It’s cold out there! At 9am temps in the mid-upper 20s across all of the metro area except those spots exposed to the “milder” east wind coming out of the Gorge. The east wind will gradually die back this evening, but I don’t see any mixing south wind (if any) until after the rain begins. So no one below 1,000′ (most of us) will see a dramatic warming today. As mentioned last night, if rain was arriving right now, or earlier, we would have a widespread freezing rain event west of the Cascades…it’s all about timing. So where is the rain? Save this link to radar to watch it during the day. You generally want a “green” area to get rain all the way to the ground. Those are echoes above 20dbz. It’s trying to move onto the central Oregon coast at this hour. All coastal sites have jumped well above freezing, so no freezing rain out there today.
A change this morning in timing though…all our mesoscale models have slowed down rain arrival in the valley yet again; this is very good news. Here is the 1:30pm RPM rain/snow outlook
and 1pm WRF-GFS
Both show no (other than a sprinkle) rain arrival in the valleys until after the noon hour. They DO still hint that some of those isolated valley locations in the Coast Range could see freezing rain (Vernonia, Manning, etc…) to start. But with the forecast later arrival of rain, that decreases further the chance that we see anything frozen on roads here in Portland.
I did notice one more thing on morning models/maps. This system is so weak, there is a possibility we don’t get ANY mild mixing wind today either in the Valley or the Columbia River Gorge. I think it’ll just be in isolated spots. So high temps may only be around 35 and we just sit there tonight (assuming solid cloud cover). And in the Gorge there is plenty of dry air left to allow some evaporational cooling as the precip starts. Could still be icy out there late this afternoon or evening when the rain moves in.
The layer of cold air over us west of the Cascades is incredibly thin. 32 degree and warmer temps are only around 700-800′ up! By the time you get up to 2,000′ it was 46 degrees over Salem! Now that is a good inversion.
Chief Meteorologist Mark Nelsen