Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 032348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU SEP 03 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
2345 UTC.

...SPECIAL FEATURES...

TROPICAL STORM FRED CENTERED NEAR 22.0N 35.4W AT 03/2100 UTC OR
AT ABOUT 740 NM WNW OF THE CAPE VERDE ISLANDS MOVING WNW AT 10
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM
SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SCATTERED
MODERATE CONVECTION IS FROM 21N-24N BETWEEN 32W-36W. FRED IS
FORECAST TO WEAKEN TO A TROPICAL DEPRESSION TONIGHT...THEN
BECOME A POST-TROPICAL REMNANT LOW BY EARLY FRIDAY. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21
KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER WESTERN AFRICA WIT AXIS EXTENDING FROM
16N14W TO 08N14W...MOVING W AROUND 10 KT. THE WAVE COINCIDES
WITH 700 MB TROUGHING BETWEEN 10W-18W AND IS LARGELY LOW-
AMPLITUDE. ABUNDANT MOISTURE SURROUNDS THIS WAVE AND A LOW LEVEL
CIRCULATION IS TRYING TO DEVELOP. SCATTERED MODERATE CONVECTION
IS FROM 07N-15N BETWEEN 14W-20W.

A TROPICAL WAVE IS OVER THE E ATLANTIC WITH AXIS EXTENDING FROM
20N26W THROUGH A 1012 MB LOW NEAR 13N26W TO 11N26W. THE WAVE IS
MOVING W AT 10-15 KT. A 700 MB TROUGHING IS DEPICTED BY GLOBAL
MODELS BETWEEN 23W-30W AND SSMI TPW INDICATES THE WAVE IS
EMBEDDED WITHIN A SURGE OF DEEP MOISTURE. SCATTERED MODERATE
CONVECTION IS OBSERVED AROUND THE LOW FROM 10N-13N BETWEEN
25W-30W.

A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL ATLANTIC WITH AXIS
EXTENDING FROM 16N48W TO 08N45W...MOVING W AT 5-10 KT. THE WAVE
COINCIDES WITH A BROAD 700 MB TROUGHING BETWEEN 47W-51W. SSMI
TPW INDICATES THE WAVE IS EMBEDDED WITHIN A SURGE OF LIGHT TO
MODERATE MOISTURE WHICH IS BEING HINDERED BY SURROUNDING SAHARAN
DRY AIR AND DUST. WITH THIS...NO SIGNIFICANT CONVECTION IS
PRESENT ALONG THIS WAVE.

A TROPICAL WAVE IS APPROACHING CENTRAL AMERICA...WITH AXIS
EXTENDING FROM 17N82W TO 10N83W...MOVING W AT 10-15 KT. THE WAVE
COINCIDES WITH A BROAD 700 MB TROUGHING BETWEEN 80W-84W. SSMI
TPW INDICATES THE WAVE IS EMBEDDED WITHIN A SURGE OF MOISTURE.
THIS AREA IS ALSO INFLUENCED BY AN UPPER-LEVEL LOW WHICH
COMBINED WITH THE WAVE IS SUPPORTING MAINLY S OF 15N AND W OF
78W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
14N17W TO 11N30W TO 09N45W. THE INTERTROPICAL CONVERGENCE ZONE
AXIS EXTENDS W OF A TROPICAL WAVE FROM 09N47W TO 06N53W. ASIDE
FROM THE CONVECTION RELATED TO THE TROPICAL WAVE AND LOW
PRESSURE ALONG 26W...SCATTERED MODERATE CONVECTION IS FROM 09N-
13N BETWEEN 30W-45W.

...DISCUSSION...

GULF OF MEXICO...

