lsukev Posted January 26, 2015 Share Posted January 26, 2015 Just took a look at the RAP. Holy bustpotentialthatsnevergoingtohappen, batman! ETA: Most important NAM run in history starting up! Hopefully, we get NAM'd. I've heard this inverted trough thing is hard to predict... Link to comment Share on other sites More sharing options...
Bob Chill Posted January 26, 2015 Share Posted January 26, 2015 RAP h5 plots show the norlun/inv trough in a perfect spot 10z and 11z precip are similar. Here's 11z Link to comment Share on other sites More sharing options...
adelphi_sky Posted January 26, 2015 Share Posted January 26, 2015 Temp 31.5F Dewpoint 27.5. Light snow since about 6am. A dusting. Cars topped. Link to comment Share on other sites More sharing options...
MN Transplant Posted January 26, 2015 Share Posted January 26, 2015 I'd call it replacement rate snow right now. 32.9 Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted January 26, 2015 Share Posted January 26, 2015 RAP h5 plots show the norlun/inv trough in a perfect spot raph5.JPG 10z and 11z precip are similar. Here's 11z rapprecip.JPG Pretty please. Link to comment Share on other sites More sharing options...
WxUSAF Posted January 26, 2015 Author Share Posted January 26, 2015 RAP h5 plots show the norlun/inv trough in a perfect spot raph5.JPG 10z and 11z precip are similar. Here's 11z rapprecip.JPG I'm not sure I believe it, but I'll hug it anyway. Shows the precip picking up between about 22-5z in particular. We'll see. Looks like that's the only way to snatch victory from the jaws of defeat. Link to comment Share on other sites More sharing options...
Jebman Posted January 26, 2015 Share Posted January 26, 2015 32/29 with light rain and light snow mix. Precip coverage is dwindling a bit. Link to comment Share on other sites More sharing options...
weatherCCB Posted January 26, 2015 Share Posted January 26, 2015 RAP h5 plots show the norlun/inv trough in a perfect spot raph5.JPG 10z and 11z precip are similar. Here's 11z rapprecip.JPG Bob, I'm just hoping to beat my 3.75 from the clipper earlier this month. Link to comment Share on other sites More sharing options...
Mrs.J Posted January 26, 2015 Share Posted January 26, 2015 Baltimore County schools were already closed too, made for a really easy commute in. Nice. That is like when the Feds are off for a holiday and my husband wakes with a smile on his face knowing his commute into work will be a breeze. Link to comment Share on other sites More sharing options...
North Balti Zen Posted January 26, 2015 Share Posted January 26, 2015 In case anyone wants a primer on a Norlun Trough: http://www.mattnoyes.net/new_england_weather/2011/01/exactly-what-is-a-norlun-trough-and-how-do-you-forecast-weather-associated-with-it.html First, what is a "Norlun Instability Trough?" A trough is a weak disturbance in the atmosphere - in this case, near the surface - marked by lower surface barometric pressure that results from converging wind direction and speed. Surface convergence of air results in rising air (afterall, air converging at the surface must go either up or down, and clearly can't go into the ground), and rising air produces clouds and precipitation. Hence, troughs can focus locally heavier bands of precipitation. It was noted by operational forecasters Steve NOgueiRa and Weir LUNdstedt (Nor-Lun) that these troughs, when inverted (extending northwest from a surface low) and beneath a middle and upper level atmospheric cold pool, could result in very strong, localized bands of precipitation. On occasion, these narrow but intense bands of snow could produce in excess of one foot of snow, and largely were missed by computer guidance. Mr. Norgueira and Lundstedt both worked to find methods of forecasting these events, even when computer modeling missed them. Since their initial study in 1992, computer modeling has improved significantly, and these events often are projected in advance, though placement and intensity continues to be a challenge, especially in more complex setups. Link to comment Share on other sites More sharing options...
smokeybandit Posted January 26, 2015 Share Posted January 26, 2015 Hey, learn something new every day. I thought a Norlun had something to do with New Orleans. Link to comment Share on other sites More sharing options...
NorthArlington101 Posted January 26, 2015 Share Posted January 26, 2015 Holding on to greens. Very pretty, need those better rates or I fear my white will melt away until the afternoon. Link to comment Share on other sites More sharing options...
EastCoast NPZ Posted January 26, 2015 Share Posted January 26, 2015 Maybe up to 3/8" on the grass and elevated surfaces. Looks pretty much like the clipper fail from Tuesday. Sloppy, mangled mess that will vaporize almost instantaneously at the first lull. Link to comment Share on other sites More sharing options...
