[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 011747
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU OCT 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 35W S OF 14N MOVING W 15-20 KT. WAVE
COINCIDES WITH A SLIGHT MAXIMUM IN DEEP LAYER MOISTURE AS
INDICATED IN TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...THERE
IS NO ASSOCIATED DEEP CONVECTION. AN EARLIER QUIKSCAT PASS
INDICATED A SLIGHT CURVATURE OF THE WAVE AXIS. CLUSTERS OF
SCATTERED MODERATE CONVECTION ARE FROM 9N-12N BETWEEN 33W-39W.

TROPICAL WAVE IS ALONG 50W S OF 21N MOVING NW 10 KT. WAVE
COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL
PRECIPITABLE WATER IMAGERY. A LOW/MID LEVEL CYCLONIC CIRCULATION
IS ALONG THE WAVE AXIS NEAR 16N. WAVE IS BENEATH THE EASTERN
EDGE OF AN UPPER TROUGH ENHANCING CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 11N-17N E OF THE WAVE
TO 45W AND CLUSTERS OF SCATTERED MODERATE CONVECTION FROM
17N-21N BETWEEN 46W-52W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N14W 7N22W 7N55W 9N64W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 4N-19N E OF 16W TO THE COAST OF W AFRICA AND FROM 9N-11N
BETWEEN 19W-23W.

...DISCUSSION...

GULF OF MEXICO...
THE STATIONARY FRONT EXTENDS ACROSS EXTREME S FLORIDA PENINSULA
NEAR MIAMI TO 25N85W DISSIPATING TO 26N91W GENERATING SCATTERED/
NUMEROUS SHOWERS/THUNDERSTORMS IN THE STRAITS OF FLORIDA FROM
JUST OVER THE FLORIDA KEYS TO ACROSS CUBA E OF 83W. THE FRONT IS
SUPPORTED BY AN UPPER LEVEL TROUGH WHICH COVERS MUCH OF THE NE
US AND EXTENDING AN AXIS S JUST OFF THE CAROLINA COAST INTO THE
NE GULF NEAR TAMPA TO AN UPPER LOW OVER W CUBA NEAR 23N82W INTO
THE NW CARIBBEAN. AN UPPER RIDGE EXTENDS ACROSS MEXICO NEAR
TAMPICO NE TO OVER THE LOWER MISSISSIPPI VALLEY. THIS IS LEAVING
MOST OF THE GULF UNDER DRY STABLE AIR AND RELATIVELY CLEAR
SKIES.

CARIBBEAN SEA...
UPPER LEVEL TROUGH OVER THE E GULF OF MEXICO EXTENDS TO OVER THE
NW CARIBBEAN WITH AN UPPER LOW OVER W CUBA NEAR 23N82W USHERING
IN DRY STABLE AIR OVER THE AREA N OF 15N E OF 82W. SCATTERED/
NUMEROUS SHOWERS/THUNDERSTORMS IN THE STRAITS OF FLORIDA EXTEND
ACROSS CUBA INTO THE NW CARIBBEAN N OF 18N BETWEEN 77W-83W.
BROAD UPPER RIDGE AXIS EXTENDS FROM E PANAMA NE TO HISPANIOLA
AND COUPLED WITH THE ITCZ JUST S OF PANAMA IS GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE SW CARIBBEAN S
OF A LINE FROM COLOMBIA NEAR 10N75W TO NICARAGUA NEAR 13N84W.
MOSTLY CLEAR SKIES PREVAIL ACROSS THE REMAINDER OF THE CARIBBEAN
WITH THE EXCEPTION OF A FEW ISOLATED SHOWERS BEING USHERED IN ON
MODERATE TO FRESH EASTERLY TRADE WINDS.

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE REGION NEAR 32N62W EXTENDING SW TO THE
BAHAMA ISLANDS NEAR 26N77W BECOMING STATIONARY ACROSS EXTREME S
FLORIDA INTO THE GULF OF MEXICO NEAR MIAMI SUPPORTED BY AN UPPER
TROUGH WHICH COVERS MUCH OF THE NE US AND EXTENDS AN AXIS S JUST
OFF THE CAROLINA COAST ACROSS FLORIDA INTO THE NE GULF NEAR
DAYTONA BEACH. SCATTERED/NUMEROUS SHOWERS/THUNDERSTORMS ARE S OF
THE FRONT W OF 75W THROUGH THE STRAITS OF FLORIDA WITH CLUSTERS
OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 180 NM EITHER
SIDE OF THE REMAINDER OF THE FRONT W OF 65W. A BROAD UPPER RIDGE
COVERS THE REMAINDER OF THE W ATLC INTO THE CENTRAL ATLC
EXTENDING FROM THE CARIBBEAN ACROSS HISPANIOLA ALONG 25N60W THEN
N TO BEYOND 32N56W. DIFFLUENCE ALOFT IS ENHANCING SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS OVER A BROAD AREA
FROM 26N-31N BETWEEN 44W-62W. A SURFACE TROUGH EXTENDS FROM
20N58W THROUGH A SMALL LOW/MID LEVEL CYCLONIC SWIRL NEAR 17N60W
TO BARBADOS WITH SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF
THE TROUGH N OF 16N. AN UPPER TROUGH IN THE CENTRAL ATLC EXTENDS
FROM AN UPPER LOW NEAR 25N49W S INTO THE TROPICS TO 16N53W WHICH
IS ENHANCING THE ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE
ALONG 50W. BROAD DEEP LAYERED LOW IS N OF THE REGION WITH AN
UPPER TROUGH EXTENDING S OVER THE NE ATLC TO 26N BETWEEN 20W-40W
AND AN ASSOCIATED COLD FRONT ENTERING THE REGION NEAR 32N79W
31N34W THEN NE TO BEYOND 32N42W. A PRE-FRONTAL SURFACE TROUGH
EXTENDS FROM 32N22W ALONG 28N32W TO 28N43W WITH SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90 NM EITHER SIDE OF THE
TROUGH E OF 30W AND WITHIN 60 NM EITHER SIDE OF THE REMAINDER OF
THE TROUGH. WEAK SURFACE RIDGE DOMINATES THE REMAINDER OF THE
ATLC THROUGH A SERIES OF HIGHS...A 1020 MB HIGH JUST N OF THE
CANARY ISLANDS SW TO A 1019 MB HIGH 21N34W NE TO A 1018 MB HIGH
NEAR 25N62W.

$$
WALLACE



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