000
AXPZ20 KNHC 090338
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED AUG 08 2007

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION NINE-E IS UPGRADED TO TROPICAL STORM 
FLOSSIE. IT WAS CENTERED NEAR 13.4N 128.3W AT 09/0300Z MOVING 
WEST AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. 
MAXIMUM SUSTAINED WINDS ARE 35 KT WITH GUSTS TO 45 KT. LATEST 
SATELLITE IMAGERY INDICATES THAT CONVECTION HAS BECOME BETTER 
ORGANIZED WITH A WELL PRONOUNCED BANDING FEATURE WEST OF THE 
CENTER. THIS TROPICAL CYCLONE APPEARS TO BE LOCATED WITHIN A 
FAVORABLE ENVIRONMENT FOR ADDITIONAL STRENGTHENING. SEE LATEST 
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 
KNHC FOR MORE DETAILS. NUMEROUS MODERATE TO STRONG CONVECTION 
WITHIN 100 NM W SEMICIRCLE AND WITHIN 30 NM E OF CENTER.     

...TROPICAL WAVES...

LARGE TROPICAL WAVE IS ALONG 109W EXTENDING FROM 23N E OF BAJA 
CALIFORNIA TO 5N IN THE EASTERN PACIFIC. IT IS MOVING W 15 KT.  
THE LOW PRES CENTER LOCATED ALONG THE WAVE AXIS HAS WEAKENED AND 
THE CONVECTIVE ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE HAS 
ALSO DIMINISHED. CONVECTION HAS FLARED UP ALONG THE MEXICAN 
COAST BETWEEN MAZATLAN AND THE CITY OF OBREGON WHERE SATELLITE 
IMAGERY SHOWS A LARGE CLUSTER OF MODERATE TO ISOLATED STRONG 
CONVECTION. A DIFFLUENT PATTERN ALOFT IS ENHANCING THIS 
CONVECTIVE ACTIVITY.  

THE TROPICAL WAVE THAT WAS PREVIOUSLY ALONG 115W/116W HAS BEEN 
DROPPED FROM THE 00Z SURFACE MAP BASED ON SATELLITE IMAGERY AND 
OBSERVATIONS.    

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N82W 11N95W 16N107W 10N115W 15N125W 
12N130W 10N140W. SCATTERED MODERATE CONVECTION IS FROM 6N TO 8N 
BETWEEN 84W AND 93W. A BAND OF SIMILAR CONVECTION IS ALONG 
14N105W 12N108W 10N110N.  

...DISCUSSION...
AT THE SURFACE...A 1032 MB HIGH PRES LOCATED WELL NW OF AREA 
EXTENDS A RIDGE SE TO 20N115W. MOSTLY BROKEN TO OVERCAST LOW 
CLOUDS WITH NO CONVECTION COVERS AREA. PRES GRADIENT TIGHTENS 
BETWEEN RIDGE AND THE LARGE TROPICAL WAVE SITUATED NEAR THE BAJA 
CALIFORNIA PENINSULA. AS A RESULT...NW WINDS OF 15 TO 20 KT ARE 
BLOWING N OF 20N E OF 120W. THIS WEATHER PATTERN WILL PERSIST AT 
LEAST 24 HOURS. A WEAK SFC TROUGH GOES FROM 25N136W TO 19N139W. 

IN THE UPPER LEVELS...AN UPPER LOW OVER THE NW CORNER OF THE 
AREA HAS AN UPPER TROUGH DIGGING S TO 20N140W. DRY AIR ALOFT 
RESULTING IN MODERATE TO STRONG SUBSIDENCE IS AHEAD OF THE 
TROUGH AXIS COVERING N OF 20N WEST OF 130W. BROAD ANTICYCLONIC 
FLOW CENTERED 21N122W COVERS MOST OF THE REMAINING E EPAC. RIDGE 
EXTENDS INTO A SECOND ANTICYCLONE OVER NW MEXICO. STRONG NE TO E 
UPPER WIND FLOW IS FOUND ON SRN PERIPHERY OF RIDGE ADVECTING MID 
TO HIGH DEBRIS MOISTURE INTO THE EPAC. AN UPPER LOW OVER 
SOUTH-CENTRAL MEXICO WITH AN INVERTED TROUGH ALONG 97W. UPPER 
DIFFLUENT BETWEEN THIS LOW AND THE ANTICLYCLONIC OVER NW MEXICO 
IS SUPPORTING THE DEVELOPMENT OF SHOWERS AND TSTMS OVER MEXICO S 
OF 20N AND W OF 100W. 

$$
GR