057
FXUS06 KWBC 181902
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Fri September 18 2026

6-10 DAY OUTLOOK FOR SEP 24 - 28 2026

Dynamical models are in good agreement regarding anomalous mid-level ridging
across the 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 and above-normal heights extending
throughout much of the CONUS. Troughing and potential cut-off mid-level low
pressure remain forecast near the East Coast, with slightly below-normal
heights indicated in the manual blend. A more transient pattern is favored
across the North Pacific with a series of troughs shifting from the Bering Sea
to near the west coast of North America, with initial ridging near southern
Alaska retreating and a subsequent lowering of heights. As a result of this
evolution, the manual height blend indicates near-normal heights over much of
Alaska, tilting toward slightly below-normal across Southeast Alaska and the
far western Mainland. A -60 meter negative height anomaly center is indicated
off the west coast of North America. 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 central and western CONUS. The
highest probabilities (greater than 60 percent) are favored over southern Texas
and the Northern Plains into parts of the northern and central Rockies.
Relatively weaker probabilities for above-normal temperatures are forecast
across New Mexico given potentially saturated ground tied to enhanced
precipitation. Probabilities for above-normal temperatures also decrease closer
to the West Coast due to troughing moving into the northeastern Pacific, with
near-normal temperatures more likely across western portions of Washington,
Oregon, and extreme northwestern California. An unsettled pattern is likely
across the Northeast and Mid-Atlantic tied to cut-off troughing underneath the
aforementioned ridging as well as surface low pressure off the coast resulting
in increased cloud cover and precipitation, thus lowering temperatures. This
favors elevated probabilities for near- to below-normal temperatures over much
of the region, with support from the uncalibrated 0z ECMWF and GEFS ensembles,
and the ECMWF reforecast tool. A variable mid-level height pattern results in
near-normal temperatures being favored across much of northern and eastern
Mainland Alaska and Southeast Alaska. Above-normal temperature chances are
increased across much of southwestern Alaska, and the Aleutians tied to initial
ridging. Above-normal temperatures are likely 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 60 percent across portions of the
Southwest. This is tied to the potential advection of tropical moisture into
the region, with the National Hurricane Center (NHC) monitoring Invest 99E in
addition to other systems across the basin that may develop in the next week.
Invest 99E has an 80 percent chance to develop into a tropical cyclone in the
next week per NHC, and a potential northward track may bring increased tropical
moisture and enhanced precipitation totals across much of the Southwest.
Farther east, underneath more influence from mid-level ridging and with low
precipitation totals in the uncalibrated ECMWF and GEFS ensembles, below-normal
precipitation chances are increased across portions of the Mississippi and
Tennessee Valleys, Midwest, and Great Lakes. The largest probabilities (greater
than 50 percent) are colocated with predicted surface high pressure over the
Great Lakes. A tight gradient between below- and above-normal precipitation is
likely across the East Coast and there is considerable uncertainty into how
much precipitation reaches the coast. The 0z ECMWF ensemble has more members
drifting surface low pressure back toward the coastal Northeast or New England
which could enhance precipitation. However, the 0z GEFS generally favors a more
offshore track which would result in a drier outcome than the ECMWF, and these
differences result in only a slight tilt to enhanced above-normal precipitation
odds along the East Coast. Surface low pressure tracking from the Bering Sea to
the Gulf of Alaska favors increased chances for above-normal precipitation
across much of Mainland and Southeast Alaska. 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 decreasing predictability of transient features,
particularly across the North Pacific.

8-14 DAY OUTLOOK FOR SEP 26 - OCT 02, 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 central Canada associated with positive height
anomalies across the Northern Plains into the Upper Midwest, and a +90 meter
positive height anomaly center over southern portions of the Hudson Bay in the
manual blend. As discussed in the 6-10 day outlook, models are in good
agreement regarding cut-off mid-level low pressure near the East Coast early in
the period. While this feature weakens with time, near-normal heights remain
forecast for the period as a whole along the Eastern Seaboard into the
Southeast and Lower Mississippi Valley. Increased troughing is forecast across
the northeastern Pacific into Alaska, with the 0z ECMWF, GEFS, and Canadian
ensembles all showing an amplified trough off the West Coast of the CONUS
extending into the western Alaska during the second half of the period. This
results in near-normal heights across the Pacific Northwest and northern
California, with below-normal heights becoming more likely over Alaska.
Near-normal heights are forecast across Hawaii.

