FIRST CALL SNOW MAP FOR MARCH 20-21 MID ATLANTIC WINTER STORM
STAR DATE 201803.18
The main change and the midday or Sunday afternoon weather models has to do with the change in the track in that position of the SECOND event / LOW w pressure area on March 21. These changes in all of the Sunday afternoon data means MORE snow than previously forecast may occur over northern DEL ...most of MD ... the northern third of VA ... eastern WVA Panhandle on the 20th and on the 21st (and into southern NJ)
Over the past several days the weather model data has consistently kept the 2nd Low to south and pushed it off the North Carolina Coast.... at times tracking it over Cape Hatteras. This allows for the colder temps with the second LOW on March 21 ... and the snows staying pretty much south of DCA areas . And as I stated in the previous update ..over the past two days... most of the model data has shown consistently that the best areas for accumulating snow on March 21 would be southwestern VA as well as central (Richmond metro) ... east central VA (Middle Peninsula & Northern Neck) ... southern MD and the central DEL .
However the SUNDAY afternoon data has changed the track and position of this second LOW on March 21. This keeps areas such as southern New Jersey ...northern Delaware ...most of Maryland... the northern third of Virginia in the snow area for a longer period of time on March 21. It also reduces the amount of snow over central and east central Virginia. The snow stays about the same over southwest Virginia ...southern portions of West Virginia ...and eastern Kentucky because the upper level energy of the second low passes over this region.
1. Please keep in mind that snow forecasts in MARCH are always a a high risk venture in the Middle Atlantic region .
2.Elevations matters... Again areas which are above 1000 feet in elevation will do much better and see much more accumulating snow than areas under 500 feet in elevation
2. This shift in the models on this Sunday afternoon has been across the boards and on all the data that I have seen. So even though it is a significant shift ...it is one which cannot be ignored.
3 This could be the biggest of the season for Washington, DC metro area (but that is not saying very much) and this also could be the biggest of the season for the Baltimore metro area as well as southern New Jersey.
The main interval or period of snow for the Eastern third of the state of West Virginia (WVA panhandle) ... northern VA ..MD ...DEL will begin Tuesday morning. Again Initially it WILL BE rain over metro DC / northern VA into central and northeastern MD d including BAL.
The changeover will occur Tuesday morning from northwest to southeast between 11:00 AM and 4:00 PM.
As cold air comes southward the rain will change over to snow even by Tuesday evening as far south as Fredericksburg Charlottesville Lynchburg and Roanoke. By 2:00 AM Wednesday morning the rain may change over to snow as far south as Fredericksburg and Richmond
By Wednesday morning March 21 there will probably be two areas of snow. The first area will be over the Northeast big cities extending from NYC to Richmond Virginia including the DC Baltimore and northern Virginia ...the northern Delmarva ...and all of the southeastern Pennsylvania /Philadelphia metro area as well as most of New Jersey.
The second area of snow will be over Eastern Kentucky... the southwest third of Virginia ...southeastern Ohio and southwest portions of West Virginia. the snow in both of these areas will continue into Wednesday afternoon. By Sunset Wednesday the entire event will be over.