[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041114
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED SEP 04 2013

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURE...
CONVECTIVE ACTIVITY ASSOCIATED WITH A 1008 MB LOW PRESSURE
CENTER NEAR 15N64W LOOKS BETTER ORGANIZED THIS MORNING. A
CLUSTER OF MODERATE CONVECTION AND TSTMS IS FROM 14N-17N BETWEEN
63W-65W. ELSEWHERE...SCATTERED SHOWERS ARE FROM 14N-19N BETWEEN
62W-67W. UPPER-LEVEL WINDS APPEAR FAVORABLE FOR SOME DEVELOPMENT
OVER THE NEXT FEW DAYS...BUT INTERACTION WITH THE LAND MASSES OF
HISPANIOLA AND PUERTO RICO COULD INHIBIT TROPICAL CYCLONE
FORMATION AS THE SYSTEM MOVES NORTHWESTWARD AT AROUND 10 MPH.
CURRENTLY...THIS SYSTEM HAS A MEDIUM CHANCE...30 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. REGARDLESS
OF TROPICAL CYCLONE FORMATION...LOCALLY HEAVY RAINFALL AND GUSTY
WINDS ARE EXPECTED TO AFFECT THE VIRGIN ISLANDS...AND SPREAD
OVER PUERTO RICO LATER TODAY.

...TROPICAL WAVES...
A TROPICAL WAVE ASSOCIATED WITH A 1011 MB LOW PRESSURE CENTER IS
MOVING ACROSS THE CAPE VERDE ISLANDS. ITS AXIS EXTENDS FROM
17N24W TO THE LOW CENTER NEAR 13N24W TO 09N24W AND IS MOVING
WEST NEAR 10 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE LOW
PRESSURE HAS BEEN DRAWING MOISTURE FROM THE MONSOON TROUGH WHICH
HAS ASSISTED IN THE DEVELOPMENT OF SMALL CLUSTERS OF MODERATE
CONVECTION SW OF THE LOW FROM 09N-12N BETWEEN 24W-31W. WIDELY
SCATTERED MODERATE CONVECTION PERSIST NE OF THE LOW FROM 16N-19N
BETWEEN 16W-22W.

A TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLC EXTENDING AN
AXIS FROM 24N44W TO 10N42W AND MOVING WEST NEAR 10 KT. METEOSAT
SAL TRACKING IMAGERY SHOW THIS WAVE IS BETWEEN TWO SAHARAN DRY
AIRMASSES WHICH ARE LIMITING CONVECTIVE ACTIVITY. TOTAL
PRECIPITABLE WATER IMAGERY SHOW THE WAVE AXIS IS EMBEDDED WITHIN
A FINE ELONGATED LINE OF MODERATE MOISTURE. ISOLATED SHOWERS ARE
WITHIN 120 NM EITHER SIDE OF THE AXIS FROM 22N-24N AND WITHIN
160 NM W OF THE AXIS FROM 14N-16N.

A TROPICAL WAVE IS APPROACHING THE LESSER ANTILLES. ITS AXIS
EXTENDS FROM 20N56W TO 12N59W AND IS MOVING W-NW NEAR 10 KT.
TOTAL PRECIPITABLE WATER IMAGERY SHOW THAT MOISTURE CONTINUES TO
AMPLIFY WITHIN THE WAVE ENVIRONMENT ASSISTING IN THE GENERATION
OF NUMEROUS MODERATE CONVECTION AND TSTMS FROM 15N-19N BETWEEN
56W-60W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 11N-21N
BETWEEN 53W-60W.

A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN SEA WITH
AXIS EXTENDING FROM 24N72W TO THE WINDWARD PASSAGE NEAR 18N74W
TO 10N74W IN NORTHERN COLOMBIA. THE ZONE OF UPPER LEVEL
DIFFLUENCE HAS SHIFTED WESTWARD AND NOW SHOWERS AND TSTMS
CONCENTRATE OVER THE WINDWARD PASSAGE AND THE TRENCH BETWEEN
JAMAICA AND SE CUBA.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E
TROPICAL ATLC NEAR 19N16W AND CONTINUES ALONG 12N19W TO 06N27W
TO 07N36W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVES ALREADY DISCUSSED...SCATTERED MODERATE CONVECTION IS FROM
07N-11N E OF 17W...FROM 05N-09N BETWEEN 25W-29W AS WELL AS FROM
05N-08N BETWEEN 45W-51W.

