Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 171939
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
339 PM EDT Thu Aug 17 2017

.UPDATE...
The SYNOPSIS, NEAR TERM, SHORT TERM, and LONG TERM sections have been
updated below.

&&

.SYNOPSIS...
Issued at 339 PM EDT Thu Aug 17 2017

Low chances for rain will linger into this evening as a front exits
the area. After a dry day Friday, an upper system will bring more
chances for rain Friday night and Saturday. Look for warm and
increasingly humid conditions Sunday and Monday, before a cold front
brings cooler conditions for mid to late week along with some rain
chances Tuesday and Wednesday.

&&

.NEAR TERM.../Rest of This Afternoon and Tonight/
Issued at 339 PM EDT Thu Aug 17 2017

Pre-frontal trough has moved east of central Indiana taking most of
the convection with it. However, the front remains well west of the
area. With higher dewpoints remaining in the area and additional
heating expected (rebuilding the instability), still believe some
convection may refire this afternoon. However with most support with
the pre-frontal trough to the east, don`t believe there will be much
in the way of coverage. Will keep PoPs low.

Based on the timing of the front, there could still be a few storms
this evening across the southeast 2/3 of the area. Will keep low
PoPs going through the evening there.

Drier air will move in behind the front overnight providing dry
conditions. The model blend looks good for low temperatures
overnight.

Confidence is low to medium in rain chances into this evening, but
medium to high in dry conditions overnight.

&&

.SHORT TERM.../Friday through Sunday/
Issued at 339 PM EDT Thu Aug 17 2017

Models are close enough that the model blend initialization was
accepted for most items.

Central Indiana will be in between systems on Friday, so will
continue with a dry forecast.

Friday night into Saturday an upper trough will move through the
area. An upper jet will provide additional forcing. The timing of
the system isn`t great for instability to aid in convection though.
Will keep PoPs in chance category or lower and time the highest PoPs
overnight Friday night and during the first half of the day
Saturday, based on expected timing of the system.

High pressure will then build in and keep the weather dry across the
area Saturday night into Sunday.

The model blend temperatures look good given expected conditions.

Confidence is medium in rain chances and timing through the short
term.

&&

.LONG TERM.../Sunday Night Through Thursday/
Issued at 339 PM EDT Thu Aug 17 2017

Models are close enough that the model blend initialization
was accepted for most items.

A flat upper ridge will nudge into the area early in the period and
should provide dry but very warm conditions through Monday evening.
With some models generating convection well to the west of the area
Monday, will have to see if any of the high clouds make it into the
area during eclipse time. At the moment though it still appears that
coverage of opaque cloud cover will be low, but of course that far
out confidence is still on the lower end of the spectrum.

An upper trough will set up across the eastern USA during the latter
part of the long term, and this will allow a cold front to move
through. Will have chances for rain Tuesday and Wednesday, but
Thursday will be dry and cooler with high pressure moving in.

&&

.AVIATION (Discussion for the 171800Z TAF Issuance)...
Issued at 102 PM EDT Thu Aug 17 2017

VFR conditions expected for most of the period. Lower conditions
possible in convection this afternoon.

Main lines of convection has passed the TAF sites, but additional
convection may develop this afternoon with cold front still to the
west. Based on latest hi res model data, have only put VCTS in at
KBMG, with just VCSH at most other sites. However, can`t rule out
thunder at any site during the afternoon.

Some MVFR ceilings may work into mainly the northern sites this
afternoon based on upstream conditions, but at the moment confidence
is not high enough to put in the TAF.

Winds will be gusty this afternoon. Tonight/Friday drier air will
work in and keep conditions VFR.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM...50
AVIATION...50



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