I am presently enjoying a vacation with my extended family in the Black Hills of western South Dakota, and we’ve had a bit of active weather in the last couple of nights. Tonight, we were in a severe thunderstorm watch, as a line of thunderstorms swept in from Wyoming and brought rain and marble sized hail to our cabin before getting a boost from the eastern slope of the Black Hills, and accelerated through Rapid City and is now preparing for a voyage through the Plains.

Last night, however, was different. An isolated thunderstorm, aided in part by the very mountain we are staying on, cropped up and stayed in the same spot for well over an hour. Here is the view from just to the north of the storm.

We were almost directly under this storm, and the radar confirmed our suspicions.

The storm did eventually expand and bring some drops of rain, but not as much as points on other faces of the mountain!

It was an interesting thing to see in action, the force of the terrain, and the structure of the storm that produced all of the wet weather to other parts of the mountain was pretty incredible.

It was 90 degrees in Minneapolis today, which is certainly a pretty warm start to June, and tomorrow and the weekend will only get hotter. Heat waves are certainly newsmakers, and in particular, they are big news when they arrive in the northern US. All this is true, and really, it’s not the most interesting part of this particular heat wave. Take a look at the forecast highs for Friday.

There is the typical hot spot in the Mojave, but otherwise, the warmest part of the country will be…. North Dakota? The interesting part of this heat wave, to me, is that it completely bypasses places to the south. The forecast high in Bismarck tomorrow is 101! Unintuitively, the forecast high in Austin tomorrow is 80, a full 20 degrees cooler. I don’t have to tell you this, but that’s not how it usually works!

Why is this going on? The answer is told in the upper air forecast. Take a look at the flow pattern forecast during the day tomorrow. I have added some arrows for your benefit.

The pattern over the US is tilted. The upper level trough over the eastern part of the US takes a westward turn and heads through the southern Plains. Forgive me, because the axis of the trough in the south is a little further north than I drew it, but the result is the same. Moisture is being drawn to the Red River Valley, and then it streams into the eastern Great Lakes, keeping the entire tract covered in clouds and rain.

Meanwhile, a ridge axis runs from the southwest towards the Upper Mississippi Valley. Remember how I noted how hot it was in the southwest? Well, that is where the air moving into the Dakotas is coming from. Combined with the scouring effect of the Rockies, the dry air can warm even more during full daylight.

When this pattern sorts itself out, the hot air won’t go anywhere, but instead of shipping off to the northeast, the moisture entering through Texas will find a route north. Until a cold front comes late next week, the heat of this weekend will become hot and humid.

It’s only June 3rd. and the summer is off to a hot, hot start in the Northern Plains.

We made it through what is historically the stormiest month of the year, and made it without many devastating headlines. Now we just need to tackle fire and hurricane season with so little bad news. This month, the best news for a forecaster belongs to The Weather Channel, who always seem to do well in the spring storm season. Kudos to them. Here is the look at the total wins for the year to date:

Outlet	Forecast Wins
Weatherbug	5.66
Victoria-Weather	5.5
The Weather Channel	4.5
Accuweather	4.33
Forecast.io	1.83
National Weather Service	1.83
WeatherNation	0.33

Large cone #tornado at 6:24 PM MDT southeast of #Kim, #Colorado yesterday. Difficult chase with terrain and road network but managed to find some high ground for this shot. Amazing chase day! #cowx #wxtwitter #StormHour @JimCantore @GarofaloWX @Wx_Max @USTornadoes @DopplerJess pic.twitter.com/l5gwoPMFX9

— Marcus Diaz (@TheTXWXchaser) May 30, 2021

There has bee quite a bit of severe weather in the last week, but it hasn’t really been a story in the news. Strong storms did a good job of avoiding large population centers, and never really threatened to move somewhere moer ominous. Any weather outbreak looks as though it will have to come at another time, as the severe weather in the Plains is going to wear itself out.

Tornadoes are common this time of year, and in the High Plains, thanks to the changing of the season, and the topographic advantages of the region. The flat, generally low density population of the region makes it popular with storm chasers, both of the academic, researching variety, and the thrill seeking tourist kind. The availability of weather data to the public has meant that May in the Plains can be thick with chasers, especially when the weather is busy. Such was the case over the last week, when tornadic activity was seen over many days from the Texas Panhandle to southwestern Nebraska.

Many videos were taken and twisters spotted, all without much harm to life or property. Call it a pretty successful chase season for all involved (except those who justifiably are a bit miffed by the idea of disaster tourism, especially in their home area).

The region, as I said, is a topographically perfect partner for storm chasing. The pattern this week set itself up nicely, and was long lived enough to encourage chasers to make the trek. There weren’t big areas of low pressure that dived into the region to make for dangerous outbreaks, like we see in the southeast or Ohio Valley when outbreaks occur there.

The Omega block over the eastern US allowed for warm, moist air to pump north on the western flank of the ridge, priming the pump for strong storms. In this environment, the tightly spinning lee troughs developing in the leeward side of the Rocky Mountains were able to trigger thunderstorms that were often well organized enough to drop tornadoes, often big, nasty photogenic ones that could be filmed from a distance.

In this case, they didn’t find any population centers, which is what everyone wants. With any luck, important information was collected. At the very least, cool images were taken.

In the past several years, some long standing meteorological terms have filtered out into the masses, and have exploded as buzz phrases, and often help to drive ratings and induce a mild hysteria. Think of how often you now hear the terms “polar vortex” or “bomb cyclone” for example. Right now, many meteorologists are talking about an “Omega block,” which is definitely much more innocuous than it sounds.

