[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162320
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON APR 16 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
2215 UTC.

...THE ITCZ...
ITCZ AXIS EXTENDS FROM 8N11W 3N20W CROSSES THE EQUATOR AT 34W
AND CONTINUES INTO SOUTH AMERICA NEAR 3S45W. CLUSTERS OF
MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 60NM OF THE AXIS
BETWEEN THE AFRICAN COASTLINE AND 14W. ISOLATED MODERATE
CONVECTION IS WITHIN 60 NM S OF THE AXIS BETWEEN 19W-21W.

...DISCUSSION...

GULF OF MEXICO...
A 1024 MB HIGH OVER SE LOUISIANA IS KEEPING A COLDER AND DRIER
AIRMASS OVER THE GULF. A FAIRLY TIGHT PRES GRADIENT BETWEEN THIS
SFC HIGH AND A STRONG 971MB LOW OVER THE NORTHEAST U.S. IS
PRODUCING MODERATE TO STRONG NLY WINDS OVER THE E GULF AND THE
FLORIDA PENINSULA. BROKEN FAIR WEATHER STRATOCUMULUS CLOUDS
COVER THE W/CENTRAL GULF WHILE THE E GULF REMAINS MOSTLY CLEAR.
ALOFT...A RIDGE IS BUILDING OVER THE GULF WHILE A SHARP
SHORTWAVE TROUGH IS OVER THE SW US. THIS TROUGH WILL SUPPORT THE
NEXT COLD FRONT THAT IS FORECAST TO MOVE INTO THE GULF FROM THE
TEXAS COAST EARLY WED. A PLUME OF UPPER LEVEL MOISTURE
ASSOCIATED WITH THE EPAC JETSTREAM EXTENDS NEWD ACROSS N MEXICO
AND TEXAS. WINDS AND SEAS WILL SUBSIDE OVER THE GULF AS HIGH
PRES MOVES SLOWLY EWD.

CARIBBEAN SEA...
THE STRONG COLD FRONT THAT ENTERED THE NW CARIBBEAN YESTERDAY
HAS BECOME STATIONARY THROUGH MUCH OF THE CARIBBEAN. AS OF
21Z...THE COLD FRONT ENTERS THE FORECAST AREA NEAR 31N63W THEN
CONTINUES SW ACROSS THE CENTRAL BAHAMAS AND E CUBA BECOMING
STATIONARY NEAR 20N79W. A WELL DEFINED BAND OF LOW/MID CLOUDS
WITH POSSIBLE SHOWERS IS ASSOCIATED WITH THE FRONT. THE FRONT IS
FORECAST TO DISSIPATE IN THE NEXT 24-48 HOURS. WINDS BEHIND THE
FRONT REMAIN NLY AT 15-20 KT. THE REMAINDER OF THE BASIN
CONTINUES UNDER THE INFLUENCE OF A STRONG UPPER HIGH CENTERED
NEAR 14N71W WITH ABUNDANT DRY AND STABLE AIR ALOFT. THE TRADES
ARE LIGHT TO MODERATE ACROSS MUCH OF THE AREA DUE TO THE WEAK
PRES GRADIENT.

ATLANTIC OCEAN...
THE STRONG COLD FRONT ACROSS THE WESTERN ATLC IS PRODUCING GALE
FORCE WINDS AND HAZARDOUS MARINE CONDITIONS. AT 18Z SHIP
OBSERVATIONS REPORTED WINDS 25-30 KT AHEAD OF AND BEHIND THE
FRONT. A GALE WARNING IS IN EFFECT TONIGHT AND TUE IN THE SW N
ATLC N OF 27N. THIS COLD FRONT IS ASSOCIATED WITH A STRONG LOW
PRES SYSTEM THAT IS NOW CENTERED OVER LONG ISLAND. A DEEP
LAYERED TROUGH OVER THE FAR WEST ATLC IS SUPPORTING THIS FRONTAL
SYSTEM. THE MID/UPPER LEVEL RIDGE OVER THE CARIBBEAN EXTENDS NE
INTO THE W-CENTRAL ATLC THROUGH PUERTO RICO AND THE VIRGIN
ISLANDS. FARTHER E...AN UPPER TROUGH AND ASSOCIATED COLD FRONT
N OF THE AREA CONNECTS TO A SFC TROUGH NEAR 31N33W AND EXTENDS
TO 21N52W. A NARROW LINE OF LOW CLOUDS ARE ASSOCIATED WITH THIS
BOUNDARY. AN UPPER RIDGE DOMINATES THE E ATLC ANCHORED ON A 1021
MB HIGH LOCATED NEAR 30N27W. THIN HIGH CLOUDS EXTEND FROM N
SOUTH AMERICA ACROSS THE OCEAN ASSOCIATED WITH STRONG WLY WINDS.

$$
RJW




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