[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211142
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN OCT 21 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 FEATURES...

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 75W...FROM THE COAST OF
CUBA NEAR 20N TO THE COAST OF COLOMBIA. A 1006 MB LOW PRESSURE
CENTER IS ALONG THE WAVE NEAR 15N. CONVECTIVE PRECIPITATION...
SCATTERED MODERATE TO STRONG FROM 10N TO 18N BETWEEN 65W AND
74W...SCATTERED MODERATE TO ISOLATED STRONG FROM 12N TO 17N
BETWEEN 75W AND 81W. SURFACE PRESSURES ARE LOW IN THE AREA...AND
ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BECOME CONDUCIVE FOR A
TROPICAL DEPRESSION TO FORM DURING THE NEXT FEW DAYS.  THIS
SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS THE WAVE MOVES SLOWLY WESTWARD. IT IS
LIKELY THAT HEAVY RAINS FROM THIS DISTURBANCE OR POSSIBLE
TROPICAL CYCLONE WILL SPREAD ACROSS JAMAICA...EASTERN CUBA...AND
HISPANIOLA DURING THE NEXT SEVERAL DAYS. IT IS POSSIBLE THAT
THESE RAINS MAY PRODUCE LIFE-THREATENING FLASH FLOODS AND MUD
SLIDES...ESPECIALLY NEAR AREAS OF HIGH TERRAIN.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 49W FROM 10N TO 24N. A
1009 MB LOW PRESSURE CENTER IS ALONG THE WAVE NEAR 19N. IT IS
POSSIBLE THAT UPPER LEVEL WINDS MAY BECOME A LITTLE MORE
CONDUCIVE FOR DEVELOPMENT DURING THE NEXT DAY OR SO. THIS SYSTEM
HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD ABOUT 10 MPH.
CONVECTIVE PRECIPITATION...NEARBY SCATTERED MODERATE TO ISOLATED
STRONG FROM 19N TO 24N BETWEEN 47W AND 54W PROBABLY IS MORE
RELATED TO THE NEARBY 29N49W UPPER LEVEL CYCLONIC CIRCULATION
CENTER THAN TO THE WAVE AND THE 1009 MB LOW PRESSURE CENTER.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 60W/61W FROM 12N TO
22N. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION ACCOMPANIES
THE TROPICAL WAVE.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SENEGAL NEAR 13N17W TO
11N21W 11N30W AND 7N40W. THE ITCZ IS NON-EXISTENT DUE TO THE
TRADEWIND FLOW ELSEWHERE IN THE AREA. CONVECTIVE
PRECIPITATION...SCATTERED MODERATE TO STRONG FROM 2N TO 6N
BETWEEN 10W AND 12W...FROM 6N TO 10N BETWEEN 18W AND 22W...AND
FROM 8N TO 10N BETWEEN 33W AND 40W...SCATTERED MODERATE TO
ISOLATED STRONG ELSEWHERE FROM 2N TO 12N TO THE EAST OF 50W.

...DISCUSSION...

FROM THE WESTERN ATLANTIC OCEAN...ACROSS SOUTH FLORIDA...INTO
THE FLORIDA STRAITS AND THE YUCATAN CHANNEL...REACHING THE
NORTHWESTERN CORNER OF THE CARIBBEAN SEA...AND THE REST OF THE
GULF OF MEXICO...

A DEEP LAYER TROUGH PASSES THROUGH THE ATLANTIC OCEAN NEAR
32N75W...ACROSS THE NORTHERN BAHAMAS...TO 24N80W JUST TO THE
EAST OF SOUTH FLORIDA...INTO THE NORTHWESTERN CORNER OF THE
CARIBBEAN SEA NEAR 16N86W. THE TROUGH SUPPORTS THE COLD FRONT
THAT PASSES THROUGH 32N70W...ACROSS THE NORTHERN BAHAMAS TO
25N79W. THE COLD FRONT STARTS TO DISSIPATE FROM 25N79W...
THROUGH THE FLORIDA STRAITS TO 23N88W...CURVING TO 24N94W.
COMPARATIVELY DRIER AIR IN SUBSIDENCE IN WATER VAPOR IMAGERY
COVERS THE ENTIRE GULF OF MEXICO...AND THE ATLANTIC OCEAN THAT
IS TO THE WEST OF THE LINE THAT PASSES THROUGH 32N71W 23N80W.

CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG
IN THE ATLANTIC OCEAN FROM 23N TO 28N BETWEEN 64W AND 72W...
NUMEROUS STRONG IN THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA
FROM HONDURAS NEAR 15N TO 20N BETWEEN 81W AND 87W. A SURFACE
TROUGH IS WITHIN 60 NM OF THE COAST OF THE YUCATAN PENINSULA AND
THE GULF OF HONDURAS. THE 24-HOUR RAINFALL TOTAL FOR TEGUCIGALPA
HONDURAS FOR THE PERIOD ENDING AT 21/0000 UTC IS 1.25 INCHES.

A SURFACE RIDGE IS IN THE GULF OF MEXICO...EXTENDING FROM
A 1017 MB HIGH PRESSURE CENTER THAT IS NEAR 29N89W TO 25N92W.
BROAD SURFACE ANTICYCLONIC WIND FLOW IS IN THE SOUTHWESTERN
CORNER OF THE GULF OF MEXICO TO THE SOUTH OF 22N TO THE WEST
OF 90W.

THE REST OF THE CARIBBEAN SEA...

MIDDLE LEVEL TO UPPER LEVEL NORTHWESTERLY WIND FLOW MOVES FROM
THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO...ACROSS THE
YUCATAN PENINSULA...INTO THE NORTHWESTERN CORNER OF THE AREA AS
WESTERLY WIND FLOW. THE DIRECTIONAL COMPONENT OF THE WIND
EVENTUALLY BECOMES NORTHEASTERLY AS IT TURNS TOWARD THE
SOUTHWESTERN CORNER OF THE AREA.

BROAD UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE CARIBBEAN
SEA BETWEEN 66W AND 80W...MOVING AROUND A 17N72W UPPER LEVEL
ANTICYCLONIC CIRCULATION CENTER.

THE WIND FLOW THAT IS ON THE EASTERN SIDE OF THE AREA OF
ANTICYCLONIC WIND FLOW EVENTUALLY MERGES INTO CYCLONIC FLOW THAT
IS MOVING AROUND THE ATLANTIC OCEAN 20N49W CYCLONIC CIRCULATION
CENTER AND A RELATED TROUGH.

THE REST OF THE ATLANTIC OCEAN...

AN UPPER LEVEL TROUGH PASSES THROUGH 32N33W TO 28N41W AND
25N49W...TO A 20N49W CYCLONIC CIRCULATION CENTER...TO
14N55W...TO THE BORDER OF GUYANA AND VENEZUELA NEAR 9N60W.
SCATTERED MODERATE TO ISOLATED STRONG FROM 19N TO 24N BETWEEN
47W AND 54W.

A SECOND RIDGE EXTENDS FROM A 1024 MB HIGH PRESSURE CENTER
THAT IS NEAR 42N51W TO 34N52W 29N61W AND 22N69W. A COLD FRONT
APPROACHES THE AREA FROM THE NORTH...ALONG 32N30W 31N36W
32N41W 31N45W.

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

$$
MT




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