Hoosier Posted April 15, 2012 Share Posted April 15, 2012 Sunday looks like another day with a large area having a severe weather threat, although the overall magnitude could be a bit less than Saturday. Damaging wind looks to be a prominent threat along with hail. Possible area of enhanced tornado threat may be in the upper Midwest, where SPC currently has a moderate risk. Forecast soundings in that area are favorable for tornadoes. Current day 2 outlook: http://www.spc.noaa.gov/products/outlook/archive/2012/day2otlk_20120414_1730.html Link to comment Share on other sites More sharing options...
Hoosier Posted April 15, 2012 Author Share Posted April 15, 2012 21z SREF popped a small 40 area, which I believe is the first time it has shown that for Sunday. Link to comment Share on other sites More sharing options...
wisconsinwx Posted April 15, 2012 Share Posted April 15, 2012 Nice to see this topic in the main thread. Obviously this won't be near the impact of today's severe weather, but the greatest risk will likely be in an area that doesn't normally see Mid-April severe events, the Upper Midwest. WC Wisconsin has been sho wn to be the most unstable area consistently in recent models, with not a lot of CAPE elsewhere, but plenty of shear. DDL might get a view of a supercell or two. Link to comment Share on other sites More sharing options...
CUmet Posted April 15, 2012 Share Posted April 15, 2012 Most of my attention, as most others I'm sure, has been paid towards the Saturday ongoing event, but now that I've started to look at the Sunday setup updates...boy, the trough sure has slowed down and amplified. Still a lot of question marks regarding whether the directional shear will be sufficient further south, but it looks good enough for a discrete tornadic supercell threat for at least across portions of NE IA, SE MN, and WI. Given the magnitude of the low level CAPE, and model trends suggesting a cleared out warm sector for much of the day up there, there will be a substantial tornado risk. I'm thinking the highest threat will be just ahead of the surface low or near the warm front, so around portions of NE IA, SE MN (including the MSP metro area) and west-central WI. Probably deserves at least a 15% hatched risk for tornadoes... Link to comment Share on other sites More sharing options...
Hoosier Posted April 15, 2012 Author Share Posted April 15, 2012 Most of my attention, as most others I'm sure, has been paid towards the Saturday ongoing event, but now that I've started to look at the Sunday setup updates...boy, the trough sure has slowed down and amplified. Still a lot of question marks regarding whether the directional shear will be sufficient further south, but it looks good enough for a discrete tornadic supercell threat for at least across portions of NE IA, SE MN, and WI. Given the magnitude of the low level CAPE, and model trends suggesting a cleared out warm sector for much of the day up there, there will be a substantial tornado risk. I'm thinking the highest threat will be just ahead of the surface low or near the warm front, so around portions of NE IA, SE MN (including the MSP metro area) and west-central WI. Probably deserves at least a 15% hatched risk for tornadoes... Yeah I was thinking the same thing...probably 15% tornado but wouldn't be shocked if they start out with less. Probably a 45% hatched wind given the extremely strong wind fields. Link to comment Share on other sites More sharing options...
Minnesota Meso Posted April 15, 2012 Share Posted April 15, 2012 21z SREF popped a small 40 area, which I believe is the first time it has shown that for Sunday. my thoughts are these...at 21z tomorrow that tornado risk will shift west and show about the same amplitude its showing now, it will shift into WI by about 16/0z and it could be stronger, this system looks to have slowed down a bit per the Nam Link to comment Share on other sites More sharing options...
wisconsinwx Posted April 15, 2012 Share Posted April 15, 2012 my thoughts are these...at 21z tomorrow that tornado risk will shift west and show about the same amplitude its showing now, it will shift into WI by about 16/0z and it could be stronger, this system looks to have slowed down a bit per the Nam However, both the GFS and NAM still have the low going over or just SE of the Twin Cities, so if anything maybe the threat will start in SE Minnesota and NE Iowa and then spread, but I think the Twin Cities are going to be safe, barring continued NW shifting. Link to comment Share on other sites More sharing options...
