Latest on the Winter Aspect of this Storm

#Ohio #Indiana #Kentucky #Snow #Accumulations

At this point, I really have nothing to add.  Modeling has been pretty much within a small margin of error on what is going to occur this afternoon through the morning tomorrow.  A wobble north or south can still occur, but barring any significant shift things are pretty much set in stone.

Wednesday Afternoon:

WedAfternoon

 

Thursday Afternoon:

ThursdayPM

Snow will overspread the region from southwest to northeast this afternoon into early evening and become steady (heavy farther south) for periods late evening through mid-morning.  Snow will end northwest by early morning and far southeast by Thursday mid afternoon.

The margin of error, while small, is still significant because a subtle shift in any direction (north or south) can impact areas greatly in close range.  This is quite common with systems like this.  Bring the low north about 15-30 miles, you can double snowfall amounts in areas that are expecting only 1-3 inches.  Shift it south, and places that are expected 4-8 inches get 2-4 inches.  It is that sharp of a cutoff.

NAM 12KM Snowfall at 12Z:

Wed12NAM

 

0 to 2 inches in northwest regions to as much as 9-13 inches southwest into south-central regions.  Probably a bit of overestimation due to some sleet at times.

GFS Snowfall at 12Z:

GFS12Wed

0 to 2 inches in the northwest parts of the region to as much as 9-14 inches in southwest areas.  Much like the NAM, a little overdone with some snow in high total areas being sleet accumulation.

Canadian Snowfall 12Z:

Canada12Z

Canadian appears to be a smoother, broad brush so things will vary a bit, but 1 to 3 inches in the northwest to 7 to 10 inches in the central and southeast.

This is why a margin of error is still out there.  These are not the only models that have been looked at because some show more and some show less, but an aggregate total can be assessed.

I will break it down into 5 zones, northwest, southwest, northeast, southeast, and central.  The city center’s of these sections will be Indianapolis (NW), Owensboro, KY (SW), Cambridge, OH (NE), Jackson, KY (SE), and Wilmington, OH (C).

The way it looks in the Northwest zone: 0 to 3 inches, Southwest zone: 3 to 10 inches (sleet potential), Northeast zone: 3 to 8 inches, Southeast zone: 4 to 9 (sleet potential), Central zone: 3 to 7 inches.

Update on the Winter Storm Scenario for Tomorrow into Thursday Morning

#Rain #Cold #Snow #Accumulations #Ohio #Indiana #Kentucky

The brief warm up and associated freezing rain, sleet, and snow before periods of rain worked out quite well for Tuesday.  Some places got into the lower and middle 50s with even lower 60s in far southern Kentucky and West Virginia.  Now the battle is on with the deepening of the low versus the speed of the cold front.  This will determine the northwestward extent of the snowfall for Wednesday late morning through early Thursday morning.

Wednesday Morning:

Graphic12

As displayed, the cold front will slip by overnight into early Wednesday morning bringing an end to the rain.  At the same time, this will allow the cold air to bleed back into the region.  With the warmth ahead of the front and cold air trying to bully its way back in, a weakness will occur and spawn waves of low pressure along the front.  The deeper and stronger these lows are, the slower the front will sag to the south and the more northward the moisture can surge into the lower and central Ohio Valley.

Wednesday Night:

GraphWedNight

You see two lows along the front.  One in north-central North Carolina and another in eastern Texas.  If you look north of the front you can see the wide deformation zone of snow.  When you focus in on our region, you can see a definitive cut-off line along far southwest Indiana and ride up across southwest and central Ohio into southern Pennsylvania.  That is why this is such a agonizing storm because the northern reaches get little to none but in just a 50 mile southeast jaunt, one could expect more than 6 inches of snow.  It is that tight.

Country Warnings Map View:

Countrywarn

To really put the focus on the line of demarcation, check out all the Winter Storm Warnings in pink and follow the northern extent.  While Interstate 71 does not begin until Louisville, Kentucky but if you run a best-fit line from Louisville back into Missouri on the southwest and then run the best-fit line from Louisville to Columbus, Ohio, you now see why Interstate 71 and points south and east were the focal point for heavy snowfall potential.  This is a classic boundary point for these types of storms to move and it will be the case this time.

