U.S. Severe Weather Forecast (Convective Outlook)

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000 
acus01 kwns 270054 
swody1 
Storm Prediction Center ac 270052 


Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0752 PM CDT Tuesday Jul 26 2016 


Valid 270100z - 271200z 


..there is a slight risk of severe thunderstorms across parts of the central/northern 
High Plains... 


..there is a marginal risk of severe thunderstorms from the Central High plains to 
the upper Great Lakes... 


..there is a marginal risk of severe thunderstorms across the middle Atlantic... 


... 
thunderstorms may produce severe gusts and large hail this evening 
over parts of western and central Nebraska and South Dakota. 


..northern/Central Plains... 


Weak short-wave trough has topped the western US ridge and is digging 
southeastward across the Black Hills region. Strong convection has developed 
ahead of this feature and multiple supercells are now merging over 
northern portions of ww417. Mrms data suggests very large hail has been 
noted with several of these updrafts but storm mergers should lead 
to at least one mesoscale convective system this evening as low level jet increases over the Central 
Plains. 


Farther north...isolated strong storms will linger from southeastern ND into 
central Minnesota for several hours before gradually weakening with loss of 
daytime heating. 


..middle Atlantic... 


Remnant mesoscale convective vortex from old convection has progressed into northern WV. This 
feature appears to be partly responsible for scattered convection that 
developed across the central Appalachians. Downstream...several storm 
mergers are ongoing across central Virginia...aided in part by convective 
outflow interactions. This activity should begin to weaken with 
loss of daytime heating. Until then...marginally severe hail and 
gusty winds can be expected. 


.Darrow.. 07/27/2016 


$$ 

Mesoscale Discussion


999 
acus11 kwns 262233 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 262232 
sdz000-nez000-wyz000-270030- 


Mesoscale discussion 1402 
National Weather Service Storm Prediction Center Norman OK 
0532 PM CDT Tuesday Jul 26 2016 


Areas affected...portions of far eastern Wyoming...southern South Dakota...and northern/western Nebraska 


Concerning...severe potential...watch possible 


Valid 262232z - 270030z 


Probability of watch issuance...40 percent 


Summary...an isolated large hail and damaging wind threat should 
increase over the next several hours. Ww issuance is possible. 


Discussion...convection has recently developed/intensified across 
the Black Hills in South Dakota...and across an outflow boundary across southern 
South Dakota. Additional convective development has occurred along a Lee 
trough over the Central High plains extending southward from a surface low over 
western Nebraska. A relatively narrow corridor of better low-level moisture 
extends northward from western Kansas into northern/central Nebraska and southern South Dakota...and this 
moisture combined with steep middle-level lapse rates is supporting 
MLCAPE of generally 1500-2500 j/kg. Large-scale ascent remains weak 
across the mesoscale discussion area...but a minor perturbation evident on water 
vapor satellite imagery over eastern Montana/Wyoming within zonal flow across the 
northern Continental U.S. Should support maintenance of ongoing convection for at 
least the next several hours. Middle-level flow remains around 30 
knots...but a strongly veering wind profile is supporting effective 
bulk shear values of 35-45 knots. A mix of supercell/multicell clusters 
with an isolated large hail/damaging wind threat appears probable 
initially...with some potential growth into one or more bowing line 
segments possible. 


.Gleason/Thompson.. 07/26/2016 


..please see www.Spc.NOAA.Gov for graphic product... 


Attention...WFO...fsd...abr...lbf...unr...cys... 


Latitude...Lon 42189961 41950082 42970453 43860453 44520413 44490112 
44129923 43669839 43029857 42189961