477
FXUS06 KWBC 032002
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Wed December 03 2025

6-10 DAY OUTLOOK FOR DEC 09 - 13 2025

The GEFS, ECENS, and CMCE are in good agreement that a strengthening 500-hPa
ridge over the Aleutians and Bering Strait anchors a high amplitude longwave
pattern throughout North America. The multi-model ensemble mean solutions
continue to depict a broad ridge over the western contiguous U.S. (CONUS) and a
downstream anomalous trough near the East Coast. Due to the amplified longwave
pattern, temperature tools are in excellent agreement and forecast confidence
is high in the 6-10 day temperature outlook. Multiple outbreaks of anomalous
cold are forecast to overspread the Great Lakes, Midwest, and Northeast during
the next week to ten days. During this 5-day time period, the largest daily
temperature anomalies (-10 to -20 degrees F) are forecast to affect the
Northeast on day 6, December 9. 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. Conversely, the
amplified 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. Beginning on day 8 or 9, 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
a favored category are less than 50 percent.

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 the Florida Peninsula as a
stationary front may lead to near or above-normal precipitation. A vigorous
shortwave trough is forecast to track eastward from the Upper Mississippi
Valley and Great Lakes to the Northeast during this period, which favors
above-normal precipitation for these areas. Precipitation amounts are likely to
be enhanced downwind of the Great Lakes and with upslope flow along 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.

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 southern half
of Mainland Alaska. For extreme southern areas of southeastern Alaska,
above-normal precipitation probabilities are slightly elevated due to onshore
flow early in the period.

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 longwave pattern.

8-14 DAY OUTLOOK FOR DEC 11 - 17 2025

The longwave ridge (trough) along the West (East) Coast is forecast to persist
through the beginning of week-2. However, multi-model ensemble mean solutions
are consistent that the amplified mid-level trough shifts away from the East
Coast later in week-2 with increasing 500-hPa heights over the southeastern
CONUS. Meanwhile, 500-hPa heights are forecast to decrease across the western
CONUS as a mid-level trough amplifies over the higher latitudes of western
North America. The longwave pattern over Alaska is more stable due to the
persistent full-latitude ridge extending from the Aleutians north to the Bering
Strait. The GEFS, ECENS, and CMCE are in excellent agreement that a large
positive 500-hPa height anomaly center (7-day mean of more than 200 meters)
develops near the Bering Strait. Given the excellent model agreement, a
teleconnection upon this anomaly center was used as a guide in the week-2
temperature and precipitation outlooks.

Although the high amplitude 500-hPa trough is forecast to shift away from the
East Coast later in week-2, cross-polar flow with anomalous northwesterly
surface flow favors below-normal temperatures for much of the eastern CONUS.
Below-normal temperature probabilities decrease across the Southeast as model
solutions feature a more variable temperature pattern south of the 40th
parallel. The mid-level ridge with positive 500-hPa height anomalies increases
the chance for above-normal temperatures across the western and south-central
CONUS. Based on a teleconnection upon the predicted large positive 500-hPa
height anomaly center near the Bering Strait, above-normal temperature
probabilities depicted in the dynamical model output were reduced across the
northern tier of the West along with the Northern to Central Great Plains.
Forecast confidence in the temperature outlook is lowest for these areas as the
Arctic air building across Alaska is expected to expand south into the lower 48
states but its southward extent remains uncertain.

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 early in week-2 could tilt the outcome towards the wet side.
Above-normal precipitation probabilities are largest (40 to 50 percent, or
more) for the Pacific Northwest, northern Rockies, and northern Plains due to
enhanced Pacific flow affecting those areas.

Overall across Alaska, colder-than-normal temperatures accompanied by near to
below normal precipitation is favored during week-2. The ECENS and GEFS depict
the anomalous cold peaking early in week-2 as cross-polar flow becomes
maximized and Arctic high pressure prevails. Even with anomalous cold easing
later in this period as it may begin to shift southeastward towards the lower
48 states, 7-day temperatures are forecast to average more than 10 degrees F
below normal for the southern two-thirds 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: Average, 3 out of 5, due to good
agreement in the evolving longwave pattern offset by uncertainty on if and when
Arctic air building over Alaska expands or shifts southward into the Northern
Rockies and Northern Great Plains.

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:
20081204 - 19881208 - 19781127 - 20071125 - 19761126


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:
19781126 - 20081205 - 20071126 - 19761201 - 19881210


6-10 DAY OUTLOOK TABLE
Outlook for Dec 09 - 13 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    A    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    A     MISSOURI    B    B
ARKANSAS    A    B     LOUISIANA   A    B     WISCONSIN   B    A
ILLINOIS    B    N     MISSISSIPPI N    B     MICHIGAN    B    A
INDIANA     B    A     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    A     CONN        B    A     RHODE IS    B    A
PENN        B    A     NEW JERSEY  B    A     W VIRGINIA  B    A
MARYLAND    B    N     DELAWARE    B    N     VIRGINIA    B    N
N CAROLINA  B    N     S CAROLINA  B    B     GEORGIA     B    B
FL PNHDL    B    B     FL PENIN    B    N     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    A



8-14 DAY OUTLOOK TABLE
Outlook for Dec 11 - 17 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    A     OREGON      A    A     NRN CALIF   A    A
SRN CALIF   A    B     IDAHO       A    A     NEVADA      A    B
W MONTANA   A    A     E MONTANA   B    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    B     KANSAS      A    B     OKLAHOMA    A    B
N TEXAS     A    B     S TEXAS     A    N     W TEXAS     A    B
MINNESOTA   B    A     IOWA        B    N     MISSOURI    B    N
ARKANSAS    A    B     LOUISIANA   A    B     WISCONSIN   B    A
ILLINOIS    B    N     MISSISSIPPI A    B     MICHIGAN    B    A
INDIANA     B    A     OHIO        B    A     KENTUCKY    B    N
TENNESSEE   B    N     ALABAMA     N    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    A
MARYLAND    B    N     DELAWARE    B    B     VIRGINIA    B    N
N CAROLINA  B    B     S CAROLINA  B    B     GEORGIA     B    B
FL PNHDL    N    N     FL PENIN    N    A     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

                           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.

$$