Warnings Map:

Wilmington NWS

WarnMap

 

Louisville NWS

LOUNWS

Jackson NWS

JACKNWS

Bringing it closer to home, please excuse the green and turquoise color, as those represent flooding scenarios, but the blue Winter Storm Watch runs just north of Interstate 71 and the pink Winter Storm Warnings run along and south of Interstate 71 up to and just south of Interstate 70.  This is the proverbial threading the needlein the haystack because 50 miles will be the difference between partly cloudy skies and heavy snowfall.

Trying to put numbers down at this point is hard because some adjusting in the model is likely because we are dealing with this part of the storm this evening into the morning, then we can get a better gauge on the second part of the storm late Wednesday morning through Thursday morning.

If you are currently in the Winter Storm Watch (please know your county because I cannot answer the question if I am in a Watch or am I not in the Watch, that will be on you to know) 4-8 inches are possible.  Why the watch?  Because a north shift of just 10 or 20 miles can bring a marked increase in snowfall, but right now these areas are right on the line between light snow and moderate snow.

Now in the warning area there are three main focal points.  First, the snow potential.  If you are in the northern sections of the Winter Storm Warning area 3 to as much as 8 inches of snow can be expected.  The is primarily from a Lawrenceburg, Indiana to McConnelsville, Ohio line.  This is where sleet and snow will be moderate at times, but away from the heaviest returns.

The central zone is where the heaviest snowfall and sleet should fall.  In these areas, as little as 6 to as much as 12 inches can fall.  So places running along a line from Elizabethtown to Lexington, KY  on the south side and a Madison, Indiana to Chillicothe, Ohio on the north side can expect these amounts.

The third and farther south and east zone which is closer to the low and thus warmer air aloft for a time can receive as little as 5 but to as much as 10 inches of snow, mixed with periods of heavy sleet.

Small adjustments are going to continue but that is where things stand from my vantage point at this moment.

 

New NAM In, Quick Update with Newest Data

#Ice #Rain #Warm #Front #Low #Cold #Snow #Wednesday

A fast update on the 12 KM NAM:

Freezing Rain Depiction 1 PM:

00ZNAm18

At 1 PM still has ice potential around Dayton and Columbus…later in the day than earlier forecast.  A sign that cold air near the ground holds longer the farther north one goes?

Rainfall Tuesday Afternoon/Evening:

00ZNAMTuesNight

Regardless if the warmth lags, rain will overtake most, if not all, of the region by early evening.  As the cold front comes through late Tuesday night into Wednesday morning rain could become heavy and lead to potential flooding in the favored spots.   One key ingredient I have noticed with the NAM is how it appears that the precipitation stalls.  This might be the key to how a more northern track of the low happens behind the front for Wednesday afternoon and evening.  Why?

Wednesday Afternoon Snow:

00ZNamWedLow

The elongated area of low pressure seems to be tracking up the western spine of the Appalachians.  If, and yes it is a big if, it does track up the western side of the mountain region it will allow heavy snowfall for areas in Kentucky, southern Indiana, southern Ohio, western Pennsylvania, and western West Virginia.  Anytime you through rich, tropically enhanced moisture over a cold front into a rapidly cooling atmosphere thumping snowfall can result.

Snowfall Totals through Thursday PM:

00ZNAMSnow

Most areas from far southeastern Missouri, southern Illinois, the western two-thirds of Kentucky, southern Indiana, southern Ohio, into Pennsylvania and West Virginia could receive greater than 6 inches of snow, with some areas flirting with a foot-plus.  When the 18Z came out, I cautioned that it probably is overdoing it to a bit but with the new sounding data for the 00Z and showing a similar amount the ante rises a bit.

Remember this is only one model, the NAM, but I wanted to get the latest out for some that need to go to bed before its too late and wanted to share the newest information.

Monday Afternoon Update for Tuesday Storm, Wednesday Ideas

#Ice #Rain #Timing #Tuesday #Snow #Significant #Questions #Wednesday

A busy, high volume weather pattern is coming together over the next 3 days.  While today has been quiet, it will be anything but that from late tonight through midday Thursday.  First things first…

Tuesday:

TuesdayFreezingRain

Temperatures will fall tonight back into the middle teens to middle 20s as moisture races in from the Plains and Midwest.  The huge issue is the duration and amount of sleet/freezing rain that occurs before it changes to plain rain.  Temperatures, I believe, are running warmer too fast for certain areas.  This could allow for moderate icing to occur for certain areas.

