Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 280517

Area Forecast Discussion
National Weather Service Northern Indiana
117 AM EDT Mon May 28 2018

Issued at 740 PM EDT Sun May 27 2018

Much above normal temperatures will continue into Monday and
Tuesday. High temperatures on Monday afternoon will reach into
the lower to mid 90s, and into the lower 90s for Tuesday
afternoon. Mainly dry conditions are expected Monday and Tuesday,
but rain and thunderstorm chances will increase on Wednesday as
the remnants of tropical storm Alberto lift northward across the
Ohio Valley and southern Great Lakes. Highs by Wednesday will be
limited to the upper 70s and lower 80s due to the increased cloud
cover and precipitation.


.SHORT TERM...(This Evening through Tuesday)
Issued at 156 PM EDT Sun May 27 2018

Model initialization matching up well with 12Z ROABs in depicting
500mb ridging over the plains and 850mb thermal ridge. Mid-level
short wave now east of the area will allow for plains ridging to
expand eastward into our region. 850mb temps around 20C for
Memorial Day will have highs in the low to mid 90s once again.
Weaker gradient over the area Monday compared to today so agree
with previous discussion that lake breeze more likely to develop
and keep highs cooler near the lakeshore. Upper ridge holds in
place over the great lakes through Tuesday while remnants of
Alberto moves up into the TN valley. Also in play is Canadian high
pressure moving into the southern tip of Hudson Bay that will
bring a back door type cold front toward the northern CWA. This
may trigger a shower or thunderstorm by Tuesday afternoon with
over 2000J/kg of CAPE and no cap. Still expect to reach 90F again
but also expecting increase in high clouds in advance of Alberto
which should limit mid 90s potential in southern CWA. Dewpoints
currently in the low to mid 60s and not expected to change much
over the forecast period so overnight lows wont be too
uncomfortable...generally mid 60s.


.LONG TERM...(Tuesday Night through Sunday)
Issued at 156 PM EDT Sun May 27 2018

Forecast period begins with extended period of rain/thunderstorm
chances as the remnants of Alberto impact the region. Closed upper
low over the intermountain west is expected to lift northeast
into the northern plains by Tuesday night as Alberto moves up into
the southern great lakes. Models in decent agreement in phasing
these two features into the northern stream flow but vary on
timing and northward extent of lifting this through the great
lakes and into southern Canada. ECMWF taking it up into southern
Quebec Thursday night/Friday timeframe while GFS only takes it to
southern Ontario border. Either way...this leaves a 2 day window
for our area to be impacted by a very precip efficient system as
ensemble means have PW values approaching 2 inches Wednesday.
While the exact track of Alberto remnants may still change over
the next couple of days...current model trends suggest at least 1
inch of precip for most of the CWA with 1.5-2.0 inches possible
over western half. With clouds/precip expected to move in Tuesday
night...diurnal destablization will be limited on Wednesday...but
can still expect to see some embedded convective elements which
will have potential for 2in/hr precip rates. End of the forecast
period looking mainly dry for next weekend as ridging builds back
into the region but with more seasonable temperatures.


.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 110 AM EDT Mon May 28 2018

Light winds and VFR conditions to prevail once again. May be some
higher based cu during the afternoon but no precip is expected.





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