Tim from Springfield (IL) Posted May 17, 2017 Share Posted May 17, 2017 Might want to add Saturday (May 20) to this thread--SPC doesn't have anything outlined for Saturday yet but ILX begs to differ: .LONG TERM...(Thursday night through Tuesday) ISSUED AT 345 AM CDT Wed May 17 2017 Cold front to push south toward I-70 by midnight Thu night and and south of CWA and into ohio river valley by Friday morning. Some short wave energy interacting with frontal boundary overnight THu night into Friday to increase chances of showers and thunderstorms from sw to ne during that time. highs Friday range from mid to upper 60s northern CWA to the upper 70s in southeast IL. Main upper level low/trof ejects ne from sw into the Midwest on Saturday along with deepening surface low pressure. This to lift front back north across central IL late Fri night and Saturday morning. Showers and thunderstorms look likely during overnight Fri night into Sat and could be some strong to possibly severe storms on Saturday as cold front moves in sat night. Warmer Sat with highs in the low to mid 80s, expect upper 70s far north. Models have trended quicker with bringing drier air east into central IL on Sunday with qpf east of IL river Sunday morning and near Wabash river valley Sunday afternoon, though GFS is slower than ECWMF model with this trend. Weak 1020 mb surface high pressure builds into areas overnight Sunday night into Monday bringing dry and cooler weather. Highs Sunday mostly in the low to mid 70s, then mostly lower 70s on Monday. chances of showers and thunderstorms return to IL river valley overnight Monday night and across area Tue into Wed with highest pops (likely chances) Tue night and Wed. Highs 70-75F on Tue and then mid to upper 60s on Wed with Lawrenceville around 70F as strong upper level trof digs into IL by Wed. Link to comment Share on other sites More sharing options...
The Iceman Posted May 17, 2017 Share Posted May 17, 2017 I think there's a pretty decent chance that the next update brings a moderate risk for Iowa and if not 1300z then I definitely think by 1630z update we'll see it. today may very well end up being more active tornado wise than yesterday despite it not really being hyped by spc. parameters and shear look to be coming together and i dont think destabilization will be an issue as most of the area will be free from this yesterday's leftovers by 10 am at the latest. wind profiles definitely look better than what were in place in yesterday's mod risk area and while we won't see the high cape values like yesterday, there should be more than enough for sufficient instability. things look to get going at around 18z so it could be a busy afternoon. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted May 17, 2017 Share Posted May 17, 2017 New outlook expands the slight into Chicago Link to comment Share on other sites More sharing options...
OceanStWx Posted May 17, 2017 Share Posted May 17, 2017 Some of the HRRR-TLE products have been spitting out pretty impressive tornado probabilities. Signal has muted a little bit since overnight (probably due to varying model destabilization with cloud cover right now), but I still like NE IA for the best combo of time of day and parameters. Link to comment Share on other sites More sharing options...
The Iceman Posted May 17, 2017 Share Posted May 17, 2017 i like the Waterloo area if i was chasing today. looks like they should see some clearing in the next hour so instability should be no issue. forecast soundings for later look real good in that area too. can't post it though since I'm on mobile. Link to comment Share on other sites More sharing options...
janetjanet998 Posted May 17, 2017 Share Posted May 17, 2017 things should start over southeast NE area here shortly....lots of spin near low may cause some non-supercell spinners then the main arc of storms over IA later..some models want to developing storms over IA/MO and into IL this afternoon too risk may need to be pushed back west a tad in the next update Link to comment Share on other sites More sharing options...
janetjanet998 Posted May 17, 2017 Share Posted May 17, 2017 12z NAM nest and 15z HRRR indicating muiltple lines of distcrete storms ongoing by 22-00z 15z HRRR STP of 10 over N IL by 00z Link to comment Share on other sites More sharing options...
