ShawnEastTN Posted February 14, 2015 Share Posted February 14, 2015 Dare I say we aren't even talking about the second potential event that is now just under 7 days out Fri/Sat of next week. Link to comment Share on other sites More sharing options...
Windspeed Posted February 14, 2015 Author Share Posted February 14, 2015 From David Aldrich at WVLT: Based on 7 AM (12z) runs today...ECMWF model8 to 13 inches of snow (some sleet mix suggested here, which would significantly reduce snowfall amounts)North American Mesoscale (NAM) model1 to 2 inches of snow on Monday5 to 7 inches of snow on Tuesday_______6 to 9 inches of snow NAM Total for Monday and TuesdayGlobal Forecast System (GFS) model3 to 6 inches of snow on Monday0.5 to 1.0 inches of snow spread out over three days, namely Tuesday, Wednesday and Thursday______3.5 to 7 inches of snow GFS Total for the weekCANADIAN model4 to 8 inches of snow for MondayStay tuned. All of this WILL change again tomorrow. Surprise, surprise. Need today’s cold front to move in FIRST, in my opinion, before these hyper models settle down...or crank it up. Be sure to watch Meteorologist John Carroll tonight at 6 PM and 11 PM. I'll be in the Weather Center with John on Sunday. Link to comment Share on other sites More sharing options...
Blue Ridge Posted February 14, 2015 Share Posted February 14, 2015 MRX PM AFD is up. Would copy/paste, but am on mobile. Watches are going up. Based on what I skimmed, a general 3-6 w/ 6-10 higher elevations is expected. Link to comment Share on other sites More sharing options...
ShawnEastTN Posted February 14, 2015 Share Posted February 14, 2015 MRX .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)......SIGNIFICANT WINTER STORM POSSIBLE FOR THE TENNESSEE VALLEY ANDSOUTHERN APPALACHIAN REGION LATE SUNDAY NIGHT THROUGH MONDAYNIGHT...CONFIDENCE IS INCREASING THAT A SIGNIFICANT WINTER STORM WITHWIDESPREAD HEAVY SNOWFALL WILL IMPACT THE REGION EARLY THIS UPCOMINGWEEK. THE COMBINATION OF COLD...SUBFREEZING AIR AT THE SURFACECOMBINED WITH POTENTIALLY SOME GOOD MOISTURE AND LIFT FROM A 700 MBJET WILL HELP TO GENERATE WIDESPREAD AND POTENTIALLY LOCALLY HEAVYPRECIPITATION. ALL MODELS SOLUTIONS...WITH SOME MINOR TIMINGDIFFERENCES SHOW THIS SITUATION...THE NAM BEING SLIGHTLY DRIER ONTHE INITIAL ROUND OF QPF MONDAY. HOWEVER...THE GFS ENSEMBLES INPARTICULAR HAVE COME MUCH MORE IN LINE WITH THE ECMWF AND CANADIANSOLUTIONS OF SHOWING SNOW /WITH SOME FAIRLY HIGH QPF AMOUNTS/ MOVINGINTO THE REGION FROM WEST TO EAST EARLY MONDAY MORNING...ANDOVERSPREADING THE FORECAST AREA THROUGHOUT THE DAY.THIS SNOWFALL WILL INCREASE IN INTENSITY AS IT OVERSPREADS THEREGION...WITH MODELS SHOWING THE CENTRAL AND SOUTHERN VALLEYS ANDSOUTHERN PLATEAU RECEIVING SLIGHTLY HIGHER AMOUNTS...ALONG WITH THEEAST TENNESSEE AND NORTH CAROLINA MOUNTAINS. STILL...WIDESPREADMEANINGFUL SNOWFALL ACCUMULATIONS ARE EXPECTED EVERYWHERE...WITH 3TO 6 INCHES /WITH LOCALLY HIGHER AMOUNTS/ THROUGHOUT THEVALLEY...AND 6-10 INCHES /WITH LOCALLY HIGHER AMOUNTS IN THEMOUNTAINS/. GIVEN THE COLD...SUBFREEZING AIR THAT WILL HAVE BEEN INPLACE FOR 24-36 HOURS...ANY SNOW THAT FALLS WILL QUICKLY ACCUMULATE.THE COLD AIR IN PLACE ALOFT WILL RESULT IN A DRIER SNOW...WITHRATIOS OF 13:1 OR 14:1 BEING COMMON. THIS FACTOR COULD LEAD TO EVENHIGHER AMOUNTS IN LOCALIZED AREAS WHERE MESOSCALE BANDING SETS UP.SNOW WILL BEGIN TO TAPER OFF DURING THE EVENING...BUT LOCATIONSACROSS FAR SOUTHEAST TENNESSEE AND SOUTHWEST NORTH CAROLINA COULDSEE AN EXTENDED PERIOD OF SNOW INTO THE EVENING AND NIGHT...BEFORETHINGS TAPER OFF. WITH THE COLD TEMPERATURES IN PLACE...ANY SNOWTHAT FALLS COULD LINGER ON THE GROUND FOR SEVERAL DAYS....RESULTINGIN HUGE SOCIETAL IMPACT POTENTIALLY. GIVEN THE INCREASED CONFIDENCEAND ALL OF THIS...HAVE ISSUED A WINTER STORM WATCH FOR THE ENTIREFORECAST AREA FROM 06Z MONDAY THRU 12Z TUESDAY.THEREAFTER...THE FORECAST BECOMES A BIT MORE COMPLICATED. ASMENTIONED THE GFS...CANADIAN AND ECMWF SOLUTIONS FAVOR A SOMEWHATDRIER AND COOLER PERIOD ON TUESDAY. THE 12Z NAM