SPC MD 1304

SPC MD 1304

MD 1304 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR FAR NORTHEAST WY...WESTERN HALF OF SD
MD 1304 Image

Mesoscale Discussion 1304
NWS Storm Prediction Center Norman OK
0228 PM CDT Wed Jun 29 2022

Areas affected...far northeast WY...western half of SD

Concerning...Severe potential...Watch possible 

Valid 291928Z - 292200Z

Probability of Watch Issuance...60 percent

SUMMARY...Thunderstorms are forecast to develop and intensify
through the remainder of the afternoon into the early evening. 
Severe gusts ranging from 60-75 mph are possible with the stronger
downdrafts.

DISCUSSION...Visible satellite imagery shows developing high-based
convection over northeast WY with a mid-level accas field spreading
east into western SD near the Black Hills.  Clear skies east of
Rapid City have resulted in strong heating with surface temperatures
around 100 deg F and dewpoints around 50.  Forecast soundings
indicate a nearly dry adiabatic lapse rate from the surface to 500
mb based on current surface observations.  Model guidance,
particularly the HRRR, shows storms gradually developing as
convection moves east from near the WY/SD border (surface dewpoints
in the 30s to lower 40s) into slightly richer moisture farther east
near Phillips (dewpoints around 50 deg F).  A semi-organized cluster
of initially skeletal but increasingly robust storms will probably
evolve, with widely scattered to scattered severe gusts ranging from
60-75 mph as this activity moves into central SD towards early
evening.

..Smith/Hart.. 06/29/2022

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

ATTN...WFO...ABR...UNR...CYS...

LAT...LON   44810479 45560099 45160051 44440048 43790067 43430151
            43460456 44140498 44810479 

Read more
SPC MD 1303

SPC MD 1303

MD 1303 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHEAST UT...FAR NORTHWEST CO...FAR SOUTHWEST WY
MD 1303 Image

Mesoscale Discussion 1303
NWS Storm Prediction Center Norman OK
0141 PM CDT Wed Jun 29 2022

Areas affected...northeast UT...far northwest CO...far southwest WY

Concerning...Severe potential...Watch unlikely 

Valid 291841Z - 292115Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated severe gusts (60-70 mph) are possible with the
strongest storms/outflow.  The isolated coverage and low impact of
the risk will preclude a severe thunderstorm watch.

DISCUSSION...Visible satellite imagery over the eastern Great
Basin/central Rockies shows a cluster of weakening convection moving
east over northern CO/southern WY and approaching the Laramie Range.
In wake of this activity, strong heating with mostly sunny skies is
resulting in temperatures warming into the lower to mid 80s from
southwest WY into northeast UT and adjacent parts of far northwest
CO.  Isolated to widely scattered storms have developed in the past
hour over the Uinta mountains with additional storms forming farther
south over the Wasatch.  KMTX and KSLC VAD data indicate around
30-40kt west-southwesterly 500mb flow.  Given the steep lapse rate
profiles and the relatively dry sub-cloud layer implied by the large
surface temperature-dewpoint spreads, strong downdrafts may be
slightly augmented by the moderate background tropospheric flow. 
Isolated severe gusts (60-70 mph) are possible with the stronger
cores.

..Smith/Hart.. 06/29/2022

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

ATTN...WFO...RIW...GJT...SLC...

LAT...LON   41051082 41670890 41580812 41060793 40510808 40160857
            39411094 41051082 

Read more
SPC Jun 29, 2022 1730 UTC Day 2 Convective Outlook

SPC Jun 29, 2022 1730 UTC Day 2 Convective Outlook

SPC 1730Z Day 2 Outlook
Day 2 Outlook Image
Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1229 PM CDT Wed Jun 29 2022

Valid 301200Z - 011200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE UPPER MIDWEST TO THE CENTRAL PLAINS...

...SUMMARY...
Strong thunderstorms may impact a corridor from the central Great
Plains into the Upper Midwest and adjacent Great Lakes region
Thursday. Strong gusts will be the main hazard with this activity,
though isolated hail may also occur.

...MO Valley to the Great Lakes Vicinity...

