[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 091105
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED SEP 09 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL DEPRESSION GRACE AT 09/0900 UTC IS NEAR
14.3N 47.2W. GRACE IS MOVING TOWARD THE WEST...OR 270 DEGREES...
15 KNOTS. THE MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 25 KNOTS WITH GUSTS TO 35 KNOTS.
PUBLIC ADVISORIES ABOUT TROPICAL DEPRESSION GRACE ARE BEING
ISSUED UNDER THE WMO HEADER WTNT32 KNHC...AND UNDER THE AWIPS
HEADER MIATCPAT2. FORECAST/ADVISORIES ABOUT TROPICAL DEPRESSION
GRACE ARE BEING ISSUED UNDER THE WMO HEADER WTNT22 KNHC...AND
UNDER THE AWIPS HEADER MIATCMAT2. CONVECTIVE PRECIPITATION...
WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 13N TO 15N
BETWEEN 45W AND 49W.

THE CENTER OF TROPICAL DEPRESSION EIGHT AT 09/0900 UTC IS NEAR
30.9N 61.4W...OR ABOUT 190 NM TO THE EAST-SOUTHEAST OF BERMUDA.
THE TROPICAL DEPRESSION IS STATIONARY FOR THE MOMENT. THE
MINIMUM CENTRAL PRESSURE IS 1011 MB. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 30 KNOTS WITH GUSTS TO 40 KNOTS. PUBLIC ADVISORIES
ABOUT TROPICAL DEPRESSION EIGHT ARE BEING ISSUED UNDER THE WMO
HEADER WTNT33 KNHC...AND UNDER THE AWIPS HEADER MIATCPAT3.
FORECAST/ADVISORIES ABOUT TROPICAL DEPRESSION GRACE ARE BEING
ISSUED UNDER THE WMO HEADER WTNT23 KNHC...AND UNDER THE AWIPS
HEADER MIATCMAT3. CONVECTIVE PRECIPITATION...SCATTERED TO
NUMEROUS STRONG FROM 29.5N TO 32.5N BETWEEN 57W AND 60W.
ISOLATED MODERATE ELSEWHERE FROM 25N TO 30N BETWEEN 55W AND 74W.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 24W/25W FROM 21N
SOUTHWARD...MOVING WESTWARD 10 TO 15 KNOTS...ACROSS THE CAPE
VERDE ISLANDS. THIS POSITION IS A MEAN POSITION THAT IS BASED ON
SATELLITE IMAGERY AND THE 700 MB WIND FIELD. CONVECTIVE
PRECIPITATION...WIDELY SCATTERED TO SCATTERED MODERATE AND
ISOLATED STRONG FROM 13N TO 16N BETWEEN 24W AND 29W. BROKEN
MULTILAYERED CLOUD AND RAINSHOWERS ARE POSSIBLE ELSEWHERE FROM
10N TO 26N BETWEEN AFRICA AND 36W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 56W/57W FROM 17N
SOUTHWARD...MOVING WESTWARD 15 KNOTS. CONVECTIVE
PRECIPITATION...NUMEROUS STRONG FROM 10N TO 11.5N BETWEEN 59W
AND 61W. WARMING CLOUD TOP TEMPERATURES AND WEAKENING BUT
POSSIBLY STILL LINGERING PRECIPITATION ELSEWHERE FROM 11N TO 13N
BETWEEN 55W AND 60W.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 69W FROM 17N SOUTHWARD...
MOVING WESTWARD 15 KNOTS. CONVECTIVE PRECIPITATION...ISOLATED
MODERATE FROM 14N TO 15N BETWEEN 70W AND 72W. RAINSHOWERS ARE
POSSIBLE ELSEWHERE FROM 16N SOUTHWARD TO VENEZUELA AND COLOMBIA
BETWEEN 66W AND 72W.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 84W/85W FROM 20N
SOUTHWARD...THROUGH EASTERN HONDURAS AND CENTRAL NICARAGUA...TO
COSTA RICA. THE WAVE IS MOVING WESTWARD 10 TO 15 KNOTS.
CONVECTIVE PRECIPITATION...ISOLATED STRONG IN INDIVIDUAL
CLUSTERS FROM THE GULF OF URABA OF COLOMBIA TO THE PANAMA COAST
ALONG 80W AND ALONG 81W...TO THE COASTAL WATERS OF COSTA RICA
AND NICARAGUA FROM 10N TO 11.5N BETWEEN 82W AND 83W. ISOLATED
MODERATE IN NORTHEASTERN NICARAGUA.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF SENEGAL
NEAR 15N17W TO THE 24W/25W TROPICAL WAVE ALONG 12N...TO 10N30W
AND 10N41W. NO ITCZ IS PRESENT AT THIS MOMENT. THE ITCZ IS BEING
BROKEN UP BY TROPICAL DEPRESSION GRACE AND THE 56W/57W TROPICAL
WAVE. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 02N TO
07N BETWEEN 09W AND 183W. ISOLATED MODERATE ELSEWHERE FROM 08N
TO 11N BETWEEN 20W AND 53W.

