[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 252344
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAR 25 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
2230 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N11W 1N20W CROSSING THE EQUATOR
NEAR 34W AND INTO NE BRAZIL NEAR 2S45W. SCATTERED MODERATE
CONVECTION IS WITHIN 50 NM OF THE AXIS BETWEEN 15W-20W.
SCATTERED MODERATE TO STRONG CONVECTION IS FROM THE EQUATOR TO
5S BETWEEN 31W-37W.

...DISCUSSION...
GULF OF MEXICO...
SOUTHERLY RETURN FLOW OF 20-25 KT COVER THE MIDDLE AND EAST GULF
ON THE WESTERN PERIPHERY OF A SURFACE RIDGE OVER THE WEST ATLC.
A STATIONARY FRONT IS CURRENTLY POSITIONED ALONG THE LOUISIANA
AND UPPER TEXAS COASTLINES. SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH THIS BOUNDARY ARE MOSTLY OVER THE SE CONUS...HOWEVER...
ISOLATED THUNDERSTORMS MAY CLIP THE EXTREME NORTHERN WATERS THIS
EVENING. SCATTERED CLOUDS WITH ISOLATED SHOWERS ARE OVER THE
EASTERN GULF WHILE THE WESTERN GULF AND BAY OF CAMPECHE REMAIN
MOSTLY CLEAR UNDER MODERATE SUBSIDENCE AND DRY AIR ALOFT.

CARIBBEAN SEA...
HIGH PRESSURE OVER THE WEST ATLC IS MAINTAINING FRESH TO STRONG
TRADE WINDS ACROSS THE CARIBBEAN. THE STRONGEST WINDS...25-30
KT...ARE OBSERVED ALONG THE COAST OF COLOMBIA. LOW-LEVEL WIND
SPEED CONVERGENCE IS GENERATING ISOLATED TRADE WINDS SHOWERS
ACROSS THE CENTRAL AND EASTERN CARIBBEAN. ALOFT...A TROUGH
EXTENDS FROM THE W ATLC ACROSS HISPANIOLA...NICARAGUA...AND INTO
THE E PACIFIC. STRONG SUBSIDENCE AT THE BASE OF THIS TROUGH IS
CREATING A DRY AND STABLE ENVIRONMENT ACROSS THE CARIBBEAN NW OF
A LINE FROM THE MONA PASSAGE TO THE PANAMA/COSTA RICA BORDER.
E OF THE TROUGH AXIS...STRONG SWLY UPPER WINDS ARE TRANSPORTING
UPPER LEVEL MOISTURE AND MIDDLE TO HIGH CLOUDS ACROSS THE ERN
CARIBBEAN AND LESSER ANTILLES.

ATLANTIC OCEAN...
A DEEP-LAYERED LOW PRESSURE SYSTEM IS OVER THE W ATLC WITH THE
SFC LOW CENTERED WELL NORTH OF THE AREA NEAR 40N58W. A COLD
FRONT EXTENDS FROM THE LOW CENTER AND ENTERS THE DISCUSSION AREA
NEAR 31N52W THEN CONTINUES ALONG 25N60W 23N70W TO 24N75W WHERE
IT BECOMES STATIONARY TO 31N80W.SCATTERED SHOWERS ARE WITHIN 30
NM OF THE FRONTAL BOUNDARY. EAST OF THE FRONT...A SFC TROUGH
ENTERS THE REGION NEAR 31N47W AND CONTINUES ALONG 27N50W 20N54W
TO 16N57W. SCATTERED SHOWERS ARE WITHIN 200 NM OF THE TROUGH N
OF 19N. SCATTERED COLD-AIR STRATOCUMULUS CLOUDS HAVE FILLED IN
THE W ATLC BEHIND THE FRONT. A SECOND LOW PRESSURE SYSTEM IS
SPINNING OVER THE EAST ATLC NEAR 33N20W...HOWEVER LITTLE
CONVECTION IS ASSOCIATED WITH THIS FEATURE DUE TO MID TO UPPER
LEVEL DRY AIR. BETWEEN THESE TWO LOW PRESSURE SYSTEMS...A NARROW
SFC RIDGE COVERS THE CENTRAL ATLC BETWEEN 27W-44W. IN THE
TROPICS...DIVERGENCE AROUND AN UPPER-LEVEL ANTICYCLONE NEAR
4N35W IS ENHANCING CONVECTION ALONG THE ITCZ.

$$
RJW



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