Status:Ongoing analysis Material from: Ervin, Linus
Discussed in the following Daily reports:
http://intra.ecmwf.int/daily/d/dreport/2016/01/19/sc/
http://intra.ecmwf.int/daily/d/dreport/2016/01/20/sc/
http://intra.ecmwf.int/daily/d/dreport/2016/01/21/sc/
http://intra.ecmwf.int/daily/d/dreport/2016/01/22/sc/
Picture
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
3. Predictability
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.
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.
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