GRAND FORKS, ND (trfnews.i234.me) Watch the entire Spring Flood Outlook 2020 briefing.
all right good morning everybody this is Amanda leave the service a geologist with the National Weather Service in Grand Forks and I’ve got one of our lead forecasters here Jim Keyser part of our hydro hydro team here at the office who will also be helping out with the webinar today so we’re gonna dive right in try not to make this too long take up too much of your guys’s time so so as bottom line up front we got good news and bad news now the good news is there really hasn’t been any kind of change since our last outlook back on January 23rd that’s regarding weather conditions snowpack conditions or River outlook information since we really haven’t had a whole lot of precipitation since that outlook Jen era snowfall since January 18th which was our our last big storm before yesterday technically I was actually running kind of below normal to maybe he’s near normal in some spots and we’ve continued to be somewhat mild other than a few chilly days like we’ve got now throughout the winter so our frost step continues to be shallower than normal so on the other hand the bad news is we also have little change since the January 23rd outlook what I mean by that is the fall was still wet the early winter was still wet we still had record precipitation for then for them and the soil moisture is still high due to that and we are kind of looking at the February March April timeframe precipitation may be to track a little higher be a little wetter as we head into spring along with a little cooler but I want to see if that pans out so last outlook we were kind of touting the possibility of a top 5 flood and that was due to the precip conditions we had leading up until that point but we are starting to run out of winter thankfully we still don’t have to worry about spring so not completely off the off the table yet at this top 5 flood could still happen so here is the new outlook categories and colors you can see the major moderate and minor and the different colors for all of our River forecast points and I think there was only one single point on this whole graphic that changed for this look and that was for out in the twin Valley area so on I think it went from major down to moderate 50% chance other than that the 50-50 chance of reaching major moderate or minor has stayed the same with us outlook issuance that all the rest of those forecast points we’ve already seen a lot of this information so I’m gonna try to go through it kind of quickly but just as a reminder last fall and into November was a record wettest period for the state of North Dakota and then that leads into the entire year of 2019 was a record wet year for a calendar year of 2019 for the entire state soil moisture obviously hasn’t really changed much with our snowpack on the ground so we’re still up in that 99 plus percent aisle across the entire Northern Plains and Upper Midwest precipitation up through the 11th so this is skipping over that blizzard yesterday which really wasn’t much of a precipitation maker as it was wind and blizzard there was a little bit of precipitation accumulated but not a whole lot but focusing on the period from September 1st until Tuesday through February 11th the entire basin was running 4 to 8 maybe even a little higher than 8 inches above normal for that entire period so that’s nothing new everybody knew that but the good news is is that most of that fell before that January 23rd outlook so since then has been fairly quiet looking at numbers specifically for Fargo and Grand Forks you can see in the top top table there from September 1st through February 11th Fargo’s had eleven point six two inches of liquid precipitation and that brings them in at the third wettest on record for that time period which actually dropped them down to third from second so we were ranking a little higher but with our quiet conditions the last few weeks with Fargo area did drop down to third place at a second and you can see here since our last outlook they haven’t even had a tenth of an inch of precipitation since then that’s not including yesterday’s but that was pretty minimal too as for grand forks on the bottom table you can see we’re still well above and soundly in first place there and that was mainly due back to that September flash flood heavy rain event still and since the January 23rd outlook we’ve only had six hundredths of precipitation not including a little bit more yesterday so really very fortunate that’s been pretty quiet we’ve shown this graphic before but it’s a nice reminder to look at I’ll show you the black bold line is showing you the the streamflow for the Red River at Grand Forks throughout the years 2018 and 2019 from left to right on the graphic and as it gets higher and higher and more into those those blue shaded regions you’re getting more into that above normal so you can see that September October November period last fall that black balled line did peak above that blue part showing that we were at record record levels for that time of year at the Grand Forks gauge location moving forward for same for at Fargo looking at the black bold line for last fall you can see we weren’t quite record we weren’t quite above those blue peaks but pretty darn close so we still were at the very very high end of River levels ever seen for that