000
AXPZ20 KNHC 232127
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURES...                                          

A 1007 MB SURFACE LOW IS CENTERED NEAR 12N115.5W MOVING WESTWARD 
AT 15 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 16N113W TO 11N116W. CONVECTION REMAINS SPLIT 
BETWEEN A SOUTHERN BAND OF SCATTERED MODERATE CONVECTION FROM 
07N TO 11N BETWEEN 115W AND 120W. THE NORTHERN PORTION OF 
CONVECTION HAS CONSOLIDATED SLIGHTLY WITH SCATTERED MODERATE TO 
STRONG FROM 11N TO 17N BETWEEN 113W AND 119W. 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 12N115.5W TO 10N121W TO 10N140W. NO ITCZ AXIS IS 
PRESENT. SCATTERED MODERATE CONVECTION IS FROM 10N TO 14N 
BETWEEN 94W AND 105W...FROM 10N TO 14N BETWEEN 108W AND 
110W...WITHIN 270 NM S OF THE MONSOON TROUGH BETWEEN 120W AND 
126W...AND ALSO WITHIN 90-120 NM EITHER SIDE OF THE MONSOON 
TROUGH BETWEEN 128W AND 136W. 

...DISCUSSION...                                                

A NEARLY STATIONARY 1026 MB HIGH PRESSURE CENTER IS LOCATED WELL 
N OF THE DISCUSSION AREA NEAR 42N140. 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 24N127W TO 
32N126W. 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. THESE WINDS WILL INCREASE TO 20-25 KT 
BY EARLY THU MORNING DOWNWIND TO 90W WHICH WILL BUILD SEAS TO 8 
FT.

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 AFTERNOON. WITH SUCH LONG PERIODS 
THERE IS A THREAT FOR RIP CURRENTS AT COASTAL LOCATIONS THROUGH 
WED. THESE SWELLS ARE EXPECTED TO LOWER INTO THE 13 TO 15 
SECONDS RANGE BY EARLY THURSDAY. 

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

$$
LEWITSKY