Tim from Springfield (IL) Posted July 22, 2015 Share Posted July 22, 2015 Not sure if this is too premature to start a thread for this weekend's severe threat in at least part of the subforum, but after reading the short term thread and this morning's SPC outlooks, here goes: http://www.spc.noaa.gov/products/exper/day4-8/ DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0357 AM CDT TUE JUL 21 2015 VALID 241200Z - 291200Z ...DISCUSSION... PER 00Z/JULY 21 GUIDANCE CONSENSUS...IT SEEMS LIKELY THAT A LOW-AMPLITUDE SHORTWAVE TROUGH IN THE NORTHERN STREAM WILL CONTINUE TO AMPLIFY OVER THE INTERNATIONAL BORDER/UPPER MIDWEST ON DAY 4/FRIDAY...WITH A COLD FRONT SPREADING EAST-SOUTHEASTWARD ACROSS THE UPPER MIDWEST/CORN BELT. WHILE THE POTENTIAL FOR A THURSDAY NIGHT/EARLY FRIDAY MCS COMPLICATES SOME OF THE SPATIAL DETAILS...IT IS PROBABLE THAT STRONG/SEVERE THUNDERSTORMS WILL REDEVELOP ACROSS THE REGION FRIDAY AFTERNOON/EVENING AHEAD OF THE FRONT. SUFFICIENT INSTABILITY/VERTICAL SHEAR IS EXPECTED TO BE IN PLACE FOR ORGANIZED STORM MODES CAPABLE OF AT LEAST ISOLATED HAIL/WIND ACROSS MUCH OF WI AND POSSIBLY EASTERN MN/NORTHERN IA. FOR DAYS 5/6 SATURDAY AND SUNDAY...THE POTENTIAL FOR SOME STRONG/SEVERE THUNDERSTORMS...MAINLY CAPABLE OF DAMAGING WINDS...IS EXPECTED TO SPREAD EAST-SOUTHEASTWARD INTO PARTS OF THE MIDWEST/OH RIVER VALLEY AND LOWER GREAT LAKES VICINITY AHEAD OF THE EAST/SOUTHEASTWARD-ADVANCING COLD FRONT. ..GUYER.. 07/21/2015 Also going to include Thursday in this thread in case the current D3 slight that includes far W MN gets pulled further east: http://www.spc.noaa.gov/products/outlook/day3otlk.html DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0229 AM CDT TUE JUL 21 2015 VALID 231200Z - 241200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NORTHERN PLAINS... ...THERE IS A MRGL RISK OF SVR TSTMS FROM THE NORTHERN ROCKIES TO THE NORTHERN/CENTRAL PLAINS AND UPPER MIDWEST... ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE SOUTHEAST STATES... ...SUMMARY... SEVERE THUNDERSTORMS WILL BE POSSIBLE MAINLY ACROSS THE NORTHERN PLAINS ON THURSDAY. ...SYNOPSIS... AN AMPLIFYING BELT OF WESTERLIES IS EXPECTED OVER THE NORTHERN THIRD OF THE CONUS ON THURSDAY...WHILE AN UPPER RIDGE REMAINS CENTERED OVER THE SOUTH-CENTRAL CONUS. ...NORTHERN PLAINS AND NORTHERN ROCKIES TO CENTRAL PLAINS... ONE OR MORE MID-LEVEL SHORTWAVE TROUGHS ARE EXPECTED TO CROSS THE REGION...WITH DOWNSTREAM HEIGHT FALLS EXPECTED PARTICULARLY ACROSS ND/NORTHERN SD INTO NORTHERN MN THURSDAY LATE AFTERNOON AND NIGHT. A SURFACE LOW IS EXPECTED TO GRADUALLY DEEPEN ACROSS SD...WHILE A COLD FRONT WILL MOVE EAST-SOUTHEASTWARD ACROSS THE REGION ON THURSDAY AND SERVE AS A FOCUS FOR STRONG/SEVERE THUNDERSTORM DEVELOPMENT THURSDAY AFTERNOON/EVENING...INITIALLY ACROSS PORTIONS OF ND/NORTHERN SD. NEAR THIS FRONT...A MODERATELY UNSTABLE AIR MASS IS EXPECTED TO BE COLLOCATED WITH AROUND 40 KT OF VERTICAL SHEAR...WHICH WILL BE SUPPORTIVE OF SOME SUPERCELLS/WELL-SUSTAINED MULTICELLS CAPABLE OF SEVERE HAIL/WIND AND POSSIBLY A TORNADO. MCS DEVELOPMENT SHOULD SUBSEQUENTLY OCCUR THURSDAY EVENING...LIKELY SPREADING EAST-SOUTHEASTWARD INTO WESTERN/NORTHERN MN DURING THE LATE EVENING/OVERNIGHT HOURS. