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AXNT20 KNHC 292355
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUL 29 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 AFTERNOON FOR THE AREA FROM 11N-14N BETWEEN 74W-78W IN THE SW CARIBBEAN. THESE GALE FORCE WINDS ARE 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 29W FROM 8N- 17N MOVING W-SW 10-15 KT OVER THE PAST 12 HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN A 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 CENTRAL TROPICAL ATLC EXTENDS ALONG 44W FROM 9N-16N MOVING W-SW NEAR 30 KT OVER THE PAST 24 HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN A LOW AMPLITUDE SURGE OF MODERATE TO 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 IS IN THE W TROPICAL ATLC IS MOVING INTO THE E CARIBBEAN ALONG 61W FROM 9N-18N IS MOVING W NEAR 20 KT OVER THE PAST 24 HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS ALONG THE LEADING EDGE OF A SURGE OF MODERATE TO DEEP MOISTURE. THE NOAA/NESDIS AEROSOL PRODUCT AND THE 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 W CARIBBEAN EXTENDS ALONG 84W S OF 20N TO OVER CENTRAL AMERICA 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 VISIBLE SATELLITE IMAGERY INDICATES THAT THE WAVE IS EMBEDDED WITHIN A PLUMB OF AEROSOLS OR SAHARAN DUST LIMITING ANY ASSOCIATED CONVECTION. THE ACTIVITY W OF THE WAVE IS ASSOCIATED WITH UPPER LEVEL FEATURES.


...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 20N16W ALONG 16N20W TO A 1010 MB LOW NEAR 12N23W THEN TO E OF THE EASTERN MOST TROPICAL WAVE NEAR 11N27W THEN RESUMES W OF THE WAVE NEAR 10N30W ALONG 9N34W TO 10N39W WHERE THE ITCZ BEGINS AND CONTINUES TO E OF THE NEXT TROPICAL WAVE NEAR 11N43W THEN RESUMES W OF THE WAVE NEAR 11N46W TO E OF THE NEXT WAVE NEAR 11N59W. SCATTERED MODERATE/STRONG CONVECTION IS ASSOCIATED WITH THE 1010 MB LOW WITHIN 90 NM OF THE CENTER OVER THE S QUADRANT AND WITHIN 60 NM OF 12N BETWEEN 22W-28W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 90 NM ALONG THE COAST OF AFRICA BETWEEN 11N-14N.


...DISCUSSION...

GULF OF MEXICO... A BROAD UPPER RIDGE REMAINS OVER THE GULF OF MEXICO AND THE E CONUS INTO THE W ATLC ANCHORED OVER THE LOWER MISSISSIPPI VALLEY AND THE MOUNTAINS OF NORTH CAROLINA. A 1013 MB LOW IS IN THE W ATLC WITH A SURFACE TROUGH EXTENDING ACROSS FLORIDA BETWEEN VERO BEACH AND FORT MYERS THEN TO 26N86W IN THE GULF WATERS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 25N-28N E OF 88W TO OVER FLORIDA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE MOVING S INTO THE NE GULF N OF LINE FROM TAMPA BAY FLORIDA TO 29N86W TO THE LOUISIANA COAST NEAR SLIDELL. A WEAK SURFACE RIDGE EXTENDS FROM THE W ATLC OVER S FLORIDA/STRAITS OF FLORIDA TO A 1018 MB HIGH NEAR 26N92W TO OVER THE SE CONUS NEAR THE LOUISIANA/TEXAS BORDER. THE UPPER TROUGH OVER THE NW CARIBBEAN IS GENERATING SCATTERED SHOWERS/THUNDERSTORMS INLAND AND ALONG THE IMMEDIATE COAST OF CUBA W OF 81W. ISOLATED SHOWERS/ THUNDERSTORMS ARE POSSIBLE WITHIN 120 NM OF LINE FROM 23N86W TO 28N92W LEAVING THE REMAINDER OF THE GULF WITH CLEAR SKIES THIS EVENING. THE SURFACE RIDGE WILL PERSIST THROUGH THU THEN SHIFT S ON FRI AS A WEAK COLD FRONT MOVES INTO THE N/CENTRAL GULF.

