No watches are valid as of Fri Jul 26 23:08:02 UTC 2024.MD 1714 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHWESTERN MINNESOTA AND ADJACENT PORTIONS OF NORTH DAKOTA
Mesoscale Discussion 1714
NWS Storm Prediction Center Norman OK
0606 PM CDT Fri Jul 26 2024
Areas affected...northwestern Minnesota and adjacent portions of
North Dakota
Concerning...Severe potential...Watch unlikely
Valid 262306Z - 270100Z
Probability of Watch Issuance...20 percent
SUMMARY...One or two supercells may evolve through the 7-9 PM CDT
time frame, accompanied by potential for large hail and some risk
for a brief tornado. This is not anticipated to require a severe
weather watch, but trends are being monitored.
DISCUSSION...Beneath a plume of very warm elevated mixed-layer air,
a seasonably moist boundary-layer across parts of the Red River
Valley has become characterized by CAPE on the order of 2000-3000
J/kg. This is generally focused within narrow corridors near the
Red River, and immediately ahead of a weak eastward advancing cold
front. Although lingering mid-level inhibition has slowed
convective development, the initiation of sustained isolated to
widely scattered thunderstorm development appears underway.
Subtle mid-level cooling near the southern periphery of a mid-level
cyclone crossing the Canadian Prairies may gradually erode
inhibition further into early evening. However, based on the
various model output, it remains unclear whether this will become
supportive of a substantive increase in convective coverage. Even
so, given at least a narrow window for continuing inflow of
moderately unstable air, ongoing activity probably will continue to
intensify. One or two supercells may eventually evolve in the
presence of 35-50 kt southwesterly mid-level flow. Low-level
hodographs appear modest, but a brief tornado may not be out of the
question, in addition to a risk for large hail.
..Kerr/Hart.. 07/26/2024
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FGF...
LAT...LON 48439677 49859579 50169531 49399466 47809588 47819669
48439677
MD 1713 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL AND SOUTHERN ARIZONA
Mesoscale Discussion 1713
NWS Storm Prediction Center Norman OK
0521 PM CDT Fri Jul 26 2024
Areas affected...Central and Southern Arizona
Concerning...Severe potential...Watch unlikely
Valid 262221Z - 262345Z
Probability of Watch Issuance...20 percent
SUMMARY...Some severe gusts are possible as storms move off of the
higher terrain into an environment characterized by hot and dry
boundary-layer profiles. Due to the isolated nature of this
convection, watch issuance appears unlikely at this time.
DISCUSSION...Storms that developed this afternoon on the Mogollon
Rim have begun to move into southern Arizona and the lower terrain,
where hot and dry boundary layer profiles will support gusty
thunderstorm outflow capable of 60 MPH winds.
The greatest chances for severe wind gusts will be with the most
intense convective cores moving towards the eastern portions of
Phoenix, where some loose organization of outflow into a bowing
segment has been observed.
Further southeast near Tuscon, surface observations show cooler and
drier air, resulting in a relative minima of ML/MUCAPE. Any storms
that move into this environment may decrease in intensity more
quickly than western portions of the risk area.
..Halbert/Weinman/Hart.. 07/26/2024
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TWC...FGZ...PSR...
LAT...LON 34061133 33931110 33861099 33861084 33841070 33801051
33771024 33571020 33351016 33081028 32731050 32221087
32031113 31951157 32021189 32161213 32501225 32891226
33181217 33701200 34001172 34161153 34061133
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0247 PM CDT Fri Jul 26 2024
Valid 262000Z - 271200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS...GREAT BASIN...AND SOUTHWEST...
...SUMMARY...
Isolated severe thunderstorms may occur today across parts of the
northern Plains, Great Basin, and Southwest.
...20z Update...
Visible satellite shows cumulus development across the Black Hills
in South Dakota, with warming temperatures ahead of an approaching
cold front. Across much of central and eastern North and South
Dakota, skies are mostly sunny with a few high clouds and strong
mid-level capping in place. Thunderstorm development is expected by
late afternoon/evening as a mid-level wave moves eastward, aiding in
reducing inhibition. Storms will be capable of damaging winds and
large hail, though uncertainty remains in how many robust
thunderstorms will develop. The Marginal Risk area covers this
threat well.
Thunderstorm development is also expected this afternoon/evening
across the Great Basin into the Southwest, where well a mixed
boundary layer and steep mid-level lapse rates will support a
Marginal risk of strong to severe wind gusts through the afternoon
and evening.
Overall, trends are as expected with no changes needed to the D1
Convective Outlook.
..Thornton/Gleason.. 07/26/2024
.PREV DISCUSSION... /ISSUED 1126 AM CDT Fri Jul 26 2024/
...Northern Plains/Upper Midwest...
