511  
FXUS64 KMRX 030734  
AFDMRX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MORRISTOWN TN  
334 AM EDT WED JUN 3 2020  
   
SHORT TERM
 
 
THE MAIN FORECAST CONCERN FOR THE SHORT TERM PERIOD IS THIS  
AFTERNOON'S HIGH TEMPERATURE FORECAST HONESTLY. SUSPECT SOME  
ISOLATED SHOWERS WILL FORM THIS AFTERNOON IN THE SOUTH, BUT  
OTHERWISE MOST ALL OF THE FORECAST AREA WILL BE DRY AND A BIT ON  
THE WARM SIDE.  
 
WATER VAPOR SATELLITE IMAGERY SHOWS A WEAK UPPER LOW CENTERED  
OVER THE ARKANSAS AND OKLAHOMA BORDER EARLY THIS MORNING, WITH  
ANOTHER DISTURBANCE MOVING THROUGH MINNESOTA. THIS NORTHERN  
STREAM SHORTWAVE WILL DROP EAST SOUTHEAST INTO THE OHIO RIVER  
VALLEY BY THIS EVENING, HELPING TO KNOCK UPPER HEIGHTS DOWN  
SIGNIFICANTLY OVER THE SOUTHERN APPALACHIAN REGION AS IT DOES SO.  
DESPITE LOWERING UPPER HEIGHTS, WITH A FAIRLY CLOUD FREE START TO  
THE DAY IT SHOULD BE ANOTHER WARM DAY. MANY PLACES SAW MID TO  
UPPER 80S YESTERDAY AFTERNOON, WHICH WAS A 2-3 DEGREE INCREASE  
OVER THE PREVIOUS DAY. WENT SLIGHTLY ABOVE NBM GUIDANCE AND MORE  
IN LINE WITH THE ECMWF OUTPUT, WHICH SUGGESTS THAT MANY VALLEY  
LOCALES AROUND AND SOUTH OF THE KNOXVILLE AREA WILL FLIRT WITH 90  
DEGREES FOR AFTERNOON HIGHS. THIS SEEMS REASONABLE, AND REALLY IS  
ONLY 1-3 DEGREES HIGHER THAN MUCH OF THE REST OF AVAILABLE  
GUIDANCE. WITH THE REGION FREE OF ANY DISCERNIBLE FORCING  
MECHANISMS, MUCH OF THE FORECAST AREA SHOULD BE DRY TODAY. THAT  
SAID, SOUTHERN PLATEAU AND SOUTHERN MOUNTAIN ZONES WILL LIKELY SEE  
A FEW ISOLATED STORMS DEVELOP BY THIS AFTERNOON. HAVE SOME 20-30  
PERCENT RAIN CHANCES IN THE FORECAST ACCORDINGLY, WITH SLIGHT  
CHANCES MENTIONED IN THE VALLEY TO ACCOUNT FOR SOME STORMS MOVING  
OFF THE HIGHER TERRAIN THIS EVENING. FURTHER NORTH I THINK THE  
CAPPING INVERSION SHOULD HOLD ENOUGH TO PRECLUDE MUCH BEYOND AN  
AFTERNOON CU FIELD DEVELOPING. HEADING BACK SOUTH...NOT EXPECTING  
MUCH IN THE WAY OF SEVERE STORMS, HOWEVER THERE IS SOME NOTABLE  
INSTABILITY PRESENT IN BUFR SOUNDING POINTS. THE MORE RESERVED GFS  
SOUNDING POINTS SHOW MUCAPE VALUES IN THE 1,500 J/KG RANGE THIS  
AFTERNOON. INTERESTING TO NOTE THAT THE MAX TEMP FORECAST CALLS  
FOR READINGS A FEW DEGREES HIGHER THAN WHAT THE GFS SOUNDINGS  
WOULD SUGGEST, SO IF THE ECMWF IS CORRECT THEN INSTABILITY COULD  
BE A TOUCH UNDERDONE THIS AFTERNOON. NEVERTHELESS, WHAT CONVECTION  
DOES FORM WILL BE OF THE PULSE VARIETY, MEANING THE MOST NOTABLE  
THREAT FROM ANY STRONGER STORMS WOULD BE DAMAGING WINDS. AGAIN  
THOUGHT, THINK THE THREAT OF SEVERE STORMS IS LOW AND WILL NOT  
MENTION IN THE HWO FOR THAT REASON. AFTER SUNSET, CONVECTIVE  
PROCESSES SHOULD DIE OFF PRETTY QUICKLY GIVEN THE LACK OF  
FORCING.  
 
