textproduct: Pendleton

KEY MESSAGES

1. Mostly dry conditions through Wednesday night

2. Pattern shift Thursday will bring mountain showers

3. Dry conditions and warmer conditions return through the weekend

DISCUSSION

Current night time satellite shows very little cloud cover over the region. Satellite mostly shows areas of fog through the Gorge, portions of the Basin and adjacent valleys as well as central OR. These conditions will persist through the evening until sunrise when the fog will burn off.

A transient weak ridge will build into the region behind the upper level low that has moved to the southeast. This ridge will keep the region under dry conditions through Thursday. In house climate shows the region to be slightly below seasonal average temperatures through the Basin but above average temperatures along the Blues, the eastern mountains and central OR. NBM and REFS ensembles show the temperatures to be in the 50s across the vast majority of the region through Thursday.

Thursday night models show an upper level shortwave trough moving into the region bringing with it chances of mountain showers. 70-90% of the REFs raw ensembles shows the Cascades will receive up to 0.05 inches of precipitation in 24 hours while the Blues and eastern mountains will see 0.01-0.04 inches in 24 hours. Snow levels will remain above 5500 feet some the precipitation will fall as rain along the Cascades.

After the system passes on Thursday, deterministic models are in form agreement with a zonal flow pattern setting up across the region. This will dry the region back out and allow the temperatures to steadily increase through Saturday. In house climate calculations show that by Saturday temperatures will be 10-15 degrees above seasonal normal. NBM ensembles show temperatures to be in the low to mid 60s by Saturday with a few isolated locations seeing the high 60s with 60-80% of the NBM raw ensembles in agreement.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Variable conditions across sites this morning, with VFR at KPDT/KYKM/KALW, MVFR at KPSC due to visibilities of 3SM, and IFR at KRDM/KDLS in response to low ceilings of around 500 feet. These conditions are expected to improve later this morning, with all terminals gaining VFR status by the afternoon. A system will be approaching tonight, bringing periods of light rain and lower MVFR ceilings to KDLS/KPDT/KALW. 75

Preliminary Point Temps/PoPs

PDT 52 38 56 32 / 0 50 20 0 ALW 51 42 54 38 / 0 40 50 0 PSC 54 38 59 32 / 0 20 10 0 YKM 52 36 59 33 / 0 30 0 0 HRI 52 38 59 32 / 0 40 10 0 ELN 52 34 54 28 / 0 40 0 0 RDM 58 33 53 26 / 0 20 0 0 LGD 55 37 52 31 / 0 20 40 0 GCD 57 38 52 29 / 0 10 20 0 DLS 54 42 60 37 / 0 40 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Dense Fog Advisory until 10 AM PST this morning for WAZ027. Freezing Fog Advisory until 10 AM PST this morning for WAZ026. OR...Dense Fog Advisory until 10 AM PST this morning for ORZ044.