Okay let’s get back to the weather. The dry slot did in fact make it all the way into the DC metro area overnight with some of the precipitation mixing with sleet and freezing rain at times. For several hours DC had very light snow and sleet mixed and then around 4 a.m. the system the on the coast began to take over and heavy snow redeveloped over DC and Baltimore.

The wraparound band which moved into central VA including the Richmond Metro area early this morning was a complete surprise. Certainly some of the models showed the wrap around  snow extending into central and southern VA over the past few days… but they did not show a band of heavy snow that would drop 3 or 4 inches! That band of heavy snow was restricted to the Northern neck and NOT over central VA.

So yes I was surprised and yes I did not forecast this… and yes I busted for Richmond. However as you went into the Piedmont the snow dropped off dramatically and the sun was out early this morning in Farmville and Lynchburg. I suspect the sun will be out by noon in the Richmond Metro area but the middle Peninsula Northern neck will see heavy snow till sunset where 4 to 8″ are possible.

 This is  the  3rd time  this winter     central   VA  has   been hit  by wrap  around  snow.

The western edge of the Snow Shield which was advancing east early this morning has now stopped. And as a result the heavy snow continues across the DC metro area as far east as Leesburg. However just the Southwest the significant snow has ended for example Warrentown has very light snow and 5 miles visibility and the snow has ended at Quantico and Manassas.

My argument has been that the heavy snow line would push into DC this morning and would end the snow over the DC metro area but continue it across Baltimore and eastern Maryland.

The snow line has very sharp and it was definitely set up along the western and southwestern side of this Low over Northern VA and Central MD… but so far the line has held and it has not reached into DC area. It should buy one or two o’clock this afternoon… but it looks like my last forecast of 6-10″ for Central MD and the DC metro area is going to be on the low side. However for Northern VA … once you get outside of the Beltway in Arlington and Tyson’s corner… the 3-6″ snow forecast seems to be working out pretty good.

Looking down the road we had to things to talk about. First is a southern low over the Gulf Coast states which appears to be inching northward a little bit. However this system is so far to the south that seeing the snow line reach into southern NC from GA / SC is still too far to the south to be overly concerned with the system. We still have some time to watch it but I don’t think of to make it this far north.

The second event is a rather strong piece of energy in the jet stream coming out of Manitoba this weekend. This feature sweeps through the Midwest… passing through MO and ILL into KY much like the current system is! However the air mass around this Upper Low is not as moist and it’s going to have trouble generating a strong Low at the surface. Still if this feature holds together and the models are right we could bring a period of snow to central and northern VA again on the 15th and 16th. I will have more on this in a late afternoon update around 5 p.m..

 

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400pm    FEB   9

MY SNOW  FORECAST MAPS  this   one was issued 1am    TUESDAY  morning . I  probably have the  LEAST snow in the DCA of any  foroecaster around.
http://1664596.sites.myregisteredsite.com/meteorology/1STC.jpg

 this  one at 330pm  TUESDAY   FEB 9..  http://1664596.sites.myregisteredsite.com/meteorology/LAST.jpg

The  12z Models  continue to show   Northern VA and  DCA in BIG trouble  if you are forecasting   10-20″ of snow  as  NWS  yesterday.  NWS has  waaaaaaay too much snow for  HGR ,..10-14 “   and  DCA 10-14″…  despite the  fact that the  main    heavy  snow  Model   — the NAM  d roped DCA to 0.65″ total  and some of that is rain/now mixed.

 NWS has  CHO — charlottesville in  4-6″    which   might be overdone. 

 

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Lets talk about  some of those  very  heavy  snowfall  forecast  for  DCA ? northern VA  and MD.   I want to raise issues with you as to why I see potential trouble for some of those exceptionally high DC metro area forecast that we are seeing from various news outlets and private forecasters as well as those out-of-control irrational weenies.

So I am going to raises several different issues here.

THE LAST MINUTE SEASONAL TREND: as I have already stated in another post we have experienced three significant winter storms — all of them Miller A events –on the East coast since mid-December and all three cases we saw the coastal and 850mb Low jump to the north at the last possible second. I do not know if that trend is going to occur with this system since it is a Manitoba Mauler (MM) / MILLER B event.

DEC 18-19… which originally looked like a major snowstorm even for Central VA saw the trend in the last 24 hours for the 850 Low and surface Low to track N of Hatteras. This enabled some mid-level warming to get in over Eastern VA and the snow turned to sleet in the Richmond area. In addition you recall many of the medium and even short range models were not driving significant snow into New York City: at one point it was only the European model that show significant snow into NYC metro region. As we know 11″ did in fact fall in NYC.

JAN 30 … models consistently showed no snow getting into Washington, DC or snow fall under 2″. It wasn’t until the last minute…24 and 18 hrs before the event began at the NAM and WRF showed significant snow getting into the DC area. In addition if you recall most of the models show a weak 850 Low exiting eastern North Carolina which kept the heavy snow along the Virginia and NC border and south of Richmond. Many of our NC snow fans gleefully watched as model run after model run showed a almost all snow event for Winston-Salem Raliegh Greensboro and even into southeastern VA. Instead not only to those areas turn to sleet But the heaviest snow fell from Richmond North to Fredericksburg and 4 to 8″ fell in DC.

