downeastnc Posted January 13, 2015 Share Posted January 13, 2015 Even with the models backing off on totals, that's still a lot of moisture building to our south (even if it is light). We need to get these temps to drop below freezing and we can still have at least an interesting event. **dew point down to 21 in Farmville VA, teens at Richmond. . Lets see if the sun setting might be good enough to get temps down a few degrees most places....36 over 34 here in Greenville need that DP to slide on down Link to comment Share on other sites More sharing options...
Isopycnic Posted January 13, 2015 Share Posted January 13, 2015 DP finally below freezing 31.7f Link to comment Share on other sites More sharing options...
FallsLake Posted January 13, 2015 Share Posted January 13, 2015 I know it's late, but the gfs looked slightly better for the triangle I believe. Never too late to join the party. That would put areas from Raleigh south and east > .24 **it would give me my .1 to .15 win... Link to comment Share on other sites More sharing options...
Solak Posted January 13, 2015 Share Posted January 13, 2015 We still got a ways to go... it's still 34 in DC, 35 in Charlottesville, and 38 in Petersburg right now. Link to comment Share on other sites More sharing options...
FallsLake Posted January 13, 2015 Share Posted January 13, 2015 We still got a ways to go... it's still 34 in DC, 35 in Charlottesville, and 38 in Petersburg right now. But their dew points are in the teens. Once you start to saturate the air the temps will drop fast. RDU now 37/29 Link to comment Share on other sites More sharing options...
tarheelwx Posted January 13, 2015 Share Posted January 13, 2015 Again, shouldn't we be tracking wetbulb rather than strictly looking at temp or dewpoint? Charlottesville wetbulb is 26. TW Link to comment Share on other sites More sharing options...
HKY_WX Posted January 13, 2015 Share Posted January 13, 2015 It's interesting, but if you've been through enough storms in this area, you see a pattern w/ the people here. The day before everyone get's amped over the HI-RES NAM/WRF combo's (our in house say's so and so)... Then w/in the 12 hours before anything starts the models start converging on something reasonable and everyone's emotions go into the toilet and believe we'll get nothing. It get's tiring after seeing it for the past decade lol. Anyways I think RDU looks good for a solid .2 or so of zr late tonight/tomorrow morning with a dusting of sleet on the grass/roads. Temps will struggle to get above freezing tomorrow w/ the cad/soupy airmass in place and there will not be any WAA due to the SLP being offshore. So freezing drizzle will be an issue tomorrow too. Overall I think it will be a decent system and cause lots of issues tomorrow morning on the roads. Link to comment Share on other sites More sharing options...
Angela T Posted January 13, 2015 Share Posted January 13, 2015 We still got a ways to go... it's still 34 in DC, 35 in Charlottesville, and 38 in Petersburg right now. I live about 15 minutes due east of Petersburg Va in Prince George and it is 34/22 here currently. Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 Here's the full afternoon briefing slideshow from NWS-RAH http://www.erh.noaa.gov/rah/news/NWSRaleighBriefing13January2015_330PM.pdf +100!!! So many unknowns...not sure how anyone can get disappointed where we stand right now...on the other hand, when it becomes nowcast time and radar doesnt fill in, then jump. Link to comment Share on other sites More sharing options...
PackGrad05 Posted January 13, 2015 Share Posted January 13, 2015 Greg Fishel is not impressed. Said temps may hover at 32 all night long and the roads are warm since we haven't been below freezing since sunday. Link to comment Share on other sites More sharing options...
