Tropical Weather Discussion
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000
AXNT20 KNHC 161751
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE SEP 16 2014

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...

HURRICANE EDOUARD IS CENTERED NEAR 31.1N 57.8W AT 16/1500 UTC OR
ABOUT 405 NM E-SE OF BERMUDA MOVING N-NW AT 11 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 955 MB. MAXIMUM SUSTAINED WINDS ARE
NOW 100 KT WITH GUSTS TO 120 KT...MAKING EDOUARD THE FIRST MAJOR
HURRICANE OF THE 2014 SEASON. LITTLE CHANGE IN INTENSITY IS
EXPECTED DURING THE NEXT 24 HOURS...WITH WEAKENING EXPECTED
WEDNESDAY NIGHT AND THURSDAY. NUMEROUS STRONG CONVECTION IS FROM
29N-31N BETWEEN 56W-58W. SCATTERED TO NUMEROUS STRONG CONVECTION
WAS WITHIN 75 NM OF THE CENTER. SCATTERED MODERATE ISOLATED
STRONG CONVECTION WAS NOTED ELSEWHERE WITHIN 180 NM OF THE
CENTER WITH THE STRONGEST ACTIVITY IN THE SOUTHERN SEMICIRCLE.
SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS WEST OF THE CAPE VERDE ISLANDS WITH AXIS
EXTENDING FROM 18N28W TO A 1009 MB LOW EMBEDDED IN THE MONSOON
TROUGH NEAR 13N29W TO 10N29W. THE WAVE WAS MOVING WEST AT 15-20
KT. THE WAVE WAS RETAINING SOME MOISTURE AS INDICATED BY THE
GOES-R SEVIRI AIRMASS PRODUCT. HOWEVER UPPER LEVEL CLOUD MOTIONS
INDICATED STRONG UPPER LEVEL SHEAR OVER THE NORTHERN PORTION OF
THE WAVE.

TROPICAL WAVE IS ON THE CENTRAL ATLC WITH AXIS EXTENDING FROM
20N50W TO 10N50W...MOVING WEST AT 20 KT. SOME CONVECTION WAS
NOTED WITHIN 60 NM EITHER SIDE OF THE WAVE AXIS N OF 18N DESPITE
THE INTRUSION OF SAHARAN DRY AIR INTO THE SYSTEM FROM THE
NORTHEAST PER GOES-R SEVIRI AIRMASS PRODUCT. ADDITIONALLY THE
CONVECTION WAS DEVELOPING WITHIN A ZONE OF UPPER-LEVEL
DIFFLUENCE.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 9N15W TO
A 1009 MB LOW NEAR 13N29W TO 11N35W TO 12N41W. THE ITCZ AXIS
EXTENDS FROM 12N41W TO 10N50W TO TRINIDAD. BESIDES THE
CONVECTION ASSOCIATED WITH THE WAVES...SCATTERED MODERATE TO
STRONG CONVECTION WAS NOTED WITHIN 120-180 NM S OF THE ITCZ
BETWEEN 31W-38W.

...DISCUSSION...

GULF OF MEXICO...

