
Mesoscale Discussion 2240
NWS Storm Prediction Center Norman OK
0216 PM CST Sat Nov 29 2025
Areas affected...parts of the Midwest
Concerning...Heavy snow
Valid 292016Z - 300015Z
SUMMARY...Bursts of moderate to heavy snow are most likely to evolve
east/northeast from central Illinois across parts of
central/northern Indiana towards the Michigan/Ohio border into this
evening. Snowfall rates around 1 inch per hour are probable, briefly
near 2 inches per hour possible, before waning tonight.
DISCUSSION...Within a broad swath of snow across parts of the
Midwest, bursts of moderate to heavy intensity appear likely to
persist north of the mixed-phase region centered on southern IL.
This has been accompanied by early-afternoon lightning flashes in a
confined corridor into central IL. With the dendritic growth zone
centered around 550 mb, mid-level ascent is largely progged to be
stronger eastward within the mixed-phase precip swath closer to the
OH Valley. Bulk of guidance suggests ascent will wane after sunset
farther north as the leading shortwave impulse dampens. Until that
occurs, snowfall reduced visibilities from a quarter to half-mile
per Springfield, Lincoln, Decatur, and Champaign IL observations
should shift northeastward. This setup should support initial
snowfall rates of 1-2 in/hr, becoming more localized near 1 in/hr
later.
..Grams.. 11/29/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IWX...IND...LOT...ILX...
LAT...LON 40028869 40628774 41928549 42018475 41478432 40868466
39578615 39288769 39498839 40028869
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Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0348 PM CST Sat Nov 29 2025 Valid 011200Z - 071200Z Fire concerns are expected to remain low for the D3/Monday through D8/Saturday period. A series of troughs will bring cool and wet conditions across much of the CONUS. Less rainfall is expected across portions of the Southern High Plains. Some episodic overlap of windy/dry conditions may occur, particularly across the Texas and Oklahoma Panhandles into western Texas. However, confidence in the magnitude remains low. Periods of enhanced windy/dry conditions will also be possible across portions of Southern California, with periods of offshore flow behind storm systems. Overall, fuels in these regions remain fairly wet from recent heavy rainfall which should negate any fire weather concerns. ..Thornton.. 11/29/2025 ...Please see www.spc.noaa.gov/fire for graphic product...Read more

Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0149 PM CST Sat Nov 29 2025 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF EASTERN TEXAS INTO WESTERN LOUISIANA... ...SUMMARY... Isolated severe thunderstorms are possible across portions of east and southeast Texas into western Louisiana through tonight. ...20z Update... The previous forecast largely remains on track with only minor adjustments required - mainly removal of thunder probabilities across portions of OK/KS/MO where the mid-level vorticity maximum and surface cold front have already passed through. Across east/southeast TX, modest low-level moisture advection continues northward with temperatures warming into the upper 70s and low 80s for a few locations - a few degrees warmer than anticipated by high-res guidance. This additional heating combined with persistent, but shallow, convective showers across southeast TX lend confidence that at least a few attempts at deeper convection are likely by peak heating in the coming hours. Any appreciable tornado threat will likely be limited to near/along a diffuse warm frontal zone draped roughly from the Houston to Waco, TX area where low-level winds remain south/southeasterly. Further north near the DFW metro, deepening cumulus is noted in visible imagery where the surface cold front is impinging on the northern extent of appreciable MLCAPE. Thunderstorm development along the front appears likely in the coming hours, but the modest buoyancy profiles should modulate convective intensity. See the previous discussion for additional details. ..Moore.. 11/29/2025 .PREV DISCUSSION... /ISSUED 1024 AM CST Sat Nov 29 2025/ ...Central/East/Southeast Texas into Western Louisiana... A mid-level shortwave trough over the Plains this morning will continue to progress quickly east-northeastward today across the mid MS Valley/Midwest and OH Valley. A related surface low over eastern KS will likewise develop northeastward towards IL by this evening, with an attendant cold front sweeping south-southeastward across OK/TX and the ArkLaTex through tonight. Low-level warm/moist advection will continue to aid the northward transport of a partially modified Gulf airmass over portions of central/east TX and perhaps western LA. Thunderstorms should eventually develop by late afternoon/early evening along the front across north-central TX and vicinity, even though large-scale ascent will remain nebulous behind the departing mid-level shortwave trough. Filtered daytime heating will result in modest destabilization across the warm sector today, although mid-level lapse rates are not expected to remain modest. Sufficient deep-layer shear associated with a subtropical/southern branch of a mid/upper-level jet should support some updraft organization. Hail and strong/gusty winds may occur with the stronger cores that can develop and be sustained. But, the surging cold front will likely undercut convection fairly quickly. There also appears to be some chance for isolated thunderstorms to develop ahead of the front from parts of central into southeast TX late this afternoon. The large-scale forcing for ascent with southward extent will remain weak/nebulous at best, but low-level confluence may aid in convective initiation across this area. If these thunderstorms can develop, they would have access to greater instability and sufficient low-level shear to pose some threat for a tornado or two. However, the overall environment still supports maintaining a Marginal Risk given the departing shortwave trough and related large-scale forcing, modest lapse rates aloft, and tendency for the low-level flow to gradually weaken/veer with time through this evening and tonight.Read more

Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0133 PM CST Sat Nov 29 2025 Valid 301200Z - 011200Z ...NO CRITICAL AREAS... No changes are needed to the D2 Fire Weather Outlook. See previous text below. ..Thornton.. 11/29/2025 .PREV DISCUSSION... /ISSUED 0158 AM CST Sat Nov 29 2025/ ...Synopsis... Expansive surface ridging characterized by cool/cold surface temperatures will limit fire-weather concerns across the CONUS on Sunday. ...Please see www.spc.noaa.gov/fire for graphic product...Read more