189
FXUS06 KWBC 212001
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 21 2024

6-10 DAY OUTLOOK FOR NOV 27 - DEC 01, 2024

During the 6-10 day period models remain in fairly good agreement relative to
yesterday on an amplified and progressive mid-level height pattern across North
America and the surrounding regions. Strong positive 500-hPa height anomalies
are forecast to be centered over the Gulf of Alaska consistent with yesterday.
Meanwhile, a fast moving mid-level trough is forecast to progress from the
Interior West and bring mid-level troughing to much of the contiguous U.S.
(CONUS) during the 6-10 day period.

This week has seen the gradual erosion of above-normal temperature
probabilities across the eastern and southeastern CONUS in each successive
forecast and today is no exception. Above-normal temperature probabilities are
limited to the Rio Grande Valley and the Gulf Coast during the 6-10 day period.
Below-normal temperature chances are widespread across the CONUS with the
strongest probabilities in the Northern and Central Plains, exceeding 80%.
Below-normal probabilities have also expanded into the Northeast and
Mid-Atlantic today, relative to yesterday. In Alaska, forecast guidance from
the GEFS generally favors warmer than normal conditions, while the ECENS
generally favors cooler than normal conditions. The deterministic GFS would
also favor below-normal conditions across much of interior Alaska. As such,
Near- to below-normal is favored in much of Mainland Alaska and Southeast
Alaska, with above-normal limited to southwestern Mainland and the Aleutians.
In Hawaii, tools are in agreement for above-normal temperatures across much of
the archipelago, excluding the Big Island where near-normal temperatures are
favored.

A generally wet pattern is predicted across the CONUS along and east of the
Rocky Mountains during the 6-10 day period. The strongest chances are across
portions of the Central Rockies and into the Central Plains. The more easterly
progression of the mid-level trough reduces chances for above-normal
precipitation along the immediate West Coast and into the Great Basin relative
to yesterday and broad below-normal precipitation is favored in these areas. As
the trough progresses east, an associated surface low pressure may develop and
bring enhanced precipitation to portions of the Ohio and Tennessee Valleys.
Much of this rain is forecast to fall on days 6 and 7 before drying out for the
second half of the period. In Alaska, broad near-normal precipitation is
forecast today with mixed signals and small anomalies forecast across much of
the state. The best chances for above-normal precipitation are along the
south-central and southeast Mainland, while below-normal precipitation is
favored along the northwestern coast. Near- to below-normal precipitation is
favored in Southeast Alaska with mid-level high pressure to the West. In
Hawaii, below-normal precipitation is favored consistent with reforecast and
bias-corrected tools.

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. Good
agreement among the dynamical and statistical tools is offset by a progressive
and shifting pattern.

8-14 DAY OUTLOOK FOR NOV 29 - DEC 05, 2024

The progressive mid-level trough is forecast to move east across the CONUS
early in week-2 and then stall across portions of the northeastern CONUS by the
end of the week. Positive mid-level heights are forecast off the West Coast and
across much of Alaska bringing northwesterly flow across the eastern CONUS for
much of week-2. The enhanced positive mid-level anomalies across the Gulf of
Alaska brings southwesterly flow over Mainland Alaska.

Below-normal temperature chances are forecast for much of the CONUS during
week-2 beneath mid-level troughing and northwesterly flow aloft. Above-normal
temperature chances for the CONUS are limited to portions of southern Florida.
The strongest probabilities for below-normal temperatures are favored across
portions of the Northern Plains through the Midwest and into the Mid-Atlantic.
In the southwestern CONUS, reforecast tools generally have lower chances for
below-normal temperatures relative to yesterday. Short-term bias-corrected
tools continue to forecast below-normal temperature chances. Therefore,
near-normal temperatures are favored in portions of Arizona and New Mexico with
a slight tilt towards below in other portions of the southwestern CONUS. In
Alaska, near-normal temperatures are favored for much of Mainland Alaska. The
southwesterly flow pattern aloft brings chances for above-normal temperatures
aloft but a complicating factor in the surface forecast is the potential for
low-level inversions to develop due to the low solar heating at this time of
year, reducing the confidence in above-normal temperature chances. Therefore,
above-normal temperature chances are limited to coastal areas of southern
Alaska. Below-normal is favored in portions of Southeast Alaska. In Hawaii,
above-normal temperatures remain forecast consistent with the available
guidance.

The precipitation outlook for the CONUS is more confident relative to yesterday
with better agreement between the GEFS and ECENS. Below-normal precipitation is
favored for much of the West Coast, Great Basin, and Desert Southwest with
mid-level ridging upstream limiting onshore flow. Above-normal precipitation
remains favored for the Northern and Central Rockies and the Northern and
Central Plains with unsettled weather beneath a mid-level trough. Further east,
across the Central Mississippi region, an area of below-normal precipitation is
favored. There is good agreement among the dynamical tools for a rapid drying
out following a wet day 6 and 7. Above-normal is again favored for portions of
the Southern Atlantic states with a frontal system still possibly moving
through the region at the onset of week-2. In Alaska, below-normal
precipitation is favored for the northwestern portions of the state with
above-normal precipitation favored for southeastern portions of Mainland
Alaska. Near-normal is favored for Southeast Alaska. In Hawaii, near-normal
precipitation is generally favored for much of the state.

The official 8-14 day 500-hPa height blend consists of: 30% of Today`s 6z GFS
Ensemble Mean centered on Day 11, 40% 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, with
divergent solutions among the model guidance for temperature and precipitation
reducing confidence.

FORECASTER: Ryan Bolt

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
December 19.


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:
19631111 - 19731127 - 19731113 - 19611125 - 19961119


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:
19631114 - 19731127 - 19731112 - 19631109 - 20051130


6-10 DAY OUTLOOK TABLE
Outlook for Nov 27 - Dec 01, 2024

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



8-14 DAY OUTLOOK TABLE
Outlook for Nov 29 - Dec 05, 2024

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

$$