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted July 22, 2015 Share Posted July 22, 2015 00z GFS continues to have widespread upper 70 dew point this weekend, even some low 80's. For the most part, the wind profile isn't great (it's late July; go figure), but still sufficient for severe storms Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted July 22, 2015 Author Share Posted July 22, 2015 New D3 for Friday: http://www.spc.noaa.gov/products/outlook/day3otlk.html DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0230 AM CDT WED JUL 22 2015 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE UPPER MIDWEST/UPPER MS RIVER VALLEY... ...THERE IS A MRGL RISK OF SVR TSTMS FROM THE CENTRAL HIGH PLAINS TO THE UPPER GREAT LAKES... ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE SOUTHEAST STATES/FL PENINSULA... ...SUMMARY... SEVERE THUNDERSTORMS WILL BE POSSIBLE FRIDAY MAINLY ACROSS PARTS OF THE UPPER MIDWEST. ...SYNOPSIS... MODEST LARGE-SCALE PATTERN DEAMPLIFICATION IS EXPECTED ON FRIDAY AS A LOW-AMPLITUDE BELT OF MODERATELY STRONG WESTERLIES WILL CONTINUE TO PREVAIL OVER THE NORTHERN THIRD OF THE CONUS. ...UPPER MIDWEST/UPPER MS RIVER VALLEY/CENTRAL PLAINS... WEAK HEIGHT FALLS ARE EXPECTED OVER THE UPPER MIDWEST/INTERNATIONAL BORDER VICINITY COINCIDENT WITH A CORRIDOR OF LOW-AMPLITUDE/NEARLY ZONAL WESTERLIES. THUNDERSTORMS ARE EXPECTED TO INCREASE FRIDAY AFTERNOON/EARLY EVENING NEAR A SOUTHEASTWARD-MOVING COLD FRONT ACROSS PARTS OF MN AND NORTHERN/FAR WESTERN WI...AND POSSIBLY PARTS OF THE MIDDLE MO VALLEY...ALTHOUGH CAPPING/MID-LEVEL WARMTH WILL STEADILY INCREASE WITH SOUTHWESTWARD EXTENT ALONG THE ADVANCING FRONT. BOUTS OF SEVERE WIND/HAIL WILL BE POSSIBLE WITH THE STRONGER STORMS PARTICULARLY FRIDAY LATE AFTERNOON AND EVENING. [ . . . ] ..GUYER.. 07/22/2015 Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted July 22, 2015 Author Share Posted July 22, 2015 No risk area yet on the new D4-8 for Saturday and Sunday, although SPC not ruling out some severe for both days. SPC also hinting at a possible risk in the Dakotas/Upper Midwest on Monday/Tuesday: http://www.spc.noaa.gov/products/exper/day4-8/ DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0344 AM CDT WED JUL 22 2015 VALID 251200Z - 301200Z ...DISCUSSION... A LOW-AMPLITUDE/NEARLY ZONAL BELT OF WESTERLIES WILL GENERALLY PREVAIL OVER THE NORTHERN TIER OF THE CONUS...WITH A COLD FRONT EXPECTED TO SETTLE SOUTHEASTWARD ACROSS MUCH OF THE MIDWEST/GREAT LAKES REGION THIS WEEKEND. ALTHOUGH LARGE-SCALE FORCING/VERTICAL SHEAR SHOULD BE MODEST...AT LEAST SOME STRONG/SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS THE UPPER MS VALLEY/CORN BELT ON DAY 4/SATURDAY...AND INTO THE MIDWEST/GREAT LAKES ON DAY 5/SUNDAY. A SOMEWHAT MORE SUBSTANTIAL UPPER TROUGH MAY BEGIN TO CROSS THE NORTHERN CONUS/CANADIAN ROCKIES AROUND DAY 6/MONDAY. THE GENERAL EAST-NORTHEASTWARD PROGRESSION OF THE UPPER TROUGH AND AN INCREASINGLY MOIST DOWNSTREAM AIR MASS MAY LEAD TO A SEVERE RISK ACROSS PARTS OF THE DAKOTAS/UPPER MIDWEST DURING DAYS 6/7 MONDAY/TUESDAY. ..GUYER.. 07/22/2015 Link to comment Share on other sites More sharing options...
