Final CASI Member Reports:
----
The snow has tapered to widely scattered flurries now (9pm Eastern) here
in
Auburn, NH. I received 6.6" of heavy, wet snow at my station. We had a
water
equivalent of 0.73" yielding a high snow density of 0.111g/cm^3. There
is
currently 10" of snow on the ground with still some drifts to 20" from
the
snow event and extensive blowing snow on 3/6 and 3/7. With 50s and
sunshine
coming this week, all of this snow will be history.
Brian Pevear
Auburn, NH
brianwp18{at}aol.com
----
From:
Pike School Closing and Severe Weather <sbccomp{at}sbccomputer.com>
Well, it was definately one of the stranger storms we've tracked in a
long
time....A foot or more a elevation (now melted almost completely!) and
almost nothing at river level.......
---NON-CASI Reports: Gary Gray of Millennium Weather's Storm Report:
From: "Gary E. Gray" <gdmgeg{at}smart.net> Organization: Millennium Weather To: wxobs-sne{at}shore.net, rlightbown{at}mfx.net Newsgroups: ne.weather
...Post Mortem; Some Success, Some Failure <3/15 9PM EST>...
Just to followup our recent event and our most significant event (as far as snow totals AND coverage combined) of this season, I'm just going to briefly look at what went right and what went wrong with my forecast and the situation in general.
As a general rule, given the complexity of the forecast, I'd like to think most folks did a decent job. Yes, there are certainly some folks in some areas who, because of what they received at their particular locale, don't believe that the forecasters did well at all. However, the model guidance was poor in its temperature profile forecasts and while some may argue that forecasters shouldn't rely on models so much, the very idea of trying to predict how many degrees the temperature may drop at a certain level due to dynamic cooling is simply a joke. It is only slightly less difficult trying to determine precisely what impact vertical mixing will have on the boundary layer. So, when model guidance provides no assistance in these matters, it's a virtual guessing game.
The perfect example of the above problem absolutely destroyed my prediction for far SE New England and Long Island. Saturday late morning the temperatures were in the mid to upper 30s with dewpoints in the 30s across this region (actually temps were in the low 40s in part of this area). This put the wet bulb temps in the mid-30s in this region. Even the Mid-Atlantic states were not that warm at the start of the event! Yes, much of the Mid-Atlantic was near 40 when the event began, but dewpoints were in the mid-20s for the most part. I knew dynamic cooling would lower temps in the column and SE New England was already starting colder than the Mid-Atlantic aloft. I also know that mixing would cool the boundary layer. But, frankly, I simply could not see things cooling by that much! I felt, with the dewpoints as high as they were, at best we'd see the temps drop to the dewpoints and SE New England would see temps lower only down to about 35F and this would keep them as mixed precip with little to no accumulation. Boy, was I wrong!! I haven't seen the absolute final numbers at this point, but at my last check I saw that Long Island and Cape Cod generally saw 5-10" of snow while the rest of SE Massachusetts and parts of Rhode Island saw 6-12"!!! This was tremendously more than I forsaw them receiving and this was certainly my greatest error in this storm forecast.
My second most significant error was a failure to predict the "backlash" snow in parts of the Mid-Atlantic for Monday AM. Kudos to the ETA model as it was predicting this backlash and it pretty much nailed the precipitation amounts associated with it. Honestly, though, I ignored the ETA. I have seen the models call for backlash snow so many times; I'd estimate that one in ten times it actually happens. It's like the boy who cried wolf! I just didn't believe the models. However, while I can explain my way around the error I made in SE NY and New England with the impossible to pin down temperature profiles, I honestly should have caught this backlash. Most forecasters did not, including myself. That was poor forecasting plain and simple. Why? Well, the reason the models tend to predict this type of snow and it rarely occurs is because a storm usually departs, taking its moisture with it long before the mid and upper level energy comes through. In this case, there was no question that the mid to upper level energy was coming in right after the sfc storm departed. As such, it should have been obvious that the moisture would still be in place, and the snow would start to fly! But, as with the boy who cried wolf, MOST forecasters dismissed the ETA out of hand without even looking into why it was calling for the snow. This was a fairly major error as a band of 4-8" snow (locally even heavier than that!) was dumped in portions of VA, MD, and WV. As the band moved east it weakened, but still put down 1-3" in the general vicinity of DC-BWI. So, this was the second significant error of the forecast for this storm.
All else, at least from my forecast, went rather well. I did have my heaviest band of snow a little too far east in S/C PA. I also extended the 1-3" band up into N and W NY a little too far. All in all, though, with the exception of the narrow swath in VA/WV/MD and the much heavier than predicted (by me) snow in SE New England and Long Island, all else went fairly well. For example, my steep gradient near Philly panned out excellently as I had Philly right on the border between 1-3" and 3-6", and they recieved 3-4". Meanwhile, not far north of the city, the recieved up to 8" of snow; this matched my tight gradient up into the 6-12" band quite nicely as well. Over interior E NY there were some unpredictably odd variations which threw me off by an inch or so in some locations... but not any more than that. One other thing I was pleased with was my more ENE to WSW orientation of the bands of accumulation. I did, unfortunately, make it (erroneously) a bit more NE to SW in my final update... but I was still somewhat ENE to WSW. This was nice to see since many folks were in fact orienting their snow accumulation contours incorrectly NE to SW. This was rather poor as it was clear from all data that the expected rain/snow line would take on an ENE to WSW orientation, not a NE to SW one. The other aspect of my forecast I was pleased with is that even though I did so somewhat at the last minute, I was in fact one of the first forecasters to back off of accumulations in the DC-BWI immediate metro area. Note that in my final update I put them in the 1-3" band; Baltimore got 2-3" (depending on where you went around the city), and Washington seemed to get about an inch or so (DCA only got 0.2"... not 2" as erroneously reported in one hourly... but thery are on the south side of the city, and typically run warm). So, I do take some gratification at properly nailing portions of the forecast. Unfortunately, I really did blow some other parts of the forecast.
So, that's about it in this event! Looks like the snow ought to melt and be gone in a pretty big hurry. Is this the end of winter? After the recent, infamous April Fool's Day blizzard in New England I don't dare say for certain that this is the end of it. However, I must say that there are no indications for a solid week or two that there will be any real cold air trying to make a run at the Northeast. So, the *may* well have been winter's last hurrah! **IF** that's the case, then I may well be done for this season! Those who have read my discussions for some time know that I don't tend to issue forecasts for severe Spring/Summer weather. Of course, though, I do put out my discussions for Atlantic tropical cyclones and I run my model, TRANTECH, on them. So, once that season gets going, it'll be time to get started again! Of course, I will also be putting out my seasonal Atlantic hurricane forecast sometime in April or May. And, FYI... make a note of this... sometime well before the hurricane season begins (probably in April) my web page will be moving to... http://www.millenniumweather.com At present, that web page is still under development, but it will be my home for this coming tropical season and beyond! Until then... unless Mother Nature deals us an ugly springtime winter storm (which we can never count out!)... have a good spring!!
-Gary
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