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Riddle me this: You name a storm "the blizzard of 2010" that’s not
really much of a blizzard...then what do you name a storm that IS a
blizzard in the winter of 2010?
The storm shaping up for late Tuesday into early Thursday may turn
into a bonafide blizzard along the I-95 corridor from DC to Boston.
What begins as a moderate clipper system across the Midwest Tuesday
will bomb into a monster Nor'easter along the New England coast by
late Wednesday and Thursday. Whereas the lowest barometric pressure
with the weekend storm was a modest 990mb, this explosive system may
deepen below 970mbs...which could make for wind gusts approaching
hurricane force in coastal areas. The amount of snowfall with this
storm is tricky, because the location (how far off the coast) of the
bombing low pressure system is somewhat uncertain. Initially, our
snowfall will be light to moderate from mid-afternoon Tuesday into
the
first half of Tuesday night; this first part of the storm should
bring
us 2 to 6 inches of snow. As the coastal low develops, however, a
deepening fetch of Atlantic moisture will be thrown back inland--it's
this feature that could drop another 4 to 12 inches of snow on
Wednesday...or it could set up east of our area with little
additional
accumulation here. My sense is that we will get at least a few inches
of snow from the coastal low...let's say another 3 to 6 inches.
Combining these two "parts" of the event and you get my first-call
estimate for the Lancaster area of between 6 and 12 inches.
While this storm is not likely to produce the 30-inch
amounts of last weekend's storm, it will generate much more
wind...perhaps double or triple the wind impact of the last storm. If
so, this system would cause extreme drifting and scattered power
outages. The worst of the wind will be along and east of the I-95
corridor with sustain winds of reaching 40mph and gusts to 60 or 70
mph. Farther west in the Susquehanna Valley, I expect 20 to 40 mph
winds; so in the worst case we might experience near-blizzard
conditions. This wind forecast counts on the coastal low bombing near
the coast, and so a development farther out to sea would spare us the
extreme winds and heavy snowfall. Therefore, the ultimate outcome is
a
bit uncertain...check back here for daily updates.
Storm
Outlook map (Issued: 1:00pm Monday)
Here's a link that reveals one computer model forecast of this
monster storm deepening off the east coast on Wednesday evening. Canadian
60-hour forecast.
Streaming
Video (Issued: 2:00pm Monday)
Noon Sunday:
High pressure is now firmly in control, so a beautiful period of
cold, dry mid-winter conditions are on tap through Monday night.
Daytime highs will only reach the upper 20s today, then increase to
near 32 degrees on Monday and Tuesday. Overnight lows will range
from the single digits in the typical cold spots to mid-teens in
town. Daily snow melt on the roads will cause many slick spots
during the nightly refreeze; and while the snowpack won't melt
much, it will settle/compact a bit in the coming days (since such
light, fluffy snow is mostly air). With another storm on the way,
however, we will likely be adding to the snowpack soon.
The next storm is very different from the previous storms of this
winter. It's an Arctic clipper system that will track from the
Northern Plains to the Midwest then into the northern Mid-Atlantic
by Tuesday night. Gulf moisture will be limited this time, so
initially the system will yield only a moderate snowfall (perhaps 5
to 10 inches) across parts of the Midwest. When the clipper reaches
the coast, however, the pattern favors it "bombing" (that's
meteorologist speak for "strengthen rapidly"). Atlantic moisture
will
be tapped and heavy, wind-drive snow may then fall from eastern PA
into southern New England. This would place Lancaster on the western
edge of the heavy snow. The range on possibilities here are: we get
a few
inches from the clipper but very little from the bombing low
to....we get bombed by the deepening coastal with another
12-inch-plus snowfall! Regardless of the amount of snow received
here, this upcoming storm promises to generate
much higher winds than the storm we've just experienced. (Wind is a
function of
pressure gradient, and Saturday's storm only reached a minimum
pressure of about 990mb whereas Wednesday's storm is forecast to
drop to 970mb!) If this should verify (remember, it's just a
forecast, not a given), then the modest drifting of Saturday's storm
would pale in comparison to what would occur with this upcoming
system. To make matters worse, the potential for 20 to 40 mph winds
(with higher gusts)
would not only blow the new snowfall, but also our current fluffy
snowpack. Should all of these ideas come to fruition, then a REAL
Blizzard would result from eastern PA into southern New England! Now
that I've said that, please remember that it's all potential and
conjecture at this point... Check back here tomorrow for an update,
because the players will then be stepping onto the field (kickoff
will be Monday night in the Midwest) and, thus, I'll be able to
better analyze the match-up in order to release my "line" for the
game. (Sorry for all the puns...I couldn't resist. Enjoy the game
tonight!)
