[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081732
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT DEC 08 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH CURRENTLY DOES NOT EXTEND OVER ATLC WATERS.
THE ITCZ EXTENDS FROM THE COAST OF LIBERIA AT 6N10W ALONG 5N34W
7N46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
5N-8N BETWEEN 28W-46W. ISOLATED MODERATE/STRONG CONVECTION IS
FROM 1N-5N BETWEEN 26W-45W.

...DISCUSSION...

THE GULF OF MEXICO...
MAINLY ZONAL WESTERLY FLOW COVERS THE GULF OF MEXICO AROUND A
BROAD UPPER LEVEL RIDGE THAT CONTINUES INTO THE NW CARIBBEAN. AT
THE SURFACE...A WEAK SURFACE RIDGE SPREADS OVER THE BASIN FROM A
1018 MB HIGH OVER GEORGIA PROVIDING MOSTLY FAIR CONDITIONS
ACROSS THE AREA. LIGHT SOUTHEAST-SOUTH WINDS COVER THE EASTERN
GULF AND CONTINUE WESTWARD WHILE INCREASING IN SPEED TO NEAR 15
KT. A WEAK SURFACE TROUGH IS ANALYZED IN THE NE GULF ALONG
31N89W TO 27N86W. A FEW ISOLATED SHOWERS ARE NEAR THE TROUGH. A
LINE OF SHOWERS ALSO EXTENDS FROM NORTH OF THE YUCATAN PENINSULA
TO THE COAST OF TEXAS NEAR 29N94W. SATELLITE IMAGERY ALONG WITH
SURFACE OBSERVATIONS INDICATE THAT AN AREA OF FOG COVERS MUCH OF
NORTHERN FLORIDA AS WELL AS ALONG OTHER PORTIONS OF THE GULF
COAST. FINALLY...RADAR IMAGERY INDICATES A SCATTERED SHOWERS ARE
MOVING THROUGH THE FLORIDA KEYS. LITTLE CHANGE IS EXPECTED OVER
THE NEXT 24 HOURS. HOWEVER...MOISTURE IS EXPECTED TO INCREASE
ACROSS THE SE GULF AT THE BEGINNING OF THE WEEK...AND A COLD
FRONT IS EXPECTED TO MOVE INTO THE NW GULF ON MONDAY.


THE CARIBBEAN SEA...
MOSTLY DRY AIR ALOFT COVERS THE WESTERN HALF OF THE CARIBBEAN
AROUND AN UPPER LEVEL RIDGE COVERING THE NW CORNER AND AROUND
THE WEST SIDE OF AN UPPER LEVEL TROUGH EXTENDING FROM THE
WINDWARD PASSAGE TO COSTA RICA. MOSTLY FAIR CONDITIONS ARE NOTED
ACROSS THIS AREA. HOWEVER...A SURFACE TROUGH IS ALONG 19N80W TO
12N81W SUPPORTING ISOLATED SHOWERS WITHIN 120 NM WEST OF THE
AXIS AND FROM 18N-20N BETWEEN 75W-80W. SLIGHTLY HIGHER MOISTURE
IS ACROSS THE EASTERN CARIBBEAN AS MOIST SOUTHWESTERLY FLOW
ALOFT SPREADS OVER THIS AREA. ISOLATED SHOWERS ARE EMBEDDED
WITHIN THE EASTERLY TRADEWIND FLOW EAST OF 71W. WINDS OF 15-20
KT ARE ACROSS MUCH OF THE EASTERN AND CENTRAL PORTIONS OF THE
BASIN WITH MORE NORTHERLY AND LIGHTER WINDS ACROSS THE NW
CORNER. THE SURFACE TROUGH IS EXPECTED TO DRIFT NW OVER THE NEXT
COUPLE OF DAYS BEFORE DISSIPATING OVER THE YUCATAN PENINSULA.

THE ATLANTIC OCEAN...
A SHORTWAVE UPPER TROUGH IN THE NW ATLC IS SUPPORTING A
DISSIPATING STATIONARY FRONT THAT EXTENDS ALONG 32N77W TO
29N80W. ISOLATED SHOWERS ARE WITHIN 30 NM OF THE AXIS. THE
REMAINDER OF THE WEST ATLC IS DOMINATED BY BROAD SURFACE RIDGING
AROUND A 1028 MB HIGH NEAR 35N61W. THE RIDGE IS SUPPORTED BY A
BROAD UPPER RIDGE ALONG 64W. HOWEVER...AN UPPER LEVEL TROUGH IN
THE CENTRAL CARIBBEAN CONTINUES INTO THE SW NORTH ATLC AND
SUPPORTS AN AREA OF SCATTERED SHOWERS FROM 20N-23N BETWEEN
58W-63W. FARTHER EAST...A LARGE UPPER LEVEL LOW COVERS THE N
CENTRAL ATLC NEAR 47N39W. IT SUPPORTS TWO COLD FRONTS THAT
CONTINUE INTO THE DISCUSSION AREA. THE FIRST IS ALONG 32N28W TO
17N42W WITH ISOLATED SHOWERS WITHIN 30 NM EITHER SIDE OF THE
AXIS. A SURFACE TROUGH IS SW OF THE FRONT ALONG 15N49W TO
10N53W. POSSIBLE ISOLATED SHOWERS ARE WITHIN 60 NM OF THE AXIS.
THE SECOND FRONT ENTERS THE AREA NEAR 32N36W TO 27N54W. ISOLATED
SHOWERS ARE ALSO WITHIN 30 NM EITHER SIDE OF THIS FRONT. BROAD
UPPER LEVEL RIDGING COVERS THE TROPICAL ATLC AS WELL AS THE FAR
EASTERN ATLC SUPPORTING A 1026 MB HIGH NEAR 32N18W...WHICH IS
PROVIDING SURFACE RIDGING AND FAIR CONDITIONS ACROSS THE
EASTERN ATLC.

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

$$
WALTON




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