FEB 7. None of the forecasts called for anything other than pure as snow to fall in Charlottesville or Fredericksburg… in either the medium range or short range forecast periods. There was some minor speculation that these areas might experience a little bit of sleet… but no forecasts offered the snow changing over to sleet then rain for several hours. Which is exactly what happened. Again the 850 Low tracked further to the north by 50 or 70 miles which was hinted at only in the last 24 hours before the event began.

ISSUE #2. MANITOBA MAULER. The term comes from the great weather historian David Ludlum. I wish to present to you three particular AND important MILLER B — MM events so I can stress a particular point or two.

These Next 3 images represents the snowfall maps famous KU MILLER B- Manitoba Mauler (mm) events. The From left to right… the great Lindsay NYC snowstorm of FEB 8-10 1969… the great New England blizzard of February 1978… and DEC 30 2008. In all instances is imperative that you see how sharp and amazingly tight to snow greet was on the western side of these systems. New York City reported 22 inches DOV 12″ ABE 3″… FEB 1978 Philly 14-16″… Baltimore 9″ DCA 2″ DEC 30 2000… NYC 13-17″ northeast New Jersey 22″ ABE 3″… TTN 11″ ILG 1″

 

In everyone in these cases models over forecasted by large amounts the extent of the snow in the western and southwestern quadrant of these KU events. In particular some may recall the model forecasts for extremely heavy snow over DC and Baltimore which it failed to materialize.

This next image shows the track of the DEC 30 2000 MM… as you can see the 500 low track through southwestern PA which IS considerably further to the N of where this system is going to track. However if we take the same basic idea and remember that the western side of the MM’s has an extremely sharp snow gradient… and we displace it to the south because Tuesday night & Wednesday’s 500 Low IS going to track over DC / far northern VA… we end up with that western side of the system over a good portion of MD.

That is NOT a good place to be in MM events.

Here are some 500 MB maps for the great February New England blizzard of 1978. These two maps show the track of the 500 Low… diving from southeastern MI into Central VA then east off the Delmarva coast. This track is fairly similar to the track of the system Tuesday night and Wednesday except of course this current system is not diving out of MI. However both the 1978 Upper Low and the Tuesday / wednesday Upper Low due track through southeastern OH and into Northern VA. They ARE similar.

 

Now I am not saying the two events are perfectly analogous. BUT given the 500 MB Low tracks similarities the February 1978 analog do not support a huge snow event for Washington, DC.

 

These next two images show another problem which I concerned for the DC area… and that is the dreaded DRY SLOT. I am a little surprised at how LITTLE mention this is getting in various posts a different one of forums and by several meteorologists who should know better. This is the 0z FEB 8 run of the WRF/ NAM at 60 hrs valid 12z FEB 10…. and we can clearly see the dry slot punching in to the DC area as well as Northwest VA… Western MD and about to move into central MD.

 

This is the 12z FEB 8 WRF/ NAM at 48 hrs… again valid for 12z FEB 10. And again we can see the dry slot punching into the area.

THE 2ND BURST OF PRECIP QUESTION: for the past several runs the GFS and NAM and to a lessor degree the RGEM had been showing a second burst of precipitation over the DC Baltimore area during this event and it is this second burst of heavy snow that piles up the snow totals. Frankly I’m having trouble understanding .

 

 

 

These next four maps show the 18 z NAM QPF in 6 hour time increments… from 30-36 hrs… 36-42 hrs…  42 to 48 hrs and 48 to 54 hours. The first image I have no problem with as we can see the heavy precipitation wrapping up into the developing 850 low over northern VS and eastern half of MD. BUT then we can see at 42 and at 48 hours there is a second burst of heavy precipitation that covers much of eastern MD including Baltimore Annapolis and DC and actually extends into the Northern neck of VA. Finally at 48 to 54 hours we see more uniform band of heavy snow as the coastal low as fully developed.

 

 

 

 

 

What I don’t get is the second band of precipitation developing over eastern Maryland and sitting there for6 to 12 hrs. I don’t understand why the models are developing this second burst in the southwest quadrant of the system…. AND nd why IF this second burst does … it does not move.

According to the 18z NAM this second burst of heavy snow is so impressive that it actually drops Moderate / snow band into the Richmond area for several hours Wednesday morning.

Folks I don’t see how with a 500 low passing north of me… How Richmond Virginia is going to see a period of moderate snow early Wednesday morning. I just don’t see it.

One last point. It would not surprise me at all to see a stunning and impressive snow gradient across central and eastern Maryland. Northeastern MD… say ELKTON could see a lot more snow than Baltimore and Baltimore to see a lot more snow than Hagerstown.