[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211743
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT APR 21 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ/MONSOON TROUGH...

THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N12W TO
04N24W TO THE EQUATOR NEAR 31W. WIDELY SCATTERED MODERATE
CONVECTION IS S OF 05N BETWEEN 19W-35W.

...DISCUSSION...

GULF OF MEXICO...
A VIGOROUS MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE
NORTH-CENTRAL GULF NEAR 29N91W AND SUPPORTS A COMPLEX AREA OF
LOW PRESSURE ANALYZED AS A 1005 MB LOW CENTERED SOUTH OF THE
MISSISSIPPI RIVER DELTA NEAR 29N89W. WATER VAPOR INDICATES
MIDDLE TO UPPER LEVEL DIFFLUENCE CONTINUES TO ENHANCE CONVECTION
FOCUSED ALONG A WARM FRONT EXTENDING FROM THE LOW CENTER
SOUTHEASTWARD TO THE WESTERN FLORIDA STRAITS NEAR 24N84W.
NUMEROUS SHOWERS AND SCATTERED TSTMS ARE OCCURRING OVER MUCH OF
THE EASTERN GULF THIS AFTERNOON NORTH OF THIS WARM FRONT
BOUNDARY. A COLD FRONT ALSO EXTENDS FROM THE LOW TO THE MEXICO
COAST ALONG 25N92W TO 22N98W. N-NW WINDS IN THE RANGE OF 20 TO
25 KT REMAIN THE PRIMARY IMPACT WITH THIS COLD FRONT. A
SECONDARY COLD FRONT REMAINS ANALYZED OVER THE NW GULF WATERS
ENTERING THE BASIN NEAR 29N91W TO 27N95W. ALTHOUGH THE WIND
FIELD REMAINS UNIFORM ACROSS MUCH OF THE WESTERN GULF...THIS
FRONT IS LARGELY ASSOCIATED WITH THE LONGWAVE UPPER LEVEL
TROUGHING THAT EXTENDS ACROSS THE EASTERN CONUS AND CONTINUES TO
AID IN DEEPENING THE DEVELOPING SURFACE LOW AS IT IS FORECAST TO
SWEEP THE SYSTEM SWIFTLY OFF TO THE NE OVER THE NEXT 24 TO 36
HOURS. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING
BETWEEN THE TWO COLD FRONTS AND THIS ACTIVITY IS LIKELY ELEVATED
IN NATURE AND ASSOCIATED WITH THE STRONG MIDDLE LEVEL LOW AND
SHORTWAVE TROUGHING. AS THE LOW MOVES NE OF THE GULF BY EARLY
SUNDAY...NORTHERLY WINDS WILL DOMINATE SUNDAY INTO MONDAY AS
HIGH PRESSURE BUILDS INTO THE BASIN FROM THE CENTRAL AND
SOUTHERN PLAINS.

CARIBBEAN SEA...
SOUTHWEST TO WESTERLY UPPER LEVEL FLOW IS ACROSS THE CARIBBEAN
SEA THIS AFTERNOON WITH WATER VAPOR IMAGERY INDICATING THIS FLOW
IS WITHIN MODERATE DRY AIR AND OVERALL SUBSIDENCE. EASTERLY
TRADES IN THE RANGE OF 10 TO 15 KT E OF 80W QUICKLY VEER
SOUTHERLY W OF 80W AS LOW PRESSURE CONTINUES TO DEVELOP ACROSS
THE EASTERN GULF OF MEXICO. A FEW ISOLATED SHOWERS AND TSTMS ARE
OCCURRING ACROSS THE SW CARIBBEAN WITHIN THIS MOIST AND UNSTABLE
ENVIRONMENT ALONG A LINE FROM 15N83W TO 10N80W TO 09N76W.
LOOKING AHEAD OVER THE NEXT 24 TO 36 HOURS...THE LOW CENTERED IN
THE GULF OF MEXICO WILL MOVE NE INTO THE SW NORTH ATLC AND DRAPE
A COLD FRONT ACROSS CUBA INTO THE NW CARIBBEAN INTRODUCING W TO
NW WINDS IN THE RANGE OF 20 TO 25 KT. THE FRONT WILL EVENTUALLY
STALL OVER THE CENTRAL CARIBBEAN AS THE FRONTAL TROUGHING LIFTS
NORTH OF THE BASIN LATE TUESDAY INTO WEDNESDAY.

ATLANTIC OCEAN...
WITH A VIGOROUS MIDDLE TO UPPER LEVEL LOW CENTERED OVER THE
NORTH-CENTRAL GULF OF MEXICO THIS AFTERNOON...UPPER LEVEL
DIFFLUENCE SPREADS EASTWARD ACROSS THE FLORIDA PENINSULA AND
WESTERN PORTION OF THE SW NORTH ATLC PROVIDING FOR ISOLATED
SHOWERS AND TSTMS N OF 23N W OF 76W WITHIN MOIST UNSTABLE
SOUTHEASTERLY CONVERGENT LOW-LEVEL FLOW. FARTHER EAST...WEAK
UPPER LEVEL RIDGING INFLUENCES THE REMAINDER OF THE WESTERN ATLC
BETWEEN 55W-75W AS A SURFACE RIDGE CONTINUES TO HOLD FIRM
ANCHORED BY A 1020 MB HIGH CENTERED EAST OF BERMUDA NEAR 32N60W.
AN UPPER LEVEL LOW IS CENTERED NORTH OF THE DISCUSSION AREA OVER
THE CENTRAL ATLC AND SUPPORTS A COLD FRONT ANALYZED INTO THE
AREA NEAR 32N43W EXTENDING AS A DISSIPATING COLD FRONT TO
25N52W. A PRE-FRONTAL SURFACE TROUGH IS LOCATED TO THE SE OF THE
FRONT EXTENDING FROM 28N44W TO 21N50W TO 19N59W. LOW-LEVEL
MOISTURE CONVERGENCE IN THE VICINITY OF THE BOUNDARY CONTINUES
TO GENERATE ISOLATED SHOWERS WITHIN 150 NM EITHER SIDE OF THE
TROUGH AXIS. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED
S OF THE AZORES NEAR 36N28W.

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

$$
HUFFMAN




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