Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 171754

Area Forecast Discussion
National Weather Service Northern Indiana
154 PM EDT WED AUG 17 2016

Issued at 137 PM EDT Wed Aug 17 2016

Showers and thunderstorms are possible this afternoon and evening as
a weak disturbance moves through the area. There may be a few
stronger storms with gusty winds and small hail, but widespread
severe weather is not expected. Flooding is ongoing in parts of
northwestern Indiana and southwestern Lower Michigan due to recent
heavy rains. Monitor our webpage for the latest on this situation.


.SHORT TERM...(Today and Tonight)
Issued at 422 AM EDT Wed Aug 17 2016

The earlier areal flood warning was extended due to ongoing flooding
from South Bend to north of Plymouth. Will continue the flood
warning at the time. An upper level trof should move into the area
this afternoon and should help trigger scattered thunderstorms.
However, higher rainfall amounts should be localized and should have
little if any effect on the current flood situation.

Otherwise, patchy dense fog had developed where skies had cleared
over northwest Indiana into southern Lower Michigan. The fog should
mix out shortly after daybreak.


.LONG TERM...(Thursday through Tuesday)
Issued at 422 AM EDT Wed Aug 17 2016

An upper level short wave trof will amplify and move across North
America this weekend. The ongoing timing of this system appears on
track with subsequently the best chances for storms Saturday through
Sunday. Precipitable water values should approach 2.0 inches with
max CAPEs in the 1500 to 2000 J/Kg range per GFS BUFKIT. Conditions
appear marginal for severe storms given good upper level support
combined with marginal instability and marginal low level shear.
Otherwise, Thursday and Friday as well as Monday and Tuesday should
be mainly dry, although an afternoon storm is possible Thursday.
Temperatures should climb a little above normal in the mid 80s
Friday, but cooler and less humid weather early next week with highs
in the 70s.


.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 137 PM EDT Wed Aug 17 2016

Afternoon instability combined with an approaching shortwave aloft
has led to cumulus development across much of the area, with
primarily VFR conditions. The shortwave has managed to generate a
few showers and thunderstorms, particularly to the north of the
TAF sites in Lower Michigan, however-as of 18z development over
Indiana has been non-existent. Models are still in disagreement
over shower/storm development at this point-but it`s not out of
the question. For now left it out of the TAF given low
confidence, but will continue to closely monitor. Otherwise, the
focus turns to fog development again tonight. Winds will again be
light with lingering low level moisture-so thinking things will be
similar to last night. Guidance is not as pessimistic on ceiling
heights, but they bring visibilities down to around 1 mile or
less between 8-12Z. For now kept things IFR, with visibilities
down to 2 miles at KSBN where conditions look most favorable and 3
miles at FWA. LIFR conditions are certainly in the realm of
possibilities but will leave out until the next TAF issuance where
we can re- evaluate.


.IWX Watches/Warnings/Advisories...


SHORT TERM...Skipper
LONG TERM...Skipper

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