A rain/snow mix is likely by mid to late afternoon in the Tri-State as a cold front approaches from the west. Through late morning, the only nearby reports of rain or snow reaching the ground have been in southwestern Indiana and western Kentucky. Dry air near the ground is winning for now, but there will likely be some light rain and snow in the area by 4pm, as the latest run of Microcast shows (snow is in blue, rain is in green):

Temperatures will drop only a couple of degrees tonight. In Cincinnati, we should drop to 29° by early Tuesday morning…just cold enough for snow. Notice Microcast forecasting snow showers around 7am tomorrow:

Snow will be diminishing tomorrow afternoon and may briefly mix with rain as temperatures crawl back into the low and mid 30s. Microcast paints a light rain/snow mix in the Ohio Valley at 4pm tomorrow:

Microcast gives us about 1″ of storm total snowfall accumulation through tomorrow night, and last night’s hi-resolution ECMWF gives us about the same:

Other models – including the last two runs of the NAM and GFS – give us 1″ or less. Unless a big change happens in the models, you can plan on around 1″ or less for the entire event; isolated amounts more than 1″ are possible tomorrow, but no community is favored to see 1″+ over another.

If the cold has been too much for you recently, think back to this summer when we had several days over 95° and a few over 100°. When you balance this year’s cold and warmth, the warmth clearly won out. 2012 will likely finish as the 4th warmest year on record in Cincinnati (records date back to 1871) and the warmest year on record at the Cincinnati/Northern Kentucky Airport (official records for Cincinnati began there in 1947). Here are the warmest years in Cincinnati:

It is worth noting that Cincinnati records from 1870 to 1915 – including in 1881, 1882, and 1898 – were taken downtown at the first local National Weather Service forecast office. These records are likely skewed warm due to Cincinnati’s urban heat island. While it is difficult to confirm, 2012 would likely be the warmest year on record if Cincinnati’s records were taken in the same location since 1870 (unfortunately, this is not the case).

Happy New Year!

From October 2011 to April 2012, 5.6″ of snow fell in Cincinnati. Contrast that with the 7.4″ of snow that has fallen in Cincinnati over the last 10 days. In Cincinnati, more snow has fallen in the last 10 days than in the 635 days before them (6.5″ fell between 3/27/2011 and 12/20/2012).

With Friday and Saturday’s event, there were large differences in storm total snow accumulations from one community to the other. Here is a map of storm reports from the National Weather Forecast Office in Wilmington (not all of the amounts shown are storm totals):

Notice the variation on snowfall amounts in and around the I-275 loop; I measured 1.9″ of new snow at the WKRC-TV studios in Mt. Auburn through 9:45am Saturday, but most within 10 miles saw 2-4″:

I assure you my total (through 9:45am) is correct; I am a trained weather spotter…and a meteorologist!

Unlike Wednesday’s event where there were fairly uniform bands of 1-2″, 2-4″, etc., snowfall amounts with Friday and Saturday’s event resembled a shotgun spray where some got blasted and others didn’t see as much. Snow banding was the main driver behind the variation in totals. Most of the fresh snowpack in the Ohio Valley can be seen on late morning visible satellite imagery:

Today will be sunny to mostly sunny with high temperatures in the upper 20s.

Another round of rain and snow is coming late Monday, Tuesday, and Tuesday night. The best chance for rain – be it small – will be favored south of Cincinnati tomorrow afternoon and evening. Most will just see snow from late tomorrow afternoon through Tuesday night.

How much snow is coming? Odds of 1″+ of snow from Monday afternoon through Tuesday night look good. Totals beyond that are uncertain. The latest NAM model runs paints 1-2″ of snow for the entire event, the latest GFS paints about 1″ (some community with less), and last night’s ECMWF model run paints 1-2″ of snow for most. This is raw model output, not a forecast. Forecast totals may be released as soon as tonight.

Yesterday afternoon, models suggested 1-2″ of snow would accumulate in the Tri-State tonight through Saturday afternoon. The newest model data is more aggressive with the chance for snow, so forecast snow amounts have gone up.

Recent SREF model runs have shifted heavier snowfall amounts north overnight, and have also increased totals. The risk for 1″+  of snow from 10pm to 10pm tonight is on the left; the 4″+ chance is on the right:

Notice a rather high chance for 1″+ in and around Cincinnati in this time period, but a low chance for 4″+. This is the main reason why I am not including 4″+ totals in my forecast for now. An isolated 3.5″ to 4″ amount is possible in our area, but it is not likely at this point.

The latest high-resolution ECMWF model shows generally 2-3″ of snow in the greater Cincinnati area tonight through tomorrow night:

These totals look realistic with the exception of the far southern Tri-State, where most models have lower snow amounts.

The National Weather Service has issued a Winter Weather Advisory for all but Mason County, Kentucky from 7pm tonight through 1pm tomorrow:

My latest snow forecast calls for 2-3″ for most in the Tri-State tonight through tomorrow afternoon; 1-2″ totals will be confined to parts of Owen, Mason, Robertson, Grant, Bracken, Adams, Brown, and Pendleton County:

Forecast totals will likely change later today; look for updates this afternoon and evening!