5:00pm Saturday:
A final wrap-up entry on this most remarkable storm. Snowfall
reports across Lancaster county range from 16 to 26 inches, with 20
to 24 inches most common. (Many thanks to all of our great snowfall
reporters!) Millersville's official snowfall was 24 inches (1.45"
of liquid equivalent), which equals the other two great February
storms on record...February 1983 and February 2003. The January 1996
Nor'easter continues as the top dog in terms of snowfall (30
inches), while the Blizzard of March 1993 remains the
ultimate "storm of the century" with its crippling wind-blown
snowfall (that stretched from GA to ME), record low barometric
pressures, and massive drifts (to 10 feet in places!). Still, this
winter goes into our record books as having the record December
snowfall (16 inches) AND a record-tying February snowfall (24
inches). It's been a great run...can you even fathom a third "major"
(12+ inch) event this winter???
The jet stream pattern remains in a favorable configuration for
generating another storm. Of course, creating a major snow storm in
the East requires that many ingrediants come together just
right...which is exactly why they are so rare. Remember, Lancaster
averages only four 12-inch-plus snow storms per decade...and
we've just had two in a single season! Therefore, it is indeed hard
to imagine that we'll get another major storm this season...however,
the computer models are bullish on an Arctic Clipper bombing out
along the coast of Delmarva on Wednesday. What the models are
depicting would become a REAL blizzard for New England, and it could
even drop a moderate to heavy wind-driven snowfall on eastern PA.
Still, a lot can change in the coming days and it's premature to get
too excited about the next storm when there's still snow on the
roads from the last system. But I'll keep an eye on it, and provide
daily updates. Until tomorrow, wishing you a warm and relaxing
evening...and many rich memories of this great storm! --Eric
11:30am Saturday:
Wow, what a storm! Snow lovers in Lancaster county really couldn't
ask for more. The axis of heaviest snow set up about 40 miles
farther north than expected, so the band of heaviest snow fell in
areas between Lancaster and Baltimore rather than between the Mason-
Dixon Line and Washington, DC. Many reports from across the county
are now nearing (or exceeding) 24 inches, although northern areas
are generally running
a several inches less (I've had about 20 inches at my place in
Manheim Township). Of course, measuring the snowfall accurately is
very problematic--any measurement near a house or other large object
will be affected by windflow around the object, and of course a lot
of the snow from your roof is blowing down as well. So take a hike
around your yard and take several measurements in more open areas to
create an average (then submit your report using the link below!).
The final band of accumulating snow is now descending across the
county, so the moderate snow will taper to light snow and flurries
in the next hour or so. An additional inch is possible in some
places (especially across
the south) but at this point it's tough to measure new snowfall
versus blown snow. Regardless of the final numbers this storm ranks
right up there with the grand storms of February 2003 and January
1996. And on the heels of the record-breaking December 19, 2009
storm, it is all that more remarkable. Of coure, many national media
outlets continue to promote the "Blizzard of 2010" even though I
have yet to see any official reports of actual blizzard conditions!
Winds in our area really didn't come close to the three hours of
sustained at 35mph needed for a blizzard. Of course, parts of NJ
(perhaps Atlantic City) or northern Delmarva may still experience
near-
blizzard conditions today... Anyway, it's just one of those hypish
(is that a word?) things that really bugs me--we have official
definitions for various storms and impacts, yet they just don't seem
to matter when someone wants to create a sensational narrative for
the national news or an Internet site. I guess we should just start
calling any wind-driven rain storm from the south a "hurricane"
regardless of the whether the storm actually meets the official
criteria! (Sorry for the rant...I'm feeling a bit punchy after three
sleep-deprived nights.)
View reports from: Feb 6th | View statewide reports from NWS co-op
observers.
