Tropical Weather Discussion
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000
AXNT20 KNHC 310005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN AUG 30 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...

THE CENTER OF TROPICAL STORM FRED AT 30/2100 UTC IS NEAR 14.4N
21.3W...OR ABOUT 130 NM TO THE EAST OF PRAIA IN THE CAPE VERDE
ISLANDS. A HURRICANE WARNING HAS BEEN ISSUED FOR THE CAPE VERDE
ISLANDS. A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA...IN THIS CASE WITHIN
THE NEXT 12 TO 24 HOURS. PREPARATIONS IN ORDER TO PROTECT LIFE
AND PROPERTY SHOULD BE RUSHED TO COMPLETION. FRED IS MOVING
TOWARD THE NORTHWEST...OR 310 DEGREES...14 KNOTS. THE MINIMUM
CENTRAL PRESSURE IS 998 MB. THE MAXIMUM SUSTAINED WIND SPEEDS
ARE 55 KNOTS WITH GUSTS TO 65 KNOTS. PUBLIC ADVISORIES ABOUT
TROPICAL STORM FRED ARE BEING ISSUED UNDER THE WMO HEADER
WTNT31 KNHC...AND UNDER THE AWIPS HEADER MIATCPAT1. FORECAST/
ADVISORIES ABOUT TROPICAL STORM FRED ARE BEING ISSUED UNDER THE
WMO HEADER WTNT21 KNHC...AND UNDER THE AWIPS HEADER MIATCMAT1.
CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 13N TO 15N
BETWEEN 21W AND 23W. WIDELY SCATTERED TO SCATTERED MODERATE AND
ISOLATED STRONG ELSEWHERE FROM 10N TO 18N BETWEEN 17W AND 25W.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE CURVES FROM 20N50W TO 15N53W AND
09N54W. THE WAVE IS MOVING WESTWARD 15 KNOTS. THIS WAVE SHOWS UP
WELL IN THE 700 MB WIND FIELD. CONVECTIVE PRECIPITATION...
WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 09N TO 20N
BETWEEN 50W AND 62W IN THE CARIBBEAN SEA. BROKEN MULTILAYERED
CLOUDS AND POSSIBLE RAINSHOWERS ARE ELSEWHERE FROM 16N TO 23N
BETWEEN 46W AND 50W.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 66W/67W FROM 20N
SOUTHWARD...ACROSS PUERTO RICO...TO VENEZUELA. THE WAVE IS
MOVING WESTWARD 20 KNOTS DURING THE LAST 24 HOURS. UPPER LEVEL
ANTICYCLONIC WIND FLOW COVERS THE CARIBBEAN SEA ON TOP OF THE
TROPICAL WAVE. CONVECTIVE PRECIPITATION...BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND ISOLATED MODERATE FROM 14N TO 20N
BETWEEN 64W AND 74W. SOME OF THE PRECIPITATION IS IN THE
DOMINICAN REPUBLIC AND ALONG ITS BORDER WITH HAITI.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH IS ALONG 11N23W 08N30W 07N35W 07N41W. THE
ITCZ IS NOT PRESENT AT THIS TIME. CONVECTIVE PRECIPITATION...
WIDELY SCATTERED MODERATE TO ISOLATED STRONG IS FROM 08N TO 10N
BETWEEN 22W AND 28W. ISOLATED MODERATE FROM 05N TO 08N
BETWEEN 29W AND 40W.

...DISCUSSION...

THE GULF OF MEXICO...

UPPER LEVEL SOUTHWESTERLY WIND FLOW SPANS THE GULF OF MEXICO.
THIS WIND FLOW IS ASSOCIATED WITH BROAD UPPER LEVEL CYCLONIC
WIND FLOW...THAT IS CONNECTED WITH TWO CYCLONIC CIRCULATION
CENTERS. ONE CYCLONIC CIRCULATION CENTER IS IN NORTHWESTERN
GEORGIA/NORTHEASTERN ALABAMA. THE SECOND CYCLONIC CIRCULATION
CENTER IS IN SOUTHWESTERN TEXAS ALONG THE BORDER WITH MEXICO
NEAR 29N101W. RAINSHOWERS ARE POSSIBLE FROM 90W WESTWARD.

