[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 230524
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU APR 23 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N8W 2N16W CROSSING THE EQUATOR NEAR
21W TO 1S35W TO NE BRAZIL NEAR 3S42W. SCATTERED MODERATE
CONVECTION IS FROM 2N-5N BETWEEN 15W-31W.

...DISCUSSION...
GULF OF MEXICO...
SFC HIGH PRESSURE IS SHIFTING E CENTERED OVER THE NE WATERS NEAR
27N85W. WINDS ARE LIGHT AND VARIABLE ACROSS MUCH OF THE
AREA...BUT SLY WINDS ARE INCREASING OVER THE FAR NW WATERS IN
RESPONSE TO LOW PRESSURE OVER THE S CENTRAL PLAINS. E TO SE
WINDS ARE EXPECTED TO INCREASE TO 20-25 KT OVER MUCH OF THE AREA
TONIGHT AND FRI AS HIGH PRESSURE STRENGTHENS OFF THE SE CONUS
COAST. DRY AIR IN THE MID AND UPPER LEVELS IS SUPPORTING FAIR
WEATHER ACROSS THE ENTIRE REGION.  MAINLY FAIR WEATHER IS
EXPECTED TO CONTINUE OVER THE NEXT COUPLE OF DAYS...THOUGH
ISOLATED SHOWERS WILL LIKELY DEVELOP IN THE STRONG LOW-LEVEL
FLOW.

THE CARIBBEAN SEA...
SCATTERED MODERATE TO STRONG CONVECTION IS LOCATED OVER THE
EXTREME SW CARIBBEAN S OF 11N W OF 74W. LOW-LEVEL LIFT FROM
CONVERGENCE ALONG THE ITCZ AND UPPER DIFFLUENCE APPEAR TO BE THE
PRIMARY FACTORS FUELING THE CONVECTION. HOWEVER...LOCAL AND
SMALL SCALE EFFECTS OVER COLOMBIA ARE PROVIDING ENHANCEMENT FOR
THE DEEPER ACTIVITY NOTED INLAND. SWLY FLOW ALOFT IS SPREADING
SOME MOISTURE NE THOUGH IT APPEARS TO BE ONLY IN THE FORM OF
MID-HIGH LEVEL CLOUDINESS. MORE DENSE LOW-LEVEL CLOUDS ARE
EVIDENT OVER HISPANIOLA ASSOCIATED WITH A WEAK LOW-LEVEL TROUGH
AND LIKELY ENHANCED BY UPSLOPE FLOW. TRADE WINDS ARE IN THE
20-25 KT RANGE OVER THE S CARIBBEAN AND MAINLY 15-20 KT
ELSEWHERE. WINDS ARE EXPECTED TO INCREASE OVER THE WRN HALF OF
THE REGION AS HIGH PRESSURE STRENGTHENS OVER THE W ATLC.

THE ATLANTIC OCEAN...
SCATTERED SHOWERS AND TSTMS ARE WITHIN 300 NM E OF A COLD FRONT
EXTENDING FROM 32N67W TO THE WINDWARD PASSAGE. THIS ACTIVITY
IS BEING ENHANCED BY STRONG SWLY UPPER FLOW AND A DIFFLUENT
PATTERN BETWEEN THE ASSOCIATED TROUGH OVER THE NE CONUS AND A
RIDGE OVER THE CENTRAL ATLC. A REINFORCING FRONT EXTENDS FROM
32N70W TO 29N72W WITH INCREASING WLY WINDS BEHIND IT.
OVER THE CENTRAL ATLC...DEEP LAYER TROUGHING REMAINS WELL
DEFINED PROVIDING SOME SUPPORT FOR A STATIONARY FRONT EXTENDING
FROM 32N34W TO 27N50W AND A WEAK TROUGH ALONG 35W N OF 26N. THE
COMBINATION OF LOW-LEVEL CONVERGENCE AND INSTABILITY ALONG THE
UPPER TROUGH AXIS IS PRODUCING SCATTERED SHOWERS AND TSTMS FROM
29N-32N BETWEEN 35W-38W. THE TIGHT PRESSURE GRADIENT BETWEEN THE
FRONT AND HIGH PRES TO ITS N IS CAUSING STRONG NE 20-30 KT FLOW
WITH HIGHER GUSTS N OF THE FRONT. AN UPPER JET EXTENDING NE FROM
9N41W TO THE CAPE VERDE ISLANDS IS ADVECTING SOME MOISTURE
WITHIN 240 NM E OF THE JET AXIS.

$$
CANGIALOSI





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