andyhb Posted October 24, 2012 Share Posted October 24, 2012 DAY 1 CONVECTIVE OUTLOOKNWS STORM PREDICTION CENTER NORMAN OK 1255 AM CDT WED OCT 24 2012 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM WRN UPPER MI AND ADJACENT WRN LK SUPERIOR SSWWD INTO IA/ERN NEB... ...SYNOPSIS... THE LARGE SCALE MID- AND UPPER-LEVEL TROUGH OVER THE WRN U.S. IS FORECAST TO MAKE STEADY EWD PROGRESS THIS PERIOD...AS EMBEDDED SHORTER-WAVELENGTH TROUGHING SHIFTS QUICKLY EWD FROM THE GREAT BASIN/INTERIOR W EARLY TO THE PLAINS BY THE END OF THE PERIOD. THE LARGE-SCALE TROUGH WILL BE ACCOMPANIED BY VERY STRONG FLOW ALOFT...WHICH WILL SPREAD INTO THE CENTRAL U.S. THROUGH THE PERIOD. AT THE SURFACE...A LOW INITIALLY INVOF KS/NEB IS FORECAST TO SHIFT NEWD TOWARD SERN MN THROUGH THE FIRST HALF OF THE PERIOD...WHILE PRIMARY CYCLOGENESIS INCREASES ACROSS THE SERN CO VICINITY. AS THIS OCCURS...THE SURFACE FRONT SHOULD MAKE LITTLE EWD PROGRESS ACROSS THE PLAINS. DURING THE SECOND HALF OF THE PERIOD HOWEVER...THE CO LOW IS PROGGED TO SHIFT QUICKLY NEWD AND EVENTUALLY MERGE WITH THE MN LOW. BY THE END OF THE PERIOD...THE LOW SHOULD RESIDE INVOF WI...WITH THE TRAILING COLD FRONT HAVING SHIFTED EWD TO EXTEND FROM WI SSWWD ACROSS CENTRAL OK INTO NRN AND WRN TX BY 25/12Z. ...LK SUPERIOR/WRN UPPER MI SSWWD INTO THE MID MO VALLEY AREA... AS THE AFOREMENTIONED COLD FRONT LINGERS IN PLACE ACROSS THE CENTRAL U.S. AHEAD OF THE WRN UPPER TROUGH DURING THE FIRST HALF OF THE PERIOD...A CAPPED BOUNDARY LAYER WILL PREVAIL AS THE UPPER RIDGE AND ASSOCIATED SUBSIDENCE PERSIST. WITH DAYTIME HEATING OF THE MOIST WARM SECTOR...MODERATE CAPE IS FORECAST TO DEVELOP ABOVE THE BOUNDARY-LAYER CAP. EVENTUALLY...AS HEIGHT FALLS SPREAD ACROSS THE PLAINS...SOME CAP WEAKENING IS FORECAST -- WHICH MAY BE SUFFICIENT TO ALLOW SOME REALIZATION OF THE UNSTABLE ENVIRONMENT IN THE FORM OF ISOLATED STORM DEVELOPMENT. INITIATION APPEARS MOST LIKELY TO OCCUR OVER THE UPPER MS VALLEY IN THE 22-00Z TIME FRAME...ALONG THE IMMEDIATE FRONTAL ZONE. SHOULD THIS INDEED OCCUR...LARGE HAIL AND DAMAGING WINDS WILL BE POSSIBLE...AS STORMS QUICKLY ORGANIZE GIVEN VERY FAVORABLE BACKGROUND FLOW FIELD. A TORNADO OR TWO WOULD ALSO BE POSSIBLE -- PARTICULARLY INVOF WRN WI -- TO THE NE OF THE ANTICIPATED SURFACE LOW POSITION WHERE LOW-LEVEL SHEAR WOULD BE MAXIMIZED. ATTM...WILL MAINTAIN ONLY 15% HAIL/WIND AND 5% TORNADO PROBABILITY...AS EVOLUTION OF AFTERNOON SURFACE-BASED STORMS ALONG THE FRONT IS NOT A CERTAINTY. SEVERAL HIGH-RES MODELS -- ALONG WITH A BROAD VIEW OF THE OVERALL PATTERN -- SUGGEST THAT CAPPING COULD HINDER SUCH DEVELOPMENT...WITH CONVECTIVE DEVELOPMENT BEING MAINLY CONFINED TO THE COOL SIDE OF THE BOUNDARY AFTER DARK. STILL...WITH HAIL LIKELY TO OCCUR EVEN IN THIS SCENARIO...SLIGHT RISK IS WELL WARRANTED...BUT AN INCREASE IN PROBABILITIES WILL NOT BE INSERTED THIS FORECAST DUE TO THE UNCERTAINTIES. WHETHER DIURNAL/SURFACE-BASED STORMS DEVELOP OR NOT...AN EXPANSION IN CONVECTION ON THE COOL SIDE OF THE BOUNDARY APPEARS FAIRLY LIKELY DURING THE EVENING AND OVERNIGHT...WITH SHOWERS AND STORMS DEVELOPING SWD ACROSS KS -- AND POSSIBLY INTO NRN OK/WRN MO -- THROUGH THE END OF THE PERIOD. WHILE SOME HAIL THREAT IS POSSIBLE...STORMS SHOULD WANE IN INTENSITY THROUGH LATTER STAGES OF THE PERIOD. ..GOSS/GARNER.. 10/24/2012 Link to comment Share on other sites More sharing options...
