[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 270601
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT OCT 27 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC.

...SPECIAL FEATURES...

THE CENTER OF HURRICANE SANDY AT 27/0600 UTC IS NEAR
28.1N 76.9W. SANDY IS PULLING AWAY FROM THE BAHAMAS...NOW
ABOUT 105 NM TO THE NORTH OF GREAT ABACO ISLAND IN THE NORTHERN
BAHAMAS...AND ABOUT 325 NM TO THE SOUTH-SOUTHEAST OF CHARLESTON
SOUTH CAROLINA. SANDY IS MOVING NORTHWARD 6 KT. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 969 MB. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 65 KNOTS WITH GUSTS TO 80 KNOTS. PLEASE READ THE
FORECAST/ ADVISORY UNDER THE AWIPS/WMO HEADERS MIATCMAT3/
WTNT23 KNHC...AND THE PUBLIC ADVISORY UNDER MIATCPAT3/
WTNT33 KNHC FOR MORE DETAILS. CONVECTIVE PRECIPITATION...
SCATTERED STRONG FROM 27N TO 32N BETWEEN 77W AND 80W AND FROM
26N TO 27N BETWEEN 65W AND 67W AND FROM 26N TO 27N ALONG
70W...NUMEROUS STRONG WITHIN A 60 NM RADIUS OF 22N64W...
SCATTERED MODERATE TO ISOLATED STRONG ELSEWHERE FROM 17N
IN THE CARIBBEAN SEA ACROSS HISPANIOLA AND PUERTO RICO
BEYOND 32N BETWEEN 60W AND 80W. THE SURFACE PRESSURE PATTERN
OF LOW PRESSURE COVERS THE CARIBBEAN SEA FROM 14N TO 34N
IN THE ATLANTIC OCEAN BETWEEN 65W IN THE ATLANTIC OCEAN
AND 85W IN THE EASTERN GULF OF MEXICO AND IN THE
NORTHWESTERN CARIBBEAN SEA...IN A CLOSED 1008 MB ISOBAR.
A DEVELOPING WARM FRONT IS ALONG 25N62W 28N66W 30N70W.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 17N45W 13N44W 10N43W.
IT HAS BEEN MOVING WESTWARD 10 KNOTS DURING THE LAST 24 HOURS.
CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO STRONG FROM
10N TO 14N BETWEEN 38W AND 43W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 16N51W 13N49W 11N47W
MOVING WESTWARD 10 KNOTS DURING THE LAST 24 HOURS. CONVECTIVE
PRECIPITATION...ISOLATED MODERATE FROM 13N TO 16N BETWEEN 48W
AND 51W. AN UPPER LEVEL TROUGH PASSES THROUGH 32N46W TO 27N44W
22N43W TO 18N44W AND 16N46W. AN INVERTED MIDDLE LEVEL TO UPPER
LEVEL TROUGH IS ALONG 16N47W 14N49W 10N56W BEYOND SOUTHEASTERN
VENEZUELA. SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE
PRECIPITATION IS FROM 5N TO 8N BETWEEN 43W AND 47W.
THE TROUGHS ARE IN THE AREA OF THIS TROPICAL WAVE.

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

THE MONSOON TROUGH PASSES THROUGH COASTAL GAMBIA NEAR 13N17W
TO 11N19W. THE ITCZ CONTINUES FROM 11N19W TO 6N29W AND 11N37W.
THE ITCZ IS BROKEN UP BY THE WIND FLOW THAT IS AROUND THE
TROPICAL WAVES. THE ITCZ CONTINUES FROM 8N49W TO 7N54W...INTO
NORTHEASTERN GUYANA NEAR 7N59W. CONVECTIVE PRECIPITATION...
SCATTERED MODERATE TO ISOLATED STRONG TO THE SOUTH OF 10N
BETWEEN 20W AND 38W...ISOLATED MODERATE TO LOCALLY STRONG
FROM 4N TO 10N TO THE EAST OF 20W.

...DISCUSSION...

THE GULF OF MEXICO...

