As high pressure passes above, there will be a respite in the precipitation over the majority of Southwest Washington and Northwest Oregon today, to begin with.
Even though temperatures in the Hood River Valley are still at or below freezing, temperatures in the lowlands are above freezing and are expected to stay so through Thursday.
Rain will return to the region tonight as the storm system moves back ashore, and snow levels will gradually decrease back to the Cascade passes.
As the rain advances into the middle Columbia Gorge and nearby valleys, there is a chance of light freezing rain in isolated spots.
Due to the arrival of other low-pressure systems from the Gulf of Alaska/Western Canada, temperatures will be below average moving into the holiday weekend.
This setup can produce some lowland snow over the weekend and into the beginning of next week.
From now till Thursday, you may. As weak high pressure moves northeastward through the forecast region, there will be a break in the precipitation for most of the forecast area today.
A few patches of clearing overnight resulted in fog formation in the affected regions practically immediately.
Some of the fog was thick earlier in the night, with vsbys less than 1/4 mile away, but the fog looks to be rising into a low stratus deck. Therefore, it seems safe to lift the Dense Fog Advisory for the southern Willamette Valley for the time being.
As precipitation begins to fall this evening, the warm air in the atmosphere will cause snow levels to rise quickly because there is no genuine cold air in place in the Columbia Basin in advance of this storm.
This will likely be mostly a low elevation rain/mountain snow event, with snow levels dipping to somewhere between 3500 and 4000 feet as precipitation rises during the night.
A winter storm watch was issued for areas of the Columbia River Gorge and Hood River Valley on the east side of Mount Hood for tonight and Wednesday. Still, the latest information indicates that temperatures are rising and that the likelihood of freezing rain/mixed precipitation is diminishing.
We were careful in not dismissing the watch before it even went into force. Still, it looks more probable that the Gorge and lower areas of the Hood River Valley will stay just a touch too warm to get any significant winter precipitation from this storm.
QPF seems to be marginal for warning quantities of snow in the upper Cascades as well - an advisory would be more suitable for the 6 to 14 inches of snow forecast.
Because there is still a chance that temperatures in the Hood River Valley will continue below freezing - particularly with the new snow cover above 500-700 feet - we will keep the watch for the time being and let the day shift take one more look at it.