000
AXPZ20 KNHC 280916
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED AUG 28 2013

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...

LOW PRES OF 1006 MB IS CENTERED NEAR 18N106W. A GALE WARNING IS 
IN EFFECT WITHIN 120 NM E SEMICIRCLE. THERE IS A MEDIUM CHANCE 
THAT THE LOW MAY DEVELOP INTO A TROPICAL CYCLONE WITHIN THE NEXT 
48 HOURS. REGARDLESS OF DEVELOPMENT...THE SYSTEM WILL CONTINUE 
TO PRODUCE GALE FORCE WINDS...ESPECIALLY OVER THE EASTERN 
SEMICIRCLE...OVER THE NEXT 36 HOURS. CURRENTLY... ACTIVE 
CONVECTION IS NOTED ACROSS FROM 12N-19N BETWEEN 104W-107W. 
LOCALLY HEAVY RAINFALL IS POSSIBLE OVER PORTIONS OF SOUTHWESTERN 
MEXICO AND THE SOUTHERN BAJA PENINSULA OVER THE NEXT FEW DAYS IN 
ASSOCIATION WITH THIS AREA OF LOW PRESSURE. INTERESTS IN THAT 
AREA SHOULD MONITOR THE PROGRESS OF THIS SYSTEM.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

MONSOON TROUGH FROM 11N86W TO 13N93W THEN RESUMES TO LOW PRES 
NEAR 13N110W 1006 MB TO 1011 MB LOW PRES NEAR 13N131W TO 
11N140W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 100 NM 
EITHER SIDE OF AXIS FROM 87W-93W AND FROM 12N-16N BETWEEN 110W 
AND WITHIN 180 NM S OF AXIS FROM 110W-121W AND WITHIN 90 NM 
EITHER SIDE OF AXIS FROM 129W TO 136W.

...DISCUSSION...

UPPER LEVEL TROUGH ACROSS THE FAR NW PORTION OF THE DISCUSSION 
AREA EXTENDS FROM 32N135W TO 28N14W. SW UPPER LEVEL WINDS IN THE 
40-55 KT RANGE ARE SE OF THE TROUGH AXIS FROM 25N140W TO 
32N136W. UPPER LEVEL RIDGE EXTENDS FROM AN ANTICYCLONIC 
CIRCULATION JUST OFF THE BAJA CALIFORNIA COAST CENTERED NEAR 
28N115W TO ANOTHER ANTICYCLONIC CIRCULATION NEAR 18N130W. 
MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR AT THE MIDDLE 
AND UPPER LEVELS IS N OF 18N W OF 115W. UPPER LEVEL DIFFLUENT 
FLOW IS ENHANCING CONVECTION ALONG THE MONSOON TROUGH.

MAIN FEATURE OF CONCERN W OF 100W IS THE VERY ACTIVE MONSOON 
TROUGH. AS IS TYPICAL WITH A MONSOON TROUGH...THE MAJORITY OF 
THE RAINFALL IS S OF THE MONSOON TROUGH. THE RAINFALL IN THIS 
CASE IS ASSOCIATED WITH THE CONVERGENCE OF MOIST 20 TO 25 KT SW 
MONSOONAL FLOW. THERE ARE SEVERAL EMBEDDED LOW PRES AREAS WITHIN 
THE MONSOON TROUGH. THE FIRST LOW IS THE DESCRIBED ABOVE IN THE 
SPECIAL FEATURES SECTION ANOTHER WEAK LOW IS NEAR 13N110W WITH A 
THIRD NEAR 11N121W AND ANOTHER LOW NEAR 15N131W

$$
DGS