RevDodd Posted January 13, 2015 Share Posted January 13, 2015 39/32 at FAY ... y'all can let go of that cold air any old time now! Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 Again, shouldn't we be tracking wetbulb rather than strictly looking at temp or dewpoint? Charlottesville wetbulb is 26. TW In theory, yes...but not until precip is around the corner usually. Dewpoint depression-- Determines wet-bulb cooling potential. I have found the (1/3 - 5) rule to work successfully for temperature near freezing. When the dewpoint depression is less than 5, very little cooling takes place when precipitation begins because the air is so close to saturation. The 1/3 -5 rule is as follows: Take the dewpoint depression, subtract 5 from it, divide this number by 3, subtract this number from the temperature. This gives the temperature that will result from evaporational cooling. For example suppose the temperature is 35 and the dewpoint is 18. The dewpoint depression is 35 F - 18 F = 17 , 17 - 5 = 12, 12/3 = 4. This results in evaporational cooling giving a temperature of 35 - 4 = 31 F. Wet-bulb cooling can change rain to freezing rain, sleet or snow. Wet-bulb cooling will move the freezing line into regions that were originally above freezing even the absence of CAA. WAA and wet-bulb cooling will partially or completely offset each other. Link to comment Share on other sites More sharing options...
downeastnc Posted January 13, 2015 Share Posted January 13, 2015 +100!!! So many unknowns...not sure how anyone can get disappointed where we stand right now...on the other hand, when it becomes nowcast time and radar doesnt fill in, then jump. The strength of the cold air is everything, we need it to really overperform and or hang out a bit longer than modeled. I am not sure but I thought someone said earlier it as a bit stronger and deeper in VA than modeled on their latest soundings.... hopefully that translate downstream to NC. Link to comment Share on other sites More sharing options...
LMA1973 Posted January 13, 2015 Share Posted January 13, 2015 You guys "want" an ice storm? Saw Fishel at 5:00-he's really downplaying it. Said it might not even drop below freezing for much of the area. Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 Greg Fishel is not impressed. Said temps may hover at 32 all night long and the roads are warm since we haven't been below freezing since sunday. Last night, WRAL was super confident on temps getting below freezing. Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 It's interesting, but if you've been through enough storms in this area, you see a pattern w/ the people here. The day before everyone get's amped over the HI-RES NAM/WRF combo's (our in house say's so and so)... Then w/in the 12 hours before anything starts the models start converging on something reasonable and everyone's emotions go into the toilet and believe we'll get nothing. It get's tiring after seeing it for the past decade lol. Anyways I think RDU looks good for a solid .2 or so of zr late tonight/tomorrow morning with a dusting of sleet on the grass/roads. Temps will struggle to get above freezing tomorrow w/ the cad/soupy airmass in place and there will not be any WAA due to the SLP being offshore. So freezing drizzle will be an issue tomorrow too. Overall I think it will be a decent system and cause lots of issues tomorrow morning on the roads. Great post right there. Link to comment Share on other sites More sharing options...
mackerel_sky Posted January 13, 2015 Share Posted January 13, 2015 Radar looks anemic at best! Link to comment Share on other sites More sharing options...
superjames1992 Posted January 13, 2015 Share Posted January 13, 2015 Again, shouldn't we be tracking wetbulb rather than strictly looking at temp or dewpoint? Charlottesville wetbulb is 26. TW Not sure we're going to have heavy enough precip to wet bulb. Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 Greg Fishel is not impressed. Said temps may hover at 32 all night long and the roads are warm since we haven't been below freezing since sunday. he busted already this year he needs to sit this one out for a bit.... Link to comment Share on other sites More sharing options...
LMA1973 Posted January 13, 2015 Share Posted January 13, 2015 Still 38 here in Rawlee. I think the mercury is gonna struggle to fall to freezing and we have a nice chilly mist all night. Best case scenario all the way around. Link to comment Share on other sites More sharing options...
BIG FROSTY Posted January 13, 2015 Share Posted January 13, 2015 31.9 and no frizzle right now!!! had drizzle before it dropped to 32 lol Link to comment Share on other sites More sharing options...
SN_Lover Posted January 13, 2015 Share Posted January 13, 2015 36/33 fog is gone and things are drying out. #fail Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 Still 38 here in Rawlee. I think the mercury is gonna struggle to fall to freezing and we have a nice chilly mist all night. Best case scenario all the way around. I think not...temps should hit 31 in Raleigh before midnight quote me on it. Link to comment Share on other sites More sharing options...
