[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT OCT 20 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.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 12N32W 9N35W 6N36W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION
ALSO IS NEAR THE MONSOON TROUGH/ITCZ FROM 5N TO 12N BETWEEN 30W
AND 40W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 21N52W 17N53W 13N54W.
THIS WAVE IS MOVING THROUGH THE AREA OF THE 21N52W 18N52W 8N59W
MIDDLE LEVEL TO UPPER LEVEL ATLANTIC OCEAN TROUGH.
ISOLATED MODERATE CONVECTIVE PRECIPITATION IS FROM 15N TO 20N
BETWEEN 50W AND 55W.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 69W/70W...FROM THE
SOUTHEASTERN CORNER OF THE DOMINICAN REPUBLIC...TO THE
NORTHWESTERN CORNER OF VENEZUELA. SCATTERED MODERATE TO STRONG
CONVECTIVE PRECIPITATION COVERS THE AREA FROM VENEZUELA TO
SOUTHWESTERN COASTAL PUERTO RICO AND HISPANIOLA BETWEEN 65W
AND 74W. THE 24-HOUR RAINFALL TOTAL IN INCHES FOR GUADELOUPE
FOR THE PERIOD ENDING AT 20/0000 UTC IS 0.69.

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

THE MONSOON TROUGH PASSES THROUGH COASTAL GUINEA-BISSAU NEAR
12N16W TO 9N20W 9N29W 6N34W AND 6N38W. THE ITCZ CONTINUES FROM
6N38W TO 9N46W AND 10N60W. CONVECTIVE PRECIPITATION...SCATTERED
MODERATE TO STRONG WITHIN 60 TO 90 NM ON EITHER SIDE OF 12N16W
11N25W 9N33W AND FROM 6N TO 8N BETWEEN 19W AND 21W...WIDELY
SCATTERED TO SCATTERED MODERATE AND ISOLATED STRONG ELSEWHERE
FROM 3N TO 12N TO THE EAST OF 43W.

...DISCUSSION...

FROM THE WESTERN ATLANTIC OCEAN INTO THE GULF OF MEXICO...
AND THE REST OF THE GULF OF MEXICO...

A DEEP LAYER TROUGH PASSES THROUGH THE GREAT LAKES REGION OF THE
U.S.A....THROUGH THE SOUTHEASTERN U.S.A....INTO THE CENTRAL AND
WEST CENTRAL GULF OF MEXICO. THE TROUGH SUPPORTS A COLD FRONT
THAT PASSES THROUGH 32N77W IN THE ATLANTIC OCEAN...TO 27N81W IN
FLORIDA...TO 25N90W IN THE CENTRAL GULF OF MEXICO...TO 23N98W
ALONG THE MEXICO COAST. COMPARATIVELY DRIER AIR IN SUBSIDENCE
IN WATER VAPOR IMAGERY IS TO THE NORTH AND NORTHWEST OF THE LINE
THAT PASSES THROUGH 32N78W...INTO THE CENTRAL GULF OF MEXICO...
TO THE LOWER TEXAS GULF COAST.

BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS
ARE WITHIN 60 TO 90 NM ON EITHER SIDE OF THE LINE THAT PASSES
THROUGH 32N77W IN THE ATLANTIC OCEAN...TO 28N82W IN FLORIDA...
TO 25N90W IN THE CENTRAL GULF OF MEXICO...TO 25N97W IN EXTREME
NORTHEASTERN COASTAL MEXICO. OTHER BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND POSSIBLE PRECIPITATION ARE ALONG THE
MEXICO COAST AND IN COASTAL PLAINS FROM 20N TO 23N BETWEEN 95W
AND 99W.

CONVECTIVE PRECIPITATION THAT IS TO THE EAST OF THE COLD FRONT
AND THE DEEP LAYER TROUGH...ISOLATED TO WIDELY SCATTERED MODERATE
TO THE NORTH OF 20N TO THE WEST OF 65W.

THE CARIBBEAN SEA...

MIDDLE LEVEL TO UPPER LEVEL WIND FLOW MOVES FROM THE
SOUTHWESTERN CORNER OF THE GULF OF MEXICO...ACROSS THE YUCATAN
PENINSULA...INTO THE NORTHWESTERN CORNER OF THE AREA. THE
DIRECTIONAL COMPONENT OF THE WIND EVENTUALLY CHANGES SLIGHTLY
TO WESTERLY AND SOUTHWESTERLY AS THE WIND MOVES FROM THE YUCATAN
PENINSULA THROUGH THE WINDWARD PASSAGE. THE SOUTHWESTERLY WIND
FLOW THAT MOVES THROUGH THE WINDWARD PASSAGE EVENTUALLY MERGES
INTO THE LONGER WAVE LARGER-SCALE TROUGH THAT SUPPORTS THE GULF
OF MEXICO COLD FRONT. THE WIND FLOW THAT DOES NOT MERGE INTO THE
TROUGH AREA BECOMES PART OF AN AREA OF MIDDLE LEVEL TO UPPER
LEVEL ANTICYCLONIC WIND FLOW WITH A MEAN CENTER NEAR 16N70W.
PART OF THE WIND THAT IS TO THE EAST OF 67W EVENTUALLY MERGES
INTO CYCLONIC FLOW THAT IS MOVING AROUND AN ATLANTIC OCEAN
18N52W CYCLONIC CIRCULATION CENTER AND A RELATED TROUGH.
THE MIDDLE LEVEL TO UPPER LEVEL WIND FLOW THAT IS IN THE
SOUTHWESTERN CORNER OF THE AREA IS LARGELY
EASTERLY-TO-NORTHEASTERLY.

A TROPICAL WAVE IS ALONG 69W/70W...FROM THE SOUTHEASTERN CORNER
OF THE DOMINICAN REPUBLIC...TO THE NORTHWESTERN CORNER OF
VENEZUELA. SCATTERED MODERATE TO STRONG CONVECTIVE PRECIPITATION
COVERS THE AREA FROM VENEZUELA TO SOUTHWESTERN COASTAL PUERTO
RICO AND HISPANIOLA BETWEEN 65W AND 74W. THE 24-HOUR RAINFALL
TOTAL IN INCHES FOR GUADELOUPE FOR THE PERIOD ENDING AT
20/0000 UTC IS 0.69.

A SURFACE TROUGH IS ALONG 82W/83W FROM 11N TO 20N. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION IS FROM
12N TO 17N BETWEEN 78W AND 83W...AND IN THE NORTHWESTERN CORNER
OF THE AREA FROM 16N AT THE HONDURAS COAST TO 21N NEAR CUBA
BETWEEN 80W AND 86W. THE 24-HOUR RAINFALL TOTAL IN INCHES FOR
TEGUCIGALPA HONDURAS FOR THE PERIOD ENDING AT 20/0000 UTC IS
0.31.

THE REST OF THE ATLANTIC OCEAN...

AN UPPER LEVEL SHEAR AXIS PASSES THROUGH 33N43W TO 26N50W TO
21N52W...BECOMING A TROUGH FROM 21N52W TO AN 18N52W ATLANTIC
OCEAN MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER. THE
TROUGH CONTINUES FROM 18N52W TO 13N52W AND 8N59W ALONG THE
COAST OF GUYANA. MIDDLE LEVEL TO UPPER LEVEL NORTHERLY WIND
FLOW THAT IS IN THE ATLANTIC OCEAN BETWEEN THE SHEAR AXIS AND
61W EVENTUALLY FEEDS INTO THE LARGER-SCALE CYCLONIC WIND FLOW
AROUND THE WHOLE SYSTEM. CONVECTIVE PRECIPITATION...SCATTERED
STRONG FROM 20N TO 23N BETWEEN 45W AND 49W...ISOLATED MODERATE
TO LOCALLY STRONG FROM 16N TO 20N BETWEEN 36W AND 55W...
RAINSHOWERS ARE POSSIBLE FROM 26N TO 28N BETWEEN 61W AND 63W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE
DETAILS ABOUT 20 KNOT WINDS AND 8 FOOT SEA HEIGHTS...FROM
19N TO 24N TO THE EAST OF 47W FOR THE NEXT 6 HOURS OR SO...
AND IN 42 HOURS OR SO TO THE NORTH OF A COLD FRONT 31N44W
29N35W...THAT MOVES TO 31N46W 28N35W IN 48 HOURS.

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

$$
MT





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