000
AXPZ20 KNHC 241521
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 UTC WED APR 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1430 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
            
MONSOON TROUGH AXIS EXTENDS FROM THE COAST OF COLOMBIA NEAR 
06N77W TO 08N89W TO 08N102W...WHERE IT TRANSITIONS TO 
ITCZ...CONTINUING ON TO 08N115W TO 05N130W TO 03N140W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 03N TO 07N 
BETWEEN 91W AND 100W. SIMILAR CONVECTION CAN BE FOUND FROM 06N 
TO 10N BETWEEN 100W AND 110W...FROM 05N TO 11N BETWEEN 110W AND 
120W AND WITHIN 120 NM S OF ITCZ AXIS W OF 136W.
        
...DISCUSSION... 

OTHER THAN A SMALL AREA OF LONG PERIOD NE SWELL ANALYZED N OF 
29N BETWEEN 130W AND 135W...THERE IS NOT MUCH HAPPENING IN THE  
NORTHEAST PACIFIC REGION. CURRENTLY...THERE ARE NO GALES...NO 
GAP WIND EVENTS AND NO ACTIVE COLD FRONTS ACROSS THE AREA. 
GLOBAL MODEL GUIDANCE SHOWS LITTLE SIGNIFICANT CHANGES DURING 
THE NEXT 24 HOURS. THIS WEATHER PATTERN IS EXPECTED TO CHANGE IN 
ABOUT 36 HOURS WITH A LATE SEASON GULF OF TEHUANTEPEC WIND EVENT 
WHICH WILL BE INDUCE BY A MODERATE TO STRONG HIGH PRES BUILDING 
SW ACROSS THE GULF OF MEXICO FROM THE MIDDLE ATLC STATES. 
NOW...THE FORECAST CALLS FOR WINDS REACHING 20-30 KT BY FRI 
MORNING BASED ON THE GFS GLOBAL MODEL AND THE NAM REGIONAL 
MODEL. HOWEVER...WINDS MAY BRIEFLY REACH NEAR GALE FORCE WINDS 
EARLY FRI WITH THE ASSISTANCE OF THE NOCTURNAL DRAINAGE FLOW. 
SIMILARLY...THE DRAINAGE FLOW WILL AID FRESH WINDS ACROSS THE 
GULF OF PAPAGAYO OVER THE NEXT COUPLE OF DAYS. LOOKING AHEAD... 
MARINE GUIDANCE SUGGESTS INCREASING WINDS TO 20-25 KT ACROSS THE 
GULF OF PAPAGAYO BY EARLY SAT MORNING. 

WINDS ARE EXPECTED TO REMAIN BELOW 25 KT OVER THE ENTIRE 
FORECAST AREA THROUGH LATE THU. HOWEVER...A BROAD AREA OF N TO 
NE WINDS OCCURRING WELL OFF THE CALIFORNIA COAST WILL BRING NE 
SWELL THAT WILL PROPAGATE INTO NE PORTIONS...RAISING SEAS TO 
AROUND 8 FT...AS PREVIOUSLY MENTIONED...N OF 30N BETWEEN 130W 
AND 135W AND SHIFTING SLIGHTLY W THROUGH THU. THESE SEAS SHOULD 
SUBSIDE BY THURSDAY EVENING.

A BURST OF STRONG CONVECTION DEVELOPED ABOUT 240 NM S-SW OF  
ACAPULCO OVERNIGHT. THIS CONVECTIVE ACTIVITY...SUPPORTED BY 
UPPER LEVEL DIVERGENCE AND MID-LEVEL VORTICITY...HAS MOVED NWD 
WHILE WEAKENING DUE STRONG WINDS ALOFT.  

A 1036 MB HIGH PRESSURE LOCATED WELL N OF THE FORECAST AREA NEAR 
48N137W EXTENDS A RIDGE S THEN SE OVER THE N WATERS TO NEAR 
20N112W. THIS SUBTROPICAL RIDGE IS BEING DISRUPTED BY DEEP 
LAYERED LOW OVER NE FORECAST WATERS. THE ASSOCIATED 1011 MB 
SURFACE LOW IS LOCATED NEAR 31N125W AND EXTENDS A SURFACE TROUGH 
INTO THE FORECAST AREA THROUGH 27N125W TO 24N128W. DUE TO THE 
PRESENCE OF THIS LOW...THE SUBTROPICAL RIDGE HAS WEAKENED OVER 
THE DISCUSSION AREA RESULTING IN TRADE WINDS LESS THAN 20 KT. 
THERE IS NO SIGNIFICANT CONVECTION ASSOCIATED TO THIS LOW. 
WITHIN THE NEXT 48 HOURS...THE LOW IS EXPECTED TO WEAKEN TO A 
TROUGH AS THE UPPER LOW THAT SUPPORTS THIS SYSTEM MOVES 
EASTWARD. THE SUBTROPICAL RIDGE WILL BUILD AGAIN ACROSS THE 
FORECAST WATERS BY SAT WITH AN INCREASE IN THE TRADE WINDS.

ALOFT...A RIDGE/TROUGH/RIDGE PATTERN CONTINUES TO DOMINATE THE N 
WATERS WITH A CUT-OFF LOW NEAR 31N124W SHIFTING SLOWLY E. AN 
UPPER RIDGE AXIS EXTENDS FROM COLOMBIA ALL THE WAY NORTHWESTWARD 
ACROSS CENTRAL AMERICA AND MEXICO. THIS RIDGE IS AIDING IN 
PROMOTING UPPER SPEED DIVERGENCE W OF THE RIDGE AXIS...WHICH IS 
HELPING TO MAINTAIN CONVECTION NEAR THE MONSOON TROUGH/ITCZ 
AXES. 

FIRES INLAND FROM SOUTHERN MEXICO INTO NORTHERN COSTA RICA ARE 
SENDING PATCHY SMOKE INTO OFFSHORE WATERS. THESE CONDITIONS WILL 
LIKELY CONTINUE OVER THE NEXT FEW DAYS.

$$
GR