textproduct: Pendleton

KEY MESSAGES

- Chances of isolated to scattered thunderstorms tomorrow through midweek. Some dynamics a bit uncertain with models struggling with the offshore low.

- Climatologically normal dryness through the region with light to slightly elevated winds through the week.

DISCUSSION

Satellite shows a trail of mid to upper level clouds over the Eastern Mountains with light returns on radar. Conditions will continue to clear out overnight with the absence of a lifting mechanism to streamline precipitation through the early morning hours. Through the next few days, guidance is having trouble (namely the ECMWF vs GFS vs GEPS ensemble members) how the low pressure system will behave through its life-cycle, giving less confidence with the forecast this week. The European model solutions like to be more aggressive with pushing the low pressure system on-shore, bringing wetter and cooler conditions. The GFS, on the other hand, brings the opposite solution of keeping the low mostly off-shore and not allow the forcing mechanism to initiate more widespread rain showers and isolated thunderstorms.

Looking at LREF clusters, 64% of the members (which are notably skewed towards the European model) bring the low pressure system closer to shore by Tuesday through Wednesday afternoon, initiating slight chances (10-30%) of thunderstorms across Central Oregon and the Southern Blues. Fire weather concerns can manifest with the potential of some dry thunderstorms developing. Current PWAT values in the thunderstorm development region hover between 0.8-1.4 inches, developing mostly wetter thunderstorms (40-70% confidence) with isolated areas of dry storms possible. Model guidance completely diverges by late Thursday afternoon with only 41% of clusters already bringing the low on-shore, bringing a cooler and wetter pattern while the remaining keep the system off- shore.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

VFR conditions across all sites, which will stay the course through the period. Breezy winds of 10-15kts at KDLS late afternoon and extending through the evening, with winds of 10kts or less elsewhere. 25kft ceilings through Tuesday evening, dropping to 10kft for KRDM/KBDN late in the period. 75

Preliminary Point Temps/PoPs

PDT 62 93 62 95 / 0 10 0 0 ALW 66 95 66 98 / 0 10 10 0 PSC 62 96 63 99 / 0 0 0 0 YKM 62 98 65 98 / 0 0 0 10 HRI 64 96 66 98 / 0 0 0 10 ELN 59 94 62 95 / 0 0 0 10 RDM 56 93 57 91 / 0 0 40 40 LGD 63 90 60 94 / 0 30 10 10 GCD 61 91 59 93 / 0 30 20 10 DLS 63 97 67 98 / 0 0 0 10

PDT WATCHES/WARNINGS/ADVISORIES

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