OVERALL INSTABILITY CONTINUES ACROSS MUCH OF THE NORTHERN HALF
OF THE GULF OF MEXICO IN THE VICINITY  OF A SURFACE TROUGH WHICH
EXTENDS FROM CEDAR KEY FLORIDA TO THE MOUTH OF THE MISSISSIPPI
RIVER IN LOUISIANA TO NEAR LAKE CHARLES. SCATTERED TO NUMEROUS
STRONG THUNDERSTORMS WERE NOTED WITHIN 60-90 NM OF THE TROUGH
AND WERE AFFECTING VAST STRETCHES OF THE COASTAL WATERS AREAS
FROM THE FLORIDA PANHANDLE TO LOUISIANA. GOES-R GRIDDED LIGHTING
DATA INDICATED THE MOST ACTIVE CONVECTION WAS WITHIN THE COASTAL
WATERS OF ALABAMA AND SOUTH-CENTRAL LOUISIANA. AN INVERTED
TROUGH IN THE MIDDLE TO UPPER LEVELS SUPPORTED A SURFACE TROUGH
ALONG 25N97W TO 18N95W. SCATTERED TO NUMEROUS MODERATE AND
STRONG CONVECTION WERE NOTED IN THE BAY OF CAMPECHE S OF 22N.
MIDDLE TO UPPER LEVEL RIDGING DOMINATES ELSEWHERE IN THE BASIN
SUPPORTING A SURFACE RIDGE OVER THE E-NE BASIN THAT IS ANCHORED
BY A 1020 MB HIGH NEAR TAMPA BAY FLORIDA. THE SURFACE TROUGH
WILL PREVAIL OVER THE WESTERN PORTION OF THE BASIN THE NEXT TWO
DAYS WHILE HIGH PRESSURE WILL DOMINATE ELSEWHERE. A STATIONARY
FRONT ACROSS THE SOUTHERN STATES WILL TRANSITION INTO A COLD
FRONT THAT WILL MOVE INTO THE NE GULF AND FLORIDA THURSDAY.

CARIBBEAN SEA...

A FAIRLY WEAK PRESSURE GRADIENT EXISTS ACROSS MOST OF THE BASIN
REGION IS SUPPORTING TRADES OF 10-15 KT WITH THE EXCEPTION OF 15-
20 KT TRADES OVER THE SW CARIBBEAN AND THE GULF OF HONDURAS.
AXIS OF UPPER LEVEL TROUGH EXTENDS FROM EASTERN CUBA TO NE
HONDURAS WITH UPPER-LEVEL DIFFLUENCE SE OF THE TROUGH AXIS. THIS
IN CONJUNCTION WITH ABUNDANT MOISTURE ALONG THE MONSOON TROUGH
IS SUPPORTING SCATTERED STRONG CONVECTION OVER THE FAR SW
CARIBBEAN FROM 10N-13N BETWEEN 77W-80W. THE REMAINDER OF THE
BASIN IS BEING INFLUENCED BY DRY AIR AND STRONG DEEP LAYER
ENVIRONMENTAL SHEAR...THUS SUPPORTING MAINLY FAIR WEATHER.
SCATTERED SHOWERS AND TSTMS ARE NOTED BETWEEN JAMAICA AND SE
CUBA. THE NEXT TROPICAL WAVE IS FORECAST TO MOVE ACROSS THE
EASTERN CARIBBEAN THURSDAY INTO FRIDAY.

...HISPANIOLA...

MODERATE DEEP LAYER MOISTURE IN THE REGION ALONG WITH MIDDLE TO
UPPER LEVEL DIFFLUENCE EAST OF AN UPPER LEVEL TROUGH AXIS IS
ENHANCING SCATTERED SHOWERS OVER COASTAL WATERS AND ISOLATED
SHOWERS ACROSS THE ISLAND TONIGHT. BESIDES THE TYPICAL AFTERNOON
SHOWERS INDUCED BY DAYTIME HEATING...NO DEEP CONVECTION IS
EXPECTED ON TUESDAY.

ATLANTIC OCEAN...

HURRICANE EDOUARD AND TWO TROPICAL WAVES ARE THE MAIN FEATURES
ACROSS THE BASIN. SEE THE SPECIAL FEATURES AND TROPICAL WAVES
SECTIONS ABOVE. UPPER-LEVEL RIDGING ACROSS PORTIONS OF THE GULF
OF MEXICO EXTENDS NE INTO THE SW N ATLC AND IS REFLECTED AT THE
SURFACE AS A 1020 MB HIGH NEAR 28N74W. OTHERWISE...AN UPPER
LEVEL TROUGH IN THE EASTERN ATLC SUPPORTS THE TAIL END OF A COLD
FRONT ANALYZED NEAR THE CANARY ISLANDS.

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

$$
COBB



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