Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 250450
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1250 AM EDT THU AUG 25 2016

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

&&

.SYNOPSIS...
Issued at 440 PM EDT Wed Aug 24 2016

A series of front and/or upper disturbances will keep chances for
showers and thunderstorms in the forecast for much of central
Indiana into next week. Temperatures will be near to above average,
and humid conditions will continue.

&&

.NEAR TERM /Tonight/...

Issued at 931 PM EDT Wed Aug 24 2016

Tail end of vorticity center currently passing into northwest Ohio is
lingering over the northeast zones. Should see a diminishing trend to the
convection in that area over the next couple of hours as this vorticity
tail moves off into Ohio.

Otherwise, this evening`s upper air and wind profilers indicate around 30 kts
of flow at the 850mb level, so potential exists for additional convective
development later tonight. Previous forecast handles this well.

Will make a decision by 250200Z on whether to cancel the remaining portions of
the Tornado Watch.

Previous discussion follows.

Due to severe weather the discussion will be short.

Upper system across Illinois will continue to produce scattered
convection across the area into early evening. Then there should be
a lull until perhaps a convective complex moves into northwest
sections late tonight.

Will go chance PoPs most areas, diminishing into early overnight.
Ramped back up late into low likely far northwest and chance
elsewhere.

&&

.SHORT TERM /Thursday through Saturday/...
Issued at 440 PM EDT Wed Aug 24 2016

Due to severe weather the discussion will be short.

A cold front will move through on Thursday but upper support is
weak. A potential thunderstorm complex could impact the far
northwest early in the day. Will go slight chance to chance PoPs
most areas, except likely early far northwest.

Kept low PoPs Thursday evening then dry as front sags south. Went
slight chance south Friday with front nearby. As a little upper
support returns along with the front Saturday went low PoPs.

Stuck with model blend on temperatures.

&&

.LONG TERM /Saturday Night through Wednesday/...

Issued at 218 PM EDT Wed Aug 24 2016

The blended forecast from the Regional initialization can be used
with moderate confidence.

The models generally agree in depicting a short wave trough moving
across the Great Lakes early in the period with a frontal
boundary gradually sinking south across our area Monday and
Tuesday. Prior to the fronts arrival in warm and unstable air
with upper troughing aiding in lift...expect the potential for
scattered convection. Once the front moves in and across the area
Monday the storm threat will be slightly higher. As that front
settles south of our area heights remain high and with humidity
still lingering...day time heating may still trigger some
isolated storms. By Wednesday another upper trough approaching
from the west will return a slightly higher storm threat and
slightly higher coverage as well.

With relatively high heights this will be a relatively warm
period with lows in the upper 60s or lower 70s...similar
to guidance...while highs generally reach mid 80s to around
90. Once the front moves through these readings will only drop a
category with lows into the low/mid 60s and highs mid 80s.
Dewpoints will only be slight drier.

&&

.AVIATION /Discussion for the 250600Z TAFS/...
Issued at 1250 AM EDT Thu Aug 25 2016

This evening`s upper air and wind profilers indicate a 25-30 kt low
level jet across the area. This may result in an increase of convective
potential in the vicinity of the terminals over the next few hours
as the low level jet increases. Confidence in direct impacts is low at
this time, but it appears the best threat will be in the KLAF vicinity.
Convective threat should diminish after sunrise Thursday as the low level
jet diminishes. Brief IFR visibility restricitions in the heavier cells.
CB bases around 030.

Otherwise, despite the narrow dewpoint depressions, convective potential
overnight should help keep the air mass mixed up enough to prevent
widespread or prolonged IFR visibility restrictions in fog.

Surface winds 200-230 degrees at 5-8 kts overnight will become 220-240
degrees by midday Thursday with occasional to frequent gusts around 18 kts.

&&

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

$$

SYNOPSIS...50
NEAR TERM...50/JAS
SHORT TERM...50
LONG TERM....TUCEK
AVIATION...JAS/JH



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