713
FXUS06 KWBC 072001
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 07 2024

6-10 DAY OUTLOOK FOR NOV 13 - 17 2024

The GEFS, ECENS, and CMCE remain consistent that a 500-hPa trough amplifies
over the western contiguous U.S. (CONUS) during the period. A transient
shortwave trough is forecast to shift offshore of the East Coast on day 8 with
a building ridge across the east-central CONUS. The amplifying 500-hPa trough
with negative 500-hPa height departures support increased chances for
below-normal temperatures across California, the Great Basin, and Desert
Southwest. The GEFS and ECENS reforecast tools are in better agreement today
with near to above-normal temperatures favored for the Pacific Northwest and
Northern Intermountain West. From the Great Plains to the East Coast, predicted
mean southerly flow during this 5-day period favors above-normal temperatures.
A blocking ridge over the North Atlantic may lead to a strengthening low
pressure system near southeastern New England on day 8. Although ensemble
spread is large on the strength and location of this low pressure system, there
could be a brief period of cold air advection and only a slight lean towards
above or near normal temperatures are forecast for New England.

Multi-model ensemble solutions are in good agreement and consistent that a low
pressure system and trailing front progress eastward from the Mississippi
Valley to the East Coast on days 6 and 7. Near to above-normal precipitation is
favored for the Great Lakes, Ohio Valley, and Northeast. The ECENS continues to
back off on its heavier precipitation amounts with this frontal passage east of
the Appalachians, especially south of the 40th parallel. Given this consistent
model trend the past few days which better aligns with the preferred GEFS
reforecast tool and NAEFS, the precipitation outlook leans towards below-normal
precipitation for most of the Mid-Atlantic and Southeast. A two-category change
from yesterday with a slight lean towards above shifting to below-normal
precipitation is warranted for the Southeast as precipitation times off by day
6. The amplifying trough over the western CONUS supports increased above-normal
precipitation probabilities for this region along with the Great Plains and
Middle to Upper Mississippi Valley.

Westerly flow slightly favors above-normal temperatures across the Aleutians
and coastal southwestern Alaska, while anomalous cold through day 8 tilts the
outlook towards below-normal temperatures for portions of southeastern Alaska.
A strong low pressure system is expected to track from the Bering Sea to
southeastern Alaska which favors above-normal precipitation throughout Alaska.

Based on the GEFS and ECENS, above-normal temperatures and above-normal
precipitation are favored for Hawaii.

The official 6-10 day 500-hPa height blend consists of 35% of Today`s 6z GFS
Ensemble Mean centered on Day 8, 35% 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: Above average, 4 out of 5, due to
good model agreement on the evolving longwave pattern and improved agreement on
the precipitation outlook for the eastern CONUS.

8-14 DAY OUTLOOK FOR NOV 15 - 21 2024

The GEFS, ECENS, and CMCE are in good agreement on the 500-hPa longwave pattern
forecast that features a ridge over the North Pacific, a full-latitude trough
over western North America, and a subtropical ridge centered across the Gulf of
Mexico. Temperature tools are in excellent agreement for the lower 48 states,
due to the stable and amplified longwave pattern. The full-latitude trough with
negative 500-hPa height anomalies favor below-normal temperatures for nearly
all of the western CONUS. A strengthening subtropical ridge over the Gulf of
Mexico along with a predicted storm across the north-central CONUS favors
above-normal temperatures from the Great Plains to the East Coast.
Probabilities are slightly lower today across the Northeast as this region
could have a brief period of cold air advection at the beginning of week-2.

The amplified longwave trough along with good agreement among the reforecast
tools and uncalibrated output support an increased chance of above-normal
precipitation throughout the western CONUS, Great Plains, and Midwest. The
largest above-normal precipitation probabilities are forecast from the Four
Corners Region eastward to the Great Plains where model guidance is beginning
to converge on a low pressure track. Similar to the 6-10 day period, the drier
GEFS reforecast tool and NAEFS are preferred with a slight lean towards
below-normal precipitation across the Mid-Atlantic and Southeast. This is also
supported by the uncalibrated 7-day GEFS and ECENS which have less than 0.5
inch of precipitation.

For the second consecutive day, temperature tools offer conflicting signals
across western and northern Mainland Alaska. Therefore, the week-2 outlook
leaned towards the consolidation tool (skill-weighted combination of GEFS and
ECENS) with near normal temperature favored for a majority of Alaska. Elevated
above-normal temperature probabilities are forecast for the North Slope along
with the Aleutians and coastal southwestern Alaska. An upstream trough over the
Bering Sea and southwesterly flow favor above-normal precipitation throughout
Alaska. Early in week-2, a majority of ensemble members from the GEFS and ECENS
depict a strong low pressure system tracking from the Bering Sea to
southeastern Alaska.

Based on the GEFS and ECENS, increased chances of above-normal temperatures and
above-normal precipitation are forecast for Hawaii.

The official 8-14 day 500-hPa height blend consists of: 35% of Today`s 6z GFS
Ensemble Mean centered on Day 11, 35% 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: Above average, 4 out of 5, due to
a predicted amplified longwave pattern and good agreement among the temperature
and precipitation tools.

FORECASTER: Brad Pugh

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:
19531119 - 19611114 - 19611104 - 19561117 - 19711117


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:
19561117 - 19611104 - 19611114 - 19531119 - 19711116


6-10 DAY OUTLOOK TABLE
Outlook for Nov 13 - 17 2024

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



8-14 DAY OUTLOOK TABLE
Outlook for Nov 15 - 21 2024

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

                           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.

$$