janetjanet998 Posted May 17, 2017 Share Posted May 17, 2017 still no upgrade..and no hatching of any kind DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1120 AM CDT WED MAY 17 2017 VALID 171630Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF IA...SOUTHEAST MN...SOUTHWEST WI...AND SMALL PARTS OF NORTHWEST IL AND NORTHERN MO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE ENH RISK AREA... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE ENH AND SLGT RISK AREAS...AND EXTENDING SOUTHWARD ACROSS THE OZARKS AREA... ..SUMMARY SEVERE STORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON FROM THE MID MISSOURI VALLEY INTO WISCONSIN. A FEW TORNADOES, LARGE HAIL, AND STRONG WIND GUSTS ARE POSSIBLE. FARTHER SOUTH, AT LEAST A MARGINAL SEVERE RISK WILL EXTEND SOUTH ACROSS SOUTHERN MISSOURI AND POSSIBLY INTO ARKANSAS. ..SYNOPSIS WHILE RIDGING ALOFT PERSISTS ACROSS THE EASTERN U.S. THROUGH THE PERIOD, A LARGE/LONG-WAVE TROUGH WILL RESIDE OVER THE WESTERN AND CENTRAL PORTIONS OF THE COUNTRY. THIS TROUGH WILL REMAIN COMPRISED OF TWO MAIN PIECES -- A CLOSED LOW DIGGING SOUTHEAST ACROSS THE INTERMOUNTAIN WEST, AND SECOND/WEAKER LEAD LOW AND ASSOCIATED NEGATIVELY TILTED SHORT-WAVE TROUGH, MOVING QUICKLY NORTHEASTWARD OUT OF THE CENTRAL PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AREA. AT THE SURFACE, A LOW -- NEARLY CO-LOCATED WITH THE CENTER OF UPPER CIRCULATION CURRENTLY CROSSING CENTRAL KANSAS PER WV LOOP -- IS EXPECTED TO MOVE NORTHEAST ACROSS THE MID-MISSOURI VALLEY INTO IA THIS AFTERNOON, AND THEN INTO THE UPPER GREAT LAKES REGION OVERNIGHT. TRAILING SOUTH FROM THE LOW, A WEAKENING BAROCLINIC ZONE WILL SHIFT ACROSS KANSAS INTO IOWA/MISSOURI THROUGH THE AFTERNOON, WITH BANDS OF STRONG/SEVERE THUNDERSTORMS DEVELOPING STARTING EARLY THIS AFTERNOON IN ADVANCE OF THIS SYSTEM. ...MID-MISSOURI VALLEY INTO THE UPPER GREAT LAKES, AND SOUTHWARD ACROSS THE OZARKS... THE BACK EDGE OF HIGH-LEVEL WARM-CONVEYOR CLOUD COVER CONTINUES SPREADING QUICKLY NORTHEASTWARD INTO SOUTHWEST IA/WESTERN MO LATE THIS MORNING, WHILE AN OVERALL THINNING OF THE HIGH CLOUDS IS ALSO OCCURRING OVER THE IA/MO VICINITY. AS THIS TREND CONTINUES, RESULTING DIABATIC HEATING COMBINED WITH MID-LEVEL COOLING SPREADING ACROSS THE AREA AS THE UPPER LOW/TROUGH SHIFTS STEADILY NORTHEASTWARD WILL RESULT IN SUBSTANTIAL DESTABILIZATION, WITH 1000 TO 2000 J/KG MIXED-LAYER CAPE BY MID-AFTERNOON CENTERED OVER THE SOUTHERN WI/IA/MO AREA AND VICINITY. WHILE STORM DEVELOPMENT SOUTHWARD TOWARD THE OZARKS REMAINS LESS CERTAIN WITH ASCENT SHIFTING NORTHEASTWARD TOWARD THE UPPER MISSISSIPPI VALLEY WITH TIME, STORM DEVELOPMENT APPEARS TO BE ESSENTIALLY A CERTAINTY -- LIKELY BY EARLY AFTERNOON -- FARTHER NORTH, WITH THE AREA OF MAXIMUM DIURNAL HEATING WITHIN THE DRY SLOT OVER THE SOUTHEAST NE/NORTHEAST KS/NORTHWEST MO/SOUTHWEST IA AREA. OTHER DEVELOPMENT SHOULD -- EITHER SIMULTANEOUSLY OR SHORTLY THEREAFTER -- OCCUR NORTHEASTWARD ACROSS IA AND INTO SOUTHERN MN AND WI. AFOREMENTIONED UNCERTAINTY REGARDING DEGREE OF CONVECTIVE DEVELOPMENT SOUTHWARD ACROSS CENTRAL AND SOUTHERN MO AND INTO AR SUGGESTS MAINTENANCE OF ONLY MRGL RISK ACROSS THIS AREA. STILL, WITH SUFFICIENT