[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 250602
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI SEP 25 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL DEPRESSION IDA AT 25/0300 UTC IS NEAR
21.3N 45.3W. IDA IS MOVING TOWARD THE NORTH-NORTHWEST...OR 330
DEGREES...4 KNOTS. THE MINIMUM CENTRAL PRESSURE IS 1007 MB. THE
MAXIMUM SUSTAINED WIND SPEEDS ARE 30 KNOTS WITH GUSTS TO 40
KNOTS. PUBLIC ADVISORIES ABOUT TROPICAL STORM IDA ARE BEING
ISSUED UNDER THE WMO HEADER WTNT35 KNHC...AND UNDER THE AWIPS
HEADER MIATCPAT5. FORECAST/ADVISORIES ABOUT TROPICAL STORM IDA
ARE BEING ISSUED UNDER THE WMO HEADER WTNT25 KNHC...AND UNDER
THE AWIPS HEADER MIATCMAT5. CONVECTIVE PRECIPITATION...SCATTERED
STRONG WITHIN 240 NM OF THE CENTER IN THE NORTHEASTERN QUADRANT.
ISOLATED MODERATE ELSEWHERE FROM 14N TO 21N BETWEEN 40W AND 50W.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 28W FROM 16N SOUTHWARD.
IT IS DRIFTING WESTWARD. THE FORECAST FOR THE WAVE IS TO DE-
AMPLIFY AS IT MOVES INTO A RIDGE THAT IS TO THE WEST OF THE CAPE
VERDE ISLANDS. IT WILL BECOME MORE DIFFICULT TO FOLLOW IN THE
DEEP TROPICS. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM
10N TO 16N BETWEEN 19W AND 30W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF GUINEA-
BISSAU NEAR 12N15W TO 10N20W AND 10N26W. NO ITCZ IS PRESENT AT
THIS TIME. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO
STRONG FROM 07N TO 09N BETWEEN 28W AND 32W. ISOLATED MODERATE
ELSEWHERE FROM 04N TO 11N BETWEEN 23W AND 43W.

...DISCUSSION...

THE GULF OF MEXICO...

AN UPPER LEVEL TROUGH EXTENDS FROM AN INLAND GEORGIA 32N84W
CYCLONIC CIRCULATION CENTER...TO 25N83W...TO THE YUCATAN
CHANNEL...ACROSS THE YUCATAN PENINSULA...INTO THE ISTHMUS OF
TEHUANTEPEC OF SOUTHERN MEXICO. CONVECTIVE PRECIPITATION...
ISOLATED MODERATE TO THE WEST OF THE LINE FROM 29N90W TO 28N86W
TO 25N83W TO 23N88W TO THE NORTHWESTERN CORNER OF THE YUCATAN
PENINSULA. ONE SURFACE TROUGH IS ALONG 29N83W 24N89W. A SECOND
SURFACE TROUGH IS IN THE SOUTHWESTERN CORNER OF THE AREA ALONG
24N97W 20N94W.

FROM THE WESTERN ATLANTIC OCEAN...INTO THE NORTHWESTERN CORNER
OF THE CARIBBEAN SEA...

AN UPPER LEVEL RIDGE IS ALONG 32N76W...TO THE BAHAMAS NEAR
26N77W...ACROSS EASTERN SECTIONS OF CUBA...TO WESTERN SECTIONS
OF JAMAICA...TO COSTA RICA. A WARM FRONT PASSES THROUGH 32N78W
TO A 1012 MB LOW PRESSURE CENTER THAT IS NEAR 32N79W. A SURFACE
TROUGH CONTINUES FROM THE 1012 MB LOW PRESSURE CENTER TO LAKE
OKEECHOBEE IN SOUTH FLORIDA. CONVECTIVE PRECIPITATION...WIDELY
SCATTERED MODERATE TO ISOLATED STRONG FROM CUBA NORTHWARD
BETWEEN 73W AND THE STRAITS OF FLORIDA. A SURFACE TROUGH IS
ALONG 21N83W 18N85W 15N85W. WIDELY SCATTERED TO SCATTERED
MODERATE AND ISOLATED STRONG FROM 15N NORTHWARD FROM 80W
WESTWARD IN THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA.

THIS SYSTEM IS NOT EXPECTED TO DEVELOP DURING THE NEXT FEW
DAYS...AS IT MOVES NORTHWESTWARD ACROSS CENTRAL AMERICA AND THE
YUCATAN PENINSULA. A SURFACE LOW PRESSURE CENTER IS FORECAST TO
DEVELOP WITH THIS WEATHER SYSTEM...ONCE THE SYSTEM REACHES THE
SOUTHERN GULF OF MEXICO ON SUNDAY. IT IS LIKELY THAT
ENVIRONMENTAL CONDITIONS ARE GOING TO BE ONLY SOMEWHAT CONDUCIVE
FOR THE FORMATION OF A TROPICAL CYCLONE EARLY NEXT WEEK...WHILE
THE LOW PRESSURE CENTER IS MOVING NORTHWARD THROUGH THE GULF OF
MEXICO.

THE 24-HOUR RAINFALL TOTALS IN INCHES FOR THE PERIOD ENDING AT
25/0000 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...ARE 0.95 IN
NASSAU IN THE BAHAMAS...AND 0.01 IN TEGUCIGALPA IN HONDURAS.

THE REST OF THE CARIBBEAN SEA...

AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 27N67W.
CYCLONIC WIND FLOW THAT IS MOVING AROUND THE CENTER COVERS THE
CARIBBEAN SEA AND THE ATLANTIC OCEAN FROM 10N TO 32N BETWEEN 55W
AND 73W...IN THE ATLANTIC OCEAN AND IN THE CARIBBEAN SEA.
CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 18N TO 19N
BETWEEN 71W AND THE WINDWARD PASSAGE.

UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE REST OF THE
CARIBBEAN SEA...WITH THE ATLANTIC OCEAN-TO-NORTHWESTERN
CARIBBEAN SEA-TO-COSTA RICA RIDGE.

THE MONSOON TROUGH IS ALONG 10N/11N BETWEEN 73W IN COLOMBIA AND
BEYOND 85W/86W IN COSTA RICA. CONVECTIVE PRECIPITATION...
SCATTERED STRONG IN WESTERN PANAMA.

...HISPANIOLA...

UPPER LEVEL NORTHWESTERLY WIND FLOW CROSSES HISPANIOLA...
DIRECTLY RELATED TO THE 27N67W CYCLONIC CIRCULATION CENTER.
CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 18N TO 19N
BETWEEN 71W AND THE WINDWARD PASSAGE.

CURRENT CONDITIONS...IN PORT-AU-PRINCE HAITI...RAINSHOWERS WITH
THUNDER WERE BEING REPORTED FOR THE LAST OBSERVATION AT 25/0200
UTC. IN THE DOMINICAN REPUBLIC...FEW LOW LEVEL CLOUDS AND A HIGH
LEVEL CLOUD CEILING ARE IN SANTO DOMINGO. SCATTERED LOW LEVEL
CLOUDS AND SCATTERED HIGH LEVEL CLOUDS ARE IN LA ROMANA. FEW LOW
LEVEL CLOUDS ARE IN PUNTA CANA. FEW CUMULONIMBUS CLOUDS AND A
LOW LEVEL CLOUD CEILING ARE IN SANTIAGO. A LOW LEVEL CLOUD
CEILING AND A HIGH LEVEL CLOUD CEILING COVER PUERTO PLATA.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT NORTHWESTERLY WIND
FLOW WILL MOVE ACROSS HISPANIOLA FOR THE NEXT 48 HOURS...BEING
ON THE EASTERN SIDE OF A CENTRAL AMERICA/SOUTHWESTERN CARIBBEAN
SEA-TO-CUBA RIDGE...AND THE 27N67W CYCLONIC CIRCULATION CENTER.
THE GFS MODEL FORECAST FOR 500 MB SHOWS THAT WESTERLY WIND FLOW
WILL COVER THE AREA AT THE START OF THE FORECAST PERIOD...AND IT
WILL CONTINUE FOR THE FIRST 24 HOURS. NORTHWESTERLY WIND FLOW
WILL COVER THE AREA FOR DAY TWO. HISPANIOLA WILL BE IN THE
MIDDLE OF THE FLOW OF AN ATLANTIC OCEAN 24N69W CYCLONIC
CIRCULATION CENTER...AND A NORTHWEST-TO-SOUTHEAST ORIENTED
CARIBBEAN SEA RIDGE. THE GFS MODEL FOR 700 MB SHOWS THAT
SOUTHERLY WIND FLOW WILL MOVE ACROSS HISPANIOLA FOR THE NEXT 48
HOURS. HISPANIOLA WILL BE ON THE WESTERN SIDE OF AN ATLANTIC
OCEAN-TO-CARIBBEAN SEA RIDGE.

THE REST OF THE ATLANTIC OCEAN...

PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS
ABOUT TROPICAL DEPRESSION IDA.

AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 27N67W.
CYCLONIC WIND FLOW THAT IS MOVING AROUND THE CENTER COVERS THE
CARIBBEAN SEA AND THE ATLANTIC OCEAN FROM 10N TO 32N BETWEEN 55W
AND 73W...IN THE ATLANTIC OCEAN AND IN THE CARIBBEAN SEA.
CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED
STRONG FROM THE NORTHERN COASTAL WATERS OF PUERTO RICO NORTHWARD
TO 32N BETWEEN 55W AND 71W IN THE ATLANTIC OCEAN. RAINSHOWERS
ARE POSSIBLE FROM 10N TO 20N BETWEEN 55W IN THE ATLANTIC OCEAN
AND 65W IN THE CARIBBEAN SEA.

AN UPPER LEVEL TROUGH EXTENDS FROM A 33N22W CYCLONIC CIRCULATION
CENTER TO 30N30W...TO A SECOND CYCLONIC CIRCULATION CENTER THAT
IS NEAR 26N40W...TO 23N44W...TO 19N45W NEAR TROPICAL STORM IDA.
CYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN WITHIN 300 NM TO
500 NM ON EITHER SIDE OF THE 33N22W-TO-19N45W TROUGH. CONVECTIVE
PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED STRONG
FROM 17N TO 30N BETWEEN 29W AND 40W...AND FROM 32N TO 33N
BETWEEN 19W AND 20W. THE PRECIPITATION THAT IS NEAR T.D. IDA IS
COVERED SEPARATELY IN THE SPECIAL FEATURES SECTION.

A SURFACE RIDGE PASSES THROUGH 36N30W TO 32N50W TO 29N61W...TO
THE NORTHERN BAHAMAS. SURFACE ANTICYCLONIC WIND FLOW COVERS THE
ATLANTIC OCEAN FROM 24N NORTHWARD BETWEEN AFRICA AND THE
BAHAMAS.

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

$$
MT
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