I was taking a look through some historical analogs of situations similar to the possible February 14-18 snow event, and came across an interesting fact: Set-ups with similar situations historically have favored snowfall in the Midwest and Ohio Valley regions.
This will be a description on the 'most favorable' historical analogue that fits into this storm.
During the analogue date (February 13, 2009), here were the teleconnections compared to forecasts for this storm:
ENSO: -0.7
Comparison: Fair
PNA: -0.5
Comparison: Too Much Model Instability to Determine Comparison
NAO: -0.4
Comparison: Fair
AO: -2.5
Comparison: Bad
Teleconnections are not that good in comparisons at this time, so this may not end up comparing to this analogue the best. But let's keep looking.
The thing I am seeing is that the general NAO forecast and analogue comparison should be at least 'fair'. This level of comparison ought to be sufficient enough to not impact the storm too much. A much different AO may make a difference, but likely just in the amount of cold air. The PNA may end up as the big player.
500mb analysis indicates that the analogue storm emerged from northern New Mexico. The forecast storm is looking to emerge from the same area. By 'same', I mean right on the New Mexico/Colorado border, just like the analogue storm.
There are some differences in relative humidities and jet stream strengths between the GFS forecast and the analogue storm. The jet stream looks like it will be weaker than what the analogue storm has in play. The relative humidity (RH) differences look to be wetter in the forecast storm, meaning some additional precipitation could be in play.
And here's what we've all been waiting for: The snowfall analogue map.
Snowfall is favored for this storm in Nebraska and Iowa.
Again, the teleconnections are not all figured out and may play a different role in this storm that is forecasted. Also, storms do not 'play by the rules' by any means, so this might not even matter in the storm's final result.
Any questions can be asked below.
-Andrew
This will be a description on the 'most favorable' historical analogue that fits into this storm.
During the analogue date (February 13, 2009), here were the teleconnections compared to forecasts for this storm:
ENSO: -0.7
Comparison: Fair
PNA: -0.5
Comparison: Too Much Model Instability to Determine Comparison
NAO: -0.4
Comparison: Fair
AO: -2.5
Comparison: Bad
Teleconnections are not that good in comparisons at this time, so this may not end up comparing to this analogue the best. But let's keep looking.
The thing I am seeing is that the general NAO forecast and analogue comparison should be at least 'fair'. This level of comparison ought to be sufficient enough to not impact the storm too much. A much different AO may make a difference, but likely just in the amount of cold air. The PNA may end up as the big player.
500mb analysis indicates that the analogue storm emerged from northern New Mexico. The forecast storm is looking to emerge from the same area. By 'same', I mean right on the New Mexico/Colorado border, just like the analogue storm.
There are some differences in relative humidities and jet stream strengths between the GFS forecast and the analogue storm. The jet stream looks like it will be weaker than what the analogue storm has in play. The relative humidity (RH) differences look to be wetter in the forecast storm, meaning some additional precipitation could be in play.
And here's what we've all been waiting for: The snowfall analogue map.
 |
| 72-hour snowfall ending February 14, 2009 |
Again, the teleconnections are not all figured out and may play a different role in this storm that is forecasted. Also, storms do not 'play by the rules' by any means, so this might not even matter in the storm's final result.
Any questions can be asked below.
-Andrew
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