[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 302334
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI OCT 30 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.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 37W S OF 15N MOVING W NEAR 10 KT. ENERGY
FROM THE NORTHERN PORTION OF THE WAVE HAS FRACTURED AND IS
ANALYZED AS A SURFACE TROUGH ALONG 37W FROM 16N-22N. SCATTERED
SHOWERS ARE WITHIN 90 NM OF THE SURFACE TROUGH. FARTHER SOUTH...
SCATTERED SHOWERS ARE WITHIN 200 NM EITHER SIDE OF THE WAVE AXIS
AND OCCURRING BENEATH A STRONGLY SHEARED MIDDLE TO UPPER LEVEL
ENVIRONMENT ACROSS THE TROPICAL ATLC.

TROPICAL WAVE IS ALONG 60W S OF 19N MOVING W NEAR 10 KT. THE
WAVE CORRESPONDS WELL AGAIN AN AREA OF MAXIMUM TOTAL
PRECIPITABLE WATER ACROSS THE FAR EASTERN CARIBBEAN...LESSER
ANTILLES AND FAR WESTERN REACHES OF THE TROPICAL NORTH ATLC
BETWEEN 55W-65W. SCATTERED SHOWERS AND ISOLATED MODERATE
CONVECTION ARE FROM 14N-18N BETWEEN 57W-65W.

TROPICAL WAVE IS ALONG 78W S OF 17N MOVING W NEAR 15 KT. THE
WAVE LIES BENEATH THE EASTERN INFLUENCE OF AN UPPER LEVEL LOW
CENTERED OVER EL-SALVADOR. THE WAVE COUPLED WITH UPPER LEVEL
DIFFLUENCE ACROSS THE WESTERN CARIBBEAN IS GENERATING SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 10N-17N BETWEEN
76W-81W.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N14W 7N24W 8N36W 10N38W
12N59W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM EITHER
SIDE OF A LINE FROM 4N18W TO 8N36W. SIMILAR CONVECTION IS FROM
6N-15N BETWEEN 45W-59W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC...A COLD FRONT EXTENDS FROM SE LOUISIANA NEAR
29N91W ALONG 25N94W TO VERACRUZ MEXICO AND INLAND ACROSS EASTERN
MEXICO ALONG THE FRONT RANGE OF THE SIERRA MADRE ORIENTAL
MOUNTAINS. A LINE OF SCATTERED TO NUMEROUS SHOWERS AND ISOLATED
TSTMS IS ASSOCIATED WITH THE FRONT AND WITHIN 60 NM EITHER SIDE
OF THE FRONT S OF 25N AND WITHIN 120 NM EITHER SIDE OF THE FRONT
N OF 25N. STRONG NLY WINDS UP TO 30 KT ARE FORECAST ACROSS
PORTIONS OF THE NW AND SW GULF WITH THE FRONTAL PASSAGE. THIS
FRONT IS SUPPORTED ALOFT BY A SHARP UPPER LEVEL TROUGH ENTERING
THE CENTRAL U.S. PLAINS AND PROVIDING MOIST SWLY DIVERGENT FLOW
ALOFT BETWEEN THE TROUGH AND AN UPPER LEVEL ANTICYCLONIC
CIRCULATION CENTERED OVER THE NE GULF NEAR 29N83W. ANOTHER
FRONTAL BOUNDARY IS PRIMARILY STATIONARY OVER THE FLORIDA
PENINSULA THIS EVENING FROM WEST PALM BEACH NW TO VALDOSTA
GEORGIA. OBSERVATIONS ACROSS FLORIDA THIS EVENING SHOW VERY
LITTLE TEMPERATURE OR DEWPOINT GRADIENT AND ANY ISOLATED SHOWERS
MOVING ONSHORE ALONG THE EASTERN PENINSULA COAST WILL CONTINUE
TO DISSIPATE OVER THE NEXT FEW HOURS. BETWEEN THE TWO FRONTS...
SE SURFACE FLOW IS NOTED IN EASTERN GULF OBSERVATIONS WITH
GENERALLY CLEAR SKIES.

CARIBBEAN SEA...
UPPER LEVEL DIFFLUENCE GENERATED BY AN UPPER LEVEL LOW CENTERED
OVER EL-SALVADOR NEAR 13N89W IS GENERATING SCATTERED SHOWERS AND
ISOLATED TSTMS OVER A LARGE PORTION OF THE WESTERN CARIBBEAN
WITHIN 150 NM EITHER SIDE OF A LINE FROM 11N77W TO 19N86W. A
TROPICAL WAVE ALONG 78W IS ALSO IMPACTING THIS AREA AND
PROVIDING ENHANCEMENT TO THE CONVECTIVE ACTIVITY OVER THE SW
CARIBBEAN. THE REMAINDER OF THE CARIBBEAN E OF 78W IS UNDER THE
INFLUENCE OF AN UPPER LEVEL TROUGH WITH AXIS THAT EXTENDS FROM
THE CENTRAL ATLC THROUGH PUERTO RICO...HISPANIOLA AND JAMAICA.
NLY UPPER LEVEL WINDS N OF 18N TURN TO A MORE WESTERLY COMPONENT
AS WATER VAPOR IMAGERY INDICATES MODERATE SUBSIDENCE AND DRY AIR
IN THE MIDDLE TO UPPER LEVELS OF THE ATMOSPHERE THIS EVENING.
HOWEVER...WITH THE APPROACH OF THE TROPICAL WAVE ALONG 60W...
INCREASED LOW-LEVEL MOISTURE IS NOTED ON SATELLITE IMAGERY AND A
FEW SCATTERED SHOWERS ARE OCCURRING OVER THE LEEWARD ISLANDS AND
ADJACENT COASTAL WATERS FROM 14N-18N BETWEEN 57W-65W.

ATLANTIC OCEAN...
A 998 MB LOW IS OVER THE CENTRAL ATLC CENTERED NEAR 31N47W. A
COLD FRONT EXTENDS SW FROM THE LOW ALONG 27N50W 24N70W TO THE NW
BAHAMAS CONTINUING TO WEST PALM BEACH FLORIDA. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE WITHIN 75 NM EITHER SIDE OF THE FRONT N
OF 26N ACROSS THE CENTRAL ATLC...WHILE ISOLATED SHOWERS ARE
WITHIN 50 NM EITHER SIDE OF THE FRONT FARTHER WESTWARD TO THE
FLORIDA PENINSULA. THIS FRONT IS LARGELY SUPPORTED BY AN UPPER
LEVEL TROUGH WITH AXIS ENTERING THE DISCUSSION AREA NEAR 32N52W
AND EXTENDING SW TO NORTH OF PUERTO RICO NEAR 20N67W AND OVER
HISPANIOLA INTO THE NORTH CENTRAL CARIBBEAN SEA. THE REMAINDER
OF THE ATLC E OF 35W IS UNDER THE INFLUENCE OF A SURFACE RIDGE
ANCHORED ON A 1022 MB HIGH CENTERED OVER SOUTHERN PORTUGAL.
STRONG NELY WINDS UP TO 20 KT ARE NOTED IN GLOBAL MODEL GUIDANCE
ALONG THE COAST OF W AFRICA FROM 16N-29N E OF 22W.

$$
HUFFMAN


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