[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251825
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI SEP 25 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL DEPRESSION IDA AT 25/1500 UTC IS NEAR
22.1N 45.0W. IDA IS MOVING TOWARD THE N...OR 355 DEGREES...AT 4
KT. THE MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS IS 25 KNOTS WITH GUSTS TO 35 KNOTS. PUBLIC
ADVISORIES ABOUT TROPICAL DEPRESSION IDA ARE BEING ISSUED UNDER
THE WMO HEADER WTNT35 KNHC...AND UNDER THE AWIPS HEADER
MIATCPAT5. FORECAST/ADVISORIES ABOUT TROPICAL DEPRESSION IDA ARE
BEING ISSUED UNDER THE WMO HEADER WTNT25 KNHC...AND UNDER THE
AWIPS HEADER MIATCMAT5. ISOLATED MODERATE CONVECTION IS CONFINED
TO THE EASTERN SEMICIRCLE OF THE SYSTEM FROM 15N TO 24N BETWEEN
38W AND 45W.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE E ATLC WITH AN AXIS EXTENDING FROM
NEAR 13N30W TO 03N30W...MOVING W AT 5 TO 10 KT OVER THE PAST 24
HOURS. A BROAD 700 MB TROUGH IS INDICATED BY MODEL FIELDS
BETWEEN 22N AND 32W. DEEP MOISTURE IS CONFINED S OF 13N IN THE
ENVIRONMENT OF THE WAVE. SCATTERED MODERATE CONVECTION IS FROM
05N TO 13N BETWEEN 28W AND 33W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SENEGAL NEAR 13N17W
AND EXTENDS OVER ATLC WATERS TO 09N28W. THE ITCZ BEGINS W OF A
TROPICAL WAVE NEAR 07N32W TO 08N45W. OTHER THAN CONVECTION
ASSOCIATED WITH THE TROPICAL WAVE...ISOLATED MODERATE CONVECTION
IS FROM 06N TO 16N BETWEEN 22W AND 28W.

...DISCUSSION...

GULF OF MEXICO...

A SURFACE TROUGH EXTENDS OVER THE CENTRAL GULF FROM NEAR 26N89W
TO 21N92W. THE COMBINATION OF THIS SURFACE TROUGH AND LOW LEVEL
SPEED SHEAR ARE SUPPORTING SCATTERED THUNDERSTORMS FROM 23N TO
29N BETWEEN 83W AND 97W. THERMODYNAMIC INFLUENCES SUPPORT
ISOLATED THUNDERSTORMS OFFSHORE THE MEXICO COAST FROM 18N TO 22N
W OF 93W. MODERATE NE SURFACE WINDS COVER THE GULF N OF 27N.
GENTLE E TO NE WINDS COVER MUCH OF THE REMAINDER OF THE GULF.
OVER THE NEXT 24 HOURS AN UPPER TROUGH OVER TX IS EXPECTED TO
CLOSE OFF AND INTERACT WITH THE SURFACE TROUGH OVER THE GULF TO
SUPPORT CONVECTION MAINLY W OF 85W ACROSS THE GULF BASIN. OVER
THE WEEKEND...ADDITIONAL MOISTURE ASSOCIATED WITH A SURFACE
TROUGH OVER THE NW CARIBBEAN WILL LIKELY BRING CONVECTION ACROSS
THE CENTRAL AND EASTERN GULF...WITH ONGOING CONVECTION
ASSOCIATED WITH THE UPPER LOW OVER THE WESTERN GULF.

CARIBBEAN SEA...

UPPER LEVEL DIFFLUENCE OVER THE NW CARIBBEAN COMBINED WITH DEEP
MOISTURE AND A SURFACE TROUGH FROM 20N85W TO 16N86W SUPPORTS A
CLUSTER OF MODERATE TO STRONG CONVECTION FROM 16N TO 19N BETWEEN
85W AND 89W. THE DEEP MOISTURE EXTENDS ACROSS THE ENTIRE W
CARIBBEAN...WHICH SUPPORTS SCATTERED THUNDERSTORMS S OF 16N
BETWEEN 77W AND 85W. DRIER AIR COVERS THE CENTRAL AND EASTERN
CARIBBEAN...INHIBITING CONVECTION. MODERATE TO FRESH TRADE WINDS
COVER THE CENTRAL CARIBBEAN S OF 17N BETWEEN 63W AND 78W...AND
WITHIN 100 NM OF THE SURFACE TROUGH. GENTLE TO MODERATE TRADE
WINDS COVER THE REMAINDER OF THE CARIBBEAN BASIN. MODELS ARE
FORECASTING CONVECTION ASSOCIATED WITH THE SURFACE TROUGH OVER
THE NW CARIBBEAN TO CONTINUE AND POSSIBLY INCREASE THROUGH THE
WEEKEND AS THE TROUGH DRIFTS VERY SLOWLY NORTHWARD.

...HISPANIOLA...

AN UPPER LOW NE OF HISPANIOLA OVER THE SW NORTHERN ATLC HAS AN
UPPER TROUGH AXIS THAT EXTENDS JUST E OF THE ISLAND. FLOW AROUND
THIS TROUGH COMBINED WITH SHALLOW MOISTURE WILL SUPPORT ISOLATED
THUNDERSTORMS ACROSS HISPANIOLA MAINLY DURING THE AFTERNOON AND
EVENING TODAY AND AGAIN ON SATURDAY.

ATLANTIC OCEAN...

A SURFACE TROUGH EXTENDS OFFSHORE OF GA/FL FROM 31N79W TO 25N80W
SUPPORTING SCATTERED MODERATE CONVECTION FROM 24N TO 31N BETWEEN
75W AND 79W. AN UPPER LOW CENTERED NEAR 23N68W SUPPORTS
SCATTERED MODERATE CONVECTION FROM 20N TO 29N BETWEEN 59W AND
71W. TROPICAL DEPRESSION IDA IS OVER THE CENTRAL ATLC. PLEASE
REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS. A
TROPICAL WAVE IS OVER THE EASTERN ATLC. PLEASE REFER TO THE
TROPICAL WAVES SECTION FOR MORE DETAILS. A 1021 MB HIGH IS
CENTERED NEAR 31N32W. OVER THE NEXT 24 HOURS CONVECTION WILL
PERSIST NEAR THE UPPER LOW OVER THE W ATLC.

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

$$
LATTO
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