307
FXUS06 KWBC 222030
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Wed January 22 2025

6-10 DAY OUTLOOK FOR JAN 28 - FEB 01, 2025

Today`s numerical models depict a complex 500-hPa flow pattern across much of
the forecast domain. The period begins with strong ridging near the western
Aleutians, anomalous troughing over western Mainland Alaska, and a positively
tilted ridge extending from offshore of the Pacific Northwest to southwestern
Canada. A strong trough is forecast over the northeastern CONUS and a cutoff
low is depicted over the Southwest. As time progresses, the ridge over
southeast Canada / Pacific Northwest is forecast to quickly progress across the
CONUS and weaken. In its wake, the strong trough over western Mainland Alaska
is forecast to progress across the remainder of the Mainland and toward
Southeast Alaska by the end of the period. The cutoff low over the Southwest is
forecast to weaken and slowly progress eastward. The strong trough over the
Northeast is generally predicted to progress eastward and off the coast by the
end of the period, allowing heights to rise in its wake. The 500-hPa manual
height blend, based primarily on the ensemble means from the ECMWF, GEFS, and
Canadian models, depicts above normal heights across the Aleutians as well as
the northwestern, central, and southeastern CONUS. Below normal heights are
forecast for most of Mainland and Southeast Alaska, Northeast, and parts of the
Southwest.

Below normal temperatures are likely across much of Alaska, as a trough builds
and progresses across the state. Probabilities of anomalous cold exceed 70
percent across southwestern Mainland Alaska. Below normal temperatures are
favored for the southwestern CONUS due to the cutoff low predicted nearby.
Enhanced near normal temperatures are favored for most of the remainder of the
West as transient ridging off the West Coast early in the period pushes inland.
A tilt toward below normal temperatures is indicated for the Northeast and
northern Mid-Atlantic, as anomalous troughing progresses through the region.
Conversely, as this trough departs, height rises in its wake support increased
probabilities of above normal temperatures across much of the north-central
CONUS. Above normal temperatures are favored for southern Florida and the Gulf
Coast region underneath slightly positive mean 500-hPa heights. Above normal
temperatures are likely across Hawaii consistent with above normal sea surface
temperatures in adjacent waters.

As the predicted trough deepens across Alaska, enhanced moisture flow ahead of
it promotes increased chances of above-normal precipitation across eastern
parts of the state. As this trough progresses eastward, enhanced moisture flow
is expected to push southward into the northwestern CONUS, resulting in
increased chances of above normal precipitation. Below normal precipitation is
favored farther to the south from the southern half of West Coast eastward
across the central Great Basin, the central Rockies, parts of the northern and
central Plains, and parts of the Midwest, as the predicted transient ridge
progresses eastward. Above normal precipitation is favored for much of the
southern third of the CONUS from parts of the Southwest eastward to the
southern Atlantic Coast. Probabilities of above normal precipitation exceed 50
percent across parts of the southern Plains due to potential return flow
moisture on the backside of  predicted high pressure over the Southeast and
ahead of the weakening cutoff low over the Southwest. Slightly enhanced
probabilities of above-normal precipitation are indicated for parts of the
northern Great Lakes and interior Northeast underneath predicted cyclonic flow.
Above normal precipitation is also slightly favored for Hawaii associated with
a mean trough forecast to the west of the state.

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: Average, 3 out of 5, due to fairly
good agreement on an amplified pattern early in the period offset by increased
model spread as time progresses.

