We’ve all been captivated by the scenes from Kilauea and the communities of Leilani Estates and Pahoa, where fissures from the erupting volcano have emerged in the middle of neighborhoods, forcing evacuations and causing fires as the slow moving lava has no shortage of fuel.
One thing that separates Kilauea from other volcanoes is the slow creep of lava, coupled with a tropical location. Instead of the various gasses settling out with the dust and ash cloud, emitted in an explosive eruption, it’s seeping out slowly and hanging, alone in the skies above Hawai’i.
Hawai’I is well known for its countryside, which is only possible because of all the available moisture in the area. Inevitably, a tropical wave will move into the area, and the winds driving into the high peaks of the Big Island will form rain showers. Now, however, the uninvited guest of sulfur dioxide will mix with the water vapor forming clouds.
As a result, acid rain is a real possibility for part of The Big Island around Kilauea. Fortunately, sulfur dioxide is a fairly heavy compound, and the threat for such an event covers a small area geographically. Still, Hawai’i is known for plant life, which will be effected by the potentially dangerous rain, and one of Hawai’I’s largest cities, Hilo, is downhill from Pahoa and Leilani Estates.
When Kilauea finally stops erupting, the first heavy rainfall around the volcano should effectively eliminate the threat of continued acid rain. Unfortunately, the geology is tougher to forecast than the meteorology in this instance, and nobody quite knows when that will be.
There was one steady forecaster throughout the month, and I could still rarely believe who it was every time I performed a verification. There were machinations, and a very tight race from 2-7, (I’m happy to say Victoria-Weather came on strong for 2nd at the end) but the title holder led for most of the month. All hail our robot overlords: Forecast.io was the forecaster of the month of April.
Tuesday was the first rough weather day, in terms of widespread severe weather, in the Plains for 2018. There was a streak of severe reports through central Kansas, as well as four different super cells that appear to have produced tornadoes, two northwest of Salina in Kansas, another along the Nebraska border and a fourth south of Kearney, Nebraska. To this point, it doesn’t sound like there was much structural damage, nor any injuries or fatalities, which is obviously excellent news.
Within these storms, however, there were reports of hail reaching up to 4 inches in diameter and damaging straight line winds, suggesting the intensity and organization of this feature. Unfortunately, the set up isn’t really changing, aside from a slight shift to the southeast, bringing with it the same threat for long track, if isolated tornadoes, large hail and strong winds. The greatest threat is highlighted by the SPC in red.
The red, moderate risk contains towns like St. Joseph, Missouri, and the northern metro of Kansas City, and closely correlates to the center of low pressure for this system. Expect more general thunderstorms in the arm extended towards Michigan, but the cold front southwest through the Big Bend is more likely to produce widespread severe weather, by my estimation.
Unfortunately, the conditions that occurred on Tuesday in Kansas and Nebraska are very dangerous, and are likely to be repeated on Wednesday. On Tuesday, they occurred in sparsely populated locations, but it seems less likely that we will be so lucky on Wednesday.
Back on April 14th, a steady stream of heavy rain pummeled the northern part of the island of Kauai, the westernmost major island in Hawai’i. The northern end of the islands are exposed to the trades and most of the features that drift across the Pacific, so northern Kauai isn’t unfamiliar with heavy rain from time to time. This was something else though.
A sensor in northern Kauai reported a 24 hour rainfall of nearly 50″ which topples the American record which has stood for about 40 years, dating back to Tropical Storm Claudette in 1979 in coastal Texas. For comparison, the maximum total from the devastating Hurricane Harvey was about 60 inches, over the course of several days. This was nearly as much in a quarter of the time. The annual rainfall at Victoria-Weather HQ is about 30 inches!
For more on the devastation and the recovery efforts in this remote part of Hawai’i, read Brittany Lyte’s article on the event, or check out KHON‘s video story of the event.
Finally, at long last all the snow that has fallen across the country has mostly melted as 60s extend all the way to the Canadian border. There isn’t much kinetic weather to talk about tonight, aside from a few thunderstorm in the Abilene area, so instead, I will pass along this map of the current watches and warnings for the country.
It’s a little difficult to make out, but the center of the country is littered with green dashes, representing river flood watches and warnings. Be careful around moving waterways like creeks and rivers, especially where snow is finally melting, from the North Rockies all the way through the Mississippi and Tennessee Valleys, as water will be a bit high.
For most of the spring, the country has been plagued by a broad, slow moving wave right across the center of the country. It’s been spectacularly unpleasant, with Arctic air lingering over the continent of North America for the last couple of weeks, introducing record lows and several late season snow storms.
Fortunately, the tide seems to be turning. The mean jet flow is finally forecast to shift north, indicating that the chilly air will finally be pent up where it belongs, at least for the long term. As you can see with the forecast jet stream analysis for Monday, the continuous stream lies just north of the Canadian border.
