Marine Weather and Tide Forecast for Milton-Freewater, OR

FXUS66 KPDT 230928 AFDPDT

Area Forecast Discussion National Weather Service Pendleton OR Issued by National Weather Service Spokane WA 228 AM PDT Wed Apr 23 2025

SHORT TERM
Today through Friday...

Key Points

1. Dry and warm temperatures through Thursday

2. Precipitation to return to region Thursday afternoon through Friday.

Current nighttime satellite shows little to no clouds over the region tonight. There will be a slight pattern shift as an upper level trough will continue to swing towards the region before shifting southward and undercutting the region. This will allow for some wrap around moisture to push into the region from the south. However, models do show the influence of the system to be weak. This will still allow some precipitation to return to the OR Cascades and portions of the eastern mountains before becoming widespread by Friday.

Dry and warm conditions will continue through today and much of Thursday ahead of the weak pattern shift. Models show the region to continue to be under the influence northwesterly flow aloft as an upper level trough continues to push towards the region.
Temperatures will continue to be warm even under the influence of the low as warm air advection pushes warm air from the south into the region. 70-80% of the raw ensembles show temperatures today to be in the mid to upper 60s through the Basin, Gorge, Yakima Valley and portions of the foothills of the northern Blues while central/north central OR, Kittitas Valley and the foothills of the southern Blues will see low to mid 60s. THursday 60-80% of the raw ensembles show temperatures in the lower elevations seeing upper 60s to low 70s while the mid elevations like central OR seeing mid 60s. Friday temperatures are expected to increase a few degrees leaving 40-60% of the raw ensembles showing the Basin could see temperatures in the mid to high 70s, 30-60% shows the foothills of the S & N Blues will see upper 60s to low 70s and 50-80% show N central/central OR will see the mid to high 60s.

As for the precipitation, models show the upper level system to begin as a trough as it continues to slip southward. The leading edge of the system will allow for some precipitation to make its way across the far southern portion of the Cascades in the CWA with 30-50% of the raw ensembles only showing 0.01 inches of rain to begin Thursday evening. By Friday models show the upper level system to become a bit more of a closed low and it will move a bit farther southeast undercutting the region. This will allow for the wrap around moisture to begin to influence the eastern mountains and steadily move northward with the precipitation. 80% of the raw ensembles show 0.01 inches of precipitation through central OR and the eastern mountains, 30-50% for 0,01 inches along the foothills of the N & S Blues, 30-50% for the WA Cascades and less than 30% for the Basin.

LONG TERM
Saturday through Wednesday...Ensemble guidance in pretty good agreement on the synoptic pattern through the period.
Main story continues to be a broad cutoff low that will pass to our south, followed by a warming trend heading into next work week as high pressure builds in overhead. As models continue to bring this cutoff low to our south, the precip forecast continues to trend downward. As a result, thinking that the greatest impact from this system will be gusty winds, especially across the Cascade Gaps, Foothills of the Blues, and the Grande Ronde Valley.

The center of this system will already be to our south by Saturday morning, with most models pinning it around the central Sierra Nevada range. This is not a particularly ideal setup for onshore moisture advection into our forecast area, but given this system’s slow progression, wraparound moisture will make for persistent PoPs across the Oregon Cascades and eastern mountains, with the wettest day on Saturday. Still, NBM probabilistic guidance is only suggesting about a 40-50% chance for QPF over a quarter of an inch for the eastern mountains and around a 70-80% for the Cascade crests across central Oregon. Not a particularly impressive system in terms of precip, but that is to be expected with the low taking a more southerly track than what models had initially anticipated. The chance for thunderstorms has also decreased as favorable dynamics once again fall to our south, but still cannot rule out isolated storms (20-30% chance)
across the eastern mountains thanks to favorable orographic flow via wraparound moisture.

Otherwise, precip chances fall off after Sunday once the system fully exits the forecast area, with ensemble consensus being that of ridging moving in Monday onward. As this low moves in and we transition between systems, expect a couple of gusty days for our usual wind-prone areas. In fact, NBM probabilistic is already suggesting a 70-80% chance for wind gusts to exceed 45 mph across the Kittitas Valley, Columbia River Gorge, and the foothills of the Blue Mountains on Saturday and Sunday as this low (and the ridge trailing it) invite a strong cross-Cascade pressure gradient. And given how much models have us warm up next week (approaching the 80s across the lowlands by the end of the period), would not be surprised if we see several wind advisories over the weekend. Evans/74
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