[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280553
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU OCT 28 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...
A NEAR STATIONARY 1010 MB SURFACE LOW IS CENTERED OVER 1000 NM
NW OF THE CAPE VERDE ISLANDS NEAR 27N41W WITH A SURFACE TROUGH
EXTENDING NNE TO BEYOND 32N37W. SCATTERED SHOWERS WITH POSSIBLE
ISOLATED THUNDERSTORMS AND GALE FORCE WINDS ARE E OF THE
LOW/TROUGH TO 35W BETWEEN 25N-30N. ORGANIZATION HAS CHANGED
LITTLE OVER THE PAST FEW HOURS. ALTHOUGH UPPER LEVEL WINDS ARE
ONLY MARGINALLY CONDUCIVE FOR DEVELOPMENT...ONLY A SMALL INCREASE
IN ORGANIZATION WOULD RESULT IN THE FORMATION OF A TROPICAL
STORM. THERE IS A MEDIUM CHANCE OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

A BROAD AREA OF CYCLONIC CURVATURE IS ABOUT 500 NM NE OF THE
LEEWARD/VIRGIN ISLANDS WITH A SURFACE TROUGH ANALYZED FROM
27N53W TO 20N57W SUPPORTED BY AN UPPER LOW NEAR 23N62W AND
GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
WITHIN 150 NM OF LINE FROM 21N48W TO 26N55W AND SCATTERED
SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM OF
LINE FROM 24N59W TO 29N55W. SHOWER/THUNDERSTORM ACTIVITY HAS
BEEN INCREASING DURING THE PAST FEW HOURS AND ENVIRONMENTAL
CONDITIONS ARE BECOMING CONDUCIVE FOR THE DEVELOPMENT OF A
TROPICAL OR SUBTROPICAL DEPRESSION DURING THE NEXT COUPLE OF
DAYS. THERE IS A HIGH CHANCE OF THIS SYSTEM BECOMING A
SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT
MOVES W NEAR 15 KT.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 13N42W THROUGH A 1008 MB LOW NEAR
6N45W TO 2N45W MOVING W 15-20 KT. WAVE REMAINS EMBEDDED WITHIN A
BROAD MID LEVEL CYCLONIC ROTATION CENTERED JUST TO THE E OF THE
LOW CENTER. SCATTERED TO NUMEROUS STRONG CONVECTION IS FROM
8N-12N BETWEEN 41W-49W. CLUSTERS OF SCATTERED MODERATE/STRONG
CONVECTION COVERS THE REMAINDER OF THE AREA FROM 3N-14N BETWEEN
40W-52W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N16W 7N27W 8N38W. CLUSTERS OF
SCATTERED MODERATE/STRONG CONVECTION ARE FROM 5N-8N BETWEEN
9W-15W INCLUDING THE COAST OF SW AFRICA. SMALL CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 150 NM
OF LINE FROM 5N17W TO 8N35W.

...DISCUSSION...

GULF OF MEXICO...
THE LARGE UPPER TROUGH REMAINS OVER THE U.S. BUT HAS SHIFTED
NORTHWARD KEEPING THE ASSOCIATED FRONTAL BOUNDARY WELL INLAND.
AN UPPER RIDGE HAS SET UP OVER THE GULF WATERS ANCHORED NEAR
TALLAHASSEE FLORIDA EXTENDING A RIDGE AXIS W TO NEAR BROWNSVILLE
TEXAS. A SURFACE RIDGE ANCHORED IN THE W ATLC EXTENDS ACROSS THE
FLORIDA PENINSULA TO OVER THE E GULF TO 90W. A PERSISTENT UPPER
RIDGE REMAINS OVER THE SW GULF ANCHORED OVER S MEXICO COVERING
THE GULF WATERS S OF 24N W OF 87W. WATER VAPOR IMAGERY CONTINUES
TO INDICATE MODERATE/STRONG SUBSIDENCE AND DRY AIR ALOFT
DOMINATES THE GULF GIVING THE GULF MOSTLY CLEAR SKIES AGAIN
TONIGHT WITH THE EXCEPTION OF SOME ISOLATED LOW LEVEL SHOWERS
WITHIN 60 NM OF LINE FROM 27N90W TO THE YUCATAN CHANNEL/W CUBA
NEAR 22N85W.

CARIBBEAN SEA...
THE BROAD UPPER RIDGE THAT HAS DOMINATED THE CARIBBEAN OVER THE
PAST SEVERAL DAYS HAS SHIFTED W NOW ANCHORED OVER S MEXICO
COVERING ONLY THE FAR W CARIBBEAN W OF 75W PROVIDING DIFFLUENCE
ALOFT AND COUPLED WITH ANY LINGERING MOISTURE OVER THE SW
CARIBBEAN CONTINUES TO GENERATE CLUSTERS OF SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS S OF A LINE FROM COLOMBIA NEAR 11N73W TO
NE NICARAGUA NEAR 14N84W. A LARGE UPPER LOW OVER THE W/CENTRAL
ATLC COVERS THE REMAINDER OF THE CARIBBEAN. WATER VAPOR IMAGERY
INDICATES MODERATE SUBSIDENCE AND DRY AIR ALOFT IS MAINTAINED
ACROSS THE CENTRAL CARIBBEAN FROM THE LESSER ANTILLES TO THE
YUCATAN PENINSULA GIVING THE REMAINDER OF THE BASIN FAIR WEATHER
AGAIN TONIGHT WITH SOME POSSIBLE ISOLATED LOW LEVEL SHOWERS
MOVING ACROSS THE E CARIBBEAN E OF 75W INCLUDING THE LESSER
ANTILLES.

ATLANTIC OCEAN...
THE UPPER RIDGE ANCHORED OVER THE THE FLORIDA PANHANDLE COVERING
THE N GULF OF MEXICO EXTENDS OVER THE FAR W ATLC N OF 24N W OF
74W. A SURFACE RIDGE COVERS THE W ATLC EXTENDING W INTO THE E
GULF OF MEXICO ANCHORED BY A 1028 MB HIGH ABOUT 500 NM ENE OF
BERMUDA LEAVING THE W ATLC W OF 63W UNDER FAIR CONDITIONS AGAIN
TONIGHT. THE SHORTWAVE UPPER TROUGH HAS DEVELOPED INTO AN UPPER
LOW ROUGHLY CENTERED 23N62W AND COVERING THE CENTRAL/W ATLC AND
THE E CARIBBEAN BETWEEN 50W-74W ENHANCING THE ACTIVITY
ASSOCIATED WITH THE POSSIBLE SUBTROPICAL SYSTEM IN THE SPECIAL
FEATURES...SEE ABOVE. A VERY WEAK UPPER LOW IS IN THE E/CENTRAL
ATLC CENTERED ROUGHLY NEAR 27N39W SUPPORTING THE POSSIBLE
TROPICAL SYSTEM IN THE SPECIAL FEATURES...SEE ABOVE. A WEAKENING
SURFACE RIDGE CONTINUES TO DOMINATE THE FAR E ATLC N OF 25N E OF
30W ANCHORED BY A 1026 MB HIGH OFF THE COAST OF PORTUGAL.

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

$$
PAW




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