Debunked: Frequency Pulse Causes Snow in Wisconsin

[scombrid]

http://sincedutch.wordpress.com/2012...circle-sweeps/

Perhaps this should go in Pseudoscience but since Dutch made his name with youtube vids I'll place it here for now:

He claims that a "frequency pulse" on 25 November caused snow that NWS did not predict on 27 November. He said that the forecast was for clear weather.

His prediction was:

Two days ago — November 25, 2012 at approximately 107 UTC .. a high frequency pulse from the NEXRAD RADAR appeared out of Lacrosse Wisconsin.
I put this watch/alert out on Facebook — watch the area for up to 72 hours for weather to develop , usually severe or odd weather conditions follow these RADAR pulse events


However, even in the screen shot that he provides of the forecast there is a forecast for a 20% chance of snow associated with the approaching front so that contradicts his claim that the forecast was for all clear. The forecast discussions for 24 November (which predates Dutch's "flash" forcast) mention that light snow may accompany a passing front:

Here are area forecast discussions from mid day on the 24th.

000
FXUS63 KARX 242100
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
300 PM CST SAT NOV 24 2012



ANOTHER SFC-700MB FRONT/TROUGH APPROACHES ON TUE
WITH AN INCREASE OF MOISTURE/CLOUDS ABOVE 500MB. THIS ONE LOOKS
TO HAVE WEAKER FORCING/LIFT AND LESS MOISTURE THAN THE ONE PASSING
TONIGHT...AND LEFT TUE/TUE NIGHT DRY.

AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1204 PM CST SAT NOV 24 2012


THIS WEAK CLIPPER LOW DROPS SEWD INTO S-CNTRL ONTARIO ON
TUE WITH A CDFNT EXTENDED SWWD THRU CNTRL MN. LOOK FOR CLOUDS TO
START INCREASING OVER THE FCST AREA TUE AFTERNOON AS MODEST Q-G
FORCING DEVELOPS IN ADVANCE OF THE FNT. A W-SW WIND SHOULD ALLOW
FOR TEMPS TO WARM A FEW DEGS OVER MON`S CHILLY VALUES WITH MAX
TEMPS TYPICALLY IN THE UPR 20S TO LWR 30S.

THE CDFNT SWEEPS ACROSS WI TUE NGT...BUT WITH THE BETTER FORCING
PROGGED TO PASS TO OUR NORTH (ASSOCIATED WITH A SE MOVING
SHORTWAVE)...IT APPEARS THAT SNOW AMOUNTS ACROSS NE WI WL BE
LIMITED

So NWS was forecasting a front to pass mostly dry with moisture aloft with the frontal passage and snow only reaching the ground in limited amounts to the north and east of La Cross and likely not at all in La Cross. And that was the NWS forecast on the 24th.

That weather is exactly what is depicted in the radar screen shots he provides. It never snowed in La Cross and the snow to the north was very light, mostly not reaching the groud because the airmass was so dry below the 500mb level. The weather on the 27th was neither strange or odd in that region. The weather was associated with a short wave passing to the north and dragging through a dry front. Most of the weather associated with the front occurred far away from the supposed "frequency pulse" nearer to the passing shortwave. Such weather is common in that area this time of year.

As for the "frequency pulse". It is of the same origin as is delt with in another thread. It is incorrect data fed into the mosaic creating a display error.

http://metabunk.org/threads/937-Debu...hsinse-version)

[scombrid]

This is the level III base reflectivity image at 10pm UTC on the 27th which is the time that Dutch claims that weather that was not forecasted was occurring. Notice that the returns are all distant from the radar. They are aloft and not reaching the ground. Plus the most intense returns are in the 15-20 dBZ range. That is extremely light. Quite likely you can see the sun through it (you know the type of winter day where the sun shine dull through diffuse mid-high clouds). That is consistent with what NWS was predicting to occur with passage of the front 3 days prior.

[scombrid]

This is Dutchsinse's screen capture supposedly verifying his "forecast". It depicts very light precipitation. He made no attempt to verify whether it was reaching the ground. It also incorrectly states that the forecast for the 27th was for a clear day. The forecast as illustrated in the forecast discussions already provided was for very light precipitation, likely not even reaching the ground and that is exactly what is illustrate in this screen capture. Also notice that the vast majority of the precipitation is nowhere near the supposed "pulse" that he depicts in his blog post.