MnWeatherman Posted October 24, 2012 Share Posted October 24, 2012 SPC seems to be downplaying it right now, will be interesting to how it progresses tomorrow. Also mentioning daytime initiation. Link to comment Share on other sites More sharing options...
andyhb Posted October 24, 2012 Share Posted October 24, 2012 SPC seems to be downplaying it right now, will be interesting to how it progresses tomorrow. Also mentioning daytime initiation. They are downplaying it for good reason, the question of whether initiation takes place within the primed area is significant. Link to comment Share on other sites More sharing options...
ZackH Posted October 24, 2012 Share Posted October 24, 2012 I completely agree with a 5%,15,15 right now. Link to comment Share on other sites More sharing options...
Buckeye05 Posted October 24, 2012 Share Posted October 24, 2012 Clouds and drizzle overspreading IA/MN/WI. Yawn. Link to comment Share on other sites More sharing options...
ZackH Posted October 24, 2012 Share Posted October 24, 2012 I wouldn't sleep on this system yet. The clear pockets in Iowa are poking through nicely. There is also a nice boundary moving through north central/central IA right now with some agitated Cu... I think stuff will eventually pop but it may be further south than initially thought and it may be close to or after dark. NE Iowa is looking primed if something can break through. All mesoscale models seem to be showing an elevated mess, however. Latest discussion says that modified soundings show that its going to be hard to break the cap with the boundary feature I was talking about. Link to comment Share on other sites More sharing options...
Siberian Express Posted October 24, 2012 Share Posted October 24, 2012 Due to worries about cloud cover, capping, and instability, we are sitting tomorrow out after all. If you look at the RAP when comparing the NAM... the instability is nowhere close (near the best shear profiles). The RAP looks like cloud cover all day long. On top of that, the NAM generally over-estimated today's temps in the main target area by 5+ degrees. I strongly believe, that if anything gets going, it will be after dark and its too risky for a 6-7 hour drive there and back. Also, the 00z NAM shows stronger capping from what I'm seeing except for right on and above the warm front. If nothing goes up early, it will be shame to see such a waste of wonderful shear parameters. Good call....foggy drizzle and 60 in SE MN at this time. Link to comment Share on other sites More sharing options...
MnWeatherman Posted October 24, 2012 Share Posted October 24, 2012 HRRR seems to be handling today quite well. I don't think it will amount to much as once thought. Link to comment Share on other sites More sharing options...
ZackH Posted October 24, 2012 Share Posted October 24, 2012 HRRR seems to be handling today quite well. I don't think it will amount to much as once thought. Quite honestly it was never thought to amount to much if the cap couldn't break which was always thought to be a more than average possibility. The slight risk was also the very low end. If there hadn't been such a strong cap and there were breaks in the clouds, it had a lot of potential, but these conditions weren't met and the good possibility of these conditions were well known more than a day before the event. Link to comment Share on other sites More sharing options...