ON THE OTHER HANDWANTS TO ADVECT WARMER AIR ALOFT AND A LOT MORE MOISTURE INTO THEREGION ON TUESDAY...GIVING ANOTHER ROUND OF ACCUMULATING SNOWFALLAND SOME SLEET/ICE TO THE SOUTHERN VALLEY. GIVEN THAT THE NAM IS THEOUTLIER...HAVE MAINTAINED AN ALL SNOW FORECAST FOR MOST OF TUESDAYFOR NOW...BUT WILL CONTINUE TO MONITOR. OVERALL...THINK THATACCUMULATIONS WILL FAVOR THE MOUNTAINS AND DEFINITELY BE MUCHLIGHTER THAN MONDAY. BUT SOME LOCATIONS COULD PICK UP AN ADDITIONALINCH OR SO IF MOISTURE/PRECIPITATION TRENDS FURTHER WEST. MODELSSHOW A STRONG COOL DOWN FOR THE MIDDLE OF THE WEEK AS THINGS CLEAROFF BY WEDNESDAY INTO WEDNESDAY NIGHT. LOWS BY THURSDAY MORNING WILLLIKELY BE IN THE LOWER SINGLE DIGITS...WITH SOME AREAS POTENTIALLYDROPPING BELOW ZERO...A RARITY FOR OUR VALLEY LOCATIONS! THIS WILLONLY HELP TO REINFORCE ANY SNOWPACK IN PLACE...AND KEEP UNTREATEDROADS SLICK AND ICY. ANOTHER STORM SYSTEM IS POSSIBLE LATE NEXTWEEK...BUT FOR NOW...HAVE FOCUSED MOST OF THE DETAIL IN THE NEXT 4TO 5 DAYS. Link to comment Share on other sites More sharing options...
Mr Bob Posted February 14, 2015 Share Posted February 14, 2015 well now I'm getting nervous. Looks like im slowly starting to trend out of the good stuff. Just have to hope things trend slightly cooler for my area I suppose, or just plain end up verifying colder. I am going to be stuck in Chatt all week...It looks okay right now...Sometimes the edge is the best place to be as you can really cash in if you stay all snow. Link to comment Share on other sites More sharing options...
ShawnEastTN Posted February 14, 2015 Share Posted February 14, 2015 I am going to be stuck in Chatt all week...It looks okay right now...Sometimes the edge is the best place to be as you can really cash in if you stay all snow. I concur the edge precip zones have the potential to pile it on. Link to comment Share on other sites More sharing options...
Chattownsnow Posted February 14, 2015 Share Posted February 14, 2015 I am going to be stuck in Chatt all week...It looks okay right now...Sometimes the edge is the best place to be as you can really cash in if you stay all snow. that sometimes is what I'm worried about lol. I have seen it go both ways before. Chattanooga has gotten very lucky in recent years though. I would love to see Nashville get plastered though. They have waited too long. Link to comment Share on other sites More sharing options...
Stovepipe Posted February 14, 2015 Share Posted February 14, 2015 Welp, looks like I'm gonna have to stock up on more beer than I thought. I bet schools are out the entire week around here. Gonna be a goodun. Link to comment Share on other sites More sharing options...
Stovepipe Posted February 14, 2015 Share Posted February 14, 2015 18z NAM: Link to comment Share on other sites More sharing options...
Windspeed Posted February 14, 2015 Author Share Posted February 14, 2015 Welp, looks like I'm gonna have to stock up on more beer than I thought. I bet schools are out the entire week around here. Gonna be a goodun. You might want to get some bourbon looking at these temperature maps. Link to comment Share on other sites More sharing options...
Stovepipe Posted February 14, 2015 Share Posted February 14, 2015 You might want to get some bourbon looking at these temperature maps. Got my bourbon last night, I'm good to go on that! Link to comment Share on other sites More sharing options...
Windspeed Posted February 14, 2015 Author Share Posted February 14, 2015 18z GFS at 72 hours: Link to comment Share on other sites More sharing options...
Stovepipe Posted February 14, 2015 Share Posted February 14, 2015 Robert's latest: Link to comment Share on other sites More sharing options...
ShawnEastTN Posted February 14, 2015 Share Posted February 14, 2015 18Z GFS out to 72 hours. Its pretty progressive as a slider again to this point, most snow is over, still though some snow showers around in the NW flow at H72. Edit: Windspeed beat me to it. Link to comment Share on other sites More sharing options...
