857
FXUS06 KWBC 152002
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Mon December 15 2025

6-10 DAY OUTLOOK FOR DEC 21 - 25 2025

Dynamical models are in good agreement regarding a significant pattern change
across much of the eastern half of the U.S. during the week of Christmas.
Mid-level ridging is forecast to amplify over the CONUS east of the Rockies
with troughing over Canada and extending along the West Coast. Today`s 500-hPa
manual height blend for the 6-10 day period depicts above-normal heights across
much of the CONUS, with the exceptions being over the Pacific Northwest,
northern California, northern Great Basin, and New England, where below-normal
heights are indicated. A persistent ridge is favored across Alaska with a +390
meter positive height anomaly center depicted to the south of the Aleutians in
the manual blend, and above-normal heights extending over much of the
southwestern Mainland. Below-normal heights remain forecast for eastern and
southeastern Alaska closer to the troughing over Canada. Near-normal 500-hPa
heights are forecast across Hawaii as troughing over the central Pacific is
predicted to weaken.

Widespread above-normal temperature probabilities are favored throughout most
of the CONUS during the period, bringing in a welcome reprieve from colder
weather experienced early in December over much of the eastern U.S. in time for
the holiday week. However, some pause is given to the northward extent of the
warmth given the predicted weakening of the positive Arctic Oscillation (+AO)
along with the potential development of a negative North Atlantic Oscillation
(-NAO). Both would favor near to below-normal temperatures across the Northern
Tier into the Northeast, which is reflected in some of the uncalibrated and
short-term bias corrected temperature tools. Deep ridging across the Aleutians
and associated northerly mid-level flow over Alaska favors high probabilities
of below-normal temperatures across much of Mainland and Southeast Alaska. This
is supported by uncalibrated and reforecast tools, in addition to
teleconnection analysis with the positive height anomaly center south of the
Aleutians. Conversely, odds for above-normal temperatures are increased over
the Aleutians and the far western Mainland. High probabilities of above-normal
temperatures are forecast for Hawaii, consistent with the consolidation
reforecast tool.

Above-normal precipitation probabilities are increased over the western and
north-central CONUS tied to continued atmospheric river activity. The highest
probabilities (greater than 80 percent) are favored across central California
where several inches of rain and high elevation snow are possible. Enhanced
odds for above-normal precipitation also extend into portions of southern
California and western Arizona as troughing off the West Coast further
amplifies with additional support from teleconnection and analog guidance.
Ridging downstream favors elevated probabilities for below-normal precipitation
across parts of the Central and Southern Plains, Gulf Coast, Southeast, and
Mid-Atlantic. Continued impulses of northern stream energy favor near-normal
precipitation across portions of the Ohio Valley and Northeast. Over Alaska,
offshore flow supports elevated chances of below-normal precipitation across
southern and southeastern parts of the state, while a more northward oriented
storm track favors elevated chances for above-normal precipitation over the
northern two-thirds of the Mainland. Probabilities for above-normal
precipitation are increased across northwestern Hawaii, with near-normal
precipitation more favored to the south and east.

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 model agreement regarding the mid-level pattern, offset by some
uncertainty regarding the northern extent of above-normal temperatures across
the CONUS.

8-14 DAY OUTLOOK FOR DEC 23 - 29 2025

The 500-hPa height pattern discussed in the 6-10 outlook is likely to persist
into week-2. The 0z ECMWF, GEFS, and Canadian ensembles depict the troughing
off the West Coast peaking in amplitude early in week-2 before beginning to
weaken and lift northward. This evolution continues to favor enhanced
atmospheric river activity across California and the Southwest early in the
period and shifting back into the Pacific Northwest later in week-2.
Downstream, high-amplitude ridging is favored over the east-central CONUS, with
the week-2 manual height blend depicting positive height anomalies over most
areas from the Rockies to the Eastern Seaboard. Below-normal heights are
depicted across parts of the western CONUS, northern New England, and eastern
Alaska, with above-normal heights indicated over western Alaska tied to a
persistent ridge axis centered over the western Aleutians. Near-normal heights
are forecast across Hawaii, although rising mid-level heights are possible
across the northern islands later in the period as positive height anomalies
originating over Alaska expand further southward over the Pacific.

Dominant mid-level ridging continues to favor unseasonably warm temperatures
across much of the CONUS during week-2, with the highest probabilities (greater
than 90 percent) over the Southern Plains. The strongest signals for
below-normal temperatures remain across the Pacific Northwest and and New
England where a more cyclonic flow pattern is predicted with greater influence
from troughing. As discussed in the 6-10 day outlook, the extent of warm
temperatures across the Northern Tier is more uncertain due to competing
influences from the ridge and high-latitude teleconnections and increased
northern stream energy which would support a cooler pattern. The potential
re-emergence of the Madden Julian Oscillation (MJO) into phase 8 in late
December may also lead to a downward trend in temperatures by the last week of
December. Therefore, some caution is given to the forecast, with a larger area
of near-normal temperatures predicted over the Northern Plains, Upper
Mississippi Valley, Great Lakes, and northern Mid-Atlantic. Anomalously cold
weather is favored to persist across most of Alaska tied to the ridging
upstream over the Aleutians. The highest chances for below-normal temperatures
are forecast across the southeastern portion of the state, consistent with the
ECMWF and GEFS reforecast tools. Conversely, high probabilities for
above-normal temperatures remain favored across Hawaii based on the
consolidated reforecast tool.

Above-normal precipitation probabilities are increased from the West Coast of
the CONUS eastward to the Rockies associated with continued atmospheric river
activity. Early in the period, the strongest moisture advection is favored
across California and the Southwest, with a northward retreat back into the
Pacific Northwest more likely later in week-2. Ridging favors a much drier
pattern across the central and southeastern CONUS, with below-normal
precipitation chances increased over these areas. An active northern stream
supports slightly elevated chances for above-normal precipitation over the
Northern Plains, through parts of the Midwest, Ohio Valley, Great Lakes, and
Northeast. Reforecast tools are in good agreement supporting continued enhanced
below-normal precipitation chances over southern Alaska, with above-normal
precipitation more likely over the northern Mainland. Odds for above-normal
precipitation are slightly increased over most of Hawaii, with near-normal
precipitation favored over the Big Island.

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: Above average, 4 out of 5, due to
good model agreement regarding the placement of amplified features.

FORECASTER: Thomas Collow

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
December 18.


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:
20101210 - 19951125 - 19951130 - 20121125 - 20131215


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:
19951125 - 20101211 - 19951130 - 20131214 - 20121125


6-10 DAY OUTLOOK TABLE
Outlook for Dec 21 - 25 2025

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



8-14 DAY OUTLOOK TABLE
Outlook for Dec 23 - 29 2025

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

$$