185
FXUS06 KWBC 172001
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Fri January 17 2025

6-10 DAY OUTLOOK FOR JAN 23 - 27 2025

A highly amplified 500-hPa height pattern is forecast across the forecast
domain at the outset of the 6-10 day period, with ridging over western North
America and strong troughing downstream over the eastern half of the CONUS.
This troughing is forecast to quickly lift out by the middle of the period,
with the 0z ECENS and CMCE reloading the troughing across the west-central
CONUS by day-10 and increasing positive height anomalies along the Eastern
Seaboard. The manual height blend indicates above-normal heights along the West
Coast of the CONUS and extending northward through Alaska, with +210 meter
positive height anomaly to the south of Alaska. Below-normal heights are
predicted for most of the remainder of the CONUS given the initial troughing in
the East and the trend toward additional troughing in the Interior West later
in the period. Slightly above-normal heights are forecast across the Southeast
and southern Mid-Atlantic. Troughing forecast over the central Pacific favors
near- to below-normal heights across Hawaii for the period as a whole.

The Arctic air outbreak across the eastern CONUS is forecast to be abating at
the start of the period, although daily temperature anomalies of at least -10
deg F are depicted in the 0z ECENS and GEFS along parts of the Eastern Seaboard
on day-6 (Jan 23). A short period of above-normal temperatures is favored
across portions of the Northern Plains and Upper Midwest before the troughing
reloads at the end of the period ushering in another round of relatively colder
temperatures. Elevated probabilities of below-normal temperatures are favored
across much of the CONUS, but with reduced probabilities compared to yesterday,
and near-normal across the Upper Midwest given the transient pattern.
Near-normal temperatures are also forecast across parts of the Southwest, with
the reforecast tools continuing to indicate a warmer outcome compared to the
uncalibrated guidance. Ridging favors high chances for above-normal
temperatures over Mainland Alaska and the Aleutians, with near-normal
temperatures forecast for Southeast Alaska due to increasing offshore winds.
The consolidation forecast tool supports enhanced probabilities for
above-normal temperatures across Hawaii.

Multiple shortwaves are forecast to move across the central and eastern CONUS
throughout the period. This results in elevated chances for above-normal
precipitation across portions of the Southern Plains, Middle and Lower
Mississippi Valley, Tennessee Valley, Mid-Atlantic, and Southeast, with near-
to slightly above-normal precipitation more likely for the Great Lakes and
Northeast. Winter weather is a concern over some of these areas depending on
the northern stream interaction. A transition to more troughing in the West
toward the end of the period supports enhanced odds for above-normal
precipitation across parts of the Rockies and High Plains. Near-to below normal
precipitation probabilities remain elevated for much of the West Coast, Four
Corners, and southern High Plains given a relatively drier regime still favored
at the start of the period. Increased southerly flow along with weak troughing
over the Bering Sea favors elevated chances of above-normal precipitation over
most of Alaska, with the highest chances across the northwestern Mainland due
to the projected northward shift in the storm track and reduced precipitation
climatology in this region. Above-normal precipitation is favored across Hawaii.

The official 6-10 day 500-hPa height blend consists of 30% of Today`s 6z GFS
Ensemble Mean centered on Day 8, 35% of Today`s 0z European Ensemble Mean
centered on Day 8, and 35% of Today`s 0z Canadian Ensemble Mean centered on Day
8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Average, 3 out of 5, due to very
good model agreement at the start of the period, offset by a potential
mid-level pattern realignment later in the period.

8-14 DAY OUTLOOK FOR JAN 25 - 31 2025

A realignment of the 500-hPa height pattern is forecast to continue during
week-2, with the 0z ECENS, GEFS, and CMCE building positive height anomalies
over the East, troughing over western North America, and a retrogression of the
ridge across the East Pacific. This would also be consistent with the
background La Nina state and active MJO over the Indian Ocean. The manual
height blend for week-2 depicts below-normal heights across much of the western
and central CONUS and New England, and above-normal heights over parts of the
Southeast, Mid-Atlantic, Tennessee and Ohio Valleys, and lower Northeast.
Above-normal heights continue to be depicted over Alaska underneath ridging.
Near- to slightly below-normal heights remain favored for Hawaii due to a
variable height pattern.

Enhanced chances for below-normal temperatures are forecast across most of the
CONUS during week-2, although regional variation in temperatures are likely
throughout the period as the mid-level pattern realigns. Overall, there is a
general trend toward below-normal temperatures in the West and closer to normal
temperatures in the East, although additional transient bursts of cold air are
possible especially across the Northern Tier as depicted in the 0z ECENS. The
repositioning of the ridge axis over the Bering Sea supports a relatively
colder pattern developing across Alaska as the period progresses. A slight tilt
toward above-normal temperatures is favored across much of the Mainland and
Aleutians for the period as a whole, with elevated chances for below-normal
temperatures over the far northwestern Mainland and Southeast Alaska. The
consolidation forecast tool supports enhanced odds for above-normal
temperatures across Hawaii.

The retrogression of the ridge combined with troughing developing over the
west-central CONUS supports increasing near- to above-normal precipitation
chances over much of the West, with daily precipitation totals increasing
across parts of California later in the period. As in the 6-10 day period,
there remains high uncertainty regarding the storm track in the East, with the
degree of northern and southern stream interaction influencing the surface low
strength and track, along with any impactful winter weather. The overall
pattern supports broad coverage of enhanced above-normal precipitation
probabilities. Above-normal precipitation probabilities remain elevated over
Mainland Alaska, but a drying trend is forecast as the ridge becomes more
centered over the Bering Sea. As a result of this, along with increasing
northerly mid-level flow, near-normal precipitation is favored across Southeast
Alaska. Above-normal precipitation is forecast over Hawaii.

The official 8-14 day 500-hPa height blend consists of: 30% of Today`s 6z GFS
Ensemble Mean centered on Day 11, 35% of Today`s 0z European Ensemble Mean
centered on Day 11, and 35% 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
a predicted mid-level pattern shift during the period and a more transient
surface pattern emerging.

FORECASTER: Thomas Collow

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
February 20.


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:
19661228 - 19800123 - 20080116 - 20020114 - 20090110


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:
20080117 - 20090123 - 19570103 - 20020114 - 19910120


6-10 DAY OUTLOOK TABLE
Outlook for Jan 23 - 27 2025

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



8-14 DAY OUTLOOK TABLE
Outlook for Jan 25 - 31 2025

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

$$