000
AXNT20 KNHC 011746
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI MAY 01 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.

...THE ITCZ...

THE ITCZ AXIS EXTENDS FROM W AFRICA AT 6N11W ALONG 4N20W TO THE 
EQUATOR AT 25W THEN CONTINUING ALONG 2S30W AND INTO NE BRAZIL 
NEAR 3S43W. SCATTERED MODERATE CONVECTION IS NOTED S OF 5N E OF 
17W. 

...DISCUSSION...

GULF OF MEXICO...
A RIDGE OF HIGH PRESSURE EXTENDS FROM THE W ATLC ACROSS THE NRN 
GULF. LOW PRESSURE REMAINS IN PLACE OVER THE MEXICAN PLATEAU AND 
THE RESULTING PRESSURE GRADIENT BETWEEN THESE FEATURES IS 
SUPPORTING 15 TO 20 KT E TO SE FLOW FROM THE STRAITS OF FLORIDA 
TO THE TEXAS COAST. BUOY OBSERVATIONS AND AN EARLIER QSCAT PASS 
THIS MORNING CONFIRMS THESE WINDS SPEEDS WITH GENERALLY FAIR 
WEATHER CONDITIONS ACROSS THE BASIN. ALOFT...AN UPPER LEVEL 
TROUGH IS ACROSS THE WRN GULF AND DIPS SOUTHWARD ACROSS SRN 
MEXICO INTO THE E PACIFIC REGION. S-SW UPPER FLOW CONTINUES TO 
ADVECT UPPER LEVEL MOISTURE IN THE FORM OF HIGH CIRRUS CLOUDS 
ACROSS THE SRN GULF. LITTLE CHANGE IS EXPECTED THROUGH EARLY 
SATURDAY WHEN SLY WINDS INCREASE ACROSS THE WRN GULF AHEAD OF 
THE NEXT COLD FRONT POISED TO ENTER THE NW WATERS LATE SUNDAY.

CARIBBEAN SEA...
A 1033 MB SURFACE HIGH CENTERED WELL NORTH OF THE AREA OVER THE 
NW ATLC IS MAINTAINING GENERALLY MODERATE E-NE TRADES WINDS 
ACROSS THE CARIBBEAN...ALTHOUGH SOMEWHAT HIGHER ACROSS PORTIONS 
OF THE CENTRAL CARIBBEAN AND ALSO ALONG THE COAST OF NRN 
COLOMBIA. LOW-LEVEL SURFACE WIND CONVERGENCE IS KEEPING 
SCATTERED SHOWERS EMBEDDED WITHIN THE TRADE WIND FLOW MAINLY 
OVER THE NW CARIBBEAN AND INLAND OVER THE HIGHER TERRAIN OF 
NICARAGUA AND HONDURAS. ALSO...THE SWRN EXTENT OF A SURFACE 
TROUGH ACROSS THE CENTRAL ATLC IS PROVIDING WEAK SURFACE 
CYCLONIC FLOW ACROSS THE LESSER ANTILLES AND IS GENERATING 
SCATTERED SHOWERS N OF 13N ACROSS THE FAR ERN CARIBBEAN.
   
ATLANTIC OCEAN...
W OF 50W...AN UPPER LEVEL TROUGH AXIS EXTENDS FROM 32N54W TO ERN 
HISPANIOLA. DIFLUENT FLOW ALOFT ON THE SE SIDE OF THE UPPER 
TROUGH IS SUPPORTING AN ELONGATED SURFACE TROUGH FROM 28N55W TO 
18N59W. SATELLITE IMAGERY SHOWS COPIOUS CLOUD COVER AND LIKELY 
WIDESPREAD SHOWER ACTIVITY WITHIN 200 NM EITHER SIDE OF THE 
SURFACE TROUGH. A 1033 MB SURFACE HIGH IS CENTERED WELL NE OF 
BERMUDA AND EXTENDS A SURFACE RIDGE SW THROUGH BERMUDA TO ACROSS 
THE CENTRAL FLORIDA PENINSULA. BUOYS AND SCATTEROMETER DATA SHOW 
A BAND OF NE TRADES AROUND 15 KT WITHIN ONLY A FEW PATCHES OF 20 
KT...MAINLY S OF 26N BETWEEN THE RIDGE AND THE SURFACE TROUGH 
ACROSS THE W ATLC. SCATTERED SHOWERS EMBEDDED IN THIS FLOW 
DIMINISH AS THEY MOVE WEST AWAY FROM THE MOIST TROUGH AND INTO 
DRIER AND MORE STABLE AIR NEAR THE BAHAMAS. E OF 50W...A SURFACE 
RIDGE EXTENDS FROM A 1030 MB HIGH PRESSURE CELL OFF THE IBERIAN 
PENINSULA THROUGH THE AZORES TO A 1026 MB HIGH NEAR 30N48W. THIS 
RIDGE HAS BEEN WEAKENING AND SHIFTING EAST AHEAD OF A BROAD 
UPPER TROUGH DIGGING THROUGH THE CENTRAL ATLC. PERSISTENT 20 TO 
25 NE WINDS ARE OBSERVED OFF THE NW AFRICAN COAST THROUGH THE 
CANARY ISLANDS BETWEEN THE SURFACE RIDGE AND LOW PRESSURE OVER W 
AFRICA. GENERALLY 15 TO 20 KT TRADES PERSIST ELSEWHERE S OF 25N 
ON THE SRN PERIPHERY OF THE RIDGE. GENERALLY A DRY STABLE 
AIRMASS REMAINS IN PLACE WITH THE ONLY NOTABLE CONVECTION WELL 
TO THE SOUTH ALONG THE ITCZ OFF THE COAST OF LIBERIA.

$$
HUFFMAN