Wallowa Avalanche Center

Conditions Summary for October 23, 2009

Disclaimer: Wallowa Avalanche Center assumes no liability for the accuracy of the information contained in this summary. Information provided does not constitute or imply any type of forecast, advisory, or recommendation. Users are warned to use this information at their own risk.

Current Wallowa Mountains Summary:

After an early season teaser dump of up to 20" on the higher peaks October 3-5 all has been fairly quiet. Since last report,  last weekend temps on Mt. Howard and at Aneroid Lake in the mid to upper 40's and mostly sunny,  with the valley enjoying indian summer  at a high of 70 on Saturday equals melting, plain and simple.

Snow packs have certainly reached an isothermal condition this week with Howard at 3" from a high of 10" since last report and Aneroid losing 6" and showing only 6" left up there. However I can excitedly report a 1" new snow on Howard Tuesday morning which has since disappeared either from the bottom up or top down (whichever, when isothermal).

Most nights up high have been overcast from observations and this keeps the heat in with yesterday morning (Thurs.) mountain peaks in low clouds and fog. Nigh-time lows have barely crept below freezing keeping the average air temps supporting an isothermal snow pack. Winds have been alternating each day from N -> S then S -> N but generally in the 5 to 15 mph range.

Downtown Joseph on Tuesday, October 20.

Some hardy and true diehards such as our advisor Connelly Brown have taken their first turns two weekends ago returning from camp duties up the McCully Basin. But turns are a thing of the past until the snow gods begin their annual onslaught with serious determination.  Ken Bronec met  a young couple on the Lagore trail who had been up  in the Lagore Lake area.  They reported post holing in knee deep snow to get there.

The  satellite view shows another front approaching the coast.

However, snow levels remain high in Eastern Oregon:

This snow level chart is for the Enterprise area. Forecast for the weekend looks like light rain for today (Friday) with snow levels very high and SW winds, Partly sunny on Saturday with hi's about 30 and winds changing to the NW as a front with some instability passes through overnight Saturday and much cooler temps at elevation with snow showers on Sunday.

Current Regional Weather Synopsis:

FXUS66 KPDT 222246 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
346 PM PDT THU OCT 22 2009

UPDATED AVIATION DISCUSSION

.SHORT TERM...TONIGHT THROUGH SUNDAY...AN ACTIVE START TO THE
WEEKEND WITH MODELS IN EXCELLENT AGREEMENT REGARDING THE NEXT SYSTEM
TO AFFECT THE REGION BEGINNING TONIGHT. THIS SYSTEM HAS TAPPED INTO
MODIFIED TROPICAL REMNANTS OF A WESTERN PACIFIC TYPHOON AND IS
CARRYING DEEP MOISTURE. SATELLITE DERIVED PRECIPITABLE WATER VALUES
ARE RANGING BETWEEN 1.50 AND 1.75 INCHES AT THE CORE. THE LEADING
EDGE OF WARM FRONTAL PRECIPITATION WILL REACH THE WASHINGTON
CASCADES LATER THIS EVENING THEN SPREAD MAINLY OVER THE REST OF
EASTERN WASHINGTON THROUGH SUNRISE. THIS WILL BE FOLLOWED BY A FAST
MOVING COLD FRONT FRIDAY AFTERNOON AND EVENING. AFTER THE WARM FRONT
PASSES, THINK CASCADE SHADOWING WILL COME INTO PLAY BUT THERE IS
ENOUGH MOISTURE TO BRING EVERY LOCATION SOME MINIMAL RAIN AT A
MINIMUM. THE WASHINGTON CASCADE EAST SLOPES WILL AGAIN TAKE THE
BRUNT OF THE RAIN FROM BOTH THE WARM AND COLD FRONT WITH BETWEEN AN
INCH TO AN INCH AND A HALF OF RAIN EXPECTED. OTHER AREAS ACROSS THE
CWA MAY SEE 0.50 TO 1.00 INCHES EXCEPT FOR THE CASCADE SHADOWED
AREAS WHERE TYPICALLY LESS THAN 0.50 INCHES (AND LIKELY FAR LESS)
ARE EXPECTED. SNOW LEVELS WILL REMAIN FAIRLY HIGH.

BEHIND THE COLD FRONT FRIDAY NIGHT, A MORE SIGNIFICANT THREAT LIES
IN WINDS DESCENDING ALONG THE WASHINGTON CASCADE EAST SLOPES
EASTWARD TO THE WESTERN AREAS OF THE YAKIMA VALLEY AND LOWER
KITTITAS VALLEY. COULD END UP WITH PERIODS OF SUSTAINED WINDS FROM
35 TO 40 MPH AND POTENTIAL GUSTS UP TO 55 MPH. THINK MOST OF THESE
WINDS WILL RESULT FROM BREAKING GRAVITY WAVES REACHING THE SURFACE.
WILL ASK NEXT SHIFT TO ASSESS UPCOMING 00Z MODEL RUNS THEN DECIDE
WHETHER A WIND ADVISORY IS JUSTIFIED. BREEZY WINDS ARE ALSO EXPECTED
THROUGH THE GORGE AND ACROSS THE LOWER BASIN AND BLUE MOUNTAIN
FOOTHILLS BUT NOWHERE NEAR THE SAME INTENSITY AS THE AREAS MENTIONED
ABOVE.

THE COLD FRONT AND ASSOCIATED RAIN WILL LIKELY BE ENTIRELY OUT OF
THE AREA BY SUNRISE SATURDAY WITH BREEZY WINDS TO CONTINUE BUT
DIMINISHING BY SATURDAY EVENING. COOLER AND DRIER AIR WILL HAVE
FILTERED ACROSS THE AREA WITH SATURDAY NIGHT BRINGING THE COLDEST
TEMPERATURES SINCE THE LAST COLD SPELL NEARLY TWO WEEKS AGO.

ANOTHER SYSTEM APPROACHING ON SUNDAY HAS SLOWED A BIT SINCE THIS
TIME YESTERDAY BUT WILL STILL SPREAD WARM FRONTAL PRECIPITATION
ACROSS THE CWA BY SUNDAY AFTERNOON. SURFACE LOW PRESSURE CENTERED
OFF THE BRITISH COLUMBIA COAST HAS GENERATED SOME CONCERNS ABOUT
COLD AIR BEING TRAPPED ACROSS SOME OF THE WASHINGTON VALLEYS TOWARDS
THE CASCADES (INCLUDING YAKIMA AND KITTITAS) AS WINDS WILL NOT BE
SIGNIFICANT TO SCOUR OUT COLD AIR IF CLOUD COVER PROHIBITS SURFACE
HEATING. TOO SOON TO SAY WITH ANY CONFIDENCE BUT WILL NEED TO KEEP
AN EYE ON FREEZING RAIN POTENTIAL FOR THESE AREAS. /JBONK