Elvin Harkins Posted February 15, 2015 Share Posted February 15, 2015 NWS Louisville now says up to 18" snow possible in Central Kentucky Link to comment Share on other sites More sharing options...
jaxjagman Posted February 15, 2015 Share Posted February 15, 2015 Can anyone explain why the precip is more, temps colder at all levels, but snow is less? Hey Jax, I am confused. The text data you posted for TRI shows a great thermal setup and plentiful qpf, but the americanwx model suite maps are totally different. Shows borderline thermals and almost 1/2 of the qpf. Where do you get those? Can a met tell me why they would be different? wouldnt pay attention to the small details,tri looks fine,the only warm nose in details would be at 1k feet,your verticals look good Link to comment Share on other sites More sharing options...
ShawnEastTN Posted February 15, 2015 Share Posted February 15, 2015 WPC preferred Tracks... Imagine if the low follows the lowest cluster in AL and GA in this image. That alone could affect p-type and amount of snow for a lot of people. I understand why MRX says in the AFD that confidence is low in p-type. Link to comment Share on other sites More sharing options...
Stovepipe Posted February 15, 2015 Share Posted February 15, 2015 18z rgem came in a hair south of its previous run with all precip types. Still an epic ice storm for much of the state with northern border counties crushed with snow. Link to comment Share on other sites More sharing options...
Carvers Gap Posted February 15, 2015 Share Posted February 15, 2015 For posterity... Link to comment Share on other sites More sharing options...
Windspeed Posted February 15, 2015 Author Share Posted February 15, 2015 Link to comment Share on other sites More sharing options...
jaxjagman Posted February 15, 2015 Share Posted February 15, 2015 wouldnt pay attention to the small details,tri looks fine,the only warm nose in details would be at 1k feet,your verticals look good LOW LEVEL.png Blah,this isnt right Hey Jax, I am confused. The text data you posted for TRI shows a great thermal setup and plentiful qpf, but the americanwx model suite maps are totally different. Shows borderline thermals and almost 1/2 of the qpf. Where do you get those? Can a met tell me why they would be different? its not right,just noticed its not updated ,when it should have Link to comment Share on other sites More sharing options...
John1122 Posted February 15, 2015 Share Posted February 15, 2015 It's gonna be a tight one for us all as far as snow goes. A shame this thing has trended to such a mess after a week of great model runs. Link to comment Share on other sites More sharing options...
ShawnEastTN Posted February 15, 2015 Share Posted February 15, 2015 gfs_asnow_seus_9.png The clown itself looks a little better. Link to comment Share on other sites More sharing options...
Windspeed Posted February 15, 2015 Author Share Posted February 15, 2015 Link to comment Share on other sites More sharing options...
jaxjagman Posted February 15, 2015 Share Posted February 15, 2015 AREA FORECAST DISCUSSIONNATIONAL WEATHER SERVICE NASHVILLE TN350 PM CST SUN FEB 15 2015 .DISCUSSION... THIS FORECAST WAS INCREDIBLY DIFFICULT AS MODELS TRACKED THESURFACE LOW AND WARMER AIR FARTHER NORTH OVERNIGHT AND FOR THEMORNING RUNS...IN ADDITION TO MAKING THE FORECAST HAVE MANY MOREUNCERTAINTIES WITH SNOWFALL TOTALS AND AREAS OF PRECIP TYPE. THENORTHERN TRACK OF THE LOW ALSO PUSHED THE MIXED PRECIP CHANCESNORTHWARD AND FORCED A LARGE SNOWFALL TOTAL GRADIENT ACROSS THECWA FROM SOUTH