Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 160301
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1001 PM EST Thu Feb 15 2018

.UPDATE...
The NEAR TERM and AVIATION sections have been updated below.

&&

.SYNOPSIS...
Issued at 400 PM EST Thu Feb 15 2018

A cold front will drop through the area tonight, bringing
continued opportunity for rainfall and perhaps a rumble of thunder
or two to the area. Rain chances will end Friday morning as the
front exits the area. High pressure will provide a brief dry
period before precipitation chances return Saturday into Saturday
evening as an upper level disturbance pushes through the area.
More substantial rainfall is likely early next week as another
stronger frontal system moves through the region. Flooding appears
likely to develop along area rivers next week as a result of this
rainfall.

&&

.NEAR TERM /Rest of Tonight/...
Issued at 1001 PM EST Thu Feb 15 2018

Line of convection is moving through the southern forecast area,
with occasional gusts to 50 mph and brief heavy rain. This should
exit the area later this evening. Behind the line, rain extends well
back into the northwest forecast area. Thus have continued high PoPs
most areas. PoPs will gradually diminish from northwest to southeast
during the night as forcing diminishes.

Right behind the cold front (currently across the far northwest
forecast area), there is a thin area of fog with visibility below 2
miles. At the moment do not believe this will become an issue as
drier air works in, but will continue to monitor.

Adjusted hourly temperatures based on latest data, but overall
temperature forecast looks good so made no changes to low temps.

Previous discussion follows...

Frontal boundary is currently on our doorstep to the northwest,
and will slowly but steadily drop through the area tonight. Warm
moist airmass ahead of the front will provide ample opportunity
for additional rainfall, and at least an outside shot at a rumble
of thunder or two.

Southern portion of the area is in a marginal risk, and this isn`t
unreasonable given the extreme shear. Mesoanalysis indicates that
instability is marginal at best however, and oftentimes in these
highly sheared environments updrafts struggle to maintain
themselves without more robust instability, thus expect any
convective activity to amount to little more than a few rumbles of
thunder. Will carry a slight chance of thunder into the early
evening before removing mention altogether.

Will steadily taper pops throughout the night as the front moves
southward.

Consensus temperatures appeared reasonable and were generally
accepted.

&&

.SHORT TERM /Friday through Sunday/...
Issued at 400 PM EST Thu Feb 15 2018

Precipitation will be coming to an end Friday morning, and it now
appears likely that this will occur in time to prevent any
snow, although a flake here or there cannot be entirely ruled out.

Dry weather will be the rule Friday afternoon into Friday night,
before another low pressure system moves through the region
Saturday into Saturday evening. This may begin as a few snowflakes
before temperatures warm enough Saturday to transition to all
rain. The reverse may be the case Saturday evening, but suspect
that blends are hanging on to low pops a bit too long.

The remainder of the short term will be dry.

Consensus temperatures were generally acceptable outside of
Friday, when highs should be not much warmer than overnight lows
tonight, and temperatures will likely be slowly falling much of
the day as cold advection is ongoing.

&&

.LONG TERM /Sunday Night through Thursday/...
Issued at 320 PM EST Thu Feb 15 2018

Very wet and mild weather will occur late Sunday night through
Tuesday night.  Models indicate an area of low pressure will track
from Iowa into the great lakes by Monday and a frontal system will
move southeast across Indiana Tuesday.  Have added a slight chance
of Thunder most areas early Tuesday ahead of the cold front.

The front will stall across the middle Atlantic states and Tennessee
as high pressure moves east into the great lakes.  The GFS and 12Z
European keep all of our area dry Wednesday night and Thursday
...while the Canadian is more aggressive in spreading precipitation
back to the north by Thursday.  Will mention low chance POPS in the
south these periods which matches the blend.

Temperatures will be unseasonably mild Monday and Tuesday...then
cooling to slightly above normal Wednesday and Thursday.  In most
cases stayed close to a MOS blend on temperatures.

&&


.AVIATION (Discussion for the 16030Z TAF Update)
Issued at 1001 PM EST Thu Feb 15 2018

Although rain will continue for a while at KIND, conditions appear
to be VFR. Allowed for a couple of hours of VFR, then brought in low
MVFR ceilings. Will have to watch to see if upstream IFR ceilings
hold together though.

Previous discussion follows...

Generally MVFR conditions expected for much of the first half of the
TAF period, then VFR returning by early afternoon Friday.

Radar shows convection beginning to develop in east central Illinois
at the moment. This convection will spread east and south, impacting
mainly the southern 3 TAF sites. There will be some scattered
thunderstorms in the convection, but at the moment feel that the
odds are too low to mention in the TAF. Will reevaluate at issuance
time.

Conditions will deteriorate to MVFR in the convection, with brief
IFR periods possible. As a cold front moves south through the area
this evening, winds will shift to the northwest.

Variable conditions between MVFR and VFR expected overnight into
Friday morning, then VFR will return.

&&

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

&&

$$

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


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