superjames1992 Posted January 13, 2015 Share Posted January 13, 2015 Wow, radar is rockin', CR! Link to comment Share on other sites More sharing options...
packfan98 Posted January 13, 2015 Author Share Posted January 13, 2015 Wow, radar is rockin', CR! Woohoo! It's NOWCAST TIME! Link to comment Share on other sites More sharing options...
Amos83 Posted January 13, 2015 Share Posted January 13, 2015 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. Well I was more curious if they considered it at all. Not that I'm thinking it will matter much but I'd think heavy drizzle would accumulate pretty good on limbs and such. Again, not that I'm thinking it would matter much. Link to comment Share on other sites More sharing options...
FallsLake Posted January 13, 2015 Share Posted January 13, 2015 NWS just dropped my ice accrual to less than .1 for the overnight (did not state amounts for tomorrow). But they had just up dated the winter storm watch at noon to restate higher amounts. Link to comment Share on other sites More sharing options...
griteater Posted January 13, 2015 Share Posted January 13, 2015 1PM actual Wet Bulb temp at RDU (Raleigh) is 34.8 12z Model Forecast Wet Bulb for 1PM at RDU NAM - 36.9 GFS - 34.4 By deduction (lol) we can say that the GFS has a better handle on surface temps. GFS has RDU with temp of 32, dewpoint of 29 at 7PM tonight. Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 1PM actual Wet Bulb temp at RDU (Raleigh) is 34.8 12z Model Forecast Wet Bulb for 1PM at RDU NAM - 36.9 GFS - 34.4 By deduction (lol) we can say that the GFS has a better handle on surface temps. GFS has RDU with temp of 32, dewpoint of 29 at 7PM tonight. They're going to have to hussle up and get down. Looking upstream, temps are in the upper 30s into VA. Link to comment Share on other sites More sharing options...
Brick Tamland Posted January 13, 2015 Share Posted January 13, 2015 Link to comment Share on other sites More sharing options...
Brick Tamland Posted January 13, 2015 Share Posted January 13, 2015 NWS just dropped my ice accrual to less than .1 for the overnight (did not state amounts for tomorrow). But they had just up dated the winter storm watch at noon to restate higher amounts. They seem to be going very conservative. Link to comment Share on other sites More sharing options...
jburns Posted January 13, 2015 Share Posted January 13, 2015 Well I was more curious if they considered it at all. Not that I'm thinking it will matter much but I'd think heavy drizzle would accumulate pretty good on limbs and such. Again, not that I'm thinking it would matter much.Ah, ok. Your question was about considering drizzle in QPF total. As for accumulations of ice, all things being equal a higher percentage of drizzle will freeze compared to a heavier rain. Of course there less liquid to begin with. It comes down to what it usually comes down to around here. You just have to wait and see how it plays out. Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 They seem to be going very conservative. Usually justified. Link to comment Share on other sites More sharing options...
Poimen Posted January 13, 2015 Share Posted January 13, 2015 I'm not concerned so much with the cold as I am the precip. I fear precip west of 95 ends up spotty and light without much in the way of significant accrual. Time will tell, as always. Link to comment Share on other sites More sharing options...
thunderwolf 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. Ok, it was my understanding that was one of the weakness of the models, thanks for clearing that up. At any rate, models generally don't handle CAD scenarios well. One of the reasons is that they underestimate the surface layer cold dry air that ends up creating the huge inversion and locking the CAD in place. So I would lean to more drier air filtering in and reducing icing totals. On the other hand, this would lead to colder temperatures and a greater percentage of the rain freezing. Tough call. Link to comment Share on other sites More sharing options...
