Area Forecast Discussion
Issued by NWS Northern Indiana

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503
FXUS63 KIWX 301743
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
143 PM EDT Thu Mar 30 2017

.SYNOPSIS...
Issued at 145 PM EDT Thu Mar 30 2017

Showers and thunderstorms are expected in the area this afternoon
and tonight as a low pressure system approaches from the Southern
Plains. There is a risk of severe storms, especially across
along and south of US-24 this afternoon and this evening. Showers
will taper off from west to east Friday as the low departs. High
pressure will build into the Midwest Saturday providing fair
weather.

&&

.UPDATE...
Issued at 1122 AM EDT Thu Mar 30 2017

Forecast for this aftn/eve on track with some concern for
isolated severe storms mainly southeast of US 24 between 20-02z as
sfc warm front draped across southern IL-southwest IN mixes north
to near our far southern zones late aftn/eve. 0-3km helicity of
300-500 m2/s2 and deep layer shear in excess of 40 knots favorable
near this boundary by this time, though sfc/mixed layer buoyancy
remains uncertain with latest NAM CAPE progs likely a little too
aggressive with MLCAPE`s in excess of 1000 j/kg. Favor the more
stable HRRR progs given extensive cloud cover and lower sfc
dewpoints (mid-upper 50s) when compared to the NAM. As a result
expect this to be a rather messy convective event southeast of US
24. With that said cannot rule out an isolated severe storm with
brief tornado, small hail, and damaging winds the primary threats
if any low centroid/line segments organize. Cool and occasionally
wet with embedded thunder elsewhere.

&&

.SHORT TERM...(Today through Friday)
Issued at 453 AM EDT Thu Mar 30 2017

A vigorous upper level low was centered over eastern Kansas early
this morning. This system will move east and track north of the
Ohio Valley Friday. Several factors appear to be coming together
for the potential for severe storms over the forecast area today
and early tonight. A warm front will move north today and should
be close to Highway 30 by late afternoon. A cool east flow north
of the front off Lake Erie will accentuate the front. Increasing
instability combined with increasing low level shear will enhance
the chances for strong to severe storms including large hail,
damaging winds and isolated tornadoes along and south of the
front. The best chances for severe storms is from mid afternoon
through this evening. Precipitable water values are still expected
to approach climatological maxes of 1.25 for this time of year.
Rainfall amounts by the time rain ends Friday should range
between 0.75 inches over northwest Ohio to 1.25 inches over
northwest Indiana. Lingering rain will diminish Friday as the low
moves east and high pressure builds across the area.

&&

.LONG TERM...(Friday night through Wednesday)
Issued at 453 AM EDT Thu Mar 30 2017

Two more rounds of rain are on the horizon as more upper level
systems move across the area next week. Rain is expected to
develop by late Sunday and continue into Monday with the arrival
of next system. After a break Tuesday, more rain is likely
Wednesday. Thermal profiles favor all rain.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 140 PM EDT Thu Mar 30 2017

Low pressure will continue to approach the area, and after a brief
window of no rain, showers and thunderstorms will come back in for
this afternoon. Showers and thunderstorms have the capability of
reducing conditions into MVFR and possibly IFR within heavier rain
and lower LCLs. The warm front will slowly push from south to
north through the area by early overnight, thus the greater chance
for severe weather is at FWA where the residence time for heating
and accumulation of instability will be greater. The main impacts
will be gusty wind and hail. Moisture will remain around the
region overnight with the low pressure system still nearby and,
with the weaker winds, there could be areas of fog that form with
a greater chance at SBN than FWA. Stronger winds begin to come
back in right around daybreak tomorrow as the low pressure system
vacates the region pushing the moisture out early, though some low
stratus could still remain.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Small Craft Advisory until 4 PM EDT this afternoon for LMZ043-
     046.

&&

$$

UPDATE...Steinwedel
SYNOPSIS...Roller
SHORT TERM...Skipper
LONG TERM...Skipper
AVIATION...Roller


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