852
FXUS06 KWBC 211919
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Fri August 21 2026

6-10 DAY OUTLOOK FOR AUG 27 - 31 2026

The 0Z ECENS, GEFS, and CMCE ensemble model forecasts continue to predict a
relatively amplified 500-hPa height pattern for summer over the North American
domain during the 6-10 day forecast period. Models predict an amplified ridge
and positive 500-hPa height anomalies across the Aleutian Islands into
southwestern Mainland Alaska during the period. A trough and negative 500-hPa
height anomalies are predicted farther north over the Arctic Ocean near
northwestern Mainland Alaska. The manual height blend depicts slightly stronger
mean circulation features across the Alaska domain today relative to yesterday.
The manual height blend is based on the 0Z ECENS, GEFS, and CMCE model 500-hPa
height forecasts, weighting the ECENS greater due to recent model skill. Near
and over the Lower 48 states, the manual blend predicts a mid-level trough to
approach the Pacific Northwest coast, accompanied by near to slightly below
normal heights. This represents an eastward shift relative to yesterday. As a
result, the downstream mid-level ridge over the interior West is displaced
eastward over the west-central and central Contiguous U.S. (CONUS), with a
large 594-dm height contour forecast over the southwestern and southcentral
CONUS. This is in opposition to yesterdays forecast of a slight westward
retrogression of these features. Over the northeastern CONUS, a weak mid-level
trough is anticipated, accompanied by near normal heights. The Southeast
remains a  transition zone between the weak troughing to the north and
subtropical ridging to the south. Near to slightly above normal 500-hPa heights
are forecast over Hawaii.

Above normal temperatures are favored across the Aleutian Islands under
predicted positive 500-hPa height anomalies. Below normal temperatures are
favored for most of Mainland Alaska and parts of the Alaska Peninsula, with
enhanced cyclonic flow and cloud cover. Over the Lower 48 states, near to below
normal temperatures are favored over the Pacific Northwest including northern
California, and the Northern Basin due to an approaching trough. Near normal
temperature chances are elevated over much of the Upper Great Lakes region due
to run-to-run uncertainty regarding the alternating progression and
retrogression of the west-central CONUS ridge. For the remaining vast majority
of the CONUS elevated chances for above normal temperatures are indicated,
based on a majority of objective tools and the forecast presence of broad,
mid-level ridging and positive height anomalies. The greatest probabilities for
warmer-than-normal temperatures include 70-80 percent over central and southern
Florida, and 80-90 percent over the Lower Four Corners region. Supported by
most temperature tools, above normal temperatures are likely for Hawaii.

Above normal precipitation is favored for most of the Aleutians, Mainland
Alaska, and Southeast Alaska, associated with onshore flow along the western,
northern, and eastern flanks of the Aleutian ridge. This is also consistent
with the consolidation of calibrated model precipitation forecasts. Over the
CONUS, above normal precipitation is favored over the Pacific Northwest, most
of the Northern and Central Plains, most of the Mississippi Valley and all
points east of there to the Atlantic coast, excluding central and southern
parts of the Florida Peninsula where near normal precipitation is highlighted.
Chances for above normal precipitation reach 50-60 percent near the Northeast
coast. One low pressure area is expected to slowly transit the East Coast
states, while another low spreads enhanced precipitation across parts of the
north-central CONUS. A slight tilt towards below normal precipitation is
favored to extend southeastward from eastern Oregon and southern Idaho to New
Mexico and much of Texas, consistent with the consolidation. Above normal
precipitation is favored across Hawaii, consistent with most dynamical model
forecasts.

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: Above Average, 4 out of 5, due to
good agreement between model forecasts of the mean large-scale mid-level height
and temperature patterns, offset by weaker signals in precipitation tools.

