Winter Storm Possibilities

Great news for snow lovers.  The latest GFS and NAM have been showing a major snowstorm over most of our area with heaviest snow totals remaining along and north of U.S. Highway 30.  The catch is that temperatures will be only marginal as of right now for heavy snowfall accumulations.  Models such as the NAM are forecasting temperatures around here to be in the mid 30's, while some models such as the ECMWF are forecasting much colder temperatures during the snowstorm (if there is a storm).  Prospects for a snowstorm have only shown up in many model runs just recently and have been rather consistent with the NAM and GFS models.  Right now, both the GFS and NAM are the farthest north of the computer models, causing them to bring in more of a mix of ice and snow before changing to all snow.  If temperatures are as warm as what the NAM and GFS are saying, then expect a wet heavy snow to fall from the sky.  At the other end of the spectrum, the ECMWF has an all snow event with much colder temperatures allowing for a fluffier snow.  Since all three of these are very similar with this storm, a consensus of the models would bring this area a mostly snow event next week, with some sleet or freezing rain/rain mixed in.  While the exact timing of the storm is still in question, my current thinking is that snow will begin Monday night, then continuing through Tuesday night, with some sleet and rain or freezing rain mixed in throughout the day, with lows Monday night in the upper 20's and lower 30's, and highs on Tuesday in the lower to mid 30's, and falling throughout the day.  The GFS is not really consistent with its snowfall totals between its runs, but the latest run is showing rather exciting snowfall amounts (or what I would consider exciting) with most areas seeing 2-4 inches of snow, and some areas possibly more.  As for the NAM, well it doesn't go out that far to be predicting snowfall totals for this event, but it is predicting snowfall amounts of 1-3 inches Monday night, with more on the way for Tuesday.  This could be a pretty significant event so stay tuned for further updates.
As for the Christmas Day forecast, well, expect highs in the mid to upper 30's (pretty warm for this time of year) under partly sunny skies as well.  Won't be the best christmas because of the no snow cover, but it will still be fun.  Have a Merry Christmas everyone!

This map of the ECMWF 00z run is showing a snow event for the area.  Green colors indicate high relative humidity in the upper atmosphere, showing us where precipitation is likely to fall and the map with the low pressure centers on it shows us the position of storm systems and the position of the rain/snow line.  That rain/snow is the 540 line on the map, and on this forecast, the rain/snow line is well south of the area, indicating that most of the area will see snow.

Forecast Update through Tomorrow

A couple of things I forgot to mention I will talk about in this post.  One thing is that a large portion of the atmosphere will be saturated tonight and tomorrow over most of the area.  This is because of continuing showers and drizzle throughout the night.  This will cause nearly widespread fog to form tomorrow morning, becoming dense in certain areas, especially in the open areas.  Dense fog will likely continue through the mid morning and late morning hours.  Another thing, in an earlier post, I stated that rain showers could end as a period of snow Thursday night.  This is looking less and less likely.  Right now, it looks like just a few flurries Thursday night, with LES (Lake Effect Snow) possible on Friday and Saturday.  This is the last update until tomorrow morning.  Have a good night.

White Christmas Forecast, and Continued Long-Range Update.

