RSS Mesoscale Discussions from Storm Prediction Center
WW 516 SEVERE TSTM IL IN KY 262210Z - 270500Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 516
NWS Storm Prediction Center Norman OK
510 PM CDT Sun Jul 26 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Southern Illinois
Southwest Indiana
Western into Central Kentucky
* Effective this Sunday afternoon from 510 PM until Midnight CDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph likely
Isolated very large hail events to 2 inches in diameter possible
A tornado or two possible
SUMMARY...Widely scattered thunderstorms are forecast to continue to
develop and intensify through the early and mid evening. A couple
of the stronger storms will probably acquire supercell structure and
pose a risk for large hail, damaging gusts, and perhaps a tornado
through the early evening. As additional storms develop and outflow
becomes more prevalent, strong to severe gusts (55 to 70 mph)
capable of wind damage will become the primary severe hazard towards
the mid to late evening.
The severe thunderstorm watch area is approximately along and 60
statute miles east and west of a line from 50 miles northeast of
Salem IL to 30 miles southwest of Bowling Green KY. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU6).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
33025.
...Smith
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WW 0516 Status Updates
STATUS REPORT ON WW 516
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 ENE MDH
TO 35 WSW EVV TO 25 WSW OWB TO 5 S OWB TO 45 W SDF TO 35 W SDF.
..SQUITIERI..07/27/26
ATTN...WFO...ILX...PAH...LSX...IND...LMK...
STATUS REPORT FOR WS 516
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
ILC059-069-087-127-151-165-199-270140-
IL
. ILLINOIS COUNTIES INCLUDED ARE
GALLATIN HARDIN JOHNSON
MASSAC POPE SALINE
WILLIAMSON
KYC003-009-027-031-033-035-047-055-059-061-083-085-091-107-139-
141-143-145-149-157-171-177-183-213-219-221-225-227-233-
270140-
KY
. KENTUCKY COUNTIES INCLUDED ARE
ALLEN BARREN BRECKINRIDGE
BUTLER CALDWELL CALLOWAY
CHRISTIAN CRITTENDEN DAVIESS
EDMONSON GRAVES GRAYSON
HANCOCK HOPKINS LIVINGSTON
LOGAN LYON MCCRACKEN
MCLEAN MARSHALL MONROE
MUHLENBERG OHIO SIMPSON
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MD 1750 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF VA/MD INTO WESTERN/CENTRAL NC
Mesoscale Discussion 1750
NWS Storm Prediction Center Norman OK
0804 PM CDT Sun Jul 26 2026
Areas affected...Parts of VA/MD into western/central NC
Concerning...Severe potential...Watch unlikely
Valid 270104Z - 270300Z
Probability of Watch Issuance...20 percent
SUMMARY...Strong to locally severe storms will be possible through
the evening.
DISCUSSION...Isolated strong storms across VA have gradually
intensified this evening, with short-term guidance suggesting a
continued increase in storm coverage with time. While thermodynamic
profiles are not particularly favorable (with weak lapse rates and
rather cool surface temperatures), seasonably strong northwesterly
mid/upper-level flow (as noted on the 00Z RNK sounding) associated
with a mid/upper trough over the eastern CONUS will provide
sufficient deep-layer shear for organized storm structures.
Relatively organized multicells and perhaps a couple of marginal
supercells may evolve with time across the region. With marginal
thermodynamic profiles and the onset of nocturnal cooling, storms
may struggle to achieve severe intensity. However, any organized
cells or clusters could pose a threat of locally damaging wind
through the evening, while a brief tornado and small to near-severe
hail cannot be ruled out with any persistent supercell.
..Dean/Smith.. 07/27/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...AKQ...LWX...RAH...RNK...GSP...
LAT...LON 35738124 38047892 39277781 39317720 39077660 38627639
37587704 36067843 35487938 35357980 35348040 35438095
35738124
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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MD 1749 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF WESTERN INTO MIDDLE TENNESSEE
Mesoscale Discussion 1749
NWS Storm Prediction Center Norman OK
0734 PM CDT Sun Jul 26 2026
Areas affected...portions of western into middle Tennessee
Concerning...Severe potential...Watch possible
Valid 270034Z - 270130Z
Probability of Watch Issuance...60 percent
SUMMARY...Damaging gusts, a few of which may be severe, are expected
to accompany an approaching MCS. If the MCS maintains intensity
while approaching the KY/TN border over the next hour or so, a WW
issuance may be needed.
DISCUSSION...A cold-pool-driven MCS, with a history of wind damage,
continues propagate south-southeast at approximately 40 kts. It is
plausible that this MCS will maintain intensity given the
combination of 4500+ J/kg MLCAPE and 35-40 kts of effective bulk
shear (oriented perpendicular to the leading line) preceding the
cluster. Assuming this remains the case, the MCS is poised to enter
TN by around 0130Z. A Severe Thunderstorm Watch issuance may be
needed beforehand to address the impending severe threat if this MCS
maintains its current intensity.
