SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0240 PM CDT Fri Jun 17 2022
Valid 172000Z - 181200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN
VA AND NORTHERN NC...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
MT AND NORTHEAST WY...
...SUMMARY...
Scattered damaging wind swaths are expected through about sunset
across the central/southern Appalachians to the South/Lower-Mid
Atlantic Coast. Isolated significant severe wind gusts are possible
across a portion of eastern Montana and northeast Wyoming centered
on early evening. Isolated significant severe hail is possible
across northwest Montana through tonight.
...20z Update...
The main changes to the 20z outlook have been to trim behind ongoing
convection from the South to the Mid-Atlantic and New England coast
areas. The overall forecast philosophy remains unchanged from the
prior outlook, with a swath of damaging wind possible across parts
of northern GA into the Carolinas/Virginia through this evening.
A small southward adjustment into north-central CO has been made to
the Marginal risk area. Strong storms have been noted over higher
terrain in Boulder County. This activity is within a similar
environment to that further north, and may produce gusty winds and
marginally severe hail as cells track toward the northeast.
No changes have been made to the Slight and Marginal risk areas
across northwest MT/northern ID.
..Leitman.. 06/17/2022
.PREV DISCUSSION... /ISSUED 1124 AM CDT Fri Jun 17 2022/
...KY/TN to the Lower Mid-Atlantic and Southeast...
Remnants of a long-lived MCS continue to move generally
east-southeast across portions of KY/TN, with forward propagation
driven by renewed updrafts along the large-scale convective outflow.
It is plausible that this process will continue all the way to the
Atlantic Coast through sunset. More organized cold pool potential
will exist from eastern KY to southern VA/northern NC. Here,
stronger 700-500 mb westerlies along the southern periphery of a
robust mid-level jet over the Northeast will be coupled with the
trailing portion of a surface cold front. Otherwise, hot
temperatures will support a well-mixed boundary layer with scattered
damaging wind swaths from strong to locally severe wind gusts across
the Carolinas to GA.
...Northern High Plains...
West of the midlevel ridge over the Plains and east of a deep trough
near the West Coast, lee trough development is expected across the
High Plains. This trough should focus isolated, high-based
thunderstorm development during the late afternoon to early evening
immediately east of the higher terrain from eastern WY northward
into eastern MT. A very warm elevated mixed layer will tend to cap
the more moist boundary layer east of the lee trough and along a
warm front into eastern MT. This, combined with largely meridional
flow aloft, will keep convection close to the trough and higher
terrain. Given the very steep low to mid-level lapse rates, a
spatiotemporally confined corridor of scattered severe wind gusts
with isolated significant severe wind gusts may occur.
...Northwest MT...
Along and to the cool side of a quasi-stationary front draped across
the northern Rockies, multiple rounds of discrete supercell
development are possible during the period. The first will be
diurnally focused during the late afternoon to early evening, with
perhaps another round overnight as mid-level DCVA increases with
approach of the West Coast trough. Strong mid to upper-level speed
shear coupled with very steep mid-level lapse rates will support a
primary threat of large hail.
...New England...
Broken convection is ongoing across ME into western MA, along the
eastern edge of surface-based instability. Pockets of greater
surface heating are apparent ahead of this activity, mainly from MA
to far southwest ME. Mid-level lapse rates will remain poor and
forcing for ascent will be modest, which suggests that updrafts will
not be particularly robust. However, long, mostly straight
hodographs, with effective bulk shear in excess of 40 kt could
support a few storms with strong/damaging gusts and marginally
severe hail.
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/SSNw78
