donsutherland1

Yes, that’s hail. For example, on August 11, 1989 and August 12, 1989, a trace was recorded. Temperature ranges on those days were 79-58 and 83-58 respectively. Both days had some thunderstorms. A temperature-based rule would flag those items for quality control. Unfortunately, the quality control algorithms don’t take into consideration such events. One can find them listed for numerous locations.

2.4” snow fell on May 2, 1897. There’s a chance that this storm could surpass that figure.

Wauseon (9 NW), OH: 4.0”

It appears that Indianapolis has reached 1.0” of snow. That would make today’s snowfall only the second on record where 1.0” or more snow fell on or after April 20th. The only other time that occurred was way back on May 2, 1897. This is also Indianapolis’ first measurable snowfall on or after April 20th since May 6, 1989.

As of 8 pm EDT, Indianapolis had picked up 0.9” of snow. That sets a daily record for April 20. Prior to 2021, no measurable snow had been recorded on April 20th.

As of 8 pm, light accumulations of snow have been reported around the greater Indianapolis area. It is all but certain that 2021 is the first case with measurable snowfall there on April 20th. 1.5” of snow had also been reported at Romulus, MI. Overall, it looks like Detroit remains in line for 2”-4” of snow, Indianapolis for 1”-2”, and Toledo with 3”-6”. However, it appears that snowfall amounts will be a little less than I first thought for Toronto (2”-4”/5 cm - 10 cm).

At 7 pm, snow was falling and accumulating in such cities as Indianapolis, where no measurable snow events had previously been recorded on April 20, Toledo and Detroit. Earlier in the day, Kansas City experienced its biggest snowfall on record after April 8, as 3.5" of snow accumulated. That storm will bring snow from the Great Lakes region into western and upstate New York State tonight into tomorrow. The snow will extend into parts of Ontario and Quebec, including Montreal and Quebec City. Snowfall estimates and daily records: Buffalo: 3"-6"; April 20: 5.5", 1901; April 21: 1.3", 1934 Detroit: 2"-4"; April 20: 1.2", 1947; April 21: 0.3", 1978 Indianapolis: 1"-2"; April 20: None; April 21: 0.7", 1901 Toledo: 3"-6"; April 20: 0.3", 2013; April 21: 2.0", 1922 Toronto: 2"-4" (5-10 cm); April 20: 0.9" (2.2 cm), 1978; April 21: 2.7" (6.9 cm), 1945 Windsor, ON: 2"-4" (5-10 cm); April 20: 0.9" (2.3 cm), 1947; April 21: 0.8" (2.0 cm), 1986 Farther east, the Middle Atlantic and southern New England regions will see readings rise into the 60s ahead of the strong cold front that will be pushed across the region as the storm far to the north and west of the region. A squall line with strong thunderstorms, damaging winds and possibly hail will mark the cold front's passage. Thursday morning and perhaps Friday morning could see the temperature fall below 40° in New York City. This could be the last time the temperature falls into the 30s in Central Park until next fall. The guidance is suggesting that the month could close with much above normal temperatures. Such an outcome would be consistent with the MJO's having moved through Phase 6 at a very high amplitude during the April 1-15 period. Since 1974, there were 7 cases where the MJO reached Phase 6 at an amplitude of 1.500 or above during April 5-15, as was the case this year. Only 1981 had an April 20-30 maximum temperature below 80° (75°). The average highest figure for such cases was 81.3°. The MJO's ongoing passage through Phase 7 at a very high amplitude is consistent with an outcome that typically yields 1-2 80° days. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -0.4°C for the week centered around April 14. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.33°C and the ENSO Region 3.4 anomaly has averaged -0.47°C. Neutral-cool ENSO conditions are now developing. Neutral ENSO conditions will likely be in place by the end of spring. The SOI was +21.41 today. The preliminary Arctic Oscillation (AO) figure was +0.172 today. On April 18 the MJO was in Phase 7 at an amplitude of 1.932 (RMM). The April 17-adjusted amplitude was 1.750 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 69% probability that New York City will have a warmer than normal April. April will likely finish with a mean temperature near 53.9° (0.9° above normal).

Kansas City picked up 3.2" of snow. That is its biggest daily snowfall and snowstorm so late in the season. The prior records are here: https://www.americanwx.com/bb/topic/54810-april-19-21-late-season-snow-potential/?do=findComment&comment=5986577

Yes.

As of 7 am CDT, Kansas City had picked up 2.6" of snow. Additional snow has fallen since that time. As a result, today's snowfall could wind up being the largest daily snowfall this late in the season and it could also be Kansas City's biggest snowstorm this late in the season. Existing records (April 10 or later): Daily Snowfall: 2.7", April 20, 1992 Biggest Snowstorm: 2.8", April 20-21, 1992 Prior to the 1992 snowstorm: Daily snowfall: 2.8", April 9, 1961 7.0", April 8, 1938 (occurred April 7-8, with a trace of snow on April 7 as rain changed to snow) Biggest snowstorms so late in the season: 4.0", April 8-9, 1983 7.0", April 7-8, 1938

For further perspective concerning Toledo, Toledo has seen 17 days on which 1" or more snow fell on or after April 10th. Once one moves to on or after April 20th, there were just 4 such days.

