I WILL HAVE MORE GRAPHICS WITH THIS POST SOON…………
A serial derecho with origins in Nebraska & South Dakota produced widespread wind damage & tornadoes from those locations all the way to Pennsylvania.
In our viewing area widespread wind damage occurred during the very early morning hours of April 21. The greatest concentrations of straight-line winds damage were reported from Tippecanoe, Cass, Montgomery, Fulton & Miami counties. If there were tornadoes here, they were brief EF0s or low-end EF1s, as there no evidence of any substantial ones, but some of the damage points to brief rain-wrapped, “weaker” ones.
Roofs & chimneys were damaged, trees & electric poles were snapped, fences destroyed & barns blown down. Also, cellars were reported flooded as tail end of apparent of derecho was paralell to southwest flow aloft & training occurred. The Purdue University station measured 1.47″ of rainfall.
Strong low-level jet is evident after one of the hottest April days on record in our area on April 20. Low-level winds were very strong out of the south around Bermuda-type high. To this point,1896 was the warmest April on record in our area (since 1868).
In fact, highs reached the upper 90s in the Carolinas & lower to mid 90s in the Mid-Atlantic April 20 & 21 with impressive upper ridging in southeastern U.S.
It is likely that this ridge also caused trained of tail-end of that derecho, which led to some of that flash flooding.
Tornadoes of note from this outbreak were at Fremont, Ohio (suburb of Cleveland) when a violent F4 struck. HOWEVER, it appears this occurred ahead of the main line with a supercell. Even with strong southwest flow, one would wonder if the lake breeze was an influence or a wind shift from south to southwest well south of the warm front.
The serial derecho struck Indiana & during the morning of April 21 & this supercell & tornado occurred on April 20 at 3 p.m.
Even in image below of a serial derecho from 2011, notice discrete activity in northern Ohio ahead of the main event.
Today was nice & warm with the warmest day so far this year in our northern counties!
It is still warm tonight & damp with a true feeling of spring! It even smells like spring (fresh, damp soil).
We received just a trace of rainfall at WLFI, but our northwestern areas have received anywhere from 0.10 to 0.40″ of rainfall. Our southern counties received a trace to 0.06″. Our Rensselaer station measured 0.26″ & the Jasper County Airport recorded 0.20″ as of 9:54 p.m.
Scattered showers/t’showers will exit tonight. Rainfall will not be impressive at 0.10″ to perhaps as high as 0.30″.
This will be followed by a windy Tuesday with highs at 57-65. North winds may gust to 35 mph with scattered fair weather cumulus clouds. The clouds will be more numerous in our northeastern counties.
Frost/light freezing is likely tomorrow night with lows of 30-33, followed by a mostly sunny & less windy Wednesday. Highs will run 58-65 with increasing high clouds late in the day as a warm front approaches.
Supercells are likely Minnesota to Texas Wednesday with wind, tornadoes & large hail.
Thursday-Next Wednesday (Which Is April 30)………..
With highs in the 70s, southwest winds may gust to 35 mph Thursday.
A line of showers/storms likely here Thursday evening with potential of some scattered severe straight-line wind gusts here.
Over the weekend, with our cooler weather, upper low spinning in the Southwest will bring multiple rounds of severe t’storms with wind, hail & tornadoes from Texas to Kansas & Louisiana to perhaps as far north as southern Missouri.
This severe weather threat may extend into the Deep South on next Monday-Tuesday, while rain may get as far north as Indianapolis.
However, we look dry………………….for now……………….with highs in the 50s to around 60 (with partly cloudy skies). Strong Canadian surface high to our north should protect us from rain, but it will be rather cool.
This is a tight-rope on how far north this rain will get & a close call, stay tuned.
THIS WILL BE THE BEGINNING OF DOMINANT NORTHWEST FLOW APRIL 26-MAY 7.
In terms of frost/light freeze…………Saturday night look to drop to 30-33 & Sunday night, 31-36.
Upper trough will bring cold pocket aloft through around May 2-3. This will tend to bring some scattered instabilityshowers/t’showers with perhaps some graupal. Highs May 1-4 will run 56-64 with lows in the 30s & 40s, it appears. Looks like we may even have some patchy frost during this time, especially on the night of May 4. I think Newton, Jasper, Pulaski, Fulton, Cass & Miami counties could drop to 31 or 32. Surface high looks to be right overhead. The rainfall does not look heavy or significant.
A brief return to 65-70, then seems likely May 6 (61-66 May 5). In terms of rainfall, there is a shortwave & cool front that may pass May 6, but rainfall with it looks insignificant with 59-65 May 7.
A surge of warmth seems likely after the May 9 time frame with 80s.
OVERALL, PATTERN LOOKS RELATIVELY DRY & COOLER-THAN-NORMAL AS WE MOVE INTO EARLY MAY.