I've excluded the technical explanation but if anyone is interested I can email it to them.
EAST-CENTRAL INDIANA WEATHER FORECAST
21JAN0618000WXF
Issued: 6:00 PM Saturday 21 January 2006
Forecaster: Dr. David L. Arnold
FORECAST DISCUSSION
Winter is coming back in a VERY big way, and the primary point I want to
make in this forecast discussion is that you need to be prepared for an
extended period of very cold weather along with the potential for a good
deal of snow.
And while the cold air is probably about a week away, which means we
still have some time left to get ready, this upcoming period will
represent the worst winter has to offer this season. In other words, it
WILL be colder than last December, which itself represented one of the
coldest winter months we’ve had in years.
In my last forecast I talked about a significant change in the
PERSISTENTLY warm pattern of late, in that we would begin to see more
frequent swings in temperature between well above normal, back to
normal, and this would represent the beginning of a transition back into
a very cold period that would begin at the end of January. Here is a
sample of afternoon high temperatures in Muncie for the week that
followed that forecast:
13th 53
14th 36
15th 41
16th 51
17th 53
18th 34
19th 54
If we compare the 30s highs to what occurred during the 48-hour period
before and after those days, there were 15-18 degree swings in afternoon
temperatures 4 times within a week!!!
And while I do want everyone to know I am not ducking the error I made
earlier this month (actually at the end of December) when I thought we’d
see more frequent swings in temperature all month long, and that these
swings would be from below to well above normal, and not from well above
to what turned out to be occasionally near normal, my overall forecast
for this winter has not changed since it was first issued last summer.
In other words, I still feel by the time we reach the end of winter, the
average temperature for the 90-day period will be below normal.
Not only has this forecast of a below normal average temperature been in
direct contrast with that issued by the National Weather Service (NWS),
my forecast for a very cold February is now also in contradiction with
that just issued (came out the 19th of January) by the NWS. If you are
interested in their forecast for us, go to:
http://www.cpc.noaa.gov/products/predictions/30day/off14_temp.gif If you believe this forecast of above normal temperatures for February,
then winter is over, and we can begin thinking about a little spring
cleaning. I just happen to disagree; and I happen to disagree very
strongly.
Again, we can only fairly judge a forecast for winter, and for the month
of February, AFTER the 28th of February has come and gone. However, I
will admit I was VERY surprised to see this latest NWS forecast of above
normal temperatures for East-Central Indiana for February. I am willing
to admit, well ahead of time, that they may be right and I wrong; but I
just don’t see it at this point. Not the way the hemispheric circulation
pattern is evolving, despite the development of a WEAK La Nina.
I also tried to make the point in my last forecast discussion that one
of the first signs we are beginning to see the manifestation of a
hemispheric circulation change is the development of powerful storms in
the vicinity of the Midwest region. And since that forecast we have seen
several.
No, we haven’t been bombarded with snow yet in East-Central Indiana,
although the last snow a couple of days ago, where accumulations ranged
from 2-4 inches, did catch many off-guard, and was a far cry for the “up
to 1 inch of wet sloppy snow possible” I heard promoted through various
outlets, there is now 4-6 inches of snow on the ground over much of
Michigan and northern Illinois after yesterday’s storm. And even though
we didn’t see the snow this far south, northern Illinois and Michigan
have also seen afternoon highs in the 40s and 50s lately as well. And
how about that wind last night??? Did that “sound” like a weak storm
coming through?
And finally I said that I still think, during this transition into the
heart of February’s cold that we would see the potential for some pretty
significant winter storms; and I still believe this to be true. In fact,
given the evolution of this pattern, there could be a longer than normal
period of winter storm potential as we transition into this cold pattern.
Now it’s just too far out to get into much detail here in terms of
individual storms, but some locations within the central and/or eastern
United States are likely to see some impressive snowpack buildups, with
maybe even near record amounts of snowfall for the month of February.
And while I am not saying we will be one of these locations, I cannot
rule us out either.
So, when will the cold arrive???
Well, the best answer right now is probably by the Monday the 30th;
however, that answer is to the question “when does the deep cold air
arrive.” What I mean by that is cold air over a great enough depth to
produce snow.
It is possible that the cold air may leak into our region as a shallow
layer before then, perhaps as early as next Friday, which means
afternoon high temperatures would only reach the 30s. And if we were to
see any precipitation in this cold air, especially at night before the
deep cold air arrives Monday the 30th, then we could see freezing rain
and sleet, which is something none of us wants again.
So the beginning of this cold period should begin about a week from
Monday, but I do want you to know that there will be a few days in
February in which temperatures could briefly pop up above freezing
should a powerful southern stream storm approach, but quickly return to
below normal shortly thereafter.
At the same time I expect to see some exceptionally cold air as well,
with below zero morning lows possible. Right now I think the coldest
period could begin at some point between about the 7th and 9th of
February, although we’ll have to wait a bit longer before such detail
comes into focus.
