Weather Prediction Center

National Oceanic and Atmospheric Administration

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 PM EDT Mon Mar 24 2025

Valid 00Z Tue Mar 25 2025 - 00Z Thu Mar 27 2025

...Significantly above average, warm to hot early Spring temperatures will
expand over the western/central U.S. this week with numerous monthly
record highs possible...

...Wet weather across northwestern Washington state today is expected to
taper off on Tuesday as chances for significant precipitation remain low
across the lower 48 the next couple of days...

A strong upper-level ridge building over the western into central U.S.
will bring an early Spring heat wave this week as significantly above
average temperatures expand in coverage across the region. Already well
above average temperatures on Monday will be even warmer on Tuesday, with
highs generally in the 60s and 70s for the Pacific Northwest/West Coast,
throughout the Intermountain West, and into the northern/central Plains.
Highs across the southern Plains will be in the 80s to low 90s while the
Desert Southwest will see highs soar into the 90s and may even reach 100.
Precipiation chances along the West Coast and into the southern Plains
will bring temperatures down a few degrees on Wednesday as the focus of
well above average highs shifts over the Intermountain West and
northern/central Plains. Numerous record-tying/breaking daily and monthly
highs will be possible Tuesday from Texas west through the Desert
Southwest and northward along the West Coast. Additional
record-tying/breaking highs will be possible in the Desert Southwest and
throughout the Intermountain West Wednesday.

Much of the country will be rather quiet with regards to significant
precipitation the next couple of days, especially after Monday evening. A
low pressure/frontal system approaching the East Coast will continue to
bring some showers and thunderstorms to the East Coast and Gulf Coast
through this evening, with some additional light snowfall accumulations
further north over portions of Maine into Tuesday morning. Lingering light
rain/snow showers will remain possible over the Great Lakes and interior
Northeast as the parent upper-low spins down. Heavy rainfall and a flood
risk will also wind down along upslope portions of the Olympic Mountains
and northern Cascades in Washington into Monday evening as an Atmospheric
River event comes to an end. Some lower elevation rain showers and higher
elevation snow showers will continue across the Pacific Northwest into the
northern Rockies as a frontal boundary lingers in the region. A clipper
system dropping southeastward through the Midwest into the Ohio Valley and
eastward into the Mid-Atlantic will also bring some light shower chances
the next couple of days, which may mix with a little snow for the Upper
Midwest and higher elevations of the Appalachians. A cluster of shower and
thunderstorms are expected Tuesday night along and north of a frontal
boundary through the Southern Plains, most likely over northern Texas and
southern Oklahoma. Finally, heading into Wednesday, increasing moisture
along the Rio Grande will bring shower and thunderstorm chances into
southern and southwestern Texas, and the next Pacific system approaching
the Pacific Northwest will also bring the return of wet weather to the
region.

Putnam


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

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
305 PM EDT Mon Mar 24 2025

Valid 12Z Thu Mar 27 2025 - 12Z Mon Mar 31 2025

19Z Update: The 12Z model guidance suite maintains good synoptic
scale agreement across the Continental U.S. for the end of the work
week. For the storm system developing across the Plains and Upper
Midwest this weekend, the UKMET is a bit more to the northwest of
the model consensus with the front placement, but not a major
outlier. More substantial diffences become apparent with the next
Pacific storm system, with the GFS taking the main low center well
to the north of the CMC and GFS, and lingering model spread in the
wake of that system. For the East Coast, the GFS is faster with the
front exiting the coast Monday night.

Taking these factors into account, Thursday and Friday incorporated
a general deterministic model blend, and then the ensemble means
were gradually increased to about 40% by early next week. The
previous forecast discussion is appended below for reference.
/Hamrick
-------------------

...Overview...

Most guidance shows a reloading mean trough over the eastern
Pacific with a strong system affecting the Pacific Northwest
Thursday into Friday with potential for another meaningful system
to affect the West Coast by Sunday-Monday. The downstream pattern
looks moderately progressive, with a very warm Rockies/Plains ridge
eventually moving off the East Coast while trailing shortwave
energy supports low pressure that should track northeastward from
the Plains during the weekend into early next week. The eastern
Pacific systems will bring areas of enhanced precipitation to the
West Coast while the system affecting the central/eastern U.S. by
Saturday-Monday should spread a broad area of moisture east of the
Rockies with some wintry weather possible over far northern
latitudes. A southern stream shortwave crossing northern Mexico and
Texas late this week may also produce some heavy rainfall along
and inland from the western half of the Gulf Coast.

