674
FXUS06 KWBC 171902
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Mon August 17 2026

6-10 DAY OUTLOOK FOR AUG 23 - 27 2026

The ECENS, GEFS, and CMCE are in good agreement that an amplified 500-hPa ridge
becomes centered over the Great Plains during late August. 500-hPa heights are
forecast to remain near 596 dm through much of the 6-10 day period. The manual
500-hPa height blend depicts an expansive area with 5-day height departures of
more than 30 meters (significant for the summer) extending from the near the
West Coast to the Mississippi River. This strong mid-level ridge strongly
supports large above-normal temperature probabilities (> 60%) for the Rockies,
the Central to Southern Great Plains, and parts of the Southeast. The maximum
probabilities (> 80%) are forecast for the Southern Great Plains where the
ECENS and GEFS depict 5-day temperatures averaging more than 10 degF above
normal. For nearly all of the western Contiguous U.S. (CONUS), above-normal
temperatures are also favored although probabilities decrease farther away from
the ridge axis and closer to the West Coast. The multi-model ensemble mean
solutions have a mid-level trough of moderate amplitude across the eastern
Great Lakes and Northeast where near normal or a slight lean towards
below-normal temperatures is forecast.

Unlike the 6-10 day temperature outlook, forecast confidence is lower for
precipitation due to overall weak signals among the dynamical models along with
convection as the dominant mode of precipitation. The strong ridge aloft favors
below-normal precipitation across the Southern Great Plains, Lower Mississippi
Valley, and parts of the Southeast. During this 5-day period, the ensemble
means indicate less than 0.25 inch of precipitation for Oklahoma, Texas,
Arkansas, and most of Louisiana. A mid-level trough is expected to result in
one or two frontal passages across the Northeast and Mid-Atlantic, supporting a
slight lean towards above-normal precipitation for these areas. The building
ridge over the Great Plains and Mississippi Valley is expected to bring a
drying trend and only near normal precipitation is favored for much of the
central CONUS. The deterministic models and their ensemble members remain
consistent that a tropical cyclone (TC) forms over the East Pacific by next
weekend. At this time, the mid-level ridge over building over the Southwest is
likely to limit the amount of moisture moving into the Desert Southwest. Tools
continue to show modest signals for enhanced precipitation north of the Four
Corners into the Great Basin and Central and Northern Rockies.

There is good agreement for a closed 500-hPa low to the north of Alaska and
strong positive 500-hPa height anomalies over the Bering Sea and north-central
Pacific, bringing a trough into Mainland Alaska. This predicted longwave
pattern favors near to below-normal temperatures for western Mainland Alaska
with near-normal temperatures favored for the rest of the state. This mid-level
trough supports an increased chance of above-normal precipitation across much
of Alaska with lower probabilities across the southern portions of the state.

For Hawaii, above-normal precipitation is favored by the model guidance tied to
the potential influence from a TC that may form to the southeast of the
Hawaiian Islands later this week. The GEFS and ECENS support above-normal
temperature probabilities exceeding 70%.

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,  Good
agreement among the dynamical tools regarding heights and temperatures is
offset by low probabilities in the precipitation  outlook.

8-14 DAY OUTLOOK FOR AUG 25 - 31 2026

Similar to the 6-10 day period, the amplified 500-hPa ridge centered over the
Great Plains is forecast to be the main influence on the 8-14 day temperature
outlook. Although the ensemble spread increases later in week-2, the GEFS and
ECENS depict daily temperature anomalies of more than 5 degF above normal from
the Rockies to the Mississippi Valley through the end of week-2. The anomalous
and expansive 500-hPa ridge favors above-normal temperatures for a majority of
the lower 48 states. Above-normal temperature probabilities are most enhanced
(50-80% chance) across the Southeast, Lower to Middle Mississippi Valley, Great
Plains, Rockies, and Southwest. Near to below normal temperatures are forecast
for the Northeast where a more variable temperature pattern is anticipated due
to the mid-level trough. Based on the skill-weighted GEFS and ECENS
(consolidation tool), near normal temperatures are also most likely across
northern California and the western half of Oregon and Washington.

Due to the strong ridge aloft persisting through at least the early part of
week-2, below-normal precipitation continues to be favored across the Southern
Great Plains, the Lower Mississippi Valley, and along the Gulf Coast. Although
a robust monsoon circulation pattern appears unlikely given the predicted
placement of the 500-hPa ridge axis, dynamical models indicate elevated
above-normal precipitation probabilities extending from the Desert Southwest
northward to the northern Rockies and northern Great Plains. However, the
statistical analog guidance favors near to below normal precipitation across
much of the western CONUS. As a result, near-normal is generally favored across
the region with a slight tilt towards above normal displaced northwards over
the northern and central Rockies and High Plains. A mid-level trough slightly
favors above-normal precipitation across the Northeast. In the Great Lakes,
below normal precipitation is slightly favored behind the main trough axis.
Elsewhere, near normal precipitation is favored due to either weak signals
among the tools (Plains, Mississippi Valley) or in the typically drier areas of
the western CONUS during late August.

A broad mid-level trough favors near to below-normal temperatures for a
majority of western Alaska. However, based on the consolidation tool, elevated
above-normal temperature probabilities are forecast across southeastern Alaska.
The mid-level trough increases the chance of above-normal precipitation across
northwestern Alaska. The preferred uncalibrated model output supports near
normal precipitation for the remainder of the state.

Based on the elevated chance of additional TCs to track across the Central
Pacific through late August along with a strong wet signal among the tools,
above-normal precipitation is favored for Hawaii. The GEFS and ECENS support
large above-normal temperature probabilities.

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: Average, 3 out of 5,  Good
agreement among the dynamical tools regarding heights and temperatures is
offset by low probabilities in the precipitation  outlook.

FORECASTER: Ryan Bolt

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
August 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:
20100801 - 20050816 - 20230824 - 20090806 - 20240806


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:
20050815 - 20100731 - 20090806 - 20240806 - 20170808


6-10 DAY OUTLOOK TABLE
Outlook for Aug 23 - 27 2026

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



8-14 DAY OUTLOOK TABLE
Outlook for Aug 25 - 31 2026

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

$$