Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 240805

Area Forecast Discussion
National Weather Service Northern Indiana
405 AM EDT WED AUG 24 2016

Issued at 357 AM EDT Wed Aug 24 2016

Shower and thunderstorm chances will increase through Thursday
ahead of a slow moving cold front. Locally heavy rain will once
again be a concern. Highs will climb into the upper 70s to middle
80s. Lows will be in the upper 60s to around 70.


.SHORT TERM...(Today through Thursday)
Issued at 357 AM EDT Wed Aug 24 2016

Challenging forecast with respect to shower/storm chances across the
region until cold front and upper level features depart Thursday

Convection has been ongoing to some extent well back to the west
from southern Minnesota into northern Missouri. 2 areas of storms
have now merged (one moved SE out of SW Iowa, the other was in NW
Missouri). HRRR/ESRL HRRR/RAP have all handled this activity fairly
well as track it east over the next several hours. Prior to its
arrival...nose of increasing theta e air resided over central
Illinois with 30 to 40 kt low level jet just to the west. The same
models all suggest widely scattered shower (storm?) activity to
develop in the 8 to 10z window over SW areas and then move east
through 12z. Originally dismissed as noise...but recent radar echos
from Lk Michigan to Indy give some credence to having something
mentioned. Have retained a pre-1st period mention in the zones for
slgt chc to chc pops for now to handle this part. Timing of earlier
mentioned convection would be after 14z with a weakening trend
expected as low level jet temporarily weakens. Have went chc pops
into late morning to handle the upstream convection.
Departing/weakening convection could hamper any substantial heating
which would limit development until approach of the next wave late
this afternoon into evening.

Will hold onto likely pops this evening as low level jet ramps up
again and help get storms going. PWATs will increase to 2 inches or
greater making localized flooding an issue. Some of the same Hi-Res
models used for today shows coverage may not be as widespread as
previously thought and possibly confined more NW.

Finally...cold front will approach the region with at least
scattered showers and storms. Impacts from overnight convection and
subsequent heating will all be key factors in additional rain
chances. Went high chance pops for now with potential to need to
increase. Severe threat for today and tomorrow on the lower end but
still something to watch.


.LONG TERM...(Thursday Night through Tuesday)
Issued at 357 AM EDT Wed Aug 24 2016

Main shortwave energy will move well NE of the area with dry
conditions returning to the area for a few days before the next wave
ejects from the western states towards Sunday. Forecast will
continue riddled with slight chc to chance pops through the
remainder of the period as timing and impacts of several weak waves
move through the area on the periphery of upper level ridging over
the SE states. Entire upper air pattern remains somewhat suspect
into next week as impacts from a tropical system are unknown for the
area at this time.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 130 AM EDT Wed Aug 24 2016

Shrtwv across WI/IA accompanied by shra/ts expected to move east
across nrn IN today. Contd with just shra/vcsh in tafs as cloud
cover and encounter with upr ridge over ern U.S. may prevent sgfnt
destabilization in our area today. Low level moisture surge into
nrn IN should mainly impact sbn with mvfr cigs this morning while
cigs expected to lower to low vfr at fwa by this aftn.


.IWX Watches/Warnings/Advisories...


LONG TERM...Fisher

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