Monday, April 28, 2014

Debris Balls & PDS Tornado Watches - Another Major Tornado Outbreak Later Today Impacting Same Region


Positive Spin

I've taken all my meds and I'm determined to put a positive spin on today's weather update. Hey, I'm in the mood for Minnesota Wild hockey! Bug & humidity season has been delayed until further notice. No springy weather to distract me from the stack of work in my weather-cubicle. And farmers are breathing a collective sigh of relief. The drought is dead, a million dollar rain event.

Pete Boulay at the State Climate Office logged 5.45 inches of rain in the Twin Cities as of 1 PM yesterday, making this the 4th wettest April on record, to date. The wettest April? 7 inches fell in 2001. Let's go for a record and add a few new lakes while we're at it!

Welcome to the coldest day of the week. The same stalled storm pumping tropical moisture into Minnesota is also yanking chilly air out of Canada. It may be cold enough for wet snow to mix in with the rain at times today into tonight; maybe a slushy inch or two on lawns and dazed robins north of the MSP metro area. Deep breaths.

Another inch of rain falls before the sun peeks out Friday - more showers arrive by Saturday night. Yes, the overall pattern looks cool & wet.

Too chilly for tornadoes. Did I mention that?

Please wake me when spring arrives.

* Jon Howard took the photo above at the Elm Creek bike trail, which is on the border of Maple Grove & Champlin.

Ranking of April Precipitation from 1871 to 2014
Minneapolis-St Paul Area (MN)

Year Value Rank
2001  7.00"   1
2006  5.97"   2
1986  5.88"   3
2014  5.45"   4 (through 1pm April 28)

* thanks to Pete Boulay at the Minnesota Climatology Working Group for providing me with an update.

Slushy Possibilities. My weather-whining muscles are exhausted. I'm beyond disgusted, entering a realm of reluctant acceptance. Nothing we can do about it - may as well go for weather-boasting-rights now. HAMweather maps (NOAA NAM) show a potential for a couple inches of slushy accumulation over central and southern Minnesota, an arc of 1-3" amounts possible from near Duluth to St. Cloud, Willmar and Mankato by Wednesday morning.

Retrograding Storm. Future Radar shows a nearly stationary storm pinwheeling waves of moisture across the Great Lakes into Minnesota, the atmosphere marginally cold enough for wet snow to mix in at times today and tonight. On the 29th day of April. Severe storms rumble across the Deep South, the western third of the nation dry and mild. NAM model data: HAMweather.

* Flood Watch on the Mississippi River downriver from Winona and La Crosse. With more heavy rain high water levels may rise within 1 foot of flood stage in the coming days. Details here.

Stunted Spring. There's a chance we won't get out of the 30s today with a rainy, snowy, sleety mix much of the day, sustained winds blowing at 20-25 mph. More like February 29 than April 29. Rain Wednesday tapers to showers Thursday. The sun peeks out Friday, and 50s will feel reasonable this weekend, even a shot at 60F by Tuesday of next week. Circle your calendar.


Severe Holding Pattern. The same stalled storm responsible for persistent rain (and some wet snow) from the Great Lakes into the Midwest and Dakotas will spawn another severe weather outbreak later today - a moderate risk of storms over eastern Mississippi and much of Alabama implies another threat of large, violent tornadoes - in pretty much the same area that was impacted Monday. Source: NOAA SPC.

This Is What It Looks Like On The Ground In Arkansas Right Now. Esquire has an update, and a few Vine animated GIFS, one in particular that shows how critical it can be to have a safe room on your property: "A string of tornados ripped through Arkansas, Iowa, and Oklahoma last night, killing at least 18 people and destroying homes, cars, shopping malls, and anything else in its wake. Here are five vines that capture the devastation on the ground in Vilonia, Arkansas."

Photo credit: Danny Johnston, Associated Press.

* tornado survivors in Mayflower, Arkansas recount their terrifying ordeal, courtesy of NBC News.

Debris At 15,000 Feet? Ari Sarsalari tweeted out this Doppler-derived 3-D slice of the atmosphere above Vilonia, Arkansas Sunday evening, apparently showing debris lofted nearly 3 miles into the atmosphere by the massive tornado that pushed north of Little Rock.

