318
FXUS06 KWBC 022045
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Tue December 02 2025

6-10 DAY OUTLOOK FOR DEC 08 - 12 2025

The GEFS, ECENS, and CMCE are in good agreement with an amplified longwave
500-hPa pattern which features a ridge (trough) along the West (East) Coast.
This ridge-trough pattern is being anchored by an upstream Aleutian ridge and
trough across eastern Mainland Alaska. Due to this amplified longwave pattern
over Alaska and the contiguous U.S. (CONUS), temperature tools are in excellent
agreement and forecast confidence is high in the 6-10 day temperature outlook.
The amplified trough along the East Coast with substantial negative 500-hPa
height anomalies favor below-normal temperatures from the Mississippi Valley to
the East Coast. Compared to yesterday, a minor two-category change from above
to below-normal temperatures was warranted for the Florida Peninsula as cold
air advection results in colder-than-normal temperatures by days 6 and 7
(December 8 and 9). The anomalous cold is likely to peak on day 6 when the
ECENS depicts daily temperature anomalies of more than -20 degrees F across New
England. Conversely, the amplified ridge with positive 500-hPa height anomalies
support an increased chance of above-normal temperatures from the West Coast to
the Great Plains.

Drier-than-normal conditions are favored for most of the southern half of the
CONUS, due to the anomalous mid-level ridge upstream along the West Coast and
broad surface high pressure. Since precipitation, associated with a cold front,
is expected to time off by day 6, a two-category change (above to below-normal
precipitation) was necessary for parts of the Southeast. The one exception to
the southern tier dryness is the lower Rio Grande Valley and south Florida as a
stationary front may lead to above-normal precipitation. Multiple shortwave
troughs, within the amplified longwave trough along the East coast, could spawn
surface low pressure systems either across the Mid-Atlantic and/or Northeast.
It is uncertain how intense these surface lows could become. Given their
predicted fast movement, precipitation amounts should be limited and only a
slight lean towards above-normal is forecast for eastern New England. Farther
to the west, lake-effect snow and upslope flow favor above-normal precipitation
downwind of the Great Lakes and across the Central Appalachians. Enhanced
Pacific flow, to the north of the West Coast ridge, favors above-normal
precipitation across the Pacific Northwest east to the Northern Great Plains
and Upper Mississippi Valley.

The amplified longwave pattern is likely to promote Arctic high pressure
overspreading Mainland Alaska where below-normal temperatures and precipitation
are favored. The consolidation (skill weighted GEFS and ECENS reforecast
calibration) depicts a very large spatial extent with more than a 70 percent
chance of below-normal temperatures across the southern half of Mainland
Alaska. For southeastern Alaska, elevated above-normal precipitation
probabilities are slightly elevated due to more onshore flow.

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 30% of Today`s 0z 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 on an amplified longwave pattern.

8-14 DAY OUTLOOK FOR DEC 10 - 16 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
favor changes to this pattern across the lower 48 states during mid-December.
Later in week-2, the amplified trough is forecast to shift away from the East
Coast with increasing 500-hPa heights over the eastern CONUS. Meanwhile, the
anomalous 500-hPa ridge over the western CONUS is forecast to be replaced with
a mid-level trough. The ECENS is the fastest with this transition across the
lower 48 states. The longwave pattern over Alaska is more stable with an
amplified 500-hPa ridge persisting over the Aleutians and Bering Sea with a
trough downstream across eastern Mainland Alaska.

Due in large part to the anomalously cold temperatures early in week-2,
below-normal temperatures are favored for much of the eastern CONUS.
Below-normal temperature probabilities decrease across the Southeast as the
ECENS and GEFS depict temperatures either moderating or flipping to above from
December 14-16. The mid-level ridge with positive 500-hPa height anomalies to
start week-2 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 upstream over the Aleutians,
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 may eventually shift
or expand southward by the end of week-2.

Dynamical model output along with the analog tool derived from the manual
500-hPa height blend are in good agreement with 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 much 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 official 8-14 day 500-hPa height blend consists of: 30% of Today`s 0z 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
agreement in the evolving longwave pattern offset by a predicted temperature
change across the Southeast and potential for Arctic air to shift south into
the northern Great Plains later in week-2.

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 - 20071125 - 19881208 - 20021203 - 19761127


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:
19781125 - 20071126 - 20081203 - 19761130 - 20021203


6-10 DAY OUTLOOK TABLE
Outlook for Dec 08 - 12 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    A    A     S DAKOTA    A    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    A
ILLINOIS    B    N     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    A     CONN        B    A     RHODE IS    B    A
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    B     GEORGIA     B    B
FL PNHDL    B    B     FL PENIN    B    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    A



8-14 DAY OUTLOOK TABLE
Outlook for Dec 10 - 16 2025

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

$$