Severe Storm Outlook Narrative (AC)
Issued by NWS
ACUS11 KWNS 200450
SPC MCD 200450
Mesoscale Discussion 0298
NWS Storm Prediction Center Norman OK
1150 PM CDT Sun Mar 19 2017
Areas affected...Eastern Iowa and northwestern Illinois
Concerning...Severe potential...Watch unlikely
Valid 200450Z - 200615Z
Probability of Watch Issuance...5 percent
SUMMARY...Elevated thunderstorms across eastern Iowa and
northwestern Illinois will pose a risk for marginally severe hail.
A severe thunderstorm watch will not be necessary.
DISCUSSION...Elevated convection is beginning to develop across
eastern IA in a zone of enhanced low-level warm advection, on the
nose of a 50 kt southwesterly low-level jet. Midlevel lapse rates
of 8-9 C/km and an upstream reservoir of buoyancy (MUCAPE of
1000-1500 J/kg) across southern IA will support a few strong
updrafts within the broader bands of elevated storms. The stronger
storms may produce marginally severe hail over the next few hours as
convection spreads from IA into IL as the low-level jet veers to a
more westerly direction.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 42048911 41638844 41178852 40968911 41239105 41599246
41929273 42189263 42269219 42319069 42048911