[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 020003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU MAR 01 2007

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 5N9W 1N20W EQ35W AND INTO NE
BRAZIL NEAR 2S47W. ISOLATED CLUSTERS OF MODERATE CONVECTION ARE
WITHIN 210 NM N AND 150 NM S OF THE AXIS W OF 13W. THE MOST
SIGNIFICANT OF THESE CLUSTERS IS NEAR 5N18W...OR ABOUT 375NM W
OF THE AFRICAN COAST.

...DISCUSSION...

THE GULF OF MEXICO...
A COLD FRONT HAS ENTERED THE NW GULF AND AS OF 01/2100 UTC
EXTENDS FROM THE LOUISIANA COAST NEAR 30N92W SW TO JUST OFFSHORE
MEXICO NEAR 23N97W. THE FRONT HAS BEEN FAIRLY EASY TO PLACE WITH
NW TO N WINDS 10-20 KT AND DEWPOINTS DROPPING INTO THE 50S
BEHIND THE FRONT...AND SLY WINDS GENERALLY 15-25 KT AND
DEWPOINTS IN THE 70S AHEAD OF THE FRONT. WIDESPREAD SEVERE
WEATHER OUTBREAK AHEAD OF THE FRONT IS STILL AFFECTING MUCH OF
THE SE U.S. A FEW CELLS ARE MOVING NE THROUGH THE FAR NRN
GULF...N OF 28N BETWEEN 86W-91W. VERY STRONG CLUSTER OF STORMS
SKIRTED THE GULF WATERS BETWEEN NEW ORLEANS AND MOBILE BETWEEN
20-22 UTC...WITH THE SLIDELL RADAR SHOWING SEVERAL THREE BODY
SCATTER SPIKES...THE CLASSIC SIGNAL OF LARGE HAIL. THE FRONT IS
ASSOCIATED WITH THE DEEP LAYER LOW SPINNING OVER IOWA. PRESENTLY
THOUGH...UPPER RIDGING EXTENDING INTO THE GULF FROM THE NE PAC
HAS WNW/NW FLOW OVER THE GOMEX. THIS IS ADVECTING A BAND OF
UPPER MOISTURE THROUGH THE GULF MAINLY N OF 23N. FRONT EXPECTED
TO MOVE TO A PSN BETWEEN NORTH CENTRAL FLORIDA AND THE BAY OF
CAMPECHE BY FRI NIGHT. SCATTERED SHOWERS AND TSTMS WILL MOVE E
WITH THE FRONT...MAINLY N OF 25N.

THE CARIBBEAN SEA...
THE MAIN STORY IN THE CARIBBEAN CONTINUES TO BE THE BRISK ELY
TRADES OVER MUCH OF THE AREA E OF 82W...AS SFC HIGH PRES N OF
THE AREA INTERACTS WITH LOWER PRESSURE NEAR COLOMBIA. THE TRADE
FLOW CONTINUES TO BE STRONGEST NEAR THE COLOMBIAN COAST WHERE
NEAR GALE CONDITIONS EXPECTED THROUGH FRI. THIS WILL ALSO
CONTINUE TO SEND MODERATE TO STRONG SURF TO THE CARIB COAST OF
NICARAGUA...COSTA RICA...AND PANAMA OVER THE NEXT FEW DAYS. SFC
WINDS BEND MORE SLY IN THE NW CARIB IN ADVANCE OF THE FRONTAL
SYSTEM MOVING INTO THE GULF. THE TRADES ARE ADVECTING TYPICAL
PATCHES OF LOW LEVEL MOISTURE WWD. HOWEVER...VERY LITTLE CLOUD
COVER IS SEEN OVER CARIB WATERS NEAR THE COLOMBIAN COAST WHERE
THE TRADES ARE STRONGEST...WHICH HAS LED TO A WELL MIXED LOWER
ATMOSPHERE. ALOFT...VERY DRY AND STABLE AIR DOMINATES YET AGAIN
WHICH HAS BEEN THE STORY FOR MUCH OF THE WINTER. THIS DRY AIR IS
ROTATING AROUND UPPER RIDGING CLIPPING THE FAR NW AND SE
PORTIONS...AND THE DOMINATING MID TO UPPER TROUGH EXTENDING SW
BETWEEN PUERTO RICO AND NRN COSTA RICA. THIS TROUGH HAS LED TO
AN UPPER CONFLUENT ZONE OFFSHORE NICARAGUA AND COSTA
RICA...WHERE THE DRIEST AIR IS SEEN.


THE ATLANTIC OCEAN...
FAIRLY AMPLIFIED UPPER RIDGE/TROUGH/RIDGE/TROUGH DOMINATES THE
DISCUSSION AREA. THE UPPER RIDGING BUILDING INTO THE WRN ATLC IS
SPREADING MOISTURE OVER THE CONVECTION IN THE SE U.S. OUT TO
70W. SHARP UPPER TROUGH AHEAD OF THIS IS ALONG 62W. UPPER
DIFFLUENT ZONE AHEAD OF THIS TROUGH IS HELPING TO SUPPORT THE
SCATTERED MODERATE CONVECTION SEEN FROM 25N-31N BETWEEN
55W-60W...AND ALSO N OF 28N BETWEEN 44W-51W. AT THE
SFC...RIDGING GENERALLY DOMINATES THE WRN AND ERN PORTIONS WITH
A 1022MB CENTER OFFSHORE HATTERAS NEAR 35N69W AND A 1026MB
CENTER W OF MADEIRA ISLAND NEAR 32N23W. LOW LEVEL CONFLUENT ZONE
BETWEEN THESE TWO HIGHS IS SUPPORTING THE COLD FRONT THAT ENTERS
THE AREA IN THE CENTRAL ATLC NEAR 32N44W AND CONTINUES SW TO
26N58W AND THEN IS A TROUGH THROUGH THE SE BAHAMAS NEAR 23N74W.
THIS FRONT WILL GRADUALLY BECOME DIFFUSE INTO THE
WEEKEND...WHILE THE HIGH OFFSHORE HATTERAS SLIDES E AHEAD OF THE
NEXT FRONT TO PUSH OFFSHORE INTO THE FAR NW PORTION OF THE
DISCUSSION AREA DURING FRI AND SAT.

$$
WILLIS




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