CoastalWx Posted March 17, 2014 Share Posted March 17, 2014 The euro at 12z yesterday did an excellent job..better than the 12z GFS I thought. I know the euro was sort of playing catch up, but if I had to write a forecast, I sure would have sided with the euro if I wanted snow. GFS was too bullish with the nrn extent of snow into NJ it seemed, but not too surprised since the euro and NAM had the sharp cutoff which may owe to their resolution. I know the overall mid level features were there on the models and the deformation and frontogenesis were spot on for the most part. I think the difference even within the GFS and NAM runs were how most the mid levels were. There were times where the 850-500 VV/RH progs weren't very appealing in my eyes..especially before 00z yesterday. That may have to do with any convection to the south robbing any mid level moisture and overall the 500mb s/w look.That changed yesterday as the models got bullish there. I didn't have to forecast that area this time around...just something I noticed as a casual bystander. Even the HRRR yesterday was unsure with it's progged weakening of the snow bands, but it finally got a clue by evening. However, the key as always is finding those deformation zones. Like HM said..if QPF looks light, but you have that classic 700mb low crossing near or just south (even a back bent warm front or trough axis)...you may want to act accordingly. We had the most textbook display of this here on 1/21. ).5" QPF and 18" of snow in spots. Why? because the 700mb WF was overhead and it just become a frontogenetic band of snow that dumped. If nothing else, those srn stream systems have incredible deformation zones because they are PWAT monsters. All that moisture gets squeezed out. I should state..the QPF did add up, but I think models (perhaps the GFS especially) were a little too light after 6z. This is when we had the forcing go nuts. Link to comment Share on other sites More sharing options...
Deck Pic Posted March 17, 2014 Share Posted March 17, 2014 I should state..the QPF did add up, but I think models (perhaps the GFS especially) were a little too light after 6z. This is when we had the forcing go nuts. banding was really tasty...I did best from around 11-12 and then around 3-5, though never really did worse than ~0.5"/hr sometime between 11 and 12 I picked up around 1.5" in 40-45 minutes and then around 2.25" between 3 and 5....have to go back and check to be certain... Link to comment Share on other sites More sharing options...
HM Posted March 17, 2014 Share Posted March 17, 2014 We all expected the QPF, the wild card was how fast the cooling took place. We should have given more credence to the low dewpoints, they were lower than march 3rd. I think a more gradual cooling would have worked out with a more typical shield of precipitation, like 3/3. The dewpoints are of course important but kind of a red herring too. The heavier bands were really the force that accelerated the cooling. But I do agree that the deep-layer <32 WB and low DPs made it nearly instant; so, I guess it was the super tag team. It's hard to make a dewpoint comparison to 3/3 because of how multifaceted it was. Several different forcings came through over a longer duration, none of which as strong as yesterday. But the general advection of low-mid level dry air on 3/3 and cold air when the confluence zones were overhead is more detrimental to snow than starting off yesterday with a lower dewpoint. As usual, it's always about the differential advection processes and moist mid levels for when deformation zones matter. Link to comment Share on other sites More sharing options...
CoastalWx Posted March 17, 2014 Share Posted March 17, 2014 banding was really tasty...I did best from around 11-12 and then around 3-5, though never really did worse than ~0.5"/hr sometime between 11 and 12 I picked up around 1.5" in 40-45 minutes and then around 2.25" between 3 and 5....have to go back and check to be certain... I know..that was a sweet band there. Jesus...I went back and looked. Another thing to take home is that sometimes the best model isn't the best model 48 hrs or so out. I probably would have given more "weight" to the euro before 00z yesterday...but that is also why we have various other models at our disposal. Past doesn't always dictate future, nor does performance in other regions. The GFS didn't do great up here last weekend for the NNE snowbomb, but that doesn't mean it's going to do a lousy job with your storm. We love to side with the euro on many storms..myself included, but sometimes it's not the best. The GFS was consistent which was a red flag..the euro kept ticking north bit by bit. Of course the ECMWF M.O. is to never jump wildly like the GFS can at times, but the GFS was pretty darn consistent. I do wish it handled the situation better after 06z last night. I tip my cap to the euro there and it won the near term. Link to comment Share on other sites More sharing options...