Tupelo Velocity Couplet. I snapped this image yesterday (using GR3), a display of SRV, or Storm Relative Velocity, showing 70-90 knots of winds going in either direction around the north side of Tupelo, Mississippi. This is what Doppler radar does, calculating the speed of rain drops and hailstones, either toward or away from the radar site, and deriving areas of spinning "supercell" mesocyclones, the rapidly rotating thunderstorms most likely to spin up tornadoes.

Wedge. Here is a frame-grab from a video of the Tupelo tornado, a massive "wedge tornado" that struck Monday afternoon, leaving behind extensive damage and numerous injuries, but (almost miraculously) no reports of fatalities as of late last night. Today's edition of Climate Matters includes amazing video of the tornado, along with explanations of "debris balls" and "PDS Tornado Watches".

Extreme Tornado Swings: What Holds The Key. Up until Sunday the USA was experiencing one of the quietest starts to tornado season in recorded history. That said, after the events of the last 48 hours it would be wildly premature to get too complacent about tornado season. Here's a clip from Climate Central: "...But while they can chart the tornado numbers, Carbin and his colleague Harold Brooks have “no explanation” for what’s behind this wild swing in tornado activity in just a handful of years. That hasn’t stopped them from looking for one, though, including the possibility that climate change is playing an unrecognized role. “We’ve been scratching our heads for awhile on what is driving this extreme sort of behavior,” Carbin said..."

Image credit above: "An aerial photograph of the damage to Tuscaloosa, Alabama, in the vicinity of the intersection of 15th St. E. and McFarland Blvd. E., wrought by one of the tornadoes that struck the area on April 27, 2011." Credit: NOAA.

Nighttime Tornadoes. The Ohio Valley and Mid South sees a high percentage of tornadoes at night, which is problematic. Tornadoes are much harder to track by spotters east of the Mississippi River (more hills, highway system not on a grid) and at night spotters and chasers have to literally rely on lightning strikes to confirm a tornado on the ground. Source: NOAA SPC.

Hurricane Center Improves Hurricane Intensity Predictions. One of the biggest challenges in meteorology is predicting hurricane intensity, days in advance. Historically forecasting hurricane tracks have more skill than intensity. NOAA took more steps in the right direction last year, as SunSentinel reports - here's a clip: "...Also boosting intensity forecast accuracy, a computer model called the HWRF showed significant improvement after being upgraded halfway through last year's season. The main upgrade: Its resolution was increased, allowing it to see more detail in the atmosphere and better analyze the structure of storms. "The improvement in the HWRF was a big deal," Franklin said. "It gives us some hope for when we have a tougher year." Meanwhile, the center's forecast track errors last year were considerably larger than those in 2012 in almost every forecast period. Franklin attributed that to so many systems being weak..."

El Nino Risk Increases As Pacific Gets Warmer. Bloomberg has an update on the impending El Nino warm phase. At least for Minnesotans it can't come fast enough. Here's a clip: "The odds are increasing that an El Nino weather system will form this year, portending drought for Australia and Asia and a warmer winter in the U.S. Northeast. The U.S. Climate Prediction Center now says there’s a 65 percent chance the Pacific Ocean warming pattern will develop after August. It put the odds at 52 percent last month. The Australian Bureau of Meteorology, which expected neutral conditions at the start of the year, says the phenomenon may start as soon as July. The World Meteorological Organization of the United Nations sees an El Nino at midyear..."

* NOAA has all the ENSO/El Nino details you need to know here.

A Significant El Nino Brewing? Here's an excerpt from the Australian Bureau of Meteorology that made me do a double-take: "All international climate models surveyed by the Bureau indicate that SSTs in the equatorial Pacific Ocean are likely to continue to warm into winter. All models indicate that the equatorial Pacific is likely to exceed El NiƱo thresholds by the southern hemisphere spring, with six of seven models expecting this to occur by July."

The Explosive Growth of California's Drought in 1 Chart. Climate Central has the story - here's the introduction: "It didn’t seem possible, but California's drought just got worse. On Thursday, the U.S. Drought Monitor released new data that show every single inch of the state is now experiencing some form of drought. Since mid-March, a sliver of California on its southeastern border was the lone drought holdout for the state. Even then, that section of the state was still considered abnormally dry according to the Drought Monitor. The section finally tipped into drought this week, and for the first time in 15 year-history of the Drought Monitor, the entire state is now in drought..." (Image: U.S. Drought Monitor).

