Amped Posted February 17, 2018 Share Posted February 17, 2018 3 minutes ago, clskinsfan said: That is a nasty cutoff on the NAMs. Still holding on to the idea of a split precip shield for some reason? Yeah looks more like what the RGEM was showing if you discount the southern bad as sleet and rain. Link to comment Share on other sites More sharing options...
pasnownut Posted February 17, 2018 Share Posted February 17, 2018 11 minutes ago, Ji said: 13 minutes ago, clskinsfan said: That is a nasty cutoff on the NAMs. Still holding on to the idea of a split precip shield for some reason? Why the hell is there a split precip shield. Why can't we just get a normal event?? Gotta admit, it is "interesting". Not sure based on storm evolution, that it would play out like that. I'd think it would fill in/smooth out as there is no transfer or coastal redevelopement where it is being depicted. Link to comment Share on other sites More sharing options...
psuhoffman Posted February 17, 2018 Share Posted February 17, 2018 5 minutes ago, Ji said: 6 minutes ago, clskinsfan said: That is a nasty cutoff on the NAMs. Still holding on to the idea of a split precip shield for some reason? Why the hell is there a split precip shield. Why can't we just get a normal event?? There is banding with every storm. The qpf difference is only .3 qpf between the bands and around .5 in them. But when it's a short duration thump snow with a marginal temp setup that's a big deal. Normally we would think nothing of it. Link to comment Share on other sites More sharing options...
clskinsfan Posted February 17, 2018 Share Posted February 17, 2018 5 minutes ago, Warm Nose said: Corrected map I think that looks fine. Maybe some lolli's of 4 inches mixed in there. Link to comment Share on other sites More sharing options...
SnowGolfBro Posted February 17, 2018 Share Posted February 17, 2018 I wish it was as simple as the cold air is flooding in and precip was on the doorstep. Nah that wouldn’t be as much fun Link to comment Share on other sites More sharing options...
usedtobe Posted February 17, 2018 Share Posted February 17, 2018 Here's a forecast nightmare. Both the 12- and 3KM NAM precipitation algorithms have my house in snow through 21Z (6PM) and then have a changeover at 00Z. Essentially the model has its precipitation thump right over my house and by 00Z has me in almost 0.50" liquid. The temp lowers to 33 during the heavy snow but that is based on the strong vertical motion and precipitation falling. That would bust our forecast low but the two NAMS are colder than the other guidance and the NAM has a high bias for precipitation so its amounts may be overdone. Lighten the amounts and the surface temp and vertical temperature profile might b3 warmer. Below is the sounding at 00Z over my house. Note the temp at 00Z is isothermal (doesn't change with height) through a deep layer and is just above freezing. I'm rooting for it even though it would bust our CWG forecast (sorry Jason) but also don't trust it and am not sure I'd change the forecast at this stage. We still have time to make changes tomorrow since the precipitation won't be coming in until later in the afternoon. As I said earlier, this forecast is a bust waiting to happen and we don't even know which way it might bust. Isuspect that the Euro and GFS will have warmer temps aloft. Oh well, good luck Ian who is doing the forecast tonight. Link to comment Share on other sites More sharing options...
Bob Chill Posted February 17, 2018 Share Posted February 17, 2018 Yea Wes, the nams complicated things with a combination of precip stripe maxes and very borderline temps at times in different places. 0z has all the fresh sounding data ingested too. My guess from the beginning was 2-3" in my yard but now it looks like bad luck could keep me under 2 and good luck could break 3. Nowcast obs tomorrow are going to stress me out. Lol Link to comment Share on other sites More sharing options...
Eskimo Joe Posted February 17, 2018 Share Posted February 17, 2018 20 minutes ago, Ji said: 22 minutes ago, clskinsfan said: That is a nasty cutoff on the NAMs. Still holding on to the idea of a split precip shield for some reason? Why the hell is there a split precip shield. Why can't we just get a normal event?? Because this is the Snowhole of America Link to comment Share on other sites More sharing options...
