[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211040
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE JUL 21 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 OFF THE COAST OF AFRICA EXTENDS ALONG 19W/20W FROM
5N-14N MOVING W NEAR 10 KT OVER THE PAST 12 HOURS. WAVE
COINCIDES WITH A BROAD 700 MB TROUGH THAT COVERS THE AREA
BETWEEN AFRICA AND THE CAPE VERDE ISLANDS AS DEPICTED BY THE
GLOBAL MODEL. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE
WAVE IS EMBEDDED WITHIN A LOW AMPLITUDE SURGE OF MODERATE
MOISTURE. THE NOAA/NESDIS AEROSOL PRODUCT AND THE FIRST VISIBLE
SATELLITE IMAGERY INDICATES THAT THE WAVE IS EMBEDDED WITHIN A
PLUMB OF AEROSOLS OR SAHARAN DUST LIMITING ANY ASSOCIATED
CONVECTION.

TROPICAL WAVE IN THE W TROPICAL ATLC EXTENDS ALONG 51W/52W FROM
8N-17N MOVING W 20-25 KT OVER THE PAST 24 HOURS. WAVE IS
EMBEDDED WITHIN A 700 MB TROUGH AS DEPICTED BY THE GLOBAL MODEL.
THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED
WITHIN AN SURGE OF DEEP MOISTURE. HOWEVER THE NOAA/NESDIS
AEROSOL PRODUCT AND THE LAST VISIBLE SATELLITE IMAGERY INDICATES
THAT THE WAVE IS ALSO EMBEDDED WITHIN A PLUMB OF AEROSOLS OR
SAHARAN DUST LIMITING ANY ASSOCIATED CONVECTION.

TROPICAL WAVE IN THE E CARIBBEAN EXTENDS ALONG 64W/65W S OF 21N
TO INLAND OVER VENEZUELA MOVING W 20-25 KT OVER THE PAST 24
HOURS. WAVE COINCIDES WITH A LOW AMPLITUDE 700 MB TROUGH S OF
16N AS DEPICTED BY THE GLOBAL MODEL. THE TOTAL PRECIPITABLE
WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN AN SURGE OF DEEP
MOISTURE THAT EXTENDS NE OF THE WAVE. THE NOAA/NESDIS AEROSOL
PRODUCT AND THE LAST VISIBLE SATELLITE IMAGERY INDICATES THAT
THE WAVE IS ALONG THE LEADING EDGE OF A PLUMB OF AEROSOLS OR
SAHARAN DUST. CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS DOT THE CARIBBEAN BETWEEN 62W-68W AND S OF 23N TO
OVER THE VIRGIN ISLANDS AND PUERTO RICO BETWEEN 62W-66W.

TROPICAL WAVE IN THE CENTRAL CARIBBEAN EXTENDS ALONG 72W S OF
17N TO INLAND OVER SOUTH AMERICA MOVING W-SW NEAR 20 KT OVER THE
PAST 24 HOURS. WAVE IS TRAILING THE 700 MB TROUGH THAT COVERS
THE CENTRAL CARIBBEAN AS DEPICTED BY THE GLOBAL MODEL. THE TOTAL
PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN A
LOW AMPLITUDE SURFACE OF MODERATE TO DEEP MOISTURE. THE
NOAA/NESDIS AEROSOL PRODUCT AND THE LAST VISIBLE SATELLITE
IMAGERY INDICATES THAT THE WAVE IS ALSO EMBEDDED WITHIN A
PREVIOUS PLUMB OF AEROSOLS OR SAHARAN DUST AGAIN LIMITING ANY
ASSOCIATED CONVECTION.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS BEGINS W OF THE EASTERN MOST TROPICAL
WAVE NEAR 11N21W AND EXTENDS TO 6N32W WHERE THE ITCZ BEGINS AND
CONTINUES ALONG 5N44W TO 8N58W. CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE WITHIN 90 NM OF LINE FROM 10N15W
TO 7N19W...WITHIN 90 NM EITHER SIDE OF THE MONSOON TROUGH/ITCZ
BETWEEN 25W-36W...WITHIN 60 NM OF 7N BETWEEN 40W-44W...AND
WITHIN 60 NM EITHER SIDE OF THE ITCZ BETWEEN 52W-56W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE REMAINS OVER E TEXAS COVERING THE NW GULF
WHILE A SECOND UPPER RIDGE OVER SOUTH CAROLINA COVERS THE NE
GULF. THE UPPER LOW CENTERED OVER THE NE YUCATAN PENINSULA
COVERS THE S GULF. THE DIURNAL SURFACE TROUGH HAS DISSIPATED BUT
IS STILL GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS S OF 20N BETWEEN 93W-95W. A WEAK SURFACE RIDGE
EXTENDS FROM THE W ATLC TO OVER THE STRAITS OF FLORIDA WITH A
1017 MB HIGH OVER THE W TIP OF CUBA. ISOLATED SHOWERS ARE
POSSIBLE ACROSS THE N GULF N OF 25N LEAVING THE REMAINDER OF THE
GULF WITH FAIR WEATHER THIS MORNING. SURFACE RIDGE WILL CHANGE
LITTLE THROUGH THU.

