000
AXPZ20 KNHC 181547
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON OCT 18 2010

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...ITCZ...
THE ITCZ AXIS IS ALONG 09N84W TO 08N110W TO 08N120W TO 09N130W 
TO 09N140W. ISOLATED TO SCATTERED MODERATE CONVECTION IS WITHIN 
120 NM N OF AXIS BETWEEN 118W AND 125W.  

...DISCUSSION...
ALOFT...
A TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE N WATERS. SWLY FLOW 
AHEAD OF A DEEP LAYER TROUGH LOCATED W OF AREA IS NOTED OVER THE 
NW PORTION OF THE REGION. THE WINDS SHIFT W AND INCREASE TO 
70-90 KT OVER THE NORTH-CENTRAL WATERS THEN TURN W TO NW OVER 
THE BAJA CALIFORNIA PENINSULA AND NW MEXICO. THESE WINDS ARE 
TRANSPORTING ABUNDANT MID/UPPER LEVEL MOISTURE ACROSS THE N 
PORTION OF THE FORECAST AREA PARTICULARLY N OF 20N. AN UPPER 
LEVEL TROUGH EXTENDS FROM EASTERN TEXAS TO NEAR ACAPULCO MEXICO. 
SOME SHOWERS ARE NEAR THE BASE OF THIS TROUGH. AN ANTICYCLONIC 
CIRCULATION IS LOCATED NEAR 16N118W. A DIFFLUENT PATTERN ALOFT W 
OF THIS ANTICYCLONE IS HELPING TO INDUCE SOME CONVECTION ALONG 
THE ITCZ BETWEEN 118W AND 125W. MODERATE TO STRONG SUBSIDENCE IS 
NOTED ON THE EASTERN SIDE OF THIS SYSTEM TO NEAR 100W WHILE A 
GOOD AMOUNT OF MID/UPPER MOISTURE IS ALSO SEEN OVER THE EASTERN 
PART OF THE AREA.  

SURFACE...
A MONSOON TROUGH IS EVIDENT E OF 90W IN THE ERN PORTION OF THE 
DISCUSSION AREA. THE MOST RECENT ASCAT PASS SHOWED SW WINDS IN 
THE 10 TO 15 KT RANGE. FURTHER W...A WEAK TROUGH EXTENDS FROM 
15N136W TO 12N140W. SCATTERED MODERATE CONVECTION CAN BE FOUND 
WITHIN 60 NM AHEAD OF THE TROUGH AXIS. OTHERWISE A BROAD HIGH 
PRES RIDGE DOMINATES THE N PORTION OF AREA MAINLY N OF 15N AND W 
OF 110W. A TROUGH ENTERS THE AREA NEAR 30N119W THEN CONTINUES SW 
TO NEAR 27N125W. SURFACE DATA AND AN EARLIER ASCAT PASS SHOWED 
SOME WIND BARBS OF NLY WINDS OF 20 KT BEHIND THE TROUGH AXIS.

GAP WINDS...
VISIBLE SATELLITE PICTURE SUGGESTS THAT SOME WINDS ARE STILL 
BLOWING ACROSS THE GULF OF TEHUANTEPEC WHERE A ROPE CLOUD IS 
NOTED. 
  
$$
GR