575
FXUS06 KWBC 052002
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Fri December 05 2025

6-10 DAY OUTLOOK FOR DEC 11 - 15 2025

Today`s numerical models are in good agreement in depicting a very amplified
500-hPa flow pattern across North America and vicinity. An unusually strong
ridge (with positive height departures greater than 390 meters) is forecast
over the Bering Sea. Downstream troughing is forecast over southeastern Alaska
and a strong ridge is forecast over the western CONUS. Large scale anomalous
troughing is forecast over most of eastern North America. This overall pattern
is very similar to that forecast yesterday, with today`s solution representing
even more amplification of the large scale features. Farther away from North
America, slightly below normal 500-hPa heights are forecast for Hawaii, on the
southern fringe of broadly cyclonic flow over the central Pacific.

Below normal temperatures are likely across much of the eastern and
north-central CONUS due to strong and persistent troughing. Probabilities of
below normal temperatures exceed 80 percent across much of the Great Lakes
Region and adjacent areas of the Northeast and northern Mid-Atlantic.
Conversely, expansive ridging across the West favors above normal temperatures.
With this ridge coming in stronger today relative to yesterday, chances of
warmer than normal temperatures exceed 90 percent for parts of the Great Basin
and adjacent areas of the Southwest. Conversely, a cold pattern is likely for
much of Alaska due to anomalous northerly flow ahead of the predicted unusually
strong Bering Sea Ridge. Chances of below normal temperatures are greater than
80 percent for Southeast Alaska and adjacent areas of the southeastern
Mainland. Above normal temperatures are favored for Hawaii, consistent with
dynamical model output and with above normal SSTs in the adjacent Pacific.

An active pattern is favored for the northwestern and north-central CONUS as
enhanced Pacific flow is forecast ahead of a mean trough forecast near
southeastern Alaska. Below normal precipitation is likely across most of the
southern two-thirds of the CONUS due to a combination of anomalous mid-level
ridging across much of the West and mean surface high pressure across much of
the East. The area of favored below normal precipitation extends northward
along much of the Eastern Seaboard as a surface low departs offshore of New
England near the start of the period. In the wake of this system, strong
northerly or northwesterly low-level flow is forecast over the Great Lakes,
setting up the potential for enhanced Lake Effect snow. A tilt toward above
normal precipitation is indicated for much of the Great Lakes region due to
this potential. Farther to the south, a slight tilt toward above normal
precipitation is indicated for extreme southern Florida and southern Texas,
near the southern periphery of the predicted trough over eastern North America.
Conversely, below normal precipitation is likely for much of Alaska consistent
with predicted northerly offshore flow ahead of the very strong ridge over the
Bering Sea. Above normal precipitation is favored for Hawaii near the southern
periphery of predicted broad cyclonic flow over the central Pacific and
consistent with dynamical model guidance.

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: Much above average, 5 out of 5,
due to good model agreement and consistency on a highly amplified 500-hPa flow
pattern across North America and vicinity.

8-14 DAY OUTLOOK FOR DEC 13 - 19 2025

The unusually high amplitude 500-hPa flow pattern is forecast to persist into
the first half of week-2 with uncertainty increasing significantly thereafter.
The period starts off with continued strong ridging across the Bering Sea and
the western CONUS. Strong troughing is forecast across the eastern CONUS and
enhanced Pacific flow is forecast to continue across the northwestern CONUS. As
we enter the second half of week-2, the flow pattern becomes more murky. The 0z
ECMWF ensemble mean develops a strong trough over the central Plains later in
week-2 while the GEFS predicts a more zonal pattern. Meanwhile the 0z Canadian
ensemble mean persists the western ridge and eastern trough throughout the
entire period. Due to the uncertainties present during the latter half of week
two, the mean 500-hPa pattern for the seven day period is very representative
of the predicted pattern during the first half of the period, where models are
in better agreement. This mean 500-hPa pattern is very similar to yesterday,
with anomalous ridging over the Bering Sea and western CONUS and troughing over
the northeastern CONUS and Southeast Alaska. As was the case with the 6 to 10
day mean, today`s week-2 500-hPa mean is slightly more amplified with the
overall features relative to yesterday. This reflects the potential for a very
amplified pattern during the first half of the period. Generally near normal
mean heights are forecast for Hawaii, as broad troughing to its north
retrogrades westward and further away from the state.

