FallsLake

Indices look ok to good today: PNA - Goes strongly positive in the medium range and stays positive in the LR (good/great) AO - Goes neutral and then averages neutral in the LR (but has some wide spread of positive and negative runs (not sure) NAO - Stays neutral in the medium range but then averages negative in the LR (maybe good) https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/teleconnections.shtml

The FV3 GFS is showing some potential at and after News Years. The LR models keep flipping around (more than normal) during that period, which could mean they're having issues seeing the (possible) pattern change.

If all that cold verifies for January (meaning some good blocking), there'll be some suppressed storm tracks.

It seems that when the p-type was snow and it was below freezing (making close to 10:1) it was actually very close. Some of those huge outputs (over 2" in the piedmont) was more tied to the higher QPF that was originally being forecasted.

You live in a good "zone". I remember you did well last year in that early January storm; whereas I got about an inch. Then we both did well in the late January storm. Folks south and east of Raleigh have missed out the last few years. I feel (in my bones) that's going to change this year; a coastal plain blizzard is in order.

It is amazing how that line sets up. I've been really lucky the last few years where I've been just north and west enough to get in on the good snow totals. In past years I've noticed that things even out somewhat with those "eastern storms" -- Fayetteville NE to Rock Mount. With those storms eastern parts of the Triangle do very well. I've seen it snowing hard just east of Wake Forest but nothing at my house. I think we're due for another one of those storms. And as other have said, I would gladly give up snow to see you guys score.

Still very light snow at my location. This should be it. Now the question is how much melting this afternoon. Then how bad will the roads get tonight with the refreeze. I think tomorrow morning may be the worse driving conditions of the event. Folks will see what looks like clear pavement but actually slide on ice. Get ready for lots of reports of wreaks. Edit: sorry I thought I was in the observation thread.

Man after all the snow we're getting this storm is not over (ICE): As this occurs, the forecast low level partial thicknesses in the 1295 to 1305m range indicate more icing can be expected SE of the heavy snow zone in the NW add N Piedmont. That would place areas from portions of Stanly and southern Davidson ENE in an arc through portions of Randolph, northern Moore, Lee, Chatham, Wake, Durham, Franklin, Vance, Granville, and Warren at risk for 0.25+ of icing later this morning into the afternoon. Surface wet bulbs support the area from near Troy and Asheboro to NW of Sanford to near RDU and Henderson in the 32 or below through the event. This will have to be watched closely as Raleigh will be right on the 31-32 line with 33 degrees just 10-20 miles east and south.

HRRR looks good for our area. 2z is out to be 12 and there's plus 6" totals through the Triangle. And it's still snowing.

^^and that's why we see jumps every few hour. As the models change their depictions the values are then pasted on to your respective grids.

Hey I really appreciate it! For others, here's the versions that were released: V1.0 - V2.0 The first version of the NBM was released January 6, 2016 in CONUS AWIPS 16.1.1, after Congress mandated that the NWS develop a blended model approach following Hurricane Sandy in 2012. This first version used 3 models (GFS, GEFS mean, CMCE mean) and covered temperature, wind, and sky cover over the CONUS (Continental United States) region two times a day. Version 2, released November 15, 2016 in CONUS and OCONUS (outside-CONUS) AWIPS 16.2.2, added coverage over Alaska, Hawaii, and Puerto Rico. V3.0 Version 3.0, released July 27th, 2017 (AWIPS 17.3.1) incorporated additional global and mesoscale models for the CONUS, OCONUS, and Oceanic domains along with running hourly and providing 1-36h forecasts. Several new weather elements were added to this version such as calibrated Probability of Precipitation (6-hour) and QPF, ceiling height and visibility, and weather, snow, and ice forecasts to name a few. An exhaustive lists of weather elements added to V3.0 can be found in NWS SCN 17-59. V3.1 NBM V3.1, which is planned to be implemented October 3, 2018 (AWIPS 18.1.1) will continue to incorporate additional global models (i.e.., ECMWF (deterministic and ensemble)) and mesoscale models (i.e., HRRR-Extended (1-36h guidance)) into its suite of model guidance to cover the CONUS, OCONUS, and Oceanic domains. This upgrade will enable the NBM to fill existing product gaps requested by the Aviation, Fire Weather, Water Resources, and Marine NWS Service Program Offices. To date, NBM data has been packaged in GRIB2 and only provided forecasts at gridpoints. NBM V3.1 will introduce a new text product (similar to MOS-station bulletins) that will provide NBM forecasts at stations. The data in these bulletins are the NBM’s nearest grid point forecast to the corresponding station. We will be generating four individual NBM text bulletin products every hour, each covering different forecast horizons. For a complete discussion concerning these messages along with an exhaustive listing weather elements that will be added to NBM V3.1 and their dissemination times please see the following NBM V3.1 SCN.

Earlier today my NWS grid forecast was set at 5-9" for Sunday (daytime period). It was reduced to 3-5" after lunch time. Now it's been bumped back up to 3-7". Again, I'm wondering what models they're using to create these output. Anybody know?

Looking at the 12z GFS. The crazy/fantasy snow map has >10" in Wake County before the change over occurs. Even if that's half that value, we could still see some nice (actual 5-10) amounts through out the county.

Man I don't know. Does anybody know what model the NWS uses for their grid output? You can tell they're using one with the two hour flips between p-types.

They cut it down across the board. Sunday I was at 5-9" and now its 3-5. Then Sunday night have now have 1-2" of sleet. Edit: this might be because of reduced qpf

Very well could be; and with past events (and being marginal with upper and surface temps) we should expect this outcome. Like I stated in an earlier post, if it ends up being primarily sleet it would be impressive to see all the forecasted qpf. Liquid to sleet would be ~4". I would call that a win. Plus amazing sledding for the kids....

So for RDU folks, the 12z NAM did come in slightly colder. Meaning the initial snow line setups just south and east of Wake County. Then it still slowly pushes NW through the event. The last run had it eventually turning to rain back into Durham/Orange counties. But this run keeps the rain line no farther NW then the RDU airport until very late in the game; when the bulk of the precip is over.

At hr 22 it looks better for the RDU folks. Snow line is setting up just south of Wake county; whereas is was well into Wake at the same time on 6z. So colder. Edit 12z NAM

Looking at my grid forecast, they're giving me 7-13". I'll still call this a win with 5" with a little sleet and freezing rain. That initial snow is going to be everything. As others have stated once you get snow and if it's heavy, it many times overcomes slightly above freezing mid level temps to stay all snow.

I've seen some impressive sleet storms. But if you're going to get as much qpf as forecasted, you either want all sleet or all snow.

yeah, six inches of snow with some sleet and then 1/4 of ice would look nice.

I agree, 31 or 32 degrees with moderate freezing rain will have at least half of that run off before it can freeze. I'll be real interested in the dew point to our north once the event evolves. Also as we get the initial snow, that can pull our temps down lower. If we happen to get into the upper 20s when we transition, the ice could be worse.

This would be a fun storm for RDU. 6" of snow and 1" of ice.

Rough time and it was doubly rough for you having a new born. Glad everything worked out; definitely a good weather story to link to her birth.

That looks reasonable. I was here for that 2002 storm and it was horrible. We lost a car from a pine tree breaking in half, all of our fence line, and my wife watched as a tree was pulled over from its root ball because of the ice weight. **I like (a little) ice on the trees, but to an extent.