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

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000 FXUS64 KMRX 050756 AFDMRX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 356 AM EDT THU MAY 5 2016 .SHORT TERM (TODAY THROUGH TONIGHT)...IMPRESSIVE LATE SEASON LOW PRESSURE DROPPING DOWN INTO THE FORECAST AREA. CENTER OF UPPER LOW WILL PASS DIRECTLY OVER NETN AND SWVA TO START THE PERIOD AND BRING THE COLDEST 850 TEMPS THUS FAR FOR THIS EVENT. PROXIMITY TO TROUGH BASE AND LOW CIRCULATION ALLOWS A STRONG VORTICITY FIELD TO ROTATE THROUGH THE CWA. WITH THIS LOW ANOTHER BOUT OF MOISTURE ALSO MOVES IN. MOISTURE COMBINED WITH GOOD UPPER LEVEL DYNAMICS WILL ALLOW FOR LIKELY POPS ACROSS THE CENTRAL VALLEY EARLY IN THE PERIOD. NAM ALONG WITH OTHER HI-RES SOUNDINGS SUPPORTIVE OF SNOW ABOVE 4000/4500 FEET AS THIS ACTIVITY MOVES THROUGH. PRECIP MOVES INTO THE NORTHERN PLATEAU AROUND 12Z AND EXITS ACROSS OUR EASTERN MOUNTAINS AROUND 21Z. BEST WINDOW FOR SNOW ACROSS THE HIGH PEAKS OF OUR EASTERN MOUNTAINS LOOKS TO BE FROM 15Z THROUGH ABOUT 20/21Z. DURING THIS STRETCH...ELEVATIONS ABOVE 5K FEET SHOULD PICK UP AROUND AN INCH OF SNOW WITH LITTLE TO NO ACCUMULATION AROUND THE 4000/4500 FOOT MARK. AGAIN...SNOW OPPORTUNITY AND OVERALL PRECIP CHANCES DECREASE AFTER 20/21Z AS THE CENTER OF THE LOW DROPS DOWN INTO THE CAROLINAS. THIS WILL LEAVE US WITH A BREAK IN THE PRECIPITATION DURING THE LATE AFTERNOON HOURS AND SOME PARTIAL CLEARING. AS THE LOW MOVES FURTHER SOUTHEAST INTO THE CAROLINAS WRAP AROUND MOISTURE BEGINS TO ENTER SWVA AND NETN. THIS IS WHERE PRECIP CHANCES WILL BE HIGHEST OVERNIGHT. AS THIS WRAP AROUND MOISTURE MOVES IN THERE WILL BE ANOTHER BRIEF OPPORTUNITY FOR SOME LIGHT SNOW ABOVE 5000 FEET...WITH UP TO HALF AN INCH OF ACCUMULATION POSSIBLE. HIGH TEMPERATURES TODAY WILL RUN 15 TO 20 DEGREES BELOW NORMAL. HIGHS WILL RANGE FROM THE LOW 60S SOUTHERN VALLEY TO UPPER 40S/LOW 50S ACROSS SWVA. OVERNIGHT LOWS EXPECTED TO BE A DEGREE OR TWO WARMER THAN LAST NIGHT WITH LOWS IN THE LOW TO MID 40S. .LONG TERM (FRIDAY THROUGH WEDNESDAY)...UNSEASONABLY COLD UPPER LOW WILL BE LOCATED ACROSS THE MID-ATLANTIC STATES FRIDAY. THE COLD AIR ALOFT...OROGRAPHIC LIFT...AND SOME LOW-LEVEL CONVERGENCE WILL PRODUCE SCATTERED SHOWERS OVER SOUTHWEST VIRGINIA AND NORTHEAST TENNESSEE. THE UPPER LOW GETS PICKED UP BY A CANADIAN UPPER TROUGH. SHORT-WAVE ENERGY FROM THE NORTHERN STREAM UPPER LOW WILL MOVE ACROSS THE OHIO VALLEY ALONG WITH A FRONTAL BOUNDARY. THIS BOUNDARY WILL FOCUS LIMITED INSTABILITY TO PRODUCE SCATTERED SHOWERS OVER SOUTHWEST VIRGINIA...NORTHERN PLATEAU...AND NORTHEAST TENNESSEE FOR LATE SATURDAY THROUGH SUNDAY. FOR TUESDAY AND WEDNESDAY...UPPER FLOW BECOMES SOUTHWESTERLY WITH A SERIES OF SHORT-WAVES MOVING ACROSS THE TENNESSEE VALLEY. SHOWERS AND THUNDERSTORMS CAN BE EXPECTED. WILL NEED TO MONITOR HOW MUCH MOISTURE AND INSTABILITY ADVECTS INTO THE TENNESSEE VALLEY. STRONG TO SEVERE STORMS ARE POSSIBLE. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 63 47 73 50 / 30 10 0 0 KNOXVILLE MCGHEE TYSON AIRPORT, TN 57 46 69 49 / 60 50 10 10 OAK RIDGE, TN 58 46 70 49 / 60 30 10 0 TRI CITIES AIRPORT, TN 55 43 63 46 / 80 70 40 20 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$

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