RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Sat Mar 25 14:40:02 UTC 2023.
MD 0339 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF CENTRAL INTO SOUTHERN GEORGIA
Mesoscale Discussion 0339
NWS Storm Prediction Center Norman OK
0938 AM CDT Sat Mar 25 2023
Areas affected...portions of central into southern Georgia
Concerning...Severe potential...Watch possible
Valid 251438Z - 251545Z
Probability of Watch Issuance...40 percent
SUMMARY...At least isolated severe thunderstorms appear plausible
late this morning going into the afternoon hours. Damaging gusts and
perhaps a tornado will be the primary threats with the stronger
storms. Conditions are being monitored for the need of a possible
WW.
DISCUSSION...MRMS mosaic radar imagery has shown a steady increase
in storm intensities over the past hour or so, with multiple
updrafts showing 30 dBZ cores extending into the 35-45 kft range.
The intensification of the storms is coincident with increased
diurnal heating across portions of central and southern GA, where a
southwesterly low-level jet continues to advect low-level moisture.
The expectation is for surface temperatures to heat well into the
70s F amid upper 60s to near 70 F dewpoints by late morning/early
afternoon, with MLCAPE likely exceeding 1500 J/kg. RAP forecast
soundings depict relatively steep 0-1 km lapse rates, overspread by
6.5-7.5 C/km lapse rates in the low to mid-levels. As such,
efficient downward momentum transport may support a few damaging
gusts.
Within the past hour, a transient supercell may have spawned a
tornado in Houston County, AL (based on a possible TDS shown on KEOX
dual-polarimetric radar data). While an additional tornado or two
remain possible through the day, current regional VADs and RAP/NAM
forecast soundings depict modestly sized/curved low-level
hodographs, with a weakness noted in the 850-700 mb layer, driven by
the departure of the low-level jet. As such, the tornado threat may
be tempered by decreasing deep-layer ascent. Nonetheless, the
overall severe threat may be prevalent enough that a WW may be
needed.
..Squitieri/Hart.. 03/25/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CHS...CAE...JAX...FFC...TAE...
LAT...LON 31178483 31748434 32498375 32878330 33078289 33098252
32928197 32618168 32008160 31348186 30968242 30818333
30728428 30768460 31178483
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MD 0338 CONCERNING HEAVY SNOW FOR EASTERN WISCONSIN AND NORTHERN MICHIGAN
Mesoscale Discussion 0338
NWS Storm Prediction Center Norman OK
0854 AM CDT Sat Mar 25 2023
Areas affected...Eastern Wisconsin and northern Michigan
Concerning...Heavy snow
Valid 251354Z - 251800Z
SUMMARY...Heavy snowfall rates on the order of one to two inches per
hour are expected to continue across eastern Wisconsin into northern
Michigan through the early afternoon hours.
DISCUSSION...Over the past 1-2 hours, multiple surface observations
from eastern WI and northern lower MI have reported falling snow
with visibilities at or below 1/4 mile. Given temperatures largely
in the low 30s and wind speeds between 10-15 knots, blowing snow
probabilities are sufficiently low to imply that the visibility
reductions are largely the result of heavy snowfall rates.
Furthermore, the lowest visibilities have been co-located with a
persistent organized snow band from eastern WI to the northern
portions of Lake Michigan, which further implies that heavy snowfall
is ongoing with rates as high as 1-2 inches per hour.
These observed trends are expected to persist at least through the
remainder of the morning. Dynamic lift associated with the left-exit
region of an upper jet, coupled with strong isentropic and
frontogenetical ascent in the 850-700 mb layer, will reside over the
region as a compact upper low, currently over north-central IL,
translates east into the lower Great Lakes region. Organized snow
bands will remain possible with snowfall rates as high as 2 in/hour
at times. Locations across northeast lower MI with temperatures
currently above freezing will likely see a transition from a mixed
precipitation type to mainly snow through the late morning as
low-level saturation/evaporative cooling allows for falling
temperatures closer to freezing.
