[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181745
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI APR 18 2014

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.

...SPECIAL FEATURE...
A GALE WARNING REMAINS IN EFFECT FOR THE NE GULF IN ASSOCIATION
WITH A DEEPENING AREA OF LOW PRES LOCATED NEAR 28.5N87W AT 1200
UTC. THE LOW WILL SHIFT SLOWLY NE...MOVING INLAND ACROSS THE
CENTRAL FLORIDA PANHANDLE LATE THIS AFTERNOON...THEN WILL
CONTINUE NE OVERNIGHT AND EXIT THE GEORGIA COAST SAT MORNING.
MINIMAL GALE FORCE WINDS ARE EXPECTED BRIEFLY ACROSS N AND NW
PORTIONS OF LOW THIS AFTERNOON...WITH FREQUENT GUSTS TO GALE
FORCE OVER THE NE GULF AHEAD OF THE LOW AND THE ASSOCIATED COLD
FRONT. IN FACT...THE 1524 UTC ASCAT PASS CONFIRMED THE PRESENCE
OF MINIMAL GALE FORCE WINDS WITHIN AROUND 70 NM ON THE NW
QUADRANT OF THE LOW CENTER. PLEASE SEE THE HIGH SEAS FORECAST
UNDER AWIPS/WMO HEADERS MIAHSFAT2/ FZNT02 KNHC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC
NEAR 14N17W AND CONTINUES TO NEAR 4N24W WHERE THE ITCZ BEGINS
AND CONTINUES ALONG 1N30W THEN S OF THE EQUATOR TO NEAR 2S44W.
SCATTERED MODERATE CONVECTION IS NOTED WITHIN 90 NM EITHER SIDE
OF THE ITCZ AXIS BETWEEN 24W AND 30W. SIMILAR CONVECTION CAN BE
FOUND S OF 2N TO THE COAST OF SOUTH AMERICA BETWEEN 44W AND 47W.
A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 30
NM OF 6N13W.

...DISCUSSION...
AN AREA OF LOW PRES HAS DEVELOPED ACROSS THE GULF OF MEXICO AND
IS CENTERED NEAR 28.5N87W AT 1200 UTC. A COLD FRONT EXTENDS FROM
THE LOW CENTER TO NEAR TAMPICO MEXICO. THE MOSAIC DOPPLER RADAR
FROM THE SE U.S. SHOWS NUMEROUS SHOWERS WITH EMBEDDED TSTMS
COVERING MAINLY THE FLORIDA PANHANDLE AND THE NE GULF. A FLASH
FLOOD WATCH REMAINS IN EFFECT FOR PARTS OF SOUTH-CENTRAL
ALABAMA...THE FLORIDA PANHANDLE...NORTHERN FLORIDA AND SOUTHERN
GEORGIA. THE LOW PRES IS FORECAST TO IMPACT THE REGION THROUGH
TONIGHT SPREADING AREA OF HEAVY RAINFALL. LATEST SURFACE OBS
INDICATE WINDS OF 20-25 KT E OF THIS DEEPENING LOW PRES OVER THE
NE GULF. WINDS HAVE INCREASED TO MINIMAL GALE FORCE ON THE NW
QUADRANT OF THE LOW CENTER PER THE MOST RECENT ASCAT PASS.  THE
LOW PRES WILL MOVE SLOWLY NE TOWARD NORTHERN FLORIDA EMERGING
INTO THE SW N ATLC ON SAT MORNING. THE ASSOCIATED COLD FRONT
WILL MOVE ACROSS THE FLORIDA PENINSULA TONIGHT INTO SAT MORNING.
IN ITS WAKE...A RIDGE WILL THEN EXTEND ACROSS THE GULF THE
REMAINDER OF THE UPCOMING WEEKEND. PLEASE SEE SPECIAL FEATURE.
ALOFT...A DEEPENING UPPER LEVEL TROUGH SUPPORTS THE LOW PRES
SYSTEM. THE TROUGH EXTENDS FROM LOUISIANA TO OVER THE W GULF
AMPLIFYING AN UPPER RIDGE ACROSS THE EASTERN GULF AND FLORIDA.
UPPER DIFFLUENCE RELATED TO THIS UPPER-LEVEL RIDGE IS HELPING TO
INDUCE THE CONVECTIVE ACTIVITY ASSOCIATED WITH THE ABOVE
MENTIONED AREA OF LOW PRES. A WIDE-BAND OF SHOWERS WITH TSTMS
HAS DEVELOPED AHEAD OF THE FRONT AND COULD PRODUCE STRONG TO
SEVERE THUNDERSTORMS OVER PARTS OF FLORIDA TONIGHT INTO SAT
MORNING.