Thee will still be a threat for a cold air invasion late next week, but not nearly on the scale that we’ve seen for the beginning of the month, as the pattern has become much shorter in wavelength. Any period of cooler air will be briefer, and won’t be able to sneak as far south.
The jet is retreating, along with the cold air, but it isn’t switching pattern immediately. The northern part of the country is simply moving closer to normal, rather than suddenly moving above normal.
Yesterday, Anthony discussed a spring system that’s headed for the Plains, and he focused particularly on the threat for snow in the Upper Midwest. Run to run, it’s been pretty speculative as to where and how much snow would fall. I tend to hedge towards the lower end of the spectrum, of the opinion that more warm air will surge north because April Gosh Danged 12th. Some people are more pessimistic, and they have every right to be, given some of the model runs and how depressing this spring has been so far.
There is quite a bit of uncertainty over the amount of snow or where it will happen, but the storm is showing signs of looking extremely springlike in at least one manner. We are looking fairly locked in for a broad severe weather outbreak this weekend, as the cold front moves across the south central US. Already there is an enhanced risk of severe weather, and I would be surprised if there isn’t a moderate risk as we approach the valid period.
The outlook for moderate storms presently stretches from Kansas City to College Station for Friday. A sure sign of trouble ahead is the expectation of severe weather on the 3 day outlook, which has an outlook for a triangle from Clarksville, TN to Tallahassee and Lafayette Louisiana. The threat for severe weather is far more tangible than the snow expected.
There will be no primary threat out of this system – The trifecta is possible, from tornadoes to strong winds and large hail, thanks to the layout of the storm, with a tightly wound area of low pressure to the north to a strong, active cold front in the south.
Having a bunch of strong thunderstorms in the southern US, tied to an active snow storm is a very typically March pattern, and is a sure sign of the seasonal transition. The problem is that the season should have already transitioned at this point.
Last week I wrote a post about a strong spring system that simultaneously dropped several inches of snow across the Upper Midwest while further off to the south, a severe outbreak swung from the Mid-MS River Valley into the Ohio Valley. A similar setup is shaping up for this weekend, with the chance for even more prolific snowfall totals.
An strong cold front is set to push over the West Coast during the day Wednesday bringing plenty of rain to the Pacific northwest down to the Sierra’s as well as high elevation snow. As the system works into the Great Basin, a new area of low pressure looks to develop and push through the Central Rockies while it intensifies, which is also expected to bring high winds to the Intermountain West. As the low pressure pushes out over the Central Plains on Friday, it will tap into plenty of Gulf moisture for it to transport northwards. This looks like another heavy snow setup for the Dakotas into the Upper Midwest while the MS River Valley gets targeted for some severe weather. While the models are still a bit too far out to get an accurate idea of just how much snow the north will get, it looks like SOMEwhere is going to get hit with a bulls-eye of 12-18″. Where will it land? Stay tuned!
The story of the spring so far has been the relentless cold, marked at times by strong systems moving through the northern US, leaving unseasonably snowy tracks through the region. This story, however, was confined largely to the part of the country that lies east of the Rocky Mountains. Points to the west were actually in the throes of warm, even unseasonably hot weather.
A great example of that is Phoenix, where Tuesday’s high will be 100 degrees. That’s significantly warmer than normal. We’ve been stuck in a standing wave pattern, with a trough in the west and a high amplitude ridge in he west. Expect that to change by week’s end.
A trough waiting just off the coast will move inland around Thursday, bringing quite a bit of precipitation to the western US. That will certainly be a big part of the story as the weekend approaches, but don’t miss out on this other component: Most of the country will see temperatures that are below normal, at least for the weekend.
We’re a full fortnight into Spring now and people are itching to get outside and start doing fun outdoor things. Mother Nature, however, especially for us in the Upper Midwest, refuses to let us escape Winter’s frigid grip. A strong low-pressure system working through the Central US over the last 24 hours has brought a swath of snow from the Dakotas through MN into WI and continues eastward through the Great Lakes. Areas around the Twin Cities got 6-10″ today and continues to pile up in WI. Meanwhile, on the warm side of this system, strong to severe thunderstorms rumbled their way from Indiana/Ohio all the way down to coastal TX. Strong winds accompanied severe storms from Columbus, OH down to Eastern TX into MS, and while that was the most widespread severe effect from this sytem, over 110 reports of large hail were also reported.
Storms like this aren’t rare for early Spring however. On this date in 1974, a similar but stronger low pressure system was making its way through the Central US. Over the Upper Midwest, a swath of snow fell across MN and WI accumulating up to 6-12″ (7.3″ specifically in the Twin Cities). What this system is more well-known for, however, is the widespread tornado outbreak that hit the Midwest down to the Deep South. 148 tornadoes happened over a 24-hour span in what became known as the Super Outbreak, the largest tornado outbreak on record in the US. This would remain the US record until the 2011 Outbreak which more than doubled that number! Luckily, no historic tornado outbreak will develop from this system, but we do have to be wary of all kinds of inclement weather this time of year!