000
AXPZ20 KNHC 221005
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC TUE SEP 22 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.                
 
...TROPICAL WAVES... 

TROPICAL WAVE AXIS IS NEAR 114W FROM 08N TO 17N MOVING W 15-20 
KT. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM OF 09N114W.
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            

MONSOON TROUGH AXIS EXTENDS FROM NW COLOMBIA AT 10N75W TO 10N82W 
TO 10N95W TO 10N110W WHERE IT REMAINS FRACTURED. IT RESUMES FROM 
1009 MB LOW PRES NEAR 14N123W TO 13N127W TO BEYOND 12N140W. 
NUMEROUS STRONG CONVECTION IS WITHIN 60 NM N OF THE TROUGH 
BETWEEN 136W-139W. SCATTERED STRONG CONVECTION IS WITHIN 180 NM 
S AND 60 NM N OF THE TROUGH BETWEEN 133W-136W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS SEEN FROM 09N-13N BETWEEN 
87W AND 90W. 
 
...DISCUSSION...

RATHER TRANQUIL CONDITIONS ARE BEING OBSERVED ACROSS THE AREA. A 
BROAD UPPER TROUGH ADVANCING EASTWARD ACROSS THE EASTERN PORTION 
OF THE AREA IS N OF 21N BETWEEN 113W-127W. AN UPPER LOW WITHIN 
THE TROUGH IS NEAR 31N119W...AND MOVING ENE TOWARDS FAR SOUTHERN 
CALIFORNIA. THE LOW IS ATTENDED BY LIMITED MOISTURE AS NOTED ON 
WATER VAPOR IMAGERY. TO THE E OF THE TROUGH...A LARGE UPPER 
ANTICYCLONE IS CENTERED OVER NW MEXICO AT 26N107W...WHILE TO ITS 
S A LARGE UPPER LOW IS AT 14N109W. THE UPPER FLOW BETWEEN BOTH 
THESE SYSTEMS IS STEERING SCATTERED TSTM ACTIVITY WESTWARD THAT 
IS OCCURRING FROM 13N-17N AND BETWEEN 107W-115W. OVER THE 
WESTERN PORTION OF THE AREA...A LARGE UPPER ANTICYCLONE IS NEAR 
18N131W WITH ASSOCIATED RIDGING PRESENT S TO 11N AND W OF 122W. 
A DIFFLUENT FLOW PATTERN SEEN TO THE SW OF THE ANTICYCLONE IS 
PROVIDING VENTILATION FOR CLUSTERS OF NUMEROUS STRONG CONVECTION 
NOTED FROM 09N-13N BETWEEN 136W-130W...AND THE SCATTERED STRONG 
CONVECTION WITHIN 60 NM N OF THE TROUGH BETWEEN 133W-136W. WATER 
VAPOR IMAGERY SHOWS MODERATE SUBSIDENCE ALOFT FROM 17N-29N 
PROVIDING FOR STABLE ATMOSPHERIC CONDITIONS. THIS IS ALLOWING 
FOR SCATTERED TO BROKEN LOW CLOUDS WITH POSSIBLE ISOLATED 
SHOWERS TO BE EXIST THERE.

OVER THE EASTERN PORTION...THE NLY FLOW ALOFT E OF AN UPPER 
RIDGE THAT STRETCHES NW TO SE ACROSS THE INTERIOR OF MEXICO IS 
IS STEERING SOUTHWARD LARGE CLUSTERS OF STRONG CONVECTION 
THAT ARE WITHIN 60 NM OF A LINE FROM 15N93W TO 14N96W TO 
13N98W.

HIGH PRES OF 1026 MB IS CENTERED WELL NW OF THE AREA AT 39N146W 
WITH A RIDGE EXTENDING SE TO NEAR 25N127W. THE PRES GRADIENT 
BETWEEN THE RIDGE AND THE MONSOON TROUGH IS PRODUCING MODERATE 
TO LOCALLY FRESH NE TRADE WINDS OVER WESTERN PORTIONS OF THE 
AREA FROM ABOUT 13N-118N W OF 132W. THESE WINDS HAVE BUILD SEAS 
TO THE 6-8 FT RANGE THERE OVER THE PAST FEW DAYS. THE RIDGE IS 
FORECAST TO WEAKEN OVER THE NEXT 24-48 HOURS AS A COLD FRONT 
PUSHES SE JUST TO THE N OF THE AREA WHILE IT ALSO WEAKENS. 
 
GAP WINDS...A PULSING OF NORTHERLY FLOW THROUGH THE GULF OF 
TEHUANTEPEC WITH WINDS OF 20-30 KT WITH RESULTANT SEAS TO 10 FT  
WILL DIMINISH TO 15-20 KT THIS AFTERNOON...THEN START UP AGAIN 
TONIGHT WITH SEAS BUILDING UP TO 10 OR 11 FT. THESE WINDS ARE  
THEN FORECAST TO DIMINISH TO 20-25 KT WED AFTERNOON AND CONTINUE 
INTO THU NIGHT WITH SEAS OF 8-10 FT.
 
$$
AGUIRRE