CARIBBEAN SEA...
AN EARLIER SCATTEROMETER PASS PROVIDED OBSERVATIONS OF 25-30 KT
WINDS NEAR THE COAST OF COLOMBIA. MODERATE TO FRESH TRADE WINDS
ARE NOTED ACROSS THE EAST AND CENTRAL CARIBBEAN WITH LIGHTER
WINDS ACROSS THE WESTERN PAR OF THE BASIN. HIGH PRES CENTERED
OVER THE CENTRAL ATLC EXTENDS A RIDGE SW COVERING THE NE
CARIBBEAN...INCLUDING PUERTO RICO AND THE US/UK VIRGIN ISLANDS.
THE SAN JUAN DOPPLER RADAR SHOWS QUICK PASSING SHOWERS EMBEDDED
IN THE TRADE WIND FLOW MOVING ACROSS THE ISLANDS AND REGIONAL
COASTAL WATERS. TYPICAL TRADE WIND SHOWERS ARE ALSO SEEN ON
VISIBLE SATELLITE IMAGERY CROSSING THE LESSER ANTILLES IN TO THE
EASTERN CARIBBEAN. THE HIGH PRES IS FORECAST TO MOVE SOUTH
DURING THE NEXT 24 HOURS. THIS PATTERN WILL MAINTAIN FRESH TO
LOCALLY STRONG TRADES NEAR THE COAST OF COLOMBIA WITH MODERATE
TO LOCALLY FRESH TRADES ELSEWHERE THROUGH SAT...WITH WINDS THEN
WEAKENING SUN AS LOW PRES MOVES N OF AREA AND THE HIGH PRES
WEAKENS. IN THE UPPER-LEVELS...BROAD UPPER RIDGE COVERS THE
CARIBBEAN WITH THE AXIS EXTENDING FROM NW VENEZUELA ACROSS EAST-
CENTRAL CUBA INTO THE SW ATLC.

...HISPANIOLA...
CURRENTLY...SE WINDS AROUND THE SOUTHERN PERIPHERY OF THE ATLC
RIDGE ARE TRANSPORTING PATCHES OF LOW LEVEL CLOUDS WITH EMBEDDED
SHOWERS ACROSS OF THE ISLAND. LITTLE CHANGE IS EXPECTED IN THE
WEATHER PATTERN DURING THE WEEKEND. SOME DRIER AIR WILL BEGIN TO
FILTER IN FROM THE EAST ON SAT RESULTING IN ISOLATED TO
SCATTERED SHOWERS. EXPECT INCREASING MOISTURE LATE SUN INTO MON
AS A COLD FRONT APPROACHES FROM THE WEST.

ATLANTIC OCEAN...
A WEAKENING STATIONARY FRONT EXTENDING FROM 31N74W TO NEAR COCOA
BEACH FLORIDA HAS BEGUN TO LIFT N AS A WARM FRONT ACROSS FLORIDA
THIS MORNING...AND WILL LIFT N OF AREA BY LATE THIS AFTERNOON AS
LOW PRES OVER THE NE GULF OF MEXICO MOVES SLOWLY NE...AND ACROSS
NORTHERN FLORIDA TONIGHT...EXITING GEORGIA COAST SAT MORNING.
FREEPORT IN THE NW BAHAMAS REPORTED 2.31 INCHES OF RAIN LIKELY
WITH THE FRONTAL PASSAGE. THE ASSOCIATED COLD FRONT WILL REACH
FROM 31N78W TO FLORIDA KEYS SAT AFTERNOON...THEN EXTEND FROM
BERMUDA TO TURKS AND CAICOS ISLANDS MON EVENING. FRESH TO STRONG
NORTHERLY WINDS ARE EXPECTED AHEAD AND BEHIND THE FRONT AS PRES
GRADIENT TIGHTENS BETWEEN THE LOW PRES AND THE ATLC RIDGE. A
1032 MB HIGH PRES CENTERED NEAR 36N54W EXTENDS A RIDGE ACROSS
THE REMAINDER OF THE WEST AND CENTRAL ATLC. MODERATE TO FRESH
TRADES ARE SEEN ACROSS THE TROPICAL ATLC ON THE SOUTHERN
PERIPHERY OF THE RIDGE. A WEAK 1019 MB HIGH IS SITUATED NEAR
29N20W AND WILL DISSIPATE IN ABOUT 24 HOURS. ALOFT...THE UPPER
RIDGE FROM THE CARIBBEAN EXTENDS OVER THE W ATLC WITH THE AXIS
ALONG 75W. AN UPPER TROUGH EXTENDS FROM THE NE ATLC TO OVER THE
CENTRAL ATLC SUPPORTING A SURFACE TROUGH THAT LIES OVER THE
EASTERN ATLC AND STRETCHES FROM A LOW PRES LOCATED WELL N OF
AREA TO 31N29W TO 26N36W.

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

$$
GR


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