Bob Chill Posted February 17, 2018 Share Posted February 17, 2018 I can't say I've seen many divided 850s like this with the low tracking south either. Unusual to see below freezing 850s to the south close to the low and then a strip of above freezing embedded to the north. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted February 17, 2018 Share Posted February 17, 2018 Quote Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 959 PM EST Fri Feb 16 2018 .SYNOPSIS... An area of high pressure will briefly build north of the region overnight. A wave of low pressure will pass to the southeast Saturday. A second area of high pressure will return briefly again on Sunday before another storm system approaches from the west early next week. && .NEAR TERM /THROUGH SATURDAY/... Gusty northwest winds behind a passing cold front will diminish overnight as colder air moves in as well. Temperatures as of 930 pm range from 52 in St. Marys County in southeast Maryland to 36 in Allegany County in western Maryland. Expect temperatures to continue to fall throughout the rest of the night. High clouds will build into the region Saturday ahead of a developing coastal low pressure system. Cold air in place with dewpoint temperatures in the teens will evolve ahead of the next wave of precipitation. This wave consists of a mix of snow and sleet for the most part from southwest to northeast. There is a hint of some light freezing rain, mainly across parts of the Central Shenandoah Valley late Saturday morning into Saturday afternoon. Snow and sleet could accumulate between 1 and 3 inches with a glaze to less than one tenth of an inch of ice due to some freezing rain. The farther northern and northeastern zones and near the Mason-Dixon line will encounter more snow than sleet due to colder surface temperatures. Winter Weather Advisories are in effect across the northwestern two-thirds of our region with a Winter Storm Watch in effect over the western ridges of western Maryland, western West Virginia and western Virginia. There will be a light accumulation of snow and sleet to the southeast of our Advisories in the Metropolitan areas and into southern Maryland with a higher emphasis on a mix of snow and rain or sleet and rain becoming all rain later Saturday. The precipitation will end from southwest to northeast across the region later Saturday evening, most likely ending and moving out of the region around midnight. High pressure will build in behind the departing precipitation and its affiliated low pressure system overnight Saturday night. Temperatures will be chilly Saturday night. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... The precipitation will end from southwest to northeast across the region later Saturday evening, most likely ending and moving out of the region around midnight. High pressure will build in behind the departing precipitation and its affiliated low pressure system overnight Saturday night. Temperatures will be chilly Saturday night. High pressure will influence a lot of sunshine and quickly modifying temperatures Sunday with highs reaching about 10 degrees milder than Saturday's highs. A return flow will develop Sunday night as high pressure moves east. Moisture and temperatures will be on the increase throughout Sunday night. Link to comment Share on other sites More sharing options...
yoda Posted February 17, 2018 Share Posted February 17, 2018 2 minutes ago, Bob Chill said: I can't say I've seen many divided 850s like this with the low tracking south either. Unusual to see below freezing 850s to the south close to the low and then a strip of above freezing embedded to the north. Yes, def agree. Hopefully it will come together - as in the 850 division - it would be odd to see places like Manassas get 4 inches and Leesburg 2 inches because of the way the 850s are set up Link to comment Share on other sites More sharing options...
Interstate Posted February 17, 2018 Share Posted February 17, 2018 We never know. Temp tomorrow might get above what is predicted and then everything is just rain Link to comment Share on other sites More sharing options...
yoda Posted February 17, 2018 Share Posted February 17, 2018 1 minute ago, Interstate said: We never know. Temp tomorrow might get above what is predicted and then everything is just rain Doubtful for the entire CWA Link to comment Share on other sites More sharing options...
Ji Posted February 17, 2018 Share Posted February 17, 2018 cant wait for our weak to moderate Nino this year. This winter is just the worst lol Link to comment Share on other sites More sharing options...
nj2va Posted February 17, 2018 Share Posted February 17, 2018 B&W crayon RGEM maps show a 30 mm bullseye in the DC area for the 12 hour precip. I’m probably reading it wrong since I need a PhD to decipher it . No idea on 850s, etc until the better maps... Link to comment Share on other sites More sharing options...
usedtobe Posted February 17, 2018 Share Posted February 17, 2018 6 minutes ago, Bob Chill said: I can't say I've seen many divided 850s like this with the low tracking south either. Unusual to see below freezing 850s to the south close to the low and then a strip of above freezing embedded to the north. It all depends on where the thump ends up which will probably continue to jump a bit from run to run. I also think the NAM may be too wet which could keep the temp profile a tad too cold. Link to comment Share on other sites More sharing options...
