[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200607
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON JUL 20 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
WWWW UTC.

...TROPICAL WAVES...
TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC EXTENDS ALONG 41W/42W
FROM 5N-17N MOVING W NEAR 20 KT OVER THE PAST 24 HOURS. WAVE
COINCIDES WITH A 700 MB TROUGH BETWEEN 38W-45W. THE TOTAL
PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN AN
SURGE OF MODERATE TO 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 W TROPICAL ATLC EXTENDS ALONG 53W/54W FROM
7N-22N MOVING W 15-20 KT OVER THE PAST 24 HOURS. WAVE COINCIDES
WITH A LOW AMPLITUDE 700 MB TROUGH BETWEEN 51W-55W S OF 14N. THE
TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED
WITHIN AN SURGE OF DEEP MOISTURE THAT EXTENDS N OF 26N. 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. HOWEVER S OF THE AEROSOLS OR
SAHARAN DUST IS A NARROW BAND OF CLUSTERS OF SCATTERED MODERATE
TO ISOLATED STRONG CONVECTION ALONG A LINE FROM 9N48W TO 11N54W.

TROPICAL WAVE IS MOVING OVER THE LESSER ANTILLES INTO THE E
CARIBBEAN EXTENDING ALONG 60W-61W FROM 9N-20N MOVING W NEAR 15
KT OVER THE PAST 24 HOURS. WAVE COINCIDES WITH A 700 MB TROUGH
THAT COVERS THE FAR E CARIBBEAN BETWEEN 60W-65W AND EXTENDS INTO
THE CENTRAL ATLC. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE
WAVE IS EMBEDDED WITHIN AN AREA OF MODERATELY DRY AIR. 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 EXTENDS ACROSS AFRICA INTO THE E
TROPICAL ATLC NEAR 11N15W ALONG 8N21W TO 8N28W WHERE THE ITCZ
BEGINS AND CONTINUES ALONG 9N33W TO E OF THE EASTERN MOST
TROPICAL WAVE NEAR 9N39W THEN RESUMES W OF THE WAVE NEAR 9N43W
TO SOUTH AMERICA NEAR 5N53W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 6N-10N BETWEEN 23W-28W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE COVERS THE N GULF AND INTO THE W ATLC ANCHORED
OVER N LOUISIANA WHILE AN INVERTED UPPER TROUGH EXTENDS FROM THE
W CARIBBEAN GIVING THE S GULF E TO SE FLOW ALOFT. THE UPPER
RIDGE IS ADVECTING UPPER MOISTURE INTO THE NE GULF BRINGING WITH
IT SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF
27N E OF 90W. THE DIURNAL SURFACE TROUGH OVER THE W COAST OF THE
YUCATAN PENINSULA IS GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 20N E OF 93W. THE REMAINDER OF THE GULF IS
DOMINATED BY A SURFACE RIDGE THAT EXTENDS FROM THE W ATLC ACROSS
S FLORIDA TO SE TEXAS WITH A 1018 MB HIGH NEAR 24N85W. SURFACE
RIDGE WILL SHIFT TO THE E GULF MON THEN CHANGE LITTLE THROUGH
THE WEEK.

CARIBBEAN SEA...
AN INVERTED UPPER TROUGH EXTENDS FROM GUATEMALA INTO THE GULF OF
HONDURAS TO E CUBA COVERING THE W CARIBBEAN W OF 78W. AN UPPER
RIDGE ANCHORED IN THE TROPICAL ATLC EXTENDS AN UPPER RIDGE AXIS
ACROSS THE LESSER ANTILLES NEAR MARTINIQUE TO 13N78W. THE
SOUTHERLY FLOW ALOFT ACROSS THE CARIBBEAN IS ADVECTING UPPER
MOISTURE OVER THE S CARIBBEAN BRINGING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS S OF LINE FROM COLOMBIA NEAR 11N74W TO
NICARAGUA NEAR 13N84W. AFTERNOON/EVENING SHOWERS/THUNDERSTORMS
THAT DEVELOPED OVER CUBA HAVE DIMINISH TO SOME ISOLATED SHOWERS
AND POSSIBLE ISOLATED THUNDERSTORMS FROM 19N-21N BETWEEN 76W-
79W. ISOLATED SHOWERS REMAIN ACROSS PORTIONS OF HISPANIOLA. THIS
IS LEAVING THE REMAINDER OF THE CARIBBEAN WITH MOSTLY CLEAR
SKIES TONIGHT. ATLC SURFACE RIDGE WILL MAINTAIN FRESH TO
OCCASIONALLY STRONG TRADE WINDS ACROSS THE S/CENTRAL CARIBBEAN
THROUGH THE WEEK. TROPICAL WAVE OVER THE LESSER ANTILLES WILL
MOVE ACROSS THE E CARIBBEAN THROUGH MON NIGHT THEN ACROSS THE
CENTRAL CARIBBEAN TUE THROUGH WED NIGHT AND ACROSS THE W
CARIBBEAN THU THROUGH FRI NIGHT. THE NEXT TROPICAL WAVE WILL
ENTER THE E CARIBBEAN EARLY TUE THROUGH WED NIGHT THEN THE
CENTRAL CARIBBEAN THU AND THU NIGHT AND THE W CARIBBEAN FRI AND
FRI NIGHT. THE THIRD TROPICAL WAVE WILL MOVE INTO THE E
CARIBBEAN THU THROUGH FRI.

...HISPANIOLA...
CURRENTLY...ISOLATED SHOWERS REMAIN ACROSS THE SW PORTION OF THE
ISLAND TONIGHT. AN UPPER TROUGH OVER THE CENTRAL ATLC DIPS S
OVER THE N PORTION OF THE ISLAND. THIS UPPER TROUGH WILL
ENCOMPASS THE ISLAND BY MON NIGHT AND WILL PERSIST THROUGH THU.
MOISTURE WILL INCREASE LATE MON AHEAD OF A SERIES OF TROPICAL
WAVES THAT MOVE ACROSS THE ISLAND TUE THROUGH THE END OF THE
WEEK. THIS WILL INCREASE THE CHANCE OF SHOWERS AND POSSIBLE
THUNDERSTORMS STARTING TUE AFTERNOON.

ATLANTIC OCEAN...
AN UPPER RIDGE COVERS THE W ATLC N OF 24N W OF 70W. AN UPPER LOW
IS IN THE N/CENTRAL ATLC NEAR 29N55W EXTENDING AN UPPER TROUGH
SW ALONG 25N65W TO OVER THE N PORTION OS HISPANIOLA. AN UPPER
RIDGE IS TO THE S ANCHORED NEAR 15N53W COVERING THE TROPICAL
ATLC. BETWEEN THESE UPPER FEATURES IS AN AREA OF DIFFLUNCE ALOFT
THAT IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
WITHIN 75 NM OF LINE FROM 27N47W TO 23N55W. THE ATLC BASIN IS
DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH NEAR
29N45W WITH A RIDGE AXIS EXTENDING THROUGH A 1020 MB HIGH NEAR
27N72W INTO THE GULF OF MEXICO OVER S FLORIDA. SURFACE RIDGE
WILL SHIFT SLIGHTLY S TUE NIGHT THE CHANGE LITTLE THROUGH THE REST
OF THE WEEK. THE N PORTION OF THE TROPICAL WAVE ALONG 53W/54W
WILL MOVE ACROSS THE SW ATLC MON THROUGH WED.

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

$$
PAW
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