We’ve finally ended our streak of not hitting 40° for months but the weather certainly is no picnic with showers, clouds, and fog. But the snow is melting! I will try not to complain too much considering how we longed for this to happen back in February. So far many locations have already picked up a third to a half inch of rainfall, but we’re not done quite yet.

Rain Vision rain estimate:

There are multiple systems pushing in from the Pacific that will merge together into one stubborn, slow moving cut off low.

Notice the two storms:

Combining as one big cut-off low:

The storm is effectively cut off from the jetstream winds, so it won’t get booted east anytime soon. Our computer models are showing potential for rainfall to exceed an inch for parts of Iowa and Nebraska through Friday. Every one of the next four days will have periods of wet weather, but I expect the wettest this morning, and another round of moderate rain on Thursday as the system picks up intensity again. By the time we are done with this stretch of wet and above freezing weather, there will be numerous rivers with ice jamming and flooding as the deeper snowpack of MN and SD drains south and east into our area. HPC rainfall estimate for the coming days and through Friday morning:

Dave Winslow

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The streak of not hitting 40° here in Sioux City has finally ended.  Our new record of 96 straight days now sits atop the record book thanks to a high on Monday of 40° even.  As you can see below, our streak started way back on December 2nd.

Ron Demers

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We are entering my favorite time of year, Spring.  I love the warming temperatures and the transition from snow storms to thunderstorms.  We got our first thunderstorms for the year in Siouxland on Saturday evening.  A line of small thunderstorms developed just before 5:00 along I-29 south of Sioux City.  They weren’t all that impressive, but did have occasional lightning and even some small hail.  Here are a couple pictures taken by Daniel and Cheraine Bromander from Sloan, IA around 5:00 Saturday evening.

You can see the hail wasn’t very big, although there was one report of 0.50″ hail near Onawa.  But it is still a good sign that Spring truly is just around the corner.

Mike Zwier

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How many times on our blog were we talking about another winter storm or blizzard this winter? Well take that old man winter, it’s rain this time around! This system isn’t going to be tapping into any really juicy Gulf moisture or anything, but the upper levels of the atmosphere will be well above freezing leading to rain falling down into our snowpack and onto our streets and side walks. It is possible that a few spots for a few hours see a very tiny bit of freezing rain (primarily along the MN/IA and SD/MN border), but chances are that would be very light and by the time the heavier rain moves in we’ll all be above freezing. Timing-wise the best rain chance will move into Sioux City between 4 am -8 am…then we may see some lingering showers into the day. Can you really complain about 40’s and rain after seeing 4-5 blizzard/ground blizzards and 60″ of snow? Here’s a snapshot of our in-house computer model at 8 am tomorrow morning:

As far as rainfall is concerned, most of us will see a few tenths of an inch though this model tries to show a little more in spots (probably overdone):

This kind of rain won’t lead to an immediate flood, but it will be absorbed by our snowpack and eventually melt away with this prolonged spell of 40’s. There is a pretty decent chance that as melting continues into next week we see some ice jams and rising river levels in the tri-state area.

Dave Winslow

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I just wanted to pass along a couple pictures from Unity Elementary today where I talked to the 2nd graders.  Thanks so much for having me there today and being a great audience 2nd grade!!

Ron Demers

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I was at the Home Show over this past weekend and I met a woman who enjoyed the picture of two feet of snow and she really wanted to see it on our website if I could.  I told her to watch my blog and I’d try to remember to put it on here.  Well, Ihave remembered making me a man of my word.  This picture was sent to us by Larry Schmedding of Walthill, NE.  It’s a picture that was taken by his brother-in-law in New Hope, PA.

Ron Demers

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A flip has been switched to the “March meltdown” mode and it’s only going to get more spring-like by the weekend. We’ll break our stretch of 91+ days of not hitting 40° very soon indeed. About the spring-like systems that are aiming at the Upper Midwest….it still appears that the Pacific originating storm will arrive with warm air and just rain for late Friday night, perhaps not until early Saturday morning.

 Satellite and radar imagery this morning:

WRF QPF into Saturday evening:

 It doesn’t look like a ton of rain, but perhaps a few tenths of an inch. This model shows much more for Eastern Nebraska and Western Iowa, but I’d bet it’s overdone since the Gulf of Mexico will not open up until next week. This system will loose some momentum and weaken as it moves in Saturday morning. The more active weather pattern will reload with another larger storm coming off of the Pacific for early next week.

The GFS upper level flow forecast for Monday at 7 AM:

 It too will bring in warm and relatively moist air, and probably just rain for Monday and Tuesday. Our computer models are still a little uncertain with the timing and path of this storm, but it looks like no matter what it will be mild early next week and primarily a rain event. I will caution that it’s probably too early to completely wipe away a wet slushy snow chance on the tail end of the system, it is after all March. The rivers that have been iced up will probably transform quite a bit by the end of the weekend as ice jams and flooding will become more probable especially if rain ends up being significant.

