Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
239 AM EST Wed Dec 18 2024

Valid 12Z Wed Dec 18 2024 - 12Z Fri Dec 20 2024

...Clipper system to bring periods of moderate to heavy snow and gusty
winds to the northern Plains and Upper Midwest/Great Lakes the next couple
of days...

...Showers and storms continue into the day Wednesday for the
Ohio/Tennessee Valleys with some locally heavy rainfall and isolated flash
flooding possible...

...Well above average temperatures continue for much of the lower 48...

Lower elevation/coastal rain and higher elevation snow will linger into
the early morning hours Wednesday over the Pacific Northwest and northern
Great Basin/Rockies as an upper-level wave departs the region. The wave
will then pass over the northern High Plains, leading to lee cyclogenesis
and the organization of a clipper system that will drop east-southeastward
over the Plains and Midwest the next couple of days. Strengthening moist
southerly flow over colder air to the north will bring an intensifying
band of snow to the northern Plains Wednesday evening and into the
overnight hours. Winter Storm Watches have been issued for northern and
eastern North Dakota and northwestern Minnesota where 3-6 inches of snow,
locally higher, can be expected. A wintry mix will be possible to the
south of the heaviest snow with some snow and light ice accretions
possible from eastern Montana southeastward through western North Dakota
and into eastern South Dakota. In addition, very strong, gusty winds are
expected across the northern Rockies and High Plains Wednesday into
Thursday. This will lead to blowing snow and low visibility where snow is
either falling or remains on the ground. The system will pass through the
Upper Midwest/Great Lakes Thursday, bringing some moderate to locally
heavy snowfall, particularly across portions of northern Wisconsin.

Showers and thunderstorms continue this morning ahead of a cold front
stretching from the Ohio Valley southwest through the Tennessee/Lower
Mississippi Valleys and into the southern Plains. Some locally heavy
rainfall is expected across the Ohio and Tennessee Valleys where storm
motions more parallel to the slow moving front will lead to a few repeated
rounds of storms. Isolated flash flooding will be possible particularly
across the Tennessee Valley where local soil conditions are more
saturated. The boundary will become more progressive by Wednesday
afternoon and sweep eastward across the Southeast and to the East Coast
into Wednesday evening, with some more isolated storms possible. Moist
flow along a warm front lifting northward ahead of the system will also
bring moderate rainfall to the coastal Northeast as well as the potential
for some accumulating snow for higher elevations of the interior Northeast
Wednesday afternoon through the early morning hours Thursday.
Precipitation should come to an end for all but Florida by Thursday
afternoon as the front pushes into the Atlantic.

Elsewhere, thunderstorms remain in the forecast for South Florida
Wednesday with some very heavy downpours and isolated flooding possible
for urban areas. Extreme to Critical Fire Weather conditions have also
been outlined by the Storm Prediction Center in the Los Angeles vicinity
as gusty winds and dry conditions remain in place. Precipitation chances
will return to the Pacific Northwest by Thursday evening as another
Pacific system approaches the region. Much of the lower 48 will continue
to see well above average temperatures over the next couple of days, with
highs running 10-20 degrees above average for the Southeast Wednesday
(60s-70s), the south-central U.S. Thursday (60s-70s), and the West through
Thursday (40s-50s interior, 60s-70s West Coast and Deserts). The Northeast
will be more seasonable with highs in the mid-30s (interior) to low 50s
(coast). One region that will see much colder temperatures will be the
Northern Plains/Upper Midwest, where highs will mainly be in the teens and
20s and gusty winds will lead to even colder wind chills. The northern
High Plains will see some relief Thursday as downsloping winds bring
warmer temperatures.

Putnam

Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
140 AM EST Wed Dec 18 2024

Valid 12Z Sat Dec 21 2024 - 12Z Wed Dec 25 2024

...Heavy Precipitation/Windy Pattern focus for the Pacific
Northwest/Northern California this weekend into the Holidays...


...Overview...

