602
FXUS06 KWBC 072030
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Tue January 07 2025

6-10 DAY OUTLOOK FOR JAN 13 - 17 2025

There is good agreement between the latest ECMWF, GEFS, and Canadian ensemble
mean 500-hPa height forecasts on the predicted circulation pattern across North
America for the 6-10 day period. Dynamical models predict changes in the
pattern over time, with large-scale features generally shifting westward during
the period, which is reflected in changes relative to yesterdays forecasts. A
trough is predicted to move northwestward over the Bering Sea and Siberia.
Downstream, models predict a ridge over the North Pacific and positive 500-hPa
height anomalies extending over the Aleutians, Southeast Alaska, and the
northwestern contiguous U.S. (CONUS). Dynamical models continue to predict a
trough and associated negative 500-hPa height anomalies over the eastern half
of the CONUS. Ensemble means consistently predict an extension of the trough
over the southwestern CONUS in the 6-10 day mean forecasts, with some
uncertainty in the location of negative 500-hPa height anomalies among model
solutions.

Above-normal temperatures are likely over central and eastern Mainland Alaska,
under anomalous southerly flow, and over Southeast Alaska, under positive
500-hPa height anomalies. Under the predicted broad trough and negative 500-hPa
height anomalies, below-normal temperatures are likely across a large area of
the CONUS, including the interior West, and from the southern Great Plains
across most of the eastern CONUS excluding the northern Great Lakes and
northern Northeast regions. Near-normal temperatures are favored over some
areas of the West, where temperature tools are inconsistent, under positive
500-hPa height anomalies and anomalous northeasterly flow. Above-normal
temperatures are slightly favored for parts of Montana and the Northern Plains
along the Canadian border, consistent with most dynamical model forecast tools.

Above-normal precipitation is likely across most of Alaska, including the
eastern Aleutians, Mainland Alaska, and Southeast Alaska, east  of the
predicted trough axis. Below-normal precipitation is likely across the western
CONUS, under and ahead of a predicted ridge. Above-normal precipitation is
slightly favored for parts of the Northern Plains and parts of the Southern
Plains consistent with most dynamical model precipitation tools and the
precipitation consolidation. Below-normal precipitation is favored over a large
area of the eastern CONUS, including parts of the Central and Southern
Mississippi Valley, most of the Southeast, and the Eastern Seaboard, under
anomalous northerly flow behind the center of negative 500-hPa height anomalies
over the Atlantic.

Above-normal temperatures and above-normal precipitation are favored for the
Hawaiian Islands, largely due to the influence of positive sea surface
temperature anomalies around the islands.

The official 6-10 day 500-hPa height blend consists of 30% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 15% of Today`s 6z GFS Ensemble Mean centered
on Day 8, 45% of Today`s 0z European Ensemble Mean centered on Day 8, and 10%
of Today`s 0z Canadian Ensemble Mean centered on Day 8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: About average, 3 out of 5, due to
good agreement among the dynamical model height forecasts and an amplified
pattern, offset by differences in temperature and precipitation tools and a
changing pattern.

8-14 DAY OUTLOOK FOR JAN 15 - 21 2025

Dynamical model forecasts from the ECMWF, GEFS and Canadian ensemble means are
in general overall agreement on the average large scale 500-hPa height pattern
in the week-2 period. The GEFS, ECMWF and Canadian ensemble means for the 8-14
day period predict a westward retrogression of the ridge and associated
positive 500-hPa height anomalies over the North Pacific, to be centered over
the Alaska Peninsula, with positive 500-hPa height anomalies predicted across
all of Alaska. Downstream, a trough and negative 500-hPa height anomalies
develop over the western CONUS in the last half of the week-2 period. In the
8-14 day mean manual blend, negative 500-hPa height anomalies persist over the
eastern CONUS, while near-zero anomalies are predicted over most of the West.

Under a changing height pattern, temperature probability forecasts for much of
Alaska decrease in confidence for the 8-14 day period forecast, relative to the
6-10 day period forecast. Above-normal temperatures are favored across most of
Mainland Alaska excluding the southeastern Mainland and Southeast Alaska, under
the predicted ridge. Probabilities of below-normal temperatures continue to be
favored across a large part of the CONUS in week 2, excluding only the upper
Great Lakes region and northern Maine, under a trough and anomalous northerly
flow. Probabilities of below-normal temperatures are elevated across the
western CONUS relative to the 6 to 10 day period, as a trough develops over the
region during week 2.

Above-normal precipitation continues to be favored over most of Mainland
Alaska, excluding the southeast coast, consistent with most dynamical model
forecasts and the precipitation consolidation. Below-normal precipitation is
slightly favored for much of the western CONUS from the Pacific coast to the
Northern and Central Great Basin, consistent with the precipitation
consolidation. Above-normal precipitation is slightly favored from the
Southwest and the Rocky Mountains eastward across most of the Great Plains, as
the trough develops over the West, increasing the chances of precipitation to
the region. Above-normal precipitation is favored for the western Gulf Coast
region and Lower Mississippi Valley, with a precipitation event predicted for
this region later in week 2. A large area of favored near-normal precipitation
is forecast for the eastern CONUS, with differences among the various model
precipitation forecasts. Above-normal precipitation is slightly favored for
parts of the western Great Lakes region and below-normal precipitation is
slightly favored for parts of the Northeast, where model precipitation
forecasts are consistent.

Above-normal temperatures and above-normal precipitation continue to be favored
for the Hawaiian Islands, due to the influence of positive sea surface
temperature anomalies around the islands.

The official 8-14 day 500-hPa height blend consists of: 30% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 15% of Today`s 6z GFS Ensemble Mean centered
on Day 11, 45% of Today`s 0z European Ensemble Mean centered on Day 11, and 10%
of Today`s 0z Canadian Ensemble Mean centered on Day 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Below average, 2 out of 5, due to
good agreement among the dynamical model height forecasts, offset by
differences in temperature and precipitation tools and a rapidly changing
mid-level height pattern forecast.

FORECASTER: D Collins

Notes:


Automated forecasts are issued on Saturday and Sunday. Occasionally manual
intervention is necessary to address quality control and consistency issues. In
these cases, forecasts are manually drawn but a full discussion is not issued.


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 (unshaded, "N"). Historical average
values for the calendar period of the forecast (dashes, "f").  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 (unshaded, "n"). Historical median values
for the calendar period of the forecast (dashes, "inches").  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
January 16.


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:
20001227 - 19770116 - 19850118 - 19951222 - 19850109


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:
20001227 - 19951228 - 19951222 - 19850118 - 19850109


6-10 DAY OUTLOOK TABLE
Outlook for Jan 13 - 17 2025

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



8-14 DAY OUTLOOK TABLE
Outlook for Jan 15 - 21 2025

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

$$