Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Mon May 16 2022
6-10 DAY OUTLOOK FOR MAY 22 - 26 2022
Today's model solutions are in fairly good agreement in predicting a 500-hPa
height pattern consistent with the positive phase of the Arctic Oscillation
(AO) early in the period. On day 6, below normal heights are forecast across
most of the higher latitudes of North America with troughs extending southward
to eastern Alaska and the north-central CONUS. Near to above normal heights are
forecast farther to the south across the southern CONUS, punctuated by a ridge
near California. As time progresses, the positive AO pattern is forecast to
weaken with heights returning to near normal across much of the higher
latitudes of North America. Corresponding to this forecast pattern transition
across higher latitudes, the flow pattern over the CONUS is generally predicted
to become more zonal by the end of the period. Farther to the north, troughing
is forecast to persist across much of Mainland Alaska for most of the period,
while ridging is predicted upstream over the Aleutians.
Cool, Canadian surface high pressure predicted early in the period favors below
normal temperatures for the Great Lakes as well as the Upper and Middle
Mississippi Valley. A weak tilt toward below normal temperatures extends
westward along the northern tier of the CONUS as dynamical model guidance
forecasts modest height falls for the northwestern CONUS by the end of the
period. Near to above normal temperatures are favored farther to the south,
across the southern tier of the CONUS, underneath predicted near to above
normal heights. Probabilities of near to above normal temperatures are also
enhanced across the Eastern Seaboard, ahead of a mean trough forecast over the
east-central CONUS. The highest probabilities of above normal temperatures
(exceeding 50 percent) are indicated for California, due to predicted ridging,
and for Florida, to the south of a frontal boundary forecast early in the
period. Conversely, cooler than normal temperatures are most likely for
northern and eastern Alaska due to persistent troughing while a slight tilt
toward above normal temperatures are indicated for southwestern Alaska due to
predicted upstream ridging.
An active pattern is favored for the Gulf and East coasts around the periphery
of a mean trough predicted over the east-central CONUS. The greatest likelihood
of above normal precipitation (greater than 50 percent) is indicated for the
central and eastern Gulf Coast region and parts of the Southeast, due to the
potential for enhanced moisture advection from the nearby Gulf and Atlantic
combined with a predicted stalled frontal boundary in the vicinity. Near to
below normal precipitation is most likely for most of the Northern and Central
Plains as well as for much of the Middle and Upper Mississippi Valley, due to
predicted surface high pressure early in the period. A tilt toward near to
below normal precipitation extends westward to much of the West Coast, due to
predicted ridging near California. Weak troughing leads to enhanced
probabilities of above normal precipitation farther to the north, across parts
of the Pacific Northwest, the Alaska Panhandle, and eastern portions of
Mainland Alaska. Ridging predicted over the Aleutians leads to a slight tilt
toward below normal precipitation for southwestern Alaska.
The official 6-10 day 500-hPa height blend consists of 30% of Today's 6z GFS
Ensemble Mean centered on Day 8, 5% of Today's operational 6z GFS centered on
Day 8, 30% of Today's 0z European Ensemble Mean centered on Day 8, 5% of
Today's operational 0z ECMWF 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: Average, 3 out of 5, due to fairly
good agreement on a positive AO pattern early in the period offset by a
transition to a less amplified pattern late.
8-14 DAY OUTLOOK FOR MAY 24 - 30 2022
During week-2, a transition to a low amplitude pattern is expected with only
modest 500-hPa height anomalies forecast over most of North America by the
middle of the period. Therefore, the mean 500-hPa pattern for the period as a
whole features weak anomalies across most of the forecast domain with a slight
tilt toward below normal heights forecast for parts of the northern tier of the
CONUS and near to slightly above normal heights forecast for most of the
southern tier. Height departures are generally larger across Alaska relative to
the CONUS as a trough is forecast to persist over the Mainland for most of the
period with upstream ridging continuing over the Aleutians
Low amplitude flow predicted across the CONUS is expected to lead to enhanced
north-south temperature gradients. Correspondingly, below normal temperatures
are slightly favored across most of the Northern Tier while above normal
temperatures are most likely for most of the southern third of the CONUS.
Increased chances of below normal temperatures are forecast across most of the
Alaska Mainland as well as the Panhandle due to persistent troughing.
The potential for a stalled frontal boundary combined with enhanced moisture
advection from the Gulf of Mexico and the Atlantic leads to elevated chances of
above normal precipitation for the Gulf Coast Region, Lower Mississippi Valley,
and much of the Southeast. Above normal precipitation is also favored for the
Northern Plains, Upper Mississippi Valley, the Great Lakes, and parts of the
Northeast, due to the likelihood of enhanced north-south temperature gradients
and associated frontal activity. A slight tilt toward above normal
precipitation is also indicated for parts of the Great Basin and the Central
Rockies due to potential trough development over the southwestern CONUS toward
the middle and end of the period. Persistent cyclonic flow leads to elevated
chances of above normal precipitation across eastern Alaska and parts of the
Pacific Northwest. Conversely, predicted ridges lead to increased chances of
below normal precipitation for much of California and parts of southwestern
Alaska.
The official 8-14 day 500-hPa height blend consists of: 25% of Today's 6z GFS
Ensemble Mean centered on Day 11, 5% of Today's operational 0z GFS 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: Below average, 2 out of 5, due to
predicted weak mean 500-hPa anomalies across most of the forecast domain.
FORECASTER: Scott H
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 May
19.
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:
20000508 - 19620501 - 20060530 - 19620530 - 19860513
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:
19620502 - 20000507 - 20060529 - 20010528 - 20080426
6-10 DAY OUTLOOK TABLE
Outlook for May 22 - 26 2022
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON N N NRN CALIF A B
SRN CALIF A B IDAHO N N NEVADA A B
W MONTANA B N E MONTANA B N WYOMING N N
UTAH A N ARIZONA A N COLORADO N N
NEW MEXICO A N N DAKOTA B N S DAKOTA B B
NEBRASKA N B KANSAS N B OKLAHOMA N N
N TEXAS N A S TEXAS A A W TEXAS N A
MINNESOTA B N IOWA B N MISSOURI B N
ARKANSAS N N LOUISIANA A A WISCONSIN B N
ILLINOIS B N MISSISSIPPI N A MICHIGAN B A
INDIANA B N OHIO B A KENTUCKY N N
TENNESSEE N N ALABAMA N A NEW YORK N A
VERMONT N A NEW HAMP A A MAINE A A
MASS A A CONN N A RHODE IS A A
PENN N A NEW JERSEY N A W VIRGINIA N A
MARYLAND N A DELAWARE N A VIRGINIA N A
N CAROLINA N A S CAROLINA N A GEORGIA N A
FL PNHDL A A FL PENIN A A AK N SLOPE B N
AK ALEUTIAN A B AK WESTERN N B AK INT BSN B A
AK S INT B A AK SO COAST A A AK PNHDL B A
8-14 DAY OUTLOOK TABLE
Outlook for May 24 - 30 2022
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B N OREGON B N NRN CALIF A B
SRN CALIF A B IDAHO B N NEVADA N N
W MONTANA B N E MONTANA B N WYOMING B A
UTAH N A ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA B A S DAKOTA N A
NEBRASKA N N KANSAS A N OKLAHOMA A N
N TEXAS A A S TEXAS A A W TEXAS A N
MINNESOTA B A IOWA N N MISSOURI N N
ARKANSAS A A LOUISIANA A A WISCONSIN B A
ILLINOIS N N MISSISSIPPI A A MICHIGAN B A
INDIANA N N OHIO B N KENTUCKY N N
TENNESSEE N N ALABAMA A A NEW YORK B A
VERMONT N A NEW HAMP N A MAINE N A
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 A
FL PNHDL A A FL PENIN A A AK N SLOPE B N
AK ALEUTIAN N B AK WESTERN B N AK INT BSN B A
AK S INT B N AK SO COAST B A AK PNHDL B 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.
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