Unfortunately, I have bad news once again.  Chances are becoming slimmer for a white christmas.  I am very sorry to say this, as we close out December, most if not all meteorologists long-range forecasts were wrong for the month of December.  Currently, most of the United States will close the month out well above normal.  Initial forecasts way back in October were saying that because it would so cold in the Midwest this December, they were expecting below normal precipitation, but above normal snowfall.  As you can see, we had just the opposite.  Instead of cold temperatures and well below normal precipitation, like last December, temperatures will close out December three to five degrees above average for the month.  This overall warmth, has lead to a very low snowpack across the country.  In fact, it may be the lowest snowpack the United States has seen in December since 2006, with only 25.6% of the country covered with measurable snow.  Another opposite that was seen in December, was above normal precipitation.  So far this December, we have seen nearly 3 inches of precipitation, not near as much as November, but still far above normal.  Currently, we are about 1.5 inches above normal for December.  The above normal precipitation throughout the year, has lead to some pretty impressive anomalies (departure from normal).  Right now, 2011 is the third wettest year on record at Fort Wayne, with nearly fifty inches of rain (or snow) fallen.  For comparison, this is the normal amount that places such as Central Florida receive in one year, and we have had more rain than many places in Florida this year.  The exact total for this year is 48.73 inches, which is well above what last year's precipitation total was, which was 32.46 inches.  If long-range models and forecasts are correct, I expect well above normal precipitation to continue through at least the first seven months of next year also.
Now for the white christmas forecast, as the current storm system moves out, not much of a cool down will take place, with another storm system tomorrow, causing temperatures to remain in the upper 30's and lower 40's.  Actually, temperatures on Thursday will remain steady throughout the day, then dropping in the afternoon, into the lower 30's by nightfall.  With the next storm system, we could end with a period of snow Thursday night, as temperatures will be in the upper 20's, and the 540 line (5400 meter thickness between the 1000 millibar layer and the 500 millibar layer, usually indicating the rain/snow line) will be well south of the area, leading to a period of accumulating snow, especially east of Fort Wayne.  On Friday, temperatures will drop into the mid 30's under mostly to partly cloudy skies, as the next storm system from the Gulf of Mexico moves northeast into the East.  The problem is that, this storm was originally forecast to bring us some light snow on Saturday, which does not look likely anymore, as the storm will be too far to the east.  Temperatures also do not look as cold as it originally did.  By Christmas Day, a few snow showers will be scattered throughout the area bringing surprise white Christmas's to a few areas.  Highs that day will be in the lower 30's and possibly colder, even though the National Weather Service is forecasting temperatures in the mid to upper 30's, I do think that this arctic air mass will be cold, and even cold enough to produce lake-effect snow.  By next week, yet another warming trend, but not as much as the last warming trend (into the lower 40's and upper 30's), with some periodic arctic air masses moving into the area through New Year's Day.  By New Year's Day, a new set of storm systems will be affecting starting once again the pattern of heavy precipitation, and once again this is where the long-range gets tricky.
   Yesterday, I mentioned some of the tid bits in the long range.  I did never get to mention the ENSO, so here goes.  According to the latest climate forecast models, the La Nina will continue to strengthen, possibly becoming a strong La Nina around -1.7.  According to the CFS, CFSv2, and the GFDL, they expect the La Nina to peak in strength around March, even though their respective forecasts vary in intensity.  The CFS is forecasting a peak around -1.9, the CFSv2 around -1.4, and the GFDL around -1.8.  If you average these values, you get -1.7.  As for precipitation and temperature extremes, the models are all varying from each other, so it probably isn't that wise to treat these forecasts as truth.  The CFS is forecasting a rather warm January, for the area, while in February and March, temperatures drop well below normal, leading to a very snowy end to winter.  The CFSv2, is forecasting above normal temperatures through June, with only slightly below normal temperatures for February.  As for precipitation, almost all of the models agree that precipitation will be well above normal for the next five months, leading to continued flooding problems, and possibly severe weather problems in April and May.  With the strengthening of the La Nina, I expect that this forecast will hold true.  But as for the next month, I have looked at the teleconnections and this is my good news (for snow lovers that is).  The NAO is expected to gradually drop into negative territory, allowing all that extensive cold in Canada to drop southward finally.  At the same time, even though there is less agreement among models on what the AO will do, there is a general downward trend in its values also, becoming negative by about January 1st, and continuing its downward turn.  The PNA, at the same time, will become positive, which is conducive to a west coast ridge, and east coast trough.  All of these factors, if these forecasts are correct, will converge right around January 1st, possibly making January a very cold and snowy month around here.  All of these factors, combined with the La Nina, will cause a very interesting middle and end to winter.  Not only will these factors converge, but also, solar output will also be taking a dip, leading to colder temperatures and therefore snowier days, instead of rain.  All of this could have serious consequences in the spring, because I am expecting major flooding this spring, even more so than last year.  This is my update, for more updates, tomorrow I will try to have an update.

Long Range Update and White Christmas possibility.

This morning, many of you probably woke up surprised to see it snowing.  Last night, I said that thermal profiles could be marginal for a sleet/snow/freezing rain event.  Well, I was right, sort of.  It turns out, thermal profiles were cool enough to support all snow in quite a few areas south of U.S. 6.  In Antwerp, the precipitation was all snow until it changed to rain around the noon hours, accumulating over an inch.  As you can see, this snow did not stick very well, as most of it has melted in this afternoon's light rain/drizzle, even with temperatures near 34.  As for the forecast through Thursday, expect rain showers becoming more numerous tonight, as a low pressure system heads towards the area.  Rain and cloudy conditions will continue tomorrow, but with much warmer temperatures, nearing the upper 40's.  As is not surprising, this high will be well above normal, nearly 13 degrees above normal for this time of year.  Right now, I am really sick and tired of this rain and warmth.  I just want it to be cold and snowy like it was last year.  More than likely this won't happen until after this storm passes through.  Even with the passage of the cold front (or whatever's left of it), temperatures will drop but not as much as with a normal cold front.  I would expect by Thursday, temperatures will be rather mild, in the mid 40's but dropping quite rapidly throughout the night, into the mid or upper 20's.  Temperatures in the Friday and Saturday time period will be much closer to normal, around the mid 30's.  During this same time frame, we will have our last chance at a white christmas before the day itself.  At this time it will all depend on the track of a storm system from the Gulf of Mexico, which is currently indicated to track northeast along the East Coast by the ECMWF.  If the ECMWF comes to light, I would expect us to get the tail end of a huge snowstorm, with moderate snow possible.  If this were true, snowfall amounts will be in the range of 2-4 inches on Christmas Eve or Christmas Eve night.  After that, very cold air will enter the region and cause daytime highs on Christmas and Monday to be in the mid and upper 20's.  If the GFS's forecast would verify, snow will fall around here, but not nearly as much as what the ECMWF and DGEX are forecasting.  The GFS has a very progressive forecast, meaning that it is keeping snowfall to a minimum, because it moves storms very quickly across the United States.  I'm actually starting to side with the GFS forecast, mainly because of the teleconnections.  The NAO is in a positive regime and so is the AO, supporting the pattern of a warmer, more progressive weather pattern than what the ECMWF is indicating.  Either way its still going to get cold around here by Christmas, with details on how long it will last are not clear at this time.  According to the latest North Atlantic Oscillation ensemble forecasts, the NAO will be on a down turn, indicating that the long expected winter pattern will finally arrive by January.  It is really unclear at this time how and when that this pattern change will take place, but if the stratosphere will end up warming in the next couple of weeks, then this pattern change will likely take place by the very beginning of December.  Right now it looks like it might take a while, but I really do think the pattern change will come, leading to a very snowy and possibly cold January and February.  As for the La Nina influence, I have do have good news (for snow lovers that is!).  According to the monthly SOI values (Southern Oscilliation Index, a positive phase indicates a La Nina, negative phase indicates an El Nino), the La Nina has been steadily strengthening over the last several months, leading me to believe that even wetter conditions will become more prevalent in January and February, along with colder temperatures.  This is really good news.  But if the teleconnections do not support this, its going to take a lot before a major storm hits around here, so hopefully they cooperate. As for the rest of this winter into spring 2012, the latest CFSv2 model runs are showing very wet conditions throughout the entire Ohio Valley and Great Lakes through at least June.  This correlates rather well with the strengthening of the La Nina and the teleconnections.  The CFSv2 is also forecasting a near normal January (some of the ensembles are forecasting warmer than normal temperatures, but I think that if the teleconnections line up right, temperatures will actually be opposite of this.) So it could either way.  For February, it is forecasting below normal temperatures along with above normal temperatures causing above normal snowfall.  Stay tuned for further updates.

