[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 072346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED NOV 07 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.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
09N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
09N20W TO 06N33W TO 09N50W. SCATTERED MODERATE CONVECTION IS
FROM 03N-05N BETWEEN 15W-21W...AND FROM 04N-09N BETWEEN 21W-28W.
ISOLATED MODERATE CONVECTION IS FROM 05N-10N BETWEEN 36W-48W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES WEST-NORTHWESTERLY WINDS PREVAIL
ALOFT WITHIN A VERY DRY AND STABLE AIRMASS CURRENTLY LOCATED
OVER THE GULF BASIN THIS EVENING. THE NORTHERLY FLOW IN THE
MIDDLE TO UPPER LEVELS IS FURTHER SUPPORTING A BROAD SURFACE
RIDGE ANCHORED BY A 1022 MB HIGH CENTERED NEAR BROWNSVILLE
TEXAS. THE SURFACE RIDGE AXIS EXTENDS NORTHWARD ACROSS THE
CENTRAL PLAINS AND IS EXPECTED TO BUILD SOUTHEASTWARD THROUGH
LATE FRIDAY INTO THE SE CONUS. NORTHERLY SURFACE WINDS IN THE
RANGE OF 10 TO 20 KT ARE EXPECTED TO VEER NORTHEASTERLY BY LATE
THURSDAY AND BECOME EAST-SOUTHEASTERLY BY EARLY SATURDAY. FOR
THE UPCOMING WEEKEND...GLOBAL MODELS INDICATE AS THE SURFACE
HIGH EXTENDS INFLUENCE OVER THE EASTERN GULF...FLORIDA
PENINSULA...AND AREAS SOUTH OF 23N...THE PRESSURE GRADIENT WILL
STRENGTHEN AND PROVIDE FOR STRONGER WINDS ACROSS THE FLORIDA
STRAITS AND PORTIONS OF THE SE GULF. THE STRONGER WINDS ARE
EXPECTED TO SPREAD WESTWARD BY MONDAY AS THE NEXT COLD FRONT
MOVES ACROSS THE MID-MISSISSIPPI RIVER VALLEY AND PORTIONS OF
EASTERN TEXAS INTO THE FAR NW GULF WATERS.

CARIBBEAN SEA...
A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR
15N68W OVER THE EASTERN CARIBBEAN AND EXTENDS INFLUENCE AS FAR
WEST AS 85W OVER PORTIONS OF CENTRAL AMERICA. THE WESTERN
CARIBBEAN IS INFLUENCED BY MIDDLE TO UPPER LEVEL SOUTHWESTERLY
WINDS ALOFT N OF 15N AND A COLD FRONT ANALYZED FROM WESTERN CUBA
NEAR 23N80W TO 19N90W GENERATING ISOLATED SHOWERS WITHIN 90 NM
EITHER SIDE OF THE COLD FRONT AND WITHIN 120 NM EITHER SIDE OF A
LINE FROM 21N76W TO 15N88W DUE TO MAXIMUM MIDDLE TO UPPER LEVEL
DIFFLUENCE. FARTHER SOUTH OVER THE SW CARIBBEAN...THE MONSOON
TROUGH AXIS EXTENDS FROM WESTERN PANAMA NEAR 09N82W TO NORTHERN
COLOMBIA NEAR 11N75W AND IS PROVIDING FOCUS FOR SCATTERED
SHOWERS AND ISOLATED TSTMS FROM 08N-15N BETWEEN 74W-85W. THE
REMAINDER OF THE EASTERN CARIBBEAN IS UNDER THE INFLUENCE OF A
VERY DRY AIRMASS ALOFT WHICH IS RESULTING IN VERY DRY CONDITIONS
AND CLEAR SKIES AT THE SURFACE E OF 73W.

ATLANTIC OCEAN...
A BROAD AND DEEP MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE
MID-ATLC STATES THAT CONTINUES TO SUPPORT BROAD TROUGHING OVER
THE FLORIDA PENINSULA AND SW NORTH ATLC N OF 22N W OF 65W. WATER
VAPOR IMAGERY INDICATES A FAIRLY DRY AIRMASS IS LOCATED ON THE
SOUTHERN PERIPHERY OF THE UPPER LEVEL LOW AND IS LIMITING ANY
SIGNIFICANT DEEP CONVECTION EVEN WITH THE PRESENCE OF A COLD
FRONT AND WAVE OF ENERGY ASSOCIATED WITH A SECONDARY SURFACE
TROUGH. THE COLD FRONT IS ANALYZED FROM 32N68W SW TO THE CENTRAL
BAHAMAS NEAR 25N76W TO WESTERN CUBA NEAR 23N80W. ISOLATED
SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE FRONT...
HOWEVER THESE ARE REMAINING LOW-TOPPED AND QUICKLY MOVING TO THE
NORTHEAST. THE FRONT CONTINUES TO BECOME MORE AND MORE DIFFUSE
WITH THE SECONDARY WAVE OF ENERGY IN THE FORM OF A SURFACE
TROUGH FROM 32N73W TO 28N80W POISED TO BECOME THE DOMINATE
FEATURE IN 24 TO 36 HOURS. A PRE-FRONTAL SURFACE TROUGH IS
ANALYZED FROM 28N65W TO 23N73W AND IS PROVIDING LOW-LEVEL
MOISTURE CONVERGENCE TO SUPPORT ISOLATED SHOWERS FROM 21N-29N
BETWEEN 54W-70W. THIS CONVECTION CONTINUES TO BE ENHANCED BY
STRONG MIDDLE TO UPPER LEVEL DIFFLUENCE AND SPREADS NORTHEAST
COVERING THE ADDITIONAL AREA OF SCATTERED SHOWERS AND TSTMS FROM
26N-36N BETWEEN 52W-62W. ELSEWHERE OVER THE REMAINDER OF THE
EASTERN ATLC...SURFACE RIDGING DOMINATES ANCHORED BY A 1035 MB
HIGH CENTERED WEST OF THE AZORES NEAR 40N33W. HOWEVER...A WEAK
SURFACE TROUGH REMAINS EMBEDDED WITHIN THE SOUTHERN PERIPHERY OF
THE RIDGE MOVING SLOWLY WESTWARD ANALYZED FROM 15N-22N ALONG
44W. THE SURFACE TROUGH ALONG WITH AN UPPER LEVEL TROUGH AXIS
FROM 28N41W TO 18N36W IS GENERATING WIDELY SCATTERED SHOWERS AND
ISOLATED TSTMS FROM 15N-28N BETWEEN 30W-39W.

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

$$
HUFFMAN




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