(Advisory Map:  Purple-Winter Weather Advisory  Lavender: Freezing Rain Advisory  Dark Green: Flood Watch  Blue: Winter Storm Watch)

ILNFASTGRID

 

A plethora of weather conditions are now in effect for the region.  Wilmington, Indianapolis, Louisville, Jackson, Charleston, and Pittsburgh NWS offices will be burning the midnight oil over the next 72 hours.   So what do I feel will be occurring:

Sleet/Freezing Rain/Snow:

A brief edge of snow could fall before 850 mb (5000 feet) temperatures quickly rise above freezing.  The hard part is determining when the 925 mb (2500 feet) temperatures and the 1000 mb (ground level) temperatures rise above freezing.  The entire column of air will rise above freezing by mid afternoon for nearly everyone.  Question is how long will this process take?  That will be determined by a now-cast scenario.  Bottom line here is that icing will likely occur for almost everyone for a brief time in the south and southeast but increase in during the farther north and northwest one goes.  This will cause a myriad of issues because small amounts of ice will be very dangerous and light to moderate icing can cause strong and potentially damaging impacts.  It will be responsible for you, the individual, to be prepared for this event.

Rain/Flooding:

RAINTUES

As early as mid morning rain will fall for places in the south and west and become moderate to heavy at times.   The rain will gradually spread north and east throughout the day, so by early afternoon most areas along and south of Interstate 70 will be all rain.  Then as the afternoon progresses, the gradual changeover to rain will occur.  Period of moderate to heavy rain will likely lead to some low land and poor drainage area flooding.  Also, if you live near creeks, rivers, and streams be on high alert.  Ice jams, frozen water, and frozen ground will lead to some ponding of water and flooding situations.   A lot of this will come down to the structure of the storm and how heavy the rain will be.  With 1 to 2 inches of rainfall in areas, Flood Watches being out is the right call.

RAINFALL

 

 

Temperatures:

TEMPS

Highs on Tuesday will likely vary over short distances.  I believe that the northern extent of warming is too dramatic, but places to the south and southeast could easily rise into the lower and middle 50s.  Warm air advection is going to be strong and once the warm front clears a given location temperatures can rise as much as 10-15 degrees in just a few hours.  It is quite possible for Cincinnati to be 50 degrees while Dayton is 35.  As you can see on the map, lower and middle 30s in west-central and central Ohio with lower to middle 50s in northern and central Kentucky.  It is the gradient that will allow for heavy precipitation to fall for periods tomorrow.

Wednesday Afternoon/Thursday Morning Snowstorm:

12Z NAM:

NAM12Z

 

18Z NAM:

NAM18Z

So that is all right?  Not even close…. A very complex situation is going to occur between cold frontal passage Wednesday morning and  a southern wave that comes up late Wednesday evening into Thursday morning.  Models are all over the place and until the storm on Tuesday is set in stone, Wednesday’s storm will be hard to figure out.  A few models show tremendous thumping while others show gentler snowfall.  What has me on higher alert is the fact that a warm surge is coming tomorrow that will allow the low to travel up the temperature gradient.  Often times, the front slows down and allows the low to track more northwest than perceived.  This is what can bring southern Indiana, southern Ohio, Kentucky and parts of West Virginia into a heavy snowfall situation.  The issue here remains what is the Tuesday storm going to bring and how will that affect everything for Wednesday?  Time will tell, but with the Arctic air mass retreating, even if only for 24-36 hours, the baroclinic processes will be working to find the path of least resistance and may aid in a bit of a northward jaunt in the track of the low.

A lot to digest in a brief period of time that is for sure.

One Storm Gone, Who is Ready for the Next?

#Cold #Monday #Warming #Ice #Rain #Tuesday #Snow #Wednesday

The storm for late Saturday evening into Sunday afternoon has exited.  Nothing is ever perfect in a snow event, but another high skilled forecast verified quite nicely despite the doubt and impatience up through as late as early Sunday morning.  I would say that I was about 15-20 miles too far south with the snow/sleet/rain line but worth the margin of error.

