We didn’t really do a lot of forecasting this month, as most of our attention was tied to the dangerous and persistent tropical season. Dorian and Imelda took a lot of our attention, but when we were, albeit briefly, focused on the Mainland, it was WeatherNation who snuck in for a victory.
There is an enhanced risk for severe weather today in Minnesota, though at present, the radar is pretty sparse, save for a few showers in northern Minnesota and the first severe storm in northwest Iowa.
This radar imagery is from about 4:15. Here is a look at the HRRR forecast radar for about 630 this evening.
It looks as though the guidance is a little behind schedule, but the most important thing to note, will be how fast this line develops. This is the forecast radar 45 minutes later, or 715.
This looks like a strong line from Mankato to Storm Lake. Note the distinct blobs within the line. The threat for tornadoes and large hail is real tonight, and it is evidenced by the depiction of discrete cells within this line.
Eventually, and only within another 45 minutes, the storm will metastasize into a line. It will still be strong, and straight line winds will be added to the mix of threats.
This is the epitome of the “pay attention to the skies” days in southeast Minnesota and northern Iowa. Strong, dangerous storms are likely tonight, and they are likely to develop rapidly. It is possible that strong storms can develop and produce tornadoes even between radar scans with rapid development such as this.
Stay alert, heed local warnings, and listen to your gut. If it seems dangerous, take shelter, even if a warning has not yet been issued.
*Even as I was writing this, a tornado watch was issued for the region*
Meteorologists everywhere feel a twinge of guilt and pain every time severe weather targets life and property. We all love the weather, but when it turns ugly, it hurts a little differently, like we have somehow been betrayed. It’s worse when the bad weather is somewhat unanticipated.
Imelda was never anticipated to be a strong storm, in terms of central pressure, or wind speed, and it wasn’t anticipated, originally, to linger very long. Eventually, the storm did slow down and tracked over the same tract of land for about 48 hours. The result is images that resemble those from Hurricane Harvey, particularly between Houston and Beaumont.
Here is a look at the heaviest rain of the past 24 hours. There is a swath from the Woodlands in the east Houston metro to Beaumont that saw 10+ inches of rain today. Over the course of the storm, that same area saw close to 2 feet.
I’ve underlined Houston and Beaumont on the map which should show you something else from a couple of different perspectives. Either you will see this map, depending on your perspective. Either you will note that the is a lot of rain for a very large area, or you will note that this is actually a lot less rain than the area saw with Harvey. Both conclusions are true, and should be telling.
Even though there is quantitatively less rain from Imelda, there was a lot of rain for a very large area IT was disruptive, deadly, destructive and evocative of the all time crisis that Harvey brought. This should underscore just what a nightmare Harvey was, but also sound an alarm about the eminent threat of any tropical feature. Just because Imelda’s torrential rain affected a smaller footprint doesn’t mean it wasn’t a major catastrophe. Imelda didn’t bring 5 feet o rain, but 2 is still pretty overwhelming.
Before we begin, I want to highlight just what a miserable several days it’s been in southeastern South Dakota. Three EF-2 tornadoes embedded in a strong squall line tore through the south side of Sioux Falls, the state’s largest city Tuesday night. The massive devastation goes to prove, once again, that these strong squall events should be taken very seriously, because these tornadoes were so quick and briefly on the ground, they were over almost as soon as they were detected on radar.
The heaviest damage seemed to occur in one of the main commercial areas of the city, passing through a shopping center and a mall parking lot, and most noticeably tearing to shreds an Advanced Auto Parts. The City of Sioux Falls added this drone footage to their Twitter feed.
Here's a first look at the severe storm damage that occurred last night in Sioux Falls. pic.twitter.com/WyozEC0b8Q
While the tornadoes were embedded in a squall line, the squall line was a part of a persistent pattern of wet weather, that brought massive flooding to southeastern South Dakota and southwest Minnesota. Large tracts of I-90 were closed west of Sioux Falls to Mitchell, and many towns, including Madison, were cut off from the outside world by the rising rivers and creeks in the area. Many places received a foot of rain in a 72 hour period, and the region will remain wet this week. Let’s hope for better days soon.
