000
AXPZ20 KNHC 221509
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1300 UTC.               
 
...TROPICAL WAVES... 

A TROPICAL WAVE WAS ANALYZED ALONG 95W FROM 04N-15N. THE WAVE 
WAS MOVING W AROUND 10-15 KT. SCATTERED MODERATE TO STRONG 
CONVECTION WAS WITHIN 300 NM E AND 240 NM W FROM 11N-15N.

A TROPICAL WAVE WAS ANALYZED FROM 16N115W TO 07N120W. THE WAVE 
WAS MOVING W AROUND 10-15 KT. SCATTERED MODERATE CONVECTION 
WAS FROM 04N-10N BETWEEN 116W-123W. 
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            

THE MONSOON TROUGH AXIS WAS ANALYZED FROM 07N78W TO 09N100W TO 
13N108W...THEN CONTINUES FROM 14N122W TO 12N126W TO 13N135W TO 
12N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS 
FROM 04N-10N E OF 93W. NUMEROUS MODERATE TO STRONG CONVECTION 
WAS FROM 09N-15N W OF 134W. 
 
...DISCUSSION...

A WEAK SURFACE RIDGE EXTENDS FROM 32N134W TO 1015 MB HIGH PRES 
NEAR 23N122W TO 14N104W. PRIMARILY LIGHT TO GENTLE WINDS CAN BE 
FOUND N OF THE MONSOON TROUGH BETWEEN 110W AND 130W. THE RIDGE 
IS EXPECTED TO REMAIN WEAK THROUGH THE FORECAST PERIOD. 

THE PRESSURE GRADIENT BETWEEN THE RIDGE AND TROUGHING OVER 
CENTRAL MEXICO IS SUPPORTING A MODERATE TO FRESH N-NW BREEZE 
FROM THE MOUTH OF THE GULF OF CALIFORNIA SOUTHWARD TO OFF THE 
COAST OF MANZANILLO. THESE WINDS ARE EXPECTED TO PULSE AS THE 
PRESSURE OVER MAINLAND MEXICO LOWERS OVERNIGHT...WITH THE 
TIGHTEST PRESSURE GRADIENT AND STRONGEST WINDS EXPECTED DURING 
THE OVERNIGHT HOURS. 

MODERATE TO FRESH E-NE TRADE WIND FLOW IS CONFINED TO JUST N OF 
THE MONSOON TROUGH W OF 135W. THIS IS ALSO AN AREA OF NUMEROUS 
MODERATE TO STRONG CONVECTION. WINDS AND SEAS MAY BE HIGHER IN 
THIS AREA OF CONVECTION. THE CONVECTION IS EXPECTED TO REMAIN 
STRONG HERE INTO WED AS THE DIFFLUENT REAR RIGHT QUADRANT OF AN 
UPPER JET HOVERS OVER W WATERS. THE JET IS EXPECTED TO PULL NE 
LATE WED AND PHASE WITH THE NORTHERN STREAM.
 
GAP WINDS...THE PRESSURE GRADIENT BETWEEN WEAK RIDGING IN THE 
GULF OF MEXICO AND THE TROPICAL WAVE CURRENTLY ALONG 95W IS 
DRIVING N TO NE WINDS THROUGH CHIVELA PASS. WINDS WERE BELIEVED 
TO HAVE REACHED 30 KT IN THE GULF OF TEHUANTEPEC WITH THE 
ASSISTANCE OF NOCTURNAL DRAINAGE FLOW THIS MORNING. WINDS WILL 
EXPERIENCE THIS DIURNAL PULSE THROUGH THE END OF THE FORECAST 
PERIOD THU MORNING...WITH THE STRONGEST WINDS EXPECTED IN THE 
EARLY MORNING HOURS. AS THE TROPICAL WAVE CONTINUES W...THE 
STRENGTH OF THE WINDS IN THE GULF OF TEHUANTEPEC WILL GRADUALLY 
WEAKEN BUT IS EXPECTED TO REMAIN ABOVE THE ADVISORY CRITERIA OF 
20-25 KT THROUGH THE END OF THE FORECAST PERIOD. 
 
$$
SCHAUER