(Monday Surface Map)

MondaySurface

We have a brief lull for Monday with colder temperatures and partly to mostly sunny skies.  Temperatures will bottom out in the lower to middle teens tonight, then rise into the lower to upper 20s on Monday.  That is about as long as the break lasts because another storm will impact the region by late Monday evening into the day on Tuesday.

TuesdayMorning

This is going to be another tough forecast.   Lows Monday night will drop into the middle teens to around 20.  However, low pressure will quickly develop and spawn a warm front over the central Plains and Midwest and race its way into the area by early Tuesday morning.  With the strong warm air advection aloft combined with sub freezing temperatures and snow at the surface, a long duration of freezing rain will be possible late Monday night into Tuesday morning in the southwest and then spread northeast overtime to affect other parts of the region Tuesday morning into early afternoon.

(Freezing Rain Tuesday)

TuesdayFreezingRain

An issue that will have to be addressed once again, are models overdoing the warm air?  This time it is a fool’s gold equation.  Yes, I believe they are rushing the cold air at the surface out too quickly, but it is going to warm above freezing and rain.  This is where things can get very tricky.  If the cold air holds on, for say 3 to 4 hours longer, then some areas could get significant icing.  We all think the snow/ice line is tough, try pinpointing the ice/rain line.  With temperatures just 1500-2000 feet above the surface likely to warm quickly into the upper 30s to lower 40s, that last 1000 feet could be a nightmare to time out correctly.  If this storm is subtly weaker and takes a subtly farther track south, then areas could stay ice much longer than anticipated.  It is very tough to know what it will do so check back Monday for updates.  Needless to say, another trying time for the area is coming up.

Once the cold front moves through, colder air will surge back into the area for Wednesday afternoon into evening.  Here is what I want the audience to do for me over the next 36-48 hours.  Follow local media outlets and other weather sources closely.  Feel free to post what they say over the next 2 days, Monday and Tuesday.  The reason why will be revealed at the appropriate time, because after the recent debacle of storms I want to see if they learned their lesson or it is out of sight out of mind and things return to the same old ways.  I do not watch media weather but I want to see how they see things before, during, and then right up to the storm.  Will be interesting to get the feedback.

Stay tuned because this pattern continues to be full of surprises.

Latest Update For Snow Storm and Totals

#Snow #Mix #Rain #Ohio #Indiana #Kentucky #Accumulations

OhioAdvi

I do not have much to really add at this point in the game.  My countless posts, updates, and audio suggests that outside of southern Ohio it will be mostly snow.  A mix of snow and ice will fall possibly as far north as the southern suburbs of Dayton and Columbus and then potential for rain in far southern Ohio.  I am encouraged from the update just over an hour ago that NWS Wilmington has taken out mix to rain in their update of the Winter Weather Advisory for the northern areas.  I feel that is appropriate.  Once into far southern Ohio into south-central and southeast Ohio rain can mix in at times, along with some icing.   So at this point, not a great deal of differences are found.

For Accumulation, 1 to 4 inches will likely occur in far southern Indiana and into northern Kentucky up into far southern Ohio.  Let’s use a Vincennes, Indiana to Madison, Indiana to WIlliamstown, KY to Portsmouth, OH to Kenna, West Virginia on the south side.   Here is where some mixing and plain rain can fall, especially on the eastern side of this line.  This can limit accumulations, but snow could accumulate an inch or so before rain and mixing issues occur.

3-6 inches will likely run from Sullivan, Indiana to Greensburg, Indiana to Middletown, Ohio to Circleville, Ohio to Caldwell, Ohio to Moundsville, West Virginia on the south side.  Quite reference point is where the south side of one total runs is the northern boundary of the first line of accumulation.  Hope that does not confuse, but it might.

A band of more that 6 inches will be possible in hit and miss fashion along and biased north of Interstate 70 in Indiana and into Ohio.  The confidence is not high enough to but a definitive line, but there is enough potential that a few pockets of greater than 6 inches can fall in these areas.

This 3-6 inch line extends far north into north-central and northern Indiana across into Ohio and over into Pennsylvania.

It pretty much is now time to sit back and watch to see how this storm ultimately unfolds.