Hoosier Posted April 15, 2012 Author Share Posted April 15, 2012 However, both the GFS and NAM still have the low going over or just SE of the Twin Cities, so if anything maybe the threat will start in SE Minnesota and NE Iowa and then spread, but I think the Twin Cities are going to be safe, barring continued NW shifting. Highest threat probably just outside of the Twin Cities but I wouldn't say they are safe. Link to comment Share on other sites More sharing options...
andyhb Posted April 15, 2012 Share Posted April 15, 2012 15% sig-hatched tor. DAY 1 CONVECTIVE OUTLOOKNWS STORM PREDICTION CENTER NORMAN OK 0100 AM CDT SUN APR 15 2012 VALID 151200Z - 161200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF IA/MN/WI AND NORTHWEST IL... ...THERE IS A SLGT RISK OF SVR TSTMS FROM EAST TX/ARKLATEX TO THE UPPER MIDWEST/UPPER GREAT LAKES REGION... ...SYNOPSIS... A PROGRESSIVE/YET AMPLIFIED LARGE SCALE PATTERN WILL BE HIGHLIGHTED BY THE EAST-NORTHEASTWARD MIGRATION OF A POWERFUL/EXTENSIVE TROUGH AND ATTENDANT VERY STRONG UPPER JET /130+ KT 250-300 MB/ OVER A LARGE PART OF THE CENTRAL CONUS. AN ASSOCIATED/RELATIVELY STEADY STATE SURFACE LOW IS EXPECTED TO STEADILY PROGRESS NORTHEASTWARD FROM THE CENTRAL HIGH PLAINS EARLY TODAY...AND REACH THE UPPER MS VALLEY/UPPER GREAT LAKES VICINITY LATE TONIGHT. AT THE SAME TIME...A NORTH-SOUTH EXTENSIVE COLD FRONT WILL MAKE A GENERAL EASTWARD PROGRESSION FROM THE CENTRAL/SOUTHERN PLAINS TOWARD MUCH OF THE MS RIVER VALLEY/UPPER GREAT LAKES BY EARLY MONDAY. ...MIDWEST/UPPER MS RIVER VALLEY... EARLY DAY CONVECTION/REMNANT IMPACTS INDUCES SOME UNCERTAINTY...BUT IT NONETHELESS SEEMS LIKELY THAT LOWER 60S F DEWPOINTS WILL SPREAD NORTHWARD INTO THE REGION IN ASSOCIATION WITH A NORTHWARD-MOVING WARM FRONT...AND AHEAD OF A NORTHEASTWARD MOVING SURFACE LOW/COLD FRONT AND PARENT UPPER TROUGH. EVEN WITH AFOREMENTIONED EARLY DAY CLOUD COVER AND PRECIPITATION...REASONABLE CERTAINTY EXISTS THAT AT LEAST A NARROW MODERATELY UNSTABLE/WEAKLY CAPPED WARM SECTOR WILL MATERIALIZE AHEAD OF THE COLD FRONT...WITH MLCAPE TO 1000-1750 J/KG BY AFTERNOON ACROSS IA/NORTHERN MO INTO SOUTHERN MN AND PARTS OF WI/IL. INITIAL SURFACE BASED DEVELOPMENT...WITH A SCATTERED/BROKEN ARCING BAND OF STORMS...SEEMS PROBABLE THIS AFTERNOON NEAR/AHEAD OF THE COLD FRONT ACROSS PORTIONS OF IA/PERHAPS EVEN EXTREME EASTERN NEB INTO SOUTHERN MN. CURRENT THINKING IS THAT THE GREATEST SEVERE CERTAINTY/POTENTIAL CONCENTRATION WILL BE TO THE EAST-NORTHEAST OF THE NORTHEASTWARD ADVANCING SURFACE LOW NEAR WHERE IT INTERSECTS THE WARM FRONT/ADJACENT WARM SECTOR...WITH POSSIBLE OUTFLOW AUGMENTATION AS WELL. ROBUST DEEP LAYER WIND FIELDS...WITH STRONG/ELONGATED LOW LEVEL HODOGRAPHS AND VERY DEEP LAYER SHEAR EASILY ON THE ORDER OF 50+ KT...WILL LIKELY SUPPORT AN INITIAL SEMI-DISCRETE MODE OF FAST NORTHEASTWARD-MOVING SUPERCELLS WITH AN EVOLUTION TO FAST LINE SEGMENTS/BOWS. ACCORDINGLY...ALL SEVERE HAZARDS APPEARS POSSIBLE...INCLUDING THE POSSIBILITY OF TORNADOES...SEVERE HAIL...IN ADDITION TO POSSIBLE SWATHS OF WIND DAMAGE BY LATE AFTERNOON INTO EVENING ACROSS THE UPPER MS VALLEY. TORNADO POTENTIAL /PERHAPS A FEW STRONG/ WILL LIKELY BE HEIGHTENED NEAR/NORTHEAST OF THE SURFACE LOW AND WARM FRONT/PERHAPS RESIDUAL EARLY DAY OUTFLOW. Link to comment Share on other sites More sharing options...