10 Breakthrough Technologies: 2014. MIT Technology Review lists some of the innovations and technologies making news and disrupting established industries in 2014; here's a clip: "Technology news is full of incremental developments, but few of them are true milestones. Here we’re citing 10 that are. These advances from the past year all solve thorny problems or create powerful new ways of using technology. They are breakthroughs that will matter for years to come."

Yes, It Appears Money Can Buy You Happiness. Buying "stuff", material items, doesn't generate the long-lasting happiness that a purchase of something that brings you closer to friends or family can, research suggests. Here's an excerpt of a Marketplace story that caught my eye: "...Dr. Ryan Howell, associate professor of psychology at San Francisco State University, studies the connection between money and happiness. His research tries to answer, "Can people spend their money to make themselves happier?" And yes, he says, money can buy happiness. "Your discretionary money, if it's spent on bringing you closer to your friends and family [or] if it's spent building up psychological needs, it can make you happy," Howell says. Experiential purchases such as vacations, ball games, and concerts, offer a sense of happiness that, in hindsight, people say they don't feel when purchasing material goods..."

Up Close On Baseball's Borders. The New York Times created a fascinating series of interactive maps that any baseball fan will absolutely want to explore. Here's an excerpt: "...We’ve created two features to help readers explore the data. First is an interactive map of the United States that allows you to explore not just the most popular team in your neighborhood but also a table of the top teams for any ZIP code in the country. Second, in the spirit of Mr. Rushin’s Munson-Nixon line, we've generated 14 maps detailing baseball’s biggest rivalries, highlighting the borders and offering suggested names for those lines..."

Here Comes The Self-Cleaning Car? Uh oh, my car wash investments may be in serious trouble, as reported at Gizmag: "Nissan is currently testing out a prototype that it says could make car washes a relic of the past. The test car benefits from a new nano-paint treatment that repels dirt and grime. The automaker is putting the car through the dirty wringer to see how well it holds up in the real world..."



Climate Stories...

Will Global Warming Produce More Tornadoes? The (scientific) jury is still out; the prevailing wisdom has been that any increase in instability/CAPE would be offset by less wind shear, as northern latitudes warm faster than lower latitudes. But recent research is calling everything into question. Here's an excerpt of a story from Chris Mooney at Mother Jones: "...That conclusion fell into question late last year, though, with a paper by Diffenbaugh and two colleagues in the Proceedings of the National Academy of Sciences. Using a suite of the most state-of-the-art climate models, the researchers found, once again, that wind shear decreases under global warming. However, they also found that that didn't really matter, because the number of days with both high CAPE and high shear nonetheless increased. "We find that in fact, at the monthly or seasonal scale, that decrease [in shear] does occur over the US," Diffenbaugh says, "but it's concentrated in these days with very low CAPE." That means that the net number of days with high CAPE and high shear was still projected to increase in the future..."

Photo credit above: "An automobile dealer surveys the tornado damage to one of his trucks in Mayflower, Arkansas, on Sunday." .

Climate Change, El Nino, Cold Winters, and California's Drought. Does climate volatility have a role in the California drought, or the odd and persistent permutations that parked the Polar Vortex over the USA for the better part of 3 months? Here's a clip from a story at Ars Technica: "...The detours of the jet stream were large, and they were persistent. The northward-bending “ridge” shielded the West Coast from moisture-bearing weather that would normally water the Californian landscape and restock the supply of mountain snow that provides meltwater over the dry summer. Many wondered if climate change could be partly responsible—a question that gets asked about every extreme now. It is, as always, a difficult question to answer, considering the inherent and substantial variability of weather. However, it’s also plainly true that average atmospheric conditions have changed over the past century. The hard part is teasing out the contribution of those changing conditions to specific weather events..."