..Moore.. 03/25/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...APX...GRR...MQT...GRB...MKX...
LAT...LON 43708665 43618682 43548719 43418742 43208771 43008801
42938834 42918863 42948892 43058903 43258914 43638897
44188870 45568773 46028721 46408663 46678584 46798514
46698454 46508414 46238366 46018342 45768323 45088332
44578424 44248493 44048548 43708665
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Public Severe Weather Outlook
PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0848 PM CDT FRI MAR 24 2023
...Severe thunderstorms expected over parts of the northern
Mississippi into adjacent parts of northern Alabama and middle
Tennessee overnight...
* LOCATIONS...
Northern half of Mississippi
Southwestern Tennessee
Northwestern Alabama
* HAZARDS...
A few intense tornadoes
Scattered damaging winds, some hurricane force
* SUMMARY...
Scattered severe thunderstorms are likely across parts of the
lower Mississippi Valley and Tennessee Valley tonight. Several
tornadoes are possible, including the possibility for a few
strong tornadoes, and scattered damaging gusts.
Preparedness actions...
Tornadoes at night can be particularly dangerous because they
are usually fast-moving and difficult to see. Stay tuned to
NOAA Weather Radio, weather.gov, or other media for watches and
warnings. A tornado watch means that conditions are favorable
for tornadoes to form during the next several hours. If a tornado
warning is issued for your area, move to a place of safety,
ideally in a basement or interior room on the lowest floor of a
sturdy building.
&&
..Smith.. 03/25/2023
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SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Sat Mar 25 2023
Valid 251300Z - 261200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS UPPER OH
VALLEY/LOWER GREAT LAKES AND THE SOUTHEAST...
...SUMMARY...
Isolated severe thunderstorms are possible across parts of the Upper
Ohio Valley and Lower Great Lakes between about 1 to 5 PM EDT.
Multiple rounds of isolated severe thunderstorms are expected across
parts of the Southeast through Sunday morning.
...Upper OH Valley and Lower Great Lakes...
A vigorous mid-level shortwave trough centered over IL will rapidly
progress across the Lower Great Lakes through this evening. The
trailing southeast portion of strong large-scale forcing for ascent
should initially overlap a destabilizing air mass over OH towards
midday. At least isolated low-topped convection should develop as
meager buoyancy develops with MLCAPE of 200-500 J/kg. Despite veered
low-level winds, very strong speed shear will support potential for
a few discrete, low-topped supercells. Setup appears most likely to
yield a marginal threat of all severe hazards for a few hours around
peak heating from eastern OH and northern WV into western PA and
southwest NY.
...Southeast...
Below-average confidence exists in severe potential amid multiple
rounds of thunderstorm possibilities through the period within
relatively nebulous large-scale ascent.
Morning to afternoon severe potential should be focused ahead of a
lingering arc of convection from central GA to southeast AL, as
low-level warm theta-e advection occurs from the west towards the
GA/SC coast. Although much of the large-scale forcing for ascent
will be displaced to the north of the region, the low-level
moistening in conjunction with pockets of stronger diurnal heating
should support an uptick in storm intensity. Veered low-level flow
but adequate deep-layer shear could yield a few weak supercells with
an isolated severe threat.
Beginning this evening and persisting overnight, modest low-level
isentropic ascent is anticipated along a quasi-stationary front from
the southern Lower MS Valley through central GA. Ample PW will exist
south of this baroclinic zone within a plume of steep mid-level
lapse rates emanating from northeast Mexico across much of the
northern Gulf. This will yield a corridor of moderate buoyancy
persisting well into the overnight. The 00Z ECMWF and 06Z HRRR are
most insistent on convective development, especially during the
early morning along the front. Deep-layer shear profiles will
conditionally favor a threat for a few supercells with large hail as
the most probable hazard.
..Grams/Goss.. 03/25/2023
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