Submit your snowfall report
Looking ahead, Arctic air is now filtering in on that north wind
you feel outside and tonight will drop into the teens, even single
digits in the typical cold spots. Some sunshine will return Sunday
and Monday, but with highs only in the upper 20s to near 30 there
won't be much melting (although the fluffy snowpack will compact
quite a bit, since it's actually mostly air). Another powerful jet
stream system will then dig our way with another potential snow
event for the mid-week. Check back this afternoon for a preliminary
look at this storm. (If you still haven't yet had enough snow!)
7:20am Saturday:
Thanks for all the snowfall reports! It's great to see that some
other people were up all night besides me (and PennDOT)... Anyway,
your reports reveal the sharp gradient across the county, that we've
come to expect this winter, ranging from 12 - 16 inches north of
Route 30 to between 18 - 21 inches south of Route 30. I would expect
another 3 to 8 inches of snow (although determining new snowfall
versus blown snow will be difficult) before things taper off from
late morning into the early afternoon. The long band of snow
stretching across southern PA will gradually sag southeastward as
the upper-level low, now over WV, pivots across VA and out to sea
this afternoon. 10 to 20 mph winds will shift more out of the north
this afternoon, so blowing/drifting will continue. Temperatures will
hold nearly steady today, then drop into the upper singles to mid
teens tonight as winds gradually decrease.
4:30am Saturday:
Okay, I've slept on it for an hour... I'm bumping my accumulation
forecast to 18 to 24 inches across the southern portion of the
Susquehanna Valley! See the revised Storm Outlook map below. Reports
are coming in of 16+ inches in a few spots south of Route 30, so
some of these locations may approach 2 feet of snow and perhaps a
couple spots nearer the Mason-Dixon line get 26 or 28?! If so,
this would make it the largest snowfall since February 2003 (24
inches fell) or perhaps even January 1996 (30 inches). Areas near
and just north of the Turnpike are looking
at 10
to 18 inches, with a sharp dropoff in snowfall amounts going
northward towards I-80. Winds continue at 10 to 20 mph with some
gusts to 30mph; this is not enough to officially make it a Blizzard
here, but it's still a crippling storm and certainly many people
will be using the "B word" to describe it here. Anyway, the coastal
low is now deepening and beginning to track east into the Atlantic.
So the large east-west band of snow, now across PA, MD, DE, and
NorVA will begin to thin from the top (north) southward, while dry
air tries to entrain in from the south. You can best view this trend
with the
regional radar. So I expect the snow to taper off across
northern PA during the mid-morning and then taper off across the
southern counties during the midday and early afternoon. BTW, given
the magnitude of this storm....I want to return to something I
pointed out a couple of days ago. Experiencing the December 19th
snow storm (~ 16 inches) AND now this storm (20 - 24 inches in
city?) in the same winter season is truly amazing and historic. Only
three times before, in over 80 years of records, have there been two
12-inch-plus events measured in the Lancaster (city) area. Take lots
of pictures and soak up the grand experience you have been gifted
today!
Storm
Outlook map (Issued: 4:30am Saturday)
View reports from: Feb 5th | Feb 6th | View statewide reports from NWS co-op
observers.
Submit your snowfall report This is a very difficult
storm to measure given the blowing and drifting snow. Your best bet
is to get away from "wind tunnels" and into an open section of your
yard and take several measurements to average out. I had been using
my back deck (normally an ideal snow board for moderate storms), but
I'm experiencing drifting around the house and snow blowing off the
roof...so I'll be post holing through my yard to get the final
measurement!
11:30pm Friday:
I just measured 6.5 inches at my house (Manheim Twp.) and, as I'm
sure you've noticed, the snow is becoming noticeably drier and the
winds are picking up. Northeasterly winds of 10 to 20mph, with
higher gusts, add blowing and drifting to the mix overngiht through
Saturday afternoon. The heaviest snow is on tap the next 6 to 8
hours, before a gradual taper-off develops (from north to south)
late morning into early afternoon. With snow totals now in the 5 to
8 inch range across the county (and over a foot in the mountains of
southcentral PA) it's beginning to look like this storm will exceed
the big snowfall we experienced on December 19, 2009! Of course,
measuring this snowfall will be more difficult since the wind will
be blowing the snow around (whereas there was minimal wind with the
December storm). Anyway, it's sure looking like there will be spots
across southern PA that may receive 20 or even 24 inches. Perhaps
that 18 - 24 inch band on my Storm Outlook map needs expanded a bit
farther northward? Let me sleep on that for a bit... Enjoy the
storm!
