Tropical Weather Discussion
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000
AXNT20 KNHC 042342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI SEP 04 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
2330 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION FRED IS CENTERED NEAR 22.6N 39.1W AT 04/2100
UTC OR ABOUT 1112 NM SW OF THE AZORES...MOVING WNW AT 8 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED
WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. A CLUSTER OF MODERATE
CONVECTION PREVAILS FROM 21N-24N BETWEEN 36W-39W. PLEASE SEE THE
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

A TROPICAL WAVE IS BETWEEN THE AFRICAN COAST AND THE CAPE VERDE
ISLANDS WITH AN AXIS EXTENDING FROM 18N21W INTO A 1009 MB
SURFACE LOW CENTERED NEAR 11N21W. SCATTERED MODERATE CONVECTION
IS FROM 09N-13N BETWEEN 19W-25W. THIS SYSTEM SHOWS SIGNS OF
ORGANIZATION AND HAS A HIGH CHANCE OF DEVELOPING INTO A TROPICAL
CYCLONE OVER THE NEXT 48 HOURS AS IT MOVES W AT 15 TO 20 KT.

...TROPICAL WAVES...

A TROPICAL WAVE IS BETWEEN THE AFRICAN COAST AND CAPE VERDE
ISLANDS AND IT IS CONNECTED TO A SURFACE LOW PREVIOUSLY
DISCUSSED IN THE SPECIAL FEATURES SECTION. PLEASE REFER TO THE
SECTION ABOVE FOR DETAILS.

A TROPICAL WAVE IS OVER THE EASTERN ATLANTIC WITH AXIS THAT
EXTENDS FROM 19N28W INTO A 1008 MB LOW NEAR 12N29W...MOVING W AT
AROUND 15 KT OVER THE PAST 24 HOURS. SSMI TPW SHOWS THE WAVE IS
EMBEDDED IN HIGH MOISTURE MAINLY S OF 15N. ISOLATED CONVECTION
MODERATE CONVECTION IS FROM 11N-13N BETWEEN 29W-31W.

A TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AN AXIS
EXTENDING FROM 16N53W TO 09N56W...MOVING W AT 15 TO 20 KT OVER
THE PAST 24 HOURS. TPW IMAGERY SHOWS THIS WAVE IN A DRY
ENVIRONMENT THEREFORE...NO SIGNIFICANT CONVECTION IS NOTED AT
THIS TIME.

A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN WITH AXIS
EXTENDING FROM 19N65W TO 11N65W...MOVING W AT AROUND 15 KT. THIS
WAVE IS DEPICTED BY 700 MB MODEL FIELDS WITH A TROUGH BETWEEN
60W AND 68W. TPW IMAGERY DEPICTS MODERATE MOISTURE SURROUNDING
THIS WAVE BUT AT THIS MOMENT NO SIGNIFICANT CONVECTION IS NOTED.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM OVER AFRICA INTO THE E
TROPICAL ATLANTIC NEAR 14N17W...THROUGH THE 1009 MB LOW/TROPICAL
WAVE NEAR 11N21W...THROUGH THE 1008 MB LOW/TROPICAL WAVE NEAR
12N29W...TO 12N38W...WHERE THE ITCZ BEGINS AND CONTINUES TO
09N60W. ASIDE FROM THE CONVECTION ASSOCIATED WITH THE TWO
LOWS...NO SIGNIFICANT CONVECTION IS OBSERVED AT THIS TIME.

...DISCUSSION...

GULF OF MEXICO...

A 1017 MB SURFACE HIGH IS OVER THE NE GULF NEAR 27N87W AND
EXTENDING ACROSS THE BASIN. WITH THIS...A LIGHT TO GENTLE
ANTICYCLONIC FLOW PREVAILS ACROSS THE AREA AS NOTED IN
SCATTEROMETER DATA. UPPER-LEVEL DIFFLUENCE SUPPORTS ISOLATED
MODERATE CONVECTION ACROSS THE EASTERN HALF OF THE BASIN MAINLY
E OF 90W. TO THE SW...A DIURNAL SURFACE TROUGH EXTENDS FROM
23N96W TO 20N97W. OVER THE NEXT 24 HOURS...EXPECT FOR CONVECTION
TO CONTINUE ACROSS THE EASTERN GULF SUPPORTED BY THE PERSISTENT
UPPER-LEVEL DIFFLUENCE.

CARIBBEAN SEA...

AN UPPER-LEVEL LOW IS CENTERED ACROSS THE W CARIBBEAN NEAR
16N88W. UPPER-LEVEL DIFFLUENCE PREVAILS BETWEEN 78W-84W
SUPPORTING SCATTERED MODERATE TO STRONG CONVECTION ACROSS
CENTRAL AMERICA AND THE S CARIBBEAN WATERS MAINLY S OF 17N. TO
THE E...ANOTHER UPPER-LEVEL LOW IS CENTERED OVER THE MONA
PASSAGE NEAR 19N67W. DRY AIR AND STRONG SHEAR OVER THE EASTERN
CARIBBEAN IS INHIBITING ANY SIGNIFICANT CONVECTION ASSOCIATED
WITH THIS UPPER LOW. A TROPICAL WAVE IS OVER THE E CARIBBEAN.
PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS.
OVER THE NEXT 24 HOURS...CONVECTION IS EXPECTED TO CONTINUE OVER
THE W CARIBBEAN.

...HISPANIOLA...

SHALLOW MOISTURE AND DAYTIME HEATING SUPPORTS ISOLATED SHOWERS
AND THUNDERSTORMS OVER THE ISLAND THIS EVENING. THIS ACTIVITY
WILL DISSIPATE OVERNIGHT. A SIMILAR PATTERN IS FORECAST TO
CONTINUE OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...

A 1012 MB SURFACE LOW NEAR 29N76W WITH A SURFACE TROUGH
EXTENDING FROM THE LOW REACHING THE FLORIDA PENINSULA NEAR
28N83W. SCATTERED MODERATE TO STRONG CONVECTION PREVAILS ACROSS
THE FLORIDA PENINSULA AND EXTENDING E ACROSS THE W ATLANTIC
MAINLY W OF 78W. TO THE E...A 1010 MB SURFACE LOW N OF OUR AREA
EXTENDS ITS SURFACE TROUGH FROM 31N63W TO 27N65W. SCATTERED
MODERATE CONVECTION IS OBSERVED MAINLY N OF 26N BETWEEN 54W-64W.
A WEAK 1015 MB SURFACE LOW IS CENTERED NEAR 31N49W WITH SURFACE
TROUGH EXTENDING FROM THE LOW TO 26N52W. A CLUSTER OF MODERATE
CONVECTION IS FROM 28N-32N BETWEEN 43W-47W. THE REMAINDER OF THE
AREA IS UNDER THE INFLUENCE OF A 1020 MB SURFACE HIGH CENTERED
NEAR 30N25W. TROPICAL DEPRESSION FRED AND A SPECIAL FEATURE LOW
WITH ITS ASSOCIATED TROPICAL WAVE ARE OVER THE CENTRAL AND
EASTERN ATLANTIC...RESPECTIVELY. PLEASE REFER TO THE SPECIAL
FEATURES SECTION FOR MORE DETAILS. TWO OTHER TROPICAL WAVES ARE
OVER THE TROPICAL ATLANTIC. PLEASE REFER TO THE TROPICAL WAVES
SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS...EXPECT
CONVECTION TO BE LIKELY N OF 25N W OF 55W WITH THE TWO WESTERN
ATLANTIC SURFACE TROUGHS AND THE W ATLANTIC SURFACE LOW.

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

$$

ERA



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