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Weather conditions on bar directly above are near Lakefront. Tabs under Moon Phases refer to O'Hare (official).

Archives for SPC Convective outlook are updated daily with a live map a the beginning of the article. Touch or click map to get possible update, and follow link at end of article for referral to NOAA/NWS Storm Prediction Center. Archives for Chicago's hourly weather data were updated 24-48 hours after end of each day prior to Dec. 2020.

Tuesday, March 22, 2022

SPC Mar 22, 2022 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0237 PM CDT Tue Mar 22 2022 Valid 222000Z - 231200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS LOUISIANA...MISSISSIPPI..AND WESTERN ALABAMA... ...SUMMARY... A regional severe weather outbreak is expected across the Lower Mississippi Valley and middle Gulf Coast States today, with some threat continuing into tonight. Tornadoes, some of which are expected to be strong, and potentially widespread damaging winds can be expected. ...20Z Update... ...Portions of the Southeast and Central Gulf Coast... Line of thunderstorms currently extending from central MS southwestward into south-central LA continues to progress eastward. Northern portion of this line over MS has exhibited slightly faster eastward/northeastward motion than the portion farther south over south-central LA. The KDGX VAD did not sample a descending rear-inflow jet, suggesting that any surges within the northern portion of the line are a result of local downdrafts. This matches the overall reflectivity evolution noted thus far. This portion of the line is quickly moving into a less favorable thermodynamic. Recent mesoanalysis shows MLCAPE generally around 500 J/kg across east-central MS into west-central AL. This limited buoyancy and lack of larger scale organization suggests a somewhat limited severe potential with northeastern extent into more of northern AL. This matches previous forecast expectations with no changes needed. Farther south, the environment remains favorable for intense storms, but the convective mode has limited discrete storms thus far. 18Z LIX sounding sampled a very impressive wind profile amid thermodynamics that easily support deep convection. Any storms ahead of the line that can mature and organize should become supercells capable of all severe hazards, including tornadoes. Strong wind gusts and embedded tornadoes may also occur within the line as it moves through the area, particularly in any sections where updrafts/downdrafts cause forward surges. ..Mosier.. 03/22/2022 .PREV DISCUSSION... /ISSUED 1137 AM CDT Tue Mar 22 2022/ ...Lower Mississippi Valley/Middle Gulf Coast... A regional outbreak with tornadoes and widespread damaging winds is still expected to unfold across the region this afternoon. A composite quasi-linear convective system with embedded bow/LEWP structures continues an east-northeastward progression into west-central/southwest Mississippi and south-central Louisiana late this morning. This QLCS intercepts a northward-developing warm front that extends southeastward from west-central Mississippi into southeast Mississippi at this time. East of the QLCS, some increase in showers/thunderstorms has been noted across southeast Mississippi near the warm front. Expectations are that semi-discrete storms, at least on an isolated basis, are likely to develop ahead of the QLCS, such as the late-morning showers/few storms across southeast Mississippi, although the overall meridional pattern and warm sector cloud cover imply some lingering uncertainty in terms of the extent of free warm-sector development. Nonetheless, localized cloud breaks and minimal convective inhibition will support an increasing warm-sector risk, and with a further strengthening of low/mid-level winds and elongating hodographs, tornado potential is expected to further increase through the afternoon, which includes the potential for a few strong/intense (EF2+) tornadoes as well. A mesovortex or embedded supercell tornado risk, along with potentially widespread damaging winds, will otherwise readily exist with the QLCS and any development immediately preceding it. The overall severe threat should diminish during the evening through a combination of the northern portion of the QLCS outpacing surface-based instability and waning of large-scale ascent near the central Gulf Coast as the shortwave impulse ejects away from the region to the north-northeast. Nevertheless, a still strong low-level jet and presence of rich boundary-layer moisture will foster a persistent but probably spatially diminishing threat tonight across parts of Alabama and the western Florida Panhandle. Read more CHECK UPDATE ZOOM GRAPHIC