[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 142348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED NOV 14 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 2300 UTC.

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

THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA THROUGH THE COAST
OF SIERRA LEONE AT 9N13W TO 8N16W. THE ITCZ BEGINS AT 8N16W AND
CONTINUES ALONG 8N33W 6N43W 3N51W. SCATTERED MODERATE/STRONG
CONVECTION IS FROM 7N-8N BETWEEN 14W-17W...AND FROM 7N-14N
BETWEEN 25W-31W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS FROM 5N-7N BETWEEN 30W-34W...AND FROM 8N-11N BETWEEN
34W-39W.

...DISCUSSION...

THE GULF OF MEXICO...
BROAD UPPER LEVEL TROUGHING COVERS THE GULF OF MEXICO SUPPORTING
A DISSIPATING STATIONARY FRONT FROM JUST SOUTH OF TAMPA FLORIDA
NEAR 27N82W TO THE SW GULF ALONG 23N94W 18N94W. ISOLATED
SHOWERS/THUNDERSTORMS ARE WITHIN 160 NM SOUTH OF THE AXIS. AS OF
2100 UTC...A SURFACE TROUGH IS NORTH OF THE FRONT ALONG 31N86W
TO 28N86W SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS WITHIN 60 NM
EITHER SIDE OF THE AXIS. THIS SURFACE TROUGH IS ASSOCIATED WITH
A SHORTWAVE UPPER TROUGH MOVING OVER NORTH FLORIDA. DRY AIR
ALOFT IS SINKING AROUND THE WEST SIDE OF THE LONGWAVE UPPER
TROUGH SUPPORTING FAIR CONDITIONS IN THE FAR NW GULF. MAINLY
10-15 KT NE FLOW IS SOUTH OF THE FRONT WITH SLIGHTLY STRONGER
WINDS NORTH OF THE FRONT REACHING 20-25 KT NORTH OF THE AXIS IN
THE WESTERN GULF. THE FRONT IS EXPECTED TO CONTINUE TO DISSIPATE
OVER THE BASIN AS SURFACE RIDGING BUILDS TO THE NORTH. MOISTURE
NEAR THE TAIL END OF THE FRONT IN THE SW GULF WILL LIKELY REMAIN
THERE SUPPORTING SHOWERS/THUNDERSTORMS.

THE CARIBBEAN SEA...
MOSTLY FAIR CONDITIONS ARE ACROSS THE CARIBBEAN DUE TO DRY AIR
ALOFT WRAPPING AROUND THE BASE OF A LONGWAVE UPPER TROUGH OVER
THE EASTERN CONUS AND AN UPPER LEVEL RIDGE OVER THE EASTERN
CARIBBEAN. A FEW ISOLATED SHOWERS ARE IN THE NW CARIBBEAN FROM
17N-20N BETWEEN 82W-85W. HEAVIER SHOWERS/THUNDERSTORMS ARE IN
THE EXTREME SW CARIBBEAN SOUTH OF 12N BETWEEN 78W-84W ACROSS
COSTA RICA AND PANAMA ASSOCIATED WITH THE MONSOON TROUGH JUST
SOUTH OF THE COUNTRIES. A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE
ALSO EMBEDDED WITHIN THE NE-E 15 KT SURFACE FLOW IN THE CENTRAL
CARIBBEAN. A WEAK SURFACE TROUGH IS ANALYZED IN THE EASTERN
CARIBBEAN ALONG 16N63W TO 13N63W SUPPORTING A FEW ISOLATED
SHOWERS IN ITS VICINITY. THE TROUGH WILL BE SHORT-LIVED. LITTLE
CHANGE IS EXPECTED OVER THE NEXT 24 HOURS.

THE ATLANTIC OCEAN...
A STATIONARY FRONT REMAINS IN THE FAR NW CORNER OF THE
DISCUSSION AREA IN THE WEST ATLC ALONG 32N74W 31N79W 28N81W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE MAINLY NORTH OF THE
BOUNDARY. THE FRONT IS SUPPORTED BY A SHORTWAVE TROUGH EMBEDDED
WITHIN A LONGWAVE TROUGH COVERING THE EASTERN CONUS. ANOTHER
SHORTWAVE FARTHER EAST IS SUPPORTING A WEAK 1013 MB SURFACE LOW
NEAR 32N65W WITH A SURFACE TROUGH EXTENDING FROM THE LOW CENTER
TO NEAR 27N69W. A FEW SHOWERS/POSSIBLE THUNDERSTORMS ARE WEST OF
THE AXIS FROM 28N-30N BETWEEN 69W-71W. DIFFLUENCE ALOFT BETWEEN
THE LARGE CIRCULATION AROUND THE LONGWAVE TROUGH AND AN UPPER
LEVEL RIDGE OVER THE CENTRAL ATLC NEAR 55W IS SUPPORTING A FEW
SHOWERS/THUNDERSTORMS NORTH OF HISPANIOLA AS WELL AS FARTHER
NORTH FROM 24N-31N BETWEEN 56W-58W. A WEAK SURFACE TROUGH IS
ALONG 24N52W TO 21N50W...BUT IS NOT CAUSING ANY ACTIVE WEATHER.
THE UPPER LEVEL RIDGE OVER THE CENTRAL ATLC IS SUPPORTING A
BROAD SURFACE RIDGE A 1036 MB HIGH WELL NORTH OF THE AREA NEAR
43N46W PROVIDING FAIR WEATHER ACROSS THE REMAINDER OF THE
CENTRAL ATLC. AN UPPER LEVEL LOW IS IMPACTING THE EASTERN ATLC
CENTERED NEAR 38N21W. THE UPPER LOW SUPPORTS A SURFACE LOW AND
ASSOCIATED COLD FRONT THAT ENTERS THE AREA NEAR 32N16W AND
CONTINUES ALONG 27N20W 26N30W. POSSIBLE ISOLATED SHOWERS ARE
ALONG THE AXIS. AN UPPER LEVEL TROUGH EXTENDS FROM THE UPPER LOW
CIRCULATION ALONG 25N42W TO 12N42W. THIS UPPER TROUGH SUPPORTS A
SURFACE TROUGH ALONG 16N40W TO 11N41W...ALONG WITH A LARGE AREA
OF SHOWERS/THUNDERSTORMS FROM 10N-19N BETWEEN 32W-39W. THIS
ACTIVITY CONTINUES TO THE ITCZ REGION WHERE THE UPPER TROUGH IS
ALSO ENHANCING ACTIVITY.

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

$$
WALTON





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