Area Forecast Discussion

FXUS63 KIWX 200700
Area Forecast Discussion
National Weather Service Northern Indiana
300 AM EDT Fri Jul 20 2018
Issued at 300 AM EDT Fri Jul 20 2018
An isolated shower or storm this morning over northeast Indiana and 
northwest Ohio will give way to numerous showers and storms this 
afternoon...some of which could be strong to severe. High temps will 
top out around 80. 
.SHORT TERM...(Today and Tonight)
Issued at 300 AM EDT Fri Jul 20 2018
Linear squall line progressing through srn IL hampering convective 
development here locally this morning as it subdues better low level 
moisture flux/theta-e advection as evident in strong subsidence seen 
in GOES 16 water vapor. Eventual decay of this convection should 
yield further newd development toward daybreak through ecntrl IN/nw 
OH. Otherwise primary development not anticipated til early aftn 
tied to vigorous sw disturbance ovr nrn IA wrapping through srn 
periphery of upper low and progged into far nw IN by 18Z. At least 
partial insolation expected prior with conditional svr risk (wind) 
tied to degree of realized sfc based destabilization as effective 
shear adequate to support organized convection. However better svr 
prospects along with some tor risk seen further south into cntrl IN 
where stronger mid level flow overlaps channel of backed sfc flow 
and where greater sfc based instability should manifest. 
Nevertheless approach of upper low and continued forcing aloft will 
keep threat of showers going overnight especially nw half in 
proximity to upper low.
.LONG TERM...(Saturday through Thursday)
Issued at 300 AM EDT Fri Jul 20 2018
Upper low over srn lake MI to start the period will quickly drop swd 
into the TN valley by late Sun. Decent deformation based forcing 
expected Sat within as yet still vigorous circulation aloft. 
Thereafter feature opens up and weakens with general drying 
spreading n-s following across the area Sun. Consensus blend 
generally accepted here with decaying shower threat with time late 
Sat night through Sun evening.
Thereafter followed EC/GEM composite taking associated mid level 
trough influence east which has been the going trend as GFS 
continues to to suffer from its typical convective feedback. Mon/Tue 
aftn pops could be dropped yet will hold for another model 
.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 153 AM EDT Fri Jul 20 2018
2 areas of concern for convection for this forecast period. The 
first will be from roughly 08-16Z when models hint at uptick in 
convection mainly at KFWA. Looks to be rather isolated at first but 
could expand further if the models are correct. Better chance for 
storms will likely reside after 18Z at both sites with peak heating 
and approach of better upper levels support and wind fields. Have 
went slightly more aggressive with storms this afternoon with 
everything wrapping up by 00Z Sat. There will be changes to the TAFs 
in later forecasts so stay tuned. 
Could see some stratus and fog around if airports see enough 
rainfall after 02Z.
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