WEATHER53 Posted March 17, 2014 Share Posted March 17, 2014 From 11:45pm to 12 midnight I got creamed with 0.75" in 15 minutes, 1" in half hour. Don't think I had a burst like that in any other snow events this season. All time 15 minute record for me is 1.25" in 15 minutes during thundersnow 1983. Link to comment Share on other sites More sharing options...
CoastalWx Posted March 17, 2014 Share Posted March 17, 2014 3/3 had that PV lobe pressing SE too. It never slowed despite the low coming up from the south. Just showed no mercy. Link to comment Share on other sites More sharing options...
Deck Pic Posted March 17, 2014 Share Posted March 17, 2014 3/3 had that PV lobe pressing SE too. It never slowed despite the low coming up from the south. Just showed no mercy. 3/3 was an awesome storm for so many reasons despite the lower totals (4" for me), but much of the storm was so frustrating...watching it snow nice and steady for an hour, going outside and realizing you just tacked on 0.3". Link to comment Share on other sites More sharing options...
MillvilleWx Posted March 17, 2014 Share Posted March 17, 2014 The euro at 12z yesterday did an excellent job..better than the 12z GFS I thought. I know the euro was sort of playing catch up, but if I had to write a forecast, I sure would have sided with the euro if I wanted snow. GFS was too bullish with the nrn extent of snow into NJ it seemed, but not too surprised since the euro and NAM had the sharp cutoff which may owe to their resolution. I know the overall mid level features were there on the models and the deformation and frontogenesis were spot on for the most part. I think the difference even within the GFS and NAM runs were how most the mid levels were. There were times where the 850-500 VV/RH progs weren't very appealing in my eyes..especially before 00z yesterday. That may have to do with any convection to the south robbing any mid level moisture and overall the 500mb s/w look.That changed yesterday as the models got bullish there. I didn't have to forecast that area this time around...just something I noticed as a casual bystander. Even the HRRR yesterday was unsure with it's progged weakening of the snow bands, but it finally got a clue by evening. However, the key as always is finding those deformation zones. Like HM said..if QPF looks light, but you have that classic 700mb low crossing near or just south (even a back bent warm front or trough axis)...you may want to act accordingly. We had the most textbook display of this here on 1/21. ).5" QPF and 18" of snow in spots. Why? because the 700mb WF was overhead and it just become a frontogenetic band of snow that dumped. If nothing else, those srn stream systems have incredible deformation zones because they are PWAT monsters. All that moisture gets squeezed out. Wow, thanks for that tidbit Coastal. That makes a ton of sense. Earlier on one of the runs on Saturday, I think it was the 18 or 0z NAM showed a great signature of the 700 mb low and classic VV's setting up banding potential between BWI-IAD-DCA. I think it was Mitch or Matt put out the text profiles from that run for BWI and DCA and both outputs indicated classic setup for banding potential between those 2 zones. On the other hand, banding potential is great for those in it and horrible for those around it due to subsidence/sinking air aloft robbing any chance for desirable precip. That actually was the case partly last night as those of us north of Baltimore were struggling to find any rates good enough to get accumulating snow and Bob Chill. Matt, Ian and the DC gang to the N/NW suburbs were getting smacked hard. It wasn't till around midnight that preicp shield started to extend northward as the mid-levels started to cooperate better overcoming the CAA aloft. I was beginning to write off any chances of good preicp up this way and man did I end up being wrong and lesson learned. Great to hear you and HM's insight for these storms because it helps everyone learn a lot. Thanks a billion. You guys are always welcome here in my book Link to comment Share on other sites More sharing options...
CoastalWx Posted March 17, 2014 Share Posted March 17, 2014 3/3 was an awesome storm for so many reasons despite the lower totals (4" for me), but much of the storm was so frustrating...watching it snow nice and steady for an hour, going outside and realizing you just tacked on 0.3". You guys had some pretty awesome storms. None of this legit car topper crap...I mean thumps, deformation bands..you name it. Even thunder. Kind of puts a funny (*) to the normal EOFs or thinking that we have for +NAOs. Link to comment Share on other sites More sharing options...