An upper trough/low will continue to move eastward across the
northern parts of the Canadian Prairie provinces today. An
associated surface cold front will extend northeast to southwest
from eastern ND into SD by late this afternoon. A substantial EML
and related cap should inhibit convective development along this
boundary for much of the day, even with substantial daytime heating
and the presence of moderate to strong instability. Still, most
guidance suggests that at least isolated thunderstorms may
eventually form by late this afternoon into evening as glancing
large-scale ascent associated with the upper trough/low overspreads
the northern Plains. 30-40 kt of deep-layer shear along and just
behind the front should support supercell structures with associated
hail/wind threat in any sustained convection. This isolated threat
should peak generally in the 22-05Z time frame. But, there is still
considerable uncertainty in how many robust thunderstorms will
develop along/behind the length of the front and subsequently spread
east-northeastward. Have therefore maintained a broad Marginal Risk
with this update.
...Great Basin...
In the wake of a mid-level shortwave trough, thunderstorm coverage
and intensity is generally expected to be less compared to
yesterday. Still, moderate instability should develop with daytime
heating across parts of eastern NV into western/northwest UT.
Scattered thunderstorms should once again form this afternoon across
these areas. A well-mixed boundary layer and steepened low-level
lapse rates should allow some of this activity to produce
occasionally strong to severe wind gusts. A secondary round, and
perhaps somewhat greater coverage of convection, may occur tonight
across parts of Nevada into western/northern Utah, influenced by the
eastward translation of a mid-level shortwave trough over northern
California.
...Southwest...
The mid-level anti-cyclone over northwest Mexico into the Southwest
is forecast to continue slowly weakening through the period as upper
ridging becomes more established over the Plains and Upper Midwest.
Modest mid-level northerly flow will be maintained over parts of the
Southwest, which may aid in convection moving off the higher terrain
of the Mogollon Rim, and mountains in southeast AZ. Morning visible
satellite imagery and surface observations show generally clear
conditions across these areas, which will foster robust daytime
heating. Even so, confidence in robust thunderstorms capable of
producing isolated strong/severe gusts reaching the lower desert
elevations is less compared to prior days, as mid-level flow should
remain rather weak.
...Coastal Carolinas...
Modest mid-level west-southwesterly flow will be present across the
Carolinas today, on the southern fringe of an upper trough over the
eastern states. Daytime heating of a moist airmass will support
moderate instability this afternoon. Deep-layer shear approaching
20-25 kt may foster occasionally organized updrafts, although poor
lapse rates should generally hinder more robust cores from
developing. While occasional strong/gusty winds may occur with any
thunderstorms that can develop and approach the coast through early
evening, the overall severe threat appears too isolated/marginal to
include low wind probabilities.
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0235 PM CDT Fri Jul 26 2024
Valid 271200Z - 281200Z
The main change to the Day 2 Fire Weather Outlook Update was to
expand isolated dry thunderstorm highlights westward to include
portions of western Idaho into eastern Oregon. The lack of
upper-level support and shallow buoyancy suggests that thunderstorm
development in these areas should be more sparse compared to places
farther east. Still, fuel beds in these areas remain receptive to
fire spread wherever dry strikes may occur, necessitating the
expanse of isolated dry thunderstorm highlights this outlook.
Otherwise, the previous forecast (see below) remains on track.
..Squitieri.. 07/26/2024
.PREV DISCUSSION... /ISSUED 0158 AM CDT Fri Jul 26 2024/
...Synopsis...
As a mid-level trough progresses eastward from California into the
northern Great Basin on Saturday, isolated dry thunderstorms are
expected across portions of eastern Idaho, southwestern Montana,
western Wyoming, and portions of far northern Utah. This trough is
also expected to bring dry and windy conditions to much of southern
Nevada into southwestern Utah.
...Dry Thunder...
An approaching trough from California is expected to bring chances
for isolated dry thunderstorms to portions of Idaho, Montana,
Wyoming, and Utah. Recent wetting rainfall could potentially limit
some lightning ignitions, but pockets of receptive fuels still
remain across much of the highlight area. Dry boundary-layer
profiles will support gusty thunderstorm outflow that could
contribute to wildfire spread with any lightning based ignitions.
...Southern Great Basin...
Relative humidity of 5-10% and wind speeds of 25-30 MPH are expected
across southern Nevada into southwestern Utah, exceeding the
meteorological criteria for critical conditions. However, there is
uncertainty in the receptiveness of fuels to wildfire spread due to
recent significant wetting rainfall, precluding the inclusion of
critical highlights at this time.
...Please see www.spc.noaa.gov/fire for graphic product...
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