000
AXPZ20 KNHC 101003
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED OCT 10 2007

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 0945 UTC.
  
...TROPICAL WAVE...
A TROPICAL WAVE ALONG 138W IS ESTIMATED TO BE MOVING W AT 12 KT. 
ISOLATED MODERATE AND STRONG CONVECTION IS NOTED WITHIN 75 NM 
EITHER SIDE LINE 10N132W 15N138W...BUT IS CURRENTLY WEAKENING. 
THE WAVE IS MOVING W UNDER AN UPPER RIDGE THAT AMPLIFIED W OVER 
THE PAST 24 HOURS SUPPORTING THE CONTINUED CONVECTION. THE UPPER 
ENVIRONMENT WILL BECOME LESS FAVORABLE FOR TSTM ACTIVITY AS THE 
WAVE MOVES W OF 140W.

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE...AXIS 3N88W 15N107W 11N140W. 
ISOLATED MODERATE AND STRONG CONVECTION IS OBSERVED FROM 7N TO 
14N BETWEEN 85W AND 102W...AND WITHIN 90 NM OF 15N113W...AND 
WITHIN 75 NM EITHER SIDE LINE 10N132W 15N138W ASSOCIATED WITH 
THE TROPICAL WAVE.

...DISCUSSION...
A SERIES OF UPPER LEVEL TROUGHS OVER THE NW PORTION HAS A MEAN 
AXIS ALONG 35N127W 24N140W. AN UPPER LEVEL ANTICYCLONE IS OVER 
OLD MEXICO AT 26N105W...WITH A RIDGE EXTENDING SW ALONG 18N120W 
14N140W TO A SHARP CREST W OF THE AREA AT 13N151W. AN UPPER 
LEVEL MOISTURE PLUME...ORIGINATING FROM FORMER ITCZ CONVECTION 
WELL W OF AREA NEAR 12N155W...CONTINUES TO MOVE NE WITHIN 120 NM 
EITHER SIDE OF LINE 27N124W 18N140W...BUT IS EVAPORATING S OF 
20N. A THIN BAND OF UPPER MOISTURE IS EVAPORATING WITHIN 60 NM 
OF LINE 32N125W 27N140W. DEBRIS MOISTURE FROM ITCZ CONVECTION 
BETWEEN 128W AND 138W IS SPREADING N UNDER THE UPPER RIDGE TO 
NEAR 18N135W. OTHERWISE...THE UPPER LEVELS ARE DRY N OF 20N...
AND FROM 20N TO 12N BETWEEN 120W AND 130W.

AN UPPER LEVEL ANTICYCLONE OVER THE W CARIBBEAN NEAR 16N79W HAS 
AN UPPER RIDGE EXTENDING SW ACROSS CENTRAL AMERICA AND OVER THE 
TROPICAL E PAC WATERS MERGING ALONG 100W WITH THE ANTICYCLONIC 
FLOW ASSOCIATED THE UPPER ANTICYCLONE NEAR 26N105W. A MOSTLY MID 
LEVEL TROUGH IS NOTED UNDER THIS UPPER FLOW...EXTENDING SW FROM 
A LOW TO MID LEVEL CYCLONE AT 18N88W TO NEAR 10N103W. THE RESULT 
IS A LARGE AREA OF UPPER DIFFLUENCE FROM 6N TO 22N BETWEEN 100W 
AND 70W...THAT ENHANCED CLUSTERS OF CONVECTION. THE DEBRIS 
MOISTURE HAS REMAINED IN ROUGHLY THE SAME AREA.
  
AT THE LOW LEVELS...A COLD FRONT HAS MOVED INTO THE AREA ALONG 
30N126W 27N140W. HIGH PRES TO ITS S WILL BLOCK SE MOVEMENT TO 
ALONG 26N TO 27N W OF 125W WHILE THE N SEGMENT WILL REACH S 
CALIFORNIA IN 24 HOURS. THE REMNANTS OF THIS FRONT WILL BE 
OVERRUN BY A SECOND COLD FRONT MOVING INTO THE NW CORNER ABOUT 
12Z FRI. ONLY EXPECTING A BRIEF 20 KT WIND SHIFT ALONG BOTH 
FRONTAL BOUNDARIES...BUT NW SWELLS 8 TO 12 FT WILL MOVE INTO THE 
AREA BEHIND EACH FRONT...WITH THE 8 FT NW SWELLS REACHING BAJA 
PENINSULA AT 30N LATE THU MORNING AFTERNOON...AND DECAYING 
SWELLS TO 7 FT PASSING THE SOUTHERN TIP OF THE BAJA PENINSULA 
FRI AFTERNOON...AND ALONG 10N BETWEEN 125W AND 105W SAT 
AFTERNOON. 

THE LOW LEVEL FLOW BECOMES SW TO THE SE OF LINE 17N100W 10N120W 
WITH 20 TO 25 KT WINDS AND SEAS 8 TO 11 FT IN AREA FROM 7N TO 
12N BETWEEN 110W AND 85W. EXPECTING THE SLY FLOW TO INCREASE TO 
20 KT ALL WATERS S OF 12N E OF 117W IN ABOUT 48 HOURS.    

LOW PRES OVER THE YUCATAN PENINSULA AT 19N88W IS EXPECTED TO 
PERSIST AND MAY POSSIBLY DRIFT W INTO THE EASTERN BAY OF 
CAMPECHE THIS WEEKEND. NLY FLOW IS AT 20 TO 25 KT OVER THE SW 
GULF OF MEXICO INCLUDING THE WESTERN BAY OF CAMPECHE. EXPECTING 
INTERMITTENT BRIEF NLY SURGES INTO GULF OF TEHUANTEPEC...MOSTLY 
AT 15 KT...FOR THE NEXT FEW DAYS. IF THIS LOW PRES DOES DEEPEN 
IN CARIBBEAN...NLY WINDS MAY INCREASE RAPIDLY THROUGH THE 
TEHUANTEPEC GAP.      

$$
NELSON