233
FXUS06 KWBC 211918
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Fri June 21 2024

6-10 DAY OUTLOOK FOR JUN 27 - JUL 01, 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 across the Northern Rockies and
Northern High Plains. Negative 500-hPa height anomalies are predicted over much
of Canada and parts of the interior northwestern CONUS. Weak positive 500-hPa
height anomalies are forecast across much of the remainder of the CONUS by all
of todays ensemble means. Over time, the height anomalies over the eastern
CONUS are forecast to gradually increase in amplitude, though this becomes more
apparent in week-2. Near to slightly above-normal 500-hPa heights 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
the Pacific Northwest, Northern Intermountain region, and along the Canadian
border into the northern Great Lakes region and Northeast. Above-normal
temperature chances exceed 60% from the southern High Plains eastward into
lower portions of the Mississippi Valley to Georgia and Florida. Below-normal
temperatures are favored from the Pacific Northwest and Northern Intermountain
region eastward across the extreme northern tier of states (very close to the
Canadian border), under a predicted trough that is forecast to shear out.
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 cool sea-surface
temperatures. For the Alaska Panhandle region, above-normal temperatures are
favored for the northern and central thirds of the area, with near-normal
temperatures favored over the southern third. 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.

A slight tilt towards above-normal precipitation is favored for approximately
half of the CONUS, with greater chances for above-normal precipitation depicted
for the far northern Plains/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 another tropical cyclone that is expected
to develop over the Bay of Campeche and follow a similar track to that of
former Tropical Storm Alberto. 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. Below-normal
precipitation is also favored over the vicinity of the Carolinas, based largely
on raw precipitation guidance from the ECENS and on increasing dryness in the
region due to high heat and increased evapotranspiration (ET). Conflicting
precipitation signals across much of the eastern CONUS warrants a broad area of
favored near-normal precipitation for that region. For most of Alaska,
differences among precipitation tools lead to near-normal precipitation being
favored, with relatively small areas of favored above-normal precipitation for
western and southwestern portions of the state, and below-normal precipitation
for most of Southeast Alaska, as depicted by the automated precipitation tool.
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 29 - JUL 05, 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
parts of the eastern CONUS. The manual height blend, which is almost equally
weighted between the three ensemble means, depicts at least +60 meter
departures over the vicinity of the Ohio Valley and Mid-Atlantic region. For
most of the remainder of the CONUS, positive mid-level height anomalies of +30
to +60 meters are depicted. In the full-height field, the manual height blend
depicts an area of +594 dm heights over the southern Rockies and adjacent
Plains. A trough is predicted to deamplify across the interior Northwest during
the period, with near to slightly above-normal heights depicted on the manual
height blend. Positive 500-hPa height anomalies of at least +30 meters are
predicted over Alaska in the manual blend, while modest negative height
anomalies are indicated over Hawaii.

Above-normal temperatures continue to be likely across most of the CONUS in
week-2 under positive 500-hPa height anomalies. Odds favoring above-normal
temperatures exceed 70% for parts of the southern Ohio and Tennessee Valleys.
For remaining areas of the CONUS (the Pacific Northwest and northern tier as
far east as the Upper Mississippi Valley), near to slightly below-normal
temperatures are favored under predicted troughing. Below-normal temperatures
are favored for the coastal areas of western Alaska, the Aleutians and the
islands in the Bering Sea, in large part due to the proximity of anomalously
cool sea-surface temperatures. Above-normal temperature chances are enhanced
across most 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. Near to slightly above-normal precipitation is favored
for most of the Lower 48 states, with at least a 40% chance for above-normal
precipitation depicted across the eastern Dakotas and Minnesota (due to
lingering troughing). Even greater odds for above-normal precipitation are
depicted across the Four Corners region, where the subtropical ridge is
forecast to be widespread and in a position that more closely resembles the
typical climatological monsoon configuration. With the anticipated weakening of
the Pacific Northwest trough, the area of below-normal precipitation favored in
the West during the earlier 6-10 day period is likely to expand in coverage.
Below-normal precipitation also continues to be favored in the vicinity of the
Carolinas and Georgia, as was noted in the earlier 6-10 day discussion. In
Alaska, large differences among the precipitation tools warrants near-normal
precipitation across nearly the entire state, with the exception of the western
Aleutians. 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:
20050626 - 19840610 - 20040607 - 19910626 - 19940615


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:
19840610 - 20050627 - 20050608 - 19940615 - 20040606


6-10 DAY OUTLOOK TABLE
Outlook for Jun 27 - Jul 01, 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       B    N     NEVADA      A    B
W MONTANA   B    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    N
N TEXAS     A    N     S TEXAS     A    A     W TEXAS     A    A
MINNESOTA   A    A     IOWA        A    A     MISSOURI    A    A
ARKANSAS    A    N     LOUISIANA   A    A     WISCONSIN   N    A
ILLINOIS    A    A     MISSISSIPPI A    N     MICHIGAN    A    A
INDIANA     A    N     OHIO        A    N     KENTUCKY    A    N
TENNESSEE   A    N     ALABAMA     A    N     NEW YORK    A    N
VERMONT     N    N     NEW HAMP    N    N     MAINE       N    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    B
N CAROLINA  A    B     S CAROLINA  A    B     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 A    N     AK PNHDL    A    N



8-14 DAY OUTLOOK TABLE
Outlook for Jun 29 - Jul 05, 2024

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  N    N     OREGON      A    B     NRN CALIF   A    B
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    B
W MONTANA   N    B     E MONTANA   N    N     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   N    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    N     KENTUCKY    A    N
TENNESSEE   A    N     ALABAMA     A    N     NEW YORK    A    N
VERMONT     A    A     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    B     S CAROLINA  A    B     GEORGIA     A    B
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 A    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.

$$