SPC Mesoscale Discussions

MD 0608 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR CENTRAL/SOUTH-CENTRAL OK

Mesoscale Discussion 0608
NWS Storm Prediction Center Norman OK
0608 PM CDT Thu May 02 2024

Areas affected...Central/South-Central OK

Concerning...Severe potential...Watch unlikely 

Valid 022308Z - 030115Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated large hail up to 1" in diameter is possible
across portion of central and south-central Oklahoma this evening.

DISCUSSION...Recent radar and visible satellite imagery has shown
some modest increase in both thunderstorm coverage and intensity
over central OK during the past half hour or so, some of which
occurred along the cold front and some of which developed to the
southeast of a weak frontal low. The air mass is uncapped and
moderately buoyant, so some additional thunderstorm development is
anticipated across the region as the cold front slowly pushes
southward/southeastward. A predominately multicellular mode is
anticipated but moderate vertical shear (i.e. around 35-40 kt of
effective bulk shear) is in place across the region, which should be
sufficient for a few more organized storm structures. Consequently,
some isolated hail up to 1" in diameter appears possible this
evening with any of the more mature/organized storms. Overall severe
coverage is expected to remain isolated, likely precluding the need
for a watch. However, convective trends across the region are being
monitored closely.

..Mosier/Guyer.. 05/02/2024

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

ATTN...WFO...TSA...OUN...

LAT...LON   35189897 36029774 35949629 34659634 34069708 34179834
            34519901 35189897 

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MD 0607 CONCERNING SEVERE THUNDERSTORM WATCH 177… FOR NORTHWEST TX INTO SOUTHWEST TX INTO THE TX HILL COUNTRY

Mesoscale Discussion 0607
NWS Storm Prediction Center Norman OK
0535 PM CDT Thu May 02 2024

Areas affected...Northwest TX into Southwest TX into the TX Hill
Country

Concerning...Severe Thunderstorm Watch 177...

Valid 022235Z - 030000Z

The severe weather threat for Severe Thunderstorm Watch 177
continues.

SUMMARY...Supercells capable of very large hail up to 2-3" in
diameter and gusts up to 75 mph remain possible. Additional
development is possible over the Texas Hill Country and trends will
be monitored for additional watch issuance.

DISCUSSION...Regional radar imagery depicts two mature supercells,
one in King County and the other farther south in Runnels County.
Visible satellite imagery reveals several attempts at additional
development between these two mature storms. Environmental
conditions support supercells and the general expectation is for the
newer development to mature. Primary severe risk with these storms
is very large hail around 2" to 3" in diameter. A few damaging gusts
up to 75 mph are possible as well. 

Farther south (from southwest TX into the TX Hill Country), cumulus
has been gradually deepening, although convective
initiation/lightning has not been realized. The mesoscale
environment in this area will be influenced by a westward-moving
outflow boundary, which could provide the additional lift needed for
convective initiation. Large to very hail is possible with new
updrafts. However, cooler temperatures behind the outflow could act
as a deterrent for sustained development, and the overall
longevity/severity of this newer development is uncertain. Some
initiation is possible south of Severe Thunderstorm Watch 177, and
convective trends will be monitored closely in this area for
additional watch issuance.

..Mosier/Guyer.. 05/02/2024

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

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

LAT...LON   30330071 31780037 33900003 33529859 29369895 28799982
            29350051 30330071 

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MD 0606 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF NORTHEAST ILLINOIS AND NORTHERN INDIANA

Mesoscale Discussion 0606
NWS Storm Prediction Center Norman OK
0307 PM CDT Thu May 02 2024

Areas affected...Portions of northeast Illinois and northern Indiana

Concerning...Severe potential...Watch unlikely 

Valid 022007Z - 022200Z

Probability of Watch Issuance...20 percent

SUMMARY...Widely scattered thunderstorms are expected to continue
through this afternoon across portions of northern Illinois and
Indiana. A few thunderstorms could produce hail of 1-1.25 inches in
diameter and wind gusts near 60 mph.

DISCUSSION...Recent radar trends show an area of deep moist
convection developing along a warm front lifting northward across
northern Indiana and Illinois. Meanwhile, aloft, a mid to upper
level shortwave trough apparent in water vapor imagery now crossing
the Dakotas and an associated mid level jet max were progressing
east northeastward. Buoyancy behind the warm front will continue to
increase through late this afternoon, along with a slow increase in
mid to upper flow/deep effective shear via the shortwave trough to
the northwest. However, most of the large scale ascent associated
with the latter will remain well northwest of the unstable air mass
and severe convective coverage is expected to remain rather limited.
Some updraft intensification could occur within a few cells that
manage to avoid interactions through peak daytime heating. Any of
these more robust thunderstorms that manage to develop could briefly
become severe.

