Tuesday, February 21, 2012

2/19 storm recap

Here's a review of how our forecast for Sunday's snowstorm panned out..

Above is the final call map from Saturday afternoon before the storm..it was pretty similar to the first guess map...with the biggest change being expanding the heavier snows a bit farther south and east.  After I issued this map was about the time when the short range models started collapsing towards the idea that the storm would stay farther to the south, and a not have nearly as expansive precipitation field than what earlier models had been predicting.  I knew once these rather reliable short range models started agreeing on this that the final call map was going to have some issues, particularly for northern areas.  I also knew that totals in central and SE VA would end up being the lower numbers of the predictions I made.  I still thought that the precipitation field would get a bit farther north than what models were indicating by just looking at the radar and noticing that the models weren't doing the best job even initializing correctly.  With that said, we hung our hats on this forecast, not only because of the reason I just mentioned, but also because I am not a fan of issuing a post-final call map 12 hours before an event.  What's the point of that?  Anyways, yes the precipitation field got farther north than what the models were saying.  Did it get as far north as I thought it would? No.  The northern Shenandoah Valley, NOVA, DC area, WV panhandle, and central Maryland all got hung out to dry, literally  Ill go ahead and show you snow depth maps from the national weather service along with a few reported totals.

Ok lets start with the positives of the final call map.  The western half of my 4-8 inch range on my final call map worked out pretty well.  I outlined the 4-8 inch range on the snow depth map above.  I did hear varying reports of up to 4 or 5 inches outside of Richmond, particularly from well known MET DT, but I couldn't find any confirmation of this from the NWS (a lot of people have their theories but I won't go into that).  Anyways, ok... that part of the final call map was good.  Another positive was the "sweet spot" on my final call map.  As you can see above, outlined in red, the actual sweet spot from this storm wasn't too far off.  Overall, I think the western and southern part of my map verified pretty well.  Now time for the negatives, phew.  I had talked about the sharp gradient that was going to come from this storm.  I want to use Rockingham County where I live as an example.  Just outside of Grottoes (far south-eastern Rockingham county) reported up to 7.0 inches.  I live in Mcgaheysville, several miles away and got 4.5".  Matt lives in Harrisonburg, 10-15 miles from me where 2.0 inches was reported.  If you head to the northeastern portion of the county, only a dusting was reported.  The far northwestern portion of the county...nothing.  Absolutely no accumulation at all.  If you look on the map above and see the areas that I outlined in pink, you will see that no accumulating snow fell here at all, creating the biggest bust of my map.  Notice how closely it comes to the areas that got 4-8 inches.  Absolutely crazy.  The cold-dry air simply prevented enough moisture from getting into the northern areas, creating the dreaded virga storm for several hours.  The final bust area was south eastern Virginia (outlined in yellow) where temperatures cut back on snow fall.  The final band also didn't hold together as well as I thought it would, which was crucial because that was when the cold air was finally in place.  In conclusion, I do feel for those of you in northern areas  It killed me watching the band of snow essentially stop on a line just north of I-64.  I can only imagine what it did to you snow-lovers up there.  Any comments/suggestions/bashing/grades/etc. concerning our page, our forecast for the storm, what you liked/disliked about how we operated our page during the storm, and so on is encouraged so let us know.  Would love to hear what you think!  Also thanks to everyone who sent in pictures, snow reports, or discussed(or even argued) with me during the hours leading up to the storm...makes this page fun. -HV

No comments:

Post a Comment