RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Fri Mar 20 06:18:01 UTC 2026.
No Mesoscale Discussions are in effect as of Fri Mar 20 06:18:01 UTC 2026.
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 AM CDT Fri Mar 20 2026
Valid 201200Z - 211200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
OHIO VALLEY REGION...
...SUMMARY...
Strong to locally severe thunderstorms are possible across parts of
the Upper Ohio Valley, mainly late this afternoon into the evening.
...Upper Ohio Valley...
Dominant upper ridge will hold across the southwestern parts of the
CONUS through the day1 period, but this feature will influence most
of the western US by forcing stronger westerlies to near the
international border/Great Lakes region. Latest model guidance
suggests a weak shortwave trough will top the ridge and dig
southeast across the Great Lakes into the upper OH Valley by 21/00z.
As this occurs weak midlevel height falls will be noted across
eastern OH/PA as a surface cold front settles across western
NY-northern OH-central IN by late afternoon.
Early this morning, boundary-layer moisture is quite dry across much
of the OH Valley with only upper 30s/lower 40s surface dew points
observed. Deepening westerly flow suggests low-level moisture across
southeast MO/northern AR will advect toward the upper OH Valley,
possibly arriving prior to the frontal passage. Even so, dew points
within this source region are only in the mid 40s to lower 50s.
Forecast soundings for mid afternoon suggest modest boundary-layer
heating such that 0-3km lapse rates should be on the order of 7 C/km
with MUCAPE around 500-700 J/kg. Current thinking is scattered
convection will develop along/ahead of the cold front by late
afternoon, then spread southeast before weakening with loss of
daytime heating. Strong deep-layer shear favors organized updrafts
and the greatest risk should be gusty winds with marginally severe
hail.
..Darrow/Chalmers.. 03/20/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Fri Mar 20 2026
Valid 211200Z - 221200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Isolated to scattered thunderstorms are possible on Saturday from
the Tennessee Valley into the southern Appalachians. Thunderstorms
will also be possible in Wisconsin and Lower Michigan Saturday
night.
...DISCUSSION...
An upper-level ridge will move into the Rockies on Saturday, as
northwesterly mid-level flow remains from the Great Plains to the
Eastern Seaboard. Within the flow, a shortwave mid-level trough will
move through the Tennessee Valley. Ahead of this feature, scattered
thunderstorms will be possible during the day from southern Kentucky
and Tennessee southeastward across northern Georgia and South
Carolina. Isolated thunderstorms will also be possible Saturday
night from Wisconsin into western Michigan, as a mid-level jet
streak moves eastward across the Great Lakes. No severe
thunderstorms are forecast Saturday and Saturday night.
..Broyles.. 03/20/2026
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0115 AM CDT Fri Mar 20 2026
Valid 201200Z - 211200Z
...CRITICAL FIRE WEATHER AREA FOR CENTRAL AND EASTERN WYOMING...
...Synopsis...
A persistent upper-level ridge will remain centered over the
Southwest today with modest northwest flow aloft across the
central/northern High Plains. Surface high pressure over the
Intermountain West coupled with lee troughing across the northern
Great Plains will continue to favor a downslope wind regime, with
dry and windy conditions forecast to support elevated to critical
fire weather concerns across portions of the central and northern
High Plains.
...Central/Northern High Plains...
Record warm temperatures continue across much of the West amid an
anomalously strong upper-level ridge centered across the Southwest.
With high pressure remaining in place across the Intermountain West
and lee troughing across the northern Great Plains, a continuing
downslope wind regime is forecast to yield sustained
west-northwesterly surface winds of 20-25 mph across portions of
central/eastern Wyoming. Poor overnight RH recoveries have been
noted via recent surface observations with further RH reductions to
10-20% forecast this afternoon. Coupled with receptive fuels, this
is expected to support critical fire weather conditions across
central/eastern Wyoming today. Elevated fire weather concerns are
also forecast across adjacent areas of the western Wyoming Basin and
portions of southwestern South Dakota and western Nebraska where
surface winds of 15-20 mph are expected to overlap minimum RH values
of 10-20%.
Fuels remain more marginal farther to the north across much of
southern Montana and portions of extreme southwestern North Dakota
and northwestern South Dakota; however, continued warm/dry
conditions have supported some drying of fine fuels along with
recent fire activity. Given this, elevated fire weather conditions
are expected this afternoon as RH values are forecast to range from
15-25% amid stronger sustained westerly winds of 15-25 mph. 40+
knots of 700 mb flow across this region coupled with deep boundary
layer mixing may also support occasional wind gusts of 30-40 mph.
...Central Nevada into southern Oregon...
Guidance continues to indicate localized potential for sustained
southwesterly surface winds of 10-15 mph this afternoon as the
surface pressure gradient tightens ahead of an approaching cold
front. With RH values forecast to fall to 10-15%, localized elevated
fire weather concerns may materialize across portions of southern
Oregon into central Nevada, especially in areas that favor
terrain-induced wind enhancements. However, widespread elevated
conditions are not expected at this time given marginal early season
fuel conditions and sporadic coverage of coincident elevated wind/RH
criteria.
..Chalmers.. 03/20/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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