LAST CALL SNOW FORECAST MARCH 21
This remains a very tricky forecast unless you are over the interior areas of the Middle Atlantic but I do think we are seeing some important trends and pieces are falling into place. First let's talk about the new and final LAST CALL MAP. There are 2 images I am presenting here -- one of them is s enlarged focusing on the areas from New Jersey to the Carolinas and out into West Virginia.
I have shifted the 4 to 8 inch snow line into the Washington, DC metro area and south of Baltimore and very close to the areas just north of Charlottesville and Fredericksburg Virginia. To the south of those areas the snow amounts of Charlottesville and Fredericksburg COULD drop off sharply.
I have expanded slightly the 8 to 12 inch snowfall area and I have added a 12 to 16 inch snow band (which I was thinking of putting in yesterday but held off). As you will see the overnight and midday data is very strong that in these elevated areas ...the snow amounts will be greater than 12 inches.
In northern New Jersey / New York City I have kept them in the 8 to 12 inch area even though NWS and other private forecast services are forecasting snow amounts much higher than mine. This is also the case in New Jersey and Philadelphia. There I think the NWS and The Weather channel are really out to lunch and mis- reading a lot of the data. This image ( crom crankwx guy) shows SIGNIFICANT areas and amounts of sleet over NJ NYC se PA/ Philly.
These two images show the early morning and current afternoon radar over the Middle Atlantic region. at 245PM. It seems that the FIRST LOW is now bringing heavy snows over Philadelphia and interior portions of southern New Jersey ...northern Delaware just to the north of Baltimore and northeastern Maryland. There still appears to be areas of light to moderate snow in around Frederick and Hagerstown as well as York in Lancaster Pennsylvania.
One of the primary problems and difficulties in this WED snowstorm has to do with
1) the snow ratio
2) how hard the snow comes down
3) rate of snow accumulation.
The only place where things are pretty certain or definite are in the areas over Northwest 25% of Virginia ... the eastern West Virginia panhandle ..much of western and central Maryland ...into south central Pennsylvania and close to Philadelphia ...and then up into interior eastern Pennsylvania and northern New Jersey. All those areas are about 700 above sea level and some areas are over 1000 feet above sea level. This is going to have a significant impact on the snow amounts
This image is the early Tuesday morning EUROPEAN Model that came out at 130am and its snowfall projection from the enhanced European model (wxbell). It shows snowfall over the next 24 hours ENDING as of 8:00 PM this Tuesday evening. As you can see it has a large amount of snow up to 12 inches over portions of the eastern West Virginia panhandle and far Northwest Virginia (Winchester and Martinsburg). It also shows 8 inches into much of central Maryland and into Baltimore and 6 inches into Washington, DC --all by 8:00 PM this evening.
Obviously this is not going to happen. Indeed as you can see by the radar ... most of the heavy snow is now with the north of these areas. Part of the problem with this enhanced the European model is that this particular version views sleet and snow as all snow.... and rain snow as all snow.... and rain and sleet as all snow. Clearly that is not the case and that is why the snow amounts on this model is way off.. The 0z 3km NAM (without counting sleet as snow ) did a GREAT job with todays snow over northwest Virginia .. eastern WVA western / central Maryland
Indeed the Tuesday afternoon European model has a huge area of 16 to 22 inches snow over far northwest Virginia... the Eastern West Virginia Panhandle ...all of central and northern Maryland ... south central Pennsylvania and into the Philadelphia metro area. This is not going to happen --it's just nonsense.
That kind problem is similar to what the other models are showing. These other models all focus on the idea that any sort of mix precipitation that falls over the next 36 hours will be counted as all snow. Moreover they all are assuming a 10 to 1 snow ratio and that too is an issue.
These two images show the potential snow ratio over the Middle Atlantic regions at 8:00 AM and at 2:00 PM Wednesday. As you can see most of ratios are under the text book 10 to 1 snow ratio . This means that you can no longer take the snow map forecasts / projections at face value ... and you have to adjust for them.
