SmokeEater Posted July 26, 2011 Share Posted July 26, 2011 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1136 AM CDT TUE JUL 26 2011 VALID 261630Z - 271200Z ...THERE IS A MDT RISK OF SVR TSTMS OVER NORTH CENTRAL/NERN SD AND SOUTH CENTRAL/SERN ND... ...THERE IS A SLGT RISK OF SVR TSTMS OVER THE NRN/CENTRAL PLAINS INTO THE UPPER MS VALLEY... ..THERE IS A SLGT RISK OF SVR TSTMS OVER THE NERN STATES ..NRN/CENTRAL PLAINS UPPER VORTICITY MAX OVER SRN ALBERTA IS FORECAST TO MOVE EWD ACROSS THE SRN PRAIRIE PROVINCES WITH GRADUAL HEIGHT FALLS OVERSPREADING THE NRN PLAINS THROUGH TONIGHT. ASSOCIATED COLD FRONT FROM ERN MT SWWD ACROSS WY WILL MOVE EWD ACROSS PART SOD THE NRN PLAINS...REACHING A LINE FROM EXTREME ERN ND/CENTRAL SD/CENTRAL WY BY THE END OF THE PERIOD. A WARM FRONT FROM SERN SD INTO A LOW OVER SERN MT WILL LIFT NWD TODAY...ALTHOUGH ITS PROGRESS MAY BE LIMITED BY CLOUD COVER SPREADING ENEWD OVER THE NRN TWO-THIRDS OF SD. VERY STEEP MID LEVEL LAPSE RATES AND ATTENDANT EML HAVE OVERSPREAD THE REGION...INDICATING THAT SURFACE-BASED STORMS WILL BE DELAYED UNTIL LATER THIS AFTERNOON AND EVENING. CURRENT WIDELY SCATTERED ELEVATED STORMS FROM NWRN ND SEWD INTO NERN SD ARE ASSOCIATED WITH WARM ADVECTION IN THE 850-700 MB LAYER...AND ARE EXPECTED TO SLOWLY SPREAD EWD. STRONGER CELLS MAY PRODUCE ISOLATED HAIL...SEE SWOMCD 1746 FOR MORE NEAR-TERM DETAILS. AS LOW LEVEL MOISTURE CONTINUES TO SPREAD NWD THIS AFTERNOON AND HEATING OCCURS WITHIN BREAKS IN CLOUD COVER...ATMOSPHERE WILL BECOME INCREASINGLY UNSTABLE FROM SERN SD INTO CENTRAL/SERN ND...WITH MLCAPE OF 2000-3000 J/KG EXPECTED. THE CAP IS EXPECTED TO GRADUALLY WEAKEN WITH NEW STORMS INITIATING OVER PARTS OF WRN ND INTO CENTRAL SD BY MID-LATE AFTERNOON. VERTICAL WIND PROFILES ARE FORECAST TO EXHIBIT STRONG VEERING AND SPEED INCREASE IN THE LOWEST 3-4 KM...WHICH WILL PROMOTE SUPERCELL DEVELOPMENT. IF DISCRETE STORMS CAN BE MAINTAINED AFTER INITIATION...THERE WILL BE POTENTIAL FOR STRONGER CELLS TO PRODUCE VERY LARGE HAIL AND A FEW TORNADOES...SEVERAL OF WHICH COULD BE STRONG. STORMS ARE EXPECTED TO MOVE EWD THROUGH THE EVENING HOURS...WITH THE POSSIBILITY OF SOME UPSCALE GROWTH INTO ONE OR TWO MCS/S MOVING TOWARD THE UPPER MS VALLEY. OTHER STORMS ARE EXPECTED TO DEVELOP SSWWD ALONG THE SURFACE TROUGH EXTENDING OVER WRN/CENTRAL NEB AND NERN CO. STRONG DIABATIC HEATING AND STEEP LAPSE RATES COUPLED WITH SUFFICIENT VERTICAL SHEAR WILL BE FAVORABLE FOR SEVERE STORMS INCLUDING A FEW SUPERCELLS. LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY THREATS. STORMS WILL SPREAD ENEWD THROUGH THE EVENING HOURS BEFORE DIMINISHING AFTER 03-06Z, Link to comment Share on other sites More sharing options...