DESTABILIZATION EXPECTED AND VERY STRONG FLOW ALOFT TO RESIDE ATOP THE AREA, ANY STORMS WHICH DO FORM WOULD LIKELY POSE A SEVERE RISK -- INCLUDING POTENTIAL FOR LARGE HAIL AND LOCALLY DAMAGING WINDS. FARTHER NORTH IN THE HIGHER-RISK AREA, MULTIPLE BANDS OF STORMS -- BOTH CELLULAR/MIXED-MODE AND POSSIBLY BOWING LINE SEGMENTS -- ARE EVENTUALLY EXPECTED TO EVOLVE AFTER INITIAL CELLULAR DEVELOPMENT. VERY STRONG -- BUT ROUGHLY UNIDIRECTIONAL/SOUTH-SOUTHWESTERLY -- FLOW ALOFT WILL YIELD DEEP-LAYER SHEAR SUPPORTIVE OF WELL-ORGANIZED/ROTATING STORMS, WITH LARGE HAIL AND DAMAGING WINDS LIKELY. RISK FOR A FEW TORNADOES IS ALSO EVIDENT, ESPECIALLY ACROSS THE IA AREA ROUGHLY ALONG THE PROJECTED PATH OF THE SURFACE LOW, WHERE SURFACE FLOW BACKED TO AN EAST-OF-SOUTH DIRECTION WILL ENHANCE LOW-LEVEL SHEAR. A RATHER RAPID EASTWARD/NORTHEASTWARD SHIFT IN STORM ACTIVITY/SEVERE RISK IS EXPECTED, WITH THE STRONGEST CONVECTION SPREADING LARGELY OUT OF IA/MN AND ACROSS WI/UPPER MI/NORTHERN IL THROUGH THE EVENING BEFORE CONVECTION WEAKENS/DIMINISHES LATE THIS EVENING/OVERNIGHT. ..GOSS/CONIGLIO.. 05/17/2017 Link to comment Share on other sites More sharing options...
CoalCityWxMan Posted May 17, 2017 Share Posted May 17, 2017 The new HRRR is pretty interesting for the Chicago area compared to past runs. Link to comment Share on other sites More sharing options...
OceanStWx Posted May 17, 2017 Share Posted May 17, 2017 Looks like (according to SPC mesoanalysis) there is some sort of effective warm front hanging around the Highway 20 corridor in IA. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted May 17, 2017 Share Posted May 17, 2017 MD just issued, Tornado Watch inbound MESOSCALE DISCUSSION 0747 NWS STORM PREDICTION CENTER NORMAN OK 1139 AM CDT WED MAY 17 2017 AREAS AFFECTED...NORTHEAST KS...SOUTHEAST NE...NORTHWEST MO...IA CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 171639Z - 171745Z PROBABILITY OF WATCH ISSUANCE...95 PERCENT SUMMARY...SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP AHEAD OF A MIGRATORY LOW IN NORTHEAST KS, THEN SPREAD INTO IA. ISOLATED TORNADOES ARE EXPECTED ALONG WITH LARGE HAIL AND DAMAGING WINDS. DISCUSSION...EXIT REGION OF STRONG MID-LEVEL JET IS RAPIDLY SPREADING ACROSS NORTHEAST KS LATE THIS MORNING. AS 90KT+ 500MB SPEED MAX TRANSLATES INTO NORTHWEST MO BY 18Z LARGE-SCALE FORCING FOR ASCENT WILL SHIFT INTO IA. MID-HIGH LEVEL CLOUDINESS HAS CLEARED NICELY AHEAD OF THIS FEATURE AND STRONG BOUNDARY-LAYER HEATING IS OBSERVED AHEAD OF THE SURFACE LOW. DIAGNOSTIC DATA SUGGESTS SURFACE-3KM LAPSE RATES ARE NOW IN EXCESS OF 8 C/KM ACROSS NORTHEAST KS AND FURTHER STEEPENING IS EXPECTED ALONG A CORRIDOR EXTENDING INTO IA AS HIGH CLOUDS CLEAR. LATEST VISIBLE SATELLITE IMAGERY SUGGESTS BOUNDARY-LAYER CU FIELD IS THICKENING IMMEDIATELY AHEAD OF SURFACE DRYING FROM EASTERN KS, ARCING TOWARD SOUTHEAST NE. WHILE DEEP CONVECTION IS EVOLVING ALONG THE TRAILING COLD FRONT, LATEST THINKING IS DISCRETE SUPERCELLS WILL EVOLVE AHEAD OF THE FRONT THEN TRACK NORTHEAST INTO AN INCREASINGLY BUOYANT AIR MASS. ISOLATED TORNADOES ARE EXPECTED, ALONG WITH HAIL AND WIND. Link to comment Share on other sites More sharing options...
