No watches are valid as of Fri Oct 16 00:06:01 UTC 2026.MD 2380 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR FAR SOUTHEASTERN ILLINOIS INTO SOUTHERN INDIANA
Mesoscale Discussion 2380
NWS Storm Prediction Center Norman OK
0608 PM CDT Thu Oct 15 2026
Areas affected...far southeastern Illinois into southern Indiana
Concerning...Severe potential...Watch possible
Valid 152308Z - 160015Z
Probability of Watch Issuance...40 percent
SUMMARY...The potential for damaging gusts and a tornado or two
should be maximized over the next couple of hours across far
southeast IL into southern IN.
DISCUSSION...KVWX/KIND radars show a broken line of strong/severe
storms near the IL/IN border. Located near the intersection of a
low-level surface trough and warm front, convection has gradually
intensified over the last hour. Low-level rotation and supercell
structures have been observed, though the overall convective mode is
a mixture of cells and linear clusters. The environment downstream
remains supportive of strong/severe storms this evening with
damaging gusts the most likely hazard.
Low-level rotation has increased over the last 15 min with several
embedded mesocyclones. The KVWX VAD shows substantial veering in the
lowest 1-2km with 0-500m SRH above 250 m2/s2 near the front. This
and an STP of 1-2 will support the potential for a tornado or two
with any stronger supercell structures or QLCS segments as they
approach the frontal zone.
The loss of diurnal heating and storm motions will eventually move
convection into more stable air this evening. This suggests the
greatest severe threat is likely over the next couple of hours.
..Lyons/Smith.. 10/15/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ILN...LMK...IND...PAH...ILX...
LAT...LON 38528822 39168760 39328663 39298605 39158560 38938540
38628557 38428618 38298735 38288785 38188807 38528822
MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 PM CDT Thu Oct 15 2026
Valid 152000Z - 161200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
MIDWEST...
...SUMMARY...
Thunderstorms capable of severe wind gusts and a tornado or two are
possible today across parts of the middle Mississippi and Ohio
Valleys.
...20z Update...
A loosely organized cluster of storms has developed over southeast
Illinois, positioned on the northern periphery of modest instability
(MLCAPE near 1000 J/kg) that has developed where skies have remained
at least partially clear. Although persistent cloud cover has thus
far limited destabilization of the downstream environment, low-level
warm/moist air advection combined with some breaks in cloud cover
may promote further destabilization. Should this occur, ample
deep-layer shear of 40-45 kts should help to maintain convective
organization, with a few damaging wind gusts possible. Therefore, a
Slight Risk has been maintained, but trimmed to areas in/downstream
of the ongoing convective activity.
In addition, a minor expansion of the wind/tornado probabilities was
made, extending into portions of far southern Illinois and far
southwest Indiana where visible satellite indicates some cumulus
development amid the aforementioned area of instability. A few
isolated damaging wind gusts would be possible if isolated cells are
able to develop in this region.
Elsewhere, a few damaging wind gusts are possible this
afternoon/evening across portions of northwest Texas. See MCD #2378
for additional details.
..Karstens.. 10/15/2026
.PREV DISCUSSION... /ISSUED 1155 AM CDT Thu Oct 15 2026/
...Midwest/Ohio Valley...
Extreme/record-caliber seasonal moisture content exists over the
region with warm-sector prevalent 2+ inch Precipitable Water values
and surface dewpoints in excess of 70F. A surface wave over the
middle part of Missouri late this morning should gradually/modestly
deepen as it progresses east-northeastward near a northward-shifting
warm front, although the front/warm sector are a bit muddled by
ongoing convection across southern portions of Missouri and
Illinois.
Current split flow over the Great Plains will quickly resolve, with
a central Plains shortwave trough/speed max phasing with a
broader-scale upper trough over the Upper Midwest through tonight.
The net result will be a strengthening of deep-layer winds
along/north of the warm sector that will shift poleward, although to
what exact degree/spatial extent is uncertain given some of the
ongoing convection.