As for the forecasting in the month of October, WeatherNation’s strategy of associating closely with the Weather Service and changing course only when necessary really only works if you find those situations where you can add value on your own. Well, in August, they did. Not only did WeatherNation win the forecasting title, the NWS dropped all the way to third. Congrats to WeatherNation. (Charts below are for daily forecasts)
By now, we’ve all heard the stories of utter devastation for the northern Bahamian islands of Great Abaco and Grand Bahama. The initial storm surge put a lot of Abaco underwater at the initial landfall, and many deaths on the island were the result of drowning during the storm surge, while in this case, the eye’s passage overhead provided a chance for many to get to higher, safer ground.
The storm then sat and spun over the eastern side of Grand Bahama, cutting the largest city, Freeport, off from the rest of the island. The destruction there, thanks to persistent triple digit wind speeds and a very high storm surge, is comprehensive.
This is the Grand Bahama International Airport. Planes were blown off the tarmac, and buildings were destroyed. These are some of the first planes able to land since Dorian bringing doctors and nurses and medical supplies. @WPTVpic.twitter.com/VEDdwoPydg
Dorian’s slow down fortunately spared the Floridian coast from the worst damage, but the storm spiraled northwards and pummeled Georgia and the Carolinas with rain, storm surge, tornadoes and category 2-3 winds, before it made a brief trek over the Outer Banks, with a landfall at Cape Hatteras. Take a look at the radar imagery to see how close the eye was to Charleston and Wilmington at various points.
Dorian moved away from the Carolina coast and as he weakened, broadened his footprint, meaning more rain and cloud cover further from the center of the storm. A course directly up the Gulf Stream and away from land will allow for maintained intensity until he made another landfall, this time over the weekend in the Canadian Maritimes.
Dorian tracked directly over Halifax, Nova Scotia with hurricane strength winds, and thought it didn’t approach the intensity it had when the storm swept through the Bahamas, he did considerable damage there as well.
The above video provides a good recap of the storms entire course. At least 45 people are confirmed to have died in Dorian’s path, with the majority of the fatalities in the Bahamas, though many more are possible when the affected islands are accessible.
If you can help out and choose to do so, the Red Cross is always accepting donations.
Because of the slowed down pace, Dorian was able to deepen further than forecasts originally expected, and has become a Category 5 storm as it bears down on the northern Bahamas. It has developed a well defined eye, as a symbol of it’s strength.
That’s a remarkable satellite image, in all of the worst ways. Dorian is going to prove very dangerous to the northernmost islands of the Bahamas, and it appeared he was on his way to becoming the strongest storm to hit the east coast of Florida since Andrew, but alas, that slow pace may have spared Florida the worst.
The slow pace has allowed Dorian to reach the Gulf Stream as what had been a stout Bermuda high breaks down. Instead of intercepting Florida, Dorian is expected to veer poleward to such a degree that he may not make a continental landfall until Nova Scotia.
The NHC maintains warnings for the northern Bahamas, particularly Great Abaco and Grand Bahama, which look to bear Dorian’s full brunt over the weekend, but at this time, only a tropical storm warning has been issued for a small stretch of Floridian coastline.
Dorian remains a danger, of course. The Bahamas in particular are in imminent danger, and even if the storm stays off shore as is now anticipated, waves of thunderstorms will still sweep from Florida to the Carolinas, with flooding a distinct possibility. There may be some lower end hurricane winds as well, particularly north of Miami, and in the Outer Banks of North Carolina. Even with these threats, though, it’s hard not to view the latest forecasts as anything but good news.
Dorian has just now been upgraded to hurricane status. He presently sits to the east of Puerto Rico, and will move across the virginiaIslands. Forecast trends have been for a slower progression, a bit removed from the Bahamas, both of which are trends that indicate a stronger storm than had been originally forecast.
Not last week, we were discussing the timid nature of Chantal, as she spun into the north Atlantic. Dorian was initially thought to be another fish storm (after he encountered the Lesser Antillies, of course) but now, the storm is getting slower, and is missing out on the steering flow that instead grabbed the short lived Erin, who is now spiraling off after Chantal.
