Tropical Weather Discussion
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000
AXNT20 KNHC 290001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUL 28 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...
GALE WARNING...
A GALE WARNING WILL GO INTO EFFECT OVERNIGHT TONIGHT AND END THU
NIGHT FOR THE AREA FROM 11N-14N BETWEEN 74W-78W IN THE SW
CARIBBEAN. THESE GALE FORCE WINDS WILL BE THE RESULT OF A STRONG
PRESSURE GRADIENT BETWEEN W ATLC HIGH PRESSURE AND LOWER
PRESSURE OVER THE SW CARIBBEAN AND 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 31W/32W FROM
11N-20N MOVING W 15-20 KT OVER THE PAST 24 HOURS. THE TOTAL
PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN A
LOW AMPLITUDE SURGE OF DEEP MOISTURE. THE NOAA/NESDIS AEROSOL
PRODUCT AND THE LAST VISIBLE SATELLITE IMAGERY INDICATES THAT
THE WAVE REMAINS WITHIN A PLUMB OF AEROSOLS OR SAHARAN DUST
LIMITING ANY ASSOCIATED CONVECTION.

TROPICAL WAVE IN THE W TROPICAL ATLC EXTENDS ALONG 51W/52W FROM
9N-19N 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. THE NOAA/NESDIS AEROSOL PRODUCT AND
THE LAST 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 CENTRAL CARIBBEAN EXTENDS ALONG 74W/75W S
OF 18N TO OVER SOUTH AMERICA MOVING W 20-25 KT OVER THE PAST 24
HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS
EMBEDDED WITHIN A WEAK SURGE OF MODERATE MOISTURE. THE
NOAA/NESDIS AEROSOL PRODUCT AND THE VISIBLE SATELLITE IMAGERY
INDICATES THAT THE WAVE REMAINS WITHIN A PLUMB OF AEROSOLS OR
SAHARAN DUST LIMITING ANY ASSOCIATED CONVECTION.

TROPICAL WAVE IN THE W CARIBBEAN EXTENDS ALONG 88W FROM S OF 19N
TO OVER CENTRAL AMERICA MOVING W-SW 15-20 KT OVER THE PAST 24
HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS
EMBEDDED WITHIN A EDGE OF SURGE OF MODERATE TO DEEP MOISTURE.
WAVE IS ALONG THE COAST OF THE YUCATAN PENINSULA WITH ANY
ACTIVITY INLAND OVER THE YUCATAN.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E
TROPICAL ATLC NEAR 16N17W ALONG 10N32W TO 11N43W WHERE THE ITCZ
BEGINS AND CONTINUES TO E OF THE TROPICAL WAVE NEAR 10N50W THEN
RESUMES W OF THE WAVE NEAR 9N53W TO SOUTH AMERICA NEAR 7N58W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 7N TO THE
MONSOON TROUGH AND WITHIN 120 NM N OF THE MONSOON TROUGH BETWEEN
18W-30W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE COVERS THE GULF OF MEXICO AND THE E CONUS
ANCHORED OVER THE LOWER MISSISSIPPI VALLEY. A 1012 MB LOW IS
OVER THE FLORIDA PENINSULA NEAR GAINSVILLE WITH A SURFACE TROUGH
EXTENDING W ALONG 28N86W TO 29N88W WITH A SECOND SURFACE TROUGH
EXTENDING E INTO THE W ATLC. SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS ARE OVER THE NE GULF N OF 26N TO THE
SURFACE TROUGH E OF 87W TO ACROSS FLORIDA. A WEAK SURFACE RIDGE
EXTENDS FROM THE W ATLC THROUGH THE STRAITS OF FLORIDA TO
LOUISIANA WITH A 1018 MB HIGH NEAR 25N84W. AN UPPER LOW OVER THE
NW CARIBBEAN IS GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS INLAND AND ALONG THE IMMEDIATE COAST OF CUBA W OF
82W AND ACROSS THE YUCATAN CHANNEL TO NE YUCATAN PENINSULA. THIS
IS LEAVING THE REMAINDER OF THE GULF WITH CLEAR SKIES THIS
EVENING. LOW PRESSURE OVER FLORIDA WILL MOVE INTO THE W ATLC
OVERNIGHT. THE SURFACE RIDGE WILL PERSIST THROUGH THU.

