No watches are valid as of Wed Jun 26 18:08:03 UTC 2019.MD 1254 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF SOUTHERN/EASTERN MO...SOUTHERN/CENTRAL IL...FAR WESTERN KY/TN...AND FAR NORTHERN AR
Mesoscale Discussion 1254
NWS Storm Prediction Center Norman OK
0106 PM CDT Wed Jun 26 2019
Areas affected...Portions of southern/eastern MO...southern/central
IL...far western KY/TN...and far northern AR
Concerning...Severe potential...Watch possible
Valid 261806Z - 262000Z
Probability of Watch Issuance...40 percent
SUMMARY...Loosely organized storms may produce isolated damaging
winds and hail this afternoon. Watch issuance is possible.
DISCUSSION...A MCV from earlier convection centered over
southwestern MO will move eastward across southern MO this
afternoon. Surface temperatures have warmed generally into the
mid/upper 80s, with dewpoints in the lower to mid 70s downstream of
this MCV across the mid MS Valley and vicinity. A resultant strongly
unstable airmass exists, with MLCAPE around 2500-3500 J/kg per
latest mesoanalysis. At least scattered thunderstorms are expected
to blossom over the next couple of hours across southern/eastern MO
along outflow emanating from the MCV and subsequently spread
eastward through the afternoon and early evening. Around 25-40 kt of
westerly flow exists in the 2-6 km AGL layer in association with the
MCV based on recent VWP from KSGF. This modestly enhanced low to
mid-level flow may prove sufficient to loosely organize these
thunderstorms into one or more clusters. Given the strong
instability and steep low-level lapse rates owing to ample diurnal
heating, isolated damaging winds could occur with this convection,
along with some hail in the more robust updrafts. It remains unclear
whether the modest shear provided by the MCV will prove sufficient
for a more organized hail/wind threat. Regardless, Severe
Thunderstorm Watch issuance is possible this afternoon for some part
of this region.
..Gleason/Hart.. 06/26/2019
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PAH...ILX...MEG...LSX...LZK...SGF...
LAT...LON 36189195 36349280 36679311 37169191 37699169 38439158
39119138 39729118 40029024 40038915 39268835 38338808
37568812 36978837 36338885 36148983 36149080 36189195
MD 1253 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL NEW YORK AND NORTHERN PENNSYLVANIA.
Mesoscale Discussion 1253
NWS Storm Prediction Center Norman OK
1256 PM CDT Wed Jun 26 2019
Areas affected...Central New York and northern Pennsylvania.
Concerning...Severe potential...Watch unlikely
Valid 261756Z - 261930Z
Probability of Watch Issuance...20 percent
SUMMARY...Strong to occasionally severe storms expected this
afternoon and into the evening. No watch is expected.
DISCUSSION...Boundary layer heating/moistening has begun to
destabilize portions of the upper Ohio Valley into the Northeast.
Convective temperatures on 12Z BUF and PIT RAOB were in the low 80s
suggesting convective initiation is likely imminent. This is further
supported by the expanding cumulus field and weak radar echos across
northern Pennsylvania and western New York. MLCAPE is only around
500-1000 J/kg at this time, but is expected to increase to around
1500 J/kg by later this afternoon as the surface continues to warm
and low-level moisture continues to advect northeastward. Mostly
unidirectional flow will be a limiting factor to storm organization,
but mid-level flow around 40 knots per BUF 12Z sounding should
provide ample speed shear for multicell storm structures. In
addition, flow increases to 30 to 35 knots around 1 to 1.5 km which
may provide sufficient flow for stronger winds to mix toward the
surface. Weak mid-level lapse rates (6-6.5 C/km) should limit
updraft intensity and a greater severe threat, but the combination
of instability and shear should be sufficient for a few strong to
severe multicell storm clusters and a threat for isolated damaging
winds and large hail.
..Bentley/Hart.. 06/26/2019
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BTV...ALY...BGM...BUF...CTP...PBZ...CLE...
LAT...LON 42267920 42617839 43277722 44627603 45007528 45107465
45097395 44397377 43527389 42357439 41717488 41337555
41077655 40967767 40937875 41077992 41708045 42267920
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1124 AM CDT Wed Jun 26 2019
Valid 261630Z - 271200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS GENERALLY FROM
EASTERN OREGON ACROSS THE NORTHERN ROCKIES/PLAINS TO PARTS OF
ILLINOIS AND SOUTHEASTERN MISSOURI...
...SUMMARY...
Severe thunderstorm winds and hail are most probable today into
tonight from eastern Oregon across the northern Rockies/Plains to
parts of Illinois and southeastern Missouri.
...WA/OR/ID...
