000
AXNT20 KNHC 081041
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT AUG 08 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1015 UTC.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS ALONG 9N21W JUST W OF THE CAPE VERDE 
ISLANDS TO 18N29W MOVING W NEAR 15 KT. WAVE REMAINS EMBEDDED 
WITH A MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER 
IMAGERY. THERE IS NO DEEP CONVECTION ASSOCIATED WITH THE WAVE 
BUT ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE WAVE 
AXIS FROM 13N-16N. 

TROPICAL WAVE IS ALONG 40W/41W S OF 16N MOVING W NEAR 15 KT. 
WAVE IS MOVING THROUGH AN AREA OF DRY STABLE AIR AND THE 
LOCATION IS BASED ON CONTINUITY WITH NO ASSOCIATED SHOWERS OR 
DEEP CONVECTION. 

TROPICAL WAVE IS ALONG 57W/58W S OF 15N MOVING W NEAR 15 KT. 
WAVE REMAINS IN AN AREA BENEATH AN UPPER RIDGE THUS MASKING THE 
WAVE SIGNATURE AND THE CONVECTION MAY BE ASSOCIATED MORE WITH 
THE ITCZ THAN THE WAVE ITSELF. SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION IS WITHIN 60/75 NM OF LINE FROM 13N54W TO 
11N59W. 

TROPICAL WAVE IS ALONG 75W S OF 19N MOVING W NEAR 15 KT. WAVE IS 
NOW ALONG THE TRAILING EDGE OF A MOISTURE MAXIMUM OBSERVED IN 
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS ARE W OF THE WAVE FROM 14N-16N BETWEEN 76W-79W. 

TROPICAL WAVE IS ALONG 93W/94W S OF 21N MOVING W 15-20 KT. 
WAVE REMAINS WITHIN A BROAD AREA OF DEEP LAYER MOISTURE AS NOTED 
ON TOTAL PRECIPITABLE WATER IMAGERY THAT COVERS THE GULF OF 
MEXICO AND INTO THE E PACIFIC REGION. SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS ARE OVER THE BAY OF CAMPECHE S OF 21N TO OVER 
MEXICO BETWEEN THE WAVE AXIS AND 97W WITH ISOLATED SHOWERS S OF 
24N BETWEEN 89W-93W INCLUDING THE YUCATAN PENINSULA.  

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 13N15W 9N31W 13N50W 10N63W. A 
NEAR STATIONARY SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ 
EXTENDING FROM 15N46W TO 8N51W WITH SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION W OF THE TROUGH AXIS WITHIN 120 NM OF LINE 
FROM 15N49W TO 11N53W. SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION HAS MOVED OFF W AFRICA WITHIN 75/90 NM OF LINE FROM 
12N20W TO THE COAST NEAR 10N14W. SCATTERED CLUSTERS OF SCATTERED 
MODERATE CONVECTION ARE WITHIN 75 NM OF 10N BETWEEN 43W-47W. 

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH EXTENDS ACROSS THE GULF OF MEXICO FROM AN 
UPPER LOW OVER MOBILE ALABAMA THROUGH 25N95W TO A SECOND UPPER 
LOW CENTERED OVER E/CENTRAL MEXICO NEAR 22N99W. A SURFACE TROUGH 
EXTENDS JUST TO THE SE OF THIS UPPER TROUGH FROM NEAR 
JACKSONVILLE FLORIDA ALONG 28N86W TO 25N90W WITH CLUSTERS OF 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 25N-30N BETWEEN 
83W-90W. ISOLATED SHOWERS/THUNDERSTORMS DOT THE REMAINDER OF THE 
W GULF. A BROAD UPPER RIDGE EXTENDS FROM THE OVER THE YUCATAN 
PENINSULA OVER THE REMAINDER OF THE E GULF. 

CARIBBEAN SEA...
AN UPPER RIDGE OVER THE YUCATAN PENINSULA INTO THE E GULF OF 
MEXICO COVERS THE W CARIBBEAN...WITH AN UPPER TROUGH OVER THE 
CENTRAL CARIBBEAN...AND A SECOND UPPER RIDGE OVER THE E 
CARIBBEAN. THE UPPER LEVEL DIFFLUENCE OVER THE W/CENTRAL 
CARIBBEAN IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS 
FROM S OF 12N TO OVER PANAMA BETWEEN 77W-81W AND S OF 17N W OF 
81W TO INLAND OVER CENTRAL AMERICA. THE CARIBBEAN E OF 75W IS 
DOMINATED BY DRY STABLE AIR LIMITING SHOWER ACTIVITY. FRESH TO 
STRONG TRADE WINDS CONTINUE ACROSS MUCH OF THE E AND CENTRAL 
CARIBBEAN. 

ATLANTIC OCEAN...
AN UPPER RIDGE IS OVER THE W ATLC ANCHORED OVER THE N BAHAMA 
ISLANDS WITH A NARROW UPPER TROUGH TO THE E EXTENDING THROUGH 
32N63W THROUGH THE WINDWARD PASSAGE AND OVER THE CENTRAL 
CARIBBEAN. THIS COMBINATION IS PROVIDING UPPER LEVEL DIFFLUENCE 
TO GENERATE CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS 
WITHIN 75/90 NM OF LINE FROM THE BAHAMAS NEAR 24N76W TO BEYOND 
32N68W. A SURFACE TROUGH IS BENEATH THE UPPER RIDGE EXTENDING 
FROM 29N73W TO OVER THE BAHAMAS NEAR 25N77W BUT IS NOT 
GENERATING ANY SIGNIFICANT WEATHER. A LARGE UPPER LOW IS IN THE 
CENTRAL ATLC NEAR 28N46W WITH A SURFACE TROUGH EXTENDING 31N47W 
TO 25N44W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS 
ARE ALONG THE N PERIPHERY OF THE UPPER LOW WITHIN 75 NM OF LINE 
FROM 32N45W TO 27N52W AND ISOLATED SHOWERS WITHIN 90 NM EITHER 
SIDE OF THE SURFACE TROUGH. THE REMAINDER OF THE ATLC REMAINS 
TRANQUIL THIS MORNING WITH A BROAD AREA OF SAHARAN DUST COVERING 
THE AREA E OF 42W AND FROM 60W-72W.  

$$
WALLACE