[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 012338
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN NOV 01 2009

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...
A 998 MB LOW IS CENTERED NEAR 32N55W WITH A DISSIPATING
STATIONARY FRONT EXTEND S ALONG 33N49W 26N50W 19N61W TO 23N74W.
THE UPPER LEVEL SUPPORT FOR THIS SYSTEM IS A LARGE UPPER LOW
CENTERED NEAR 33N57W. INSTABILITY AND LIFT ASSOCIATED WITH THE
SYSTEM IS GENERATING DISORGANIZED SCATTERED MODERATE CONVECTION
WITHIN 75/90 NM OF LINE FROM 32N59W TO 35N50W. THE SURFACE LOW
HAS A HIGH CHANCE...GREATER THAN 50 PERCENT...OF BECOMING A
SUBTROPICAL OR TROPICAL CYCLONE OVER THE NEXT COUPLE OF DAYS AS
IT MOVES NW THEN NORTHWARD.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 53W S OF 17N MOVING W NEAR 20 KT. WAVE IS
EMBEDDED WITHIN A BROAD AREA OF DEEP LAYERED MOISTURE THAT IS
BEING DRAWN N INTO THE CENTRAL ATLC LOW PRESSURE SYSTEM NEAR
32N55W AND THE ASSOCIATED WEAKENING FRONTAL BOUNDARY. LOW LEVEL
CONVERGENCE NEAR THE WAVE AXIS COUPLED WITH UPPER LEVEL
DIFFLUENCE IS GENERATING SCATTERED MODERATE/ISOLATED STRONG
CONVECTION FROM 13N-17N BETWEEN 48W-52W.

TROPICAL WAVE IS ALONG 71W S OF 15N MOVING W NEAR 15 KT. WAVE
REMAINS AND IS MOSTLY INLAND OVER SOUTH AMERICA. A SLIGHT
MOISTURE MAXIMUM IS NOTED ON TOTAL PRECIPITABLE WATER IMAGERY S
OF 14N BETWEEN 68W-74W. ISOLATED SHOWERS ARE FROM 13N-15N
BETWEEN 68W-72W.

TROPICAL WAVE IS ALONG 90W S OF 16N MOVING W 10-15 KT. WAVE IS
NOW COMPLETELY INLAND OVER CENTRAL AMERICA AND IN THE E PACIFIC
REGION.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N13W 7N26W 7N40W 10N50W THEN
ACROSS THE N PORTION OF SOUTH AMERICA ALONG 11N72W THROUGH THE
SW CARIBBEAN OVER COSTA RICA NEAR 10N84W INTO THE E PACIFIC
REGION. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 100 NM OF
LINE FROM 7N36W TO 13N48W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 6N-11N BETWEEN 16W-20W AND FROM 7N-9N BETWEEN
20W-24W.

...DISCUSSION...

GULF OF MEXICO...
A STATIONARY FRONT REMAINS OVER THE E GULF EXTENDING ACROSS THE
FLORIDA PENINSULA NEAR DAYTONA BEACH TO JUST S OF TAMPA INTO THE
GULF ALONG 24N85W 21N92W TO THE COAST OF S MEXICO NEAR 18N93W.
THE FRONT IS SUPPORTED ALOFT BY A BROAD LOW AMPLITUDE UPPER
TROUGH ACROSS THE E US AND NW GULF. LOW LEVEL CONVERGENCE NEAR
AND ALONG THE FRONT IS GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS MAINLY OVER THE SW GULF WITHIN 120 NM
EITHER SIDE OF THE FRONT W OF 88W. STRONGER ACTIVITY IS
OCCURRING INLAND OVER THE YUCATAN PENINSULA. MODERATE/STRONG N
TO NE WINDS COVER THE GULF N OF THE FRONT BUT WILL BE
DIMINISHING LATER TONIGHT. DRY STABLE AIR IS BEING USHERED IN
WITH A SURFACE RIDGE THAT IS BUILDING IN BEHIND THE FRONT
ANCHORED BY A 1024 MB HIGH CENTERED OVER S ARKANSAS. THE FRONT
WILL BECOME DIFFUSE ON MONDAY AS A REINFORCING SURGE WILL
INCREASE NE WINDS OVER SW GULF ON TUE.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE EXTENDS FROM GUATEMALA ACROSS THE YUCATAN
PENINSULA INCLUDING PORTIONS OF CENTRAL AMERICA. DIFFLUENCE
ALOFT IS GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
OVER THE YUCATAN PENINSULA AND IN THE GULF OF HONDURAS S OF 18N
W OF 85W AND OVER MUCH OF CENTRAL AMERICA SW OF A LINE FROM
NICARAGUA NEAR 15N84W TO NW COLOMBIA NEAR 11N75W. THE REMAINDER
UPPER LEVEL PATTERN ACROSS THE CARIBBEAN BASIN CONSISTS OF SHEAR
AXIS THAT EXTENDS FROM THE LEEWARD ISLANDS NEAR GUADELOUPE OVER
JAMAICA THEN W CUBA NEAR 22N82W. DRY STABLE AIR AND THUS CLEAR
SKIES ARE OVER THE N CARIBBEAN FROM THE LEEWARD ISLANDS NEAR
MARTINIQUE ALONG 15N80W TO THE YUCATAN CHANNEL NEAR 22N86W.
HOWEVER...A FEW ISOLATED LOW LEVEL SHOWERS LINGER ACROSS THE
AREA.

ATLANTIC OCEAN...
A COLD FRONT EXTENDS ACROSS THE FAR W ATLC FROM A 1012 MB LOW
ALONG THE COAST OF NORTH CAROLINA THROUGH 32N78W ACROSS THE
FLORIDA PENINSULA NEAR DAYTONA BEACH AND INTO THE GULF OF MEXICO
AS A STATIONARY FRONT. POSSIBLE ISOLATED SHOWERS ARE WITHIN 60
NM EITHER SIDE OF THE FRONT. SHIFTING EASTWARD...THE PRIMARY
FOCUS IN THE ATLC WATERS OVERALL IS A 998 MB LOW IN THE SPECIAL
FEATURES SECTION ABOVE. A LARGE UPPER LEVEL RIDGE IS TO THE W
ANCHORED OVER THE W ATLC NEAR 26N75W AND A SECOND UPPER LEVEL
RIDGE TO THE E ANCHORED OVER WESTERN SAHARA NEAR 22N15W. THIS
SCENARIO IS ADVECTING TROPICAL MOISTURE NE AND GENERATING A
LARGE AREA OF NUMEROUS SHOWERS AND SCATTERED TO ISOLATED
THUNDERSTORMS WITHIN 200 NM OF A LINE FROM 17N52W 25N47W TO
33N47W WHICH IS E OF THE FRONT. A SURFACE RIDGE IS OVER THE E
ATLC ANCHORED BY A 1035 MB HIGH JUST NW OF THE AZORES.

$$
WALLACE



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