799
FXUS06 KWBC 081921
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Tue September 08 2026

6-10 DAY OUTLOOK FOR SEP 14 - 18 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 all ensemble means. Positive 500-hPa height anomalies
extend across the eastern Aleutians, Mainland Alaska, and Southeast Alaska. 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 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. Ensemble means predict a series of shortwave
troughs progressing over the northwestern CONUS before the start of the 6-10
day period and weak troughing over this region on day 6, with a ridge and
positive 500-hPa height anomalies over the eastern CONUS. Later in the 6-10 day
period, positive 500-hPa height anomalies increase over the northwestern CONUS
in all ensemble means, while a trough and negative 500-hPa height anomalies
push southward into the northeastern CONUS.

The predicted amplified ridge over the North Pacific and associated positive
500-hPa height anomalies lead to likely above normal temperatures for all of
Alaska. Due to a predicted troughing over the northwestern CONUS early in the
6-10 day period and consistent with the ECMWF 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 eastern 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.
Teleconnections to the North Pacific ridge favor below normal precipitation for
western areas of the Pacific Northwest. Dynamical model forecasts favor
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 16 - 22 2026

The overall predicted 500-hPa height pattern is relatively persistent into the
8-14 day period in ensemble model forecasts, with some evolution of the pattern
and deamplification relative to the 6-10 day period forecast, as uncertainty
increases. The amplified ridge over the North Pacific progresses eastward into
Southeast Alaska 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 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 parts of 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. Dynamical model
precipitation tools and the consolidation continue to favor above normal
precipitation across most of the western CONUS, outside of the Pacific
Northwest and parts of California and Nevada. 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 most of the eastern CONUS, excluding parts of the northern central
CONUS and the Florida Peninsula, 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: 30% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 45% 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:
20050910 - 20220919 - 20240819 - 20190918 - 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:
20050908 - 20240820 - 20220918 - 20190918 - 20240913


6-10 DAY OUTLOOK TABLE
Outlook for Sep 14 - 18 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       N    A     NEVADA      N    A
W MONTANA   B    A     E MONTANA   B    A     WYOMING     N    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    A     KENTUCKY    A    A
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    A     NEW JERSEY  A    A     W VIRGINIA  A    A
MARYLAND    A    A     DELAWARE    A    A     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 16 - 22 2026

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    N     OREGON      A    N     NRN CALIF   A    N
SRN CALIF   A    A     IDAHO       A    A     NEVADA      A    A
W MONTANA   N    A     E MONTANA   N    A     WYOMING     A    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    A     W TEXAS     A    A
MINNESOTA   B    N     IOWA        B    A     MISSOURI    N    A
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   B    N
ILLINOIS    N    A     MISSISSIPPI A    A     MICHIGAN    B    N
INDIANA     N    A     OHIO        N    A     KENTUCKY    A    A
TENNESSEE   A    A     ALABAMA     A    A     NEW YORK    N    A
VERMONT     B    A     NEW HAMP    N    A     MAINE       B    A
MASS        N    A     CONN        N    A     RHODE IS    N    A
PENN        N    A     NEW JERSEY  N    A     W VIRGINIA  A    A
MARYLAND    A    A     DELAWARE    A    A     VIRGINIA    A    A
N CAROLINA  A    A     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    A    A     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

                           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.

$$