RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Thu Mar 19 21:42:01 UTC 2026.
No Mesoscale Discussions are in effect as of Thu Mar 19 21:42:01 UTC 2026.
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Thu Mar 19 2026
Valid 192000Z - 201200Z
...NO THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Thunderstorms are not forecast across the U.S. today or tonight.
...20Z Update...
The previous forecast (see below) remains unchanged.
..Squitieri.. 03/19/2026
.PREV DISCUSSION... /ISSUED 1049 AM CDT Thu Mar 19 2026/
...Synopsis...
Surface high pressure over the Southeast and a dry airmass over the
Gulf Basin will result in a persistent stable environment east of
the Rockies, precluding thunderstorm activity. A drier airmass is
also expected across south FL compared to previous days. Offshore
thunderstorms may approach the east-central FL coast tonight.
However, meager instability and nebulous forcing will likely limit
any thunderstorm coverage on land to less than 10 percent.
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Thu Mar 19 2026
Valid 201200Z - 211200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS CENTERED ON THE
UPPER OHIO VALLEY...
...SUMMARY...
Strong to locally severe thunderstorms are possible across parts of
the Upper Ohio Valley, mainly late Friday afternoon into Friday
evening.
...Synopsis...
An upper ridge will remain in place over the Southwest on Friday,
while a large-scale upper trough will cover much of the eastern
CONUS. Within the large-scale trough, an embedded shortwave will
move from the Upper Great Lakes towards the northern Mid Atlantic
and New England. A surface low will move from parts of lower MI
toward New England through the period, as trailing cold front moves
across the Ohio Valley and Mid Atlantic.
...Parts of the mid/upper Ohio Valley...
Modest low-level moisture will return through the day along/ahead of
the approaching cold front across parts of the Ohio Valley/Allegheny
Plateau region. Regarding prefrontal dewpoints, guidance generally
ranges from the low 50s F (HRRR/WRF-ARW) to mid/upper 50s F (NAM and
other HREF members). In the presence of strong deep-layer
flow/shear, the magnitude of moisture return will determine the
level and areal extent of any organized severe potential.
If moisture return becomes sufficient to support MLCAPE of around
500 J/kg or greater, then a few stronger updrafts and perhaps
marginal supercell structures could develop by late afternoon or
early evening, as convective temperatures are approached or breached
and glancing large-scale ascent impinges upon the region. Despite
the generally weak instability, any robust storms could pose a
threat of marginally severe hail and perhaps locally gusty/damaging
winds, given the presence of favorable shear and rather cold
temperatures aloft. A brief tornado also cannot be ruled out, though
this will be more conditional on richer low-level moisture return
and maintenance of surface-based convection.
With generally low-quality moisture noted in Thursday morning
observations, sufficient moisture return for an organized severe
threat on Friday remains quite uncertain. However, given the
presence of very favorable wind profiles and at least some signal
for near-surface-based storm development during the late afternoon
and evening, a conditional Marginal Risk has been added for Friday
across parts of the Upper Ohio Valley. A conditionally favorable
environment will extend outside of the Marginal Risk into parts of
the mid/lower Ohio Valley, but the signal for storm development
currently decreases substantially with southwestward extent.
..Dean.. 03/19/2026
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0229 PM CDT Thu Mar 19 2026
Valid 211200Z - 221200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Isolated general thunderstorms are possible Saturday over the
Tennessee Valley to southern Appalachians, and also across parts of
the Upper Midwest.
...Synopsis...
Some deamplification of the upper-level pattern is expected on
Saturday, with a transition to more zonal flow across much of the
western and central CONUS. A large-scale upper trough will remain in
place across much of the East, with a weak embedded shortwave
expected to move from the Mid MS Valley toward the Southeast.
...TN Valley into parts of GA and the Carolinas...
A weak front that moves into the region late D2/Friday is forecast
to stall and potentially become rather ill-defined with time, as a
surface low deepens well to the northwest across the north-central
Plains. A remnant moisture/instability gradient is still depicted by
guidance to be draped from TN into the southern Appalachians and SC
by Saturday afternoon. Modest destabilization (with MLCAPE
potentially approaching 1000 J/kg) will be possible along/south of
the remnant boundary, and isolated storm development may occur as
the weakening shortwave trough moves across the region.
Deep-layer shear will generally remain rather modest within the weak
northwest-flow regime, and storm coverage may tend to remain limited
due to weak large-scale ascent. As a result, confidence in an
organized-severe threat is currently too low for probabilities,
though isolated strong storms with localized hail and/or wind-damage
potential cannot be ruled out, and a Marginal Risk may eventually be
needed for parts of the region.
..Dean.. 03/19/2026
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0136 PM CDT Thu Mar 19 2026
Valid 201200Z - 211200Z
...CRITICAL FIRE WEATHER AREA FOR CENTRAL AND EASTERN WYOMING...
No changes were made to the drawn areas. The expected conditions
remain on track with the latest forecast guidance. Across portions
of central/northern Nevada and extreme southeast Oregon, expect to
see localized sustained winds of 10-15 mph and RHs down to 10-15%
during peak heating on Day 2/Friday. Given the marginal early season
fuel conditions and sporadic coverage of coincident winds and RH,
fire weather highlights were not introduced with this issuance.
