National Weather Service Raw Text Product

Displaying AFOS PIL: AFDIWX Received: 2017-10-13 06:12 UTC

FXUS63 KIWX 130612

Area Forecast Discussion
National Weather Service Northern Indiana
212 AM EDT Fri Oct 13 2017

Issued at 212 AM EDT Fri Oct 13 2017

Mostly cloudy skies and patchy fog will prevail early this morning 
with temps in the 50's. Clouds will diminish some this afternoon 
especially south of US 30 as high pressure briefly settles over the 
area. Another system will bring chances for rain far northwest 
Indiana and southwest Michigan late tonight into Saturday morning. 

Highs this afternoon will range in the upper 60s to 70. Much warmer 
weather is expected for Saturday with highs climbing into the mid-
upper 70's. A period of showers will cross the region late Saturday 
night into Sunday morning as a sharp cold front moves through the 
area with falling temperatures through the 50s expected Sunday.


.SHORT TERM...(Today and Tonight)
Issued at 212 AM EDT Fri Oct 13 2017

Sharp subsident inversion continues across the lakes/OH valley this 
morning and manifested by persistent stratus plaguing the area. 
However upstream breaks across IL promise some partial insolation 
potential this aftn over sw half. Nevertheless glaring mos based 
downward trending temp guidance warrants cutting max temps this aftn.

Primary attention going forward lies with pacnw sw trough amplifying 
through the nrn Rockies tonight and subsequent ewd carry through the 
nrn lakes Sun. Downstream advective/moisture push newd of organizing 
frontal wave through IA Sat dictate a sharper sewd cutoff to pops 
late tonight.


.LONG TERM...(Saturday through Thursday)
Issued at 212 AM EDT Fri Oct 13 2017

Strong model based consensus now with both upstream sw evolution 
aloft and more importantly attendant frontal positioning to start 
this period on Sat. Seasonably strong intensification of sfc cyclone 
lifting from sw IA Sat aftn through nrn lower MI late Sat night 
warrant sharp ewd reductions in prior pop extent Sat day/night. 
Otherwise rapid newd ejection of upper wave into wrn QB Sun allows 
trailing cold frontal zone to surge ewd Sun morning with further pop 
reductions w-e warranted Sun morning. Sharp/pronounced low level 
cold advection wing likely to result in falling temps through the 
day Sun with chilly weather persisting through Mon as sfc ridge 
settles into the lower OH valley. Some frost is likely early Mon 
given overlap of sfc ridge axis within retreating thermal trough.

Thereafter strong thermal moderation expected as Conus flow aloft 
flattens to wrly and strong thermal ridging builds back into the 
lakes mid to late period. Will side strongly toward warmer blend of 
EC based mos guidance Wed onward.


.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 139 AM EDT Fri Oct 13 2017

Main concern tonight would be the potential return of IFR 
conditions, especially at KFWA. Weak WAA kicks in tonight ahead of a 
weak trough that will lift through. With WAA, nearly calm surface 
winds, and mid-level subsidence trapping moisture close to the 
surface, think KFWA will have a shot at developing some IFR 
conditions between 9-13Z due to BR or perhaps even fog. Have 
introduced a tempo group to cover this for now, and went 
conservative on the visibilities given uncertainty. Winds will be 
stronger over KSBN, thus potential is lower for IFR conditions, 
so have kept things MVFR for now. There is a chance that there 
could be some drizzle again with the passage of this weak trough, 
but did not include in the TAF for now given low confidence. We 
return to VFR conditions late Friday morning/early afternoon.





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