8-14 DAY OUTLOOK FOR AUG 29 - SEP 04, 2026

The overall predicted 500-hPa height pattern is relatively persistent into the
8-14 day period in ensemble model forecasts, with small changes relative to the
6-10 day period forecast. The exception is over the Aleutians on the manual
height blend where the predicted amplitude of a mid-level ridge is half of that
forecast in the 6-10 day period (i.e., 90 meters above normal compared to 180
meters above normal). Very weak troughing continues over northwestern Alaska,
while weak troughing persists near the Pacific Northwest coast. A broad
mid-level ridge is predicted to continue mostly from the interior West eastward
across the Rockies, Plains, and Mississippi Valley. The large 594-dm height
contour depicted on the 6-10 day blend has been reduced significantly in size
during week-2. In the northeastern CONUS, the weak trough axis has advanced
slightly from the Lower Great Lakes region to near the Atlantic coast, with
little discernible change in the height pattern across the Southeast. Near to
slightly above normal 500-hPa heights are forecast over Hawaii.

The week-2 temperature outlook for the CONUS and Alaska is very similar to the
earlier 6-10 day temperature outlook, with only modest adjustments made. The
near normal temperatures favored over the Upper Great Lakes region in the 6-10
day period were shifted eastward into the Lower Great Lakes region during
week-2, based on expected advection of the Eastern trough. The greatest chances
for above normal temperatures is 70-80 percent from eastern Arizona to eastern
Texas, consistent with the consolidation forecast. Dynamical model forecasts
agree on likely above normal temperatures for Hawaii.

Above normal precipitation is favored for the western and central Aleutians and
most of Mainland and Southeast Alaska, for reasons described in the earlier
6-10 day precipitation section. Above normal precipitation is favored for the
Pacific Northwest and adjacent parts of northwestern California, along with the
Dakotas, and much of Minnesota, due to a mid-level trough along the Northwest
coast and the progression of shortwave activity inland supported by the
consolidation tool. Other areas of favored above normal precipitation include
the Ohio Valley, eastern Great Lakes, Northeast, and Upper Mid-Atlantic, which
is consistent with the passage of a mid-level trough through that region; and
also a small sliver of the Southwest, in relation to a weakened monsoon. Slight
tilts towards below normal precipitation are indicated over the Central Great
Basin, and the south-central CONUS, with good support from the consolidation.
Above normal precipitation is likely for Hawaii in the 8-14 day period,
consistent with most dynamical model forecast tools.

The official 8-14 day 500-hPa height blend consists of: 25% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 50% 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: Average, 3 out of 5, due to
reasonable agreement among dynamical models on the height and temperature
forecasts, offset by weak precipitation signals.

FORECASTER: Anthony A

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:
20100804 - 20100817 - 20160824 - 19970814 - 20190904


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:
20100801 - 20190903 - 20160825 - 20230826 - 20230831


6-10 DAY OUTLOOK TABLE
Outlook for Aug 27 - 31 2026

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  B    A     OREGON      N    N     NRN CALIF   N    N
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    B
W MONTANA   A    N     E MONTANA   A    A     WYOMING     A    N
UTAH        A    B     ARIZONA     A    B     COLORADO    A    N
NEW MEXICO  A    B     N DAKOTA    A    A     S DAKOTA    A    A
NEBRASKA    A    A     KANSAS      A    N     OKLAHOMA    A    N
N TEXAS     A    N     S TEXAS     A    B     W TEXAS     A    B
MINNESOTA   A    A     IOWA        A    A     MISSOURI    A    A
ARKANSAS    A    N     LOUISIANA   A    N     WISCONSIN   A    A
ILLINOIS    A    A     MISSISSIPPI A    N     MICHIGAN    N    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    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    A
N CAROLINA  A    A     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    A    A     FL PENIN    A    N     AK N SLOPE  B    A
AK ALEUTIAN N    N     AK WESTERN  B    A     AK INT BSN  B    A
AK S INT    B    A     AK SO COAST N    N     AK PNHDL    N    A



8-14 DAY OUTLOOK TABLE
Outlook for Aug 29 - Sep 04, 2026

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

$$