Graphic credit above: "Vegetation growth for late January 2014. Brown is below average; green is above average. The green areas in the Sierra Nevada mountains would normally be covered in snow at this time of year". NASA Earth Observatory/Jesse Allen

The Koch Attack On Solar Energy. Yes, by all means let's tax the sun. Because it's free and you can't put a meter on it. Here's a clip from a recent New York Times Op-Ed: "At long last, the Koch brothers and their conservative allies in state government have found a new tax they can support. Naturally it’s a tax on something the country needs: solar energy panels. For the last few months, the Kochs and other big polluters have been spending heavily to fight incentives for renewable energy, which have been adopted by most states. They particularly dislike state laws that allow homeowners with solar panels to sell power they don’t need back to electric utilities. So they’ve been pushing legislatures to impose a surtax on this increasingly popular practice, hoping to make installing solar panels on houses less attractive..."

Climate Change: How To Talk About Bad News. More data, more evidence doesn't always convince skeptics, as pointed out in this article at marketplace.org; here's an excerpt: "...Focus on the benefits,” Webber says. Scare campaigns work extremely well when there’s a simple thing you can do to remove the danger. But if it takes protracted action, over time, nobody wants to feel bad for that length of time. People just tune out.” The real challenge, however, may be to talk about climate change in ways that don’t push people’s cultural and political buttons. Dan Kahan’s research shows that the way people view climate change is closely tied to their values.  People “aggressively filter” information that doesn’t conform to their worldview.  “And remarkably the more proficient somebody is at making sense of empirical data," he says, "the more pronounced this tendency is going to...”

Water In Our Shoes. Here's an excerpt of an Op-Ed from The Miami Herald, at ground zero when it comes to rising sea level. South Florida is truly on the front lines of a more volatile, rapidly changing climate: "For South Floridians, the topics of climate change and rising sea levels are no longer to be dismissed as tree-hugger mumbo-jumbo. Pause next time you hear that parts of Miami Beach or the intersection of A1A and Las Olas Boulevard have flooded because of … high tides? Let the light go off atop your head: It’s science, stupid. On Tuesday, Florida Democratic U.S. Sen. Bill Nelson brought illumination to Miami Beach — Ground Zero for our unique coastal battle with Mother Nature..." (Image: NASA).

What Does Today Owe Tomorrow? Justin Gillis at The New York Times examines the issue of legacy, our collective responsibilities for future generations. How do economists assess the risk and what should be done to limit impact? Here's an excerpt: "...Their analyses tend to suggest that, because we have dawdled so long, the economic damage from climate change is going to be substantial, no matter what we do from here. They also generally find that this damage is likely to be dwarfed by bigger economic trends unrelated to climate, like the evolution of technology and shifts in population. Despite those findings, the typical economic analysis suggests that it is still worth trying to limit climate change — in other words, not only can the damage be reduced somewhat, but the future benefits of doing so outweigh the current costs..."

"Green Is Resilience". An article at emissourian.com caught my eye - climate scientists talking to very conservative audiences in central Missouri. Here's an excerpt: "...I would suggest my free market colleagues, especially conservatives, who think that climate change is a bunch of hooey, the Chinese do not. They plan on eating our lunch this next century. They plan on innovating around the problem and selling to us and the rest of the world the technology that will lead the 21st century. “We may press the pause button in America trying to figure out what to do, but China is pressing the fast forward button.”

Climate Change Survival: Companies Need Courage...And New Metrics. The smart companies will go on offense and not wait to make their facilities and processes more resilient and storm-proof. Here's an excerpt from The Guardian: "...Conservative, in this case, essentially means conserving resources to ensure long-term security. In my brother's case, from the time he became aware of the coming crisis, there was no "business as usual" in anything he did: he took emergency measures to protect his company, his workers and his future. And it worked. Many companies are looking beyond sustainability to survivability in their radical approaches to environmental issues. KPMG calculated that the environmental degradation caused by the world's 3,000 largest public companies totaled $2.15tn in 2008. This estimate undoubtedly antagonized many of the company's biggest clients..." (Image: Shutterstock).


