SPC AC 180034
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0734 PM CDT Thu Apr 17 2025
Valid 180100Z - 181200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EXTREME
EASTERN NEBRASKA INTO WESTERN AND CENTRAL IOWA...
...SUMMARY...
Isolated to scattered severe thunderstorms will continue early
tonight from eastern Nebraska into western and central Iowa. Very
large hail to 3 inches in diameter or greater, isolated severe gusts
of 60-70 mph, and a couple of tornadoes will all be possible.
...01z Update...
Water-vapor imagery suggests a weak short-wave trough is located
over western NE, extending into northwest KS. Later tonight an 80kt
500mb speed max will translate across KS toward southeast NE, and
this will encourage a marked increase in the LLJ across KS into
northwest MO by 06z. Latest radar data depicts isolated-scattered
severe supercells near the MO River from eastern NE into western IA.
This activity will spread east, aided in part by the aforementioned
LLJ. With time, storm inflow will gradually lift as the boundary
layer decouples, and storms will become more elevated. For the next
few hours very large hail remains possible, along with a risk for
tornadoes, and wind. As the storms become elevated hail will become
the most likely concern.
..Darrow.. 04/18/2025
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
SPC AC 171730
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Thu Apr 17 2025
Valid 181200Z - 191200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
SOUTHERN PLAINS NORTHEASTWARD TOWARD THE UPPER GREAT LAKES...
...SUMMARY...
Scattered severe thunderstorms are possible from parts of the
southern Plains northeastward toward the upper Great Lakes from late
Friday afternoon into early Saturday morning. Large hail and
isolated severe gusts will be the main hazards.
...Synopsis...
A broad belt of strong southwest winds aloft will stretch from Baja
CA to the Great Lakes, with an upper trough extending from Manitoba
into the Great Basin. Meanwhile, upper ridging will occur over the
eastern states, with a high over the Gulf Of America.
At the surface, a large area of high pressure will exist over the
east, with southeast flow around the high bringing moisture off the
Gulf and into southern Plains and Midwest. This moistening will
occur ahead of a cold front, stretching roughly from southern WI
into central MO and OK at 00Z. This front will gradually progress
south and east, and will be the primary focus for scattered severe
storms on Friday.
...Lower MO Valley into OK and TX...
Strong surface heating will occur over TX and into western OK Friday
afternoon, as mid 60s F dewpoints surge northward toward the
approaching cold front. This front will be near I-40 at 00Z, with
clusters of severe storms likely developing in the heated air from
western OK into northwest TX. MLCAPE over 2500 J/kg is possible, and
wind profiles south of the cold front will favor supercells. Initial
development may produce a couple tornadoes prior to the cold front
undercutting the storms as they progress east/northeastward across
OK. Very large hail will be possible on both side of the front as
hodographs will be elongated and primarily front-parallel.
Farther northeast into KS and MO, additional lift via warm advection
late in the day and into the evening will also support clusters of
severe storms, possibly elevated but also with hail and localized
wind potential.
...Upper Great Lakes southward into the mid MO Valley...
Strong warm advection will result in elevated thunderstorms by
midday over parts of WI and into northern/Upper MI, with sufficient
instability to support an elevated marginal hail risk. Farther
south, late afternoon development is likely along the front from
southern WI to the IA/IL border area and into MO, aided by daytime
heating. Though capped, lift along the boundary should instigate
scattered cells near 00Z, with isolated supercells tracking across
IL, IN, and perhaps southern MI and northwest OH. Winds just off the
surface will be quite strong at over 50 kt, aiding wind gusts. A
brief tornado cannot be ruled out across this region, and scattered
hail is likely as well.
..Jewell.. 04/17/2025
WUUS02 PTSDY2
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z
SPC AC 171907
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0207 PM CDT Thu Apr 17 2025
Valid 191200Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
SOUTHERN PLAINS TOWARD THE OZARKS...
...SUMMARY...
Scattered strong to severe thunderstorms are possible from central
Texas into the Ohio Valley on Saturday.
...Synopsis...
An upper trough will move eastward across Ontario and Quebec,
deepening all the while. Meanwhile, a southern-stream low/trough
will move from AZ/NM into the southern Plains. This system will take
on a negative tilt into Sunday morning.
At the surface, a front will stall from PA westward to the middle MS
Valley, and southwestward into northwest TX. Upper 50s F to lower
60s F dewpoints will be common along and south of this boundary,
with the most substantial instability developing from west-central
TX into OK. Winds around 850 mb will initially be out of the
southwest across the entire warm sector, but backing and
strengthening will occur over the southern Plains late as the upper
trough approaches. At that time, a cold front will further increase
lift over TX and OK.
...From parts of OK across MO/IL/IN/OH/PA...
Substantial rain and thunderstorms are likely to be ongoing early on
Saturday north of the stationary front and aided by theta-e
advection just off the surface with 30+ kt southwest 850 mb winds.
While the low-level lapse rates will initially be poor, sufficient
elevated instability combined with strong deep-layer shear may
support marginal hail during the day. Indications are that heating
will be most prominent from the central Appalachians into parts of
the upper OH Valley and into PA, and a few diurnally driven cells
may produce marginal hail over OH and PA.
...TX/OK into the Ozarks...
Scattered storms may redevelop from northern TX into OK during the
day, as low-level moisture advection is maintained across the warm
sector and north of the boundary. Lapse rates will likely be poor
due to extensive clouds and persistent showers/storms.
Later in the day, strong heating over southwest TX and lift near the
cold front should allow for new development over west-central TX
during the late afternoon, with increasing storm coverage as the
low-level jet increases through the night. A few supercells may
develop in this region, producing large hail. The front may tend to
undercut the activity, but a brief tornado cannot be ruled out.
Farther north, batches of elevated storms will spread out of TX and
into OK, with both periodic hail and heavy rain threat (see WPC Day
3 Excessive Rainfall Product).
..Jewell.. 04/17/2025
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z
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