A shortwave trough embedded within a broad, larger-scale trough over
central Canada into the Upper Midwest will shift northeast across
Lake Superior Thursday morning ahead of the main upper trough axis.
Strong mid/upper westerly flow will reside over the northern
Plains/Upper Midwest associated with this feature. At the surface, a
seasonally moist airmass will be in place, with dewpoints in the
low/mid 60s beneath steep midlevel lapse rates. A cold front will
extend from a low over western Ontario into the eastern Dakotas and
western NE. Showers and isolated thunderstorms will likely be
ongoing across parts of ND/MN/WI/MI Thursday morning. This activity,
and residual cloud cover will inhibit stronger heating to some
degree. Additionally, warm midlevel temperatures will further result
in weak inhibition. Nevertheless, by afternoon, sufficient
destabilization should occur, supporting isolated to widely
scattered thunderstorm development ahead of the east/southeast
advancing cold front. 

Effective shear magnitudes greater than 35-40 kt should foster
organized cells with an accompanying threat for damaging gusts.
Somewhat straight and elongated hodographs typical of supercells
capable of hail are evident in forecast soundings, though confidence
in large hail is limited given warmer midlevel temperatures. Any
supercells that develop may be somewhat short-lived given at least
weak inhibition persisting ahead of the front and tendency toward
outflow dominant convection along the front. Expected limited storm
coverage and intensity will preclude an upgrade to Slight risk at
this time.

...Central Plains Vicinity...

Several shortwave impulses are forecast to migrate across the
central Rockies into NE/KS Thursday afternoon/evening. Northeasterly
post-frontal upslope low-level flow will maintain modest
boundary-layer moisture. Additionally, easterly low-level flow
beneath mid/upper level westerlies will result in effective shear
magnitudes around 25-35 kt. Weak destabilization by afternoon will
result in convection first over the higher terrain of CO/WY. As this
activity spreads eastward, some organized high-based cells should
persist into the Plains. Inverted-v sub-cloud thermodynamic profiles
with very steep low-level lapse rates should foster some threat for
strong gusts across eastern CO into parts of NE/KS into the evening
hours.

..Leitman.. 06/29/2022

Read more
SPC Day 1 Fire Weather Outlook

SPC Day 1 Fire Weather Outlook

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook Image
Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
1146 AM CDT Wed Jun 29 2022

Valid 291700Z - 301200Z

...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE CENTRAL HIGH
PLAINS...

...Dry Thunder...
Morning observations showed cloudy skies ongoing within and ahead of
a second surge of monsoon moisture moving across the Southwest
toward the Four Corners. 12z area RAOBs show PWATs ranging from 0.75
to 1+ inches across much of the Southwest and Western Slope. With
several preceding days of scattered wetting rains, area fuels
(especially short-hour and high elevations) have been significantly
tempered. With another round of scatted storms expected this
afternoon and evening, dry thunder probabilities appear
significantly lower. While occasional drier strikes may develop
outside of the wetter cores within the drier heavy fuel loads, the
IsoDryT area has been focused across Northern UT and eastern NV away
from the heaviest precipitation accumulations. 

Elsewhere the previous outlook remains valid with only minor
adjustments to the Elevated and Critical Areas with the latest
guidance. See the prior discussion for more details.

..Lyons.. 06/29/2022

.PREV DISCUSSION... /ISSUED 0145 AM CDT Wed Jun 29 2022/

...Synopsis...
A mid-level trough will eject into the northern Plains today as an
upper ridge persists across the central and southern U.S. Surface
lee troughing across the Plains states will encourage Elevated to
Critical dry/windy conditions this afternoon across parts of western
into central Nebraska and immediate surrounding areas. Isolated to
scattered high-based thunderstorms may also develop, with abundant
rainfall evaporation potentially supporting strong to severe wind
gusts, which may exacerbate wildfire-spread potential. Isolated dry
thunderstorm highlights have been withheld this outlook since it is
unclear how much rainfall may accompany storms. Please see the Day 1
Convective Outlook for more details on the severe threat. 

Strong flow aloft may also linger across the northern and central
Great Basin, where a dry boundary layer may encourage downslope flow
and associated Elevated dry and windy conditions to the lee of the
Sierra. Monsoonal moisture meandering around the eastern Great Basin
will support isolated to scattered high-based thunderstorms by
afternoon peak heating. The potential exists for isolated dry
strikes in receptive fuel beds, warranting the continuation of
isolated dry thunderstorm highlights.

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

Read more