A DEEP LAYER TROUGH THAT IS MOVING THROUGH THE CENTRAL U.S.A.
IS SUPPORTING A COLD FRONT THAT PASSES THROUGH SOUTHERN
MISSISSIPPI INTO SOUTHEASTERN LOUISIANA...INTO THE NORTHWESTERN
GULF OF MEXICO...TO 24N98W IN NORTHERN COASTAL MEXICO.
A STATIONARY FRONT CONTINUES FROM 24N98W...TO JUST TO THE SOUTH
OF THE TEXAS BIG BEND...BEYOND 32N107W. ISOLATED MODERATE
CONVECTIVE PRECIPITATION IS TO THE NORTHWEST OF THE LINE THAT
PASSES THROUGH 22N98W 26N92W 30N89W. DEEP LAYER NORTHWESTERLY
WIND FLOW COVERS THE AREA.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT4...FOR DETAILS ABOUT 20 TO 30 KNOT
WINDS AND 8 TO 13 FOOT SEA HEIGHTS TO THE EAST OF A LINE THAT
RUNS FROM 30N85W 26N88W 22N84W TO START THE FORECAST PERIOD...
AND THAT MOVES TO 30N86W 25N85W 23N83W AT 24 HOURS. THE 48 HOUR
CONDITIONS WILL MERGE WITH A COLD FRONT. THE COLD FRONT STARTS
NEAR 29N91W 26N95W 24N98W AT THE START...NEAR 30N89W 23N94W
18N94W AT 24 HOURS...AND TO 28N83W 25N88W 23N94W 18N95W AT
48 HOURS. EXPECT 20 TO 30 KNOT WIND SPEEDS AND 8 TO 11 FOOT
SEA HEIGHTS AROUND THE FRONT.

THE CARIBBEAN SEA...

A MIDDLE LEVEL TO UPPER LEVEL SHORT WAVE TROUGH PASSES THROUGH
ANDROS ISLAND IN THE BAHAMAS...ACROSS CUBA...TO 18N79W IN THE
CARIBBEAN SEA TO 11N82W IN THE SOUTHWESTERN CORNER OF THE AREA.
COMPARATIVELY DRIER AIR IN SUBSIDENCE SURROUNDS THE TROUGH.
THIS TROUGH IS PART OF THE FEATURE THAT WAS A 22N82W CYCLONIC
CIRCULATION CENTER ON 25N/1200 UTC. NO SIGNIFICANT DEEP
CONVECTIVE PRECIPITATION ACCOMPANIES THIS SHORT WAVE TROUGH.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT3...FOR DETAILS ABOUT 20 TO 30 KNOT
WINDS AND 8 TO 12 FOOT SEA HEIGHTS TO THE NORTHEAST OF THE LINE
FROM 22N83W TO 16N78W AND TO 16N70W FOR THE NEXT 24 HOURS OR SO.

THE ATLANTIC OCEAN...

AN UPPER LEVEL TROUGH PASSES THROUGH 32N46W TO 27N44W 22N43W
TO 18N44W AND 16N46W. THE TROUGH SUPPORTS A COLD FRONT THAT
PASSES THROUGH 32N41W TO 27N48W AND 26N57W. BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND SCATTERED MODERATE TO ISOLATED STRONG
CONVECTIVE PRECIPITATION ARE TO THE NORTH OF 21N BETWEEN 30W
AND 60W.

A COLD FRONT EXTENDS FROM A 1008 MB LOW PRESSURE CENTER THAT
IS NEAR 32N24W...TO 30N25W 28N27W 25N32W. ISOLATED MODERATE
TO LOCALLY STRONG CONVECTIVE PRECIPITATION IS TO THE NORTH
OF 26N BETWEEN AFRICA AND 30W.

A 1016 MB HIGH PRESSURE CENTER IS NEAR 25N22W. SURFACE
ANTICYCLONIC WIND FLOW MOVES AROUND THE HIGH CENTER FROM
THE CAPE VERDE ISLANDS TO 27N BETWEEN AFRICA AND THE
32N24W 25N32W COLD FRONT.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR DETAILS
ABOUT HURRICANE SANDY. A SECOND AREA OF INTEREST RELATES TO
A COLD FRONT THAT IS ALONG 32N41W 27N48W 26N57W...A NEW COLD
FRONT FORMS AT 24 HOURS ALONG 31N42W 28N50W 31N60W. THE COLD
FRONT MOVES TO 31N40W 27N42W 24N56W BY 48 HOURS. EXPECT
20 TO 30 KNOT WINDS AND 8 TO 13 FOOT SEA HEIGHTS AROUND THE
COLD FRONT.

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

$$
MT




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