HYDROLOGIC OUTLOOK NATIONAL WEATHER SERVICE TIYAN GU 4 PM LST MON APR 30 2007
...SIGNIFICANTLY DRIER CONDITIONS NO LONGER EXPECTED... ...THIS IS THE FINAL HYDROLOGIC OUTLOOK FOR THIS DRY EVENT...
SYNOPSIS...
THE WEAK TO MODERATE EL NINO-SOUTHERN OSCILLATION (ENSO)CYCLE THAT DOMINATED THE LATTER HALF OF 2006 HAS NOW BECOME ENSO-NEUTRAL. THE EL NINO-INDUCED DROUGHT THAT OCCURRED FOR THE LAST FEW MONTHS WAS CONSIDERED OVER FOR MICRONESIA ON OUR LAST HYDROLOGIC OUTLOOK. ATMOSPHERIC CONDITIONS NOW APPEAR FAVORABLE FOR A RETURN TO NEAR NORMAL RAINFALL FOR THE MARIANA ISLANDS IN THE NEXT MONTH OR SO.
GLOBAL CLIMATE MODELS AND CURRENT OCEAN OBSERVATIONS INDICATE THAT A LA NINA COULD DEVELOP IN THE NEXT 3 MONTHS. SHOULD THIS OCCUR...IT WOULD REDUCE TROPICAL CYCLONE AND MONSOON ACTIVITY...AND COULD REDUCE REGIONAL RAINFALL TO 75-85% OF NORMAL. A 15-25% RAINFALL DEFICIT DURING THE RAINY SEASON IS MANAGEABLE FOR THE REGION.
SATELLITE IMAGERY...RAINFALL DATA AND FORECAST MODELS ALL INDICATE THAT SUBSTANTIAL CHANGES HAVE OCCURRED IN THE WESTERN PACIFIC ATMOSPHERE OVER THE LAST 2 WEEKS. THESE CHANGES IN THE ATMOSPHERE INDICATE THAT THE TRANSITION FROM THE DRY SEASON TO THE RAINY SEASON IS WELL-UNDERWAY.
SUMMARY OF IMPACTS...
FOR SAIPAN... MORE STRENGENT WATER CONSERVATION PRACTICES HAVE BEEN IMPLEMENTED BY THE COMMONWEALTH UTILITIES COMMISSION.
FOR GUAM... GRASS FIRES HAVE BEEN ABUNDANT DUE TO THE EXTREMELY DRY CONDITIONS...BUT A FEW PERIODS OF WETTING RAINS OVER THE LAST 15 DAYS HAVE GREATLY REDUCED THE NUMBER OF FIRES.
AGRICULTURE GENERALLY PROSPERS ON GUAM DURING THESE EXTENDED DRY PERIODS...SINCE FARMERS ON THE ISLAND CAN IRRIGATE CROPS. PESTS...FUNGUS/MOLD AND ROT INFESTATIONS ARE REDUCED BY THE DRY WEATHER. IN ADDITION...TROPICAL CYCLONES HAVE NOT DAMAGED THE PLANTS AND PLANT BLOSSOMS.
CLIMATE SUMMARY...
SINCE TYPHOON KONG-REY AFFECTED THE MARIANA ISLANDS FROM 1 TO 3 APRIL...SEVERAL EPISODES OF TRADE WIND-INDUCED SHOWERS HAVE OCCURRED. STRENGTHENING TRADE WINDS HAVE CONFINED TROPICAL DISTURBANCES TO LATITUDES BELOW 10 DEGREES NORTH. HOWEVER...THE ATMOSPHERE HAS BECOME MORE MOIST AND UNSTABLE...FAVORING GREATER AND MORE FREQUENT RAINFALL. OVER THE PERIOD...AVERAGE CLOUD TOPS HAVE INCREASED FROM ABOUT 10,000 FEET TO ABOUT 20,000 FEET. SOME THUNDERSTORM ACTIVITY OVER THE ADJACENT WATERS HAVE REACHED 50,000 FEET.
PRECIPITATION/TEMPERATURE OUTLOOK...
WE HAVE SHORTENED THE EXPECTED DURATION OF THE EXTENDED DRY PERIOD FOR THE MARIANAS. FOR GUAM AND ROTA...DRIER THAN NORMAL CONDITIONS COULD LAST THROUGH MID-MAY. FOR TINIAN...SAIPAN AND THE NORTHERN ISLANDS...THESE CONDITIONS COULD LAST THROUGH MID-JUNE.
