581
FXUS06 KWBC 071907
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Mon September 07 2026

6-10 DAY OUTLOOK FOR SEP 13 - 17 2026

The 0Z ECMWF, GEFS, and CMCE ensemble model forecasts continue to predict an
amplified 500-hPa ridge over the North Pacific in the 6-10 day period, centered
to the south of Alaska in the GEFS and ECMWF models and over southeastern
Alaska in the Canadian model. Positive 500-hPa height anomalies extend across
the eastern Aleutians, Mainland Alaska, and Southeast Alaska in all ensemble
means. The manual height blend is based on the 0Z ECMWF, GEFS, and Canadian
model 500-hPa height forecasts, weighting the ECMWF ensemble mean greater due
to recent model skill. A trough is predicted over the western Aleutians in the
manual blend and most models, and a second trough is predicted to the southeast
of the North Pacific ridge, centered near the Pacific coast of the contiguous
United States (CONUS). While ensemble mean forecasts generally agree in
predicting a ridge and positive 500-hPa height anomalies across much of the
CONUS in the 6-10 day period, differences between models are apparent in the
evolution of the mid-level height pattern during the period. The GEFS and ECMWF
ensemble means both predict a shortwave trough over the northwestern CONUS on
day 6 and a ridge and positive 500-hPa height anomalies to the east of this
trough. The trough over the northwestern CONUS quickly deamplifies in all
models as positive 500-hPa height anomalies push westward. Later in the 6-10
day period a ridge is centered over the western half of the CONUS in the ECMWF
ensemble mean and over the central CONUS in the Canadian and GEFS ensemble
means. A trough and negative 500-hPa height anomalies push southward into the
northeastern CONUS in all models, with negative 500-hPa height anomalies
extending westward across the Great Lakes in the ECMWF ensemble mean.

The predicted amplified ridge over the North Pacific and associated positive
500-hPa height anomalies lead to likely above normal temperatures for the
eastern Aleutians, Mainland Alaska, and Southeast Alaska. Due to a predicted
trough over the northwestern CONUS early in the 6-10 day period and consistent
with the ECWMF forecasts, below normal temperatures are favored from the
northern Rockies eastward across the northern Plains into the western Great
Lakes region. Under generally positive 500-hPa height anomalies, above normal
temperatures are likely for a substantial portion of the southern tier and
eastern CONUS, including Southern California, the Southwest, the Southern
Plains, and most areas east of the Mississippi, excluding the western and
central Great Lakes region and northern Maine. Above normal temperatures are
very likely for Hawaii, consistent with the consolidation of ECMWF and GEFS
reforecast calibrated temperature forecasts.

The predicted location of the amplified ridge over the North Pacific and
southwesterly mid-level flow leads to elevated probabilities of above normal
precipitation for the Aleutians and most of Mainland Alaska, excluding parts of
the southeastern Mainland. Below normal precipitation is likely for Southeast
Alaska, under the ridge and consistent with most precipitation tools. A
predicted trough near the west coast of the CONUS and ridge location over the
central and eastern CONUS favor below normal precipitation for western areas of
the Pacific Northwest and elevated probabilities of above normal precipitation
for the Southwest, the Rocky Mountains, most of the Great Plains, the upper
Mississippi valley, Great Lakes region, and parts of the Northeast. Near normal
precipitation is favored over remaining areas of the southeastern CONUS, with
weak signals in precipitation tools and under a mean ridge for the period.
Above normal precipitation is favored for Hawaii consistent with the
precipitation consolidation.

The official 6-10 day 500-hPa height blend consists of 35% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 40% of Today`s 0z European Ensemble Mean
centered on Day 8, and 25% of Today`s 0z Canadian Ensemble Mean centered on Day
8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Average, 3 out of 5, due to good
agreement between model forecasts of the mean large-scale mid-level height
pattern, offset by uncertainty in the variable pattern during the period, and
differences among model temperature tools for the CONUS.

