White Christmas, a 50/50 chance.

As most of you remember, last December was one of our coldest on record, with temperatures below freezing for almost 90% of the month.  Temperatures last December hit rock bottom with several subzero nights and days that did not make it above 20 degrees.  We also had quite a bit of snow last December (even though we could have had more).  Even with a warm and rainy ending last year, temperatures still averaged nearly 6 degrees below normal for the entire month.  This year, we can't even to seem to get a nighttime low below freezing rather than a daytime high.  So far this December, temperatures have averaged 1.5 degrees above normal (it would be much higher if it weren't for those rare cold days.).  Another thing different from last December was snowfall and snow cover.  This year, only about 10-20% of the United States is covered by snow, while a year ago, nearly 60% of the United States.  This really does show how warm it has been since November.  There are two bad things that have been happening because of this warmth.  One, well above normal precipitation, creating major river flooding all over Northern Indiana and Ohio.  Two, this warm air has locked all of the cold air in Canada, and it has been building for several months.  If any kind of slight stratospheric warming occurs in the next several weeks, then expect all of this cold air to rush southward, enhancing the stratospheric warming process.  When this happens, that's when I expect the worst of winter to arrive.
    As for my white Christmas forecast, I expect that we do have a better chance than I thought a week ago.  The Monday/Wednesday storm of next week has shifted southward on most if not all computer models.  Current indications show a mix event with some periods of rain, changing over to all snow for a good chunk of Tuesday night.  This could mean several inches of snow depending on the track of the system.  If the storm tracks farther northward, and pulls in the cold air faster, expect heavier precipitation with higher snowfall totals.  If it tracks northward without pulling the cold air in faster, I would expect very heavy rainfall amounts, with widespread flooding possible by Wednesday.  If the storm decides to head south, expect a brief changeover to snow, with not as much precipitation as a result.  Current indications are that the ridge will once again become moderate in strength next week, allowing the storm to take a farther northward track (through southern Indiana and Ohio), but at the same time a major trough develops in the Midwest, helping to bring more cold air into the back side of the storm than during the last several storms.  This would be the scenario to bring a mix event with heavy rain, then rapidly falling temperatures causing a changeover to snow.  These all look to be a possibility by Tuesday.  If we end up not getting any snowfall Tuesday night, we have yet another chance on Friday.  According to the GFS and CMC models, a rather strong Alberta Clipper will move through possibly moving far enough south to tap into the Gulf of Mexico moisture, which could a major storm in the area.  If it does tap into enough moisture, and with the amount of cold air that the GFS and CMC are expecting in the area, I believe that this could a rather potent snowstorm.  Right now, it looks it will be snowing throughout the day Friday, with the possibility of a couple of inches of snow.  Whether or not this comes to fruition, I'm not sure, but one thing I do know is that more than likely very cold weather and cloudy weather will be in place Christmas Day, with the possibility of snow showers.  At this time, I think that indications show a pretty good chance of a white christmas, it just all depends on if that cold air in Canada decides to shift southward.  Stay tuned for further updates.

Alberta Clipper Saturday

It looks like now there could be an Alberta Clipper Saturday, bringing reinforced cold air, and some light snowfall accumulations.  Accumulations will run anywhere from a half an inch to an inch, with light snow Saturday afternoon and night.  Stay tuned for further updates.

