Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 301652
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1252 PM EDT Fri Sep 30 2016

.UPDATE...
The Near Term section has been updated below.

&&

.SYNOPSIS...
Issued at 925 AM EDT Fri Sep 30 2016

A strong upper level Low Pressure system over kentucky is expected
to slowly drift north across Indiana today and Saturday. This will
be cloudy...cool...and showery weather to Central Indiana for the
first half of the weekend. Thunderstorms will also be possible,
mainly during the afternoon and early evening.

On Sunday...the low is expected to drift farther north to the
eastern Great Lakes...as High Pressure build across the
Mississippi River Valley...bringing near seasonal temperatures and
dry weather for much of the next work week.

&&

.NEAR TERM /Today/...
Issued at 1252 PM EDT Fri Sep 30 2016

Marginal risk area has change and includes our northeasternmost
counties with the southernwesternmost area northeastern Boone
county. Current radar loop was showing the strongest echoes in an
arc moving northwest over this area. Updated Hazardous Weather
Outlook and will update Weather Story to reflect this.

Previous discussion follows...
Issued at 925 AM EDT Fri Sep 30 2016

Added to the Hazardous Weather Outlook mention of possible severe
storms this afternoon through 8 pm near and east of a Muncie to
Greensburg line. All types of severe weather are possible per the
Day1 SPC Outlook. Also, updated the Weather Story to reflect this.

Previous discussion follows...
Issued at 207 AM EDT Fri Sep 30 2016

Surface analysis early this morning shows Low pressure over the
Carolinas...with north/northeast flow across Central Indiana.
Water vapor imagery shows a deep and large cut-off low in place
over Kentucky...influencing much of the weather across the eastern
third of the United States. Radar mosaics show scattered showers
arriving across Central Indiana from the east...flowing around the
upper low to the south.

GFS suggests the upper low will slowly begin to meander northward
across Indiana today and tonight. Forecast soundings show deep
saturation through the day...but limited instability. Time heights
also show excellent lower level saturation. Thus with ample
moisture and forcing expected given the upper pattern...will raise
pops today and keep showers in the grids. Cannot rule out a rumble
of thunder as well....but widespread storms are not expected.
Given the expected clouds and rain will trend highs closer to the
3 hourly guidance values.

&&

.SHORT TERM /Tonight through Sunday Night/...
Issued at 207 AM EDT Fri Sep 30 2016

Wet weather looks to persist through at least Saturday as the
upper low slowly treks across Indiana. Forecast soundings and Time
height sections continue to indicate saturation within the column
through the period. Thus will continue the ongoing trend through
the period of raising pops...with low temps warmer than guidance
and highs cooler. Given limited heating during the overnight
hours...will try to keep isolated thunder mention to the daytime
hours.

Changes arrive by late on Sunday...as GFS and NAM suggest ridging
over the Mississippi River valley nudging the broad low to the
northeast. Dry air begins to enter the column as forecast
soundings begin to dry out on Sunday. Thus as the moisture and
forcing departs...will begin to trend toward a dry forecast for
Sunday and Sunday Night. Will work a blend on Highs for Sunday and
lows on Sunday night.

&&

.LONG TERM /Monday through next Thursday/...
Issued at 229 AM EDT Fri Sep 30 2016

Ensembles in fairly good agreement with the expected weather
pattern during this period. Upper ridge initially over the Ohio
Valley early next week will gradually shift east as an upper
trough lifts northeast towards the upper Mississippi Valley by the
middle of next week.

A weakening cold front associated with the western trough is
expected to possibly begin affecting the local area by next
Wednesday or Thursday. Timing differences exist with this front,
with some of the members suggesting front may not make it into the
area by next Thursday. Will keep some PoPs in the forecast for
mainly Wednesday night and Thursday for now.

&&

.AVIATION /Discussion for the 301500Z IND TAF Update/...
Issued at 1020 AM EDT Fri Sep 30 2016

Added tempo IFR ceilings through 16z as has been the trend. A few
showers were nearby so left VCSH in.

Previous discussion follows...
Issued at 631 AM EDT Fri Sep 30 2016

Should be a relative lull in shower activity for a period this
morning as some mid level drier air wraps around the upper low.
Shower activity expected to pick up again towards midday and on
into the afternoon as a vorticity lobe rotates in from the
southeast. Convective parameters suggest scattered thunderstorms
may form as well given the cold pocket aloft. CB bases near 020.
Brief IFR visibility restrictions in heavier cells.

Otherwise, areas of IFR ceilings 006-009 AGL have been developing
across the area over the past couple of hours. These ceilings may
affect the terminals on occasion through the mid to late morning
hours, before boundary layer heating and incoming vorticity lobe
allow these ceilings to lift and mix out.

Surface winds 010-030 degrees at 5-8 kts this morning expected to
gradually veer around to 020-060 degrees at 6-10 kts by later this
afternoon. Surface winds may become light and variable in the KBMG
area towards evening as a surface trough lifts north towards southern
Indiana.

&&

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

$$

SYNOPSIS...PUMA/MK
NEAR TERM...PUMA/MK
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS/MK



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