A Colder Week Ahead!

January 30, 2014

We may have the first widespread cold period since mid December coming for next week across the Pacific Northwest.  Models have been advertising a cool northerly flow for next week for quite a few days, and there have been hints of an “arctic intrusion” of some sort too.  What’s the difference between that and an arctic blast?  Not sure, but it doesn’t look nearly as cold as what we saw back in December.  And this time, as of tonight at least, there doesn’t appear to be any moisture associated with the cooler air for snow.

The 00z GFS and 00z ECMWF both agree on a gradually cooling air mass from Sunday onward.  The ECMWF is especially aggressive with 850mb temps down around -10 at 850mb over our area.  At the same time we get gusty east wind through the Gorge…brrr, if so winter isn’t done yet!  Take a look at the strong easterly pressure gradient on the ECMWF too:

ecmwf_apcp_f132_nw

I lowered the 7Day forecast high temps into the 30s as a result.  If it was November or December and it hadn’t been cold yet this season, I’d say it’s time to wrap the pipes etc…  But we’re still in winter and there’s nothing to “prepare for”.

Here is the 00z GFS ensemble chart:

tseries_850t_000-384_Portland

and the 12z ECMWF ensemble chart:

tseries_850t_000-360_Portland

They both seem to be a little on the cold side; the blue lines are the operational runs we get the maps and output from.  The red is the average of all the ensemble members.  There is a clear signal that once we get to about next weekend we go to a wetter westerly flow and temps back around normal.  Since it’ll be mid-February by that time, my gut feeling then is that next week will be the last chance for a many-days-long cold spell this season.

Other than the impending colder weather, the theme for this winter remains the same for the next 8+ days…DRY.

Chief Meteorologist Mark Nelsen


ECMWF Weekly Maps

January 30, 2014

Here are the next 4 weeks of weather action from last night’s ECMWF run.  What does it mean?  Looks like a wetter period in the middle of the month and MAYBE some false spring weather with ridging returning near the end.  That’s after a very chilly week next week:

500za_week1_bg_NA

500za_week2_bg_NA

500za_week3_bg_NA

500za_week4_bg_NA