...DISCUSSION...

THE GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
NEAR 27N92W. CYCLONIC WIND FLOW COVERS THE GULF OF MEXICO.
CONVECTIVE PRECIPITATION...RAINSHOWERS ARE POSSIBLE TO THE EAST
OF THE LINE THAT RUNS FROM 18N94W 20N93W 26N96W 29N91W.
SCATTERED TO NUMEROUS STRONG IS IN THE ATLANTIC OCEAN FROM 29N
TO 32N BETWEEN 78W AND 80W IN THE COASTAL WATERS FROM FLORIDA TO
SOUTH CAROLINA.

THE SURFACE PRESSURE GRADIENT IN THE GULF OF MEXICO IS
COMPARATIVELY WEAK. A WEAK RIDGE EXTENDS FROM A 1018 MB HIGH
PRESSURE CENTER THAT IS NEAR 30N72W...ACROSS CENTRAL FLORIDA...
TO THE MEXICO GULF COAST NEAR 23N98W.

THE CARIBBEAN SEA...

AN INVERTED TROUGH IS ALONG 70W FROM 16N SOUTHWARD TO THE COAST
OF NORTHWESTERN VENEZUELA. THIS TROUGH IS CLOSE TO THE AREA OF
THE 69W TROPICAL WAVE. CONVECTIVE PRECIPITATION...ISOLATED
MODERATE FROM 14N TO 15N BETWEEN 70W AND 72W. RAINSHOWERS ARE
POSSIBLE ELSEWHERE FROM 16N SOUTHWARD TO VENEZUELA AND COLOMBIA
BETWEEN 66W AND 72W.

UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE AREA FROM 72W
WESTWARD. BROKEN TO OVERCAST MULTILAYERED CLOUDS COVER THE
CARIBBEAN SEA FROM 77W WESTWARD. A RIDGE EXTENDS FROM THE
SOUTHWESTERN CORNER OF THE CARIBBEAN SEA...NORTHWESTWARD...TO
THE YUCATAN CHANNEL AND WESTERN CUBA. MIDDLE LEVEL TO UPPER
LEVEL SOUTHEASTERLY WIND FLOW COVERS THE CARIBBEAN SEA FROM 80W
EASTWARD...WITH COMPARATIVELY DRIER AIR IN SUBSIDENCE.
CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 16N NORTHWARD
FROM 84W WESTWARD.

THE MONSOON TROUGH IS ALONG 08N/09N BETWEEN 73W IN COLOMBIA AND
83W NEAR COSTA RICA AND PANAMA. CONVECTIVE PRECIPITATION...
ISOLATED STRONG IN INDIVIDUAL CLUSTERS FROM THE GULF OF URABA OF
COLOMBIA TO THE PANAMA COAST ALONG 80W AND ALONG 81W...TO THE
COASTAL WATERS OF COSTA RICA AND NICARAGUA FROM 10N TO 11.5N
BETWEEN 82W AND 83W.

