[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241741
TWDAT

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

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N9W 3N15W CROSSING THE EQUATOR NEAR
21W CONTINUING ALONG 1S30W AND INTO NE BRAZIL NEAR 3S40W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 220 NM
EITHER SIDE OF THE AXIS BETWEEN 11W-25W. ISOLATED MODERATE
CONVECTION IS S OF 2N W OF 40W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE HIGH PRESSURE IS CENTERED OVER THE W ATLC AND EXTENDS
RIDGING OVER THE NE WATERS PROVIDING LIGHT AND VARIABLE SURFACE
FLOW N OF 26N E OF 89W. HOWEVER...SE WINDS HAVE INCREASED TO
20-25 KT ACROSS THE REMAINDER OF THE GULF DUE TO THE TIGHT
PRESSURE GRADIENT BETWEEN THE W ATLC HIGH AND BROAD SURFACE
TROUGHING OVER N CENTRAL MEXICO. THIS STRONG FLOW IS ELEVATING
SEAS TO 8 FT OVER THE WRN WATERS AND WILL LIKELY INCREASE A FEW
MORE FT OVER THE NEXT DAY OR TWO AS WINDS REMAIN STRONG. DRY AIR
AND ZONAL FLOW IN THE MID AND UPPER LEVELS IS SUPPORTING THE
FAIR WEATHER OBSERVED ACROSS THE REGION THIS AFTERNOON. A
SHORTWAVE TROUGH CURRENTLY OVER CENTRAL TEXAS IS EXPECTED TO
TRACK EWD ALONG THE TEXAS/LOUISIANA COAST LATE TODAY AND SAT...
BRINGING AN INCREASE IN LOW AND MIDDLE LEVEL MOISTURE TO THE
NW PORTION OF THE GULF.

CARIBBEAN SEA...
ISOLATED WESTWARD MOVING SHOWERS LIE OVER A LARGE PORTION OF THE
CARIBBEAN AS LOW-LEVEL LIFT FROM TRADE WIND CONVERGENCE AND
MOIST ZONAL FLOW UNDER DIFFLUENCE ALOFT APPEAR TO BE THE PRIMARY
MECHANISMS. THE STRONG UPPER LEVEL SWLY FLOW ON THE NRN
PERIPHERY OF AN UPPER ANTICYCLONE CENTERED OVER VENEZUELA NEAR
5N66W IS SPREADING MOISTURE NE IN THE FORM OF MID-HIGH LEVEL
CLOUDINESS W OF 70W. TRADE WINDS ARE IN THE 25-30 KT RANGE NEAR
THE COAST OF COLOMBIA...AND MAINLY 20-25 KT ELSEWHERE. LITTLE
CHANGE IN THIS WIND REGIME IS EXPECTED THROUGH THE WEEKEND AS
STRONG HIGH PRESSURE REMAINS OVER THE W ATLC.

ATLANTIC OCEAN...
A LONGWAVE UPPER TROUGH CONTINUES TO PROVIDE SUPPORT FOR A COLD
FRONTAL BOUNDARY EXTENDING FROM 32N59W TO 29N62W THEN STATIONARY
SW TO THE WINDWARD PASSAGE. MULTILAYER CLOUDINESS WITH EMBEDDED
SCATTERED SHOWERS ARE WITHIN 300 NM E OF THE COLD FRONT AND
WITHIN 120 NM EITHER SIDE OF THE STATIONARY PORTION. A
REINFORCING FRONT IS APPROACHING THE AREA JUST SE OF BERMUDA.
THIS BOUNDARY WILL LIKELY MERGE WITH THE LEADING FRONT OVER THE
NEXT 24 HOURS AS MID-LEVEL ENERGY PUSHES SEWD AND BEGINS TO
FURTHER DISPLACE THE SURFACE FRONT TO THE EAST. A 1028 MB
SURFACE HIGH PRESSURE IS ESTABLISHED BEHIND THE FRONT NEAR
34N71W. THIS HIGH PRESSURE IS EXPECTED TO STRENGTHEN OVER THE
NEXT COUPLE OF DAYS IN THE W ATLC SETTING UP STRONG ELY FLOW ON
ITS SRN PERIPHERY. FARTHER E...A MID-UPPER LOW IS SITUATED NEAR
27N32W WITH TROUGHING EXTENDING WELL SW ALONG 14N45W 2N45W.
INSTABILITY ASSOCIATED WITH UPPER CYCLONE IS PRODUCING SCATTERED
SHOWERS FROM 23N-31N BETWEEN 25W-36W. AN UPPER JET ORIGINATES
NEAR THE BASE OF THE UPPER TROUGH AND EXTENDS NE FROM NORTH OF
THE CAPE VERDE ISLANDS TO NEAR THE CANARY ISLANDS. THIS FLOW IS
ADVECTING TROPICAL MOISTURE WELL NE INLAND ACROSS WESTERN SAHARA
AND MAURITANIA OVER W AFRICA.

$$
HUFFMAN


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