Thursday, June 27, 2019

SPC Jun 28, 2019 0100 UTC Day 1 Convective Outlook

SPC 0100Z Day 1 Outlook
Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0802 PM CDT Thu Jun 27 2019

Valid 280100Z - 281200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTHEASTERN MT...

...SUMMARY...
Thunderstorms capable scattered damaging wind gusts, isolated large
hail, and perhaps a tornado or two will be possible across portions
of central into northeastern Montana and western North Dakota this
evening and tonight. Other isolated strong to severe storms may
occur overnight across parts of the Upper Midwest.

...Northern High Plains...
Storms have grown upscale into a bowing complex across north-central
MT early this evening. Tendency should be for this convection to
continue east-northeastward this evening and overnight as low-level
easterly flow strengthens across eastern MT and western ND. With a
linear mode expected to remain dominant, damaging winds should be
the primary threat. But, isolated large hail and a tornado or two
remain possible in the short term with any supercells embedded
within the line given the strong shear that will be present across
this region. Depending on the track of these storms this evening, an
isolated damaging wind threat may continue into parts of western ND
late tonight.

...Upper Midwest and Great Lakes...
A long-lived MCS has recently weakened over Lake Michigan and
northeastern IL. The airmass downstream of this line of storms is
only weakly unstable. While a very isolated strong/gusty wind threat
could persist through the next hour or two into western Lower MI and
northern IN, increasing convective inhibition with eastward extent
this evening should greatly limit the overall severe threat.

In the wake of this activity, there is some potential for additional
robust thunderstorm development across parts of southern MN into
northern IA and WI this evening and overnight as a southwesterly
low-level jet strengthens across this area. A convectively
reinforced boundary lies northwest to southeast from southern MN
into northeastern IA this evening. If storms do redevelop on/near
this boundary, they will have the potential to become severe.
Effective bulk shear of 35-45 kt would conditionally support
supercells, and steep mid-level lapse rates observed on the 00Z OAX
sounding have likely overspread this region based on latest
mesoanalysis estimates. Isolated large hail would be an initial
threat with more discrete convection, with strong/gusty winds
possible if storms can congeal into a line and spread
south-southeastward along the surface boundary later tonight.
Primary uncertainty remains if storms will initiate across this
region on the warm or cool side of this boundary. The Marginal Risk
across the Upper Midwest has been reconfigured to account for this
convective potential tonight.

...Elsewhere...
Isolated strong to severe thunderstorm potential will continue to
diminish this evening across parts of the Mid Atlantic, Southeast,
and southern High Plains with the loss of daytime heating. Weak
shear across this regions should preclude an organized severe threat
from persisting overnight.

..Gleason.. 06/28/2019

Read more

from SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_0100.html

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