Subj : DAY2 2/5 Risk Area Posted To : All From : Mike Powell Date : Sat Jul 04 2026 07:52:00 ACUS02 KWNS 040512 SWODY2 SPC AC 040510 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1210 AM CDT Sat Jul 04 2026 Valid 051200Z - 061200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE SUNDAY AFTERNOON AND EVENING ACROSS PARTS OF THE MID ATLANTIC... ....SUMMARY... Developing thunderstorm clusters may pose a risk for damaging wind gusts across parts of the Mid Atlantic and parts of the southern Great Plains Sunday afternoon and evening. ....Discussion... While ridging in the subtropical latitudes remains relatively suppressed, models indicate that the stronger mid-latitude westerlies will remain confined to the northern mid-latitudes through this period. Within this regime, a mid-level short wave trough is forecast to accelerate east of the Canadian Maritimes and New England early Sunday, before merging into a significant trough and embedded mid-level low digging across/southeast of the Labrador Sea. Upstream, mid-level troughing, including at least a couple of embedded smaller-scale perturbations, is forecast to continue progressing across and east-northeast of the Canadian Prairies. It appears that forcing with the lead impulse may support modest surface cyclogenesis across northern Saskatchewan through Manitoba. However, even with the trailing perturbation, it appears that forcing for ascent will generally remain focused to the north of the international border. To the south of the international border, models suggest that mid-level ridging, across the eastern Great Basin into north central Great Plains at the outset of the period, will expand across the middle Missouri Valley toward upper Mississippi Valley Sunday through Sunday night. Downstream, it appears that weak troughing, likely with a number of embedded convectively generated perturbations, will continue to overspread the middle Mississippi and Ohio Valleys through northern Mid Atlantic. To the east and south of this troughing, seasonably high boundary-layer moisture content may again become supportive of moderate to strong potential instability. However, given the generally weak nature of the large-scale flow and synoptic forcing, severe thunderstorm potential will largely be influenced by sub-synoptic developments with rather low predictability at this extended time frame. This continues to be reflected in sizable spread evident in convection allowing and related guidance. ....Mid Atlantic... There remains little general change from prior model output. It still appears that a low-level baroclinic zone could remain fairly well defined to the north and northeast of a surface low forecast to develop to the lee of the Blue Ridge by late Sunday afternoon. Both of these features could become a focus for vigorous thunderstorm development, though there appears a better signal in latest guidance for activity to form off the higher terrain into the lee surface trough, at least initially, before perhaps propagating along or just south of the remnant front toward coastal areas. Aided by a lingering modest, but weakening, belt of convectively augmented westerly flow, it is possible that one or two clusters could organize and become accompanied by better potential to produce damaging wind gusts late Sunday afternoon and evening. ....Southern Rockies into adjacent Great Plains... Uncertainty appears even greater than suggested in prior model runs, particularly with regard to whether there will become a well-defined boundary, supported by differential surface heating by late afternoon, to focus strong thunderstorm development. The higher terrain of the southern Sangre de Cristo Mountains into the Raton Mesa/ridge vicinity appears to offer the most probable focus for thunderstorm development by late Sunday afternoon. There is some signal that activity could consolidate into a cluster while propagating southeast of the higher terrain into a residual deeply mixed boundary layer over the high plains Sunday evening, accompanied by potential to produce strong wind gusts. ....Northwestern North Dakota... There remains a mixed signal within model output concerning potential destabilization and thunderstorm development along surface troughing extending south of the international border late Sunday afternoon and evening. With stronger mid/upper support likely to remain to the north of the border, the potential seems low, but low severe probabilities will be maintained, at least for now. ...Kerr.. 07/04/2026 $$ --- MultiMail/DOS * Origin: Capitol City Online (618:250/10) .