Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 242050
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
350 PM EST Sat Feb 24 2018

.UPDATE...

The Synopsis, Near Term, and Short Term sections have been
updated below.

&&

.SYNOPSIS...
Issued at 350 PM EST Sat Feb 24 2018

A frontal system will bring additional rainfall, a few
thunderstorms, and perhaps a strong to severe storm or two to
central Indiana tonight, before high pressure in the wake of the
cold front allows some time for the area to dry out early in the
week. Additional rain chances can be expected mid to late week
with another low pressure system.

&&

.NEAR TERM /Tonight/...
Issued at 350 PM EST Sat Feb 24 2018

The next slug of rainfall associated with a leading upper wave and
the surface low is on our doorstep and will be overspreading the
area over the next few hours. Will go with 100 pops early in the
evening, tapering them off steadily from west to east after
midnight as the front sweeps through the area.

Embedded thunder will be a threat at times, particularly this
evening, and potential will exist for a few strong to severe
storms in the strongly dynamic environment. However,
destabilization thus far has been minimal across the area, which
will help to limit threat. Still, will have to keep a close eye on
storms particularly across the south this evening for wind or
perhaps a brief spinup.

Another round of rainfall will again contribute to a worsening
hydrologic situation across the area, and will continue the flood
watch as is. Expect an additional 1 to perhaps 2 inches of rain
across the watch areas, which will likely push portions of the
White, East Fork White, and other smaller rivers into moderate
flood, along with the Wabash which is receiving high water from
upstream. Additionally, poor drainage areas and smaller streams
will be in danger of flash flooding this evening with any
thunderstorms which may produce quick bursts of high rain rates.

Consensus temperatures were generally acceptable with only minor
tweaks.

&&

.SHORT TERM /Sunday through Tuesday/...
Issued at 350 PM EST Sat Feb 24 2018

High pressure will dominate the area through the short term, with
clear skies and quiet weather.

Consensus temperatures generally appeared to be in the ballpark,
save for Sunday. Lowered them a bit as with the cold front moving
through early in the morning and cold advection ongoing much of
the day, this should limit warming somewhat.

&&

.LONG TERM /Tuesday Night Through Saturday/...
Issued at 209 PM EST Sat Feb 24 2018

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

Upper energy will eject out of the southwestern USA early in the
period, leading to an upper low moving across the forecast area on
Thursday. As this moves out at the end of next week, upper ridging
will move in.

The upper system will lead to the development of a decent surface
low, forecast to be around Chicago by Thursday afternoon.

The result for central Indiana will be rain chances starting later
Tuesday night and continuing through Thursday night. Dry weather
then looks to move in to end next week.

Above normal temperatures will continue through Thursday, then near
normal readings can be expected behind the low pressure system.

&&

.AVIATION (Discussion for the 242100Z TAF Update)...
Issued at 316 PM EST Sat Feb 24 2018

Continued with predominant IFR, although there will likely be some
brief periods of higher ceilings the next couple of hours. The rain
will move back in and lower things back to IFR before 00Z.

Previous discussion follows...

Poor flying conditions expected during the first half of the
period, then a gradual improvement to VFR by 12Z Sunday.
Thunderstorms are possible most sites mainly 01-07Z.

First surge of rain will be diminishing at valid time. Upstream
observations show IFR ceilings are common, so will go with IFR as
predominant all areas. However, there may be some breaks to as high
as VFR at times into mid afternoon.

Second surge of rain will move in from the southwest after 22Z or so
and then persist through the evening. IFR ceilings and some IFR
visibility will occur with this rain, along with embedded
thunderstorms. Low level wind shear will develop as a cold front
approaches later this evening.

The rain will move out overnight, and ceilings will gradually
improve as drier air works in. Winds will gust to over 25kt
overnight into Sunday morning.

&&

.IND WATCHES/WARNINGS/ADVISORIES...

Flood Watch through Sunday morning for INZ030-031-035>049-
051>057-060>065-067>072.

&&

$$

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



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