L.B. LaForce Posted July 26, 2011 Share Posted July 26, 2011 I sure hope this stuff near ABR doesn't mess up today Link to comment Share on other sites More sharing options...
cmichweather Posted July 26, 2011 Share Posted July 26, 2011 Looking at Gwinner for the time being, but will probably head a bit west from there. Nice ya I think we are gonna end up targeting Ellendale, ND. Maybe i'll see you out there. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted July 26, 2011 Share Posted July 26, 2011 Baro, que me in on what a DMC is? I've been trying to figure out what it is, but just cant think of it I presume this post is made in jest, since I've always thought it meant Deep Moist Convection. Correct sir. Link to comment Share on other sites More sharing options...
tornadotony Posted July 26, 2011 Share Posted July 26, 2011 I sure hope this stuff near ABR doesn't mess up today I would highly doubt it. It's shallow, lacking major cirrus, and really on the eastern edge of the initation zone. The initiation zone has that pre-outbreak look to it, with streaks of Cu and AcCas. Link to comment Share on other sites More sharing options...
Ian Posted July 26, 2011 Share Posted July 26, 2011 dakotas have been hot lately Link to comment Share on other sites More sharing options...
L.B. LaForce Posted July 26, 2011 Share Posted July 26, 2011 I'm 2 miles east of Ellendale heading into town to get some quick lunch, then prolly head south. Cmich, you there yet? Link to comment Share on other sites More sharing options...
Derek30 Posted July 26, 2011 Share Posted July 26, 2011 I'm concerned that the low level jet will break off and remain in North Dakota and Minnesota tonight. If things go well enough, southern Manitoba could see some strong elevated activity tonight. Link to comment Share on other sites More sharing options...
Chicago Storm Posted July 26, 2011 Share Posted July 26, 2011 The RUC is showing great potential for portions of SD... Link to comment Share on other sites More sharing options...
L.B. LaForce Posted July 26, 2011 Share Posted July 26, 2011 Looks like the main band on the SW side if KABR radar is the WF pushing northeastward. Link to comment Share on other sites More sharing options...
ICEHOCEY77 Posted July 26, 2011 Share Posted July 26, 2011 new meso disc. NEW TSTM DEVELOPMENT IS ANTICIPATED ACROSS PORTIONS OF CNTRL/NERN SD AND INTO ND WITHIN THE NEXT COUPLE OF HOURS. INSTABILITY FORCING AND SHEAR ACROSS THESE AREAS WILL LIKELY SUPPORT THE ISSUANCE OF A WATCH. VERY WARM MID LEVEL TEMPERATURES /14-16C AT 700MB/ ARE LIKELY INHIBITING THE INITIATION OF SURFACE-BASED STORMS AMIDST SURFACE LOW AND STRONGLY UNSTABLE WARM SECTOR OVER SD ATTM. WIND SHIFT AND WEAK EFFECTIVE COLD FRONT DUE TO PERSISTENT CLOUD COVER...AND A DRYLINE...ARE SPREADING GRADUALLY EAST AS AN ANTICYCLONICALLY CURVED MID-LEVEL JET STREAK OF ABOUT 40-50KT WAS CRESTING THE AREA FROM ERN WY TO SERN ND. AS STRONGER SHORT WAVE TROUGH DEVELOPS EAST FROM MT/WY AND SURFACE HEATING CONTINUES...EXPECT THAT CONTINUED FORCING NEAR THE LOW AND WARM FRONT WILL EVENTUALLY BE SUFFICIENT TO BREACH CAPPING ACROSS THE AREA AND RESULT IN TSTM DEVELOPMENT. AS THIS OCCURS IN THE 22-00 UTC TIME FRAME...PARAMETERS WILL BE MORE THAN ADEQUATE FOR SUPERCELL STORMS WITH ATTENDANT THREATS OF VERY LARGE HAIL AND HIGH WINDS. A TORNADO THREAT MAY ALSO EVOLVE...ESPECIALLY FOR CELLS NEAR THE LOW AND WARM FRONT WHERE LOW LEVEL MOISTURE AND SHEAR WILL BE MORE SUPPORTIVE OF STRONG LOW-LEVEL UPDRAFT ROTATION. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted July 26, 2011 Share Posted July 26, 2011 Thunderstorm development along the cold front in western NE, definitely not the big game in town, but a MCD/WW is probably coming soon here. Link to comment Share on other sites More sharing options...
