AGUS76 KPTR 311851
HMDPTR
HYDROMETEOROLOGICAL DISCUSSION
NORTHWEST RIVER FORECAST CENTER PORTLAND OR
11:35 AM PDT FRI MAY 31 2013
THIS IS THE LAST HYDROMETEOROLOGICAL DISCUSSION (HMD) FOR THIS WATER YEAR'S
ACTIVE RUNOFF SEASON. HMD ISSUANCE WILL RESUME NEAR THE END OF SEPTEMBER UNLESS
HYDROMETEOROLOGICAL CONDITIONS WARRANT AN EARLIER RESUMPTION.
...HYDROMETEOROLOGICAL CONDITIONS...PAST 24 HOURS...4 AM - 4 AM...
LIGHT MIXED SHOWERS TRAILING BEHIND AN ACTIVE GREAT PLAINS TROUGH GENERATED 
SOME SCATTERED 0.25 TO 0.5 INCH MIXED VALLEY RAIN AND UPPER HEADWATER WATER 
EQUIVALENT SNOW MAINLY ACROSS WESTERN WASHINGTON...NORTHERN IDAHO...THE TETONS
...AS WELL AS THE FAR UPPER COLUMBIA NORTH OF THE CANADIAN BORDER. ELSEWHERE
MOSTLY DRY CONDITIONS  PREVAILED. COOL AIR IN THE WAKE OF THE TROUGH TO OUR EAST
DROPPED OUR THURSDAY TEMPERATURES TYPICALLY DOWN AROUND 4 TO 10 DEGREES BELOW 
NORMAL. FREEZING LEVELS RANGED BETWEEN 5000 FEET AT QUILLAYUTE...7700 FEET AT
BOISE...AND 11300 FEET AT MEDFORD. 
  
...OBSERVED HYDROLOGIC CONDITIONS...
THERE WAS A MIX OF MINOR NORTHERN TIER RISES THAT FLATTENED OUT INTO GRADUAL
RECESSIONS ACROSS OUR SOUTHERN TIER. 
...HYDROMETEOROLOGICAL FORECAST...MAY 31 - JUN 04...
EXPECT AN EARLY AND MID PERIOD PICK-UP IN SOME SCATTERED SHOWERS ALONG OUR
NORTHEASTERN TIER AND FRONT-RANGE BASINS AS SOME WESTWARD BACK-PHASED GULF OF 
MEXICO MOISTURE CLIPS US WHILE WRAPPING AROUND OCCLUSIONS IN THE GREAT PLAINS.
OTHERWISE...LOOK FOR GRADUALLY BUILDING RIDGING INTO THE REGION TO RESULT IN
MOSTLY DRY WEATHER ELSEWHERE...ALONG WITH TEMPERATURES GRADUALLY WARMING UP
TO AROUND 7 TO 14 DEGREES BELOW NORMAL BY THE END OF THE PERIOD.
...HYDROLOGIC CONDITIONS...
EARLY TO MID PERIOD DOMINATE RECESSIONS TEND TO TURN AROUND INTO LATER
PERIOD BUILDING SNOWMELT RISES TOWARD AND NORTH OF THE CANADIAN BORDER AS 
SNOWMELT RAMPS UP ACROSS WARMING BASINS STILL HOLDING ONTO SEASONABLE HEAD-
WATER SNOWPACKS. SOME PRECIPITATION AMPLIFIES THESE REGIONAL SNOWMELT RISES 
A BIT TOWARD OUR NORTHEASTERN TIER AROUND MID PERIOD.
...6-10 DAY OUTLOOK...JUN 05 - JUN 09...
CONFIDENCE IS NOT VERY HIGH IN SOME LONG RANGE GUIDANCE THAT'S HINTING AT A
CHANCE OF OCCASIONAL ONSHORE SHOWERS SHIFTING IN ACROSS THE REGION AT TIMES.
HAVE LEANED FORECAST MORE TOWARD LATEST EUROPEAN MODEL OUTLOOK THAT TENDS TO
PROLONG A HIGHER HEIGHT AND DRYER PATTERN ACROSS THE REGION ESSENTIALLY 
THROUGH THE ENTIRE PERIOD. WITH 7 TO 15 DEGREE ABOVE NORMAL TEMPERATURES
EARLY IN THE PERIOD...LOOK FOR CRESTING SNOWMELT RISES PEAKING OUT ABOVE
PROBLEM LEVELS ON THE NACHES NEAR YAKIMA WASHINGTON...AND GETTING NEAR TO
PROBLEM LEVELS ALONG THE FLATHEAD NEAR GLACIER PARK MONTANA...AS WELL AS ON
THE KOOTENAI IN THE NORTHERN PANHANDLE OF IDAHO.
ML/CO/JS/BG/SK
VISIT US ON THE WEB AT HTTP://WWW.NWRFC.NOAA.GOV FOR DETAILED
GRAPHICAL PRECIPITATION...FREEZING LEVEL...AND TEMPERATURE FORECASTS.
$$