US SNOW COVER AT 10+ YEAR HIGH

The recent push of the western trough east creating a favorable environment for frequent large scale snow systems along with widespread, early season cold has increased the snow cover significantly across the US. On December 1st,  20.2% of the US was covered with snow. By December 9th, that number increased by almost 47%!  Only 2009's increase of 44.3% in the first 9 days of December has even come close. 

Last year's snow cover map vs this year through December 9th:

December 9, 2012

December 9, 2013

FRIDAY'S Winter Weather Update: RADAR, SNOWFALL FORECAST

CURRENT RADAR IMAGE FOR NORTHERN OHIO AND OHIO VALLEY



Temps have dropped 30+ degrees over the last 24 hours in northern Ohio.

Look at the temperatures across the Great Lakes yesterday vs this morning

A light dusting of snow/sleet late last night has moved south with a break. The main area of snow (circled in red at the lower left) is now converging across southern Indiana. Expect this snow to make it into northern Ohio by early afternoon.

Here is our SNOWFALL FORECAST FOR TODAY

Winter Weather Update: COLD AIR COMING, WINTERY MIX, SNOW!

WINTER WEATHER ADVISORY FOR NORTHERN OHIO FOR FRIDAY -- ACCUMULATIONS HAVE BEEN INCREASED FOR FRIDAY. 1-3 IN CLEVELAND; 2-4 INCHES MEDINA; 3-5"+ AKRON, CANTON SOUTH. MORE UPDATES ON FOX8 NEWS

Temps early Thursday made it into the lower 60s. This marks the third straight day with temps above 50; 2 days in the 60s. The arctic air will affect Ohio in two waves. The first is late Friday and Saturday. The stronger one is next week. If we stay in the 20s on Saturday after 60s two days prior is a rare occurrence.  It hasn't happened since 1972!

Two waves of winery weather will develop along the temperature boundary later this evening and tonight.  It glances northern Ohio with some sleet/wet snow with no significant accumulations. The second wave is the "biggie". That develops on the same boundary tomorrow morning. Snow will converge along the front/boundary and start accumulating by midday.

Here are the preliminary accumulations for Friday:

Get ready for a repeat of this late Sunday and Monday....sleet/ice and snow. This time, the temperatures will DROP MUCH MORE behind it next week!

HIGH TEMPERATURES FOR TUESDAY AND WEDNESDAY!

Winter Storm FRIDAY...Arctic Air Coming In Two Waves

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WINTER STORM WATCH NOW ISSUED FOR SOUTHERN OHIO FOR FRIDAY. DETAILS AT THE BOTTOM OF THIS POST.

I'm still not convinced that this first push of colder air this weekend will be as strong as advertised. The mean trough stays west of Ohio on Friday and into the weekend. The 500mB flow is out of the southwest so the advection of cold air is more south than east. The core of the cold air doesn't slide east until early next week as the trough migrates into the Great Lakes.
 

I'm not saying that the temperatures won't fall, I'm just a bit hesitant on bring in a 28 degree high for Saturday this far out (I'm writing this Wednesday morning). I've been consistent with my reasoning since Monday. Unless the overall flow changes in the models Thursday or Friday, I'd rather keep the temps in the lower 30s and adjust down if need be. A 5 degree variation is probably more semantic than anything else. Rarely does someone feel a difference between 28 and 33. But this pattern, as I see it, will no doubt occur again later this winter if the mean trough stays in the center of the US. Better learn the specifics now than be blindsided later...Now to the specifics of the Friday forecast:

Temps will start to fall Thursday but as I said earlier, the winds will parallel the front. So the front stalls and a low develops along it over the panhandle of Texas. It moves along the sharp temperature gradient along the Ohio River.

So the dividing line between rain and snow will bisect Ohio. Expect precipitation to move in fast tomorrow (Thursday) night and early Friday.
 

The movement of a few miles will greatly affect how much snow we get and who see it Friday. The European model is fairly aggressive with snowfall amounts for all of Ohio. The heaviest snow seems to stay south. Stay tuned for more adjustments to the snow amounts and locations.

November Summary for Cleveland and Ohio

Thanksgiving is over. The weather is beginning to quiet down. The snow cover has finally melted. What a better time than now to look back at how November stacked up versus last November and other Novembers of the past. Was it colder than last year? How cold/warm was it? Did we see an abnormal amount of snow? The graphics below should shed some light on this.

The overall pattern has featured a trough across the Great Lakes with the ridge out west. This allowed bursts of colder air to drain into Ohio. Notice that last year, the trough was out over the eastern seaboard. The western ridge was stronger and further east.

First the temperatures:  Over the last 4 years, much of the US had above normal temperatures with the exception of the east coast. This year, most locations east of the continental divide were well below average.

Yet here in northern Ohio, the average temperature this year was not much colder than last November. The November temperatures over the last two years were below the 30 year running average. November 2013 was the coldest November since 2000.

Even when you look at the average high temperatures (not counting the overnight lows) the numbers are similar to 2012.

The true indicator lies in the extremes. The number of days above 50 degrees were identical to 2012...

...yet the number of days below 40 degrees was far and away higher than last year, second only to 2008, third highest in 17 years.

How about snowfall? More than 2/3rds of the state had at least 2" of snow. The last time that happened (eyeballing this) was in 1980!

Cleveland snowfall was the highest since 2008, just slightly above the 4.4" average.

UPDATE: Significant SNOW for NE Ohio!!!

