AFDPDT AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PENDLETON OR 254 AM PST TUE JAN 18 2022 .SHORT TERM...TODAY THROUGH THURSDAY...WEAK SHORTWAVE IN NW FLOW ALOFT WILL MOVE ACROSS THE REGION TODAY. NOT MUCH IN THE WAY OF SENSIBLE WEATHER CONCERNS WITH THIS FEATURE EXCEPT FOR A FEW MOUNTAIN RAIN AND SNOW SHOWERS. THE FOG AND FREEZING FOG REMAINS THE PRIMARY CONCERN FOR TODAY. A FREEZING FOG ADVISORY CONTINUES FOR A LARGE PORTION OF THE FORECAST AREA. THE SHORTWAVE MAY PROVIDE SOME MIXING AND HELP REDUCE THE FOG AND STRATUS TO SOME EXTENT. CURRENTLY KPDT AND KALW ARE REPORTING 10SM CLR WITHIN THE ADVISORY WHILE KHRI IS REPORTING 1/4SM FG OUTSIDE OF THE ADVISORY AREA. IT LOOKS LIKE THE DENSE FOG IS PATCHY SO FAR EARLY THIS MORNING. WILL HOLD ONTO THE CURRENT HIGHLIGHTS BUT MAY NEED TO ADJUST THEM IN THE COMING HOURS BASED ON TRENDS IN THE AREA OBSERVATIONS. OTHERWISE AN UPPER RIDGE WILL BUILD OFFSHORE IN THE WAKE OF THE SHORTWAVE TROUGH AND PROVIDE DRY WEATHER THROUGH WEDNESDAY WITH PATCHY FOG AND STRATUS. ON WEDNESDAY NIGHT AND THURSDAY A SOMEWHAT STRONGER SHORTWAVE TROUGH WILL TOP THE RIDGE AND PROVIDE A GOOD CHANCE OF MOUNTAIN RAIN AND SNOW. SNOW LEVELS WILL CLIMB TO 6000-7000 FEET THURSDAY. THE CONDITIONAL PROBABILITY OF FREEZING RAIN FROM THE NBM FOR THE YAKIMA AND KITTITAS VALLEYS IS HIGH ENOUGH TO INCLUDE AT LEAST A SLIGHT CHANCE OF FREEZING RAIN WEDNESDAY NIGHT AND THURSDAY MORNING. SOUTH TO SOUTHWEST WINDS WILL BE INCREASING DURING THE LATE MORNING INTO THE AFTERNOON THURSDAY WHICH SHOULD HELP BRING IN SOME WARM AIR AND PROMOTE MIXING SUCH THAT TEMPERATURES WILL RISE ABOVE FREEZING AND CHANGE ANY MIXED PRECIPITATION IN THE VALLEYS TO RAIN. 78 .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY... RELATIVELY BENIGN WEATHER EXPECTED THROUGH THE FORECAST PERIOD. THE SHORTWAVE TROUGH WILL BE EXITING THE REGION BY THURSDAY NIGHT EARLY FRIDAY MORNING. PRECIP ASSOCIATED WITH THE SHORTWAVE WILL LINGER IN THE MOUNTAINS AND WILL BE PRIMARILY RAIN, EXCEPT IN THE HIGHER ELEVATIONS THEN TAPER OFF BY EARLY FRIDAY.SNOW LEVELS ARE EXPECTED TO REMAIN ABOVE 2000 FEET DURING THE FORECAST PERIOD. THE WINDS ASSOCIATED WITH THE SURFACE FRONT WILL ALSO BEGIN TO DECREASE AS THE SHORTWAVE MOVES FARTHER TO THE EAST. BY FRIDAY MORNING WINDS SHOULD BE RELATIVELY LIGHT FRIDAY WE BEGIN TO SEE A ROBUST RIDGE OF HIGH PRESSURE MOVE OVER THE FORECAST REGION. THE MODELS ARE IN AGREEMENT THAT THE RIDGE WILL PERSIST WELL INTO NEXT WEEK BRINGING WITH IT VERY DRY CONDITIONS FOR THE ENTIRE FORECAST AREA. HIGH TEMPERATURES WILL REMAIN RELATIVELY COOL IN THE MID TO UPPER 40S AND WE COULD SEE LOWS IN THE UPPER 20S TO LOW 30S IN MOST ARES WITH THE EXCEPTION THE BASIN AND ADJACENT VALLEYS, WHICH COULD SEE TEMPERATURES IN THE LOW 20S. THE PRIMARY CONCERN DURING THE FORECAST PERIOD WILL BE THE POTENTIAL FOR FOG AS THE RIDGE MOVES OVER AND STALLS AN INVERSION WILL LIKELY SET UP BRINGING IN DENSE FOG FOR THE COLUMBIA BASIN AND ADJACENT VALLEYS THAT COULD LINGER WELL INTO THE AFTERNOON. BENNESE/90 && .AVIATION...06Z TAFS...VARIABLE CONDITIONS ARE CURRENTLY BEING OBSERVED AT TAF SITES; VFR AT KDLS/KRDM/KBDN WITH ONLY FEW- SCT CIRRUS, LIFR AT YKM/PSC WITH A LOWERING STRATUS DECK OF OVC004, AND VLIFR AT KPDT/KALW DUE TO A SHALLOW LAYER OF 1/4SM TO 1/2SM FOG WITH VV001 TO VV002. EXPECTING CONDITIONS TO REMAIN FAIRLY STABLE INTO MORNING AT KPDT/KALW WHILE FOG MAY DEVELOP AT KYKM/KPSC. OTHERWISE, CEILINGS WILL LOWER AT KDLS/KRDM/KBDN OVERNIGHT THROUGH MORNING TO AROUND 2-5KFT AS A WEAK SYSTEM APPROACHES. WINDS WILL GENERALLY BE LIGHT THROUGH THE PERIOD. PLUNKETT/86 && .PRELIMINARY POINT TEMPS/POPS... PDT 48 32 45 33 / 10 10 0 10 ALW 47 34 46 35 / 10 20 0 10 PSC 43 32 43 34 / 0 10 0 10 YKM 42 28 41 30 / 0 10 0 20 HRI 47 32 43 34 / 0 10 0 10 ELN 41 29 39 28 / 0 10 0 20 RDM 48 31 48 33 / 0 10 0 0 LGD 39 30 41 31 / 10 30 0 10 GCD 44 31 44 33 / 0 20 0 0 DLS 46 36 45 36 / 10 10 10 30 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...FREEZING FOG ADVISORY UNTIL NOON PST TODAY FOR ORZ050-507-508- 510. WA...FREEZING FOG ADVISORY UNTIL NOON PST TODAY FOR WAZ026-027-029- 521. &&