Dorian is now expected to swing north of the Bahamas before curling back to the west towards Cape Canaveral in about 5 days time, with a landfall sometime this weekend. This is still quite a ways out, and there is certainly plenty of time for things to change, a caveat that is always in place for tropical features, but things aren’t breaking well in the last 48 hours.
A slower course will allow it more time to ingest warm, energizing ocean water, which would have been ok, if it had continued on it’s original course over Puerto Rico and Hispaniola, and through the Bahamas. Instead, it’s jogged east and north, avoiding most of the major landmasses in his way. Now, Dorian, which looks to take an unimpeded run at the Florida coast, may arrive as a major hurricane over Labor Day weekend.
If high pressure doesn’t develop with the strength expected over Bermuda, the storm may shift north, but if it does, it will press south. If the storm tracks directly over some islands, or shear is greater than expected, then Dorian will end up weaker as he landfalls on the Florida Coast. Unfortunately, none of those things seem as though they are expected to come to fruition.
The below track and intensity projections don’t ingest the European model. If they did, they would likely be more aggressive on a land fall closer to Vero Beach and Fort Pierce, with a bit more of an intensity peak at landfall. We’ll try to keep you updated here and on Twitter.
Tropical Storm names recycle every 6 years, unless they are retired. The powers that be update their lists every once in a great while, but Chantal has been a part of the lists since 1983, a solid 36 years, and six total cycles. Once, in 1989, a Chantal emerged in the Gulf and began dissipating as she hit the Texas Coast. That was the last time we have seen a Chantal of any significance.
2003’s Chantal was as close as we’ve come to remembering any Chantals, with $5mm of damage to the coastline of Belize. All told, given the scope of damage a hurricane can introduce, that’s pretty much coming away Scot free.
But it’s still more than most Chantals can say, including the one that just formed in the way north Atlantic over the last 48 hours. Check out the current satellite imagery of the storm.
Not only is Chantal disorganized, but the closest island is Newfoundland. This Chantal is going to be just as uneventful as previous iterations.
After a busy couple of years, not only is Chantal harmlessly out to sea, she is also the first storm in months. Granted, we are approaching the peak of the season, but there isn’t any development looming quite yet. With any luck, this entire hurricane season is one big Chantal.
Last night, massive supercells cropped up in the eastern plains of Colorado. A few tornadoes were reported, though there isn’t much population to really see much of a threat. The hail was more widespread, however, and it was gigantic.
Take a look at the tweeted imge of Colorado’s new largest recorded ahi slone.
Here is the record setting hailstone, shortly after it fell near Bethune, CO yesterday. Today, @NWSGoodland measured the stone at 4.83" in diameter and it weighed 8.5 ounces. Obviously, a little melting from its original size, but still beats the old state record of 4.5" #cowxpic.twitter.com/wjHCweQ1oq
The crazy part is that pattern didn’t change much, if at all. Tennis balls fell on the same location the very next night!
Not record setting tonight, but the same family that endured the record setting hail last night had another round of hail tonight. This time, about tennis ball size…and unfortunately window damage. @NWSGoodland@ColoradoClimate#cowxpic.twitter.com/yNlLZqDvFi
Hail stones are caused by strong updrafts, which cause droplets to accrete more and more ice and causes it to become heavier and heavier. The hail stone falls to earth when its weight causes the downward gravitational force to exceed the updraft force. Storms in eastern Colorado have had such intense updrafts so as a half a pound of ice could be suspended. These storms were fueled by the clash of dry air from the west intersecting the heat and humidity in the High Plains.
You can read more about the hail at the Denver Post.
After several consecutive years of drier than normal conditions, and severe drought and water shortages across California, a robust winter and a long spring have nearly reversed the trend, save for a slightly dry patch over the San Diego area.
Additionally, it doesn’t appear as though the drought will return even late this summer. A break is just what all concerned parties need this summer. Hopefully, it will persist next year as well.