Courtesy: Cleveland Public Safety

First, some clarification on winter watch/warning definitions: A WINTER STORM WATCH means there may be hazardous winter weather due to heavy snow. Heavy snow means 7 INCHES OR MORE of accumulation in 24 hours or less. They are issued at least 12 hours before the hazardous winter weather is expected to begin. When the storm becomes imminent (inside 12 hours of occurring) or has a high probability of occurring, watches are upgraded to a "WARNING" which was done yesterday for select counties.

Leading edge of the snow is pushing into southern Ohio. CLICK ON THE IMAGE BELOW FOR THE CURRENT RADAR OVER OHIO

 

The timing of the snow looks like this: SNOW IN AKRON/CANTON/NEW PHILLY BY 2PM, CLEVELAND BY 3PM. AFTER THAT, THE SNOW SLIDES WEST.

Accumulations from TUESDAY LATE AFTERNOON through WEDNESDAY LATE AFTERNOON look like this. Most of this will fall this evening and tonight:

Hazardous travel through western PA and western NY state. The major airports along the east coast will only see rain from this system. Any flight delays will trickle down from the inland airports like Hopkins in Cleveland, Pittsburgh, Buffalo and Rochester.

Nor-Easter Developing: Heavy Snow Imminent

WINTER STORM WARNING FOR ASHTABULA, GEAUGA, TRUMBULL, PORTAGE, STARK, MAHONING AND TUSCARAWAS COUNTIES FROM 12PM TUESDAY TO 4AM THURSDAY. First, some clarification on winter watch/warning definitions: A WINTER STORM WATCH means there may be hazardous winter weather due to heavy snow. Heavy snow means 7 INCHES OR MORE of accumulation in 24 hours or less. A "WATCH" is a long range prediction. They are issued at least 12 hours before the hazardous winter weather is expected to begin. When the storm becomes imminent (inside 12 hours or occurring) or has a high probability of occurring, watches are upgraded to a "WARNING"

The active pattern continues in the month of November. We've already had a little over 3 inches of snow at Hopkins (more in the snowbelt), the most since 2008 through the 25th of November. Our high temperature Sunday of 26 was the coldest daytime high AFTER the 20th since 2005 when we only hit 24 on the 25th. Prior to that, you have to go way back to 1976 to find a colder high temperature during the last 10 days of November.

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Now for the setup this week: The 500 mB steering currents show a trough digging across the east. Notice that the clipper low is starting to phase with the panhandle low to the south. So that by Wednesday afternoon, both lows are completely absorbed into the mean somewhat negatively tilted trough. In conditions like this, the low can amplify (get stronger) very fast due to the sharp variations in conditions to either side of the trough.  Higher levels of instability can develop which can create bursts of heavy snow. Fortunately, I think that this will occur in western PA and upstate NY.

MONDAY EVENING

TUESDAY EVENING

WEDNESDAY AFTERNOON

The US radar is already showing the merging of the two systems...

 

The snow from the clipper will be the first wave of light snow tonight. Accumulations will be small, perhaps an inch in spots by early Tuesday morning.

CURRENT RADAR LOOP HERE

The future radar loop (high resolution NAM 4 km) shows distinctly the clipper snow coming in from the northwest, a break, followed by the panhandle snow/rain from the southwest. Here is the youtube clip. Watch the time clock at the top of the video. 

Heaviest snowfall amounts still seem to reside in the eastern counties closest to PA. The latest bring back some of the heavier snow west. Here is our updated snowfall forecast. The NWS forecast is lining up very well with our forecast so I'll go with their numbers. Remember, this is just guidance as snowfall will vary a bit from place to place.

Why is Lake Effect So Localized?

Why is lake effect snow so localized? Moisture often times converges in pockets or streaks depending on the weather setup. Check out this great visible satellite photo which shows the streaks of clouds cover and sunny breaks in between. Each streak of cloud cover has bursts of lake effect embedded within it.

BTW, the 850 mB temperatures will be falling to -18 with a lake water temperature of +8 (yes, all in celsuis). You need around a 13 degree temperature difference. Notice that later today, tonight and early tomorrow, temperature differences approach 25! This means heavy bursts of snow IN LOCAL AREAS!

Saturday afternoon radar image...CURRENT NORTHERN OHIO RADAR LOOP HERE

How Rare Are "NOVEMBER SEVERE WEATHER HIGH RISK" Forecasts? VERY!

Damage from Washington, Illinois (Chicago Tribune)

Several requests on the history of MODERATE and HIGH RISKS for the US and OHIO in November. I found some answers on the Storm Prediction Site.

Only 2 other instances where the Storm Prediction Center issued forecasts for HIGH RISK FOR SEVERE WEATHER in November:  2002 and 1998.  None of these HIGH RISKS were for any part of Ohio. Both of these featured large tornado outbreaks.

Image courtesy Greg Carbin, SPC

This is what Sunday's event looked like with storm report dots superimposed over the risk areas

Image courtesy: Eric Fisher/Jesse Ferrell on Twitter

Only 10 MODERATE RISK AREAS have been issued in November since 1998. 4 of the 10 were issued on the same date or later in the month. NONE WERE ISSUED IN OHIO!!!

Image Courtesy Greg Carbin, SPC

Aerial Photo of Tornado Path in Washington, Illinois

Notice the swirls along the path. This tornado was on the ground for 46.2 miles a an EF4 which had winds between 170-190 mph. This tornado had winds greater than any hurricane or Typhoon in recorded history!

Here are some other aerial photos courtesy of the Chicago Tribune.