Brick Tamland Posted January 13, 2015 Share Posted January 13, 2015 Closest weather station to my office in Raleigh says 38 and 38 right now. Link to comment Share on other sites More sharing options...
tarheelwx Posted January 13, 2015 Share Posted January 13, 2015 Seems we should be following wetbulb rather than dewpoint. TW Link to comment Share on other sites More sharing options...
mackerel_sky Posted January 13, 2015 Share Posted January 13, 2015 44/40 winning! Link to comment Share on other sites More sharing options...
downeastnc Posted January 13, 2015 Share Posted January 13, 2015 DP's in central VA starting to drop pretty good, DP is 11 in Fredricksburg and 23 in Richmond......just need that air to work its way into NC. Link to comment Share on other sites More sharing options...
FallsLake Posted January 13, 2015 Share Posted January 13, 2015 Seems we should be following wetbulb rather than dewpoint. TW Not necessarily, we're getting a feed of cold dry air into our region. The wet bulb would only tell us where we currently stand if no feed of air was present. **is that correct everybody? Link to comment Share on other sites More sharing options...
packfan98 Posted January 13, 2015 Author Share Posted January 13, 2015 Allan Huffman @RaleighWx 5 minutes agoWe may see sleet more widespread than originally thought across northern piedmont which could cut down on ice accrual. Allan Huffman @RaleighWx 4 minutes ago Right now that is just speculation, but the subfreezing layer is looking a little deeper than modeled in looking at some aircraft soundings. Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 Right now, it doesn't matter much. You'll want to look more closely at the wet bulb when precip starts. It's helpful to watch the temp and dewpoint progressions through the day. Both should come down. Link to comment Share on other sites More sharing options...
calculus1 Posted January 13, 2015 Share Posted January 13, 2015 My token readings from the automated airport site are hogwash. It's currently 37.9 F over 37 F IMBY; it's definitely not 43 F. Link to comment Share on other sites More sharing options...
superjames1992 Posted January 13, 2015 Share Posted January 13, 2015 One last Euro run before party time. Will it cause great consternation and panic? Link to comment Share on other sites More sharing options...
Brick Tamland Posted January 13, 2015 Share Posted January 13, 2015 Allan Huffman @RaleighWx 5 minutes agoWe may see sleet more widespread than originally thought across northern piedmont which could cut down on ice accrual. Allan Huffman @RaleighWx 4 minutes ago Right now that is just speculation, but the subfreezing layer is looking a little deeper than modeled in looking at some aircraft soundings. Central NC Weather @CentralNC_WX 9m9 minutes ago @RaleighWx On the other hand, could just result in more supercooled rain droplets and enhance ice accrual - tough call. Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 One last Euro run before party time. Will it cause great consternation and panic? Both? It's telling when nobody's posting any updated Rap or HRRR or Gem runs. Link to comment Share on other sites More sharing options...
thunderwolf Posted January 13, 2015 Share Posted January 13, 2015 I'm very much a newb at this stuff, but SREFs for RDU show 0.4" mean with 8 above, 11 below. Nearly all the below fall between .2" and .4" while most of the ones above are 0.6" to 1". Nearly all of it is shows as ZR (some IP). Is SREF out dated these days? Or otherwise, why wouldn't you have a consensus forecast a bit higher than the 0.1-0.25" predictions? There are a couple of factors as to why only looking at model QPF to determine icing amounts is not a good idea. The first is that with CAD setups we always lose some of the QPF due to evaporation. With our current setup with saturation in place, I don't expect this to be as dramatic as usual but drier air is coming. I would bank on losing about 0.05" of the model QPF to evaporation. The second factor is that you don't get 100% ice accrual rates until temperatures drop into the mid 20s. When temperatures are above that some the rain that falls runs off before it is able to freeze. The forecast right now calls for near freezing temperatures at the start of the precipitation so we will lose even more of the model QPF to runoff. I would say count on losing about 0.1" of the QPF for this reason. This number could be more or less depending on how far temperatures are able to drop. Finally, rate of precipitation can influence how much ice accretes. During times of heavier freezing rain, the actual amount of ice accrual is much less than 100% due to the large amounts of latent heat released. So if there are any convectively enhanced periods of precipitation, expect the actual icing totals to be reduced even further than the model forecasted QPF. When weather forecasting you must remember that the models are a very good tool. But you need to consider all factors before you make a forecasting decision. Link to comment Share on other sites More sharing options...
