RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Sat Apr 18 12:44:02 UTC 2026.
MD 0490 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWEST INTO NORTH-CENTRAL TX
Mesoscale Discussion 0490
NWS Storm Prediction Center Norman OK
0620 AM CDT Sat Apr 18 2026
Areas affected...Southwest into north-central TX
Concerning...Severe potential...Watch unlikely
Valid 181120Z - 181345Z
Probability of Watch Issuance...5 percent
SUMMARY...Isolated hail and localized strong to severe gusts are
possible this morning.
DISCUSSION...Some increase in storm coverage and intensity has
recently been noted across parts of the TX Concho Valley and Big
Country, to the north of a southward-moving cold front. Elevated
convection is expected to continue moving east-northeastward to the
north of the boundary through the morning, as the favored storm
corridor gradually shifts southward with time in conjunction with
the front. MUCAPE of greater than 1000 J/kg will continue to favor
occasional robust updrafts. Rather strong mid/upper-level
southwesterly flow will support sufficient effective shear for at
least transient storm organization, and an elevated supercell or two
cannot be ruled out.
The favorable buoyancy and shear will result in potential for
isolated hail with the strongest cells. While convection will remain
elevated, strong to localized severe gusts may also occur, in
association with gravity-wave-related processes within the
post-frontal regime. At this time, the severe threat appears too
marginal and isolated for watch issuance.
..Dean/Smith.. 04/18/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...EWX...SJT...MAF...
LAT...LON 31050220 32409988 33069782 33219701 33169627 31639618
30569904 30160099 30070198 30210217 30640230 31050220
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
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SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0732 AM CDT Sat Apr 18 2026
Valid 181300Z - 191200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
UPPER OHIO VALLEY TO THE APPALACHIANS...
...SUMMARY...
Scattered strong to severe thunderstorms capable mainly of damaging
winds will be possible today across the upper Ohio Valley and
central Appalachians.
...Synopsis...
Water-vapor imagery this morning shows a large-scale upper trough
over the Upper Midwest into the south-central Plains. An elongated
mid-level vorticity lobe and associated speed max will quickly move
eastward across the Midwest today and reach the Lower Great Lakes
and upper OH Valley late tonight. Farther south, a belt of strong
west-southwesterly flow associated with a subtropical jet will
reside over TX.
A cold front extending from a low near James Bay southward through
the Great Lakes and into TX will continue to push east and southeast
through the period. Convective outflow over the OH Valley to the
east of the front will eventually be overtaken by the front later
today as a band of showers/thunderstorms develops over the upper OH
Valley by early afternoon.
...OH Valley into the Appalachians...
Some heating combined with a gradually moistening airmass (55-60 deg
F surface dewpoints) will result in weak destabilization by midday
as convective development ensues near the preceding outflow/wind
shift and front. Ample mid to high-level flow will aid in some
potential for storm organization, mainly in the form of a few
stronger cells and linear bands. Widely scattered strong to severe
gusts capable of wind damage will likely be the primary hazard, but
an isolated risk for hail or a brief tornado is possible with the
strongest cells. This activity will likely weaken by early evening
as it encounters a slightly drier and less unstable airmass with
east extent.
...Central Texas...
Scattered showers and elevated thunderstorms are expected throughout
much of the day as the cold front rapidly undercuts a moist and
unstable air mass. The 12 UTC Del Rio, TX raob shows an 8.2 deg
C/km 700-500 mb lapse rate. Forecast soundings show MUCAPE parcels
rooted in the 850-700 mb layer, with effective deep-layer shear of
50-60 kt. Although an isolated risk for large hail appears to be
the main hazard with the stronger cells, there has been some
indication that a localized risk for severe gusts could accompany
the strongest cores. For short-term details regarding a risk for
hail/wind with a few stronger thunderstorms this morning extending
from the Concho Valley east-northeast towards DFW, reference MCD
#490.
..Smith/Dean.. 04/18/2026
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