Another Forecast Update

Models last week at this time were showing a snowstorm over the area right about now.  Models four days were showing a mostly snow event with some rain and sleet.  Once again, models one or two days ago were showing a mix event.  Models yesterday were showing an all rain event for the area.  Today, models are showing a mix event for the area tonight through Tuesday night.  My take on this storm is that a cold front will move through tonight, causing temperatures to drop.  This will allow for a mix event by the very early morning hours of Tuesday morning, with sleet, freezing rain, and snow all possible.  As temperatures warm throughout the day, the wintry mix should give way to rain showers, and possibly heavier rain if the storm decides to take a farther northward track (which is not likely at this time.).  Therefore, I have lowered rainfall amounts from a half inch to an inch, to about a quarter of an inch for Tuesday, with some areas especially southeast of U.S. 24, picking up at the most a half inch.  Right now, with way the models are going, these rainfall amounts may still be a little high, but you never know.  By Tuesday night and Wednesday, temperatures will have warmed up enough to allow for all rain and more rain will move into the area.  By Wednesday, temperatures will likely rise into the mid and upper 40's, with some higher temperatures possible.  Wednesday will feature showers on the back side of the low, and maybe a switchover to snow if temperatures are cold enough.  For the rest of the week, periodic snow and/or rain showers will occur on a couple of other days.  This is where the forecast gets tricky once again.  Several computer models are once again trending toward a possible snowstorm over our area on Christmas Eve.  Some of these computer models are the ECMWF and the DGEX models.  The GFS is showing a storm moving quickly off shore of the East Coast, bringing in a very cold air mass for a large portion of the United States.  At this time, it is possible that see we a snow event on Christmas Eve, all depending on the timing of a storm moving from the Gulf of Mexico northward.  Right now, several models have been showing an east coast storm, but if the general trend of a westward and northward shift happens, then I would expect a major snowstorm over the area.  If this doesn't happen, expect a few lake-effect snow showers and temperatures falling into the lower 30's and upper 20's, which could bring a few areas a dusting of snow.  All of these are possibilities.  Stay tuned for further updates.

Bad News Once again.

According to the models I have seen this morning, it looks like we will probably see little or no snow during next week's storm.  In fact, precipitation amounts do not look that high at this time, as the heaviest precipitation will be situated to our south.  Tuesday will probably end up being our best shot for rain, with widespread rain moving into the area.  The heaviest rainfall amounts with this storm will be along and southeast of U.S. 24, with rainfall of 0.5 to an inch of rain.  This system does not look to be that big around here, so don't expect anything major.  But unlike the last storm, our temperatures during this storm will about 20 degrees cooler, allowing for the possibility of a mix of ice, snow, and rain at times Tuesday afternoon and evening.  We were originally expected a possible snowstorm next week, but now this does not seem near as likely.  One reason is because of the heavier precipitation shifting south of our area.  Second, there will not be enough cold air involved with this system.  This will keep much if any snow from forming.  Third, the storm system will be weakening as it heads northeastward, which will not allow a band of heavier precipitation (or snow) to form.  All of these factors, have made this storm not a snowstorm, but just a mediocre, rain and mix event.  After this storm, a major cold blast does not appear likely.  Right now, it looks like the cold air will gradually ease into the area, with cooler temperatures each day.  By Christmas Day, we may be seeing some snow showers and temperatures in the lower 30's and upper 20's.