[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 040621
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU OCT 04 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0345 UTC.

...SPECIAL FEATURES...

A GULF OF MEXICO 1004 MB LOW PRESSURE CENTER IS NEAR 27N88W.
THIS IS A NON-TROPICAL AREA OF LOW PRESSURE AT THE MOMENT.
THIS SYSTEM STILL HAS A WELL-DEFINED LOW-LEVEL CIRCULATION AND
IT IS POSSIBLE THAT THIS SYSTEM MAY BECOME A TROPICAL OR
SUBTROPICAL DEPRESSION DURING THE NEXT DAY OR SO AS IT MOVES
GENERALLY NORTHWESTWARD ABOUT 10 MPH. RESIDENTS IN THE
NORTHERN GULF OF MEXICO COAST SHOULD CONTINUE TO MONITOR THE
PROGRESS OF THIS SYSTEM. A BIG MIDDLE TO UPPER LEVEL TROUGH IS
ON TOP OF THE GULF OF MEXICO FROM THE NORTHEASTERN CORNER OF THE
AREA TO THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO...AND EVEN
PASSING OVER INTERIOR MEXICO TO THE EASTERN PACIFIC COAST AND
EVENTUALLY INTO THE EASTERN PACIFIC OCEAN NEAR 13N100W. MODERATE
SHOWERS FROM 26N TO 29N BETWEEN 86W AND 89W. A BIG MIDDLE TO
UPPER LEVEL TROUGH IS ON TOP OF THE GULF OF MEXICO FROM THE
NORTHEASTERN CORNER OF THE AREA TO THE SOUTHWESTERN CORNER OF
THE GULF OF MEXICO...AND EVEN PASSING OVER INTERIOR MEXICO AND
EVENTUALLY INTO THE EASTERN PACIFIC OCEAN NEAR 13N100W.

A SURFACE TROUGH IS ALONG 30N70W TO THE BAHAMAS NEAR 25N76W...
CROSSING CUBA TO 21N81W IN THE CARIBBEAN SEA. STRONG SHOWERS
AND THUNDERSTORMS IN CLUSTERS FROM 40 NM SOUTHEAST OF JAMAICA
TO THE CUBA COASTAL WATERS NEAR 80W TO THE WESTERN HALF OF
HAITI...FROM 20N TO 26N BETWEEN 70W AND 76W. UPPER LEVEL
ANTICYCLONIC FLOW COVERS THE AREA FROM THE CARIBBEAN SEA NEAR
13N TO THE ATLANTIC OCEAN NEAR 32N BETWEEN 60W AND 84W.
THE PRECIPITATION IN THIS AREA REMAINS DISORGANIZED...AND
THERE IS NO EVIDENCE OF A SURFACE CIRCULATION AT THIS TIME.
UPPER-LEVEL WINDS APPEAR TO BE SOMEWHAT FAVORABLE FOR
DEVELOPMENT. IT IS POSSIBLE THAT A TROPICAL DEPRESSION MAY
FORM IN THIS AREA DURING THE NEXT DAY OR TWO. THIS FEATURE
IS EXPECTED TO BEGIN A SLOW WESTWARD MOTION ON THURSDAY.

A 1012 MB LOW PRESSURE CENTER IS ALONG A 43W/44W TROPICAL WAVE
THAT IS SOUTH OF 15N...AND MOVING WEST 10 TO 15 KT. SCATTERED
STRONG SHOWERS AND THUNDERSTORMS FROM 11N TO 12N BETWEEN 44W
AND 46W...AND FROM 15.5N TO 18N BETWEEN 43W AND 46W. ISOLATED
MODERATE SHOWERS ARE ELSEWHERE FROM 10N TO 20N BETWEEN 40W AND
47W. UPPER-LEVEL WINDS ARE EXPECTED TO BECOME GRADUALLY LESS
FAVORABLE FOR DEVELOPMENT OVER THE NEXT COUPLE OF DAYS AS IT
TRACKS WESTWARD ALTHOUGH THIS SYSTEM IS SHOWING SIGNS OF
ORGANIZATION.

THE REMNANTS OF TROPICAL DEPRESSION MELISSA ARE ABOUT 1070 NM
EAST-SOUTHEAST OF BERMUDA. SIGNIFICANT RE-DEVELOPMENT IS NOT
EXPECTED DUE TO STRONG UPPER-LEVEL WINDS. THIS IS A 1016 MB
LOW PRESSURE CENTER NEAR 21.5N 48.5W. A NARROW MIDDLE TO UPPER
LEVEL TROUGH IS TO THE WEST ALONG 28N59W 22N57W. A DEEP LAYER
LEVEL TROUGH PASSES THROUGH 32N35W 29N46W. UPPER LEVEL
SOUTHWESTERLY WIND FLOW MOVES FROM 23N46W NORTHEASTWARD. UPPER
LEVEL SOUTHERLY FLOW MOVES FROM 16N49W TOWARD THE NORTH AND
NORTHEAST.

...TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 52W/53W SOUTH OF 15N
MOVING WEST 10 TO 15 KT. NO PRECIPITATION ACCOMPANIES THIS WAVE.

...THE ITCZ...
11N15W 7N20W 7N26W 7N30W 10N41W 10N46W 10N52W 10N56W 10N67W.
ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS SOUTH OF
10N BETWEEN 10W AND 46W.

