Severe storms possible Friday

(TULSA, Okla.) The main items of mention in this forecast will be thunderstorm potential and severity on Friday with the next upper wave to affect the region, and storm chances again early next week in association with a cold front in a continued northwest flow pattern aloft. A Slight Risk of severe thunderstorms will exist across portions of eastern Oklahoma and western Arkansas Friday afternoon and evening. The greatest threat will exist across areas southeast of I-44. The primary threats will be large hail to the size of ping pong balls and damaging winds to 60 mph. The shortwave trough that brought severe weather and locally heavy rains to Oklahoma and Arkansas Wednesday will continue to move away Thursday. Broad and fast cyclonic flow will stretch northwest down to Texas and then east along the Gulf Coast states. At the surface, weak low pressure over west central Arkansas will slide over toward the Mid-South while a cold front continues toward the Gulf Coast to its south and west. Higher dewpoint air, with readings in the 50s, remains in place over much of the central and southern Plains in the wake of the surface low and cold front, due to a lack of big pressure rises and a push of drier air from the west/northwest. Some showers may linger over northwest Arkansas Thursday morning on the back side of the departing upper wave. By afternoon, skies clear and temps will warm well into the 70s most places. Temperatures remain cold aloft as we remain under the influence of the broad upper trough over the continental United States. There are some indications of storms developing over the High Plains and tracking southeast in our direction, but this activity probably wouldn’t make it until after dark, with waning instability by this time. There is some potential for warm advection showers and storms after midnight, mainly over northeast OK. The Pac northwest system slides across the region on Friday, shower and storm chances will increase, especially across northeast Oklahoma and northwest Arkansas. The surface warm sector will still be suppressed to our south and will not have time to race north ahead of this system as it is following too quickly on the heels of Thursday’s departing wave. Despite this, the lingering moisture in place, as mentioned earlier, combined with cold temps aloft will still yield afternoon surface-based convective available potential energy, though cloud cover may limit this some. Deep layer shear will not be overly impressive but will be sufficient, especially the farther south you go, for some severe storms during the afternoon. Hail and winds will be the primary threats. A mean ridge in the West will be maintained going into next week, with some amplification of the pattern expected. A downstream shortwave trough will dig over the Midwest and Mississippi Valley and will force a cold front down the Plains on Tuesday. Moisture return will likely be sufficient by this time ahead of the front to yield a severe threat as the front works its way southeast across the region Tuesday afternoon and evening.