time of year and then we went into the freeze up at these levels so like I mentioned at freeze up you could look at the black shaded area the few streamflow observations we had back in December when we froze up showing that we were much above normal or high or probably even record for a lot of the locations in the southern Valley so Wilke real quick everybody’s seen these spring flood ingredients before so first to fall moisture based streamflow we already covered those we had plenty of fall moisture record levels based streamflow plenty of flow record levels of that also so then we head into the next three factors for the winter like I mentioned earlier frost steps are still running below normal only in eight to thirty inches which is lower than we were last year on that that’s thanks to the early snow pack cover that we did get earlier this winter winter snow pack we can still consider above normal for this time of year thanks to the early activity we had I mean but thankfully the last three weeks we haven’t really added to it so that’s that’s good news the far northern Basin remains the driest porche portion of the basin with the least snowpack snow water equivalent or the amount of water that’s sitting in the snow that’s out there right now is high we’re still sitting around those values that we normally would see at the end of the winter season as we head into spring but we haven’t really added to them the last few weeks so so that’s the good news it’s a real quick going through frost depth generally 10 to 30 inches across the northern two-thirds of the basin in the south a little less but still still kind of around normal even lower than normal so we are a little shallower not frozen as deep as we were especially last spring snow depth this is as of yesterday kind of a general range of 10 to 20 inches across the heart of the basin and then the far southern basin and over into the Devils Lake Basin has has less maybe 6 to 12 6 to 15 6 to 16 kind of kind of in those ranges so it is a little high for this time of year since we still do have some winter to go but we haven’t been adding to it same thing with the snow water equivalent in that snowpack kind of 3 to 5 inches up and down the valley lesser in the south and the north and then over towards the Devil’s Lake Basin so kind of that Oslo to Grand Forks down through Fargo and then either side of the red are definitely the hardest areas where they have more water content in their snow a quick comparison a graphic there’s kind of a lot of words on here February 2011 so at this time back in 2011 we did have one to three more inches of water in the current snowpack and the southern and Central Valley so that’s good news that 2011 it was still a bit higher than we’re sitting right now and as a side down at the bottom February 97 also had higher snow water content well February 2009 actually had less so it kind of kind of depends also as everybody knows how the spring is gonna play out so the amount of liquid water in the snow isn’t the end-all be-all for what kind of flood we’re going to see it’s just one of the indicators so what’s next the last two ingredients how was the spring thaw cycle gonna go and are we gonna see any spring rains so obviously that’s yet to be determined but they’re gonna end up being pretty big factors as we head down the stretch here so what’s upcoming weather wise here’s for the next week precipitation so through next Wednesday pretty much not a whole lot expected a few weak minor systems quickly passing through might bring a little bit of some light snowfall but generally less than a tenth of a liquid precip expected moving into the week after that so we’re kind of looking at that February 20th to 26th timeframe maybe we’ll move into some above normal temperatures get out of this freezing cold that we’re in right now and be a little quieter precipitation rise and then after that for the rest of the end of February maybe a little active more active at the end of the period kind of hard to tell at this point this outlook was issued a few weeks ago already so what remained remains to be seen what will happen through towards the end of February and lastly the February March in April looks so getting us through the bulk of our melt the same outlook that was issued on January 16th hasn’t been updated quite yet continues to show below normal temperatures and above normal precipitation so if that were to come true that would lead us to you know our delayed melt with the potential for quicker runoff a faster melt with maybe some rain on top of it but this should be updated here in the next few days so we’ll see how that how that changes so real quick here’s our graphic again showing moderate to major flooding pretty much across a good extent of the valley but not a not a whole lot different from what we put out with our look I’m just gonna run through a few quick hits of the highest forecast locations at this point so the wild rice river area we are expecting to see quite a bit of runoff down there pretty good chances for being above major no matter what happens from here on out maybe even towards that high end so and here’s our additional pea foster probabilistic flood outlook summary graphic kind of showing that same data just in a more easily digestible format so you can see then the 95th percentile and all the way up to the 5th percentile