TONIGHT, INCREASING CLOUDS AND A WARM MUGGY ATMOSPHERE IN PLACE  
WILL MEAN LOWS IN THE UPPER 60S TO AROUND 70. RAIN CHANCES WILL  
INCREASE TOWARDS THE START OF THE LONG TERM PERIOD AS THE  
INFLUENCE OF THE NORTHERN STREAM SHORTWAVE BEGINS TO BE FELT.  
 
CD  
   
LONG TERM...(THURSDAY THROUGH TUESDAY)
 
 
ATMOSPHERIC MOISTENING ALONG WITH STRENGTHENING DESTABILIZATION  
WILL CONTINUE THROUGH THE FIRST HALF OF THE LONG TERM AS A  
SLIGHTLY STRONGER SOUTHERLY COMPONENT TO THE LOW LEVEL FLOW  
BECOMES ESTABLISHED ON THE BACK SIDE OF A RETREATING WESTERN  
ATLANTIC RIDGE. A COUPLE OF WEAK UPPER LEVEL IMPULSES WILL BE  
BUILDING EAST OUT OF THE MIDWEST STATES TO AID IN THE ACTIVATION  
OF SCATTERED CONVECTION ACROSS THE SOUTHERN APPALACHIANS ON BOTH  
THURSDAY AND FRIDAY. MAINTAINED LIKELY POPS THROUGH THIS PERIOD,  
WITH MEDIUM THROUGH HIGH CHANCE PROBABILITY FOR A FEW SHOWERS AND  
THUNDERSTORMS AGAIN ON SATURDAY. SOME UNCERTAINTY REMAINS IN THE  
WEEKEND PERIOD PERTAINING TO THE ABILITY OF AN EASTERN U.S. COLD  
FRONT TO MAKE PROGRESS THROUGH THE SOUTHERN PORTION OF THE  
APPALACHIAN REGION. MODEL FORECASTS CONTINUE TO SHOW AN AMPLIFYING  
NORTHEASTERN U.S. UPPER TROUGH OVER THE WEEKEND, BUT THE GULF OF  
MEXICO TROPICAL STORM WILL BECOME INCREASINGLY SIGNIFICANT IN ITS  
ABILITY TO STALL THE PROGRESS OF THAT BOUNDARY. WENT AHEAD AND  
STAYED THE COURSE WITH DECREASING POPS SUNDAY INTO MONDAY IN A  
DRIER, NORTHERLY LOW LEVEL FLOW REGIME. STAYED WITH A GRADUAL  
INCREASE IN POPS FOR A FEW SHOWERS AND A THUNDERSTORM ON TUESDAY  
AS THE TROPICAL SYSTEM AND ITS MASS OF DEEP MOISTURE GET PULLED  
NORTH THROUGH THE MISSISSIPPI VALLEY AHEAD OF A PLAINS LONG WAVE  
TROUGH. AS WE APPROACH THE SOLSTICE, TEMPERATURES WILL REMAIN A  
FEW DEGREES ABOVE NORMAL THROUGH MUCH OF THE LONG TERM.  
 

 
   
AVIATION
 
 
06Z TAF DISCUSSION.  
 
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE PERIOD.  
CURRENTLY DO NOT HAVE ANY SHRA/TSRA MENTIONED AT ANY SITES BUT  
THERE IS A POSSIBILITY THAT SOME VCSH/VCTS COULD BE WARRANTED AT  
KCHA THIS AFTERNOON. UNCERTAINTIES IN COVERAGE PRECLUDE MENTIONING  
THAT AT THIS TIME HOWEVER. SOUTHWEST WINDS OF 8-10KT SHOULD BE  
SEEN AT ALL SITES TODAY. SOME GUSTS INTO THE TEENS COULD OCCUR AT  
KTRI OR KTYS BUT CONFIDENCE NOT HIGH.  
 
CD  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
CHATTANOOGA AIRPORT, TN 89 69 86 68 87 / 20 30 60 40 50  
KNOXVILLE MCGHEE TYSON AIRPORT, TN 90 69 86 68 87 / 10 30 60 40 50  
OAK RIDGE, TN 90 69 86 68 87 / 20 30 60 30 40  
TRI CITIES AIRPORT, TN 86 65 84 64 84 / 10 40 70 40 60  
 

 
   
MRX WATCHES/WARNINGS/ADVISORIES
 
 
NC...NONE.  
TN...NONE.  
VA...NONE.  

 
 

 
 
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