[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 042351
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED JAN 04 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
2335 UTC.

...ITCZ/MONSOON TROUGH...

MOST OF THE MONSOON TROUGH REMAINS INLAND OVER AFRICA. ONLY A
SMALL PORTION OF IT EXTENDS FROM THE COAST OF LIBERIA NEAR
6N11W TO ABOUT 4N17W. THE ITCZ EXTENDS WESTWARD FROM THIS POINT
ALONG 3N25W 4N39W TO THE COAST OF BRAZIL NEAR EQ49W. SCATTERED
WEAK TO ISOLATED MODERATE CONVECTION IS WITHIN 130 NM ON EITHER
SIDE OF THE ITCZ AXIS BETWEEN 25W-45W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY SHOWS WESTERLY FLOW CARRYING DRY AIR AND
STRONG SUBSIDENCE ALOFT ACROSS THE GULF THIS EVENING. THIS UPPER
LEVEL ENVIRONMENT SUPPORTS A PAIR OF 1028 MB HIGHS NEAR 28N83W
AND 26N91W. MARINE OBSERVATIONS INDICATE A LIGHT AND VARIABLE
WINDS IN THE VICINITY OF THE SURFACE HIGHS...WHILE ANTICYCLONIC
FLOW ELSEWHERE ACROSS THE AREA. THE COOLER AIRMASS MOVING OVER
RELATIVELY WARM WATERS IS GENERATING A BROAD AREA OF LOW LEVEL
STRATOCUMULUS CLOUDS SW OF A LINE EXTENDING FROM 29N95W TO
24N81W. COMPUTER MODELS ARE IN GOOD AGREEMENT KEEPING RIDGING
CONDITIONS ACROSS THE DISCUSSION AREA THROUGH SATURDAY...AS THE
NEXT COLD FRONT ENTERS THE NW BASIN ON SUNDAY.

CARIBBEAN SEA...
THE SRN EXTENSION OF A COLD FRONT MOVING ACROSS THE ATLC EXTENDS
SW INTO THE CENTRAL CARIBBEAN AS A SHEAR LINE THROUGH THE MONA
PASSAGE ALONG 18N68W TO THE COAST OF PANAMA NEAR 9N82W. AN
EARLIER ASCAT PASS INDICATED NORTHERLY WINDS 20-25 KT AND
EASTERLY WINDS 10-15 KT CONVERGING ALONG THE SHEAR LINE...
GENERATING SCATTERED WEAK SHOWERS WITHIN 90 NM ON EITHER SIDE OF
THE LINE. A COOLER AIRMASS REMAINS OVER THE NW CARIBBEAN W OF
THE SHEAR LINE WITH LOW LEVEL STRATOCUMULUS ROAMING THIS REGION.
A FEW CLUSTERS OF WEAK SCATTERED SHOWERS ARE E OF THE LINE
EMBEDDED IN THE EASTERLY FLOW. IN THE UPPER LEVELS...DRY AIR
ALOFT AND STRONG SUBSIDENCE REMAINS ELSEWHERE ACROSS THE BASIN.
THE SHEAR LINE IS EXPECTED TO CONTINUE TO WEAKEN OVER THE NEXT
24 HRS.

ATLANTIC OCEAN...
AN UPPER LEVEL LONGWAVE/TROUGH MOVES ACROSS THE N CENTRAL ATLC
SUPPORTING A COLD FRONT THAT ENTERS THE REGION ALONG 32N55W
EXTENDING S-SW ALONG 25N61 INTO THE CARIBBEAN SEA ALONG THE MONA
PASSAGE. THE COMBINATION OF LOW LEVEL CONVERGENCE OF NW AND
SOUTHERLY WINDS AND UPPER LEVEL DIFFLUENCE ALONG THE BOUNDARY IS
GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN
100 NM E OF IT N OF 25N. AS THE MAIN UPPER LEVEL SUPPORT FOR
THIS FRONT CONTINUES TO QUICKLY MOVE NE INTO THE POLAR
REGIONS...COMPUTER MODELS SUGGEST THE FRONT WILL BECOME SLOWER
TO NEARLY STATIONARY OVER THE NEXT 24 HRS WITH SOME LIMITED
CONVECTION REMAINING ALONG THE BOUNDARY. OTHERWISE...SURFACE
RIDGING AROUND A STRONG 1039 MB HIGH CENTERED OFF THE COAST OF
PORTUGAL NEAR 41N17W IS KEEPING FAIR WEATHER CONDITIONS ACROSS
THE REMAINDER OF THE DISCUSSION AREA THIS EVENING.

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

$$

GARCIA




This weather bulletin was brought to you by:
www.nashvilleweather.net