####018005355####
ACUS01 KWNS 062000

SWODY1

SPC AC 061959



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0259 PM CDT Sat Apr 06 2024



Valid 062000Z - 071200Z



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF

THE CENTRAL PLAINS...



...SUMMARY...

Severe storms remain possible across parts of the central into

southern Plains this afternoon and early evening. Scattered severe

wind gusts and isolated large hail are the primary risks with the

stronger storms, but a couple of tornadoes may also occur.



...20Z Update...

A band of low-topped convection currently arcs from the NE Panhandle

southeastward towards south-central NE and north-central KS. This

activity is occurring along/near a warm front, but with limited

low-level moisture. Strong low/mid-level flow associated with a deep

cyclone over the central High Plains should support continued

convective organization, with the primary threat remaining severe

wind gusts up to 75 mph. See Mesoscale Discussion 377 for more

details on the near-term severe threat across this area.



Additional thunderstorm development appears likely this afternoon

southward along an eastward-mixing dryline from parts of

north-central to south-central KS, and eventually central OK. Some

severe wind/hail risk will exist with any robust convection that can

be sustained, although shallow low-level moisture continues to be a

potentially limiting factor. Still, the better large-scale

ascent/forcing, and greater thunderstorm coverage, should remain

focused across KS where the Slight Risk is delineated.



Finally, a small westward expansion has been made to the Marginal

Risk across central OK. Latest visible satellite and radar trends

show attempts at convection occurring along the dryline across

north-central OK. Isolated thunderstorms should eventually develop

while posing a risk for marginally severe hail and strong to severe

wind gusts. See Mesoscale Discussion 378 for additional information

on the severe potential across OK this afternoon.



..Gleason.. 04/06/2024



.PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Apr 06 2024/



...Central/Southern Plains...

An increasingly negative-tilt mid/upper-level trough will overspread

the High Plains, with the upper jet exit region influencing the

central Plains as surface cyclogenesis occurs across northeast

Colorado/northwest Kansas into Nebraska through this evening. To the

south of the surface cyclone, a Pacific cold front will gradually

overtake a preceding dryline across the south-central Plains into

this evening. Modest early season low-level moisture (evident in

regional 12z soundings such as Norman/OUN, Fort Worth/FWD, Dodge

City/DDC, and North Platte/LBF) is expected to somewhat limit the

overall magnitude of today's severe risk, with a spatially narrow

corridor of warm-sector dewpoints generally limited to the 40s F

across Nebraska, some low/mid 50s F across Kansas, upper 50s F

across Oklahoma, and low 60s F relegated to north/central Texas, as

strong northward moist advection somewhat compensates for ample

diurnal mixing.



Even with low-level moisture/buoyancy limitations, very strong

large-scale ascent attendant to the ejecting upper-level trough will

aid in initial storm development early this afternoon near the

surface low/triple point vicinity across far northeast Colorado, far

northwest Kansas into western/central Nebraska, as well as other

parts of northern/central Kansas by mid/late afternoon. A few

low-topped supercells may occur before a transition to more linear

modes this evening. 



Storms that can acquire supercell characteristics would yield the

greatest threat for isolated large hail (1.0-1.5 inch diameter). 

While the tornado threat may tend to be limited by sparse low-level

moisture, sufficient low-level shear/SRH could support at least a

brief tornado threat with any stronger sustained supercell and/or

within a transitioning linear mode, especially in closer proximity

to the surface low over west-central/southern Nebraska and far

northern Kansas. It appears the predominant risk will be severe

gusts in the 60-80 mph range owing to steep 0-2 km lapse rates, very

strong boundary-layer flow, and a more linear mode over time.



While the primary severe risk is expected across parts of Nebraska

and northern Kansas, isolated severe potential will also exist in

vicinity of the dryline/Pacific front as it extends southward from

southern Kansas into central Oklahoma around peak heating. While

boundary layer moisture will be modest, isolated/widely scattered

thunderstorm development is expected toward/after sunset as far

south as I-40 in Oklahoma, and possibly as far south as the Red

River vicinity. That said, some forecast soundings (especially 12z

NAM but also HRRR) reflect some lingering mid-level

inhibition/subsidence that does not fully resolve early this

evening, especially with southward extent, which likely has

implications for the isolated nature of the development as well as a

less-than-typical early April potential for large hail. A few storms

could even develop late tonight in vicinity of the Pacific front

across central Texas toward the Hill Country.



$$