FallsLake Posted January 13, 2015 Share Posted January 13, 2015 RAH update a few minutes ago(little bit of a bummer -- means no winter Storm Warnings for anybody): NATIONAL WEATHER SERVICE RALEIGH NC121 PM EST TUE JAN 13 2015.SYNOPSIS...BLUSTERY NORTHERLY WINDS WILL USHER COLDER AIR INTOCENTRAL NC TODAY. A SERIES OF UPPER LEVEL DISTURBANCES WILLMAINTAIN AN UNSETTLED WEATHER PATTERN OVER THE CAROLINAS THROUGHTHURSDAY. HIGH PRESSURE WILL BUILD INTO THE AREA FOR THE WEEKEND.&&.NEAR TERM /THROUGH WEDNESDAY/...AS OF 1130 AM TUESDAY...STRONG HIGH PRESSURE WILL BUILD ACROSS THE GREAT LAKES AND INTO THENORTHEAST AND EXTEND INTO OUR REGION TODAY TRANSPORTING A COLDER ANDDRIER AIR MASS. TEMPERATURES HAVE ALREADY REACHED THEIR ZENITHACROSS CENTRAL NC AND WILL FALL VERY SLOWLY BUT REMAIN ABOVEFREEZING THROUGH THE LATE AFTERNOON HOURS. A NARROW REGION OFISENTROPIC UPGLIDE ATOP THE DEEPENING SURFACE BASED COLD LAYER ALONGWITH A WEAK DISTURBANCE ALOFT IS PRODUCING A FEW RAIN SHOWERS WITHVERY LIMITED COVERAGE. WITH THE COLD AIR DAMMING IN PLACE...SPOTTYDRIZZLE IS BEING REPORTED AS EXPECTED. HAVE ADJUSTED HOURLYTEMPERATURE AND DEWPOINT FIELDS GIVEN RECENT OBSERVATIONS USING ABLEND OF RECENT HRRR RUNS. HAVE ALSO INCREASED WIND GUSTS SLIGHTLYAS THE HIGH SURGES INTO HE AREA. POPS FOR TODAY WILL RANGE FROM LOWCHANCE VALUES ACROSS THE SOUTH AND SOUTHEAST TO SLIGHT CHANCE NEARTHE VIRGINIA BORDER. -BLAESUPDATE FOR TONIGHTS STORM...THE LATEST MODEL GUIDANCE HAS TRENDEDSLIGHTLY WARMER WITH TEMPERATURES ACROS THE SANDHILLS AND SOUTHERNCOASTAL PLAIN. SREF ENSEMBLE GUIDANCE SUGGESTS THAT SUB-FREEZINGTEMPERATURES WONT ARRIVE TIL A FEW HOURS AFTER MIDNIGHT IN THOSELOCATIONS WHICH WILL LIMIT THE OVERALL FREEZING RAIN ACCUMULATIONTOTALS. STILL EXPECT A SWEET SPOT WITH HIGHER AMOUNTS FURTHER NORTH...MOST LIKELY RANGING BETWEEN 0.10 TO AS MUCH AS 0.20 INCHES IN AREGION STRETCHING FROM SANFORD TO NEAR AND EAST OF RALEIGH TONASHVILLE. MORE DETAILS TO FOLLOW IN THE AFTERNOON FORECASTDISCUSSION. -BLAES Link to comment Share on other sites More sharing options...
Amos83 Posted January 13, 2015 Share Posted January 13, 2015 Ah, ok. Your question was about considering drizzle in QPF total. As for accumulations of ice, all things being equal a higher percentage of drizzle will freeze compared to a heavier rain. Of course there less liquid to begin with. It comes down to what it usually comes down to around here. You just have to wait and see how it plays out. Yeah my bad, poorly written question on my part. Thanks for the reply... no more cluttering up of the thread Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 RAH update a few minutes ago(little bit of a bummer -- means no winter Storm Warnings for anybody): NATIONAL WEATHER SERVICE RALEIGH NC 121 PM EST TUE JAN 13 2015 .SYNOPSIS...BLUSTERY NORTHERLY WINDS WILL USHER COLDER AIR INTO CENTRAL NC TODAY. A SERIES OF UPPER LEVEL DISTURBANCES WILL MAINTAIN AN UNSETTLED WEATHER PATTERN OVER THE CAROLINAS THROUGH THURSDAY. HIGH PRESSURE WILL BUILD INTO THE AREA FOR THE WEEKEND. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 1130 AM TUESDAY... STRONG HIGH PRESSURE WILL BUILD ACROSS THE GREAT LAKES AND INTO THE NORTHEAST AND EXTEND INTO OUR REGION TODAY TRANSPORTING A COLDER AND DRIER AIR MASS. TEMPERATURES HAVE ALREADY REACHED THEIR ZENITH ACROSS CENTRAL NC AND WILL FALL VERY SLOWLY BUT REMAIN ABOVE FREEZING THROUGH THE LATE AFTERNOON HOURS. A NARROW REGION OF ISENTROPIC UPGLIDE ATOP THE DEEPENING SURFACE BASED COLD LAYER ALONG WITH A WEAK DISTURBANCE ALOFT IS PRODUCING A FEW RAIN SHOWERS WITH VERY LIMITED COVERAGE. WITH THE COLD AIR DAMMING IN PLACE...SPOTTY DRIZZLE IS BEING REPORTED AS EXPECTED. HAVE ADJUSTED HOURLY TEMPERATURE AND DEWPOINT FIELDS GIVEN RECENT OBSERVATIONS USING A BLEND OF RECENT HRRR RUNS. HAVE ALSO INCREASED WIND GUSTS SLIGHTLY AS THE HIGH SURGES INTO HE AREA. POPS FOR TODAY WILL RANGE FROM LOW CHANCE VALUES ACROSS THE SOUTH AND SOUTHEAST TO SLIGHT CHANCE NEAR THE VIRGINIA BORDER. -BLAES UPDATE FOR TONIGHTS STORM...THE LATEST MODEL GUIDANCE HAS TRENDED SLIGHTLY WARMER WITH TEMPERATURES ACROS THE SANDHILLS AND SOUTHERN COASTAL PLAIN. SREF ENSEMBLE GUIDANCE SUGGESTS THAT SUB-FREEZING TEMPERATURES WONT ARRIVE TIL A FEW HOURS AFTER MIDNIGHT IN THOSE LOCATIONS WHICH WILL LIMIT THE OVERALL FREEZING RAIN ACCUMULATION TOTALS. STILL EXPECT A SWEET SPOT WITH HIGHER AMOUNTS FURTHER NORTH ...MOST LIKELY RANGING BETWEEN 0.10 TO AS MUCH AS 0.20 INCHES IN A REGION STRETCHING FROM SANFORD TO NEAR AND EAST OF RALEIGH TO NASHVILLE. MORE DETAILS TO FOLLOW IN THE AFTERNOON FORECAST DISCUSSION. -BLAES That was issued earlier today...a couple hours ago. I do agree with the concern...the juxtaposition of cold/highest precip may not be ideal. It would be nice to start to see the Rap and HRRR trend wetter, but I don't believe we're seeing that. Link to comment Share on other sites More sharing options...
ILMRoss Posted January 13, 2015 Share Posted January 13, 2015 Raleigh will probably issue WSWarnings with the afternoon package around 3. I'm willing to bet wake is WWA Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 RAH update a few minutes ago(little bit of a bummer -- means no winter Storm Warnings for anybody): He mentions up to 0.20...that's only 0.05 away from warning criteria....it's still in the game IMO for the already issued Watch area. Link to comment Share on other sites More sharing options...
griteater 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? In a sense we are all newbs in that no one has all the right answers. For the SREF, I'd say the best way to view it is to take the SREF mean and use it as part of a multi-model consensus as opposed to solely using the SREF members or SREF Mean. The GFS and Euro are both drier than the SREF mean for RDU. Link to comment Share on other sites More sharing options...
FallsLake Posted January 13, 2015 Share Posted January 13, 2015 That was issued earlier today...a couple hours ago. I do agree with the concern...the juxtaposition of cold/highest precip may not be ideal. It would be nice to start to see the Rap and HRRR trend wetter, but I don't believe we're seeing that. Here's the latest HRRR at hour 14(as far as I have) -- shows freezing rain from about your location north and west. If seems to lock on to this zone/area and doesn't move it much more east. http://mag.ncep.noaa.gov/Image.php?fhr=01400ℑ=data%2Fhrrr%2F17%2Fhrrr_east-us_01400_precip_type.gif&model=hrrr&area=east-us¶m=precip_type&group=Model+Guidance&preselected_formatted_cycle_date=20150113+17+UTC&imageSize=M&ps=area&use_mins=yes Link to comment Share on other sites More sharing options...
