Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
226 FXUS64 KMRX 110849 AFDMRX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 349 AM EST THU FEB 11 2016 .SHORT TERM (TODAY THROUGH FRIDAY NIGHT)...FOR EARLY THIS MORNING...WEAK ISENTROPIC LIFT WILL PRODUC LIGHT SNOW/FURRIES ACROSS NORTHEAST TENNESSEE/SOUTHWEST VIRGINIA. ONLY A DUSTING OF SNOW POSSIBLE. BY THIS AFTERNOON...CLOUDS DISSIPATE WITH RETURN OF SUNSHINE. FOR TONIGHT...A FAST MOVING JET WILL DIVE SOUTHEAST TOWARD THE AREA PLACING NORTHEAST TENNESSEE/SOUTHWEST VIRGINIA UNDER THE FAVORED RIGHT ENTRANCE REGION OF THE JET WITH WEAK CYCLOGENESIS. FOR FRIDAY...AN AREA OF LIGHT SNOW WILL DEVELOP OVER THE NORTHERN HALF OF THE AREA EARLY FRIDAY MORNING. SNOW WILL LIKELY BECOME A MIXTURE IN THE MORNING AND AFTERNOON. ACROSS THE SOUTHERN HALF OF THE AREA...ALONG AND SOUTH OF INTERSTATE 40...WILL BE SOUTH OF THE CYCLOGENESIS WITH MILDER AIR AND LITTLE TO NO PRECIPITATION. FOR LATE FRIDAY/FRIDAY NIGHT...ARCTIC FRONTAL BOUNDARY MOVES BACK ACROSS THE AREA IN THE AFTERNOON/EVENING WITH NORTHWEST FLOW UPSLOPE SNOW THROUGH MIDNIGHT FRIDAY NIGHT. LIGHT SNOW ACCUMULATIONS EXPECTED. .LONG TERM (THURSDAY THROUGH TUESDAY)... VERY TRICKY FORECAST IN THE EXTENDED PERIOD...AS ATTENTION TURNS TO THE POSSIBILITY FOR ANOTHER WINTER STORM BEGINNING LATE SUNDAY NIGHT THROUGH MONDAY NIGHT. THE FORECAST FOR THIS PERIOD IS STILL HIGHLY UNCERTAIN...GIVEN THE MODEL DIFFERENCES ON TIMING...THE VERTICAL TEMPERATURE PROFILE...AND PRECIPITATION TYPE AND DURATION FOR THIS EVENT. MOST MODELS GENERALLY SHOW THE ONSET OF PRECIPITATION BEING ALL SNOW...FOLLOWED BY A WARM-UP DURING THE DAY ON MONDAY /PRESIDENT`S DAY/...CHANGING SNOW TO MIX OF SNOW/RAIN...FOLLOWED BY A CHANGE BACK TO ALL SNOW LATE IN THE EVENT MONDAY NIGHT. THE ECMWF SHOWS A WEAKER SURFACE AND 850 MB LOW MUCH FURTHER NORTH /ALMOST DIRECTLY OVER THE I-40 CORRIDOR/...WITH PRECIPITATION BEGINNING MUCH EARLIER...JUST AFTER MIDNIGHT SUNDAY NIGHT. THIS WOULD ALLOW PRECIPITATION AT THE ONSET TO POTENTIALLY BEGIN AS MODERATE TO LOCALLY HEAVY SNOW...BEFORE CHANGING OVER TO A FREEZING RAIN/SNOW/RAIN MIX DURING THE AFTERNOON OVER MUCH OF THE VALLEY...AND EVENTUALLY LIGHT SNOW ON THE BACK SIDE MONDAY NIGHT. THE GFS SHOWS PRECIPITATION BEGINNING SLIGHTLY LATER ON MONDAY MORNING...BEGINNING AS SNOW AND THEN POSSIBLY MIXING WITH RAIN...SLEET OR FREEZING RAIN DURING THE AFTERNOON...BEFORE TRANSITIONING OVER ALL MODERATE TO HEAVY SNOW MONDAY NIGHT AS THE 850 MB LOW TRACKS INTO THE NORTH GEORGIA MOUNTAINS. THIS SOLUTION WOULD PLACE PORTIONS OF THE EASTERN TENNESSEE VALLEY AND THE EAST TENNESSEE AND NORTH CAROLINA MOUNTAINS UNDERNEATH THE TROWEL REGION...AND SUPPORT A WIDESPREAD MODERATE TO HEAVY SNOW MONDAY NIGHT...BEFORE TAPERING OFF TUESDAY MORNING. AN EXAMINATION THE VERY STRONG Q-VECTOR CONVERGENCE DIRECTLY OVER THE GREAT SMOKY MOUNTAINS AT 06Z THURSDAY CONFIRMS THIS. GIVEN THE DIFFERENCES OUTLINED ABOVE...HAVE NOT GOTTEN TOO SPECIFIC WITH PRECIPITATION TYPE OR AMOUNTS GIVEN THAT THIS IS A LOW CONFIDENCE FORECAST. HOWEVER...CONFIDENCE IS REASONABLY HIGH THAT MOST/ALL OF THE REGION WILL EXPERIENCE SNOW AND POTENTIALLY OTHER FORMS OF WINTRY PRECIPITATION SOMETIME DURING THE MONDAY AND MONDAY NIGHT TIMEFRAME. ADDITIONALLY...HIGHER CONFIDENCE EXISTS REGARDING THE POSSIBILITY FOR A SIGNIFICANT SNOWFALL ALONG THE EAST TENNESSEE AND NORTH CAROLINA MOUNTAINS...AND PERHAPS PORTIONS OF FAR NORTHEAST TENNESSEE AND SOUTHWEST VIRGINIA. HOWEVER...A MUCH LOWER CONFIDENCE EXISTS REGARDING SPECIFIC DETAILS FOR SNOWFALL AMOUNTS AND PRECIPITATION TIMING/TYPE FOR MUCH OF THE VALLEY /INCLUDING THE KNOXVILLE AND CHATTANOOGA METRO AREAS/...AND THE CUMBERLAND PLATEAU. PLEASE STAY WEATHER AWARE THIS WEEKEND...AND MONITOR THE LATEST FORECAST INFORMATION FROM THE NATIONAL WEATHER SERVICE REGARDING THIS STORM SYSTEM...ESPECAILLY IF YOU HAVE TRAVEL PLANS! IN WAKE OF THIS SYSTEM...MODELS SHOW A RETURN TO SOUTHERLY FLOW AS AN UPPER-LEVEL HIGH PRESSURE RIDGE LOOKS TO BUILD INTO THE TENNESSEE VALLEY FOR THE LATER HALF OF THE WEEK. THIS WILL ALLOW FOR MORE SUNSHINE AND HIGH TEMPERATURE TO GRADUALLY REBOUND INTO THE 50S AND PERHAPS WELL INTO THE 60S TOWARD THE END OF THE WORK WEEK. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 45 29 53 25 / 0 10 10 0 KNOXVILLE MCGHEE TYSON AIRPORT, TN 39 27 45 23 / 0 20 40 10 OAK RIDGE, TN 37 26 45 21 / 0 20 40 10 TRI CITIES AIRPORT, TN 33 22 37 19 / 0 20 60 40 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR BLOUNT SMOKY MOUNTAINS-COCKE SMOKY MOUNTAINS-JOHNSON-SEVIER SMOKY MOUNTAINS-SOUTHEAST CARTER-SOUTHEAST GREENE-SOUTHEAST MONROE-UNICOI. VA...NONE. && $$

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.