000
AXPZ20 KNHC 191001
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC SAT SEP 19 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.               

...SPECIAL FEATURES...

AN ELONGATED AREA OF LOW PRES EXTENDS FROM A FEW HUNDRED MILES S 
OFF THE SOUTHERN TIP OF CALIFORNIA...SOUTHWESTWARD INTO THE 
TROPICS...WITH A PAIR OF LOW PRESSURE CENTERS EMBEDDED NEAR EACH 
END...ONE LOCATED NEAR 17.5N113W AND THE OTHER NEAR 15N119W. 
SATELLITE IMAGERY IS SHOWING INCREASING CLUSTERS OF SCATTERED 
STRONG CONVECTION WITHIN 120 NM OF THE LOW IN THE NW QUADRANT. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 45 NM OF
21N113W...AND ALSO WITHIN 30 NM OF 18N116W. AN ASCAT PASS FROM 
0448 UTC LAST NIGHT SHOWED WINDS GENERALLY IN THE 15-20 KT RANGE 
SURROUNDING THIS ELONGATED CIRCULATION...AND ALSO REVEALED 
SIMILAR WITH THE LOW PRES NEAR 15N119W. THE EASTERN PERIPHERY OF 
THE ASCAT PASS DEPICTED THE FAR EASTERN EXTENT OF THE CYCLONIC 
CIRCULATION REACHING TO NEAR 105W.

GLOBAL MODELS CONTINUE TO INDICATE THAT THIS ELONGATED AREA OF 
LOW PRES WILL CONTINUE TO ADVECT ABUNDANT TROPICAL MOISTURE 
TOWARDS CENTRAL AND SOUTHERN BAJA CALIFORNIA AS WELL AS THE 
ADJACENT GULF AND MEXICAN STATES TO THE E. THE MOISTURE SHOULD 
THEN SPREAD FARTHER NW-N ACROSS NORTHERN BAJA CALIFORNIA SAT AND 
SAT NIGHT AS THE ELONGATED LOW PRES AREA BEGINS TO SHIFT N-NW. 
SOME OF THIS MOISTURE SHOULD REACH FAR SOUTHERN CALIFORNIA SUN 
INTO MON. 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 THROUGH THE 
WEEKEND. THERE IS SOME POTENTIAL FOR THE EASTERN MOST LOW TO 
IMPROVE IN ORGANIZATION THROUGH THE NEXT 48 HOURS...AND THIS 
SYSTEM HAS A MEDIUM CHANCE FOR DEVELOPMENT INTO A TROPICAL 
CYCLONE AS IT MOVES IN A N-NW DIRECTION.

...TROPICAL WAVES... 

A TROPICAL WAVE AXIS IS ALONG 90W N OF 09N TO ACROSS GUATEMALA 
AND TO THE SOUTHERN YUCATAN PENINSULA AREA. IT IS MOVING W 15-20 
KT. SCATTERED MODERATE CONVECTION IS SEEN WITHIN 30 NM OF 14N91W.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            

THE MONSOON TROUGH AXIS EXTENDS FROM COLOMBIA NEAR 09N73W TO 
09N83W TO 08N91W TO 08N98W TO 10N107.5W WHERE IT HAS FRACTURED. 
IT RESUMES FROM LOW PRES NEAR 18N112W TO LOW PRES NEAR 15N119W 
TO 12N128W TO BEYOND 11.5N140W. SCATTERED MODERATE TO STRONG 
CONVECTION IS FROM 07N-10N E OF 83W. SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION EXISTS FROM 04N-10N BETWEEN 103W-107W...AND 
WITHIN 60 NM S OF TROUGH W OF 138W. SCATTERED MODERATE 
CONVECTION IS WITHIN 180 NM S OF THE TROUGH BETWEEN 91W-94W.
 
...DISCUSSION...

WELL TO THE NW OF THE ELONGATED AREA OF LOW PRES...A 1023 MB 
HIGH PRES CENTER IS ANALYZED N OF THE HAWAIIAN ISLANDS NEAR 
35N149W WITH A RIDGE EXTENDING E THEN SE TO NEAR 22N115W. THE 
PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES IN THE TROPICS IS 
RESULTING IN FRESH TO STRONG NE TRADE WINDS WITHIN 150 NM NW OF 
A LINE FROM 19N140W TO 20N130W...WHERE SEAS ARE IN THE RANGE OF 
7-9 FT. THIS AREA OF FRESH TO STRONG NE TRADE WINDS IS FORECAST 
TO SHRINK IN COVERAGE AS IT SHIFTS W THROUGH SUN. THE RIDGE WILL 
SHIFT SLIGHTLY EWD DURING THE NEXT 48 HOURS...WHILE THE 
ELONGATED LOW PRES REALIGNS NE TO SW...WHICH WILL ACT TO 
DIMINISH THESE TRADES SLIGHTLY.
 
TO THE E OF THE RIDGE...NWLY WINDS OF 10-15 KT WERE DEPICTED BY 
AFTERNOON SCATTEROMETER DATA...WHERE SEAS ARE GENERALLY 
GENERALLY 4-5 FT IN MIXED SW AND NW SWELL. THE EASTERN PORTION 
OF THE RIDGE WILL WEAKEN SLIGHTLY OVER THE NEXT FEW DAYS...AS 
THE N PORTION OF THE ELONGATED LOW PRES AREA LIFTS N OF 
20N...PRODUCING WEAKENING WINDS ALONG THE WATERS W OF BAJA 
CALIFORNIA. HOWEVER...INCREASING WINDS ACROSS THE OFFSHORE 
WATERS OF CALIFORNIA WILL GENERATE A NEW PULSE OF N-NW SWELL 
THAT WILL MOVE INTO NE PORTIONS OF THE DISCUSSION AREA OVER THE 
WEEKEND AND RAISE SEA HEIGHTS TO 6-8 FT...MAINLY W OF 118W. 
OTHERWISE...SEAS WILL CONTINUE TO BE DOMINATED BY PULSES OF 
MODERATE SW SOUTHERN HEMISPHERIC SWELL.
  
$$
AGUIRRE