[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 261049
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU MAR 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
1015 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N10W 1N20W...CROSSING THE EQUATOR
NEAR 21W...2S30W AND INTO NE BRAZIL NEAR 3S42W. SCATTERED
MODERATE CONVECTION IS N OF 3N TO INLAND OVER W AFRICA BETWEEN
4W-11W. ISOLATED MODERATE CONVECTION IS WITHIN 90 NM OF THE AXIS
BETWEEN 14W-20W. SCATTERED MODERATE CONVECTION IS S OF 2N
BETWEEN 38W-42W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0900 UTC...A COLD FRONT IS DRAPED ACROSS THE NW GULF
EXTENDING FROM A 1006 MB LOW LOCATED OVER SW MISSISSIPPI. THE
COLD FRONT ENTERS THE GULF NEAR VERMILION BAY WSW TO INLAND OVER
THE SE TEXAS COAST NEAR GALVESTON. A DOPPLER RADAR MOSAIC SHOWS
A STRONG LINE OF TSTMS ASSOCIATED WITH THIS BOUNDARY PROGRESSING
EWD EXTENDING FROM NRN ALABAMA THROUGH MOBILE BAY TO MORGAN CITY
LOUISIANA. HOWEVER...WHILE THESE STORMS ARE MOSTLY OVER THE SE
CONUS...SCATTERED SHOWERS AND TSTMS WILL REMAIN POSSIBLE ALONG
THE IMMEDIATE GULF COAST AS THE LINE MOVES EWD ACROSS THE
EXTREME NRN GULF WATERS N OF 28N. AHEAD OF THE FRONT...SOUTHERLY
RETURN FLOW OF 20-25 KT COVERS THE CENTRAL AND E GULF ON THE WRN
PERIPHERY OF A SURFACE RIDGE OVER THE W ATLC. ELSEWHERE...
SCATTERED CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE OVER THE ERN
GULF WHILE THE SE GULF AND BAY OF CAMPECHE REMAIN MOSTLY CLEAR
UNDER MODERATE SUBSIDENCE AND DRY AIR ALOFT.

CARIBBEAN SEA...
HIGH PRESSURE OVER THE W ATLC IS MAINTAINING FRESH TO STRONG
TRADE WINDS ACROSS THE CARIBBEAN. THE STRONGEST WINDS...20-25
KT...ARE OBSERVED ALONG THE COAST OF COLOMBIA. LOW-LEVEL WIND
SPEED CONVERGENCE IS GENERATING ISOLATED TRADE WIND SHOWERS
ACROSS THE ERN CARIBBEAN E OF 70W...WITH THE MOST CONCENTRATED
ACTIVITY IN THE NE CARIBBEAN. ALOFT...A TROUGH EXTENDS FROM THE
W ATLC ACROSS HISPANIOLA AND JAMAICA TO NICARAGUA...AND INTO
THE E PACIFIC. STRONG SUBSIDENCE AT THE BASE OF THIS TROUGH IS
CREATING A RELATIVELY STABLE ENVIRONMENT ACROSS THE CARIBBEAN NW
OF A LINE FROM PUERTO RICO TO PANAMA. 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
OCCLUDED SURFACE LOW CENTERED WELL NORTH OF THE AREA NEAR
40N57W. A PAIR OF SURFACE TROUGHS ARE SUPPORTED BY THE UPPER
LEVEL TROUGH...THE FIRST OF WHICH EXTENDS INTO THE DISCUSSION
AREA NEAR 32N45W THEN CONTINUES ALONG 30N46W 26N50W TO 18N54W.
SCATTERED SHOWERS ARE WITHIN 200 NM E OF THE TROUGH. WEST OF THE
INITIAL BOUNDARY...A SECONDARY SURFACE TROUGH ENTERS THE REGION
NEAR 31N51W AND CONTINUES ALONG 26N60W TO 28N71W. SCATTERED
SHOWERS EMBEDDED WITHIN BROKEN COLD-AIR STRATOCUMULUS CLOUDS ARE
WITHIN 120 NM EITHER SIDE OF THE TROUGH PRIMARILY E OF 75W. A
SECOND 1008 MB LOW PRESSURE SYSTEM IS SPINNING OVER THE E ATLC
NEAR 32N21W. A SURFACE TROUGH CURLS IN THE ERN SEMICIRCLE FROM
THE CIRCULATION CENTER ALONG 32N18W 29N19W...HOWEVER LITTLE
CONVECTION IS ASSOCIATED WITH THIS FEATURE DUE TO MID TO UPPER
LEVEL DRY AIR. BETWEEN THESE TWO LOW PRESSURE SYSTEMS...A NARROW
SURFACE RIDGE COVERS THE CENTRAL ATLC BETWEEN 27W-41W. IN THE
TROPICS...DIVERGENCE AROUND AN UPPER-LEVEL ANTICYCLONE NEAR
5N35W IS ENHANCING THE CONVECTION ALONG THE ITCZ.

$$
HUFFMAN


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