[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201720
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN SEP 20 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...

AS OF 20/1500 UTC...TROPICAL STORM IDA IS CENTERED NEAR 17.3N
44.8W OR ABOUT 970 NM E OF THE LEEWARD ISLANDS MOVING WNW AT 11
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM
SUSTAINED WIND SPEED IS 40 KT WITH GUSTS UP TO 50 KT. SCATTERED
MODERATE CONVECTION IS FROM 13N TO 19N BETWEEN 38W AND 45W.
PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM WESTERN AFRICA NEAR 12N16W TO
08N33W. SCATTERED MODERATE CONVECTION IS W OF 18W WITHIN 150 NM
OF THE TROUGH AXIS. SOME OF THIS CONVECTION IS ASSOCIATED WITH A
TROPICAL WAVE THAT IS ABOUT TO EMERGE OFF THE COAST OF AFRICA.
ISOLATED MODERATE CONVECTION IS WITHIN 150 NM S OF THE TROUGH
AXIS E OF 21W.

...DISCUSSION...

GULF OF MEXICO...

A SHARP UPPER TROUGH EXTENDS ALONG THE OFFSHORE WATERS OF THE
EASTERN US TO S FL TO THE S CENTRAL GULF NEAR
22N93W...SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 26N82W TO
25N90W. SCATTERED SHOWERS ARE WITHIN 50 NM OF THE TROUGH AXIS.
ANOTHER SURFACE TROUGH OF DIURNAL ORIGINS EXTENDS FROM 22N93W TO
18N94W. NO DEEP CONVECTION IS NOTED WITH THIS TROUGH. A 1006 MB
HIGH IS CENTERED NEAR 29N91W. MAINLY GENTLE TO MODERATE SURFACE
WINDS COVER THE GULF TODAY. OVER THE NEXT 24 HOURS A COLD FRONT
WILL ENTER THE NE GULF. DRY AIR WILL LIMIT CONVECTION ASSOCIATED
WITH THIS FRONTAL BOUNDARY. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL REMAIN POSSIBLE WITH THE E GULF SURFACE
TROUGH THROUGH MONDAY.

CARIBBEAN SEA...

UPPER LEVEL DIFFLUENCE ASSOCIATED WITH UPPER LEVEL RIDGING
SUPPORTS ISOLATED MODERATE CONVECTION OVER THE NW CARIBBEAN FROM
15N TO 20N W OF 83W...INCLUDING BELIZE. AN UPPER LOW CENTERED
NEAR 15N77W SUPPORTS SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS FROM 13N TO 15N BETWEEN 75W AND 78W. SCATTERED
THUNDERSTORMS ARE S OF 10N BETWEEN 78W AND THE COAST OF COLOMBIA
ASSOCIATED WITH THE E PACIFIC MONSOON TROUGH. GENTLE TO MODERATE
TRADE WINDS ARE OVER THE CARIBBEAN N OF A LINE FROM 20N87W TO
15N61W. MODERATE TO FRESH TRADE WINDS ARE S OF THIS LINE. OVER
THE NEXT 24 HOURS CONVECTION WILL CONTINUE OVER THE WESTERN
CARIBBEAN.

...HISPANIOLA...

LOW LEVEL MOISTURE COMBINED WITH DAYTIME HEATING WILL RESULT IN
ISOLATED THUNDERSTORMS OVER THE ISLAND THIS AFTERNOON AND
EVENING. GENERALLY FAIR WEATHER IS EXPECTED OVERNIGHT TONIGHT. A
SIMILAR PATTERN IS FORECAST FOR MONDAY AND MONDAY NIGHT.

ATLANTIC OCEAN...

A SHARP UPPER TROUGH ALONG THE EASTERN US COAST SUPPORTS A 1007
MB LOW NEAR 31N75W. A SURFACE TROUGH EXTENDS FROM THIS LOW TO
26N77W TO 23N81W. THE COMBINATION OF ASCENT ASSOCIATED WITH THE
UPPER TROUGH AND CONVERGENCE WITH THE SURFACE TROUGH SUPPORTS
SCATTERED THUNDERSTORMS WITHIN 300 NM E OF THE TROUGH N OF 26N
AND WITHIN 100 NM OF THE TROUGH AXIS S OF 26N. A 1009 MB SURFACE
LOW WHICH IS THE REMNANTS OF T.D. NINE IS CENTERED NEAR 19N52W.
A SURFACE TROUGH EXTENDS N FROM THE LOW TO NEAR 28N51W. UPPER
LEVEL DIFFLUENCE ON THE NE SIDE OF AN UPPER LOW COMBINED WITH
THE MOISTURE ASSOCIATED WITH THE SURFACE TROUGH SUPPORTS
SCATTERED MODERATE CONVECTION FROM 22N TO 31N BETWEEN 42W AND
54W. TROPICAL STORM IDA IS OVER THE CENTRAL ATLC. PLEASE REFER
TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS. FARTHER
EAST...A SURFACE TROUGH EXTENDS FROM 27N25W TO 22N23W. NO DEEP
CONVECTION IS NOTED. OVER THE NEXT 24 HOURS CONVECTION WILL
CONTINUE OVER THE CENTRAL ATLC ASSOCIATED WITH THE REMNANTS OF
T.D. NINE...THE SURFACE TROUGH...AND IDA. CONVECTION WILL ALSO
CONTINUE BETWEEN BERMUDA AND THE BAHAMAS.

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

$$

LATTO
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