[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021123
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN DEC 02 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 1045 UTC.

...SPECIAL FEATURE...

AN UPPER LEVEL TROUGH EXTENDS FROM A 30N43W CYCLONIC CIRCULATION
CENTER...TO 27N42W AND 22N38W. COMPARATIVELY DRIER AIR IN
SUBSIDENCE COVERS THE AREA THAT IS TO THE WEST OF THE CYCLONIC
CENTER/TROUGH...TO THE NORTH OF 20N BETWEEN 20N37W 27N41W 30N45W
AND 50W. THE CYCLONIC CENTER AND TROUGH SUPPORT A SURFACE TROUGH
THAT IS ALONG 31N42W...TO A 1008 MB LOW PRESSURE CENTER THAT
IS NEAR 29N43W. A TROUGH CURVES AWAY FROM THE 1008 MB LOW CENTER
TO 27N43W AND 24N47W. GALE-FORCE WINDS ARE IN FORECAST WATERS
WITHIN 180 NM OF THE CENTER IN THE NORTHEASTERN SEMICIRCLE.
SEA HEIGHTS RANGE FROM 10 TO 15 FEET IN THAT SAME AREA.
20 TO 30 KNOT WINDS AND 8 TO 12 FOOT SEA HEIGHTS ARE TO THE
NORTH OF 23N BETWEEN 35W AND 40W. SCATTERED MODERATE TO
ISOLATED STRONG PRECIPITATION IS FROM 23N TO 32N BETWEEN
33W AND 44W. A SECOND SURFACE TROUGH IS ALONG 23N42W 19N44W.
CLOUDS AND POSSIBLE RAINSHOWERS ARE FROM 18N TO 22N BETWEEN
40W AND 44W. SOME DEVELOPMENT OF THE 1008 MB LOW PRESSURE
CENTER STILL IS POSSIBLE BEFORE IT MERGES WITH A FRONTAL
SYSTEM IN A FEW DAYS. 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 OUTLOOK WILL BE ISSUED
FOR THIS SYSTEM LATER THIS MORNING IF IT IS NECESSARY. PLEASE
READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE DETAILS.

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

THE MONSOON TROUGH PASSES THROUGH SIERRA LEONE NEAR 9N13W
TO 8N16W. THE ITCZ CONTINUES FROM 8N16W TO 6N21W TO 9N32W
7N36W 7N44W. A 1010 MB LOW PRESSURE CENTER IS NEAR 10N49W.
A SURFACE TROUGH EXTENDS FROM THE LOW CENTER TO 11N47W
AND 12N43W. THE ITCZ CONTINUES FROM THE 10N49W LOW CENTER
TO 7N58W IN NORTHEASTERN COASTAL GUYANA. A SURFACE TROUGH IS
ALONG 34W/35W FROM 6N TO 15N. CONVECTIVE PRECIPITATION...
SCATTERED MODERATE TO ISOLATED STRONG FROM 8N TO 11N BETWEEN
58W AND TRINIDAD AND NORTHEASTERN VENEZUELA...AND FROM 2N TO 7N
BETWEEN 10W AND 25W...ISOLATED MODERATE ELSEWHERE FROM 4N TO 13N
TO THE EAST OF 53W.

...DISCUSSION...

THE GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH THE ATLANTIC
OCEAN NEAR 27N67W...ACROSS THE BAHAMAS AND THROUGH THE FLORIDA
STRAITS...TO 24N92W. RAINSHOWERS ARE POSSIBLE WITHIN 30 TO
45 NM ON EITHER SIDE OF THE LINE THAT RUNS FROM 27N93W TO
23N92W TO 22N90W. RAINSHOWERS ALSO ARE POSSIBLE ALONG THE
FLORIDA EAST COAST IN AREAS OF LOW CLOUDS THAT ARE MOVING
SOUTHWESTWARD.

