977
FXUS06 KWBC 142010
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Thu November 14 2024

6-10 DAY OUTLOOK FOR NOV 20 - 24 2024

Today`s ensemble mean solutions are in good agreement on predicting an
amplified mean 500-hPa flow pattern across North America and surrounding
regions. A high amplitude ridge is predicted over the Aleutian Islands, while a
trough is predicted downstream over the northeastern Pacific Ocean in 6-10 day
mean forecasts. As the trough progresses eastward over the Pacific towards the
west coast during the period, a second trough is predicted to move across the
eastern contiguous U.S. (CONUS). The GEFS model progresses the pattern more
rapidly eastward than the ECMWF model, shifting 500-hPa height anomalies
further east in the GEFS relative to the ECMWF forecast. A ridge and associated
positive 500-hPa height anomalies are predicted over the northwestern CONUS for
the 6-10 day period, with primarily anomalous northerly flow into the interior
West.

Above normal temperatures are favored for northwestern Mainland Alaska,
consistent with positive 500-hPa height anomalies and decadal temperature
trends, while near normal is favored over the remainder of the state, where
temperature forecast tools are inconsistent. Above normal temperatures are
favored along the west coast of the CONUS under anomalous southerly flow,
consistent with the consolidation of GEFS and ECMWF temperature forecasts.
Below normal temperatures are favored for the interior West and much of the
southern CONUS, under primarily northerly mid-level flow associated with a
ridge to the northwest and under a trough and associated negative 500-hPa
height anomalies to the east. Above normal mean temperatures are favored for
the Great Lakes region, Mid-Atlantic and Northeast in the 6-10 day period, with
warmer temperatures primarily in the first half of the period related to
positive 500-hPa height anomalies. Near normal temperatures are forecast for
Hawaii, where ECMWF and GEFS tools are inconsistent.

Above normal precipitation is favored for central and northern Mainland Alaska,
under strong westerly mid-level flow. Near to below normal precipitation is
favored for most of the western CONUS, under a predicted ridge, and for the
south-central CONUS under anomalous northerly flow. Above normal precipitation
is favored for parts of the Northern Plains, the Midwest, and the East, with a
trough predicted to progress across the eastern CONUS. Above normal
precipitation is slightly favored for Hawaii, consistent with the precipitation
consolidation.

The official 6-10 day 500-hPa height blend consists of 35% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 45% 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: About average, 3 out of 5, due to
general agreement on the overall circulation forecast, offset by a changing
pattern and differences among the model temperature and precipitation tools.

8-14 DAY OUTLOOK FOR NOV 22 - 28 2024

The changing 500-hPa height pattern forecast continues into the week-2 period,
with increasing differences between models and deamplification of most
anomalies. The GEFS continues to be more progressive with an eastward shift in
the large-scale wave pattern relative to the ECMWF. The ECMWF forecast was
again given greater weight than other models, due to recent skill. The manual
500-hPa height blend predicts positive 500-hPa height anomalies across Alaska
and a ridge centered over the Aleutians. A predicted trough over the
northeastern Pacific approaches the west coast of the CONUS in week 2. The
manual blend predicts mean positive 500-hPa height anomalies over the western
CONUS and negative 500-hPa height anomalies over most of the eastern CONUS,
associated with an amplified trough early in the period that deamplifies over
time.

Above normal temperatures are slightly favored for central and northern Alaska
in week 2, under positive mid-level height anomalies. Above normal temperatures
are slightly favored for the West, consistent with reforecast-calibrated GEFS
and ECMWF forecasts. Below normal temperatures are favored from the Southern
and Central Plains into the Ohio Valley and Southeast, under a predicted mean
trough. Above normal temperatures continue to be favored for the northern Great
Lakes region and parts of the Northeast, supported by most dynamical model
temperatures forecasts. Near normal temperatures are favored for Hawaii where
temperature tools are inconsistent.

Above normal precipitation is favored across much of Mainland Alaska,
consistent with most dynamical model forecasts. With a predicted trough exiting
the eastern CONUS and weaker mid-level height anomalies, areas of slightly
enhanced probabilities of above normal precipitation are confined to parts of
the north-central CONUS. Near normal precipitation is favored for the
Northeast, where tools are inconsistent. Above normal precipitation is also
favored for the southern Florida Peninsula, where precipitation tools are
relatively consistent. Below normal precipitation is favored across a large
area of the southern CONUS, under a drier pattern behind the eastward
progressing trough. Above normal precipitation is slightly favored for parts of
California as a trough is predicted to approach the coast during the period.
The precipitation consolidation favors above normal precipitation across
Hawaii.

The official 8-14 day 500-hPa height blend consists of: 35% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 45% 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: Below average, 2 out of 5, due to
model forecast differences on an evolving mid-level height pattern.

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
November 21.


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:
20081102 - 20091119 - 20091108 - 19721107 - 19621127


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:
20091108 - 20051031 - 19721106 - 20081101 - 19561027


6-10 DAY OUTLOOK TABLE
Outlook for Nov 20 - 24 2024

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



8-14 DAY OUTLOOK TABLE
Outlook for Nov 22 - 28 2024

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

$$