Chicago Storm Posted July 26, 2011 Share Posted July 26, 2011 The first attempt at initiation looks to be taking place in western Sully Co, SD. Other pockets of agitated/towering CU in the area. Link to comment Share on other sites More sharing options...
wisconsinwx Posted July 26, 2011 Share Posted July 26, 2011 It'd be nice if TWC was actually doing their job, ie. preparing residents in the Dakotas for a potential outbreak rather than showing a photographer doing his thing. I feel like every hour I turn it on during a weekday evening they have longform (I know this has been going on for several years). Link to comment Share on other sites More sharing options...
andyhb Posted July 26, 2011 Share Posted July 26, 2011 This threat somewhat reminds me of the June 20th threat, except the storms will be moving more northeast rather than almost due north. Link to comment Share on other sites More sharing options...
Jim Martin Posted July 26, 2011 Share Posted July 26, 2011 Storms starting to fire in eastern Dewey county, and Sully county SD as well, near Onida. Link to comment Share on other sites More sharing options...
SmokeEater Posted July 26, 2011 Share Posted July 26, 2011 Tops already to almost 60,000 with this storm. BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE ABERDEEN SD 528 PM CDT TUE JUL 26 2011 THE NATIONAL WEATHER SERVICE IN ABERDEEN HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... SOUTHWESTERN POTTER COUNTY IN NORTH CENTRAL SOUTH DAKOTA... NORTHERN SULLY COUNTY IN CENTRAL SOUTH DAKOTA... * UNTIL 615 PM CDT * AT 525 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED 5 MILES SOUTHEAST OF SUTTON BAY REC AREA...OR 13 MILES NORTHWEST OF ONIDA...MOVING NORTHEAST AT 30 MPH. * THE SEVERE THUNDERSTORM WILL BE NEAR... AGAR AROUND 540 PM CDT... GORMAN AROUND 550 PM CDT... GETTYSBURG AROUND 605 PM CDT... THIS WARNING INCLUDES HIGHWAY 83 BETWEEN MILE MARKERS 156 AND 180. THIS WARNING INCLUDES HIGHWAY 212 BETWEEN MILE MARKERS 215 AND 227. Link to comment Share on other sites More sharing options...
SmokeEater Posted July 26, 2011 Share Posted July 26, 2011 URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 689 NWS STORM PREDICTION CENTER NORMAN OK 525 PM CDT TUE JUL 26 2011 THE NWS STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS OF SOUTH-CENTRAL NORTH DAKOTA CENTRAL SOUTH DAKOTA EFFECTIVE THIS TUESDAY AFTERNOON AND WEDNESDAY MORNING FROM 525 PM UNTIL 100 AM CDT. SEVERAL TORNADOES WIDELY SCATTERED DAMAGING WINDS ISOLATED WIND GUSTS TO 70 MPH POSSIBLE SCATTERED LARGE HAIL ISOLATED HAIL TO 2.5 INCHES IN DIAMETER POSSIBLE THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES WEST OF CHAMBERLAIN SOUTH DAKOTA TO 85 MILES NORTH NORTHEAST OF MOBRIDGE SOUTH DAKOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9). REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. OTHER WATCH INFORMATION...CONTINUE...WW 686...WW 687...WW 688... DISCUSSION...INCIPIENT SURFACE-BASED TSTM DEVELOPMENT IS UNDERWAY FROM PIR-MBG...N OF SURFACE LOW AND ATTENDANT WARM FRONT. MODIFICATION OF 20Z ABR SOUNDING FOR CURRENT SURFACE CONDITIONS NEAR WARM FRONT SUGGESTS THAT CAP HAS BECOME QUITE WEAK WITH MLCAPE VALUES AROUND 2000-3000 J/KG. MOREOVER...STRENGTHENING MIDLEVEL WIND FIELD ASSOCIATED WITH DE-AMPLIFYING SHORT WAVE TROUGH OVER THE NRN HIGH PLAINS COUPLED WITH BACKED LOW-LEVEL FLOW N OF WARM FRONT IS RESULTING IN A RATHER STRONGLY SHEARED ENVIRONMENT. AS SUCH...SETUP APPEARS FAVORABLE FOR SUPERCELL EVOLUTION WITH A RISK FOR TORNADOES...LARGE HAIL AND LOCALLY DAMAGING WINDS. AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600. MEAN STORM MOTION VECTOR 25020. ...MEAD Link to comment Share on other sites More sharing options...
