Area Forecast Discussion
Issued by NWS Indianapolis, IN

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149
FXUS63 KIND 150228
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1028 PM EDT Sat Oct 14 2017

.UPDATE...
The AVIATION section has been updated below.

&&

.SYNOPSIS...
Issued at 309 PM EDT Sat Oct 14 2017

A cold front will bring showers and a few thunderstorms to central
Indiana late tonight into Sunday morning. Much colder air will flow
in behind the front on Sunday with falling temperatures. High
pressure will then provide dry conditions into the first half of
next weekend. Temperatures will be below average Monday, then
gradually warm to above average by mid to late week.

&&

.NEAR TERM.../Rest of Tonight/
Issued at 939 PM EDT Sat Oct 14 2017

High Resolution Rapid Refresh and radar trends suggest line of
storms with the southern extent near Bloomington, Illinois, will
move just north of Warren and Carroll counties in the next few
hours. Will have to keep an eye on this though as confidence it will
not graze either county. Otherwise, the next line of storms,
currently over northeastern Missouri and west central Illinois,
should reach Warren county after 2 am, which matches the current
grids nicely.

Previous discussion follows...
Issued at 309 PM EDT Sat Oct 14 2017

The remainder of the afternoon will be dry and warm across the area
with a good flow of warm air from the south. Better moisture
transport from the 850mb jet will remain west and north of the area,
keeping the showers and thunderstorms northwest of central Indiana.

The evening will remain dry as well with the cold front and low
level jet remaining to the west. However, as both move into the area
overnight, chances for rain will increase from west to east. By the
end of the tonight period, the western third of the area will see
likely PoPs, with lower PoPs east.

There will be a threat for some thunderstorms tonight ahead of the
front with some warm and moist air in place across the area, but by
the time the main forcing gets here instability will be pretty low.
There could be some wind gusts over 45 mph if the storms can bring
down some of the strong winds aloft, but at the moment am not too
concerned with severe storms.

The pressure gradient will tighten up as the front approaches, so
winds will become gusty with gusts near 30 mph possible by late
tonight.

Temperatures will remain warm overnight with southerly flow. Went
near or a little above the model blend.

&&

.SHORT TERM.../Sunday through Tuesday/
Issued at 309 PM EDT Sat Oct 14 2017

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

The front will move through the area Sunday morning, bringing
showers and isolated thunderstorms. The low level jet will have
brought up good moisture, and forcing will the front will be good as
well. Thus went likely or higher PoPs all areas during the morning.
Rain will cut off quickly behind the system, so went dry all areas
18Z onward.

With a decent pressure gradient across the area, strong winds aloft,
and cold advection, expect gusty winds during the day. Wind gusts
around 35 mph are possible, especially across the northern forecast
area.

Temperatures may rise a degree or two west in the morning, with
perhaps a few more degrees east ahead of the front. Temperatures
will then fall through the rest of the day with the cold advection,
with readings in the 50s by mid afternoon.

High pressure will then build in and bring dry conditions Sunday
night through Tuesday. Concern then focuses on frost potential late
Sunday night and again Monday night. Latest model blend has come in
warm enough that frost shouldn`t be a problem, except perhaps for
sheltered low lying areas. However, the NAM is cooler than the rest,
and if it were to verify, frost would be more of a problem. Will
have to watch closely.

&&

.LONG TERM /Tuesday Night through Saturday/...
Issued at 145 PM EDT Sat Oct 14 2017

The coming week will be much more like fall with prolonged dry
weather and mild temperatures as high pressure dominates the area.
Highs should gradually climb from the mid 60s into the low to mid
70s during the week.

Blended initialization handled things well and only minor tweaks
were required.

&&

.AVIATION /Discussion for 15/03Z IND TAF Update/...
Issued at 1028 PM EDT Sat Oct 14 2017

No changes needed to the TAF.

Previous discussion follows...
Issued at 705 PM EDT Sat Oct 14 2017

Good confidence in VFR conditions through 10z and no weather through
08z. Low level wind shear will be a concern through around 14z as a
35-45 knot low level jet moves in from the west ahead of the
advancing strong cold front.

Confidence in convection is highest from 08z-17z along and ahead of
the front and also instability progs support VCTS 08z-12z.

South winds 7 to 13 knots will become southwest and jump up to 15
knots or so and with gusts to near 25 knots as the front gets close.
Behind the front, winds will become west and northwest 15 knots or
so with gusts to near 30 knots possible.

&&

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

&&

$$

SYNOPSIS...50
NEAR TERM...50/MK
SHORT TERM...50
LONG TERM...Nield
AVIATION...MK



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