Cold Rain Posted January 13, 2015 Share Posted January 13, 2015 Here's the latest HRRR at hour 14(as far as I have) -- shows freezing rain from about your location north and west. If seems to lock on to this zone/area and doesn't move it much more east. http://mag.ncep.noaa.gov/Image.php?fhr=01400ℑ=data%2Fhrrr%2F17%2Fhrrr_east-us_01400_precip_type.gif&model=hrrr&area=east-us¶m=precip_type&group=Model+Guidance&preselected_formatted_cycle_date=20150113+17+UTC&imageSize=M&ps=area&use_mins=yes Yeah, it kinda stays put. Hard to tell how much actually falls. Link to comment Share on other sites More sharing options...
FallsLake Posted January 13, 2015 Share Posted January 13, 2015 Dew point is 30 at RDU (actually hit this at 1) Link to comment Share on other sites More sharing options...
PackGrad05 Posted January 13, 2015 Share Posted January 13, 2015 Things have been awfully quiet the past couple hours... I guess we are just waiting on new model runs and/or NWS new statement. Link to comment Share on other sites More sharing options...
FallsLake Posted January 13, 2015 Share Posted January 13, 2015 Dew point is 19 at Richmond. Precip building in SC and pushing NE. The race is on... Link to comment Share on other sites More sharing options...
phil882 Posted January 13, 2015 Share Posted January 13, 2015 Latest HRRR sounding guidance suggests that RDU doesn't go below freezing until 04 UTC (11pm). Looks like a pretty significant warm nose above that. Another important point is the shallow nature of the moisture, which doesn't extend much above the warm nose. As the cold nose gets deeper that will probably mean a transition from freezing rain to a sleet/freezing rain mix as the event progresses into its later stages. http://www.atmos.albany.edu/student/ppapin/lb13_img/hrrr/hrrr_ncep_snd_rdu.php P.S. For those who are interested and since this event is more likely to impact central NC rather than areas further south and east, I've shifted the floater HRRR grid to be centered over Greensboro, NC for the latest model cycle (and will leave it there until further notice). http://www.atmos.albany.edu/student/ppapin/hrrr.php#flt (images should be loading in real time... and it takes about 15 minutes to populate the images in full). This looper is nice because it also allows for enhanced mobile functionality (swipe left/right up/down to cycle through images). Questions and comments appreciated since this is still a work in progress! Link to comment Share on other sites More sharing options...
PackGrad05 Posted January 13, 2015 Share Posted January 13, 2015 Those sounds look to go below freezing by 10-11... marginally at least Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 Latest HRRR sounding guidance suggests that RDU doesn't go below freezing until 04 UTC (midnight). Looks like a pretty significant warm nose above that. Another important point is the shallow nature of the moisture, which doesn't extend much above the warm nose. As the cold nose gets deeper that will probably mean a transition from freezing rain to a sleet/freezing rain mix as the event progresses into its later stages. http://www.atmos.albany.edu/student/ppapin/lb13_img/hrrr/hrrr_ncep_snd_rdu.php 04 UTC is 11pm I thought? EST? Link to comment Share on other sites More sharing options...
phil882 Posted January 13, 2015 Share Posted January 13, 2015 04 UTC is 11pm I thought? EST? Haha yes my mistake! Apparently my brain is still on vacation Link to comment Share on other sites More sharing options...
jburns Posted January 13, 2015 Share Posted January 13, 2015 Those sounds look to go below freezing by 10-11... marginally at least I think we are headed for another dreaded, freezing on elevated surfaces event. 30-31º just won't get it done at ground level. There is more latent heat in the ground than you think, even after the recent quick cold snap. Of course, given enough precip at a slow enough rate, you can still have a significant event with ice build up on trees. Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 the arw for RDU, FWIW, temps look fine for majority of precip. Link to comment Share on other sites More sharing options...
Jon Posted January 13, 2015 Share Posted January 13, 2015 NWS forecast images issued 2pm Temps @10pm Ptype @10pm...-RN/-ZR at 9 to -ZR changeover by 10 Link to comment Share on other sites More sharing options...
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