[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 181753
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN APR 18 2010

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC...

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N11W 3N19W 2N30W 2N40W AND INTO NE
BRAZIL NEAR THE EQUATOR AND 49W. SCATTERED MODERATE ISOLATED
STRONG CONVECTION IS FROM 2N-7N BETWEEN 06W-16W. SIMILAR
CONVECTION IS FROM THE EQUATOR TO 6N BETWEEN 21W-36W.

...DISCUSSION...

GULF OF MEXICO...
AN AMPLIFIED UPPER LEVEL TROUGH IS LOCATED ACROSS THE GULF OF
MEXICO WITH AXIS EXTENDING ALONG 90W. THIS PARTICULAR UPPER
LEVEL TROUGH AXIS EXTENDS FROM SE LOUISIANA FAR SOUTH CROSSING
PORTIONS OF NORTHERN CENTRAL AMERICA INTO THE E PACIFIC REGION
TO 05N. THIS UPPER LEVEL FEATURE IS SUPPORTING A 1008 MB LOW
CENTERED IN THE SE GULF NEAR 25N85W WITH A DEVELOPING WARM FRONT
EXTENDING EASTWARD FROM THE LOW INTO THE STRAITS OF FLORIDA AND
ACROSS THE CENTRAL BAHAMAS IN THE W ATLC. ALSO...A SURFACE
TROUGH IS ANALYZED FROM THE LOW TO THE YUCATAN PENINSULA NEAR
21N88W AND INTO THE EASTERN BAY OF CAMPECHE NEAR 19N92W.
LOW-LEVEL CONVERGENCE IN THE VICINITY OF THE LOW COUPLED WITH
MIDDLE TO UPPER LEVEL LIFTING DYNAMICS ASSOCIATED WITH THE UPPER
LEVEL TROUGH AXIS ARE GENERATING NUMEROUS SHOWERS AND SCATTERED
TSTMS FROM 24N-29N E OF 86W TO INLAND OVER THE FLORIDA
PENINSULA. MEANWHILE...AN UPPER LEVEL SHORTWAVE TROUGH EMBEDDED
WITHIN THE MEAN TROUGH PREVIOUSLY MENTIONED IS LOCATED OVER SE
TEXAS AND SUPPORTS A COLD FRONT THAT ENTERS THE NW GULF WATERS
NEAR SAN ANTONIO BAY AND INLAND ONCE AGAIN NEAR BAFFIN BAY.
MOSAIC DOPPLER RADAR INDICATES SCATTERED SHOWERS AND ISOLATED
TSTMS WITHIN 60 NM EAST OF THE FRONT. A PRE-FRONTAL SURFACE
TROUGH EXTENDS FROM JUST NORTH OF BROWNSVILLE TEXAS INTO THE SW
GULF TO 21N94W. ISOLATED SHOWERS ARE OVER THE WESTERN GULF S OF
26N W OF 94W. GLOBAL MODEL GUIDANCE INDICATES THE SURFACE LOW
OVER THE SE GULF IS FORECAST TO DRIFT NE OVER THE NEXT 24 HOURS
BRINGING AMPLE MOISTURE ACROSS THE FLORIDA PENINSULA AND STRAITS
OF FLORIDA. THIS LOW IS EXPECTED TO BE ABSORBED INTO A FRONTAL
TROUGH THROUGH LATE MONDAY AS A WEAK FRONTAL BOUNDARY LINGERS
ACROSS THE W ATLC AND NORTHERN FLORIDA ALONG 30N.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH IS ALONG 90W IN THE GULF OF MEXICO AND
CONTINUES TO PROVIDE THE NW CARIBBEAN WITH PRONOUNCED MOIST
SOUTHWESTERLY UPPER LEVEL FLOW W OF 70W. LOW-LEVEL CONVERGENCE
OF E-SE SURFACE FLOW OVER THE WESTERN CARIBBEAN AND UPPER LEVEL
DIFFLUENCE ASSOCIATED WITH THE APPROACHING UPPER LEVEL TROUGH
ARE GENERATING SCATTERED SHOWERS ISOLATED TSTMS WITHIN 120 NM
EITHER SIDE OF A LINE FROM EASTERN CUBA NEAR 20N75W TO JAMAICA
THEN SW TO OFFSHORE OF NORTHEASTERN NICARAGUA NEAR 13N83W. OF
NOTE WITH THIS PERSISTENT RAINFALL OVER JAMAICA...2.80 INCHES OF
PRECIPITATION HAD BEEN RECORDED AT KINGSTON OVER THE LAST 24
HOURS. AS A FRONTAL TROUGH DEVELOPS NORTH OF THE CARIBBEAN
SEA...EASTERLY TRADES AND NORTHERLY WINDS FILTERING INTO THE NW
CARIBBEAN WILL PROVIDE FOR CONTINUED SCATTERED SHOWERS OVER THE
CENTRAL CARIBBEAN...INCLUDING HISPANIOLA...JAMAICA...EASTERN
CUBA...AND THE WINDWARD PASSAGE. ELSEWHERE ACROSS THE EASTERN
CARIBBEAN...THE TAIL END OF A REMNANT FRONT...ANALYZED NOW AS A
SHEARLINE...EXTENDS FROM THE TROPICAL NORTH ATLC ACROSS BARBADOS
AND THE GRENADINES TO 13N64W. THE SHEARLINE CONTINUES TO PROVIDE
FOCUS FOR LOW-LEVEL MOISTURE GENERATING ISOLATED SHOWERS OVER
THE EASTERN CARIBBEAN E OF 66W.

