[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201112
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU AUG 20 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
1045 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM DANNY AT 20/0900 UTC IS NEAR 12.2N
43.7W...OR 1040 NM TO THE EAST OF THE LESSER ANTILLES...MOVING
WESTWARD...OR 280 DEGREES...09 KNOTS. THE ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1000 MB. THE MAXIMUM SUSTAINED WIND SPEEDS
ARE 45 KNOTS WITH GUSTS TO 55 KNOTS. CONVECTIVE PRECIPITATION...
SCATTERED MODERATE TO ISOLATED STRONG WITHIN 60 NM OF THE CENTER
IN THE NORTHERN SEMICIRCLE...AND WITHIN A DISTANCE OF 150 NM OF
THE CENTER IN THE SOUTHWESTERN QUADRANT. PLEASE READ THE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24
KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 25W/26W FROM 22N
SOUTHWARD...MOVING WESTWARD 5 TO 10 KNOTS. THE WAVE IS JUST TO
THE WEST OF THE CAPE VERDE ISLANDS. CONVECTIVE PRECIPITATION...
WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 07N TO 15N
BETWEEN 23W AND 28W.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 20N62W TO 14N63W TO
08N64W IN VENEZUELA...MOVING WESTWARD 10 TO 15 KNOTS. CONVECTIVE
PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG WITHIN A
DISTANCE OF 180 NM FROM THE COAST OF SOUTH AMERICA BETWEEN 54W
NEAR THE COAST OF SURINAME AND 65W ALONG THE COAST OF VENEZUELA
IN THE SOUTHEASTERN CORNER OF THE CARIBBEAN SEA...INCLUDING
ACROSS TRINIDAD.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF SENEGAL
NEAR 14N17W TO 12N29W AND 13N36W. NO ITCZ IS PRESENT AT THIS
TIME. CONVECTIVE PRECIPITATION...WIDELY SCATTERED TO SCATTERED
MODERATE AND ISOLATED STRONG FROM 08N TO 17N BETWEEN 14W AND
20W. SCATTERED MODERATE TO ISOLATED STRONG WITHIN A DISTANCE OF
180 NM FROM THE COAST OF SOUTH AMERICA BETWEEN 54W NEAR THE
COAST OF SURINAME AND 65W ALONG THE COAST OF VENEZUELA IN THE
SOUTHEASTERN CORNER OF THE CARIBBEAN SEA...INCLUDING ACROSS
TRINIDAD. ISOLATED MODERATE ELSEWHERE FROM 07N TO 13N BETWEEN
30W AND 40W...FROM 03N TO 10N BETWEEN 40W AND 50W...AND FROM 10N
SOUTHWARD BETWEEN 50W AND 60W.

...DISCUSSION...

THE GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS ALONG 99W/100W IN
MEXICO. THE CYCLONIC WIND FLOW THAT IS MOVING AROUND THE TROUGH
COVERS MEXICO AND SOUTH TEXAS. A COLD FRONT ALSO CUTS ACROSS
TEXAS...FROM NORTHEASTERN LOUISIANA INTO CENTRAL TEXAS...TO THE
TEXAS BIG BEND. THE COLD FRONT IS BEING DRIVEN BY A SEPARATE
DEEP LAYER TROUGH THAT IS MOVING THROUGH THE CENTRAL U.S.A.

RESULTING UPPER LEVEL ANTICYCLONIC WIND FLOW WITH A RIDGE COVERS
THE OPEN WATERS OF THE GULF OF MEXICO...ALONG A NORTHEAST-TO-
SOUTHWEST ORIENTATION. A COMPARATIVELY WEAK SURFACE PRESSURE
GRADIENT EXISTS IN THE GULF OF MEXICO. A SURFACE RIDGE ENTERS
THE AREA FROM THE NORTHERN BAHAMAS...SOUTHWESTWARD INTO THE
SOUTHWESTERN CORNER OF THE AREA. CONVECTIVE PRECIPITATION...
NUMEROUS STRONG IN THE COASTAL WATERS AND COASTAL PLAINS OF THE
UPPER TEXAS GULF COAST AND SOUTHERN LOUISIANA. SCATTERED
MODERATE TO ISOLATED STRONG COVERS THE DEEP SOUTH OF TEXAS.

THE CARIBBEAN SEA...

