000
AXPZ20 KNHC 201524
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON OCT 20 2008

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...

ITCZ AXIS IS CENTERED ALONG 07N79W TO 11N86W TO 07N100W TO 
08N107W TO 07140W. SCATTERED MODERATE CONVECTION CAN BE FOUND 
WITHIN 30 NM OF AXIS E OF 80W AND WITHIN 60 NM OF THE COLOMBIAN 
COAST N OF 04N.

...DISCUSSION...

WINDS THROUGH THE GULF OF TEHUANTEPEC HAVE DIMINISHED SLIGHTLY 
AS HIGH PRES OVER THE GULF OF MEXICO HAS WEAKENED AND SHIFTED 
EAST. ALTHOUGH WINDS ARE LESS THAN GALE FORCE...STRONG WINDS 
PERSIST. A SCATTEROMETER PASS FROM 13Z SHOWS 20 TO 25 KT WINDS 
TO THE SOUTH OF THE GULF OF TEHUANTEPEC...AND IT IS PLAUSIBLE 
THAT WINDS TO 30 KT ARE STILL BLOWING NEAR THE COAST. THESE WILL 
DIMINISH GRADUALLY TO 20 TO 25 KT OVER THE NEXT COUPLE OF DAYS. 
SCATTEROMETER ALSO SHOWS 20 KT SOUTHERLY FLOW IN A BROAD AREA 
SOUTH OF THE ITCZ. THE STRONG GAP NORTHERLY GAP WINDS AND THE 
SOUTHERLY FLOW HAVE PERPETUATED A WEAK LOW PRES AREA TO THE 
SOUTH OF TEHUANTEPEC. 

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 15N100W WITH AN 
UPPER RIDGE AXIS EXTENDING E ALONG 15N THROUGH NORTHERN CENTRAL 
AMERICA...PROVIDING MODERATE EASTERLY SHEAR ACROSS THE LOW AND 
ITCZ. DEEP LAYER MOISTURE IS NOT PARTICULARLY ABUNDANT...AND 
CONVECTION IS MODEST NEAR THE LOW. UPPER DIFFLUENCE ON THE EAST 
SIDE OF A WEAK UPPER LOW IS EVIDENT NEAR 12N113W IS ENHANCING 
MODEST CONVECTION ALONG THE ITCZ AND SUSTAINING A 1011 MB 
SURFACE LOW NEAR 09N109W. 

FURTHER NORTH...SCATTEROMETER DATA SHOW 20 KT NORTHERLY FLOW OFF 
THE LENGTH OF THE BAJA COAST...ON THE EASTERN PERIPHERY OF 1026 
MB HIGH PRES NEAR 32N140W. A BROAD SWATH OF 20 TO 25 KT TRADES 
IS EVIDENT S OF THE SURFACE HIGH...MAINLY FROM 10N TO 20N W OF 
120W. THE HIGH PRES WILL WEAKEN AS AN UPPER TROUGH DIGS INTO THE 
NE PACIFIC THROUGH WED.

$$
CHRISTENSEN