Synoptic situation

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The 1953 North Sea Gale in Perspective of
Historical NWP efforts. H. M. van
den Dool, R.E. Kistler and S. Saha, at NCEP

• ? Synoptic situation
• ? Modern Forecasts of 1953 storm(ReForecasting)
• ? Expand in three ways
• a) Barotropic Forecasts
• b) Initial error hand vs present analysis (53
  data)
• c) (nearly) Contemporary UK NWP for 53 case
• Acknowledge Anders Persson about point c.

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Mean Sea Level Pressure Maps for Jan 29 Feb 1,
1953, every 3 hours from NCEP-NCAR Reanalysis
(Kalnay et al 1996 Kistler 2001
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29/0
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30/0
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31/0
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01/0
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From Hay, R. F. M., and J. Laing, 1954 The storm
of 31st January - 1st February 1953. Mar. Obs.,
24, 87-91.
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Height fields Jan 28 - Feb 1, 1953 every 6 hours
(Reanalysis)
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• To be sure This disaster was not just
  meteorology1) Oceanography, wind stress effect,
  Kelvin waves and astronomical tides, wind
  waves2) Coastal defense, and its
  maintenance3) Preparedness, warning system,
  protocol, bureaucracy, communications,
  evacuation4) Assessing the risk of a given surge
  forecast

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Forecasts valid for Feb, 1, 1953, 3Z

• Reanalysis model T62L28

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The previous map is a contemporaneous hand
analysis, digitized at 2.5 by 2.5 grid. The
original looks like this
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Source KNMI, F. H. Schmidt- editor,1960
Meteorologische en Oceanografische aspecten van
stormvloeden op de Nederlandse kust. Bijdrage tot
het rapport van de Deltacommissie door het KNMI.
Staatsdrukkerij- en Uitgeverijbedrijf - s
Gravenhage. pp200.
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• ? Synoptic situation
• ? Modern Forecasts of 1953 storm
  (ReForecasting) by NCEP(several resolutions
  ETA), ECMWF(several resolutions), Hirlam
• ? Expand in three ways for Historical NWP
  aspects
• a) Barotropic Forecasts
• b) Initial error hand-analysis vs Re-analysis
  (53 data)
• c) (nearly) contemporary UK NWP of 53 case

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dAVA (global barotropic) forecasts

• M/Mt (?-?2?) - Vn .L? - V.L (?n f ?)
  - DL4 ?- K ?,
• where Vn and ?n refer to climatological mean
  flow, and ? is anomaly vorticity.
• T30L1
• Cressman-Bolin correction applied to anomaly.
  Parameter ?2 found thru adjoint study (Rinne et
  al 1993)
• 1980s type barotropic model

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Verification by numbers (Anomaly Correlation 500
mb height)
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On the initial error

• handanalysis minus Re-analysis is 2mb/25gpm
  for MSLP/Z500 respectively. Atl-Eu domain for
  1953 data.
• CDAS/Reanalysis (T62L28) has currently (Jan)
• 1.5mb/12.0gpm (0hr, fit to radiosondes)
• 1.8mb/18.1gpm (6hr, guess to obs) (EuroAtl)
• It is (?) amazing that the initial error for
  1953 Reanl, with so much less data than in 2004,
  is not even a factor of 2 larger.

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QJ 1958



INITIAL 30 jan 15Z
24 hr barotropic forecasts
31 jan 15Z (anl)
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Analysis 31 Jan 15Z 1953, 500mb(ft)
24 hr forecast of 500mb height by
Sawyer_Bushby Model, verifying Jan 31 15Z, Met
Magazine 1954
24 hr by Sawyer_Bushby model
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If the Sawyer-Bushby forecast had been
right, the calamity would have been a lot more
calamitous than it already was. Free
after Discussion(1954) and Hinds(1981).
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Water Level Forecast 12 Hours
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• Conclusions
• With current NWP models and analyses, but 1953
  data, forecasts out to 2 (4) days appear
  possible.
• ? KNMI(1960) conclusion about lack of data (easy
  scapegoat) is clearly overstated (for this case).
  
• Accurate barotropic forecast are possible out to
  30 hrs (i.e. after the bomb had developed)
• Differences between hand analysis and Reanalysis
  are 2mb and 25gpm (1953 data coverage). Jan2003
  CDAS errors are 1.6mb/15gpm.
• There are a few early NWP efforts with regard to
  the storm of 1953. Jan 30/31 15Z was one of the
  canned cases used at UKMO. Bushby-Sawyer 24hr
  forecast was remarkable!

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A KNMI initiated warning system, implemented in
1916 (following a previous flood)Three
options1) Say nothing (benign circumstances)2)
Warn for significantly enhanced water levels for
the next two astronomical high tides (by
region)3) Warn for dangerously enhanced water
levels for the next one astronomical high
tide.? Saturday Jan 31 at 10am option 2
warning was issued? Saturday Jan 31 1715 (they
had to wait until after the afternoon high tide,
in order to avoid confusion) option 3 (for the
first time in history) (Warnings were issued to
other authorities (supposedly they knew what to
do), and to the public via radio at 1800 onward.
Note there was no radio after midnight. Zero
communication during the disaster.)
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RMS-errors of MRF(GFS) forecasts, and initial
errors.

• 
  Z500
• Lead gt 0 24 48 72 96 hr climo
  -------------------------
  ------------------------------------------
  30 Jan 3Z
  0(28) 24 43 57 96 140 31 Jan 3Z
  0(27) 34 54 68 95 129 01 Feb 3Z
  0(22) 24 57 73 108 137 gpm MSLP Lead
  gt 0 24 48 72 96 hr climo
  --------------------------------------------------
  ----------- 30 Jan 3Z 0(1.8) 3.2 5.2 7.4
  9.6 10.731 Jan 3Z 0(2.0) 4.1 6.7 8.1 7.4 12.
  8
• 01 Feb 3Z
  0(2.4) 2.9 6.3 6.7 9.8 15.1 mbar