- Day Three
acus01 kwns 241630
Storm Prediction Center ac 241628
Day 1 convective outlook
National Weather Service Storm Prediction Center Norman OK
1128 am CDT sun Jul 24 2016
Valid 241630z - 251200z
..there is a slight risk of severe thunderstorms over northestern Illinois/extreme southeastern
WI/southwestern lower Michigan and northern Indiana...
..there is a slight risk of severe thunderstorms over eastern Colorado...
..There is a marginal risk of severe thunderstorms from the Great Lakes into the
..there is a marginal risk of severe thunderstorms over central/southern Florida...
severe thunderstorms capable of producing damaging wind gusts and
large hail will be possible over parts of eastern Colorado...and
over parts of northeast Illinois...extreme southeast
Wisconsin...southwest lower Michigan and northern Indiana...mainly
during the later afternoon and evening. Isolated severe storms will
be possible across the Great Lakes and Midwest regions...and over
the central and southern Florida Peninsula.
..northeast Illinois/extreme southeastern WI/southwestern lower Michigan and northern Indiana...
Ongoing storms over lower Michigan have generated a composite outflow
boundary extending from northwestern Ohio and northern Indiana into Southern Lake Michigan.
Widespread cloud cover to the north of this boundary is expected to
limit diabatic heating and strengthen the thermal gradient along the
composite warm front/outflow boundary. To the S/SW of this
boundary...strong heating and diurnal destabilization will occur
within an environment characterized by ample moisture with surface
dew points in the upper 70s...resulting in MLCAPE of 2500-4000 j/kg
likely this afternoon.
Although large scale ascent associated with the upper trough
translating eastward over northern Minnesota and Lake Superior will remain north of
this area...weak low-level convergence along an approaching cold
front...potentially enhanced near a projected outflow boundary/front
intersection...may be sufficient to initiate widely scattered
thunderstorms over this region during the late afternoon and evening
hours. Modest vertical shear will promote a few organized multicell
clusters with potential for damaging wind gusts and large hail to
Moist upslope low-level flow will become better established across
the area this afternoon as strong heating occurs over the mountains
and plains...with surface dew points remaining in the 50s especially
across the plains. Steep middle-level lapse rates will contribute to
moderate instability with MLCAPE of 1000-2000 j/kg developing this
afternoon. Model consensus indicates storms will develop near the
Front Range by middle-afternoon with activity spreading eastward across the
plains through the evening. Strong directional shear with height
will enhance storm organization with more intense storms capable of
producing large hail and strong wind gusts.
As an upper low moves westward across the southern peninsula...thunderstorms
are expected to continue developing over the central/southern parts of
the state. Relatively cool middle-level temperatures are enhancing
lapse rates with potential for isolated strong/severe storms this
afternoon and evening. See mesoscale discussion 1385 for more detailed information.
..parts of northern/eastern Ohio into western PA...
Satellite/radar animations suggest presence of an mesoscale convective vortex over Northern Ohio
that is moving slowly eastward. A few stronger storms are associated
with the mesoscale convective vortex at this time...and convective development may be
enhanced downstream from the mesoscale convective vortex into this evening. For this
reason...have extended the marginal risk area farther east/southeast across
eastern Ohio into western PA where storms capable of producing gusty winds and
marginally severe hail may occur.
acus11 kwns 241703
sels mesoscale discussion
Storm Prediction Center mesoscale discussion 241703
Mesoscale discussion 1386
National Weather Service Storm Prediction Center Norman OK
1203 PM CDT sun Jul 24 2016
Areas affected...portions of northern/eastern Ohio...western PA...the northern WV
Concerning...severe potential...watch unlikely
Valid 241703z - 241930z
Probability of watch issuance...5 percent
Summary...thunderstorms will continue to increase in number/intensity
through the afternoon across parts of the upper Ohio Valley and
vicinity. Locally strong thunderstorms -- some possibly approaching severe
limits -- may occur...though ww issuance is not anticipated.
Discussion...visible satellite loops and surface observations indicate a
warm front advancing northeastward across parts of western PA and northestern Ohio...with
dewpoints into the upper 60s/around 70f on the warmer side of this
boundary. Broad cumulus fields SW of the warm front highlight the
moist/destabilizing boundary layer.
With little capping...and given forcing for ascent related to an mesoscale convective vortex
moving eastward across the Cleveland area...a surface boundary moving southward
across parts of northwestern/N-cntrl Ohio...differential-heating-induced
baroclinicity on the edge of multi-layered clouds across Northern Ohio --
thunderstorms should continue increasing in coverage/intensity this
afternoon. This activity will spread generally ewd/esewd.
With moderately unstable air characterized by MLCAPE around
1500-2000 j/kg continuing to build northeastward across the upper Ohio
Valley...a few vigorous updrafts may evolve. The cle vwp suggests
only around 20 knots of 0-6-km bulk shear present...though a few
multicell clusters with locally damaging wind gusts could occur.
Generally poor middle-level lapse rates and the lack of stronger deep
shear should prevent a more substantial severe risk from evolving.
..please see www.Spc.NOAA.Gov for graphic product...
Latitude...Lon 40098064 40228191 40688315 41058336 41178292 41068169
41328055 40967941 40267973 40098064