A Chilly Night

April 14, 2009

Snapshot Looks like a chilly night on the way tonight.  A very cold airmass is overhead, dewpoints have fallen into the 30s, and skies are partly cloudy to mostly clear.  I drove down to Lamb Elementary in N. Salem for a school visit today and noticed a few peach tree orchards in bloom.  I have a feeling anything lower than 30 would be very bad, so hopefully most spots will just touch the freezing point.  For those of you concerned about freezing, it's good news that we'll only see one night of the really cold temps.  A slightly warmer airmass is over us tomorrow night and then it's on to a cloudy and warmer one Thursday night.

Showers were a bit more intense than I had expected today, but at least we did see plenty of sun inbetween the showers.  Looks like snow briefly stuck down to around 1,000' overnight, but then showers tapered off later in the the night, minimizing any accumulations.

No change to the forecast thinking the next few days.  All models give us some rain as a warm front brushes us Thursday night and Friday.  Then much stronger ridging takes hold for the weekend and early next week.  There is a subtle trend in the 12z ECMWF and now the 00z GFS for a slightly weaker ridge Sunday-Tuesday.  I'll ignore the 18z GFS…it looked almost "hot".  850mb temps on Sunday and Monday on the 00z GFS are still up around +13 to +14, which prompted us to put an 80 degree high in the 7 Day Forecast.

Mark Nelsen


Return of the Snow

April 13, 2009

Drew and I traded shows tonight so I was on at 8pm and he was on…about right…now.  I'm blogging from home.  I ran into snow on the side of the road and slush on the road just slightly above 1,000' this evening on the way home.  At 1,200' the shady parts of the road were white.  I have a trace of slop/slush/snow on everything outside my home right now at 1,000'.  So one last gasp of winter with the snow level maybe dipping to around 1,000' at times in heavier showers overnight. 

Looking at the maps, this probably really is it for the cold weather…warm spring temps are definitely coming back for awhile later this week and early next.  I see 850mb temps are forecast by various models to be up around +12 to +15 deg. C. by next Monday.  That's 80 degree territory, maybe even a notch or two warmer with easterly flow in the 2nd half of April.

Not much else to say, except put any snow totals you get in the comments tomorrow morning.  If some of you in the hills get more than 1/2", let the rest of us know!

Mark Nelsen


A Spring Forecast

April 10, 2009

610day.03 Today's 7 Day forecast is a bit more reasonable for April, at least to me.  We have some moderate to heavy rain one day, showers on two others, mostly cloudy on a 4th day, and 3 days of mostly sunny with warmer temps.  Now that's a real nice mix for mid month.  It's been well advertised that it'll be a very wet Easter Sunday.  No changes to that forecast.  At least a good chunk of tomorrow will be dry though.

The map above is one I've shown you before…it shows the 500mb height deviation from average during the 6-10day forecast period.  That would be the middle of next week through the following weekend.  Models are pointing towards higher 500mb heights and ridging in general over the West Coast and western USA.  Our forecast temps around 70 might be a little low for next Thursday and Friday, but I notice the ECMWF and GFS were a bit different.  There's time early next week to adjust the numbers.  The main point is that we can expect drier and warmer weather later next week.  That would be AFTER some chilly air later Sunday through Tuesday…Mark Nelsen


Mid Week Doldrums

April 8, 2009

Snapshot  Drew Jackson and I have been working in here together this evening, and it just seems like one of "those" evenings.  The weather is boring, with no significant extremes of any sort on the way.  Of course the big change today was the sudden cool down.  We went from a high of 76 yesterday to 59 today.  I see Gov't Camp dropped 24 degrees in one day.  We've quickly moved from June back to April.