Hoosier Posted April 15, 2012 Author Share Posted April 15, 2012 Link to comment Share on other sites More sharing options...
andyhb Posted April 15, 2012 Share Posted April 15, 2012 Areas like La Crosse look quite dangerous tomorrow. Link to comment Share on other sites More sharing options...
Hoosier Posted April 15, 2012 Author Share Posted April 15, 2012 Areas like La Crosse look quite dangerous tomorrow. Agree...speed shear is very impressive and there should be enough turning especially in northern areas closer to the surface low. Overall we are looking at much less instability than Saturday but that doesn't mean there won't be problems. NAM has consistently shown very healthy 0-3km CAPE co-located with strong shear. In situations where total CAPE isn't very impressive you'd rather have a decent amount in the low levels when it comes to tornadoes. Link to comment Share on other sites More sharing options...
andyhb Posted April 15, 2012 Share Posted April 15, 2012 Yeah, according to the following, discrete supercells would be big trouble tomorrow afternoon/evening... Pretty ridiculous sounding at Eau Claire at 00z from the NAM: Link to comment Share on other sites More sharing options...
Minnesota Meso Posted April 15, 2012 Share Posted April 15, 2012 Highest threat probably just outside of the Twin Cities but I wouldn't say they are safe. I think the Twin Cities metro will be ground zero, it looks like a 120 knt 250mb jet will set up over the warm sector. Just south of there at 500mb expect winds to be around 55knts. To boot according to the NAM (which I like for convection but absolutely hate for winter,) it looks like around 85knt 0-6km sheer at 21z...over theTC metro..I wonder if the ARX area will get dry slotted? Just a thought. Link to comment Share on other sites More sharing options...
Minnesota Meso Posted April 15, 2012 Share Posted April 15, 2012 Yeah, according to the following, discrete supercells would be big trouble tomorrow afternoon/evening... Pretty ridiculous sounding at Eau Claire at 00z from the NAM: I really lilke the area from the TC Metro to points east, like what EAU is showing, I have problems with the ARX area.....Capping issues??? they will far south of the stalling warm front IMO Link to comment Share on other sites More sharing options...
andyhb Posted April 15, 2012 Share Posted April 15, 2012 I really lilke the area from the TC Metro to points east, like what EAU is showing, I have problems with the ARX area.....Capping issues??? they will far south of the stalling warm front IMO i don't think there will be a lot of capping issues, probably the bigger questions would be convective junk from earlier in the day or whether storm mode goes awry. Link to comment Share on other sites More sharing options...
Minnesota Meso Posted April 15, 2012 Share Posted April 15, 2012 i don't think there will be a lot of capping issues, probably the bigger questions would be convective junk from earlier in the day or whether storm mode goes awry. Thanks Andy Link to comment Share on other sites More sharing options...