Hoosier Posted May 17, 2017 Share Posted May 17, 2017 Look no further than the widespread wind advisories as an indication of the strong background fields, which is not the easiest thing to do in May. Link to comment Share on other sites More sharing options...
Hoosier Posted May 17, 2017 Share Posted May 17, 2017 15 minutes ago, CoalCityWxMan said: The new HRRR is pretty interesting for the Chicago area compared to past runs. Brings some activity in around 21z-22z. If it's right, probably going to have T/Td spreads a bit too high for a better tornado threat. Link to comment Share on other sites More sharing options...
Jim Martin Posted May 17, 2017 Share Posted May 17, 2017 Tornado Watch Forthcoming. Link to comment Share on other sites More sharing options...
OceanStWx Posted May 17, 2017 Share Posted May 17, 2017 That area just SW of DSM is a nice little environment for this early convection. Link to comment Share on other sites More sharing options...
The Iceman Posted May 17, 2017 Share Posted May 17, 2017 Quote URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 231 NWS Storm Prediction Center Norman OK 1205 PM CDT Wed May 17 2017 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of much of western and central Iowa parts of northeast Kansas portions of northern Missouri parts of eastern Nebraska * Effective this Wednesday afternoon and evening from 1205 PM until 700 PM CDT. * Primary threats include... A few tornadoes and a couple intense tornadoes possible Isolated very large hail events to 2 inches in diameter possible Isolated damaging wind gusts to 70 mph possible SUMMARY...Thunderstorms have begun to develop early this afternoon across parts of north-central Kansas and into the mid-Missouri Valley area, and should continue expanding/spreading northeast across the WW area over the next several hours. Large hail and locally damaging winds will be possible, along with a few tornadoes this afternoon and into the early evening hours. 50/30 tor probs Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted May 17, 2017 Share Posted May 17, 2017 New watch mentions intense tornadoes URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 231 NWS Storm Prediction Center Norman OK 1205 PM CDT Wed May 17 2017 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of much of western and central Iowa parts of northeast Kansas portions of northern Missouri parts of eastern Nebraska * Effective this Wednesday afternoon and evening from 1205 PM until 700 PM CDT. * Primary threats include... A few tornadoes and a couple intense tornadoes possible Isolated very large hail events to 2 inches in diameter possible Isolated damaging wind gusts to 70 mph possible SUMMARY...Thunderstorms have begun to develop early this afternoon across parts of north-central Kansas and into the mid-Missouri Valley area, and should continue expanding/spreading northeast across the WW area over the next several hours. Large hail and locally damaging winds will be possible, along with a few tornadoes this afternoon and into the early evening hours. Link to comment Share on other sites More sharing options...
Jim Martin Posted May 17, 2017 Share Posted May 17, 2017 First Tornado Watch of the day. Link to comment Share on other sites More sharing options...
Stebo Posted May 17, 2017 Share Posted May 17, 2017 35 minutes ago, OceanStWx said: Looks like (according to SPC mesoanalysis) there is some sort of effective warm front hanging around the Highway 20 corridor in IA. If I were out there today, that would be my zone of play. Link to comment Share on other sites More sharing options...