CARIBBEAN SEA...
AN UPPER LOW IS CENTERED OVER NE YUCATAN PENINSULA JUST W OF
CANCUN COVERING THE NW CARIBBEAN AND INTO THE GULF OF MEXICO. AN
UPPER RIDGE ANCHORED IN THE TROPICAL ATLC EXTENDS AN UPPER RIDGE
AXIS ACROSS THE WINDWARD ISLANDS NEAR GRENADA ALONG 14N72W TO
14N84W. AN UPPER TROUGH OVER THE W/CENTRAL ATLC EXTENDS S OVER
THE ISLANDS BETWEEN THE VIRGIN ISLANDS AND HISPANIOLA. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE SW CARIBBEAN S OF
10N BETWEEN 75W-79W. THE ACTIVITY OVER THE E CARIBBEAN E OF 68W
IS ASSOCIATED WITH THE TROPICAL WAVE. THIS IS LEAVING THE
REMAINDER OF THE CARIBBEAN WITH MOSTLY CLEAR SKIES THIS MORNING.
W ATLC SURFACE RIDGE WILL MAINTAIN MODERATE TO FRESH TRADE WINDS
THROUGH THU. CENTRAL CARIBBEAN TROPICAL WAVE WILL MOVE INTO THE
W CARIBBEAN TONIGHT AND MOVE OVER CENTRAL AMERICA WED THROUGH
THU. THE E CARIBBEAN TROPICAL WAVE WILL MOVE INTO THE CENTRAL
CARIBBEAN WED AND THE W CARIBBEAN THU. THE THIRD TROPICAL WAVE
WILL MOVE INTO THE E CARIBBEAN WED AFTERNOON AND THE CENTRAL
CARIBBEAN THU.

...HISPANIOLA...
CURRENTLY...SKIES HAVE CLEARED ACROSS THE ISLAND THIS MORNING. AN
UPPER TROUGH OVER THE W/CENTRAL ATLC COVERS THE ISLANDS FROM THE
VIRGIN ISLANDS TO HISPANIOLA AND WILL PERSIST THROUGH MID WEEK.
MOISTURE WILL INCREASE THIS AFTERNOON AHEAD OF A TROPICAL WAVE
THAT MOVE ACROSS THE ISLAND TONIGHT WITH A SECOND TROPICAL WAVE
MOVING ACROSS THE ISLAND THU. THIS WILL INCREASE THE CHANCE OF
SHOWERS AND POSSIBLE THUNDERSTORMS STARTING THIS AFTERNOON.

ATLANTIC OCEAN...
AN UPPER RIDGE COVERS THE W ATLC N OF 27N W OF 70W. AN UPPER
TROUGH EXTENDS FROM AN UPPER LOW IN THE N/CENTRAL ATLC NEAR
32N43W ALONG 26N56W TO A SECOND WEAKER UPPER LOW NEAR 23N65W
THEN CONTINUING TO 23N72W. AN UPPER RIDGE IS TO THE S ANCHORED
NEAR 13N52W COVERING THE TROPICAL ATLC. BETWEEN THESE UPPER
FEATURES IS A MID LEVEL LOW CENTERED NEAR 25N47W GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 23N-28N BETWEEN
45W-56W. THE ACTIVITY N OF THE VIRGIN ISLANDS IS ASSOCIATED WITH
THE E CARIBBEAN TROPICAL WAVE. THE ATLC BASIN IS DOMINATED BY A
SURFACE RIDGE ANCHORED BY A 1023 MB HIGH NEAR 29N47W WITH A
RIDGE AXIS EXTENDING THROUGH 28N62W TO THE STRAITS OF FLORIDA.
SURFACE RIDGE WILL CHANGE LITTLE THROUGH THU. THE N PORTION OF
THE E CARIBBEAN TROPICAL WAVE WILL MOVE ACROSS THE SW ATLC
THROUGH THU.

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

$$
PAW
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