We typically receive the radar 'digital precipitation arrays' (DPAs) from
each radar site every 6-10 minutes.  For each radar site, we use the DPA 
that is closest to the top of the hour and within a +/- 10 minutes window
for that hour's analysis.  DPAs outside of the +/- 10 minutes window
(e.g. 1750-1810Z, for the 18Z analysis) are not used.  Occasionally there
is a data transmission problem that leads to a gap in the radar data. 
If there are no DPA reports covering the +/- 10 minutes window at the 
top of an hour, then radar-related analyses (i.e. all except the 'gauge-only'
analysis) are not made for that hour.  

Data transmission outages tend to happen when the weather is quite
active over ConUS, because that's when the transmission lines tend to
have traffic that exceeds their capacity. 

When there is a missing hourly analysis, the 6h/24h analyses that contains 
that hour are also considered missing.

Hour ending   Problem                 Cause
  (UTC)
-------------------------------------------------------------
20081101-
  20081103:   The following files are missing: 
                 6-hourly accumulations ending 2008110118
                 All 20081102 files
                 6-hourly accumulations ending 2008110300
                 24-hour accumulations ending 2008110312
              Cause of this outage: around 13Z 31 Oct, we began receiving from 
              CBRFC what appeared to be forecasts 2 or 3 days into the future: 
              for example, in 31 Oct, there are files with GRIB header that 
              indicate that they are valid at 60-66 hours (with a reference 
              time of 12Z 31 Oct).   This has caused some problems in our 
              mosaic processing since it was set up to handle 'past' (analysis)
              files, not files with future time stamps.  Turned out CBRFC began
              migrating to a different machine and somehow the forecast files 
              got into the analysis stream sent to us.  On 4 Nov CBRFC 
              discontinued these rogue sends and things went back to normal.  

2008011601:   No DPA received between 00:22-01:35Z.  
20071119:     Dataflow from TOC disrupted (per SDM log).  Gauge and radar 
              data not available for 11-12Z.  No analysis.  
2007101505:   No DPA received between 04:30-05:23Z.
2007080422:   No DPA received between 21:47-22:40Z.
2006072513:   No DPA received between 12:31-13:37Z.
20060502:     No DPA report during 08:44-10:10Z.  No METAR gauge data for 
              09-14Z.  HADS gauge data appear to be missing/short 08-16Z.
 
2006021516:   Only 1 DPA report (from KGSP in South Carolina) was received 
              between 15:15-16:15Z.

2005101319:   Very scant coverage due to lack of DPA.  Likely related to 
              general outage of IBM White 1400L to 1820L.

2004121317:   There are no radar-related analysis for 17Z and 18Z.  No 
              DPA received from 16:41-17:45Z.

20040920-21:  There are no Stage II analysis for 10-11Z and
              17-23Z 20 Sept, and 00Z 21 Sept.   

              No radar data received between 09:32-11:25Z, No METAR gauge
              data for 11-12Z, and 16-23Z.  In the process of coping with
              the wide-spread data outage, the the hourly precipitation 
              analysis script was modified to eliminate the 'mid' run, which
              unfortunately led to a mismatch between the number of POE 
              jobs to be run and the number of total tasks in the SMS script, 
              causing the Stage II jobs to fail.  This problem was fixed on 
              20Z 21 Sept.  Re-run went back to 01Z 21 Sept.  


2004061002:   No radar data received between 01:45-02:02Z.  


20040509:     No radar data received between 05:50-07:13Z.  No gauge data
              05-08Z.  So no gauge-only analysis for 05-08Z.  No radar-related
              analysis for 06-07Z.  

2004043018/2004050112: 6-hourly gauge-only accumulation ending 2004043018 
              and 24-hour gauge-only accumulation ending 2004050112 were
              missing.  Hourly analyses during 2004043013-2004043018 were
              too sparse, causing the 6-hour totals ending 2004043018 to be
              all missing.

2003122614:   No radar data received between 13:21-14:19Z.
2003091020:   Received only 3 radar reports between 19:50-20:10Z.  

2003082704-2003082808:   
              Sparse hourly coverage 04-07Z; no data 08Z.
              Reason: power outage during the evening of Tue 26 Aug.  Even
              after the computers recovered, the outage-related backlogs
              caused disruption in incoming dataflow.  

2003072201    No radar data received during 0047-0120Z
2003071205-2003071210,
2003071223-2003071322: 
              Major network disruption of over 13 hours during the first 
              half (UTC, approx.) of Saturday 12 Jul.  No radar data 
              during 04:08Z-10:27Z.  In the process of rescuing as many of 
              the operational jobs as possible, the hourly precipitation 
              analysis script was modified on 23Z 12 Jul, which 
              unfortunately led to a mismatch between the number of POE 
              jobs to be run and the number of total tasks in the SMS script, 
              causing the Stage II jobs to fail.  This problem was fixed on 
              17Z 14 Jul.  Re-run went back to 23Z 13 Jul.  

2003061400    No radar data received during 2335-0015Z.  

2003010117    Only one radar report received during 1650-1710Z
2003010114    No radar data received during 1322-1410Z

20021213      No radar data received during 0542-0616Z,
                                            1343-1428Z,
                                            2245-2315Z,
              hence no radar-related analyses for 06Z, 14Z and 23Z.

              16Z radar-related analyses are sparse due to many unavailable
              radar reports during 1550-1610Z.

20020505      daily tar file corrupted, some compressed files
              cannot be decompressed.

2002032719    No analysis made        OSO data outage.  No radar
                                      data received during 1840-1926Z
                                      (1850-1910 data needed to make
                                      19Z analyses)

2002010103    Spotty radar coverage   Majority of radar reports were not
                                      received at NCEP for that hour

2001083118    No analysis made        OSO data outage.  No radar
                                      data received during 1735-1843Z
                                      (1750-1810 data needed to make
                                      18Z analyses)