000
AXPZ20 KNHC 091011
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE OCT 09 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 133W HAS MOVED W 15 KT OVER THE PAST 24 
HOURS. SCATTERED MODERATE ISOLATED STRONG CONVECTION FLARED FROM 
11N TO 14.5N WITHIN 90 NM EITHER SIDE OF THE WAVE AXIS...BUT IS 
CURRENTLY DISSIPATING. THE WAVE IS MOVING INTO AN AREA OF STRONG 
SW UPPER LEVEL WINDS...AND ANY MORE TSTM DEVELOPMENT WILL 
ARRESTED BY HOSTILE SHEAR.   

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE...AXIS 13N88W 11N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 10N TO 14N 
BETWEEN 102W AND 112W AND WITHIN 60 NM OF LINE 10N123W 10N134W. 

...DISCUSSION...
AN UPPER LEVEL TROUGH EXTENDS SW INTO THE DISCUSSION AREA ALONG 
34N123W 28N140W...AND WILL BE REINFORCED BY A SERIES OF UPPER 
SHORTWAVE OVER THE NEXT FEW DAYS. AN UPPER LEVEL ANTICYCLONE IS 
OVER OLD MEXICO AT 28N102W WITH A RIDGE EXTENDING SW ALONG 
17N120W TO A SHARP CREST AT 11N143W. AN UPPER LEVEL MOISTURE 
PLUME...ORIGINATING FROM ITCZ CONVECTION WELL W OF AREA NEAR 
12N155W...IS OBSERVED WITHIN 120 NM EITHER SIDE OF LINE 24N131W 
20N140W. UPPER MOISTURE IS SPREADING SE INTO THE NW CORNER OF 
THE DISCUSSION AREA IN ADVANCE OF THE FIRST REINFORCING UPPER 
TROUGH. OTHERWISE...THE UPPER LEVELS ARE DRY N OF 20N. UPPER 
MOISTURE ORIGINATING FROM ITCZ CONVECTION BETWEEN 100W AND 140W 
IS ADVECTED N UNDER THE UPPER RIDGE...BUT IS EVAPORATING TO THE 
S OF 18N.

AN UPPER LEVEL ANTICYCLONE OVER THE W CARIBBEAN NEAR 14N77W HAS 
AN UPPER RIDGE EXTENDING SW ACROSS CENTRAL AMERICA AND OVER THE 
E PAC WATERS N OF 8N E OF 90W. AN UPPER TROUGH SEPARATES THIS  
ANTICYCLONIC FLOW FROM THE FLOW ASSOCIATED WITH THE ANTICYCLONE 
NEAR  28N102W...RESULTING IN WEAK UPPER TROUGH N OF 5N ALONG 
95W. UPPER DIFFLUENCE IS ENHANCING SPORADIC ITCZ CONVECTION E OF 
100W.  
  
AT THE LOW LEVELS...A COLD FRONT JUST NW OF AREA WILL MOVE INTO 
AREA TODAY AND SLIDE E REMAINING TO THE N OF A RIDGE LYING W TO 
E ALONG 25N. THE RIDGE WILL STALL THE FRONT ALONG ROUGHLY 27N IN 
ABOUT 36 HOURS...WITH ANOTHER COLD FRONT SLIPPING INTO THE NW 
PORTION LATE THU. 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 THU AFTERNOON...AND DECAYING 
SWELLS TO 8 FT REACHING SOUTHERN TIP OF BAJA FRI AFTERNOON.  

THE LOW LEVEL FLOW BECOMES SW TO THE SE OF LINE 18N103W 9N123W 
WITH 20 TO 25 KT WINDS AND SEAS 8 TO 11 FT IN AREA FROM 3N TO 
12N BETWEEN 122W AND 89W...EXPECT LITTLE CHANGE THROUGH 48 
HOURS.    

LOW PRES NEAR THE YUCATAN PENINSULA AT 18N87W IS EXPECTED TO 
PERSIST WITH POSSIBLE TROPICAL CYCLONE DEVELOPMENT. THIS IN TURN 
IS CONTINUING THE NW TO N LOW LEVEL FLOW IN THE BAY OF CAMPECHE. 
EXPECT INTERMITTENT BRIEF N SURGES INTO GULF OF TEHUANTEPEC... 
MOSTLY AT 15 KT...FOR THE NEXT FEW DAYS. IF LOW PRES DOES DEEPEN 
IN CARIBBEAN...WINDS MAY INCREASE RAPIDLY THROUGH THE 
TEHUANTEPEC GAP.      

$$
NELSON