000
AXPZ20 KNHC 262212
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE OCT 26 2010

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 
2100 UTC.

...ITCZ...
AXIS FROM FROM LOW PRES AT 10N90W TO 08N96W TO 11N115W TO 
07N132W TO 09N140W.  SCATTERED MODERATE WITHIN 90 NM N OF AXIS 
W OF 131W.

...DISCUSSION...
COMPLEX UPPER LEVEL PATTERN INCLUDE TWO WELL DEFINED CYCLONIC 
VORTICES AND TWO BROAD ANTICYCLONIC GYRES STRUGGLING TO CONTROL 
WIND FLOW ACROSS E PAC.  THE TWO CYCLONES...ONE AT 03N127W AND 
THE OTHER AT 19N137W...KEEP A MOIST COOLER NW FLOW ALOFT ON 
THEIR WESTERN SIDE WHILE PULLING DRY AIR MASS N ON THEIR EASTERN 
SIDES.  

DOWNSTREAM FROM CYCLONES...ANTICYCLONES LOCATED AT 18N117W AND 
26N111W EXPAND DRY SLOT WITH SUBSIDING AIR MASS E OF 110W.  ONLY 
FLY IN THE OINTMENT IS DIVERGING FLOW ALOFT BETWEEN SOUTHERNMOST 
GYRE AND CYCLONE COINCIDING OVER SURFACE LOW PRES AT 11N118W.
SCATTERED MODERATE CONVECTION NOTED WITHIN 90 NM OF CENTER 
EXPECTED TO LAST 24-36 HRS BEFORE COLLAPSING UNDER INCREASED SW 
SHEARING WINDS ALOFT. 

ELSEWHERE AT THE SURFACE...
PACIFIC COLD FRONT BRINGS STRONG N WINDS N OF 28N E OF 124W 
REACHING GALE FORCE N OF 30N.  FRONT BRING NEW TRAIN OF LARGE 
LONG PERIOD NW SWELLS...UP TO 15 FT...SPREADING SE ACROSS BASIN 
N OF 13N.  FRONT FORECAST TO DISSIPATE TONIGHT WITH WINDS 
DIMINISHING BELOW 20 KT WED...BUT LINGERING SWELL REMAIN BEYOND 
48 HRS. 

NEW COLD FRONT FORECAST TO MOVE INTO NW WATERS WED NIGHT WITH 
LITTLE IN THE WAY OF WINDS STRENGTH...BUT FORCING NEW TRAIN OF 
HIGHER SWELLS N OF 25N BEYOND FORECAST PERIOD.

STRING OF LOW PRES SYSTEMS EMBEDDED IN ITCZ DO NOT SEEM TO POSE 
THREAT OF DEVELOPING TROPICAL CHARACTERISTIC DUE TO DRY AIR MASS 
...COOL SSTS AND STRENGTH OF UPPER LEVEL WINDS.  MODEL GUIDANCE 
INITIALIZE LOW PRES CENTERS WELL...BUT DO NOT FAVOR DEVELOPMENT 
OF ANY OF THEM.  EASTERNMOST LOW PRES CENTER AT 10N90W FORCES 
FRESH SW MONSOONAL FLOW AGAINST COAST OF COLOMBIA...PANAMA AND 
COSTA RICA...BUT FLOW BECOMES MODERATE AS LOW PRES WEAKENS AND 
DRIFT NW.  WESTERNMOST LOS PRES AT 09N139W MOVE OUT OF BASIN 
TONIGHT WITH ASSOCIATED FRESH WINDS DIMINISHING BELOW 20 KT. 

ONSET OF STRONG N TEHUANTEPEC WINDS JUST BY END OF FORECAST 
PERIOD MAY BE PRELUDE OF NEXT GALE EVENT IN REGION. 

$$
WALLY BARNES