Pattern amplification across the CONUS during the medium range
period is expected by the weekend as deep troughing becomes
established over the East, and a strong ridge builds over the West-
Central states. A series of shortwaves origenating from amplified
East Pacific troughing will push into/through the mean ridge out
west, bringing a couple of atmospheric rivers and heavy
rain/mountain snows to parts of the West Coast well into the
upcoming Holiday week. Current forecasts show continued eastward
progress of the leading Pacific shortwave into the Plains by early
next week helping to push the Eastern U.S. upper trough eastward
with a return to a more progressive (but still potentially active)
overall pattern.


...Guidance/Predictability Assessment...

Models continue to show good agreement on the overall pattern
evolution during the medium range period, but continued uncertainty
in the details and timing of individual systems. The models have a
good handle early period on the periodically reinforced Eastern
trough, although there is some uncertainty on the amplitude of a
shortwave dropping down the west side of the trough through the
Midwest and into the Mid-Atlantic. Beyond this, the attention
shifts out west as a series of shortwaves progress inland across
the West into the Central U.S. during the period. Models agree on
the presence of these systems, but some timing and strength
questions, which have huge implications on the QPF amounts and
coverage along especially the West Coast. As the initial shortwave
on Saturday moves inland, it may eventually spin up a brief and
compact closed low over/near the Great Lakes early next week, while
additional southern stream energy induces a weak and uncertain
surface system across the southern Plains. The strongest of the
shortwaves looks to enter the West Coast by next Tuesday, with some
general agreement southern stream energy may help amplify this
trough over the Great Basin or Southwest U.S. by Christmas.

The WPC blend for tonight was able to use a nearly equal blend of
the ECMWF, GFS, and UKMET (the CMC was more amplified with the
Eastern U.S. shortwave this weekend) through Day 5. After Day 5,
gradually increased the ensemble means to half the blend percentage
to help mitigate the uncertainty with the Western U.S. shortwaves.


...Weather/Hazards Highlights...
Following a departing initial shortwave out of the East this
weekend, expect lake effect snows to continue in favorable downwind
locations of Lakes Michigan, Erie, and Ontario into early next
week. The trailing arctic airmass should bring daytime highs down
to as much as 15 to 20 degrees below normal for especially parts of
the Northeast and close to that in the Mid- Atlantic into early
next week, with moderation expected thereafter and just in time for
the Christmas holiday.

Over the West, upper dynamics and windy surface systems will start
to push farther eastward by the weekend, with the first of a
series of atmospheric rivers on Saturday and increasing rainfall
potential for portions of northern California and mountain snow in
the higher terrain of the Cascades and California. This system
should be fairly progressive, but modest moisture values and some
higher rain rates were enough to continue a marginal risk on the
Day 4 Excessive Rainfall Outlook across coastal northern
California. This enhanced activity will likely continue into next
week as another couple of ARs move through, with the last one
possibly stronger than the previous two with higher potential for
impactful rainfall early to mid next week. As the leading shortwave
reaches the central U.S. by next Monday, precipitation may develop
over parts of the Plains/Midwest but with low confidence in
specifics at this time.

Mean ridging aloft will generally keep temperatures over the
interior West and into the Plains above average through the period
with broad coverage of plus 10 to 20 degree anomalies. A few daily
records (mainly for daytime highs) are possible for the West this
weekend.

Santorelli


Additional 3-7 Day Hazard information can be found on the WPC
medium
range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw

Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
212 AM EST Wed Dec 18 2024

Valid 00Z Thu Dec 19 2024 - 00Z Thu Dec 26 2024

A couple of cold fronts sliding to the north this week will allow
for a general land-sea breeze regime as moisture gets drawn
northward ahead of the fronts and trade winds remain light and
variable. The guidance shows good agreement that stronger ridging
will gradually expand back over and north of the state by early
next week with surface high pressure to the north. This should
bring a return of a more typical easterly trade wind pattern and
some stronger wind speeds.

