113
FXUS06 KWBC 081902
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 08 2025

6-10 DAY OUTLOOK FOR AUG 14 - 18 2025

The 0z GEFS, ECENS, and CMCE ensembles depict a positive North Atlantic
Oscillation (+NAO) at the beginning of the 6-10 day period, with above-normal
500-hPa heights across the Northeast, extending over the North Atlantic, and
below-normal heights over Greenland. This pattern is forecast to weaken toward
the end of the period, with broad ridging expanding over much of the central
and eastern CONUS. Ridging initially favored across the northeast Pacific is
forecast to retrograde toward the Bering Sea, with lowering mid-level heights
and troughing developing over western North America. The ECENS and GEFS are
considerably more amplified with this troughing compared to yesterday, showing
a greater expanse of negative 500-hPa height anomalies over the western CONUS.
Today`s 6-10 day manual height blend depicts positive height anomalies across
much of the north-central and northeastern CONUS, extending southward into the
Tennessee Valley. Near-normal heights are favored along the Southern Tier of
the CONUS, with near-to below-normal heights now indicated across the
Northwest. Near- to below-normal heights are indicated over most of Mainland
and Southeast Alaska, with increasing positive height anomalies over the
Aleutians.

Probabilities of above-normal temperatures are elevated across much of the
CONUS during the 6-10 day period, with the highest chances (greater than 70
percent) encompassing a broad area from the Great Plains to the Northeast (tied
to a broadening of the mid-level ridge). The trend toward more troughing in the
West has resulted in the dynamical models coming into better agreement with the
analog and teleconnection statistical tools, supporting enhanced probabilities
of below-normal temperatures across the CONUS west of the Rockies. Chances of
below-normal temperatures are increased for most of Alaska, supported by nearly
all of the forecast tools. Near- to slightly above-normal temperatures are
favored over portions of the southern coast, given a stronger signal for warmer
temperatures in the GEFS and ECENS reforecast tools. Above-normal temperatures
are most likely for Hawaii associated with above-normal sea surface
temperatures, especially for western portions of the island chain.

A tranquil precipitation pattern is forecast across much of the CONUS during
the 6-10 day period, with slightly enhanced chances of near- to above-normal
precipitation over much of the eastern and Northern Tier of the CONUS. More
amplified troughing in the West supports higher chances (greater than 40
percent) of above-normal precipitation over the Northwest, with the added
potential for shortwaves to track southeastward out of Canada overtop the
expanding ridge, resulting in an extension of these higher probabilities into
parts of the Upper Midwest. Elevated probabilities of below-normal
precipitation are favored across the Great Basin and Central and Southern
Plains, underneath weak synoptic forcing and supported by the uncalibrated GEFS
and ECENS. The Southwest Monsoon may become active, supporting slightly
above-normal precipitation chances over parts of the Southwest and Four
Corners. An active pattern is anticipated across Alaska, although ridging
shifting toward the Bering Sea and the Aleutians favors a drying trend across
southwestern parts of the state. Probabilities of above-normal precipitation
remain elevated across most of the Mainland and Southeast Alaska, with near- to
below-normal precipitation chances increased over portions of southwestern
Mainland Alaska and the eastern Aleutians. Near- to above-normal precipitation
is favored for Hawaii.

The official 6-10 day 500-hPa height blend consists of 30% of Today`s 6z 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 among todays ensemble means, but offset by weak precipitation
signals across most of the CONUS.

8-14 DAY OUTLOOK FOR AUG 16 - 22 2025

Dynamical models continue to evolve toward a low amplitude, broad mid-level
ridge over much of the CONUS during week-2, and weak troughing along the west
coast of North America into Alaska. This troughing is forecast to weaken later
in the period as ridging becomes more dominant across the entire CONUS, with
the height maximum becoming situated over the Four Corners. The week-2 500-hPa
manual height blend depicts +60 meter height anomalies over portions of the
Upper Midwest, with +30 meter anomalies expanding further westward over parts
of the Rockies and Great Basin compared to yesterday. Closer to normal heights
are forecast across the West Coast and over the Southern Tier of the CONUS.
Near-normal heights are indicated across most of Alaska, with positive height
anomalies over the southwestern Mainland and Aleutians.

Enhanced chances of above-normal temperatures continue to be favored across
most of the CONUS during week-2 underneath dominant low amplitude ridging and
supported by the GEFS and ECENS reforecast tools. As discussed in the 6-10 day
outlook, there is a notable cooling trend across the West. However,
temperatures are predicted to moderate later in the week-2 period as troughing
weakens and mid-level heights increase in response to the ridge expanding
further westward. Near- to below-normal temperatures are generally favored west
of the Rockies for the period as a whole based on the reforecast consolidation
tool and some support from the analogs. Below-normal temperature chances are
increased for most of Alaska due to a continued unsettled weather pattern and
supported by most forecast tools. Probabilities of above-normal temperatures
are increased across Hawaii, consistent with the consolidation forecast tool.

There are limited synoptic features driving precipitation across the CONUS
during week-2, making for a rather low confidence forecast. Weak probabilities
of above-normal precipitation are forecast across the north-central CONUS, tied
to increasing northwesterly mid-level flow associated with ridging and some
potential for enhanced precipitation moving overtop the ridge. Weak
probabilities of above-normal precipitation are also highlighted over the
Southeast and closer to the Gulf Coast, given the potential for increasing
tropical cyclone activity over the Atlantic during the period, although any
U.S. impacts are highly uncertain at this lead. Above-normal precipitation
chances are slightly elevated across parts of the Southwest, supported by most
forecast tools and enhanced monsoon activity, especially early in the period. A
greater tilt toward enhanced below-normal precipitation chances is favored over
portions of the Great Basin and Rockies, as well as over the Central Plains
through the Midwest, where week-2 precipitation totals are low in the
uncalibrated GEFS and ECENS, and there is little synoptic forcing. An active
pattern is slightly favored to continue into week-2 for much of Alaska,
associated with enhanced westerly mid-level flow. Near- to below-normal
precipitation is more likely across southwestern parts of the state, associated
with increasing mid-level heights. Near- to above-normal precipitation is
favored for Hawaii.

The official 8-14 day 500-hPa height blend consists of: 30% of Today`s 6z 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, due to good
model agreement on the 500-hPa pattern, offset by weak precipitation signals
across much of the forecast domain.

FORECASTER: Thomas Collow

Notes:


Automated forecasts are issued on Saturday and Sunday. Occasionally manual
intervention is necessary to address quality control and consistency issues. In
these cases, forecasts are manually drawn but a full discussion is not issued.


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 (unshaded, "N"). Historical average
values for the calendar period of the forecast (dashes, "f").  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 (unshaded, "n"). Historical median values
for the calendar period of the forecast (dashes, "inches").  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 21.


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:
20030812 - 20070821 - 19930724 - 19910810 - 20010730


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:
20030811 - 20020807 - 19930723 - 19910810 - 19930812


6-10 DAY OUTLOOK TABLE
Outlook for Aug 14 - 18 2025

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



8-14 DAY OUTLOOK TABLE
Outlook for Aug 16 - 22 2025

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

$$