Tuesday's Storm Potential

Right now, chances are again increasing for another heavy rainstorm for in our area in the Monday-Wednesday timeframe next week.  For some reason, the arctic air seems to be locked up in Alaska, Siberia, and extreme northern Canada, and will likely continue to be so through mid next week.  After that, everything gets a little fuzzy, especially around Christmas Day.  As for the medium range, next week's storm will more than likely be rain (sorry for you snow lovers, including myself).  This just has not been the December for major snow events.  The storm system will likely form from a cut off low ejecting from the Southwestern United States, into the Ohio and Great Lakes region.  According to the GFS and ECMWF, the storm will take a more southerly route than originally thought (Remember, originally the ECMWF was taking this storm way north of our area.).  The problem with these models is is that they are not showing any cold air north of this system, even it should be there.  So until the models come into agreement, we may not know exactly what will happen until Sunday or Monday.  It is a possibility that we do see a major snow event, especially in light of a good chunk of the models taking the storm system just to the south of our area, leaving us in the cooler, drier air.  This means we probably wont' rise much above the mid to upper 30's on Tuesday.  This might cause a wet and slushy ice storm across the area Tuesday morning.  This is not set in stone, and this may not come to light.  Right now, I think that the storm system will lift north, but the warm front will not pass through the area, keeping the area rainy and cold.  Rainfall amounts with this system will probably be closer to 1-3 inches once again, depending on precipitation type.  At this time, it looks like the rain/snow line will be located in extreme northern Indiana and Ohio, meaning a snowstorm for southern Michigan and northern parts of Indiana and Ohio (This includes everybody north of the Toll Road).  As always, if the storm would happen to shift southward, expect more snow across the entire area.  If the storm would happen to shift northward, expect very heavy rainfall amounts across the area.  As colder air rushes into the region by the end of the storm, a changeover to moderate or heavy snow is anticipated, causing at least minor accumulations.  As for my forecast for Christmas Eve and Christmas Day, I expect yet another system to move through, causing snow and wind, potentially accumulating from an Alberta Clipper, or possibly a stronger storm system.  Highs will more than likely be in the 20's on Christmas Day, as cold air finally arrives.  As soon as a new pattern sets up, cold air will finally set in.  This will likely happen in the last few days of December, or January, bringing the worst of winter in January and February.  Stay tuned for further updates.

Forecast Update

More model data has come in, and now it is almost certain (we can never be one hundred percent sure) that rain will fall with this system, in fact even heavily at times.  The latest radar maps have shown heavy rain bands moving in our direction from Illinois and Missouri.  You probably could tell that the storm system was moving closer, as we haven't seen any sun today, unlike yesterday.  The rain bands will continue to move closer to our area, and by late evening to around midnight, the rain will finally arrive and last through most of the night into Wednesday morning.  Here comes the tricky part.  It is still uncertain when the rain will end for a while tomorrow, or if it is going to end.  For right now, I expect a moderate steady rain overnight tonight, amounting to a quarter of an inch with some areas especially west of Fort Wayne, seeing more than a half an inch.  I think that the rain will end around 9 a.m. tomorrow, most likely south of a line from Marion to Van Wert, with areas from Fort Wayne to Antwerp and Toledo seeing light rain throughout the day.  Areas north and west of Fort Wayne, near South Bend, will likely see the rain last throughout much of the day.  In areas where the rain becomes lighter or tapers off, rain will move back into the area by Wednesday afternoon, becoming heavy at times with thunderstorms POSSIBLE.  Right now, I don't think there will be enough instability for much thunderstorm activity, so expect all rain, as a moist flow from the Gulf of Mexico flows straight into the storm.  This will allow for heavy rainfall totals Wednesday night into Thursday morning.  My current thinking is that entire rainfall totals will be near 1-3 inches especially north and west of U.S. Route 24, including Antwerp.  Areas south of this line, will see lesser amounts from 0.75 inches to 1.00 inches.  Any heavy rainfall that occurs Wednesday Night will cause flooding and possibly flash flooding, renewing any river flood threat that has since disappeared.  Thursday morning, rain will be exiting the area, with a pre-frontal squall line moving through the area, bringing showers and possibly a thunderstorm.  Very windy conditions will be possible Wednesday night during the heavy rain, with gusts up to 40 mph.  As the cold front moves through Thursday, temperatures will drop from the lower 50's in the morning, to the mid 30's by Thursday evening.  Temperatures from Friday to Monday will likely be in lower to mid 30's on some days, with possibly a warming trend to start next week off.  This the uncertain part.  The ECMWF is forecasting much colder temperatures along with its ensembles.  With this in mind, the last several runs of the ECMWF have trended slightly farther northward, bringing a very strong storm system right over our area by Monday and Tuesday.  Temperatures will probably be cooler than what the NWS is forecasting, with highs in the low to mid 30's, as clouds increase ahead of this strong storm system.  The ECMWF is showing sleet and freezing over most of the area, as the 540 line (thickness between different levels of the atmosphere, this line indicates where snow will likely fall), will be positioned right over us or just to the south, but with below freezing temperatures.  This means that warm air aloft will cause melting of the snow, but it will refreeze once it falls to earth.  This could mean a heavy sleet and freezing rain storm for the area by next Monday night and Tuesday, with all precipitation changing to heavy snow by Tuesday afternoon and evening.  Remember this storm is about a week off, so a lot things could change by then, hopefully for the better, more snow!  Another one of the computer models, the GFS, is forecasting the storm track to be quite a bit farther to the north, bringing heavy rain into the region and even heavier rainfall amounts than the current storm system.  The thing is is that the GFS has precipitation ending as heavy snow across the area by Tuesday afternoon, as temperatures drop rapidly from the lower 40's to the 20's.  As I said before, this whole forecast could change for the better or for the worse in the next couple of days so stay tuned for further updates.  One last thing I want to talk about is a white christmas.  Current indications are that we have about a 50/50 chance of having at least an inch of snow on the ground by Christmas, with everything depending on next week's storm.  If it is a snowstorm for the area, snow will probably stick through Christmas, assuming that temperatures do not warm during the rest of the week.  Current indications are saying that after next week's storm, no matter if it is rain, snow, or sleet, will cause temperatures to rapidly tumble, to below normal values.  If forecasts for the warming of the stratosphere over the arctic Christmas week are true, very cold weather will likely stick around for the rest of December and even January, finally becoming aligned with the winter forecast of below normal temperatures.  Hopefully this is what happens, because I am tired of seeing warmth and rain, I want it to snow!  Keep checking my blog for further updates as this situation progresses.

