Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 200400

Area Forecast Discussion
National Weather Service Indianapolis IN
1200 AM EDT Wed Sep 20 2017

Aviation Section has been updated below.


Issued at 235 PM EDT Tue Sep 19 2017

A weak surface and upper trough will exit Indiana this evening and
the few remaining showers and storms will dissipate around dusk.
Strong upper ridging will build in its wake and provide a warm and
mostly dry period from Wednesday into early next week. The front
currently in the northern Plains will run into this ridge Thursday
and bring a low chance for showers here but otherwise dry weather
will be the rule. With upper heights quite high, temperatures above
normal will prevail.

Model solutions were in fairly good agreement and followed.


.NEAR TERM /Rest of Tonight/...
Issued at 832 PM EDT Tue Sep 19 2017

An upper and surface trough of low pressure over western Ohio
has produced an area of thunderstorms over east central sections
and this will continue a few hours into the evening before moving
on to the east.   Only other change was to add patchy fog most areas
late tonight given a fairly moist ground combined with some clearing
overnight.   Low temperatures will be in the lower to middle 60s and
only minor tweaks made to the rest of the near term period.


.SHORT TERM /Wednesday into Friday/...

Issued at 235 PM EDT Tue Sep 19 2017

Upper level ridging will dominate this period. With warming
subsidence occurring, the above normal temperature regime will
continue. Storms along a cold front today will approach Indiana
Thursday. Overall, the ridge should prevail and keep us dry but with
some uncertainty, will keep a low chance of precipitation with this
feature as it moves across our area early Thursday. Once this threat
leaves, no chance for rain is expected again before next week.

Guidance temperature blends, above normal, appeared reasonable and
were used.


.LONG TERM /Friday through Monday/...
Issued at 228 AM EDT Tue Sep 19 2017

ECMWF suggests dry weather with above normal temperatures through
this period. ECWMF shows strong ridging in place aloft across the
eastern half of the country. The strong ridge looks to keep Indiana
protected from passing dynamics...keeping them well northwest of
Indiana. Meanwhile at the surface strong subsidence beneath the
ridge results in surface High pressure across the eastern Great
Lakes that keep as dry Easterly flow across Indiana through the
weekend. thus have trended toward a dry forecast. With little to no
change in air mass...have trended highs at or above the forecast
builder blend as warm air reigns supreme under the ridge.


.AVIATION.../Discussion for 06Z TAF Issuance/...
Issued at 1230 AM EDT Wed Sep 20 2017

Ridge of high pressure over Indiana will move on to the east
as an area of low pressure over the central plains moves towards
the upper midwest and great lakes.  This will be followed by a
2nd low pressure system moving into the southern plains Wednesday

Fog will be the main concern...especially north where temperature
dewpoint spreads already near zero.   Expect KLAF to drop to IFR
as well as KBMG.   Meanwhile KIND and KHUF may see a period of
MVFR fog towards daybreak.  All fog will burn off by mid morning
and VFR after that with Few-Sct CU.

Winds will be light overnight and south 5 to 8 knots after mid
morning Wednesday.




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