1:30pm Monday, March 6:
It's been a brutal stretch of winter weather...let me count the ways:
1. 7th coldest January on record (7.7 degrees below normal),
including 5 below zero low temperatures.
2. Above normal snowfall in December and January, with 14.3" and
17.7" of snow, respectively.
3. 8th coldest February on record (6.4 degrees below normal).
Combined, January & February rank as the 4th coldest in our 100 years
of Lancaster records.
4. February 5th's crippling ice storm left 46,000 without power.
5. February 13th's snowstorm dropped between 11 - 21 inches of
snow on the county.
6. February's total snowfall of 27.6"...the 5th snowiest February
7. The coldest start to March on record with the first 5 days
averaging 14.5 degrees below normal.
Are we done yet?
Not quite. The good news is that global patterns are shifting in a
way that favors more frequent appearances of milder weather here, and
the increasing sun angle means that even a 40-degree day can feel
surprisingly warm. The current Arctic air mass, now moving off the New
England coast, will be the last deep plunge of Arctic air that we'll
see for a while. Westerly flow across much of the US and southern
Canada serves as a sort of dam that will lock true Arctic air over
central and northern Canada. The result may be high temps that reach
the 50-degree mark on three of the next six days...Saturday (not a
for-sure), Monday & Tuesday (likely). Low-level easterly flow on
Friday will bring cool maritime air and clouds off the Atlantic...and
perhaps some spotty drizzle over parts of southeastern PA. A glancing
shot of Canadian air will make Sunday feel cooler with highs in the
low 40s and wind chills in the 30s. Otherwise, the next six days will
be rather uneventful and relatively pleasant, compared with what we've
experienced the last nine weeks.
Looking into mid-March, a return of a higher amplitude pattern from
March 12 - 16th will likely result in a return of colder-than-normal
conditions for a few days. A storm off the Pacific early next week
will approach here from the south around March 12 or 13th and,
depending on storm track, could bring us some wet snow or cold rain.
Climatology favors a snow-rain mix in Lancaster and heavy wet snow in
the mountains of PA. Of course, storm track and timing (day versus
night) are important factors that can't be determined at this time.
Beyond that, I expect conditions will be quite variable with
occasional 50- and 60-degree days, but also a few relapses into
below-normal conditions. There's tremendous snow pack across Canada,
the Great Lakes have near-record amount of ice cover (92% as of 3/6),
and modest cross-polar flow continues to drive bitter Arctic air
into northern and central Canada. While this Arctic air is currently
blocked from penetrating deep into the US, a full-latitude pattern
amplification--which is quite possible sometime in March or early
April--could bring a final shot of near-record cold...and perhaps a
final winter storm.