000
AXPZ20 KNHC 210257
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
0405 UTC MON SEP 21 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 
0200 UTC.               

...SPECIAL FEATURES...

TROPICAL DEPRESSION SIXTEEN-E...LOCATED NEAR 26.2N 113.6W 1003 
MB AT 0300 UTC SEP 21 MOVING N OR 010 DEG AT 13 KT. MAXIMUM 
SUSTAINED WINDS 30 KT GUSTS 40 KT...AS INDICATED BY AFTERNOON 
SCATTEROMETER DATA. SCATTERED TO LOCALLY NUMEROUS STRONG 
CONVECTION IS OCCURRING WITHIN 270 NM ACROSS THE NE 
SEMICIRCLE...AND EXTENDS INLAND ACROSS THE MEXICAN STATE OF 
SONORA...WHILE SCATTERED MODERATE CONVECTION IS WITHIN 90 SE 
QUADRANT. T.D. SIXTEEN-E IS EXPECTED TO MAINTAIN A NORTHWARD 
MOTION TONIGHT...AND MOVE INLAND ACROSS CENTRAL BAJA CALIFORNIA 
OVERNIGHT...THEN RE-EMERGE ACROSS THE NORTHERN GULF OF 
CALIFORNIA MONDAY MORNING AND THEN MOVE INLAND AGAIN ACROSS THE 
STATE OF SONORA MEXICO MONDAY AFTERNOON. 

ATMOSPHERIC CONDITIONS...AND THE FORECAST INTERACTION WITH LAND 
DO NOT APPEAR TO PROVIDE CONDUCIVE CONDITIONS FOR STRENGTHENING. 
THE MAIN THREAT FOR THIS SYSTEM REMAINS HEAVY RAINFALL THAT WILL 
OCCUR WITH AND WELL AHEAD OF THE DEPRESSION ACROSS BAJA 
CALIFORNIA...NW MAINLAND MEXICO...SOUTHERN CALIFORNIA...AND THEN 
ACROSS ARIZONA IN THE COMING DAYS. THESE RAINS COULD PRODUCE 
LIFE THREATENING FLASH FLOODS AND LEAD TO MUDSLIDES...ESPECIALLY 
ACROSS THE MOUNTAINOUS TERRAIN OF MEXICO.

MARINE CONDITIONS WITHIN THE GULF OF CALIFORNIA HAVE 
DETERIORATED SIGNIFICANTLY DURING THE PAST 24 HOURS...AS SOUTH 
TO SOUTHEAST WINDS OF 20 TO 30 KT ARE RUNNING STRAIGHT UP THE 
GULF...AND HAVE GENERATED SEAS TO AROUND 9 FT THIS EVENING. 
THESE CONDITIONS...WITH HIGHER WINDS AND SEAS NEAR SQUALLS AND 
THUNDERSTORMS WILL PERSIST ACROSS THE CENTRAL GULF AND SHIFT 
FARTHER N INTO N PORTIONS TONIGHT THROUGH EARLY MONDAY.

...TROPICAL WAVES... 

A TROPICAL WAVE IS INVOF 101W MOVING W 10-15 KT. ISOLATED 
MODERATE CONVECTION DOTS THE WATERS BETWEEN 100W AND 107W.
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            

THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 08.5N75W TO 07N88W 
TO 09.5N117W WHERE IT REMAINS FRACTURED...THEN RESUMES FROM 
19N116W TO LOW PRES NEAR 17.5N117.0W TO 11.5N127W TO 12N134W TO 
BEYOND 10N140W. SCATTERED MODERATE TO STRONG WITHIN 120 NM N AND 
270 NM S OF TROUGH BETWEEN 102W AND 117W. SCATTERED MODERATE TO 
STRONG WITHIN 90 NM NW AND N...AND WITHIN 210 NM S AND SE OF 
TROUGH BETWEEN 116W AND 140W. 
 
...DISCUSSION...

A 1026 MB HIGH CENTERED NW OF THE AREA NEAR 37N151W EXTENDS A 
RIDGE SE TO JUST SW OF T.D. SIXTEEN-E...NEAR 22N118W. THE PRES 
GRADIENT BETWEEN THE RIDGE AND MONSOON TROUGH IS PRODUCING 
MODERATE TO FRESH NE TRADE WINDS OVER WESTERN PORTIONS OF THE 
AREA W OR 127W. THIS IS RESULTING IN SEAS TO 8 FT FROM FROM 12N 
TO 17N W OF 132W. THE HIGH PRES CENTER WILL SHIFT WESTWARD OVER 
THE NEXT 24 HOURS...WHICH WILL WEAKEN THE PRES GRADIENT OVER THE 
WESTERN WATERS AND RESULT IN DIMINISHED TRADE WINDS...WITH  
ASSOCIATED SEAS SUBSIDING TO BELOW 8 FT BY MONDAY.
 
GAP WINDS...A PULSING OF WINDS WILL START LATE TONIGHT ACROSS 
THE GULF OF TEHUANTEPEC. WINDS WILL PEAK DURING THE OVERNIGHT 
AND EARLY MORNING HOURS NEAR 25 KT TONIGHT AND NEAR 30 KT MON 
NIGHT. WINDS WILL BE WEAKEST IN THE AFTERNOON AND EARLY EVENING 
HOURS WITH WINDS MAINLY IN THE 20 KT RANGE...WITH LOCALLY 
STRONGER WINDS TO NEAR 25 KT. 
 
$$
STRIPLING