294
FXUS06 KWBC 142001
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 14 2025

6-10 DAY OUTLOOK FOR JAN 20 - 24 2025

A highly amplified 500-hPa height pattern is forecast across the forecast
domain during the 6-10 day period, with ridging over western North America and
strong troughing downstream east of the Rockies. The 0z ECENS and CMCE are
quicker to lift the troughing out in the East by day-10 while the 0z GEFS
maintains stronger negative height anomalies. The manual height blend indicates
above-normal heights west of the Rockies and extending northward through
Alaska. A +210 meter positive height anomaly center is noted just to the west
of British Columbia. Below normal heights are predicted for most of the CONUS
east of the Rockies, with the strongest negative anomalies (-150 meters) to the
north of the Great Lakes. Slightly above-normal heights are forecast across the
Florida Peninsula, further downstream from the mean trough axis. A variable
mid-level height pattern is forecast across the Central Pacific and Hawaii,
although more troughing may begin to take shape later in the period.
Near-normal heights are forecast across the islands for the period as a whole.

A major Arctic air outbreak is forecast to be ongoing across the central and
eastern CONUS at the start of the period. The 0z ECENS and GEFS indicate
widespread daily temperature anomalies exceeding -20 deg F on days 6 and 7,
corresponding with subzero temperatures across the Northern and Central Plains,
Midwest, and possibly into the Interior Northeast, and minimum temperatures in
the 20s deg F possibly reaching the Gulf of Mexico coast. The reforecast and
uncalibrated tools all support elevated probabilities for below-normal
temperatures across nearly all of the CONUS, with the highest chances (greater
than 80 percent) across the Southern Plains and much of the East. Probabilities
for below-normal temperatures are reduced across the Northern Plains due to the
possibility of quickly moderating temperatures as the trough lifts out, with
the ECENS depicting a flip to above-normal temperatures at the end of the
period. Increasing downslope winds slightly favor near- to above-normal
temperatures across portions of California, southern Oregon, and western
Nevada. Ridging supports high chances for above-normal temperatures over
Alaska. The consolidation forecast tool supports enhanced probabilities for
above-normal temperatures across Hawaii, but with reduced probabilities to the
north due to the potential for troughing to develop over the region.

The amplified mid-level pattern leads to a generally confident precipitation
forecast, with better model agreement compared to yesterday regarding a more
suppressed storm track in the East. Therefore, the highest chances for
above-normal precipitation are highlighted across the Gulf Coast and coastal
Southeast. However, given the cold air in place, there is some concern for
wintry weather over some of these areas, as evidenced by the deterministic 12z
GFS and ECMWF. Enhanced chances for below-normal precipitation are favored
across parts of the Great Plains extending through the Mid-Atlantic and
Northeast tied to incoming surface high pressure and anomalous northerly
mid-level flow. Elevated lake effect snow chances slightly tilts the odds
toward above-normal precipitation across the Great Lakes. Anomalous ridging
across the West supports high chances for below-normal precipitation from the
Rockies to the Pacific Coast, with occasional shortwaves moving overtop the
ridge axis and on the backside of the downstream troughing leading to enhanced
chances for above-normal precipitation across the northern High Plains.
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 35% of Today`s 6z GFS
Ensemble Mean centered on Day 8, 5% of Today`s operational 6z GFS centered on
Day 8, 35% of Today`s 0z European Ensemble Mean centered on Day 8, 5% of
Today`s operational 0z ECMWF centered on Day 8, and 20% of Today`s 0z Canadian
Ensemble Mean centered on Day 8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Well above average, 5 out of 5,
due to very good model agreement regarding an amplified mid-level pattern over
the forecast domain and a major Arctic outbreak across the eastern half of the
U.S.

8-14 DAY OUTLOOK FOR JAN 22 - 28 2025

The 500-hPa height pattern during week-2 remains fairly persistent with that of
the 6-10 day period, with some decrease in amplitude in the longwave features.
There continues to be some signs of an MJO-induced pattern change toward the
end of the period, with the 0z ECENS, GEFS, and CMCE building positive height
anomalies over the East, and the longwave trough possibly reloading but
centered more over the west-central CONUS. This would also be more consistent
with the background La Nina state. The manual height blend for week-2 depicts
below-normal heights across most of the CONUS east of the Rockies, with the
exception being over parts of the Southeast where weakly above-normal heights
are indicated. Above-normal heights continue to be depicted west of the Rockies
and extending northward through Alaska underneath ridging. Near-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 swings in temperatures are likely
throughout the period as the mid-level pattern realigns. At the start of the
period, the largest negative temperature anomalies are predicted over the
eastern U.S., with an upward trend in temperatures across portions of the
Northern Plains and Upper Midwest. This moderation is forecast to spread
eastward, and the 0z ECENS and GEFS depict a flip to above-normal temperatures
in the East by the end of week-2. However, the reloading trough further west
favors a return to colder temperatures across the Northern Rockies and Plains
late in the period. The GEFS and ECENS reforecast tools support enhanced
probabilities of above-normal temperatures across the Southwest tied to ridging
and increasing downslope winds, with higher probabilities extending through
Alaska. The consolidation forecast tool supports enhanced odds for above-normal
temperatures across Hawaii.

Troughing lifting out supports a more northward extension of increased
above-normal precipitation chances in week-2 relative to the prior period,
which is consistent with the ECENS and GEFS reforecast tools. The deterministic
12z GFS and ECMWF depict a wave of surface low pressure bringing wintry weather
to parts of the Southeast and possibly further north early in the period.
Elevated probabilities for above-normal precipitation are highlighted over most
of the Great Plains, Middle and Lower Mississippi Valley, Tennessee Valley, and
Southeast. Near- to slightly below normal precipitation is favored over the
Northeast, with Lake elevated Effect Snow chances continuing to tilt the odds
to above-normal across the Great Lakes. The retreating ridge over western North
America may increase precipitation chances along parts of the West Coast by the
end of the period, with near-normal precipitation favored for the Northwest and
slightly below-normal precipitation remaining forecast over the Southwest. The
reforecast tools support enhanced chances for above-normal precipitation across
Alaska, with above-normal precipitation odds also remaining elevated across
Hawaii.

The official 8-14 day 500-hPa height blend consists of: 40% of Today`s 6z GFS
Ensemble Mean centered on Day 11, 40% of Today`s 0z European Ensemble Mean
centered on Day 11, and 20% 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 regarding the mid-level height pattern, offset by decreasing
amplification and some uncertainty in the evolution toward the end of the
period.

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
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:
19661228 - 19691230 - 19550110 - 19751231 - 19710105


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:
19691229 - 19661228 - 19751231 - 19550109 - 19710104


6-10 DAY OUTLOOK TABLE
Outlook for Jan 20 - 24 2025

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



8-14 DAY OUTLOOK TABLE
Outlook for Jan 22 - 28 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  B    N     OREGON      N    N     NRN CALIF   A    B
SRN CALIF   N    B     IDAHO       B    N     NEVADA      A    N
W MONTANA   B    A     E MONTANA   B    A     WYOMING     B    A
UTAH        B    N     ARIZONA     B    B     COLORADO    B    A
NEW MEXICO  B    N     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    N
INDIANA     B    N     OHIO        B    N     KENTUCKY    B    A
TENNESSEE   B    A     ALABAMA     B    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    N
MARYLAND    B    N     DELAWARE    B    N     VIRGINIA    B    N
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

                           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.

$$