Tim from Springfield (IL) Posted March 24, 2016 Share Posted March 24, 2016 SPC has already posted a D4 severe risk for the southern part of this subforum (including S IL, SW IN, W KY at this time) for Easter Sunday (Mar. 27), although most of the action may be in the Mid-South. Also hinting at a possibly active period as March concludes next Wednesday/Thursday: http://www.spc.noaa.gov/products/exper/day4-8/ DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0359 AM CDT THU MAR 24 2016 VALID 271200Z - 011200Z ...DISCUSSION... SEVERE THUNDERSTORMS ARE LIKELY DAY 4/SUNDAY ACROSS PARTS OF THE MID-SOUTH AND TN/OH VALLEYS. AN UPPER TROUGH IS EXPECTED TO SPREAD EAST-NORTHEASTWARD OVER THE SOUTH-CENTRAL/EAST-CENTRAL CONUS ON SUNDAY/MONDAY DAYS 4-5. REGARDING THIS TROUGH...SOME TIMING/PHASING DIFFERENCES EXIST AMONG AVAILABLE GUIDANCE...WITH THE 00Z ECMWF /SLOWER/ CONTINUING TO EXHIBIT GREATER RUN-TO-RUN CONSISTENCY AS COMPARED TO FASTER 00Z GFS/GEFS SOLUTIONS. THIS SYSTEM WILL LIKELY HAVE ACCESS TO SOMEWHAT RICHER LOW-LEVEL MOISTURE AS COMPARED TO THE TROUGH CURRENTLY CROSSING THE SOUTHERN TIER OF THE CONUS...WHILE AMPLE FORCING/STRONG WIND FIELD WILL CONTRIBUTE TO A SEVERE RISK ACROSS THE MID-SOUTH AND TN/OH VALLEYS ON SUNDAY/DAY 4. AT LEAST SOME SEVERE POTENTIAL MAY CONTINUE INTO DAY 5/MONDAY ACROSS PORTIONS OF THE MID-ATLANTIC STATES/CAROLINAS...AND POSSIBLY AS FAR SOUTH AS FL. WHILE THE AFOREMENTIONED GUIDANCE VARIABILITY PRECLUDES A GRAPHICAL RISK DELINEATION...AT LEAST SOME SEVERE THUNDERSTORMS ARE EXPECTED MONDAY. THEREAFTER...AS THE NEXT UPPER TROUGH AMPLIFIES OVER THE WESTERN/NORTH-CENTRAL CONUS...EARLY INDICATIONS ARE THAT SEVERE POTENTIAL WILL INCREASE ACROSS THE CENTRAL/SOUTHERN PLAINS TO MIDWEST AROUND DAYS 7-8 WEDNESDAY/THURSDAY. ..GUYER.. 03/24/2016 Link to comment Share on other sites More sharing options...
Chicago Storm Posted March 24, 2016 Share Posted March 24, 2016 Given the event next week could be better, I'd say have two threads...one for each event. Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted March 24, 2016 Share Posted March 24, 2016 Real nice to have a couple possible severe chances on the horizon. Link to comment Share on other sites More sharing options...
Hoosier Posted March 24, 2016 Share Posted March 24, 2016 More interested in the second system...looks fairly dynamic at this point but we'll have to see if moisture return is good enough for a robust threat. Link to comment Share on other sites More sharing options...
Stebo Posted March 24, 2016 Share Posted March 24, 2016 Given the event next week could be better, I'd say have two threads...one for each event. Yes, the event a week out has a much higher ceiling. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted March 24, 2016 Share Posted March 24, 2016 The 12Z GFS actually had a somewhat decent threat on it on the 31st, Especially for Illinois and Kentucky. Link to comment Share on other sites More sharing options...
andyhb Posted March 24, 2016 Share Posted March 24, 2016 More interested in the second system...looks fairly dynamic at this point but we'll have to see if moisture return is good enough for a robust threat. Yeah, becoming increasingly interested in that period. Pattern recognition would suggest a higher end threat may be on the table and the moisture return looks like it will be at least decent further south (northern extent still very much TBA). Link to comment Share on other sites More sharing options...
