[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130600
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU AUG 13 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.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 28W/29W...FROM 17N
SOUTHWARD...MOVING WESTWARD 15 KNOTS. NO SIGNIFICANT DEEP
CONVECTIVE PRECIPITATION IS APPARENT IN SATELLITE IMAGERY.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 50W/51W FROM 15N
SOUTHWARD MOVING WESTWARD 10 KNOTS. THE WAVE COINCIDES WITH A
700 MB TROUGH. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM
10N TO 12N BETWEEN 50W AND 52W.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 78W/79W FROM WESTERN
JAMAICA TO PANAMA...MOVING WESTWARD 15 TO 20 KNOTS. THE WAVE
COINCIDES WITH A 700 MB TROUGH. NO SIGNIFICANT DEEP CONVECTIVE
PRECIPITATION IS APPARENT IN SATELLITE IMAGERY. THIS WAVE IS
MOVING THROUGH AN AREA OF LARGE-SCALE CYCLONIC WIND FLOW THAT
SPANS THE CARIBBEAN SEA.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF SENEGAL
NEAR 14N17W...TO 12N20W 12N25W 09N33W 07N39W. THE ITCZ CONTINUES
FROM 07N39W TO 07N44W 05N47W AND 06N50W. CONVECTIVE
PRECIPITATION...ISOLATED MODERATE TO LOCALLY STRONG FROM 09N TO
12N BETWEEN AFRICA AND 20W...AND FROM 06N TO 10N BETWEEN 29W AND
57W.

...DISCUSSION...

...THE GULF OF MEXICO...

LARGE-SCALE ANTICYCLONIC WIND FLOW IS SWEEPING ACROSS THE
NORTHERN HALF OF THE GULF OF MEXICO...FROM 24N NORTHWARD.

A STATIONARY FRONT PASSES THROUGH 31N80W IN THE ATLANTIC
OCEAN...THROUGH THE FLORIDA PANHANDLE...TO THE COASTAL
PLAINS/COASTAL WATERS OF ALABAMA AND MISSISSIPPI...THROUGH
SOUTHERN LOUISIANA...INTO EAST TEXAS. CONVECTIVE
PRECIPITATION...BROKEN TO OVERCAST MULTILAYERED CLOUDS AND
ISOLATED MODERATE CONVECTIVE PRECIPITATION COVER THE AREA THAT
IS FROM 27N TO 31N BETWEEN FLORIDA AND EASTERN SECTIONS OF TEXAS.

A SURFACE RIDGE PASSES ACROSS ANDROS ISLAND...THROUGH THE
STRAITS OF FLORIDA...TO A 1016 MB HIGH PRESSURE CENTER THAT IS
NEAR 24N90W...TO THE COAST OF MEXICO ALONG 24N/25N.

...THE CARIBBEAN SEA AND HISPANIOLA...

ONE MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
NEAR 19N77W BETWEEN SOUTHEASTERN CUBA AND JAMAICA. A SECOND AND
COMPARATIVELY WEAKER MIDDLE LEVEL TO UPPER LEVEL CYCLONIC
CIRCULATION CENTER IS TO THE SOUTH OF HAITI NEAR 17N72W. THESE
TWO INDIVIDUAL CYCLONIC CIRCULATION CENTERS ARE EMBEDDED IN THE
OVERALL LARGER-SCALE MIDDLE LEVEL TO UPPER LEVEL CYCLONIC WIND
FLOW THAT SPANS THE CARIBBEAN SEA. A SURFACE TROUGH IS ALONG
70W/71W FROM 13N TO 17N. CONVECTIVE PRECIPITATION...ISOLATED
MODERATE TO LOCALLY STRONG FROM 16N TO PUERTO RICO AND
HISPANIOLA BETWEEN 65W AND 74W...AND FROM 17N TO 21N BETWEEN 76W
AND 85W...AND FROM 12N TO 13N BETWEEN 82W AND 83W ALONG THE
COAST OF NICARAGUA. RAINSHOWERS ARE POSSIBLE ELSEWHERE TO THE
NORTHWEST AND NORTH OF THE LINE THAT RUNS FROM 17N64W TO 11N68W
TO 12N75W TO 09N82W.