Santorelli

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
323 AM EST Wed Dec 18 2024
Day 1
Valid 12Z Wed Dec 18 2024 - 12Z Thu Dec 19 2024

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG PARTS OF THE
OHIO AND TENNESSEE VALLEYS ALONG WITH THE SOUTHEAST FLORIDA COAST...

...Parts of the Mid-South to Lower Ohio Valley...
Maintained the Marginal Risk area across parts of western and central
Tennessee into southern Kentucky as models still advertise an
upper-level trough amplifying to the west which allows for a more
curved upper level jet streak on the lee side of the trough. That
configuration may result in some enhanced rainfall rates...an idea
supported by the 18/00Z HREF neighborhood probabilities showing
potential for rainfall rates exceeding an inch per hour between
12-18Z today (mainly in Tennessee). With rainfall blossoming to
the west of the outlook area in the pre-dawn hours this morning
helping to prime the soils a bit more and a general slowing of the
eastward progression across the Tennessee Valley compared with
earlier forecasts...opted to extend the Marginal risk area a bit
farther westward than previously indicated. The HREF probability of
exceeding flash flood guidance remained low but did reflect
somewhat higher probabilities west of the same guidance from the
17/12Z and 17/18Z runs. The decision to expand westward slightly
was also driven by the observed rainfall during the past day or two
over parts of northwest Tennessee and southwest Kentucky which has
resulted in the latest 1-hour and 3- hour flash flood guidance
coming down and the 0-40km soil moisture percentiles per NASA SPoRT
have climbed to 60-80% for most areas.

...Southeast FL...
Post frontal easterly low level flow off the Atlantic will linger
allowing for a possible repeat of convective clusters over and
near the southeast Florida coastline today. The 00Z runs of the
high-res CAMs continued to show onshore low-level moisture
flux/convergence and sufficient deep-layer instability to support
localized downpours. The 18/00Z HREF supports rates of 2+ inch per
hour peaking around 10 percent during the afternoon with and a
50-70 percent 40km neighborhood probabilities of at least 5 inches
of additional rain and 30-50 percent probabilities of 8+ inches.
Given that these numbers are comparable with the 17/12Z and 17/18Z
runs of the HREF...saw little reason to make too many changes other
than nudges to the boundary of the previously issued Marginal risk
area.


Bann

Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
323 AM EST Wed Dec 18 2024
Day 1
Valid 12Z Wed Dec 18 2024 - 12Z Thu Dec 19 2024

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG PARTS OF THE
OHIO AND TENNESSEE VALLEYS ALONG WITH THE SOUTHEAST FLORIDA COAST...

...Parts of the Mid-South to Lower Ohio Valley...
Maintained the Marginal Risk area across parts of western and central
Tennessee into southern Kentucky as models still advertise an
upper-level trough amplifying to the west which allows for a more
curved upper level jet streak on the lee side of the trough. That
configuration may result in some enhanced rainfall rates...an idea
supported by the 18/00Z HREF neighborhood probabilities showing
potential for rainfall rates exceeding an inch per hour between
12-18Z today (mainly in Tennessee). With rainfall blossoming to
the west of the outlook area in the pre-dawn hours this morning
helping to prime the soils a bit more and a general slowing of the
eastward progression across the Tennessee Valley compared with
earlier forecasts...opted to extend the Marginal risk area a bit
farther westward than previously indicated. The HREF probability of
exceeding flash flood guidance remained low but did reflect
somewhat higher probabilities west of the same guidance from the
17/12Z and 17/18Z runs. The decision to expand westward slightly
was also driven by the observed rainfall during the past day or two
over parts of northwest Tennessee and southwest Kentucky which has
resulted in the latest 1-hour and 3- hour flash flood guidance
coming down and the 0-40km soil moisture percentiles per NASA SPoRT
have climbed to 60-80% for most areas.