PGM Posted March 24, 2016 Share Posted March 24, 2016 Given the event next week could be better, I'd say have two threads...one for each event. Agreed. Next Thursday may be worthy of a thread on the general weather forum. 12z global op has a 970mb low over upMi, trailing cold front, significant mid and upper level shear, large warm sector with dews in the 70s down south (60s in this subforum). This could be very nasty if we see a large area of 2000j/kg+ cape and discrete supercells from Al to Mi. Luckily we are still one week away and things will hopefully change for the better.. Link to comment Share on other sites More sharing options...
andyhb Posted March 24, 2016 Share Posted March 24, 2016 Agreed. Next Thursday may be worthy of a thread on the general weather forum. 12z global op has a 970mb low over upMi, trailing cold front, significant mid and upper level shear, large warm sector with dews in the 70s down south (60s in this subforum). This could be very nasty if we see a large area of 2000j/kg+ cape and discrete supercells from Al to Mi. Luckily we are still one week away and things will hopefully change for the better.. Well yeah... I can see issues right off that bat that would likely prevent that though, such as the ascent from sub tropical jet leading to a washout on Thursday. Link to comment Share on other sites More sharing options...
PGM Posted March 24, 2016 Share Posted March 24, 2016 Well yeah... I can see issues right off that bat that would likely prevent that though, such as the ascent from sub tropical jet leading to a washout on Thursday. I hope so!! Either way, it's gonna be very windy. When was the last time this region has seen a 970mb low? Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted March 24, 2016 Share Posted March 24, 2016 Yeah, the 12Z GFS would have probably one of the most intense synoptic wind events in awhile. Link to comment Share on other sites More sharing options...
Indystorm Posted March 24, 2016 Share Posted March 24, 2016 18z GFS continues to show an intense system for next Thursday in our area. Would expect changes in intensity as we get closer. Wonder what the Euro's take on this is going to be in upcoming days? Link to comment Share on other sites More sharing options...
IllinoisWedges Posted March 24, 2016 Share Posted March 24, 2016 18z GFS continues to show an intense system for next Thursday in our area. Would expect changes in intensity as we get closer. Wonder what the Euro's take on this is going to be in upcoming days? Well, here's the EPS if you were wondering. Link to comment Share on other sites More sharing options...
andyhb Posted March 24, 2016 Share Posted March 24, 2016 18z GFS continues to show an intense system for next Thursday in our area. Would expect changes in intensity as we get closer. Wonder what the Euro's take on this is going to be in upcoming days? 12z Euro was pretty sheared out. 18z GFS shows a scenario that would potentially result in something quite nasty especially in the OV. 983 mb low at 18z in N IL with a west-southwesterly 700 mb jet streak near 90 kts. Link to comment Share on other sites More sharing options...
Stebo Posted March 24, 2016 Share Posted March 24, 2016 How the GFS doesn't have backing of winds with this system I have no idea. Even without the backing of surface winds there are some incredible soundings off the 18z GFS. Link to comment Share on other sites More sharing options...
tornadohunter Posted March 24, 2016 Share Posted March 24, 2016 18z GFS is concerning for Kentucky IMO. If you notice, there is a strong deepening surface low over NW Illinois. Speed Shear looks to be incredible. Good moisture returns with low to mid 60 dew points as far north as South Bend, In and Columbus Ohio. Cape is sufficient given the setup. Sounding over Louisville shows an uncapped environment. Ill definitely be watching this closely. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted March 25, 2016 Share Posted March 25, 2016 18Z GFS would be pretty serious from Kentucky up through Detroit and back to Chicago. Link to comment Share on other sites More sharing options...
nwohweather Posted March 25, 2016 Share Posted March 25, 2016 18z GFS is concerning for Kentucky IMO. If you notice, there is a strong deepening surface low over NW Illinois. Speed Shear looks to be incredible. Good moisture returns with low to mid 60 dew points as far north as South Bend, In and Columbus Ohio. Cape is sufficient given the setup. Sounding over Louisville shows an uncapped environment. Ill definitely be watching this closely. Yeah once you get above that 300 SRH threshold you're good with most springtime CAPE amounts. Impressed with the LCL and LFC heights as well, essentially ground scraping so I can imagine if this verifies you'll have a lot of "the whole mesocyclone is on the ground reports" with the larger tornadoes. 980 millibar low with that kind of LLJ is one hell of a combo, the storm motion speeds are going to be unreal Link to comment Share on other sites More sharing options...
Hoosier Posted March 25, 2016 Share Posted March 25, 2016 How the GFS doesn't have backing of winds with this system I have no idea. Even without the backing of surface winds there are some incredible soundings off the 18z GFS. To already have it spitting out 1000-2000 J/kg CAPE at this distance should sound some alarm bells. Obviously going to have to see how the system evolves but if it's not messy/sheared out, look out. Link to comment Share on other sites More sharing options...
