[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 031131
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN APR 03 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 1115 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE SRN COAST OF LIBERIA NEAR
5N9W ALONG 2N20W 1N30W CROSSING THE EQUATOR NEAR 37W AND INTO NE
BRAZIL TO NEAR 2S46W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 5N-6N BETWEEN 12W-16W. SIMILAR ACTIVITY IS
WITHIN 130 NM S OF THE AXIS BETWEEN 13W-16W...WITHIN 170 NM N OF
THE AXIS BETWEEN 20W-32W...AND FROM 1S-3N BETWEEN 45W-49W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF OF MEXICO REMAINS MOSTLY CLEAR UNDER THE INFLUENCE OF
SURFACE RIDGING AROUND A 1019 MB HIGH CENTERED S OF THE FLORIDA
PANHANDLE NEAR 28N85W. PATCHES OF LOW-LEVEL CLOUDS ARE ACROSS
THE WRN HALF OF THE BASIN WITH FOG OVER SE TEXAS INDICATED BY
SURFACE OBSERVATIONS AND SATELLITE DATA. A FEW ISOLATED
SHOWERS/THUNDERSTORMS ARE IN THE FAR SW GULF FROM 17N-23N
BETWEEN 95W-97W INDICATED BY LIGHTNING DATA. THESE STORMS ARE
ASSOCIATED WITH A DAMPENING SHORTWAVE UPPER TROUGH THAT EXTENDS
FROM 27N94W TO 23N97W. WEAK ANTI-CYCLONIC SURFACE FLOW IS AROUND
THE HIGH PRESSURE CENTER ACROSS THE NE GULF WITH MAINLY E-SE
WINDS OF 10-15 KT ACROSS THE REMAINDER OF THE BASIN.
ALOFT...NWLY WINDS ARE ACROSS THE NRN GULF AROUND THE ERN SIDE
OF AN APPROACHING UPPER RIDGE WITH SWLY WINDS ACROSS THE SRN
GULF AROUND ANOTHER UPPER LEVEL RIDGE CENTERED OVER THE ERN
CARIBBEAN. WATER VAPOR IMAGERY INDICATES STRONG DRY AIR IN THE
CONVERGENCE ZONE BETWEEN THE NWLY AND SWLY WINDS.  THE SWLY
WINDS ALOFT ARE ALSO DRAWING SOME E PACIFIC MOISTURE ACROSS THE
SRN GULF SUPPORTING HIGH CLOUDS. WITH THE LONGWAVE UPPER RIDGE
APPROACHING THE AREA...SURFACE RIDGING ALONG WITH MOSTLY FAIR
WEATHER WILL REMAIN DURING THE NEXT DAY OR SO BEFORE THE NEXT
UPPER TROUGH AND ASSOCIATED FRONTAL SYSTEM APPROACH THE AREA
LATE MONDAY. SE RETURN FLOW IS EXPECTED TO INCREASE AHEAD OF
THIS FRONT.

CARIBBEAN SEA...
THE CARIBBEAN ALSO REMAINS UNDER MOSTLY FAIR CONDITIONS UNDER
THE INFLUENCE OF AN UPPER LEVEL RIDGE CENTERED JUST N OF ERN
VENEZUELA NEAR 12N63W. MAINLY SWLY FLOW ALOFT COVERS THE WRN
HALF OF THE BASIN AROUND THIS UPPER RIDGE WHICH IS DRAWING UPPER
LEVEL MOISTURE FROM THE E PACIFIC ACROSS THIS PORTION OF THE
BASIN SUPPORTING HIGH CLOUDS. THE ERN HALF OF THE BASIN IS UNDER
THE INFLUENCE OF VERY DRY AIR WHICH IS SUPPORTING CLEAR SKIES.
FRESH ELY TRADEWINDS ARE ACROSS THE MAJORITY OF THE BASIN. TOTAL
PRECIPITABLE WATER IMAGERY SHOWS ENHANCED MOISTURE OVER THE NW
CARIBBEAN AND OFF THE COASTS OF PANAMA AND COSTA RICA. LIGHTNING
DATA INDICATES A LINE OF SHOWERS/THUNDERSTORMS JUST OFF THE
COAST OF COSTA RICA DUE TO THE COMBINATION OF ENHANCED MOISTURE
AND WIND CONVERGENCE ALONG THE COASTLINE. EXPECT LITTLE CHANGE
OVER THE NEXT 24 HRS.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH IS IMPACTING THE W ATLC WITH A LONGWAVE
UPPER TROUGH OFF THE ERN SEABOARD ALONG 70W SUPPORTING A COLD
FRONT WHICH ENTERS THE DISCUSSION AREA NEAR 32N53W CONTINUING SW
TO THE SE BAHAMAS NEAR 23N73W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 45 NM EITHER SIDE OF THE FRONT N OF
26N...WITH SCATTERED SHOWERS ALONG THE FRONT ELSEWHERE. A WEAK
1018 MB HIGH IS NOTED BEHIND THE FRONT NEAR THE NE BAHAMAS
PROVIDING FAIR CONDITIONS IN THE WAKE OF THE FRONT. FARTHER
E...A BROAD SURFACE RIDGE COVERS THE MAJORITY OF THE CENTRAL AND
ERN ATLC ANCHORED BY A [PAIR OF 1026 MB HIGHS NEAR 31N28W AND
29N37W WHICH IS PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE
AREA. ALOFT...AN UPPER LEVEL RIDGE EXTENDS NE FROM THE ERN
CARIBBEAN TO THE AZORES ISLANDS. THE FAR E ATLC IS COVERED BY AN
UPPER LEVEL TROUGH WITH AXIS EXTENDING W OF PORTUGAL ACROSS THE
MADEIRA ISLANDS WITH A PORTION THEN EXTENDING SW TO NRN SOUTH
AMERICA NEAR 7N53W. UPPER LEVEL MOISTURE IS BEING DRAWN NE
AROUND THE ERN SIDE OF THE TROUGH SUPPORTING HIGH CLOUDS NEAR
AND N OF THE WRN HALF OF THE ITCZ. THIS UPPER TROUGH ALSO
SUPPORTS A FRONTAL SYSTEM ACROSS SPAIN AND INTO NW AFRICA. BROAD
UPPER RIDGING COVERS THE TROPICAL ATLC S OF 17N E OF 43W. EXPECT
THE FRONTAL SYSTEM IN THE W ATLC TO CONTINUE TO MOVE EWD OVER
THE NEXT COUPLE OF DAYS.

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

$$
WALTON






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