Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 250508
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
107 AM EDT Thu May 25 2017

.SYNOPSIS...
Issued at 306 PM EDT Wed May 24 2017

Showers and isolated thunderstorms are expected late this
afternoon into tonight. Some areas could see more than an inch of
rain, which could lead to flooding in already saturated
agricultural areas and along rivers. Thursday will feature cloudy
and cool conditions with lingering chances for rain showers. Lows
tonight will drop into the 50s, with highs tomorrow only
recovering into the 60s. Warmer temperatures and periodic low
chances for rain showers then Friday into the holiday weekend.

&&

.SHORT TERM...(This Evening through Thursday Night)
Issued at 306 PM EDT Wed May 24 2017

Continued expansion of showers/storms can be expected this
afternoon/early evening as forcing and deep moisture transport
(associated with shortwave and strong left exit jet support) lift
northeast into the Ohio Valley on the eastern fringe of an
unseasonably deep upper low dropping southeast through Missouri.
Locally heavy rainfall and better chances for thunderstorms will
be confined to our ne IN/nw OH counties where low level front
strengthens and nearly 1000 j/kg of SBCAPE resides. Lacking
shear/flow and meager lapse rates should preclude much of a severe
threat. The bigger concern will be the potential for localized
heavy rain/flooding, especially near the I-69 corridor.

The aforementioned shortwave/jet will help re-focus the main
circulation center to near Cincinnati by later tonight...then
gradually broadening east towards the Mid-Atlantic/Appalachians
Thursday into Thursday night. Developing TROWAL/deformation forcing
on the northern fringe will keep periods of rain in the forecast
into tonight. The strongest forcing will continue to focus into ne
IN/nw OH where highest PoPs/QPF were retained. Waning diurnal
instability should bring down the intensity in showers with little
in the way of embedded thunder anticipated mid evening into the
overnight. This will also lead to some constriction/narrowing of
the banding in our area with heavier rainfall more likely to focus
off the sse (more across east-central/se IN) near main vort
center.

Thursday will feature cool/cloudy northerly flow on the backside of
the increasingly stacked low. There may also be enough lingering
deformation/moisture and some diurnal heating to generate
additional showers mainly along/east of I-69 during the day.
Brief ridging through the column then brings fair wx Thursday
night into Friday morning.

&&

.LONG TERM...(Friday through Wednesday)
Issued at 306 PM EDT Wed May 24 2017

A brief transition to a flatter/more zonal flow pattern is expected
Friday into Saturday. A small scale/convectively aided perturbation
embedded in this flow (near a developing instability axis) will be
the main feature to watch for a period of rain/thunder later Friday
into early Saturday. The compact/low amplitude nature of this
feature is reeking havoc on models with confidence in timing/track
of associated precipitation below normal at this forecast range. As
a result will continue to accept blended chance PoPs. Mainly dry and
warmer otherwise.

The next/more pronounced shortwave in strengthening west-southwest
flow may bring another convective complex through the local area
Saturday night/early Sunday as an upper trough amplifies into the
Upper Midwest. Good surge of moisture/MUCAPE embedded in this
strengthening southwest flow may present a heavy rain/severe
weather threat as frontal boundary briefly lifts back in. Upper
troughing then becomes better established into the Great Lakes
region Sunday into next week resulting in cooler temperatures and
periodic chances for showers (mainly diurnally driven) as additional
shortwave energy pivots through.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 107 AM EDT Thu May 25 2017

Upr low cutoff ovr sw OH will open/weaken ewd through the mid atl
this aftn. Lingering mid lvl inverted troughing extending nwwd back
through srn MI will keep occasional shra going alg/within wrn bound
of mid lvl deformation zone invof KFWA. Hwvr dry entrainment ovr nw
IN and s/swwd wrapping trajectories shld keep most if not all shra
se of KSBN terminal. Otherwise ifr conditions will continue well
into this aftn before improving to mvfr as dry advection deepens on
stiff nwrly winds gusting to aoa 20kts by mid aftn.

&&

.MARINE...
Issued at 1150 AM EDT Wed May 24 2017

Waves of 3 to 4 feet will approach the shore at a 60 to 90 degree
angle by late this afternoon as they build to around 5 feet. Wave
periods will gradually lengthen to 5 to 6 seconds. These
conditions are supportive of strong rip current development within
sandbars, and strong structural currents near piers and
breakwalls. Furthermore, water temperatures are in the 50`s, which
can lead to hypothermia. People visiting the beaches of Lake
Michigan today should stay out of the water. Issued a small craft
advisory and a beach hazards statement for the dangerous
conditions.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Beach Hazards Statement through Thursday morning for INZ003.

MI...Beach Hazards Statement through Thursday morning for MIZ077.

OH...NONE.
LM...Small Craft Advisory until noon EDT Thursday for LMZ043-046.

&&

$$

SYNOPSIS...Steinwedel
SHORT TERM...Steinwedel
LONG TERM...Steinwedel
AVIATION...T
MARINE...MCD


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