Stebo Posted March 25, 2016 Share Posted March 25, 2016 To already have it spitting out 1000-2000 J/kg CAPE at this distance should sound some alarm bells. Obviously going to have to see how the system evolves but if it's not messy/sheared out, look out. Yeah, that sort of instability on the GFS in March is something you don't see too often. Link to comment Share on other sites More sharing options...
andyhb Posted March 25, 2016 Share Posted March 25, 2016 Yeah once you get above that 300 SRH threshold you're good with most springtime CAPE amounts. Impressed with the LCL and LFC heights as well, essentially ground scraping so I can imagine if this verifies you'll have a lot of "the whole mesocyclone is on the ground reports" with the larger tornadoes. 980 millibar low with that kind of LLJ is one hell of a combo, the storm motion speeds are going to be unreal Slow down. The model agreement really isn't great regarding any sort of scenario like this. We've seen several times recently where this stuff has looked nasty well out and then downtrended. I've been noticing a fair few number of people jump all over these things early with vernacular like "going to be", etc. only to have it go pear-shaped recently. Link to comment Share on other sites More sharing options...
andyhb Posted March 25, 2016 Share Posted March 25, 2016 Lol, only a 450+ mile shift north in the GFS compared to the last run, basically a non-event. Link to comment Share on other sites More sharing options...
Stebo Posted March 25, 2016 Share Posted March 25, 2016 Lol, only a 450+ mile shift north in the GFS compared to the last run, basically a non-event.Went too strong too early. Link to comment Share on other sites More sharing options...
nwohweather Posted March 25, 2016 Share Posted March 25, 2016 Slow down. The model agreement really isn't great regarding any sort of scenario like this. We've seen several times recently where this stuff has looked nasty well out and then downtrended. I've been noticing a fair few number of people jump all over these things early with vernacular like "going to be", etc. only to have it go pear-shaped recently. I know I'm just stating how good of a run that was. Definitely something like that would draw me down to the Louisville area to chase Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
andyhb Posted March 25, 2016 Share Posted March 25, 2016 All four deterministic models tonight are basically a non-event with this trough. Totally shears out as it runs up against the ridge. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted March 25, 2016 Share Posted March 25, 2016 IWX's thoughts: CONFIDENCE IN TIMING/HANDLING OF NEXT PRECIPITATION CHANCE EVENLOWER WITH STRONG LOW CURRENTLY OFF THE ALEUTIAN ISLANDS WILL MOVEINTO THE PACIFIC NW SUNDAY NIGHT AND THEN DIVE INTO THE FOURCORNERS REGION BY TUESDAY AND EVENTUALLY CUTTING OFF INTO MIDWEEK. COULD BE ANOTHER INTERESTING SYSTEM BUT CONFIDENCE IN TIMINGAND IMPACTS TOWARDS THE END OF THE PERIOD WARRANTS HOLDING WITH ATMOST A MID/HIGH CHC POPS WITH PLENTY OF TIME TO MAKE CHANGES. I'm willing to be almost anything the 06Z Run will be alot different. Link to comment Share on other sites More sharing options...
Indystorm Posted March 25, 2016 Share Posted March 25, 2016 06 GFS has a 980 surface low in the Arrowhead country of MN. I expect these models to jump around with location, strength, shear, and moisture issues this far out until we can get adequate sampling. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted March 25, 2016 Share Posted March 25, 2016 18z NAM has 3000 CAPE for Cincinnati The fact that it's even showing this is impressive Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted March 25, 2016 Share Posted March 25, 2016 Regardless of any model data, it seems IWX already has seen the severe potential. ALL THE EXTENDED RUNS HINT AT ANY NUMBER OF SHORT WAVES EJECTING OUT OF THE TROF INTO THE RIDGE LATE MONDAY-WEDNESDAY BEFORE THE COLD POOL DIVES SOUTH INTO THE NORTHERN TIER STATES AND ACROSS THE GREAT LAKES. SHEAR AND INSTABILITY WILL BE BEST LATE WEDNESDAY FOR POTENTIAL THUNDERSTORM DEVELOPMENT. WHILE IT IS TOO EARLY TO DETERMINE SPECIFIC SEVERE POTENTIAL THIS WILL NEED TO BE WATCHED AS WE GET CLOSER. Link to comment Share on other sites More sharing options...
tornadohunter Posted March 26, 2016 Share Posted March 26, 2016 Yep this is a non event Link to comment Share on other sites More sharing options...
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