SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Aug 10 2023 Valid 121200Z - 131200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE LOWER AND MIDDLE OH VALLEY... ...SUMMARY... Severe thunderstorms are possible across portions of the lower and middle OH Valley on Saturday. ...Synopsis... Upper ridging is forecast to remain in place across the southern Plains and Southeast States on Saturday. North of this ridging, a belt of enhanced, broadly cyclonic upper flow will likely extend from the northern High Plains through the Upper Great Lakes and OH Valley into the Northeast. A low-amplitude shortwave trough will likely begin the period over the Upper Great Lakes, within this belt of stronger flow. This shortwave is expected to gradually move northeastward, while several vorticity maxima progress through its base. ...OH Valley into the Northeast... Surface low associated with this shortwave is forecast to occlude as it gradually shifts northeastward just ahead of the main wave, while an attendant cold front sags gradually southward across the OH Valley in its wake. The airmass across the OH Valley will likely be characterized by dewpoints in the upper 60s to low 70s, afternoon temperatures in the low to mid 80s, and moderate to strong buoyancy. An outflow boundary from preceding thunderstorms may extend across the lower and middle OH Valley, with this boundary and/or the cold front providing the impetus for afternoon thunderstorm development. This area will be on the southern extent of the stronger mid-level flow, resulting in moderate vertical shear and the potential for some organized severe thunderstorms. The cold front could also lead to the development of thunderstorms from the upper OH Valley across the Hudson Valley into southern New England, although guidance differs on the timing of this front as well as the quality of the moisture ahead of it. Some severe is possible in this area as well, but only low probabilities will be introduced given the aforementioned uncertainties. ...Southern/Central High Plains... Easterly low-level flow is expected to result in a corridor of slightly higher low-level moisture and buoyancy across southeast CO/northeast NM vicinity Saturday afternoon. High cloud bases and steep low-level lapse rates will favor outflow-dominant storm structures and the potential for upscale growth/cold pool amalgamation as the storms move into southwest KS and the OK/northern TX Panhandle. Some severe potential is possible with this convective evolution, but predictability of such an evolution is low at this forecast range, precluding the need for higher than 5% probabilities with this outlook. ..Mosier.. 08/10/2023
