000 AXPZ20 KNHC 221539 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC WED APR 22 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1430 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A MONSOONAL CIRCULATION IS NOT YET PRESENT ACROSS THE EASTERN PACIFIC. THE ITCZ EXTENDS FROM 04.5N90W TO 07N113W TO BEYOND 03N140W. SCATTERED MODERATE TO STRONG CONVECTION IS NOTED FROM 05N TO 10N BETWEEN 79W AND 86W. SCATTERED MODERATE TO STRONG CONVECTION IS NOTED WITHIN 300 NM N AND 240 NM S OF ITCZ BETWEEN 100W AND 125W...AND WITHIN 270 NM N OF AXIS W OF 125W. ...DISCUSSION... A SHARP MIDDLE LEVEL TO UPPER LEVEL TROUGH HAS SHIFTED SOUTHEASTWARD INTO THE AREA DURING THE PAST 24 HOURS...AND INTO THE BROAD MEAN UPPER TROUGH PREVAILING ACROSS MUCH OF THE AREA N OF 20N...AND EXTENDS FROM 36N126W TO 30N124W TO 21N128W. A SHORTWAVE HAS MOVED THROUGH THE W SIDE OF THIS TROUGH AND IS NOW SWEEPING EWD AND ACROSS NE PORTIONS OF THE AREA...AND HAS ACTED TO NUDGE THE DEEP LAYERED CUT OFF LOW ACROSS SOUTHERN CALIFORNIA N-NE. SHARP UPPER RIDGES ON BOTH SIDES OF THIS TROUGH ARE PREVENTING MUCH FORWARD PROGRESS OF THE PATTERN. A STRONG UPPER JETSTREAM CONTINUES TO MOVE THROUGH THE BASE OF THE BROAD AND MEAN UPPER TROUGH ACROSS THE AREA...EXTENDING FROM SE OF THE BIG ISLAND OF HAWAII NEAR 18N152W TO 20N129W THEN NE ACROSS CENTRAL BAJA CALIFORNIA AND ACROSS N MEXICO. SPEED DIVERGENCE ASSOCIATED WITH THE JET IS ACTING TO VENTILATE THE ACTIVE DEEP CONVECTION ALONG THE ITCZ W OF 120W. SOUTH AND SOUTHEAST OF THIS UPPER PATTERN...ELONGATED RIDGING PREVAILS AND EXTENDS E-NE INTO THE W CARIBBEAN. AT THE SURFACE...THE SHARP UPPER TROUGH SUPPORTS A DISSIPATING COLD FRONT THAT EXTENDS INTO THE AREA FROM NEAR 30N120W TO 23N126W. THIS BOUNDARY GENERALLY MARKS THE LEADING EDGE OF A NEW PULSE OF LONG PERIOD NW SWELL. MODERATE PERIOD N SWELL GENERATED OFFSHORE OF CALIFORNIA IS SPREADING S INTO THE AREA AND MIXING WITH THIS NW SWELL TO PRODUCE SEAS OF 8 TO 9 FT...AND IS EXPECTED TO INCREASE TO 8 TO 11 FT ACROSS THIS AREA DURING THE NEXT 24-36 HRS. A STRONG 1035 MB HIGH PRES CENTER IS LOCATED NEAR 38N141W AND EXTENDS A RIDGE SOUTHEAST TO THE COLD FRONT. THE PRESSURE GRADIENT BETWEEN THIS HIGH AND LOWER PRESSURE ALONG THE ITCZ IS PRODUCING A BROAD ZONE OF MODERATE TO FRESH NE TO E TRADEWINDS...COVERING THE ENTIRE AREA W OF 125W...AND S OF 20N BETWEEN 110W AND 125W. NE TRADEWINDS 20-25 KT PREVAIL ACROSS THE SW CORNER OF THE AREA W OF LINE FROM 08N140W TO 08N132W TO 18N140W...WHERE SEAS ARE PRESENTLY 9 TO 11 FT WITH MIXED NW SWELL. THE HIGH WILL SINK SLOWLY S AND WEAKEN TO AROUND 1030 MB OVER THE NEXT 2 DAYS WHICH WILL ACT TO EXPAND THE AREA OF STRONGER TRADES SLIGHTLY TO THE NE AND E...WHERE SEAS WILL REMAIN 8 TO 11 FT. E OF 110W...LIGHT TO MODERATE WINDS GENERALLY PREVAIL...WITH SEAS OF 4 TO 7 FT PREVAILING IN MIXED SWELL. THE EXCEPTION TO THIS IS ACROSS THE GULFS OF PANAMA AND PAPAGAYO...WHERE NOCTURNAL DRAINAGE FLOW WAS PRODUCING FRESH N AND NE WINDS RESPECTIVELY. GAP WINDS ACROSS THE GULF OF PAPAGAYO ARE EXPECTED TO PULSE TO 20-25 KNOTS EACH NIGHT THROUGH MORNING TONIGHT THROUGH FRIDAY. THE GULF OF CALIFORNIA...A SURFACE TROUGH EXTENDS FROM SOUTHERN CALIFORNIA S-SE INTO THE N HALF OF THE GULF. OVERNIGHT SCATTEROMETER DATA SHOWED FRESH TO STRONG S-SW WINDS FROM 29N NORTHWARD. THIS TROUGH WILL WEAKEN TODAY...AND THEN RE- STRENGTHEN OFF AND ON DURING THE NEXT 48 HOURS. THE FRESH-TO- STRONG SOUTHERLY WIND FLOW WILL PULSE EACH DAY IN RESPONSE TO THE SURFACE TROUGH. SEAS WILL BUILD BRIEFLY 5 TO 7 FEET JUST TO THE EAST OF THE TROUGH DURING THE TIMES OF STRONGEST WINDS. $$ STRIPLING