864
FXUS06 KWBC 041905
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 04 2026

6-10 DAY OUTLOOK FOR SEP 10 - 14 2026

Today`s numerical models predict a complex 500-hPa flow pattern, especially
across the western Contiguous United States (CONUS). The tropical eastern and
central North Pacific remains active, with three hurricanes currently scattered
across the region (category-4 Lowell, category-1 Karina, category-2 Marie) and
there are elevated chances for at least one additional system to form during
the 6-10 or 8-14 day period. Any system that forms has the potential to affect
Hawaii. Meanwhile, a mean 500-hPa trough is forecast near the West Coast. This
has the potential of advecting tropical moisture from the active eastern North
Pacific into the western CONUS. Downstream, a mid-level ridge is expected to
prevail across a large part of the CONUS, with maximum 500-hPa height anomalies
centered over the central or east-central CONUS. Downstream, the ensemble mean
consensus shows a persistent 500-hPa trough over or near the Canadian
Maritimes, with an axis stretching southward along or near the Eastern
Seaboard. Models remain in good agreement on this generalized mean pattern, and
are in somewhat better agreement regarding the placement of the primary
mid-level features affecting the Lower-48, but uncertainty remains due to model
forecast disparities regarding the strength of these features and how the
situation evolves with time. Despite these differences, model consensus has
trended a little stronger with the mid-level troughs near both CONUS
coastlines. The manual blend shows mean 500-hPa height anomalies near -6 dm
centered just off the western CONUS coast, and across Atlantic Canada. Between
these features, model differences handling the interior CONUS ridge have
decreased, with most placing the mean axis over the central or interior eastern
CONUS, near or slightly west of the GEFS solution yesterday. The manual blend
depicts 500-hPa anomalies exceeding +6 dm over the Middle Mississippi Valley.

Farther north, a sharp 500-hPa height gradient is forecast across Alaska,
resulting in an active pattern. Anomalous ridging is expected across the
Aleutians and adjacent North Pacific, where mean 500-hPa height anomalies reach
+12 dm in the manual blend. At the same time, a mean anomalous trough is
expected to the north and west of the state, with 500-hPa height anomalies near
-3 dm across the northern tier of Mainland Alaska. An active pattern is also
expected across Hawaii due to elevated tropical activity in the eastern and
central North Pacific, south of a mid-level ridge. Please refer to the National
Hurricane Center for the latest information on tropical conditions.

The mid-level ridging expected across much of the CONUS favors above normal
temperatures from the Rockies eastward through central and southern sections of
the Atlantic Coast. Chances for above-normal temperatures exceed 80 percent in
parts of the south-central Great Plains and adjacent Mississippi Valley.
Meanwhile, near or below-normal temperatures are favored across the western and
northeastern sections of the CONUS under the influence of mid-level troughing.
There are slightly elevated chances for warmer than normal conditions across
most of Alaska outside the southwestern Mainland, consistent with the consensus
of bias-corrected and calibrated ensemble model output. Chances for unusual
warmth exceed 40 percent in much of the northwestern and southeastern portions
of the state. Farther south, a large reservoir of abnormally high sea surface
temperatures (SSTs) surrounds Hawaii. Adjacent waters are 0.5 to locally 1.5
deg C above normal, with the greatest anomalies most common near the Big
Island. Chances for warmth increase from northwest to southeast across the
island chain, exceeding 70 percent on most of the Big Island.

Above-normal precipitation is favored across most of the West, tied to
persistent cyclonic mid-latitude flow downstream from mid-level troughing. This
pattern often favors the advection of tropical moisture into the region which
could be exacerbated by any tropical development in the active eastern tropical
Pacific. Confidence for above-normal precipitation is highest (above 60 percent
chance) along the western tier of the CONUS from the western Rockies to the
northern half of the Pacific Coast. Elevated chances of above-normal
precipitation extend eastward through the Rockies and across the far northern
tier of the CONUS, along the periphery of the anticipated mid-level ridge.
There is a lot of uncertainty farther east from the Great Plains to the
Atlantic Coast outside the northern tier. Raw and reforecast model output
marginally favors above-normal precipitation, although the consensus signal is
weaker than yesterday. Meanwhile, analogs to the manual blend and individual
ensemble means, in addition to teleconnections keying on the primary mid-level
features, largely favor subnormal precipitation over some portion of the
central and eastern CONUS. Given this discrepancy, the official forecast favors
a compromise, with near normal precipitation anticipated over a broad area
covering most of the central and eastern CONUS. Meanwhile, the enhanced
mid-level height gradient across Alaska supports an active pattern there,
leading to elevated probabilities of above-normal precipitation for most of the
state. Above-normal precipitation is also favored across Hawaii, consistent
with most guidance. Amounts could be enhanced by any tropical development in
the central and eastern Pacific, which is expected to remain active. Odds for
surplus precipitation exceed 50 percent statewide, and top 60 percent across
the Big Island.

The official 6-10 day 500-hPa height blend consists of 35% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 20% of Today`s 6z GFS Ensemble Mean centered
on Day 8, 15% of Today`s 0z European Ensemble Mean centered on Day 8, 15% of
Today`s operational 0z ECMWF centered on Day 8, and 15% of Today`s 0z Canadian
Ensemble Mean centered on Day 8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Average, 3 out of 5, with good
model agreement on the mid-level pattern offset by the predicted complex
pattern over the western CONUS, the inherent uncertainty of tropical
conditions, and the sharp differences between model-derived precipitation
forecasts compared to analog and teleconnection signals.