It will be cloudy tonight, but no rain, sleet, freezing rain, or snow is forecast until late tomorrow afternoon at the earliest. The latest model guidance continues to have accumulating in the Tri-State this weekend, but this will be a much weaker disturbance than the one that come through Wednesday.

Because this disturbance will be much weaker, snowfall totals will likely be much lower. Before we see accumulating snow, there will be a mix of light rain and snow Friday evening. The latest SREF model shows this mix of rain and snow around 10pm Friday; notice the rain winning out tomorrow evening:

By 7am Saturday, however, the SREF model shows mostly snow in the Cincinnati area:

This is likely going to be accumulating snow with temperatures in the upper 20s and lower 30s early Saturday morning. How much? The SREF has a 30-50% chance in the Tri-State (depending on where you live) for 1″+ of snow between 7pm Friday and 7am Sunday:

While this is NOT a forecast, the 7am run of high-resolution ECMWF model is rather aggressive with the threat of accumulating snow Friday night and Saturday:

Again, this is raw model data and not a forecast. These numbers appear to be a bit high, but isolated amounts up to 1.5-2″ appear possible with this system. These numbers are preliminary; adjustments are likely in the next 24-36 hours. I would rather ramp totals up than ramp them down. There will likely be some variations in snowfall totals from one Tri-State community to another.

We will release a snowfall forecast in the next 24 hours…stay tuned.

A large winter storm is on the way to the Ohio Valley later tonight and tomorrow. Like many storms in the Ohio Valley (especially where rain and ice mix in), snowfall totals are going to be tricky. There is fairly high confidence that the heaviest snowfall totals are going to be focused north and west of Cincinnati. Lower totals (where light freezing rain and rain will be found much of tonight and tomorrow) will be along and south of I-71. There is still great uncertainty in snowfall amounts along I-71. Some counties may see a 3-6″ spread from the highest snowfall total to the lowest total in the county.

A Blizzard WARNING is in effect from 1am tonight through 1am Thursday for Fayette, Union, Franklin, Butler, and Ripley County. Many in this area can expect frequent gusts up to 35-40mph, blowing and drifting snow, and visibilities under 1/4 due to blowing and drifting snow late tonight and Wednesday:

A Blizzard Warning does not mean 2′ of snow; it is issued when a combination of winds and low visibility make it difficult to travel. I strong discourage travel in this warned area late tonight and tomorrow. Sustained blizzard or blizzard-like conditions are not expected at this time in the Cincinnati metro.

A Winter Storm WARNING is in effect from 1am tonight through 1am Thursday for Warren and Clinton County. These areas are likely to see gusty winds, bursts of heavy snow, and wind chills in the mid teens to lower 20s overnight and tomorrow. 4-6″ of snowfall accumulation (with isolated higher amounts) are forecast in the northern half of the warned area:

Lower snow amounts are forecast closer to the Ohio River, where a Winter Weather Advisory is in effect from 1am tonight through 1am Thursday:

Notice there are areas south of this advisory not under any sort of alert. Only 1″ or less of snow is forecast in these areas, mainly due to the amount of freezing rain and rain mixing with snow. In fact, sections of northern Kentucky may see rain for most of the night and Wednesday before changing over to snow.

The most severe winter weather will be northwest of Cincinnati tonight through tomorrow night. Less snow and lighter winds will be found along and south of I-71, especially from Owenton to West Union.

For now, here is what I expect for snowfall amounts:

Notice the differences in snow totals, especially in counties along I-71. If this forecast verifies, northwestern Hamilton County will see 4-6″ (with isolated higher amounts) and southeastern Hamilton County will see 1-2″. These forecast snowfall amounts may change later tonight and tomorrow, and there may be isolated higher or lower amounts outside of each snow band.

Do you need any outline of when things are going to happen? There’s a lot to take in; I understand! Expect snow northwest of Cincinnati, rain and freezing rain southeast of Cincinnati, and a mix of rain, snow, and freezing rain along I-71 and in Cincinnati to change over to mostly snow by late tomorrow afternoon. Even at 4pm tomorrow, there will still be many with little or no snow accumulation (and just rain and/or flurries) well southeast of downtown:

Stay tuned; we will update the forecast as needed!

Computer models continue to suggest a large winter storm will soon develop in the Ohio Valley. Outside of very light drizzle or mist tonight, no precipitation is expected until Tuesday evening at the earliest. Near and after midnight Wednesday, rain and snow will overspread the Tri-State. Most northwest of Cincinnati will see all snow (or little rain) very early Wednesday morning, but the rest of the Tri-State will see a mix of snow and rain. Through Wednesday morning and afternoon, cold air will wrap in behind low pressure, and accumulating snow will overspread southwestern Ohio, northern Kentucky, and the rest of southeastern Indiana.

