000
AXPZ20 KNHC 231521
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1605 UTC TUE APR 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.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...              
THE MONSOON TROUGH AXIS EXTENDS FROM 04N77W TO 05N83W TO 07N87W. 
THE ITCZ AXIS CONTINUES FROM 07N87W TO 08N108W TO 04N125W TO 
BEYOND 06N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
FROM 02N TO 05N BETWEEN 92W AND 96W...AND FROM 03N TO 10N 
BETWEEN 100W AND 112W. SIMILAR CONVECTION IS ALSO NOTED FROM 10N 
TO 13N BETWEEN 102W AND 118W...WITHIN 210 NM N OF AXIS BETWEEN 
127W AND 135W...AND WITHIN 90 NM S OF AXIS W OF 138W.

...DISCUSSION... 

AS IT IS NORMAL FOR THIS TIME OF THE YEAR...THE NORTHEASTERN 
PACIFIC IS RELATIVELY QUIET. THERE ARE NO GALES...NO GAP WINDS 
EVENTS AND NO ACTIVE COLD FRONTS. MODEL GUIDANCE SHOWS VERY 
LITTLE SIGNIFICANT CHANGE ON THE SHORT-TERM HORIZON. 

WINDS ARE EXPECTED TO REMAIN BELOW 25 KT OVER THE ENTIRE 
FORECAST AREA THROUGH AT LEAST THU MORNING...BUT N WINDS WELL 
OFF THE CALIFORNIA COAST N OF THE AREA SHOULD BECOME STRONG 
ENOUGH TO PROPAGATE N SWELL WITH 8-9 FT SEAS INTO WATERS N OF 
29N W OF 130W WED EVENING THROUGH THU MORNING. 

A 1036 MB HIGH PRES LOCATED WELL N OF THE AREA NEAR 48N135W 
EXTENDS A RIDGE SOUTHWARD INTO THE NORTHERN FORECAST WATERS.   
AN AREA OF MODERATE TO FRESH NE TRADE WINDS IS NOTED PER THE 
MOST RECENT SCATTEROMETER DATA ON THE SOUTHERN PERIPHERY OF THE 
RIDGE AND N OF THE ITCZ AXIS...PARTICULARLY FROM 07N TO 16N W OF 
130W.

A WEAK 1010 MB LOW PRES IS ANALYZED ALONG THE ITCZ AXIS NEAR 
07N112W WHERE THE SURROUNDING CONVECTION APPEARS MORE 
CONCENTRATED. THIS FEATURE WILL MOVE WESTWARD OVER THE NEXT 
COUPLE OF DAYS.
                                             
ALOFT...A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE N WATERS WITH 
A CUT-OFF LOW SPINNING NEAR 32N130W. THE SURFACE REFLECTION OF 
THIS LOW AND RESULTANT TROUGHING WILL WEAKEN THE SUBTROPICAL 
RIDGE OVER N WATERS...KEEPING WINDS THERE LIGHT. AN UPPER RIDGE 
AXIS EXTENDS FROM COLOMBIA ALL THE WAY NORTHWESTWARD ACROSS 
CENTRAL AMERICA AND MEXICO. THIS RIDGE IS HELPING TO ENHANCE 
CONVECTION ACROSS THE MONSOON TROUGH AND ITCZ AXIS. UPPER 
DIFFLUENCE IS MOST VIGOROUS NEAR A TROUGH THAT EXTENDS FROM 
20N118W TO 10N111W TO 07N109W. CONVECTION HAS INCREASED MAINLY 
ON THE WEST SIDE OF THE TROUGH AXIS.  THE SURFACE REFLECTION OF 
THIS LOW AND RESULTANT TROUGHING WILL WEAKEN THE SUBTROPICAL 
RIDGE OVER NE WATERS...KEEPING WINDS THERE LIGHT.

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

$$
GR