Last Days of February 2012; A February 2011 Redux?

February 17, 2012

Long range maps are looking quite interesting with next weekend’s cool shot of air looking colder.

In the short-term, pretty easy forecasting…lots of mountain snow the next 24 hours and then mainly dry Sunday with another system bringing in the rain again on President’s Day.  The rest of our 7 Day forecast is just rainy and milder through next Friday (a week from today).

Now on to the long range…This morning’s ECMWF was significantly colder with a modified arctic air mass dropping south out of Western Canada next Saturday night and Sunday.  The depth of the cold air forecast on that run was very similar to what we saw last February 25th/26th.  Interesting to note the dates are exactly the same this year.  ECMWF showed 850mb temps down as low as -11 over our area with 500mb heights and 500-1000mb thicknesses a very close match to last year.  If the ECMWF is correct, we WILL have a late season arctic blast with highs only in the 30s for one or two days, just like last year.  Here’s the 500mb chart at the coldest point; classic arctic outbreak upper level pattern:

The GFS has been much milder with a similar pattern though.  It was slightly colder on this evening’s 00z run. 

Both models have pushed back the timing of colder air by about 36-48 hours from what they showed maybe 3 days ago.  Not sure if that’s significant, but something to note.  The GFS would just be cold snow/rain showers and not an arctic blast, just a chilly late winter spell. 

Could we get snow to sea level with what these models are showing?  Sure…but of course moisture would need to line up with the cold air blah, blah blah…the usual.

I did check the coldest days last winter for the record:  Salem bottomed out (at 12z on the 25th) with -9.5 deg. temp at 850mb, 526dm 500mb height and 513 thickness (brrr!).  Spokane was -17.5, 527 height, and 507 thickness within 12 hours of that time.

Since it’s still 8-9 days away, I’m not too worried about my “calling off winter”  post…yet.  The ECMWF would make me look like a fool maybe, no problem with the GFS.

Chief Meteorologist Mark Nelsen


12z Ensemble Charts

February 17, 2012

Too busy to talk long range weather this afternoon (I have all 5 evening shows), but here are the 12z 850mb ensemble charts from the GFS and ECWMF.

As always, click for the full-size image…

I haven’t started rocking in the fetal position in the corner of the weather center yet based on the 12z ECMWF…yet.

Chief Meteorologist Mark Nelsen