[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT AUG 22 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...
HURRICANE DANNY IS CENTERED NEAR 14.8N 49.8W AT 22/0300 UTC OR
ABOUT 700 NM E OF THE LEEWARD ISLANDS MOVING WNW AT 9 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 977 MB. MAXIMUM SUSTAINED
WIND SPEED IS 95 KT WITH GUSTS TO 115 KT. SCATTERED MODERATE
CONVECTION IS OCCURRING WITHIN 90 NM OF THE CENTER. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24
KNHC FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 08N20W TO 18N21W MOVING W AT 10 KT.
THE WAVE COINCIDES WITH A RELATIVELY BROAD LOW-LEVEL MONSOONAL
GYRE CENTERED ALONG THE MONSOON TROUGH NEAR 13N22W. THE GYRE AND
ASSOCIATED WAVE ENERGY IS EXPECTED TO DRIFT WESTWARD THROUGH
SUNDAY. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 13N-16N
BETWEEN 20W-26W...WITH ISOLATED MODERATE CONVECTION ELSEWHERE
FROM 05N-16N BETWEEN 13W-29W.

TROPICAL WAVE EXTENDS FROM 08N34W TO 20N34W MOVING W AT 10-15
KT. THIS WAVE IS EMBEDDED WITHIN SAHARAN DUST AND DRY AIR
RESULTING IN MOSTLY STABLE CONDITIONS. THE OVERALL STABILITY
SURROUNDING THE WAVE AXIS IS INHIBITING AND SIGNIFICANT DEEP
CONVECTION AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 11N77W TO 19N78W MOVING W AT 15-20
KT. THE WAVE IS ENCOUNTERING DRY AND STABLE AIR ALOFT WITH NO
SIGNIFICANT DEEP CONVECTION NOTED ON SATELLITE IMAGERY AT THIS
TIME.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
16N17W TO 08N33W TO 09N43W. ASIDE FROM CONVECTION ASSOCIATED
WITH THE TROPICAL WAVE ALONG 21W...ISOLATED MODERATE CONVECTION
IS FROM 05N-08N BETWEEN 37W-44W.

...DISCUSSION...

GULF OF MEXICO...
GENERALLY EASTERLY FLOW ALOFT INFLUENCES MUCH OF THE GULF BASIN
BETWEEN AN UPPER LEVEL RIDGE ANCHORED OVER NORTHERN FLORIDA AND
THE NE GULF NEAR 30N82W AND AN UPPER LEVEL LOW CENTERED OVER THE
SW GULF NEAR 20N91W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING
AROUND THE PERIPHERY OF BOTH UPPER LEVEL FEATURES WITH NO
SIGNIFICANTLY ORGANIZED CONVECTION. LIGHT AND VARIABLE
ANTICYCLONIC WINDS AND 1-3 FT SEAS WILL PERSIST ACROSS THE NE
HALF OF THE GULF...WITH MODERATE TO LOCALLY FRESH SE RETURN FLOW
AND 3-6 FT SEAS ACROSS THE SW HALF OF THE GULF. THE STRONGEST
WINDS ARE EXPECTED NW OF THE YUCATAN PENINSULA DURING THE
EVENING AND OVERNIGHT HOURS AS DIURNAL TROUGHING DEVELOPS OVER
THE PENINSULA EACH AFTERNOON. THE TROUGHING WILL THEN MOVE TO
THE WESTERN OFFSHORE WATERS AND INTO THE SW GULF WHERE IT WILL
DISSIPATE BY SUNRISE EACH DAY. THESE CONDITIONS ARE FORECAST TO
PERSIST THROUGH THE NEXT 48 HOURS.

CARIBBEAN SEA...
AN UPPER LEVEL CYCLONE IS CENTERED OVER THE SW GULF OF MEXICO
NEAR 20N91W WHILE AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER
THE SW CARIBBEAN NEAR 12N81W. W OF 74W...ONLY ISOLATED SHOWERS
AND TSTMS ARE OCCURRING AROUND THE PERIPHERY OF BOTH OF THESE
FEATURES WITH THE MOST ACTIVE AREA NOTED S OF 13N W OF
79W...INCLUDING INLAND PORTIONS OF PANAMA...COSTA RICA...AND SE
NICARAGUA. E OF 74W...AN UPPER LEVEL TROUGH AXIS EXTENDS FROM
19N59W TO 17N73W AND REMAINS EMBEDDED WITHIN VERY DRY AND STABLE
AIR ALOFT. MAINLY MODERATE TO LOCALLY FRESH TRADES AND 3-6 FT
SEAS WILL PREVAIL ACROSS THE BASIN THROUGH THE WEEKEND...EXCEPT
IN THE S CENTRAL CARIBBEAN WHERE THE PRESSURE GRADIENT WILL BE
STRONG ENOUGH TO SUPPORT OCCASIONAL WINDS TO 20-25 KT WHICH WILL
BUILD SEAS TO 7-9 FT.

...HISPANIOLA...
SHALLOW LOW TO MID-LEVEL MOISTURE LINGERS ACROSS HISPANIOLA THIS
EVENING WITH ONLY A FEW ISOLATED SHOWERS CONTINUING TO DIMINISH.
OTHERWISE...SIMILAR DEVELOPMENT OF LATE AFTERNOON AND EARLY
EVENING ISOLATED SHOWERS AND TSTMS IS POSSIBLE THROUGH THE
WEEKEND WITH LITTLE CHANGE IN OVERALL SYNOPTIC CONDITIONS
ANTICIPATED.

ATLANTIC OCEAN...
AN UPPER LEVEL ANTICYCLONE IS CENTERED EAST OF NORTHERN FLORIDA
NEAR 30N79W. AN UPPER LEVEL CYCLONE IS JUST N OF THE DISCUSSION
AREA NEAR 33N66W WITH A TRAILING UPPER LEVEL TROUGH EXTENDING S
TO 25N65W. THE UPPER LEVEL CYCLONE AND TROUGH ARE SUPPORTING A
1013 MB LOW NEAR 30N63W WITH A SURFACE TROUGH EXTENDING FROM
32N64W INTO THE LOW THEN TO 25N66W TO 26N75W. SCATTERED SHOWERS
AND TSTMS ARE OCCURRING N OF 24N BETWEEN 56W-67W TO THE EAST OF
THE BOUNDARY. THE LOW IS FORECAST TO MOVE TO THE NW REACHING
35N67W IN 24 HOURS. LIGHT AND VARIABLE WINDS WILL PERSIST ACROSS
THE ENTIRE SW NORTH ATLC OFFSHORE WATERS BASIN THROUGH THE NEXT
48 HOURS. SEAS OF 3 FT OR LESS ARE EXPECTED W OF 70W...WITH 3-5
FT SEAS E OF 70W. ANOTHER UPPER LEVEL LOW IS CENTERED NEAR
32N49W THAT SUPPORTS A SURFACE TROUGH FROM 31N45W TO 28N47W TO
27N51W. ISOLATED SHOWERS ARE OCCURRING FROM 30N-36N BETWEEN 43W-
49W.

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

$$
HUFFMAN
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