Bodhi Cove Posted January 26, 2015 Share Posted January 26, 2015 damn, hadn't looked out the window. sure is a dusting. that accumulated quickly. The Weber snow gauge. Took 35 minutes to lose sight of the Weber logo. (pics taken from 7:18-7:54 a.m.) Still snowing! Link to comment Share on other sites More sharing options...
lsukev Posted January 26, 2015 Share Posted January 26, 2015 If we get NAMed I'm going back home and calling in lol [.video=youtube;t3lshY4PwI4] [/video.] Link to comment Share on other sites More sharing options...
North Balti Zen Posted January 26, 2015 Share Posted January 26, 2015 Why is Norlun Trough position sometimes difficult to forecast? The advancement of atmospheric modeling technology in the 2000s has vastly improved the ability to forecast location of Norlun Troughs. There are a few issues that still are significant obstacles to the operational forecaster, however, most noteably total precipitation amount (QPF forecast) and placement/development of Norlun troughs when more than one inverted trough is involved. Link to comment Share on other sites More sharing options...
Jebman Posted January 26, 2015 Share Posted January 26, 2015 In case anyone wants a primer on a Norlun Trough: http://www.mattnoyes.net/new_england_weather/2011/01/exactly-what-is-a-norlun-trough-and-how-do-you-forecast-weather-associated-with-it.html Thanks Balti Zen, I love pdfs, ESPECIALLY about weather Link to comment Share on other sites More sharing options...
lsukev Posted January 26, 2015 Share Posted January 26, 2015 Latest HRRR looks excellent for DC starting around 4pm. All snow under a good band from the coastal. 3-4" near DCA and still coming down at the end of its run. Link to comment Share on other sites More sharing options...
WVclimo Posted January 26, 2015 Share Posted January 26, 2015 Light snow and 26. Radar isn't really picking up what is falling here. Maybe because it's primarily needles ? The crossed needles are cool though. Perfect X's. 0.8" of new snow on the ground. 2" snow depth in the yard. Link to comment Share on other sites More sharing options...
lsukev Posted January 26, 2015 Share Posted January 26, 2015 Latest RAP bullseyes Jebman with over 6 inches. Looks close to last run, just a little south. Maybe it's believable?? Link to comment Share on other sites More sharing options...
Pityflakes Posted January 26, 2015 Share Posted January 26, 2015 Looks like that's or for the "front end" in DC. It's warm. Need rates and lucky placement this afternoon. Link to comment Share on other sites More sharing options...
Kmlwx Posted January 26, 2015 Share Posted January 26, 2015 Latest RAP bullseyes Jebman with over 6 inches. Looks close to last run. Maybe it's believable?? Maybe...tho the RAP and HRRR have that tendency to look super consistent only to pull the rug out once it's like 3 hours out. I'll believe it when I see it but the consistency is intriguing. Link to comment Share on other sites More sharing options...
yoda Posted January 26, 2015 Share Posted January 26, 2015 NAM looks good to me through 00z Link to comment Share on other sites More sharing options...
BTRWx Posted January 26, 2015 Share Posted January 26, 2015 Looks like that's or for the "front end" in DC. It's warm. Need rates and lucky placement this afternoon. NAM shows things filling in in a couple hours or so. eta: It is warm though. Link to comment Share on other sites More sharing options...
Jebman Posted January 26, 2015 Share Posted January 26, 2015 Latest RAP bullseyes Jebman with over 6 inches. Looks close to last run, just a little south. Maybe it's believable?? I'll hug it BUT I will keep my expectations at a dusting to an inch. It may be believable, maybe not lol. Link to comment Share on other sites More sharing options...
mitchnick Posted January 26, 2015 Share Posted January 26, 2015 light snow here with a 1/2" on rooftops and cars Link to comment Share on other sites More sharing options...
snowfan Posted January 26, 2015 Share Posted January 26, 2015 NAM might not have the same coverage as the RAP/HRRR, but its showing persistent bands so far thru h15. Link to comment Share on other sites More sharing options...
Kmlwx Posted January 26, 2015 Share Posted January 26, 2015 NAM might not have the same coverage as the RAP/HRRR, but its showing persistent bands so far thru h15. I'm going to pull the (in)famous weenie statement that the RAP and HRRR are going to be right because they have better resolution Link to comment Share on other sites More sharing options...
yoda Posted January 26, 2015 Share Posted January 26, 2015 Looks like 12z NAM wraps up for us just after or around midnight Link to comment Share on other sites More sharing options...
NinjaWarrior2 Posted January 26, 2015 Share Posted January 26, 2015 Looks like newest RAP is not as good for DC, okay/better for Baltimore. Link to comment Share on other sites More sharing options...
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