000
AXPZ20 KNHC 242209
TWDEP 

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

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
 
MONSOON TROUGH AXIS EXTENDS FROM COLOMBIA NEAR 08N74W TO 
02.5N77.5W TO 07.5N88W...WHERE IT TRANSITIONS TO ITCZ... 
CONTINUING ON TO 06N97W TO 09N110W TO BEYOND 03N140W. SCATTERED 
MODERATE TO STRONG CONVECTION NOTED WITHIN 120 NM S AND 210 NM N 
OF ITCZ BETWEEN 88W AND 123W. ISOLATED TO SCATTERED MODERATE 
CONVECTION NOTED WITHIN 120 NM EITHER SIDE OF ITCZ W OF 127W.
       
...DISCUSSION... 

RELATIVELY QUIET CONDITIONS PERSIST ACROSS THE DISCUSSION AREA 
THIS AFTERNOON. 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. HOWEVER...BY 24 HOURS...HIGH PRES BUILDING ACROSS THE SE 
U.S. BEHIND A LATE SEASON GULF OF MEXICO COLD FRONT IS EXPECTED 
TO INDUCE A LATE SEASON GULF OF TEHUANTEPEC GAP WIND EVENT. 
PRESENTLY...GLOBAL MODELS INDICATE NORTHERLY WINDS OF 20-25 KT 
WILL BEGIN TO SPILL THROUGH THE CHIVELA PASS BY THURSDAY 
AFTERNOON...AND INCREASE TO 20-30 KT BY LATE THURSDAY NIGHT INTO 
FRI MORNING. HOWEVER...WINDS MAY BRIEFLY REACH NEAR GALE FORCE 
WINDS EARLY FRI WITH THE ASSISTANCE OF THE NOCTURNAL DRAINAGE 
FLOW. SIMILARLY...THE NOCTURNAL DRAINAGE FLOW WILL AID FRESH 
WINDS ACROSS THE GULF OF PAPAGAYO OVER THE NEXT COUPLE OF DAYS. 
LOOKING AHEAD...GLOBAL MODEL GUIDANCE SUGGESTS INCREASING WINDS 
TO 20-25 KT ACROSS THE GULF OF PAPAGAYO BY EARLY FRI AND SAT 
MORNINGS. 

OTHERWISE...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 N OF 28N BETWEEN 130W AND 139W AND SHIFTING SLIGHTLY 
SW THROUGH THU. THESE SEAS SHOULD SUBSIDE BY THURSDAY EVENING. 

HIGH PRES REMAINS GENERALLY BLOCKED FROM THE LOCAL AREA...WHICH 
IS LIMITING THE STRENGTH OF THE TRADE WINDS. A 1034 MB HIGH IS 
LOCATED WELL N OF THE FORECAST AREA NEAR 48N137W AND EXTENDS A 
RIDGE S INTO THE DISCUSSION AREA W OF 130W. THIS SUBTROPICAL 
RIDGE IS BEING DISRUPTED BY DEEP LAYERED CUT OFF LOW PERSISTING 
OFFSHORE OF SOUTHERN CALIFORNIA...THAT HAS SHIFTED NE TOWARDS 
THE COAST TODAY. AN ASSOCIATED 1011 MB SURFACE LOW IS LOCATED 
NEAR 31N122W AND DRAGS A WEAK AND BENIGN FRONTAL TROUGH SW TO 
23N130W. WITHIN THE NEXT 48 HOURS...THE LOW IS EXPECTED TO 
WEAKEN TO A TROUGH AS THE SUPPORTING CUT OFF LOW CONTINUES TO 
MOVE EASTWARD AND INLAND. AS THIS OCCURS...THE SUBTROPICAL RIDGE 
WILL BUILD IN 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 32N121W SHIFTING SLOWLY NE. 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 
PRODUCING SMOKE THAT IS BEING TRANSPORTED WESTWARD INTO THE 
OFFSHORE WATERS. THESE CONDITIONS WILL LIKELY CONTINUE OVER THE 
NEXT FEW DAYS AS SEASONAL BURNING CONTINUES ACROSS THE REGION.

$$
STRIPLING