Area Forecast Discussion
Issued by NWS Northern Indiana

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210
FXUS63 KIWX 210012
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
812 PM EDT WED JUL 20 2016

.SYNOPSIS...
Issued at 808 PM EDT Wed Jul 20 2016

Mainly dry conditions will persist into Thursday morning before a
warm front brings low chances for showers and storms into the
forecast Thursday afternoon and evening across northern Indiana
and southern Michigan. Lows tonight will range between the upper 60s
and lower 70s, with highs on Thursday into the lower 90s.
Afternoon heat indices will likely near 100 degrees. Hot and humid
conditions will continue Friday through the weekend with lows in
the 70s and highs in the upper 80s to mid 90s. Heat indices each
afternoon may exceed 100 degrees. There is also a chance for
thunderstorms through the period, best chances Friday morning and
again Sunday into Sunday Night.

&&

.SHORT TERM...(This Evening through Friday)
Issued at 330 PM EDT Wed Jul 20 2016

Heat/Humidity builds and low shower/storm chances Thursday-Friday...

Very humid/hot airmass over the Central US under expansive upper
ridge will continue to slowly fold east into the local area tonight
into Thursday with afternoon heat indices Thursday anticipated to
approach 100F into our IN/sw MI zones. Associated Instability
gradient/weak warm front has been fairly active across the
Mid/Upper MS Valleys the last couple of days and will need to be
monitored as it mixes into our IN/MI counties overnight into
Thursday. However, expect bulk of convection tonight to re-focus
more into the western/northern Great Lakes on nose of moisture
channel/LLJ. This activity will then need to be watched into
Thursday afternoon as boundary layer destabilizes and a
outflow/leftover boundary tries to spark sct convection into our
IN/MI counties. Probabilities of seeing any
redevelopment/convection this far south remains very low however
given northward bypass of any flow/forcing and capping concerns as
upper ridge becomes better established locally.

A low amplitude/convectively aided shortwave is then expected to
propagate ese through the Northern/Central Great Lakes later
Thursday Night into Friday briefly breaking down ridge. This
feature will bring slightly better chances for showers/storms
during this time as associated convective complex could hold
together south into a very moist environment early Friday morning
(best chances north)...with iso-sct redevelopment possible along
composite outflow Friday afternoon amid extreme instability (best
chances across ne IN/nw OH in the afternoon). If any storms can
develop they would pose an isolated wind/heavy rain threat at best
given lacking deep layer shear/flow. Otherwise, dangerous
heat/humidity the larger story on Friday with dewpoints expected
to be in the 70s and sfc ambient temps into the low-mid 90s by
afternoon. How warm we get/how extreme heat indices area will be
dependent on cloud debris which remains a bit uncertain at this
fcst range.

&&

.LONG TERM...(Friday Night through Wednesday)
Issued at 330 PM EDT Wed Jul 20 2016

Hot/humid weekend...then cooler/less humid/dry into early next
week...

Heights rebound with deeper moisture/weakening frontal boundary
likely stalling over or just south of the area Friday Night through
early Sunday will continue to support humid conditions and low
chances for showers/storms. The next low amplitude shortwave to
crest/flatten Central US upper ridge will drag a frontal system and
renewed theta-e surge through around Sunday/Sunday Night. This looks
to be the best opportunity for rain/storms (best chances in the
afternoon/evening) given weak height falls and better flow. Much
drier/less humid air then spills in for the first half of next week
post-frontal.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 808 PM EDT Wed Jul 20 2016

VFR met conditions should prevail through the period. Low
potential for shallow/patchy fog to provide minor vsby obscuration
at KFWA near daybreak. And also a very low chance for isolated
TSRA across northern Indiana/east of I69 Thu afternoon, however
the low probability/conditional nature of such suggests forgoing
even a VCTS mention at this time.

&&

.IWX Watches/Warnings/Advisories...
IN...Heat Advisory from 2 PM Thursday to 8 PM EDT Friday for INZ006-
     007-009.

     Heat Advisory from 2 PM EDT /1 PM CDT/ Thursday to 8 PM EDT /7
     PM CDT/ Saturday for INZ003>005-008-012>018-020-022>027-
     032>034.

MI...Heat Advisory from 2 PM Thursday to 8 PM EDT Friday for
     MIZ077>081.

OH...Heat Advisory from 2 PM Thursday to 8 PM EDT Friday for OHZ001-
     002-004-015.

LM...NONE.
&&

$$

SYNOPSIS...Murphy
SHORT TERM...Steinwedel
LONG TERM...Steinwedel
AVIATION...Murphy


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