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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, April 1, 2023

SPC Apr 1, 2023 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1240 AM CDT Sat Apr 01 2023 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE OHIO VALLEY AND NORTHEAST ALONG WITH THE SOUTHEAST... ...SUMMARY... Scattered strong-severe thunderstorms are expected across parts of the Ohio Valley and Northeast and over the Southeastern US. Wind, hail, and a few tornadoes are possible. ...Ohio Valley/Northeast... Upper low, currently located over western IA, is forecast to advance to southern Lake MI by daybreak, then into western NY by early evening. Strong 12hr height falls, on the order of 210m, will spread ahead of this feature across the OH Valley into the northern Middle Atlantic by the end of the period. Early this morning, several lengthy QLCS features are progressing across the OH/TN Valley region. This activity should surge into the central/southern Appalachians by sunrise, then gradually weaken as it approaches the Atlantic Coast by 18z. While a few strong storms may be noted with this convection, of more concern will be convection that develops immediately ahead of the cold front by late morning over the OH Valley. Latest model guidance suggests strong surface heating, along with cooling mid-level temperatures, will result in a fairly buoyant air mass by 16z across eastern OH. Scattered convection should easily develop ahead of the strongly forced front where deep-layer shear will support supercells. Very steep lapse rates will favor hail with this activity and there is some concern that very strong winds could mix to the surface, especially if a squall line matures. Wind probabilities currently reflect a less organized squall line; however, a mature surging squall line would pose a greater wind threat. Some consideration for higher wind probabilities may be warranted. Downstream, in the wake of the early-day convection, air mass will gradually moisten/destabilize as surface temperatures warm into the mid-upper 60s across eastern PA/DE/NJ. Forecast soundings suggest convective temperatures will be breached by 20-21z. Wind profiles strongly favor supercells and scattered storms should evolve across this region by early evening, especially as large-scale forcing overspreads this region. While storms may initially be somewhat discrete, an upward-evolving squall line will likely mature as it spreads toward southern New England. All hazards are possible with this activity across the Middle Atlantic. ...Southeast... Deep-layer flow will gradually become more westerly with time across the Gulf States as the strong upper low advances east across the OH Valley. This evolution will encourage pre-frontal convection that currently extends from middle TN-northern MS-northern LA to advance southeast through the period. While the primary large-scale forcing will spread well north of this region, deep-layer flow will be strong and organized line segments and clusters are expected. Additionally, a few supercells may also emerge within an elongated southeastward-moving cluster of convection. Damaging winds should be the primary concern, though some risk for a tornado or two can not be ruled out. ..Darrow/Thornton.. 04/01/2023 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)