textproduct: Pendleton

KEY MESSAGES

1. Dry conditions will remain through Thursday afternoon

2. Mountain precipitation Thursday night becoming widespread Friday

3. Breezy conditions Friday

DISCUSSION

Current satellite shows mostly cirrus clouds moving over the region. Dry conditions will persist today with temperatures in the upper 60s to low 70s and light diurnally driven winds.

CAMs models show weak ridging remaining over the region through the day today. This will keep the region under dry and warm conditions. Looking at in office calculations, temperatures are 2 to 5 degrees above seasonal averages for this time of year. Temperatures Thursday are also above normal by nearly 10 to 15 degrees with temperatures in the mid to upper 70s with some isolated 80s in central OR and the John Day Basin.

Models show the upper level trough to begin traversing southward and into the region by Thursday afternoon bringing with it southwesterly flow. Cooler temperatures will accompany the pattern shift as well as increased precipitation chances. Temperatures Friday will be nearly 10 to 15 degrees cooler than Thursday. Mountain showers are expected to begin after 8 PM Thursday night becoming widespread after 5 AM Friday. Model suggested 24 hour accumulations are between 0.01-0.05 in central OR (60-80%) to 0.05- 0.10 in through the Columbia Basin and foothills of the Blues (50- 70%), 0.10-0.25 inches along the eastern slopes and the Blue Mountains (60-80%) and lastly, 0.50-1 inch along the Cascade crests (50-70%). Models show the system to short lived bringing dry conditions behind it. Saturday and Sunday will see dry conditions return with temperatures continuing to cool.

Models are also indicating a surface level low will accompany the trough with a front slightly ahead of the system. This front will bring increased winds over the area starting Thursday night and continuing and increasing through Friday. With the trough digging farther south, pressure gradients across the region will tighten more over the central Cascades near the Gorge. The affected areas will be the Gorge, lower Columbia Basin and the foothills of the southern Blues. Raw ensembles show the likeliest location to be through the Gorge and the southern Blue foothills with 60-70% of the ensembles in agreement with up to 25-30 mph sustained winds and near 45 mph gusts. The remaining locations have a 50-60% chance of seeing 25 sustained winds and gusts near 35-40 mph. Much like the precipitation, winds will settle back to diurnal by Saturday morning. 90

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

VFR conditions will continue to prevail through TAF period. Light winds (under 10 knots) at all terminals through the period with the exception of some marginal gusts (up to 20 kts) developing at the BDN terminal after about 19z. Ceilings expected to lower after 19z for most terminals, however should remain at or above 20kft.

Preliminary Point Temps/PoPs

PDT 46 79 50 71 / 0 0 0 70 ALW 52 80 55 71 / 0 0 0 70 PSC 48 79 52 73 / 0 0 10 70 YKM 48 74 53 65 / 0 0 60 50 HRI 48 79 52 73 / 0 0 10 70 ELN 42 70 48 60 / 0 0 60 70 RDM 40 84 44 60 / 0 0 60 30 LGD 47 85 51 69 / 0 0 0 30 GCD 48 88 52 69 / 0 0 0 30 DLS 51 78 55 67 / 0 0 70 60

PDT WATCHES/WARNINGS/ADVISORIES

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