Bob Chill Posted February 17, 2018 Share Posted February 17, 2018 Icon hates Ji's and strongly dislikes my yard. Lol Link to comment Share on other sites More sharing options...
usedtobe Posted February 17, 2018 Share Posted February 17, 2018 7 minutes ago, yoda said: Yes, def agree. Hopefully it will come together - as in the 850 division - it would be odd to see places like Manassas get 4 inches and Leesburg 2 inches because of the way the 850s are set up It would be odd but I can remember a forecast I made in Missouri where the heavy precipitation kept a pocket of really heavy snow where it should have been warmer than where it was raining but where it was raining but that one pocket ofS+ was the heaviest precip around so it can happen. I sure wouldn't bet on it and right now would go towards climo along with the worry that the temps may never quite lower as much as forecast by the models. Link to comment Share on other sites More sharing options...
Interstate Posted February 17, 2018 Share Posted February 17, 2018 ICON is not happy tonight Link to comment Share on other sites More sharing options...
Ji Posted February 17, 2018 Share Posted February 17, 2018 2 minutes ago, Bob Chill said: Icon hates Ji's and strongly dislikes my yard. Lol this whole has shown up on every storm this year...no matter what direction its coming from Link to comment Share on other sites More sharing options...
Ji Posted February 17, 2018 Share Posted February 17, 2018 the icon has some value in the long range but way too jumpy to be a tool you can forecast with. Link to comment Share on other sites More sharing options...
psuhoffman Posted February 17, 2018 Share Posted February 17, 2018 18 minutes ago, Bob Chill said: I can't say I've seen many divided 850s like this with the low tracking south either. Unusual to see below freezing 850s to the south close to the low and then a strip of above freezing embedded to the north. It's more typical of a spring storm where the mid levels have to be cooled by dynamics. Link to comment Share on other sites More sharing options...
WEATHER53 Posted February 17, 2018 Share Posted February 17, 2018 Baro almost soaring in last 8 hours, +0.45. We are going to have less cold air problems tha models showed kinda hard to buy into after 60's today but D.C. Is disproportionate in 60 one day and then snow in 24-36 Link to comment Share on other sites More sharing options...
peribonca Posted February 17, 2018 Share Posted February 17, 2018 Gfs 850s look terrible. Link to comment Share on other sites More sharing options...
MD Snow Posted February 17, 2018 Share Posted February 17, 2018 GFS holds it's ground. ICON looks similar to the GFS. NAM's have warmed up a good bit in the upper levels. Unless the EURO holds it's ground tonight...I think this is really a DCA/Balt up 95 north and west storm with little if any accumulations south and east. I know the GFS has played catchup in terms of precip/track with this one but it's been pretty steady with the idea of a warmer storm. Link to comment Share on other sites More sharing options...
Ji Posted February 17, 2018 Share Posted February 17, 2018 well..as we say in DC best.... NEXT Link to comment Share on other sites More sharing options...
Jandurin Posted February 17, 2018 Share Posted February 17, 2018 well..as we say in DC best.... NEXT WINTER fixed that for you Link to comment Share on other sites More sharing options...
MD Snow Posted February 17, 2018 Share Posted February 17, 2018 I'm sure there will be some surprises tomorrow though. Could have someone south and east get under a band early on and pick up a quick couple of inches but that's probably the only way they end getting anything substantial. Link to comment Share on other sites More sharing options...
Maestrobjwa Posted February 17, 2018 Share Posted February 17, 2018 3 minutes ago, Jandurin said: fixed that for you Not yet...gotta wait to see how late Feb/early March shakes out. All we can ask for is chances in this darn corridor...so let's see if we can roll the dice a few more times. But as for this event...I already started to mentally toss it away once I saw the split precip bands, lol (It's not too disappointing since it was never forecasted to be more than a couple inches in the first place!) Link to comment Share on other sites More sharing options...
Kevin Reilly Posted February 17, 2018 Share Posted February 17, 2018 GFS Says nothing up this way too just outside of Philadelphia in Delaware County Link to comment Share on other sites More sharing options...
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