Herb's Ski Weather Forecast

							Herb's Ski Weather Forecast

Written by Herb Stevens-The Skiing Weatherman
Sunday, 15 March 2009 11:49

We are headed into the stretch run of the season in much of the United States, and overall,
base depths and the weather pattern are looking pretty good. Easter comes along on the 12th
of April, and it looks as though the resorts that typically point toward that weekend (when it is in
April) as a closing date should be able to make it this year. While a few resorts in the southern
Appalachians are going to pack it in after this weekend, which is right about on time for their
closing date, base depths are still strong at the other resorts in the region, and many of them
will be trying to make it to April.

The weather pattern will lead itself to colder air remaining in control of the pattern over the
northeast United States over the next 2- 3 weeks and likely beyond. In the wake of some recent
rains the surface conditions have firmed up, and in spite of a big effort on the part of the region’s
mountain crews, some fresh snow would really help to soften things up.

 There is the potential for some light snow on the back end of a cold frontal passage later this
week, but the next threat of significant snow will have to wait until an upper level low gets
strongly re-established over the East about a week from now. Once that trough gets locked in, a
series of global indicators suggest that it will dominate right into early April, which bodes well for
the preservation of base snow leading up to the Easter holiday.

 In the West, the past two to three weeks have been quite snowy, as a trough off the coast has
been sending ashore one moisture laden system after another. The storms were a little warmer
than most would like, so snow levels have been bouncing up and down a bit, leading to some
moister surface snow, particularly in the lower elevations. The jet stream flow responsible for
those storms has lifted to the north, and for the near future, the place to go for fresh snow in the
West will be the Cascades of Washington and Oregon, as well as the mountains of Idaho and
western Montana.

 This morning’s jet stream pattern across the country is not particularly exciting...for now. In a
transitional month like March, periods of tranquility don’t generally last too long, due to the
ongoing battle between residual cold to the north and growing warmth over the southern
latitudes.

 The strongest jet stream flow is located over the northwestern U.S., and that is what is driving
the moisture ashore that is in the process of turning into some sizable snowfall amounts in the
areas I mentioned in the first paragraph. Some of that short wave energy will press through the
upper Midwest by midweek, bringing an end to a warming trend that has converted packed
powder to more a springlike surface in Minnesota, Wisconsin, and Michigan. Further east, the
week will start with high pressure over Ontario that will press east and bring a couple of nice
days to New York and New England. The snow will be firm in the morning, but tend to soften up
during the day...the sunniest trails, and the sunniest areas, like Bromley in Vermont and
Cranmore in New Hampshire, are your best bets for soft snow until some fresh snow returns.

 A cold front will start to approach the East on Wednesday. That front will be a rather slow
mover, and I think a couple of waves of low pressure will move along the front as it presses
southward. Those waves will serve to enhance the showers that will accompany the frontal
passage. Colder air will slowly undercut the moisture, and the rain will gradually change to snow



                                                                                                 1/3
Herb's Ski Weather Forecast

Written by Herb Stevens-The Skiing Weatherman
Sunday, 15 March 2009 11:49

late Wednesday and Thursday. That is when a light accumulation could occur from northern
Pennsylvania northward to the Adirondacks and the mountains of northern New England. In a
best case scenario, post-frontal snow could amount to a few inches of new snow...not a dump,
but enough to help restore a softer surface.

 Now, in terms of a more substantial snowfall, the northern Rockies will be the place to be this
week, although some light snow will fall in the upper Midwest late in the week, as short wave
troughs cycle through the region on their way to re-establishing a large upper level trough over
the East next weekend.

 The East will have to wait until that new trough takes shape before any sort of a significant
snowfall can come their way. That trough will be rather persistent next week, due to the
reluctance of an upper level block over northeastern Canada to move. Blocking patterns in
March are fairly common, and when both the Arctic Oscillation and North Atlantic Oscillation are
headed for negative territory, the odds are that the trough won’t be going anywhere, and cold air
will be reinforcing it every few days. That is the sort of set up that enhances the potential for a
more significant surface storm...a short wave dives into the long wave trough, feeds off the
warmth to the south, turns up the coast on the east side of the trough, and “voila” you have
yourself a coastal storm.

 Now, there is a subtle change to the pattern from what we have seen in the past several
weeks, when the lion’s share of the snow has fallen in the coastal plain and into northern New
England. The next trough will be located a little further west than its predecessor, and I think
that will focus the snow a little further west...from the central and northern Appalachians into the
southern Lakes. Resorts in those areas have seen some mild weather and rain of late, but if
they hang in there, they are likely to see some late season snowfall.

 While the trough gets established in the East, a ridge will start to pop in the West, which will
bring an end to the heavy snow in the northern Rockies next weekend. By late in the month, I
think that the wavelengths of the upper level features will shorten, which will allow for both the
East and the West to be dominated by troughs capable of producing new snow...if that
happens, warmth will dominate in the middle, which could bring a swift end to the season in the
Midwest....that won’t happen for at least one more weekend, though.

 As I mentioned earlier, I think that in the East, the prospects for favorable weather leading to
the Easter holiday are good, as the trough is likely to hold until at least early April. Typically, it is
hard to get to consistently warm weather in the spring when a La Nina is on its’ last legs, which
is the case this year. The analog years that keep popping up, 1951 and 1956, both had cold
weather (with respect to normal) for a good portion of April, and I think that is what we are
looking at over the next month or so.

 Temperatures should certainly be cold enough to do a good job of preserving the snow on the
trails for the foreseeable future. A late season snowfall or two seems to be in the cards, as well,
as the pattern reverts to a persistent eastern trough. In the West, there is certainly enough snow
to sustain the season into April, although in the southern Rockies, where snowfall has been
below normal this season, the high sun angle could result in a faster shrinking of open terrain



                                                                                                    2/3
Herb's Ski Weather Forecast

Written by Herb Stevens-The Skiing Weatherman
Sunday, 15 March 2009 11:49

than one would typically see in late March/early April. Regardless of the weather in your favorite
part of the country, time is running out, so make plans to make more turns before the garden,
the boat, or the golf course beckons in a voice that you can’t ignore.




                                                                                             3/3