000
AXPZ20 KNHC 091004
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC THU APR 09 2015

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY  
THROUGH 0900 UTC. 
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
          
THE ITCZ IS ALONG 02N94W 04N126W 03N125W 04N140W. CONVECTIVE 
PRECIPITATION...NUMEROUS STRONG WITHIN 60 NM ON EITHER SIDE OF 
THE ITCZ BETWEEN 105W AND 107W...WITHIN 30 NM ON EITHER SIDE OF 
THE ITCZ BETWEEN 128W AND 130W...AND WITHIN 45 NM ON EITHER SIDE 
OF THE LINE FROM 06N133W TO 05N134W TO 04N136W TO 04N137W. 
SCATTERED MODERATE ISOLATED STRONG WITHIN 210 NM TO THE NORTH OF 
THE ITCZ BETWEEN 94W AND 104W...FROM 02N TO 07N BETWEEN 121W AND 
127W...AND FROM 03S TO 04S WITHIN 30 NM ON EITHER SIDE OF 90W.

...DISCUSSION... 

A SURFACE RIDGE EXTENDS FROM A 1022 MB HIGH PRESSURE CENTER THAT 
IS NEAR 32N125W...TO 24N123W TO 16N118W TO 09N119W.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH...THAT IS ALONG 135W...IS 
SPREADING CYCLONIC WIND FLOW FROM 17N NORTHWARD FROM 117W 
WESTWARD. A COLD FRONT IS IN THE FAR NORTHWESTERN CORNER OF THE 
AREA...PASSING THROUGH 32N138W BEYOND 30N140W. 

AN UPPER LEVEL RIDGE IS ALONG 08N126W 13N116W...TO 17N104W.AN 
UPPER LEVEL TROUGH PASSES THROUGH THE GULF OF HONDURAS INTO THE 
EASTERN PACIFIC OCEAN NEAR 12N90W...TO 04N92W. 

THE SUBTROPICAL HIGH IS EXPECTED TO WEAKEN FURTHER AND SHIFT SE 
AS A PROGRESSIVE COLD FRONT NW OF THE AREA ENCROACHES UPON IT. 
THIS SHOULD KEEP TRADE WINDS BELOW THE ADVISORY CRITERIA OF 20-
25 KT THROUGH THE END OF THE FORECAST PERIOD FRIDAY AFTERNOON. 
WINDS SHOULD REMAIN A SOLID FRESH BREEZE IN THE MAIN TRADE WIND 
BELT N OF THE ITCZ AND HELP MAINTAIN SEAS TO 9 FT OVER WATERS W 
OF 120W THROUGH EARLY FRI WHERE NW...NE AND SW SWELL ARE 
COMBINING. SEAS ARE EXPECTED TO DIMINISH BELOW 8 FT BY FRI 
EVENING.

THE COLD FRONT ENCROACHING ON THE SUBTROPICAL HIGH IS FORECAST 
TO REACH THE NW FORECAST WATERS THU. SW WINDS TO ADVISORY 
CRITERIA ARE EXPECTED WITHIN 90 NM AHEAD OF THE FRONT. SEAS WILL 
SLOWLY BUILD ABOVE 8 FT BEHIND THE FRONT OVERNIGHT THU NIGHT. 
ALOFT...THE TROUGH SUPPORTING THIS COLD FRONT IS EXPECTED TO CUT 
OFF FROM THE NORTHERN STREAM BY THU NIGHT. A DEEP LAYERED LOW 
WILL MOVE INTO WATERS N OF 30N BETWEEN 130W-135W ON FRI. WINDS W 
OF THE LOW WILL INCREASE TO A STRONG BREEZE AS SEAS BUILD AS 
HIGH AS 15 FT. 

GAP WINDS...                                                    
THE GULF OF PAPAGAYO...NE WINDS 20 TO 25 KNOTS AND 8 TO 9 FOOT 
SEA HEIGHTS WILL BE PRESENT FOR THE FIRST 12 HOURS OF THE 48-
HOUR FORECAST PERIOD...AND THEN WEAKEN TO 20 KNOTS OR LESS WITH 
SEA HEIGHTS LOWER THAN 8 FEET DURING THE NEXT 12 HOURS.  THE 20 
TO 25 KNOTS AND 8 TO 9 FOOT SEA HEIGHTS WILL RETURN DURING THE 
EARLY MORNING HOURS OF FRIDAY...AND CONTINUE FOR THE NEXT 12 
HOURS OR SO...BEFORE WEAKENING AGAIN TO LOWER THAN THE THRESHOLD 
LEVELS FOR THE NEXT 12 HOURS.
 
THE GULF OF CALIFORNIA... NW WINDS 20 TO 25 KNOTS AND SEA 
HEIGHTS LOWER THAN 8 FEET WILL START LATE IN THE PERIOD...AT THE 
42-HOUR MARK...AND THOSE CONDITIONS WILL CONTINUE UNTIL THE END 
OF THE 48-HOUR FORECAST PERIOD TIME.

$$
MT