BBS: TELESC.NET.BR Assunto: DAY1SVR: Day 1 Convective Outlook De: COD Weather Processor Data: Thu, 26 Mar 2026 20:02:25 +0000 ----------------------------------------------------------- ACUS01 KWNS 262002 SWODY1 SPC AC 262000 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Thu Mar 26 2026 Valid 262000Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM CENTRAL ILLINOIS EASTWARD INTO INDIANA...OHIO...AND EXTREME WESTERN PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms are expected late this afternoon and evening across parts of the Midwest and Ohio Valley. Large to very large hail, a few tornadoes, and damaging winds will all be possible. ...From northern MO across IL, IN, OH and into western PA... The air mass continues to heat and destabilize this afternoon ahead of a cold front, which extends from southern Lower MI westward toward the MO/IA border at 20Z. The air mass remains capped for surface-based parcels, but clouds will continue to develop along the boundary with eventual severe storm development along and behind much of the front. Stronger heating / larger temp-dew spreads suggest a lesser tornado risk for western areas, while farther east conditions appear a bit more favorable with more low-level SRH / with lake breeze effects. GPS water vapor sensors also show higher values of PWAT over southern IN and KY which will lift northeastward across IN/OH/PA later today. In all areas, steep lapse rates aloft and strong deep-layer shear beneath northwest flow aloft will support supercells producing damaging hail. This may occur in both elevated cells north of the undercutting front, and ahead of it. For more information see mesoscale discussion #0291. ..Jewell.. 03/26/2026 .PREV DISCUSSION... /ISSUED 1108 AM CDT Thu Mar 26 2026/ ...Mid Mississippi Valley into the Midwest/Ohio Valley... Water-vapor imagery late this morning shows a flattened upper ridge centered over the south-central U.S. with strong westerly mid/upper-level flow across the Midwest/Great Lakes. A mid-level shortwave trough over the northern Rockies will move quickly east-southeast into the Upper Midwest and act to suppress mid-level heights across the Midwest/Great Lakes through tonight. Surface analysis this morning showed a weak low over eastern IA with a west-east oriented frontal zone extending east across the southern Great Lakes. If a weak surface reflection is maintained and develops east across the southern Great Lakes through this evening, it may notably influence severe potential within a focused corridor late this afternoon through this evening. The aforementioned front will gradually push south and serve as the primary impetus for storm development. Beneath a capping inversion, moistening will continue with surface dewpoints rising into the 56-62 deg F range from the mid MS Valley east into western PA. Upwards of 500-1500 J/kg MLCAPE is likely by mid afternoon south of the front. A belt of strong, westerly 50-65 kt 700-mb flow is forecast to move from IA and expand spatially across the warm sector through early evening. This increase in flow will act to elongate hodographs despite mainly veered southwesterly surface flow. Recent convection-allowing model guidance varies considerably on the depiction of cellular versus mostly linear clusters evolving in the first few hours of the convective life cycle. Time-lagged HRRR would imply a more spatially and numerically extensive supercell hail and tornado risk than most of the 12z HREF HRW members showing less risk of these hazards. The tornado risk could focus with potential supercells near a weak low and where surface flow would locally back to southerly. However, confidence is muted regarding this specific scenario. Regardless, current expectations are for thunderstorms to quickly develop along the length of the front from central IL eastward into IN, southern Lower MI, and northern OH by 19-22Z as diurnal heating erodes lingering convective inhibition. A mix of supercells and organized linear clusters will evolve with large to very large hail possible. A fairly quick transition to more linear structures appears likely given the frontal forcing, with an increasing threat for scattered to numerous severe/damaging winds as one or more clusters spreads east-southeastward across much of the OH Valley into western/central PA through the late afternoon and evening. Given the forecast strength of the low to mid-level flow, isolated gusts of 75+ mph may occur. There is a threat for a few tornadoes as well with both supercells and embedded mesocirculations within the linear clusters. Farther west across the mid MS Valley (MO into eastern KS), there is lower confidence in warm sector thunderstorm development this afternoon and evening due to the presence of a stronger cap. However, elevated convection may occur along/behind the cold front this evening, with strong deep-layer shear and sufficient MUCAPE conditionally supporting supercells with mainly a threat for large hail. $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: Capitol City Online (1:2320/107) ----------------------------------------------------------- [Voltar]