Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 231040
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU JUL 23 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IN THE TROPICAL ATLC EXTENDS ALONG 35W FROM 9N-17N
MOVING W 15-20 KT OVER THE PAST 24 HOURS. THE TOTAL PRECIPITABLE
WATER IMAGERY SHOWS THE WAVE IS N OF ANY DEEP MOISTURE. THE
NOAA/NESDIS AEROSOL PRODUCT AND THE FIRST VISIBLE SATELLITE
IMAGERY INDICATES THAT THE WAVE REMAINS EMBEDDED WITHIN A PLUMB
OF AEROSOLS OR SAHARAN DUST LIMITING ANY ASSOCIATED CONVECTION.

TROPICAL WAVE IN THE E CARIBBEAN EXTENDS ALONG 70W/71W S OF 20N
TO INLAND OVER SOUTH AMERICA MOVING W 15-20 KT OVER THE PAST 24
HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS
EMBEDDED WITHIN AN SURGE OF MODERATE TO DEEP MOISTURE. SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS DOT THE AREA S OF
15N TO OVER SOUTH AMERICA BETWEEN 67W-72W.

TROPICAL WAVE IN THE W CARIBBEAN EXTENDS ALONG 84W S OF 20N TO
INLAND OVER CENTRAL AMERICA MOVING W NEAR 25 KT OVER THE PAST 24
HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS
EMBEDDED WITHIN AN SURGE OF DEEP MOISTURE. SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS DOT THE AREA S OF 16N W OF 82W
TO INLAND OVER CENTRAL AMERICA.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E
TROPICAL ATLC NEAR 13N17W ALONG 10N21W TO 9N32W WHERE THE ITCZ
BEGINS AND CONTINUES ALONG 7N44W TO SOUTH AMERICA NEAR 6N54W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 6N-9N BETWEEN 20W-46W AND FROM 5N-8N BETWEEN 46W-58W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 200 NM
ALONG THE COAST OF W AFRICA FROM 6N-11N.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE ANCHORED IN THE W ATLC COVERS THE NE GULF WHILE
AN UPPER LOW CENTERED IN THE S GULF NEAR 24N91W COVERS THE
REMAINDER OF THE GULF. A WEAK SURFACE RIDGE EXTENDS FROM THE W
ATLC THROUGH THE STRAITS OF FLORIDA TO NE TEXAS WITH A 1018 MB
HIGH NEAR 25N86W. THE WEAK DIURNAL SURFACE TROUGH EXTENDS OVER
THE CENTRAL BAY OF CAMPECHE GENERATING ISOLATED SHOWERS S OF 20N
BETWEEN 93W-96W. ISOLATED SHOWERS ARE POSSIBLE ACROSS THE NE
GULF N OF 28N E OF 89W LEAVING THE REMAINDER OF THE GULF WITH
CLEAR SKIES AGAIN THIS MORNING. SURFACE RIDGE WILL PERSIST
THROUGH SAT.

CARIBBEAN SEA...
A CUTOFF UPPER LOW IS OVER HISPANIOLA WITH AN UPPER TROUGH
COVERING THE CARIBBEAN BETWEEN 68W-80W. THIS UPPER TROUGH
COUPLED WITH THE TROPICAL WAVE IS GENERATING ISOLATED SHOWERS
INLAND AND ALONG THE IMMEDIATE COAST OF HISPANIOLA. AN UPPER
RIDGE ANCHORED OVER CENTRAL AMERICA EXTENDS OVER THE SW
CARIBBEAN WHILE THE UPPER RIDGE ANCHORED IN THE TROPICAL ATLC
EXTENDS ACROSS THE REMAINDER OF THE E CARIBBEAN. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE SW CARIBBEAN S OF
12N BETWEEN 73W-82W LEAVING THE REMAINDER OF THE CARIBBEAN WITH
MOSTLY CLEAR SKIES THIS MORNING. W ATLC SURFACE RIDGE WILL
MAINTAIN MODERATE TO FRESH TRADE WINDS WITH STRONG TO OCCASIONAL
NEAR GALE CONDITIONS OCCURRING OFF THE COAST OF COLOMBIA THROUGH
SAT. THE TROPICAL WAVES WILL CONTINUE TO MOVE ACROSS THE
CARIBBEAN THROUGH SAT.

...HISPANIOLA...
ISOLATED SHOWERS REMAIN INLAND AND ALONG THE IMMEDIATE COAST OF
THE ISLAND THIS MORNING. THIS ACTIVITY IS DUE TO THE CUTOFF
UPPER LOW OVER THE ISLAND AND THE TROPICAL WAVE MOVING ACROSS
THE DOMINICAN REPUBLIC. THIS UPPER LOW WILL PERSIST THROUGH
TODAY BEFORE SHIFTING W FRI AND SAT. MOISTURE ASSOCIATED WITH
THE TROPICAL WAVE WILL REMAIN ACROSS THE ISLAND THROUGH EARLY
FRI GIVING THE ISLAND SHOWERS AND POSSIBLE THUNDERSTORMS.
LINGERING MOISTURE COUPLED WITH DAYTIME HEATING COULD STILL
PRODUCE CHANCE OF SHOWERS AND POSSIBLE THUNDERSTORMS DURING THE
AFTERNOON/EVENINGS HOURS FRI AND SAT.

ATLANTIC OCEAN...
AN UPPER RIDGE IS ANCHORED IN THE W ATLC NEAR 28N79W COVERING
THE W ATLC W OF 70W. AN ELONGATED UPPER LOW IS CENTERED IN THE
CENTRAL ATLC NEAR 25N47W WHILE A SECOND CUTOFF UPPER LOW IS OVER
HISPANIOLA GIVING THE REMAINDER OF THE W ATLC AND CENTRAL ATLC
BROAD TROUGHING. THE CENTRAL ATLC UPPER LOW IS SUPPORTING A
SURFACE TROUGH THAT EXTENDS FROM 29N42W TO 24N42W GENERATING
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS 24N-29N
BETWEEN THE SURFACE TROUGH AND 46W. THE BROAD TROUGHING IS
GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
FROM 25N-30N BETWEEN 50W-65W. THE ATLC BASIN IS DOMINATED BY A
SURFACE RIDGE ANCHORED BY A 1025 MB HIGH N OF THE DISCUSSION
AREA NEAR 32N34W AND EXTENDING A RIDGE AXIS THROUGH A 1023 MB
HIGH NEAR 26N53W THEN W THROUGH THE STRAITS OF FLORIDA AND INTO
THE GULF OF MEXICO. SURFACE RIDGE WILL RETREAT EASTWARD AND
WEAKEN FRI NIGHT INTO SAT AS A WEAK LOW MOVES OFF THE SE U.S.
COAST.

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

$$
PAW



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