Winter Weather Advisory Out, Continued Cold Trend

#WinterWeatherADVISORY #Snow #Ohio #Indiana #Accumulation

(Winter Weather Advisory in Purple)

WWASat

 

 

3 to 5 inches of snow in the northern tier counties and 1 to 3 inches of snow in the southern tier counties as of right now.

This is what is being said as of right now and personally, as I discusses last evening in the lengthy audio cast, I have my reservations on certain aspects.  A colleague, Dan, over at Dayton Weather Spot summed it up nicely in a post he made about an hour ago….I will share it here with you.

“Saturday, 2/28/15 9:10AM: NOTE: THIS MAP MAY BE REVISED LATER TODAY AS NECESSARY IF NEW INFORMATION NEEDS TO BE ASSIMILATED. …Okay, let me just say it. I’m sick of reading about forecasts containing the word “rain” for tonight/tomorrow’s storm. I don’t see it.

As you cut through the layers of the atmosphere, all you find right now around here is “freezing cold,” top to bottom. I’ve been known to call cold air a “bully,” because it is heavier and thicker than warm air, and it typically needs to be driven away by winds from the south or southwest…or by some huge storm from the southwest that can draw up a ton of warm air from the Gulf of Mexico in front of it. Right now, the jet stream is from the west (where there is equally-cold air), the storm firing up is far from a “Goliath” that should draw up a lot of its own heat from the south, and I currently have 12° west of Dayton. There is a lot of snow on the ground that should reflect most of the sun’s warming rays back out into space. Even direct sunshine hasn’t been exactly “cooking” us lately.

If warm air is going to move into the area to turn tonight’s and tomorrow’s would-be snow into rain, I’d like to know exactly where it’s coming from, because even the warmest of models are showing maybe a little sleet at worst in our south. No rain. I see nothing to indicate rain or any widespread ice north of I-71 tonight or tomorrow. As a rule, temperatures aloft should be cold with this system, so what starts out as a snowflake in the clouds and falls through freezing air has every reason to end up a snowflake on the ground. I still see snow. That’s what I’ve seen all week.

I’m just going to “go there” already. I don’t expect this system to have much rain or ice for anybody NW of I-71 (note, I did NOT say I-70!) on Sunday. This should be a snow-maker for our area. This storm is also likely to be just a tad weaker than the one last week…with most, on average, seeing maybe an inch less snow than the last one. Is it possible Dayton will see rain and 35° tomorrow? Yes. Is it likely? I don’t think so. I think 32° and snow is a more realistic picture based on the fact that I see nothing coming that could depose enough cold air to reach that high of a temperature. So instead of “snow turning to rain” on Sunday, I see “all snow.”

The exact path and nature of this storm is still under watch, because even a change of 25 miles can mean a world of difference between rain and snow. Our entire area is currently under a NOAA Winter Weather Advisory for the forthcoming snow, but I believe that they are underestimating snowfall and overestimating rainfall for Sunday. If they begin to share my sentiments of “3-7 inches,” (as opposed to the “2-4 inches” they are currently calling for) I would also expect to see their current advisory upgraded to a winter storm warning later today–particularly for Butler, Warren, and Clinton counties where the warning criteria is lower. That remains to be seen. …So for now, don’t be warned that there is likely moderate to heavy snow coming tonight and tomorrow, merely be advised of it. [Dan]”

There is no need for me to say anything else.  I will do the audio now and pretty much say the same thing I have been saying the last 2 days.

Detailed Audio Discussion on Thoughts for Sunday’s Storm

#Snow #Rain #Mix #Models #Ohio #Indiana #Kentucky #Battle

I know not everyone can get the Audio and if that is the case, I apologize but I am more-or-less going to give an Audio Play-by-Play of the modeling and see if this helps you see what I see better.

Feel free to give your input but I will post models and discuss them at length.

