000
AXNT20 KNHC 032342
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI APR 03 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 6N10W 3N15W CROSSING THE EQUATOR 
NEAR 23W TO 4S40W. SCATTERED MODERATE CONVECTION IS WITHIN 180 
NM OF THE AXIS BETWEEN 12W-21W AND WITHIN 60 NM OF THE AXIS 
BETWEEN 27W-35W.   

...DISCUSSION...

THE GULF OF MEXICO...
A COLD FRONT IS SLOWING IN ITS FORWARD PROGRESSION FROM FORT 
MYERS FLORIDA TO THE N PORTION OF THE YUCATAN PENINSULA. THIS 
DECELERATION IS DUE THE ASSOCIATED RETREATING UPPER TROUGH OVER 
THE GREAT LAKES. SATELLITE IMAGERY AND DOPPLER RADAR REVEAL 
MULTILAYER CLOUDINESS AND SCATTERED SHOWERS WITHIN 90 NM OF THE 
FRONT. LIGHTNING DATA SUGGESTS LITTLE EMBEDDED TSTM ACTIVITY. 
NWP MODELS ARE IN AGREEMENT IN SHOWING THE FRONT STALL LATER 
TONIGHT AND THEN LIFT N AS A WEAKENING WARM FRONT SAT WITH 
DIMINISHING MOISTURE. A SPRAWLING MID-UPPER HIGH IS BUILDING 
BEHIND THE FRONT CENTERED JUST S OF MEXICO OVER THE GULF OF 
TEHUANTEPEC. THIS FEATURE IS EXPECTED TO DRIFT E THROUGH THE 
WEEKEND...DOMINATING THE WEATHER PATTERN OVER THE CENTRAL AND E 
PART. A STRONG COLD FRONT   

THE CARIBBEAN SEA...
WATER VAPOR IMAGERY AND SOUNDING DATA REVEAL ABUNDANT MID-UPPER 
LEVEL DRY AIR ACROSS THE REGION. THE ATMOSPHERE IS MOST STABLE 
IN AN UPPER CONFLUENT ZONE OVER THE SW CARIBBEAN BETWEEN A LARGE 
UPPER RIDGE OVER THE GULF OF TEHUANTEPEC AND TROUGHING OVER THE 
CENTRAL CARIBBEAN. IN THE LOWER LEVELS...THE ONLY NOTABLE AREA 
OF MOISTURE IS OVER THE LEEWARD ISLANDS ASSOCIATED WITH AN 
INVERTED TROUGH LOCATED JUST E OF THE ISLANDS ALONG 60W. SEVERAL 
OF THE SFC STATIONS HAVE BEEN REPORTING SHOWERS OVER THE PAST 
FEW HOURS AND THIS WILL LIKELY CONTINUE THROUGH TONIGHT AS THE 
WEAK BOUNDARY SLOWLY CROSSES THE ISLAND CHAIN. TRADES ARE 
GENERALLY E TO SE 15-20 KT...EXCEPT SLY 20-25 KT OVER THE NW 
CARIBBEAN IN RESPONSE TO A FRONT OVER THE SE GULF OF MEXICO. 
THIS FRONT IS NOT FORECAST TO ENTER THE CARIBBEAN.
 
THE ATLANTIC OCEAN...
A COUPLE OF FRONTS EXTENDING INTO THE SUBTROPICS ARE THE MAIN 
TALKING POINTS IN THE DISCUSSION ZONE. THE STRONGER FRONT IS 
OVER THE FAR NW PORTION FROM 31N77W TO CENTRAL FLORIDA. 
LOW-LEVEL CONVERGENCE ALONG THE BOUNDARY COUPLED WITH AN UPPER 
JET IS TRIGGERING SCATTERED SHOWERS AND TSTMS N OF 28N E OF THE 
FRONT TO 70W. SW WINDS ARE ON THE STRONG SIDE...20-25 KT... 
AHEAD OF THE FRONT BUILDING SEAS TO 10 FT AT BUOY 440O4 LOCATED 
NEAR 31N73W. THIS FRONT HAS SUFFICIENT SUPPORT TO CONTINUE SE 
FOR ANOTHER DAY OR TWO BEFORE STALLING. THE OTHER FRONT IS 
DISSIPATING AND STATIONARY OVER THE CENTRAL ATLC EXTENDING S 
FROM A 1014 MB LOW NEAR 31N42W TO 24N46W TO 21N52W. SCATTERED 
SHOWERS AND ISOLATED TSTMS LIE N OF 27N BETWEEN 32W-45W...MAINLY 
TIED TO A LARGER SCALE UPPER LOW. WEATHER CONDITIONS ARE FAIRLY 
TRANQUIL ELSEWHERE BENEATH MID-UPPER RIDGES. THE EXCEPTION IS 
S OF 7N BETWEEN 40W AND 60W WHERE AN UPPER DIFFLUENT PATTERN IS 
ENHANCING SCATTERED SHOWERS AND TSTMS...MAINLY INLAND OVER SOUTH 
AMERICA. 

$$
CANGIALOSI