Saturday, December 15, 2007

ICE, THEN RAIN, THEN ICE,
FOLLOWED BY A COLD WIND

It's Here, Bringing No Good Cheer

SAT 10PM UPDATE: While the uncertainty of this storm reminds me of the Valentine's Day Massacre of this past February, the precipitation type does not. I love the first comment posted by Terpguy of Baltimore region's TV weathercasters. I can simply the whole arrangement for you quite easily: In my opinion, what your National Weather Service Forecast office has posted is outlined well for this storm, and they seem to have delineated nicely the differences in precipitation type, timing and amounts. It is a complicated storm for sure, but does not have to be difficult to understand at our level. I hope my headline makes the big picture more clear for you. Areas west of Frederick, MD will see the highest precip amounts, mostly sleet and freezing rain versus snow. East of Frederick and north of the Baltimore City/County border, light sleet and freezing rain will give way to all rain overnight. In the larger view, it appears our anticipated secondary low is forming along the Carolina coast, and bringing with it deep moisture already convectively active. For areas at or below freezing which have a pocket of this energy cross over from the warm sector to cold sector, you may be woken tonight to the sound of thunder-sleet or thunder-freezing rain!


Think of it this way...most locations in the Northeast, except for the deep interior mountain areas, will see frozen precip changeover to liquid for a time, all then back to frozen before ending with stiff north and northwest winds on the backside. The intrusion of warm air aloft from a stubborn Southeast Ridge combined with influence of subtropical moisture from Olga's remnants are the main culprits to blame for robbing you of a good snowstorm. At this time, I will only be able to focus on the storm's impacts to the North and Central Maryland/Northern VA, Central and Eastern PA, On Sunday, I will start an analysis of potential impact to the Monday school schedule. I will try to take a look at the impact to our readers in the Northeast and New England.

For everyone in this storm, the one event that seems near certain is a refreezing of all standing water Sunday night, coupled with strong winds creating power outages overnight. A second Arctic High will arrive as the storm departs Sunday, sending temperatures into the 20's across the region, encasing all untreated roads, parking lots, sidewalks and your front step with a glaze of ice. My biggest concern is the school schedule situation for Monday, considering the potential for strong gusty winds, downed power lines, slick roads and widespread icy spots due to the refreezing. Right now, delays seem quite likely from Carroll County, MD east. In areas experiencing the sleet/freezing rain, temps will remain lower and re-freezing occurs more easily tomorrow night, so I could see Northern VA schools closed, as well those in and west of the Blue Ridge.


In the comments, please consider posting a run down of what your local TV weathercasters are projecting, as well as your observations on when precip began at your location, and what type it was. Sunday afternoon, once we see the winds materialize and get a sense of overnight temps, I'll post a final call for schools Monday morning.

30 comments:

terpguy said...

0800 local, Friday.

Consensus of the three local channels about the weather this week end:

They'll be some, uh, winter weather, uh, starting at, uh 4, no 7, no 11, on Saturday...It'll be be rain, then freezing rain, then sno...wait, it's snow then rain then free..no that's not right ...freezing snow, then, I mean snow, then sleet.... uh-h-h...
Anyway, It will continue until Sunday AM, er, I mean PM... that is Monday...uh-h-h...

Jury is still out folks.

Check out Foot's Call later!

Tune in tonight for an update!

Tom said...

Dr. Foot:

I am flying on Monday morning from PHL to ATL. Will the weather warm up enough on Monday AM between 6:00 AM and 8:30 AM to keep flights from being cancelled or delayed. Do you think they'll be de-freezing planes even if the runways are dry and the weather is warmer than 32F? These de-freezing episodes can take a lot of extra time early in the morning because so many flights are headed out at the same time.

PP

Christopher said...

Mr. Foot, my band is playing Chevy Chase Saturday night. I also have to be back in State College Sunday to study for my grad school finals. Am I toast? Should I cancel my gig & go straight back to PSU tomorrow? Or should I wait until Sunday to leave?

Mr. B said...

Hello Ice Storm. .90" of FZRN forecasted on the NAM. Weeeee.

Mr. Foot said...

