Temps | Gusts | WU KORD KPWK

CLICK for this month's BIG night sky ...




Cardinal SAT


MOBILE DEVICE? Turn sideways. Weather conditions directly above are near Lakefront. Top tabs refer to O'Hare (official).

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.


Thursday, March 30, 2023

SPC Mar 30, 2023 Day 4-8 Severe Weather Outlook

LIVE MAP (ABOVE) ... Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0337 AM CDT Thu Mar 30 2023 Valid 021200Z - 071200Z ...DISCUSSION... A mid/upper shortwave trough located over the southern Rockies Day 4/Sunday morning will weaken as it develops east across OK/TX. Southerly low-level flow will modestly increase and begin to transport Gulf moisture northward across east TX toward southeast OK and the Arklatex vicinity ahead of a dryline. Sufficient vertical shear will exist for organized convection. However, questions remain regarding moisture quality/timing and northward extent, and at least modest midlevel capping. If current model trends continue and/or indicate better quality moisture, low-end severe probabilities will likely become necessary in the Day 3 outlook. A large-scale upper trough will dig across the western states on Day 5/Monday. Stronger height falls spreading east toward the Rockies will result in lee cyclogenesis and increased southerly low-level flow across the southern Plains and south-central states. This will transport Gulf moisture northward through the period, with a broad warm sector developing ahead of a dryline from central OK/TX eastward to the Mid/Lower MS Valley by Day 6/Tuesday. While some stronger southwesterly deep-layer flow will overspread this developing warm sector on Monday, large-scale ascent will remain displaced to the west. Furthermore, capping will likely limit convection in the absence of stronger ascent. Some conditional severe threat could develop, but confidence is too low to warrant a 15 percent delineation on Monday. As the western trough ejects on Day 6/Tuesday, potential significant severe thunderstorms will be possible far eastern OK toward southeast MO and vicinity. Rich boundary-layer moisture will be in place amid steep midlevel lapse rates courtesy of an EML advecting across the region from the Mexican Plateau. This will supply plenty of instability with stronger vertical shear accompanying the ejecting trough. There is some uncertainty among medium range guidance on the northern extent of better moisture return and hence severe potential. This is mostly driven by differences in surface low, dryline and warm front positions related to somewhat different ejection of the upper trough. However, guidance is in very good agreement with respect to the southern portion of the risk area. Supercells capable of all severe hazards, some potentially significant, will be possible. By Day 7/Wednesday, some severe potential could persist ahead of the eastward-advancing cold front across portions of the Midwest. However, the upper low/trough is forecast to quickly lift northeast into Canada and large-scale ascent will be waning. Still, a seasonally moist boundary-layer will exist ahead of the front amid strong vertical shear. Depending on trends, severe probabilities may become necessary in subsequent outlooks. Lower-amplitude flow will overspread much of the CONUS east of the Rockies by day 8/Thursday and a broad area of surface high pressure will bring mostly dry and stable conditions. The exception may be across parts of the Mid-Atlantic coast toward the Southeast ahead of the eastward-advancing cold front. However, nebulous forcing and modest shear likely will temper severe potential. 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)