or well above the major flood line so pretty much pretty much a guarantee down at Abercrombie for Fargo the same thing these numbers actually changed pretty very little the biggest difference at Fargo was kind of that 95 to 98 99 percentile did bump up a little bit while the higher end up here at your 1/2 percent did go down a little bit so they did start to narrow that range a little bit for the Fargo area which will see more and more as we get closer to the spring but it’s still gonna depend on on how the rest of the spring plays out but pretty solidly into major flood category with the current conditions that we have out there right now for Fargo same things shown here 95 percent and downward is all above major flood category Cheyenne might be one of the more active regions to pay attention to as we head into the spring here which would be kind of a change from what they saw last spring although in the fall they were pretty active too so this is an area to keep an eye on pretty good chances of exceeding major flood category there as we stand right now so that’ll be an area to watch however you could tell easy more easily on this graphic how large their spread is so you know 90 percent chance of getting pretty close to a minor flood stage and then and then things ramp up a little bit from there but still a lot of spread a lot is going to depend on what happens as we head through the rest of the winter and into the spring here for up and down the Cheyenne for Grand Forks kind of the same thing as Fargo that upper end went up a little bit or the lower end went up a little bit while the upper end went down a little bit kind of closing that gap but still pretty good chances of a major flood stage there if we get lucky maybe we’ll stay a little lower down and moderate but we’ll see same story here a lot of a lot of numbers clumped together there above a major flood category but pretty much sure bet they’ll at least get in the moderate Oslo nothing new there plenty of breakouts pretty much guaranteed no matter what happens with the weather conditions from here on out above major flood category likely access to town will be shut off the same old story there you can see here couldn’t even fit a lot of numbers on here because they were so close together pretty much a guarantee above major flood stage Grafton little once we get further north into the valley a kind of above the that graft in Oslo and the rest of the valley up to the north a lot drier up there with chances not not nearly as bad as down south for for decent flooding do note that these numbers for Grafton do not take into account the bypass that has been built so the river gauge will not actually display what kind of values we’re gonna see here but for areas outside of the diversion or outside of the city that aren’t protected can still use these for planning purposes and compared to past years on how they could prepare for these kinds of levels so like I said pretty low chances here maybe action maybe in the minor flood stage and if things really get get crazy through the end of the winter and into the spring we could maybe we should reach up into the moderate and major levels I think the last one I picked out here to show was for Pomona so same thing at Oslo here all up and down the red will be pretty pretty high river levels pretty good chance as a major flood stage so pretty much a guarantee to get into that major category up at Pembina and that’s also shown here last but not least here’s the latest for over in the Devils Lake Basin so so currently they’re sitting at about 14 49 feet which is about a foot higher than they were at last year at this time thanks to the the wet spring or wet fall excuse me they are looking at good chances in that 25 to 75 percent range of a 2 to 3 foot rise so they haven’t seen these levels for several several years so that wet fall really pushed them up into a higher category than they they normally could have been so lastly the same thing the good news is that we haven’t had a whole lot of change in the last few weeks so most numbers from the January 23rd outlook remain pretty close to the remaining valid I haven’t had a whole lot of precipitation or snowfall pretty mild for the most part so our frost step continues to be pretty shallow especially compared to last spring but the bad news is that the stuff that already happened and fell precipitation that fell earlier in the winter and fall is still there so we’re still tracking that snowfall that’s already on the ground and the wet soils that we had from last spring so climate outlooks continued a favored cooler and wetter this spring we’ll see how that pans out and if any updates kind of start changing that around still looking at the potential for a top 5 flood but it’ll still depend on what happens the rest of the winter in the spring so we continue this quiet period that would be great we’ll have to see what happens as we continue on here so here we are in closing moderate to major up and down the valley on the tributaries for the most part – lesser chances on the tributaries in the far northern Valley for any kind of moderate to major flooding a little drier up there so will we still be higher than spring 2019 we’ll see how the winter and spring play out and see how that works out
SPRING FLOOD OUTLOOK: Full Briefing by Grand Forks National Weather Service (Video)