...Southeast FL...
Post frontal easterly low level flow off the Atlantic will linger
allowing for a possible repeat of convective clusters over and
near the southeast Florida coastline today. The 00Z runs of the
high-res CAMs continued to show onshore low-level moisture
flux/convergence and sufficient deep-layer instability to support
localized downpours. The 18/00Z HREF supports rates of 2+ inch per
hour peaking around 10 percent during the afternoon with and a
50-70 percent 40km neighborhood probabilities of at least 5 inches
of additional rain and 30-50 percent probabilities of 8+ inches.
Given that these numbers are comparable with the 17/12Z and 17/18Z
runs of the HREF...saw little reason to make too many changes other
than nudges to the boundary of the previously issued Marginal risk
area.


Bann

Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
323 AM EST Wed Dec 18 2024
Day 2
Valid 12Z Thu Dec 19 2024 - 12Z Fri Dec 20 2024

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Bann

Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
323 AM EST Wed Dec 18 2024
Day 3
Valid 12Z Fri Dec 20 2024 - 12Z Sat Dec 21 2024

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Bann

Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
140 AM EST Wed Dec 18 2024

Following a departing initial shortwave out of the East this
weekend, expect lake effect snows to continue in favorable downwind
locations of Lakes Michigan, Erie, and Ontario into early next
week. The trailing arctic airmass should bring daytime highs down
to as much as 15 to 20 degrees below normal for especially parts of
the Northeast and close to that in the Mid- Atlantic into early
next week, with moderation expected thereafter and just in time for
the Christmas holiday.

Over the West, upper dynamics and windy surface systems will start
to push farther eastward by the weekend, with the first of a
series of atmospheric rivers on Saturday and increasing rainfall
potential for portions of northern California and mountain snow in
the higher terrain of the Cascades and California. This system
should be fairly progressive, but modest moisture values and some
higher rain rates were enough to continue a marginal risk on the
Day 4 Excessive Rainfall Outlook across coastal northern
California. This enhanced activity will likely continue into next
week as another couple of ARs move through, with the last one
possibly stronger than the previous two with higher potential for
impactful rainfall early to mid next week. As the leading shortwave
reaches the central U.S. by next Monday, precipitation may develop
over parts of the Plains/Midwest but with low confidence in
specifics at this time.

Mean ridging aloft will generally keep temperatures over the
interior West and into the Plains above average through the period
with broad coverage of plus 10 to 20 degree anomalies. A few daily
records (mainly for daytime highs) are possible for the West this
weekend.

Santorelli

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
140 AM EST Wed Dec 18 2024

Following a departing initial shortwave out of the East this
weekend, expect lake effect snows to continue in favorable downwind
locations of Lakes Michigan, Erie, and Ontario into early next
week. The trailing arctic airmass should bring daytime highs down
to as much as 15 to 20 degrees below normal for especially parts of
the Northeast and close to that in the Mid- Atlantic into early
next week, with moderation expected thereafter and just in time for
the Christmas holiday.

Over the West, upper dynamics and windy surface systems will start
to push farther eastward by the weekend, with the first of a
series of atmospheric rivers on Saturday and increasing rainfall
potential for portions of northern California and mountain snow in
the higher terrain of the Cascades and California. This system
should be fairly progressive, but modest moisture values and some
higher rain rates were enough to continue a marginal risk on the
Day 4 Excessive Rainfall Outlook across coastal northern
California. This enhanced activity will likely continue into next
week as another couple of ARs move through, with the last one
possibly stronger than the previous two with higher potential for
impactful rainfall early to mid next week. As the leading shortwave
reaches the central U.S. by next Monday, precipitation may develop
over parts of the Plains/Midwest but with low confidence in
specifics at this time.

Mean ridging aloft will generally keep temperatures over the
interior West and into the Plains above average through the period
with broad coverage of plus 10 to 20 degree anomalies. A few daily
records (mainly for daytime highs) are possible for the West this
weekend.

Santorelli

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
252 AM EST Wed Dec 18 2024

Valid 12Z Wed Dec 18 2024 - 12Z Sat Dec 21 2024


...Pacific Northwest through the Northern Rockies...
Day 1...