...Guidance/Predictability Assessment...

Latest guidance agrees decently with the larger scale aspects over
the overall pattern but there is still plenty of uncertainty for
details of shortwave energy moving into the West late this week and
continuing inland thereafter, affecting the forecast for low
pressure that should ultimately track northeastward from the
Plains. Trends over the past couple days have been leading toward
an intermediate solution for the leading energy reaching the West
while significant differences develop for the relative emphasis of
leading energy versus trailing energy arriving from the Pacific. At
least there is a somewhat coherent clustering of GFS/ECMWF runs
and most ensemble means as the overall shortwave trough reaches the
eastern half of the country, with surface low pressure near the
eastern Great Lakes as of early next Monday. CMC runs had been too
eager to close off an upper low but the new 00Z run seems to be
tempering that tendency. Machine learning (ML) model spread is
disconcerting though, with a couple suggesting potential for a
faster leading wave and another one hanging back to the southwest,
while another subset is closer to the model/ensemble majority. Off
the West Coast, there is decent clustering for the strong system
near the Pacific Northwest late this week though the new 00Z UKMET
looks somewhat disjointed. There is still a lot of spread for
specifics of the Sunday-Monday system but with the average of
guidance trending somewhat stronger. ML models are still not
developing this system too strongly though.

Latest guidance comparisons based on 18Z/12Z guidance led to
starting Day 3 Thursday with an operational model composite. The
CMC was removed thereafter in favor of the CMCens mean, while the
blend introduced some 18Z GEFS/12Z ECens after early Saturday. Day
7 Monday featured an even weight of models (18Z GFS/12Z ECMWF) and
the means.

...Weather/Hazards Highlights...

Guidance continues to show a late-week threat of locally heavy
rainfall over parts of Texas and then extending eastward, as low
level Gulf moisture and a warm front interact with an upper trough
progressing across northern Mexico and Texas. The Day 4/Thursday
Excessive Rainfall Outlook will now depict a small Slight Risk area
across portions of south-central Texas given an enhanced model
signal for QPF with some convective training possible, even though
there are still some placement differences in the main QPF axis. As
this activity likely drifts eastward, the Day 5/Friday ERO shows a
Marginal Risk area along and somewhat inland from a majority of
the Texas and Louisiana coast. This reflects the best overlap of
guidance and is where heavier rainfall should be more likely based
on instability. The Day 4 period also introduces a Marginal Risk
area for the Pacific Northwest coastal areas with increased model
signal for 1-2 inch totals during this time period.


In addition to supporting Pacific Northwest precipitation, the
strong storm offshore on Thursday may produce some strong winds
near coastal areas. As the system's front and shortwave dynamics
continue eastward, moderate amounts of rain and high elevation snow
will progress across the northern half or so of the West late this
week. Expect Low pressure developing over the Plains and tracking
northeastward to spread an increasingly broad shield of
precipitation across the central and eastern U.S. from the end of
this week into next Monday. Some wintry weather will be possible
over far northern latitudes but otherwise most precipitation should
be in the form of rain, with some potentially on the heavy side.
How much snow falls over the northern Plains during the weekend
will depend on how strongly the system develops, with confidence in
specifics remaining in the lower half of the spectrum. Another
potentially vigorous eastern Pacific system may bring areas of
enhanced precipitation to the West by Sunday-Monday.

The strong upper ridge reaching the Rockies/Plains by Thursday
will bring very warm temperatures to the region, with some areas
over the Plains and eastern Rockies/Midwest seeing up to plus
20-30F anomalies for highs and/or morning lows during Thursday
and/or Friday. Some daily records are possible over the High
Plains. System progression will push a moderated form of this
warmth farther eastward by the weekend, with plus 10-20F anomalies
for highs. However a front settling into the Northeast/Mid-Atlantic
may define a sharp gradient between the warm air and cooler
readings just to the north. Behind the front anchored by the
developing Plains low, near to slightly below normal highs will
progress from the West through the central U.S., followed by a
rebound over and near the Rockies by next Monday.

