Foot's Forecast | Weather Intelligence

SAT 1/31 AM UPDATE: SHE’LL BE COMIN’ ‘ROUND THE MOUNTAIN WHEN SHE COMES

With the passage of time, all the area NWS Forecast Offices, have lit up with Special Weather Statements galore. But there is still lots of disagreement as to what this storm will do, even among Accuweather forecasters.

Favoring colder solutions: NWS Baltimore, Richmond, State College. Both say this storm will primarily stay a frozen event, with abundant sleet and snow mixed with freezing rain at times. See the statement below posted early this morning.

BAL/DC NWS forecast site: http://www.erh.noaa.gov/er/lwx/

Favoring warmer solutions: NWS Philly, New York. Both say that enough warm air will surge in to change any precip over to rain in most metro areas along the Mid-Atlantic coast. But they also contend that areas N and W of the metro will stay mainly snow.

PHL NWS forecast site: http://www.erh.noaa.gov/er/phi/

All forecast offices have now recognized the error in the computer modeling. Than even with a high of 36 in DC on Sunday, you are not going to eliminate 5 inches of snow pack in one day. The GFS is finally recognizing this with the most recent computer simulations, and has adjusted it’s projections accordingly. So with each passing 6 hour period, the overall look of this storm is trending colder.

I am also working to add some images postings, as well as comment and feedback features on the site, so you can verify my information for yourself if you wish.

SO WHAT’S THE BOTTOM LINE WITH THIS STORM?

A high parked in New England will slowly slide east over the weekend, and continue to funnel cold into and around the Appalachians. Hence the title for today “she’ll be comin’ ‘round the mountain.” This is a classic set up for a major winter storm of the kitchen sink variety… a concept called “cold air damming” is when dense cold air gets trapped at the surface because it has filtered into all the nooks and crannies of the Piedmont and Coastal plain (think anwhere east and south of Harrisburg). A storm moving up from the south does warm the air, but at upper levels first. So the precip falls through the cold air, starting as snow in the north, sleet in the south. As the storm approaches, the sleet goes to freezing rain, and possibly rain. As the storm passes to our east, the return flow brings in colder air, turning everything back to snow. That is the overall scenario I see because the low is projected to track a little closer to us than the last storm.

WHAT ABOUT SCHOOL?

Monday – open all day, no problems anywhere.
Tuesday – all BAL and PHL metro area schools closed due to significant ice.
Wednesday – Easily a 2-hour delay for most schools due to snow on top of ice. However, if snow amounts are higher (at least 4” overnight in Baltimore) they will close again.
Thursday – back to normal, no problems except for some leftover icing.

HERE’S THE PRELIMINARY CALL… I will refine this on Sunday.

In the Baltimore metro area:
Monday – Clear in the morning, but clouds increase all day. High 35. The precip looks like it will hold off now until later in the evening. Overnight, sleet and snow will begin, accumulating an inch or two.

Tuesday – By daybreak, you will see a snow, sleet and freezing rain combo depending on where you are. South of BAL, more sleet, north of BAL, more snow. It will persist and become heavier all day, growing into a significant ice storm with perhaps ½ inch of ice by end of the day. This is not the mist-glaze you had last week. There may be a brief period where it is all rain/freezing rain but I doubt the ground will warm up enough.
High just barely above 32 in the south, less than 32 in the north.

Tuesday night – Northwest winds will bring in cold and and turn everything back over to snow. How quickly that happens dictates how much snow. Northern BAL area could see 2-4”, the city on south more like 1-3”. But remember that will be falling on a THICK layer of ice. Overnight low around 20.

Wednesday – Clearing and sunny but remaining cool, highs maybe 35 but with the snowpack and NW winds, it may end up being colder than that. Weds night everything freezes up solid. Daytime high around 35.

DISCLAIMER: There is the potential this storm produces more snow and less ice if it tracks just a tiny bit more to the east. Amounts in that case are going to be closer to a 6+ range for the Baltimore area.

In the Philadelphia metro area:
Monday - Clear in the morning, but clouds increase all day. High 34. The precip will hold off now until probably after midnight.

Tuesday – by daybreak, snow and sleet will have begun, and NW of the city, it will likely stay all that for most of the day. Due to more warm air present with this storm, snow amounts will be held down from a crippling snowstorm because of the sleet factor. Totals will be in the 4-8” range but there is likely to be a layer of ice under all that. The precip will continue all day, and end as snow showers late in the evening.

Wednesday – Clearing and sunny, some melting as highs just touch 32.

In Central PA (including Johnstown, Altoona, State College)

Monday: Cloudy most of the day, some light snow late in the evening. Highs in the upper 20’s.

Tuesday – snow all day for you powderhounds. Accumulating 6 – 12” by evening.

Wednesday – clearing and sunny but cold. Highs not breaking 30.

AFTER THAT?
Yes, Virginia there is ANOTHER ONE COMING for Thursday night into Saturday.