DEAR NWS… all winter long the model performance in the eastern US even in the short range has sucked moose balls
There are significant changes to this FIRST CALL snow map. These changes are made because of the significant changes in the Thursday afternoon model data — the 18z models -which are all showing a specific trend with the development with the system for Friday night and Saturday. Officially, NWS is still calling for 2 to 4 inches of snow in the eastern portions of Virginia from I-95 east towards the Chesapeake Bay and still have Winter Storm Watches in effect. We believe that is still a possibility, but our snow maps are reflective of the new trends in the data. In other areas, WxRisk forecasts are fairly close to local NWS forecasts in the Delmarva and eastern portions of New Jersey. We also noticed some close similarities between our forecasts and NWS in New York City, Long Island, and New England.
The issue of uncertainty has been and remains a real issue in central / interior portions of Virginia. As you see from the various weather models at 18z, the initial burst of snow which will develop in West Virginia, southwest, and the Shenandoah Valley will probably drop anywhere from 1 to 3 inches throughout the area on Friday evening. As this moisture crosses the mountains, it will fall apart, and this clearly shows up on ALL of the models. Then as the coastal or offshore Nor’easter LOW pressure system begins to develop, a new snow area forms along the coasts across the Delmarva, the Chesapeake Bay, and southeast Virginia into northeast North Carolina.
Because the offshore LOW pressure system is going to form much further to the east than initially forecasted, this second area of moderate and significant snow will NOT reach Interstate 95. This will result in a gap or hole in the snow and precipitation shield from Washington o Richmond but especially in Richmond Virginia. Northern Virginia and Washington DC will see a burst of snow on Friday evening as the dry slot is developing in south central Virginia. The end result for central Virginia including the Richmond Metro area is that this area once again will be caught between two different weather systems that will produce very minimal snowfall.
Indeed, WxRisk has been talking about this trend of a DRY SLOT / gap developing in central North Carolina and pushing into central Virginia for the past 2 days. As you can see from all of the other models on this Thursday afternoon, this trend for the dry slot to push into central Virginia and the Richmond Metro Area appears to be increasing.
In Hampton Roads and the Delmarva, the issue is WHERE does the moderate/ heavy snow band develop and how far down the coast does this band reach?. We still have the 4 inch band covering most of Hampton Roads and the eastern portions of the Middle Peninsula and the Northern Neck regions. We keep the 8 inch snow line out of the Hampton Roads area, but as some of the models show, the development of the moderate/ heavy snow brings the 8-inch snow Line close to the north side of Norfolk and Virginia Beach on the Chesapeake Bay.
Surprisingly the rest of the forecast with regard to snowfall amounts in New Jersey Southeast Pennsylvania New York City Long Island and New England remains pretty much unchanged.
