[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211750
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI AUG 21 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

THE CENTER OF HURRICANE DANNY AT 21/1500 UTC WAS NEAR 14.0N
48.2W...OR 810 NM TO THE EAST OF THE WINDWARD ISLANDS...MOVING
WEST-NORTHWESTWARD...OR 290 DEGREES...AT 09 KNOTS. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 976 MB. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 90 KNOTS WITH GUSTS TO 110 KNOTS. CLUSTERS OF
MODERATE TO STRONG CONVECTION ARE WITHIN 80 NM OF THE CENTER OF
DANNY. SCATTERED MODERATE CONVECTION IS ELSEWHERE WITHIN 150 NM
OF THE CENTER. PUBLIC ADVISORIES ABOUT HURRICANE DANNY ARE BEING
ISSUED UNDER WMO HEADER WTNT34 KNHC AND UNDER AWIPS HEADER
MIATCPAT4. FORECAST/ADVISORIES ABOUT HURRICANE DANNY ARE BEING
ISSUED UNDER WMO HEADER WTNT24 KNHC AND UNDER AWIPS HEADER
MIATCMAT4.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE EASTERN ATLC WITH AN AXIS EXTENDING
FROM 20N33W TO 06N33W...MOVING W AT 10 TO 15 KT OVER THE PAST 24
HOURS. THIS WAVE IS EMBEDDED IN DRY AIR...TO THE WEST OF A SURGE
OF MOISTURE OFF OF THE COAST OF AFRICA ASSOCIATED WITH ANOTHER
TROPICAL WAVE. AN INVERTED 700 MB TROUGH IS NOTED BETWEEN 30W
AND 36W. NO DEEP CONVECTION IS OCCURRING WITH THIS WAVE.

A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN WITH AN AXIS
EXTENDING FROM 19N72W TO 11N73W...MOVING W AT 15 TO 20 KT OVER
THE PAST 24 HOURS. THIS WAVE IS CURRENTLY EMBEDDED IN DRY AIR. A
SUBTLE 700 MB TROUGH IS NOTED BETWEEN 71W AND 80W. NO DEEP
CONVECTION IS NOTED WITH THIS WAVE.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF AFRICA
NEAR 16N17W TO 10N25W TO 08N38W. NO ITCZ IS NOTED AT THIS TIME
DUE TO THE PRESENCE OF HURRICANE DANNY OVER THE TROPICAL CENTRAL
ATLC. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM
06N TO 16N BETWEEN 15W AND 30W.

...DISCUSSION...

GULF OF MEXICO...

AN UPPER LEVEL ANTICYCLONE IS OVER THE NE GULF WHILE AN UPPER LOW
IS OVER THE YUCATAN PENINSULA...THE RESULT IS AN AREA OF UPPER
LEVEL DIFFLUENCE OVER WESTERN GULF THAT SUPPORTS A SCATTERED
MODERATE CONVECTION FROM 28N TO 31N BETWEEN 91W AND 97W.
ELSEWHERE...DEEP LOW TO MID LEVEL MOISTURE ACROSS MUCH OF THE
BASIN IS RESULTING IN ISOLATED TO SCATTERED THUNDERSTORM
ACTIVITY ACROSS THE MAJORITY OF THE BASIN...WITH THE GREATEST
COVERAGE OVER THE NE GULF...AND LEAST COVERAGE OVER THE SW GULF.
WEAK ANTICYCLONIC WINDS MAINLY FROM 5 TO 15 KT COVER THE GULF
AROUND A SURFACE RIDGE AXIS EXTENDING FROM CENTRAL FL TO THE
CENTRAL GULF. OVER THE NEXT 24 HOURS THE UPPER LEVEL ANTICYCLONE
IS FORECAST TO EXPAND ACROSS MUCH OF THE REMAINDER OF THE
GULF...WITH DEEP CONVECTION CONFINED TO THE SW GULF...AND
ISOLATED THUNDERSTORMS ELSEWHERE.

CARIBBEAN SEA...

AN UPPER LOW IS OVER THE YUCATAN PENINSULA...WHILE AN UPPER
LEVEL ANTICYCLONE IS CENTERED OVER THE SW CARIBBEAN NEAR 12N80W.
AN ELONGATED UPPER LEVEL TROUGH EXTENDS FROM THE CENTRAL ATLC SE
TO THE EASTERN CARIBBEAN. THE UPPER LEVEL DIFFLUENCE ASSOCIATED
WITH THE ANTICYCLONE AND THE NEARBY E PACIFIC MONSOON TROUGH
SUPPORTS SCATTERED MODERATE CONVECTION S OF 11N W OF 78W. A
TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN. PLEASE REFER TO THE
TROPICAL WAVES SECTION FOR MORE DETAILS. DRY AIR IS INHIBITING
CONVECTION ACROSS THE MAJORITY OF THE REMAINDER OF THE CARIBBEAN
TODAY. MODERATE TO FRESH TRADE WINDS ARE OVER THE S CENTRAL
CARIBBEAN. GENTLE TO MODERATE TRADE WINDS ARE ELSEWHERE OVER THE
CARIBBEAN WITH THE WEAKEST WINDS OVER THE NW CARIBBEAN. EXPECT
CONVECTION TO CONTINUE OVER THE SW CARIBBEAN OVER THE NEXT 24
HOURS.

...HISPANIOLA...

SHALLOW LOW TO MID LEVEL MOISTURE WILL SUPPORT ISOLATED
THUNDERSTORMS THIS AFTERNOON AND EVENING. GENERALLY FAIR WEATHER
IS EXPECTED OVERNIGHT TONIGHT. ADDITIONAL ISOLATED THUNDERSTORM
DEVELOPMENT WILL BE POSSIBLE ON SATURDAY AFTERNOON.

ATLANTIC OCEAN...

AN UPPER TROUGH CENTERED N OF OUR AREA OF DISCUSSION OVER THE W
ATLC SUPPORTS A 1012 MB LOW NEAR 29N64W. SURFACE TROUGHING
EXTENDS FROM THIS LOW TO 25N70 AND ALSO TO 29N60W. SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION ARE WITHIN 75 NM OF A
LINE FROM 25N70W TO 27N63W...AND FROM 26N TO 31N BETWEEN 55W AND
63W. AN UPPER LOW N OF OUR AREA OF DISCUSSION OVER THE CENTRAL
ATLC SUPPORTS A 1012 MB SURFACE LOW NEAR 29N44W WITH A SURFACE
TROUGH EXTENDING FROM THE LOW CENTER TO 26N48W. SCATTERED
MODERATE CONVECTION IS N OF 30N BETWEEN 39W AND 43W. HURRICANE
DANNY IS OVER THE CENTRAL TROPICAL ATLC. PLEASE SEE THE SPECIAL
FEATURES SECTION FOR MORE DETAILS. A TROPICAL WAVE IS OVER THE
EASTERN ATLC. PLEASE SEE THE TROPICAL WAVES SECTION FOR MORE
DETAILS. OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE N OF
25N NEAR 60W ASSOCIATED WITH THE W ATLC SURFACE LOW.

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

$$
LATTO
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