Above-normal temperature probabilities remain elevated across much of the CONUS
tied to the continued influence from ridging. The uncalibrated ECMWF and GEFS
ensembles continue to support below-normal temperatures across the Northeast
and Mid-Atlantic. However, the weakening of the cut-off mid-level low and a
relatively warmer signal in the reforecast tools justifies favoring near-normal
temperatures for the period as whole. Near-normal temperatures are also more
likely across the Pacific Northwest, parts of the northern Great Basin, and
much of northern California tied to troughing off the West Coast. Across
Alaska, enhanced southerly flow supports a slight tilt toward above-normal
temperatures across southern Mainland Alaska and the Aleutians, with
near-normal temperatures favored elsewhere across the state. 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 off the Pacific Coast and potential advection of moisture from an
active eastern tropical Pacific, although this may begin to wane later in
week-2. Below-normal precipitation chances are increased farther to the east,
across the Great Lakes, Ohio Valley, and Interior Northeast. Enhanced chances
for above-normal precipitation remain favored along the East Coast, with a
stalled frontal boundary and additional offshore surface low development
possible. The positioning of this frontal boundary will influence precipitation
chances for much of the Eastern Seaboard. While above-normal precipitation is
more likely across Florida into the Southeast, the 0z GEFS progresses surface
high pressure farther east compared to the 0z ECMWF ensemble which would result
in a drier outcome across northern areas. Above-normal precipitation is favored
for most of southern Mainland and Southeast Alaska tied to potential surface
low pressure. Near-normal precipitation is more likely across the northern
Mainland. 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
deamplifying signals across the CONUS and a transient pattern upstream over the
North Pacific.

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
October 15.


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:
20180829 - 20230903 - 20050923 - 20180923 - 20200912


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 - 20050923 - 20180830 - 20200912 - 20190929


6-10 DAY OUTLOOK TABLE
Outlook for Sep 24 - 28 2026

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  N    A     OREGON      A    A     NRN CALIF   A    N
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    A
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    A
MINNESOTA   A    A     IOWA        A    B     MISSOURI    A    B
ARKANSAS    A    B     LOUISIANA   A    B     WISCONSIN   A    B
ILLINOIS    A    B     MISSISSIPPI A    B     MICHIGAN    A    B
INDIANA     N    B     OHIO        N    B     KENTUCKY    N    B
TENNESSEE   N    B     ALABAMA     A    B     NEW YORK    N    B
VERMONT     N    N     NEW HAMP    N    A     MAINE       N    N
MASS        B    A     CONN        B    A     RHODE IS    B    A
PENN        B    N     NEW JERSEY  B    A     W VIRGINIA  B    N
MARYLAND    B    A     DELAWARE    B    A     VIRGINIA    B    A
N CAROLINA  N    A     S CAROLINA  N    N     GEORGIA     N    N
FL PNHDL    A    N     FL PENIN    A    A     AK N SLOPE  N    A
AK ALEUTIAN A    A     AK WESTERN  A    A     AK INT BSN  N    A
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    N    A



8-14 DAY OUTLOOK TABLE
Outlook for Sep 26 - Oct 02, 2026

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  N    A     OREGON      N    A     NRN CALIF   N    N
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    A
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    A
MINNESOTA   A    A     IOWA        A    A     MISSOURI    A    A
ARKANSAS    A    N     LOUISIANA   A    A     WISCONSIN   A    N
ILLINOIS    A    N     MISSISSIPPI A    N     MICHIGAN    A    B
INDIANA     A    B     OHIO        A    B     KENTUCKY    A    B
TENNESSEE   A    B     ALABAMA     A    N     NEW YORK    A    B
VERMONT     A    B     NEW HAMP    N    N     MAINE       A    B
MASS        N    N     CONN        N    N     RHODE IS    N    N
PENN        N    N     NEW JERSEY  N    N     W VIRGINIA  N    B
MARYLAND    N    N     DELAWARE    N    N     VIRGINIA    N    N
N CAROLINA  N    N     S CAROLINA  N    A     GEORGIA     A    A
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  N    N
AK ALEUTIAN A    N     AK WESTERN  N    N     AK INT BSN  N    N
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    N    A

                           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.

$$