prinsburg_wx Posted October 25, 2012 Share Posted October 25, 2012 First accumulating snow of the season for parts of w MN possible. SPECIAL WEATHER STATEMENTNATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 931 PM CDT WED OCT 24 2012 MNZ041>045-047>051-054>059-064>067-073>075-082-091-250930- DOUGLAS-TODD-MORRISON-MILLE LACS-KANABEC-STEVENS-POPE-STEARNS- BENTON-SHERBURNE-LAC QUI PARLE-SWIFT-CHIPPEWA-KANDIYOHI-MEEKER- WRIGHT-YELLOW MEDICINE-RENVILLE-MCLEOD-SIBLEY-REDWOOD-BROWN- NICOLLET-WATONWAN-MARTIN- INCLUDING THE CITIES OF...ALEXANDRIA...LONG PRAIRIE... LITTLE FALLS...PRINCETON...MORA...MORRIS...GLENWOOD...ST. CLOUD... FOLEY...ELK RIVER...MADISON...BENSON...MONTEVIDEO...WILLMAR... LITCHFIELD...MONTICELLO...GRANITE FALLS...OLIVIA...HUTCHINSON... GAYLORD...REDWOOD FALLS...NEW ULM...ST. PETER...ST. JAMES... FAIRMONT 931 PM CDT WED OCT 24 2012 ...ACCUMULATING SNOW EXPECTED LATE TONIGHT AND THURSDAY MORNING... AN UPPER LEVEL SYSTEM WILL SWING NORTHEAST FROM THE CENTRAL PLAINS TO THE UPPER MISSISSIPPI VALLEY LATE TONIGHT. AS A RESULT...WIDESPREAD PRECIPITATION WILL DEVELOP OVERNIGHT. AS COLDER AIR IS INGESTED INTO THE SYSTEM LATE TONIGHT...THE RAIN WILL CHANGE TO SNOW FROM WEST TO EAST. RAIN MAY MIX WITH OR CHANGE TO SNOW OVER FAR WESTERN MINNESOTA AS EARLY AS 1 TO 4 AM...REDWOOD FALLS AND SAINT CLOUD BETWEEN 4 AM AND 7 AM...AND FAIRMONT...MANKATO...AND CAMBRIDGE JUST AFTER 7 AM. AT THIS POINT...THE BEST CHANCE FOR ACCUMULATING SNOW IS ALONG AN AXIS ROUGHLY FROM REDWOOD FALLS TO JUST WEST OF SAINT CLOUD. ACCUMULATIONS OF 1 TO POSSIBLY 3 INCHES ARE EXPECTED. DUE TO THE WARM GROUND TEMPERATURES AND WET CONDITIONS LEFT BEHIND BY EARLIER RAIN...IT MAY TAKE SOME TIME FOR THE SNOW TO BEGIN STICKING. ACCUMULATIONS WILL ALSO DEPEND ON HOW COLD THE AIR TEMPERATURE CAN GET. IF THEY DO DROP BELOW FREEZING...ACCUMULATIONS ON ELEVATED AND GRASSY SURFACES CAN BE EXPECTED. BRIDGES AND OVERPASSES WILL ALSO BE PRONE TO SLICK CONDITIONS. IF TEMPERATURES REMAIN JUST ABOVE FREEZING...IT WILL BE VERY DIFFICULT TO FIND ACCUMULATING SNOW. THIS WILL BE THE FIRST CHANCE FOR ACCUMULATING SNOW ACROSS MUCH OF THE AREA THIS SEASON. AFTER A RELATIVELY SNOWLESS WINTER LAST YEAR...DRIVERS ARE URGED TO TAKE IT EASY FOR THE THURSDAY MORNING COMMUTE AND WATCH FOR SLICK SPOTS. Link to comment Share on other sites More sharing options...
cyclone77 Posted October 25, 2012 Share Posted October 25, 2012 Probably a bit overdone, but it sure looks like a narrow stripe of decent accumulations for MN. Surprised there's no advisories given it's the first snowfall of the season for most areas. The way the radar looks right now I think some folks in MN could be in for a bit of a surprise by tomorrow... Link to comment Share on other sites More sharing options...
mnweather Posted October 28, 2012 Share Posted October 28, 2012 WWA issued for portions of western MN and eastern ND. 2-5" expected. Link to comment Share on other sites More sharing options...
prinsburg_wx Posted November 22, 2012 Share Posted November 22, 2012 Happy Thanksgiving Everyone. Link to comment Share on other sites More sharing options...
ksstormhunter Posted November 26, 2012 Share Posted November 26, 2012 Smartcast for E TX- LA 26/16Z-27/16Z Currently tracking area from Ruston Regional, LA to Nacogdoches, TX, and Barksdale AFB, LA with the highest threat of convection potential. Seeing potential for hail between 1-3” and convective gusts up to 58MPH Possible today. Nacogdoches, TX: Looking for Thunderstorms on station around 03Z through 08Z, with potential hail of around 1 to 1.8”, Convective wind gusts of 53MPH possible. Potential for severe weather during this time frame is about 48% chance. After 09Z, looking at a few hours of steady light rain Ruston, TX: Looking for Thunderstorms on station around 04Z to 08Z, with potential hail of around 1.2 to 2.6”, with convective gusts around 53MPH possible. Currently there is around a 40% chance of seeing severe weather criteria in this region. Full output uploaded http://smartwxmodel.net/update.htm Any thoughts on today's severe weather threat across the TX and LA areas for today... Link to comment Share on other sites More sharing options...
ksstormhunter Posted November 27, 2012 Share Posted November 27, 2012 SmartCast Update 26/23Z to 27/23Z Tracking Victoria to Lufkin to Nacogdoches and Huntsville with the highest threat of severe weather. Around 55 to 58% chance of seeing some severe weather criteria over the next 4-8 hours. Potential to see hail up to 2.3” and wind gusts up to 74MPH possible across this area. Lufkin Area: Looking for TSTMS from 04Z to 08Z, Hail up to 1.8” possible and winds up to 69MPH possible. Nacogdoches Area: Looking for TSTMS from 01Z through 07Z, Hail up to 1.6” possible with winds up to 55MPH possible. Huntsville, TX Area: Looking for TSTMS from 04Z to 07Z, Hail up to 1.6” possible, with winds up to 68MPH. Link to comment Share on other sites More sharing options...
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