Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 211836

Area Forecast Discussion
National Weather Service Northern Indiana
236 PM EDT Wed Jun 21 2017

Issued at 211 PM EDT Wed Jun 21 2017

High clouds will increase during the evening and overnight as a
warm front approaches. Isolated showers and thunder are possible
late tonight into early Thursday morning. Increasing moisture and
heat on Thursday will lead to a better chance of thunderstorms
Thursday evening and into the early morning Friday. Late
Thursday...there is a slight chance of severe thunderstorms with
the most favored areas along and north of the Indiana- Michigan


.SHORT TERM...(This Evening through Thursday)
Issued at 211 PM EDT Wed Jun 21 2017

All of the high resolution short term models are suggesting
suppression of convection through much of the evening and
overnight. Weak subsidence and downslope flow persists over our
area until the warm intrusion starts into the region late
tonight/early Thursday morning. Additionally, models suggest that
the deformation axis between TS Cindy and the approaching
shortwave trof will continue to diminsh moisture advection and
further suppress convection in the near term.

Heat indices on Thursday expected to rise into the lower 90s. The
challenge with this is the amount of cloud cover. Expect that we
will see more high level clouds overspreading the region as TS
Cindy continues moving north.


.LONG TERM...(Thursday Night through Wednesday)
Issued at 211 PM EDT Wed Jun 21 2017

Warm frontal passage and destabilization during the day Thursday
sets the stage for more organized convection late Thursday into
Friday morning. Similar to last few events this will be late,
beyond the peak insolation period, so expect the coverage and
intensity to be somewhat limited. Will also have to monitor
closely the cloud cover, as that will have an impact on the BL
temperatures and instability. With sufficient moisture, there is a
good chance of locally heavy rainfall and as the cooler air
settles in the wake of deeper convection could see a prolonged
period of steady rainfall persisting through Friday.

Cooler air settles across the region for the weekend and through
the mid week. Temperatures will be 5 to 10 degrees below normal.
With broad scale westerly flow and trof over eastern NA,
reinforcing cool air and occasional short waves cannot be ruled
out. While PoP is low through the period, have low confidence
that the entire period will be rain-free.


.AVIATION...(For the 12Z TAFS through 12Z Thursday Morning)
Issued at 647 AM EDT Wed Jun 21 2017

VFR conditions are expected throughout the TAF period. Low level
wind shear is a possibility tonight at KSBN, as a warm front surges
northward through the area and a LLJ develops over WI/IL/Far NW IN.
There are some low chances for showers and thunderstorms later
tonight along the warm front-however most models show precipitation
developing to the north and east of the TAF Sites. Given the low
confidence, left it out of the TAF for now. Winds will veer around
to the south-southwest through Thursday, and begin gusting into the
upper teens and low to mid 20s. Better chances for storms will be
late Thursday afternoon and evening.





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