[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 241804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU SEP 24 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
1745 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM IDA AT 24/1500 UTC IS NEAR 20.2N
44.9W. IDA IS MOVING TOWARD THE NNE...OR 25 DEGREES...AT 4 KT.
THE MINIMUM CENTRAL PRESSURE IS 1005 MB. THE MAXIMUM SUSTAINED
WIND SPEEDS IS 30 KNOTS WITH GUSTS TO 40 KNOTS. PUBLIC
ADVISORIES ABOUT TROPICAL STORM IDA ARE BEING ISSUED UNDER THE
WMO HEADER WTNT35 KNHC...AND UNDER THE AWIPS HEADER MIATCPAT5.
FORECAST/ADVISORIES ABOUT TROPICAL STORM IDA ARE BEING ISSUED
UNDER THE WMO HEADER WTNT25 KNHC...AND UNDER THE AWIPS HEADER
MIATCMAT5. CONVECTIVE PRECIPITATION...SCATTERED MODERATE ENE OF
THE STORM CENTER FROM 19N TO 23N BETWEEN 37W AND 44W. SIMILAR
CONVECTION IS SSE OF IDA FROM 15N TO 19N BETWEEN 40W AND 49W.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE E ATLC NEAR THE CAPE VERDE ISLANDS
WITH AXIS ALONG 26W...MOVING W AT 5-10 KT WITHIN THE LAST 24
HOURS. CIRA LAYER PRECIPITABLE WATER IMAGERY INDICATE THE WAVE
IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT FROM THE SURFACE TO
850 MB...WITH SOME MOISTURE REACHING THE 700 MB. A DIFFLUENT
ENVIRONMENT E OF THE WAVE AXIS ALONG WITH THE MOISTURE SUPPORT
SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS FROM 08N TO 18N
E OF 23W. ISOLATED SHOWERS ARE WITHIN 75 NM EITHER SIDE OF THE
WAVE AXIS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SENEGAL NEAR 13N17W
AND EXTENDS OVER ATLC WATERS ALONG 10N24W TO 07N31W TO 07N38W.
NO ITCZ IS PRESENT AT THIS TIME. FOR INFORMATION ABOUT
CONVECTION SEE THE TROPICAL WAVES SECTION.

...DISCUSSION...

GULF OF MEXICO...

SURFACE LOW PRESSURE CONTINUES TO DOMINATE ACROSS THE GULF
WATERS S OF 28N. IN THE MIDDLE TO UPPER LEVELS...A CYCLONIC
CIRCULATION CENTERED OVER THE FLORIDA PANHANDLE EXTENDS A TROUGH
S TO A BASE OVER THE YUCATAN CHANNEL AND PENINSULA. OVER THE
WESTERN HALF OF THE CARIBBEAN SEA...AN UPPER RIDGE GENERATES A
DIFFLUENT WIND ENVIRONMENT OVER THE SE GULF AND THE FLORIDA
STRAITS THAT IN CONJUNCTION WITH LOW LEVEL MOISTURE ADVECTING
FROM THE ATLC AND THE CARIBBEAN SUPPORT SCATTERED SHOWERS AND
ISOLATED TSTMS S OF 26N E OF 89W. IN THE SW BASIN...A SURFACE
TROUGH EXTEND FROM 25N88W TO THE BAY OF CAMPECHE NEAR 18N95W
WITH POSSIBLE ISOLATED SHOWERS WITHIN 120 NM EITHER SIDE OF ITS
AXIS. ISOLATED SHOWERS ARE OBSERVED IN RADAR IMAGERY OVER
NORTHERN GULF OFFSHORE WATERS WHERE NE WINDS OF 15 KT DOMINATE.
VARIABLE LIGHTER WINDS ARE ELSEWHERE ACROSS THE BASIN. LOW
PRESSURE WILL PERSIST THE NEXT TWO DAYS. A SURFACE TROUGH
CURRENTLY OVER NICARAGUA IS EXPECTED TO DEVELOP A LOW PRESSURE
CENTER THAT IS EXPECTED TO ENTER THE S-SE GULF SUNDAY.

CARIBBEAN SEA...

OVER THE WESTERN HALF OF THE CARIBBEAN SEA...AN UPPER RIDGE
GENERATES A DIFFLUENT WIND ENVIRONMENT THAT IN CONJUNCTION WITH
ABUNDANT MOISTURE SUPPORT SCATTERED MODERATE CONVECTION AND
ISOLATED TSTMS W OF 78W WHERE A SURFACE TROUGH IS ANALYZED FROM
18N82W TO 11N83W. OFF THE COAST OF COLOMBIA...A 1005 MB LOW IS
CENTERED NEAR 10N76W CONNECTED TO THE EPAC MONSOON TROUGH THAT
ENHANCES A CLUSTER OF MODERATE TO STRONG CONVECTION WITH
ISOLATED TSTMS S OF 13N BETWEEN 75W AND 81W. AN UPPER LEVEL
CYCLONIC CIRCULATION IS OVER THE SW N ATLC NEAR 25N66W AND
EXTENDS A TROUGH S ACROSS THE EASTERN CARIBBEAN THAT ALONG WITH
SHALLOW MOISTURE SUPPORT SCATTERED SHOWERS AND TSTMS OVER
HISPANIOLA AND PUERTO RICO. SHOWERS ARE FORECAST TO PREVAIL OVER
THE SW AND NW CARIBBEAN AS THE LOW PRESSURE CENTER REMAIN
STATIONARY NEAR COLOMBIA THROUGH FRIDAY AND THE SURFACE TROUGH
MOVES W-NW TOWARD THE YUCATAN PENINSULA WITH AN ASSOCIATED LOW
PRESSURE CENTER TO DEVELOP FRIDAY NIGHT TO SATURDAY MORNING.

...HISPANIOLA...

AN UPPER LEVEL CYCLONIC CIRCULATION IS OVER THE SW N ATLC NEAR
25N66W AND EXTENDS A TROUGH S ACROSS THE EASTERN CARIBBEAN THAT
ALONG WITH SHALLOW MOISTURE SUPPORT SCATTERED SHOWERS AND TSTMS
OVER HISPANIOLA. SHOWERS ARE EXPECTED TO CEASE FRIDAY MORNING AS
THE UPPER LOW MOVES E TOWARD THE CENTRAL ATLC.

ATLANTIC OCEAN...

THE MAIN FEATURE IN THE BASIN IS TROPICAL STORM IDA ALREADY
DISCUSSED IN THE SPECIAL FEATURES SECTION ABOVE. OVER THE SW N
ATLC...A 1013 MB LOW PRESSURE CENTER IS OVER COASTAL WATERS OF
JACKSONVILLE FLORIDA NEAR 30N80W WITH ASSOCIATED SURFACE TROUGH
EXTENDING SSW TO 28N80W TO THE SE GULF OF MEXICO NEAR 25N83W. A
DIFFLUENT WIND ENVIRONMENT ALOFT OVER THIS REGION...BEING
GENERATED BY THE UPPER LOW CENTERED OVER THE FLORIDA PANHANDLE
AND A RIDGE EXTENDING ACROSS THE BAHAMAS...SUPPORT SCATTERED
HEAVY SHOWERS AND TSTMS N OF 20N W OF 73W. FARTHER EAST A MIDDLE
TO UPPER LOW CONTINUES TO ENHANCE SIMILAR CONVECTION FROM 20N TO
31N BETWEEN 57W AND 71W. THE REMAINDER BASIN IS BEING INFLUENCED
BY A SURFACE RIDGE CENTERED BY A 1025 MB HIGH NEAR 43N18W.

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

$$
NR
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