[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED SEP 16 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...
TROPICAL DEPRESSION NINE IS CENTERED NEAR 15.2N 44.6W AT 16/2100
UTC OR ABOUT 965 NM E OF THE LESSER ANTILLES AND ABOUT 1190 NM W
OF THE CAPE VERDE ISLANDS MOVING NW AT 7 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1009 MB. MAXIMUM SUSTAINED WIND SPEED IS 25
KT WITH GUSTS TO 35 KT. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 14N-16N BETWEEN 41W-44W. WIDELY SCATTERED
MODERATE CONVECTION IS ELSEWHERE FROM 13N-22N BETWEEN 37W-44W.
SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

TROPICAL WAVE EXTENDS FROM A 1010 MB LOW CENTERED ALONG THE
MONSOON TROUGH NEAR 11N29W TO 17N29W MOVING WNW AT 10-15 KT.
ONGOING CONVECTION LARGELY REMAINS DISORGANIZED...WITH ISOLATED
MODERATE OCCURRING FROM 06N-13N BETWEEN 27W-36W. THERE IS A HIGH
CHANCE OF TROPICAL FORMATION OVER THE NEXT 48 HOURS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 11N72W TO 20N70W MOVING W AT 10-15
KT. THE WAVE COINCIDES WITH FAIRLY BROAD AND WEAK 700 MB
TROUGHING OVER THE CENTRAL CARIBBEAN SEA AND CONTINUES TO
INTERACT WITH AN UPPER LEVEL TROUGH WITH AXIS EXTENDING NW OF
THE WAVE AXIS FROM 24N70W TO 17N76W. SCATTERED MODERATE
CONVECTION IS FROM 16N-21N BETWEEN 68W-73W.

TROPICAL WAVE EXTENDS FROM 14N90W TO 21N89W W AT 10-15 KT. A
LARGE PORTION OF THE WAVE'S FRACTURED ENERGY CONTINUES TO BE
LOCATED TO THE NORTH ACROSS THE EASTERN GULF OF MEXICO...HOWEVER
RESIDUAL ENERGY CONTINUES WESTWARD OVER GUATEMALA AND THE
YUCATAN PENINSULA WITH ISOLATED MODERATE CONVECTION FROM 14N-19N
BETWEEN 89W-93W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 18N16W TO
THE 1010 MB SPECIAL FEATURES LOW NEAR 11N29W TO 11N35W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N50W TO
09N61W. ASIDE FROM CONVECTION OCCURRING WITH THE SPECIAL
FEATURES LOW AND TROPICAL DEPRESSION NINE...ISOLATED MODERATE
CONVECTION IS FROM 06N-12N BETWEEN 13W-20W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL TROUGH
OVER THE SE CONUS AND EASTERN GULF OF MEXICO WITH AXIS EXTENDING
FROM EAST-CENTRAL ALABAMA S-SW TO A BASE NEAR 25N88W. THE
TROUGHING ALOFT REFLECTS AS A SURFACE TROUGH EXTENDING FROM
29N86W TO 23N88W WITH SCATTERED SHOWERS AND TSTMS OCCURRING
ACROSS A LARGE PORTION OF THE EASTERN GULF...FLORIDA
PENINSULA...AND FLORIDA STRAITS. THE UPPER LEVEL TROUGHING IS
FORECAST TO VERY SLOWLY SLIDE EASTWARD THROUGH THE UPCOMING
WEEKEND AND LIKELY CONTINUE TO GENERATE PRECIPITATION AND
CONVECTION FOR THE EASTERN GULF AND FLORIDA PENINSULA.
OTHERWISE...THE WESTERN GULF IS UNDER THE INFLUENCE OF DRY AND
STABLE NORTHERLY FLOW ALOFT AND A SURFACE RIDGE EXTENDING FROM
THE LOWER MISSISSIPPI RIVER VALLEY TO NE MEXICO. GENERALLY
GENTLE TO MODERATE E-NE WINDS ARE EXPECTED EAST OF THE INFLUENCE
OF THE SURFACE TROUGH AND ONGOING CONVECTION THROUGH THE
OVERNIGHT HOURS.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE AXIS EXTENDS FROM OVER THE YUCATAN
PENINSULA E-NE OVER CUBA AND INTO THE SW NORTH ATLC BEYOND
26N79W. THE RIDGING ALOFT CONTINUES TO SUPPORT ISOLATED SHOWERS
AND TSTMS N OF 20N W OF 79W IN AREAS OF MAXIMIZED DIFFLUENCE
THIS EVENING. FARTHER EAST...AN UPPER LEVEL TROUGH IS NOTED ON
WATER VAPOR IMAGERY OVER THE WINDWARD PASSAGE REGION. DIFFLUENCE
ON THE EASTERN PERIPHERY OF THE TROUGHING AND THE PRESENCE OF A
TROPICAL WAVE ALONG 71W IS GENERATING SCATTERED SHOWERS AND
TSTMS ACROSS HISPANIOLA AND THE ADJACENT COASTAL WATERS N OF 16N
BETWEEN 67W-73W. OTHERWISE...MODERATE TO FRESH TRADES PREVAIL
AND GENERALLY ARE EXPECTED TO PERSIST THROUGH THE UPCOMING
WEEKEND.

...HISPANIOLA...
PRESENTLY SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS
HISPANIOLA THIS EVENING DUE TO THE PRESENCE OF A TROPICAL WAVE.
AS THE WAVE IS FORECAST TO CONTINUE MOVING WESTWARD DURING THE
NEXT 24 HOURS...CONDITIONS ARE EXPECTED TO GRADUALLY IMPROVE
THROUGH THURSDAY INTO FRIDAY.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS OVER THE SE CONUS AND EXTENDS OVER
PORTIONS OF THE EASTERN GULF OF MEXICO. TO THE EAST OF THE
TROUGHING...MIDDLE TO UPPER LEVEL DIFFLUENCE IS MAXIMIZED
GENERATING SCATTERED SHOWERS AND TSTMS N OF 23N W OF 74W. TO THE
SE...ANOTHER UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY
CENTERED OVER THE WINDWARD PASSAGE REGION. WHILE A TROPICAL WAVE
IS ACROSS THE CENTRAL CARIBBEAN SEA...MIDDLE TO UPPER LEVEL
DIFFLUENCE EAST OF THE TROUGH AXIS ALONG WITH POTENTIAL ENERGY
FRACTURED NE FROM THE TROPICAL WAVE IS GENERATING SCATTERED
SHOWERS AND ISOLATED TSTMS FROM 20N-24N BETWEEN 60W-70W. ACROSS
THE CENTRAL ATLC...A SURFACE TROUGH IS ANALYZED FROM 23N51W TO
29N48W IN RESPONSE TO A SHORTWAVE TROUGH NOTED ON WATER VAPOR
IMAGERY IN THE VICINITY OF 26N50W. ISOLATED SHOWERS AND TSTMS
ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE BOUNDARY.
FINALLY...MOSTLY TRANQUIL CONDITIONS ARE NOTED ACROSS THE
EASTERN ATLC FOCUSED AROUND A 1019 MB HIGH CENTERED NEAR 31N35W
THAT IS EXPECTED TO SLIDE SOUTHEASTWARD DURING THE NEXT 24
HOURS.

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

$$
HUFFMAN
This weather bulletin was brought to you by:
www.nashvilleweather.net