[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171737
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED NOV 17 2010

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N14W 9N20W 8N30W 6N38W 5N50W.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 60
NM OF THE ITCZ BETWEEN 34W-37W. CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE WITHIN 120/150 NM EITHER SIDE OF
THE ITCZ BETWEEN 26W-39W AND WITHIN 120 NM N OF THE ITCZ BETWEEN
44W-49W. SMALL CLUSTERS OF SIMILAR CONVECTION ARE FROM 3N-6N
BETWEEN 10W-16W.

...DISCUSSION...

GULF OF MEXICO...
THE BROAD UPPER TROUGH CONTINUES TO MOVE NE WHILE THE UPPER
RIDGE ANCHORED IN THE CARIBBEAN IS LEAVING THE GULF WATERS WITH
UPPER LEVEL WSW FLOW. THE TAIL END OF THE COLD FRONT IS MOVING
ACROSS THE GULF FROM TAMPA BAY NEAR 27N83W EXTENDING TO 24N88W
BECOMING STATIONARY AND DISSIPATING FROM 22N92W TO THE COAST OF
MEXICO NEAR VERA CRUZ. NOT MUCH SHOWER ACTIVITY IS ASSOCIATED
WITH THIS FRONT. A SURFACE RIDGE IS BUILDING BEHIND THE FRONT
ANCHORED BY WEAK SURFACE HIGHS OVER ALABAMA CAUSING MAINLY
RETURN FLOW OVER THE NORTHERN GULF BEHIND THE FRONT. MODERATE/
STRONG SUBSIDENCE AND DRY STABLE AIR ALOFT COVERS THE GULF
GIVING THE ENTIRE AREA FAIR WEATHER THIS AFTERNOON. THIS FRONT
WILL MOVE SE OF THE AREA BY EARLY THURSDAY AS A SECOND FRONT IS
EXPECTED TO MOVE INTO THE NW GULF LATER TONIGHT.

CARIBBEAN SEA...
A SURFACE TROUGH EXTENDS FROM 19N83W THROUGH AN 1012 MB LOW NEAR
15N81W TO 13N79W GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS WITHIN 120 NM NE OF THE SURFACE TROUGH N
OF THE LOW CENTER. A BROAD UPPER RIDGE COVERS THE ENTIRE
CARIBBEAN ANCHORED BETWEEN HISPANIOLA AND JAMAICA NEAR 17N75W
AND EXTENDS INTO THE W ATLC PROVIDING DIFFLUENCE ALOFT TO
ENHANCE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120/150
NM OF A LINE FROM 19N78W TO THE COAST OF COLOMBIA NEAR 11N74W. E
CARIBBEAN IS UNDER STRONG SUBSIDENCE AND DRY STABLE AIR E OF 72W
GIVING THE AREA MOSTLY CLEAR SKIES. A SURFACE TROUGH E OF THE
LESSER ANTILLES IS GENERATING LOW LEVEL SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS OVER THE SE CARIBBEAN SE OF A
LINE FROM GUADALUPE TO THE ABC ISLANDS. EXPECT SHOWERS/
THUNDERSTORMS ASSOCIATED WITH THE LOW/TROUGH TO CONTINUE OVER
THE CENTRAL CARIBBEAN FOR THE NEXT DAY OR SO AND AN INCREASE IN
SHOWERS/THUNDERSTORMS OVER THE E CARIBBEAN AS THE SURFACE TROUGH
MOVES ACROSS THE LESSER ANTILLES.

ATLANTIC OCEAN...
AN UPPER TROUGH HAS MOVED INTO THE NW ATLANTIC SUPPORTING A COLD
FRONT THAT ENTERS THE REGION NEAR 32N78W ACROSS FLORIDA INTO THE
GULF OF MEXICO NEAR DAYTONA BEACH. THE UPPER RIDGE ANCHORED IN
THE CARIBBEAN COVERS THE W ATLC BETWEEN 60W-70W WITH A SURFACE
RIDGE N OF 30N BETWEEN 55W-70W. STRONG SUBSIDENCE AND DRY STABLE
AIR ALOFT COVER THE W ATLC W OF 50W GIVING THE AREA FAIR WEATHER
THIS AFTERNOON. AN ELONGATED DEEP LAYERED LOW IS OVER THE
CENTRAL ATLC WITH THE UPPER LOW CENTERED N OF THE REGION AND THE
UPPER TROUGH EXTENDING S TO 16N BETWEEN 40W-55W. THIS UPPER
SYSTEM IS SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM A 1011
MB SURFACE LOW NEAR 29N50W ALONG 25N52W TO 24N57W WITH SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 150/200 NM OF
LINE FROM 21N47W TO BEYOND 32N41W. A BROAD UPPER RIDGE COVERS
THE E ATLC ENHANCING THE ACTIVITY DESCRIBED ABOVE. A SURFACE
RIDGE COVERS THE E ATLC N OF 18N E OF 40W ANCHORED BY A WEAK
1022 MB HIGH W OF THE CANARY ISLANDS NEAR 29N23W. A SURFACE
TROUGH IS IN THE W TROPICAL ATLC EXTENDING FROM 17N56W TO INLAND
OVER SOUTH AMERICA NEAR 7N59W GENERATING SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS S OF 13N W OF 53W ACROSS THE
LESSER ANTILLES INTO THE SE CARIBBEAN.

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

$$
SMM/PAW





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