8-14 DAY OUTLOOK FOR SEP 15 - 21 2026

The overall predicted 500-hPa height pattern is relatively persistent into the
8-14 day period in ensemble model forecasts, with some eastward progression and
deamplification relative to the 6-10 day period forecast, as uncertainty
increases. The amplified ridge over the North Pacific progresses eastward into
northwestern Canada and deamplifies somewhat in all ensemble mean forecasts
during the week-2 period. A ridge and positive 500-hPa height anomalies persist
over most of the CONUS in the 8-14 day period ensemble means and the manual
blend, as a trough and negative 500-hPa height anomalies expand over the
northeastern CONUS. Mid-level height anomalies deamplify across the CONUS later
in the 8-14 day period, as uncertainty and ensemble spread increases. Weak
positive 500-hPa height anomalies are forecast across nearly the entire CONUS
in the week-2 manual blend, with near average 500-hPa heights predicted near
the northern California coast and over the Northeast.

Above normal temperatures continue to be likely for the eastern Aleutians,
Mainland Alaska, and Southeast Alaska, under positive 500-hPa height anomalies.
Above normal temperature probabilities are elevated for the western CONUS from
the coast to the Rocky Mountains and southern High Plains, consistent with most
model forecasts and a westward shift of the mean location of the ridge from the
6-10 day period. Under a predicted trough later in the week-2 period, below
normal temperatures are favored from the northern Plains across most of the
Great Lakes region into northern areas of the Northeast, consistent with the
consolidation. Above normal temperatures are likely for the southeastern CONUS,
consistent with the temperature consolidation. Most model tools agree on a
forecast of high probabilities of above normal temperatures for Hawaii.

The location of the ridge over Southeast Alaska in week 2 continues to favor
above normal precipitation for the eastern Aleutians and most of Mainland
Alaska, excluding the southeastern Mainland, while below normal precipitation
is favored for Southeast Alaska, under the ridge. Below normal precipitation
continues to be slightly favored for parts of the Pacific Northwest, consistent
with the precipitation consolidation. Continued troughing near the west coast
and southerly mid-level flow favors above normal precipitation across most of
the western CONUS, outside of the Pacific Northwest, consistent with model
precipitation tools. Precipitation signals are less consistent for the eastern
CONUS, with a variable circulation pattern and differences among model
forecasts. Above normal precipitation is slightly favored for the southeastern
CONUS and the Eastern Seaboard, consistent with the precipitation consolidation
and an autoblend of precipitation tools. Above normal precipitation is favored
across Hawaii, consistent with all model forecasts.

The official 8-14 day 500-hPa height blend consists of: 35% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 40% of Today`s 0z European Ensemble Mean
centered on Day 11, and 25% of Today`s 0z Canadian Ensemble Mean centered on
Day 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Below average, 2 out of 5, due to
general agreement among dynamical models on the 500-hPa height pattern, offset
by differences among model temperature forecasts and weak precipitation signals
over the eastern CONUS.

FORECASTER: D Collins

Notes:


The notation for the categorical forecast indicated on the maps is
the same as that in the tables: A-above   N-near normal   B-below

The temperature map shows regions with > 33% chance of being warmer
(orange, "A"), colder (blue, "B"), or close to (gray, "N") normal.
Labels on the shaded lines give the probability (> 33%) of the more
likely category (B or A). Probability of N is always < 40%.

The precipitation map shows regions with > 33% chance of being
wetter (green, "A"), drier (tan, "B"), or close to (gray, "N")
normal. Labels on the shaded lines give the probability (> 33%) of
the more likely category (B or A). Probability of N is always < 40%.

In the southwest and other climatologically dry regions - there will
be a greater than 33.3% chance of no precipitation and occasionally
even a normal (i.e. Median) value of zero - especially during the dry
seasons.  In such cases a forecast of near normal is effectively a
forecast of little or no precipitation.

The climate prediction center uses 1991-2020 base period means as
reference in the climate outlooks.

The next set of long-lead monthly and seasonal outlooks will be released on
September 17.


