Local CWF Formatter Changes

1
Local CWF Formatter Changes

• Matt Moreland
• NWSFO HGX
• April 2004

2
Common Forecaster Concerns

• Wave height ranges do not match what you have in
  the grids
• Wave heights are worded consistently too high
• Wind speeds come out too high ? with 11 grids of
  16 knots and 1 grid of 20 knots, formatter would
  output winds AROUND 20 KNOTS
• Chop phrasing for inland waters areas does not
  match the associated wind speeds

3
Factors Affecting Marine Fcst (1)

• Marine forecaster edits all the winds (inland and
  offshore) ? inland winds usually less than 15 mph
  in our CWA
• Model surface winds (SmartInit) not ideal yet ?
  GFS usually too high and Eta can be too low in
  post-frontal situations
• Wave heights GWW model doesnt work that well
  for us ? usually edited by hand

4
Factors Affecting Marine Fcst (2)

• Water temps can see a 25 degree or higher range
  in SSTs in mid-winter
• Land breeze/seabreeze interactions
• Run GFE in 2.5 km resolution to better contour
  the coastal effects
• Lots of verification in CWA 2 official buoys,
  PORTS data, TABS data (Texas Automated Buoy
  System)

5
Factors Affecting Marine Fcst (3)

• Editing methods vary among forecasters some
  insist on blocky edits for WaveHeights, others
  stick with preferred contouring
• SmartTools used to create WaveHeight grids based
  on surface winds ? a good first guess
• HGX issues a Tide Forecast (TIDHGX) ? uses TCOONs
  data and other sites for tide level verification

6
Our Current CWF (1)

• Use WaveHeight grids solely to produce Seas (no
  explicit gridded display of swell)
• Have two edit areas (two bays) used in _BayAreas
  and _ChopAreas
• No edit areas included in BayAreasWaves,
  BayChopAreas, IntracoastalChopAreas, or
  LakeChopAreas

7
Our Current CWF (2)

• May include single wind values with wind speeds
  up to 20 knots, and 5 knot wind ranges with
  speeds up to 25 knots
• Derive marine headlines from the Headline grids
• Changes detailed here have greatly improved wind
  speed, wave height, and inland waters chop
  wordings

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Two Possible Wave Height Fixes(suggested by
Edward Tirado)

• Change WaveHeight sampling method
  frommoderatedMax to moderatedMinMax
• ? use a 6 hour sampling period
• -- OR
• Add WaveHeight to moderated_dict method to weed
  out the highest values

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moderated_dict Method
def moderated_dict (self, parmHisto, timeRange,
componentName) dictWind (0,
20) dictWaveHeight (0, 20) return
dict This method will weed out highest 20 of
Wind and WaveHeight values when data sampling
takes place.
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Sampling with moderatedMinMax

• Found this change to be the most effective (even
  better than using moderated_dict)
• Works best when you add significantly more detail
  to the table in the wave_range method

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wave_range Method
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Changes to wave_words

• In the wave_words method, use different values
  for determining the average (avg)
• min, max self.getValue(wave, MinMax)
• avg self.getValue(wave, Average) new line
  added
• avg (min avg) / 2 changed from (min
  max) / 2
• Basically an average of the minimum and average
  WaveHeight values, rather than the average of the
  minimum and maximum values
• Results in a slightly lower value being passed to
  the table in the wave_range method ? the
  formatter then outputs lower wave height values

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Wind Speed Fixes (1)

• Sample wind speed twice in the vector_mag_hook
  method
• maxWind, dir tree.stats.get(Wind, timeRange,
  mergeMethodMax)
• avgWind, dir tree.stats.get(Wind,
  timeRange, mergeMethodAvg)
• maxWind (maxWind avgWind) / 2
• Results in a slightly lower maxWind value used to
  develop phrasing in vector_mag_hook
• This is a band-aid approach ? however after
  testing several different sampling combinations,
  this one worked very well

14
Wind Speed Fixes (2)

• Changed value in marineRounding method from 5
  to 1 ? resulted in much more accurate wind
  speeds
• def marineRounding(self, value, mode,
  increment, mixFlag)
• mode Nearest
• .
• return self.round(value, mode, 1)
• Issue at low wind speeds this change will
  sometimes result in an off phrase (like 6 TO 11
  KNOTS or 7 TO 12 KNOTS) ? must correct these
  phrases in the _postProcessProduct method

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Wind Speed Fixes (3)

• Include wind speed in moderated_dict method to
  eliminate the highest values
• def moderated_dict(self, parmHisto, timeRange,
  componentName)
• dictWind (0, 20)
• return dict

16
Inland Waters Phrase Changes

• Added in chop_phrase method
• Use BASE version of chop_setUp instead of the
  Southern Region CWF_Local one ? this version was
  not working for us
• Amend chop_words method to get the phrasing we
  want

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chop_setUp method
Set inlandWaters self._chopAreas(tree, node)
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chop_words method (1)

• Sample wind speeds twice in this method (similar
  to what we did in vector_mag_hook method for
  wind)
• Takes an average of the maximum wind and average
  wind, rather than just using the max wind to
  determine your chop phrase
• def chop_words(self, tree, node)
• statDict node.getStatDict()
• stats self.getStats(statDict, Wind)
• ..
• timeRange node.parent.getTimeRange()
• maxWind, dir tree.stats.get(Wind,
  timeRange,
• mergeMethod Max)
• avgWind, dir tree.stats.get(Wind,
  timeRange,
• mergeMethod Avg)
• maxWind (maxWind avgWind) / 2

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chop_words method (2)
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chop_words method (3)