textproduct: Pendleton

DISCUSSION

The ridge had broke down into a more zonal pattern today along with this ongoing precip activity. A shortwave will then move across our forecast area Monday morning hours as precip linger over the mountain areas. StormTotalQPF amounts will exceed to 0.45 inch or higher for the lower elevation and 1 inch or higher for the mountain areas (the crest of OR Cascades and Northwest Blues). The NBM Probability of 24 hr Precipitation suggested a 35-55% prob of 0.45 inch or more and 70-90% prob for 1 inch or more for the crest of OR Cascades and Northwest Blue Mountains, thanks to the stalling cold front. The WA Cascades may see precip of 0.25-0.35 inch, though the probability will be low (20-40%).

Light mountain snow will accumulate up to 1 inch or more over the WA Cascades, the crest of OR Cascades, Northwest Blues and southern parts of Wallowa County through Monday morning (>50% prob). However, the Northwest Blues may see snow accumulations up to 6 inches at 5 kft or below, which could potentially become advisory level. But with slightly high snow ratios, it seems to look favorable for wet snow. However, we will monitor that area and make adjustments if need. Portions of the eastern mountains (Grande Ronde Valley, Southern Blue Mountains-OR, and John Day Highlands) and Northwest Blues may receive snowfall of 0.5-1 inch (40-80% prob). Breezy winds (Gusts of 15-25 mph) will develop this afternoon into early Monday morning across majority of our forecast area (50-70% prob). The crest of OR Cascades will be gusty overnight at 25-35 mph with the stalling frontal system. NBM suggest a 30-50% prob for gusts exceeding 25 mph.

Tuesday through Thursday, a troughing pattern extends outward to the CA coast. Most of our forecast area will be dry dry conditions. However, we may a weak plume of moisture developing for the Deschutes County and eastern OR mountains through early Thursday morning. This could bring light rain up to 0.05 inch, but confidence remains low (<30%). A band of precip will return across the region Friday through the weekend where mountain snow and lower elevation rain evolves. QPF amounts will reach to 0.05 inch with 0.10 inch or less for the mountain areas, but confidence is low (<20%) at this time. Feaster/97

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Rain chances will dwindle from west to east late Tonight and early Monday morning. In the meantime, locations like PDT and ALW will still be prone to some lower ceilings, in the IFR and lower range. Expect VLIFR ceilings at ALW for at least a few more hours overnight until the rain ends, which could be around 9z base on HREF (ensemble trends). Terminals farther west like RDM BDN and YKM have seen marked improvement to the ceilings, and will remain VFR for the balance of the TAF period.

Preliminary Point Temps/PoPs

PDT 35 49 30 46 / 100 30 0 0 ALW 37 49 32 47 / 100 40 0 0 PSC 36 54 30 49 / 90 10 0 0 YKM 31 50 28 46 / 70 10 0 0 HRI 36 53 29 46 / 90 20 0 0 ELN 31 45 27 42 / 50 20 0 0 RDM 27 45 23 46 / 60 0 0 0 LGD 33 45 26 46 / 100 50 0 0 GCD 33 43 26 46 / 90 10 0 10 DLS 38 51 34 48 / 80 20 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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