Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 220937

Area Forecast Discussion
National Weather Service Northern Indiana
537 AM EDT Sat Jul 22 2017

Issued at 530 AM EDT SAT Jul 22 2017

Showers and thunderstorms will gradually diminish this morning.
Localized flooding is possible in areas that received over an inch
of rain last night. There will be a lingering chance for
thunderstorms this afternoon and evening...especially south of the
highway 24 corridor. Another system will move through the region
Sunday afternoon and evening with chances for thunderstorms again
during this period. Drier and cooler air will then prevail for the
first part of the upcoming week.


.SHORT TERM...(Today and Tonight)
Issued at 530 AM EDT Sat Jul 22 2017

Several mesoscale convective complexes moving through the region
this morning. First MCV rotating through eastern area and severe
threat this morning ending as this feature exits. Strong warm air
advection and low level jet to our west has fueled a second MCS over
eastern IA and northern IL and this making its way into NW Indiana
early this morning. Primary concern will be heavy rain threat rest
of this morning with PWATs still over 2 inches. Expect this complex
to begin weakening as it translates through the area this morning as
LLJ weakens and moisture convergence diminishes.

Focus then shifts to afternoon convection and severe chances. Fully
expect composite outflow from this morning convection to be well
south of the area today and stable bubble over most of CWA. Clouds
will linger this morning and possibly into this afternoon once again
limiting heating and keeping thermal gradient to our south. High dew
point air still in place and even with clouds could see CAPE of at
least 1500-2000 J/KG develop. However lack of focus and with
boundary south of area along with local CIN thinking best chances
for any development will be in our far south. Last several CAMs runs
tend to agree and latest HRRR develops storms along our southern
border. Will trend afternoon pops in this direction with highest in
our far south. Isolated severe will be possible where storms do
develop and again primarily focused in our far southern counties.
Evening storms should then push south of the area with approach of
first synoptic frontal boundary and drying overnight.


.LONG TERM...(Sunday through Friday)
Issued at 530 AM EDT Sat Jul 22 2017

Short wave and associated secondary cold front to swing south Sunday
into Sunday evening. Models continue to indicate possible convection
with these features as low level moisture lingers and CAPE values
increase to over 2000 j/KG. Deep layer shear also increases to over
30 knots so isolated severe not out of question and thus the day 2
slight risk. Once this wave passes should finally see drier and
cooler air work in for Monday and first half of upcoming week.

Another short wave in west northwest flow looks to arrive mid week
with another sagging surface front. This will bring chances for
showers and storms back to the area for latter half of the week.
Basically accepted blends for later periods with focus this morning
on short term weather.


.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 143 AM EDT Sat Jul 22 2017

Ongoing convection will continue through the night with storms
lined up back through IL. KSBN to likely see stratiform rain with
embedded thunder for a few more hours. KFWA to see a storm next 1
to 2 hours followed by a brief break before next batch in
northwest Indiana rotates east. Tried to add this timing to tafs.
Expecting outflow from early morning storms to push well south of
terminals and likely cut tsra potential on Saturday. Chances look
too small at this time for inclusion in point forecast and will
evaluate further overnight.




SHORT TERM...Lashley
LONG TERM...Lashley

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