My thinking is 3"-6" (7.5 cm-15 cm). 4" (10 cm) looks reasonable.

Early storm reports coming in from Missouri show amounts of 2"-4" just north of Kansas City, including a high figure of 4.5". Late-season storms can sometimes overperform where the heavy banding takes place.

That is correct. Below is a list of Toledo's 1" or greater snowfalls on or after April 20: April 21, 1922: 2.0” May 8-9, 1923: 4.0” May 6-7, 1989: 1.3” April 23-24, 2005: 4.0”

At 7 am CDT, Kansas City was reporting heavy snow with a temperature of 33°. Kansas City remains on track for a 1"-3" snowfall. The daily record snowfall is 2.7", which was set in 1992.

My thoughts concerning the impending snow event and daily records for select locations: Buffalo: 3”-6”; April 20: 5.5”, 1901; April 21: 1.3”, 1934 Detroit: 2”-4”; April 20: 1.2”, 1947; April 21: 0.3”, 1978 Indianapolis: 1”-2”; April 20: None; April 21: 0.7”, 1901 Toledo: 3”-6”; April 20: 0.3”, 2013; April 21: 2.0”, 1922 Windsor: 2”-4” (5-10 cm); April 20: 0.9” (2.3 cm), 1947; April 21: 0.8” (2.0 cm), 1986

Morning thoughts... Today will be partly sunny and unseasonably warm. High temperatures will likely reach the lower to perhaps middle 70s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 73° Newark: 75° Philadelphia: 74° Tomorrow will be partly sunny and warm. As a strong cold front crosses the region, it could be marked by the passive of a squall line with severe thunderstorms. Farther west, the storm that will drag the cold front across the region tomorrow will bring a late-season snowfall to parts of the Great Lakes region into western and upstate New York late today into tomorrow. Snowfall estimates and daily records: Buffalo: 3”-6”; April 20: 5.5”, 1901; April 21: 1.3”, 1934 Detroit: 2”-4”; April 20: 1.2”, 1947; April 21: 0.3”, 1978 Indianapolis: 1”-2”; April 20: None; April 21: 0.7”, 1901 Toledo: 3”-6”; April 20: 0.3”, 2013; April 21: 2.0”, 1922 Windsor: 2”-4” (5-10 cm); April 20: 0.9” (2.3 cm), 1947; April 21: 0.8” (2.0 cm), 1986

Running through Bufkit, it's looking like both Detroit and Toledo could see more snow than what I described above if the subsequent guidance remains consistent. It will be interesting to see how things evolve overnight.

Tomorrow will be partly sunny and very warm. The temperature could surge above 70° in much of the region. A sharp cold front will likely cross the region on Wednesday, possibly with a squall line, bringing a short period of much below normal readings. Thursday morning and perhaps Friday morning could see the temperature fall below 40° in New York City. There is some chance that this could be the last temperature in the 30s for Central Park until next fall. Meanwhile, a storm will likely bring accumulating snow to parts of the Great Lakes region tomorrow into Wednesday. Detroit could see 1"-3" of snow while Toledo picks up 2"-4". Uncertainty about the actual accumulations is greater than normal given spring climatology and the large differences between the 12z GFS and the far more aggressive 12z HREF. The 18z GFS ticked northward relative to the 12z run with its forecast area of accumulating snow. The above amounts reflect a blend of the NBM, HREF, and ECMWF. Some of the guidance is again suggesting that the month could close with much above normal temperatures. Such an outcome would be consistent with the MJO's having moved through Phase 6 at a very high amplitude during the April 1-15 period. Since 1974, there were 7 cases where the MJO reached Phase 6 at an amplitude of 1.500 or above during April 5-15, as was the case this year. Only 1981 had an April 20-30 maximum temperature below 80° (75°). The average highest figure for such cases was 81.3°. The MJO's ongoing passage through Phase 7 at a very high amplitude is consistent with an outcome that typically yields 1-2 80° days. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -0.4°C for the week centered around April 14. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.33°C and the ENSO Region 3.4 anomaly has averaged -0.47°C. Neutral-cool ENSO conditions are now developing. Neutral ENSO conditions will likely be in place by the end of spring. The SOI was +12.83 today. The preliminary Arctic Oscillation (AO) figure was +0.021 today. On April 18 the MJO was in Phase 7 at an amplitude of 1.932 (RMM). The April 17-adjusted amplitude was 1.750 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 64% probability that New York City will have a warmer than normal April. April will likely finish with a mean temperature near 53.8° (0.8° above normal).

Unfortunately, not. The lack of such measurements leaves gaps in the climate record.

MPO no longer records the daily snowfall. There is also no local storm report for that event.

Mount Pocono picked up 8.2”. I have no data from Lake Harmony.

Probably not. JFK should reach the mid-60s. NYC will probably top out at 66-67. Clouds will increase this afternoon.

Central New York State received some snow from the follow-up system, but it passed to our north and west.

Today is one day where the high temperature will likely beat the guidance. The MOS shows 65 as a high for Central Park. At 11 am, it was already 63 there.