747
FXUS06 KWBC 122002
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Tue November 12 2024

6-10 DAY OUTLOOK FOR NOV 18 - 22 2024

Today`s ensemble mean solutions are in good agreement on predicting a highly
amplified mean 500-hPa flow pattern across North America and surrounding
regions (particularly in the beginning of the period). High amplitude troughs
are predicted over Alaska and the western contiguous U.S. (CONUS) at the start
of the 6-10 day period. Mid-level heights are predicted to rise over Alaska
during the period, as the trough amplifies over the northeastern Pacific. The
predicted trough downstream over the CONUS progresses eastward across the CONUS
during the period and deamplifies slightly. The 500-hpa manual blend weights
the European slightly greater than other models, due to recent skill evaluation.

Below normal temperatures are favored for most of Alaska, excluding parts of
northern and southeastern Alaska, due to the amplified trough over the state
early in the period. Below normal temperatures are likely for most of the
western half of the CONUS, excluding parts of the Northern Plains, under the
amplified trough early in the period. Probabilities for below normal
temperatures are lower over the northwestern CONUS in the 6-10 day forecast,
where tools are less certain. Above normal temperatures are likely for the
eastern CONUS in the 6-10 day period, due to an anomalous ridge and positive
500-hPa height anomalies, especially early in the period. Near normal
temperatures are forecast for Hawaii, where 500-hPa height anomalies are weak
and tools are inconsistent.

The progression of an amplified trough from the western CONUS eastward favors a
large area of above normal precipitation across much of the central CONUS.
Probabilities of above normal precipitation exceed 50 percent for parts of the
Central Plains near the predicted mean baroclinic zone. Above normal
precipitation is slightly favored into parts of the eastern CONUS, as flow
around surface high pressure in the Atlantic may bring subtropical moisture
into the area. Above normal precipitation is slightly favored for much of
Alaska as cyclonic flow is forecast over the state for most of the period. Near
normal precipitation is favored for Hawaii, with weak anomalies in
precipitation tools.

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
good agreement among the dynamical model height forecasts and an amplified
pattern early in the period, offset by some differences in temperature and
precipitation tools and a rapidly changing pattern.

8-14 DAY OUTLOOK FOR NOV 20 - 26 2024

During the week-2 period, dynamical models predict a rapid evolution of the
predicted 500-hPa height pattern, leading to greater uncertainty among
temperature and precipitation tools. A trough predicted over the central CONUS
at the start of the period is forecast to quickly progress across the eastern
CONUS by the GEFS model in particular, while the ECMWF ensemble mean predicts a
slightly slower eastward progression. The ridge over the western CONUS at the
start of week 2 deamplifies somewhat during the period. Positive 500-hPa height
anomalies are predicted over Alaska in week 2.

Above normal temperatures are favored for northern and eastern Mainland Alaska
and southeastern Alaska, as a trough deamplifies and mid-level heights rise
across the state. Below normal temperatures are favored across a large area of
the western and central CONUS for the week-2 period, with the predicted
progression of a trough. There is some disagreement among dynamical model
temperature tools on the extent of below normal temperatures for the Southeast,
where near normal is favored in the outlook. Above normal temperatures continue
to be favored for the Midwest, Mid-Atlantic and Northeast, consistent with most
dynamical model temperature tools. Near normal temperatures are favored for
Hawaii where temperature tools are inconsistent.

With cyclonic flow progressing eastward across the CONUS, areas of enhanced
probabilities of above normal precipitation are confined to parts of the
north-central and northeastern CONUS. Above normal precipitation is also
favored for the Florida Peninsula, where precipitation tools are relatively
consistent. Below normal precipitation is slightly favored across the western
CONUS extending into the Lower Mississippi Valley, as models forecast a drier
pattern in week 2. Persistent cyclonic flow 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 a rapidly 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:
19751103 - 19521101 - 19981025 - 19831030 - 20091104


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:
19751104 - 19771025 - 19831030 - 19861122 - 19601115


6-10 DAY OUTLOOK TABLE
Outlook for Nov 18 - 22 2024

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



8-14 DAY OUTLOOK TABLE
Outlook for Nov 20 - 26 2024

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

$$