SPC MD 961

MD 0961 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR WEST-CENTRAL TO SOUTHWEST OKLAHOMA AND NORTHWEST TEXAS
MD 0961 Image


Mesoscale Discussion 0961
NWS Storm Prediction Center Norman OK
0631 PM CDT Sun Jun 13 2021

Areas affected...West-central to southwest Oklahoma and northwest
Texas

Concerning...Severe potential...Watch unlikely 

Valid 132331Z - 140130Z

Probability of Watch Issuance...20 percent

SUMMARY...Scattered thunderstorms should continue to develop along
outflow boundaries through the late evening hours. This activity may
show periods of intensification that will pose a hail/damaging wind
threat. Due to low confidence in the coverage and duration of the
risk, a watch is not expected.

DISCUSSION...Thunderstorms continue to develop in the vicinity of a
remnant MCV that has lingered across southwest OK, as well as along
residual outflow boundaries and a weak confluence axis draped from
south-central to northwest OK. Although deep-layer flow is generally
weak over the region, dewpoints in the upper 60s and low 70s are
supporting 2000-3000 J/kg MLCAPE outside of existing cold pools.
Little to no inhibition will continue to allow new convective
development, and recent activity has shown pulse-like behavior with
periods of strong cloud-top cooling per GOES IR imagery. This
suggests that any cell could pose at least a brief damaging
wind/hail risk. The onset of diurnal cooling after 01 UTC may limit
the propensity for new convection, but recent hi-res guidance
suggests new storms may continue to develop along a southward-moving
outflow boundary and in the vicinity of the MCV as it continues to
move into northwest TX during the overnight hours. Confidence in
this scenario is low given how poorly guidance has handled the
evolution of the MCV thus far, but the potential for at least an
isolated severe threat is noted.

..Moore/Dial.. 06/13/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FWD...OUN...SJT...LUB...

LAT...LON   34449951 34799903 35259869 35719875 36229866 36379829
            36029780 35399754 34909731 34419693 34079692 33439715
            32919743 32729784 32599873 32799967 33299999 33940001
            34449951 

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SPC MD 960

MD 0960 CONCERNING SEVERE THUNDERSTORM WATCH 266... FOR PENNSYLVANIA
        
MD 0960 Image

Mesoscale Discussion 0960
NWS Storm Prediction Center Norman OK
0621 PM CDT Sun Jun 13 2021

Areas affected...Pennsylvania

Concerning...Severe Thunderstorm Watch 266...

Valid 132321Z - 140045Z

The severe weather threat for Severe Thunderstorm Watch 266
continues.

SUMMARY...Severe threat continues across mainly the western and
central portions of ww266.

DISCUSSION...Scattered robust convection has struggled to spread
east of the higher terrain. This is likely partly due to much
steeper lapse-rate environment extending across western NY, south
into Clearfield County PA. Primary updraft feed is from this steeper
lapse-rate plume and given the slow forward propagation, new
updrafts may continue to develop in proximity to higher buoyancy.
For these reasons, western and central portions of ww266 may remain
most active.

..Darrow.. 06/13/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...PHI...BGM...BUF...CTP...PBZ...

LAT...LON   41907896 42157562 40547562 40327896 41907896 

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SPC MD 959

MD 0959 CONCERNING SEVERE THUNDERSTORM WATCH 267... FOR CENTRAL APPALACHIANS
        
MD 0959 Image

Mesoscale Discussion 0959
NWS Storm Prediction Center Norman OK
0605 PM CDT Sun Jun 13 2021

Areas affected...Central Appalachians

Concerning...Severe Thunderstorm Watch 267...

Valid 132305Z - 140030Z

The severe weather threat for Severe Thunderstorm Watch 267
continues.

SUMMARY...Thunderstorms will propagate from north to south across
ww267. Locally damaging winds remain possible.

DISCUSSION...Northwesterly high-level diffluent flow remains
favorable for southward-propagating convection this evening. Latest
diagnostic data suggests a weak mid-level short-wave trough may be
embedded within this flow and is likely contributing to an extensive
corridor of convection that stretches from central PA-KY. Over the
last few hours, a slow-moving MCS has evolved across central WV,
extending into western VA. This activity is moving south at roughly
20kt into a region of yet-to-be overturned air where low-level lapse
rates remain steep and instability sufficient for robust updrafts.
The primary concern is locally damaging winds as this convection
spreads toward the southern portions of ww267. At the current
speed/movement, leading edge of the MCS should exit the watch around
expiration.

