Tropical Weather Discussion
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000
AXNT20 KNHC 161036
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...SPECIAL FEATURES...

HURRICANE EDOUARD IS CENTERED NEAR 30.2N 57.3W AT 16/0900Z UTC
OR ABOUT 405 NM E-SE OF BERMUDA MOVING N-NW AT 11 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 963 MB. MAXIMUM SUSTAINED WIND SPEED
IS 95 KT WITH GUSTS TO 115 KT. SLIGHT STRENGTHENING IS POSSIBLE
DURING THE NEXT 24 HOURS... BUT THEN WEAKENING IS EXPECTED
WEDNESDAY AND WEDNESDAY NIGHT. NUMEROUS STRONG CONVECTION IS
FROM 29N-31N BETWEEN 56W-58W. SCATTERED MODERATE CONVECTION AND
ISOLATED TSTMS ARE ELSEWHERE FROM 27N-33N BETWEEN 55W-62W. 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 18N27W TO A 1010 MB LOW EMBEDDED IN THE MONSOON
TROUGH NEAR 13N27W TO 9N27W. THE APPROXIMATELY WESTWARD
TRANSLATION SPEED OF THE WAVE IS 15-20 KT. A SIGNIFICANT
REDUCTION OF MOISTURE DURING THE LAST 24 HOURS IS NOTED IN THE
SSMI TPW IMAGERY...WHICH ALONG STRONG DEEP LAYER ENVIRONMENTAL
SHEAR ON THE NORTHERN WAVE ENVIRONMENT SUPPORT LACK OF
CONVECTION.

TROPICAL WAVE IS ON THE CENTRAL ATLC WITH AXIS EXTENDING FROM
20N48W TO 10N49W...MOVING WEST AT 20 KT. INTRUSION OF SAHARAN
DRY AIR INTO THE SYSTEM KEEP IT MAINLY CONVECTIVE FREE EXCEPT IN
THE NORTHERN WAVE ENVIRONMENT WHERE A REGION OF DEEP LAYER
MOISTURE COINCIDES WITH A ZONE OF UPPER-LEVEL DIFFLUENCE THAT
SUPPORTS SCATTERED MODERATE CONVECTION AND TSTMS FROM 16N-21N
BETWEEN 48W-52W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO
A 1010 MB LOW NEAR 13N27W TO 12N38W 10N45W. THE ITCZ AXIS
EXTENDS FROM 10N45W TO THE COAST OF GUYANA NEAR 7N58W. BESIDES
THE CONVECTION ASSOCIATED WITH THE WAVES...SCATTERED MODERATE
CONVECTION IS FROM 7N-10N E OF 21W...AND FROM 3N-13N BETWEEN 25W-
41W.

...DISCUSSION...

GULF OF MEXICO...

OVERALL INSTABILITY CONTINUES ACROSS GREAT PORTIONS OF THE BASIN
DUE TO DEEP LAYER TROUGHINESS IN THE WESTERN BASIN AND ABUNDANT
MOISTURE BEING ADVECTED FROM THE CARIBBEAN. AN INVERTED TROUGH
IN THE MIDDLE TO UPPER LEVELS SUPPORT A SURFACE TROUGH ALONG
27N96W TO 18N94W. NUMEROUS MODERATE/ISOLATED STRONG CONVECTION
AND TSTMS ARE IN THE BAY OF CAMPECHE S OF 21N. MIDDLE TO UPPER
LEVEL RIDGING DOMINATES ELSEWHERE IN THE BASIN SUPPORTING A
SURFACE RIDGE OVER THE E-NE BASIN THAT IS ANCHORED BY A 1018 MB
HIGH ON THE SW N ATLC NEAR 29N75W. UPPER-LEVEL DIFFLUENCE
ENHANCES SCATTERED MODERATE CONVECTION AND TSTMS WITHIN 110 NM
OF THE NORTHERN GULF COASTLINE EAST OF 93W. A STATIONARY FRONT
IS ACROSS THE S-SE CONUS...A PRE-FRONTAL TROUGH IS ALONG 30N81W
SW TO 30N85W TO 28N92W. THE SURFACE TROUGH WILL PREVAIL ON THE
WESTERN BASIN THE NEXT TWO DAYS WHILE HIGH PRESSURE WILL
DOMINATE ELSEWHERE. THE FORMER STATIONARY FRONT ACROSS THE
SOUTHERN STATES WILL TRANSITION INTO A COLD FRONT THAT WILL MOVE
ACROSS FLORIDA THURSDAY.

CARIBBEAN SEA...

A WEAK PRESSURE GRADIENT ACROSS MOST OF THE REGION IS SUPPORTING
TRADES OF 10-15 KT. EXCEPT FOR THE NW AND SW CARIBBEAN WHERE
ABUNDANT MOISTURE AND UPPER-LEVEL DIFFLUENCE PREVAIL SUPPORTING
CONVECTION...THE REMAINDER BASIN IS BEING INFLUENCED BY DRY AIR
AND STRONG DEEP LAYER ENVIRONMENTAL SHEAR...THUS SUPPORTING
MAINLY FAIR WEATHER. SCATTERED SHOWERS ARE ON THE NW BASIN FROM
15N-21N BETWEEN W OF 78W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION AND TSTMS ARE S OF 14N W OF 76W. THE NEXT TROPICAL
WAVE IS FORECAST TO MOVE ACROSS THE EASTERN CARIBBEAN WEDNESDAY
THROUGH THURSDAY.

...HISPANIOLA...

MODERATE DEEP LAYER MOISTURE IN THE REGION ALONG WITH MIDDLE TO
UPPER LEVEL DIFFLUENCE ENHANCE 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 TO SUPPORT A 1018 MB
HIGH NEAR 29N75W. OTHERWISE...AN UPPER LEVEL TROUGH IN THE
EASTERN ATLC SUPPORT A COLD FRONT THAT IS ANALYZED FROM 30N16W
SW TO 27N25W WITH NO CONVECTION ASSOCIATED WITH IT.

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

$$
NR



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