A band of strong southwesterly flow aloft extends from OR/CA
northeastward into ID/WY/MT. One core of strong winds will nose
into southern OR this afternoon, with enhanced lift spreading into
northeast OR/southeast WA. Strong heating, cool temperatures aloft,
and sufficient CAPE will aid in the development of scattered
thunderstorms in this region. Forecast soundings in this area show
pockets of MLCAPE of 500-1000 J/kg and inverted-v profiles. Also,
strong vertical shear will be present. This will result in an
environment favorable for a combination of multicell clusters and a
few high-based supercells capable of damaging winds and hail. The
storms will likely spread into central/northern ID this evening.
...MT into northeast WY...
Strong heating is also occurring over much of MT today, where
surface dewpoints range from the 40s in the western mountains into
the 50s over the southeast. Thunderstorms should develop by
mid-afternoon along an east-west axis near the WY/MT border and lift
northeastward through the evening. Hail and damaging winds will be
possible throughout this corridor, but appear more likely over
southeast MT into northeast WY where better low-level moisture will
increase coverage/longevity of storms.
...NE/SD/MN...
One or more clusters of thunderstorms are expected to develop over
western SD/NE this evening and propagate eastward across the Plains
tonight. Initial storms would likely be supercellular, with growth
upscale into a bowing structure farther east. There is uncertainty
how far east this activity may persist, but a few model solutions
suggest they could make it into MN late tonight before weakening.
...MO/IL...
A well-defined MCV is present this morning over southwest MO. All
12z guidance is consistent in developing scattered thunderstorms
this afternoon ahead of the feature. Vertical shear profiles are
weak, suggesting that activity will be relatively poorly organized
and chaotic. However, ample low level moisture, large CAPE values,
and mesoscale organization of the MCV provide sufficient support to
maintain the ongoing SLGT risk forecast.
..Hart/Bentley.. 06/26/2019
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1200 PM CDT Wed Jun 26 2019
Valid 271200Z - 281200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR
WEST-CENTRAL INTO NORTHEAST MONTANA...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN
MINNESOTA INTO NORTHERN ILLINOIS...
...SUMMARY...
Scattered thunderstorms capable of very large hail, intense wind
gusts and perhaps a couple of tornadoes will be possible across
portions of west-central into northeastern Montana Thursday
afternoon and night.
...Northern Rockies into ND...
A stationary mid-level low is forecast at the mouth of the Columbia
River through early Friday morning. A belt of strong cyclonic 500mb
flow (50+ kt) is forecast to overspread the western half of MT
during the day while weak mid-level ridging occurs downstream across
the Dakotas/MN vicinity. An elongated area of low pressure will
extend from the northern Great Basin northward through WY and MT.
Models show low-level easterly flow to the north of a primary area
of surface low pressure forecast near the WY/MT border during the
day. A low-level moisture plume will extend from the western
Dakotas and arc into central and southwest MT. Strong heating atop
a moistening and destabilizing boundary layer, steep 700-500mb lapse
rates (8 degrees C/km) and strengthening deep shear profiles will
conditionally support severe storm development by mid afternoon. A
capping inversion noted on forecast soundings will likely erode over
southwest and west-central MT by late afternoon with initial storm
development forecast over the higher terrain in southwest MT. As
widely scattered storms move east-northeast into the moist axis,
storm intensity will increase near and east of I-15. Several
supercells will probably develop by late afternoon into the early
evening across central MT in anomalously rich low-level moisture for
the northern High Plains. Large to very large hail and severe gusts
are possible. Some forecast soundings show long hodographs with
enlargement in the low levels. In addition to supporting storm
structures capable of large to very large hail, a few tornadoes are
also possible, perhaps focused in the southwest part of the
30-percent severe probability area from Lewistown to Great Falls,
and near Helena. The latest HREF guidance is seemingly in large
agreement for this scenario. Eventual upscale growth into one or
more clusters is forecast to move east-northeast during the evening
and overnight and be capable of a risk for severe gusts.
Other isolated strong to severe storms are forecast over northern
ID, south-central MT. Isolated hail/wind are the primary risks with
these storms.
...Mid-MO Valley to Great Lakes...
Severe potential further east/southeast is more mesoscale driven and
partially dependent on convection expected across the region in the
Day 1/Wednesday period, which could still be ongoing across parts of
the area at 12z Thursday. The net result is considerable
uncertainty and potentially complex scenario for convective
evolution. Nonetheless, a very moist and unstable airmass will
reside across the region with 35-45 kt midlevel northwesterly flow
spreading eastward in conjunction with a shortwave impulse topping
the larger-scale ridge. Outflow boundaries and potentially one or
more MCVs will ultimately determine where a greater severe threat
unfolds, with large hail and damaging winds the primary hazards. A
corridor from southern MN towards northern IL appears to be a
general zone for an area of greater severe coverage. Adjustment of
15-percent severe probabilities will likely be needed in later
outlooks.
...MAXIMUM RISK BY HAZARD...
Tornado: 5% - Slight
Wind: 30% SIG - Enhanced
Hail: 30% SIG - Enhanced
..Smith.. 06/26/2019
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