textproduct: Pendleton

AVIATION...18Z TAFs

VFR conditions to prevail through the period. CIGs are expected to remain above 10kft through the period, however site DLS will continue to see 1kft few CIGs through 19Z this morning. Winds will be light, 12kts or less, through the period. Lawhorn/82

DISCUSSION

Increasing cirrus has been observed on GOES satellite overnight as a southwesterly to westerly flow a as weak warm advection signal was observed over the region. Light winds will continue today as 1026hPa surface high pressure remains under a mean 1000-500 mb ridge. Mid level water vapor shows a distinct vorticity maximum near 45.3 lat and -127.5 lon, spreading east toward the Pac NW. Some of the CAM models signal very light simulated radar echos with this however the HREF Probability matched means are dry until Tuesday evening when a far more robust system supported with a fetch of Pacific moisture impinging on the Cascades for a chance of snow, rain and potential freezing rain Tuesday Night into Wednesday Morning. This is all of low confidence for the lower elevation areas as mid levels of model sounding look dry initially. Snow however is of higher confidence in the Cascades as the probabilities of precipitation are from 60 to 80 percent.

With the recent cold temperatures and incoming snow and rain, freezing rain might be a risk (20% or less) for Tuesday night creating localized slippery condition in some valleys and lower elevations. The temperatures should be trending warmer through this period, mitigating the risk as rain becomes the dominant p-type (any icing risk should end after Wednesday mornings lows). From this point and on through the weekend, a gradual warming is indicated from NBMs highs incremental shift from highs Wednesday at least in the mid 40s (25th percentile) to the low 50s by the weekend. Likewise the higher end of the range of outcomes would be from 50 degrees to around 60 degrees (75th percentile) for the Columbia Basin.

The 8 to 14 outlook strongly favors dry and warmer than normal with confidence of 50 to 60% for drier than normal conditions and 70-80% for warmer than normal weather.

PRELIMINARY POINT TEMPS/POPS

PDT 37 24 37 26 / 0 0 0 10 ALW 36 25 38 29 / 0 0 0 20 PSC 35 23 38 26 / 0 0 0 10 YKM 35 24 37 26 / 0 0 0 10 HRI 35 23 36 26 / 0 0 0 10 ELN 32 23 33 25 / 0 0 0 20 RDM 48 25 46 28 / 0 0 0 10 LGD 40 25 42 31 / 0 0 0 20 GCD 45 25 46 29 / 0 0 0 20 DLS 40 28 39 30 / 0 0 0 30

PDT WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None.