CoastalWx Posted March 17, 2014 Share Posted March 17, 2014 Wow, thanks for that tidbit Coastal. That makes a ton of sense. Earlier on one of the runs on Saturday, I think it was the 18 or 0z NAM showed a great signature of the 700 mb low and classic VV's setting up banding potential between BWI-IAD-DCA. I think it was Mitch or Matt put out the text profiles from that run for BWI and DCA and both outputs indicated classic setup for banding potential between those 2 zones. On the other hand, banding potential is great for those in it and horrible for those around it due to subsidence/sinking air aloft robbing any chance for desirable precip. That actually was the case partly last night as those of us north of Baltimore were struggling to find any rates good enough to get accumulating snow and Bob Chill. Matt, Ian and the DC gang to the N/NW suburbs were getting smacked hard. It wasn't till around midnight that preicp shield started to extend northward as the mid-levels started to cooperate better overcoming the CAA aloft. I was beginning to write off any chances of good preicp up this way and man did I end up being wrong and lesson learned. Great to hear you and HM's insight for these storms because it helps everyone learn a lot. Thanks a billion. You guys are always welcome here in my book Here is the 1/21 look we had. Notice the convering wind vectors over SNE. We have no strong s/w, no CCB...just good fronto forcing. That's all it takes. Link to comment Share on other sites More sharing options...
MillvilleWx Posted March 17, 2014 Share Posted March 17, 2014 Here is the 1/21 look we had. Notice the convering wind vectors over SNE. We have no strong s/w, no CCB...just good fronto forcing. That's all it takes. avn_06_700.gif RAD_KBOX_N0R_ANI.gif I remember that event for you guys up there. You guys got slammed there in SNE south of Boston with like 16-24" I believe. That is impressive with that setup. Frontogen is definitely a favorite of mine. Thanks for sharing that. I will remember to take that into consideration next time for an impending system. Often times gets over looked in the wash of boundary layer temps and surface reflections (ie. ground temps). I knew it would be cold enough, but was too worried about the dry air aloft to see the bigger picture Link to comment Share on other sites More sharing options...
famartin Posted March 17, 2014 Share Posted March 17, 2014 Isn't it a little weird that the three airports had the same peak snow depth but considerably different snowfall totals? Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted March 17, 2014 Share Posted March 17, 2014 Only lost 1.5 inches today on the south facing deck on my house, that's about as little as you can lose here on march 17 I think Link to comment Share on other sites More sharing options...
Deck Pic Posted March 17, 2014 Share Posted March 17, 2014 DCA adjusted? IAD - 11.1 DCA - 6.7 BWI - 8.1 Link to comment Share on other sites More sharing options...
WEATHER53 Posted March 17, 2014 Share Posted March 17, 2014 6pm obs: 28.5F, radiant about done at 33.9, solid 6" remaining generally. When is the next one? Link to comment Share on other sites More sharing options...
Deck Pic Posted March 17, 2014 Share Posted March 17, 2014 DCA adjusted? IAD - 11.1 DCA - 6.7 BWI - 8.1 lol BWI may have been adjusted down to 7.2" Link to comment Share on other sites More sharing options...
gymengineer Posted March 17, 2014 Share Posted March 17, 2014 DCA adjusted? IAD - 11.1 DCA - 6.7 BWI - 8.1 IAD might have been too... it's iffy whether they could have picked up 1.1" after 8 am. Any other reports from around there for the 8 am to 2 pm period? Link to comment Share on other sites More sharing options...
Deck Pic Posted March 17, 2014 Share Posted March 17, 2014 seems like IAD is never adjusted down, reports a more than coincidental amount of "lazy" totals (rounded), has its share of overmeasurements (1/21), and has its liquid adjusted when warranted... Link to comment Share on other sites More sharing options...
