[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301148
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN DEC 30 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1115 UTC

...SPECIAL FEATURE...

THE EASTERN ATLANTIC DEEP LAYER CYCLONIC CIRCULATION CENTER
IS MORE OR LESS IN THE SAME SPOT THAT IT HAS BEEN RESIDING FOR
THE LAST WEEK OR SO. THE SUBTROPICAL CLASSIFICATION NUMBER IS
S-T 2.5. A HURRICANE FORECASTER WROTE A DSAAT BULLETIN AT
29/1900 UTC...THIS FEATURE THAT IS ABOUT 950 MILES SOUTHWEST
OF THE AZORES GRADUALLY HAS BEEN ACQUIRING SOME SUBTROPICAL
CHARACTERISTICS DURING THE PAST DAY OR SO. IT HAS BEEN
PRODUCING GALE-FORCE WINDS...MAINLY TO THE NORTH AND EAST
OF ITS CIRCULATION CENTER. IT IS POSSIBLE THAT IT MAY BECOME
A SUBTROPICAL STORM LATER TODAY AS IT REMAINS NEARLY STATIONARY.
FURTHER TROPICAL DISTURBANCE STATEMENTS WILL BE ISSUED AS
NECESSARY. ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE FOUND
IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...
UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC. THE
1006 MB GALE LOW PRESSURE CENTER IS NEAR 28N36W. SCATTERED
MODERATE TO STRONG SHOWERS AND THUNDERSTORMS ARE FROM 28N TO 32N
BETWEEN 32W AND 36W. A THIN LINE OF CLOUDS AND POSSIBLE SHOWERS
STILL IS ALONG 25N34W 20N37W 18N40W 13N50W 10N57W AND TO THE
COAST OF EXTREME EASTERN/NORTHEASTERN VENEZUELA NEAR 9N61W
AS IT WAS 24 HOURS AGO. PATCHES OF MULTILAYERED CLOUDS AND
POSSIBLE SHOWERS ARE ASSOCIATED WITH AN ALREADY-DISSIPATED
ATLANTIC OCEAN TROUGH...ORIGINATING FROM THE DEEP LAYER LOW
PRESSURE CENTER WITHIN 180 NM TO 240 NM NORTH OF 18N44W 15N50W
11N60W 11N70W 13N74W. THE CLOUDS/ POSSIBLE PRECIPITATION ALONG
THE WESTERN HALF OF THIS LINE ARE IN THE CARIBBEAN SEA. THE
CYCLONE SHOULD MEANDER DURING THE NEXT 36 HOURS BEFORE BEING
PUSHED TOWARD THE WEST OR SOUTHWEST BY A DEVELOPING MIDDLE-OCEAN
RIDGE ON MONDAY. TODAY MAY BE THE LAST OPPORTUNITY FOR THIS
SYSTEM TO GAIN A BIT MORE ORGANIZATION TO ITS PRECIPITATION
PATTERN AND MAKE THE TRANSITION TO A NAMED SUBTROPICAL STORM
GIVEN THAT THE VERTICAL SHEAR IS FORECAST TO INCREASE
SUBSTANTIALLY LATER TODAY.

...THE ITCZ...

FROM SOUTHERN LIBERIA TO 3N20W TO 3N30W...CROSSING THE ITCZ
ALONG 39W...INTO NORTHEASTERN BRAZIL NEAR 1S46W TO 1S52W.
ISOLATED MODERATE TO LOCALLY STRONG THUNDERSTORMS ARE SOUTH
OF 10N EAST OF 56W. UPPER LEVEL SOUTHWESTERLY WIND FLOW IS
SOUTH OF 10N60W 16N45W 22N30W 27N17W CROSSING OVER THE
NORTHERN PART OF THE WESTERN SAHARA.

...DISCUSSION...

THE GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH IS DIGGING ACROSS TEXAS. THE GULF
OF MEXICO EAST OF 90W IS COVERED BY ANTICYCLONIC FLOW FROM THE
CARIBBEAN SEA RIDGE. THE REST OF THE GULF OF MEXICO IS COVERED
BY A MIXTURE OF THE MIDDLE TO UPPER LEVEL SOUTHWESTERLY WIND FLOW
TO THE EAST OF THE TEXAS TROUGH..AND THE ANTICYCLONIC FLOW JUST
AWAY FROM THE EAST OF 90W RIDGE. THE FRONTAL BOUNDARY FROM SIX
HOURS AGO HAS BECOME STATIONARY ACROSS THE WESTERN FLORIDA
PANHANDLE...AND WARM IN THE GULF OF MEXICO FROM 29N87W TO 28N93W
TO 23N95W...AND A DISSIPATING STATIONARY FRONT TO 18N96W...
CURVING INTO MEXICO NORTHWARD NEAR 23N99W. ALL THIS HAS BEEN
OCCURRING UNDER THE ANTICYCLONIC FLOW FROM THE CARIBBEAN SEA.

THE CARIBBEAN SEA AND THE REST OF THE ATLANTIC OCEAN...
MIDDLE TO UPPER LEVEL ANTICYCLONIC WIND FLOW EXTENDS FROM
THE WEST CENTRAL CARIBBEAN SEA NORTHWARD IN ORDER TO COVER
THE GULF OF MEXICO EAST OF 90W...AND NORTHEASTWARD BEYOND
32N69W IN ORDER TO COVER THE ATLANTIC OCEAN WEST OF 60W.
UPPER LEVEL MOISTURE THAT HAD BEEN CONFINED MOSTLY TO THE
SOUTHWESTERN CORNER OF THE CARIBBEAN SEA NOW COVERS THE
NORTHWESTERN CORNER OF THE AREA. MIDDLE TO UPPER LEVEL
ANTICYCLONIC FLOW COVERS THE ENTIRE CARIBBEAN SEA BASIN.
SHOWERS ARE POSSIBLE IN BROKEN LOW CLOUDS IN SURFACE EASTERLY
WIND FLOW NORTH OF 14N WEST OF 77W. BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND POSSIBLE SHOWERS ARE ASSOCIATED WITH
AN ALREADY-DISSIPATED ATLANTIC OCEAN TROUGH...ORIGINATING FROM
THE DEEP LAYER LOW PRESSURE CENTER...WITHIN 180 NM TO 240 NM
NORTH OF 18N44W 15N50W 11N60W 11N70W 13N74W. THE CLOUDS/POSSIBLE
PRECIPITATION ALONG THE WESTERN HALF OF THIS LINE ARE IN THE
CARIBBEAN SEA.

$$
MT



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