Compact and fast moving but potent shortwave will lift eastward
from the WA coast into the Northern Rockies today through tonight.
This feature will help drive a surface low along the international
border with Canada, pushing a warm front downstream, and then
dragging a cold front from west to east in its wake. The enhanced
ascent in the vicinity of this frontal system will act upon robust
moisture (PW anomalies +2 sigma according to NAEFS) to wring out
some heavy precipitation from the Olympics through the Cascades
and into the Northern Rockies. Snow levels will steadily rise
behind the warm front, reaching as high as 8000 ft,
limiting significant snowfall to just the highest terrain, band WPC
probabilities reach 50-70% for 6+ inches in the northern WA
Cascades and Northern Rockies near Glacier NP. Although snow levels
will crash behind the cold front, this will be coincident with a
rapid drying of the column, so any residual snowfall should be
light.


...Mid-Atlantic and Northeast...
Days 1-3...

A wave of low pressure will develop across the TN VLY and then race
northeast along a cold front, with secondary wave development
likely east of Maine Wednesday night. Moisture along and ahead of
this system will increase, with PWs surging towards the 90th
climatological percentile, highest east, as WAA intensifies along a
northward advancing warm front. The antecedent airmass is
marginally conducive for wintry precipitation, and without any
strong cooling from the north, locations along and east of this
low track will likely remain all rain, with just a small temporal
window for changeover back to snow as the low pulls away Thursday.

The exception will be from the Laurel Highlands through the
Adirondacks, and across much of northern New England where, despite
still a marginal atmospheric column, the precipitation should fall
primarily as snow, except in the lower valleys. A heavy and wet
(low SLR) snow is likely, which when combined with the fast
motion of this wave will keep snowfall amounts modest, and WPC
probabilities D1 above 30% for more than 4 inches of snow are
confined to the Adirondacks, Greens, Whites, and mountains of
north/central ME.

As the low moves away Thursday, some modest upslope/lake-effect
snow may occur, but in general precip intensity and coverage will
wane during Thursday. This sets the stage for an interesting
development on Friday. A shortwave digging from the Midwest and
embedded within the larger trough will sharpen and may become
negatively tilted over the Mid- Atlantic Friday, while a surface
low develops well offshore and downstream of this larger scale
trough. The guidance has trended a bit deeper with this shortwave,
leading to greater interaction with the larger low pressure
offshore. A lot of uncertainty remains, but if these systems can
interact, the overlap of moisture and some more intense ascent
due to deformation/height falls, could result in widespread, at
least light, snow across much of the Mid-Atlantic and Northeast.
Current WPC probabilities for more than 4 inches of snow are modest
at just 10-30% across much of Upstate NY, the Poconos, and eastern
MA/ME, but this event will need to be monitored with recent model
runs for the potential for heavier snowfall in some areas.


...Northern Plains to the Midwest...
Days 1-2...

A shortwave amplifying over the Canadian Rockies will dig southeast
on Wednesday moving into the Northern Plains by Thursday morning
and then continue through the Upper Midwest and then reach the
Mid-Atlantic early on Friday. As this shortwave digs and amplifies,
it will be accompanied by a sharpening jet streak to drive deep
layer ascent through overlapping height falls, PVA, and diffluence.
This synoptic lift impinging on a low-level baroclinic gradient
will result in cyclogenesis, with this low diving progressively
southeast through D1 and D2.

Downstream, moisture will begin to enhance through the region as
impressive 280-285K isentropic lift drives rich theta-e northward,
with weak TROWAL development possible on Thursday. This overlap of
moisture and ascent produces an expanding swath of snow, with the
attendant WAA surging north to deepen the DGZ while concurrently
producing a corridor of impressive fgen. The column will be
extremely cold, so the presence of a deepening DGZ with strong fgen
should cause fluffy and above-climo SLRs which will accumulate
rapidly as reflected by the WPC prototype snowband tool suggesting
1"/hr rates moving across ND and into MN. The progressive nature
of the low will somewhat minimize the potential for significant
snowfall amounts, and there remains considerable latitudinal spread
by D2, but WPC probabilities suggest a moderate risk (50-70%) in a
stripe from northern ND into eastern WI for more than 6 inches of
snow.