CARIBBEAN SEA... AN UPPER TROUGH EXTENDS FROM AN UPPER LOW IN THE SW ATLC ACROSS HISPANIOLA THEN W ALONG 17N80W TO THE GULF OF HONDURAS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND AND ALONG THE IMMEDIATE COAST OF CUBA W OF 81W AND FROM 18N-20N BETWEEN 84W-87W. A SECOND UPPER TROUGH EXTENDS FROM HISPANIOLA TO THE ABC ISLANDS. AFTERNOON ISOLATED SHOWERS/THUNDERSTORMS HAVE DEVELOPED INLAND OVER PUERTO RICO AND S HAITI. THE NOAA/NESDIS AEROSOL PRODUCT AND THE VISIBLE SATELLITE IMAGERY INDICATES THE CARIBBEAN IS COVERED A PLUMB OF AEROSOLS OR SAHARAN DUST LEAVING THE REMAINDER OF THE CARIBBEAN WITH MOSTLY CLEAR SKIES THIS EVENING. W ATLC SURFACE RIDGE WILL MAINTAIN STRONG TO NEAR GALE TRADE WINDS THROUGH FRI INCREASING TO GALE FORCE OVERNIGHT TONIGHT THROUGH THU AFTERNOON ALONG THE COAST OF COLOMBIA. W CARIBBEAN TROPICAL WAVE WILL MOVE OVER THE YUCATAN PENINSULA THU. TROPICAL WAVE MOVING INTO THE E CARIBBEAN WILL MOVE ACROSS THE E CARIBBEAN THROUGH THU REACHING THE W CARIBBEAN FRI NIGHT.


...HISPANIOLA... SCATTERED SHOWERS/ISOLATED THUNDERSTORMS HAVE DEVELOPED OVER S HAITI THIS EVENING. THE UPPER LOW OVER THE SW ATLC WILL KEEP AN UPPER TROUGH OVER THE ISLAND THROUGH FRI. 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 WITH AN INCREASE CHANCE OF OF SHOWERS AND THUNDERSTORMS ON FRI.

ATLANTIC OCEAN... THE UPPER RIDGE OVER THE E CONUS AND GULF OF MEXICO EXTENDS OVER THE FAR W ATLC W OF 76W. A WEAK 1013 MB LOW IS CENTERED NEAR 31N77W WITH A SURFACE TROUGH EXTENDING OVER FLORIDA INTO THE GULF OF MEXICO NEAR VERO BEACH. THIS IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 200 NM SE OF THE SURFACE TROUGH. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 28N BETWEEN 63W-73W ASSOCIATED WITH A FRONTAL SYSTEM N OF THE DISCUSSION AREA. AN UPPER LOW IS CENTERED IN THE SW ATLC NEAR 21N68W EXTENDING AN UPPER TROUGH AXIS OVER HISPANIOLA AND IS GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 20N-23N BETWEEN 65W-69W. A SURFACE RIDGE COVERS THE E ATLC ANCHORED BY A 1027 MB HIGH ABOUT 350 NM SW OF THE AZORES WITH A NARROWING RIDGE AXIS S OF THE W ATLC FRONTAL SYSTEM AND EXTENDS THROUGH 32N39W ALONG 27N60W THEN ACROSS S FLORIDA/STRAITS OF FLORIDA INTO THE GULF OF MEXICO. THE W ATLC 1013 MB LOW AND SURFACE TROUGH WILL MOVE N OF THE AREA BY THU. THE SURFACE RIDGE WILL DOMINATE THE REMAINDER THE ATLC SHIFTING N AND STRENGTHENING BY FRI.

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

$$ PAW

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