DISCUSSION...

THE GULF OF MEXICO...THE ATLANTIC OCEAN WEST OF 60W...
AND THE NORTHWESTERN CARIBBEAN SEA...
ONE BIG MIDDLE TO UPPER LEVEL TROUGH STRETCHES FROM THE
NORTHEASTERN CORNER OF THE AREA TO THE SOUTHWESTERN
CORNER...INCLUDING ACROSS THE ISTHMUS OF TEHUANTEPEC...
INTO THE EASTERN PACIFIC COAST NEAR 13N100W. A FEW CYCLONIC
SWIRLS/CIRCULATION CENTERS ARE EMBEDDED IN THIS TROUGH.
A 1004 MB LOW PRESSURE CENTER IS NEAR 27N88W. THIS LOW
PRESSURE CENTER APPEARS ON THE TAFB DANGER GRAPHIC. IT IS
POSSIBLE THAT THIS SYSTEM MAY BECOME A TROPICAL OR SUBTROPICAL
DEPRESSION DURING THE NEXT DAY OR SO AS IT MOVES GENERALLY
NORTHWESTWARD ABOUT 10 MPH. RESIDENTS IN THE NORTHERN GULF OF
MEXICO COAST SHOULD CONTINUE TO MONITOR THE PROGRESS OF THIS
SYSTEM. MODERATE SHOWERS FROM 26N TO 29N BETWEEN 86W AND 89W.
A SURFACE TROUGH IS ALONG 30N70W TO THE BAHAMAS NEAR 25N76W...
CROSSING CUBA TO 21N81W IN THE CARIBBEAN SEA. STRONG SHOWERS AND
THUNDERSTORMS IN CLUSTERS FROM 40 NM SOUTHEAST OF JAMAICA TO THE
CUBA COASTAL WATERS NEAR 80W TO THE WESTERN HALF OF HAITI...FROM
20N TO 26N BETWEEN 70W AND 76W. UPPER LEVEL ANTICYCLONIC FLOW
COVERS THE AREA FROM THE CARIBBEAN SEA NEAR 13N TO THE ATLANTIC
OCEAN NEAR 32N BETWEEN 60W AND 84W. THE PRECIPITATION IN THIS
AREA REMAINS DISORGANIZED...AND THERE IS NO EVIDENCE OF
A SURFACE CIRCULATION AT THIS TIME.  UPPER-LEVEL WINDS APPEAR
TO BE SOMEWHAT FAVORABLE FOR DEVELOPMENT. IT IS POSSIBLE THAT
A TROPICAL DEPRESSION MAY FORM IN THIS AREA DURING THE NEXT DAY
OR TWO. THIS FEATURE IS EXPECTED TO BEGIN A SLOW WESTWARD MOTION
ON THURSDAY.

THE CARIBBEAN SEA...
MIDDLE TO UPPER LEVEL CYCLONIC FLOW CUTS ACROSS THE YUCATAN
PENINSULA INTO A TINY PART OF THE NORTHWESTERN CORNER OF THE
AREA. THIS FLOW IS MET BY UPPER LEVEL ANTICYCLONIC FLOW TO THE
EAST OF IT...NORTH OF 13N BETWEEN 58W IN THE ATLANTIC OCEAN AND
THE NORTHEASTERN COAST OF NICARAGUA. WEAKENING MIDDLE LEVEL
CYCLONIC FLOW APPEARS TO BE DISSIPATING NEAR 10N60W. MIDDLE TO
UPPER LEVEL DRY AIR/SUBSIDENCE RESTS ACROSS VENEZUELA NORTH OF
7N...AND IN PARTS OF THE CARIBBEAN SEA SOUTH OF 15N BETWEEN 64W
AND 75W. A SURFACE TROUGH IS ALONG 30N70W TO THE BAHAMAS NEAR
25N76W...CROSSING CUBA TO 21N81W IN THE CARIBBEAN SEA. STRONG
SHOWERS AND THUNDERSTORMS IN CLUSTERS FROM 40 NM SOUTHEAST OF
JAMAICA TO THE CUBA COASTAL WATERS NEAR 80W TO THE WESTERN HALF
OF HAITI...FROM 20N TO 26N BETWEEN 70W AND 76W.

THE REST OF THE ATLANTIC OCEAN EAST OF 60W...
A DEEP LAYER TROUGH GOES PASSES THROUGH 32N35W TO 29N46W. THIS
TROUGH SUPPORTS THE COLD FRONT THAT PASSES THROUGH 32N31W TO
30N34W TO 28N43W. ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS
FROM 25N TO 30N BETWEEN 50W AND 54W...AND FROM 29N TO 30N
BETWEEN 56W AND 60W. ISOLATED MODERATE SHOWERS ARE ABOUT 240 NM
TO THE SOUTH AND SOUTHEAST OF THE COLD FRONT BETWEEN 29W AND
49W...INCLUDING SOME SHOWERS NEAR THE REMNANT LOW OF MELISSA.
AN UPPER LEVEL RIDGE IS ALONG 10N37W 18N36W TO 22N34W. DEEP
LAYER CYCLONIC FLOW COVERS SPAIN/PORTUGAL/THE NORTHERN HALF OF
MOROCCO. AN UPPER LEVEL RIDGE IS ALONG 17N41W 23N36W 26N31W
BEYOND 32N26W.

$$
MT




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