Tropical Weather Discussion
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000
AXNT20 KNHC 040537
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT JUL 04 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...

...GALE IN THE CARIBBEAN...
A GALE WARNING IS IN EFFECT FOR THE SW CARIBBEAN FROM 11N-13N
BETWEEN 73W-77W THROUGH SUN. THESE WINDS ARE GENERATED BY A
TIGHT PRESSURE GRADIENT BETWEEN THE STRONG SURFACE RIDGE OVER
THE ATLC AND THE LOWER PRESSURE OVER SOUTH AMERICA. SEE LATEST
NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02
KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IN THE E TROPICAL ATLC EXTENDS ALONG 25W/26W FROM
6N-16N MOVING W AT 5-10 KT OVER THE PAST 24 HOURS. THE TOTAL
PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN AN
SURGE OF MODERATE MOISTURE. NO ASSOCIATED DEEP CONVECTION.

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC EXTENDS ALONG 42W
FROM 5N-12N MOVING NEAR 5 KT OVER THE PAST 24 HOURS. THE TOTAL
PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN LOW
AMPLITUDE SURGE OF DEEP MOISTURE. WAVE IS INTERACTING WITH AN
UPPER LOW AND GENERATING SCATTERED MODERATE/ISOLATED STRONG
CONVECTION FROM 8N-10N BETWEEN 36W-42W.

TROPICAL WAVE IN THE E CARIBBEAN EXTENDS ALONG 69W/70W FROM 18N
TO THE COAST OF VENEZUELA MOVING W NEAR 20 KT OVER THE PAST 24
HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS
EMBEDDED WITHIN A SURGE OF MODERATE MOISTURE. NO ASSOCIATED DEEP
CONVECTION.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC
NEAR 12N16W TO E OF THE TROPICAL WAVE NEAR 9N21W. THE ITCZ
BEGINS W OF THE WAVE NEAR 9N28W TO E OF THE NEXT TROPICAL WAVE
NEAR 7N40W THEN RESUMES W OF THIS WAVE NEAR 7N44W INTO SOUTH
AMERICA NEAR 6N54W. NO SIGNIFICANT CONVECTION.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH DOMINATES THE GULF TONIGHT EXTENDING FROM NEAR
TAMPA BAY FLORIDA THROUGH AN UPPER LOW NEAR 22N89W TO VERACRUZ
MEXICO. THIS IS GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 24N-28N E OF 84W TO INLAND OVER THE FLORIDA
PENINSULA AND IN THE W BAY OF CAMPECHE WITHIN 75 NM ALONG THE
COAST OF MEXICO FROM TAMPICO TO JUST E OF COATZACOALCOS. THE
DIURNAL SURFACE TROUGH IS OFF THE W COAST OF THE YUCATAN
PENINSULA GENERATING ISOLATED SHOWERS FROM 20N-23N BETWEEN 89W-
92W. SURFACE RIDGE EXTENDS FROM THE ATLC ACROSS CENTRAL FLORIDA
TO TEXAS WITH A 1019 MB HIGH NEAR 28N84W. THE SURFACE RIDGE WILL
PERSIST ALONG 28N/29N THROUGH TUE.

CARIBBEAN SEA...
AN UPPER TROUGH OVER THE GULF OF MEXICO IS DRAWING UPPER
MOISTURE ACROSS THE FAR NW CARIBBEAN AND COUPLED WITH THE
EASTERLY SURFACE FLOW IS GENERATING A LINE OF SCATTERED SHOWERS
AND POSSIBLE ISOLATED THUNDERSTORMS BETWEEN 19N-20N W OF 85W TO
INLAND OVER THE NE YUCATAN PENINSULA. NOAA/NESDIS AEROSOL
PRODUCT AND THE LAST VISIBLE SATELLITE IMAGERY INDICATES THAT A
PLUMB OF AEROSOLS OR SAHARAN DUST COVERS THE CARIBBEAN LIMITING
SHOWERS AND DEEP CONVECTION. HOWEVER THE EASTERLY TRADE WINDS
ARE ALLOWING ISOLATED LOW LEVEL SHOWERS TO FORM OVER THE E
CARIBBEAN E OF 70W LEAVING THE MOST OF THE CARIBBEAN WITH FAIR
BUT HAZY SKIES TONIGHT. A PERSISTENT STRONG ATLC SURFACE RIDGE
WILL MAINTAIN STRONG TRADE WINDS ACROSS THE CARIBBEAN WITH
MINIMAL GALE FORCE WINDS ALONG THE NW COAST OF COLOMBIA THROUGH
SUN. WEAK TROPICAL WAVE IN THE CENTRAL CARIBBEAN WILL MOVE W
ACROSS THE BASIN THROUGH TUE.

...HISPANIOLA...
SKIES REMAIN CLEAR ACROSS THE ISLAND TONIGHT. ALTHOUGH AN UPPER
LOW N OF THE ISLAND EXTENDS AN UPPER TROUGH TO OVER THE
ISLAND...THE STRONG SUBSIDENCE AND AEROSOLS OR SAHARAN DUST IS
LIMITING CONVECTION TO POSSIBLE ISOLATED SHOWERS. SHOWERS COULD
INCREASE SAT AS THE CENTRAL CARIBBEAN TROPICAL WAVE MOVES W JUST
S OF THE ISLAND. OTHERWISE EXPECT ONLY POSSIBLE ISOLATED
AFTERNOON SHOWERS THROUGH THE FIRST OF NEXT WEEK.

ATLANTIC OCEAN...
AN UPPER RIDGE IS ANCHORED NEAR 26N78W COVERING THE W ATLC W OF
75W AND IS PROVIDING A DIFFLUENT ENVIRONMENT TO THE W TO
GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 24N-27N W
OF 78W TO INLAND OVER THE FLORIDA PENINSULA. THE UPPER LOW N OF
HISPANIOLA IS CENTERED NEAR 26N70W AND IS GENERATING ISOLATED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 24N-29N BETWEEN
65W-72W. A PAIR OF WEAK SURFACE TROUGHS ARE IN THE CENTRAL
ATLC...ONE EXTENDING FROM 27N47W TO 23N46W AND THE SECOND FROM
30N56W TO 25N54W WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS WITHIN 45 NM OF LINE FROM 25N51W TO 28N56W. THE
REMAINDER OF THE ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED
BY A 1030 MB HIGH N OF THE AREA NEAR 34N45W AND EXTENDING A
RIDGE AXIS THROUGH 32N60W TO ACROSS CENTRAL FLORIDA AND INTO THE
GULF OF MEXICO. NOAA/NESDIS AEROSOL PRODUCT AND THE LAST VISIBLE
SATELLITE IMAGERY INDICATES THAT A LARGE DENSE PLUMB OF AEROSOLS
OR SAHARAN DUST COVERS THE TROPICS N OF THE ITCZ TO 24N/25N INTO
THE CARIBBEAN. THE SURFACE RIDGE WILL PERSIST THROUGH THE TUE.

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

$$
PAW



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