Status:Finalised Material from: Ervin, Linus, Tim, Fernando
Discussed in the following Daily reports:
1. Impact
On 22-24 January a severe blizzard hit the U.S east-coast and broke records in accumulated snowfall in several places. The amount was only mm from the record in Central Park (NYC) and broke the record on JFK. For Washington DC (Dulles) it ranks as the 2nd worst snowstorm. After the cyclone New Jersey was hit by coastal flooding.
2. Description of the event
A nice summary of the meteorological conditions during the storm can be found here: https://www.washingtonpost.com/news/capital-weather-gang/wp/2016/01/25/the-12-best-meteorological-images-of-the-blizzard-of-2016/
The plots below show the 24-hour accumulated precipitation for 22 Jan 12z-23 Jan 12z (left) and 23 Jan 12z - 24 Jan 12z. Note the local differences around Washington DC and NYC.
Next plot is a preliminary plot, from the US, for the greater NYC area, showing post event snow depths in inches. For reference Long Island, east of the city, is the island in the lower right.
3. Predictability
3.1 Data assimilation
3.2 HRES
The plots below show HRES forecasts of accumulated precipitation 23 Jan 00z - 24 Jan 00z (shade) and MSLP on 23 Jan 12z. The observed precipitation is in the first panel.
The plots below show the snow cover in the analysis (first plot) 24 Jan 06z and forecasts valid at the same time.
3.3 ENS
The plots below show the accumulation precipitation 22 Jan 12z-24 Jan 12z (48h) for ENS o-suite (blue) and HRES o-suite (red). The left plot is for Washington DC (obs 27-57 mm) and the right for New York City (obs 17-47 mm).
The plots below show the EFI and SOT for 72-hour precipitation 22-25 Jan all all 00z forecasts.
3.4 Monthly forecasts
3.5 Comparison with other centres
4. Experience from general performance/other cases
201401 - Snowstorm - North-eastern U.S.
201402 - Snowstorm - US east-coast
201501 - Snowfall - US east coast
5. Good and bad aspects of the forecasts for the event
- Early signal (from Sunday 17 Jan 00z) and very consistent forecasts
- Too low accumulation over NYC
- Question about snow density for the case
1 Comment
Erik Andersson
Thanks for the detailed reporting on this important severe weather case for our forecast users. I can forsee that we will becoming back to this case in future, and also that we will be reporting on our performance for this case to our committees and Council.
Would be good to include some feedback from US forecasters on the ECMWF forecast guidance, if/when available.