TO NORTH. THIS AFTERNOONS FORECAST PUTS AROUND ANINCH OR LESS IN THE FAR SOUTH...AND UP TO 11 INCHES NEAR THEKY/TN BORDER. THIS IS LARGELY DUE TO THE MIXED PRECIP ROBBING SOMEOF THE MOISTURE AND THUS SNOWFALL AMOUNTS AS YOU GET FARTHERSOUTH. AS FOR TIMING...MODELS HAVE ALSO INDICATED THE PRECIP WILL BEGINSLIGHTLY LATER THAN PREVIOUS RUNS. BACKED OFF ON THE WARNING UNTIL06Z AND THINGS STILL MAY NOT GET GOING ACROSS THE CWA UNTIL 12Z.SNOW WILL LIKELY START IN THE NORTHWEST AFTER MIDNIGHT AND FINALLYAT THE EASTERN EDGE LATER IN THE MORNING. DECIDED TO EXTEND THEWARNING UNTIL 06Z SINCE SNOWFALL MAY STILL BE ONGOING IN THENORTHWEST AFTER 00Z. MOST OF THE AREA SHOULD BE OUT OF HARMS WAYBY THEN BUT DID NOT WANT TO COUNT OUT THE EASTERN ZONES STILLHAVING CHANCES FOR IMPACTFUL PRECIP. LOOKING AT THE MODEL DATA FOR THIS EVENT...THERE IS PRETTY GOODAGREEMENT ON 850MB TEMPS...SURFACE WET BULB TEMPERATURES...ANDEVEN TIMING. UNFORTUNATELY THERE ARE SLIGHT VARIATIONS THAT MAYMAKE THE CENTRAL PART OF THE CWA HIT OR MISS WITH SNOWFALLAMOUNTS. THE NAM LOOKS TO BE THE WARMEST...WITH 850MB TEMPS ABOVE0C AS FAR NORTH AS THE KY/TN BORDER AT 18Z. THE EURO IS RIGHT INTHE MIDDLE OF THE CWA WITH 850MB ZERO LINE AROUND I40...AND THE GFSIS RIGHT BETWEEN. LOOKING AT MODEL SOUNDINGS...AREAS NEAR THEKY/TN BORDER ARE LIKELY TO SEE SNOW WITH ONLY SLIGHT CHANCES FORSLEET. IN THE CENTRAL PART OF THE CWA...THERE LOOKS TO BE A MIXTHANKS TO A STRONGER INDICATION OF A WARM NOSE AT AROUND 3-4C BYMID MORNING THROUGH THE AFTERNOON. THIS WILL LIKELY MELT THE SNOWTO SLEET. SOME CONCERN MAY BE IF THE MELTING OF THE SNOW WILLCONTRIBUTE TO COOLING THE WARM NOSE A BIT...SO KEPT MENTION OFSNOW AND THINK THAT A MIX WILL CONTINUE THROUGH THE DAY FORCENTRAL AREAS. QPF VALUES ARE QUITE HIGH FOR THE 12Z- 00ZTIMEFRAME...SO THE SLEET COULD CONTRIBUTE TO THE OVERALL SNOWFALLACCUMULATIONS AS WELL. AS YOU GET FARTHER SOUTH...THE DEPTH OF THECOLD AIR BELOW THE WARM NOSE DECREASES AND THUS LOOKS TO BEPRIMARILY FREEZING RAIN. SURFACE TEMPERATURES GET ABOVE 0C DURINGTHE AFTERNOON FOR THE FAR SOUTH SO PUT MENTION OF RAIN WITH THEFREEZING RAIN. SURFACE WET BULB TEMPERATURES REMAIN BELOW 32F FORMOST OF THE SOUTH PER MODEL CONSENSUS SO WENT WITH A FREEZING RAINDOMINANT WX GRID WITH MENTIONS OF SLEET. HOWEVER...A TRACK FARTHERNORTH OR SOUTH WITH THE WARM AIR WILL DRAMATICALLY IMPACT NOT ONLYPRECIP TYPE BUT FINAL SNOWFALL TOTALS. LOOKING AT CROSS SECTIONSBETWEEN MODELS...A HEAVY SNOW SETUP MAY FALL INTO PLACE WITH VERYHIGH OMEGA VALUES LINED UP PERFECTLY WITH THE DENDRITIC GROWTHZONE NORTH OF THE TN/KY BORDER. COMBINED WITH THE HIGHMOISTURE...UPPER LEVEL SUPPORT AND TEMPERATURE SUPPORT FOR SNOW INTHE LOW LEVELS...HEAVY SNOW SEEMS LIKELY FOR THE NORTHERN 1/4 OFTHE CWA. AGAIN...IF THE SURFACE LOW AND WARM AIR TRAVEL FARTHERSOUTH...THE DOMINANT SNOW BAND COULD PUSH FARTHER SOUTH AS WELLAND IMPACT NASHVILLE AND THE I40 CORRIDOR. IF THAT HAPPENS THENSNOWFALL AMOUNTS WILL LIKELY BE ON THE LOW SIDE WITH THE CURRENTFORECAST. AS FOR ICE ACCUMULATIONS IN THE SOUTH...MAINLY KEPTACCUMULATIONS BELOW A QUARTER INCH SINCE IT IS UNCERTAIN JUST HOWWARM THE AREA WILL GET. THERE MAY BE ICE ACCUMULATION BEFORE18Z...THEN PRIMARILY RAIN DURING THE AFTERNOON. HOWEVER...IFTEMPERATURES REMAIN COLD FOR THE DAY...THEN ICE ACCUMULATIONS FORTHIS FORECAST WILL BE VERY LOW AND A SIGNIFICANT INCREASE IN THEAMOUNT OF ACCUMULATING ICE MAY OCCUR. AS FOR THE REST OF THE PERIOD...THE COLD WILL REMAIN. LINGERINGCHANCES FOR SNOW WILL POP INTO THE FORECAST AS WELL AS THE UPPERLEVEL PATTERN WILL NOT GIVE UP ON THE TROUGHS IMPACTING THE EAST.THURSDAY LOOKS TO BE THE COLDEST DAY WITH YET ANOTHER COLD SHOT TOREINFORCE THE COLD AIR ALREADY IN PLACE. 