000
AXPZ20 KNHC 280935
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI SEP 28 2012

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 
0900 UTC.

...SPECIAL FEATURES...

POST-TROPICAL REMNANT LOW MIRIAM IS NEAR 22N117W 1000 MB. 
ASSOCIATED WINDS ARE 20 TO 30 KT WITHIN 120 NM IN THE E 
SEMICIRCLE AND 180 NM IN THE W SEMICIRCLE OF MIRIAM WITH SEAS TO 
11 FT. NO DEEP CONVECTION IS PRESENT AND NO REGENERATION OF 
MIRIAM IS ANTICIPATED. MIRIAM WILL LINGER IN THE SAME GENERAL 
AREA THROUGH THE NEXT 24 HOURS WITH WINDS GRADUALLY DIMINISHING 
TO 20 TO 25 KT BY EARLY SAT MORNING...THEN TO 20 KT OR LESS BY 
EARLY SUN MORNING AS THE REMNANT LOW FURTHER DEGENERATES INTO A 
SURFACE TROUGH.

1005 MB LOW PRES IS NEAR 21N109W OR ABOUT 125 MILES SE OF THE 
SOUTHERN TIP OF THE BAJA CALIFORNIA PENINSULA. SCATTERED 
MODERATE TO STRONG CONVECTION IS WITHIN 210 NM IN THE N AND NE 
QUADRANTS...AND BETWEEN 90 AND 210 NM IN THE SE QUADRANT. WINDS 
OF 20 TO 30 KT ARE OCCURRING WITHIN 90 NM IN THE N AND S 
QUADRANTS OF THE LOW...EXCEPT WITHIN 240 NM IN THE SE QUADRANT 
OF THE LOW ALONG WITH SEAS TO 12 FT. RECENT SHIP OBSERVATIONS IN 
THE AREA WOULD IN INDICATE MUCH STRONGER WINDS ALTHOUGH THESE 
VESSELS HAVE ANEMOMETER HEIGHTS OF 25 TO 44 METERS ABOVE THE 
SURFACE SO HAVE DECIDED TO CONTINUE TO CAP WINDS BELOW GALE 
FORCE. THE LOW IS EXPECTED TO MOVE INLAND LATER TODAY OR 
TONIGHT...ALTHOUGH UNTIL THEN A TROPICAL CYCLONE COULD STILL 
FORM AND THE LOW HAS A MEDIUM CHANCE OF BECOMING A TROPICAL 
CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES NORTHWARD AT ABOUT 
10-15 KT. REGARDLESS OF ANY FURTHER DEVELOPMENT...LOCALLY HEAVY 
RAINS AND GUSTY WINDS ARE POSSIBLE ALONG PORTIONS OF THE WEST 
COAST OF MEXICO AND THE SOUTHERN BAJA PENINSULA DURING THE NEXT 
COUPLE OF DAYS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH IS ALONG 08N78W TO 10N88W TO LOW PRES NEAR 
09N99W 1010 MB TO 11N102W...THEN RESUMES FROM 17N108W TO 
11N126W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 
11N126W TO 10N140W. SCATTERED MODERATE TO STRONG CONVECTION IS N 
OF 12N BETWEEN 89W AND 94W. SCATTERED MODERATE CONVECTION IS 
FROM 11N TO 16N BETWEEN 105W AND 112W.

...DISCUSSION...

SUBTROPICAL 1023 MB HIGH PRES IS CENTERED JUST W OF THE AREA 
NEAR 32N144W WITH A RIDGE AXIS EXTENDING SE ACROSS THE NW WATERS 
TO NEAR 27N123W. MAINLY MODERATE TRADE WINDS ARE NOTED ON THE 
SOUTHERN PERIPHERY OF THE RIDGE E OF 140W AS SAMPLED BY RECENT 
SCATTEROMETER PASSES...ALONG WITH 5-7 FT SEAS.

FRESH TO STRONG SW MONSOONAL FLOW IS PRESENT S OF THE MONSOON 
TROUGH TO 09N BETWEEN 108W AND 125W AS CAPTURED BY A RECENT 
ASCAT PASS. SEAS OF 8-10 FT IN SW SWELL ARE ACCOMPANYING THESE 
WINDS. THESE CONDITIONS WILL PERSIST THROUGH THE NEXT 24 HOURS 
WITH WINDS DIMINISHING TO 20 KT OR LESS BY 48 HOURS. MEANWHILE 
AN AREA OF CROSS-EQUATORIAL SW SWELL TO 9 FT SURROUNDS THIS 
AREA...COVERING THE WATERS S OF 15N BETWEEN 105W AND 125W. THE 
SWELL WILL GRADUALLY DECAY TO LESS THAN 8 FT N OF 04N BY 24 
HOURS...THEN TO N OF 03N BY 48 HOURS.

A SET OF LONG PERIOD NW SWELL TO 9 FT WITH PEAK WAVE PERIODS OF 
13-15 SECONDS WILL INVADE THE FAR NW WATERS BEGINNING EARLY SAT 
MORNING...GRADUALLY PROPAGATING TO THE SE THROUGH THE WEEKEND.   

$$
LEWITSKY