Weather Headlines
Tuesday November 20, 2001

*** Models converging on an increasingly stormy pattern. The question still
to be answered is when the arctic air arrives.***

     The current cool down in the East is very transitional with warmer air
to return by the end of the week. The pattern has clearly changed as the
jet stream has been suppressed Southward. In the short (and medium) terms,
things should turn stormier, but not necessarily colder. In fact, latest
charts indicate a healthy ridge to build late this period over the SE U.S.
in response to a trough developing over the Rockies. This opens the Gulf of
Mexico up in a moisture sense, but any winter snows look to be confined to
the extreme Northern tier of states. Much needed rains may fall from the
Plains to the East Coast by the weekend in areas that have been parched
this Fall. In terms of temperatures, 5 day averages will not depart
significantly from normal the rest of the week though the trend late in the
period will be for a warmer East and a cooler West.

     I have been consistently forecasting colder air (along with most
others) in the 6-10 day period for a couple of weeks now. It has been slow
in developing and the cool down now in the East would hardly be considered
significant unless it is compared to the record warmth of the last couple
of weeks. The pattern I foresee going into early December is colder
relative to normal in the West and warmer in the East. Specifically a storm
track from the SW into the Plains and NE will set up allowing for generous
rain (with snow North) to develop. Arctic air is moving to this side of the
pole and pooling in NW Canada. Now, a mechanism to drive it SE is needed.
One of the tools used that I occasionally refer to is the North Atlantic
Oscillation (NAO).  Most winter forecasts have predicted this as largely
negative this season which is a robust signal for cold air in the East. It
has been negative the last two weeks though in fairness its reliability as
a signal gets much higher in December for cold. I find it interesting to
note the signal is expected to go weakly positive next week. Bottom line
for the period is I see a continuation of a cold bias with the Western
trough and a warm bias in the vicinity of the Eastern ridge. We may also
see a significant storm move through the country during the period, but
again I look for snow to be confined to the North.

For the period Tuesday November 20 through Saturday November 24, expect the
following temperature trends:

Average 1 to 3-degrees below normal: Gulf Coast, Southeast, Mid-Atlantic?

Average 1 to 3-degrees above normal: Ohio and Mississippi Valleys, Great
Lakes, Southern Plains, Pacific NW, California?

Average 4 to 6-degrees above normal: Desert SW,  Rockies, Intermountain
West, Central and Northern Plains?

Andy Weingarten, Meteorologist  APB Energy / True Quote