485
FXUS06 KWBC 302009
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Thu January 30 2025

6-10 DAY OUTLOOK FOR FEB 05 - 09 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 an amplified ridge
over Mainland Alaska, a downstream trough over the northwestern contiguous U.S.
(CONUS), and a ridge over the southeastern CONUS. Positive 500-hPa height
anomalies are predicted across the southern tier and eastern CONUS, excluding
parts of the Northeast, as well as across Alaska, by recent ensemble means of
the GEFS, ECMWF and Canadian models. Negative 500-hPa height anomalies are
predicted over the northwestern CONUS. Run-to-run continuity has been quite
good for the last several days, increasing forecast confidence.

Above normal temperatures are likely for the Aleutians and most of Mainland
Alaska, under a predicted ridge. Near to below normal temperatures are favored
for parts of Southeast Alaska, under anomalous northerly flow. Below normal
temperatures are likely for the West Coast across the Northern Rockies into the
Northern Plains, under negative 500-hPa height anomalies. Above normal
temperatures are likely across the southern CONUS and up the East Coast, as
well as the southern Great Basin, under positive 500-hPa height anomalies.
Above normal temperatures are slightly favored for the Hawaiian Islands with
local sea surface temperatures above long term averages.

Above normal precipitation is favored for the northwestern coast of Mainland
Alaska, with some light precipitation expected under onshore flow. Below normal
precipitation is favored for the south coast of Mainland Alaska and Southeast
Alaska, under the predicted ridge and predominately northerly flow. Over the
CONUS, near to above normal precipitation is broadly favored with a progressive
trough moving over the northern CONUS. Below normal precipitation is favored
for parts of the Southwest and Florida, under positive 500-hPa height
anomalies. Near normal precipitation is favored for most of Hawaii with the
exception of the Big Island, which tilts towards above normal precipitation.

The official 6-10 day 500-hPa height blend consists of 40% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 40% of Today`s 0z European Ensemble Mean
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: Above average, 4 out of 5, due to
good agreement among the dynamical model height forecasts and an amplified
pattern, offset by small differences in some areas in temperature and
precipitation tools and a progressive pattern.

8-14 DAY OUTLOOK FOR FEB 07 - 13 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. A ridge persists over Alaska through the 8-14 day period
with some eastward progression and deamplification, while a trough is predicted
over the northwestern CONUS. Positive 500-hPa height anomalies continue to be
predicted over the southern tier and eastern half of the CONUS in the 8-14 day
period. Todays ensemble mean from the Canadian model diverges substantially
from earlier solutions, as well as todays solutions from the ECMWF and GEFS,
and therefore is weighted less in the 500-hPa manual blend for todays 8-14 day
period.

The temperature pattern across Alaska in the 8-14 day period is similar to the
pattern in the 6-10 day period forecast, with lower probabilities as
uncertainty increases. Above normal temperatures are favored over the Aleutians
and much of Mainland Alaska, with below normal temperatures favored for parts
of Southeast Alaska. A progressive trough moving from the Pacific Northwest
into the Great Plains leads to likely below normal temperatures for much of the
western and central CONUS. Above normal temperatures remain favored for
portions of the Southern Tier and extending up the East Coast into the
Mid-Atlantic region under persistent positive height anomalies.

Below normal precipitation is favored for southern Mainland Alaska under
anomalous northerly flow while lingering onshore flow tilts the odds towards
above normal precipitation for northwestern Alaska. A trough progressing across
the western and central CONUS in dynamical model forecasts leads to enhanced
probabilities for above normal precipitation across most of the CONUS
particularly over the Ohio Valley where an enhanced baroclinic zone is
depicted. Parts of the Southwest and Florida remain favored for near to below
normal precipitation.

Above normal temperatures and above normal precipitation are favored across the
Hawaiian Islands, with above average sea surface temperatures surrounding the
islands and consistent with the precipitation consolidation.

The official 8-14 day 500-hPa height blend consists of: 42% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 43% of Today`s 0z European Ensemble Mean
centered on Day 11, and 15% of Today`s 0z Canadian Ensemble Mean centered on
Day 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: About average, 3 out of 5, due to
reasonable agreement among the dynamical model height forecasts, offset by
differences in temperature and precipitation tools in some areas, some
progression of the mid-level height pattern during the period, and diverging
solutions particularly from the Canadian ensemble.

FORECASTER: Daniel Barandiaran

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:
19760205 - 20030212 - 19910121 - 19890210 - 19940118


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:
19940118 - 19760205 - 19620128 - 20030212 - 19710131


6-10 DAY OUTLOOK TABLE
Outlook for Feb 05 - 09 2025

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



8-14 DAY OUTLOOK TABLE
Outlook for Feb 07 - 13 2025

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

                           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.

$$