485
FXUS06 KWBC 062002
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EST Wed November 06 2024

6-10 DAY OUTLOOK FOR NOV 12 - 16 2024

Model agreement improved today on the 500-hPa longwave pattern and the GEFS,
ECENS, and CMCE depict a ridge over the North Pacific, a trough of varying
amplitude near the West Coast, and a ridge over the eastern contiguous U.S.
(CONUS). The GEFS and the CMCE remain the most amplified with the 500-hPa
trough near the West Coast, but the ECENS has trended in that direction and
away from a mid-level ridge that its solution had yesterday. Given the better
continuity the past few days, the GEFS and CMCE are weighted most heavily in
the 500-hPa height blend.

From the Great Plains to the East Coast, predicted mean southerly flow during
this 5-day period favors above-normal temperatures. The largest probabilities
are forecast from the Mississippi River to the East Coast, where the GEFS and
ECENS have daily temperatures averaging 10 to 20 degrees F above normal on days
6 and 7. The 500-hPa trough with negative 500-hPa height departures favors
below-normal temperatures throughout most of the western CONUS. However, the
reforecast tools differ for this region with the GEFS (ECENS) featuring
increased below (above) normal temperature probabilities. Overall the GEFS
reforecast tool has higher skill recently according to the consolidation
weights and that model solution is preferred.

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 7 and 8. Increased above-normal precipitation
probabilities are forecast for much of the central and eastern CONUS, but
forecast confidence for above-normal precipitation is highest across the
Midwest. On day 6, an amplified 500-hPa trough is forecast to be located across
the Rockies and then another mid-level trough is forecast to quickly redevelop
over the western CONUS. This evolving longwave pattern along with good
agreement among the precipitation tools favor above-normal precipitation for a
majority of the western CONUS.

Surface high pressure to the north and east of Alaska and its associated
northeasterly surface flow lead to increased below-normal temperature
probabilities for eastern Mainland and southeastern Alaska. Westerly flow
slightly favors above-normal temperatures across the Aleutians and coastal
southwestern Alaska. A low pressure system is expected to emerge from the
Bering Sea later in the period which elevates above-normal precipitation
probabilities for a majority of 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, 30% of Today`s 0z European Ensemble Mean
centered on Day 8, and 35% of Today`s 0z Canadian Ensemble Mean centered on Day
8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Average, 3 out of 5, due to good
model agreement on the longwave pattern offset by differences in the reforecast
temperature tools across the western CONUS and continued uncertainty in the
precipitation outlook for the eastern CONUS.

8-14 DAY OUTLOOK FOR NOV 14 - 20 2024

The GEFS, ECENS, and CMCE are in good agreement as a high amplitude ridge with
large positive 500-hPa height anomalies becomes persistent over the North
Pacific. Downstream of this strengthening mid-level ridge across the North
Pacific, a trough-ridge longwave pattern is forecast to continue over the
CONUS. Due to the predicted storm track across the north-central CONUS,
positive 500-hPa height anomalies, and an absence of any strong cold air
advection, above-normal temperatures are favored from the Great Plains to the
East Coast. Similar to the 6-10 day outlook, the GEFS reforecast tool is
preferred across the western CONUS based on its higher skill recently. The
persistent longwave trough and associated negative 500-hPa height anomalies
support elevated below-normal temperature probabilities from the Continental
Divide westward to the West Coast.

On day 8, a low pressure system and a trailing cold front are forecast to cross
the eastern CONUS which favors near to above normal precipitation. However, the
outlook hedged on the drier side of model guidance based on the analog tool
derived from the manual 500-hPa height blend and teleconnections upon the
positive 500-hPa height anomaly centered over the North Pacific. Elsewhere,
across much of the central and western CONUS, the longwave trough and good
agreement among the reforecast tools and uncalibrated output support an
increased chance of above-normal precipitation. Later in week-2, the amplifying
trough over the western CONUS would favor surface low development across the
Central Rockies with a northeastward track to the Upper Mississippi Valley.

Temperature tools offered conflicting signals which are consistent with a
variable temperature pattern during this 7-day period. 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.

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, 30% of Today`s 0z European Ensemble Mean
centered on Day 11, and 35% of Today`s 0z Canadian Ensemble Mean centered on
Day 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Average, 3 out of 5, due to good
model agreement on the longwave pattern offset by differences in the reforecast
temperature tools across the western CONUS and continued uncertainty in the
precipitation outlook for the eastern CONUS.

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:
19561117 - 19531119 - 19611113 - 19611104 - 19711116


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 - 19711116 - 19611104 - 19531119 - 19571115


6-10 DAY OUTLOOK TABLE
Outlook for Nov 12 - 16 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    N     COLORADO    N    A
NEW MEXICO  N    N     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    N
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    N
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    N     DELAWARE    A    N     VIRGINIA    A    N
N CAROLINA  A    N     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  N    N
AK ALEUTIAN A    A     AK WESTERN  N    A     AK INT BSN  B    A
AK S INT    B    A     AK SO COAST B    A     AK PNHDL    B    N



8-14 DAY OUTLOOK TABLE
Outlook for Nov 14 - 20 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     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    A     KENTUCKY    A    A
TENNESSEE   A    A     ALABAMA     A    N     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    N     W VIRGINIA  A    A
MARYLAND    A    N     DELAWARE    A    N     VIRGINIA    A    N
N CAROLINA  A    N     S CAROLINA  A    N     GEORGIA     A    N
FL PNHDL    A    N     FL PENIN    A    N     AK N SLOPE  A    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.

$$