For those that are familiar with the Greek alphabet, you may know that the letter Omega is the last letter. This lends the Omega block terminology a bit of gravitas. Is it some sort of apocalyptical signal? Is it the end? No, assuredly not. The name is actually a reference to the shape of the Omega: Ω. The upper level jet features a ridge, bracketed by two sharp, potentially cut off areas of low pressure. This is the case today, and will be for a while.

Ridges in general are tough to dislodge, and having a immobile trough, as is the case off shore, in front of it, and even undercutting it, slows things down even more. This is why it is called a “block”. For a while, the upper level pattern is going to be unable to progress.

There isn’t a lot of danger in the pattern, especially at it’s current location. A little further east or west, the coasts could be in for a fairly rainy week, or the Plains could be in line for a major severe weather stretch, with low pressure unable to move our of the region. Instead, it will be dry from the Mississippi Valley to the East Coast, with just a few showers riding the western side of the ridge, a persistent but not terribly worrisome threat (despite a few tornadoes dipping down over southern Minnesota earlier in the week. )

This Omega will be in place through the weekend before it slowly starts to shuffle off to the Atlantic.

The beginning of May has certainly been warm here in Minneapolis! This comes after an April that was all over the map in so many ways. It took a great degree of forecasting skill to have the multifaceted forecasts that April required. Weatherbug won the month, and should fully embrace their victory.

Today is the 10th anniversary of a major tornado outbreak, which caused death and destruction across the southeast, most notably when a tornado hit Tuscaloosa, including the campus of the University of Alabama. This time of year has no shortage of such anniversaries.

This year, fortunately, there aren’t any major severe weather outbreaks on the immediate horizon. Model guidance is in lockstep over the next few days, so that can be taken with some degree of certainty that there isn’t a major event before the end of April.

That’s not to say it won’t be stormy. Every increment of the forecast features a little wave, producing showers and thunderstorms rolling through the country, particularly from the Central Plains to the Ohio Valley southward. It’s not always the same wave, and no area is going to be relentlessly active for the next several days, but there will certainly be many active radars in the south central and southeastern US through the end of the work week.

Beyond nationally calm Saturday, divergence begins to settle in. Timing and placement are askew for the various computer guidance that meteorologists have available. Going beyond 5 days for a forecast is never generally as accurate as one might hope, but for a lot of the country, Sunday and the early part of next week are all over the map.

One thing that is in concert, is that none of the model maps are quiet. There is always something going on. A broad trend like that can be relied upon, moreso than a forecast for a particular location. That means the country can expect to see a lot going on in early May, even if we can’t confidently say what we should expect quite yet. With the anniversaries of Tuscaloosa, Moore and so many other coming up this time of year, “action” is not something everyone should look forward to.

Every ten years, weather averages are reconsidered and updated. Daily high temperatures, low temperatures and precipitation are now based on the most recent 30 years, reflecting the most recent information in our ever changing climate. In addition to the daily changes, monthly and seasonal changes are also instituted.

Hurricane seasonal averages were updated, replacing the 80s with the extremely active 2010s. Now, an average season will see 14 named storms, with 7 hurricanes, up 2 and 1 from the previous averages, according to the National Oceanic and Atmospheric Administration. This is has a lot to do with the active years early in the past decade, and especially the last several years, which were busier than even the new normal years.

There is something to be said about the warming of the north Atlantic, but also, the El Nino pattern, which was more prevalent in recent years. Somewhat surprisingly, the eastern and central Pacific didn’t have any revision to their annual averages. The Atlantic also didn’t see an increase to the major hurricane forecast.

Satellite data and naming conventions really were revolutionized in the 90s. Improved satellite data will, as a result, not be a factor in future changes to averages, but they may have led to some change in this update. Hurricane season, officially, begins on June 1st, and we are coming off the busiest season of all time.

I’ve definitely said it before, and it was proven again this month. The Weather Channel comes through during months with terrible weather. They always seem to have their best forecasts when they are sought after the most, the sports equivalent of performing when the lights are brightest. Congrats to TWC for coming through when people counted on them most.

Outlet	Forecast Wins
Victoria-Weather	4.5
The Weather Channel	3
Accuweather	2.33
Weatherbug	1.33
Forecast.io	0.83
WeatherNation
National Weather Service

I posted last week about the high risk of severe weather that turned into a couple of long track supercells that fortunately avoided major population centers. Today, we weren’t as lucky.

There were a few tornadic storms, but one storm in particular will be remembered for a long time. Here are the storms that have been reported today, most notably a long track, large tornado that trekked from West Blocton, Alabama to Pelham, through the south side of Birmingham, and on to Ohatchee, where 5 people lost their lives, before the rotation fell apart just inside the Georgia state line.

This storm was strong enough that is showed up very evidently on radar. Note the red dot in the bottom left display, near Meadowbrook. The storm had crossed I-65 and was currently within a tornado emergency, suggesting a confirmed, large tornado in a populous area.

That pink triangle in the four displays reflects the rotation well. Remarkably, this tornado was on it’s way toward a subdivision where local meteorologist James Spann lives. He found out on air that his home suffered heavy damage as tornado passed nearby.

There were other tornadoes that cropped up throughout the afternoon in several states, including Mississippi, Tennessee, Alabama and Georgia. In fact, as this post was coming together, another tornado emergency was issued south of Atlanta, as a large tornado was moving through the town of Newman.

There are already reports of structural damage, and I suspect it will be much worse in the morning. The storm did dissipate before it reached Fayetteville, Georgia, but Tyrone and Peachtree City almost certainly received damage as well. The tornado moved through after midnight, local time, so many residents were probably caught unaware.

In comparing today’s storms to those of St. Patrick’s Day, the biggest change was the tornados’ ability to hit population centers. There were a couple of more individual storms, and the tornadoes will likely be measured as being stronger, but when it comes down to it, today, we were unlucky.