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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