Read more here: http://www.miamiherald.com/2014/04/23/4076473/water-in-our-shoes.html#storylink=cpy
How Climate Change Makes Everest An Even Deadlier Game. Grist has a few details and findings I wasn't aware of; here's an excerpt: "...On Everest, it’s as simple as this: Snow and ice are the glue that holds the route up the south col together. When that glue melts, things literally start to fall apart. And while scientists say global temperatures have risen .75 degrees C (1.4 degrees F) in the last century, studies show temperatures in the Himalaya have risen at a rate three times that. The avalanche swept through the part of the route that is most prone to temperature-induced deterioration: the Khumbu Icefall. Even within a season on Everest, the route up the icefall is constantly being rearranged, as summer’s approach widens crevasses and breaks off big columns of ice called seracs..." (Image above: Wikimedia Commons).

"The Year Climate Change Closed Everest". The Atlantic has the story.

Sunday, April 27, 2014

Severe Weather, Tornadoes and Flooding Continue...

Soggy Sunday
Jon Howard snapped this picture from the Elm Creek Park Reserve on Sunday, he said the trails were swamped. 


Precipitation Past 7 Days
Radar estimated rainfall over the past 7 days suggests that widespread 1" to 2" of rain has come down along the I-94 corridor, with more precipitation to come.


Sunday's HIGH RISK
The HIGH RISK on Sunday was one of the highest severe risks of the season thus far.


Stormy Sunday
Thanks to @Ryan_Graves33 for this tornado picture near Galena, KS on Sunday


Satellite Sunday
The satellite on Sunday looked quite impressive along a dryline that was setup on the KS and MO border. Thunderstorms at this point were tornado warned 


Radar Sunday
This is what the radar looked like on Sunday as the storms were erupting across the Plains


Impressive Tornado on Radar Near Little Rock
Here was one of the tornadoes via radar on Sunday evening just NW of downtown Little Rock, AR!! In fact, the tornado warning that was in effect for this particular storm was a TORNADO EMERGENCY... this is what the tornado emergency text looked like!


Severe Threat Continues
Look at how slow the storm system is... the loop below from AM Monday to PM Tuesday, the center of circulation moves east about one state; from Nebraska to Iowa. The waterlogged storm system will still be kicking out heavy rain and severe weather through the middle part of the week.


Severe Threat Monday
...LOWER MS VALLEY EWD INTO NRN AL AND MIDDLE TN... WHILE THE PREVIOUS DAYS CONVECTION WILL LIKELY PLAY A ROLE IN DELINEATING THE PRECISE THREAT CORRIDOR...A SW-NE ORIENTED ZONE OF TRAINING SEVERE THUNDERSTORMS IS LIKELY FROM NERN LA ACROSS MS AND INTO NRN AL AND MIDDLE TN. THE STORMS WILL EITHER BE TIED TO THE COLD FRONT...OR AN OUTFLOW BOUNDARY WHICH COULD SPREAD OUT AHEAD OF THE MAIN SLOW MOVING FRONT. REGARDLESS...A VERY MOIST AND UNSTABLE AIR MASS WILL RESIDE AHEAD OF THE COLD FRONT...WITH SHEAR PROFILES QUITE FAVORABLE FOR SUPERCELLS AND TORNADOES. A LONG UPDRAFT RESIDENCE TIME IN THE UNSTABLE AND HIGHLY SHEARED ENVIRONMENT...AS WELL AS RELATIVELY STEEP MIDLEVEL LAPSE RATES SUGGEST STRONG TORNADOES WILL BE POSSIBLE. VERY LARGE HAIL WILL ALSO OCCUR AS WELL AS POTENTIAL FLOODING. THE MOST SIGNIFICANT TORNADO THREAT IS EXPECTED ACROSS MS.


Severe Threat Tuesday


Severe Threat Wednesday


Slow Moving Storm Continues
Here's another view of the storm as it slowly moves east. The loop shows the storm from PM Sunday to AM Thursday. Note that there isn't much movement from west to east. Also, the moisture conveyor belt continues to send moisture north/northwest through this entire time!


5 day Precipitation
According to NOAA's HPC, the 5 day precipitation forecast suggests quite a bit of precipitation yet over the eastern half of the country along with the Midwest. It's a waterlogged storm that doesn't seem to want to quit. Flooding is going to be a real Likelihood with as much rain as some could see through the end of the week. 


