[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192344
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU APR 19 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.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS INLAND ACROSS THE TROPICAL REGIONS OF
WEST AFRICA INTO THE ATLC BASIN ACROSS THE COAST OF LIBERIA NEAR
6N10W TO 1N20W...WHERE THE ITCZ AXIS CONTINUES ALONG 1S30W TO
THE COAST OF BRAZIL NEAR 3S42W. SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION IS NOTED FROM THE EQUATOR TO 5N BETWEEN 5W AND
20W. ISOLATED TO SCATTERED MODERATE CONVECTION IS S OF 4N
BETWEEN 20W AND 34W.

...DISCUSSION...

GULF OF MEXICO...
A WEAK 1016 HIGH PRES LOCATED NEAR 28N91W DOMINATES THE WESTERN
HALF OF THE GULF PRODUCING MOSTLY FAIR WEATHER AND LIGHT WINDS.
A SHORTWAVE TROUGH MOVING ACROSS THE SE CONUS AND THE NE PORTION
OF THE GULF SUPPORTS A WEAK NEARLY STATIONARY LOW PRESSURE
SYSTEM CENTERED OVER THE FLORIDA PANHANDLE NEAR PANAMA CITY AND
ASSOCIATED COLD FRONT THAT EXTENDS SSW TO NEAR 26N84W. SOUTH
THIS POINT...THE FRONT IS BECOMING ILL DEFINED. DOPPLER RADAR
SHOWS SCATTERED SHOWERS AND TSTMS AHEAD OF THE LOW/FRONT OVER
THE STATE OF FLORIDA. THIS FRONT IS FORECAST TO SLOWLY MOVE
INLAND OVER CENTRAL FLORIDA TONIGHT BEFORE DISSIPATING ON FRI.
THE WEATHER PATTERN WILL START TO CHANGE ACROSS THE REGION LATE
FRI AS A DEEP LAYER UPPER TROUGH DEVELOPS OVER THE CENTRAL
UNITED STATES AND ALL THE WAY SOUTH INTO THE GULF OF MEXICO.
THIS FEATURE WILL SUPPORT THE DEVELOPMENT OF A SURFACE LOW PRES
IN THE NORTHERN GULF OF MEXICO BY SATURDAY WITH A STRONG COLD
FRONT EXTENDING SW ACROSS THE GULF WATERS. THE LOW PRES WILL
MOVE EWD ACROSS THE NORTHERN GULF WATERS INTO NORTHERN FLORIDA
THIS UPCOMING WEEKEND. THE FRONT WILL REACH FROM SE LOUISIANA TO
TAMPICO MEXICO EARLY SAT...THEN SWEEP SE OF THE AREA SUN. FRESH
TO STRONG WINDS AND BUILDING SEAS ARE EXPECTED IN THE WAKE OF
THE FRONT. STRONG TO SEVERE STORMS ARE POSSIBLE OVER PARTS OF
FLORIDA AHEAD OF THE FRONT THIS WEEKEND.