...DISCUSSION...

THE GULF OF MEXICO...
A SURFACE TROUGH EXTENDS FROM 26N90W TO 22N92W TO A 1010 MB LOW
IN THE BAY OF CAMPECHE NEAR 19N93W. A REGION OF MIDDLE-LEVEL
DIFFLUENCE IS OVER THE WESTERN BAY OF CAMPECHE WHICH IS
ENHANCING A LINE OF SCATTERED SHOWERS AND TSTMS S OF 23N W OF
94W. A COL OR AREA OF LOW PRESSURE IN THE UPPER-LEVELS IS
ENHANCING SIMILAR CONVECTION EAST OF THE TROUGH OVER THE EASTERN
YUCATAN PENINSULA. THE SOUTHERN EXTENSION OF A NARROW UPPER
LEVEL TROUGH ALONG THE EASTERN CONUS EXTENDS TO THE NORTH-
CENTRAL GULF AND SUPPORTS SCATTERED SHOWERS FROM 24N-27N BETWEEN
88W-93W. A 1015 MB HIGH PRESSURE CENTER DEVELOPED OVER THE NE
GULF NEAR 29N85W. THE TROUGH/AREA OF LOW PRESSURE WILL CONTINUE
TO MOVE WESTWARD OVER THE BAY OF CAMPECHE AND IS EXPECTED TO
PERSIST THROUGH FRIDAY AFTERNOON.

THE CARIBBEAN SEA...
SCATTERED MODERATE CONVECTION IS OVER THE FAR NW CARIBBEAN SEA S
OF 22N W OF 85W BEING ENHANCED BY A COL/AREA OF LOW PRESSURE
ALOFT. AN INVERTED TROUGH IS BETWEEN THE WINDWARD PASSAGE AND
CENTRAL CUBA. THE WESTERN PERIPHERY OF AN UPPER LEVEL HIGH
SPREADS ACROSS THE EASTERN CARIBBEAN TO GENERATE DIFFLUENCE
ALOFT OVER THE WINDWARD PASSAGE AND THE TRENCH BETWEEN SE CUBA
AND JAMAICA...THUS GENERATING SHOWERS AND TSTMS IN THAT REGION.
A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN SEA WITH
AXIS EXTENDING FROM 24N72W TO THE WINDWARD PASSAGE NEAR 18N74W
TO 10N74W IN NORTHERN COLOMBIA. SCATTERED MODERATE CONVECTION IS
OVER THE SOUTHERN BASIN S OF 13N E OF 80W ASSOCIATED WITH THE
MONSOON TROUGH AND SOUTHERN REGION OF THE TROPICAL WAVE.
CONVECTIVE ACTIVITY ASSOCIATED WITH A 1008 MB LOW PRESSURE
CENTER NEAR 15N64W LOOKS BETTER ORGANIZED THIS MORNING. A
CLUSTER OF MODERATE CONVECTION AND TSTMS IS FROM 14N-17N BETWEEN
63W-65W. ELSEWHERE...SCATTERED SHOWERS ARE FROM 14N-19N BETWEEN
62W-67W. SEE THE SPECIAL FEATURE SECTION FOR MORE INFORMATION
ABOUT THIS INVEST AREA.

HISPANIOLA...
UPPER LEVEL DIFFLUENCE OVER THE REGION CONTINUES TO GENERATE
CLOUDINESS AND ISOLATED SHOWERS ACROSS THE ISLAND. HEAVY
RAINSHOWERS ARE EXPECTED TO DEVELOP EARLY THURSDAY ASSOCIATED
WITH THE CURRENT INVEST AREA IN THE EASTERN CARIBBEAN.

THE ATLANTIC OCEAN...
BESIDES THE TROPICAL WAVES ALREADY DISCUSSED...SURFACE RIDGING
ANCHORED BY A SET OF HIGH PRESSURE CENTERS N OF THE AREA
DOMINATES THE REMAINDER BASIN N OF 23N WHICH ALONG WITH DRY
STABLE AIR SUPPORTS FAIR WEATHER.

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

$$
NR

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