At least some scattering of warm-sector cloud cover, diurnal heating
and the increasing moisture content with northward extent will allow
for modest cool season destabilization, with SBCAPE potentially
exceeding 1000 J/kg across the lower Wabash Valley and
southern/downstate portions of Illinois and Indiana. This should
allow for re-development/intensification of storms this afternoon,
although the exact magnitude of today's severe risk is still a bit
uncertain and contingent on surface heating/destabilization. But
this scenario could include a few supercells, with the possibility
of a semi-focused severe/some tornado risk near the warm front,
which may be augmented by some of the prior convection, and ahead of
the surface low. Supercells aside, some semi-organized clusters
capable of wind damage should evolve within the high-moisture
content environment and 40+ kt effective shear. Overall storm
intensity is likely to wane within a couple hours of sunset,
generally by late evening.
...North/West Texas...
An outflow-augmented cold front will continue to spread
southeastward. The tendency for post-frontal convection should
remain the dominant scenario with boundary-parallel deep-layer flow
contributing to a more anafrontal character. Gradual diurnal heating
could support some intensification of storms along the leading edge
of the composite boundary this afternoon. As such, some stronger
wind gusts are plausible, but this scenario and related potential
for organized severe storms is currently expected to remain limited.
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0222 PM CDT Thu Oct 15 2026
Valid 161200Z - 171200Z
...CRITICAL FIRE WEATHER AREA FOR WESTERN L.A. COUNTY...VENTURA
COUNTY AND SOUTHEASTERN SANTA BARBARA COUNTY...
...Southern California...
An mid/upper low just west of the Baja Peninsula within a broader
upper-level ridge over the western U.S., combined with a 1038 mb
surface high pressure moving into the central U.S. will continue to
support dry, offshore flow across southern CA through D2/Friday. A
zone of sustained 20-30 mph winds and gusts up to 50 mph is still
expected across western L.A. county into Ventura and far
southeastern Santa Barbara Friday morning before slowly diminishing
Friday afternoon and evening. Despite RH trending higher through
Friday (closer to 20% daytime minimum across L.A./Ventura counties),
stronger winds and drying fuels will still present a Critical fire
weather threat. Elevated fire weather highlights stretch westward
towards the central CA coast owing to a reduced offshore wind
magnitude, although minimum RH values of 15% should be common.
...Sierra Nevada, Sacramento Valley into the North Bay area...
Residual easterly/northeasterly downslope winds of 10-15 mph
(locally 20 mph in channeled terrain) across the western slopes of
the Sierra Nevada are expected Friday. The combination of poor
overnight RH recoveries with minimum daytime RH near 10%, dry fuels
and breezy east-northeast winds supports addition of elevated
highlights across this region. Dry and breezy conditions including
north to northeast winds of 10-15 mph and RH falling ing into the
10-15% range in valley locations will affect portions of the
Sacramento Valley, Napa Valley and North Bay areas Friday where
Elevated highlights have been introduced.
...Lower Mississippi River Valley and ArkLaTex Region...
A dry, post-frontal air mass will push into the Deep South beginning
D2/Friday. Northerly winds of 10-15 mph with higher gusts amid RH
reductions as low as 25% will promote elevated fire weather
conditions over receptive fuels across portions of the Lower
Mississippi River Valley and ArkLaTex Region. Elevated highlights
were expanded slightly eastward to include central MS accounting for
latest model guidance consensus and generally drier fuelscape where
ERCs reach into the 80-90th percentile range.
..Williams.. 10/15/2026
.PREV DISCUSSION... /ISSUED 0108 AM CDT Thu Oct 15 2026/
...Synopsis...