Isopycnic Posted January 13, 2015 Share Posted January 13, 2015 35.7f / 31.6f dp 34f wb Cloudy but dry Link to comment Share on other sites More sharing options...
phil882 Posted January 13, 2015 Share Posted January 13, 2015 Yea things definitely aren't looking good for a significant ice accumulation.... the 15 h HRRR forecast suggests most people over most of NC are still < 0.25" by daybreak with most of the Raleigh metro area < 0.10" of liquid precip (totals are provided at ASOS stations and other 1st order stations). Best spots for a glaze appear to be the far NE corner of NC near the VA border. Even here temperatures will be marginal, but totals should be between 0.1 to 0.25" which will allow for more significant ice accretion. http://www.atmos.albany.edu/student/ppapin/lb13_img/hrrr/hrrr_ncep_2d_flt.php Link to comment Share on other sites More sharing options...
Tullioz Posted January 13, 2015 Share Posted January 13, 2015 Not sure we're going to have heavy enough precip to wet bulb. Just had a brief shower pass through Eden and the temperature dropped from 36.7 down to 32.9 in about 15 minutes so it is possible. Just need more in the way of precipitation to make it happen. My current dew point is 30.1 Link to comment Share on other sites More sharing options...
LMA1973 Posted January 13, 2015 Share Posted January 13, 2015 Well one of us probably going to be a degree off I think not...temps should hit 31 in Raleigh before midnight quote me on it. Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 Yea things definitely aren't looking good for a significant ice accumulation.... the 15 h HRRR forecast suggests most people over most of NC are still < 0.25" by daybreak with most of the Raleigh metro area < 0.10" of liquid precip (totals are provided at ASOS stations and other 1st order stations). Best spots for a glaze appear to be the far NE corner of NC near the VA border. Even here temperatures will be marginal, but totals should be between 0.1 to 0.25" which will allow for more significant ice accretion. http://www.atmos.albany.edu/student/ppapin/lb13_img/hrrr/hrrr_ncep_2d_flt.php Hmm...latest HRRR(21z) is wetter than previous, especially in Eastern NC...temps lacking though but the moisture is there. Link to comment Share on other sites More sharing options...
phil882 Posted January 13, 2015 Share Posted January 13, 2015 It's interesting, but if you've been through enough storms in this area, you see a pattern w/ the people here. The day before everyone get's amped over the HI-RES NAM/WRF combo's (our in house say's so and so)... Then w/in the 12 hours before anything starts the models start converging on something reasonable and everyone's emotions go into the toilet and believe we'll get nothing. It get's tiring after seeing it for the past decade lol. Anyways I think RDU looks good for a solid .2 or so of zr late tonight/tomorrow morning with a dusting of sleet on the grass/roads. Temps will struggle to get above freezing tomorrow w/ the cad/soupy airmass in place and there will not be any WAA due to the SLP being offshore. So freezing drizzle will be an issue tomorrow too. Overall I think it will be a decent system and cause lots of issues tomorrow morning on the roads. I agree with this... it won't be a substantial system (in NC) by any means, but thing might be tricky tomorrow morning as temperatures hover near 32 degrees at the surface for a large region with foggy conditions. It will be colder immediately aloft so its possible larger trees may see a glaze that will become noticeable even if temps at 2m are slightly above freezing. Hmm...latest HRRR(21z) is wetter than previous, especially in Eastern NC...temps lacking though but the moisture is there. The 21z HRRR did tick a bit upward with precip totals further east although it stayed relatively steady for the Raleigh/Durham area. And you are exactly right...where there will be significant precip, the temperatures will be even more marginal in NC. The most problematic region is increasingly looking like SE Virginia (which is just on the edge of my maps but show plenty of locations still receiving measurable precip at 1200 UTC with temps < 30F). Those regions might experience more meaningful precip that will make the ice accumulation more problematic. Link to comment Share on other sites More sharing options...
RevDodd Posted January 13, 2015 Share Posted January 13, 2015 FAY is 37/26 at 6 p.m. ... nice little drop there. Link to comment Share on other sites More sharing options...
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