Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Mon March 18 2024
6-10 DAY OUTLOOK FOR MAR 24 - 28 2024
Dynamical models are in good agreement today on the positioning of the mean
500-hPa height features during the 6-10 day period. There are two areas of
positive 500-hPa height anomalies, one centered east of the Canadian Maritimes
spreading into the northeastern contiguous U.S. (CONUS), and a second centered
over Alaska with positive heights spreading towards the North Pole and into the
central North Pacific. In southern Canada and the western half of the CONUS
negative 500-hPa height anomalies are forecast with a trough digging into the
central CONUS by the middle of the period.
Below-normal temperatures are favored across the western CONUS east to the
Upper-Mississippi Valley, Central Plains and parts of the Southern Plains along
and behind the mean 500-hPa trough axis. The strongest chances for below-normal
temperatures are forecast for the Northern Plains with chances exceeding 80%
across this region. Meanwhile, east of the Mississippi River and extending
along the Texas Gulf Coast, above-normal temperatures are forecast. There is
lower confidence in the above-normal as the mid-level trough shifts eastward
during the period and the raw dynamical tools are cooler relative to the
reforecast and short term bias-corrected tools. In Alaska, with strong positive
500-hPa height anomalies forecast during the period, above-normal temperatures
are strongly favored across most of the mainland, while in parts of Southeast
Alaska, near to slightly-below normal is favored. For Hawaii, near to slightly
below-normal temperatures are favored for the state.
Above-normal precipitation is favored across most of the country during the
6-10 day period. The highest chances for above-normal precipitation are
forecast in the southwestern CONUS and in the Mississippi Valley and Great
Lakes. In the southwestern CONUS, a deep trough will be moving through the
region early in the period bringing a period of unsettled weather to the area.
Additionally, the precipitation climatology for this region for late March is
relatively low, increasing chances for any precipitation to exceed normal. As
this trough progresses inland, lee-side cyclogenesis is forecast to develop and
will track into towards the Great Lakes and an associated frontal system may
extend towards the Gulf Coast. In Alaska, above-normal precipitation is
forecast across much of the Mainland with below-normal forecast in parts of
Southeast Alaska as the above-normal 500-hPa heights may displace the storm
track northwards. In Hawaii, near to below-normal precipitation is forecast.
The official 6-10 day 500-hPa height blend consists of 20% of Today's 0z GFS
Ensemble Mean centered on Day 8, 20% of Today's 6z GFS Ensemble Mean centered
on Day 8, 40% of Today's 0z European Ensemble Mean centered on Day 8, and 20%
of Today's 0z Canadian Ensemble Mean centered on Day 8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: About-average, 3 out of 5, due to
fair agreement among all the model tools for much of the country offset by the
very progressive nature of the pattern.
8-14 DAY OUTLOOK FOR MAR 26 - APR 01, 2024
The week-2 height forecast is less certain than the 6-10 day period. The
ensemble dynamical tool means are less amplified relative to the earlier period
with lesser agreement on the placement of the height anomalies. Generally, the
tools maintain an area of negative 500-hPa height anomalies over the CONUS with
positive 500-hPa height anomalies across much of Alaska and Canada. However,
the weekly means don’t tell the whole story due to the progressive nature of
the pattern during the period. At the onset of the period, deep mid-level low
pressure is forecast across the center of the CONUS with strong positive
mid-level anomalies forecast for the Northeast. The negative 500-hPa height
anomalies are forecast to progress eastward into the Great Lakes and weaken
while shifting the positive 500-hPa anomalies over the Northeast offshore.
Meanwhile, a second area of negative anomalies and associated troughing is
forecast to move inland from the eastern Pacific; however, at this time, this
trough is forecast to be less amplified relative to the trough early in the
period. In Alaska, positive 500-hPa height anomalies at the onset of the period
are likely to be displaced by negative 500-hPa height anomalies by the end of
week-2. In Hawaii, tools are generally mixed but lean towards positive 500-hPa
height anomalies during the period.