..Squitieri/Smith.. 07/27/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OHX...HUN...PAH...MEG...
LAT...LON 36168899 36408859 36538818 36638744 36628666 36388650
35848638 35348647 35138662 35028682 35038759 35068816
35098839 35208867 36168899
MOST PROBABLE PEAK WIND GUST...55-70 MPH
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SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0802 PM CDT Sun Jul 26 2026
Valid 270100Z - 271200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
UPPER MIDWEST AND WESTERN GREAT LAKES...
...SUMMARY...
Severe thunderstorms capable of large to very large hail, damaging
winds (possibly 75+ mph), and tornado risk remain likely from the
upper Mississippi Valley and Great Lakes southwestward into
Nebraska, mainly late this evening and tonight.
...Upper Midwest...
A very unstable environment remains in place across the region, with
the MPX, GRB, and DVN 00Z soundings sampling MLCAPE from 3100, 2900,
and 2800 J/kg, respectively. Surface observations show mid to upper
70s dewpoints on the warm side of the warm front extending from
north-central MN through northeast WI/far western Upper MI. A
thunderstorm has matured upstream of this corridor, with the
expectation it will remain strong to severe as it continues
southeastward. Modest low-level warm advection into this boundary
will also contribute to additional thunderstorms this evening and
overnight. Environmental conditions are still expected to support
large to very large hail early in the convective cycle while a more
cellular mode is likely. Thereafter, a trend towards bowing segments
capable of severe wind gusts is anticipated. A singular MCS could
eventually develop, with severe gusts possible as it moves southward
as well. Some gusts, both within the line segments and early in the
MCS lifecycle, could be significant (i.e. over 75 mph).
...TN Valley...
A cold-pool-driven MCS continues to propagate south-southeast at
approximately 40 kts. The downstream airmass is very moist, with
numerous sites reporting dewpoints in the low 80s. This moisture is
contributing to extreme buoyancy, with the recent 00Z BNA sounding
sampling 4500 J/kg of SBCAPE. This MCS is also oriented
perpendicular to the deep-layer vertical shear. All of these factors
will contribute to continued southward progression, with an
attendant risk for strong gusts likely extending into Middle TN this
evening.
...South-Central into Southeast SD into central NE...
Numerous attempts at deep convection along the weak surface trough
extending from south-central SD through central NE have failed thus
far. The window of opportunity for deep convection will likely
remain open for the next hour or two before building inhibition
associated with nocturnal cooling precludes mature convection. Until
that occurs, there remains a conditional risk for severe
thunderstorms capable of strong downdrafts and isolated large hail.
...Elsewhere...
Increasing thunderstorm coverage is possible across the Mid-Atlantic
over the next few hours as a shortwave trough progresses
southeastward across the region. Moderate vertical shear could
support updraft organization with deeper, more persistent
convection. Isolated damaging gusts and hail are possible with the
more organized storms. Isolated damaging gusts remain possible
across northern Wyoming and far southwest South Dakota as high-based
thunderstorms track northeastward across the region this evening.
Jackson Hole Wyoming reported a gust of 50 kt at 2353Z.
..Mosier.. 07/27/2026
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SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0437 PM CDT Sun Jul 26 2026
Valid 281200Z - 031200Z
Upper-level troughing is forecast across portions of the Pacific
Northwest through much of the workweek, with the main upper-level
low remaining offshore. Meanwhile, periodic mid-level shortwaves
will rotate through the base of the trough and over the area in the
southwest flow aloft. The strongest and most well-defined shortwave
is forecast Day 5/Thursday. Upper-level ridging across the southern
High Plains Day 3/Tuesday is expected to gradually build westward
into next weekend. Thereafter, longer-range ensemble guidance
continues to suggest that the aforementioned upper-level low may
move onshore next weekend, though timing details remain uncertain.
...Northwestern US...
Weaker flow aloft will tend to limit the fire weather threat across
the Pacific Northwest through much of the week. Though, locally
elevated fire weather conditions appear likely most days due to
lingering dry and breezy conditions amidst receptive fuels. While,
thunderstorm chances may return Day 5/Thursday as the aforementioned
shortwave trough impinges on the area, confidence in 10% coverage
remains a bit too low to introduce probabilities at this time.
Nevertheless, this will be monitored considering the forecast
sensitivities with multiple large fires ongoing across the area.
Longer range guidance continues to suggest dry and breezy conditions
may return to the Northwest sometime next weekend as the offshore
trough moves inland. At this time, confidence remains too low to
introduce Critical probabilities.
...Southern High Plains...
Hot, dry, and breezy conditions are likely across portions of the
southern High Plains through much of the workweek. While near
elevated fire weather conditions appear likely, recent fuel guidance
suggests the fuelscape remains mostly mixed and winds are forecast
to generally remain at or below elevated thresholds. Nevertheless,
fuels are expected to continue drying due to the multiple days of
hot, dry, and breezy conditions, which may necessitate fire weather
highlights in later forecasts.
..Elliott.. 07/26/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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