Weather Prediction Center

National Oceanic and Atmospheric Administration

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
251 PM EDT Thu Mar 20 2025

Valid 00Z Fri Mar 21 2025 - 00Z Sun Mar 23 2025

...Wet weather continues across the Pacific Northwest into the Northern
Rockies...

...A fire weather threat across large portions of the Central to Southern
Plains, portions of the western to central Gulf Coast and east central to
southeast Florida...

...Spring like temperatures across much of the Lower 48...

The first day of Spring will see a less snow and severe thunderstorm
impacts across much of the nation in the wake of the blizzard/snowstorm
that affected areas from the Central Plains into the Upper Great Lakes
having moved into southeast Canada. Cold air in the wake of this storm
will continue press eastward tonight across much of the east, bringing
cooler air across areas seeing very mild temperatures Thursday afternoon.
The cold front ushering this cooler air eastward will have showers and
thunderstorms along it as it presses eastward along the eastern seaboard.
However, thunderstorms activity is not expected to be as strong as what
occurred Wednesday afternoon/evening across the Mid-West, Ohio and
Tennessee Valley region, with no areas of severe thunderstorms expected
today.

The above mentioned colder air pushing eastward today will keep
temperatures slightly below average over the Southeast and Florida on
Friday and across Florida on Saturday. Slightly below average
temperatures also on tap for the next two days from the Northern Rockies
into the Pacific Northwest. However, arctic air will remain absent from
the Lower 48 for the first few days of Spring.

The recent wet weather pattern over the Pacific Northwest expected to
continue over the next few days. The next in a series of frontal
boundaries moving across the northeast Pacific will bring the next round
of moderate to heavy precipitation into the Pacific Northwest late this
afternoon into Thursday evening, followed by more rains and higher
elevation snows for the Pacific Northwest and Northern Rockies on Friday.

Dry and breezy conditions expected across much of the Central to Southern
Plains, Lower Mississippi Valley, Gulf Coast and Florida over the next few
days. This will support the continuation of a fire risk across portions
of these areas. Red Flag warning are currently in effect across potions
of the Plains, Gulf coast and east central to southeast Florida, affecting
nearly 25 million people.

Oravec


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

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
301 PM EDT Thu Mar 20 2025

Valid 12Z Sun Mar 23 2025 - 12Z Thu Mar 27 2025


...Overview and Guidance/Predictability Assessment...

Progressive upper flow into the weekend in two streams will
amplify into next week with the development of a warming/building
West Coast ridge and a cooling/deepening and unsettling east-
central U.S. trough.

Operational and ML models capture the evolution of the overall
synoptic pattern across the lower 48 for next week. All models are
in reasonably good agreement on the day 3 pattern, save for
several
00z GEFS members which depict a slower Central U.S. trough. This
trend continues through the rest of the period. Deterministic
guidance are more progressive than the ensembles and operational
AIFS with the upper low propagating through the Great Lakes region
on day 4. The upper pattern simplifies into mean troughing in the
East and mean ridging in the West beginning on day 5. A Euro-
centric general model blend is used from day 5 through 7.


...Weather/Hazards Highlights...

Shortwave troughs riding a Western ridge will shift from the
northeast Pacific into BC Sunday with a potent moisture plume to
the south that pushes across western WA. A Marginal Risk for
excessive rainfall is maintained only into Day 4/Sunday for
coastal Washington as compounding effects of multiple preceding
bouts of precipitation may lead to local runoff issues. Amplified
upper trough development and deep system genesis early-mid next
week should prove slow to approach the West Coast, but should
spread organized precipitation back into the Northwest in about a
week.

The amplifying low over the northern Plains into the Great Lakes
Sunday will draw broad scale Gulf moisture up the MS Valley and
support a heavy rain and a severe weather threat for parts of Mid-
South and lower MS Valley into the TN Valley. The Day 4/Sunday ERO
Marginal Risk area is maintained for the Lower Mississippi and
Tennessee Valleys. Enhanced rains then spread as a wavy cold front
sweeps across the Southeast/Eastern Seaboard Monday into Tuesday. A
WPC Day 5/Monday ERO Marginal Risk area was maintained to cover
lingering and training cell potential over the eastern Gulf Coast.