8-14 DAY OUTLOOK FOR SEP 12 - 18 2026

The general pattern of mid-level features is expected to continue during the
week-2 period. Some deamplification is forecast by the ensemble means, but at
least part of this signal is probably driven by the inherent uncertainty of
later forecast time frames. Models are most aggressive in deamplifying the
500-hPa ridge in the North Pacific, where the greatest mean height anomalies
drop from +12 to +15 dm during the 6-10 day period, to between +3 and +6 dm for
week-2. With continued troughing to the north and west of the state, the active
pattern over Alaska is expected to continue, but will likely diminish with
time. The active eastern and central tropical Pacific and some degree of
continued mid-level troughing near the West Coast favor a continuing influx of
tropical moisture in the western CONUS, although model consensus is less robust
with this signal than during the 6-10 day period. Expansive ridging is forecast
to persist across much of the interior CONUS, with the mean axis moving very
little relative to the 6-10 day period. Models are in better agreement on this
week-2 pattern than they have been the past few days. Mid-level troughing is
expected to continue over Atlantic Canada, favoring slightly below-normal
heights across northern parts of the Eastern Seaboard. There remains a good
deal of uncertainty regarding how far south this trough will influence
conditions along the East Coast. An active pattern is also anticipated across
Hawaii, but the sensible weather across the state will depend on the evolution
of individual tropical systems.

Above-normal temperatures are likely to persist across a large portion of the
CONUS during week-2 under the persistent mid-level ridge. Confidence remains
highest (over 70 percent chance) from the southeastern Great Plains eastward
through the central Gulf Coast states. The mid-level troughing near Atlantic
Canada reduced temperature forecast confidence along the Atlantic Seaboard, but
warmer than normal conditions are at least marginally favored outside eastern
New England, which will be closest to the trough. Mid-level troughing near the
western CONUS is expected to gradually weaken with time, but enhanced chances
for subnormal temperatures remain over much of the central and northern Pacific
Coast, much of the Great Basin, and part of the Northern Intermountain West.
Warmer than normal weather remains favored across most of Alaska despite the
deamplifying North Pacific mid-level ridge, consistent with bias-corrected and
reforecast ensemble output. Enhanced chances for above-normal temperatures also
continue for Hawaii, consistent with continued above-normal SSTs across the
eastern and central tropical Pacific. Chances are greatest where SST anomalies
are generally the highest, near the Big Island.

The combination of mid-level troughing near the West Coast and increased
activity in the eastern tropical Pacific supports a continuation of
above-normal precipitation across much of the West, with probabilities of
above-normal precipitation exceeding 40 percent from the Pacific Coast into the
High Plains, and topping 50 percent in the interior Pacific Northwest.
Downstream, wetter than normal weather is marginally favored over the northern
Plains and adjacent Great Lakes, but guidance has trended drier across most of
the eastern half of the CONUS. There remains considerable uncertainty across
most of these areas. Dynamical models depict wetter solutions here than the
analogs and teleconnections, but they have been slowly trending toward showing
less precipitation over the eastern half of the CONUS. As a result, the
official forecast now nominally favors subnormal precipitation across most
areas from the Middle Mississippi and Ohio Valleys through the Mid-Atlantic
region, the lower Great Lakes, and the Northeast. Above-normal precipitation is
favored for most of Alaska as the active pattern is expected to continue,
especially early in the period. An active pattern is also expected to remain in
place across Hawaii, but precipitation totals could vary significantly
depending on the evolution of conditions across the active tropical Pacific.
The likelihood of above-normal week-2 precipitation totals exceeds 50 percent
throughout the island chain, and tops 60 percent on the Big Island and the
eastern half of Maui.

The official 8-14 day 500-hPa height blend consists of: 40% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 20% of Today`s 6z GFS Ensemble Mean centered
on Day 11, 25% of Today`s 0z European Ensemble Mean centered on Day 11, and 15%
of Today`s 0z Canadian Ensemble Mean centered on Day 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Average, 3 out of 5, with better
model agreement on the longwave pattern offset by uncertainty in the tropics,
the predicted complex mid-level low pattern in the western CONUS, and
differences in precipitation forecasts between the dynamical guidance and the
drier analogs and teleconnections.

FORECASTER: Rich Tinker

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:
20190917 - 20240822 - 20240912 - 20050904 - 20040918


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:
20050905 - 20240822 - 20190916 - 20240912 - 20050831


6-10 DAY OUTLOOK TABLE
Outlook for Sep 10 - 14 2026

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



8-14 DAY OUTLOOK TABLE
Outlook for Sep 12 - 18 2026

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  B    A     OREGON      B    A     NRN CALIF   B    A
SRN CALIF   N    A     IDAHO       N    A     NEVADA      B    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    N     OKLAHOMA    A    N
N TEXAS     A    N     S TEXAS     A    N     W TEXAS     A    N
MINNESOTA   A    A     IOWA        A    N     MISSOURI    A    N
ARKANSAS    A    N     LOUISIANA   A    N     WISCONSIN   A    N
ILLINOIS    A    B     MISSISSIPPI A    N     MICHIGAN    A    N
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    B     MAINE       N    N
MASS        A    B     CONN        A    B     RHODE IS    A    B
PENN        A    B     NEW JERSEY  A    B     W VIRGINIA  A    B
MARYLAND    A    B     DELAWARE    A    B     VIRGINIA    A    B
N CAROLINA  A    N     S CAROLINA  A    N     GEORGIA     A    N
FL PNHDL    A    N     FL PENIN    A    N     AK N SLOPE  A    A
AK ALEUTIAN A    N     AK WESTERN  A    A     AK INT BSN  A    A
AK S INT    A    A     AK SO COAST A    N     AK PNHDL    A    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.

$$