An amplified upper trough will progress over the eastern CONUS as a
surface low departs from New England. A substantial cold front will
sweep across the southeastern CONUS on Day 2/Friday, with dry
post-frontal flow bringing fire weather concerns to portions of the
lower MS River Valley. High pressure building in behind the cold
front along with a mid-level cutoff low over the Baja Peninsula will
continue to support offshore flow and a fire weather threat across
portions of CA.
...Southern California...
An offshore wind event will continue through Day 2/Friday across
much of southern CA, maintaining an Elevated fire weather threat. A
mid/upper cut-off low over the Baja Peninsula will aid in deep layer
easterly flow over the region, supporting surface winds of 20-30 mph
(gusts up to 40 mph in the valleys, possibly up to 60 mph in the
mountains) amid 10-15% RH. The long duration of these conditions
combined with poor overnight humidity recoveries will allow fuels to
become increasingly more receptive. Easterly winds will increase to
15-25 mph across the southern Sierra Nevada foothills into the lower
San Joaquin Valley amid minimum RH values of 15-20%.
The offshore pressure gradient will strengthen early in the forecast
period, likely at its final peak before gradually weakening into Day
3/Saturday. A corridor of sustained 20-30 mph winds and gusts up to
50 mph are expected across western L.A. county into Ventura and far
southeastern Santa Barbara county during the early morning hours of
Day 2/Friday, supporting the introduction of Critical highlights.
...Lower Mississippi River Valley and ArkLaTex Region...
A dry, post-frontal northerly wind will impact much of the Southeast
as surface high pressure builds into central Plains/Midwest. Dry and
receptive fuels remain across the lower Mississippi Valley where
drought proliferates, with ERC values ranging from the 80-90th
percentiles. Northerly sustained winds of 10-15 mph (perhaps up to
20 mph in localized areas) and RH as low as 25% will promote an
Elevated fire weather threat for a few afternoon hours.
...Please see www.spc.noaa.gov/fire for graphic product...
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0409 PM CDT Thu Oct 15 2026
Valid 171200Z - 231200Z
...Synopsis...
Offshore winds aided by a mid/upper low west of Baja California and
surface high pressure across the central U.S. will continue into at
least the morning hours of D3/Saturday across portions of southern
CA. Northerly flow within a dry, post-frontal air mass will likely
bring a fire weather threat to the lower MS River Valley region
D3/Saturday. Potential for significant fire weather diminishes
D4/Sunday across CONUS as offshore winds decrease across southern CA
with weakening winds over the lower MS River valley as high pressure
shifts towards the Mid Atlantic. Mid-range guidance suggests a
stronger upper-level trough moving into the western U.S. early next
week bringing a period of dry and breezy conditions to northeastern
CA and adjacent northwestern Great Basin.
...Day 3/Saturday...
...Southern California...
Residual offshore easterly flow will continue through the morning
hours across portions of southern CA Saturday. East to northeast
winds of 10-20 mph and low RH will sustain the ongoing fire weather
threat through Saturday morning before lighter winds emerge by
Saturday afternoon and evening. A 40% critical probability area
continues for the Simi Valley area as well as the Sierra Madre and
San Rafael ranges.
...Lower Mississippi River Valley...
Fire weather concerns will shift southward from the ArkLaTex region
into the lower MS River Valley by Saturday under a dry, post-frontal
pattern. A consistent north-northeast wind of 10-15 mph along with
minimum daytime RH values near 25% are expected where fuels will be
quite receptive, including along the Gulf Coast of LA. Only a minor
north and eastward expansion of the 40% critical probability area
was needed.
...Day 5/Monday...
...Northeastern California and Northwest Great Basin...
A robust mid/upper trough could bring increasing southwesterly flow
back into the western U.S. by early next week. Dry and breezy
conditions in advance of the trough will promote an increasing fire
weather threat over northeastern CA, far southern OR and far
northwestern NV D5/Monday where fuels remain dry in the absence of
recent precipitation. Thus, 40% critical probabilities have been
added to highlight the potential for fire weather impacts.
..Williams.. 10/15/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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