Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 220803

Area Forecast Discussion
National Weather Service Northern Indiana
403 AM EDT FRI JUL 22 2016

Issued at 354 AM EDT Fri Jul 22 2016

A strong high pressure system centered off the mid Atlantic coast
will continue to cause a southerly flow of hot and humid
air across our area today. A weak cold front will move south
across lower Michigan today and into northern portions of Indiana
and Ohio tonight, possibly causing scattered thunderstorms in our
area. Highs today will be in the lower 90s, which combined with
the high humidity, will result in heat index readings over 100
across much of the area. Lows tonight are expected to be in the
upper 60s and lower 70s.


.SHORT TERM...(Today and Tonight)
Issued at 354 AM EDT Fri Jul 22 2016

Outflow boundary emanating from mcs dropping into central il/in this
morning was movg se across our cwa with so far no convective
response, as airmass apparently still stabilized from aftn/eve
convection. Convective debris cirrostratus canopy should gradually
diminish this morning allowing airmass to become very unstable,
although weakly capped, this aftn. Wk sfc boundary associated with
shrtwv movg ese across srn ontario/swrn quebec will drop south into
this unstable airmass this aftn, psbly triggering sct tstms and with
wk synoptic flow/very unstable airmass in place, suspect this
activity if it does occur will linger into tonight along frontal
convergence zone and other outflow boundaries. Given the very
unstable airmass with wk deep layer shear in place, an isolated
severe storm is psbl. Temps should be a few degrees warmer than yday
with more aftn sunshine. This combined with a little higher dwpts
should result in heat index readings above our advisory criteria
(around 100). No sgfnt relief from heat tonight as abundant low
level moisture holds temps in the 70s.


.LONG TERM...(Saturday through Thursday)
Issued at 354 AM EDT Fri Jul 22 2016

The weak frontal boundary is expected to stall out over our cwa
Saturday and then lift n-ne Sat ngt as a seasonably strong shrtwv
and associated sfc low/cdfnt move east across srn sask/manitoba and
the daks. Airmass will remain very moist/unstable but bufr soundings
suggest a little stronger capping around 5kft so kept pops low. A
little drier air north of the stalled frontal boundary should allow
for heat index readings to be blo advisory criteria across nrn
portion of the cwa with heat index around 100 contg to the south.

Tstms chances increase a bit Sunday/Sunday night as plains
shrtwv/cdfnt moves into the upr grtlks. Cdfnt should still be movg
across the sern portion of the cwa Monday continuing the threat of
tstms in that area. By Tuesday, post-frontal high pressure
expected to build in providing a couple of days with lower
humidity and slightly cooler temps.


.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 129 AM EDT Fri Jul 22 2016

Low confidence tafs for the upcoming period as models have
absolutely no consensus on what may unfold through tonight.

Initial focus on outflow boundary moving southeast already clear
of ksbn and likely to make an attempt to reach kfwa. Despite a
weakening stratiform rain field in its wake...enough elevated
instability exists to allow for sporadic development of showers
and storms along this boundary. Will hold onto a period of showers
and introduce vcts at kfwa to handle the threat. Locally gusty
winds have been occurring in the wake of the convective system
over lk michigan and near the shoreline with gusts of 30 to 35
kts. These could work in land and affect ksbn but for now will
leave out of tafs.

Focus then shifts to convective potential this afternoon with
what should be rather unstable conditions in place for a frontal
boundary (assuming skies clear out today) to interact with as it
drops south into the area. At this point...confidence low enough
to just maintain vcts after 18z with any threat ending around 00z
as loss of heating diminishes any convection.


.IWX Watches/Warnings/Advisories...
IN...Heat Advisory until 8 PM EDT /7 PM CDT/ Saturday for INZ003>009-

MI...Heat Advisory until 8 PM EDT this evening for MIZ077>081.

OH...Heat Advisory until 8 PM EDT Saturday for OHZ001-002-004-005-015-




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