MIDDLE LEVEL TO UPPER LEVEL CYCLONIC WIND FLOW COVERS THE
CARIBBEAN SEA FROM 74W WESTWARD. THE CYCLONIC CIRCULATION CENTER
IS NEAR 17N85W. CONVECTIVE PRECIPITATION...BROKEN MULTILAYERED
CLOUDS ARE BETWEEN 76W AND 86W. ISOLATED MODERATE TO LOCALLY
STRONG FROM 17N SOUTHWARD BETWEEN 80W AND 85W...REACHING THE
COAST OF NICARAGUA.

THE REST OF THE CARIBBEAN SEA CONSISTS OF A MIXTURE OF UPPER
LEVEL WESTERLY WIND FLOW WITH UPPER LEVEL SOUTHEASTERLY WIND
FLOW BETWEEN 66W AND 73W. MIDDLE LEVEL EASTERLY WIND FLOW COVERS
THE AREA THAT IS FROM 64W EASTWARD.

MAINLY MODERATE TO LOCALLY FRESH TRADE WINDS WILL PREVAIL ACROSS
THE AREA THROUGH THE NEXT 48 HOURS...EXCEPT NEAR THE COAST OF
COLOMBIA AND IN THE GULF OF VENEZUELA WHERE STRONG TO NEAR GALE
FORCE WINDS WILL PERSIST...AND IN THE GULF OF HONDURAS WHERE
WINDS WILL PULSE TO FRESH TO STRONG DURING THE OVERNIGHT HOURS.
THE SEA HEIGHTS WILL RANGE FROM 3 TO 6 FEET...EXCEPT UP TO 13
FEET NEAR THE COAST OF COLOMBIA AND UP TO 7 FEET IN THE GULF OF
HONDURAS.

...HISPANIOLA...

OBSERVATIONS...IN HAITI...FEW LOW LEVEL CLOUDS FOR PORT-AU-
PRINCE IN HAITI. FOR THE DOMINICAN REPUBLIC...FEW LOW LEVEL
CLOUDS ARE IN BARAHONA...SANTO DOMINGO...AND IN LA ROMANA.
SCATTERED LOW LEVEL CLOUDS ARE IN PUNTA CANA. FEW LOW LEVEL
CLOUDS ARE IN SANTIAGO. FEW LOW LEVEL CLOUDS AND SCATTERED HIGH
LEVEL CLOUDS ARE BEING REPORTED IN PUERTO PLATA.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT A RIDGE WILL CUT
ACROSS HISPANIOLA FOR THE FIRST 24 HOURS. A TROUGH WILL CUT
ACROSS THE CARIBBEAN SEA FROM THE NORTHEASTERN PART OF THE
U.S.A...AND IT WILL PASS DIRECTLY ON TOP OF HISPANIOLA. THE 500
MB FORECAST SHOWS THAT A RIDGE WILL CUT ACROSS THE AREA. THE 700
MB FORECAST SHOWS THAT MULTIPLE INVERTED TROUGHS WILL MOVE
ACROSS THE AREA.

THE ATLANTIC OCEAN...

TROPICAL STORM DANNY IS IN THE ATLANTIC OCEAN. PLEASE READ THE
SPECIAL FEATURES SECTION FOR MORE DETAILS ABOUT THE TROPICAL
STORM.

A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
NEAR 34N64W. CYCLONIC WIND FLOW COVERS THE AREA FROM 26N
NORTHWARD BETWEEN 55W AND THE U.S.A. EAST COAST. MIDDLE LEVEL TO
UPPER LEVEL CYCLONIC WIND FLOW ALSO COVERS THE ATLANTIC OCEAN
FROM 27N NORTHWARD BETWEEN 35W AND 55W...THANKS TO TWO
INDIVIDUAL CYCLONIC CIRCULATION CENTERS ONE NEAR 34N42W AND THE
OTHER ONE NEAR 32N52W...THAT ARE ALONG AND JUST TO THE NORTH OF
32N IN THAT AREA. CONVECTIVE PRECIPITATION...SCATTERED MODERATE
TO ISOLATED STRONG FROM 26N NORTHWARD BETWEEN 58W AND 70W.
ISOLATED MODERATE FROM 25N NORTHWARD BETWEEN 38W AND 58W...AND
FROM 28N NORTHWARD BETWEEN 70W AND THE U.S.A. COAST.

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

$$
MT
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