JUNE-AUGUST 90-DAY 2009
400 PM EST Mon. June 1, 2009
Atmospheric patterns, 700 MB and 500 MB height anomalies, statistical
data, various models, observed cases from past summers and sea surface
temperatures in the tropical Pacific where used in this forecast.
Sea surface temperature anomalies along the equator in the central
Pacific are currently near average neutral from about 160 E to the
South American coast. Neutral conditions are expected to prevail
during June.

A blend of modeling and analogs are being used in this forecast. Those
analogs strongly account a developing El Nino during this summer and a
cold PDO. While the Pacific is changing the overall cold PDO should
hold along with the developing El Nino may lead to cooler temperatures
in the East.

All long lead models are in agreement is forecasting above normal
temperatures across the West with the exception along the coast. This
is due to cooler than normal sea surface temperatures. There are
however, slight differences as the SMLR indicating below normal
temperatures across the northern Rockies, the northern Plains and
portions of the Southeast. The probability of above normal
temperatures across this area is 57 percent. Below normal temperatures
are forecast for the upper and middle Mississippi Valley. The
probability of below normal temperatures across this region is 56
percent. What could go wrong is that El Nino has more of an impact
than expected. The result will be colder temperatures from the Plains
eastward. The remainder of the nation is expected to be near normal
with no significant deviation from normal climatology.
Below normal precipitation is forecast across the Rockies to the West
coast. The probability of below normal precipitation across this area
is 56 percent. Above normal precipitation is forecast across the Great
Lakes, the Northeast and the northern mid-Atlantic. The probability of
above normal precipitation in this region is 56 percent. Another area
of above normal precipitation is the gulf coast. This is due to
tropical disturbances moving across the area. The probability of above
normal precipitation across region is 56 percent. The remainder of the
nation is expected to be near normal with no significant deviation
from climatology.