CARIBBEAN SEA...
AN UPPER LOW IS CENTERED OVER THE CAYMAN ISLANDS COVERING THE
NW CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
INLAND AND ALONG THE IMMEDIATE COAST OF CUBA W OF 83W AND ACROSS
THE YUCATAN CHANNEL N OF 21N. A SECOND UPPER LOW IS CENTERED
OVER THE VIRGIN ISLANDS COVERING THE E CARIBBEAN E OF 68W.
AFTERNOON SHOWERS/THUNDERSTORMS HAVE DEVELOPED INLAND OVER
JAMAICA BUT ARE BEGINNING TO DISSIPATE. THE NOAA/NESDIS AEROSOL
PRODUCT AND THE VISIBLE SATELLITE IMAGERY INDICATES THE
CARIBBEAN IS COVERED A PLUMB OF AEROSOLS OR SAHARAN DUST. THIS
IS LEAVING THE REMAINDER OF THE CARIBBEAN WITH MOSTLY CLEAR
SKIES THIS EVENING. W ATLC SURFACE RIDGE WILL MAINTAIN NEAR GALE
TRADE WINDS THROUGH THU INCREASING GALE FORCE OVERNIGHT TONIGHT
THROUGH THU NIGHT ALONG THE COAST OF COLOMBIA. W CARIBBEAN
TROPICAL WAVE WILL MOVE OVER THE YUCATAN TONIGHT. E CARIBBEAN
TROPICAL WAVE CONTINUE W MOVING ACROSS THE W CARIBBEAN WED AND
THU. A THIRD TROPICAL WAVE WILL ENTER THE E CARIBBEAN ON WED
NIGHT AND THE CENTRAL CARIBBEAN BY THU NIGHT.

...HISPANIOLA...
SKIES REMAIN CLEAR ACROSS THE ISLAND THIS EVENING. THE UPPER LOW
OVER THE VIRGIN ISLANDS WILL SHIFT W TO OVER HISPANIOLA WED
NIGHT THEN PERSIST THROUGH THU. MOISTURE WILL INCREASE AGAIN THU
NIGHT AHEAD OF THE NEXT TROPICAL WAVE. HOWEVER DAYTIME HEATING
COULD STILL PRODUCE A CHANCE OF OF ISOLATED SHOWERS AND POSSIBLE
THUNDERSTORMS DURING THE AFTERNOON/EVENINGS HOURS THROUGH THU.

ATLANTIC OCEAN...
THE UPPER RIDGE OVER THE E CONUS AND GULF OF MEXICO EXTENDS OVER
THE FAR W ATLC N OF 26N W OF 76W WITH A BROAD UPPER TROUGH JUST
N OF THE DISCUSSION AREA SUPPORTING A STATIONARY FRONT THAT
EXTENDS ALONG 32N BETWEEN BERMUDA AND A WEAK 1014 MB LOW NEAR
32N76W THEN TO 31N80W. A SURFACE TROUGH EXTENDS FROM THE 1012 MB
LOW OVER FLORIDA INTO THE W ATLC NEAR SAINT AUGUSTINE TO 31N79W.
THIS IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF
A LINE FROM 26N77W 29N70W TO 32N62W. SCATTERED TO NUMEROUS
SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 27N TO THE SURFACE
TROUGH AND W OF 79W TO INLAND OVER FLORIDA. A SURFACE RIDGE
COVERS THE E ATLC ANCHORED BY A 1026 MB HIGH ABOUT 250 NM S-SW
OF THE AZORES WITH A NARROWING RIDGE AXIS S OF THE W ATLC
FRONTAL SYSTEM AND EXTENDS THROUGH 32N38W TO A 1020 MB HIGH NEAR
26N60W THEN THROUGH THE STRAITS OF FLORIDA INTO THE GULF OF
MEXICO. THIS NARROW RIDGE AXIS WILL SHIFT SLIGHTLY S TONIGHT AND
WED. THE LOW OVER FLORIDA WILL MOVE INTO THE W ATLC TONIGHT THEN
SHIFT N OF THE AREA BY THU.

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

$$
PAW


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