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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, August 5, 2023

SPC Aug 5, 2023 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1127 AM CDT Sat Aug 05 2023 Valid 051630Z - 061200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN COLORADO INTO SOUTHERN KANSAS AND NORTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN A SEPARATE AREA FROM EASTERN ILLINOIS INTO CENTRAL AND SOUTHERN PARTS OF INDIANA... ...SUMMARY... The most concentrated area of severe thunderstorms with potential for destructive wind and hail is expected across parts of the south-central Great Plains from mid-afternoon through tonight. Potential for a few tornadoes will exist separately over the Mid-Missouri and Wabash Valleys during the late afternoon to early evening. ...Synopsis... Water-vapor imagery this morning shows a rather complex upper-air pattern with several important features that will influence the severe threat this afternoon into tonight. An MCV located over the southeast KS/northeast OK vicinity will continue to move east across the Ozarks during the day. Another MCV over IL will gradually shift east into IN by this evening. A mid-level low will move little over SD during the period, while a belt of stronger mid- to upper-level flow associated with an upper jet noses into the central High Plains. In the low levels, extensive outflow is evident over much of the northern half of OK into KS in wake of earlier morning thunderstorm activity near the OK/KS border. Easterly low-level flow will aid in maintaining moist conditions into eastern CO southward to the Raton Mesa. A narrow moist plume will protrude northward from eastern NE/western IA into southeast SD ahead of a gradually eastward-moving cool front. Low-level confluence will aid in focusing thunderstorm development over the lower Wabash Valley beginning early this afternoon through early evening. ...Eastern CO/northeast NM into the TX Panhandle and KS/OK... Not much change from previous forecast thinking. Convective outflow late this morning arcs westward across central OK through the central TX Panhandle. Near and north of the outflow, late morning thunderstorms over OK may continue to linger into the mid afternoon across the northern half of OK and pose an isolated risk for severe gusts. The initial thunderstorm development and more appreciable severe risk will probably focus near the Raton Mesa and Palmer Divide towards mid-afternoon. Moist upslope flow beneath the left exit region of an upper jet overspreading the central High Plains will facilitate a favorable setup for supercells. Potential will exist for regenerative supercells spreading east-southeast off the higher terrain. A few of these may become long-lived and capable of producing baseball to softball-sized hail centered on the southeast CO vicinity given highly elongated mid to upper hodographs and large buoyancy amid very steep mid-level lapse rates. A strengthening low-level jet over west TX during the evening will favor increasing convective development with multiple severe thunderstorm clusters spreading across western and southern KS, the Panhandles, and western to northern OK. Severe wind gusts will become more prolific as this occurs, which should include potential for sporadic gusts from 70-85 mph. ...Ozarks/Mid South... Ongoing thunderstorm cluster late this morning will continue to move east into a destabilizing and very unstable airmass across northern AR. Strong heating via mostly clear skies will result in temperatures warming into the 90s with mid to upper 70s dewpoints. Forecast soundings show a moderate mid-level flow enhancement via the approaching disturbance and MLCAPE 3000-4500 J/kg. Although uncertainty is high regarding details, it is possible some rejuvenation to the thunderstorm activity occurs on the periphery of the deeper cores going forward into the early-mid afternoon. If this occurs, widely scattered strong to severe gusts are possible into the early evening. ...Mid-MO Valley vicinity... A mid-level low over central SD will drift east with stronger destabilization confined downstream of it from southeast SD to eastern NE and far western IA. Early afternoon convective development will initially be most pronounced across southeast SD and likely arc southward into at least northeast NE before spreading into northwest IA later. Weaknesses in the mid-level wind profile may yield a linear cluster type mode, but some enlargement to the low-level hodograph, especially in the SD/NE/IA border area, should foster low-level updraft rotation capable of producing a couple tornadoes. Otherwise, slow-moving linear clusters will yield a threat for isolated severe hail and wind persisting through the evening. ...IL/IN vicinity... An MCV over central IL will drift east into IN through tonight. Continued destabilization despite appreciable cloud cover will become increasingly conducive for scattered storms to develop by early to mid afternoon. Forecast soundings show a spatially confined corridor of favorable low-level SRH overlapping the northeast extent of the surface-based instability plume in southern parts of IL/IN. A few supercells will probably evolve as storms mature through the late afternoon/early evening and move east into south-central IN. Any vigorous updraft/supercell will be capable of at least an isolated, short-term risk for a tornado given the wind profile/moist low levels. ..Smith/Squitieri.. 08/05/2023 Read more CHECK UPDATE ZOOM GRAPHIC
SUNRISE AND SUNSET TIMES IN UTC (if you're not logged in to Google)
CHICAGO UTC-6 during CST (Central Standard Time, e.g., winter)
CHICAGO UTC-5 during CDT (Daylight Savings Time, e.g., summer)