Area Forecast Discussion
Issued by NWS Northern Indiana

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KIWX 190541

Area Forecast Discussion
National Weather Service Northern Indiana
141 AM EDT Mon Aug 19 2019

Issued at 627 PM EDT Sun Aug 18 2019

Scattered thunderstorms will role east through the area into the
evening. An isolated strong to severe thunderstorm will be
possible, best chances along and southeast of US 24.
Periodic low chances for showers and thunderstorms and warm
temperatures will persist into Monday and Tuesday, followed by
cool and dry conditions Wednesday through Saturday.


.SHORT TERM...(This Evening through Monday)
Issued at 233 PM EDT Sun Aug 18 2019

MLCAPE has increased to near 2000 j/kg and CIN has largely eroded
along and in advance of a composite outflow boundary draped near
the US 24 corridor. Coverage is rather isolated as of 1815z but
expected to increase mid-late afternoon as a convectively aided
impulse approaches from the Mid MS Valley. Most of this activity
is expected along/southeast of US 24, though additional
development possible on the edge of stable bubble to the north as
boundary layer attempts to recover with outflows in the vicinity.
Effective shear values in the 25-30 kt range and moderate
instability may be enough to support a few strong to severe storms
with wind the primary threat.

Chances for showers/storms diminish later this evening into
Monday morning behind these series of shortwaves, though a few
leftover showers not out of the question as the main synoptic cold
front and pooled moisture drop in from the northwest. Fog and
stratus may be able to fill in otherwise later tonight given ample
low level moisture. This remnant moisture and diurnal heating may
contribute to iso-sct convection by Monday afternoon near the
weak front. Storms should stay below severe limits and mainly
confined to southern/eastern zones.


.LONG TERM...(Monday Night through Sunday)
Issued at 233 PM EDT Sun Aug 18 2019

The next chance for a round of convection will come later Tuesday
into Tuesday night as the next convective complex and associated
theta-e surge rides the northeast fringe of a persistent south-
central CONUS upper ridge. This convection will pose a severe
threat, though higher probabilities appear to be west of the IWX
CWA at this time. Quiet weather and lower humidity then becomes
the story mid-late week as negative height anomaly dropping into
southeast Canada finally forces active frontal zone off to the


.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1244 AM EDT Mon Aug 19 2019

Patchy MVFR to LIFR ceilings developing across north central
Indiana for the start of the 06Z TAF cycle. While both terminals
are starting off at VFR, a degradation in flight category is
expected for a sizable portion of the first half of this TAF
cycle. The above mentioned area of stratus should expand eastwards
with time as high clouds clear. This will likely result in
ceilings dropping to IFR and possibly LIFR during the first 6
hours. For KSBN, light winds and clear skies will likely allow
ground fog to expand eastwards from Lake Michigan. Have inserted
a drop to MVFR with brief period of slightly lower. The low
stratus and fog affecting the terminals should see a gradual
increase to MVFR around the 12Z hour as a weak cold front slides
southwards into the area. While this front would bring a wind
shift, wind speeds are expected to remain less than 5kt. Moving
towards the afternoon, there is a slight chance for scattered
showers and thunderstorms as flight categories return to VFR. For
this issuance, a PROB30 group was included in from KFWA given the
proximity to the residual front. KSBN was not included as chances
are too low at this point.




SHORT TERM...Steinwedel
LONG TERM...Steinwedel

Visit us at

Follow us on Facebook...Twitter...and YouTube at: is the U.S. government's official web portal to all federal, state and local government web resources and services.