fxus64 kmrx 200709 

Area forecast discussion 
National Weather Service Morristown Tennessee 
309 am EDT sun may 20 2018 

Short term...(today and tonight)... 

Most of the precipitation has come to an end early this morning 
with just a few isolated showers. The weak upper level trough from 
yesterday is now well to the east with a weak ridge moving into 
the area. With the widespread rainfall yesterday, expect there 
will be areas of patchy fog this morning with some patchy dense 
fog possible as well. Any fog should mix out shortly after 

For today, expect the weak low amplitude ridge to be the main focus. 
Further to the south, there is a closed low that will be located 
along the northeastern Gulf of Mexico. The GFS model soundings 
indicate a cap across most of the valley throughout the day. The NAM 
is more aggressive with moisture across the area and the 
soundings do not have a cap. Regardless, there will not be an 
obvious lifting mechanism today. Therefore, have gone with slight 
chance to chance pops across the area. The chance pops will be 
across the higher elevations of the southern appalchians and 
Cumberland Plateau where there could be some additional orographic 
lift. The NAM soundings are impressive with the SBCAPE values in 
the 2000-3000 j/kg range with the GFS being more reasonable in the 
750-1500 j/kg range. Regardless, the upper level flow will be 
weak with 0-6 km shear less than 15 kts. Therefore, not expecting 
any strong to severe storms this afternoon. Coverage and intensity 
will decrease after sunset with the lack of any forcing. High 
temperatures today will range from mid to upper 80s for most 
locations with lows tonight in the 60s. 

Long term...(monday through saturday)... 

Mid level ridging will continue to build in early next week and we 
can expect to see somewhat similar weather to what we've seen the 
past few days, with partly cloudy skies and scattered to isolated 
showers and thunderstorms. Moisture will continue to be brought in 
from the Gulf as the ridge builds in and cloudy skies and 
precipitation chances will remain through most periods the first 
half of the week. During the middle of the week a frontal boundary 
will move in from the south and possibly push into the forecast 
area. Current forecast models are trying to suggest that the front 
is able to push south of the forecast area and keep US relatively 
dry with more northerly flow. So have gone ahead and tapered down 
precipitation chances, but models have not been very consistent with 
this frontal boundary, so certainty in this is somewhat low at this 

Front will lift back north towards the end of the work week and the 
moist southerly winds will return leading to an uptick in 
precipitation chances once again. During this upcoming 7 days 
temperatures will generally top out in the mid to upper 80's which 
is about 5-10 degrees above normal for this time of year. 



Preliminary point temps/pops... 
Chattanooga Airport, Tennessee 88 68 82 66 / 30 20 60 30 
Knoxville McGhee Tyson Airport, Tennessee 86 67 81 64 / 20 20 60 30 
Oak Ridge, Tennessee 87 66 83 65 / 20 20 60 30 
Tri Cities Airport, Tennessee 84 63 82 62 / 20 20 60 40 


Mrx watches/warnings/advisories... 

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