[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111728
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI JAN 11 2013

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
1645 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH THE SOUTHERN COAST OF LIBERIA
FROM 5N9W TO 5N16W WHERE IT TRANSITIONS INTO ITCZ AND CONTINUES
ALONG 5N30W 4N40W EQ48W. ISOLATED MODERATE CONVECTION IS FROM
1N-5N BETWEEN 25W-30W. SIMILAR ACTIVITY IS FROM EQ-3N BETWEEN
43W-49W.

...DISCUSSION...

GULF OF MEXICO...
THE STATIONARY FRONT THAT HAS BEEN IMPACTING THE NW GULF OF
MEXICO THE PAST COUPLE OF DAYS IS FINALLY BEGINNING TO WEAKEN
SOME. A STATIONARY BOUNDARY STILL EXISTS FROM SE LOUISIANA NEAR
29N91W TO 26N94W WHERE IT THEN BEGINS TO DISSIPATE TO 21N95W.
SCATTERED SHOWERS STILL REMAIN WITHIN 30 NM EITHER SIDE OF THE
AXIS WITH POSSIBLE SHOWERS NEAR THE DISSIPATING PORTION OF THE
FRONT. IN THE UPPER LEVELS...A NARROW UPPER TROUGH EXTENDS FROM
THE FLORIDA PANHANDLE TO THE YUCATAN PENINSULA. DUE TO THE FACT
THAT THE UPPER TROUGH IS NOW EAST OF THE LOW-LEVEL
BOUNDARY...THE FRONT WILL QUICKLY WEAKEN. UPPER LEVEL RIDGING
DOMINATES THE REMAINDER OF THE BASIN ACCOMPANIED BY DRY AIR
ALOFT...WHICH IS HELPING MAINTAIN FAIR CONDITIONS ACROSS THE
BASIN BESIDES NEAR THE FRONT. WIND SPEEDS STILL REMAIN IN THE
RANGE OF 15-20 KT EAST OF THE FRONT WITH LIGHTER WINDS WEST OF
THE AXIS. SURFACE RIDGING IS EXPECTED TO BUILD ACROSS THE BASIN
BEFORE THE NEXT FRONT MOVES INTO THE NW CARIBBEAN ON SUNDAY.

CARIBBEAN SEA...
THE CARIBBEAN IS EXPERIENCING MOSTLY FAIR WEATHER WITH SURFACE
RIDGING TO THE NORTH SUPPORTED BY AN UPPER LEVEL RIDGE COVERING
THE WESTERN HALF OF THE BASIN ACCOMPANIED BY DRY AIR. A BROAD
UPPER TROUGH IS ACROSS THE EASTERN CARIBBEAN WITH AN AREA OF
STRONG SUBSIDENCE NEAR THE COAST OF COLOMBIA. THIS...ALONG WITH
A TIGHT PRESSURE GRADIENT DUE TO THE SURFACE RIDGE TO THE NORTH
IS HELPING SUPPORT GALE FORCE WINDS NORTH OF COLOMBIA. MAINLY
20-25 KT TRADEWIND FLOW IS ACROSS THE REMAINDER OF THE BASIN.
PATCHES OF LOW-LEVEL CLOUDS WITH ISOLATED SHOWERS ARE MOVING
QUICKLY ACROSS THE AREA MAINLY IN THE EASTERN AND CENTRAL
PORTIONS ESPECIALLY ALONG THE COAST OF VENEZUELA. THE GALE FORCE
WINDS ARE EXPECTED TO REMAIN ANOTHER SIX HOURS BEFORE
DIMINISHING BELOW GALE FORCE. LITTLE CHANGE IS EXPECTED
ELSEWHERE.

ATLANTIC OCEAN...
SURFACE RIDGING COVERS THE WEST ATLC PROVIDING MOSTLY FAIR
CONDITIONS. THE RIDGE IS SUPPORTED BY A BROAD UPPER LEVEL RIDGE
COVERING THE EASTERN CONUS AND WEST ATLC. BROAD UPPER TROUGHING
AROUND AN UPPER LEVEL LOW WELL NORTH OF THE AREA NEAR 42N50W
COVERS THE CENTRAL ATLC SUPPORTING A COLD FRONT THAT HAS PUSHED
INTO THE AREA ALONG 32N47W 28N53W 27N61W. POSSIBLE ISOLATED
SHOWERS ARE ALONG THE FRONT. GALE FORCE WINDS ARE EXPECTED
BEHIND THIS FRONT BY 1800 UTC TODAY NORTH OF 29N WEST OF THE
FRONT TO 55W. A WEAK SURFACE TROUGH...REMNANTS OF AN OLD FRONTAL
BOUNDARY...IS SOUTH OF THE COLD FRONT FROM 26N46W TO 21N51W.
ISOLATED SHOWERS ARE WITHIN 30 NM EITHER SIDE OF THE AXIS. THE
REMAINDER OF THE EASTERN ATLC IS DOMINATED BY SURFACE RIDGING
AROUND A 1026 MB HIGH NEAR 35N14W. THE RIDGE IS SUPPORTED BY AN
UPPER LEVEL RIDGE THAT IS NORTH OF THE AREA AND EAST OF THE
BROAD UPPER LEVEL LOW. ACROSS THE TROPICS...MAINLY ZONAL
WESTERLY FLOW IS ALOFT.

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

$$
WALTON





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