[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 141200
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED JAN 14 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1015 UTC.

...THE ITCZ...

FROM SIERRA LEONE NEAR 8N11W TO 3N20W TO 2N30W 2N39W...CROSSING
THE EQUATOR ALONG 45W...INTO NORTHEASTERN BRAZIL NEAR 2S48W.
SCATTERED STRONG SHOWERS AND THUNDERSTORMS FROM 1.5N TO 2N
BETWEEN 8W AND 10W...FROM 5.5N TO 8N BETWEEN 12W AND 16W...
AND FROM 3N TO 4N BETWEEN 17W AND 18W. SCATTERED MODERATE
SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 2N TO 5N BETWEEN
20W AND 34W. ISOLATED MODERATE SHOWERS ARE POSSIBLE ELSEWHERE
SOUTH OF 10N EAST OF 50W.

...DISCUSSION...

THE GULF OF MEXICO...AND THE ATLANTIC OCEAN WEST OF 60W...
A DEEP LAYER TROUGH HAS BEGUN TO MOVE OFF THE COAST OF THE
SOUTHEASTERN U.S.A. UPPER LEVEL SOUTHWESTERLY WIND FLOW MOVES
FROM THE SOUTHWESTERN CORNER OF THE AREA INTO CENTRAL FLORIDA
AND BEYOND 32N75W. MIDDLE TO UPPER LEVEL DRY AIR IN SUBSIDENCE
IS NORTHWEST OF 32N74W 26N90W 24N98W...WITH BROKEN TO OVERCAST
MULTILAYERED CLOUDS TO THE SOUTHEAST OF THE SAME LINE. ONE COLD
FRONT PASSES THROUGH 32N73W TO THE NORTHERN BAHAMAS...CROSSING
WESTERN CUBA...ACROSS THE NORTHWESTERN CORNER OF THE CARIBBEAN
SEA...TO BELIZE AND THE EASTERN ISTHMUS OF TEHUANTEPEC. THE
SOUTHERNMOST PART OF A DISSIPATING COLD FRONT REACHES SOUTHERN
GEORGIA. SURFACE HIGH PRESSURE HAS PUSHED ITS WAY SOUTHWARD FROM
EASTERN TEXAS/LOUISIANA TO THE NORTHERN ISTHMUS OF TEHUANTEPEC.
GALE-FORCE WIND CONDITIONS ARE BEING EXPERIENCED IN THE GULF OF
TEHUANTEPEC ON THE EASTERN PACIFIC OCEAN SIDE OF MEXICO.

THE CARIBBEAN SEA...
MIDDLE TO UPPER LEVEL DRY AIR IN SUBSIDENCE COVERS THE AREA EAST
OF 80W. A MIDDLE TO UPPER LEVEL TROUGH IS IN THE ATLANTIC OCEAN
FROM 17N49W TO 12N51W TO 9N60W. NORTHEASTERLY WIND FLOW THAT IS
ON THE NORTHERN SIDE OF THE CYCLONIC FLOW FOR THE TROUGH
EVENTUALLY MAKES ITS WAY INTO THE CARIBBEAN SEA...AND ENDS UP
BECOMING SWALLOWED UP INTO THE BROAD UPPER LEVEL ANTICYCLONIC
FLOW IN THE AREA. A TINY BIT OF THE ATLANTIC OCEAN TO GULF OF
MEXICO COLD FRONT PASSES THROUGH THE YUCATAN CHANNEL...REACHING
THE NORTHEASTERN YUCATAN PENINSULA...INTO THE EASTERN ISTHMUS OF
TEHUANTEPEC OF MEXICO. WINDS FROM THE NORTHEAST TO EAST RANGING
FROM 20 TO 30 KTS AND SEA HEIGHTS RANGING FROM 8 TO 12 FT ARE
FORECAST FOR THE NEXT 48 HOURS FROM 10N TO 18N EAST OF 82W. THE
WINDS AND SEAS ARE RELATED TO A TIGHT SURFACE PRESSURE GRADIENT
BETWEEN HIGH PRESSURE NORTH OF THE AREA AND THE SEMI-PERMANENT
SURFACE LOW PRESSURE IN COLOMBIA AND PANAMA.

THE REST OF THE ATLANTIC OCEAN EAST OF 60W...
AN UPPER LEVEL RIDGE IS ALONG 34N44W TO 25N54W TOWARD PUERTO
RICO. A MIDDLE TO UPPER LEVEL TROUGH HAS MOVED INTO THE AREA
EXTENDING FROM 32N28W TO 24N38W. 28N25W TO 20N42W TO 14N50W TO
9N60W. A SECOND MIDDLE TO UPPER LEVEL TROUGH IS ALONG 17N49W
TO 12N51W TO 9N60W. MODERATE SHOWERS ARE FROM 10N TO 17N BETWEEN
40W AND 50W. MIDDLE TO UPPER LEVEL DRY AIR IN SUBSIDENCE
SURROUNDS THIS TROUGH...FROM 4N IN THE GUYANAS AND VENEZUELA TO
30N BETWEEN UPPER LEVEL SOUTHWESTERLIES SOUTH OF 24N BETWEEN
30W AND 50W AND 80W. HIGH LEVEL CLOUDS UNDER UPPER LEVEL
SOUTHWESTERLY WIND FLOW ARE ON TOP OF LOW CLOUDS...SOUTH OF 25N
EAST OF 50W. A SURFACE RIDGE EXTENDS FROM 34N15W TO 31N25W TO
A 1029 MB HIGH PRESSURE CENTER NEAR 30N43W TO 28N60W TO 22N70W.

$$
MT





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