FXUS66 KPDT 040544 CCA
AFDPDT
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE PENDLETON OR
844 PM PST THU DEC 3 2009
CORRECTED FOR FORMAT
UPDATED FOR AVIATION DISCUSSION
.UPDATE...TONIGHT...FAIRLY QUIET TONIGHT AS CURRENT FORECAST REMAINS
ON TRACK...WITH MINOR MODIFICATIONS. SMALL CHANGES HAVE BEEN MADE TO
BUMP UP WINDS IN THE GRANDE RONDE VALLEY...AS PRESSURE GRADIENTS ARE
DRAWING WINDS OUT OF THE SOUTH AT ABOUT 10 TO 20 MPH. THESE WINDS
WILL LIKELY CONTINUE OVERNIGHT AND INTO THE MORNING HOURS. CURRENT
OBS ALONG WITH IR SATELLITE IMAGERY INDICATE A FAIR AMOUNT OF CIRRUS
AND LOW LEVEL STRATUS ACROSS THE AREA. SO HAVE INCREASED SKY
COVERAGE FOR THE TONIGHT PERIOD. HAVE NOT YET SEEN A NEED TO ADJUST
MIN TS FOR TONIGHT...BUT WILL CONTINUE TO MONITOR AND MAKE UPDATES
IF WARRANTED. WEBER
&&
AVIATION...06Z TAFS...LOW CLOUDS CONTINUE TO LINGER ACROSS
KPDT...KDLS...KALW...AND KPSC. EXPECT THAT THESE LOW CIGS WILL
CONTINUE OVERNIGHT AND DIMINISH IN THE LATE MORNING HOURS. THIS IS
DUE TO AN APPROACHING WEATHER SYSTEM WHICH WILL INCREASE WESTERLY
WINDS TOMORROW MORNING. THE WINDS SHOULD MIX OUT MOST OF THE LOW
CLOUDS BY TOMORROW AFTERNOON. HOWEVER PATCHY FOG WILL STILL BE OF
CONCERN TONIGHT FOR THESE SITES. WINDS SHOULD REMAIN LESS THAN 10
KTS. WEBER
&&
.PREV DISCUSSION... /ISSUED 230 PM PST THU DEC 3 2009/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT. HIGH PRESSURE WILL
REMAIN ENTRENCHED ACROSS THE AREA. LOW CLOUDS AND FOG WILL PERSIST
OVER THE LOWER COLUMBIA BASIN TONIGHT. A STORM SYSTEM WILL TAKE AIM
ON THE PACNW FRIDAY AS COLD AIR DROPS SOUTH FROM CANADA AND INTO THE
TWO STATE AREA. SOME SNOW SHOWERS WILL DEVELOP OVER THE LOWER
COLUMBIA BASIN WITH GREATER CHANCES OVER THE BLUE/WALLOWA MTNS WHERE
SOME ACCUMULATING SNOW IS POSSIBLE INTO SATURDAY THROUGH SATURDAY
NIGHT. BELOW NORMAL TEMPS ARE LIKELY TO CONTINUE INTO THE BEGINNING
OF THE WEEKEND.
LONG TERM...SUNDAY THROUGH THURSDAY...SCREAMING MESSAGE FOR THE
EXTENDED IS TURNING COLDER AND THE POTENTIAL FOR THE FIRST MAJOR
WINTER STORM NEXT WEDNESDAY AND THURSDAY. REGION WILL BE UNDER A
COLD NORTHERLY FLOW ON SUNDAY USHERING COLD MOIST CANADIAN AIR INTO
THE REGION. THERE WILL BE SOME SNOW SUNDAY AND INTO MONDAY MAINLY
ACROSS NORTH CENTRAL OREGON AS THE COLD AIR MOVES UP OUT OF THE
COLUMBIA BASIN INTO THE HIGHER CENTRAL OREGON PLATEAU. THIS UPSLOPE
FLOW WILL FAVOR THE FOOTHILLS OF THE BLUE MOUNTAINS AND THE SOUTHERN
BLUE MOUNTAINS BUT COULD STILL SEE SNOW SHOWERS JUST ABOUT
EVERYWHERE EVEN THE COLUMBIA BASIN. TEMPERATURES WILL BE TURNING
COLDER AND SNOW COVER WILL BE A BIG FACTOR IN JUST HOW COLD THE
MORNING LOWS WILL BE BUT WOULD NOT BE SURPRISED TO SEE SINGLE DIGIT
LOWS. HIGH TEMPERATURES BY EARLY NEXT WEEK WILL ONLY BE IN THE TEENS
AND LOW 20S IN THE BASIN. THERE WILL BE BRIEF PERIOD OF HIGH
PRESSURE LATE MONDAY AND TUESDAY WHICH WILL HELP TRAP THE COLD AIR
IN PLACE. THEN A WESTERLY FLOW WILL BEGIN TO PUNCH INTO THE REGION
WEDNESDAY AND THURSDAY. THIS HAS THE POTENTIAL OF TURNING INTO A
MAJOR WINTER STORM OF THE SEASON WITH SNOW AND FREEZING RAIN ACROSS
THE FORECAST AREA WEDNESDAY AND THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 18 37 19 34 / 0 0 20 20
ALW 22 40 22 37 / 0 10 20 20
PSC 17 38 20 39 / 0 10 10 10
YKM 14 40 18 38 / 0 10 10 10
HRI 14 40 17 36 / 0 0 10 10
ELN 17 40 20 38 / 0 10 10 10
RDM 18 42 12 37 / 0 0 10 10
LGD 20 36 22 32 / 0 10 30 30
GCD 22 39 20 34 / 0 0 20 20
DLS 20 39 24 41 / 0 0 20 10
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
FRIDAY : GREEN
SATURDAY : GREEN
SUNDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
89/89/89
