Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 250704
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
304 AM EDT SUN SEP 25 2016

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

&&

.SYNOPSIS...
Issued at 304 AM EDT Sun Sep 25 2016

A cold front will move through the area tonight into early Monday
bringing showers and a few thunderstorms to the area. An upper low
could bring a few showers to northern areas mid week. Dry conditions
will then prevail. After one more warm day today, cooler and more
seasonable readings will continue into next weekend.

&&

.NEAR TERM.../Today/
Issued at 304 AM EDT Sun Sep 25 2016

A cold front will approach the area today. Until later in the day,
high pressure should remain in control with just an increase in
clouds.

Some models bring in rain before 00Z to the western forecast area
ahead of the front. The Hi Res Rapid Refresh has convection into the
area by 19Z. This seems overdone given what little forcing will be
available before the front arrives.

However, the GFS and Canadian bring in rain before 00Z. Although
less weight is given to the GFS since it typically overdoes QPF
coverage, the SREF also hints at this possibility. Given the above,
and after looking at neighboring office`s input, have decided to add
some slight chance PoPs to the far northwest 21Z and beyond.

With some decent sunshine for at least the first half of the day,
feel that MOS is too cold. Went closer to a raw model blend of
temperatures.

&&

.SHORT TERM.../Tonight through Tuesday night/
Issued at 304 AM EDT Sun Sep 25 2016

Focus is on chances for rain. Models are close enough that a blend
was used.

The cold front will move through the area tonight. An upper jet will
provide additional forcing while 850mb winds over 30kt bring in
additional moisture. Decent frontogentical forcing will be around as
well. Thus went likely PoPs most areas at some point during the
night, with later timing in the east.

Current expected timing of the system keeps rain still likely over
the east 3/8 of the area or so during the early part of the morning.
However, dry air moves in rapidly, so that by 15Z most areas are dry
and by 18Z everywhere is. Instability on Monday looks quite low so
removed any thunder mention.

Dry conditions should then prevail through Tuesday high pressure
nosing in.

An upper low will begin to move south out of the Great Lakes late in
the period. Models differ on path and how far south the rain gets by
late Tuesday night. Forcing doesn`t look impressive, and given the
uncertainty, was only comfortable adding in slight chance PoPs in
the extreme northeast forecast area.

For temperatures, generally stayed close to the model blend. Given
the dry air that will be in place for much of the short term, there
should be some decent diurnal ranges. The blend captures this pretty
well.

&&

.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 the 25/0600Z TAF Issuance/...

Issued at 1222 AM EDT Sun Sep 25 2016

Expect to see some fog develop in the next several hours with mostly
clear skies and light winds. Mainly expect MVFR visibilities for a
few hours until after daybreak. Think KIND will not drop lower than
that due to dry advection from easterly component flow. Other sites,
though, may be west enough to not get the drier air in and could fog
a little more. Confidence in this lower scenario still is not high,
though, and a few parameters still suggest that stratus will form.
May include a tempo IFR at KBMG and KHUF. Precipitation could move
into the sites before the end of the extended TAF portion, but
probabilities prior to 6z on the 26th are low enough that no mention
in the TAFs is necessary yet.

&&

.IND Watches/Warnings/Advisories...NONE.

&&

$$

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



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