Not Just One but Two

After looking at most computer models, most of them still don't seem to be in agreement with this next storm system, which will, at this time, likely produce rain.  I really do think the GFS and the ECMWF are still too far north with this system, as they have been trending southward the last several runs.  Here's my current thinking on the next few days before the storm system hits.  Today, highs will be limited to middle thirties, or even colder in areas that have more snow cover, such as southern Michigan.  Lows tonight will fall into the lower and middle 20's, making for another frosty Monday morning.  Highs will warm even more Monday, as a large ridge builds in the East.  Temperatures will reach the upper 30's, if not lower 40's.  By Monday night, temperatures will not be allowed to cool as much even with the snow cover in some areas, as warm air advection takes place.  By Tuesday, thick clouds will move into the region, along with a weak upper level shortwave.  The air will still be too dry to allow this system to produce any considerable precipitation around here, but to the north and west (Chicago and northwest), precipitation will be likely.  Clouds will increase in coverage Tuesday night, as the next storm system approaches from the southwest.  Some computer models such as the GFS, have the system moving through faster, therefore producing less rain, but coming earlier.  Others, such as the ECMWF have the system moving more slowly and farther too the north.  At this time, I don't think that either of these solutions are correct.  I'm forecasting that the storm system will approach the area by Wednesday morning, bringing rain into the region by mid to late morning.  With how much moisture that will be associated with this system (even though the GFS and ECMWF aren't showing much), I expect rainfall totals to be heavy, possibly in excess of one or two inches.  This will really get flooding problems going again, with moderate flooding coming back to the Maumee river.  The system could end with snowfall, possibly 1-2 inches of it.  This would happen if the storm system would happen to take a more southerly route, bringing the cold air farther southward into the United States than what the GFS and ECMWF are forecasting.  I think that this system will take a more southerly route, mainly because I don't think the GFS has a good handle on the southwest cut-off low, and the fact that the ECMWF is almost always warm biased, causing it to bring storm systems to far to the north.  With the more southerly solution, expect heavy rainfall and flooding, possibly ending as moderate to heavy snow on Thursday night.  By Friday and Saturday, cold air causes temperatures to drop into the upper 20's, but not much colder mainly because the fast, progressive flow aloft will not allow the cold air to leave Canada.  By the end of the weekend into early next week, I really think that a new storm system will develop in the lower Mississippi Valley, tracking northeastward into the Ohio Valley.  This next system could be a major snowstorm for us, or even a rain event changing to heavy snow for 6-12 hours.  Either way, this next system could be the storm system that brings our first heavy snowfall of the season.  Continue checking my blog for further updates.