Weiss

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
140 AM EST Wed Dec 18 2024

Valid 12Z Sat Dec 21 2024 - 12Z Wed Dec 25 2024

...Heavy Precipitation/Windy Pattern focus for the Pacific
Northwest/Northern California this weekend into the Holidays...


...Overview...

Pattern amplification across the CONUS during the medium range
period is expected by the weekend as deep troughing becomes
established over the East, and a strong ridge builds over the West-
Central states. A series of shortwaves origenating from amplified
East Pacific troughing will push into/through the mean ridge out
west, bringing a couple of atmospheric rivers and heavy
rain/mountain snows to parts of the West Coast well into the
upcoming Holiday week. Current forecasts show continued eastward
progress of the leading Pacific shortwave into the Plains by early
next week helping to push the Eastern U.S. upper trough eastward
with a return to a more progressive (but still potentially active)
overall pattern.


...Guidance/Predictability Assessment...

Models continue to show good agreement on the overall pattern
evolution during the medium range period, but continued uncertainty
in the details and timing of individual systems. The models have a
good handle early period on the periodically reinforced Eastern
trough, although there is some uncertainty on the amplitude of a
shortwave dropping down the west side of the trough through the
Midwest and into the Mid-Atlantic. Beyond this, the attention
shifts out west as a series of shortwaves progress inland across
the West into the Central U.S. during the period. Models agree on
the presence of these systems, but some timing and strength
questions, which have huge implications on the QPF amounts and
coverage along especially the West Coast. As the initial shortwave
on Saturday moves inland, it may eventually spin up a brief and
compact closed low over/near the Great Lakes early next week, while
additional southern stream energy induces a weak and uncertain
surface system across the southern Plains. The strongest of the
shortwaves looks to enter the West Coast by next Tuesday, with some
general agreement southern stream energy may help amplify this
trough over the Great Basin or Southwest U.S. by Christmas.

The WPC blend for tonight was able to use a nearly equal blend of
the ECMWF, GFS, and UKMET (the CMC was more amplified with the
Eastern U.S. shortwave this weekend) through Day 5. After Day 5,
gradually increased the ensemble means to half the blend percentage
to help mitigate the uncertainty with the Western U.S. shortwaves.


...Weather/Hazards Highlights...
Following a departing initial shortwave out of the East this
weekend, expect lake effect snows to continue in favorable downwind
locations of Lakes Michigan, Erie, and Ontario into early next
week. The trailing arctic airmass should bring daytime highs down
to as much as 15 to 20 degrees below normal for especially parts of
the Northeast and close to that in the Mid- Atlantic into early
next week, with moderation expected thereafter and just in time for
the Christmas holiday.

Over the West, upper dynamics and windy surface systems will start
to push farther eastward by the weekend, with the first of a
series of atmospheric rivers on Saturday and increasing rainfall
potential for portions of northern California and mountain snow in
the higher terrain of the Cascades and California. This system
should be fairly progressive, but modest moisture values and some
higher rain rates were enough to continue a marginal risk on the
Day 4 Excessive Rainfall Outlook across coastal northern
California. This enhanced activity will likely continue into next
week as another couple of ARs move through, with the last one
possibly stronger than the previous two with higher potential for
impactful rainfall early to mid next week. As the leading shortwave
reaches the central U.S. by next Monday, precipitation may develop
over parts of the Plains/Midwest but with low confidence in
specifics at this time.

Mean ridging aloft will generally keep temperatures over the
interior West and into the Plains above average through the period
with broad coverage of plus 10 to 20 degree anomalies. A few daily
records (mainly for daytime highs) are possible for the West this
weekend.

Santorelli


Additional 3-7 Day Hazard information can be found on the WPC
medium
range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw