Area Forecast Discussion
Issued by NWS Indianapolis, IN

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090
FXUS63 KIND 010716
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
316 AM EDT WED JUN 1 2016

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

&&

.SYNOPSIS...
Issued at 316 AM EDT Wed Jun 1 2016

A cold front will bring chances for showers and thunderstorms to
central Indiana today into tonight. Most of the area will stay dry
Thursday and Friday, then a couple of fronts will bring more rain
chances for the weekend into early next week. Above normal
temperatures will gradually cool to below normal by early next week.

&&

.NEAR TERM.../Today/
Issued at 316 AM EDT Wed Jun 1 2016

Scattered showers and thunderstorms were across Illinois with an
upper wave and an approaching cold front. At the moment most
convection was moving more north than east.

The front (and a pre-frontal trough) will move into the area during
the day today. Convection developed yesterday across the area.
Better moisture will flow into the area today, and forcing will be
stronger than yesterday with the front moving in. Some sunshine
today will help build instability today.

Given the above, believe scattered to numerous showers and
thunderstorms will develop. Went likely PoPs across the north, where
forcing will be a bit better as the north is closer to the forcing
from an upper trough. Timed highest PoPs in the afternoon, when
better forcing and instability are present.

Per the Storm Prediction Center, a few strong to severe storms are
possible across the area, with a Marginal Risk across the northwest
half or so.

Went above MOS temperatures for highs today given recent trends and
some sunshine expected today, especially east.

&&

.SHORT TERM.../Tonight through Friday night/
Issued at 316 AM EDT Wed Jun 1 2016

Focus is on chances for rain through the period. Models are close
enough for the most part that a blend was used.

Although the pre-frontal trough will be east of the area, the actual
cold front will still be moving through tonight. Continued chance
PoPs during the evening and then gradually ending them overnight.

Still some uncertainty on how far south the front will get Thursday
and thus if any of the area will see rain. With most models and
ensemble members keeping any rain only in the far south, went slight
chance PoPs in those areas.

Thursday night and Friday it still appears front will be far enough
south to keep the area dry.

Models continue to differ on rain chances returning north Friday
night as they differ on the approach of an upper trough. NAM/GFS
(and the GFS ensembles) keep rain out of the south, while
ECMWF/Canadian bring rain back in with a more southerly flow aloft.
00Z ECMWF has backed off some from the 12Z run though.

With the uncertainty, and blending in with neighboring offices, left
the previous forecast pretty much alone to keep continuity and avoid
potential flip-flopping. This means low chances for most of the area.

For temperatures, generally stuck with a blend.

&&

.LONG TERM /Saturday through Tuesday/...
Issued at 242 AM EDT Wed Jun 1 2016

The main focus of the extended period will be the transition to a
cooler and at times more unsettled weather pattern as an upper
trough amplifies over the region.

Best chances for rain throughout the period expected on Saturday
into Saturday night. Scattered convection will be possible as
deeper moisture is drawn north into the Ohio Valley and interacts
with low pressure and a cold front diving through the Great Lakes.
Chances for showers and storms will persist into Sunday as the low
moves slowly east through the Great Lakes and additional energy
aloft dives into the upper trough. The arrival of a secondary cold
front serving as the leading edge of even cooler air on Monday
warrants a continued mention of chance pops.

High pressure will build in beginning Monday night and should
maintain dry conditions for the region through the middle of next
week. Cooler than normal conditions will persist however as the
Ohio Valley remains in a northwest flow aloft on the back side of
the upper trough. After a warmer day Saturday ahead of the initial
cold front...highs are likely to be only in the low to mid 70s
Sunday through Tuesday with slow warming taking place beyond the 7
day.

&&

.AVIATION /Discussion for 010600Z TAF Issuance/...
Issued at 1220 AM EDT Wed June 01 2016

Good confidence that VFR conditions will continue through the
overnight and most of the rest of the period. Would not rule out
brief MVFR or worse conditions in thunderstorms after 12z as showers
and storms increase in coverage ahead of an approaching cold front.
Went with VFR showers in the prevailing group after 12z and through
around 21z. Also...models suggest plenty of instability...so have
prob30 thunder groups through 21z and VCTS after...until the cold
front passes. The front looks to reach Laf and Huf around 03z
Thursday IND and BMG around 06z.

Winds will be light and variable overnight and south and southwest 6
knots or less during the day today and west and northwest 6 knots or
less in the wake of the cold front.

&&

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

&&

$$

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



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