The FIRST CALL snow forecast map is not significantly different from the first guess but there are some changes The 4 INCH snow line is now pushed north of DC and Baltimore… and a 6-inch snow line is now pushed north of Richmond but still south of Ashland. There also appears to be a pocket of 6 inch snowfall in interior portions of Southwest Virginia. The 4 inch snow line is pushed up towards Winchester and covers most of the northern Shenandoah Valley.
The morning and midday data has not changed significantly. The north trend has stopped. There is a very sharp cut-off to the north edge of the shield as is usually the case when you have Coastal storms which are moving in a ENE direction away from the North Carolina coast. With this sort of storm track… you can only get the precipitation so far inland before the energy and the lifting mechanism which is what produces the precipitation comes to an end.
Now that we are within the approach of the event ….we can take a look at the short-range models and see if they match or make sense with some of the global models which are forecasting huge amounts of snow. As I am sure you have seen and heard by now the operational GFS model continues to show huge amounts of snow of 8–13” across large portions of Virginia and Southern Maryland into the Delmarva. Even the European model during the early Sunday morning model run showed a large area of 8 to 14 across Central Virginia into Southern Maryland and the Delmarva. QUESTION…is that possible? Is that likely?
THIS IS FOOKIGN LAUGHABLE on the GFS and the EURO
So we have to compare what the short-range models are showing with the Big snow model forecast from the various Global models. In other words we are checking to see if it makes sense.
When you shift from the global models over to the short-range models you have to look at the nuances of what the data is showing. We do this by taking a look at things such as
- the starting time
- the ending time
- the amount of precipitation
- the surface temperatures
- the intensity of the precipitation
- and the mid-level temperatures of the atmosphere
to see if there is any possibility that somebody in Virginia or Southern Maryland or the Delmarva is going to see 10 or 12 inches of snow.
When we do that.. we find that there is little chance that any location in Virginia southern Maryland or the Delmarva will see 10+ inches of snow.
In addition to the wet and warm grounds.. most of the short-range data show that this is going to be a six or seven our event. It starts in Washington DC around 2 a.m. on Monday and it ends by 1 or 2 p.m. in the afternoon. That is essentially a 10 or 11 hour event and during that event a lot of the snow is going to melt on contact until the temperature start to crash on midday Monday and drop below 30 degrees.
in Central Virginia Richmond the rain changes the snow around 7 or 8 a.m. and it’s over by 1 p.m. Given the wet and warm ground conditions are …it is difficult to see with a snow interval of 6 hours in Richmond is going to get over 4 inches of snow.
In Charlottesville the event begins with snow around 4 a.m. and continues until about noon which is an 8-hour window but that region is much colder much sooner than Richmond
in the northern Shenandoah Valley for example the changeover occurs around 2 a.m. in Harrisonburg and it continues until 10 or 11 a.m. ending from west to east. Again this is an 8-hour window of snowfall and some of it’s going to melt.
in Southwest Virginia, locations such as Hillsville will see the changeover around 2 a.m. Monday and it continues until 9 a.m. which is a 7 to 8 Hour window of snowfall
in Roanoke the rain changes to snow around 5 a.m. and it continues until 10 a.m but this is only a five-hour window of snowfall. On the other hand the snowfall rates in southwest Virginia are going to be extremely heavy so it is possible that they could get close to 6 inches in Roanoke metro area.
here is the 18z 3KM MODEL …it shows SIGNIFICANT snows of 4 to 10" from western NC mountains into southwest VA — 14" and ROANOKE !!! ( not happening) then across Richmond across central Virginia to Richmond Charlottesville the central Virginia Piedmont the Southern Virginia Piedmont with even 8 inches as far south is Danville and Lynchburg … and 10 or 12 OR more inches of snow in Tappahannock Fredericksburg Saint Mary's then into the Delmarva including Salisbury Georgetown Cambridge and Easton nto far Southern New Jersey. DC on this map gets screwed big-time. So does Harrisonburg.
But just to show you the impact of the snow depth problem with the wet ground and the warm conditions at the start of the event here is the 18z 3km NAM showing SNOW DEPTH — the difference is absolutely staggering between these two model projections. Maybe the 18z NAM model iss over doing the suppression of the snow build-up. But the trend is quite real.
Given what a simulated radar showing and the track of the system and the warm ground temperature is and the wet conditions at the start of the event I do not see how anybody in Virginia or Southern Maryland is going end up with 10 …12 or 15 inches of snow which is what the GFS in the European models are showing. Look I would love to be able to forecast this much snow it would be great for my business and for my Twitter page and for my Facebook page and for my snow clients. But it's wrong.
This is not about me blowing smoke up my own ass. This is a science and you have to get it right
The jackpot winner of this event is likely to be the Delmarva into southern Maryland and the Northern Neck. The rain changes to snow there around 8 a.m. and continues until 4 p.m. .But at this point the LOW pressure area will be rapidly intensifying as it moves away from the NC coast. Not only will this area see strong Northeast winds up to 30mph … but these NE winds will be pulling in really cold air as the temperatures crash. Moreover this area will be under ‘ COMMA HEAD ‘ snow which is often the part of the storms that has the heaviest precip. The one area which I think could see 8 or 10 of snow from this event would be the central and southern Delmarva regions into far southern Maryland and the Northern Neck
And finally this is really important. The slush and snow on the roads especially secondary roads and bridges and overpasses will freeze hard Monday night. Temperatures are going to crash big time
By 7 p.m. all of Virginia except for the coastal areas of Hampton Roads and the Bay regions will have temperatures between 22 and 26 degrees. The Shenandoah Valley into the eastern portions of West Virginia and interior Southwest Virginia will have temperatures around 20–22 degrees. By midnight most areas in Virginia will have temperatures ranging between 18–24 degrees and that is also the case in most of Maryland and the Delmarva with low teens possible in eastern portions of West Virginia and Southwest Virginia by midnight going into early Tuesday morning.