A MID TO UPPER-LEVEL TROUGH IS LOCATED IN THE WESTERN GULF ALONG
96W. ANOTHER MID TO UPPER-LEVEL TROUGH IS MOVING ACROSS THE
SOUTHEASTERN UNITED STATES FROM WESTERN NORTH CAROLINA TO JUST S
OF LOUISIANA NEAR 28N94W. THESE FEATURES ARE SUPPORTING A PAIR
OF SURFACE TROUGHS ACROSS THE W AND NORTHERN GULF. THE FIRST
EXTENDS FROM 25N96W TO 21N97W WHILE THE OTHER ONE IS FROM 28N92W
TO 29N84W. ISOLATED CONVECTION IS OBSERVED ALONG THE TROUGH IN
THE W GULF WHILE SCATTERED MODERATE TO STRONG CONVECTION
PREVAILS ACROSS THE TROUGH OVER THE NORTHERN GULF MAINLY N OF
24N. A SURFACE HIGH IS NOTED ACROSS THE NE GULF CENTERED NEAR
29N87W. SCATTEROMETER DATA DEPICTS A LIGHT TO GENTLE
ANTICYCLONIC FLOW ACROSS THE EASTERN GULF WHILE A GENTLE SW FLOW
PREVAILS S OF 25N AND W OF 90W. OVER THE NEXT 24 HOURS...EXPECT
FOR THE SURFACE HIGH IS FORECAST TO MEANDER IN THE NE GULF.
CONVECTION WILL REMAIN POSSIBLE ACROSS THE NORTHERN GULF.

CARIBBEAN SEA...

AN UPPER-LEVEL LOW IS CENTERED OVER THE WESTERN CARIBBEAN AND
GULF OF HONDURAS NEAR 17N86W WHILE ANOTHER LOW IS CENTERED S OF
PUERTO RICO NEAR 17N67W. WITH THESE...A DIFFLUENT FLOW PREVAILS
ACROSS THE CENTRAL CARIBBEAN SUPPORTING SCATTERED MODERATE
CONVECTION BETWEEN 77W-83W. SCATTERED MODERATE CONVECTION IS
ALSO OBSERVED OVER CUBA AND JAMAICA MOVING OFFSHORE AFFECTING
THEIR ADJACENT WATERS. FAIR WEATHER PREVAILS ACROSS THE
REMAINDER OF THE BASIN. SCATTEROMETER DATA DEPICTS GENTLE TO
MODERATE TRADES PREVAILING ACROSS THE BASIN. EXPECT FOR WINDS TO
PULSE TO FRESH TO STRONG EACH NIGHT AS THE PRESSURE GRADIENT
DIURNALLY TIGHTENS.

...HISPANIOLA...

MOSTLY CLEAR SKIES ARE NOTED ON VISIBLE SATELLITE IMAGERY
LARGELY DUE TO RELATIVELY DRY CONDITIONS ALOFT AND OVERALL
STABILITY PROVIDED BY THE SUBTROPICAL RIDGE ANCHORED ACROSS THE
SW ATLANTIC REGION. OVER THE NEXT 24 HOURS...EXPECT DAYTIME
HEATING AND HIGH MOISTURE CONTENT TO INDUCE SCATTERED CONVECTION
IN THE AFTERNOON.

ATLANTIC OCEAN...

AN UPPER-LEVEL RIDGE EXTENDS FROM THE FLORIDA PENINSULA NEAR
27N80W TO 25N64W. A 1012 MB SURFACE LOW IS CENTERED NEAR 30N80W
AND EXTENDING A SURFACE TROUGH FROM ITS CENTER TO 29N71W.
ISOLATED CONVECTION IS OBSERVED ALONG THIS BOUNDARY. ANOTHER
SURFACE TROUGH WITH ISOLATED CONVECTION EXTENDS FROM 28N67W TO
31N60W. TO THE S...A 1016 MB SURFACE HIGH IS NEAR 24N62W. A WEAK
1012 MB SURFACE LOW IS CENTERED NEAR 27N52W WITH NO SIGNIFICANT
CONVECTION. T.S FRED PREVAILS ACROSS THE E ATLANTIC. FOR MORE
INFORMATION PLEASE REFER TO THE SECTION ABOVE. THE REMAINDER OF
THE BASIN IS DOMINATED BY A SURFACE RIDGE AND FAIR WEATHER.

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

$$

ERA



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