Flood Concerns
* FROM MONDAY EVENING THROUGH WEDNESDAY MORNING * RAINFALL AMOUNTS OF NEAR 4 INCHES WITH LOCALLY UP TO 6 INCHES ARE POSSIBLE ACROSS PARTS OF THE CENTRAL AND SOUTHERN TENNESSEE VALLEY AND PLATEAU


Thanks for checking in and have a great week ahead. Don't forget to follow me on Twitter @TNelsonWNTV

Saturday, April 26, 2014

WNTV BLOG: Severe Sunday; Tornado Threat

Rain in the Desert
I'm spending some time with my family in Arizona and what might have been 'normal' to me, was anything but for the locals here in Phoenix. The last time there was measurable rain in Phoenix, AZ was in early March. Temperatures in the 60s also led to several complaints about how cold it was. While my mother (former Minnesotan) looked like she was dressed for a winter Olympic competition, I was in shorts and flip-flops.


Sierra Snow
This was the view from Yosemite National Park in California early AM Saturday after nearly 2ft. of snow came down in parts Sierras since late last week.


Intense Winds
WOW! The 500mb level showed a near 100kt+ wind over southern California on Saturday morning. This type of intense wind will help to make the storm system even stronger over the coming days!


Storm Pushes East
The same storm system that brought rain and snow to places in the west will continue to move slowly into the central part of the country. Heavy rain and severe weather appears to be the main threat going forward through the rest of the weekend/early next week.


Severe Threats Continue
A multi-day severe weather threat continues through early next week as a powerful Pacific storm continues to wobble east. The image below was from Goldboro, NC as our last storm system departed the Eastern Seaboard.


Friday's Storm Reports


2014 Tornado Reports
Thanks to all of the tornado reports in North Carolina on Friday, the 2014 PRELIMINARY tornado reports through April 25th have climbed to 118. According to NOAA's SPC, the 118 PRELIMINARY tornado reports through April 25th is the lowest number of reports the 2005-2014 reports below. Last year saw 226 tornado reports, while in 2012, there were 588 reports.


Strong Pacific Storm Moves Inland...
The loop below from AM Saturday to AM Tuesday shows our latest strong Pacific storm working into the central U.S. with several rounds of severe weather potential.


Severe Threat Sunday
Sunday's severe threat looks quite interesting across the mid-section of the nation. A MODERATE RISK of severe weather has been issued in parts of the middle and lower Mississippi Valley. Hail, high winds and even tornadoes can't be ruled out. Stay aware of the weather situation if you live in these areas Sunday!!

...NEB...IA...NERN KS...NWRN MO... SEVERE STORMS ARE EXPECTED TO FORM BY EARLY AFTERNOON AHEAD OF THE SURFACE LOW. COLD TEMPERATURES ALOFT AND FAVORABLY ORIENTED DEEP-LAYER SHEAR VECTORS ACROSS THE DRYLINE WILL SUPPORT NWD MOVING SUPERCELLS CAPABLE OF LARGE HAIL AND A FEW TORNADOES.
...ARKLATEX INTO SRN MO... STRONG INSTABILITY WILL DEVELOP AHEAD OF THE DRYLINE AS MID TO UPPER 60S DEWPOINTS SURGE NWD AND HEATING OCCURS. DEEP-LAYER SHEAR WILL BE PERFECTLY ORIENTED RELATIVE TO THE DRYLINE FOR DISCRETE SUPERCELLS. GIVEN THE DEGREE OF BOUNDARY LAYER CONFLUENCE AHEAD OF THE DRYLINE...AND STRONG HEATING AND MOISTENING...A PRE-FRONTAL BAND OF SUPERCELLS COULD FORM OVER SRN AR...NRN LA...AND NERN TX. SUPERCELLS WILL INITIALLY BE CAPABLE OF VERY LARGE HAIL...WITH AN INCREASING TORNADO THREAT AS THEY MATURE DURING THE LATE AFTERNOON AND EVENING. SEVERAL STRONG TORNADOES APPEAR POSSIBLE...AND A HIGH RISK COULD BE ISSUED IN SUBSEQUENT OUTLOOKS ONCE CONFIDENCE IN THE BEST CORRIDOR INCREASES.


Monday Severe Threat
The Storm Prediction Center has issued another MODERATE RISK on Monday just east of Sunday's MODERATE RISK area. Monday could feature another day with tornadoes... 