RAINFALL AMOUNTS HAVE RANGED FROM 0.01 INCH TO 0.35 INCH PER TRADE WIND-INDUCED RAIN EPISODE. THIS TYPE OF SHOWERS WILL TEND TO REDUCE THE DAY-TO-DAY FIRE DANGER AND WILL KEEP THE GRASS AND PLANTS GREEN...BUT WON'T DO MUCH TO REDUCE GROUND WATER OR SURFACE WATER DEFICITS. THE SHOWERS WILL...HOWEVER...HELP RESTORE WATER LEVELS IN CATCHMENT TANKS.
PARTLY CLOUDY SKIES WILL DOMINATE THE REGION AND THE SUN WILL BE NEARLY OVERHEAD FOR THE NEXT MONTH OR SO. THUS...HIGH TEMPERATURES FOR GUAM WILL BE IN THE HIGH 80S...87 TO 89. THOSE FOR THE SMALLER ISLANDS OF SAIPAN...ROTA AND TINIAN WILL BE 1 TO 2 DEGREES COOLER.
DRIER THAN NORMAL CONDITIONS ALONG WITH BREEZY TRADE WINDS WILL KEEP THE POTENTIAL FOR WILDFIRES HIGHER THAN NORMAL FOR THE NEXT FEW WEEKS. SOME OF THIS POTENTIAL WILL BE NEGATED BY THE SPOTTY RAINS. AS ALWAYS RESIDENTS OF THE MARIANAS SHOULD TAKE EXTREME CAUTION WHEN BURNING TRASH. CHECK WITH LOCAL FIRE AND ENVIRONMENTAL OFFICIALS FOR BURNING RESTRICTIONS. AND...SMOKERS SHOULD ALWAYS USE ASHTRAYS TO DISCARD CIGARETTE BUTTS.
HYDROLOGIC SUMMARY AND OUTLOOK...
TYPHOON KONG-REY ADDED SOME GROUND WATER TO THE WATER LENS ON SAIPAN AND TINIAN. HOWEVER...UNLESS ANOTHER TROPICAL SYSTEM AFFECTS THE ISLANDS IN THE NEXT 1 TO 2 MONTHS...LITTLE ADDITIONAL RELIEF CAN BE EXPECTED. DESPITE THE DRY CONDITIONS...GUAM'S VAST GROUND WATER RESOURCES ARE IN GOOD SHAPE. SURFACE WATER RESOURCES ON GUAM WILL CONTINUE TO SLOWLY DIMINISH FOR THE NEXT MONTH OR TWO. WE STILL ENCOURAGE CONTINUED VOLUNTARY WATER CONSERVATION MEASURES IN THE MARIANA ISLANDS...ESPECIALLY ON SAIPAN...FOR THE NEXT MONTH OR TWO.
RELATED WEB SITES (SMALL CASE LETTERS)...
HTTP://WWW.WEATHER.GOV/GUAM/ (UNDER MENU ITEM ENSO) HTTP://WWW.SOEST.HAWAII.EDU/MET/ENSO/INDEX2.HTML HTTP://WWW.GUAMHS.ORG/MAIN/ HTTP://WWW.CNMIEMO.GOV.MP/
NEXT ISSUANCE DATE...
GIVEN THAT THE TRANSITION FROM THE DRY SEASON TO THE RAINY SEASON IS WELL-UNDERWAY...THIS IS THE FINAL HYDROLOGIC OUTLOOK FOR THIS EXTENDED DRY EPISODE. STAY TUNED TO NOAA WEATHER RADIO OR LOCAL MEDIA OUTLETS FOR THE LATEST WEATHER INFORMATION. DIAL 211 ON GUAM FOR THE SAME INFORMATION.
ACKNOWLEDGMENTS...
WE WOULD LIKE TO ACKNOWLEDGE OUR PARTNERS AT THE CLIMATE PREDICTION CENTER...THE PACIFIC ENSO APPLICATIONS CENTER...THE UNIVERSITY OF GUAM...THE UNIVERSITY OF HAWAII...THE HONOLULU FORECAST OFFICE...THE GUAM HOMELAND SECURITY/OFFICE OF CIVIL DEFENSE AND THE COMMONWEALTH OF THE NORTHERN MARIANA ISLANDS EMERGENCY MANAGEMENT OFFICE.
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GUARD