NAM: (500 mb Vort, 850 mb T, Surface T, Surface Reflection)

NAM500WIND

NAMNORTH

 

NAMTEMP

 

NAMSURFACE

GFS: (500 mb Vort, 850 mb T, Surface T, Surface Reflection)

GFS500Sat GFS850Sat

GFSSurfTemp00Z

 

GFSSurfaceSat00Z

CANADIAN: (500 mb Vort, 850 mb T, Surface T, Surface Reflection)

CAN500Sat00Z CAN850Sat00Z CANSurface00Z CANSurfReflection00Z

 

 

Time to Start Narrowing Down the Sunday Storm

#Sunday #Snow #Mix #Rain #Temperatures #OhioValley

Friday is now upon us and this is the day that you all have been waiting for as I try to start narrowing down the specifics with this storm for Sunday.  Numbers are not able to be reached; however, some of the general meteorology can start to be discussed to help the audience know what to expect.

First is the general trend of the major models that are used: the GFS, Canadian, European, and the NAM.  What are some of the key components that I am focusing on?  As per last week’s storm, the American models continue to be warmer than the foreign models.  The subtle hint is that at this point in time, they are a touch cooler than last week’s storm.  Lower to middle 30s make it into central and southern Ohio and southern Indiana for a time before cooling back below freezing.  At the same time, the 850 mb temperate at 5000 feet never get above freezing besides extreme southern Ohio and far southern Indiana.  Last week, these levels were indicating warmth into central Indiana and central Ohio.  So a bit cooler than the storm we saw last Saturday.

(850 mb temperatures from the NAM, GFS, Canadian from 00Z and Euro from 12z)

NAM:

NAM850

GFS:

GFS850

CANADIAN:

CAN850

EUROPEAN:

EURO850

When I take a look at the foreign model, the one key thing that stands out is how the European and Canadian dipped a bit farther south and has not budged north.  The latest European will be out in an hour so that will have to wait for further examination later, but the Canadian went south a few runs ago and has not budged northward.  Air temperatures fail to reach above freezing except for extreme southern and southeast Ohio  and extreme southern Indiana, while the 850 mb freezing line does not get any closer than a Louisville to Lexington to south of Huntington, West Virginia line.  The European was a tad farther north, but still south of the American model regime.

When I base this interpretation at 500 mb projecting a predominant westerly component, seeing 850 mb temperatures set up a shade south of last Saturday’s snowstorm, and noticing that apparent air temperatures are a touch cooler then where we were at this time in respect to the storm, odds are increasing that this will once again be a primarily snow event for places north of the US 50 corridor.  I caution, though, to allow a 50 mile error at this time.  This pretty much brings up that standard Interstate 70 measuring stick. With sun angle a bit higher then last week a little more warm component could become an issue for areas right on the line, but these are the fine specifics that have to wait until it is go time on Saturday evening.

Another critical period is coming up, so check back for updates later on Friday and Saturday.

Weak Disturbance Tonight, Stronger System Thursday, End of Weekend Threat

#LightSnow #Break #MoreSnow #Cold #Weekend #Storm #Battle

(Thursday’s System)

THURSNOW

A weak system will track across the area tonight into the morning hours of Wednesday with a few snow showers or flurries.  Little to no accumulation is anticipated.  The next system will drop out of the northwest Thursday morning into the afternoon.  This system will have a bit more energy and could drop an inch or two of snow between morning rush and the end of lunch hour.  That might create some issues because behind Thursday’s system a new batch of fresh Arctic air will come down and put us back deep in the freezer for Thursday evening through Saturday morning.

(Sunday Evening)

SundayEvening

Right here lies the important factor in determining the track and precipitation type for the weekend into early next week.  With the fresh, renewed cold air, a big high to the north and northwest of the system, it is likely the storm track will take on a more easterly component and not cut northward to warm the region up.  Modeling has trended colder and I believe it will do so once the energy is out of the way.

(Southern Storm System from Texas to southern Virginia)

USWARNS

Another caveat that can impact that storm is the system that will deal parts of Texas, northern Gulf Coast states, the Tennessee Valley into the Carolinas a serious bout of ice and snow.  Having snow laid down and tapping into some Arctic cold, as well, will only help to enhance the cold dominance over the eastern half of the United States.  All this energy has to get out of the way before the questions can be answered for the weekend, but it appears the deck is stacked for another cold solution and another snowstorm for the region to open up the month of March.

Tune in Daily for A Detailed Forecast for the Whitewater Valley of Indiana and the Miami Valley of Ohio. When you need a forecast here, now, and right now