000
AXPZ20 KNHC 250230
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC FRI SEP 25 2015

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM  
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.               

...TROPICAL LOW AND TROPICAL WAVES... 

A 1006 MB SURFACE LOW IS EMBEDDED IN THE MONSOON TROUGH AT  
12N91W AND IS NEARLY STATIONARY AND DISORGANIZED. CURRENTLY 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WELL S OF 
THE ESTIMATED CENTER WITHIN 30 NM EITHER SIDE OF A LINE FROM 
11N90W TO 10N93W.  THIS LOW IS EXPECTED TO CONTINUE 
NORTHWESTWARD WITH CONDITIONS BECOMING FAVORABLE FOR TROPICAL 
CYCLONE FORMATION IN ABOUT 3 DAYS.

A BROAD TROPICAL WAVE IS ANALYZED FROM 06-15N BETWEEN 99-101W    
...AND HAS BEEN MOVING W AT 5 KT. SCATTERED MODERATE ISOLATED
STRONG CONVECTION IS OBSERVED S OF 12N WITHIN 180 NM E AND 240
NM W OF WAVE AXIS.

A TROPICAL WAVE WAS ANALYZED FROM 04N133W TO 19N123W WITH     
SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED S OF 11N 
WITHIN 150 NM W OF WAVE AXIS...AND WELL W OF THE WAVE WITHIN 90 
NM OF 14N133W.  
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            

THE MONSOON TROUGH AXIS EXTENDS W FROM THE CARIBBEAN COAST OF   
COLOMBIA AT 11N76W THEN CROSSES COSTA RICA ALONG 10N REACHING 
THE PACIFIC COAST OF COSTA RICA AT 11N86W...THEN EXTENDS NW TO 
THE EMBEDDED LOW PRES AT 12N91W...THEN DIPS SW TO 09N100W AND 
CONTINUES W TO 10N120W WHERE IT LOSES IDENTITY. EXCEPT AS 
PREVIOUSLY DESCRIBED IN ASSOCIATION WITH TROPICAL LOW AND 
TROPICAL WAVES...SCATTERED MODERATE ISOLATED STRONG CONVECTION 
IS OBSERVED WITHIN 240 NM EITHER SIDE OF A LINE FROM 12N90W TO 
07N112W TO 09N126W. 

...DISCUSSION...

A SURFACE RIDGE EXTENDS FROM 32N128W TO 12N120W. THE PRESSURE 
GRADIENT E OF THE RIDGE WILL TIGHTEN LATE SAT INCREASING THE 
NORTHERLY FLOW TO 15-20 KT ACROSS THE DISCUSSION AREA TO THE N 
OF 29N BETWEEN 120-127W...WITH SEAS BUILDING TO 7 FT. THE 
GRADIENT WILL RELAX AGAIN ON SUN. A WEAK COLD FRONT WILL ENTER 
THE FAR NW PORTION OF THE DISCUSSION AREA NEAR 30N140W ON FRI... 
AND CONTINUE SE REACHING A POSITION FROM 32N135W TO 26N136W LATE 
SAT NIGHT. BY THEN STRENGTHENING HIGH PRESSURE NW OF THE FRONT
WILL INCREASE THE POST-FRONTAL NW FLOW TO 20-25 KT WITH COMBINED
SEAS BUILDING TO 12 FT NEAR 32N140W.
  
GAP WINDS...PULSES OF STRONG N-NE WINDS ARE EXPECTED ACROSS AND 
DOWNSTREAM OF THE GULF OF TEHUANTEPEC THROUGH THE WEEKEND WITH 
THE STRONGEST WINDS EXPECTED DURING MAXIMUM DRAINAGE AROUND 
SUNRISE EACH MORNING WITH SEAS BUILDING TO A MAX OF 12 FT
DOWNSTREAM OF THE GULF OF TEHUANTEPEC NEAR 14.5N96W.  
    
$$
NELSON