[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE OCT 17 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

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

...SPECIAL FEATURE...
A DEEP LAYER TROUGH COVERS THE AREA FROM THE ATLANTIC OCEAN
THROUGH 32N58W TO 25N62W TO 20N64W TO 15N66W TO THE PENINSULA
DE PARAGUANA ALONG THE NORTHWESTERN COAST OF VENEZUELA NEAR
12N70W. A COLD FRONT PASSES THROUGH 32N50W TO 30N51W.
A SURFACE TROUGH CONTINUES FROM 30N51W TO 25N60W TO 22N64W
TO A 1008 MB LOW PRESSURE CENTER NEAR 20N66W. A TROUGH GOES
FROM THE LOW PRESSURE CENTER ACROSS CENTRAL PUERTO RICO TO
15N68W. AN EASTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 65W/66W
SOUTH OF 18N MOVING WEST 10 TO 15 KT. THIS WAVE IS MOVING INTO
THE AREA ALREADY OCCUPIED BY A DEEP LAYER TROUGH. THIS TROUGH
RUNS FROM THE WESTERN ATLANTIC OCEAN...ACROSS PUERTO RICO...AND
INTO THE SOUTHEASTERN CARIBBEAN SEA. SCATTERED MODERATE SHOWERS
TO ISOLATED STRONG THUNDERSTORMS FROM 12N TO 18N BETWEEN 62W AND
68W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 20N TO 22N
BETWEEN 61W AND 64W AT THE EDGE OF THE NORTHEASTERN CORNER OF
THE CARIBBEAN SEA. ISOLATED MODERATE SHOWERS ARE ELSEWHERE FROM
11N TO 17N BETWEEN 70W AND 80W IN UPPER LEVEL DIFFLUENT FLOW.
UPPER LEVEL WINDS ARE NOT CONDUCIVE FOR TROPICAL CYCLONE
DEVELOPMENT. IT IS LIKELY THAT THIS SYSTEM WILL PRODUCE
LOCALLY HEAVY RAINFALL OVER SECTIONS OF PUERTO RICO...
THE VIRGIN ISLANDS...AND THE LEEWARD ISLANDS DURING
THE NEXT FEW DAYS AS IT MOVES SLOWLY SOUTHWESTWARD.

...TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 36W/37W SOUTH OF 18N
MOVING WEST 10 TO 15 KT. UPPER LEVEL SOUTHWESTERLY WIND FLOW
IS MOVING ACROSS THE AREA OF THE WAVE ON THE SOUTH AND
SOUTHEASTERN SIDE OF A MIDDLE TO UPPER LEVEL CENTRAL ATLANTIC
OCEAN TROUGH. ISOLATED MODERATE SHOWERS AND POSSIBLE
THUNDERSTORMS ARE FROM THE EQUATOR TO 10N BETWEEN 30W AND 38W.
POSSIBLE SHOWERS FROM 10N TO 16N BETWEEN 30W AND 40W.

A TROPICAL WAVE IS ALONG 93W/94W SOUTH OF 18N MOVING WEST
10 TO 15 KT. THE NORTHERN PART OF THIS WAVE IS MOVING THROUGH
THE ISTHMUS OF TEHUANTEPEC. THE REST OF THE WAVE IS IN THE
EASTERN PACIFIC OCEAN. NO DEEP CONVECTIVE PRECIPITATION IS
OVER LAND AT THIS TIME.

...THE ITCZ...
11N12W 8N20W 6N30W 6N35W 6N38W 5N50W 5N54W. STRONG SHOWERS AND
THUNDERSTORMS FROM 13N TO 15N BETWEEN 24W AND 25W. WIDELY
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM
4N TO 10N BETWEEN 25W AND 30W. OTHER SHOWERS AND THUNDERSTORMS
ALSO ARE POSSIBLE FROM 10N TO 18N BETWEEN 20W AND 30W.
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE
FROM 10N TO 12N BETWEEN 39W AND 51W.

...DISCUSSION...
GULF OF MEXICO...
AN UPPER LEVEL NORTH CENTRAL GULF OF MEXICO ANTICYCLONIC
CIRCULATION HAS SPREAD ANTICYCLONIC FLOW IN THE UNITED STATES
OF AMERICA FROM THE SOUTHEASTERN CORNER TO THE MIDDLE ATLANTIC
STATES...INTO THE ATLANTIC OCEAN NORTH OF 20N WEST OF 67W...
AND INTO A LARGE PART OF THE CARIBBEAN SEA...TO THE WEST OF
A DEEP LAYER TROUGH THROUGH 20N64W TO 12N70W AT THE NORTHWESTERN
VENEZUELA COAST. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED NEAR A SQUALL LINE. THE SQUALL LINE IS ALONG 27N93W
29N90W 32N88W. SCATTERED TO NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS ARE WITHIN 30 NM ON EITHER SIDE OF 29N90W 30N87W
32N84W.

CARIBBEAN SEA...
UPPER LEVEL ANTICYCLONIC FLOW COVERS THE CARIBBEAN SEA
EVERYWHERE TO THE WEST OF THE DEEP LAYER TROUGH...FROM THE
ATLANTIC OCEAN THROUGH 32N58W TO 20N64W TO THE NORTHWESTERN
VENEZUELA COAST. MIDDLE TO UPPER LEVEL DRY AIR COVERS THE AREA
TO THE WEST OF THE ATLANTIC OCEAN-TO-CARIBBEAN SEA TROUGH.
THIS ANTICYCLONIC FLOW IS COURTESY OF A NORTH CENTRAL GULF OF
MEXICO ANTICYCLONIC CIRCULATION CENTER.

ATLANTIC OCEAN...
UPPER LEVEL ANTICYCLONIC FLOW...AROUND A NORTH CENTRAL GULF OF
MEXICO ANTICYCLONIC CIRCULATION CENTER...COVERS THE WESTERN
ATLANTIC OCEAN WATERS NORTH OF 20N WEST OF 67W. AN UPPER LEVEL
RIDGE PASSES THROUGH 22N45W TO 27N43W BEYOND 32N41W. A DEEP
LAYER TROUGH AS SEEN ON WATER VAPOR IMAGERY PASSES THROUGH
32N22W TO 26N28W. A COLD FRONT PASSES THROUGH 34N10W TO 31N14W.
A SEPARATE MIDDLE TO UPPER LEVEL TROUGH GOES FROM 23N27W TO
20N36W TO 16N49W. SOME MIDDLE TO UPPER LEVEL DRY AIR IS WITHIN
120 NM ON EITHER SIDE OF THE SEPARATE TROUGH BETWEEN 25W AND
49W. MIDDLE TO UPPER LEVEL DRY AIR IS UNDER THE RIDGE IS NORTH
OF 17N BETWEEN 34W AND 50W.

$$
MT



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