[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT AUG 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION FOUR FORMED AT 1800 UTC NEAR TURKS AND
CAICOS. AT 2100 UTC THE CENTER OF THE CYCLONE IS NEAR 21.8N
72.3W OR 220 NM ESE OF THE CENTRAL BAHAMAS...MOVING NORTHWEST AT
10 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB.
MAXIMUM SUSTAINED WINDS ARE 30 KT WITH GUSTS TO 40 KT. SOME
STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS...AND THE
DEPRESSION IS FORECAST TO BECOME A TROPICAL STORM BY SUNDAY.
SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 15N-
27N BETWEEN 65W-79W...INCLUDING PUERTO RICO AND HISPANIOLA. THE
DEPRESSION IS EXPECTED TO PRODUCE RAINFALL TOTALS OF 4 TO 8
INCHES OVER THE SOUTHEASTERN BAHAMAS...THE TURKS AND CAICOS
ISLANDS...AND THE CENTRAL BAHAMAS THROUGH TUESDAY...WITH
ISOLATED AMOUNTS AROUND 12 INCHES POSSIBLE. STORM TOTAL RAINFALL
AMOUNTS OF UP TO 12 INCHES ARE POSSIBLE IN PORTIONS OF
HISPANIOLA... WHERE THESE RAINS COULD PRODUCE LIFE-THREATENING
FLASH FLOODS AND MUDSLIDES...ESPECIALLY IN AREAS OF MOUNTAINOUS
TERRAIN. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS WEST OF THE CAPE VERDE ISLANDS WITH AXIS
EXTENDING FROM 20N25W TO 8N26W. THE WAVE IS EMBEDDED IN THE
MONSOON TROUGH WHERE HIGH LOW-LEVEL MOISTURE IS NOTED IN THE TPW
IMAGERY. THIS MOISTURE ALONG WITH UPPER-LEVEL DIVERGENCE IS
SUPPORTING SCATTERED MODERATE CONVECTION WITHIN 320 NM WEST OF
THE WAVE AXIS SOUTH OF 14N. ISOLATED SHOWERS ARE WITHIN 150 NM
EAST OF THE AXIS SOUTH OF 14N. HOWEVER...THE NORTHERN PART OF
THE WAVE IS BEING AFFECTED BY DRY SAHARAN AIR AND DUST...WHICH
IS LIMITING THE CONVECTION IN THAT REGION.

A TROPICAL WAVE IS ON THE CENTRAL ATLC WITH AXIS EXTENDING FROM
17N36W TO 9N36W...MOVING W AT 10 KT. NO DEEP CONVECTION IS
ASSOCIATED WITH THE WAVE AS DRY SAHARAN AIR AND DUST IS IN ITS
ENVIRONMENT.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR
13N16W AND CONTINUES ALONG 11N26W TO 10N38W. THE ITCZ BEGINS
NEAR 9N38W AND CONTINUES TO 9N49W 9N60W. BESIDES THE CONVECTION
ASSOCIATED WITH THE WAVES...NO OTHER AREAS OF SIGNIFICANT
CONVECTION ARE NOTED.

...DISCUSSION...

GULF OF MEXICO...

A MIDDLE TO UPPER LEVEL RIDGE IS ANCHORED BETWEEN THE TENNESSEE
AND OHIO VALLEY COVERING MOST OF THE EASTERN CONUS AND EXTENDING
SOUTH INTO THE GULF. THIS RIDGE ALOFT SUPPORT A SURFACE RIDGE
ACROSS THE GULF BEING ANCHORED BY A 1015 MB HIGH ON THE
COASTLINE OF LOUISIANA NEAR 29N92W...WHICH IS PROVIDING VARIABLE
WINDS OF 5-10 KT. MODERATE LOW-LEVEL MOISTURE IS ACROSS THE
BASIN WHICH IS ENHANCING ISOLATED SHOWERS S OF 25N W OF 90W AND
OVER THE SE GULF. A SURFACE TROUGH IS ACROSS NORTHERN FLORIDA
SUPPORTING SCATTERED HEAVY SHOWERS AND TSTMS EXTENDING OVER GULF
WATERS N OF 27N E OF 85W. SURFACE RIDGING WILL CONTINUE ACROSS
THE BASIN THROUGH MONDAY. MINIMAL CONVECTION IS EXPECTED THROUGH
THAT TIME...EXCEPT FOR THE FAR EASTERN GULF DURING MONDAY
EVENING/NIGHT WHERE A SURGE OF MOISTURE IS FORECAST TO SUPPORT
RAINSHOWERS.

CARIBBEAN SEA...

A MIDDLE TO LOWER LEVEL CYCLONIC CIRCULATION ANCHORED NEAR THE
INAGUA ISLANDS EXTENDS INTO THE CENTRAL CARIBBEAN SUPPORTING A
SURFACE TROUGH ALONG 19N77W TO 10N80W WHICH IS ENHANCING
SCATTERED SHOWERS AND TSTMS ON JAMAICA AND THE SW BASIN. THIS
MIDDLE TO LOWER LEVEL CYCLONE ALSO SUPPORTS TROPICAL DEPRESSION
FOUR ON THE SW N ATLC...WHICH RAINBANDS OF SCATTERED HEAVY
SHOWERS AND TSTMS ARE AFFECTING HISPANIOLA...PUERTO RICO AND
ADJACENT WATERS. THE DEPRESSION IS ALSO BRINGING SHOWERS AND
TSTMS TO CENTRAL AND EASTERN CUBA. OTHERWISE...VARIABLE WINDS OF
10-15 KT ARE ACROSS THE BASIN. RAINSHOWERS WILL CONTINUE TO
AFFECT PUERTO RICO THROUGH SUNDAY NIGHT WHILE RAINFALL FOR
HISPANIOLA AND EASTERN CUBA COULD EXTEND BEYOND MONDAY.

...HISPANIOLA...

THE RAINBANDS OF TROPICAL DEPRESSION FOUR CONTINUE TO AFFECT
HISPANIOLA WITH SCATTERED HEAVY SHOWERS AND TSTMS WITH POTENTIAL
OF CAUSING LOCALIZED FLOODING AND MUDSLIDES. RAINFALL ASSOCIATED
WITH THE TROPICAL CYCLONE DESCRIBED IN SPECIAL FEATURES IS
EXPECTED TO CONTINUE BEYOND MONDAY.

ATLANTIC OCEAN...

THE HIGHLIGHT ON THE BASIN IS ON THE SW N ATLC WHERE TROPICAL
CYCLOGENESIS OCCURRED EARLIER TODAY. A MIDDLE TO LOWER LEVEL
CYCLONE ANCHORED NEAR THE INAGUA ISLANDS IS ASSOCIATED WITH
TROPICAL DEPRESSION. SEE THE SPECIAL FEATURES SECTION.
OTHERWISE...BESIDES THE TROPICAL WAVES...SURFACE RIDGING AND FAIR
WEATHER DOMINATE ELSEWHERE.

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

$$
NR


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