Chargers09 Posted July 22, 2015 Share Posted July 22, 2015 I think Sat and Sun could be decent for portions of the subforum. Typical late july risk. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted July 23, 2015 Share Posted July 23, 2015 Day 3 Marginal Risk, Possible Slight Risk Upgrade for Day Two. Link to comment Share on other sites More sharing options...
TimChgo9 Posted July 24, 2015 Share Posted July 24, 2015 Skilling was talking about severe potential for this weekend in a FB post. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted July 24, 2015 Share Posted July 24, 2015 What's not to love about the NAM? This sounding... wtf? Am I really seeing this in late July, really? Link to comment Share on other sites More sharing options...
andyhb Posted July 24, 2015 Share Posted July 24, 2015 What's not to love about the NAM? This sounding... wtf? Am I really seeing this in late July, really? This is almost certainly a convective response with the MCS the NAM is showing in that area and an overly deep surface low in the direct vicinity. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted July 24, 2015 Share Posted July 24, 2015 This is almost certainly a convective response with the MCS the NAM is showing in that area and an overly deep surface low in the direct vicinity. One hell of an MCS 2m theta-e: http://i.imgur.com/lCcVJRl.gif Link to comment Share on other sites More sharing options...
andyhb Posted July 24, 2015 Share Posted July 24, 2015 You can see the convective contamination of that sounding with the moist layer extending all the way up to 750 mb. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted July 24, 2015 Share Posted July 24, 2015 This is almost certainly a convective response with the MCS the NAM is showing in that area and an overly deep surface low in the direct vicinity. Yeah easy to see on this run which is why you're getting the sky high parameters. Wind fields all enhanced Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 24, 2015 Share Posted July 24, 2015 zzzzzzzzz Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted July 24, 2015 Share Posted July 24, 2015 Euro's interesting for early next week... lots of instability Tuesday Link to comment Share on other sites More sharing options...
andyhb Posted July 24, 2015 Share Posted July 24, 2015 Euro's really interesting for early next week... lots of instability Problem with every day after Monday is the strongest flow aloft is severely lagging the effective warm sector due to the system's compact nature and the fact that it is occluding. Deep layer shear over most of the warm sector on Tues/Wed is pretty pitiful. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted July 24, 2015 Share Posted July 24, 2015 Problem with every day after Monday is the strongest flow aloft is severely lagging the effective warm sector due to the system's compact nature and the fact that it is occluding. Deep layer shear over most of the warm sector on Tues/Wed is pretty pitiful. Do you know how much shear there is on the Euro for Tuesday/Wednesday? Link to comment Share on other sites More sharing options...
Thundersnow12 Posted July 24, 2015 Share Posted July 24, 2015 Euro's interesting for early next week... lots of instability Tuesday It's the heart of summer, there's always lots of instability. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted July 24, 2015 Share Posted July 24, 2015 It's the heart of summer, there's always lots of instability. Yeah but 5500+ is still pretty rare. Link to comment Share on other sites More sharing options...
andyhb Posted July 24, 2015 Share Posted July 24, 2015 Do you know how much shear there is on the Euro for Tuesday/Wednesday? 30 kts or less over most of that instability axis. Yeah but 5500+ is still pretty rare. Not really during summer. The day I'd be watching is Monday further west. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted July 24, 2015 Share Posted July 24, 2015 30 kts or less over most of that instability axis. Not really during summer. Don't need much to get an MCS going Euro's showing highs well into the 90's widespread across Iowa, Minnesota and especially places further south. Looks like even triple digits for Minneapolis Metro. I'm about 15 miles north of Cincinnati and 90+ degree days are pretty rare and my average high for July is 88. I'm sure it's even more rare for Iowa and Minnesota to get that warm. ...and yes, I get that the surface temp isn't the only factor in instability. There's moisture (and thus LCL) and lapse rates. MUCAPE climatology: Link to comment Share on other sites More sharing options...
