[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 011154
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT DEC 01 2012

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1115 UTC.

...SPECIAL FEATURE...

A SURFACE TROUGH CURVES FROM 30N44W TO A 1010 MB LOW PRESSURE
CENTER THAT IS NEAR 26N43W...TO 20N42W. THIS AREA OF LOW
PRESSURE IS BECOMING BETTER ORGANIZED GRADUALLY. MORE
DEVELOPMENT OF THIS LOW CENTER IS POSSIBLE DURING THE NEXT FEW
DAYS BEFORE IT MERGES WITH A FRONTAL SYSTEM. THIS SYSTEM HAS
A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE OR A SUBTROPICAL
CYCLONE DURING THE NEXT 48 HOURS...AS IT MOVES GENERALLY
NORTHWARD 10 TO 15 MPH. ANOTHER SPECIAL TROPICAL WEATHER
OUTLOOKS WILL BE ISSUED FOR THIS SYSTEM LATER TODAY IF
IT IS NECESSARY. CONVECTIVE PRECIPITATION...SCATTERED STRONG
FROM 26N TO 30N BETWEEN 37W AND 42W...ISOLATED MODERATE
ELSEWHERE FROM 20N TO 30N BETWEEN 30W AND 47W. AN UPPER LEVEL
RIDGE IS WITHIN 240 NM ON EITHER SIDE OF 23N32W 28N38W BEYOND
32N43W.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH GUINEA NEAR 10N14W TO 7N16W
AND 5N22W. THE ITCZ CONTINUES FROM 5N22W TO 4N27W TO 5N37W...
TO A 1009 MB LOW PRESSURE CENTER THAT IS NEAR 9N48W. CONVECTIVE
PRECIPITATION...SCATTERED STRONG FROM 4N TO 10N BETWEEN 13W AND
15W...SCATTERED STRONG WITHIN A 30 NM RADIUS OF 8.5N60W IN THE
COASTAL WATERS/COASTAL PLAINS OF VENEZUELA AND GUYANA...ISOLATED
MODERATE TO THE SOUTH OF 10N BETWEEN 56W AND 59W...WIDELY
SCATTERED TO SCATTERED MODERATE TO ISOLATED STRONG ELSEWHERE
TO THE SOUTH OF 10N TO THE EAST OF 35W...ISOLATED MODERATE
TO THE SOUTH OF 10N ELSEWHERE TO THE SOUTH OF 13N BETWEEN
35W AND 60W.

...DISCUSSION...

THE GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH THE ATLANTIC
OCEAN NEAR 32N77W...TO 26N82W IN THE EASTERN GULF OF MEXICO...
INTO THE EASTERN YUCATAN PENINSULA AND THE GULF OF HONDURAS.
A SURFACE TROUGH IS ALONG 26N91W TO THE NORTH CENTRAL COASTAL
SECTIONS OF THE YUCATAN PENINSULA. RAINSHOWERS ARE POSSIBLE
IN THE GULF OF MEXICO AND THE FLORIDA STRAITS AND THE BAHAMAS
TO THE SOUTH OF 26N BETWEEN ANDROS ISLAND AND 90W.

A 90 KT JETSTREAM EXTENDS FROM BROWNSVILLE TEXAS BEYOND
MIAMI FLORIDA. EXPECT ZONAL FLOW ALOFT TO COVER THE AREA
STARTING 24 HOURS INTO THE FORECAST PERIOD.

A SURFACE RIDGE PASSES THROUGH SOUTHERN ALABAMA...TO 26N94W
IN THE NORTHWESTERN PART OF THE AREA...BEYOND THE ISTHMUS
OF TEHUANTEPEC OF SOUTHERN MEXICO...AND INTO HONDURAS.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT4...FOR MORE DETAILS ABOUT
THE 20 TO 25 KNOT WINDS AND 8 FOOT SEA HEIGHTS FROM
23N TO 25N TO THE EAST OF 87W FOR THE NEXT 48 HOURS OR SO.

THE CARIBBEAN SEA...

REMNANTS OF A MIDDLE LEVEL TROUGH...FROM SIX HOURS AGO...ARE
ALONG 22N81W ON THE CARIBBEAN SEA SIDE OF CUBA...TO 18N81W AND
15N83W. THIS TROUGH IS UNDERNEATH UPPER LEVEL SOUTHWESTERLY WIND
FLOW. THE UPPER LEVEL SOUTHWESTERLY WIND FLOW THAT IS IN THE
WESTERN CARIBBEAN SEA IS PART OF LARGER-SCALE BROAD UPPER LEVEL
ANTICYCLONIC WIND FLOW THAT COVERS THE ENTIRE AREA. AN UPPER
LEVEL RIDGE IS ALONG 13N59W 13N65W 12N75W 12N80W. RAINSHOWERS
ARE POSSIBLE FROM HONDURAS TO 19N TO THE WEST OF 83W.

THE MONSOON TROUGH PASSES THROUGH 7N75W IN COLOMBIA...THROUGH
7N81W JUST TO THE SOUTH OF THE TIP OF SOUTHERN PANAMA...BEYOND
8N86W IN THE EASTERN PACIFIC OCEAN. WIDELY SCATTERED MODERATE
TO ISOLATED STRONG CONVECTIVE PRECIPITATION IS FROM 3N TO 12N
BETWEEN 74W IN COLOMBIA AND 90W IN THE EASTERN PACIFIC OCEAN.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT
THE FORECAST IN 42 HOURS...FOR 20 TO 25 KNOT WINDS AND SEA
HEIGHTS LOWER THAN 8 FEET...FROM 19N TO 21N BETWEEN 79W AND 84W.
EXPECT 20 TO 25 KNOT WINDS AND 8 FOOT SEA HEIGHTS IN THE
WINDWARD PASSAGE.

THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL SHEAR AXIS/TROUGH PASSES THROUGH
35N49W TO 28N48W TO 24N42W. A STATIONARY FRONT STOPS AT 32N49W.
A SHEAR AXIS CONTINUES FROM 32N49W TO 26N60W 24N68W TO 21N74W
BETWEEN THE SOUTHEASTERN BAHAMAS AND SOUTHEASTERN CUBA.
RAINSHOWERS ARE POSSIBLE FROM 20N TO 27N BETWEEN 55W AND 77W
IN THE ATLANTIC OCEAN AND IN THE BAHAMAS.

AN UPPER LEVEL TROUGH PASSES THROUGH NORTHERN MOROCCO TO THE
CANARY ISLANDS.

A SURFACE RIDGE PASSES THROUGH 33N25W TO 25N24W AND 15N21W IN
THE EASTERN ATLANTIC OCEAN.

A SECOND SURFACE RIDGE EXTENDS FROM A 1030 MB HIGH PRESSURE
CENTER THAT IS NEAR 37N70W...THROUGH SOUTH CAROLINA...INTO
SOUTHERN ALABAMA.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE
DETAILS ABOUT 20 TO 25 KNOT WINDS AND 8 TO 10 FOOT SEA HEIGHTS
WITH A 31N45W 25N43W 20N42W SURFACE TROUGH...AND 20 TO 25 KNOT
WINDS AND 8 TO 11 FOOT SEA HEIGHTS WITH A 31N50W 25N65W 21N74W
SHEAR LINE.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
MT





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