Not much on the horizon except a nice strong frontal system for Easter Sunday.  It sure looks juicy…definitely an indoor day.  I can remember some Easters that were warm and sunny.  I think there was one around 1990 or 1991 that was around the 80 degree mark just like 3 or 4 years ago.  Those are nice ones, then we have the usual slop most years…Mark Nelsen


June Weather Ends

April 7, 2009

Snapshot  It's been quite a wild weather ride the last 5 days.  I took Friday off to do a one-night camping trip near Estacada.  That was really cold.  I couldn't believe folks were camping in tents when the morning low was 31 degrees out there early Saturday morning.  But the temperature jumped almost 30 degrees in 3 days (by Monday), as if we went from February to June over the weekend.  A high of 51 sounds brutally cold now.  I was pleased with our forecasts for the last few days.  When I left Thursday we forecast 60, 70, 75, 68 for Saturday through Monday.  Looks like all except today were within 3 degrees.  I think this points out how well we've been forecasting "heat waves" the last 5 years.  I don't think we've missed a single significant warm up (or summer heat wave) in a long time.  Models seem to do quite well with the 850mb temp forecasting, which leaves the meteorologists to deal with local terrain effects and other factors that affect the final high temp down here at the surface.  Some day we'll get just as good with the ending of ice and snow storms, but I'll be an old man (maybe 50-60) by then.

Short term, a nice surge of marine air is taking over tonight.  I see low clouds have arrived at Eugene already.  Our model and the WRF-GFS show a thick push that seems to get broken up by the much cooler air arriving in the upper atmosphere tomorrow.  That's why they show skies turning partly cloudy.  Our 60 degree forecast accounts for this.  Otherwise a strong push in early April would make me think more like 55 degrees for a high.

I don't have any other deep thoughts for the next 7 days or so.  Looks pretty typical, actually a bit on the cool side, through the period.  I did get a chance to plant carrots, spinach and lettuce.  The garden is now going…slowly…Mark Nelsen


End of Ratings

April 2, 2009

Snapshot  Last night (Wednesday) marked the end of our ratings period.  Normally we don't take time off during the periods when Nielsen collects demographic info about who is watching our station.  Generally those are the months of November, February, May.  I don't think I've taken time off in those three months for 10-15 years.  However due to the expected change to digital TV in February, that period was moved to March.  Of course we all know what happened; Congress extended the deadline to mid June.  So now that the "book" has ended, I'm going to take tomorrow off.  And, due to the forecast, I'm taking Monday off now as well!  Seems appropriate so I can get outside and enjoy the June-like temps on the way.

No changes in thinking tonight.  GFS has come even closer to the ECMWF, delaying the arrival of energy from the southwest until at least midweek.  This appears to be a classic "warm" spring setup of a split flow being slow to let moisture back in here.  The models are playing catch up a bit.  This means a heck of a nice period of sunshine and unusually warm temps for early April.  Easterly flow kicks in Saturday, but the atmosphere is pretty chilly, so 60 is the best we'll get.  Strong easterly flow Sunday may keep some spots in the 60s, but I have a feeling plenty of us will make it to 70.

To me Monday sure appears to have the signature of a "surprise" warm day.  Easterly flow dies down during the day while 850mb temps soar up to 10-14 deg.  That gives 75-80 degrees at PDX according to my reliable (and freshly updated!) forecast chart.  Of course that's REALLY hard to believe after a long period of high temps around 50 degrees.  That's why the chart is so helpful in these situations…it's very objective.

Enjoy the warmer weather…Mark Nelsen


Finally! Some Spring on the Way

April 1, 2009

I got pretty busy tonight staring at tons of numbers.  My April 850mb "magic chart" that I like to use in the warm season is the last that hasn't been updated since 2000.  So that involves looking up lots of numbers and putting them into a spreadsheet.    Anyway, that didn't leave time for anything else.  So here's a brief synopsis:

1.  A real juicy cold front comes through the next few hours.  Radar is all lit up with heavy precip. to the west…should be a soaker tonight.

2.  GFS has definitely moved into agreement with the ECMWF on the weekend/early next week pattern.  A deep upper-level low moves towards the California coastline, pushing a warm airmass up over us.  Now the GFS has 850mb temps peaking out around +10 C Sunday afternoon.  The ECMWF was exactly the same, and continued the warmth through Monday.  Those temps plus easterly wind in April could push us to 75-78 degrees according to the numbers I was working on tonight for the chart.  Hard to believe since we've been so cold.  Drew and I went somewhat conservative with temps, holding Sunday's high to 70 degrees.  Most likely we'll go warmer in tomorrow's 7 Day…probably for Monday too.  Get ready for some REAL spring weather Saturday through Monday, maybe a bit beyond!

Mark Nelsen