Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
SIG SEVERE
39,004
464,520
Grand Island, NE...Kearney, NE...Dodge City, KS...Hastings, NE...Hays, KS...
10 %
39,485
467,073
Grand Island, NE...Kearney, NE...Dodge City, KS...Hastings, NE...Hays, KS...
5 %
142,251
5,754,104
Oklahoma City, OK...Omaha, NE...Wichita, KS...Lincoln, NE...Topeka, KS...
2 %
97,534
9,520,082
Dallas, TX...Fort Worth, TX...Kansas City, MO...Tulsa, OK...Arlington, TX...
Probabilistic Damaging Wind Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
30 %
24,381
2,344,450
Richmond, VA...Newport News, VA...Hampton, VA...Grand Island, NE...Tuckahoe, VA...
15 %
169,632
13,376,476
Washington, DC...Virginia Beach, VA...Louisville, KY...Norfolk, VA...Lexington-Fayette, KY...
5 %
377,740
32,011,657
Dallas, TX...Fort Worth, TX...Baltimore, MD...Oklahoma City, OK...Kansas City, MO...
Probabilistic Large Hail Graphic
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
SPC AC 151630
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Mon Apr 15 2024
Valid 151630Z - 161200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL GREAT PLAINS AND CENTRAL AND EASTERN VIRGINIA...
...SUMMARY...
Scattered severe thunderstorms are likely across parts of the Great
Plains, beginning mainly this evening and continuing overnight.
Several tornadoes, large to very large hail, and damaging wind gusts
all appear possible. Strong tornadoes may occur this evening across
parts of Kansas and Nebraska. Scattered severe gusts are probable
this afternoon into the evening across portions of Virginia.
...Synopsis...
Water-vapor imagery this morning shows a large, closed upper cyclone
over UT with this feature ejecting over the southern/central Plains
tonight. A strong mid/upper-level jet will overspread much of the
southern/central Plains while a cyclone deepens over the High Plains
today. Southerly low-level flow will facilitate moisture return
northward concurrent with a warm front advancing northward across
the central Great Plains. A dryline is forecast to mix eastward
across the southern/central High Plains through peak afternoon
heating, before retreating westward this evening across parts of the
TX/OK Panhandles and western KS.
...Northern/Central Plains (Kansas/Nebraska/South Dakota)...
No appreciable change in thinking from the previous forecast in the
overall severe scenario for later today/tonight. Capping will
likely inhibit storm initiation over the northern/central Plains
through at least late afternoon. However, strong southerly
low-level flow will advect increasingly rich moisture northward with
upper 50s to low 60s surface dewpoints by early this evening across
the warm sector. Prior to storm initiation, 2000-3000 J/kg MLCAPE
is forecast concurrent with strengthening mid/upper-level flow.
Once convective initiation occurs (early evening), rapid supercell
development is expected as a LLJ intensifies. Large to very large
hail (around 2-3 inches in diameter) will be a threat with any
supercells that can form along/near the warm front, or southward
along the length of the dryline into western KS. Enlarged
hodographs during the evening will occur through midnight while some
additional increase in low-level moisture acts to counter increasing
CINH due to cooling surface temperatures. If a few discrete
supercells can maintain a feed of effective near-surface inflow
parcels, the tornado risk will likely become focused with those
storms. Given the strength of shear/buoyancy combination, strong
tornadoes appear possible this evening/tonight across portions of
KS/NE. As additional storms develop, an evolving cluster growing
upscale will potentially yield severe gusts, most likely from
north-central KS into central NE overnight.
...Southern Plains (Oklahoma/Texas)...
A lower coverage of storms is expected to develop farther south
along the dryline over parts of the southern Great Plains late this
afternoon into tonight. Ample mid to high-level clouds will tend to
limit daytime heating to some extent along the length of the
dryline. However, model guidance shows sufficient agreement in
depicting storm development across parts of northwest TX by late
this afternoon. Supercells appear likely with this activity given
strong (50-60 kt) deep-layer shear and large buoyancy. Isolated
large to very large hail will probably be the main threat with this
convection as it moves towards north-central TX. But, occasional
severe/damaging winds and perhaps a couple of tornadoes may also
occur through the early evening. Most guidance indicates any
supercells which develop will weaken with eastward extent as they
encounter increasing MLCIN, and become increasingly displaced from
the better large-scale ascent with the upper trough/low ejecting
over the central Plains. A highly conditional severe threat remains
apparent across OK late this afternoon and evening, with a favorable
parameter space to support supercells capable of producing all
severe hazards. But, much of OK may have a relative minimum in
convective activity until late tonight as a Pacific cold front
overtakes the dryline.
...Lower OH Valley into the Mid-Atlantic states...
Morning surface mesoanalysis places a residual frontal zone draped
over central IN/OH with a low-level moisture reservoir (low 60s deg
F surface dewpoints) extending from the confluence of the MS/OH
rivers northeastward into the lower Wabash Valley. Atop this
moisture, a plume of steep 700-500 mb lapse rates (8.0 to 8.3 deg
C/km) sampled at the Lincoln, IL and Wilmington, OH raob sites, will
overspread the OH Valley eastward into VA today. The richer
low-level moisture will likely remain west of the Appalachians
across the lower OH Valley where 1500-2500 J/kg MLCAPE is forecast.
Widely scattered thunderstorms are forecast to develop by mid
afternoon within the moist axis along/south of a stalled front over
the OH Valley. Effective shear 25-35 kt will support a mix of
supercells and organized line segments capable of hail and wind.
Farther east, steep lapse rates from the surface to 500 mb are
depicted in forecast soundings by early to mid afternoon (8 deg
C/km). Although PW will be lower across the Mid-Atlantic region, a
more deeply mixed boundary layer is forecast with strong westerly
mid-level flow (40 kt). Initial cellular storms will likely develop
over the higher terrain with subsequent development across northern
VA. A band of storms posing a risk for severe gusts (60-70 mph) and
resultant wind damage is forecast. Given the lapse rate profile
coupled with ample mid- to high-level flow and a linear mode, have
increased wind probabilities and an upgrade to level 3 categorical
outlook this update. The overall severe threat should gradually
diminish through late evening with the loss of diurnal heating.
..Smith/Bentley.. 04/15/2024
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