David Reimer Posted July 26, 2011 Share Posted July 26, 2011 So begins what looks to be an epic night. EDIT: This post is a fail. Link to comment Share on other sites More sharing options...
Radtechwxman Posted July 26, 2011 Share Posted July 26, 2011 so is anyone else curious why there is a 10 hatched tornadoes yet the watch is low for strong tornadoes? just checked out the parameters. Northeast to Central SD and along the SD/ND border looks quite prime for strong tornadoes if storms stay discrete. sfc-1km helicity is 200-350. 0-1km ehi is an 8 in part of the watch. 0-1km shear is 20-30knts. and sig tor parameter for fixed layer is a 5. and 3 for effective layer. parameters arent off the charts but def are plenty adequete for strong tornadoes with these values. very interesting. sfc winds are also backed nicely in vicinity of pressure falls. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted July 26, 2011 Share Posted July 26, 2011 SPC went with a severe watch box for western NE. I would probably be called in for severe ops but I just worked the 4 AM -1 PM shift. Ok, back to SD... Link to comment Share on other sites More sharing options...
Thundersnow12 Posted July 26, 2011 Share Posted July 26, 2011 The storm to watch right now is the one southwest of Gettsburg, SD and already has a nice TBSS on it and will continue to move into highly sheared environment L.B. is in front of it heading south. Link to comment Share on other sites More sharing options...
L.B. LaForce Posted July 26, 2011 Share Posted July 26, 2011 WTF, lining out already!? Link to comment Share on other sites More sharing options...
tornadotony Posted July 26, 2011 Share Posted July 26, 2011 Real threat may be in SW MN, with that storm in Lyon and Yellow Medicine Counties. Link to comment Share on other sites More sharing options...
Chicago Storm Posted July 26, 2011 Share Posted July 26, 2011 WTF, lining out already!? 12z 4km SPC WRF showed it would quickly become linear...though it kept a few stronger cores within the line. Link to comment Share on other sites More sharing options...
Jim Martin Posted July 26, 2011 Share Posted July 26, 2011 Storm in Lyon County MN already over 40,000 ft high. Link to comment Share on other sites More sharing options...
andyhb Posted July 26, 2011 Share Posted July 26, 2011 Looks like two cells are becoming more discrete. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted July 26, 2011 Share Posted July 26, 2011 It's not severe warned yet but the storm east of Pontiac, IL has echoes to 52kft. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted July 26, 2011 Share Posted July 26, 2011 supercell near Hoven, SD now tor warned with rotation increasing. Link to comment Share on other sites More sharing options...
andyhb Posted July 26, 2011 Share Posted July 26, 2011 BULLETIN -EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE ABERDEEN SD 703 PM CDT TUE JUL 26 2011 THE NATIONAL WEATHER SERVICE IN ABERDEEN HAS ISSUED A TORNADO WARNING FOR... SOUTHWESTERN EDMUNDS COUNTY IN NORTH CENTRAL SOUTH DAKOTA... NORTHEASTERN POTTER COUNTY IN NORTH CENTRAL SOUTH DAKOTA... SOUTHEASTERN WALWORTH COUNTY IN NORTH CENTRAL SOUTH DAKOTA... UNTIL 730 PM CDT AT 658 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A FUNNEL CLOUD NEAR HOVEN...OR 17 MILES SOUTHEAST OF SELBY. A TORNADO MAY DEVELOP AT ANY TIME! DOPPLER RADAR SHOWED THIS TORNADIC STORM MOVING EAST AT 25 MPH. THE TORNADO WILL BE NEAR... TOLSTOY AROUND 725 PM CDT... Link to comment Share on other sites More sharing options...
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