Chris.. that's a complicated weekend schedule. But being a PSU grad myself and knowing how the roads can get heading that way, there's no good answer to your predicament.

The one possibility in your favor is that PSU has been more prone to cancelling classes in bad winter weather than they used to. I remember a 27" storm in March 94 that did not cancel classes, nor did it happen that Jan when the high temp did not crack 0.

This was during the years of stodgy Joab Thomas. The Graham Spainer effect, it seems, has leaned more in favor of the student during bad weather.

Bottom line, you are facing ice all the way around... from MD north. Best plan would be to study here, then wait as long as you can Sunday...leave around noon when the changeover to rain occurs.

I'm guessing you take 83 to Harrisburg, then on up 322 etc. The farther east you are, the less ice you'll encounter.

Good luck, drive slow and have lots of coffee handy!

Prospero said...

Hi, Mr. Foot

I remember that 1994 blizzard at PSU well (I was a sophomore there then). It hit the Thursday before Spring Break -- if I'm not mistaken, they did cancel classes that Friday. I was long gone by then.

When the temps were below 0, they did cancel classes one day after 3pm.

Have to love good ol' Joab Thomas. I like the Classroom Office Buiding (COB) better before they re-named it after him.

wvm said...

Mr Foot,is it just me or does it appear that most of the precip is going way north of us. I was wondering if our main "stuff" is going to come from some type of wrap around off of the coast.

NeedaSnowday said...

(sigh).. pretty dog-gone discouragin' huh?

snow lover said...

hey
i dont know why every one is so disguriged i just looked at a weather post and it said that it looks as if a lot more cold air is damming east of the appalchians so that would create winds from the north and they would blow cold air south and the secondary low would develop farther to the eas so mD gets a lot more ice. I think this could be a major ice storm!!!!

Russ.L said...

Snow Lover
where did you get that information? Just on the way it looks and feels, it sure feels like something more than rain/mix!!

snow lover said...

hey
i got that info at accuweather.com their blogs the madman he gives great info check it out.

emsays said...

Mr. Foot,
I am taking 22 kids to annapolis tomorrow to perform for the Governors open house and to the Dundalk United Methodist Church. Should I plan on canceling due to weather?

NeedaSnowday said...

On ABC, Joe Lundberg,an accuweather forecaster just said "the good news is that it will miss the I-95 corridor.. they will be spared"....

Julee said...

Who needs Accuweather?

The beleaguered gentleman replenishing the milk supply at my local Giant at 2 o'clock this afternoon was announcing (in a very loud stage whisper) "It's only going to RAIN people! It's ON-LY going to RAIN!"

Wonder who HE knows?

Mr. Foot said...

prospero..(great handle name BTW)..

I stand corrected, I am thinking back about that storm and you were right, in Feb 94 classes were cancelled last day. I thought storm arrived daytime Friday, but was Thu night.

As for the Jan 94 cold outbreak, I remember how stupid it was when PSU closed at 3PM. I was editor of the renegade newspaper "The Lionhearted" and recall like yesterday trudging across the frozen wastelands between Kinkos (where I worked in the daytime) to the paper office for the evening. Twas windy and miserable, a rough winter all the way around.

Not like the bad new days of global warming.

Mr. Foot said...

emsays:

Definitely take your trip. Unlike PSU Chris, you are heading south into the warm sector! I bet Annapolis sees very little frozen precip out of this and if it does, will be washed away by the time you're on the road. Best wishes to you and the kids for a safe performance!

Prospero said...

Mr. Foot,

It was no picnic. I lived in East Halls, away from ... everything. I was in McClanahan's when the announcement came through. It was like the liberation of Paris.

I remember that winter well. It seemed like it snowed EVERY Wednesday. I remember a huge storm came right at the beginning of Spring (ha!) '94 semester. Then a warm front came through, thawing most of it and making slush. Then came the deep freeze and froze everything under the snow. It was as if PSU was a huge ice rink for all of January.

If I recall, when I left for home (Reading, PA) that May, there were still some snow drifts in shady areas.

Nasty winter, that one.

Right now, I am lamenting the rain.

Prospero said...

PS -- 9:30 in White Marsh. Rain is coming down.

** sigh **

Mr. Foot said...

