Tropical Weather Discussion
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000
AXNT20 KNHC 022336
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED SEP 02 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 STORM FRED IS CENTERED NEAR 20.3N 31.8W AT 02/2100 UTC
OR ABOUT 512 NM WNW OF THE CAPE VERDE ISLANDS MOVING WNW AT 9
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM
SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. A CLUSTER OF
MODERATE CONVECTION EXTENDS FROM 20N-23N BETWEEN 28W-32W. SEE
THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AXIS EXTENDING
17N45W TO 08N46W...MOVING W AT AROUND 10-15 KT. THE WAVE
COINCIDES WITH 700 MB TROUGHING BETWEEN 40W-50W. SCATTERED
MODERATE CONVECTION IS OBSERVED IN THE PROXIMITY OF THE MONSOON
TROUGH S OF 10N BETWEEN 44W-48W.

A TROPICAL WAVE IS MOVING ACROSS THE CARIBBEAN WITH AXIS
EXTENDING FROM 18N76W TO 10N80W MOVING W AT 20-25 KT. THE WAVE
COINCIDES WITH RELATIVELY BROAD 700 MB TROUGHING BETWEEN 70W-
80W. THE SHOWER ACTIVITY SURROUNDING THIS WAVE IS SUPPORTED BY
UPPER-LEVEL DIFFLUENCE S OF 15N AND W OF 79W AND THE PROXIMITY
OF THE MONSOON TROUGH S OF 10N.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
13N17W TO 06N51W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM THAT POINT TO 10N72W. ASIDE FROM CONVECTION
ASSOCIATED WITH THE TROPICAL WAVE ALONG 46W...SCATTERED MODERATE
CONVECTION IS FROM 09N-11N BETWEEN 22W-44W.

...DISCUSSION...

GULF OF MEXICO...

A MID TO UPPER-LEVEL LOW IS CENTERED OVER THE NW GULF NEAR
27N95W. THE LOW AND ASSOCIATED TROUGHING IS PROVIDING MUCH OF
THE WESTERN PORTION OF THE BASIN WITH SOUTH-SOUTHWESTERLY FLOW
ALOFT MAINLY W OF 93W. TO THE SE...AN UPPER-LEVEL HIGH IS
CENTERED OVER THE FLORIDA PENINSULA NEAR 28N83W. THE UPPER-LEVEL
DIFFLUENCE GENERATED BY THESE 2 FEATURES IS SUPPORTING SCATTERED
MODERATE CONVECTION ACROSS THE NORTHERN GULF...MAINLY N OF 24N.
A SURFACE TROUGH EXTENDS ACROSS THE NW GULF FROM 26N98W TO
29N89W. SCATTEROMETER DATA DEPICTS A GENTLE TO MODERATE
ANTICYCLONIC FLOW ACROSS THE BASIN AS A SURFACE RIDGE EXTENDS
FROM THE ATLANTIC W REACHING THE GULF WATERS. OVER THE NEXT 24
HOURS...THE SURFACE RIDGE WILL PREVAIL ACROSS THE AREA THEREFORE
A SIMILAR WEATHER REGIME IS EXPECTED.

CARIBBEAN SEA...

AN UPPER-LEVEL LOW IS CENTERED NEAR 17N81W AND EXTENDING ACROSS
THE WESTERN HALF OF THE BASIN. AN AREA OF UPPER-LEVEL DIFFLUENCE
PREVAILS S OF 15N IS SUPPORTING SCATTERED MODERATE CONVECTION
ACROSS THE S CARIBBEAN AND PORTIONS OF NICARAGUA AND HONDURAS.
SCATTERED CONVECTION IS OBSERVED ACROSS THE GREATER ANTILLES
MOSTLY DUE TO DIURNAL HEATING COMBINED WITH HIGH MOISTURE
CONTENT. SCATTEROMETER DATA DEPICTS GENTLE TO MODERATE TRADES
PREVAILING ACROSS THE BASIN EXCEPT S OF 14N BETWEEN 71W-76W
WHERE MODERATE TO FRESH WINDS ARE REPORTED. OVER THE NEXT 24
HOURS...EXPECT SIMILAR WEATHER CONDITIONS TO PREVAIL. BOTH THE
TROPICAL WAVE AND THE UPPER-LEVEL LOW WILL CONTINUE MOVING W
SUPPORTING CONVECTION.

...HISPANIOLA...

CURRENTLY...SCATTERED MODERATE CONVECTION IS OBSERVED ACROSS THE
WESTERN PORTION OF THE ISLAND MAINLY DUE TO DAYTIME HEATING AND
HIGH LOW-LEVEL MOISTURE. LITTLE CHANGE IN SYNOPTIC CONDITIONS IS
EXPECTED WITHIN THE NEXT 24 HOURS.

ATLANTIC OCEAN...

AN UPPER-LEVEL ANTICYCLONIC CIRCULATION IS ANCHORED NW FLORIDA
AND EXTENDING E ACROSS THE W ATLANTIC THROUGH 65W. AT THE
SURFACE...A PAIR OF 1019 MB AND 1018 MB SURFACE HIGHS PREVAIL
NEAR 27N77W AND 27N66W. TO THE E...A 1011 MB SURFACE LOW IS
LOCATED NEAR 29N52W AND EXTENDING A SURFACE TROUGH FROM ITS
CENTER TO 25N61W. ISOLATED MODERATE CONVECTION IS OBSERVED ALONG
THIS TROUGH. A TROPICAL WAVE AS WELL AS T.S. FRED ARE MOVING
ACROSS THE EASTERN HALF OF THE BASIN. FOR MORE INFORMATION ABOUT
THESE FEATURES...PLEASE REFER TO THE SECTIONS ABOVE.

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

$$

ERA



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