[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261054
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN APR 26 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N8W 2N16W CROSSING THE EQUATOR NEAR
25W EXTENDING TO 1S30W 2S35W AND INTO NE BRAZIL NEAR 4S40W.
NUMEROUS MODERATE CONVECTION IS S OF 4N BETWEEN 3W-7W. SCATTERED
MODERATE CONVECTION IS S OF 5N BETWEEN 9W-14W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 1N-5N BETWEEN
14W-20W. SCATTERED MODERATE CONVECTION IS S OF 2N BETWEEN
41W-46W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH IS PRESENT ACROSS THE GULF REGION WITH THE
AXIS OF THIS TROUGH EXTENDING FROM 19N95W TO 24N88W TO N FLORIDA
NEAR 30N83W. TO THE W OF THIS TROUGH AXIS...UPPER LEVEL MOISTURE
IS BEING ADVECTED SOUTHEASTWARD ACROSS THE FAR W GULF...WHERE
HIGH LEVEL CLOUD COVERAGE IS INCREASING. ALSO...UPPER LEVEL
DIVERGENCE E OF THE UPPER LEVEL TROUGH AXIS IS SUPPORTING
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS S OF 25N BETWEEN
84W-88W. HOWEVER...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE
EXTENDING WESTWARD INTO THE SE CONUS FROM A 1031 MB SURFACE HIGH
OVER THE W ATLC NEAR 33N69W IS CURRENTLY RESULTING IN GENERALLY
FAIR WEATHER CONDITIONS ACROSS MUCH OF THE GULF REGION. THE FLOW
AROUND THE AFOREMENTIONED SURFACE RIDGE IS RESULTING IN E TO SE
WINDS OF 20 TO 25 KT ACROSS PORTIONS OF THE GULF...WITH E WINDS
UP TO 30 KT ACROSS THE STRAITS OF FLORIDA AND E TO SE WINDS UP
TO 30 KT OFF THE NW COAST OF YUCATAN. THE AFOREMENTIONED SURFACE
RIDGE IS FORECAST TO MAINTAIN FRESH TO STRONG E TO SE WINDS
ACROSS THE GULF THROUGH LATE MONDAY. THESE WINDS WILL CONTINUE
TO ADVECT LOW LEVEL MOISTURE ACROSS THE GULF REGION...WITH THE
ASSOCIATED INSTABILITY SUPPORTING THE AFOREMENTIONED SHOWER AND
THUNDERSTORM ACTIVITY.

CARIBBEAN SEA...
A 1031 MB SURFACE HIGH OVER THE W ATLC NEAR 33N69W IS
MAINTAINING FRESH TO STRONG TRADE WINDS ACROSS THE CARIBBEAN
SEA. THE STRONGEST WINDS ARE FOUND NEAR THE COAST OF COLOMBIA
AND THROUGH THE WINDWARD PASSAGE...WHERE NE TO E SURFACE WINDS
UP TO 30 KT ARE OCCURRING. A BROAD UPPER LEVEL RIDGE IS PRESENT
ACROSS THE CARIBBEAN SEA. ATMOSPHERIC STABILITY ASSOCIATED WITH
THIS RIDGE IS RESULTING IN GENERALLY FAIR WEATHER CONDITIONS
ACROSS MUCH OF THE CARIBBEAN. HOWEVER...THE TRADE WINDS ARE
ADVECTING POCKETS OF LOW LEVEL MOISTURE WITH ISOLATED SHOWERS
WESTWARD ACROSS THE CARIBBEAN. THE GREATEST CONCENTRATION OF
THESE SHOWERS IS FROM 12N-15N BETWEEN 62W-76W. ALSO...UPPER
LEVEL MOISTURE AND HIGH LEVEL CLOUDS CONTINUE TO STREAM
NORTHEASTWARD ACROSS THE W CARIBBEAN.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH OVER THE CENTRAL ATLC IS ASSOCIATED WITH A
SURFACE STATIONARY FRONT THAT EXTENDS FROM 25N60W TO 29N55W TO
32N52W TO NE OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE IS
SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN
120 NM EITHER SIDE OF THIS FRONT. THIS ACTIVITY IS ALSO BEING
SUPPORTED BY UPPER LEVEL DIVERGENCE IN THE NE QUADRANT OF AN
80-90 KT UPPER LEVEL WIND SPEED MAXIMUM LOCATED SW OF THE
SURFACE STATIONARY FRONT. TO THE W OF THE SURFACE STATIONARY
FRONT...DEEP LAYER DRY AIR AND SUBSIDENCE ASSOCIATED WITH A
1031 MB SURFACE HIGH NEAR 33N69W ARE RESULTING IN GENERALLY FAIR
WEATHER CONDITIONS. DURING THE NEXT DAY...THE SURFACE HIGH IS
FORECAST TO MOVE SOUTHWESTWARD AND BE LOCATED NEAR 32N72W AS A
1031 MB SURFACE HIGH AT 27/0600 UTC. FARTHER TO THE
E...SUBSIDENCE IN THE VICINITY OF A SURFACE RIDGE IS RESULTING
IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE CENTRAL
AND E ATLC. HOWEVER...ATMOSPHERIC INSTABILITY AND UPPER LEVEL
DIVERGENCE IN THE VICINITY OF AN UPPER LEVEL TROUGH WITH AN AXIS
EXTENDING FROM 25N29W TO 29N23W TO 32N18W TO NE OF THE
DISCUSSION AREA ARE RESULTING IN SCATTERED SHOWERS N OF 26N
BETWEEN 14W-23W. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL RIDGE
IS PRESENT WITH AN AXIS EXTENDING FROM 10N14W TO 6N27W TO 1N37W.
UPPER LEVEL DIVERGENCE IN THE VICINITY OF THIS UPPER LEVEL RIDGE
IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN




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