- Денес
- Утре
- Day Three
000
acus01 kwns 221633
swody1
Storm Prediction Center ac 221632
Day 1 convective outlook
National Weather Service Storm Prediction Center Norman OK
1132 am CDT Fri Jun 22 2018
Valid 221630z - 231200z
..there is an enhanced risk of severe thunderstorms this afternoon
through late evening from eastern Colorado to northwestern OK...
..there is a slight risk of severe thunderstorms from parts of the
High Plains to the lower MS/Tennessee valleys and Virginia...
...
Scattered severe storms are expected across parts of the
central/Southern Plains, southeast and mid-Atlantic states today.
..eastern Colorado this afternoon to OK overnight...
Remnants of overnight convection persist from southern to
northwestern OK, though this convection should weaken slowly through
early afternoon. In the wake of these storms, the low levels will
modify through surface heating and boundary-layer dewpoints in the
50s will continue to spread northwestward into eastern Colorado.
Meanwhile, a midlevel trough is now moving across Utah/WY/northwestern
co, with ascent downstream from the trough supporting weak
convection over northern Colorado. Destabilization of the low levels will
remove convective inhibition, and early arrival of the ascent should
support storm development by early afternoon across eastern Colorado.
Moderate-strong buoyancy (mlcape of 2000-3000 j/kg), steep midlevel
lapse rates, and effective bulk shear near 50 kt are all supportive
of initial supercells with very large hail.
The storms should grow upscale through cell/outflow interactions,
with one or more clusters expected to move southeastward through
tonight. Damaging winds and hail will be the main threats with
storms focused along the instability gradient along the modifying
outflow and residual synoptic front from southwest Kansas and the
panhandles into western OK.
..lower MS to Tennessee Valley region today...
A series of speed maxima are rotating around the southern periphery
of a midlevel low over southern IL, one of which is associated with
the ongoing convection from southeastern Arkansas into northern MS. The
northern portion of this convection should spread eastward toward
northern Alabama through the afternoon in conjunction with the speed Max
and surface heating/destabilization, as well as moisture advection
from the southwest. A mix of multicell clusters and supercells will
be possible given effective bulk shear near 40 kt and MLCAPE
increasing to near 2000 j/kg, with an attendant threat for damaging
gusts and large hail.
Farther west, storms are ongoing from southeastern Arkansas into
northeastern la. Surface heating to the immediate south and
southwest, and boundary-layer dewpoints in the low-mid 70s, will
drive MLCAPE of 2000-3000 j/kg along the composite front/outflow
boundary and help maintain the storms through the day. This area
will remain along the southern fringe of the stronger mid-upper flow
from the west-northwest, though another possible mid-upper speed Max
will approach late this afternoon (now associated with the
convection along the Red River valley of TX/ok). A mix of multicell
clusters and supercells will be possible, and will likely
train/back-build through the day across southern Arkansas/northern la and
west central MS. Damaging winds and large hail will be the main
threats.
..VA area this afternoon/evening...
A lobe of ascent, as evidenced by the band of weak convection
ongoing from central WV to southwestern VA, will spread
east-northeastward today in association with an embedded speed Max
rotating around the southeastern periphery of the midlevel low over
southern Illinois. Though midlevel lapse rates are rather poor, surface
heating from NC into central Virginia will contribute to gradual
destabilization through the afternoon, and will likely support
scattered thunderstorm development. As the storms move
northeastward, they will encounter a slow-moving front from central
Virginia to the lower Chesapeake area. Low-level shear will be maximized
along this front, with sufficient hodograph curvature/srh to support
a threat for rotating storms with a tornado or two and isolated
damaging gusts later this afternoon through late evening.
.Thompson/Bentley.. 06/22/2018
$$
Mesoscale Discussion
000
acus11 kwns 221857
sels mesoscale discussion
Storm Prediction Center mesoscale discussion 221856
nez000-sdz000-ndz000-mtz000-wyz000-222030-
Mesoscale discussion 0823
National Weather Service Storm Prediction Center Norman OK
0156 PM CDT Fri Jun 22 2018
Areas affected...portions of the central/northern High Plains
Concerning...severe potential...watch unlikely
Valid 221856z - 222030z
Probability of watch issuance...20 percent
Summary...thunderstorms will increase in coverage through the
afternoon, and some will pose a damaging wind and large hail threat.
While a watch is not currently expected, convective trends will be
monitored for an increase in organization, which could necessitate a
watch.
Discussion...a severe thunderstorm has developed over the Black
Hills this afternoon, and other cells are developing within
confluence along a surface trough over the western Dakotas and
Nebraska Panhandle. As mid-level ascent continues to Foster new
development within this steep lapse rate environment, storms should
grow into multicell clusters, with some brief supercell structures
possible. However, relatively disorganized mid/upper wind profiles
should Foster more cluster modes that are driven east by merging
cold pools. Some threat for damaging winds and large hail will
continue to evolve, but a lack of greater organization casts doubt
on the need for a watch.
.Picca/Thompson.. 06/22/2018
..please see www.Spc.NOAA.Gov for graphic product...
Attention...WFO...bis...lbf...unr...cys...byz...ggw...
Latitude...Lon 41200388 41580401 43550436 45030447 45860458 46340452
46640428 46720410 46860366 46560318 45280282 43490233
41570180 41030197 41020304 41200388