THE 24-HOUR RAINFALL TOTALS IN INCHES FOR THE PERIOD ENDING AT
09/0000 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...ARE 0.12 IN
CURACAO.

...HISPANIOLA...

AN UPPER LEVEL TROUGH PASSES THROUGH THE ATLANTIC OCEAN NEAR
26N63W...REACHING THE EASTERN SECTIONS OF THE DOMINICAN REPUBLIC
NEAR 19N70W. UPPER LEVEL NORTHWESTERLY WIND FLOW REACHES MUCH OF
HISPANIOLA. ONLY THE EASTERNMOST PART OF THE ISLAND IS OBSERVING
UPPER LEVEL WESTERLY WIND FLOW. 600 MB-TO-800 MB LEVEL EASTERLY
WIND FLOW ALSO IS MOVING ACROSS HISPANIOLA. CONVECTIVE
PRECIPITATION...SCATTERED STRONG FROM 17N TO 19N BETWEEN 73W AND
75W IN SOUTHWESTERN HAITI AND SURROUNDING COASTAL WATERS.

CURRENT CONDITIONS...IN THE DOMINICAN REPUBLIC...FEW LOW LEVEL
CLOUDS ARE IN SANTO DOMINGO...PUNTA CANA...AND IN SANTIAGO. FEW
LOW LEVEL CLOUDS AND SCATTERED HIGH LEVEL CLOUDS ARE IN PUERTO
PLATA.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT THE CURRENT TROUGH
THAT IS IN THE EASTERN SECTIONS OF HISPANIOLA REMAINS ACROSS THE
EASTERN SECTIONS OF THE ISLAND FOR THE WHOLE 48 HOUR FORECAST
PERIOD. THAT MEANS MOSTLY NORTHERLY WIND FLOW ON THE WESTERN
SIDE OF THE TROUGH...AND SOUTHWESTERLY WIND FLOW ON THE EASTERN
SIDE OF THE TROUGH. THE GFS MODEL FORECAST FOR 500 MB SHOWS THAT
AN ANTICYCLONIC CIRCULATION CENTER WILL BE BETWEEN ANDROS ISLAND
IN THE BAHAMAS AND SOUTH FLORIDA. A RIDGE WILL EXTEND FROM THE
ANTICYCLONIC CIRCULATION CENTER TO HISPANIOLA FOR THE FIRST 24
HOURS OF THE 48-HOUR FORECAST PERIOD. THE RIDGE WILL MOVE
WESTWARD...BRINGING NORTHEASTERLY WIND FLOW ACROSS THE AREA FOR
THE REST OF THE FORECAST TIME. THE GFS MODEL FOR 700 MB SHOWS
THAT NORTHEAST-TO-EAST WIND FLOW WILL PASS ACROSS THE AREA FOR
THE FIRST 12 TO 18 HOURS...FOLLOWED BY TIME PERIODS OF EAST-TO-
SOUTHEAST WIND FLOW.

THE ATLANTIC OCEAN...

PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS
ABOUT TROPICAL DEPRESSION GRACE AND TROPICAL DEPRESSION EIGHT.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N44W TO A
24N52W CYCLONIC CIRCULATION CENTER...TO 19N54W. A STATIONARY
FRONT PASSES THROUGH 32N29W TO 31N34W...TO 31N41W 28N47W...AND
TO 29N54W. CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE
TO ISOLATED STRONG WITHIN 360 NM TO THE NORTH OF THE LINE THAT
PASSES THROUGH 32N26W 27N32W 21N51W.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N23W TO
24N30W TO 20N34W. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS
WITHIN 150 NM ON EITHER SIDE OF THE TROUGH.

A SURFACE RIDGE PASSES THROUGH THE MADEIRA ARCHIPELAGO TO A 1019
MB HIGH PRESSURE CENTER THAT IS NEAR 27N30W TO 26N50W.

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

$$
MT
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