...MIDWEST TO CNTRL GULF COAST...
A PLUME OF 60S SURFACE DEW POINTS WILL BE ESTABLISHED FROM THE WARM FRONT IN THE MIDWEST S/SWWD TO THE WRN/CNTRL GULF COAST AND PERSIST AMIDST STRONG LOW-LEVEL S/SWLYS. ALTHOUGH CONVECTION WILL LIKELY BE ONGOING AT 12Z/MON FROM PARTS OF THE MIDWEST TO MID-SOUTH...ROBUST DIURNAL HEATING SHOULD OCCUR IN CONVECTIVE-FREE AREAS TO SUPPORT AT LEAST MODERATE BUOYANCY OVER MUCH OF THE WARM SECTOR BY AFTERNOON. LOW/DEEP-LAYER SHEAR WILL BE QUITE STRONG OWING TO THE AFOREMENTIONED SPEED MAX. THIS CO-LOCATION WITH THE ESTABLISHED WARM SECTOR YIELDS A LARGE AREA OF ORGANIZED SEVERE POTENTIAL. THE MOST CONCENTRATED CORRIDOR FOR HIGH-END SEVERE RISK APPEARS CENTERED OVER PARTS OF THE LOWER MS VALLEY TO MID-SOUTH. WIDESPREAD STORMS APPEAR PROBABLE DURING THE AFTERNOON...LIKELY EMANATING FROM REGENERATIVE CONVECTIVE CLUSTERS ALONG THE DRYLINE/CONVECTIVE OUTFLOWS. WITH EFFECTIVE SHEAR AOA 50 KT AND SURFACE DEW POINTS INTO THE MIDDLE TO UPPER 60S...SETUP COULD YIELD SEVERAL SUPERCELLS WITH STRONG TORNADOES AND LARGE HAIL...EVOLVING INTO BOWS AND WIDESPREAD DAMAGING WINDS.


Severe Threat Tuesday
..DISCUSSION... THE MULTI-DAY SEVERE WEATHER EPISODE ASSOCIATED WITH THE PERSISTENT UPPER-LEVEL TROUGH OVER THE CNTRL CONUS SHOULD CONTINUE INTO D4/TUE AS THE LAST IN A SERIES OF INTENSE MID-LEVEL SPEED MAXIMA EJECTS THROUGH THE BASE OF THE TROUGH. THIS SHOULD RESULT IN STRONG KINEMATIC FIELDS OVERSPREADING A GULF WARM SECTOR CHARACTERIZED BY 60S SURFACE DEW POINTS. THE BREADTH OF THE WARM SECTOR WILL PROBABLY BE CONFINED BY WIDESPREAD ANTECEDENT CONVECTION ON D3. HOWEVER...GUIDANCE IS FAIRLY CONSISTENT WITH DIURNAL DESTABILIZATION OCCURRING AHEAD OF THE PACIFIC COLD FRONT/EFFECTIVE DRYLINE. THE CAPE/SHEAR COMBINATION APPEARS FAVORABLE FOR HIGHER-END SEVERE RISK FOCUSED FROM THE CNTRL OH VALLEY TO THE CNTRL GULF COAST. OVERALL KINEMATIC FIELDS SHOULD BE IN A WEAKENING STATE ON D5/WED AND BECOME INCREASINGLY DISPLACED FROM GREATER BUOYANCY AS THE FRONT ACCELERATES EWD. NEVERTHELESS...ORGANIZED SEVERE POTENTIAL IS EVIDENT FROM PARTS OF THE CNTRL APPALACHIANS AND MID-ATLANTIC SWD TO THE SOUTHEAST...LIKELY YIELDING EVENTUAL SLIGHT RISK DELINEATION.


Cut-Off Low Develops
The storm system becomes mature early this week. It intensifies so much that it becomes "Cut-off" from the upper level winds. This tends to keep weather systems stagnant. Weather conditions in the eastern two-thirds of the nation through much of the week ahead.


Wet Weather Ahead
According to NOAA's HPC, the 5 day precipitation forecast looks quite wet for a number of locations east of the Rockies. Some spots could wind up with 2" to 5" of rain by the end of next week!


Thanks again for checking in and have a great rest of your weekend and stay safe!