..Barnes/Lyons/Hart.. 05/02/2024

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

ATTN...WFO...IWX...IND...LOT...ILX...MKX...DVN...

LAT...LON   40418993 42418899 42698886 42778860 42798826 42788814
            42718785 42638772 42438760 42308755 42188748 42028716
            41798673 41588638 41488607 41198554 40928528 40818479
            40388484 40398590 40608695 40638820 40418993 

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MD 0605 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR PARTS OF NORTHWEST TEXAS

Mesoscale Discussion 0605
NWS Storm Prediction Center Norman OK
0207 PM CDT Thu May 02 2024

Areas affected...parts of northwest Texas

Concerning...Severe potential...Watch likely 

Valid 021907Z - 022130Z

Probability of Watch Issuance...80 percent

SUMMARY...Intensifying thunderstorm development, including a couple
of evolving supercells with potential to producing large hail in
excess of 2 inches in diameter and perhaps a tornado or two, appears
increasingly likely by 4-6 PM CDT.

DISCUSSION...A zone of differential surface heating continues to
become better defined across parts of the Texas South Plains into
central Texas, with stronger boundary-layer heating and mixing
ongoing to the west of air impacted by overnight convection.  A weak
surface low appears to be developing along this boundary between
Childress and Abilene, with a developing area of strengthening warm
advection to its east and southeast.  This appears to be
contributing to ongoing gradually deepening convective development,
beneath a plume of warm and capping elevate mixed-layer air.

Along and east of a sharpening dryline, to the south of the low, a
seasonably moist boundary-layer is becoming characterized by
mixed-layer CAPE up to 3000 J/kg.  Low-level wind fields are light,
but veering with height beneath 25-50 kt flow in the 500-300 mb
layer appears to be contributing to sufficient shear for supercells.

Although potential mid/upper forcing for thunderstorm development
remains unclear, latest model output suggests that lift associated
with warm advection, coupled with the approach of convective
temperatures, will contribute to increasing probabilities for
thunderstorm initiation through 21-23Z.  Once this occurs,
intensification may be rapid, with stronger storms becoming capable
of producing large hail and perhaps posing a risk for tornadoes.

..Kerr/Hart.. 05/02/2024

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

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

LAT...LON   31870052 33060048 34210085 34079944 33479900 32899890
            31879943 31870052 

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MD 0604 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR NORTHERN AND CENTRAL OK…SOUTHEAST KS…AND CENTRAL MO

Mesoscale Discussion 0604
NWS Storm Prediction Center Norman OK
0142 PM CDT Thu May 02 2024

Areas affected...Northern and central OK...southeast KS...and
central MO

Concerning...Severe potential...Watch unlikely 

Valid 021842Z - 022045Z

Probability of Watch Issuance...20 percent

SUMMARY...Scattered thunderstorm development will continue through
this afternoon across northern OK, far southeastern KS, and central
MO. Marginally severe hail up to the size of half dollars (1-1.5
inches) and localized wind gusts up to 60 mph will be possible with
any robust updrafts.

DISCUSSION...Latest visible satellite imagery and surface
observations show a cold front progressing southward into northern
OK extending from Lawrence, KS southwestward just through Alva, OK.
An MCV over far northeastern OK will continue to slowly advance ENE
this afternoon. Linear forcing along the cold front has resulted in
enough ascent for a cluster of deep moist convection to develop
across SE KS. Further northeast across far eastern KS and central
MO, a few more multicell clusters have developed along a weakly
forced stationary boundary. As the cold front continues to nudge
southward into north central OK, additional linear multicell
clusters will likely develop along it, while more widely scattered
development persists ahead of the MCV over MO.

The environment across the region is not particularly favorable for
supercells given inadequate deep layer shear and low buoyancy
(widespread cloud cover has persisted through most the day). 
However, as insulation continues to increase this afternoon and a
slow increase in mid to upper flow spreads eastward, some organized
updrafts are possible. Convective trends will be monitored for
intensification.

..Barnes/Lyons/Hart.. 05/02/2024

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

ATTN...WFO...LSX...DVN...SGF...EAX...TSA...TOP...ICT...OUN...

LAT...LON   34979734 35539833 36599809 37979605 38279578 39999449
            40589226 40449154 39759141 39249078 38669101 37889165
            36289453 34979734 

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