SURFACE OBSERVATIONS FOR THE DOMINICAN REPUBLIC...FEW
CUMULONIMBUS CLOUDS AND OTHER SCATTERED LOW LEVEL CLOUDS ARE
BEING OBSERVED IN SANTO DOMINGO. FEW LOW LEVEL CLOUDS ARE IN LA
ROMANA. SCATTERED LOW LEVEL CLOUDS AND SCATTERED MIDDLE LEVEL
CLOUDS ARE IN PUNTA CANA. FEW LOW LEVEL CLOUDS AND SCATTERED
HIGH LEVEL CLOUDS ARE IN SANTIAGO. FEW LOW LEVEL CLOUDS ARE
BEING OBSERVED IN PUERTO PLATA.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT THE CURRENT 17N72W
CYCLONIC CIRCULATION CENTER WILL MOVE NORTHWESTWARD TO 20N81W.
SOUTHERLY WIND FLOW WILL COVER HISPANIOLA FOR MOST OF THE FIRST
24 HOURS OF THE 48-HOUR FORECAST PERIOD THAT STARTS ON 13/0000
UTC. THE CYCLONIC CIRCULATION CENTER EVENTUALLY WILL MOVE TO
20N81W...AND THEN IT WILL DISSIPATE BY THE END OF THE 48-HOUR
FORECAST PERIOD. THE GFS MODEL FORECAST FOR 500 MB SHOWS THAT
INVERTED TROUGHS WILL MOVE ACROSS HISPANIOLA FOR THE FIRST 24
HOURS OF THE 48-HOUR FORECAST PERIOD. SOUTHEASTERLY WIND FLOW
EVENTUALLY COVERS THE ENTIRE AREA FOR DAY TWO. THE GFS MODEL
FORECAST FOR 700 MB SHOWS THAT INVERTED TROUGHS WILL MOVE
WESTWARD ACROSS HISPANIOLA FOR THE NEXT 48 HOURS. EXPECT
VARIATIONS IN THE WIND DIRECTION.

THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N79W TO
30N79W. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS TO THE NORTH
AND NORTHWEST OF THE LINE THAT RUNS FROM 30N NORTHWARD IN
FLORIDA TO 30N80W BEYOND 32N78W. THE TROUGH SUPPORTS A COLD
FRONT THAT PASSES THROUGH 32N76W TO 31N80W. A STATIONARY FRONT
CONTINUES WESTWARD ALONG 30N/31N IN THE GULF COASTAL PLAINS OF
THE U.S.A. CONVECTIVE PRECIPITATION...ISOLATED MODERATE TO
LOCALLY STRONG FROM 29N NORTHWARD BETWEEN 64W AND 80W...AND
WITHIN A 30 NM RADIUS OF 27N79W.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM A 25N52W
CYCLONIC CIRCULATION CENTER...TO A 24N63W CYCLONIC CIRCULATION
CENTER. A SURFACE TROUGH IS ALONG 31N31W 26N39W 29N47W.
CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE FROM 24N
NORTHWARD BETWEEN 46W AND 66W.

AN UPPER LEVEL TROUGH EXTENDS FROM A 31N24W CYCLONIC CIRCULATION
CENTER...TO 25N26W. COMPARATIVELY DRIER AIR IN SUBSIDENCE
SURROUNDS THE CYCLONIC CENTER AND TROUGH.

A SURFACE RIDGE PASSES THROUGH 32N60W TO 29N66W...TO ANDROS
ISLAND IN THE BAHAMAS...THROUGH THE STRAITS OF FLORIDA...TO A
1016 MB HIGH PRESSURE CENTER THAT IS NEAR 24N90W...TO THE COAST
OF MEXICO ALONG 24N/25N.

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

$$
MT
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