850MB TEMPS WILL BE ASCOLD AS -24C BY THURSDAY MORNING. LOWERED TEMPS A BIT FURTHER PASTGUIDANCE AS SNOW COVER COMBINED WITH THE COLD AIR IN THE LOWLEVELS WILL LIKELY BRING LOWS IN THE SINGLE DIGITS BELOW ZERO. ANYWIND WHATSOEVER WILL LIKELY BRING WIND CHILL ADVISORY CRITERIA TOTHE CWA. BY SATURDAY...850MB TEMPS GET ABOVE 0C AS THE NEXT UPPERSHORTWAVE BRINGS SOME WAA AND POSSIBLY HIGHS INTO THE 40S FOR THEFIRST TIME THIS WEEK. EITHER WAY...BELOW AVERAGE TEMPERATURES AREHERE TO STAY THROUGH NEXT WEEKEND AND INTO THE WORK WEEK. && Link to comment Share on other sites More sharing options...
ShawnEastTN Posted February 15, 2015 Share Posted February 15, 2015 rgem_asnow_seus_16.png That is probably going to be the most accurate snowfall map if sleet and freezing rain are removed from the equation. Link to comment Share on other sites More sharing options...
ShawnEastTN Posted February 15, 2015 Share Posted February 15, 2015 One take away form both MRX and OHX discussions... Neither are confident on p-types, both appear open to wiggles in track that could affect p-type and subsequent accumulation forecasts. I guess we'll be essentially just watching what happens, where the low tracks, and what obs are occurring. Link to comment Share on other sites More sharing options...
John1122 Posted February 15, 2015 Share Posted February 15, 2015 OHX pretty much kept heavy snow in their 40 and north areas. Especially along the border. Also in that AFD posted above they mention that the models may be overdoing the warming. Models often do, especially surface warming during heavy precip events. Link to comment Share on other sites More sharing options...
jaxjagman Posted February 15, 2015 Share Posted February 15, 2015 One take away form both MRX and OHX discussions... Neither are confident on p-types, both appear open to wiggles in track that could affect p-type and subsequent accumulation forecasts. I guess we'll be essentially just watching what happens, where the low tracks, and what obs are occurring. Hard to tell,i'm thinking the text i'm i'm posting is garbage.It just dont add up to me. Link to comment Share on other sites More sharing options...
Vol Man Posted February 16, 2015 Share Posted February 16, 2015 MRX discussion video...can't remember them doing this too often in the past Link to comment Share on other sites More sharing options...
jaxjagman Posted February 16, 2015 Share Posted February 16, 2015 HRRR Model Fields Experimental.png I was hoping the HRRR would look better but the NAM shows about the same look,if the NAM is right these would start to fall shortly after Link to comment Share on other sites More sharing options...
LithiaWx Posted February 16, 2015 Share Posted February 16, 2015 Can anyone give primo chase locations in eastern half of TN. Is Crossville still the verdict? I'll probably hop in the car tomorrow morning and head up. Any suggestions for TN centric spots would be apprechiated. If this is banter please move and i apologize in advance. Link to comment Share on other sites More sharing options...
Blue Ridge Posted February 16, 2015 Share Posted February 16, 2015 As seen in the discussion video above... Link to comment Share on other sites More sharing options...
Blue Ridge Posted February 16, 2015 Share Posted February 16, 2015 Jax, did you ever figure out what happened with the NAM text output? Link to comment Share on other sites More sharing options...