Now lets looks Model radar simulations and see how they are handling this which will provide us with more detail. These two images show what the radar will look like at around by 7:00 PM and 11:00 PM this evening. Notice the large dark blue area of snow developing over southwest Virginia. That is part of this SECOND LOW that is beginning to form and notice also the increasing amounts of rain which appear over central and eastern North Carolina. Over much of Virginia and northern West Virginia.... not much is happening during the evening hours
By 3:00 AM Wednesday morning moderate to heavy snow has broken out across all of Western Virginia and southwest Virginia ...up to the Blue ridge mountains and the snow extends heavily backed into large portions of West Virginia and Eastern Kentucky. Notice that to the east of the Blue Ridge ..the precipitation is mixed and a generally rain over much of central and eastern Virginia as well as northern Virginia into the Washington, DC and Baltimore metro areas.
By 8:00 AM Wednesday morning heavy snows pushed east region most of interstate 95. The rain/ sleet line in will be changing over to snow around this time in Washington, DC Fredericksburg and Richmond Virginia. Behind this line there will be moderate to heavy snow covering all the Virginia Piedmont ...as far west as central cest Virginia and Roanoke. There may even be some snow into northwest portions of North Carolina. East of interstate 95 it still either mix precipitation or rain across the Delmarva Baltimore most of the Chesapeake Bay into southeastern Virginia.
By 2:00 PM Wednesday heavy snow was falling across all of Washington, DC Baltimore and southern Maryland and the heavy snows has moved into the western half of the Delmarva and the Northern Neck. Moderate to heavy snow extends out into Winchester and Leesburg ...most of western and central Maryland and the Eastern West Virginia panhandle. Moderate snow extends into Charlottesville as far west as Lexington and as far south as Richmond.
By 8:00 PM on Wednesday all the snows over r western and central and southeast Virginia has ended. Moderate snow still falling over Washington, DC and Baltimore metro areas as far west as again the Winchester Leesburg area and eastern West Virginia panhandle.
What this data shows is that the snow duration over the southern Virginia Piedmont into central Virginia and the Richmond / Fredericksburg as well as the Middle Peninsula and Northern Neck will NOT see long duration of snow on Wednesday morning to the midday. At best central and east central VA will see about 4-6 hours of snow from what the data is showing.
Clearly the heaviest snow will be over the areas just to the north and west of DC and Baltimore and this includes areas such as Hagerstown Winchester Frederick and much of south central Pennsylvania including Harrisburg Lancaster York and Gettysburg. This will also be a significant snowstorm to the entire northern half of the Shenandoah Valley and the West Virginia eastern peninsula.
In New Jersey the forecast is much more difficult. These images from 12z 3KM NAM clearly show that during the morning hours to midday on Wednesday there will be significant rain over central and southern New Jersey. It does NOT does not change over snow until 4-5 pm on Wednesday. The problem is that all the precipitation end over New Jersey by 1:00 AM on Thursday morning. This means that central and southern New Jersey will see 9 hrs of snow of snow. This makes it very difficult for snow amounts of 8 to 18 inches to accumulate over these portions of New Jersey -- which is what NWS and others are calling for. Now if the Mixed precip goes over to all snow in NJ by say 10 am Wednesday... THAT would give NJ a much better chance of reaching 12"
I also have some issues with some of these heavy snow forecast into New York City which I think is also overdone to some degree.
One last point is that there is another system coming Saturday night and Sunday and it also has a potential bring significant snow accumulations because it occurs a night time. The model data it brings this system in from Chicago through Indiana Ohio and Kentucky into West Virginia and into southwest rn and central Virginia. It looks like the snow stay south of DC but this could be a significant snowfall for Roanoke Lynchburg Lexington Charlottesville Stanton into the Richmond metro area
NOW LETS SEE NWS FORECASTS