000
AXPZ20 KNHC 201505
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1605 UTC SUN SEP 20 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 
1500 UTC.               

...SPECIAL FEATURES...

AN ELONGATED AREA OF LOW PRES IS CENTERED NEAR 23N113W. 
SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED FROM 22N TO 
26N BETWEEN 112W AND 115W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WAS ALSO FROM 23N TO 29N BETWEEN 107W AND 112W. THERE 
REMAINS THE POTENTIAL FOR THIS LOW TO DEVELOP INTO A TROPICAL 
DEPRESSION TODAY AS IT MOVES IN A N-NW DIRECTION...THEN WILL 
MOVE ACROSS PORTIONS OF BAJA THIS EVENING AND MON AND CONDITIONS 
WILL BECOME UNFAVORABLE FOR DEVELOPMENT.

SW MONSOONAL FLOW WILL CONTINUE TO ADVECT ABUNDANT TROPICAL 
MOISTURE ACROSS SOUTHERN BAJA CALIFORNIA AND INTO CENTRAL 
PORTIONS AS WELL AS THE ADJACENT GULF AND MEXICAN STATES TO THE 
E TODAY. THIS TROPICAL MOISTURE WILL THEN SPREAD FARTHER NW-N 
ACROSS NORTHERN BAJA CALIFORNIA...AND MAY REACH FAR SOUTHERN 
CALIFORNIA MON INTO TUE. INCREASING RAIN CHANCES SHOULD BE 
EXPECTED ACROSS THESE AREAS...EXTENDING INLAND ACROSS MAINLAND 
MEXICO TO THE W SLOPES OF THE SIERRA MADRES OCCIDENTALES...WITH 
THE POTENTIAL FOR HEAVY RAINS...FLASH FLOODING AND LANDSLIDES. 

...TROPICAL WAVES... 

A TROPICAL WAVE AXIS IS NEAR 100W FROM 05N TO 17N. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WAS NOTED FROM 06N TO 10N 
BETWEEN 99W AND 102W. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            

THE MONSOON TROUGH EXTENDS FROM 08N78W TO 09.5N96W WHERE IT 
REMAINS FRACTURED. IT RESUMES FROM LOW PRES NEAR 15N117W TO 
10N130W TO 10N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WAS NOTED WITHIN 120 NM S OF TROUGH BETWEEN 81W AND 
87W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS 
NOTED WITHIN 120 NM OF TROUGH BETWEEN 120W AND 130W. 
 
...DISCUSSION...

HIGH PRESSURE OF 1026 MB CENTERED NW OF THE AREA NEAR 36N148W 
EXTENDS A RIDGE SE TO NEAR 23N125W. THE PRES GRADIENT BETWEEN 
THE RIDGE AND MONSOON TROUGH IS PRODUCING MODERATE TO FRESH NE 
TRADE WINDS OVER MOST OF THE WESTERN PORTION. THIS IS RESULTING 
IN SEAS TO 8 FT FROM FROM 15N TO 22N W OF 135W. THE HIGH PRES 
CENTER WILL SHIFT WESTWARD OVER THE NEXT 24 HOURS. THIS WILL 
WEAKEN THE PRES GRADIENT OVER THE WESTERN WATERS WHICH WILL 
RESULT IN DIMINISHED TRADE WINDS AND ASSOCIATED SEAS 
SUBSIDING TO BELOW 8 FT BY MONDAY.
 
GAP WINDS...A PULSING OF WINDS WILL START LATE TONIGHT IN 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 NEAR 25 KT. 
 
$$
AL