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6-10 Day outlooks are issued daily between 3pm & 4pm Eastern Time. All forecasts issued on weekends are completely automated while all weekday outlooks are modified by the forecaster. Please refer to the U.S. Prognostic Discussion for an explanation of terms and symbols used on these maps.
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Valid: May 13 - 17, 2025 (6-10 Day Outlook) Valid: May 15 - 21, 2025 (8-14 Day Outlook) Issued: May 07, 2025 |
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Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Wed May 07 2025
6-10 DAY OUTLOOK FOR MAY 13 - 17 2025
Today's ensemble mean solutions are in good agreement in depicting a high
amplitude 500-hPa pattern across much of North America. The period begins with
anomalous troughing over the Davis Strait extending southward to offshore of
Atlantic Canada. A strong anomalous ridge is forecast across the Great Lakes
and a trough or closed low is predicted to undercut this ridge over the
Southeast. Across western North America and the Eastern Pacific, three main
features are forecast to dominate, the first two features being a pair of
troughs located over the eastern Bering Sea and near or just inland of the west
coast of the Contiguous United States (CONUS). Ridging is forecast in between
these two troughs well offshore of the Pacific Northwest. The pattern for
Alaska is forecast to be slow-moving such that by the end of the period, the
trough over the Bering Sea is predicted to essentially remain in place. The
downstream trough near the West Coast is forecast to move across the Interior
West and eventually to the Northern Plains by day 10. The anomalous ridge over
the Great Lakes is forecast to drift eastward and slowly weaken. Finally, the
trough or closed low over the Southeast is predicted to slowly lift
northeastward to the Mid-Atlantic then move offshore by the middle or end of
the period.
Above normal temperatures are likely for most of the CONUS east of the Rockies
due to a combination of anomalous ridging over the Great Lakes and southerly
flow across the Plains and Mississippi Valley. The highest likelihood of
unseasonable warmth is across the central and eastern Great Lakes, near the
center of the predicted mean ridge. However, near normal temperatures are more
likely for the coastal Southeast and southern Mid-Atlantic as a predicted storm
system significantly reduces chances of anomalous warmth. Below normal
temperatures are likely for the western CONUS as a strong trough is forecast to
progress eastward across the region during the period. A slight tilt toward
above normal temperatures is indicated for southwestern Alaska ahead of the
Bering Sea trough. Above normal sea surface temperatures (SSTs) in nearby
waters may also contribute to increasing chances of above normal temperatures
for this region. Below normal temperatures are slightly favored for parts of
eastern Mainland Alaska consistent with predicted below normal heights and for
Southeast Alaska underneath anomalous northerly mid-level flow. Near normal
temperatures are favored for the remainder of the state due to weak or
conflicting guidance. Above normal temperatures are likely across Hawaii
consistent with anticipated above normal sea surface temperatures (SSTs) in
adjacent waters.
An active period is anticipated across much of the western CONUS as an
anomalous trough pushes inland from the Pacific during the period. As the
trough progresses eastward, enhanced above normal precipitation probabilities
are forecast across much of the West and eventually farther to the east across
the Northern and Central Plains and Upper and Middle Mississippi Valley as
southerly flow increases. Above normal precipitation is also likely for the
coastal Southeast and Mid-Atlantic as a slow moving low pressure system is
expected to promote ample moisture advection into this region from the Gulf and
Atlantic. In between these two active regions, near to below normal
precipitation is more likely across parts of the Southern Plains, the Lower
Mississippi Valley, the Ohio Valley, the central and eastern Great Lakes, and
much of the Northeast. Conversely, above normal precipitation is favored across
most of southern and central Alaska due to persistent anomalous troughing
predicted over the Bering Sea. Above normal precipitation is also favored for
Hawaii, consistent with skill weighted calibrated precipitation amounts
calculated from the GEFS and ECMWF ensembles.
The official 6-10 day 500-hPa height blend consists of 20% of Today's 6z GFS
Ensemble Mean centered on Day 8, 50% of Today's 0z European Ensemble Mean
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: Above average, 4 out of 5, due to
good agreement among today’s ensemble means.
