One last “Snow Day”

February 28, 2007

Snapshot_29One last tough forecast as we wrap up meteorological winter tonight.  Cold showers still streaming onshore this evening.  We are now in the coldest airmass of this cold/wet episode.  850mb temps bottom out around -8 deg. C. in the next few hours and then rise to -4 or so by tomorrow afternoon.  A line of showers moved over southern Columbia county and Clark County for an hour or so this evening, giving a nice dusting in those spots.  With such a cold airmass overhead, any other significant showers overnight should drop a dusting or more.  I see the top of our transmission tower in the West Hills (it’s the one that’s farthest north in that array up there) is down below 29 degrees at 1800′.  That’s cold!
So we have colder air, but less moisture the next 10 hours, compared to this morning.
With that in mind, I figure a trace to 1" anywhere in the metro area is a good bet.  A bit of melting snow that freezes on roads can make a mess as well.
Overrunning slightly warmer air tomorrow midday-afternoon should give us more stratiform rainfall (solid light rain).  The snow level will be very slow to rise, so unless we get heavy precip, I think most likely we’ll see an inch or more 1,000′ or so and maybe 2-3" up above 1,500′ by late tomorrow before the snow level finally reaches 2000′ by tomorrow evening.
A building upper-level ridge Friday brings us plenty of warmer rain, then the ridge shoves the rain north of us later Saturday and Sunday.  The 00z GFS has some light precip over us Sunday, but that is unlikely with such a strong ridge.  +6 deg. 850mb temps in early March CAN send temps well into the 60’s.  Assuming we get to at least partly cloudy skies, 63 shouldn’t be too hard to hit.  Hard to believe after the cold temps lately, but it’s a bit overdue…Mark