Meanwhile on the northern periphery of the expanding precipitation
shield, reinforcing cold air wrapping around the main deep low
appears to support a heavy snow threat for the Great Lakes region
Sunday into Monday, spreading over the northern and interior
Northeast into Monday and Tuesday with closed upper low/trough
approach and with coastal New England triple-point low development.

An amplifying ridge in the West will support an early return of
spring-like temperatures in the West next week. Highs are expected
to be between 15-30 degrees above average for much of the region.
There's increasing potential for widespread high/low records to be
tied/broken next Tuesday/Wednesday. This includes much of the
Desert Southwest, where some places may experience daytime highs
over 100 degrees.

Kebede/Schichtel


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
301 AM EDT Thu Mar 20 2025

Valid 00Z Fri 21 Mar 2025 - 00Z Fri 28 Mar 2025

A composite of favored and reasonably well clustered model and
ensemble mean guidance offers an island trade flow pattern with
generally below normal available moisture over the next few days.
This occurs as nearby upper troughing loses influence and as
surface high pressure bridges from the north to settle to the
northeast of the state. Guidance then signals passage of an
energetic mid-latitude upper trough to the north of the state
later weekend and early next week that would disrupt trades while
forcing a moisture pooling and enhanced rainfall focusing cold
front into the islands early next week, albeit with push trending
slightly less ardent in latest guidance overall.

Schichtel

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
820 PM EDT Thu Mar 20 2025
Day 1
Valid 01Z Fri Mar 21 2025 - 12Z Fri Mar 21 2025

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

Chenard


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

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
820 PM EDT Thu Mar 20 2025
Day 2
Valid 12Z Fri Mar 21 2025 - 12Z Sat Mar 22 2025

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
820 PM EDT Thu Mar 20 2025
Day 3
Valid 12Z Sat Mar 22 2025 - 12Z Sun Mar 23 2025

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
301 PM EDT Thu Mar 20 2025


Shortwave troughs riding a Western ridge will shift from the
northeast Pacific into BC Sunday with a potent moisture plume to
the south that pushes across western WA. A Marginal Risk for
excessive rainfall is maintained only into Day 4/Sunday for
coastal Washington as compounding effects of multiple preceding
bouts of precipitation may lead to local runoff issues. Amplified
upper trough development and deep system genesis early-mid next
week should prove slow to approach the West Coast, but should
spread organized precipitation back into the Northwest in about a
week.

The amplifying low over the northern Plains into the Great Lakes
Sunday will draw broad scale Gulf moisture up the MS Valley and
support a heavy rain and a severe weather threat for parts of Mid-
South and lower MS Valley into the TN Valley. The Day 4/Sunday ERO
Marginal Risk area is maintained for the Lower Mississippi and
Tennessee Valleys. Enhanced rains then spread as a wavy cold front
sweeps across the Southeast/Eastern Seaboard Monday into Tuesday. A
WPC Day 5/Monday ERO Marginal Risk area was maintained to cover
lingering and training cell potential over the eastern Gulf Coast.

Meanwhile on the northern periphery of the expanding precipitation
shield, reinforcing cold air wrapping around the main deep low
appears to support a heavy snow threat for the Great Lakes region
Sunday into Monday, spreading over the northern and interior
Northeast into Monday and Tuesday with closed upper low/trough
approach and with coastal New England triple-point low development.

An amplifying ridge in the West will support an early return of
spring-like temperatures in the West next week. Highs are expected
to be between 15-30 degrees above average for much of the region.
There's increasing potential for widespread high/low records to be
tied/broken next Tuesday/Wednesday. This includes much of the
Desert Southwest, where some places may experience daytime highs
over 100 degrees.

Kebede/Schichtel

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
301 PM EDT Thu Mar 20 2025


Shortwave troughs riding a Western ridge will shift from the
northeast Pacific into BC Sunday with a potent moisture plume to
the south that pushes across western WA. A Marginal Risk for
excessive rainfall is maintained only into Day 4/Sunday for
coastal Washington as compounding effects of multiple preceding
bouts of precipitation may lead to local runoff issues. Amplified
upper trough development and deep system genesis early-mid next
week should prove slow to approach the West Coast, but should
spread organized precipitation back into the Northwest in about a
week.

