There seems to be three distinct categories setting up.
But as always, things are subject to change.
Here we go! A Tornado Watch has been issued for most of Indiana until 9:00PM
It makes sense. The second line of storms is forming in Illinois.
Tornado Watch
TORNADO WATCH OUTLINE UPDATE FOR WT 195 NWS STORM PREDICTION CENTER NORMAN OK 225 PM EDT TUE MAY 7 2024 TORNADO WATCH 195 IS IN EFFECT UNTIL 900 PM EDT FOR THE FOLLOWING LOCATIONS INC005-007-011-013-015-017-021-023-027-039-045-049-053-055-057- 059-063-067-069-071-073-081-083-085-087-089-091-093-095-097-099- 101-103-105-107-109-111-113-119-121-127-131-133-141-145-149-153- 157-159-165-167-169-171-181-183-080100- /O.NEW.KWNS.TO.A.0195.240507T1825Z-240508T0100Z/ IN . INDIANA COUNTIES INCLUDED ARE BARTHOLOMEW BENTON BOONE BROWN CARROLL CASS CLAY CLINTON DAVIESS ELKHART FOUNTAIN FULTON GRANT GREENE HAMILTON HANCOCK HENDRICKS HOWARD HUNTINGTON JACKSON JASPER JOHNSON KNOX KOSCIUSKO LAGRANGE LAKE LAWRENCE LA PORTE MADISON MARION MARSHALL MARTIN MIAMI MONROE MONTGOMERY MORGAN NEWTON NOBLE OWEN PARKE PORTER PULASKI PUTNAM SHELBY ST. JOSEPH STARKE SULLIVAN TIPPECANOE TIPTON VERMILLION VIGO WABASH WARREN WHITE WHITLEY
Be alert for severe weather today and for the next 48 hours. (5/7 - 5/8)
If you have a weather radio, make sure it's on and has fresh batteries. If you don't have a weather radio, you should buy one along with some batteries. Today and tomorrow should be rough and then it's all over by Thursday. Friday will be sunny with a high of 64 and the low will be 48. Isn't that nice?
The Plains States got hit really hard last night. One person is dead and there's a lot of destruction.
For us here in Indiana, a large bow echo is forming right at the Illinois-Indiana border.
I expect the National Weather Service to put out a severe thunderstorm watch at some point and maybe even a tornado watch. Here what they are saying for now:
Area Forecast Discussion National Weather Service Indianapolis IN 618 AM EDT Tue May 7 2024 .KEY MESSAGES... - Severe storms expected today, especially during the afternoon and evening. All forms of severe hazards are possible. - Additional severe storms are possible Wednesday afternoon and evening. All forms of severe hazards are again possible. - Heavy rain is possible at times through Wednesday night. Localized flooding will also be possible. - More chances for thunderstorms mainly Thursday and Saturday. - Normal to slightly below normal temperatures from Thursday into early next week. && .FORECAST UPDATE... Issued at 617 AM EDT Tue May 7 2024 With the main line of convection still well to the west over west central Illinois, slowed down PoPs a bit. The ETA of the line into the Wabash Valley has been pushed back to 13z per AWIPS distance speed tool. Expect the line to weaken substantially with little to no instability to work with per LAPS data. && .SHORT TERM (Today and tonight)... Issued at 245 AM EDT Tue May 7 2024 Tuesday Rd #1 | Strong but Mostly Sub-Severe | Between 9AM and 12PM An ongoing MCS over MO will progress eastward overnight, propelled by a strong LLJ. As this reaches the Ohio Valley this morning, the LLJ will begin to wain, remaining stronger further west. Still, sufficient 0-3km CAPE between 100-150 J/kg, and a sustained cold pool should be enough to keep the MCS ongoing despite weaker LL dynamics. The expectation is for this MCS to be over Indiana between 9AM and 12PM. Atmospheric disorganization and a lull in thermodynamic availability will be the main mitigating factors for severe convection within this initial round. An elongated low to the north will keep deep layer shear elevated over the northern half of central Indiana, but mid level lapse rates and theta-e advection ahead of the MCS will be much weaker. The opposite will be true for the southern half of central Indiana (Elevated Instability, but Weak Shear). This should cause the storms over northern central Indiana to become more shear dominant, with convection outrunning the UDCZ. For this reason, the northern section of the line may briefly be near severe criteria as it nears/enters Indiana, but should quickly weaken as it progresses eastward. The southern half of the storm then becomes the greater concern depending on how quickly the cold pool moves eastward. Its possible the cold pool becomes dominant on the southern half, and the main concern then shifts towards initiation along the outflow boundary. However, if balance does remain, there is high enough 0-3km CAPE, and theta-e ingestion for potentially severe wind gusts along the UDCZ for this first round. Tuesday Rd #2 | Scattered Severe Storms | Between 3PM and 10PM Even though this is round 2 of convection for the day, the storm mode and overall hazards will likely not be the same over the entire 7 hour threat period. For that reason, I am going to split this portion of the discussion into 2a (3P-7P) and 2b (6P-10P). Round 2a (3P-7P): The remnants of the morning convective line will be moving away by early afternoon with a capped lower level for portions of the late morning and early afternoon. Any cap that does form will quickly erode