Rausch


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
348 AM EDT Mon Mar 24 2025

Valid 00Z Tue 25 Mar 2025 - 00Z Tue 01 Apr 2025

Guidance is consistent in showing a front stalling just north the
main islands early this week, leading to fairly weak winds
initially. Trades should pick up some from the east or southeast
Tuesday onward while the front lifts back to the north. The
average of guidance suggests that background flow will be
sufficient to support some windward focus for showers, but at
times it could be weak enough to allow for sea breeze influence.
The late week into early weekend time frame should see the
lightest rainfall as an upper ridge builds into and settles over
the area. As has been the case in recent days, the GFS/GEFS are
weaker with this ridge than the majority of other solutions
including machine learning models. By later Sunday through Monday
consensus shows the low level winds turning more southerly ahead
of a developing system well to the west/northwest of the state.
The leading edge of the moisture axis ahead of the system may edge
into the western islands by next Monday but the heavier rainfall
should remain well westward.

Rausch

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
855 PM EDT Mon Mar 24 2025
Day 1
Valid 01Z Tue Mar 25 2025 - 12Z Tue Mar 25 2025

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

Churchill


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

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
855 PM EDT Mon Mar 24 2025
Day 2
Valid 12Z Tue Mar 25 2025 - 12Z Wed Mar 26 2025

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

Pereira


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

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
855 PM EDT Mon Mar 24 2025
Day 3
Valid 12Z Wed Mar 26 2025 - 12Z Thu Mar 27 2025

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

Pereira

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

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 AM EDT Mon Mar 24 2025


Guidance continues to show a late-week threat of locally heavy
rainfall over parts of Texas and then extending eastward, as low
level Gulf moisture and a warm front interact with an upper trough
progressing across northern Mexico and Texas. There is still
considerable spread for details, tempering confidence. The Day
4/Thursday Excessive Rainfall Outlook stays close to continuity in
depicting a Marginal Risk area over central-southern Texas.
Initially dry ground conditions and guidance spread continue to
preclude an embedded Slight Risk area, though will continue to
monitor trends for improved clustering on the heavier side of the
envelope for any potential upgrade. As this activity likely drifts
eastward, the Day 5/Friday ERO shows a Marginal Risk area along and
somewhat inland from a majority of the Texas and Louisiana coast.
This reflects the best overlap of guidance and is where heavier
rainfall should be more likely based on instability. The Day 4
period maintains a couple regions of interest with no risk areas
for now but require continued monitoring. Dynamical and machine
learning guidance is very mixed regarding potential warm frontal
rainfall over the Midwest. Meanwhile there has been a fair amount
of spread and variability for rainfall along the Pacific Northwest
coast. The best moisture reaches inland by Thursday but instability
under the upper trough could lead to some enhanced rain rates.

In addition to supporting Pacific Northwest precipitation, the
strong storm offshore on Thursday may produce some strong winds
near coastal areas. As the system's front and shortwave dynamics
continue eastward, moderate amounts of rain and high elevation snow
will progress across the northern half or so of the West late this
week. Expect Low pressure developing over the Plains and tracking
northeastward to spread an increasingly broad shield of
precipitation across the central and eastern U.S. from the end of
this week into next Monday. Some wintry weather will be possible
over far northern latitudes but otherwise most precipitation should
be in the form of rain, with some potentially on the heavy side.
How much snow falls over the northern Plains during the weekend
will depend on how strongly the system develops, with confidence in
specifics remaining in the lower half of the spectrum. Another
potentially vigorous eastern Pacific system may bring areas of
enhanced precipitation to the West by Sunday-Monday.

The strong upper ridge reaching the Rockies/Plains by Thursday
will bring very warm temperatures to the region, with some areas
over the Plains and eastern Rockies/Midwest seeing up to plus
20-30F anomalies for highs and/or morning lows during Thursday
and/or Friday. Some daily records are possible over the High
Plains. System progression will push a moderated form of this
warmth farther eastward by the weekend, with plus 10-20F anomalies
for highs. However a front settling into the Northeast/Mid-Atlantic
may define a sharp gradient between the warm air and cooler
readings just to the north. Behind the front anchored by the
developing Plains low, near to slightly below normal highs will
progress from the West through the central U.S., followed by a
rebound over and near the Rockies by next Monday.

