[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222331
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAR 22 2012

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
LIBERIA NEAR 6N10W TO 4N15W. THE ITCZ CONTINUES FROM 4N15W ALONG
3N25W 1N35W 2N41W TO THE BRAZIL COAST AT THE EQUATOR AND 47W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM S
OF THE AXIS BETWEEN THE AFRICAN COAST AND 15W. SIMILAR ACTIVITY
IS WITHIN 90-120 NM EITHER SIDE OF THE AXIS BETWEEN 18W AND 29W.

...DISCUSSION...

GULF OF MEXICO...
A STATIONARY FRONT CONTINUES TO SIT OVER THE CENTRAL/WRN GULF OF
MEXICO THIS AFTERNOON EXTENDING FROM THE MISSISSIPPI/ALABAMA
BORDER AT 30N89W TO A 1013 MB LOW NEAR 23N94W. A SURFACE TROUGH
EXTENDS S FROM THE LOW CENTER TO THE COAST OF MEXICO NEAR
19N92W. A LINE OF SLOW MOVING HEAVY SHOWERS/THUNDERSTORMS IS
ALONG THE FRONT N OF 29N EXTENDING NORTHWARD INTO THE COASTS OF
LOUISIANA...MISSISSIPPI AND ALABAMA. LIGHTNING DATA INDICATED
NUMEROUS STRIKES WITHIN THE PAST HOUR WITH THESE STORMS. THE
STORMS WERE CAPABLE OF PRODUCING VERY HEAVY RAINFALL WITH STORM
TOTAL AMOUNTS OF 8 TO 12 INCHES FORECAST FOR THE AREA. AN
ISOLATED CLUSTER OF STRONG THUNDERSTORMS WERE ALSO NOTED WITHIN
45 NM OF 26.5N88W WITH NUMEROUS LIGHTNING STRIKES AT PRESENT.
THE AREA OF LOW CLOUDS ASSOCIATED WITH THE REMAINDER OF THE
FRONT S OF 25N HAVE GRADUALLY DISSIPATED OVER THE PAST HOUR. THE
FRONT IS SUPPORTED BY A LARGE NEARLY STATIONARY CUT-OFF UPPER
LEVEL LOW OVER THE OKLAHOMA-KANSAS BORDER NEAR 37N98W. THE
ASSOCIATED TRAILING TROUGH WAS GRADUALLY FILLING AND LIFTING NWD
OVER THE NW GULF. A NARROW UPPER LEVEL RIDGE COVERS THE ERN GULF
WITH AXIS ALONG 82W. EXCEPT FOR THE MOISTURE NEAR THE FRONT N OF
29N...THE REMAINDER OF THE BASIN IS COVERED BY DRY AIR
ALOFT...WHICH IS HELPING MAINTAIN FAIR CONDITIONS AND CLEAR
SKIES ACROSS THE ERN GULF AND NW GULF. MAINLY SE-S FLOW IS
ACROSS THE BASIN BESIDES NEAR THE FRONT WITH SPEEDS OF 15-20 KTS
E OF THE FRONT...AND 10-15 KTS W OF THE FRONT. THE FRONT IS
EXPECTED TO LIFT NW AND DISSIPATE INTO A TROUGH AS SURFACE
RIDGING BUILDS WESTWARD ACROSS THE BASIN.

CARIBBEAN SEA...
MUCH OF THE CARIBBEAN IS EXPERIENCING FAIR WEATHER TODAY UNDER
THE INFLUENCE OF DRY AIR ALOFT IN MOSTLY SWLY FLOW ALOFT.
HOWEVER...AN AREA OF MOISTURE THAT LIKELY ADVECTED FROM THE
CENTRAL ATLC AFTER A FRONT DISSIPATED SEVERAL DAYS AGO IS
IMPACTING THE EXTREME NE CARIBBEAN PRODUCING SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS THE VIRGIN ISLANDS...PUERTO
RICO...AND HISPANIOLA N OF 18N BETWEEN 62-70W. SOME ISOLATED
SHOWERS ARE ALSO NOTED OVER THE FAR SE CORNER N OF VENEZUELA
AND THE ABC ISLANDS. THE REMAINDER OF THE BASIN HAS MOSTLY CLEAR
SKIES. TRADEWIND FLOW OF 15-20 KTS IS ACROSS THE MAJORITY OF THE
BASIN WITH SOME STRONGER WINDS NEAR THE COAST OF COLOMBIA.
EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS WITH CONTINUED
SHOWER ACTIVITY OVER THE NE ISLANDS AND N OF VENEZUELA.

ATLANTIC OCEAN...
SURFACE RIDGING COVERS THE W ATLC ANCHORED BY A 1030 MB HIGH
NEAR 34N68W PROVIDING MOSTLY FAIR WEATHER ACROSS THIS AREA. AN
AREA OF MOISTURE HAS ADVECTED AROUND THE SRN PORTION OF THE
RIDGE LIKELY ORIGINATED FROM A DISSIPATED FRONTAL BOUNDARY AND
IS NOW IMPACTING THE NE CARIBBEAN ISLANDS FROM 18N-21N BETWEEN
58W-73W. SCATTEROMETER DATA FROM A 1534 UTC OSCAT PASS SUPPORTED
THE PRESENCE OF A SHEAR LINE WHICH NOW EXTENDS FROM 20N50W TO
19N60W TO JUST NE OF HISPANIOLA. THE HIGH PRES AND ASSOCIATED
RIDGE IS SUPPORTED BY A HIGH AMPLITUDE UPPER LEVEL RIDGE
EXTENDING OFF THE ERN CONUS TO AN ANTICYCLONE NEAR 35N58W.
SHARP UPPER LEVEL TROUGH EXTENDS FROM 32N22W THROUGH 25N35W
THEN TRANSITIONS TO A SHEAR AXIS THROUGH 26N45W TO AN UPPER
LEVEL CYCLONE NEAR 26N64W. A REINFORCING UPPER LEVEL TROUGH
GRAZES THE DISCUSSION AREA ALONG 30N BETWEEN 30W AND 40W.
THE UPPER TROUGH SUPPORTS A COLD FRONT BRUSHING THE DISCUSSION
AREA NEAR 31N35W. THE FAR ERN ATLC IS COVERED BY AN UPPER LEVEL
RIDGE ALONG 9W. MAINLY WLY FLOW ALOFT COVERS THE TROPICAL ATLC.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
COBB






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