ATLANTIC OCEAN...
WATER VAPOR IMAGERY SHOWS UPPER LEVEL DIFFLUENCE OCCURRING OVER
A LARGE PORTION OF THE W ATLC WEST OF 70W AHEAD OF AN UPPER
LEVEL TROUGH POSITIONED OVER THE CENTRAL GULF OF MEXICO.
MOISTURE CONTINUES TO ADVECT FROM THE FAR EASTERN PACIFIC REGION
AND WESTERN CARIBBEAN NORTHEASTWARD OVER THE FLORIDA PENINSULA
AND W ATLC...SUPPORTING SCATTERED TO NUMEROUS SHOWERS W OF 77W.
WITH A SURFACE LOW CONTINUING TO DEVELOP IN THE SE GULF OF
MEXICO...A WARM FRONT EXTENDS FROM THE LOW CENTERED NEAR 25N85W
THROUGH THE FLORIDA STRAITS TO 23N73W. ISOLATED SHOWERS ARE
OCCURRING FROM 20N-31N BETWEEN 66W-77W MAINLY NORTH OF THIS
FRONTAL BOUNDARY. ELSEWHERE ACROSS THE REMAINDER OF THE WESTERN
AND CENTRAL ATLC...A 1021 MB HIGH IS CENTERED NEAR 27N59W AND
SUPPORTS MOSTLY FAIR WEATHER N OF 18N BETWEEN 40W-67W. FARTHER
EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 40N37W THAT EXTENDS A
TROUGH AXIS ALONG 35W TO 20N. THIS UPPER LEVEL FEATURE SUPPORTS
A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N27W AND
CONTINUES SW ALONG 27N30W 17N44W BECOMING STATIONARY TO 13N52W
AND THEN ANALYZED AS A SHEARLINE TO BARBADOS AND THE GRENADINES
NEAR 13N61W. SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS ARE
WITHIN 150 NM EAST OF THE COLD FRONT N OF 22N...WHILE ISOLATED
SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE REMAINDER OF THE
BOUNDARY S OF 22N. ELSEWHERE OVER THE EASTERN ATLC...A 1018 MB
SURFACE HIGH IS CENTERED OVER THE SW CANARY ISLANDS AND
CONTINUES TO EXTENDS A RIDGE AXIS S-SW TO THE CAPE VERDE ISLANDS
PROVIDING GENERALLY FAIR WEATHER AND CLEAR SKIES THIS AFTERNOON.

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

$$
HUFFMAN




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