Inudaw Posted February 19, 2020 Share Posted February 19, 2020 18z nam as whole brought higher amounts to Richmond, but was more brutal with the northern cut off north of Richmond. Link to comment Share on other sites More sharing options...
RVASnowLover Posted February 19, 2020 Share Posted February 19, 2020 Sharp cut off north of Richmond which is typical to see a sharp cut off for the area. Link to comment Share on other sites More sharing options...
Hyphnx Posted February 19, 2020 Share Posted February 19, 2020 Maybe living in Chester will finally pay off... 1 Link to comment Share on other sites More sharing options...
cyclogenesis Posted February 19, 2020 Share Posted February 19, 2020 February 19, 2020 ►► NEW Update! ◄◄ -- ECM has updated its snowfall for Richmond to now include 1" to 1 1/2" of snowfall. It now lies between the extremities of the 0.1" Gfs & the 4-5" Nam. -- cyclogenesis Link to comment Share on other sites More sharing options...
cyclogenesis Posted February 19, 2020 Share Posted February 19, 2020 It's ranging anywhere between 0.8" to 1.5" in the Greater Richmond, VA region. Link to comment Share on other sites More sharing options...
RVASnowLover Posted February 19, 2020 Share Posted February 19, 2020 No changes in the 18z GFS. Still pretty dry/light. Link to comment Share on other sites More sharing options...
cyclogenesis Posted February 19, 2020 Share Posted February 19, 2020 Forecast surface low positioning at 10 PM, Thursday night, 2/20/2020. These are the visuals on the comparative differences between the few models' depictions on the surface low's positioning at 10 PM on Thursday night. The Gfs & ECM are both identical in placement at 10 PM, but moisture is more generous on ECM's side. -- cyclogenesis. Link to comment Share on other sites More sharing options...
wasnow215 Posted February 19, 2020 Share Posted February 19, 2020 7 hours ago, RVASnowLover said: Considering how awful this winter has been, I will take 1-3" and run with it. He’s a troll man. Link to comment Share on other sites More sharing options...
wasnow215 Posted February 19, 2020 Share Posted February 19, 2020 1-3” for RVA. least NW areas. Most SE areas. Possible 4” snow lolli. Link to comment Share on other sites More sharing options...
cyclogenesis Posted February 19, 2020 Share Posted February 19, 2020 So, with continuing 6 hour & 12 hour updates, here's how the calculator works out again with the forecasting models for tomorrow on Thursday, Feb. 20. For Richmond, VA: 00Z, 12Z ECMWF -->> 0.3" & 1.2" for Richmond 12Z, 18Z CMC -->> 0.6" & 1.7" for Richmond 12Z, 18Z Gfs -->> 0.1" & 0.7" (ya, it rose to 0.7" on its 18Z output) 12Z Wrf -->> Trace 18Z HRRR -->> Trace Averaging these 8 totals yields -->> ~ 0.6" of snowfall for Richmond, bounded in that period between 2 PM and 10 PM, Thursday afternoon & night. In the past, the ??? marks typically hinge upon "will it be cold enough for snow?" That's not the question this time. It WILL be cold enough for snow in Richmond. The question is the EXTENT of the moisture & amount of dynamical forcing. The thermodynamic structure on forecast Skew-T soundings is GOOD enough for snow. The blue Skew-T is Nam's depiction at 4 PM on Thursday; entire sounding below 0°C. The pink Skew-T is Gfs' depiction at 4 PM on Thursday. entire sounding ABOVE 1000 mb is below 0°C The difference in thermal structure is that Gfs is ABOVE freezing, from ground level to 1000 mb, which is approximately 800 ft at 4PM. This is okay. The snow checklist says as long as the freezing level is LESS than 1,200 ft high, then it still has capability to fall as snow. The probability for snow tomorrow is HIGH in Richmond. Better than 50%. I'd place it at 70% chance, (AFTERNOON & NIGHT). Pending tonight's 00Z output, I'd say the overall AVERAGE snowfall totaling scheme for Richmond has RISEN to AROUND 1/2" TO 3/4". 1/2" to 3/4" of snowfall will cover all vehicles, and will also cover grassy areas, too. You'll still be able to see blades of taller, thicker grass, but it will be noticeably covered. ►► TRENDS, FOR RICHMOND, VIRGINIA ◄◄ The changes, since last night, for Richmond?? The snowfall amounts. Most notably, the ECMWF rising from 0 snowfall from 2 iterations ago, (yesterday morning), UP to: 0.3" from last night's iteration, UP to: 1.2" of snowfall on the current 12Z iteration, from this morning, (2/19), for Richmond. Gfs had previously shown consistency in 0.1" to 0.2" on its previous iterations, but NOW has surged up to 0.7" of snowfall. CMC's Gem has also risen from 0.6" to 1.7" between the 12Z & 18Z output. Nam continues between 4"-5" on its past 3 cycles. The new-age, HI resolution models are unchanged thus far showing only an unmeasurable, TRACE. While these new-age models of H-Rap & Wrf performed stellar in the predictions of the Dec. 2018 snowfall in Richmond, they did very poorly last November 2019, with the last memorable event, in that they again showed NO measureable snowfall. So pouring through the changes brings UP the snowfall for Richmond to between 1/2" to 1". This is plenty enough snow to see a wintery landscape. -- cyclogenesis Link to comment Share on other sites More sharing options...
