[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 121726
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST MON DEC 12 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...
METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1615 UTC.

...THE ITCZ...
7N11W 4N20W 4N30W 3N40W 2N50W INTO NORTHEASTERN BRAZIL NEAR
2N52W. WIDELY SCATTERED MODERATE SHOWERS TO ISOLATED STRONG
THUNDERSTORMS FROM 2N TO 6N BETWEEN 15W AND 22W. SHOWERS ARE
POSSIBLE IN LOW CLOUDS FROM 1N TO 5N BETWEEN 32W AND 52W.

...DISCUSSION...
THE GULF OF MEXICO...
UPPER LEVEL SOUTHWESTERLY TO WESTERLY WIND FLOW MOVES FROM THE
EASTERN PACIFIC OCEAN ACROSS MEXICO NORTH OF 20N...TO THE BASE
OF A DEEP LAYER TROUGH NEAR 26N95W. THIS TROUGH STARTS OUT IN
THE CENTRAL U.S.A. AND REACHES THE NORTHWESTERN GULF WATERS.
A SURFACE TROUGH IS ALONG 31N93W TO 27N94W. A COLD FRONT IS IN
THE TEXAS GULF COAST PLAINS SET TO ENTER THE NORTHWESTERN GULF
OF MEXICO WATERS DURING THE NEXT SIX HOURS OR LESS. MIDDLE TO
UPPER LEVEL DRY AIR IS EVERYWHERE IN TEXAS TO THE NORTHWEST OF
THE FRONT. A BAND OF UPPER LEVEL MOISTURE RIDING ALONG THE
ACCOMPANYING WIND MAXIMA/JET STREAM IS WITHIN 90 NM ON EITHER
SIDE OF 22N107W 26N94W BEYOND 31N86W. A MIDDLE TO UPPER LEVEL
RIDGE IS ALONG 80W FROM 20N NORTHWARD OVER CUBA AND FLORIDA
TOWARD SOUTH CAROLINA. BROKEN TO OVERCAST MULTILAYERED
CLOUDINESS AND SHOWERS ARE UNDER THIS RIDGE...FROM 20N TO 26N
BETWEEN 80W AND 85W. SURFACE TO LOW LEVEL CYCLONIC FLOW EXTENDS
FROM THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA...THROUGH THE
YUCATAN CHANNEL...INTO THE EAST CENTRAL GULF OF MEXICO.
BROKEN TO OVERCAST LOW TO MIDDLE LEVEL CLOUDS AND POSSIBLE
SHOWERS HAVE BEEN IN THE GULF WATERS EAST OF 90W FOR THE LAST
FEW DAYS. SIMILAR CLOUDS AND PRECIPITATION ARE SOUTH OF 24N
BETWEEN 90W AND THE MEXICO COAST.

THE CARIBBEAN SEA...
SURFACE TO LOW LEVEL CYCLONIC FLOW EXTENDS FROM THE NORTHWESTERN
CORNER OF THE CARIBBEAN SEA...THROUGH THE YUCATAN CHANNEL...INTO
THE EAST CENTRAL GULF OF MEXICO. A TROUGH...POSSIBLY THE REMNANT
OF AN OLD FRONTAL BOUNDARY...REMAINS EITHER FROM THE
NORTHWESTERN WATERS INTO THE YUCATAN PENINSULA AND/OR NORTHWARD
THROUGH THE YUCATAN CHANNEL INTO THE SOUTHEASTERN GULF OF
MEXICO. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS
ARE NORTH OF THE HONDURAS COAST TO CUBA AND THE YUCATAN CHANNEL
WEST OF 80W. BROAD SURFACE TO LOW LEVEL CYCLONIC FLOW IN THE
CLOUD FIELD ON VISIBLE SATELLITE IMAGERY COVERS THE AREA FROM
THE CENTRAL CARIBBEAN SEA INTO THE WEST-CENTRAL SECTIONS IN
TRADE WIND FLOW. SHOWERS ARE POSSIBLE FROM THE CENTRAL WATERS
TO THE WEST-CENTRAL WATERS. UPPER LEVEL SOUTHERLY WINDS ARE
BLOWING FROM THE EQUATOR OVER SOUTH AMERICA NORTHWARD...HAVING
LITTLE TO NO INFLUENCE OVER THE CARIBBEAN SEA. MIDDLE LEVEL FLOW
IS NORTHEASTERLY TO EASTERLY...ACCORDING TO SATELLITE IMAGERY
AND THE 12/1200 UTC CIMSS SATELLITE DERIVED WIND DATA. MIDDLE
TO UPPER LEVEL DRY AIR STILL REMAINS SOUTH OF 20N EAST OF
CENTRAL AMERICA.

THE ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH PASSES THROUGH 34N52W TO 28N55W
TO THE NORTHEASTERN CARIBBEAN SEA NEAR 18N63W. THIS TROUGH IS
SUPPORTING THE COLD FRONT THROUGH 31N45W TO 26N50W TO 22N58W.
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE
WITHIN 30 TO 60 NM ON EITHER SIDE OF THE LINE THROUGH 32N43W TO
29N44W TO 25N46W. AN UPPER LEVEL RIDGE IS BEING SQUEEZED IN
BETWEEN THE APPROACHING TROUGH AND THE CYCLONIC FLOW AROUND
A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER NEAR 24N31W.
CYCLONIC FLOW AROUND THIS CENTER ROUGHLY COVERS THE ATLANTIC
WATERS FROM 14N TO 30N BETWEEN 20W AND 40W. AN UPPER LEVEL RIDGE
GOES FROM 25N20W BEYOND 32N27W. A SURFACE TROUGH IS ALONG 19N41W
16N44W 12N47W. SHOWERS ARE WITHIN 30 TO 60 NM ON EITHER SIDE OF
THE TROUGH. THE ATLANTIC WATERS FROM 10N TO 20N BETWEEN 45W AND
60W ARE IN A SEPARATE AREA OF MIDDLE LEVEL CYCLONIC FLOW. THE
UPPER LEVEL SOUTHERLY FLOW TO THE SOUTH OF THIS AREA IS MOVING
TOWARD IT AND POSSIBLY OVER THE TOP OF IT...BUT ALSO THE
SOUTHERLY FLOW SIMPLY IS MOVING AROUND IT AND/OR TO THE
SIDE OF IT.

$$
MT




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