8-14 DAY OUTLOOK FOR JAN 30 - FEB 05, 2025

After observing a negative NAO and AO for much of the first half of January,
models are generally predicting a positive phase of both indices during the
week-two period. This potential transition is illustrated by predicted below
normal heights across most of the higher latitudes of North America and above
normal heights across much of the mid-latitudes. Confidence in the transition
of the NAO to the positive phase is growing, likely resulting in increased
ridging over much of the eastern CONUS. The transition to a positive AO and NAO
typically results in a moderation of the overall flow pattern and less Arctic
air intrusions across much of the CONUS. However, with anomalous ridging
continuing to be forecast across the higher latitudes of the Eastern
Hemisphere, this may allow for a more southward displacement of below normal
heights than typical with a positive AO and NAO. The period begins with strong
troughing over Alaska and the northeastern CONUS. The Alaska trough is then
forecast to progress southeastward, resulting in the potential for increased
troughing over the northwestern and north-central CONUS with time. In its wake,
a ridge over the Aleutians is forecast to slowly move eastward, resulting in
height rises across western Mainland Alaska toward the end of the period.
Farther to the east, increased ridging is forecast for the Southeast as the
trough over the Northeast departs off the coast. The mean 500-hPa height blend
depicts above normal heights across most of the southern two-thirds of the
CONUS as well as western Alaska. Below normal heights are forecast across
eastern Alaska, parts of the Pacific Northwest, northern Rockies, and northern
High Plains, and northern New England, with near normal heights favored across
the remainder of the Northern Tier of the CONUS.

A significant Arctic outbreak is likely for most of Alaska with enhanced
probabilities of below normal temperatures indicated for almost the entire
state with the lone exception being the  Aleutians. Probabilities of below
normal temperatures exceed 70 percent for parts of the southeastern Mainland
near the predicted mean trough axis. Confidence is lower across the western
CONUS due to a predicted transient pattern. Near to above normal temperatures
are modestly favored from central California eastward across much of the
interior West associated with predicted transient ridging. Confidence is
increasing for a transition to a positive NAO, increasing the odds of above
normal temperatures for the southeastern quadrant of the CONUS extending
northwestward to much of the Midwest and Plains. A slight tilt toward below
normal temperatures are indicated for the Northeast, particularly early in the
period, due to a departing trough. Below normal temperatures are also favored
for much of the Pacific Northwest and parts of the Northern Rockies and
northern High Plains as strong troughing initially over Alaska pushes to the
south and east later in the period. A slight tilt toward below normal
temperatures is indicated for parts of southern California  and southwestern
Arizona due to potential residual effects from the cutoff low forecast early in
the period. Conversely, above normal temperatures are likely for Hawaii, due,
in part, to above normal SSTs in adjacent waters.

As a deep trough progresses across Alaska, a drying trend is anticipated across
the western Mainland and the Alaska Peninsula underneath northerly flow,
supporting enhanced chances of below normal precipitation. Above normal
precipitation is favored for Southeast Alaska, ahead of the trough axis as well
as northeastern Mainland Alaska underneath anomalous northerly flow. As the
trough progresses southeastward, increased onshore flow is likely to shift
farther to the south across the west coast of North America. This potential
southward shift increases probabilities of above normal precipitation across
the northwestern CONUS. A slight tilt toward above normal precipitation is
indicated eastward across the Northern Tier, near a potential mean baroclinic
zone close to the CONUS/Canada border. Increased chances of above normal
precipitation is also indicated from the western Gulf Coast region,
northeastward across the Lower Mississippi Valley, Tennessee Valley, Ohio
Valley, and parts of the Mid-Altantic due to potential moisture advection
around the backside of predicted ridging over the Southeast. A slight tilt
toward below normal precipitation is indicated for the southern Florida
Peninsula closer to the predicted ridge. Conversely, a slight tilt toward above
normal precipitation is indicated for Hawaii, due to a predicted trough in the
vicinity.

The official 8-14 day 500-hPa height blend consists of: 25% of Today`s 6z GFS
Ensemble Mean centered on Day 11, 45% 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: Below Average, 2 out of 5, due to
model disagreements on the evolution of a predicted transitional pattern across
much of the forecast domain.

FORECASTER: Scott H

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:
19940201 - 19910121 - 19940115 - 20080120 - 19990103


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:
19940115 - 19940131 - 19910121 - 19990104 - 20080120


6-10 DAY OUTLOOK TABLE
Outlook for Jan 28 - Feb 01, 2025

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



8-14 DAY OUTLOOK TABLE
Outlook for Jan 30 - Feb 05, 2025

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

                           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.

$$