9:00pm Friday:
Just returned from a family hike in the snow--what a gorgeous
evening! Fresh, sprakling, peaceful snow falling and the smell of
wood-burning fireplaces in the air...absolutely wonderful. Here's a
snapshot
of my happy gang enjoying the evening. :-) Anyway, all systems are
go with this storm and the snow is already piling up across the
region. There are several reports of 4 inches across the southern
half of the county, and the next heavy band is now developing over
northern MD and heading our way. Model guidance has become more
steady the last 12 hours with all models finally on board with the
idea of a 10+ inch snowfall across our region, and twice that in the
areas of maximum snowfall (which I continue to feel will be an west-
east band roughly parallel to the Mason-Dixon, but centered about 20
miles south of the state line). If you want to see/experience the
heaviest snow, then set your alarm for around 2:00am and head out
for a hike. I think I will!
Here are the links to view a full listing of reports submitted to
the MUWIC and NWS co-op reporters from around the Commonwealth.
7:30pm Friday update:
Temps have dropped below freezing and the first band of heavy snow
is now moving across Lancaster county from the south. I received a
report from a recent MU MET grad in southern York county--he
received 3 inches in one hour as this band passed over last hour!
While I can't guarentee this amount of snow in your location, the
band will bring our first good "pop" of accumulating snow this
evening. This type of storm is "all about the bands"...places that
received several of these heavy bands are where snow totals will
approach 20 inches. While you can view these bands developing over
the region on the NWS
radar composite (look for the dark green and yellow bands), they
are best viewed locally on the WGAL radar (although there are some false "holes" in the
precip over parts of York and Lancaster due to ground clutter
algorithms). These bands typically form, progress, and then begin to
fizzle over the course of an hour or two (think of summertime
thunderstorm evolution on radar); they are dynamic and somewhat
random features, so while they are easy to observe, they are hard to
forecast. Check back for another update around 10:00pm or so.
3:30pm Friday update:
Whew! Is it Spring yet? I'm just glad this storm is going to miss our
area....
(Just kidding!)
Okay, the storm is developing pretty much as expected. Surface
temps got a bit warmer (upper 30s) today than expected--further proof
that this is not a classic front-end loaded system, but instead a
complex hybrid "jump" storm. Expect a few surprises, in terms of how
this storm pans out and the snowfall it produces. Lots of crazy
numbers are being thrown around. I heard the NWS is calling for 22 -
30 inches in Washington, DC--that could bust by a fair amount! First,
it's been snow there for a few hours with no accumulation due to warm
low-level temps. Furthermore, the first half of this storm, which is
being feed by a subtropical plume, will be rather warm aloft and not
so ideal for snow crystal growth aloft. As a result, I expect the
first half of the storm to yield rather wet snow at a 10:1 ratio;
this
holds for everyone in the region, both here in PA and down in MD, VA,
NJ. As the secondary low develops overnight, the atmosphere will cool
both at the surface and aloft. Surface temps will drop into the 20s
overnight while temps aloft (where the snow flakes are being
generated) will cool to around -15C, which is ideal for crystal
growth. As a result, this evening's wet snow will turn into a
moderately dry snow by daybreak Saturday...and so the latter part of
the event may yield snow at a ratio closer to 15:1. Anyway, I think
VA
may underperform (relative to the NWS snowfall forecasts), and I
continue to believe that the axis of maximum accumulation is from
Garrett county MD east along I-68 and across northern MD and northern
Delmarva (per my Storm Outlook map below). The southern counties of
PA
will be oh so close to the max snow.... I'm sticking with the 10 - 18
inch forecast here, but I won't be surprised to receive a few reports
of 20" across the southern counties of PA. Convective banding is
always the wild card with these Nor'easters--get a band over your
head
and you get a couple hours of 3-inch snow per hour, whereas if a band
sets up just upwind of you, then you get robbed of moisture and get
much less snow than you otherwise would have. These are things we can
watch for on radar later tonight and early Saturday.
I'm going to shift into more of a blogging mode this evening, so
I'll be making numerous entries here throughout the storm. I invite
you submit your snowfall reports (below). Enjoy, and be safe out
there!
Streaming
Video (Issued: 1:45pm Friday)
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