eaglesin2011 Posted February 19, 2020 Share Posted February 19, 2020 Nice write up for 1/2 inch to inch ha Link to comment Share on other sites More sharing options...
arlwx Posted February 20, 2020 Share Posted February 20, 2020 WSWs up for SE Va. URGENT - WINTER WEATHER MESSAGE National Weather Service Wakefield VA 336 AM EST Thu Feb 20 2020 NCZ012>016-030>032-VAZ096-097-201645- /O.UPG.KAKQ.WS.A.0001.200220T2000Z-200221T1200Z/ /O.NEW.KAKQ.WS.W.0001.200220T2000Z-200221T1200Z/ Northampton-Hertford-Gates-Pasquotank-Camden-Bertie-Chowan- Perquimans-Suffolk-Chesapeake- Including the cities of Margarettsville, Ahoskie, Corapeake, Elizabeth City, Horseshoe, Lilly, Sharon, Quitsna, Edenhouse, Merry Hill, Midway, Windsor, Cape Colony, Edenton, Hancock, Macedonia, Mavaton, Saint Johns, Valhalla, Jacocks, Woodville, Chuckatuck, Cleopus, Crittenden, Deanes, Downtown Suffolk, Driver, Elwood, Mount Pleasant, Bowers Hill, Chesapeake Airport, Deep Creek, Fentress, Great Bridge, and Greenbrier 336 AM EST Thu Feb 20 2020 ...WINTER STORM WARNING IN EFFECT FROM 3 PM THIS AFTERNOON TO 7 AM EST FRIDAY... * WHAT...Mixed rain and snow, changing to snow. Snow may be heavy at times tonight. Total snow accumulations of 3 to 6 inches. Locally higher amounts are possible. Wind gusst up to 30 mph. * WHERE...Portions of southeast Virginia and northeast North Carolina. * WHEN...From 3 PM this afternoon to 7 AM EST Friday. URGENT - WINTER WEATHER MESSAGE National Weather Service Wakefield VA 336 AM EST Thu Feb 20 2020 NCZ017-VAZ087>090-092-093-095-098-523>525-201645- /O.UPG.KAKQ.WS.A.0001.200220T2000Z-200221T1200Z/ /O.NEW.KAKQ.WS.W.0001.200220T2000Z-200221T1200Z/ Western Currituck-Greensville-Sussex-Surry-James City-Southampton- Isle of Wight-Norfolk/Portsmouth-Virginia Beach-York-Newport News- Hampton/Poquoson- Including the cities of Knotts Island, Emporia, Wakefield, Barham, Gwaltney Corner, Bacons Castle, Chippokes State Park, Hog Island Game Reserve, Poolesville, Booth Fork, Williamsburg, Franklin, Carrsville, Lees Mill, Benns Church, Bethel Church, Carrollton, Lawson, Longview, Downtown Norfolk, Ghent, Norfolk International Arpt, Norfolk NAS, Norview, Ocean View, Wards Corner, Back Bay, Bayside, Cape Henry, Dam Neck, Gallups Corner, Kempsville, London Bridge, Grafton, Tabb, Beaconsdale, Denbigh, Fort Eustis, Hilton Village, Lee Hall, Menchville, Newport News, Buckroe Beach, Fort Monroe, Fox Hill, Grand View, Hallwood, Hampton, and Langley AFB 336 AM EST Thu Feb 20 2020 ...WINTER STORM WARNING IN EFFECT FROM 3 PM THIS AFTERNOON TO 7 AM EST FRIDAY... * WHAT...Mixed rain and snow, changing to all snow. Snow may be moderate to heavy at times this evening. Total snow accumulations of 2 to 4 inches. Winds gusting as high as 40 mph. * WHERE...Portions of southeast Virginia and northeast North Carolina. * WHEN...From 3 PM this afternoon to 7 AM EST Friday. 1 Link to comment Share on other sites More sharing options...