The amplifying low over the northern Plains into the Great Lakes
Sunday will draw broad scale Gulf moisture up the MS Valley and
support a heavy rain and a severe weather threat for parts of Mid-
South and lower MS Valley into the TN Valley. The Day 4/Sunday ERO
Marginal Risk area is maintained for the Lower Mississippi and
Tennessee Valleys. Enhanced rains then spread as a wavy cold front
sweeps across the Southeast/Eastern Seaboard Monday into Tuesday. A
WPC Day 5/Monday ERO Marginal Risk area was maintained to cover
lingering and training cell potential over the eastern Gulf Coast.

Meanwhile on the northern periphery of the expanding precipitation
shield, reinforcing cold air wrapping around the main deep low
appears to support a heavy snow threat for the Great Lakes region
Sunday into Monday, spreading over the northern and interior
Northeast into Monday and Tuesday with closed upper low/trough
approach and with coastal New England triple-point low development.

An amplifying ridge in the West will support an early return of
spring-like temperatures in the West next week. Highs are expected
to be between 15-30 degrees above average for much of the region.
There's increasing potential for widespread high/low records to be
tied/broken next Tuesday/Wednesday. This includes much of the
Desert Southwest, where some places may experience daytime highs
over 100 degrees.

Kebede/Schichtel

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
220 PM EDT Thu Mar 20 2025

Valid 12Z Thu Mar 20 2025 - 12Z Sun Mar 23 2025


...Pacific/Interior Northwest to Central Rockies...
Days 1-3...

An active Pacific jet stream pattern will keep periods of mountain
snow in the forecast over the next few days. This is largely due to
a persistent troughing pattern over the Gulf of Alaska that
continues to reload this active pattern with storm systems racing
across the North Pacific that eventually reach the northwestern
U.S.. The Washington Cascades and Olympics above 3,500ft will be
the epicenter for the heaviest snowfall where they are more ideally
placed with the best surge of Pacific moisture, favorable upslope
enhancement, and their placement beneath a strong 130kt 250mb jet
streak aloft. The Oregon Cascades will also be on the receiving
end of accumulating snow, but with higher snow levels farther
south, elevations above 4,500ft will be most favored for heavy
snowfall through Friday. Following a brief break in the active
pattern Saturday morning, an approaching warm front from the next
storm system in line over the Gulf of Alaska will cause noticeably
higher snow levels over the Olympics and Washington Cascades
Saturday night and Sunday. Snow accumulations will likely range
between 1-3 feet in these ranges with some of the tallest peaks of
the Olympics and Washington Cascades topping 4 feet of snowfall
through Sunday.

This same plume of Pacific moisture and the aforementioned jet
streak aloft will advance inland across mountain ranges that
include the Blue, Sawtooth, Bitterroots, Lewis Range, Absaroka, and
Tetons tonight, Friday, and into Saturday morning. Elevations above
5,000ft in the Blue, Sawtooth, Bitterroots, and Lewis Range are
favored to receive as much as 1-2 feet of snow through Saturday
morning. Farther south, elevations above 7,000ft are favored in the
Absaroka and Tetons, as well as other neighboring ranges that
include the Big Snowy, Little Belt, Big Horns, and Bear River
ranges. Snowfall totals of 8-12" will be most common in these
mountain ranges, with the Tetons having better odds of seeing some
snowfall totals topping 2 feet. Lastly, some of this Pacific
moisture will bleed far enough south to reach the Colorado
Rockies and southern Wyoming Rockies Friday night and into
Saturday. Elevations above 9,000ft will be most likely to see
snowfall accumulations >6" with the tallest peaks of the Colorado
Rockies receiving over a foot before the snow tapers off Saturday
night.


...Northern Appalachians & Northeast...
Day 1...

This afternoon, a lobe of 500mb vorticity tracking towards the
Southeast will foster increasing upper-level ascent over the
Northeast coast. At the same time, a frontal boundary approaching
from the west will align itself along a more baroclinically favored
area along the Northeast coast that will give rise to a developing
wave of low pressure Thursday night near Long Island. With the
developing low positioned beneath the diffluent left-exit region of
a 250mb jet streak, low pressure will organize quickly and
southerly flow off the Gulf Stream will advect rich Atlantic
moisture around the northern and western flanks of the low. After
initially starting out as rain, a transition to snow will ensue
from the Catskills and Adirondacks on east through the Berkshires,
Green, and White Mountains on Friday. The storm is a quick mover
thanks to the next upper trough within the active jet stream
pattern over the Great Lakes. Any lingering snow in parts of
northern Maine should conclude Friday night. WPC probabilities
depict low-to-moderate chances (20-50%) for snowfall >2" in the
higher elevations of the Green and White Mountains. The tallest
peaks, including Mount Washington, could see some snowfall totals
>4" through Friday afternoon.


