[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 300004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT AUG 29 2015

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

TROPICAL STORM ERIKA WEAKENED...AND THE REMNANTS OF ERIKA ARE A
1012 MB LOW PRESSURE CENTER THAT IS NEAR 22N77.5W ALONG THE
ATLANTIC OCEAN SIDE COAST OF CUBA. THE LOW CENTER IS FORECAST TO
DISSIPATE DURING THE NEXT 24 HOURS...LEAVING A SURFACE TROUGH IN
THE EASTERN GULF OF MEXICO. CONVECTIVE PRECIPITATION...NUMEROUS
STRONG IS INLAND IN CUBA BETWEEN 78W AND 82W...AND IN THE
COASTAL PLAINS OF CUBA ON THE COAST THAT FACES THE STRAITS OF
FLORIDA BETWEEN 82W AND 85W. SIMILAR STRONG CONVECTIVE
PRECIPITATION IS IN THE CARIBBEAN SEA FROM 19N TO 20N BETWEEN
78W AND 79W. THE LAST PUBLIC ADVISORY ABOUT ERIKA WAS ISSUED BY
THE NHC AT 29/1330 UTC.

GALE-FORCE WINDS ARE PRESENT FROM 21N TO 24N BETWEEN 75.5W AND
77.5W...WITH THE REMNANTS OF ERIKA. EXPECT SEA HEIGHTS TO RANGE
FROM 8 FEET TO 12 FEET. ELSEWHERE S OF 26N BETWEEN 74W AND 79W E
TO SE WINDS 20 TO 30 KT. SEAS 8 TO 11 FT.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 16W FROM 16N IN
NORTHERN SENEGAL SOUTHWARD. A 1008 MB LOW PRESSURE CENTER IS
ALONG THE WAVE NEAR 10N. CONVECTIVE PRECIPITATION...SCATTERED
STRONG FROM 09N TO 15N BETWEEN 16W AND 20W. THE CHANCE THAT THIS
FEATURE MAY DEVELOP INTO A TROPICAL CYCLONE DURING THE NEXT 48
HOURS IS HIGH.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 45W/46W FROM 18N
SOUTHWARD. THE WAVE IS MOVING WESTWARD 15 TO 20 KNOTS. A 1012 MB
LOW PRESSURE CENTER IS NEAR 13N46W. CONVECTIVE PRECIPITATION...
WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 09N TO 14N
BETWEEN 47W AND 54W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND
OTHER POSSIBLE RAINSHOWERS COVER THE ATLANTIC OCEAN ELSEWHERE
FROM 08N TO 20N BETWEEN 40W AND 50W...AND FROM 08N TO 15N
BETWEEN 50W AND 55W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 57W/58W FROM 20N
SOUTHWARD. THE WAVE IS MOVING WESTWARD 10 TO 15 KNOTS.
CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 12N TO 19N
BETWEEN 58W AND 64W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH IS ALONG 10N18W 08N31W 13N44W. THE ITCZ IS
ALONG 12N BETWEEN 47W AND 57W. CONVECTIVE PRECIPITATION...WIDELY
SCATTERED MODERATE TO ISOLATED STRONG FROM 06N TO 10N BETWEEN
18W AND 32W. ISOLATED MODERATE FROM 11N TO 13N BETWEEN 54W AND
58W.

...DISCUSSION...

THE GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM A CYCLONIC
CIRCULATION CENTER THAT IS NEAR SOUTHEASTERN LOUISIANA/COASTAL
MISSISSIPPI...INTO THE SOUTH CENTRAL GULF OF MEXICO...TOWARD THE
SOUTHWESTERN CORNER OF THE GULF OF MEXICO. A SURFACE TROUGH IS
ALONG 31N88W 28N89W 26N93W. COMPARATIVELY DRIER AIR IN
SUBSIDENCE IS APPARENT IN WATER VAPOR IMAGERY TO THE WEST AND
NORTHWEST OF THE LINE 30N87W 26N86W 23N90W 21N97W. CONVECTIVE
PRECIPITATION...SCATTERED TO NUMEROUS STRONG WITHIN 30 NM TO 60
NM ON EITHER SIDE OF THE LINE FROM 24N84W IN THE GULF OF
MEXICO...27N82W IN CENTRAL FLORIDA...30N82W IN NORTHEASTERN
FLORIDA. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND OTHER
POSSIBLE RAINSHOWERS ARE TO THE EAST OF THE 30N87W 21N97W LINE.
IN THE ATLANTIC OCEAN...WIDELY SCATTERED MODERATE TO ISOLATED
STRONG TO THE NORTHWEST OF THE LINE FROM 26N80W BEYOND 32N70W.

THE CARIBBEAN SEA...

A MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH IS ALONG 73W/74W
FROM THE COAST OF HAITI TO 12N. CYCLONIC WIND FLOW THAT IS
MOVING AROUND THE INVERTED TROUGH COVERS THE CARIBBEAN SEA
BETWEEN 71W AND 77W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND
POSSIBLE RAINSHOWERS ARE ELSEWHERE FROM 14N TO 23N BETWEEN 67W
AND 76W. THIS AREA COVERS HISPANIOLA...PARTS OF THE BAHAMAS...
AND  AND EASTERN CUBA.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM EASTERN
VENEZUELA NEAR 07N61W TO 09N59W TO 12N55W.

OTHER CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED
STRONG FROM 16N TO 17N BETWEEN 82W AND 83W. ISOLATED MODERATE IN
THE SOUTHWESTERN CORNER OF THE AREA FROM 12N SOUTHWARD FROM 80W
WESTWARD.