RichmondTarHeel Posted February 20, 2020 Share Posted February 20, 2020 Not a fan of the 06z NAMs. Struggles to get any accumulation North and west of basically Petersburg. Link to comment Share on other sites More sharing options...
SoCoWx Posted February 20, 2020 Share Posted February 20, 2020 2 minutes ago, NovaTarHeel said: Not a fan of the 06z NAMs. Struggles to get any accumulation North and west of basically Petersburg. Noticed that. Gotta say, with how this winter has gone, not really surprised that Richmond may entirely miss out while places to our South get snow. I haven’t lived here but 5 years, but in those 5 years, this has been the most lackluster, most disappointing winter so far. Time to cut our losses IMO. Link to comment Share on other sites More sharing options...
eaglesin2011 Posted February 20, 2020 Share Posted February 20, 2020 I dont think there is any way that RIC (city) misses this.. I think 1-3 is a good call.. maybe 2-4 if lucky with a good band Link to comment Share on other sites More sharing options...
RVASnowLover Posted February 20, 2020 Share Posted February 20, 2020 22 minutes ago, eaglesin2011 said: I dont think there is any way that RIC (city) misses this.. I think 1-3 is a good call.. maybe 2-4 if lucky with a good band Hope you're right. NAM and 12z HRRR show nothing for RVA. RGEM get an inch or two in RVA Link to comment Share on other sites More sharing options...
RichmondTarHeel Posted February 20, 2020 Share Posted February 20, 2020 12z NAM suite completely blanks the Richmond area. Link to comment Share on other sites More sharing options...
Hyphnx Posted February 20, 2020 Share Posted February 20, 2020 It's been real! Maybe next year? Link to comment Share on other sites More sharing options...
RVASnowLover Posted February 20, 2020 Share Posted February 20, 2020 7 minutes ago, NovaTarHeel said: 12z NAM suite completely blanks the Richmond area. Even Petersburg area only gets maybe a dusting to half inch. I'm checking out. Maybe we'll get surprised. Link to comment Share on other sites More sharing options...
eaglesin2011 Posted February 20, 2020 Share Posted February 20, 2020 F the models at this point .... It's radar & water vapor hallucination time! May need a few real drinks later ha Link to comment Share on other sites More sharing options...
RichmondTarHeel Posted February 20, 2020 Share Posted February 20, 2020 16 minutes ago, eaglesin2011 said: F the models at this point .... It's radar & water vapor hallucination time! May need a few real drinks later ha Yeah, I'm not giving up yet. Radar looks better than the NAM already. Lots of times the precip shield extends much further than the models show. At the very least, we should see some flurries, which will make this the 2nd best storm of the year! Link to comment Share on other sites More sharing options...
RVASnowLover Posted February 20, 2020 Share Posted February 20, 2020 Just now, NovaTarHeel said: Yeah, I'm not giving up yet. Radar looks better than the NAM already. Lots of times the precip shield extends much further than the models show. At the very least, we should see some flurries, which will make this the 2nd best storm of the year! That's a sad true statement. Link to comment Share on other sites More sharing options...
eaglesin2011 Posted February 20, 2020 Share Posted February 20, 2020 Lynchburg VA is already reporting rain from some overrunning precip.. so guess we will see Link to comment Share on other sites More sharing options...
