Severe Storm Outlook Narrative (AC)
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
000
ACUS01 KWNS 260547
SWODY1
SPC AC 260546

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1246 AM CDT Fri May 26 2017

Valid 261200Z - 271200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE HIGH
PLAINS FROM CO TO THE EASTERN OK PANHANDLE...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN HIGH PLAINS TO IL/IN...

...SUMMARY...
Scattered severe thunderstorms are expected across the central
Plains with isolated activity into the eastern Texas Panhandle.  A
few strong storms may also be noted across parts of the middle
Mississippi Valley and Ohio Valley region.

...Plains...

Large-scale height rises are expected across most of the contiguous
US Friday, though large-scale troughing will hold across the Western
States.  Early-morning water-vapor imagery suggests a couple of weak
disturbances across the inter-mountain region and one notable
short-wave trough is observed over the northern Baja Peninsula.  In
the absence of significant large-scale forcing for ascent, it
appears diurnal heating and orographic influences will prove
instrumental in convective development across the High Plains.

Latest short-range model guidance suggests strong boundary-layer
heating will be observed across the High Plains such that surface
parcels should reach their convective temperatures near 22z.
Scattered convection is expected to develop across eastern CO within
favorable southeasterly upslope flow.  Isolated storms are also
expected to evolve along the dryline into the eastern TX Panhandle,
possibly aided by aforementioned Baja short wave.  CINH should be
negligible across these regions by late afternoon and deep-layer
shear is more than adequate for supercell development.  Several
high-res models agree with this scenario and large hail and damaging
winds can be expected with these storms.  Organized severe threat
will struggle to reach central KS/south-central NE until after
midnight.  Even so, activity should be waning by this time.

...Mid MS Valley/OH Valley...

Early-morning radar data exhibits a long-lived convective cluster
moving into northeast KS.  Remnants of this convection may influence
daytime convection downstream across the mid MS and OH valley.  00z
model guidance is not particularly helpful regarding a convective
scenario later today across this region.  Significant capping is
observed across the southern Plains and this warm pocket of air at
700mb will spread across AR/southern MO by midday toward southern
IL.  Convection should struggle to develop at these lower latitudes
despite several model solutions suggesting otherwise.  With nebulous
forcing and broad height rising expected it appears diurnal heating
and weak warm advection atop the boundary layer could aid
thunderstorm risk.  Otherwise, remnant convective cluster over KS
could enhance storm development over IL/IN later in the day.

..Darrow/Dean.. 05/26/2017

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.