Deck Pic Posted March 17, 2014 Share Posted March 17, 2014 IAD might have been too... it's iffy whether they could have picked up 1.1" after 8 am. Any other reports from around there for the 8 am to 2 pm period? reporting 16.0" on month now Link to comment Share on other sites More sharing options...
Stormpc Posted March 17, 2014 Share Posted March 17, 2014 Light frozen plates and zr falling now. May cause issues later tonight if it keeps up. 29.0 Link to comment Share on other sites More sharing options...
Yeoman Posted March 17, 2014 Share Posted March 17, 2014 Flurries in DC Link to comment Share on other sites More sharing options...
Swiscaster Posted March 17, 2014 Share Posted March 17, 2014 Only lost 1.5 inches today on the south facing deck on my house, that's about as little as you can lose here on march 17 I think I was thinking the same thing. Took a drive this afternoon and was shocked at how wintry it still looked. Cloudy, 30 degrees, snow still on trees/bushes, icicles on roofs, etc. March 17th! Not our typical March snow. Are we breaking record low maximums today? Link to comment Share on other sites More sharing options...
StudentOfClimatology Posted March 17, 2014 Share Posted March 17, 2014 Is this some sort of stratiform precip? I'm too lazy to look at the soundings/analysis. A few flakes mixed in with tiny ice pellets..maybe some drizzle too.. Link to comment Share on other sites More sharing options...
gymengineer Posted March 17, 2014 Share Posted March 17, 2014 reporting 16.0" on month now Wait, DCA is still showing 11" for the month... yesterday's total got adjusted to 3.8", right? Or am I missing something very obvious... Link to comment Share on other sites More sharing options...
yoda Posted March 17, 2014 Share Posted March 17, 2014 DCA adjusted? IAD - 11.1 DCA - 6.7 BWI - 8.1 Jason said he checked and its still 7.2 Kat77 5:45PM Does anyone know why DCA lowered their total from 7.2 to 6.7? More nonsense from National, just wanted to know if anyone had an explanation. Notice the 3.4 today and yesterday's 3.3 is now the new total. http://www.nws.noaa.gov/climate/getclimate.php?wfo... LikeReportReply Jason-CapitalWeatherGang 6:23 PM EST They didn't. I saw this too and called the local NWS office . Those statements are messed up. From the comments section -- http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2014/03/17/pm-update-clouds-in-no-major-hurry-to-fully-depart-todays-cold-is-quite-rare/ Link to comment Share on other sites More sharing options...
Deck Pic Posted March 17, 2014 Share Posted March 17, 2014 Wait, DCA is still showing 11" for the month... yesterday's total got adjusted to 3.8", right? Or am I missing something very obvious... Jason said he checked and its still 7.2 yes...the 4th CLI issued in the last 2 hours has seemed to correct the seasonal, yet not the daily?...DCA still reporting 3.3 yesterday and 3.4 today? yet 11.0" on month? Link to comment Share on other sites More sharing options...
gymengineer Posted March 17, 2014 Share Posted March 17, 2014 yes...the 4th CLI issued in the last 2 hours has seemed to correct the seasonal, yet not the daily?...DCA still reporting 3.3 yesterday and 3.4 today? yet 11.0" on month? If you go to the "archived data" and click yesterday's CLI, you'll see they adjusted yesterday's total to 3.8" in an update released 4 pm today. Link to comment Share on other sites More sharing options...
steinweather Posted March 17, 2014 Share Posted March 17, 2014 I measured 10 in. on my deck in Rehoboth Beach, DE. Light snow showers just stopped around 6PM Link to comment Share on other sites More sharing options...
Deck Pic Posted March 17, 2014 Share Posted March 17, 2014 yes...the 4th CLI issued in the last 2 hours has seemed to correct the seasonal, yet not the daily?...DCA still reporting 3.3 yesterday and 3.4 today? yet 11.0" on month? saw that it was fixed 5 CLI's ago at 4pm Link to comment Share on other sites More sharing options...
Swiscaster Posted March 17, 2014 Share Posted March 17, 2014 Fairfax County Schools 2-hour delay tomorrow. Roads are in impeccable shape! Link to comment Share on other sites More sharing options...
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