871
FXUS06 KWBC 201920
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Thu June 20 2024

6-10 DAY OUTLOOK FOR JUN 26 - 30 2024

During the 6-10 day outlook period, a low-amplitude flow pattern continues to
be predicted over the Contiguous U.S. (CONUS) by the GEFS, ECMWF and Canadian
ensemble means, with a short wave trough moving inland over the Pacific
Northwest. Negative 500-hPa height anomalies are predicted over much of Canada
and parts of the northern tier of the western and central CONUS. Positive
500-hPa height anomalies are forecast across most of the remainder of the CONUS
by all of todays ensemble means, with +30 to +60 meter departures depicted on
the manual height blend. Over time, the height anomalies over the eastern CONUS
are forecast to gradually increase in amplitude, though this becomes more
apparent in week-2. Weak 500-hPa height anomalies are predicted over Alaska in
the manual blend, while modest negative height anomalies are indicated over
Hawaii.

Positive 500-hPa height anomalies and low-amplitude flow lead to likely
above-normal temperatures in the forecast across most of the CONUS, except for
parts of the Pacific Northwest and along the Canadian border into the central
CONUS. Above-normal temperature chances exceed 60% from the Four Corners region
eastward across the southern states to the Southeast Coast. Below-normal
temperatures are favored for parts of the Pacific Northwest, under a predicted
trough. Below-normal temperatures are favored for the Aleutians and islands in
the Bering Sea, and the immediate west coast of Alaska, supported by most
dynamical model forecasts and the proximity of unseasonably cold sea-surface
temperatures. Near-normal temperatures are favored for the Alaska Panhandle,
with a mid-level trough forecast to move across the region early in the 6-10
day period, followed by a mid-level ridge later in the period. Above-normal
temperatures are favored over most of interior Mainland Alaska, supported by
most of the temperature guidance. For Hawaii, the ERF CON tool favors
below-normal temperatures.

Above-normal precipitation is favored for the Alaska Peninsula and southwestern
Mainland Alaska, in advance of a mid-level trough predicted over the Bering
Sea. Near to below-normal precipitation chances are favored for Southeast
Alaska, where a transition from mid-level troughing to mid-level ridging is
expected. A slight tilt towards above-normal precipitation is favored for much
of the CONUS, with greater chances for above-normal precipitation depicted for
the Upper Midwest, the Pacific Northwest, and the Four Corners region. This is
based on expected shortwaves riding up and over the anomalous ridge predicted
over the east-central CONUS, a mid-level trough, and significant moisture
associated with the climatological onset of the Southwest Monsoon possibly
enhanced by another tropical system, respectively. Near to below-normal
precipitation is favored over northern and central portions of California and
Nevada, generally consistent with reforecast precipitation from the three
ensemble mean models. Conflicting precipitation signals across much of the
eastern CONUS warrants a broad area of favored near-normal precipitation for
that region. For Hawaii, the ERF CON and automated precipitation tools favor
increased odds of above-normal precipitation during the 6-10 day period.

The official 6-10 day 500-hPa height blend consists of 33% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 34% of Today`s 0z European Ensemble Mean
centered on Day 8, and 33% 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 agreement among the 500-hPa height forecasts and surface temperature
tools, offset by fairly weak precipitation signals for most of the country.

8-14 DAY OUTLOOK FOR JUN 28 - JUL 04, 2024

Generally, a zonal mid-level flow pattern is forecast over the CONUS in week-2,
with an increase in the amplitude of positive 500-hPa height anomalies over the
northeastern CONUS. A trough is predicted to deamplify across the Pacific
Northwest and Northern Rockies during the period, with slightly positive height
anomalies depicted on the manual height blend. Towards the end of week-2, daily
height anomaly forecasts from the various dynamical models indicate a very
broad area of significant positive height anomalies across most of the central
and southern CONUS. Weak 500-hPa height anomalies are predicted over Alaska,
while weak negative height anomalies continue to be forecast for Hawaii.

Above-normal temperatures continue to be likely across most of the CONUS in
week-2 (except for parts of the Pacific Northwest and northern tier as far east
as the Upper Mississippi Valley), under positive 500-hPa height anomalies.
Below-normal temperatures are favored for parts of the Pacific Northwest, under
a predicted trough. Below-normal temperatures are favored for the coastal areas
of western Alaska, the Alaska Peninsula, Kodiak Island, the Aleutians and
offshore islands, in large part due to the proximity of anomalously cold
sea-surface temperatures and the anticipated passage of shortwave energy across
that region. Near-normal temperatures are again favored for the Alaska
Panhandle, due to discrepancies between the warmer reforecast temperature tools
and the cooler bias-corrected and raw temperature tools. Above-normal
temperature chances are enhanced across much of Mainland Alaska, consistent
with reforecast temperature tools and the automated temperature forecast. The
ERF-CON and automated temperature tools for Hawaii continue to favor
below-normal temperatures during week-2.

The week-2 precipitation outlook is similar to the earlier 6-10 day
precipitation outlook. A slight tilt in the odds for above-normal precipitation
is indicated over approximately half of the Lower 48 states, with greater
chances favored across the Four Corners region and Upper Midwest, as noted in
the 6-10 day discussion.  The odds for above-normal precipitation across the
Pacific Northwest have diminished slightly relative to the 6-10 day period, due
to an anticipated weakening of the mid-level trough in that region. As a
result, the area of favored near to below-normal precipitation across parts of
the West has increased in coverage compared to the earlier 6-10 day period.
Near to slightly above-normal precipitation is depicted for Alaska,
underscoring significant differences among the various precipitation inputs.
The dynamical model-based precipitation tools continue to favor above-normal
precipitation chances across the Hawaiian Islands.

The official 8-14 day 500-hPa height blend consists of: 35% of Today`s 0z 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: Average, 3 out of 5, due to good
agreement among the temperature tools offset by weak and conflicting
precipitation signals for large portions of the country.

FORECASTER: Anthony A

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
July 18.


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:
19840609 - 19940615 - 19570616 - 19590627 - 20050626


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:
19840609 - 19940615 - 20050609 - 19570616 - 20050627


6-10 DAY OUTLOOK TABLE
Outlook for Jun 26 - 30 2024

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



8-14 DAY OUTLOOK TABLE
Outlook for Jun 28 - Jul 04, 2024

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

$$