June-August 2007
90-Day Forecast
600 PM EST Mon. June 4, 2007
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 temperatures along the equator are currently below normal
from 140W to the South American coast. Sea surface temperatures were
observed slightly above normal throughout most of the central
equatorial Pacific. ENSO conditions are currently neutral. The upper
heat content in the eastern equatorial Pacific is below normal. Most
indicators show that anomalies in the east-central Pacific should
become negative during the month. At present, it is not expected to
have a significant impact the Northern Hemisphere circulation during
the next month.
NAO is currently negative and is forecast to remain negative during
the first half of June. The PNA is positive and is forecast trend
towards negative during the same period. The 500-HPA pattern across
North America is expected to consist of a ridge in the West and a
ridge in the western Atlantic.
Above normal temperatures are expected across a large portion of the
nation. A greater chance of above normal temperatures will be in the
Southwest and over the Southeast where chances are 60 percent.
Elsewhere the chances for above normal temperatures is 55 percent.
The only area that are expected to experience near normal temperatures
will be the West coast.
Below normal precipitation is expected across the Southwest and the
central and southern Rockies. The probability of above normal
precipitation is this region is 57 percent. Below normal precipitation
is also expected across the central gulf coast and the Southeast. The
probability of below normal precipitation in this region is 57
percent. Above normal precipitation is expected across the extreme
northern Plains and northern New England. The probability of above
normal precipitation across this region is 56 percent. The remainder
of the nation is expected to be near normal with no significant
deviation from climatology.