000
AXNT20 KNHC 241759
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE FEB 24 2009

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 ITCZ AXIS WAS CENTERED ALONG 4.5N 07W TO 3N16W CROSSING THE 
EQUATOR NEAR 22W TO 1S24W EXTENDING WWD ALONG 1S INTO NE BRAZIL 
NEAR 2S45W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION WAS 
OCCURRING 90 NM EITHER SIDE OF AXIS FROM AFRICA W TO 25W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION WAS ALSO OCCURRING 
WITHIN 120 NM OF AXIS FROM 34W TO THE MOUTH OF THE AMAZON AT 48W 
AND CONTINUED NW WITHIN 90 NM OF THE COAST TO 5N 52W. 

...DISCUSSION...

GULF OF MEXICO...
A HIGH PRESSURE RIDGE ALOFT CONTINUES TO BUILD ACROSS THE W AND 
NW GULF FROM THE EPAC...TO THE W AND NW OF A W ATLC TROUGH THAT 
BECOMES A SHARP NARROW TUTT FROM THE CENTRAL BAHAMAS W TO THE 
YUCATAN CHANNEL THEN CONTINUES SW ACROSS THE PENINSULA AND SRN 
MEXICO INTO THE EPAC. THIS WAS HELPING TO CREATE A FAIR WEATHER 
PATTERN ACROSS THE GULF REGION...DUE TO SUBSIDENT STABLE 
ATMOSPHERIC CONDITIONS...AND DEEP LAYER DRY AIR. HOWEVER...UPPER 
LEVEL MOISTURE WAS STREAMING SOUTHEASTWARD ACROSS EXTREME NE 
PORTIONS OF THE GULF BUT YIELDING ONLY HIGH CLOUDS. A BROAD 1035 
MB HIGH DOMINATED MOST OF THE ERN SEABOARD...WITH A MODERATE NE 
TO E LOW LEVEL WIND FLOW OVER THE E HALF OF THE GULF AND BAY OF 
CAMPECHE...AND WEAKENED SE TO S WINDS DOMINATING THE NW GULF. 
WINDS AND SEAS HAVE FALLEN CONSIDERABLY SINCE YESTERDAY...IN THE 
WAKE OF A DIFFUSE COLD FRONT OVER THE SW NORTH ATLC AND NW 
CARIBBEAN. STRONG N TO NE SURFACE WINDS CONTINUE TO FUNNEL 
THROUGH THE ISTHMUS OF TEHUANTEPEC... RESULTING IN GALE FORCE 
WINDS IN THE E PACIFIC REGION. THESE WINDS HAVE GRADUALLY 
DIMINISHED DURING THE PAST 24 HOURS AND ARE EXPECTED TO FALL 
BELOW GALE FORCE WITHIN 12 HOURS. 

CARIBBEAN SEA...
A LARGE UPPER RIDGE CENTERED OVER NE VENEZUELA DOMINATES MOST OF 
THE CARIBBEAN ALOFT. THE W ATLC UPPER TROUGH AND ATTENDANT TUTT 
STRETCHED E TO W ACROSS THE EXTREME NW CARIBBEAN...WITH A 65-90 
KT JET SEGMENT EXTENDING FROM CENTRAL AMERICA ENE ALONG AND JUST 
S OF 20N TO 70W...BEFORE DIVERTING INTO TWO BRANCHES ACROSS AND 
N OF PUERTO RICO. THIS BROAD ZONE OF STRONG WLY WINDS ALOFT WAS 
AIDING IN ENHANCING CONVECTION ACROSS THE CARIBBEAN AND S HALF 
OF THE BAHAMAS W OF 70W. BROAD MOISTURE CONVERGENCE ASSOCIATED 
WITH THE DIFFUSE FRONTAL REMNANTS WAS YIELDING CLUSTERS OF 
BROKEN LOW TO MID LEVEL CLOUDS AND SCATTERED SHOWERS STREAMING 
SW 20-30 KT ACROSS THE NW AND W CARIB FROM ERN CUBA TO NRN 
NICARAGUA... WITH UPPER SPEED DIVERGENCE ENHANCING ISOLATED 
EMBEDDED TSTMS. ANOTHER SIGNIFICANT CLUSTER OF BROKEN CLOUDS AND 
SHOWERS WAS CENTERED ACROSS THE CENTRAL CARIBBEAN HALFWAY 
BETWEEN HAITI AND COLOMBIA WHERE THE UPPER JET WAS ALSO 
ENHANCING ISOLATED TSTMS. E OF 70W....SHALLOW LLVL MOISTURE 
TRAPPED BELOW A STRONG TEMPERATURE INVERSION AT AROUND 7K FT WAS 
EMBEDDED IN THE FRESH ELY FLOW...AND YIELDING SCATTERED PASSING 
SHOWERS...MAINLY S OF 16N.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH WAS SWEEPING ACROSS THE W ATLC AND NW 
BAHAMAS...AND IS ASSOCIATED WITH A SURFACE COLD FRONT THAT 
EXTENDS FROM THE CENTRAL ATLC SW TO 30N61W THROUGH THE S CENTRAL 
BAHAMAS NEAR LONG ISLAND THEN WSW THROUGH CENTRAL CUBA WHERE IT 
HAS BECOME DIFFUSE INTO THE NW CARIB. LOW LEVEL CONVERGENCE IS 
SUPPORTING SCATTERED SHOWERS WITHIN 90 NM NW AND 60 NM SE OF 
THIS FRONT. E OF THE FRONT SUBSIDENCE ASSOCIATED WITH DEEP 
LAYERED HIGH PRESSURE WAS SUPPORTING FAIR WEATHER...WITH FRESH E 
TO NE TRADE WINDS S OF 22N. TO THE NE...A DEEP LAYERED LOW HAD A 
1009 MB SURFACE REFLECTION NEAR 33N28W...SINKING SWD...AND 
SUPPORTING A COLD FRONT SPIRALING S THEN WSW FROM THE LOW. A  
COMPLEX 1010 MB SURFACE LOW EXTENDING FROM THE CANARY ISLANDS N 
FOR A FEW DEGREES WAS SUPPORTING A SURFACE TROUGH S INTO NW 
AFRICA. ANOTHER WEAK 1007 MB LOW WAS NOTED ALONG THE W AFRICA 
COAST NEAR 10.5N 16W...AND WAS PART OF THE SEMI PERMANENT LOW 
PRESSURE TROUGH EXTENDING W TO E ACROSS TROPICAL AFRICA. A LARGE 
PLUME OF SHALLOW SAHARAN AIR HAS EXITED W AFRICA IN THE PAST 36 
HOURS AND COVERED THE FAR ERN TROPICAL ATLC S OF THE CAPE VERDES 
TO JUST N OF THE ITCZ AND W TO NEAR 30W. UPPER LEVEL RIDGING 
ACROSS THE EQUATORIAL ATLANTIC WAS GENERALLY PRODUCING DIVERGENT 
CONDITIONS ALOFT AND HELPING TO MAINTAIN AN ACTIVE ITCZ...FOR 
FEBRUARY. 

$$
STRIPLING