9:45 Light Rain in Dundalk at 35 F

Looking at the radar, we are going to get slammed overnight and I'll just burst the bubble now.. guessing NWS will yank the Winter Weather Advisory for southern half of the region (incl. srn Balto County). However we are in the minority (powderhounds) because many other areas, the Blue Ridge, Central PA, SW Virginia are still going to get hammered with either freezing rain (southern Apps) or sleet/snow to the north.

I am thinking northern Balto, Carroll, Frederick Counties could see a sleet/freezing rain storm before a change to rain. If temps are 35 along the bay where I am, they are probably closer to 32 or lower in interior areas west of I-83. Anyone over there to provide observations?

prospero..you made me laugh, you are exactly right about the WED thing that winter. I was volunteering with a Boy Scout Troop in State College (on top of all the other distractions I had going)..and our winter awards banquet was postponed about 3-4 times...as I remember it did snow every Wednesday for at least a month, was amazing, about 4-5 inches each time. The 27" storm collapsed the dining hall roof at Seven Mountains Scout Camp, leading to very fast construction of the nice one they have now.

NeedaSnowday said...

In the Lutherville-Timonium area we have rain and 35-36 degrees at 10 PM ... plus a crappy game on the NFL Network..

Julee said...

Mr. Foot,

Temperature in Monkton (in The Hereford Zone) is 29.4, winds ENE at 2-4 mph.

It's raining there so I'm sure things are icing up.

wvm said...

We have a steady rain here in
Berkeley Co., WV and our temp is right around 31. There may even be some sleet mixed in. It is hard to tell. We have ice on pretty much everything except the roads so far.

NeedaSnowday said...

Heavy rain now!!

Chris said...

Mr. Foot,
Do you think the Hereford zone in northern baltimore county might get off on monday? and how bad will the roads be monday morning? Thanks alot for any help you can give.

samplerknn said...

In Norrisville at the moment we have icing, although it is still coming down as rain. This is the Northwestern tip of Harford County bordering on York (PA) County.

Mr. B said...

Mr. Foot

Over .30" of ZR here so far.

31.6 and holding steady.

Some ZR and IP right now.

Christopher said...

I decided to go through with my gig in DC (which was KILLER!)--- now I just have to make it back to PSU Sunday! Thanks for the advice! I'm hoping that it will just be all rain by the time I get to the mountains before Happy Valley!!

Wishing.for.Snow said...

In Sparks (Hereford Zone), 5:30 am, light misting rain, 40 degrees. What happened? I was so looking forward to getting "frozen in"!! :(

Mr. Foot said...

Morning all.. I awoke to what I expected in Dundalk..windswept rain and 40 F. I see that most the locations that were icing went over to rain. While I expected that too (the frozen-liquid-frozen bit from yesterday), I can hear the collective sigh from across the lands. It does just seem wrong and sacreligious to have a nice pretty coating of ice get washed away so quickly.

What happened was "strength" of the warm air intruding aloft, which scoured out the marginal cold air at surface, east of the mountains. Mr. B and wvm out in the hinterlands saw what we thought they;d get..freezing rain.
Influence of subtropical moisture really revved up the secondary low as some of you observed with the heavy rain overnight.

Chris..glad you went for it. Once I saw the radar across DC, figured your plans would be ok. Only trick now is to get on the road quickly and head north before winds shift to the NW and colder air rushes in to freeze standing water tonight. If it were me, I'd leave right now as I see a dry slot on the radar working in between the two lows.

Welcome to wishing.for.snow and samplerknn to the group. The best chance for delays has a lot to do with how quickly the shield of precip to our N and W breaks down.

This is an age old rule I follow.. the primary low always seems to stay stronger longer. The benefit of that is areas east of the blue ridge are caught in this "occluded zone" until the last second. That prevents surface moisture from evaporating, and allows cold air to arrive quickly once everything clears. For those wishing a delay or closed, we'll have to see rapid refreezing in the overnight hours.

But there's still a lot of precip and energy stretching back to Chicago.. A long way to go before its over.

Christopher said...

Hah! I made it alive--- I left at 11 AM---- the mountain wasn't bad, but 322 S of Lewistown was a bit crappy.