RVASnowLover Posted February 20, 2020 Share Posted February 20, 2020 39 minutes ago, eaglesin2011 said: F the models at this point .... It's radar & water vapor hallucination time! May need a few real drinks later ha I've already started with the radar hallucinations lol. Radar looks pretty decent. Link to comment Share on other sites More sharing options...
eaglesin2011 Posted February 20, 2020 Share Posted February 20, 2020 Yeah Its def hitting a brick wall if you look back of the storm in Nashville TN area and everything drifting south... to me the boarder or VA/NC somewhere around roanke rapids nc looks to be the sweet spot .. Storm def looks to moving quickly ... looks to be a little front running band headed to chester area is that producing anything? Link to comment Share on other sites More sharing options...
Hyphnx Posted February 20, 2020 Share Posted February 20, 2020 23 minutes ago, eaglesin2011 said: Yeah Its def hitting a brick wall if you look back of the storm in Nashville TN area and everything drifting south... to me the boarder or VA/NC somewhere around roanke rapids nc looks to be the sweet spot .. Storm def looks to moving quickly ... looks to be a little front running band headed to chester area is that producing anything? It is, working on getting live feed and pictures now. Link to comment Share on other sites More sharing options...
RVASnowLover Posted February 20, 2020 Share Posted February 20, 2020 It's going to be awfully close in RVA. Link to comment Share on other sites More sharing options...
eaglesin2011 Posted February 20, 2020 Share Posted February 20, 2020 "CLOSE" Being the key word Either this or this Link to comment Share on other sites More sharing options...
cyclogenesis Posted February 20, 2020 Share Posted February 20, 2020 Feb. 20, 2020 1100 AM A lot of what you're seeing on radar at this moment, at 11 AM, is Virga, for which the radar beam is hitting between altitudes of 6K to 10K ft, from Prince Edward County & Westward. But this Virga is needed in order to commence the process of saturating the tropospheric column from the TOP, downward through the lower layers. An inspection of GFS' 12Z Skew-T forecast sounding for 11 AM and 1 PM today shows a very DRY layer, below 10,000 ft at 11 AM, and below 9,000 ft at 1 PM. As the course of the late afternoon progresses, this dry layer DEPTH of 9,000 to 10,000 ft and below, will diminish GREATLY in depth, and by 4 PM this afternoon, over Richmond, that layer between 10,000 ft & 3,500 ft becomes nearly saturated, so that all that is left of the dry layer is below 3,500 ft, by 4 PM. Both models agree on this assessment. As I say, this Virga is needed to bring DOWN those temperatures by evaporative cooling, closer to the dewpoints, at those drier levels, while at the same time, the dewpoints surge way UPWARD, in order to help saturate the column of air aloft. For without this saturating of the column, there would be no snow event. I expect that by 7 PM this evening, the last remaining dry layer will only exist from the 950 mb level, (2,100 ft), and below. The thinking is that this last little bit of shrinking dry layer depth, confined to the lowest 2,000 ft, to the ground, should be a thin enough dry layer depth for at least a little bit of snow to survive in falling to the ground, before evaporating as virga, for which is happening at current moment in the 9,000 ft. dry layer depth at 11 AM. So, bottom line is there's a dry layer between ground and 8,000 ft here at 11 AM, (an 8,000 ft dry-layer depth at 11 AM over Richmond). Then, by 7 PM the dry-layer depth only becomes 2,100 ft thick, from ground to 2,100 ft. What's encouraging to me, is that look at RIC's cloud height layer at 11 AM. It shows OVC080. So, this BEATS models expectations that the dry layer which was advertised to be 10,000 ft in depth at 11 AM, is now already only 8,000 ft in depth, because of the observation at 11 AM, showing overcast deck of clouds at 8,000 ft on the 11 AM observation. The shrinking of that dry depth layer is AHEAD of schedule by being 2,000 ft LESS in depth, 8,000 ft, vs. the 10,000 ft depth that was advertised for 11 AM, by both models. It will be interesting to see at WHAT DEPTH the dry layer needs to shrink & diminish to, in order for snowflakes to survive making it all the way down to the ground level, without evaporating. -- cyclogenesis Link to comment Share on other sites More sharing options...
eaglesin2011 Posted February 20, 2020 Share Posted February 20, 2020 ha ha I know its most likely Virga but a decent band was forming that's why I asked if anything was hitting the ground.... If we dont have anything by 7pm I dont expect us to get anything measurable . This system is moving quickly Link to comment Share on other sites More sharing options...
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