599
FXUS06 KWBC 201902
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Sun September 20 2026

6-10 DAY OUTLOOK FOR SEP 26 - 30 2026

The 0z GEFS, ECMWF, and Canadian ensembles are in good agreement regarding the
evolution of the 500-hPa height pattern across North America during the 6-10
day period. The manual height blend is based on 0Z ECMWF, GEFS, and Canadian
model 500-hPa height forecasts, weighting the ECMWF ensemble mean greater due
to recent model skill. The manual blend indicates anomalous mid-level ridging
and above-normal heights across the north-central and northeastern CONUS during
the 6-10 day forecast period, with a positive 500-hPa anomaly center of 120
meter located over the southern parts of the Hudson Bay. Troughing remains
forecast near the East Coast, with slightly below-normal heights indicated in
the manual blend. The manual height blend indicates a trough and below-normal
heights over western Mainland Alaska and the Aleutians extending southeastward
to near 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.

Probabilities for near- to above-normal temperatures are increased across most
of the CONUS. The highest probabilities (greater than 60 percent) are over
southern Texas, consistent with most of the dynamical temperature forecast
tools. Below-normal temperatures are forecast over parts of the Pacific
Northwest due to troughing moving into the northeastern Pacific. Below-normal
temperatures are also likely over parts of the Middle Atlantic, with support
from the operational autoblend temperature forecast tool. A variable mid-level
height pattern results in near- to above-normal temperatures being favored
across the Aleutians, Mainland Alaska and Southeast Alaska. 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 and central CONUS, with chances exceeding 50 percent across portions of
the southwestern CONUS. Farther east, underneath more influence of mid-level
ridging and supported by low precipitation totals in the uncalibrated ECMWF and
GEFS ensembles, below-normal precipitation chances are increased across
portions of the Tennessee Valley, Ohio Valley, Midwest, and Great Lakes.
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, consistent with the consolidation
precipitation forecast tool.

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 28 - OCT 04, 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 +60 meter
positive height anomaly center over the Hudson Bay in the manual blend. 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, consistent with operational
autoblend and ERF consolidation temperature forecast tools. Near-normal
temperatures are more likely across much of the Pacific Northwest and portions
of northern California, associated with troughing off the West Coast.
Below-normal temperatures are favored across parts of northwestern Mainland
Alaska, while above-normal temperatures are forecast over eastern Mannland
Alaska and Southeast Alaska, supported by most of the dynamical temperature
forecast tools. Odds for above-normal temperatures remain elevated across
Hawaii given continued strong support from the reforecast temperature
consolidation tool.

Probabilities for above-normal precipitation are enhanced across most of the
CONUS (except for portions of the Northern Rockies, where near-normal
precipitation is favored), due to the combination of cyclonic flow off the
Pacific Coast, potential advection of moisture from an active eastern tropical
Pacific, and a trough predicted over the southeastern CONUS, supported by most
of the dynamical precipitation forecast tools. Above-normal precipitation is
favored for most of southeastern Mainland and Southeast Alaska tied to
potential surface low pressure. Elevated probabilities for above-normal
precipitation persist across Hawaii, consistent with consolidated
skill-weighted precipitation amounts from the ECMWF and GEFS Ensembles.

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: Luke H

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
2026-09-20.


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:
20171004 - 20251004 - 20230903 - 20050920 - 20240904


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:
20171003 - 20050923 - 20230903 - 20200913 - 20050914


6-10 DAY OUTLOOK TABLE
Outlook for Sep 26 - 30 2026

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



8-14 DAY OUTLOOK TABLE
Outlook for Sep 28 - Oct 04, 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    N     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    A     LOUISIANA   A    A     WISCONSIN   A    A
ILLINOIS    A    A     MISSISSIPPI A    A     MICHIGAN    A    A
INDIANA     A    A     OHIO        A    A     KENTUCKY    A    A
TENNESSEE   A    A     ALABAMA     A    A     NEW YORK    A    A
VERMONT     A    A     NEW HAMP    A    A     MAINE       A    N
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    A
N CAROLINA  A    A     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  N    N
AK ALEUTIAN N    N     AK WESTERN  N    N     AK INT BSN  A    N
AK S INT    N    N     AK SO COAST A    N     AK PNHDL    A    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.

$$