..Darrow.. 06/13/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...RNK...RLX...JKL...

LAT...LON   37758279 38558077 38247980 37447925 37188024 37288161
            37758279 

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SPC MD 958

MD 0958 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN COLORADO AND NORTHEAST NEW MEXICO
MD 0958 Image


Mesoscale Discussion 0958
NWS Storm Prediction Center Norman OK
0559 PM CDT Sun Jun 13 2021

Areas affected...Eastern Colorado and northeast New Mexico

Concerning...Severe potential...Watch unlikely 

Valid 132259Z - 140100Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated to scattered thunderstorms will continue to
develop along the Front Range of the Rockies over the next few
hours. A few storms may be strong to severe and pose a hail and/or
damaging wind risk. This threat should remain somewhat limited, and
a watch is not expected.

DISCUSSION...Regional radar imagery shows convective initiation well
underway across central CO within an upslope flow regime. Dewpoints
in the mid to upper 50s along the central high Plains are supporting
MLCAPE values of 500-1000 J/kg across northeast NM, increasing to
1500 J/kg across central/northeast CO. 40-50 knot flow (sampled by
KPUX and KFTG VWPs) between 5-7 km on the eastern periphery of an
upper-level ridge is supporting effective bulk shear values between
30-40 knots - sufficient for organized convection. Steep mid-level
lapse rates as well as 9 C/km 0-3 km lapse rates will support a hail
and damaging wind risk with any mature convection. Despite the
favorable environment, coverage of severe storms is expected to
generally be limited in nature due to weak forcing for ascent and
lingering MLCIN over the region. As such, a watch is not expected.

..Moore/Dial.. 06/13/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...GLD...AMA...PUB...BOU...ABQ...

LAT...LON   36000502 37060506 38740507 39720512 40340510 40530440
            40380372 39940322 39200285 38720277 37440279 36090287
            35230347 34910385 34800435 34990491 35360496 36000502 

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SPC MD 957

MD 0957 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHERN OREGON INTO EASTERN WASHINGTON
MD 0957 Image


Mesoscale Discussion 0957
NWS Storm Prediction Center Norman OK
0520 PM CDT Sun Jun 13 2021

Areas affected...Northern Oregon into eastern Washington

Concerning...Severe potential...Watch unlikely 

Valid 132220Z - 140015Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated thunderstorms are expected to develop through the
late afternoon and into the early evening, and will likely pose a
hail/wind threat. This risk is expected to remain too isolated for a
watch issuance.

DISCUSSION...GOES visible imagery shows a growing field of deepening
cumulus across central to north-central OR. This is likely
associated with modest warm air advection near 700 mb ahead of an
approaching upper-level shortwave trough (which is currently moving
up the West Coast per water-vapor imagery). A few stronger, but
transient reflectivity cores have been noted within this field in
regional radar imagery, and the potential for sustained convection
will increase over the next 1-2 hours as stronger forcing for ascent
arrives. Strong deep-layer flow over the region is supporting 50-60
knots of 0-6 km bulk shear, which will help organize any persistent
convection. One limiting factor is the limited instability with only
250-500 J/kg MUCAPE noted in mesoanalysis estimates. Continued
daytime heating should yield sufficient instability for a few
isolated storms by late afternoon into the early evening, which may
pose a hail/wind risk, but the overall threat should be too limited
to warrant a watch.

Further east across the ID/MT border, greater instability is noted
and a few scattered convective showers have developed along the
Sawtooth Mountains. However, this region is displaced from more
favorable deep-layer shear and stronger forcing for ascent, yielding
low confidence in the overall severe potential.

..Moore/Dial.. 06/13/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...OTX...PDT...MFR...PQR...

LAT...LON   43992233 45292168 47402069 48031996 48001857 47811737
            47491710 46581786 45601861 44571928 43962000 43602098
            43112154 42492208 42472269 43252262 43992233 

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