Rausch

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 AM EDT Mon Mar 24 2025


Guidance continues to show a late-week threat of locally heavy
rainfall over parts of Texas and then extending eastward, as low
level Gulf moisture and a warm front interact with an upper trough
progressing across northern Mexico and Texas. There is still
considerable spread for details, tempering confidence. The Day
4/Thursday Excessive Rainfall Outlook stays close to continuity in
depicting a Marginal Risk area over central-southern Texas.
Initially dry ground conditions and guidance spread continue to
preclude an embedded Slight Risk area, though will continue to
monitor trends for improved clustering on the heavier side of the
envelope for any potential upgrade. As this activity likely drifts
eastward, the Day 5/Friday ERO shows a Marginal Risk area along and
somewhat inland from a majority of the Texas and Louisiana coast.
This reflects the best overlap of guidance and is where heavier
rainfall should be more likely based on instability. The Day 4
period maintains a couple regions of interest with no risk areas
for now but require continued monitoring. Dynamical and machine
learning guidance is very mixed regarding potential warm frontal
rainfall over the Midwest. Meanwhile there has been a fair amount
of spread and variability for rainfall along the Pacific Northwest
coast. The best moisture reaches inland by Thursday but instability
under the upper trough could lead to some enhanced rain rates.

In addition to supporting Pacific Northwest precipitation, the
strong storm offshore on Thursday may produce some strong winds
near coastal areas. As the system's front and shortwave dynamics
continue eastward, moderate amounts of rain and high elevation snow
will progress across the northern half or so of the West late this
week. Expect Low pressure developing over the Plains and tracking
northeastward to spread an increasingly broad shield of
precipitation across the central and eastern U.S. from the end of
this week into next Monday. Some wintry weather will be possible
over far northern latitudes but otherwise most precipitation should
be in the form of rain, with some potentially on the heavy side.
How much snow falls over the northern Plains during the weekend
will depend on how strongly the system develops, with confidence in
specifics remaining in the lower half of the spectrum. Another
potentially vigorous eastern Pacific system may bring areas of
enhanced precipitation to the West by Sunday-Monday.

The strong upper ridge reaching the Rockies/Plains by Thursday
will bring very warm temperatures to the region, with some areas
over the Plains and eastern Rockies/Midwest seeing up to plus
20-30F anomalies for highs and/or morning lows during Thursday
and/or Friday. Some daily records are possible over the High
Plains. System progression will push a moderated form of this
warmth farther eastward by the weekend, with plus 10-20F anomalies
for highs. However a front settling into the Northeast/Mid-Atlantic
may define a sharp gradient between the warm air and cooler
readings just to the north. Behind the front anchored by the
developing Plains low, near to slightly below normal highs will
progress from the West through the central U.S., followed by a
rebound over and near the Rockies by next Monday.

Rausch

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
248 PM EDT Mon Mar 24 2025

Valid 00Z Tue Mar 25 2025 - 00Z Fri Mar 28 2025



...Great Lakes/Northeast...
Days 1-3...

An active later-season winter pattern will setup across the Great
Lakes and Northeast as troughing amplifies over the east and lobes
of vorticity drop southward out of Canada. This will produce
periodic cool and wintry weather across the region.

The period begins active as a wave of low pressure driven by a
strung out vorticity impulse lifts along the coast of Maine. This
system will move quickly into the Canadian Maritimes by 12Z
Tuesday, but a period of moderate to heavy snow is likely to
continue across Maine before this storm pulls away, and WPC
probabilities indicate a medium chance (30-50%) for an additional
2-4" in far northern Maine.

Behind this wave, cyclonic flow will intensify across the Great
Lakes as the resultant trough amplifies down towards the Mid-
Atlantic states. This will drive increasing CAA over the Great
Lakes, with the core of the coldest 850mb temperatures, falling to
as low as -15 to -18 Celsius, moving over the lakes Tuesday night
into Wednesday morning. This cold core combined with unidirectional
flow across the slowly warming lake waters will result in late-
season lake effect snow (LES), especially in the favored WNW snow
belt regions D1 and D2, with upslope snow into Northern New England
also likely D2. *WPC probabilities for this LES are moderate (50%)
for 4+ inches D1 in the eastern U.P., the far northwest L.P., and
across the Tug Hill Plateau. Probabilities for an additional 4+
inches D2 drop to just 10-30% and focus across the Tug Hill
Plateau.