THE 24-HOUR RAINFALL TOTALS IN INCHES FOR THE PERIOD ENDING AT
29/1200 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...ARE 3.00 IN
VERACRUZ MEXICO...0.98 IN FREEPORT IN THE BAHAMAS...0.33 IN
TEGUCIGALPA IN HONDURAS...0.11 IN MERIDA MEXICO...0.09 IN NASSAU
IN THE BAHAMAS...AND 0.02 IN GUADELOUPE.

...HISPANIOLA...

ERIKA HAS WEAKENED...AND THE REMNANT LOW PRESSURE CENTER OF
ERIKA IS ALONG THE COAST OF CUBA NEAR 22N77.5W. IT IS POSSIBLE
THAT RAINFALL ACCUMULATIONS OF 3 TO 6 INCHES...WITH MAXIMUM
VALUES OF 10 INCHES...MAY SPREAD ACROSS SECTIONS OF THE
DOMINICAN REPUBLIC AND HAITI THROUGH SUNDAY. IT IS POSSIBLE THAT
THESE RAINS MAY CAUSE LIFE-THREATENING FLASH FLOODS AND MUD
SLIDES.

OBSERVATIONS...IN HAITI...A CLOUD CEILING AT 6000 FEET IN PORT-
AU-PRINCE. FOR THE DOMINICAN REPUBLIC...FEW CUMULONIMBUS CLOUDS
AND A MIDDLE LEVEL CLOUD CEILING AND A HIGH LEVEL CLOUD CEILING
ARE IN BARAHONA. FEW CUMULONIMBUS CLOUDS...SCATTERED LOW LEVEL
CLOUDS AND SCATTERED MIDDLE LEVEL CLOUDS...AND A HIGH LEVEL
CLOUD CEILING ARE IN SANTO DOMINGO. SCATTERED LOW LEVEL CLOUDS
AND A MIDDLE LEVEL CLOUD CEILING ARE IN LA ROMANA AND PUNTA
CANA. FEW CUMULONIMBUS CLOUDS...SCATTERED MIDDLE LEVEL CLOUDS...
AND A HIGH LEVEL CLOUD CEILING ARE BEING OBSERVED IN SANTIAGO.
SCATTERED LOW LEVEL CLOUDS AND A HIGH LEVEL CLOUD CEILING ARE
BEING OBSERVED IN PUERTO PLATA.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT WESTERLY WIND FLOW
WILL START ACROSS HISPANIOLA WITH AN ANTICYCLONIC CIRCULATION
CENTER OFF THE SOUTHERN COAST OF HAITI. THAT ANTICYCLONIC
CIRCULATION CENTER WILL MOVE NORTHWESTWARD AND DISSIPATE...
GIVING NORTHERLY WIND FLOW TO HISPANIOLA FOR THE NEXT 12 TO 18
HOURS. WESTERLY WIND FLOW WILL DEVELOP ACROSS HISPANIOLA AS A
CYCLONIC CIRCULATION CENTER MOVES TO THE AREA OF THE
SOUTHEASTERN BAHAMAS. WESTERLY WIND FLOW WILL CONTINUE ACROSS
HISPANIOLA FOR THE NEXT 18 HOURS OR SO...WITH THE CYCLONIC
CENTER STILL TO THE NORTH OF HAITI. SOUTHWESTERLY WIND FLOW WILL
COVER HISPANIOLA BY THE END OF THE 48-HOUR FORECAST PERIOD AS
THE CYCLONIC CENTER MOVES INTO THE WINDWARD PASSAGE. THE GFS
MODEL FORECAST FOR 500 MB SHOWS THAT A MIDDLE LEVEL INVERTED
TROUGH WILL BE ALONG 74W/75W...BRINGING SOUTHEASTERLY WIND FLOW
TO THE AREA. THE INVERTED TROUGH WILL MOVE WESTWARD TO 81W/82W
IN 24 HOURS...STILL BRINGING SOUTHEASTERLY WIND FLOW TO
HISPANIOLA. THE INVERTED TROUGH WILL MOVE TO 85W/86W BY 48
HOURS...STILL BRINGING EAST TO SOUTHEAST WIND FLOW TO
HISPANIOLA. THE GFS MODEL FORECAST FOR 700 MB SHOWS THAT
SOUTHEASTERLY WIND FLOW WILL MOVE ACROSS THE AREA FOR THE NEXT
48 HOURS.

THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N25W TO
28N26W 25N28W 23N36W AND 24N40W. A SHEAR AXIS CONTINUES FROM
24N40W TO 26N44W. A SECOND TROUGH CONTINUES FROM 26N44W TO
26N49W...TO A 24N55W CYCLONIC CIRCULATION CENTER. CYCLONIC WIND
FLOW THAT IS MOVING AROUND THE 24N55W CENTER COVERS THE ATLANTIC
OCEAN FROM 17N TO 29N BETWEEN 47W AND 64W. A SURFACE TROUGH IS
ALONG 31N47W 28N51W 27N55W. CONVECTIVE PRECIPITATION...WIDELY
SCATTERED MODERATE TO ISOLATED STRONG TO THE NORTH OF THE LINE
28N37W 25N50W 21N64W 23N70W.

A 1022 MB HIGH PRESSURE CENTER IS NEAR 31N67W. A SURFACE RIDGE
EXTENDS FROM THE 1022 MB CENTER TO PUERTO RICO. ANTICYCLONIC
WIND FLOW ALSO COVERS THE ATLANTIC OCEAN FROM 26N NORTHWARD
BETWEEN 58W AND 80W.

A SURFACE RIDGE IS ALONG 28N22W...TO 25N32W...TO A 1021 MB HIGH
PRESSURE CENTER THAT IS NEAR 24N41W...TO A SECOND 1021 MB HIGH
PRESSURE CENTER THAT IS NEAR 24N49W...TO 24N58W.

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

$$
MT
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