The Longest March
"It'll melt" my wife muttered yesterday, sick of me whining about the prospect of a towering pile of slush - 10 weeks away from the Summer Solstice.
Just when you thought things couldn't get any stranger. Here comes another baffling "Black Swan" weather extreme: ice, sleet and snow today, then heavy snow tonight into Thursday. Our in-house weather models hint at near-blizzard conditions here Thursday morning. Models print out over 2" liquid; at least half that amount falling as heavy, wet, gloppy snow.
Ice, coupled with high water content in the snow, may bring down tree limbs. I wouldn't be surprised to see some power outages. Yes, one of the biggest snowfalls of winter will come during the second week of April.
Even with a snow ratio of 8:1 (8" snow for every inch of liquid precipitation) the metro may wind up with 6-12" amounts by Friday - southwest MN could pick up 20-24". This factors in relatively warm ground temperatures and some melting of snow on contact (mainly today). Right now Thursday appears to be the worst travel day, statewide.
Flurries taper Friday morning, peeks of sun Saturday - the atmosphere warm enough for rain on Sunday. Whew. The ECMWF shows more light rain/snow by next Wednesday, but nothing like the next 48 hours.
This may wind up as the biggest April snowfall since 1983. Before you consider hijacking a southbound barge on the Mississippi: long-range models show 50s the last week of April.
Light a candle.
A POWERFUL STORM SYSTEM WILL PRODUCE A COUPLE ROUNDS OF WINTRY PRECIPITATION OVER THE NEXT COUPLE OF DAYS. THE FIRST ROUND OF PRECIPITATION WILL ARRIVE LATE TONIGHT IN THE FORM OF A WINTRY MIX OF RAIN...FREEZING RAIN AND SLEET ACROSS MOST OF SOUTHERN MINNESOTA AND WESTERN WISCONSIN. MORE SNOW IS POSSIBLE ACROSS CENTRAL MINNESOTA. HOWEVER...SNOW TOTALS WILL BE LIGHT TONIGHT AND THROUGH THE FIRST HALF OF WEDNESDAY. THE WINTRY MIX COULD CREATE SOME SLICK SPOTS FOR THE WEDNESDAY MORNING COMMUTE. A SECOND MUCH MORE SIGNIFICANT ROUND OF WINTER WEATHER IS EXPECTED LATE WEDNESDAY AFTERNOON INTO THURSDAY AFTERNOON. ALTHOUGH THERE STILL COULD BE A MIX OF SLEET...RAIN AND SNOW IN SOUTHERN MINNESOTA AT TIMES LATE WEDNESDAY...MANY LOCATIONS WILL MAKE THE CHANGE OVER TO MODERATE OR HEAVY SNOW WEDNESDAY NIGHT. SNOWFALL ACCUMULATIONS OF 10 TO 12 INCHES WITH LOCALLY HIGHER AMOUNTS APPROACHING 14 OR 15 INCHES ARE EXPECTED IN A BAND CENTERED ALONG A LINE FROM REDWOOD FALLS...TO THE TWIN CITIES METRO...TO LADYSMITH IN WISCONSIN. SNOW TOTALS WILL DROP OFF TO THE NORTH AND SOUTH OF THIS HEAVY BAND TO JUST 4 TO 6 INCHES NEAR ALEXANDRIA AND LITTLE FALLS AND PERHAPS AS LITTLE AS 3 TO 5 INCHES NEAR THE IOWA AND MINNESOTA BORDER. LOCATIONS IN SOUTH CENTRAL MINNESOTA SHOULD END UP WITH MORE SLEET AND FREEZING RAIN.
* 1 to 2 foot snows are imminent from northern Nebraska to Pierre, Sioux Falls and southwestern and west central Minnesota. On our nuisance-plowable-crippling snowfall rating scale, this will be crippling for South Dakota and portions of Minnesota, with as much as 6-12" in the Twin Cities by Friday morning, like something out of mid-February.
* High water content (1-2+" liquid) will mean a very heavy, wet, sloppy snowfall capable of bringing down tree limbs and power lines. I expect sporadic power outages at the height of this slop-storm Wednesday & Thursday.
* River, stream and urban flooding will accelerate from Wisconsin into the Chicago area over the next 48 hours, as 2-3" rains fall on partially frozen ground.
* Moderate threat of severe storms over central Oklahoma. I expect a few large, violent, long-track tornadoes from near Oklahoma City to Tulsa this afternoon.
Summary: Much of the central USA will earn it's spring this year. What will probably be one of the Top 10 April snowfalls on record will impact a wide swath of the Plains and Upper Mississippi Valley from today into Friday. River flooding will accelerate, with the greatest concerns from Wisconsin into Chicago, Indianapolis and Detroit. The cold, snowy weather has delayed peak crest for the Red River in Fargo, but added moisture in the snowpack will probably make a bad situation worse, with an eventual crest still 1-2 weeks away. Deep into the warm, humid air tornadoes are likely between 2pm and 9 pm today, with the greatest potential for destructive tornadoes from north Texas into Oklahoma.
This is a volatile, high-impact pattern, affecting 20-25 million Americans over the next 72 hours. We'll keep you posted.
Graphic credit above: "Climatology, the scientific study of climate. can help predict who typically sees the most active severe weather, but it can’t yet create a seasonal forecast." Image via NOAA/SPC.
While viewed largely as saber-rattling, the idea that the networks could be converted into cable channels gained attention in the television world because such a move would have wide-reaching implications for viewers and station owners.* more details from Brian Stelter at The New York Times.
The possibility had not been publicly broached by a major broadcaster until Chase Carey, the chief operating officer of Fox’s parent, News Corporation, spoke at a conference of broadcasters on Monday morning..."
Severe thunderstorms require two primary ingredients:
1) Energy or fuel supplied from hot, humid air to feed violent vertical storm motions (updrafts and downdrafts). A common metric for this is a quantity called CAPE, convective available potential energy.
2) Turning winds with altitude, or wind shear to help storms spin. Wind shear is driven by temperature contrasts and is a necessary ingredient for tornadoes..."
Image credit above: NOAA.
Photo credit above: John Kerstholt - Wikipedia.