601
FXUS06 KWBC 161902
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Wed September 16 2026

6-10 DAY OUTLOOK FOR SEP 22 - 26 2026

Dynamical models are in good agreement regarding anomalous mid-level ridging
across the central and east-central CONUS during the 6-10 day forecast period.
This is reflected in the manual 500-hPa height blend which depicts a +150 meter
positive height anomaly center to the south of Hudson Bay. The 0z GEFS depicts
stronger downstream shortwave troughing moving across the Northeast compared to
the 0z ECMWF and Canadian ensembles which indicate a more expansive ridge and
relatively weaker troughing along the East Coast. The mid-level pattern across
the North Pacific is predicted to be more transient. Troughing is initially
favored across Alaska, but ridging expanding from the west is forecast to
displace the largest negative height anomalies into the Arctic Ocean. Some
shortwave energy is also forecast to progress toward the West Coast of the
CONUS, with the Canadian ensemble being the most amplified of the guidance. As
a result of this evolution, the manual height blend indicates above-normal
heights across the Aleutians and closer to normal heights over southern
Mainland Alaska. Below-normal heights are more likely across the northern
Mainland and Southeast Alaska. The tropical eastern and central Pacific remains
active and may influence the sensible weather across Hawaii, with near-to
above-normal heights favored for the period as a whole.

As a result of broad mid-level ridging, probabilities for above-normal
temperatures are increased across most of the CONUS. The highest probabilities
(greater than 60 percent) are favored near the Gulf Coast and the Northern
Plains. Relatively weaker probabilities for above-normal temperatures are
forecast across the Southwest through the Midwest given a potential influx of
moisture and potentially saturated ground. Probabilities for above-normal
temperatures also decrease across the Pacific Northwest into northern
California due to troughing predicted to develop near the West Coast by the end
of the period. Near-normal temperatures are favored across parts of the
Northeast for the period as a whole tied to near- to below-normal temperatures
early in the period followed by a warming trend, with support from the GEFS and
ECMWF reforecast tools. Elevated chances for below-normal temperatures are
favored across much of western and central Mainland Alaska as well as the
Alaska Peninsula due to anomalous troughing at the start of the period.
Above-normal temperatures are more likely for parts of the Aleutians,
associated with increasing ridging and positive mid-level height anomalies.
Above-normal temperatures are predicted across Hawaii due to widespread
above-normal SSTs in the tropical eastern and central Pacific associated with
the current El Nino.

Probabilities for above-normal precipitation are increased across much of the
western CONUS, with chances exceeding 50 percent across portions of the
Southwest and Lower Four Corners. This is tied to the potential advection of
tropical moisture into the region, with the National Hurricane Center (NHC)
monitoring multiple systems off the coast of Mexico that may develop in the
next week. Farther east, underneath more influence from mid-level ridging and
with low precipitation totals in the uncalibrated ECMWF and GEFS ensembles,
near- to below-normal precipitation chances are increased across portions of
the Mississippi Valley, Midwest, and Great Lakes. Probabilities for
above-normal precipitation are increased closer to the Eastern Seaboard tied to
frontal activity, with the GEFS and GEFS-AI ensembles, as well as some
individual ECMWF members indicating a surface low across the Northeast around
the start of the period. Additionally, the same frontal boundary could lead to
additional surface low pressure development farther to the south bringing
enhanced precipitation to parts of the Southeast. Multiple areas of surface low
pressure favor increased chances for above-normal precipitation across Alaska,
with an initial system favoring enhanced precipitation across southeastern
Alaska followed by another surface low moving into western Alaska around the
middle of the period. An active eastern and central tropical Pacific favors
above normal precipitation across Hawaii.

The official 6-10 day 500-hPa height blend consists of 30% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 40% of Today`s 0z European Ensemble Mean
centered on Day 8, and 30% 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
model agreement regarding the mid-level pattern evolution across much of the
forecast domain, offset by uncertainty across the North Pacific and downstream
implications across the CONUS.