A SURFACE RIDGE PASSES THROUGH SOUTHERN GEORGIA AND THE FLORIDA
BIG BEND TO 29N87W IN THE NORTHEASTERN CORNER OF THE AREA...
TO 25N93W...TO 16N97W IN SOUTHERN MEXICO...JUST TO THE WEST
OF THE ISTHMUS OF TEHUANTEPEC.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT4...FOR MORE DETAILS ABOUT
THE 20 TO 25 KNOT WINDS AND 9 FOOT SEA HEIGHTS TO THE SOUTH
OF 25N TO THE EAST OF 90W...INCLUDING IN THE FLORIDA
STRAITS...FOR THE NEXT 48 HOURS OR SO.

THE CARIBBEAN SEA...

MIDDLE LEVEL TO UPPER LEVEL WESTERLY WIND FLOW COVERS THE AREA
TO THE NORTH OF 13N. UPPER LEVEL SOUTHERLY TO SOUTHWESTERLY WIND
FLOW MOVES FROM SOUTH AMERICA AND THE EASTERN PACIFIC OCEAN INTO
THE CARIBBEAN SEA...FROM MEXICO AND THE GULF OF HONDURAS
EASTWARD.

THE MONSOON TROUGH PASSES THROUGH 8N73W IN COLOMBIA...THROUGH
THE COLOMBIA/PANAMA BORDER THAT IS NEAR 8N77W...THROUGH SOUTHERN
PANAMA NEAR 8N81W...AND BEYOND SOUTHERN COSTA RICA...INTO THE
EASTERN PACIFIC OCEAN. ISOLATED TO WIDELY SCATTERED MODERATE
CONVECTIVE PRECIPITATION IS FROM 4N TO 13N BETWEEN 73W IN
COLOMBIA AND 90W IN THE EASTERN PACIFIC OCEAN.

RAINSHOWERS ARE POSSIBLE IN BROKEN TO OVERCAST LOW TO MIDDLE
LEVEL CLOUDS THAT ARE TO THE SOUTH OF 18N TO THE WEST OF 80W
IN THE NORTHWESTERN CORNER OF THE AREA.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT
20 TO 25 KNOT WINDS AND SEA HEIGHTS LOWER THAN 8 FEET...TO THE
NORTH OF 19N BETWEEN 78W AND 84W FOR THE NEXT 24 HOURS OR SO.

THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 33N63W
TO 27N67W TO 23N74W...BEYOND THE FLORIDA STRAITS. A SHEAR LINE
IS ALONG 26N54W 25N59W 24N70W AND 22N77 NEAR THE SOUTHEASTERN
COAST OF CUBA. A SURFACE TROUGH IS ALONG 66W/67W FROM
NORTHWESTERN PUERTO RICO TO 24N. SCATTERED MODERATE TO STRONG
CONVECTIVE PRECIPITATION IS WITHIN 150 NM ON EITHER SIDE OF THE
LINE THAT RUNS FROM 31N57W TO 25N63W. RAINSHOWERS ARE POSSIBLE
ELSEWHERE FROM THE CARIBBEAN SEA NEAR 18N TO 25N BETWEEN 50W
IN THE ATLANTIC OCEAN AND 74W IN THE BAHAMAS.

AN UPPER LEVEL TROUGH PASSES THROUGH 32N10W ALONG THE MOROCCO
COAST...TO 26N17W 18N18W AND 11N20W. NO SIGNIFICANT DEEP
CONVECTIVE PRECIPITATION ACCOMPANIES THE TROUGH.

A SURFACE RIDGE PASSES THROUGH 32N23W TO 22N20W AND 11N18W
IN THE EASTERN ATLANTIC OCEAN.

A SECOND SURFACE RIDGE PASSES THROUGH CENTRAL GEORGIA...
BEYOND 29N88W...INTO THE GULF OF MEXICO.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE
DETAILS ABOUT 20 TO 25 KNOT WINDS AND 8 TO 12 FOOT SEA
HEIGHTS...RELATED TO A 31N48W 25N55W 25N67W 21N78W SHEAR LINE.

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

$$
MT





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