Area Forecast Discussion
Issued by NWS Indianapolis, IN

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079
FXUS63 KIND 271825
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
220 PM EDT Mon Mar 27 2017

.UPDATE...
The LONG TERM Section has been updated below.

&&

.SYNOPSIS...
Issued at 306 AM EDT Mon Mar 27 2017

A series of low pressure systems will bring rain chances today and
then every few days into early next week. Temperatures will
generally be near normal to above normal through the period.

&&

.NEAR TERM.../Today/
Issued at 306 AM EDT Mon Mar 27 2017

Central Indiana is currently in between precipitation areas. However
that will change later this morning and especially this afternoon as
a surface low pressure area and upper trough approach from the west.

Rain is currently back across Missouri and Kansas. Isentropic lift
will begin to increase across the forecast area later this morning
as the systems approach. Hi-res models show better chances arrive in
the far southwest forecast area about 15Z and this looks reasonable.

PoPs will gradually spread northeast across the area today, but
forcing could initially be split into the afternoon. The northwest
forecast area will see better chances as a boundary sits near there,
while southern area see forcing from some upper energy ahead of the
main system. This leaves lower chances across the northeast. Tried
to show this trend with the hourly PoPs.

By 00Z most areas will have likely or higher PoPs.

The better instability across the forecast area will be across
southern sections of the area. Have seen indications in the hi-res
model data of a potential MCV impacting the southern forecast area
late in the afternoon, which could aid in the thunderstorm
development.

The Storm Prediction Center has moved the Slight Risk out of the
forecast area due to instability concerns. However, a Marginal Risk
remains across the southern half of the area.

For temperatures, stayed with the model blend.

&&

.SHORT TERM.../Tonight through Wednesday night/
Issued at 306 AM EDT Mon Mar 27 2017

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

Likely or higher PoPs will continue across the forecast area this
evening with the upper trough and surface lows moving through. Could
still see some strong or severe storms across the south early in the
evening.

Chances for rain diminish overnight with the exit of the system, and
some low PoPs will linger into Tuesday morning until the system`s
influence is no longer felt.

Dry conditions will then prevail Tuesday night into Wednesday with
some upper ridging moving through. However, the approach of yet
another system Wednesday night will bring some isentropic lift to
the area. This will lead to some low PoPs overnight Wednesday night.

The model blend temperatures look reasonable given expected
conditions.

&&

.LONG TERM /Thursday night through Monday/...

Issued at 220 PM EDT Mon Mar 27 2017

Timing of showers will be the main focus for the long term.

The general weather pattern will remain the same through the long
term with alernating Pacific upper lows and ridges. Each upper low
will dive southeast across dessert southwest and southern Plains and
then lift northeast over the Ohio Valley.

Thursday night will start off with the first upper low over the
Ozarks. It will open up and move east over the Ohio Valley on
Friday. Southerly flow along and ahead of the associated frontal
system will bring deep moisture and some instability to the area as
well as synoptic forcing. Thus, expect widespread showers and a few
thunderstorms from Thursday night through Friday. An upper ridge
will follow and should keep the weather quiet from early Saturday
through Sunday morning. Then, the next in the upper train will bring
shower chances back to central Indiana by Monday.

Low level thermal progs and expected cloud cover support slightly
above normal blend temperatures with highs in the mid 50s to mid
60s.

&&

.AVIATION /Discussion for the 27/1800Z TAF Issuance/...

Issued at 138 PM EDT Mon Mar 27 2017

VFR conditions will linger through the afternoon hours. However,
rain showers are quickly streaming into the TAF sites with the
threat of thunderstorms not far behind as a low pressure system
approaches from the southwest. As a result, expect conditions to
deteriorate to MVFR this evening and possibly even IFR overnight
with some fog formation. MVFR conditions also cannot be ruled out
in any of the heavier showers this afternoon. Meanwhile, winds
will be southeasterly for most of the TAF period, then shift to
the north behind the aforementioned low pressure system. Sustained
speeds will generally be 5 to 10 kts outside of any convection.

&&

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

&&

$$

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



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