A squall-line at the western Indiana state line & a Tornado WATCH has been expanded to included most of Central/Southern Indiana until 12am.
A Severe T’Storm WARNING continues for Fountain, Parke, Vermillion, Puntnam, Vigo until 7:30pm. There have been 65mph wind reports in eastern Illinois with this line, but radar rotation has diminished.
Quick-moving line of storms nearly on top of the western state line at time of this posting. The entire line is covered with T’Storm and Tornado Warnings at this time and considerations are underway at the Storm Prediction Center to expand the Tornado WATCH to include the Indianapolis Metro area. Stay tuned:
The T’Storm Watch was replaced by a Tornado Watch as the line in Central Illinois continues to show embedded rotation, and currently portions of the line have Tornado Warnings. No change to the timing…7pm for the western state line, 8-9pm Indy metro and 10-11pm east-central Indiana. Rotation characteristics should diminish in more stable air east of Illinois, but can’t be ignored.
A Severe Thunderstorm Watch is in effect for areas in western-southwestern Indiana until 10pm, including Terre Haute, Sullivan, and Vincennes. A line of storms in Central Illinois continues to race quickly toward the western state line. We still expect this line to approach western Indiana between 6-7pm. It’s unclear if this line will be able to maintain severe thresholds after dark and with limited instability. Updates to come and we still anticipate this line (in whatever form) to move across the Indy metro between 8-9pm.
It’s just a waiting game now in Central Indiana, with an anticipated line of rain/storms forming along a strong cold front along the Mississippi River Valley. Initial discrete cells will gradually congeal into a solid line that will accelerate toward the state as low pressure strengthens.
We continue to target the time frame between 7pm-11pm for impact in Central Indiana. Much of the viewing area is under a Slight Risk for damaging wind, with an embedded tornado risk south of I-70 where temperatures are warmer and limited instability will be maximized.
Lates hi-res FutureTrak13 model data shows a target time for western Indiana around 7-8pm, the Indianapolis metro around 9pm, and eastern Indiana around 10-11pm. Due to limited instability, it’s possible this line has very little lightning associated with it…but even a line hefty showers may be sufficient to drag the robust wind field (>75mph) at 2,000-5,000 feet down to the surface.
Between now and then drizzle will be widespread, and the combination of melting snow and warm air aloft continues to produce very low visibility north of Indianapolis where snow pack is deeper. The flood threat remains high with another 1″-2″ rainfall possible this evening along and ahead of the cold front. It should be noted that wind and gusts will remain very strong post-frontal passage with a tightening pressure gradient field as this storm nears “bombogenesis” status.
The image below (via WxBell) shows the pressure gradient (packed “black” lines) and wind field at ~4,000 feet. These winds will occasionally “mix” down to the surface and produce gusts in excess of 45mph… which is why the Wind Advisory runs for most of Friday.
As mentioned many times this week, the warmth today is nothing more than a spring tease… with a return to an Arctic flow setting up next week. This will pose timing problems for quick-moving upper disturbances that may trigger some snow. The first of these features arrives sometime this weekend, possibly as early as Saturday afternoon. While the GFS and Euro show only minor amounts of show, it should be noted the Canadian model (which has a done a decent job of late) shows more appreciable snow (>2-3″) moving through Sunday.
It’s still very early in the forecast game and plenty of time to make any changes needed.
For now I’ll leave with cold hard facts in the latest 7 day forecast. Plenty of winter to endure as we truly earn our Spring Fever this year. Check for updates this evening right here on the blog – Sean Ash
Welcome to the warmest day of February and warmest day since mid-January. Sunshine gradually gave way to cloud cover and an approaching front tonight may trigger widely scattered rain showers, with the in short-term hi-resolution models on the southeastern corner of the state.
A bigger concern for the overnight and early morning commute Wednesday will be areas of locally dense fog. Snow melt today and temperatures cooling into the upper 20s/lower 30s provide the set up for a shallow layer of fog/stratus… and this will take some time to “burn off” tomorrow. So the brightest part of the day will be the afternoon, and temps creep back into the mid-40s.
For several days we’ve mentioned the possibility of strong/severe storms, unfortunately there’s no change to that thinking. We all really need to be weather aware Thursday. Dense fog will be a big problem to start the day.
Temps then surge into the upper 50s-lower 60s. A dynamic wind field teams up with a sharp cold front to bring an elevated risk of damaging wind to Central Indiana. Current timing appears to be late afternoon/evening and wind profiles/instability parameters suggest a low end tornado risk too… especially for the southern-third of the state.
Flooding may become the bigger story, with snow melt and heavy rain increasing the threat for all areas. It’s shaping up to be a busy day. Check back for further updates regarding timing, level of confidence, and greatest severe parameters.
This taste of spring warmth will be quite a tease, as there’s a high chance of unseasonably cold air returning next week… and possibly into March. We’re certainly earning our spring fever this year. Have a great evening.
Radar at 5pm shows a band of heavy snow/sleet that will move across Central Indiana and Indy metro… dropping a quick 1-2″ of snow and possibly some claps of thunder. This will be the back-breaker for roads this evening, that were already dicey in most locations. Be sate this evening
The transition back to snow is underway from west to east across Central Indiana… with a quick burst expected to drop a few inches around the Indy metro before this system departs. Road conditions will continue to go downhill from here, with numerous reports of slide-offs along and north of I-70.
With temperatures steadily dropping into the mid-20s, any untreated road or sidewalk will become a skating rink.
This precipitation is convective in nature, meaning rumbles of thunder are possible and heavy snow rates (1″ per hour) are still in play. Bottom-line expect slow to dangerous driving conditions the later we work into the evening.
Adding insult to injury will be areas of fog developing that will reduce visibility. Stay safe and more updates to come