Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 242313

Area Forecast Discussion
National Weather Service Indianapolis IN
713 PM EDT SAT SEP 24 2016

The AVIATION Section has been updated below.


Issued at 214 PM EDT Sat Sep 24 2016

High pressure over the Great Lakes will continue to provide dry
weather tonight and Sunday across Central Indiana. A cold front
over the Central Plains will push into Central Indiana on Late
Sunday night and early on Monday...bringing chances for rain to
the state.

Cooler...more seasonable temperatures are expected to arrive on
Monday night and last into the middle of the next work week as
another High pressure system arrives.


.NEAR TERM /Tonight/...

Issued at 214 PM EDT Sat Sep 24 2016

Water Vapor Imagery this afternoon shows a strong Ridge of High
pressure in place across the Mississippi River Valley. Visible
Pictures show lingering clouds across Northern Indiana dissipating
quickly withing daytime heating and ongoing mixing. Surface analysis
continue to show High Pressure in place across the Great Lakes with
NE flow across Indiana.

The strong protective Ridge and High pressure in place at the
surface will continue to provide dry weather for Central Indiana
tonight. Forecast soundings remain rather dry...however time heights
showing some lingering lower level moisture and dew point
depressions are expected to fall to 1f or less. With a decent
pressure gradient in place...will trend once again toward a stratus
deck forming overnight and patchy fog cannot be ruled out.
A blend on low temps will work nicely.


.SHORT TERM /Sunday through Tuesday/...

Issued at 214 PM EDT Sat Sep 24 2016

NAM and GFS suggest the ridge of High pressure and associated
surface High will begin to drift east on Sunday. The protection of
the high will last through the day to provide one more day of
summer like heat along with light southerly winds. Forecast
soundings remain dry...thus partly cloudy skies will be expected.

Big weather change arrives on Sunday Night and Monday as GFS and
NAM suggest the strong trough aloft over the upper midwest will
drop southeast onto the Ohio Valley. An associated cold front
will accompany the system...providing ample dynamics. The 305K GFS
isentropic surface shows some upglide with a very moist air mass
with specific humidities over 9 g/kg. Time heights and forecast
soundings also hint at deep saturation...mainly aft 06z. Thus will
trend toward a dry evening on sunday...but ramp pops up on late
sunday night and early monday.

Cold front and associated moisture will be moving through Central
Indiana near 12Z...but exits quickly by 18Z and models suggest the
cold front and best moisture pushes well to the southeast by
then. forecast soundings show excellent subsidence and drying by
18z. Thus Will try to contain any pops on Monday to mainly the
morning hours. Again will ramp pops higher than
MAVMOs...particularly across the SE where timing is most
favorable. Given the expected cold air advection in the wake of
the front will trend highs on monday closer to the 3 hourly values
and trend toward wetbulbs on Sunday night lows.

HIgh pressure and strong subsidence look to remain in place into
Tuesday with forecast soundings showing a dry column and
unreachable convective temperatures. Thus will trend toward a
partly cloudy sky and a blend on temps here.


.LONG TERM (Tuesday Night through Saturday)...
Issued at 138 PM EDT Sat Sep 24 2016

A departing large upper low will give way to broad surface high
pressure during the long term period. This will produce a seasonably
mild, dry period throughout the long term portion of the forecast.

Initialization handled this well and few changes were required.


.AVIATION /Discussion for 250000z TAF issuance/...

Issued at 707 PM EDT Sat Sep 24 2016

VFR conditions for some of the night will give way to MVFR and
perhaps IFR conditions at some sights by early morning. Time
heights and guidance indicate potential again for some fog and/or
low ceilings. Continued with a mention of a scattered deck at 800
ft to point to the ceiling potential. Also went with MVFR fog
developing, and included a tempo for IFR for at KBMG. Not high
enough confidence at this time to go lower or similar to what
happened early this morning, with much of the area seeing good
sunshine from midday on to dry out some of the available moisture.
Winds should be light but not calm and out of the northeast to
east tonight.


.IND Watches/Warnings/Advisories...


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