000
AXPZ20 KNHC 240227
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
0405 UTC WED JUL 24 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0230 UTC.

...SPECIAL FEATURES...                                          

A 1007 MB SURFACE LOW IS CENTERED NEAR 12.5N117W MOVING WESTWARD 
AT 13 KT AND REMAINS LARGELY EMBEDDED WITHIN THE MONSOON TROUGH 
AXIS. CONVECTIVELY...THE LOW HAS NOT BECOME ANY BETTER ORGANIZED 
DURING THE PAST SEVERAL HOURS...AND IT APPEARS ELONGATED ALONG 
AN AXIS FROM 16N114W TO 10N118W. NUMEROUS MODERATE AND SCATTERED 
STRONG CONVECTION IS WITHIN 240 NM IN THE N AND NE QUADRANTS. 
SCATTERED MODERATE CONVECTION IS ELSEWHERE WITHIN 270 NM OF 
CENTER. 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 AXIS EXTENDS FROM 08N78W TO 10N100W TO LOW 
PRES NEAR 12.5N117W TO 10N121W TO 10N140W. NO ITCZ AXIS IS 
PRESENT. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM EITHER 
SIDE OF A LINE 13N103W TO 07N107W...WITHIN 90 NM N OF THE 
MONSOON TROUGH BETWEEN 110W AND 113W...FROM 07N TO 10N BETWEEN 
120W AND 127W...AND ALSO WITHIN 120 NM EITHER SIDE OF THE 
MONSOON TROUGH BETWEEN 128W AND 137W. 

...DISCUSSION...                                                

A NEARLY STATIONARY 1026 MB HIGH PRESSURE CENTER IS LOCATED WELL 
N OF THE DISCUSSION AREA NEAR 41N142W. A SURFACE RIDGE EXTENDING 
SOUTHEASTWARD IS INFLUENCING THE NW PORTION OF THE FORECAST 
REGION N OF 20N W OF 130W. A VERY WEAK PRESSURE GRADIENT 
DOMINATES THE REMAINDER OF THE N WATERS...PARTICULARLY N OF 20N 
E OF 130W. A WEAK SURFACE TROUGH IS ANALYZED FROM 25N127W TO 
31N126W. THE MOST RECENT SCATTEROMETER PASSES SHOWED VARIABLE 
WINDS OF 5 TO 10 KT ACROSS THAT AREA. TRADE WINDS IN THE RANGE 
OF 10 TO 20 KT ARE NOTED S OF THE RIDGE AND N OF THE MONSOON 
TROUGH W OF 120W.

GAP WINDS OF 15 TO 20 KT CONTINUE ACROSS THE GULF OF PAPAGAYO 
AND AREAS TO THE W AS FRESH TO STRONG TRADE WIND FLOW IN THE SW 
CARIBBEAN SEA FUNNELS THROUGH THE GAP. THE WINDS ARE GREATEST 
DURING THE OVERNIGHT AND EARLY MORNING HOURS WITH THE ASSISTANCE 
OF THE NOCTURNAL DRAINAGE FLOW. THESE WINDS WILL INCREASE TO 20-
25 KT BY EARLY THU MORNING DOWNWIND TO 90W WHICH WILL BUILD SEAS 
TO 8 FT...THEN WILL DIMINISH BY THU EVENING.

CROSS EQUATORIAL S AND SW SWELLS WITH PERIODS IN THE 16 TO 18 
SECONDS RANGE ARE PROPAGATING TOWARDS THE SOUTHERN MEXICO AND 
CENTRAL AMERICAN COAST THIS EVENING. WITH SUCH LONG PERIODS 
THERE IS A THREAT FOR RIP CURRENTS AT COASTAL LOCATIONS THROUGH 
WED. THESE PERIODS ARE EXPECTED TO LOWER INTO THE 13 TO 15 
SECONDS RANGE BY EARLY THU. 

BY THU AFTERNOON INTO EVENING...A REINFORCING PUSH OF 8 FT 
SOUTHERLY SWELL WILL BREACH THE EQUATOR REACHING TO 02N BETWEEN 
110W AND 120W BY THU AFTERNOON.

$$
LEWITSKY