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
ACUS48 KWNS 280856
SPC AC 280855

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0355 AM CDT Wed Jun 28 2017

Valid 011200Z - 061200Z

An upper trough will move eastward across the Great Lakes and the
Northeast on D4/Sat with 30-40 kt midlevel flow overspreading a
moist air mass. A surface low will exist over southwestern Quebec,
with a weak front nearing the lower Great Lakes and extending into
the mid MS Valley by 00Z Sunday. Instability will be relatively
weak, but widespread rain and thunderstorms may result in a few
marginally severe wind gusts. Given the low-end nature of this
event, will defer a possible slight risk for wind to later updates
when predictability increases.

By D5, the front over the Northeast will have cleared the coast, but
a marginal wind threat may exist into the Mid Atlantic where the
front may stall. Here, it will be very moist, with modest CAPE
values and weak westerly flow aloft.

To the west, several models insist on a weak shortwave trough within
a northwest flow regime crossing the Rockies and entering the
central and northern High Plains on D5/Sun afternoon. Southerly
low-level flow will bring 60s F dewpoints northward toward this
wave, with a weak surface low over western KS or eastern CO. An
associated weak cold front, as well as a nocturnal low-level jet
will likely drive development, but predictability is low for where
any MCS might track. Beyond D5, the aforementioned shortwave trough
looks to weaken with time as it continues into the MS and OH

..Jewell.. 06/28/2017 is the U.S. government's official web portal to all federal, state and local government web resources and services.