Bango Posted February 16, 2015 Share Posted February 16, 2015 Can anyone give primo chase locations in eastern half of TN. Is Crossville still the verdict? I'll probably hop in the car tomorrow morning and head up. Any suggestions for TN centric spots would be apprechiated. If this is banter please move and i apologize in advance. This is one I don't know that I would chase unless you don't care to be stuck somewhere for an extended period. I can't imagine travel will be possible driving across these regions, the southern tier should have fallen trees and powerlines, the middle and northern tiers will be snow problems..if you get stuck for longer then 24 hours you will be further pinned by the light snow on Wednesday. My county has a handful of snow plows and it'll take awhile to get out of this Link to comment Share on other sites More sharing options...
jaxjagman Posted February 16, 2015 Share Posted February 16, 2015 Jax, did you ever figure out what happened with the NAM text output? No,its not updating,still stuck on 7 this morn Link to comment Share on other sites More sharing options...
jaxjagman Posted February 16, 2015 Share Posted February 16, 2015 Can anyone give primo chase locations in eastern half of TN. Is Crossville still the verdict? I'll probably hop in the car tomorrow morning and head up. Any suggestions for TN centric spots would be apprechiated. If this is banter please move and i apologize in advance. NE Tn is where u want to go Link to comment Share on other sites More sharing options...
Windspeed Posted February 16, 2015 Author Share Posted February 16, 2015 East Tennessee State University just cancelled classes for tomorrow. I'm glad. There is no reason to have anyone travelling tomorrow afternoon. The roads are going to be a nightmare in the Tri-Cities. Link to comment Share on other sites More sharing options...
John1122 Posted February 16, 2015 Share Posted February 16, 2015 I'd just go up I-75, if not my area, into Southeastern Kentucky. I'm predicted to get 6-8 inches of snow and .10 ice by Morristown. Not sure if there's just a QPF minimum over me or what, because they have much higher snow/ice totals qpf wise than both my amounts added together would equal. Link to comment Share on other sites More sharing options...
Blue Ridge Posted February 16, 2015 Share Posted February 16, 2015 I'd just go up I-75, if not my area, into Southeastern Kentucky. I'm predicted to get 6-8 inches of snow and .10 ice by Morristown. Not sure if there's just a QPF minimum over me or what, because they have much higher snow/ice totals qpf wise than both my amounts added together would equal. John, I noticed their snow and ice graphics don't match up; where the snow cuts off, the ice doesn't pick up. I suppose it could be sleet - but the differences seem arbitrary. My guess is they are trying to ensure any area that could see significant ice is covered. The difference between 6-8" and 8-10" of snow isn't that great, but the difference between no ice and .10" is very significant. Link to comment Share on other sites More sharing options...
John1122 Posted February 16, 2015 Share Posted February 16, 2015 OHX was also onto something imo about heavy snow rates helping fight against the warm nose. I can count on my hand the number of times in my entire life that heavy snow changed over to rain while precip rates were high, at least in my area. I realize that is more likely in the valley due to it's natural funnel tendency and coastal places it's pretty common too. It just never happens here. Link to comment Share on other sites More sharing options...
Blue Ridge Posted February 16, 2015 Share Posted February 16, 2015 Grasping at straws here, but per MRX's aviation update, they do believe TRI will remain mainly snow: .DISCUSSION...QUIET WEATHER FOR AVIATION INTERESTS FOR ABOUT 12-13HOURS BUT SOUTHERN PLAINS STORM SYSTEM MOVES INTO THE SOUTHEASTERNU.S. ON MONDAY. MIXED PRECIPITATION LIKELY AT CHA AND TYS AS THEMORNING PROGRESSES WITH FREEZING RAIN AND SLEET DURING THE MORNINGAT CHA WHILE TYS MAY SEE SOME SNOW TO START WITH A CHANGEOVER TOSOME FREEZING RAIN AND SLEET MID DAY INTO THE AFTERNOON. ENOUGHWARMING SHOULD TAKE PLACE TO KEEP MID TO LATE AFTERNOON PRECIP INTHE FORM OF RAIN AT CHA WHILE PRECIPITATION APPEARS TO STAY MAINLYIN THE FORM OF SNOW AT TRI WITH A POSSIBLE MIX WITH SLEET LATER INTHE DAY AS THE 85H JET AXIS BUILDS ACROSS THE CREST OF THEAPPALACHIANS. Link to comment Share on other sites More sharing options...
jaxjagman Posted February 16, 2015 Share Posted February 16, 2015 Not sure about the HRRR,looks to warm looking at the mesoscale,the NAM looks good though edit:not a huge difference to discount it Link to comment Share on other sites More sharing options...
Stovepipe Posted February 16, 2015 Share Posted February 16, 2015 HRRR p-type radar at 13z in the morning: Link to comment Share on other sites More sharing options...
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