[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182341
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST FRI NOV 18 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM 12N53W TO 19N52W AND HAS REMAINED
NEARLY STATIONARY OVER THE LAST 24 HOURS. THE ASSOCIATED ENERGY
HAS CONTINUED TO BE ABSORBED BY AN ELONGATED UPPER LEVEL LOW
WITH MEAN CENTER NEAR 25N55W AND STRONG TROUGH AXIS EXTENDING
S-SW INTO THE SE CARIBBEAN SEA NEAR 14N65W. UPPER LEVEL
DIFFLUENCE REMAINS STRONG EAST OF THE WAVE AXIS WITH SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION FROM NORTH OF THE ITCZ
ALONG 07N TO 21N BETWEEN 41W-52W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N17W TO
11N17W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
09N17W TO 05N30W TO 08N46W. SCATTERED MODERATE CONVECTION IS
FROM 03N-08N BETWEEN 17W-44W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES MOSTLY WEST-SOUTHWESTERLY UPPER
LEVEL FLOW IN DRY AIR ALOFT IS IN CONTROL ACROSS THE GULF BASIN
THIS EVENING. THE ONLY SIGNIFICANT AREA OF MOISTURE NOTED IS
OVER THE SW GULF S OF 22N FOCUSED ALONG A SURFACE TROUGH
ANALYZED FROM 22N97W TO 18N93W. SCATTERED SHOWERS ARE OCCURRING
S OF 22N BETWEEN 92W-98W. THE REMAINDER OF THE GULF IS UNDER THE
INFLUENCE OF A SURFACE RIDGE WITH AXIS EXTENDING SW FROM A 1033
MB HIGH CENTERED OVER EASTERN VIRGINIA. THE RIDGE AXIS EXTENDS
OVER THE NW GULF WATERS AND NORTHEASTERN MEXICO TO 25N100W.
BETWEEN THIS RIDGE AND LOWER PRESSURE OVER THE CARIBBEAN SEA...A
DISSIPATING STATIONARY FRONT EXTENDS FROM THE SW NORTH ATLC
THROUGH THE FLORIDA STRAITS AND SE GULF WATERS TO THE YUCATAN
PENINSULA NEAR 21N88W. WHILE MOST OF THE FRONT OVER THE SE GULF
WATERS LACKS ANY SIGNIFICANT MOISTURE OR STRONG LIFT TO SUSTAIN
CONTINUED SHOWER ACTIVITY...NE TO E WINDS REMAIN STRONG OVER THE
W ATLC AND FLORIDA PENINSULA INTO THE FAR EASTERN GULF WITH
LOW-TOPPED WIDELY SCATTERED SHOWERS RIDING THE EASTERLY WINDS
AND OCCURRING FROM 25N-29N E OF 87W. THE RIDGE IS FORECAST TO
REMAIN ACROSS THE GULF WITH MOSTLY E TO SE WINDS IN THE 15 TO 20
KT RANGE EXPECTED THROUGH THE DURATION OF THE WEEKEND INTO
MONDAY.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE AXIS EXTENDS FROM THE YUCATAN PENINSULA
ALONG 20N WITH DRY AIR ALOFT NOTED N OF 14N E OF 88W. MOST OF
THIS AREA IS UNDER THE INFLUENCE OF NORTHEASTERLY WINDS AT THE
SURFACE WITH ISOLATED SHOWERS MOVING GENERALLY WESTWARD ON THE
TRADE WINDS. THE AREA OF CONSIDERABLE LOWER-LEVEL MOISTURE IS
NOTED IN THE SW CARIBBEAN S OF 13N BETWEEN 72W-84W FOCUSED ALONG
THE MONSOON TROUGH EXTENDING FROM THE E PACIFIC REGION ALONG
10N/11N TO NORTHERN COLOMBIA. AS A FRONTAL BOUNDARY LOCATED OVER
THE SW NORTH ATLC CONTINUES TO DRIFT SOUTH AND EASTWARD OVER THE
NEXT FEW DAYS WHILE DISSIPATING...NE WINDS ARE EXPECTED TO
INCREASE SATURDAY AND SUNDAY ACROSS THE NORTH-CENTRAL CARIBBEAN
WITH STRONGER WINDS ANTICIPATED THROUGH THE MONA AND WINDWARD
PASSAGES.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH AXIS EXTENDS FROM OFFSHORE OF NOVA SCOTIA
TO THE DISCUSSION BORDER NEAR 31N75W AND SUPPORTS A COLD FRONT
ANALYZED FROM 32N62W TO 28N70W BECOMING STATIONARY TO THE
CENTRAL BAHAMAS NEAR 25N77W AND INTO THE SE GULF OF MEXICO
THROUGH THE STRAITS OF FLORIDA. ISOLATED SHOWERS ARE OCCURRING
WITHIN 60 NM EITHER SIDE OF THE COLD FRONT AND WITHIN 180 NM
NORTH OF THE STATIONARY FRONT...INCLUDING MUCH OF THE CENTRAL
AND SOUTHERN FLORIDA PENINSULA THIS EVENING. AN EARLIER ASCAT
PASS FROM 18/1520 UTC SHOWED STRONG NE WINDS IN THE RANGE OF 20
TO 25 KT EXTENDING NORTH OF THE FRONT AND BEYOND 32N. FARTHER
EAST...AN ELONGATED UPPER LEVEL LOW IS CENTERED NEAR 25N55W AND
IS SUPPORTING A 1013 MB SURFACE LOW CENTERED NEAR 26N55W WITH A
SURFACE TROUGH ANALYZED THROUGH THE LOW FROM 31N54W TO 22N56W.
LOW-LEVEL CONVERGENCE EAST OF THE SURFACE TROUGH AND STRONG
UPPER LEVEL DIFFLUENCE EAST OF THE UPPER LEVEL TROUGH AXIS IS
GENERATING AN AREA OF SCATTERED MODERATE CONVECTION FROM 21N33N
BETWEEN 45W-53W. THIS AREA OF CONVECTION IS ADJACENT TO
CONVECTION ASSOCIATED WITH THE ABSORBED TROPICAL WAVE ALONG 53W
MENTIONED ABOVE. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED
NEAR 34N37W. NE TO E WINDS IN THE RANGE OF 15 TO 20 KT CONTINUE
ON THE SOUTHEASTERN PERIPHERY OF THE RIDGE S OF 32N E OF 35W.

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

$$
HUFFMAN




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