Analogs to the 5 day mean observed pattern centered 3 days ago (D-3)
for the region from 20N to 70N latitude and 175E to 60W longitude
include the 5 day periods centered on the following dates:
20050909 - 20220918 - 20190918 - 20240819 - 20140823


Analogs to the 7 day mean observed pattern centered 4 days ago (D-4)
for the region from 20N to 70N latitude and 175E to 60W longitude
include the 7 day periods centered on the following dates:
20240820 - 20050908 - 20190918 - 20220918 - 20240913


6-10 DAY OUTLOOK TABLE
Outlook for Sep 13 - 17 2026

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  N    B     OREGON      N    B     NRN CALIF   N    N
SRN CALIF   A    A     IDAHO       B    A     NEVADA      N    A
W MONTANA   B    A     E MONTANA   B    A     WYOMING     B    A
UTAH        A    A     ARIZONA     A    A     COLORADO    A    A
NEW MEXICO  A    A     N DAKOTA    B    A     S DAKOTA    B    A
NEBRASKA    N    A     KANSAS      A    A     OKLAHOMA    A    A
N TEXAS     A    A     S TEXAS     A    N     W TEXAS     A    A
MINNESOTA   B    A     IOWA        N    A     MISSOURI    A    A
ARKANSAS    A    N     LOUISIANA   A    N     WISCONSIN   N    A
ILLINOIS    A    A     MISSISSIPPI A    N     MICHIGAN    N    A
INDIANA     A    A     OHIO        A    N     KENTUCKY    A    N
TENNESSEE   A    N     ALABAMA     A    N     NEW YORK    A    A
VERMONT     A    A     NEW HAMP    A    A     MAINE       N    A
MASS        A    A     CONN        A    A     RHODE IS    A    A
PENN        A    N     NEW JERSEY  A    N     W VIRGINIA  A    N
MARYLAND    A    N     DELAWARE    A    N     VIRGINIA    A    N
N CAROLINA  A    N     S CAROLINA  A    N     GEORGIA     A    N
FL PNHDL    A    N     FL PENIN    A    N     AK N SLOPE  A    A
AK ALEUTIAN A    A     AK WESTERN  A    A     AK INT BSN  A    A
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    A    B



8-14 DAY OUTLOOK TABLE
Outlook for Sep 15 - 21 2026

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    B     OREGON      A    N     NRN CALIF   A    A
SRN CALIF   A    A     IDAHO       A    A     NEVADA      A    A
W MONTANA   A    A     E MONTANA   N    A     WYOMING     A    A
UTAH        A    A     ARIZONA     A    A     COLORADO    A    A
NEW MEXICO  A    A     N DAKOTA    B    N     S DAKOTA    B    N
NEBRASKA    N    A     KANSAS      N    A     OKLAHOMA    A    A
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    A
MINNESOTA   B    N     IOWA        B    N     MISSOURI    N    N
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   B    N
ILLINOIS    N    N     MISSISSIPPI A    A     MICHIGAN    B    N
INDIANA     N    N     OHIO        N    N     KENTUCKY    N    N
TENNESSEE   A    A     ALABAMA     A    A     NEW YORK    N    A
VERMONT     B    A     NEW HAMP    B    A     MAINE       B    A
MASS        N    A     CONN        N    A     RHODE IS    N    A
PENN        N    A     NEW JERSEY  N    A     W VIRGINIA  N    A
MARYLAND    N    A     DELAWARE    N    A     VIRGINIA    A    A
N CAROLINA  A    A     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  A    A
AK ALEUTIAN A    A     AK WESTERN  A    A     AK INT BSN  A    A
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    A    B

                           LEGEND
TEMPS WITH RESPECT TO NORMAL     PCPN WITH RESPECT TO MEDIAN
A - ABOVE   N  - NEAR NORMAL     A - ABOVE   N - NEAR MEDIAN
B - BELOW                        B - BELOW

THE FORECAST CLASSES REPRESENT AVERAGES FOR EACH STATE. NORMAL
VALUES - WHICH MAY VARY WIDELY ACROSS SOME STATES - ARE
AVAILABLE FROM YOUR LOCAL WEATHER SERVICE FORECAST OFFICE.

FOR ADDITIONAL INFORMATION SEE MESSAGE FXUS06 KWBC - ON AWIPS AS
PMDMRD.

$$