First Frosts Possible

Providing a heads-up concerning potential weather events that may have impact is the foundation of The Weather Café®️.  Such is the case today.  Get your morn’n beverage ready.

Pleasant fall afternoon today, once the fog clears away in the usual locations.  The weekend ahead will present Saturday as mostly cloudy & dry, with showers or rain moving in overnight into Sunday.  Most of the precip will fall south of Salem (~2 tenths), with enough precip to wet the roads north all the way into WA.  Temps will be mild, yet a few degrees cooler each afternoon this weekend.

Monday the 23rd looks dry, as the PNW will between systems.  A notable shift in the overall pattern will begin Tue Oct 24.  The Low pressure system we have been mentioning for over a week now will arrive Tue, but from a different direction, if you will.  Backstory: long-time Patrons know that we pay close attention to High pressure domes that form over the Yukon region with a center pressure at 1040 mb or higher.  Well, current model solutions indicate a Yukon High of around 1032-1038 mb developing Tue, then moving south in a classic ‘winter’ type motion.  Agreed, not a '1040 dome', but close.  The Low we have expected will form along the cold air boundary of that High on Tue, ushering in rain and COLDER temps overnight Tue and through Wed.  We are not labeling this an ’Arctic Event’ - not at all - just the first push of chilly interior Canada air of fall 2023.  (That Low will not move in from the west, nor track south off the coast - which was the earlier model scenarios.)  Stay with us - - -

Wet and chilly Wednesday, with snow levels dropping enough to coat the top of the Cascades.  The system will move east rapidly, ushering in chilly air for Thu.  Right now, although close, we do not see a frost on Friday morning (temps in the low 40s to upper 30s possible west side).  But wait, there’s more.  A secondary push of colder air is modeled to more over the PNW later on Friday, so expect dry but chilly temps for the afternoon, turning much colder overnight Fri.  FROST is likely Saturday & Sunday morning, Oct 28,29 - with subfreezing temps on both sides of the Cascades.  There is an outside chance for a weak Low to form along the southern OR coast for showers there, and snow showers possible across eastern OR.  Maybe.  Farther north, fog may form in places, which may limit how cold it gets.  We will update this, if the models verify the chilly pattern next week.

An east wind out of the Columbia River Gorge will not be severe, but it will get going as the weekend of Oct 28,29 ends.  (At this time, we do not foresee a wind issue for the Fraser Gap.)  Dry to start the Oct 30 - Nov 3 week.  Frosty morning possible Monday, although the air mass will begin to warm, with an offshore flow.  Rain may move in from the west by late Thu Nov 2 or on Fri Nov 3.  The chilly dry period will be over.  Expect a wet, mild first weekend for November 2023.  

Bottom line: first frosts of the fall may be on the way.  Use this heads-up to prepare for a few nights of subfreezing temps.  NOT super cold, but definitely cold enough to nip sensitive patio plants or freeze an outdoor water line.