MARCH-MAY 2011 90-DAYFORECAST
330 PM EST Tue. Mar. 1, 2010
Atmospheric patterns, 700 MB and 500 MB height anomalies, statistical
data, various models, observed cases from past winters and sea surface
temperatures in the tropical Pacific where used in this forecast.
A cold episode conditions continue across the tropical Pacific with
Sea surface temperatures near the equator in the eastern and central
Pacific ocean are 1 to 2 degrees C below normal from about 160Ee to
120W. Below normal sea surface temperatures extend from 20N to 20S
latitude over much of the eastern
Pacific. Sea surface temperatures from 120W to the South American
coast have warmed during the last month from below the -1.5 C anomaly
to near the normal. The subsurface ocean heat content from near
equatorial average temperatures in the upper 300 meters continues to
be below normal in the east Pacific, while above normal anomalies in
the west Pacific have expanded eastward. The large scale atmospheric
circulation over the tropical Pacific ocean continues to indicate a
cold episode. Convection remained enhanced over Indonesia and
suppressed over the western and central equatorial Pacific. Low level
easterly trade winds are enhanced over the west Pacific, as are
westerly wind anomalies in the upper levels over the western and
central Pacific.

The NAO index is positive and is forecast to trend towards neutral by
day 10 and remain neutral to slightly positive through day 14. The NAO
is negative and is forecast to remain negative through day 14. The AO
is positive and is forecast to remain positive through day 14.

The large area of anomalously cool sea surface temperatures are
forecast to have a significant impact on the large scale atmospheric
circulation throughout the tropical Pacific. This is expected to
influence the atmospheric circulation pattern over North
America. Forecasts from most models indicate a cold episode to last at
least through the spring,
Below normal temperatures are forecast across the Northwest, the
northern Rockies and the northern Plains. The probability of below
normal temperatures across this area is 57 percent. Above normal
temperatures are forecast for most areas below 35N. The probability of
above normal temperatures across this area is 57 percent. The
remainder of the nation is expected to be near normal with no
significant deviation from normal climatology.
Above normal precipitation is forecast for the Northwest and the
northern Rockies. The probability of above normal precipitation across
this area is 57 percent. Below normal precipitation is forecast for
the southern Rockies, the central and southern Plains, the lower
Mississippi Valley and the Southeast. The probability of above normal
precipitation across this area is 57 percent. Above normal
precipitation is forecast for the Northeast, the northern mid-Atlantic
and into the Ohio Valley. The probability of above normal
precipitation across this area is 57 percent. The remainder of the
nation is expected to be near normal with no significant deviation
from climatology.
Jim Munley Jr.
http://www.jimmunleywx.com