as rapid theta-e advection pushes a warm, moist layer over central Indiana this afternoon. Broad diffluence of the mid/upper level jet streaks along with this rapidly destabilizing atmosphere should lead to scattered CI over central Indiana around mid-afternoon. Early on, multicellular clusters will be the more common storm mode as overall parameter spacing remains moderated by sufficient, but weak 800-700mb winds, and weak anvil level flow. Current expectations for this initial time period are for 0-1 SRH to be around 100, with CAPE beginning around 1500 J/kg. Effective shear will still be plenty strong for updraft organization within multicells, and an isolated wind and hail threat is likely. Poor precip dispersion aloft within weak anvil level flow, may lead to precip loading in the updraft, creating more sub-severe and melting hail, but confidence is not high in this solution given robust effective bulk shear. Round 2b (6P-10P): The second half of this round looks to be the most potent portion of the entire day. A pressure trough will begin to develop across central Indiana late this afternoon into the evening providing another source of lift and convective organization. Shear vectors along this pressure trough remain orthogonal keeping the storm mode mostly discrete. During this time period, mid level lapse rates ramp up even further, pushing SBCAPE values near 3000 J/kg. This along with better anvil level flow, and a strengthening LLJ will likely lead to the formation of supercells. This time period will be most concerning for areas along and east of the I-69 corridor including the cities of Muncie, Indianapolis, Bloomington, Shelbyville, Columbus, Rushville, Winchester, and Seymour. With the expectation of supercells during this time period, all severe hazards are on the table. Strong 0-1km lapse rates, 0-1km shear and low LCLs also intensify the tornado threat for this time period, including the potential for a few strong tornadoes (EF2+). Giant hail (2.5"+) will also be possible within strong updrafts of supercells. && .LONG TERM (Wednesday through Monday)... Issued at 245 AM EDT Tue May 7 2024 Wednesday and Wednesday night... A severe weather outbreak followed by heavy rain and flooding are possible Wednesday afternoon and night as a surface low heads northeast towards central Indiana in the fast southwest flow aloft around the base of the High Plains upper low. This will allow a warm front to lift northeast from southern Indiana to near the I-74 corridor by late afternoon. By Thursday morning, the associated surface low will be somewhere near Muncie with a cold front sweeping through from the west. Out ahead of the cold front and in the warm sector to the south of the northeastward moving warm front, the atmosphere will destabilize during the afternoon with CAPEs in excess of 1000 J/kg. The combination of the instability, strong mid level shear in excess of 50 knots and the synoptic forcing will likely lead to rapid thunderstorm development during the afternoon with all modes of severe storms possible. Model soundings are afternoon curved hodographs with 0-3 km SRH near 200 and 0-1 km SRH slightly over 100. The biggest caveat to severe weather potential across central Indiana will be how far northeast the warm front gets during the afternoon and if discrete cells can form ahead of a likely MCS approaching from the southwest. If the front doesn`t it make it as far northeast, and the 00z runs are hinting at this scenario, severe weather will likely be limited to our southwestern counties. This has prompted a further southwest shift in the SPC Day2 severe outlook, which has the Enhanced Risk south of Terre Haute and Greensburg and the Slight Risk only as far north as Cicero and Anderson. FWIW, CAMs favor the bulk of the MCS to move south of I-74 with little to no discrete cells ahead of it. Still, with uncertainty, will continue with 80+ percent PoPs over all central Indiana Wednesday night with 50 percent PoPs Wed afternoon over southwestern counties tapering to 20 percent northeast. By nightfall, the focus will shift more towards heavy rain and flooding as PWATS increase to 1.5 inches or higher which is the max moving average for this time of year. In addition, coupled jet structure from jet maxes over the Great Lakes and southern states, could enhance rainfall totals. DESI suggests an inch or more 24 hour QPF is possible over south central Indiana and this looks to be on the low side. Will make mention of heavy rain and flooding potential in the HWO and in web site and social media graphics. Thursday night through Tuesday... A pair of upper waves in northwest flow aloft will bring decent chances for convection to the area Thursday and again Saturday. Otherwise, signal lacking for anything other than low chances for convection for the rest of the weekend due to general troughy flow aloft. Meanwhile, models are hinting at an approaching upper ridge early next week which would tend to bring dry weather. Temperatures look to be more on the cool side than recently with normal or slightly below normal afternoon highs in the 60s and 70s.