8-14 DAY OUTLOOK FOR SEP 24 - 30 2026

The 500-hPa pattern across North America is forecast to be stable, with many of
the features discussed in the 6-10 day period remaining in place during week-2.
Broad ridging is forecast across the central and east-central CONUS associated
with positive height anomalies across the Northern and Central Plains into the
Midwest, and a +90 meter positive height anomaly center south of Hudson Bay in
the manual blend. On either side of the ridge, troughs are more likely near the
West Coast of the CONUS and over the North Atlantic. The mid-level pattern
across Alaska is forecast to be more variable due to weakening of negative
height anomalies over the Arctic and some uncertainty related to the placement
of ridging. The 0z ECMWF and Canadian ensembles place a ridge axis near the far
western Aleutians and southern Bering Sea while the 0z GEFS indicates a ridge
centered over the Mainland later in the period. Some of this uncertainty may
also be tied to the progression of recurving tropical systems over the Western
Pacific. As a result, near-normal heights are indicated in the manual blend
across southern Mainland Alaska, with slightly below-normal heights across the
northern Mainland and Southeast Alaska. Above-normal heights are depicted over
the Aleutians. Near-normal heights are forecast across Hawaii.

With mid-level ridging the dominant feature across the CONUS during week-2,
probabilities for above-normal temperatures are increased over most areas. The
uncalibrated 0z GEFS is notably cooler across the East compared to other
guidance tied to a stronger shortwave trough moving through at the outset of
the period, and the analogs also tilt toward near-normal temperatures given
still some influence from a frontal boundary that may have a cooling effect.
Therefore, above-normal temperature probabilities were decreased across the
Eastern Seaboard compared to farther west. Chances for above-normal
temperatures are also lowered across the West, with near-normal temperatures
more likely across the Pacific Northwest and northwestern California.
Near-normal temperatures are favored for Alaska due to uncertainty regarding
the mid-level pattern evolution and some discrepancies among the tools. There
is better confidence across the Aleutians and Alaska Peninsula where
above-normal temperature probabilities are increased underneath an expanding
mid-level ridge. Odds for above-normal temperatures remain elevated across
Hawaii.

Probabilities for above-normal precipitation are enhanced across the western
half of the CONUS into the Upper Mississippi Valley, due to the combination of
cyclonic flow along the Pacific Coast and potential advection of moisture from
an active eastern tropical Pacific and entrainment into shortwaves propagating
along the downstream ridge axis. Below-normal precipitation chances are
increased farther to the east, across the Great Lakes southward through the
Middle Mississippi and Tennessee Valleys underneath ridging and supported by
statistical tools (analogs and teleconnections). Enhanced chances for
above-normal precipitation remain favored along the East Coast, with higher
odds (greater than 40 percent) across portions of the Southeast and coastal
Carolinas where the highest precipitation totals are depicted in the
uncalibrated GEFS and ECMWF ensembles. In Alaska, above normal precipitation is
favored for most of the Mainland, with higher probabilities to the west due to
potential surface low pressure. Near-normal precipitation is more likely across
the Aleutians, far eastern Mainland, and Southeast Alaska. Elevated
probabilities for above-normal precipitation persist across Hawaii.

The official 8-14 day 500-hPa height blend consists of: 30% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 40% of Today`s 0z European Ensemble Mean
centered on Day 11, and 30% 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
increasing uncertainty across the North Pacific, in addition to varying signals
regarding the temperature forecast across eastern and western parts of the
CONUS.

FORECASTER: Thomas Collow

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:
20190928 - 20180923 - 20180829 - 20050923 - 19900827


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:
20180923 - 20200912 - 20190929 - 20180830 - 19900827


6-10 DAY OUTLOOK TABLE
Outlook for Sep 22 - 26 2026

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



8-14 DAY OUTLOOK TABLE
Outlook for Sep 24 - 30 2026

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

                           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.

$$