A SURFACE TROUGH EXTENDS FROM SOUTHEASTERN GEORGIA...THROUGH
NORTHEASTERN FLORIDA...TOWARD TAMPA...INTO THE SOUTHEASTERN GULF
OF MEXICO...THROUGH THE YUCATAN CHANNEL...CURVING INTO THE
CARIBBEAN SEA NEAR 17N83W. THIS SURFACE TROUGH REPRESENTS THE
REMNANTS OF ERIKA. CONVECTIVE PRECIPITATION...IN THE ATLANTIC
OCEAN...SCATTERED MODERATE TO STRONG FROM 30N NORTHWARD FROM 76W
WESTWARD. WIDELY SCATTERED MODERATE FROM CUBA TO 30N FROM 76W
WESTWARD. ACROSS FLORIDA...IN THE GULF OF MEXICO...IN CUBA...AND
IN THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA...ISOLATED
MODERATE TO LOCALLY STRONG FROM 15N NORTHWARD BETWEEN 76W AND
85W. SCATTERED MODERATE TO ISOLATED STRONG IN THE YUCATAN
PENINSULA.

THE CARIBBEAN SEA...

THE MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH FROM 24 HOURS
AGO THAT WAS ALONG 73W/74W NOW IS ALONG 74W/75W FROM THE 18N...
NEAR THE SOUTHERNMOST PART OF THE WINDWARD PASSAGE...SOUTHWARD.
COMPARATIVELY DRIER AIR IN SUBSIDENCE IS APPARENT IN WATER VAPOR
IMAGERY IN THE AREA OF THE INVERTED TROUGH.

UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE CARIBBEAN SEA FROM
THE INVERTED TROUGH WESTWARD TO MEXICO AND CENTRAL AMERICA.
CONVECTIVE PRECIPITATION...SCATTERED STRONG WITHIN 30 NM TO 45
NM ON EITHER SIDE OF THE LINE FROM EASTERN HONDURAS NEAR 16N85W
TO 11N86W IN NICARAGUA.

THE MONSOON TROUGH IS ALONG 09N BETWEEN 74W IN COLOMBIA AND 86W
IN COSTA RICA. CONVECTIVE PRECIPITATION...WIDELY SCATTERED
MODERATE TO ISOLATED STRONG FROM 07N TO 11N BETWEEN 72W/73W IN
NORTHEASTERN COLOMBIA AND NORTHWESTERN VENEZUELA TO 86W IN COSTA
RICA.

BROAD MIDDLE LEVEL TO UPPER LEVEL CYCLONIC WIND FLOW COVERS THE
AREA FROM 03N TO 11N BETWEEN 53W AND 65W...COVERING INTERIOR AND
COASTAL SECTIONS AND COASTAL WATERS OF SOUTH AMERICA...IN PARTS
OF BRAZIL...VENEZUELA...GUYANA...SURINAME...AND FRENCH GUIANA.

THE 24-HOUR RAINFALL TOTALS IN INCHES FOR THE PERIOD ENDING AT
30/1200 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...ARE 1.43 IN
TRINIDAD...0.29 IN SAN JUAN PUERTO RICO...0.17 IN GUADELOUPE...
0.09 IN FREEPORT IN THE BAHAMAS...0.08N IN MONTEGO BAY IN
JAMAICA...0.06 IN BERMUDA...0.05 IN KINGSTON JAMAICA...AND 0.01
IN ST. THOMAS IN THE VIRGIN ISLANDS.

...HISPANIOLA...

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 66W/67W FROM 20N
SOUTHWARD...ACROSS PUERTO RICO...TO VENEZUELA. THIS WAVE SHOULD
BE PASSING ACROSS HISPANIOLA DURING THE NEXT 12 TO 24 HOURS.

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

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT SOUTHERLY WIND FLOW
WILL MOVE ACROSS HISPANIOLA FOR THE FIRST 30 HOURS OR SO...
FOLLOWED BY SOUTHWESTERLY WIND FLOW FOR THE REST OF THE 48 HOUR
FORECAST PERIOD. THE GFS MODEL FORECAST FOR 500 MB SHOWS THAT
EAST-TO-SOUTHEAST WIND FLOW...AND AT LEAST ONE INVERTED
TROUGH...WILL MOVE ACROSS THE AREA. THE GFS MODEL FORECAST FOR
700 MB SHOWS THAT EAST-TO-SOUTHEAST WIND FLOW WILL MOVE ACROSS
THE AREA FOR THE NEXT 48 HOURS.

THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N18W TO
24N23W TO 18N37W. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION
IS APPARENT WITH THIS TROUGH.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS ALONG 31N50W 27N54W
22N60W 18N62W. A SURFACE TROUGH IS ALONG 31N47W 29N50W 26N60W
25N70W. CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO
ISOLATED STRONG TO THE NORTH OF THE LINE 26N35W 23N50W 20N60W
22N70W 24N74W 30N78W.

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

$$
MT


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