Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 160759
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
259 AM EST Fri Feb 16 2018

.UPDATE...
The LONG TERM Section has 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 /Monday through Friday/...

Issued at 255 AM EST Fri Feb 16 2018

A very wet and warm pattern is expected next week as
southwesterly flow persists across central Indiana. There will be
3 major systems with the first moving through Sunday night into
Monday, the second Tuesday night into Monday, and the third late
Friday.

A surface front will move through the state Tuesday night bringing
the heaviest rain for the period. There are significant timing
differences for the frontal passage between the models which
leads to the GFS and Canadian bringing the heaviest rain to
southern Indiana and the Euro keeping it further north. Kept POPs
and QPF broad-brushed for this forecast package to reflect the
uncertainty. Widespread minor to moderate flooding is likely next
week across the state as 2-4 inches of rain falls from Monday to
Wednesday on already saturated ground.

Temperatures will be unseasonably warm on Monday and Tuesday with
highs in the 60s. After the frontal passage highs in the mid to
upper 40s are expected through the rest of the week.


&&

.AVIATION (Discussion for the 160600Z TAF Issuance)...
Issued at 1129 PM EST Thu Feb 15 2018

IFR conditions expected early in the period, followed by periods of
MVFR.

The significant rain should be south of the terminals by valid time.
However, there is an area of IFR (and some LIFR) conditions in
stratus and fog behind the cold front (currently just north of
KIND).

Thus, for all but KLAF, will have a period of poor flying conditions
early in the period. These will improve to VFR for a while as drier
air works in, but MVFR ceilings will return from the north during
the morning in the cold advection pattern. These will persist for a
good part of the daylight hours before returning to VFR.


&&

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

$$

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



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