[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU FEB 17 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND 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.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM THE S
CENTRAL COAST OF NIGERIA NEAR 05N05W TO 04N17W TO 00N26W TO
02N36W TO THE COAST OF BRAZIL NEAR 00N48W. SCATTERED MODERATE
AND ISOLATED STRONG CONVECTION IS NOTED WITHIN WITHIN 75 NM OF
THE AXIS BETWEEN 10W AND 20W AND ALSO WITHIN 120 NM OF THE AXIS
BETWEEN 20W AND 29W. SIMILAR CONVECTION IS NOTED WITHIN 90 NM N
OF THE AXIS W OF 44W.

...DISCUSSION...

GULF OF MEXICO...
BROAD RIDGING ALOFT EXTENDS FROM CENTRAL MEXICO NE ACROSS E
TEXAS AND INTO THE MID MISSISSIPPI VALLEY WITH VERY DRY AIR
ACROSS THE GULF UNDER STRONG SUBSIDENCE. A SURFACE RIDGE EXTENDS
FROM 1030 MB HIGH PRES IN THE W ATLANTIC TO ACROSS THE NORTHERN
GULF COAST TO THE NE COAST OF MEXICO NEAR 24N98W WITH SOUTHERLY
RETURN FLOW EVIDENT ACROSS THE MAJORITY OF THE GULF WATERS. THIS
RETURN FLOW IS BANKING LOW LEVEL CLOUDS AND PATCHY FOG OVER THE
FAR W GULF TO INLAND TEXAS. THE SURFACE RIDGE WILL REMAIN IN
PLACE ACROSS THE N GULF THROUGH SUN.

CARIBBEAN SEA...
AN UPPER RIDGE EXTENDS FROM NEAR THE COLOMBIA AND PANAMA BORDER
NW ACROSS CENTRAL AMERICA TO CENTRAL GUATEMALA RESULTING IN SW
TO W FLOW ALOFT OVER THE CARIBBEAN. REMNANT SURFACE MOISTURE IN
THE FORM OF SCATTERED SHOWERS AND ISOLATED TSTMS FROM A DECAYED
FRONT REMAINS OVER THE NW CARIBBEAN EXTENDING FROM HAITI TO
ACROSS JAMAICA TO THE NE COAST OF HONDURAS. FAIR WEATHER EXISTS
ACROSS THE REMAINDER OF THE BASIN EXCEPT FOR ISOLATED SHOWERS
WHICH ARE OVER THE NE AND N CENTRAL WATERS BEING USHERED IN FROM
THE TROPICAL N ATLC BY EASTERLY TRADE WINDS. WEAK LOW PRES JUST
W OF THE COAST OF COLOMBIA AND N OF THE ISTHMUS OF PANAMA WILL
REMAIN NEARLY STATIONARY THROUGH SUN. TRADE WINDS WILL INCREASE
LATE SUN AS HIGH PRES BUILDS DOWN FROM N OF CUBA AND HISPANIOLA.

ATLANTIC OCEAN...
IN THE FAR E ATLANTIC...AN UPPER RIDGE EXTENDS FROM AN
ANTICYCLONE S OF THE EQUATOR THROUGH 00N18W TO 13N25W. A MID TO
UPPER LEVEL TROUGH IS OVER W AFRICA NE OF THE RIDGE AXIS.
CONVECTION IS BEING ENHANCED BETWEEN THE TWO WITH SCATTERED
MODERATE TO STRONG CONVECTION FROM 00N TO 02N BETWEEN 04W AND
14W. IN THE W ATLANTIC...A WEAK COASTAL TROUGH IS BEGINNING TO
FORM JUST E OF THE N FLORIDA COAST OVER THE GULF STREAM
GENERATING SCATTERED SHOWERS WITH DENSE FOG OVER THE
JACKSONVILLE COASTAL WATERS UNDER MOIST ONSHORE FLOW. 1030 MB
HIGH PRES IS JUST N OF THE AREA NEAR 33N66W. A SURFACE RIDGE
EXTENDS SE FROM THE HIGH TO NEAR 27N47W. A COLD FRONT IS E OF
THE RIDGE EXTENDING FROM 32N34W THROUGH 24N50W TO 23N57W. A
FRONTAL TROUGH EXTENDS FROM THERE TO NEAR 21N67W. SCATTERED
SHOWERS AND ISOLATED TSTMS ARE LAGGING WITHIN 180 NM BEHIND THE
FRONT. RECENT ASCAT AND WINDSAT SCATTEROMETER PASSES INDICATED
NORTHERLY WINDS OF 20 TO 25 KT BEHIND THE FRONT. THIS FRONT WILL
SLOWLY DISSIPATE AS IT PUSHES E THROUGH SUN. THE HIGH AND RIDGE
WILL WEAKEN AS A REINFORCING COLD FRONT ENTERS THE AREA SAT
AFTERNOON THROUGH SUN WITH INCREASING NORTHERLY WINDS BEHIND THE
FRONT AND INCREASING SW WINDS AHEAD OF THE FRONT AND SEAS
BUILDING TO NEAR 26 FT N OF 31N. HIGH PRES BUILDS BACK IN FROM
THE CAROLINAS BEHIND THE REINFORCING FRONT BY LATE SUN WITH
SOUTHERLY RETURN FLOW SETTING UP OFF THE N FLORIDA COAST.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
LEWITSKY



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