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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.


Saturday, July 1, 2023

SPC Jul 1, 2023 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Sat Jul 01 2023 Valid 011300Z - 021200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE MID MS AND LOWER OH VALLEYS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE TN VALLEY/APPALACHIANS AND WEST CENTRAL TX... ...SUMMARY... Severe thunderstorms with swaths of damaging winds and large hail are expected later today into early tonight across the mid Mississippi and lower Ohio Valleys. More isolated severe storms will be possible farther east into the Appalachians and across west Texas. ...Mid MS and OH Valleys through tonight... A midlevel shortwave trough over the central Plains will progress eastward to the mid MS Valley by tonight, as embedded, convectively-enhanced perturbations rotate around its southern and eastern periphery. At the surface, the primary undisturbed warm sector resides from the Mid-South into southeast MO/southern IL/western KY this morning, with ongoing convection reinforcing rain-cooled air just south of I-70 across MO/IL into southwest IN. In the wake of the morning convection, the unstable warm sector will spread northeastward some across IL/IN/KY, where MLCAPE will increase to 2500-3500 J/kg during the day. Additional thunderstorm development is expected by mid-late afternoon across eastern MO near a weak surface cyclone and cold front, and storms will then spread eastward across IL and the OH Valley through tonight. Midlevel flow will increase to near 40 kt atop the warm sector, which will favor a mix of supercells and multicell clusters capable of producing damaging winds and large hail. There will be the potential for upscale growth into a larger cluster or line, with a corresponding threat for swaths of wind damage late this afternoon through late evening. The severe threat could persist into tonight across eastern KY/southern OH, assuming sufficient destabilization in the wake of today's convection over the OH Valley. ...Appalachians area through this evening... There is some potential for intensification of storms along residual outflows and/or a weak surface trough just east of the Blue Ridge, as the low levels warm/moisten through the afternoon. The stronger flow aloft will remain farther west, but moderate buoyancy could support clusters/line segments capable of producing occasional damaging gusts and marginally severe hail later today into this evening. ...West/southwest TX area this afternoon/evening... Weak convergence/ascent along a convectively-enhanced cold front, in combination with daytime heating/mixing, will likely support thunderstorm development near and east of the Davis Mountains and higher terrain in southeast NM. This area will remain south of the stronger midlevel westerly/northwesterly flow, but modest deep-layer shear and MLCAPE near 2000 J/kg will support storm clusters capable of producing a few severe outflow gusts and isolated large hail. ...PA/NY this afternoon/evening... Subtle/embedded perturbations will move over the lower Great Lakes region today, around the southern periphery of the midlevel low over the ON/QC border. Surface heating in cloud breaks and boundary-layer dewpoints well into the 60s will support MLCAPE of 1000-1500 J/kg from PA northward into NY (east of the influence of Lake Erie/Ontario). Lapse rates will not be steep, but some modest enhancement to mid-upper flow could be sufficient for a few semi-organized clusters capable of producing isolated wind damage for a few hours this afternoon/evening. ...Southern MT to northwestern ND this afternoon/evening... Though forcing for ascent will be weak, at least isolated thunderstorm development will be possible this afternoon/evening from edge of the higher terrain in southern MT northeastward along a weak pre-frontal trough. Surface heating/deep mixing will drive inverted-V profiles with MLCAPE at or above 1000 K/kg, and DCAPE near 1200 J/kg. Weak flow supports relatively slow-moving cells/clusters capable of producing isolated strong-severe outflow gusts. ..Thompson/Gleason.. 07/01/2023 Read more CHECK UPDATE ZOOM GRAPHIC
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