Based on recent model trends, the threat for seeing a winter storm in the Tri-State has gone up slightly:

The SREF model (which is really a blend of models) suggest 1″+ is likely for much of the Tri-State between 4am and 4pm Wednesday. It also suggests significant chances for 4″+ and even 8″+ of snow in central Indiana, including the northwestern part of the Tri-State:

Just after 4pm this afternoon, the National Weather Service in Wilmington issued a Winter Storm WATCH for Fayette, Union, Franklin, Butler, and Warren County:

This watch is in effect from 1am Wednesday to 1am Thursday. This watch may be expanded or Winter Storm Warnings and/or Winter Weather Advisories may be issued in the next 24 hours. Travel will be difficult at times Wednesday, especially during the afternoon and evening.

There is still great uncertainty on the exact timing, strength, and positioning of this system. The forecast will likely change as new model data comes in and once the storm forms.

There will likely be a WIDE spread in totals from Connersville to Maysville. Some models have a spread of over 12″ of snow between these two cities. This will be an abnormally difficult forecast, and it will be very difficult to pin down snowfall amounts for any given location especially with blowing snow.

Thank you for your patience while we continue to make an accurate forecast. Stay tuned…

A winter storm is still forecast to affect the Ohio, Tennessee, and Mississippi Valley Tuesday through Thursday, but there are large discrepancies on the exact timing, positioning, and strength of this system. This is not unusual this far out. We are entering a time period where longer range models will wobble from one solution to the next and shorter range models are just now getting up to speed on where this area of low pressure will go.

In the shorter term, there is fairly high confidence that light rain and freezing rain will develop in the Tri-State tonight. The latest SREF model run shows rain for most at 1am tonight and the potential for freezing rain north of the Ohio River:

As temperatures go above freezing tomorrow morning and afternoon, the threat for freezing rain will diminish. Rain, however, will begin mixing with freezing rain and snow Monday evening and early Tuesday. Notice the latest SREF model showing a blend of freezing rain, rain, and snow by 7am Tuesday morning:

While there is no strong agreement in the latest round of model data on the potential for ice accumulation Monday night and early Tuesday, this signal from the SREF model is telling. While few will be going to work Christmas Day, the threat for ice accumulation Monday night and Tuesday morning needs to be watched carefully.

The strong model agreement regarding accumulating snow Tuesday night through Thursday is not as strong today. Both the early morning GFS and NAM model give the Cincinnati area little to no snow, but the ECMWF model remains consistent with it’s solution of heavy snow for much of Ohio, Kentucky, and Indiana. The latest outlook from NOAA’s Hydrometeorological Prediction Center shows the potential for 4″+ of snow from 7am Tuesday to 7am Wednesday west of Cincinnati:

Given the uncertainty in the latest model runs, no snowfall amounts will be released today, and totals and may not be released tomorrow. Releasing forecast snowfall totals too early just leads to empty promises; I would rather wait and issue a forecast with confidence than release it too early and mislead people.

Good afternoon! The flow off of Lake Michigan has been interrupted early this morning; this means early morning clouds are giving way to sun. While today will be quite sunny, high temperatures will only be in the low to mid 30s.

High pressure will relinquish control to low pressure Sunday. Clouds will overspread the Tri-State, and precipitation will begin developing in the afternoon. Precipitation will begin as rain Sunday afternoon and evening. The most recent SREF model run from this morning shows rain our area at 7pm Sunday night with the threat for freezing rain staying north of I-70:

With temperatures slowly falling through the 30s, freezing rain starts to become a possibility – especially north of Cincinnati – after midnight Monday. The latest SREF model run suggests rain is more likely south of the Ohio River at 7am Monday, while many north of Cincinnati will see ice mixing with rain:

Last night’s NAM model run is not impressed with the chance for ice accumulation north of Cincinnati early Monday morning, but last night’s GFS model run is. Note the potential for about a 0.1″ of ice in the northern Tri-State through 10am Monday morning:

Both rain and ice will be light Sunday afternoon through early Monday. An ice storm or heavy rain is not expected at this time. Even small amounts of ice, however, can lead to very slick roads and sidewalks.

This disturbance coming through early in the week will be weak, but it will help a second, larger disturbance form and move into the Ohio Valley Tuesday, Wednesday, and Thursday.

There are still some big positioning differences in the model data regarding this system. Note that this morning’s GFS model run has the center of low pressure over the Tri-State at 7am Wednesday morning, while last night’s ECMWF model run has the area of low pressure over Tennessee (Cincinnati is indicated as a white star):

Differences in the positioning of the system make a tremendous difference in what type of precipitation we will see, how heavy that precipitation we will be, and when we’ll see precipitation. A more southerly track tends to mean more snow for the Ohio Valley, but there’s more to it than that.

Last night’s GFS model run suggests more freezing rain Tuesday night and early Wednesday; a map of how much ice will accumulate according to the GFS from now through 7am Wednesday is attached:

While the exact placement of ice accumulation will likely change over the next few days,  it is worth noting accumulating ice will be a concern Tuesday night and Wednesday.

The most recent runs of the GFS and ECMWF models suggest accumulating snow is likely Wednesday and Thursday. Specific totals are unlikely to be released this weekend; we’ll have a better handle on amounts Monday and Tuesday.

Confidence is rising that a significant weather weather event – including snow, rain, and freezing rain – will unfold Tuesday, Wednesday, and Thursday in the Tri-State. Stay tuned!