Finally, an interesting development occurs late D2 into D3 as a
potent shortwave tracks over the Mid-Atlantic states, sharpening
the mid-level trough even more, and then lifts northeast off the
New England Coast. This occurs in tandem with a strengthening jet
streak lifting off into Canada leaving the favorable RRQ east of
New England, into which the amplifying trough will deposit the most
robust height falls. The guidance has trended less amplified with
this evolution, but it still supports a surface low developing and
strengthening into Wednesday morning. Depending on the exact track
of this low, some moderate snowfall may spread across New England
once again Wednesday night into Thursday, but at this time a more
suppressed solution is more likely, resulting in WPC probabilities
that are 10-30% for 4+ inches of snow from the Northeast Kingdom of
VT, across the White Mountains, and into much of northern and
central Maine.


...West Coast...
Day 3...

Impressive trough amplifying west of British Columbia will deepen
into a closed low as it pivots towards the Pacific Northwest coast
Thursday. The core of this low is progged to become quite
amplified, falling below the 0.5 percentile with respect to 700mb
heights (1st percentile with respect to 500mb heights). This is
indicative of a very strong low which will move eastward, but then
get pulled north within the amplified flow, reaching just off
Vancouver Island by the end of the forecast period.

This evolution will have a two-pronged effect on the West Coast.
First, confluent downstream flow will overlap with an intensifying
Pacific jet streak rotating around the base of this trough to
advect deeper moisture onshore, with both GEFS and ECENS IVT
probabilities reaching above 60% for a narrow corridor of 500
kg/m/s. This moisture will be acted upon by mid-level divergence
and upper diffluence to wring out this moisture through increasing
lift to result in widespread precipitation moving from central CA
northward through the Cascades and Olympics. Additionally, W/SW
mid-level flow will efficiently upslope into the terrain, leading
to locally more impressive lift and heavy precipitation across the
terrain.

Snow levels will initially be quite high, 7000-8000 ft, but will
drop steadily to as low as 3000 ft by the end of the forecast
period behind a cold front working to the east. With this event, a
lot of the precipitation occurs behind the cold front, but still
most of the heavy snow should remain above pass levels. WPC
probabilities are high (>70%) for 6+ inches from the Northern
Sierra, through the Shasta/Trinity/Siskiyou region, along the spine
of the Cascades, and into the higher Olympics. Locally 12+ inches
of snow is possible in the highest terrain,


For days 1-3, the probability of significant icing of at least
0.10" is less than 10 percent across the CONUS.


Weiss

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
305 PM EDT Mon Mar 24 2025

Valid 12Z Thu Mar 27 2025 - 12Z Mon Mar 31 2025

19Z Update: The 12Z model guidance suite maintains good synoptic
scale agreement across the Continental U.S. for the end of the work
week. For the storm system developing across the Plains and Upper
Midwest this weekend, the UKMET is a bit more to the northwest of
the model consensus with the front placement, but not a major
outlier. More substantial diffences become apparent with the next
Pacific storm system, with the GFS taking the main low center well
to the north of the CMC and GFS, and lingering model spread in the
wake of that system. For the East Coast, the GFS is faster with the
front exiting the coast Monday night.

Taking these factors into account, Thursday and Friday incorporated
a general deterministic model blend, and then the ensemble means
were gradually increased to about 40% by early next week. The
previous forecast discussion is appended below for reference.
/Hamrick
-------------------

...Overview...

Most guidance shows a reloading mean trough over the eastern
Pacific with a strong system affecting the Pacific Northwest
Thursday into Friday with potential for another meaningful system
to affect the West Coast by Sunday-Monday. The downstream pattern
looks moderately progressive, with a very warm Rockies/Plains ridge
eventually moving off the East Coast while trailing shortwave
energy supports low pressure that should track northeastward from
the Plains during the weekend into early next week. The eastern
Pacific systems will bring areas of enhanced precipitation to the
West Coast while the system affecting the central/eastern U.S. by
Saturday-Monday should spread a broad area of moisture east of the
Rockies with some wintry weather possible over far northern
latitudes. A southern stream shortwave crossing northern Mexico and
Texas late this week may also produce some heavy rainfall along
and inland from the western half of the Gulf Coast.

