WITH SOME TURNING AND SCATTERED SHOWERS JUST E OF
TROUGH AXIS. HIGH PRES OVER THE SW ATLC OFF THE NORTH CAROLINA
COAST IS PRODUCING 20 TO 25 KT NE WINDS THROUGH WINDWARD
PASSAGE. AN EARLIER QUIKSCAT PASS CONFIRMED THESE WINDS. LIGHT
TO MODERATE TRADE WINDS ARE BLOWING ACROSS THE BASIN.

ATLANTIC OCEAN...
SURFACE RIDGE COVERS THE W ATLC INTO THE E GULF ANCHORED BY A
1026 MB HIGH LOCATED OFF THE NORTH CAROLINA COAST. THIS FEATURE
IS PROVIDING MOSTLY FAIR WEATHER FOR THE W ATLC WATERS. A WEAK
UPPER LEVEL TROUGH EXTENDS FROM A CLOSED CYCLONIC CIRCULATION
NEAR 36N56W TO THE WINDWARD PASSAGE. THIS UPPER TROUGH SUPPORTS
A WEAK COLD FRONT THAT ENTERS THE FORECAST AREA NEAR 31N47W THEN
CONTINUES SW TO THE DOMINICAN REPUBLIC WHERE IS GENERATING SOME
SHOWER ACTIVITY. A SFC TROUGH...REMNANTS OF AN OLD FRONTAL
BOUNDARY CONTINUES TO LINGER OVER THE E-CENTRAL ATLC ALONG
31N26W 24N40W 17N52W. THE TAIL END OF THIS TROUGH LOOKS TO
BREAK-UP AND IS NOW OVER THE LESSER ANTILLES. A WEAK 1018 MB
HIGH IS AHEAD OF THIS TROUGH CENTERED NEAR 21N30W. A MAINLY
ZONAL FLOW DOMINATES THE REMAINDER OF THE ATLANTIC DISCUSSION
AREA WHILE AN UPPER RIDGE IS INLAND OVER WESTERN AFRICA...
ESPECIALLY AT MIDDLE LEVELS.

$$
GR






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