Hoosier Posted April 15, 2012 Author Share Posted April 15, 2012 lol Andy you may have found the best forecast sounding in the area. Even if MLCAPE ends up around 1000-1500, it may be more than enough for significant tornadoes given what I mentioned before. Link to comment Share on other sites More sharing options...
Hoosier Posted April 15, 2012 Author Share Posted April 15, 2012 I think the Twin Cities metro will be ground zero, it looks like a 120 knt 250mb jet will set up over the warm sector. Just south of there at 500mb expect winds to be around 55knts. To boot according to the NAM (which I like for convection but absolutely hate for winter,) it looks like around 85knt 0-6km sheer at 21z...over theTC metro..I wonder if the ARX area will get dry slotted? Just a thought. It's close. Certainly think southern/eastern portions of the metro would be at greater threat than farther north. Perhaps sort of a dividing zone. Link to comment Share on other sites More sharing options...
andyhb Posted April 15, 2012 Share Posted April 15, 2012 Anytime I see a 540 dm H5 low in April influencing a potential severe threat, the alarm bell begins to go off... Link to comment Share on other sites More sharing options...
phlwx Posted April 15, 2012 Share Posted April 15, 2012 It's close. Certainly think southern/eastern portions of the metro would be at greater threat than farther north. Perhaps sort of a dividing zone. I wouldn't be surprised if wind threat is higher on the north side, tornado threat higher on south side of the cities. NAM hi-res (take it with grain of salt, of course) puts the warm front to about North Branch to Elk River, which pretty much puts the core counties of the MSP metro in the warm sector. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted April 15, 2012 Share Posted April 15, 2012 I wouldn't be surprised if wind threat is higher on the north side, tornado threat higher on south side of the cities. NAM hi-res (take it with grain of salt, of course) puts the warm front to about North Branch to Elk River, which pretty much puts the core counties of the MSP metro in the warm sector. Going to have to watch it close. The Twin Cities is my hometown area, and overall it is relatively small for such a high population. Right now the NAM is just on the edge of the cities...GFS would miss most of the cities with a weaker low and faster moving cold front. Right now the upper low is rather strung out, and DMC spreading eastward across the WCB may have messed with the cyclone development/advection patterns just enough to weaken the system towards something like the GFS. If that is the case, the bigger threat would be into WI across the upper midwest. Interesting to see the 12z guidance. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted April 15, 2012 Share Posted April 15, 2012 FWIW the RUC wraps the low into SW MN similar to the NAM, but it has instability issues. The incredibly steep low level lapse rates as Hoosier mentioned are a definite plus here though. RUC is dry adiabatic in the low levels to almost 700 hpa. Link to comment Share on other sites More sharing options...
phlwx Posted April 15, 2012 Share Posted April 15, 2012 Going to have to watch it close. The Twin Cities is my hometown area, and overall it is relatively small for such a high population. Right now the NAM is just on the edge of the cities...GFS would miss most of the cities with a weaker low and faster moving cold front. Right now the upper low is rather strung out, and DMC spreading eastward across the WCB may have messed with the cyclone development/advection patterns just enough to weaken the system towards something like the GFS. If that is the case, the bigger threat would be into WI across the upper midwest. Interesting to see the 12z guidance. Yeah...it's not an easy call for them...right on the fence on this... Link to comment Share on other sites More sharing options...
WxMidwest Posted April 15, 2012 Share Posted April 15, 2012 What is horrible, is La Crosse's radar is down from what I have heard, it's definitely not picking up the reflectivity in SW Wisconsin like the DVN radar is.... If an outbreak or corridor of severe weather forms in that area, it's going to be bad news. Met's/Chaser's will have to use secondary TV Station radars, surrounding CWA radar, and GOES Sat Map feeds.. Link to comment Share on other sites More sharing options...
