[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN APR 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 AT 6N11W TO 4N14W. THE ITCZ CONTINUES FROM 4N14W ALONG
3N30W 1N43W TO THE COAST OF BRAZIL AT THE EQUATOR AND 50W.
SCATTERED MODERATE/STRONG CONVECTION IS FROM 2N-6N BETWEEN
19W-40W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF OF MEXICO IS BEGINNING TO DRY OUT NOW THAT THE FRONTAL
BOUNDARY PREVIOUSLY IMPACTING THE BASIN HAS MOVED E OF FLORIDA
INTO THE W ATLC. MAINLY ZONAL WLY FLOW ACCOMPANIED BY DRY AIR
AND SUBSIDENCE ALOFT COVERS THE AREA AROUND THE BASE OF THE
LONGWAVE UPPER TROUGH SUPPORTING THE FRONT. SURFACE HIGH
PRESSURE IS BEGINNING TO FORM OVER THE EXTREME WRN GULF AROUND A
1020 MB HIGH NEAR SRN TEXAS AT 27N97W. A COOLER AIRMASS IS LEFT
IN THE WAKE OF THE FRONT ALONG WITH STRONG NW WINDS OF 20-25
KTS. LIGHTER ANTI-CYCLONIC WINDS ARE AROUND THE SURFACE HIGH
OVER THE NW GULF. EXPECT HIGH PRESSURE TO BUILD ACROSS THE BASIN
OVER THE NEXT SEVERAL DAYS AS THE FRONT CONTINUES TO MOVE EWD.
AS THE RIDGE MOVES IN WINDS WILL DIMINISH ACROSS THE BASIN.

CARIBBEAN SEA...
AS OF 2100 UTC...A COLD FRONT DRAPES ACROSS THE NW CARIBBEAN
EXTENDING FROM CENTRAL CUBA AT 22N78W TO E OF NICARAGUA ALONG
19N82W TO 14N83W. A PRE-FRONTAL SURFACE TROUGH IS E OF THE FRONT
ALONG 19N77W TO 15N82W. ISOLATED SHOWERS ARE WITHIN 30 NM E OF
THE FRONT WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN
90 NM SE OF THE SURFACE TROUGH. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ALSO CONTINUE NWD ACROSS JAMAICA...ERN CUBA...AND
HISPANIOLA. AN UPPER LEVEL TROUGH N OF THE AREA SUPPORTS THE
FRONT...BUT UPPER LEVEL RIDGING COVERS THE CARIBBEAN WITH AXIS
ALONG 67W. DRY AIR ALOFT COVERS BOTH THE NW CORNER AND THE ERN
PORTIONS WITH MOIST SWLY FLOW COVERING THE AREA OVER THE FRONT
CONTRIBUTING TO THE RAINFALL IN THAT AREA. THE DRY AIR IS
HELPING MAINTAIN FAIR CONDITIONS ACROSS MUCH OF THE CENTRAL AND
ERN CARIBBEAN. SHOWERS/THUNDERSTORMS ARE ALSO PRESENT OVER
PORTIONS OF CENTRAL AMERICA ESPECIALLY COSTA RICA AND
PANAMA...ALONG WITH NRN COLOMBIA AND VENEZUELA. LIGHT 10-15 KT
TRADEWIND FLOW DOMINATES THE CENTRAL AND ERN CARIBBEAN...WHILE
STRONGER 15-20 KT NW WINDS COVER THE NW CARIBBEAN W OF THE
FRONT. EXPECT THE FRONT TO CONTINUE TO MOVE EWD INTO THE CENTRAL
CARIBBEAN AND GRADUALLY DISSIPATE THROUGH THE BEGINNING OF THE
WEEK. SHOWERS/THUNDERSTORMS WILL LIKELY IMPACT MUCH OF THE NRN
CARIBBEAN ISLANDS AS THE FRONT PASSES THROUGH.

ATLANTIC OCEAN...
A DEEPENING LOW PRESSURE SYSTEM IS IMPACTING MUCH OF THE ERN
CONUS AND W ATLC TODAY CENTERED AROUND A 995 MB LOW OFF THE
COAST OF NORTH CAROLINA AT 34N77W. AS OF 2100 UTC...A COLD FRONT
EXTENDS FROM THE LOW CENTER ENTERING THE DISCUSSION AREA AT
32N75W TO THE CENTRAL BAHAMAS AT 25N76W ACROSS CUBA AT 22N78W
AND INTO THE CARIBBEAN. SCATTERED SHOWERS/THUNDERSTORMS ARE
MAINLY E OF THE FRONT EXTENDING TO 67W IMPACTING MUCH OF THE NRN
CARIBBEAN AND THE ERN BAHAMAS. A SURFACE TROUGH IS W OF THE
FRONT ALONG 31N78W TO 23N82W DEPICTING A SECOND WIND SHIFT.
PATCHES OF ISOLATED SHOWERS ARE BETWEEN THE FRONT AND TROUGH.
THIS SYSTEM IS SUPPORTED BY AN UPPER LEVEL TROUGH OVER THE NE
CONUS...WITH A SHORTWAVE TROUGH EXTENDING OFF OF IS FROM N
CAROLINA TO 29N71W. THE STRONGEST SHOWERS/THUNDERSTORMS ARE JUST
N OF THIS AXIS. AN UPPER LEVEL RIDGE IS TO THE E ALONG 63W
SUPPORTING A 1022 MB SURFACE HIGH NEAR 36N56W PROVIDING FAIR
CONDITIONS ACROSS THE CENTRAL ATLC. ANOTHER UPPER LEVEL TROUGH
IS ALONG 47W SUPPORTING A WEAKENING COLD FRONT ALONG 31N41W TO
23N47W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE WITHIN 100
NM E OF THE AXIS WITH ISOLATED SHOWERS WITHIN 100 NM W OF THE
AXIS. UPPER LEVEL RIDGING ALONG 32W COVERS THE ERN ATLC
SUPPORTING A 1030 MB AZORES HIGH NEAR 37N27W. THIS SURFACE RIDGE
IS PROVIDING FAIR CONDITIONS ACROSS THE ERN ATLC. EXPECT THE
FRONTAL BOUNDARY IN THE W ATLC TO CONTINUE TO MOVE EWD OVER THE
NEXT SEVERAL DAYS WITH LIKELY SHOWERS/THUNDERSTORMS IN THE
VICINITY.

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

$$
WALTON





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