[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 071744
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON APR 07 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
1745 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 3N10W 4N18W 1N30W 1N40W CROSSING THE
EQUATOR AT 45W INTO NE BRAZIL. 2N52W. CLUSTERS OF SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION ARE WITHIN 130 NM N OF
AXIS AND E OF 18W. SIMILAR CONVECTION IS FOUND WITHIN 150-180 NM
EITHER SIDE BETWEEN 35W-42W AND NEAR 6N22W. STRONG CONVECTION IS
OVER EASTERN LIBERIA AND SOUTHERN COTE D'IVOIRE.

...DISCUSSION...
GULF OF MEXICO...
A SHORT WAVE TROUGH OVER THE CENTRAL GULF SUPPORTS A SFC TROUGH
THAT HAS DEVELOPED OVER THE SAME REGION THIS MORNING. AT 1500
UTC...THE TROUGH RUNS FROM 28N90W TO A 1007 MB SFC LOW LOCATED
OVER THE BAY OF CAMPECHE NEAR 19N93W. SATELLITE IMAGERY AND
LIGHTNING DATA REVEAL AN AREA OF STRONG CONVECTION ASSOCIATED
WITH THIS SFC TROUGH. WEAK CYCLONIC TURNING IS NOTED IN THIS
AREA OF SHOWERS AND TSTMS. UPPER DIFFLUENCE AHEAD OF THE ABOVE
MENTIONED UPPER TROUGH IS ENHANCING THIS ACTIVITY THAT IS NOW
AFFECTING THE CENTRAL GULF FROM 23N TO 28N BETWEEN 86W AND 91W.
ACCORDING TO THE COMPUTER MODELS...THIS TROUGH WILL MOVE EWD AND
WILL PROBABLY BRING ANOTHER ROUND OF SHOWERS AND TSTMS OVER THE
STATE OF FLORIDA FOR THE THIRD NIGHT IN A ROW. THE UPPER TROUGH
WILL BE NEAR THE WEST COAST FLORIDA EARLY TUESDAY. THE REMAINDER
OF THE GULF REMAINS PRETTY TRANQUIL WITH MAINLY LIGHT SE WINDS E
OF THE TROUGH AXIS AND NE WINDS W OF THE TROUGH AXIS. LOOKING
AHEAD... THE RETURN FLOW IS FORECAST TO INCREASE THU AHEAD OF
THE NEXT COLD FRONT WHICH WILL MOVE OFF THE TEXAS AND LOUISIANA
COASTS FRIDAY.

CARIBBEAN SEA...
A WEAK UPPER TROUGH REMAINS OVER THE NW CARIBBEAN AND THE GULF
OF HONDURAS WHILE A BROAD UPPER RIDGE ANCHORED ON A HIGH LOCATED
SE OF THE TRINIDAD AND TOBAGO ISLANDS COVERS THE REMAINDER OF
THE BASIN. THESE UPPER FEATURES ARE PRODUCING MAINLY A ZONAL
FLOW OVER THE CARIBBEAN SEA. MODERATE TO STRONG SUBSIDENCE AND
DRY STABLE AIR COVERS A GOOD PORTION OF THE AREA. A PLUME OF
MOISTURE IS BEING DRAWN NORTHWARD FROM NORTHERN COLOMBIA TO
SOUTH OF HISPANIOLA AND PUERTO RICO INTO THE LEEWARD ISLANDS. AS
USUAL...PATCHES OF LOW LEVEL MOISTURE DRIVEN BY THE TRADE WINDS
ARE SEEN OVER THE EASTERN CARIBBEAN. SOME OF THEM ARE CURRENTLY
AFFECTING HISPANIOLA. OTHERWISE...A 1025 MB SURFACE HIGH
PRESSURE LOCATED NEAR 28N61W IS PROVIDING A CONTINUED FRESH
TRADE WIND FLOW ACROSS THE EASTERN AND CENTRAL PART OF THE
BASIN. AN EARLIER QUIKSCAT PASS SHOWED ELY WINDS OF 20 TO 25
KT...PARTICULARLY JUST OFFSHORE THE COLOMBIAN COAST. THE SURFACE
RIDGE OVER THE WEST-CENTRAL ATLANTIC SHOULD GRADUALLY WEAKEN
WHILE SHIFTING SE...WHICH SHOULD CAUSE THE STRONG TRADE WIND
FLOW ACROSS THE AREA TO RELAX.

ATLANTIC OCEAN...
THE SHORT WAVE TROUGH THAT BROUGHT STRONG SHOWERS AND TSTMS TO
SOUTH FLORIDA LAST NIGHT IS LIFTING NE AND MOVING OUT OF AREA.
HOWEVER...AN AREA OF SHOWERS AND TSTMS REMAIN OVER THE WESTERN
ATLC W OF 75W...INCLUDING THE NW BAHAMAS AND PARTS OF CENTRAL
CUBA. LIGHTNING DATA INDICATES SCATTERED TSTMS OVER THIS AREA. A
1012 MB LOW IS ANALYZED JUST E OF NE FLORIDA WITH A COLD FRONT
EXTENDING SW ACROSS THE LAKE OKEECHOBEE AND SOUTH CENTRAL
FLORIDA. THIS FRONT WILL BE MOVING THROUGH MAINLAND SOUTH
FLORIDA LATER TODAY AS A SURFACE LOW PRESSURE SYSTEM MOVES NE
OVER THE W ATLC. BROAD UPPER HIGH COVERS THE REMAINDER OF THE W
ATLC AND OVER THE CENTRAL ATLC CENTERED NEAR 28N68W WITH A
SURFACE RIDGE COVERING THE AREA W OF 40W ANCHORED BY A 1023 MB
HIGH NEAR 28N61W. BROAD UPPER TROUGH COVERS THE E ATLC N OF 27N
E OF 50W TO OVER W AFRICA. THE ATTENDANT COLD FRONT ENTERS THE
FORECAST REGION NEAR 31N13W...THEN CROSSES THE CANARY ISLANDS TO
17N38W AS A DYING FRONT. BROAD SURFACE CYCLONIC FLOW COVERS THE
AREA N OF ABOUT 24N...DIRECTLY BEHIND THE COLD FRONT. TIGHT PRES
GRADIENT BETWEEN A COMPLEX SFC LOW OVER THE E ATLC AND THE
PREVIOUSLY MENTIONED SFC RIDGE IS PRODUCING A SWATH OF MAINLY
WLY WINDS OF 20 TO 30 KT N OF 24N BETWEEN 20W AND 45W. BROAD E/W
UPPER RIDGE COVERS THE TROPICS.

$$
GR






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