[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED NOV 23 2011

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 1735 UTC.

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

THE MONSOON TROUGH EXTENDS ACROSS WRN AFRICA THROUGH GUINEA
ENTERING THE ATLC WATERS ALONG 10N15W TO 9N20W. THE ITCZ AXIS
EXTENDS FROM 9N20W ALONG 5N30W TO 6N42W. A SURFACE TROUGH IS
ANALYZED W OF THE ITCZ 13N44W TO 5N47W WITH ISOLATED WEAK
CONVECTION WITHIN 30 NM EITHER SIDE OF THE TROUGH AXIS.
SCATTERED MODERATE CONVECTION IS WITHIN 100-150 NM EITHER SIDE
OF THE ITCZ. ANOTHER SURFACE TROUGH IS MOVING NEAR THE COASTAL
WATERS OF GUYANA...ANALYZED FROM 12N55W TO 8N59W. ISOLATED
MODERATE CONVECTION IS WELL REMOVED TO THE W OF THE AXIS
AFFECTING THE ISLAND OF ADJACENT WATERS OF TRINIDAD AND TOBAGO.

...DISCUSSION...

GULF OF MEXICO...
MOSTLY DRY WESTERLY ZONAL FLOW ALOFT IS OBSERVED ACROSS THE GULF
ON WATER VAPOR IMAGERY THIS AFTERNOON. HOWEVER...AN UPPER LEVEL
SHORTWAVE TROUGH MOVES ACROSS THE ERN CONUS REACHING DOWN TO THE
FAR NORTHERN GULF COAST WATERS SUPPORTING A COLD FRONT CURRENTLY
ANALYZED FROM THE NRN FLORIDA PENINSULA TO THE MEXICO COAST S OF
TAMPICO ALONG 30N83W 25N91W TO 20N97W. FROM SATELLITE VISIBLE
IMAGERY...A THIN CLOUD LINE DENOTES THE FRONTAL BOUNDARY WITH
VERY LIMITED CONVECTION S OF 27N. TO THE N OF 27N...DOPPLER
RADAR IMAGERY INDICATED HEAVY SHOWERS AND THUNDERSTORMS AHEAD OF
THE BOUNDARY WITHIN 100 NM HEADING INLAND INTO THE FLORINA
PENINSULA. MARINE OBSERVATIONS ACROSS THE AREA SHOW SURFACE SSW
FLOW UP TO 15 KT IS AHEAD OF THE FRONT...WHILE A NORTHERLY
COMPONENT UP TO 20 KT BEHIND THE FRONT. COMPUTER MODELS SUGGEST
THE FRONT WILL CONTINUE TO MOVE INTO THE WRN ATLC BASIN WHILE
THE SRN EXTENSION OF THE BOUNDARY BECOMES STATIONARY WITH SOME
WEAK TO MODERATE CONVECTION LINGERING OVER THE SRN AND SW GULF
WITHIN THE NEXT 24 HOURS.

CARIBBEAN SEA...
WATER VAPOR IMAGERY DISPLAYS A VERY DRY UPPER ATMOSPHERE W OF A
LINE EXTENDING FROM ERN HISPANIOLA NEAR 18N69W TO THE COAST OF
NICARAGUA NEAR 12N83W. THIS UPPER AIRMASS IS SUPPRESSING
CONVECTION IN THIS REGAIN. A BROAD SURFACE CYCLONIC WIND FIELD
IS TO THE E OF THIS LINE WITH PLENTY OF LOW-MID LEVEL MOISTURE
NOTICED ON TOTAL PRECIPITABLE WATER IMAGERY. THIS PATTERN IS
GENERATING A BROAD AREA OF CLUSTERS OF SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS S OF A LINE FROM 12N64W ALONG 17N72W TO
12N83W. A SURFACE TROUGH IS EMBEDDED IN THIS BROAD CYCLONIC WIND
FIELD...EXTENDING FROM NEAR 15N76W INTO THE MONSOONAL GYRE NEAR
11N78W. THE MONSOON TROUGH EXTENDS ACROSS CENTRAL AMERICA ALONG
COSTA RICA INTO NRN COLOMBIA. EXPECT THE SURFACE TROUGH TO
COMPLETELY BECOME EMBEDDED IN THE MONSOON GYRE WITHIN THE NEXT
24-36 HOURS.

ATLANTIC OCEAN...
A WEAKENING SURFACE RIDGE IS ACROSS THE WRN ATLC WATERS
PROVIDING FAIR WEATHER CONDITIONS TO MOST OF THIS REGION...AS AN
UPPER LEVEL SHORTWAVE/TROUGH MOVES OFF THE ERN CONUS SEABOARD
THIS AFTERNOON. PRE-FRONTAL SHOWERS ARE ALREADY SHOWING UP ON
DOPPLER RADAR IMAGERY MOVING ACROSS THE FLORIDA PENINSULA INTO
THE ATLC WATERS N OF 27N. FAR AHEAD ACROSS THE CENTRAL ATLC...A
BROAD UPPER TROUGH/OCCLUDED LOW MOVES ACROSS THIS REGION
REFLECTING A 1008 MB LOW CENTERED NEAR 32N37W. THIS LOW PRESSURE
SYSTEM IS MOVING NE OUT OF OUR DISCUSSION AREA. A COLD FRONT
EXTENDS S FROM THE OCCLUSION POINT N OF THE LOW INTO OUR AREA
ALONG 32N36W AND CONTINUES SW ALONG 25N38W TO 21N43W... BECOMING
A SURFACE TROUGH TO NEAR 17N48W. SCATTERED SHOWERS ARE WITHIN
150 NM AHEAD OF THE FRONT N OF 20N. A RECENT ASCAT PASS OVER
THIS SYSTEM REVEALED NEAR GALE FORCE WINDS WITHIN 270 NM SE AND
150 NM NW QUADRANT GENERATING SEAS 8 TO 13 FT. A SHARP UPPER
RIDGE COVERS THE ERN N ATLC WITH SURFACE RIDGING AXIS EXTENDING
INTO OUR REGION ALONG 32N21W TO 15N32W...KEEPING FAIR WEATHER
CONDITIONS ELSEWHERE E OF 30W. EXPECT THE COLD FRONT CURRENTLY
IN THE GULF OF MEXICO TO COMPLETELY MOVE INTO THE WRN ATLC WITH
CONVECTION IN 24 HOURS.

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

$$

GARCIA




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