Below normal temperatures are favored for the northeastern quadrant of the
CONUS as well as adjacent areas of the Southeast and Northern Plains.
Probabilities of below normal temperatures exceed 70 percent across the
Northeast as well as much of the Great Lakes region. This represents an
increase in confidence relative to yesterday as today`s model solutions depict
slightly stronger negative height departures in the mean 500-hPa field.
Conversely, above normal temperatures are favored for the southwestern,
northwestern, and south-central CONUS due to predicted expansive ridging.
Probabilities of above normal temperatures exceed 80 percent across much of the
Southwest and Great Basin. This represents an increase in coverage relative to
yesterday as model solutions have trended stronger with the ridge across the
West. Below normal temperatures remain favored for much of Alaska with the
greatest confidence (more than 80 percent) predicted across parts of Southeast
Alaska. Enhanced northerly flow and below normal 500-hPa heights are expected
to continue well into week-2 across this region. Above normal temperatures are
favored for Hawaii, consistent with dynamical model output and with above
normal SSTs in the adjacent Pacific.

Enhanced Pacific flow is expected to persist across the northwestern CONUS well
into week-2. As a result, above normal precipitation is favored for the Pacific
Northwest, Northern Rockies, Northern Plains, and northern California. The
southern extent of this region of favored above normal precipitation has
retreated northward relative to yesterday, reflecting the trend toward a
stronger ridge across the western CONUS. Correspondingly, increased confidence
for below normal precipitation (greater than 50 percent) is indicated for the
Southwest, closer to the center of the predicted ridge. This ridge is predicted
to expand eastward during the early to middle part of the period, resulting in
increased confidence for dryness eastward across much of the central and
southern Plains and Lower Mississippi Valley. Predicted surface high pressure,
particularly early in the period, favors below normal precipitation across most
of the Eastern Seaboard. Enhanced Lake Effect snow is still possible,
especially during the early portion of week-2, leading to a tilt toward above
normal precipitation for most areas adjacent to the Great Lakes. A tilt toward
above normal precipitation persists for southern Florida and southern Texas
near the southern periphery of the broad trough forecast over eastern North
America. Conversely, a dry pattern is favored for much of Alaska, underneath
mean offshore flow ahead of the predicted Bering Sea ridge. Above normal
precipitation is favored for Hawaii near the southeastern fringe of predicted
broad cyclonic flow over the Pacific and consistent with dynamical model
guidance.

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 an amplified 500-hPa pattern during the first half of week-2
offset by a significant increase in model uncertainty thereafter.

FORECASTER: Scott H

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:
20081206 - 19911203 - 20131211 - 20041219 - 19981218


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:
20081206 - 19911202 - 20131211 - 20001207 - 20221120


6-10 DAY OUTLOOK TABLE
Outlook for Dec 11 - 15 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   N    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    B     W TEXAS     A    B
MINNESOTA   B    A     IOWA        B    N     MISSOURI    B    B
ARKANSAS    N    B     LOUISIANA   N    B     WISCONSIN   B    N
ILLINOIS    B    B     MISSISSIPPI B    B     MICHIGAN    B    A
INDIANA     B    N     OHIO        B    N     KENTUCKY    B    B
TENNESSEE   B    B     ALABAMA     B    B     NEW YORK    B    N
VERMONT     B    N     NEW HAMP    B    N     MAINE       B    N
MASS        B    B     CONN        B    B     RHODE IS    B    B
PENN        B    B     NEW JERSEY  B    B     W VIRGINIA  B    B
MARYLAND    B    B     DELAWARE    B    B     VIRGINIA    B    B
N CAROLINA  B    B     S CAROLINA  B    B     GEORGIA     B    B
FL PNHDL    B    B     FL PENIN    N    N     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



8-14 DAY OUTLOOK TABLE
Outlook for Dec 13 - 19 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    N
W MONTANA   A    A     E MONTANA   N    A     WYOMING     A    N
UTAH        A    B     ARIZONA     A    B     COLORADO    A    B
NEW MEXICO  A    B     N DAKOTA    B    A     S DAKOTA    B    N
NEBRASKA    N    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    B
ARKANSAS    N    B     LOUISIANA   A    B     WISCONSIN   B    A
ILLINOIS    B    N     MISSISSIPPI N    B     MICHIGAN    B    A
INDIANA     B    N     OHIO        B    N     KENTUCKY    B    B
TENNESSEE   B    B     ALABAMA     N    B     NEW YORK    B    N
VERMONT     B    B     NEW HAMP    B    B     MAINE       B    N
MASS        B    B     CONN        B    B     RHODE IS    B    B
PENN        B    N     NEW JERSEY  B    B     W VIRGINIA  B    N
MARYLAND    B    B     DELAWARE    B    B     VIRGINIA    B    B
N CAROLINA  B    B     S CAROLINA  B    B     GEORGIA     B    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    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.

$$