000
AXPZ20 KNHC 231533
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 UTC TUE JUL 23 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...SPECIAL FEATURES...                                          
A 1007 MB SURFACE LOW IS CENTERED NEAR 12N112W MOVING WESTWARD 
AT 15 KT AND REMAINS LARGELY EMBEDDED WITHIN THE MONSOON TROUGH 
AXIS. CONVECTIVELY...THE LOW HAS MAINTAINED ORGANIZATION OVER 
THE PAST 6 TO 12 HOURS HOWEVER...THE SURFACE LOW APPEARS 
ELONGATED ALONG AN AXIS FROM 17N110W TO 11N117W. CONVECTION IS 
SPLIT BETWEEN A NORTHERN BAND OF SCATTERED MODERATE AND ISOLATED 
STRONG CONVECTION FROM 12N-17N BETWEEN 112W-118W AND A SOUTHERN 
BAND OF SCATTERED MODERATE CONVECTION FROM 05N-12N BETWEEN 113W-
122W. THE LOW IS FORECAST TO TRACK W-NW OVER THE NEXT SEVERAL 
DAYS AND HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE 
DURING THE NEXT 48 HOURS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
THE MONSOON TROUGH EXTENDS FROM 08N78W TO 09N95W TO LOW PRES 
NEAR 12N114W TO 10N120W TO 11N127W TO 10N140W. SCATTERED 
MODERATE CONVECTION IS FROM 11N TO 16N BETWEEN 93W AND 98W...AND 
FROM 09N TO 13N BETWEEN 99W AND 104W. WIDELY SCATTERED MODERATE 
CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE AXIS BETWEEN 124W 
AND 140W.

...DISCUSSION...                                                
A NEARLY STATIONARY 1026 MB HIGH PRESSURE LOCATED N OF THE AREA 
NEAR 40N142W EXTENDS A SURFACE RIDGE SOUTHWESTWARD INFLUENCING 
THE NW PORTION OF THE FORECAST REGION N OF 20N W OF 130W. A VERY 
WEAK PRESSURE GRADIENT DOMINATES THE REMAINDER OF THE NORTH 
WATERS...PARTICULARLY N OF 20N E OF 130W. A WEAK TROUGH IS 
ANALYZED FROM 25N128W TO 31N126W. THE MOST RECENT SCATTEROMETER 
PASSES SHOWED VARIABLE WINDS OF 5-10 KT ACROSS THAT AREA. TRADE 
WINDS IN THE RANGE OF 10-20 KT ARE NOTED S OF THE RIDGE AND N OF 
THE MONSOON TROUGH W OF 120W.
 
GAP WINDS OF 15-20 KT CONTINUE ACROSS THE GULF OF PAPAGAYO AND 
AREAS TO THE WEST AS FRESH TO STRONG TRADE WIND FLOW IN THE SW 
CARIBBEAN FUNNELS THROUGH THE GAP. THE WINDS ARE GREATEST DURING 
THE OVERNIGHT AND EARLY MORNING HOURS WITH THE ASSISTANCE OF THE 
NOCTURNAL DRAINAGE FLOW.

CROSS EQUATORIAL S AND SW SWELLS WITH PERIODS IN THE 17 TO 20 
SECONDS RANGE ARE PROPAGATING TOWARDS THE SOUTHERN MEXICO AND 
CENTRAL AMERICAN COAST THIS MORNING AND AFTERNOON. THESE SWELLS 
ARE EXPECTED TO LOWER INTO THE 14 TO 16 SECONDS RANGE BY EARLY 
THURSDAY.

$$
HUFFMAN