...Guidance/Predictability Assessment...

Latest guidance agrees decently with the larger scale aspects over
the overall pattern but there is still plenty of uncertainty for
details of shortwave energy moving into the West late this week and
continuing inland thereafter, affecting the forecast for low
pressure that should ultimately track northeastward from the
Plains. Trends over the past couple days have been leading toward
an intermediate solution for the leading energy reaching the West
while significant differences develop for the relative emphasis of
leading energy versus trailing energy arriving from the Pacific. At
least there is a somewhat coherent clustering of GFS/ECMWF runs
and most ensemble means as the overall shortwave trough reaches the
eastern half of the country, with surface low pressure near the
eastern Great Lakes as of early next Monday. CMC runs had been too
eager to close off an upper low but the new 00Z run seems to be
tempering that tendency. Machine learning (ML) model spread is
disconcerting though, with a couple suggesting potential for a
faster leading wave and another one hanging back to the southwest,
while another subset is closer to the model/ensemble majority. Off
the West Coast, there is decent clustering for the strong system
near the Pacific Northwest late this week though the new 00Z UKMET
looks somewhat disjointed. There is still a lot of spread for
specifics of the Sunday-Monday system but with the average of
guidance trending somewhat stronger. ML models are still not
developing this system too strongly though.

Latest guidance comparisons based on 18Z/12Z guidance led to
starting Day 3 Thursday with an operational model composite. The
CMC was removed thereafter in favor of the CMCens mean, while the
blend introduced some 18Z GEFS/12Z ECens after early Saturday. Day
7 Monday featured an even weight of models (18Z GFS/12Z ECMWF) and
the means.

...Weather/Hazards Highlights...

Guidance continues to show a late-week threat of locally heavy
rainfall over parts of Texas and then extending eastward, as low
level Gulf moisture and a warm front interact with an upper trough
progressing across northern Mexico and Texas. The Day 4/Thursday
Excessive Rainfall Outlook will now depict a small Slight Risk area
across portions of south-central Texas given an enhanced model
signal for QPF with some convective training possible, even though
there are still some placement differences in the main QPF axis. As
this activity likely drifts eastward, the Day 5/Friday ERO shows a
Marginal Risk area along and somewhat inland from a majority of
the Texas and Louisiana coast. This reflects the best overlap of
guidance and is where heavier rainfall should be more likely based
on instability. The Day 4 period also introduces a Marginal Risk
area for the Pacific Northwest coastal areas with increased model
signal for 1-2 inch totals during this time period.


In addition to supporting Pacific Northwest precipitation, the
strong storm offshore on Thursday may produce some strong winds
near coastal areas. As the system's front and shortwave dynamics
continue eastward, moderate amounts of rain and high elevation snow
will progress across the northern half or so of the West late this
week. Expect Low pressure developing over the Plains and tracking
northeastward to spread an increasingly broad shield of
precipitation across the central and eastern U.S. from the end of
this week into next Monday. Some wintry weather will be possible
over far northern latitudes but otherwise most precipitation should
be in the form of rain, with some potentially on the heavy side.
How much snow falls over the northern Plains during the weekend
will depend on how strongly the system develops, with confidence in
specifics remaining in the lower half of the spectrum. Another
potentially vigorous eastern Pacific system may bring areas of
enhanced precipitation to the West by Sunday-Monday.

The strong upper ridge reaching the Rockies/Plains by Thursday
will bring very warm temperatures to the region, with some areas
over the Plains and eastern Rockies/Midwest seeing up to plus
20-30F anomalies for highs and/or morning lows during Thursday
and/or Friday. Some daily records are possible over the High
Plains. System progression will push a moderated form of this
warmth farther eastward by the weekend, with plus 10-20F anomalies
for highs. However a front settling into the Northeast/Mid-Atlantic
may define a sharp gradient between the warm air and cooler
readings just to the north. Behind the front anchored by the
developing Plains low, near to slightly below normal highs will
progress from the West through the central U.S., followed by a
rebound over and near the Rockies by next Monday.

Rausch


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