In week-2 as the mid-level trough progresses eastward, displacing the 500-hPa
height anomalies across the northeastern CONUS in the 6-10 day, below-normal
temperature chances extend eastward into the Ohio, Tennessee, Lower-Mississippi
Valley, and parts of the Southeast while maintaining coverage across the
western CONUS. Probabilities are slightly reduced across the Northern Plains
relative to the 6-10 day period but chances continue to exceed 60% for
below-normal temperatures across this region. In the Northeast, probabilities
exceed 50% for above-normal temperatures ahead of the trough. In Alaska, with
500-hPa height anomalies relaxing and forecast to turn negative by the end of
the period, the strong chances for above-normal temperatures forecast in the
6-10 day period are significantly reduced and focused in the southwestern
Mainland. Near- to below-normal temperatures are forecast for the North Slope,
eastern Mainland and Southeast Alaska. In Hawaii, below-normal temperatures are
slightly favored.
During week-2, above-normal precipitation remains most likely for much of the
country, although with weaker probabilities relative to the 6-10 day period, as
Pacific flow continues to bring moist air into the CONUS. In the southwestern
CONUS, slightly elevated chances of above-normal precipitation are forecast due
to continued unsettled weather and potential for a second area of troughing to
move onshore during the period. Meanwhile, in the East a baroclinic zone is
likely to become established as the trough progresses eastward. This slightly
enhances chances for above-normal precipitation across the East Coast. In parts
of the Northern and Southern Plains near to below-normal precipitation is
favored for areas displaced from the main storm track. In Alaska, above-normal
precipitation is slightly favored for central and southern Mainland Alaska
along with Southeast. As the strong ridging across the state breaks down it may
allow for more precipitation to work into southern Alaska. Near-normal
precipitation is favored for Hawaii consistent with the blend of tools and
consolidation tools.
The official 8-14 day 500-hPa height blend consists of: 20% of Today's 0z GFS
Ensemble Mean centered on Day 11, 20% of Today's 6z GFS Ensemble Mean centered
on Day 11, 40% of Today's 0z European Ensemble Mean centered on Day 11, and 20%
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 fair
agreement between the dynamical tools on the 500-hPa height pattern and in the
sensible weather tools offset by the continued progressive pattern
FORECASTER: Ryan Bolt
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
March 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:
20000331 - 19920311 - 19920330 - 19880312 - 19620330
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:
20000330 - 19920311 - 19920329 - 20050311 - 19880311
6-10 DAY OUTLOOK TABLE
Outlook for Mar 24 - 28 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 B A WYOMING B A
UTAH B A ARIZONA B A COLORADO B A
NEW MEXICO B A N DAKOTA B A S DAKOTA B A
NEBRASKA B A KANSAS B A OKLAHOMA B A
N TEXAS N A S TEXAS A A W TEXAS B A
MINNESOTA B A IOWA B A MISSOURI B A
ARKANSAS N A LOUISIANA A A WISCONSIN B A
ILLINOIS N 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 A
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE A A
AK ALEUTIAN A A AK WESTERN A A AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL A B
8-14 DAY OUTLOOK TABLE
Outlook for Mar 26 - Apr 01, 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 B A WYOMING B A
UTAH B A ARIZONA B A COLORADO B A
NEW MEXICO B A N DAKOTA B A S DAKOTA B A
NEBRASKA B A KANSAS B A OKLAHOMA B A
N TEXAS B N S TEXAS B B W TEXAS B N
MINNESOTA B A IOWA B A MISSOURI B A
ARKANSAS B A LOUISIANA B N WISCONSIN B A
ILLINOIS B A MISSISSIPPI B A MICHIGAN N A
INDIANA B A OHIO N A KENTUCKY B A
TENNESSEE B A ALABAMA B A NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA N A
MARYLAND A A DELAWARE A A VIRGINIA N A
N CAROLINA N A S CAROLINA N A GEORGIA N A
FL PNHDL N A FL PENIN N A AK N SLOPE N N
AK ALEUTIAN A N AK WESTERN A N AK INT BSN N N
AK S INT A A AK SO COAST A 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.
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