OceanStWx Posted May 17, 2017 Share Posted May 17, 2017 Just now, Stebo said: If I were out there today, that would be my zone of play. In the NWS forecast contest I placed my target at Jesup, IA. A sliver NE of this watch, but we also don't start scoring until 19z (it's meant to hone mesoanalysis so morning stuff doesn't count). Link to comment Share on other sites More sharing options...
Stebo Posted May 17, 2017 Share Posted May 17, 2017 Just now, OceanStWx said: In the NWS forecast contest I placed my target at Jesup, IA. A sliver NE of this watch, but we also don't start scoring until 19z (it's meant to hone mesoanalysis so morning stuff doesn't count). Sounds like a fun contest to be honest Link to comment Share on other sites More sharing options...
OceanStWx Posted May 17, 2017 Share Posted May 17, 2017 2 minutes ago, Stebo said: Sounds like a fun contest to be honest Well for a full blooded severe weenie it's great, I'll admit. But it does really help for WFOs that have infrequent severe. You can spin yourself up on events across the country before you actually have to deal with it at home. It's not just tornadoes either. You have to pick the report type (hail, wind, tornado) otherwise you don't score as many points. Link to comment Share on other sites More sharing options...
Stebo Posted May 17, 2017 Share Posted May 17, 2017 Just now, OceanStWx said: Well for a full blooded severe weenie it's great, I'll admit. But it does really help for WFOs that have infrequent severe. You can spin yourself up on events across the country before you actually have to deal with it at home. It's not just tornadoes either. You have to pick the report type (hail, wind, tornado) otherwise you don't score as many points. Yeah that really sounds awesome and yeah would make sense, because most NWS mets don't stay in one place. Would be good to get practice in if you are in Maine in case you move next to Wichita for example. That really is a proactive approach by the NWS. Link to comment Share on other sites More sharing options...
andyhb Posted May 17, 2017 Share Posted May 17, 2017 Cell S of Manning, IA is already rotating a decent amount. Link to comment Share on other sites More sharing options...
OceanStWx Posted May 17, 2017 Share Posted May 17, 2017 Just now, Stebo said: Yeah that really sounds awesome and yeah would make sense, because most NWS mets don't stay in one place. Would be good to get practice in if you are in Maine in case you move next to Wichita for example. That really is a proactive approach by the NWS. It was my suggestion up through the ranks of the NWS, after messing around with some similar contests on message boards like this one. It's helped me immensely. Things will move fast today, and with lower end CAPE and high shear updrafts may be very tilted, but with 0-1 km shear so high some of the quick tornadoes could be significant. Link to comment Share on other sites More sharing options...
Stebo Posted May 17, 2017 Share Posted May 17, 2017 Just now, OceanStWx said: It was my suggestion up through the ranks of the NWS, after messing around with some similar contests on message boards like this one. It's helped me immensely. Things will move fast today, and with lower end CAPE and high shear updrafts may be very tilted, but with 0-1 km shear so high some of the quick tornadoes could be significant. Honestly this type of setup reminds me a bit like a October/November setup but with a bit more CAPE. Link to comment Share on other sites More sharing options...
OceanStWx Posted May 17, 2017 Share Posted May 17, 2017 9 minutes ago, andyhb said: Cell S of Manning, IA is already rotating a decent amount. Mini supercell, pushing 40 kft but the bulk of the echo below 30, so definitely a higher shear/lower CAPE look. Link to comment Share on other sites More sharing options...
indeedinger Posted May 17, 2017 Share Posted May 17, 2017 20 minutes ago, OceanStWx said: In the NWS forecast contest I placed my target at Jesup, IA. A sliver NE of this watch, but we also don't start scoring until 19z (it's meant to hone mesoanalysis so morning stuff doesn't count). I live 10 miles due east of Jesup. Giddy up . . . Link to comment Share on other sites More sharing options...
Hoosier Posted May 17, 2017 Share Posted May 17, 2017 Gil's take http://weather.admin.niu.edu/forecast.txt Link to comment Share on other sites More sharing options...
Jim Martin Posted May 17, 2017 Share Posted May 17, 2017 Risk for severe thunderstorms Thursday across Northeast Indiana & Northwest Ohio. Damaging Wind/Large Hail risk. Link to comment Share on other sites More sharing options...
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