textproduct: Pendleton

KEY MESSAGES

1. Dry and warm conditions will persist through the week with near record temperatures possible

2. Breezy to windy through the gaps today

3. Midweek pattern shift will bring chances mountain showers and thunderstorms

DISCUSSION

Current satellite shows some upper level clouds lingering over the area with a few isolated pockets of mid level clouds over the Kittitas Valley. CLouds are clearing out of central OR leaving them with mostly clear skies. This will assist with keeping overnight temperatures a bit warmer in the mid to upper 40s (70-90% confidence).

Models show the upper level ridge to still be overhead keeping the area under warm and dry conditions. Temperatures will be 10-15 degrees above seasonal normal increasing to nearly 20-25 degrees above normal by Tuesday. Highs Sunday and Monday will be in the upper 70s to low 80s with 80-90% of the NBM raw ensembles in agreement. Tuesday however, ECMWF. GEFS and NBM ensembles all show temperature to be nearing the 90s with 80-90% probabilities. Looking at in house data, the mean max temperatures for Pendleton is 70 degrees, Tri- Cities is 76 degrees, Walla Walla is 71 degrees. These temperatures are well below the expected temperatures the ensembles are suggesting and could possibly break a few temperature records.

Models shoe an upper level shortwave will make its way across the forecast area today showing another day of breezy to windy conditions through the mountain gaps. 70-80% of the NBM raw ensembles show Kittitas Valley and the Gorge seeing sustained winds between 20-30 mph with gusts of 40-45 mph today starting after 2 PM and persisting through 9 PM. After the front passes, winds will turn to typical diurnal winds under the ridge.

Tuesday night models show an upper level system beginning to make its way into the region. Clusters show the variance between the models to be the timing and positioning of this system. Some models want to bring the system into the PacNW as a trough, some want to bring it a bit farther south of the region while others want to bring it under the region. Regardless of the scenario, each one leads to the breakdown of the ridge which will in turn lead to southwest flow aloft ushering in unstable conditions to the region allowing for the chances of thunderstorms. Looking at the NBM 12 hour probability of thunder, there is a 20-30% probability of thunderstorms forming over the OR Cascades as well as over the eastern mountains by Wednesday. Not only are there chances of thunderstorms, but there is also a 20-40% of mountain showers as well.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

VFR conditions will persist through the forecast period. Breezy conditions will occur across all TAF sites after 18-21Z with sustained winds of 10-20 kts with gusts 20-25 kts and persisting through 04Z. CIGs will be primarily 25 kft with no VIS issues.

FIRE WEATHER

High pressure will persist through midweek with dry and warming conditions. A shortwave today will bring breezy west to northwest winds today, with strongest winds through the mountain gap areas of the Kittitas Valley and the Gorge. A breakdown in the ridge Tuesday will result in an increasing instability through central Oregon and the eastern mountains where 20-30% probabilities of thunderstorms may occur by Wednesday. This afternoons RHs will be mostly in the teens to mid 20s, with single digits in central Oregon with these RHs returning Tuesday afternoon.

Preliminary Point Temps/PoPs

PDT 78 46 76 48 / 0 0 0 0 ALW 79 50 77 51 / 0 0 0 0 PSC 84 50 81 51 / 0 0 0 0 YKM 82 47 80 50 / 0 0 0 0 HRI 81 48 79 49 / 0 0 0 0 ELN 74 44 75 46 / 0 0 0 0 RDM 80 38 82 46 / 0 0 0 0 LGD 83 43 78 45 / 0 10 0 0 GCD 89 42 84 47 / 0 0 0 0 DLS 76 48 82 53 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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