Solak Posted January 13, 2015 Share Posted January 13, 2015 ALERT: Wake County Schools cancels all athletic events, practices must conclude by 5:30 PM http://www.highschoolot.com/14352018 Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 Central NC Weather @CentralNC_WX 9m9 minutes ago @RaleighWx On the other hand, could just result in more supercooled rain droplets and enhance ice accrual - tough call. Who is that? Link to comment Share on other sites More sharing options...
packbacker Posted January 13, 2015 Share Posted January 13, 2015 Euro looks basically the same as 0z run. Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 Who is that? 1300m. Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 1300m.Oh cool! Link to comment Share on other sites More sharing options...
PackGrad05 Posted January 13, 2015 Share Posted January 13, 2015 One other factor to consider is that the roads around here still have water all over them... I'm looking out of a window right now and see puddles all over the street...... That stuff will start to freeze and cause added concerns. Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 Oh cool! Good met...didn't stay long over here, but knows his stuff. Link to comment Share on other sites More sharing options...
superjames1992 Posted January 13, 2015 Share Posted January 13, 2015 Euro looks basically the same as 0z run. Temps are really warm on the Euro. It is likely overdoing them, per usual, though. Link to comment Share on other sites More sharing options...
buckeyefan1 Posted January 13, 2015 Share Posted January 13, 2015 Good met...didn't stay long over here, but knows his stuff. Who liked to argue with himself then asked to be banned....several times Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 Who liked to argue with himself then asked to be banned....several times Yep that is true! Link to comment Share on other sites More sharing options...
jburns Posted January 13, 2015 Share Posted January 13, 2015 Who liked to argue with himself then asked to be banned....several times He was a strange one. I pictured him standing in front of his computer wearing ruby colored shoes and clicking his heels together three time while saying, "I want to get banned, I want to get banned, I want to get banned". Link to comment Share on other sites More sharing options...
superjames1992 Posted January 13, 2015 Share Posted January 13, 2015 Models take into account losing QPF to evaporation, BTW, so there's no need to correct for this unless you feel the dry air at the surface is underdone. Link to comment Share on other sites More sharing options...
WeatherExperiment Posted January 13, 2015 Share Posted January 13, 2015 NWS discussion looking to expand the frozen precip and warnings westward: AREA FORECAST DISCUSSIONNATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC1253 PM EST TUE JAN 13 2015.NEAR TERM /THROUGH TONIGHT/...1245 PM...STILL EVALUATING THE LATEST GUIDANCE FOR THE FREEZING RAINAND WINTRY MIX POTENTIAL TONIGHT. SEVERAL OBS IN AVERY COUNTY AREALREADY BELOW FREEZING...WHILE THE AREA RADARS SHOW EXPANSIVE LIGHTRETURNS (RA/DZ). SO MAY NEED TO EXPAND THE WINTER HAZARDS WEST TOTHE NC NRN BLUE RIDGE DUE TO FREEZING DRIZZLE. WILL HAVE THE NEXTUPDATE OUT BY 300 PM. Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 Over performing events FTW Link to comment Share on other sites More sharing options...
Pilotwx Posted January 13, 2015 Share Posted January 13, 2015 System lately have overperformed . 34 here Those in ENC the one thing that can cut totals down is latent heat release. If rain is to hard coming down Link to comment Share on other sites More sharing options...
Amos83 Posted January 13, 2015 Share Posted January 13, 2015 Quick question.... do the models take into account all the drizzle we are getting into their qpf totals? Here at the office it is has been a heavy drizzle all morning and continues. I'd imagine this type would be the best at accumulating once we get below freezing as it doesn't run off quickly. Link to comment Share on other sites More sharing options...
jburns Posted January 13, 2015 Share Posted January 13, 2015 Quick question.... do the models take into account all the drizzle we are getting into their qpf totals? Here at the office it is has been a heavy drizzle all morning and continues. I'd imagine this type would be the best at accumulating once we get below freezing as it doesn't run off quickly. Just my opinion, but I don't consider the model's precip totals to be accurate enough to where a few hours of drizzle would make much of a difference. Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 Link to comment Share on other sites More sharing options...
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