900
FXUS06 KWBC 042002
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Thu December 04 2025

6-10 DAY OUTLOOK FOR DEC 10 - 14 2025

The GEFS, ECENS, and CMCE are in good agreement that a strengthening
full-latitude 500-hPa ridge over the Aleutians and Bering Strait anchors an
amplified and stable longwave pattern throughout North America. The multi-model
ensemble mean solutions continue to depict a broad ridge over the southwestern
contiguous U.S. (CONUS) and a downstream anomalous trough centered along the
East Coast. Due to the amplified and stable longwave pattern, forecast
confidence remains high in the 6-10 day temperature outlook with little change
from previous days. Multiple outbreaks of anomalous cold are forecast to
overspread the Great Lakes, Midwest, and Northeast during early to
mid-December. The amplified trough along the East Coast with substantial
negative 500-hPa height anomalies favor below-normal temperatures from the
Middle and Upper Mississippi Valley to the East Coast. Below-normal temperature
probabilities were increased across the Midwest due to the likelihood that
anomalous snow cover persists into next week. The mid-level ridge with positive
500-hPa height anomalies support an increased chance of above-normal
temperatures from the West Coast to the Central and Southern Great Plains.Later
in this period, Arctic air building over Alaska may start to shift
southeastward into the northern Great Plains. Therefore, forecast confidence is
lower for this region and temperature probabilities for either below or
above-normal temperatures are less than 50 percent.

A vigorous shortwave trough and associated surface low are forecast to track
eastward from the Upper Mississippi Valley and Great Lakes to the Northeast on
days 6 and 7 (December 10 and 11), which favors above-normal precipitation for
these areas. In the wake of this low pressure system, strong cold air advection
is likely to enhance precipitation amounts downwind of the Great Lakes along
with upslope flow across the Central Appalachians. Strong Pacific flow supports
an increased chance of above-normal precipitation from the Pacific Northwest
east to the Northern Rockies and Northern Great Plains. Drier-than-normal
conditions are favored for most of the southern half of the CONUS, due to the
anomalous mid-level ridge centered upstream across the Southwest and broad
surface high pressure. The one exception to the southern tier dryness is the
lower Rio Grande Valley and south Florida as a stationary front may lead to
near or above-normal precipitation.

The amplified longwave pattern is likely to promote a long duration of
entrenched Arctic high pressure across Mainland Alaska where below-normal
temperatures and precipitation are favored. The consolidation (skill weighted
GEFS and ECENS reforecast calibration) depicts a large spatial extent with more
than a 70 percent chance of below-normal temperatures across the southeast
quarter of Alaska.

Based on the GEFS and ECENS, above-normal temperatures and above-normal
precipitation are favored for Hawaii.

The official 6-10 day 500-hPa height blend consists of 35% of Today`s 6z GFS
Ensemble Mean centered on Day 8, 35% 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 on an amplified and stable longwave pattern.

8-14 DAY OUTLOOK FOR DEC 12 - 18 2025

Multi-model ensemble mean solutions continue to depict a slow eastward shift of
the amplified 500-hPa trough, initially along the East Coast. Despite a
predicted increase in 500-hPa heights from the 6-10 to 8-14 day period, a
significant warmup is not anticipated for the Mid-Atlantic and Northeast as
anomalous northerly flow continues through the end of week-2. To the south of
the Carolinas, temperatures are forecast to moderate and could even flip to
above-normal from December 16-18. Given this predicted evolution of the pattern
and based on the temperature tools, the largest below-normal temperature
probabilities (60 percent or more) are forecast from New England south to the
northern Mid-Atlantic. These probabilities decrease across the Carolinas and
Georgia with near normal temperatures more likely for most of Florida.
Anomalous northerly surface flow also favors below-normal temperatures across
the Great Lakes, Middle to Upper Mississippi Valley, and Northern Great Plains.
For the third day in a row, a teleconnection upon the predicted large positive
500-hPa height anomaly center near the Bering Strait led to hedging colder than
the dynamical model output for the northern tier of the western CONUS. Forecast
confidence is increasing that at least shallow Arctic air shifts south into
Montana and North Dakota early in week-2. However, anomalous cold is not
expected to overspread the remainder of the West at least through December 18.
Based on this and good model agreement including the analog tool derived from
the manual 500-hpa height blend, above-normal temperatures are favored for much
of the West, Central to Southern Great Plains, and the Lower Mississippi
Valley. The largest above-normal temperature probabilities (70 percent or more)
are forecast across the Great Basin, Southwest, and southern California.

Dynamical model output along with the aforementioned teleconnection guidance
generally depicts favored wetness (dryness) across the northern (southern) tier
of the CONUS. Similar to the 6-10 day outlook, the one exception to the dryness
across the southern tier is southern portions of Florida and Texas where a
stationary front could tilt the outcome towards the wet side. Through at least
the beginning of week-2, strong cold air advection is likely to enhance
precipitation downwind of Lakes Erie and Ontario. To the east of the
Appalachians, the analog tool derived from the manual 500-hPa height blend
along with the uncalibrated model output supports elevated below-normal
precipitation probabilities along the East Coast. Due to enhanced Pacific flow
persisting through much of week-2, above-normal precipitation probabilities are
largest (50 percent or more) from the Pacific Northwest east to the Northern
Rockies. One notable trend the past few days is for an expansion of favored
wetness south along the West Coast to northern California which is consistent
with an amplifying 500-hPa trough over the northeastern Pacific and the analog
tool.

Due to the full-latitude ridge over the Aleutians and Bering Strait,
colder-than-normal temperatures along with near to below normal precipitation
is favored throughout Alaska. The ECENS and GEFS depict the most anomalous cold
shifting to southeastern Alaska by mid-December as cross-polar flow becomes
maximized and Arctic high pressure prevails. Later in week-2, there are signs
that temperatures may begin to moderate across the North Slope of Alaska.

Based on the GEFS and ECENS, an increased chance of above-normal temperatures
and above-normal precipitation are forecast for Hawaii. Positive sea surface
temperature anomalies also support above-normal temperatures, especially across
the northwestern islands. The favored wetness is consistent with the ongoing La
Nia.

The official 8-14 day 500-hPa height blend consists of: 35% of Today`s 6z GFS
Ensemble Mean centered on Day 11, 35% 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 consistency and what is likely to be an amplified, stable longwave
pattern through mid-December.

FORECASTER: Brad Pugh

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:
20081205 - 19911202 - 20071128 - 19981218 - 20051117


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:
20081205 - 20001207 - 19911202 - 20071127 - 20221120


6-10 DAY OUTLOOK TABLE
Outlook for Dec 10 - 14 2025

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



8-14 DAY OUTLOOK TABLE
Outlook for Dec 12 - 18 2025

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

$$