AppsRunner Posted July 25, 2015 Share Posted July 25, 2015 Tornado Warning out in Wisconsin TORNADO WARNINGWIC035-250430-/O.NEW.KMPX.TO.W.0029.150725T0338Z-150725T0430Z/BULLETIN - EAS ACTIVATION REQUESTEDTORNADO WARNINGNATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN1038 PM CDT FRI JUL 24 2015THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A* TORNADO WARNING FOR...EASTERN EAU CLAIRE COUNTY IN WEST CENTRAL WISCONSIN...* UNTIL 1130 PM CDT* AT 1037 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING ATORNADO WAS LOCATED OVER LAKE WISSOTA...OR 8 MILES EAST OF EAUCLAIRE...MOVING SOUTHEAST AT 35 MPH.HAZARD...TORNADO.SOURCE...RADAR INDICATED ROTATION.IMPACT...FLYING DEBRIS WILL BE DANGEROUS TO THOSE CAUGHT WITHOUTSHELTER. MOBILE HOMES WILL BE DAMAGED OR DESTROYED.DAMAGE TO ROOFS...WINDOWS AND VEHICLES WILL OCCUR. TREEDAMAGE IS LIKELY.* THIS DANGEROUS STORM WILL BE NEAR...FALL CREEK AROUND 1050 PM CDT.AUGUSTA AROUND 1105 PM CDT.FAIRCHILD AROUND 1120 PM CDT.OTHER LOCATIONS IMPACTED BY THIS TORNADIC THUNDERSTORM INCLUDELUDINGTON AND LAKE EAU CLAIRE COUNTY PARK.PRECAUTIONARY/PREPAREDNESS ACTIONS...HEAVY RAINFALL MAY HIDE THIS TORNADO. DO NOT WAIT TO SEE OR HEAR THETORNADO. TAKE COVER NOW.TORNADOES ARE EXTREMELY DIFFICULT TO SEE AND CONFIRM AT NIGHT. DO NOTWAIT TO SEE OR HEAR THE TORNADO. TAKE COVER NOW.TO REPORT SEVERE WEATHER CONTACT YOUR NEAREST LAW ENFORCEMENT AGENCY.THEY WILL SEND YOUR REPORT TO THE NATIONAL WEATHER SERVICE OFFICE INTHE TWIN CITIES.&&LAT...LON 4460 9122 4485 9138 4486 9137 4485 91094474 9092 4460 9092TIME...MOT...LOC 0337Z 320DEG 31KT 4488 9127TORNADO...RADAR INDICATEDHAIL...<.75IN$JPC Link to comment Share on other sites More sharing options...
Powerball Posted July 25, 2015 Share Posted July 25, 2015 For once, we have a cold front coming through at an ideal time of day with an opportunity for a fair amount of sunshine But of course just about all of the other parameters for convection aren't very impressive. It would be nice to get something though. Link to comment Share on other sites More sharing options...
Hoosier Posted July 25, 2015 Share Posted July 25, 2015 Sort of a low confidence scenario but could see storms develop almost overhead later, possibly along lake breeze. Various models suggesting it. Link to comment Share on other sites More sharing options...
IWXwx Posted July 25, 2015 Share Posted July 25, 2015 Sort of a low confidence scenario but could see storms develop almost overhead later, possibly along lake breeze. Various models suggesting it. I wasn't too excited about anything today, but the HRRR, RAP, and 4kNAM all showing storms firing along the breeze/front and drifting southeast. I might see some action before they fall apart after all. Link to comment Share on other sites More sharing options...
Indystorm Posted July 25, 2015 Share Posted July 25, 2015 Storms starting to fire on the Lake Michigan lake breeze or whatever boundary may extend west to the Quad Cities region. At least there might be something to watch this evening even if they don't become svr. Models were correct. Link to comment Share on other sites More sharing options...
Hoosier Posted July 25, 2015 Share Posted July 25, 2015 Storms starting to fire on the Lake Michigan lake breeze or whatever boundary may extend west to the Quad Cities region. At least there might be something to watch this evening even if they don't become svr. Models were correct. Yeah, fired just south of me. Boundary very well defined on KLOT. Link to comment Share on other sites More sharing options...
Powerball Posted July 25, 2015 Share Posted July 25, 2015 And of course today, as marginal as it was, ended up being another failure. Link to comment Share on other sites More sharing options...
Chargers09 Posted July 26, 2015 Share Posted July 26, 2015 And of course today, as marginal as it was, ended up being another failure.Spoke way too soon Link to comment Share on other sites More sharing options...
IWXwx Posted July 26, 2015 Share Posted July 26, 2015 And of course today, as marginal as it was, ended up being another failure. Storm Fail fail. Link to comment Share on other sites More sharing options...
stormtrackertf Posted July 26, 2015 Share Posted July 26, 2015 Looks like my backyard got a decent soaking today. Radar estimates 0.7". Can't check my rain gauge from here, but that would be nice if it actually has some ground truth. Link to comment Share on other sites More sharing options...
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