000 AXPZ20 KNHC 170328 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI APR 17 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0130 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 05N77W TO 07N90W TO 05N100W TO 07N117W TO 05N140W. SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 45 NM EITHER SIDE OF THE ITCZ AXIS FROM 90W TO 95W. SCATTERED MODERATE CONVECTION ALSO LIES WITHIN 120 NM N AND 60 NM S OF THE ITCZ AXIS BETWEEN 133W AND 37W. ...DISCUSSION... N OF 20N... THE TIGHT PRESSURE GRADIENT BETWEEN A 1032 MB HIGH CENTERED NEAR 32N130W AND BROAD LOW PRES OVER THE EASTERN ROCKIES IS PRODUCING A SWATH OF NW WINDS TO 25 KT WITHIN 270 NM W OF THE BAJA PENINSULA COAST N OF 25N. THESE WINDS ARE EXPECTED TO GRADUALLY DIMINISH AS HIGH PRES N OF AREA WEAKENS AND RETREATS FARTHER N. SEAS ARE ANALYZED UP TO 11 FT OFF THE BAJA PENINSULA COASTLINE WITH NW SWELL. CONDITIONS SHOULD STEADILY SUBSIDE OVER THE NEXT FEW DAYS AS WINDS RELAX IN THIS REGION. NW WINDS UP TO 25 KT WERE ALSO NOTED IN THE GULF OF CALIFORNIA N OF 27N ACCORDING TO THE 1242 UTC QUIKSCAT PASS AND CONFIRMED BY THE 1638 UTC ASCAT PASS. A SURFACE OBSERVATION NEAR LORETO...BAJA CALIFORNIA SUR...SHOWED WINDS TO 20 KT AT 0000 UTC HAVE SPREAD SOUTH TO 26N. WINDS WILL CONTINUE TO SHIFT SOUTH OVER THE NEXT FEW HOURS AND MODEL GUIDANCE SUGGESTS THEY WILL PERSIST OVER THE GULF FOR THE NEXT FEW DAYS. S OF 20N... WHILE THE LA CUMBRE VOLCANO ON ISLA FERNANDINA IN THE GALAPAGOS ISLANDS LOCATED AT 00.4S91.5W CONTINUES TO ERUPT...THE GOVERNMENT OF ECUADOR REPORTS THAT THE RESULTING PLUME CONTAINS VAPOR AND GASES WITH NO SIGNIFICANT ASH. THE WASHINGTON VAAC HAS DISCONTINUED ASHFALL ADVISORIES. HOWEVER...MARINERS SHOULD STILL EXERCISE CAUTION AS GASES...INCLUDING SULFUR DIOXIDE...EXTEND AS MUCH AS 1200 NM TO THE W OF THE VOLCANO. NASA/OMI IMAGERY FROM 2254 UTC SHOWS ELEVATED LEVELS OF SULFUR DIOXIDE IN THE AREA FROM FROM 01N TO 03S BETWEEN 91W AND 105W WITH A SECOND PLUME FROM 03N TO 02S BETWEEN 111W AND 117W. EXPOSURE TO THIS GAS CAN BE DANGEROUS...CAUSING IRRITATION TO EYES AND SKIN. GAP WINDS... NE WINDS IN THE 20 TO 25 KT CONTINUE TO FUNNEL THROUGH THE GULF OF PAPAGAYO. THIS FLOW SHOULD CONTINUE TO PULSE OVER THE NEXT FEW DAYS...ESPECIALLY IN THE EARLY MORNING HOURS WHEN DRAINAGE FLOW IS AT A MAXIMUM. TRADE WINDS... THE ASCAT PASS FROM AROUND 1820 UTC SHOWED EASTERLY TRADES TO 25 KT ACROSS A LARGE PORTION OF THE FORECAST AREA N OF THE ITCZ W OF ABOUT 117W. BY FRI NIGHT AND SAT THE SURFACE HIGH TO THE NORTH IS EXPECTED TO WEAKEN...MOVE FARTHER N...AND SHIFT THE RIDGE AXIS TO THE WEST OVER FORECAST WATERS. THIS SHOULD ALLOW THE TRADES TO DIMINISH IN SPEED AND AREA. CONVECTION... SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 120 NM N AND 60 NM S OF THE ITCZ AXIS BETWEEN 133W AND 37W. IT IS ALSO ON THE SOUTHWESTERN EDGE OF AN ELONGATED REGION OF BROAD UPPER LEVEL DIFFLUENCE WITH SOUTHEASTERLY FLOW 40 TO 50 KT N OF THE AXIS AND NORTHEASTERLY TO EASTERLY FLOW AT 20 TO 30 KT S OF THE AXIS. THE CONVECTION IS IN A REGION OF STRONG LOW LEVEL CONVERGENCE BETWEEN 25 KT TRADE WINDS TO THE NORTH AND 10 TO 15 KT EASTERLY WINDS TO THE SOUTH ACCORDING TO THE 1822 UTC QUIKSCAT PASS AND IT LIES WITHIN A POOL OF LOW TO MID LEVEL MOISTURE WITH PRECIPITABLE WATER VALUES IN THE 2.0 TO 2.25 INCH RANGE. THIS AXIS IS EXPECTED TO GRADUALLY SHIFT WESTWARD OVER THE NEXT DAY OR TWO. SCATTERED MODERATE CONVECTION CAN ALSO BE FOUND WITHIN 45 NM EITHER SIDE OF THE ITCZ AXIS FROM 90W TO 95W IN A REGION OF WEAK UPPER LEVEL DIFFLUENCE IN THE REAR RIGHT QUADRANT OF A JET MAX ON THE LEADING EDGE OF AN UPPER LEVEL TROUGH WHICH EXTENDS FROM CUBA SOUTHWESTWARD THROUGH NICARAGUA AND HONDURAS INTO THE PACIFIC. THIS TROUGH IS DISSIPATING AND THE JET MAX WILL CONTINUE EASTWARD THROUGH THE CARIBBEAN. CONVECTION HERE HAS ALREADY BEGUN TO DIMINISH. $$ SCHAUER CLARK