8-14 DAY OUTLOOK FOR MAY 15 - 21 2025
The week-2 period begins with a highly amplified pattern featuring anomalous
ridging over the Great Lakes and troughs near the East Coast, the interior
West, the Northern Plains, and eastern Bering Sea. The trough over the Bering
Sea is forecast to gradually reduce in intensity. The trough over the Northern
Plains is forecast to progress eastward and weaken with time. The trough over
the Interior West is also forecast to weaken significantly with models
indicating a potential retrogression back toward the West Coast near the end of
the period. The ridge over the Great Lakes is generally forecast to lift
northeastward with heights returning to near normal in its wake across much of
the East during the latter half of the period. Farther to the west, increased
ridging is predicted across the Southern High Plains by the end of the period.
Generally near normal 500-hPa heights are forecast for Hawaii, well to the
south of a mean ridge forecast across the eastern Pacific.
Above normal temperatures are favored for most of the CONUS east of the
Mississippi and for much of the Southern Plains. This is especially true for
the eastern Gulf Coast Region northeastward to the eastern Great Lakes due to a
combination of anomalous ridging and southerly flow. However, relatively
modestly enhanced probabilities of above normal temperatures are indicated for
the Northeast and Mid-Atlantic coast as confidence is tempered in the wake of a
departing low pressure system early in the period. Cooler than normal
temperatures are favored for most of the western third of the CONUS due to
strong troughing, particularly early in the period. However, near normal
temperatures are more likely for much of northern and central California and
adjacent southwestern Oregon as 500-hPa heights are forecast to moderate by the
middle of the period. Near normal temperatures are also favored for most of
Alaska due to weak or conflicting guidance. However a slight tilt toward below
normal temperatures are indicated for a small portion of northeastern Alaska
associated with nearby Arctic surface high pressure to the north. Above normal
temperatures remain likely across Hawaii associated with anticipated above
normal SSTs in adjacent waters.
An active pattern is anticipated to continue into week-2 for much of the
Interior West (with the exception of climatologically dry areas of the
Southwest) due to a predicted trough early in the period. Farther to the east,
an active pattern is favored for much of the north-central CONUS as surface low
pressure is forecast to be well established by the beginning of the period. As
this surface low progresses northeast, increased southerly flow promotes
increased chances of above normal precipitation southward to the central Plains
and northern portions of the southern Plains and eastward to the northern
two-thirds of the Mississippi Valley. Below normal precipitation is more likely
across the Southeast as surface high pressure develops behind a departing low
off the coast. An active pattern and increased above normal precipitation
chances remain forecast for much of southern and central Alaska due to
persistent troughing over the Bering Sea. Above normal precipitation is also
favored for Hawaii, consistent with skill weighted calibrated precipitation
amounts calculated from the GEFS and ECMWF ensembles.
The official 8-14 day 500-hPa height blend consists of: 20% of Today's 6z GFS
Ensemble Mean centered on Day 11, 50% 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 a
predicted amplified pattern early in period offset by a potential moderation of
the pattern and increased uncertainty later in week-2.
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
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:
19880521 - 19570428 - 19870421 - 19780516 - 19700503
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:
19780516 - 19870421 - 19700502 - 20060426 - 19570427
6-10 DAY OUTLOOK TABLE
Outlook for May 13 - 17 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF B N IDAHO B A NEVADA B A
W MONTANA B A E MONTANA N A WYOMING B A
UTAH B A ARIZONA B N COLORADO B A
NEW MEXICO B N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A B W TEXAS A N
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A B WISCONSIN A A
ILLINOIS A N MISSISSIPPI A B MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A N ALABAMA A B 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 A NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA N A GEORGIA N A
FL PNHDL N N FL PENIN N A AK N SLOPE N N
AK ALEUTIAN A A AK WESTERN N A AK INT BSN N A
AK S INT N A AK SO COAST N A AK PNHDL B A
8-14 DAY OUTLOOK TABLE
Outlook for May 15 - 21 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B N OREGON B N NRN CALIF N N
SRN CALIF B N IDAHO B A NEVADA B N
W MONTANA B A E MONTANA B A WYOMING B A
UTAH B A ARIZONA B N COLORADO B A
NEW MEXICO B N N DAKOTA N A S DAKOTA N A
NEBRASKA N A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA N A IOWA A A MISSOURI A A
ARKANSAS A A 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 B 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 B S CAROLINA A B GEORGIA A B
FL PNHDL A B FL PENIN A B AK N SLOPE N N
AK ALEUTIAN N A AK WESTERN N A AK INT BSN N A
AK S INT N A AK SO COAST N 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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500mb Heights and Anomalies,
Time Series of Surface Forecast Skill,
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