David Winslow

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This winter has been one of those that has us setting some records and getting very close to other records.  Overall, we’ve had our 7th snowiest winter season so far.  All that snow has kept things cool and we’ve now tied the record for the most consecutive days with not hitting 40°.

Another streak was snapped on this first day of March becauseour snow depth went down to 9″.

The incredible thing about the above statistic is that if we hadn’t gone down to a snow depth of 9″ on Jan. 23 & 24, we would have seen 66 consecutive days of a 10″ snow depth that would have started on Christmas Day.  Here are the snow streaks that we still have going.

We’re not quite in the top 5 yet of 1″+ snow days but we will keep counting here at Storm Team 4 and keep you updated.

Ron Demers

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We have been hinting at the possibility of our pattern changing a bit for the month of March, but it won’t be much different until the end of this week. We’re still colder than average and only melting a little snow…but be careful what you wish for! By Thursday we should begin some accelerated melting as highs go into the upper 30’s, and we should be able to manage 40’s this weekend! That will be the first time since early December! This has been a record length of sub-40° days (we tie the record today at 90 days, break it tomorrow at 91 days).  An upper level ridge will be pushing into the Hudson Bay area of Canada which will effectively divert Arctic air into Northern Canada, not the Midwest for a change. This ridge will break down and a couple of pieces of energy will move in from the Pacific Ocean.

Upper level (jetstream) flow Friday afternoon:

The first will be on Friday and Friday night. It looks too warm for snow at this point (but something to monitor). The next system looks much much beefier for early next week.

This kind of storm is what March is known for, with a severe weather outbreak a possibility in the Southern Plains and deep south, and a big snowstorm or blizzard higher in the Northern Plains. It appears that we will see rain from this system first, and a possibility that the colder air will turn the rain over to snow early next week.

Monday morning at 6 am:

One of the big concerns if our computer models pan out and we see rain to accelerate the snowmelt will be some flooding. The hydrology department of the Sioux Falls National Weather Service has done some work to forecast the probability of spring flooding and here’s a quick excerpt:

 More can be found here if you’re in a flood prone area:

http://www.crh.noaa.gov/images/fsd/pdf/021910-flood_outlook_web-story.pdf

Please stay tuned to that website and KTIV as we cover the spring changes that always always cause some issues this time of year.

Dave Winslow

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I don’t think it’s just me when I say that morale has been down tremendously over the last few months as relentless cold has gripped the Eastern half to two thirds of the nation. This weather pattern has absolutely been freakish, frustrating, and at times absurd. So what in the heck is going on? Earlier in the year the Climate Prediction Center was forecasting above average winter temperatures for the Upper Midwest and Southern Canada. They were also suggesting it would be wetter and colder than normal on the East Coast and into Florida, with wetter than normal weather going from Texas into California. Although they missed the mark for our area, I’d say the forecast was dead on in some aspects. After see a several year long drought, California has erased the drought in much of the state in just a matter of months, Florida has been ridiculously cold, and the East Coast has seen record breaking snowfall. Most of Canada (especially Vancouver) has seen milder than average temperatures (January especially). On a global scale (including land and ocean temps), December was the 10th warmest on record (records date back to the 1950’s and 1960’s), so that’s nothing super special, but important.

January

Here’s a map of several locations around the globe where red means above average and blue means colder than average:

You will find that the majority of the globe was warmer than climatology (average) , and some areas that have been colder than average too. January around the glove was the 4th warmest on record, which is telling and I think significant, though only one month. This is weather we are talking about, it is not always predictable and the interaction of El Nino and other patterns are not always the same year to year. But my point here is that our cold has been the result of a record breaking amount of snow in December, and a blocking pattern. We have not seen progressive changes like we normally do. Back in January was the one exception when for two weeks we had above average to above freezing temperatures, but outside of the snowpack in Central Nebraska it was in the 40’s, 50’s, and 60’s far enough west into the Cornhusker state. Had we not seen the 28″ of snow cover, we too would have seen some extremely warm weather. Beyond that period of warmth, we’ve seen a jammed pattern in February with a ridge on the west coast, and trough east of the Rockies. This is a blocking pattern that keeps warmer air from ever reaching the Midwest as it normally would occasionally in the winter.

Here’s the blocking pattern, with the ridge smaller than it has been in Western Canada:

 Instead, we get a north wind and nothing but non-stop cold coming down from Canada. That is why we have not even hit 40° in Sioux City since early December (Norfolk, O’Neill, Neligh did that in January many times). In Sioux City and NW Iowa we have been stuck in some of the coldest air that the country has been experiencing, and we have really felt it and will never forget it. That’s my take on this winter from the research I’ve done. The legacy of our deep snow cover will continue to haunt us I think through March and April unless the blocking pattern can completely disappear, which will take time. Next week it might take a small break and hopefully we can go above freezing! Here’s to hoping anyway.

Dave Winslow

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