000
AXPZ20 KNHC 060936
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI AUG 06 2010

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

BASED ON 06000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...SPECIAL FEATURE...

AT 06/0900 UTC...TROPICAL DEPRESSION SEVEN-E IS CENTERED NEAR 
16.3N 103.1W MOVING WEST-NORTHWEST OR 290 DEGREES AT 9 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED 
WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC 
FOR MORE DETAILS. THE CLOUD PATTERN ASSOCIATED WITH THE 
DEPRESSION HAS BECOME BETTER ORGANIZED DURING THE LAST COUPLE OF 
HOURS...WITH DEEP CONVECTION RE-FORMING NEAR THE ESTIMATED 
CENTER LOCATION. A HIGH RESOLUTION ASCAT PASS AT 0436 UTC SHOWED 
MAXIMUM WINDS OF ABOUT 25-30 KT. ENVIRONMENTAL CONDITIONS ARE 
FAVORABLE FOR INTENSIFICATION DURING THE NEXT 36 TO 48 HOURS.  
THE NHC OFFICIAL INTENSITY FORECAST CALLS FOR THE DEPRESSION 
TO REACH TROPICAL STORM STATUS IN ABOUT 12 HOURS. 

...ITCZ...

THE ITCZ AXIS IS ALONG 08N78W TO 09N90W TO 12N110W TO 12N122W TO 
09N130W TO 08N140W. SCATTERED MODERATE TO ISOLATED STRONG IS 
WITHIN 100 NM S OF AXIS E OF 85W. SIMILAR CONVECTION IS WITHIN 
120-140 NM S OF AXIS BETWEEN 90W AND 96W...AND FROM 10N TO 13N 
BETWEEN 106W AND 11OW. SCATTERED MODERATE IS FROM 07N TO 12N 
BETWEEN 127W AND 134W. 
 
...DISCUSSION...

ALOFT...AN UPPER LEVEL ANTICYCLONE IS OVER THE NW WATERS 
CENTERED NEAR 25N140W WITH A RIDGE EXTENDING BEYOND 30N130W. A 
SECOND UPPER LEVEL ANTICYCLONIC CIRCULATION LOCATED OVER 
SOUTH-CENTRAL UNITED STATES EXTENDS A RIDGE ACROSS NORTHERN 
MEXICO INTO THE EPAC TO NEAR 20N130W. THE DEPRESSION IS MOVING 
AROUND THE SOUTHERN PERIPHERY OF THIS RIDGE. AN UPPER LEVEL 
TROUGH ENTERS THE FORECAST AREA NEAR 30N122W AND CONTINUES SW TO 
NEAR 22N131. AT THIS POINT...AN INVERTED TROUGH IS NOTED 
EXTENDING TO NEAR 14N136W. VERY DRY AIR ALOFT UNDER MODERATE TO 
STRONG SUBSIDENCE IS PRESENT ACROSS THE AREA N OF 20N AND W OF 
116W. ANOTHER INVERTED TROUGH RUNS FROM 24N114 W TO A SMALL 
CYCLONIC CIRCULATION NEAR 17N118W. EASTERLY/ZONAL FLOW PREVAILS 
ACROSS THE REMAINDER OF THE DISCUSSION AREA IN THE DEEP TROPICS 
S OF 10N. UPPER LEVEL MOISTURE RESULTING FROM ITCZ CONVECTION IS 
BEING ADVECTED TO THE WEST AS A RESULT OF THE PERSISTENT 
EASTERLY WINDS.

AT THE SURFACE...A RIDGE DOMINATES THE N WATERS MAINLY N OF 18N. 
PRES GRADIENT BETWEEN THIS RIDGE A LOWER PRES OVER NW MEXICO IS 
PRODUCING NW OF 20 KT N OF 25N E OF 118W TO THE W COAST OF BAJA 
CALIFORNIA. THE EDGE OF A HIGH RESOLUTION ASCAT PASS FROM AROUND 
0440 UTC CONFIRMED THESE WIND SPEEDS. 

A TROUGH EXTENDS FROM 14N127W TO 11N134W. NE WINDS OF 20 KT AND 
SEAS OF 8 FT ARE OCCURRING WITHIN 150 NM NW OF THE TROUGH AXIS N 
OF 12N. THESE MARINE CONDITIONS WILL PERSIST AHEAD OF THE TROUGH 
AXIS DURING THE NEXT COUPLE OF DAYS AS THE TROUGH MOVES WWD.  

ITCZ DISTURBANCES ARE GENERATING AN AREA OF S-SW WINDS OF 20 KT 
MAINLY FROM 03N TO 08N BETWEEN 90W AND 105W. THIS WEATHER 
PATTERN IS FORECAST TO PERSIST BY THE COMPUTER MODELS OVER THE 
NEXT COUPLE OF DAYS REACHING 125W IN ABOUT 24 HOURS.  

REGIONAL SEAS ARE DOMINATED BY LONG PERIOD SW SWELLS OF 15 TO 17 
SECONDS RAISING SEAS TO 9 FT MAINLY S OF 12N BETWEEN 100W AND 
120W. THE SWELLS WILL CONTINUE TO PROPAGATE ACROSS THE BASIN 
WITH OPEN OCEAN SEAS OF 8 TO 10 FT THROUGH 48 HOURS.

$$
GR