NWS: A Major Severe Weather Outbreak is Forecast Today and/or Tonight
Please read the National Weather Service's Public Severe Weather Outlook.
https://www.spc.noaa.gov/products/outlook/pwo.html
See also The Storm Prediction Center:
Prepare for severe storms in Indiana and the entire central USA!
Indiana will see a chance of strong to severe storms on both Tuesday and Wednesday. If you have family living in Kentucky or Oklahoma, be sure and give them a call to warn them. Tornadoes are likely in those states and they should probably get a hotel in another state until the storms pass.
Here is what the National Weather Service is thinking about Indiana:
LONG TERM (Tuesday Night through Monday)... Issued at 305 PM EDT Mon May 6 2024 Late Tuesday night through Wednesday night... A break in convection is expected to start late Tuesday night, with even weak ridging building into central Indiana from the subtropical surface high pressure to our southeast. Despite clearing skies, lighter southwesterly breezes will hold dewpoints in the upper 50s...resulting in low temperatures around 60F across the region. Wednesday will bring another favorable set-up for convection and perhaps widespread severe weather with a warm frontal type boundary likely slowly advancing northward near our southern counties ahead of a strengthening surface low slowly approaching over the Middle Mississippi Valley. Much of the day Wednesday may be the quiet before the storm as the narrow ridging between the two systems continues to cross the CWA...albeit eventually self-destructive with the bright skies bringing low 80s and light southerly winds holding dewpoints in the 55-65F range. Resultant CAPE by 21Z should range from 1000-3000 J/kg from north-south...including moderately strong 7- 8 deg/km lapse rates over most of the area. Widespread 40-55 kt 0-6 km shear will also support arriving/developing convection. So far appears most likely storm pattern will be a mesoscale convective system initiating in the afternoon somewhere in the central/eastern Illinois region...before tracking eastward into Indiana during the late day/early evening hours. This would likely transition into more of a heavy rain/flooding threat later in the evening and into overnight hours, especially south of I-70 amid the system`s warm sector`s anomalous precipitable water values approaching 2.00 inches. While the environment would support discrete cells ahead of a later MCS arrival...organized severe weather`s location would be dependent on warm frontal position, with timing likely determined by where/when storms begin to fire to our west. All severe hazards are on the table for PM hours Wednesday with damaging winds and large hail the greatest threats during the afternoon/evening...and flooding the greatest concern for the evening/overnight. Although it is only early May, the set-up and potential are perhaps more indicative of a June pattern with the synoptic set-up able to effortlessly fuel ample deep moisture into central and especially southern Indiana. Rain chances will drop from west to east late Wednesday night as the supporting surface low crosses the state. Total 24-hour rainfall potential for Wed-Wed night will be 1.00-2.50 inches along/south of the I-70 corridor, with less than 1.00 inch expected for most locations north of I-70. Temperatures will be above normal amid the S/SW flow and overall warm sector of the passing/approaching systems. Expect low 80s ahead of convection Wednesday...while lows Wednesday night amid decreasing chances of rain ranging from the upper 50s near Lafayette to the mid 60s south of the I-70 corridor. Thursday through Monday... The last five days of the long term will then trend to at least a couple northern stream, positively-tilted short waves cycling from the northern Plains into the Midwest. Not the greatest certainty with this pattern, with some guidance members originally hinting at the second wave plunging and inducing a strong baroclinic circulation near the Ohio Valley around the Sunday/Monday timeframe ...however, latest data now suggests amplification will be more modest, which should keep the pattern more progressive over the region thru the end of the long term. This should translate to near to slightly below temperatures amid west-northwesterly breezes. Thursday will be marked by robust to gusty breezes as the gradient from the combination of departing low pressure and the passage mid-level supporting vort. The 5-day period will include several chances for at least stray showers under the troughy flow...with more organized showers expected both Thursday and Saturday per corresponding short waves. Widespread and/or heavy rainfall could be possible early next week should the weekend wave plunge and phase, although currently low chances in this set-up coming to fruition. The normal max/min at Indianapolis through the long term is 72/52.
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