Severe Weather with all Modes of Hazards Possible!
Scattered severe thunderstorms are expected this afternoon through tonight across parts of the southern and central Plains.
Severe wind gusts, large to very large hail, and tornadoes are possible.
Are you prepared?
Now will be a good time to check your weather radios and have several ways to receive warnings
Severe Weather Outlook
…Southern Plains region…
Primary change to previous outlook has been to increase tornado probabilities across west central into northwest through north central TX area.
An old outflow boundary will persist in this region, but should become more diffuse with time. Several CAM runs and especially the HRRR continue to initiate storms in warm sector by late afternoon initially along the dryline across west central TX.
This initiation would be in advance of primary zone of forcing associated with the shortwave trough currently moving through northern Mexico.
While 0-1 km shear will initially be weak/modest, an increase in the low-level jet during the early evening within an otherwise favorable deep-layer shear environment will support potential for supercells with low-level mesocyclones, tornadoes and very large hail as storms move northeast toward central through northwest and north central TX this evening.
Otherwise additional storms will likely develop across west TX along retreating dryline during the evening and spread east through TX and OK during the overnight. The shear/instability parameter space will support organized storms with potential for linear/bowing segments as well as supercells capable of all severe hazards.
A strong shortwave trough will rotate northeast through AZ this afternoon accompanied by steep lapse rates and strong vertical shear. Though weak instability will remain a limiting factor, a few storms could pose a threat for mainly locally strong wind gusts and marginally severe hail.
…Tennessee through Ohio Valley region…
Strong vertical shear accompanying a shortwave trough has spread across TN and KY, but widespread showers/rain continue to limit overall destabilization potential. Will maintain a marginal risk for this region for now, but threat appears very conditional. –
SPC – Dial/Nauslar.. 03/18/2020
TOMORROW SEVERE WEATHER OUTLOOK
Severe thunderstorms are expected from the lower Missouri Valley and Ozarks vicinity into the middle Mississippi and lower Ohio Valleys on Thursday.
Damaging gusts, isolated large hail and tornadoes are possible, mainly during the afternoon into the evening hours.
A compact shortwave trough will eject northeast from the southern Plains to the Great Lakes on Thursday. As this occurs, intense deep layer southwesterly shear will overspread much of the Ozarks into the mid-MS and lower OH Valley vicinity while a deepening surface low develops east/northeast across KS to IA by 00z, to the Great Lakes/Canadian border by Friday morning.
Showers and thunderstorms may be ongoing Thursday morning in a strong warm advection regime across the mid-MS Valley and lower OH Valley. A warm front extending from the NE/KS border area east/southeast to near St. Louis to southern IN early Thursday will steadily lift northward through the afternoon.
By late afternoon/early evening, the surface low will be near the NE/IA/MO tri-state area with the warm front extending across central IA to near the WI/IL border eastward into northern IN/OH. A cold front will extend southward from the low into eastern OK and central/southern TX. 60s surface dewpoints will be common across much of the warm sector, with mid to upper 60s dewpoints possible from eastern OK/TX across the Ozark Plateau toward western KY/southern IL/MO Bootheel region.
Cloud cover across the region will inhibit destabilization somewhat, but steep midlevel lapse rates and increasing low level moisture will result in MLCAPE values increasing to 1000-1500 J/kg by afternoon. 850-700 mb southwesterly flow will likewise increase to 45-55 kt as the upper trough shifts eastward during the afternoon and evening.
Supercells will initially be possible ahead of the cold front, but may tend to grow upscale into bowing segments with time as deep layer shear will become more unidirectional into the evening hours.
Nevertheless, conditions will be favorable for damaging gusts, large hail and tornadoes across portions of the Ozarks into the lower Ohio Valley.
Further north near the surface low, effective SRH will be quite a bit stronger due to the influence of the deepening low and warm front.
Backed low level flow in this vicinity and better directional shear will result in a corridor of greater tornado potential during the late afternoon/evening. Large hail and damaging gusts will also be possible as supercells and bowing segment shift northeast toward southern WI/northern IL during the evening. ..Leitman.. 03/18/2020