test case from awt - 2011 domain: 2 a ugust runs

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Test Case from AWT - 2011 domain: 2 A ugust runs. Goal: trying to see why all the ensemble runs kill all the convection midway through the 6-h forecast cycle Real-time runs examined 12z EWP3 and STMAS_CI runs out to 6-h EWP3 run The “box of doom” with omega is shown - PowerPoint PPT Presentation

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Some LAPS/STMAS model comparisons for HWT cases

Test Case from AWT-2011 domain: 2 August runsGoal: trying to see why all the ensemble runs kill all the convection midway through the 6-h forecast cycleReal-time runs examined 12z EWP3 and STMAS_CI runs out to 6-hEWP3 runThe box of doom with omega is shownBut alone this would not explain the end of the reflectivity by ~3-h into the forecastThe temperature forecast shows warming through the entire atmosphere but highest near 500 mb.Increases with time but begins only 15-min into the forecastWould certainly be sufficient to cap the atmosphere For most of the atmosphere it looks like drying also occursSo warming and some drying appears to cap the atmosphere, but why does the warming occur? STMAS_CI runLooks reasonable, does a decent job with the echoes.Comparison of 500 mb temperatures at 12z on 2 August 2011

RUC analysis of 500 mb temperaturesThe analyses of 500 mb temperature are similar and compare well to the RUC analysis and observations.

EWP3 analysis

STMAS_CI analysisSTMAS_CI_CYC analysisComparison of 500 mb temperatures at 16z on 2 August 2011

RUC analysis of 500 mb temperaturesThe 4-h forecasts of 500 mb temperature from the STMAS runs are similar and compare well to the RUC analysis, while EWP3 is way too warm.

EWP3 4-h forecast

STMAS_CI 4-h forecastSTMAS_CI_CYC 4-h forecastCloser look at the EWP3 500 mb temperature forecasts from the 12z on 2 August run

EWP3 analysis of 500 mb temperaturesThe erroneous 500 mb temperature warming in the EWP3 run gradually moves across the domain.

EWP3 1-h forecast

EWP3 2-h forecastEWP3 4-h forecastEWP3 wind omega forecasts from the 12z on 2 August run

EWP3 analysis of omegaThe erroneous 500 mb omega in the EWP3 run appears to move in from the boundaries and emanate from convection over WI.

EWP3 1-h forecast

EWP3 2-h forecastEWP3 4-h forecast Closer look the omega forecasts- Cross-section location is shown below

EWP3 wind omega forecasts from the 12z on 2 August run 15 min interval output for first hour

EWP3 analysis of omegaThe erroneous omega seems to grow fairly gradually.

EWP3 15-min forecast

EWP3 30-min forecastEWP3 45-min forecastEWP3 wind omega forecasts from the 12z on 2 August run 1-h interval output for hours 1 to 4

EWP3 1-h forecastThere is a dramatic increase in vertical velocity (sinking largely in this cross-section) between hours 1 and 2, then the scale seems to break down into smaller horizontal scales but still large values (more waves if you will, sort of get this same interpretation from the horizontal omega plots at 500 mb shown earlier).

EWP3 2-h forecast

EWP3 3-h forecastEWP3 4-h forecastSTMAS wind omega forecasts from the 12z on 2 August run 1-h interval output for hours 0 to 3

AnalysisThe vertical velocity from the STMAS_CI run looks reasonable.

1-h forecast

2-h forecast3-h forecast

EWP3/STMAS_CI wind omega forecast comparison for hours 4 and 6 from the 12z forecast run

STMAS_CI 4-h forecastThere is a tendency perhaps for the erroneous vertical velocities in EWP3 to weaken by 6-h. The STMAS_CI run looks reasonable and is shown to compare to the EWP3 run.

STMAS_CI 6-h forecast

EWP3 4-h forecastEWP3 6-h forecast

EWP3/STMAS_CI sounding comparison for hours 0 to 6 from the 12z forecast run

analysisThe two runs are compared. The white arrows point to the STMAS_CI run (fatter arrow with wider head points to the temperature, the other white arrow to the dew point curve (dotted line, harder to see). The yellow arrows do the same for the EWP3 run.

The soundings are very close at the analysis time. By 1-h into the forecast the EWP3 run is considerably warmer, with the greatest warming at 500 mb, but really spread through pretty much the entire atmosphere. Note how the spread in temperature between the two runs grows with time. It appears that the EWP3 run (white arrows) is consistently more moist (at least at this point (grid point 25/25).

1-h forecast

4-h forecast6-h forecast

EWP3 sounding comparison for the first hour from the 12z forecast run

analysisIn this sequence we look at the sounding at point 25/25 from the EWP3 run only, at 15-min intervals for the first hour. The fatter yellow arrow points to the temperature profile and the thinner yellow arrow points to the dewpoint curve. The off-white vertical arrow is held at the 400 mb temperature from the analysis for reference. Using this point as a reference shows the gradual warming that begins at 15-min into the run.

15-min forecast

30-mon forecast45-min forecastEWP3/STMAS_CI cross-section temperature forecast comparison from the 12z forecast run

EWP3 analysisHere is another look at the temperature forecasts using the same cross-section as earlier. For reference the horizontal white line is at 500 mb, and the yellow line at 700 mb in each figure. You can see that the temperature at these two levels does not change much at all in the STMAS_CI run, but warms in the EWP3 run.

The initial temperatures (analysis) are close but not identical, particularly in the lowest 100-200 mb or so.

EWP3 4-h forecastEWP3 6-h forecastSTMAS_CI 6-h forecast

STMAS_CI analysis

EWP3AnalysisThe warming shown in the previous slides would explain why the echoes disappear in EWP3, eventually the domain is severely capped. STMAS looks good.1-h forecast2-h forecastSTMAS_CINOWRAD1200 UTC1300 UTC

1400 UTC

EWP33-h forecastThe echoes are pretty much gone by 3-h into the EWP3 forecast. General forecast from STMAS_CI looks good, misses the New England cells.4-h forecast6-h forecastSTMAS_CINOWRAD1500 UTC1600 UTC

1800 UTC