...Upper Midwest & Great Lakes...
Day 3...

A steepening upper-level trough over the Northern Plains will
provide modest ascent aloft and strengthen low pressure over the
Dakotas. Out ahead of this upper-level trough is increasing
850-700mb WAA that gives rise to low-mid level FGEN over the Upper
Midwest and into the northern Great Lakes Sunday morning. As Sunday
unfolds, a more organized 850mb low is likely to form over
northwest Wisconsin with a much of the atmospheric column well
saturated over northern Minnesota, northern Wisconsin, and the
Michigan U.P.. Based on the track of the 850mb low and the pivoting
deformation axis on the storm's northwest flank, it is northern
Minnesota that presently features the best odds (50-70% moderate
chances) for >4" of snowfall. The Minnesota Arrowhead, with the
added benefit of easterly flow that provides additional lake-
enhancement, has low-to-moderate chances (30-50%) for snowfall
totals >8". Northern Wisconsin and the Michigan U.P. may mix with
rain or stay a wintry mix longer, which combined with generally
lower SLRs may keep snowfall totals a bit more capped compared to
northern Minnesota. However, it will be the CAA on the back side of
the storm and across Lake Superior Sunday night when these areas
see their best chances for measurable snow.


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


Mullinax

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
301 PM EDT Thu Mar 20 2025

Valid 12Z Sun Mar 23 2025 - 12Z Thu Mar 27 2025


...Overview and Guidance/Predictability Assessment...

Progressive upper flow into the weekend in two streams will
amplify into next week with the development of a warming/building
West Coast ridge and a cooling/deepening and unsettling east-
central U.S. trough.

Operational and ML models capture the evolution of the overall
synoptic pattern across the lower 48 for next week. All models are
in reasonably good agreement on the day 3 pattern, save for
several
00z GEFS members which depict a slower Central U.S. trough. This
trend continues through the rest of the period. Deterministic
guidance are more progressive than the ensembles and operational
AIFS with the upper low propagating through the Great Lakes region
on day 4. The upper pattern simplifies into mean troughing in the
East and mean ridging in the West beginning on day 5. A Euro-
centric general model blend is used from day 5 through 7.


...Weather/Hazards Highlights...

Shortwave troughs riding a Western ridge will shift from the
northeast Pacific into BC Sunday with a potent moisture plume to
the south that pushes across western WA. A Marginal Risk for
excessive rainfall is maintained only into Day 4/Sunday for
coastal Washington as compounding effects of multiple preceding
bouts of precipitation may lead to local runoff issues. Amplified
upper trough development and deep system genesis early-mid next
week should prove slow to approach the West Coast, but should
spread organized precipitation back into the Northwest in about a
week.

The amplifying low over the northern Plains into the Great Lakes
Sunday will draw broad scale Gulf moisture up the MS Valley and
support a heavy rain and a severe weather threat for parts of Mid-
South and lower MS Valley into the TN Valley. The Day 4/Sunday ERO
Marginal Risk area is maintained for the Lower Mississippi and
Tennessee Valleys. Enhanced rains then spread as a wavy cold front
sweeps across the Southeast/Eastern Seaboard Monday into Tuesday. A
WPC Day 5/Monday ERO Marginal Risk area was maintained to cover
lingering and training cell potential over the eastern Gulf Coast.

Meanwhile on the northern periphery of the expanding precipitation
shield, reinforcing cold air wrapping around the main deep low
appears to support a heavy snow threat for the Great Lakes region
Sunday into Monday, spreading over the northern and interior
Northeast into Monday and Tuesday with closed upper low/trough
approach and with coastal New England triple-point low development.

An amplifying ridge in the West will support an early return of
spring-like temperatures in the West next week. Highs are expected
to be between 15-30 degrees above average for much of the region.
There's increasing potential for widespread high/low records to be
tied/broken next Tuesday/Wednesday. This includes much of the
Desert Southwest, where some places may experience daytime highs
over 100 degrees.

Kebede/Schichtel


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