[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122345
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE FEB 12 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 6N11W 3N20W 2N30W 2N40W EQ48W
INTO NE BRAZIL. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION
IS WITHIN 120-130 NM N OF AXIS BETWEEN 23W-38W...AND WITHIN
100-120 NM S OF AXIS BETWEEN 30W-34W. SIMILAR CONVECTION IS FROM
5N-7N BETWEEN 16W-20W.

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 21Z...A COLD FRONT HAS ENTERED THE NW CORNER OF THE GULF.
THE MOSAIC DOPPLER RADAR FROM THE SE U.S. SHOWS A STRONG BAND OF
SHOWERS AND TSTMS ASSOCIATED WITH THIS FRONT. THE STRONGEST
TSTMS ARE MOVING ACROSS SE LOUISIANA AND THE N GULF WATERS N OF
28N BETWEEN 90W-95W. A LONG WAVE TROUGH EXTENDING FROM JUST WEST
OF THE GREAT LAKES SWWD TO CENTRAL TEXAS AND NE MEXICO SUPPORTS
THIS FRONTAL ZONE. A STRONG SHORT WAVE TROUGH IS MOVING EWD
AROUND THE BASE OF THIS TROUGH...AND ACROSS THE E-CENTRAL GULF.
THIS FEATURE IS GENERATING A BROAD AREA OF SHOWERS WITH EMBEDDED
TSTMS THAT IS AFFECTING THE E PORTION OF THE GULF AND THE STATE
OF FLORIDA. AS A RESULT...A TORNADO WATCH HAS BEEN ISSUED FOR
ALL OF SOUTH FLORIDA UNTIL 11 PM EST. LIGHTNING DATA REVEALS
SCATTERED TSTMS OVER THE SE PORTION OF THE GULF AND NEAR 27N86W.
A WARM FRONT IS ALSO ANALYZED ACROSS CENTRAL FLORIDA JUST N OF
LAKE OKEECHOBEE. THIS FRONT IS SPREADING ALL THIS SHOWER/TSTM
ACTIVITY NORTH. SLY SURFACE FLOW DOMINATES THE GULF AHEAD OF THE
COLD FRONT WHILE MODERATE TO STRONG NLY WINDS ARE FOUND BEHIND
THE FRONTAL BOUNDARY...WHICH IS FORECAST TO MOVE SE ACROSS THE
AREA REACHING FROM THE FLORIDA PANHANDLE TO BAY OF CAMPECHE WED
MORNING.

THE CARIBBEAN SEA...
THE SHORT WAVE TROUGH OVER THE E-CENTRAL GULF OF MEXICO DIGS
INTO THE YUCATAN CHANNEL AND NW PORTION OF THE CARIBBEAN SEA.
DIFFLUENCE AHEAD OF THIS TROUGH IS HELPING TO INDUCE SOME SHOWER
ACTIVITY OVER WESTERN CUBA. THE REMAINDER OF THE BASIN IS UNDER
THE INFLUENCE OF A BROAD RIDGE ANCHORED ON A HIGH OVER N SOUTH
AMERICA. SWLY UPPER LEVEL FLOW ON THE WESTERN SIDE OF THIS RIDGE
IS ADVECTING UPPER LEVEL MOISTURE FROM THE EPAC INTO THE SW
CARIBBEAN THROUGH COSTA RICA...PANAMA AND N COLOMBIA. PRES
GRADIENT BETWEEN A SFC HIGH N OF AREA AND THE COLOMBIAN LOW IS
PRODUCING MODERATE TRADEWINDS...PARTICULARLY OVER THE E AND
CENTRAL CARIBBEAN WITH THE STRONGEST WINDS AS USUAL ALONG THE
COAST OF N COLOMBIA. SMALL PATCHES OF LOW LEVEL CLOUDS DOTS THE
BASIN. SOME OF THEM ARE MOVING WWD BETWEEN THE N LEEWARD ISLANDS
AND HISPANIOLA.

THE ATLANTIC OCEAN...
A COLD FRONT ENTERS THE AREA NEAR 31N48W THEN CONTINUES SW TO
25N70W. AT THIS POINT...A WARM FRONT EXTENDS WWD TO CENTRAL
FLORIDA AND THE EASTERN GULF OF MEXICO NEAR 27N86W. A 80 NM WIDE
BAND OF BROKEN TO OVERCAST LOW/MID CLOUDS IS RELATED TO THE
FRONT. A DIFFERENCE IN PRES BETWEEN A 1031 MB HIGH LOCATED
MIDWAY BETWEEN CAPE HATTERAS AND BERMUDAS AND LOWER PRES OVER
THE SE U.S WILL PRODUCE GALE FORCE WINDS ACROSS THE SW N ATLC
JUST E OF N FLORIDA AND WEST OF 70W TONIGHT. A GALE WARNING IS
ALREADY IN EFFECT. A RIDGE/TROUGH/RIDGE/TROUGH PATTERN DOMINATES
THE FORECAST AREA WITH A STRONG UPPER LEVEL TROUGH OVER THE E
ATLC. THIS TROUGH EXTENDS FROM A VIGOROUS CUT-OFF LOW LOCATED N
OF THE MADEIRA ISLANDS SWWD REACHING THE CAPE VERDE ISLANDS. A
SHORT WAVE TROUGH IS E OF THE LESSER ANTILLES ALONG 54W/55W. AN
AREA OF MAINLY LOW CLOUDS AND ISOLATED SHOWERS IS OBSERVED AHEAD
OF THE TROUGH AXIS.

$$
GR





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