Weather Headlines
Wednesday December 19, 2001
The strong ridge/trough configuration of recent weeks relaxes temporarily.
It will reload again this weekend on the way to a transition to winter.
The weather system in the Midwest this morning is weak when compared to
recent standards. There is however, a decent cool air push behind it though
most of the precipitation with this is still liquid in nature. The gradual
trend down in temperatures continues as the pattern slowly changes. We have
seen near record warming out ahead of these systems early in December, now
the warming is not quite so robust. There won't be many changes yet to 5
day temperature departures as they remain above normal. Those changes may
start to show up by Friday. The next system to hit the West coast tonight
and Thursday looks more robust. Models continue to show the evolution of
this storm as the window to the soul of the long awaited pattern change. It
will be a sizeable wet weather maker this weekend and into Christmas. There
should be ample cold in the Northern U.S. for snow, but most still see
rain. It is a little early as to the potential of this storm with regard to
the East Coast for Christmas. It is my feeling at this early stage that the
I95 corridor is mainly a rain event with snow for the Lakes and Interior
NE.
Model consensus remains fairly strong with the evolution of the 6-10 day
period. We should at long last start seeing negative departures East of the
Rockies though I wouldn't call the numbers significant. It is significant
only when comparing to the last two months. Late in the period, all of the
models forecast a sizeable Western U.S. ridge and Eastern trough. This
brings the flow out of Canada and into the Plains. Now, attention turns to
source region of the air mass. It is clearly Canadian, but equally clear to
me it is not pure arctic. Thats why I dont think we are yet heading way
below normal. The coldest polar air is on the other side of the hemisphere.
It can come around if this pattern were to lock in for a while, but that is
after the first of the year. There is potential for serious cold early to
mid January, but right now its all potential. Until then, the gradual
step-down seems in order.
For the period Wednesday December 19 through Sunday December 23, expect the
following temperature trends:
Average 1 to 3-degrees below normal: Pacific NW, California, Intermountain
West?
Average 1 to 3-degrees above normal: Desert SW, Rockies ?
Average 4 to 6-degrees above normal: Plains, Ohio and Mississippi Valleys,
Gulf Coast, Southeast, Mid-Atlantic ?
Average 7 to 10-degrees above normal: Great Lakes, Northeast ...
Andy Weingarten, Meteorologist APB Energy / True Quote