Status:Ongoing analysis Material from: Ervin, Linus, Mohamed
Discussed in the following Daily reports:
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The below below shows our NEXRAD verification product with the last HRES forecsast forecast included (27 Jan 00z).
3. Predictability
3.1 Data assimilation
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Observation statistics for 26 Jan 00z for radiosonde mid-troposphere temperatures are shown in the plot below. To stations (72215 and 72230) show large positive observation departures (model too cold), both in respect to first guess and analysis. At this time, the trough was located above the two stations.
The plots below show the time-series of the two stations. Both stations show similar departures on 26 January, although the magnitude of the departures are not extreme.
3.2 HRES
The plots below show the 24-hour precipitation from HRES valid 27 January. Before 24 January it was little trace of the system, although there was precipitation further out on the Atlantic. All forecast but the last had too much precipitation over New York city (marked with an hourglass symbol).
Gallery includeLabel hres_tp sort comment title HRES 24-hour total precip. 27 Jan
3.3 ENS
The two series of plot below show the cyclone feature plots for valid 27 Jan 12z. The spread decreased significantly around 24 January.
Gallery includeLabel dal_sf sort comment title Cyclone feature plots for 27 Jan 12z max snowfall
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The plot below shows the CDF for 24-hour snowfall for NYC for 27 January. The last (27 Jan 00z, red) and second last (26 Jan 12z, purple) differs considerably.
The plot below shows the CDF for 24-hour snowfall for Boston for 27 January. Here the last forecasts are much more consistent.
The plots below show the position of the cyclone in each ensemble member at 27 Jan 12z (symbols). The line starts 12 hours before and ends 12 hours later. Grey lines are for ensemble members, green for HRES (currently missing in the right plot), and analysis (red). The plots are from 27 Jan 00z (left), 26 Jan 12z (middle) and 26 Jan 00z (right). The westward shift is apparent in the two earlier forecasts.
3.4 Monthly forecasts
The plots below show monthly forecasts for 2-metre temperature anomalies valid for the week 26 Jan - 2 Feb.
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