WxMidwest Posted April 15, 2012 Share Posted April 15, 2012 50% Pops in Western Wisconsin for SREF's Tornado Ingredients Parameter, wow.... and La Crosse Radar is down... Link to comment Share on other sites More sharing options...
trapperman Posted April 15, 2012 Share Posted April 15, 2012 What is horrible, is La Crosse's radar is down from what I have heard, it's definitely not picking up the reflectivity in SW Wisconsin like the DVN radar is.... If an outbreak or corridor of severe weather forms in that area, it's going to be bad news. Met's/Chaser's will have to use secondary TV Station radars, surrounding CWA radar, and GOES Sat Map feeds.. Yeah, for dual pol upgrade (!) Great timing... Wonder if every echo is going to be warned just because... Link to comment Share on other sites More sharing options...
JoMo Posted April 15, 2012 Share Posted April 15, 2012 What is horrible, is La Crosse's radar is down from what I have heard, it's definitely not picking up the reflectivity in SW Wisconsin like the DVN radar is.... If an outbreak or corridor of severe weather forms in that area, it's going to be bad news. Met's/Chaser's will have to use secondary TV Station radars, surrounding CWA radar, and GOES Sat Map feeds.. Dual-Pol upgrade, they hope to have it back in operation the week of April 16th. (tomorrow) Makes me curious if they could bring it up in case of emergency. Link to comment Share on other sites More sharing options...
JoMo Posted April 15, 2012 Share Posted April 15, 2012 This formed in OK down by Tahlequah: AT 924 AM CDT...DOPPLER RADAR CONTINUED TO INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO LOCATED NEAR CHEROKEE LANDING STATE PARK...MOVING NORTHEAST AT 45 MPH. THIS IS A DANGEROUS STORM WITH STRONG LOW LEVEL ROTATION...A TORNADO IS OCCURRING OR COULD FORM AT ANY TIME. Link to comment Share on other sites More sharing options...
janetjanet998 Posted April 15, 2012 Share Posted April 15, 2012 MESOSCALE DISCUSSION 0546 NWS STORM PREDICTION CENTER NORMAN OK 0925 AM CDT SUN APR 15 2012 AREAS AFFECTED...NERN TX...ERN OK...WRN AR AND SWRN THROUGH SCNTRL MO CONCERNING...SEVERE THUNDERSTORM WATCH 176... VALID 151425Z - 151600Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 176 CONTINUES. SEVERE THUNDERSTORM WATCH 176 WILL LIKELY NEED TO BE REPLACED WITH A TORNADO WATCH BEFORE 16Z. NEW WW WOULD INCLUDE A PORTION OF NERN TX...EXTREME ERN OK...WRN AR INTO SRN MO. SQUALL LINE FROM EXTREME SWRN MO SWWD THROUGH ERN OK AND NERN TX WILL LIKELY CONTINUE ADVANCING EWD THROUGH NERN TX INTO THE LOWER-MID MS VALLEY THIS MORNING INTO THE AFTERNOON. A 50 KT LLJ DEVELOPING SLOWLY NEWD WILL ADVECT SLIGHTLY HIGHER DEWPOINTS NWD WITH TIME. VISIBLE IMAGERY IS SHOWING SOME CLOUD BREAKS...AND AS THE BOUNDARY LAYER WARMS AN AXIS OF 800-1200 J/KG MLCAPE MAY DEVELOP NWD INTO MO. VERY LARGE HODOGRAPHS WILL PERSIST ALONG THE LLJ AXIS JUST EAST OF THE LINE ALONG WITH STRONG EFFECTIVE SHEAR. DESPITE A DOMINANT LINEAR MODE...POTENTIAL WILL REMAIN FOR SOME OF THE STORMS IN THE LINE TO EVOLVE INTO SUPERCELLS. BOWING SEGMENTS ARE ALSO LIKELY. GIVEN FAVORABLE HODOGRAPHS...THE THREAT FOR A FEW TORNADOES IS EXPECTED TO INCREASE AS THE BOUNDARY LAYER DESTABILIZES. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.