CARIBBEAN SEA...
HIGH PRES LOCATED N OF AREA WILL MAINTAIN MODERATE TO FRESH NE
TO E WINDS ACROSS THE BASIN THROUGH FRI. THE MOST RECENT
SCATTEROMETER DATA CONFIRMED THESE WIND SPEEDS. LATEST VIS
SATELLITE IMAGERY SHOWS A SWIRL OF LOW CLOUDS OVER THE GULF OF
HONDURAS AND A WEAK 1012 MB SURFACE LOW IS ANALYZED THERE.
SCATTERED SHOWERS AND ISOLATED TSTMS ARE NOTED OVER THE WESTERN
CARIBBEAN AND THE YUCATAN PENINSULA DUE TO THE PRESENCE OF A
WEAKENING STATIONARY FRONT. SIMILAR CONVECTION CAN BE FOUND OVER
THE SW CARIBBEAN IN ASSOCIATION WITH THE COLOMBIAN/PANAMANIAN
LOW SITUATED NEAR 10N77W. A TROUGH...REMNANT OF A COLD FRONT
ENTERS THE CARIBBEAN SEA THROUGH MARTINIQUE IN THE WINDWARD
ISLANDS. THIS TROUGH AND THE ASSOCIATED MOISTURE WILL CONTINUE
TO DRIFT WWD ACROSS THE EASTERN CARIBBEAN ON FRI. EXPECT
INCREASING WINDS ACROSS THE NW CARIBBEAN ON SAT AHEAD OF THE
COLD FRONT FORECAST TO MOVE ACROSS THE GULF OF MEXICO. THE
SOUTHERN PORTION OF THE COLD FRONT WILL MOVE ACROSS THE YUCATAN
CHANNEL SAT EVENING REACHING FROM CENTRAL CUBA TO NEAR CABO
GRACIAS A DIOS NICARAGUA SUN EVENING. FRESH W TO NW WINDS AREA
EXPECTED BEHIND THE FRONT. ALOFT...A RIDGE CURRENTLY DOMINATES
THE BASIN WITH SOME INCREASE IN MID/UPPER LEVEL MOISTURE OVER
THE CENTRAL CARIBBEAN AHEAD OF A SHORTWAVE TROUGH LOCATED OVER
THE FAR WEST PART OF THE BASIN.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE OVER THE WRN ATLC SUPPORTS A WEAK 1019 MB
SURFACE HIGH NEAR 29N73W MAINTAINING MOSTLY FAIR WEATHER
CONDITIONS AND LIGHT WINDS. SW AND W OF THIS RIDGE...SE TO S
WINDS OF 10 TO 15 KT ARE BLOWING. THESE WINDS WILL FURTHER
INCREASE TO 25 TO 30 KT LATE SAT AHEAD OF THE NEXT COLD FRONT
FORECAST TO MOVE OFF THE SE U.S. COAST BY SUN. THE HIGH PRES
WILL MOVE NE TOWARD THE BERMUDAS IN ABOUT 24 HOURS. SATELLITE
IMAGERY ALONG WITH SCATTEROMETER DATA SHOW VERY WELL THE
PRESENCE OF A 1006 MB LOW PRES LOCATED NEAR 29N55W. A SWIRL OF
LOW CLOUDS IS ASSOCIATED WITH THE LOW PRES FORECAST TO MOVE N OF
AREA DURING THE NEXT 24 HOURS. THE ATTENDANT COLD FRONT IS WELL
DISPLACED TO THE EAST AND ENTERS THE FORECAST REGION NEAR 31N47W
THEN CONTINUES SW TO 22N53W WHERE IT BEGINS TO DISSIPATE.
SCATTERED SHOWERS AND TSTMS ARE NOTED WITHIN 150 NM AHEAD OF THE
FRONT N OF 28N. FRESH TO STRONG SLY WINDS ARE ALSO SEEN AHEAD OF
THE FRONT THANKS TO THE PRES GRADIENT BETWEEN THE LOW PRES AND A
HIGH CENTERED NEAR THE AZORES. THIS HIGH EXTENDS A RIDGE OVER
THE EASTERN ATLC. A SURFACE TROUGH IS OVER THE TROPICAL N ATLC
WATERS JUST E OF THE LESSER ANTILLES ANALYZED FROM 17N57W TO
11N62W. MOISTURE ASSOCIATED WITH THIS TROUGH WILL DRIFT WWD INTO
THE CARIBBEAN SEA. A BAND OF TRANSVERSE HIGH CLOUDS EXTENDS FROM
NORTHERN SOUTH AMERICA ACROSS THE WINDWARD ISLANDS INTO THE ATLC
AROUND THE BASE OF AN UPPER LEVEL TROUGH EXTENDING BETWEEN 50W
AND 60W...THEN ACROSS THE N PORTION OF A RIDGE ANCHORED ON A
HIGH NEAR 7N36W.

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

$$

GR





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