000
AXPZ20 KNHC 212111
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI SEP 21 2007

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2145 UTC.

...SPECIAL FEATURE...
THE CENTER OF TROPICAL STORM IVO AT 21/2100 UTC IS NEAR 20.1N 
113.4W OR 265 NM SOUTHWEST OF CABO SAN LUCAS MEXICO. IVO IS 
MOVING NORTH AT 5 KT.  THE MAXIMUM SUSTAINED WIND SPEEDS ARE 60 
KT WITH GUSTS TO 75 KT.  THE ESTIMATED MINIMUM CENTRAL PRESSURE 
IS 990 MB.  PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS.  GOOD 
UPPER LEVEL HIGH PRESSURE OUTFLOW IS NOTED OVER IVO.  EVEN 
THOUGH IVO WAS RECENTLY DOWNGRADED FROM A HURRICANE A RECENT 
BURST OF CONVECTION IS NOTED NEAR THE CENTER.  SCATTERED 
MODERATE TO STRONG CONVECTION IS FROM 18N TO 22N BETWEEN 111W 
AND 114W.  
  
...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 96W/97W SOUTH OF 17N MOVING WEST 10 KT. 
CONVECTION IS CONFINED TO THE ITCZ AND JUST N OF THE ITCZ.  
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 8N TO 13N 
BETWEEN 91W AND 100W.  

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N80W 12N90W 13N100W 17N107W 15N120W 
18N130W 13N140W.  SCATTERED MODERATE CONVECTION IS S OF COSTA 
RICA FROM 4N TO 6N BETWEEN 79W AND 83W...AND FROM 6N TO 9N 
BETWEEN 84W AND 88W.  SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION IS FROM 10N TO 13N BETWEEN 108W AND 110W...AND FROM 
10N TO 12N BETWEEN 118W AND 123W.    

...DISCUSSION...
ITCZ CONVECTION IS INCREASING E OF 100W AS AN UPPER RIDGE 
BUILDING W NEAR 106W INTERACTS WITH THE DEEP UPPER TROUGH OVER 
THE WESTERN GULF PROVIDING AN EFFICIENT OUTFLOW CHANNEL FOR 
THUNDERSTORM ACTIVITY OVER CENTRAL AMERICA.  FURTHER NORTH 
ANOTHER DEEP TROUGH W OF S CALIFORNIA IS FUNNELING TROPICAL 
MOISTURE ACROSS BAJA CALIFORNIA INTO AZ NM AND THE SOUTHERN 
ROCKIES.  BETWEEN THE TWO UPPER TROUGHS A HIGH AMPLITUDE N-S 
ORIENTED RIDGE IS PARKED ALONG 110W-120W.  THE LARGE CUT-OFF LOW 
OFF THE CALIFORNIA COAST HAS BROAD CYCLONIC FLOW EXTENDING N OF 
20N BETWEEN BAJA CALIFORNIA AND 135W.  A SURFACE LOW IS SW OF 
LOS ANGELES NEAR 32N122W WITH A SFC TROUGH EXTENDING SW TO 
27N126W.  THE LOW HAS DRAGGED A LARGE AREA OF DRY AIR SWD W OF 
115W INTO THE REMNANT CIRCULATION OF T.D. 13-E. THE REMNANT LOW 
IS NEARLY STATIONARY NEAR 16N131W WITH A CENTRAL PRESSURE OF 
1009 MB.  OCCASIONAL FLAREUPS OF SCATTERED MODERATE TO ISOLATED 
STRONG CONVECTION ARE OCCURRING NEAR THE CIRCULATION CENTER FROM 
15N TO 17N BETWEEN 130W AND 133W AS THE SYSTEM STRUGGLES TO 
SURVIVE IN AN ENVIRONMENT HOSTILE FOR TROPICAL CYCLONES TO 
REGENERATE.

$$
FORMOSA