Windspeed Posted February 14, 2015 Author Share Posted February 14, 2015 Still a lot can change, but looking at repeated runs of each model, the realization that the same system could produce 6+ inches of snow in Memphis as well as the Tri-Cities is pretty amazing. When's the last time that happened? Are we talking the 1970s? Link to comment Share on other sites More sharing options...
Stovepipe Posted February 14, 2015 Share Posted February 14, 2015 Another view of the 18z GFS snow, you can probably add at least an inch to that as cobb has consistently been 1 to 1.5 higher than 11:1 ratio. Link to comment Share on other sites More sharing options...
Jed33 Posted February 14, 2015 Share Posted February 14, 2015 Last time I know of 6+ over all or most of the state was Jan 1988 and it was a southern slider Link to comment Share on other sites More sharing options...
ShawnEastTN Posted February 14, 2015 Share Posted February 14, 2015 Looking at the GFS the second storm for later next week looks very suspiciously similar in set up to our current storm out to 138... Just a side note... Link to comment Share on other sites More sharing options...
Greyhound Posted February 14, 2015 Share Posted February 14, 2015 Why is there such a discrepancy between the Cobb, SREF and Meteograms? Cobb shows about 5.2, SREF approx 10, and Meteogram is about 4. Or am I not looking at it correctly? (Oh.....I'm looking at Knoxville//TYS). Link to comment Share on other sites More sharing options...
Stovepipe Posted February 14, 2015 Share Posted February 14, 2015 LOL GFS total after the Friday hit: Link to comment Share on other sites More sharing options...
Stovepipe Posted February 14, 2015 Share Posted February 14, 2015 Why is there such a discrepancy between the Cobb, SREF and Meteograms? Cobb shows about 5.2, SREF approx 10, and Meteogram is about 4. Or am I not looking at it correctly? (Oh.....I'm looking at Knoxville//TYS). What meteogram site are you using? Link to comment Share on other sites More sharing options...
Greyhound Posted February 14, 2015 Share Posted February 14, 2015 http://www.meteor.iastate.edu/~ckarsten/bufkit/image_loader.phtml?site=ktys&nam=on&nam_mos=on&namm=on&gfs_mos=on&gfs=on&gfsm_mos=on&gfsm=on&nws=on&rap=on&obs=on&nam4km=on&con=on&ratio=11&max_t=on&cobb=on&compaction=on&mean_mt=on&max_mt=on&mean=on Link to comment Share on other sites More sharing options...
Greyhound Posted February 14, 2015 Share Posted February 14, 2015 On the meteogram and sref I was quoting the averages Link to comment Share on other sites More sharing options...
Stovepipe Posted February 14, 2015 Share Posted February 14, 2015 On the meteogram and sref I was quoting the averages Cobb is just a snow algorithm that is applied to the NAM and GFS text output, that Iowa state site has another snow algorithm "Max T Prof". SREF is a different suite of models altogether. So it's reasonable that the meteograms show different amounts for different models. Link to comment Share on other sites More sharing options...
Stovepipe Posted February 14, 2015 Share Posted February 14, 2015 Just glanced at the euro ensembles for TYS. ALL members are over 6 inches, 35 are over 10 inches for the 15 day period. That is just freaking insane for this area. Link to comment Share on other sites More sharing options...
ShawnEastTN Posted February 14, 2015 Share Posted February 14, 2015 Just glanced at the euro ensembles for TYS. ALL members are over 6 inches, 35 are over 10 inches for the 15 day period. That is just freaking insane for this area. Yeah I really expect when MRX updates to Winter Storm Warning, they'll also up snow totals from their 3-6 they are advertising. I think they are still being conservative and rightfully so, but there is so much data screaming that 6-10" is more appropriate for storm totals at this point. When SREF means are at 10", I have to ask myself why they say 6" as a high end, other than playing for more time and models, to up the totals closer to event start time. Link to comment Share on other sites More sharing options...
ShawnEastTN Posted February 14, 2015 Share Posted February 14, 2015 WBIR in Knoxville forecasting up to 8" in the valley. Link to comment Share on other sites More sharing options...
Windspeed Posted February 14, 2015 Author Share Posted February 14, 2015 Of the multiple could have been events that have failed to resolve this winter, I have spent the better part of the past week on the extreme side of cautious optimism. However, at 36 hours out, the synoptics show a storm that should be a real producer. The model consensus continues to look like a winner. You can never rule out a bust, but at this point, if the I-40 corridor was to miss out on a significant accumulation of snow, I'd have to say a non-event would go down as one of the worst model performances in recent memory, if not the biggest winter bust the Mid-south, more specifically the state of Tennessee has seen in recent memory. To be more precise, I think if you want snow and you live anywhere near I-40 from Little Rock to Asheville, you're going to have a banner week. Link to comment Share on other sites More sharing options...
ShawnEastTN Posted February 14, 2015 Share Posted February 14, 2015 Believe that our northern energy piece has just crossed into the US out of Canada. Link to comment Share on other sites More sharing options...
Stovepipe Posted February 15, 2015 Share Posted February 15, 2015 For the record, 18z GEFS snow mean: Link to comment Share on other sites More sharing options...
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