However, trends over the western Great Basin and nearby areas will
be watched with future forecasts.
..Stearns/Williams.. 03/19/2026
.PREV DISCUSSION... /ISSUED 0204 AM CDT Thu Mar 19 2026/
...Synopsis...
A persistent upper-level ridge will remain centered over the
Southwest on D2/Friday, with modest northwest flow aloft persisting
across the central/northern High Plains. Surface high pressure over
the Intermountain West coupled with lee troughing across the
northern Plains will support a continued downslope wind regime, with
dry/windy conditions forecast to yield elevated to critical fire
weather concerns across portions of the central and northern High
Plains.
...Central/Northern High Plains...
Anomalously strong upper-level ridging across the Southwest will
continue to support the potential for record warm temperatures
across much of the West. With high pressure remaining positioned
across the Intermountain West and lee troughing in place across the
northern Great Plains, a persistent downslope wind regime is
forecast to yield sustained west-northwesterly surface winds of
15-25 mph across much of the central/northern High Plains. Coupled
with reduced RH values of 10-15% and receptive fuels, this will
support critical fire weather conditions across portions of
central/eastern Wyoming. Elevated fire weather concerns are forecast
across adjacent areas of the western Wyoming Basin and portions of
southwestern South Dakota and western Nebraska where lighter surface
winds of 15-20 mph are forecast to overlap reduced minimum RH values
of 10-15%. Farther north across much of southern Montana, RH values
are expected to remain more marginal (15-25%); however, ongoing fire
activity and sustained westerly surface winds of 15-25 mph warrant
the addition of Elevated fire weather highlights.
...Oregon...
Some guidance indicates westerly surface winds will strengthen amid
a tightening surface pressure gradient ahead of an approaching cold
front through D2/Friday. Continued dry/windy conditions may support
localized elevated fire weather concerns, but remaining uncertainty
regarding the strength and duration of stronger winds as well as how
low RH will fall in the afternoon precludes the inclusion of
Elevated fire weather highlights at this time. Conditions will
continue to be monitored for future updates.
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0428 PM CDT Thu Mar 19 2026
Valid 211200Z - 271200Z
A shortwave trough will crest the existing well-established
Intermountain West ridge, moving through the Pacific Northwest on
Day 3/Saturday before crossing the northern Plains and Great Lakes
region Day 4/Sunday into Day 5/Monday. The latest forecast guidance
continues to break down the upper-level ridge, at least temporarily,
shifting the corridor of stronger mid-level flow further south.
Meanwhile, at the surface, a cold front will surge south through the
northern and central Plains on Day 3/Saturday and Day 4/Sunday.
While uncertainty remains in the timing of this front, forecast
guidance suggests that it will be dry. This would present concerns
both ahead of and behind the front as it passes. On Day 5/Monday and
Day 6/Tuesday, the ridge will again build over the Intermountain
West with a potential breakdown on Day 7/Wednesday or Day 8/Thursday
with the passing of another upper-level shortwave trough across the
northern CONUS.
On Day 3/Saturday, moderate westerly flow aloft will remain in place
over much of the central High Plains. Record warm temperatures are
likely for yet another day as the ridge builds across the western
US. A 70% area was introduced for Day 3/Saturday, reflecting high
confidence in sustained westerly winds of 20-30 mph overlapping with
RH values of 10-20% during peak heating. Additionally, the 40% area
was significantly expanded to include the southeastern half of the
Great Basin, the northern half of the Southwest, and portions of the
central and southern High Plains. While much of the high elevations
of the central Rockies are within the drawn area, fuel conditions
and snow cover will preclude any fire weather concerns in those
areas.
On Day 4/Sunday, the 40% area was again significantly expanded to
account for strengthening southwesterly flow across large portions
of New Mexico, Texas, and Oklahoma. However, the northern extent of
this area will likely be adjusted to account for the timing of the
frontal boundary. While this cold front will be impactful in
bringing stronger winds to the central portions of the CONUS,
temperatures behind the front will barely fall back to seasonal
averages.
On Day 5/Monday, deep surface mixing under westerly flow will again
impact southern Wyoming resulting in another day of 10-20 mph winds
and RHs down to 15-20%. Over the lee side of the central
Appalachians, expect post-frontal northwesterly winds of 10-15 mph
to combine with RHs of 20-30% resulting in an additional 40% area.
As the ridge begins to build back over the western US on Day
6/Tuesday, fire weather conditions appear to remain subdued. By Day
7/Wednesday, the latest forecast guidance is hinting at yet another
period of hot, dry, and windy conditions focused over much of
Wyoming and surrounding areas. A 40% area was included for this
region as deep boundary layer mixing will again introduce a corridor
of strong westerly winds of 15-25 mph coinciding with RHs of 10-20%.
Record temperatures and dry conditions will continue to desiccate
fuels over several consecutive days across the southern two-thirds
of the western US through the outlook period. Independent of wind
speeds, high vapor pressure deficits and low RH values suggest
extended burn periods across these areas where fuels become
increasingly receptive to ignition. One piece of good news is that
far northern portions of the CONUS, including areas highlighted in
the Day 1/Thursday through Day 2/Friday time frame may receive at
least minimal mounts of precipitation as each of the aforementioned
troughs move across the International Border with Canada.
..Stearns/Williams.. 03/19/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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