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FXUS06 KWBC 311918
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Wed May 31 2023
6-10 DAY OUTLOOK FOR JUN 06 - 10 2023
Today's model solutions are in good agreement on the predicted amplified
500-hPa circulation pattern across North America and surrounding regions during
the 6-10 day period. The manual 500-hPa height blend is based on the ensemble
means from the GFS, ECMWF, and Canadian model ensembles, though 0z
deterministic runs of the GFS and ECMWF models were also considered. The
resultant manual blend features anomalous mid-level troughing and associated
negative 500-hPa height anomalies over the Bering Sea and southwestern Alaska.
A trough and associated negative 500-hPa height anomalies continue to be
predicted over Southern California and much of the Southwest. An amplified
ridge and associated positive 500-hPa height anomalies are predicted from about
the Northern Great Plains northward and westward across the interior
northwestern CONUS, central and western Canada, and across Northern Alaska. The
expected phasing of mid-level troughs over much of the northeastern quarter of
the CONUS and over the Gulf of Mexico supports widespread coverage of negative
500-hPa height anomalies across these regions. Weak ridging in the full height
field is indicated over the Rio Grande Valley. The 0z GEFS and 0z deterministic
GFS model solutions differ somewhat from the overall model consensus by
predicting a slight westward shift of the northeastern CONUS trough, with the
deterministic run also depicting a substantial cutoff low centered over Ohio
and Indiana in the full height field. Accordingly, slightly more weight was
assigned to the ECMWF and Canadian ensemble mean runs in the manual 500-hPa
height blend.
Below normal temperatures are favored for southwestern Alaska (including the
Alaska Peninsula and Aleutians) in proximity to a mid-level trough during the
6-10 day period. Above normal temperatures are favored for much of the
remainder of Alaska, consistent with the consolidation of calibrated dynamical
model temperature forecasts, and proximity to a mid-level ridge and positive
500-hPa height anomalies. Above normal temperatures are likely across much of
the northern and east-central contiguous U.S. (CONUS) under the predicted
amplified ridge and primarily positive 500-hPa height anomalies. This area
extends from the Pacific Northwest eastward across the northern third of the
Great Basin, the Northern Rockies, the Northern Plains and eastern portions of
the Central Plains, the Middle and Upper Mississippi Valley, Ohio Valley, and
most of the Great Lakes region. Within this extensive area, probabilities of
above normal temperatures exceed 80 percent over the Columbia River Basin.
There is a tilt in the odds for above normal temperatures over southern
Florida, just ahead of a mean 500-hPa trough axis. Below normal temperatures
are favored from central and southern portions of California and southern
Nevada eastward across most of the Four Corners states, Central and Southern
Plains, and portions of the Lower Mississippi Valley, associated with a
mid-level trough and below normal 500-hPa heights. Recent temperature
observations favor near normal temperatures across the low-elevation deserts of
the Southwest. Below normal temperatures are favored from about the western
foothills of the Appalachians eastward to the Atlantic Coast from Maine to
North Carolina, consistent with the nearby mid-level trough. Similar to
yesterday, the GEFS bias-corrected and calibrated temperatures are cooler over
a much larger portion of the eastern CONUS than either the Canadian or European
ensemble mean bias-corrected and calibrated temperatures.
Above normal precipitation is favored over most of the western half of the
CONUS (except for western Washington where a slight tilt toward below normal
precipitation is indicated, and portions of the desert Southwest due to dry
climatology), and continuing eastward across the Lower Mississippi Valley. This
is associated with the upstream mid-level trough near the West Coast.
Probabilities favoring above normal precipitation exceed 70 percent for
northern portions of California and Nevada. Enhanced odds of below normal
precipitation are indicated over the eastern Dakotas, upper and middle portions
of the Mississippi Valley, the Great Lakes region, Ohio Valley, and the central
and northern Appalachians. This is based on increased subsidence of air between
an upstream ridge centered over the High Plains and a downstream trough
centered over the Atlantic Coast states. Mean surface low pressure and a
500-hPa trough over the Aleutians favor elevated probabilities of above normal
precipitation for western and southern portions of Alaska.
The official 6-10 day 500-hPa height blend consists of 30% of Today's 0z GFS
Ensemble Mean centered on Day 8, 35% 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: Above Average, 4 out of 5, due to
good model agreement among the 500-hPa height forecasts across the forecast
domain, offset by small differences among the surface temperature and
precipitation tools.
8-14 DAY OUTLOOK FOR JUN 08 - 14 2023
Ensemble mean solutions for the 8-14 day period predict a fairly persistent
500-hPa circulation pattern across North America and surrounding regions.
Mid-level troughs and modestly negative 500-hPa height anomalies are forecast
over the Bering Sea/southwestern Alaska, California and much of the Southwest,
and over eastern North America, with forecast 500-hPa height departures over
eastern North America being somewhat greater. A mid-level ridge and associated
positive 500-hPa height anomalies are depicted from central and western Canada
across Northern and Eastern Mainland Alaska. The 0z GEFS maintains a
well-defined trough centered near the Appalachians, while the 0z ECWMF and 0z
Canadian ensemble means depict poorly defined troughs centered on or just off
the East Coast.
Below normal temperatures are favored from California and Nevada eastward
across the Four Corners states and southern Wyoming into the Central and
Southern Plains, associated with a mid-level trough and accompanying near to
below normal 500-hPa heights. Probabilities for below normal temperatures
exceed 60 percent over portions of the Four Corners region. Recent temperature
observations tilt the odds towards near normal temperatures over the
low-elevation deserts of the Southwest. There are elevated odds of below normal
temperatures over the Northeast and Mid-Atlantic region, associated with the
mid-level trough and below normal 500-hPa heights predicted in that region.
Similar to yesterday, there are large differences between the cooler
bias-corrected and calibrated GEFS solutions over the east-central CONUS and
the warmer solutions depicted by the bias-corrected and calibrated Canadian and
European ensemble means. Below normal temperatures are also indicated over
southwestern portions of Alaska in proximity to a mid-level trough. Mid-level
ridging and associated positive 500-hPa height anomalies favor above normal
temperatures over much of the remainder of Alaska. Over the CONUS, above normal
temperatures are favored for the Pacific Northwest, Northern Great Basin,
Northern Rockies, Northern Plains, much of the Mississippi Valley, western
Great Lakes region, Lower Ohio and Tennessee Valleys, and from southern Texas
eastward across the Gulf Coast states and Southeast. This represents a
compromise between the competing bias-corrected and reforecast temperature
tools. Probabilities for above normal temperatures exceed 50 percent over
portions of the Pacific Northwest and Northern Intermountain region as well as
for southern Florida.
Above normal precipitation continues to be favored over most of the western
half of the CONUS, extending eastward across the southern half of the
Mississippi Valley, the southern Ohio Valley, Tennessee Valley, central and
southern portions of the Appalachians, and portions of the Southeast. This is
consistent with the consolidation of calibrated model precipitation forecasts
and the autoblend precipitation forecast. Below normal precipitation is favored
for portions of the Upper Mississippi Valley and adjacent eastern North Dakota,
and also over far southern New Mexico and southwestern Texas. Odds slightly
favor above normal precipitation over most of southern and western Alaska in
week 2, where various dynamical models overlap with the expected influence
region of the Aleutian 500-hPa trough.
The official 8-14 day 500-hPa height blend consists of: 30% of Today's 0z GFS
Ensemble Mean centered on Day 11, 35% 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: Near Average, 3 out of 5, due to
good model agreement on the 500-hPa height pattern across the forecast domain,
offset by the uncertainty in the surface temperature and precipitation patterns
over the east-central CONUS.
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
June 15.
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:
19890516 - 19960610 - 19620604 - 19560604 - 19990603
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:
19960611 - 19620604 - 19890516 - 19560603 - 19780527
6-10 DAY OUTLOOK TABLE
Outlook for Jun 06 - 10 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF B A IDAHO A A NEVADA N A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH B A ARIZONA B A COLORADO B A
NEW MEXICO B A N DAKOTA A N S DAKOTA A N
NEBRASKA N N KANSAS B A OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A B IOWA A B MISSOURI A N
ARKANSAS N N LOUISIANA B A WISCONSIN A B
ILLINOIS A B MISSISSIPPI N A MICHIGAN A B
INDIANA A B OHIO B B KENTUCKY B N
TENNESSEE B N ALABAMA N N NEW YORK B B
VERMONT B N NEW HAMP B N MAINE B N
MASS B N CONN B N RHODE IS B N
PENN B B NEW JERSEY B N W VIRGINIA B B
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B N S CAROLINA B N GEORGIA B N
FL PNHDL N N FL PENIN N N AK N SLOPE A B
AK ALEUTIAN B A AK WESTERN N A AK INT BSN A N
AK S INT N A AK SO COAST N A AK PNHDL A N
8-14 DAY OUTLOOK TABLE
Outlook for Jun 08 - 14 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF B A
SRN CALIF B A IDAHO A A NEVADA B A
W MONTANA A A E MONTANA A A WYOMING B A
UTAH B A ARIZONA B N COLORADO B A
NEW MEXICO B A N DAKOTA A N S DAKOTA N A
NEBRASKA B A KANSAS B A OKLAHOMA B A
N TEXAS N A S TEXAS A N W TEXAS N A
MINNESOTA A N IOWA A N MISSOURI N A
ARKANSAS N A LOUISIANA A A WISCONSIN A N
ILLINOIS A N MISSISSIPPI A N MICHIGAN A N
INDIANA A N OHIO N N KENTUCKY N A
TENNESSEE A A ALABAMA A N NEW YORK N N
VERMONT B N NEW HAMP N N MAINE B N
MASS N N CONN N N RHODE IS N N
PENN N N NEW JERSEY N N W VIRGINIA N N
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA N N S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A N AK N SLOPE A N
AK ALEUTIAN B N AK WESTERN N N AK INT BSN A N
AK S INT N N AK SO COAST N N AK PNHDL A 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.
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