Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 250620
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
220 AM EDT MON JUL 25 2016

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

&&

.SYNOPSIS...
Issued at 220 AM EDT Mon Jul 25 2016

A cold front over the Illinois and northern Missouri will sag
southward toward the Ohio River today...providing clouds and
perhaps a few showers or storms. Clouds associated with the e
front will prevent Highs in the 90s today.

Cooler and less humid air is expected to arrive in Central
Indiana tonight as High pressure over the northern plains states
builds southeast into the Ohio Valley. The High is then expected
to push across Indiana through mid week...providing dry weather.

More chances for precipitation will arrive across the region late
in the work week as another cool front and accompanying upper
level weather disturbance arrives in the area.

&&

.NEAR TERM /Today/...

Issued at 220 AM EDT Mon Jul 25 2016

Surface analysis early this morning shows Low pressure north of
the Great Lakes with a cool front extending southwest across
Northern Illinois to Northern Missouri. Radar shows a convective
complex ahead of the front over Central Illinois...building
southward across the land of Lincoln.

Current convective complex is expected to continue to wan across
central Indiana...where instability is not quite favorable. Better
CAPEs remains across southern Illinois...and backbuilding and
progression of the system is expected there. Still high clouds
will stream across Central Indiana this morning as the rain shield
is expected to continue its weakening trend as depicted by the
rapid refresh.

Models remain in pretty good agreement that the frontal boundary
will sag southward close to the ohio River Today. Forecast
soundings show better instability across the far souther parts of
the state this afternoon where the Front should arrive with a
warming and more unstable atmosphere. dew point temps across the
southern parts of the forecast area remain very moist...in the
middle and upper 70s. Thus will trend pops highs across the
southern areas...trending lower across the central and
north. Forecast soundings show good drying within the column
across the northern parts of the forecast area...particularly by
the afternoon.

Given the expected cloud cover from the passing front...will trend
highs toward the cooler side of a blend. No heat advisory needed
today.

&&

.SHORT TERM /Tonight through Wednesday Night/...

Issued at 220 AM EDT Mon Jul 25 2016

Dry and quiet weather is expected this period. Models suggest that
the surface high over the northern plains will slowly progress
through Indiana and the Great Lakes on Tonight through Wednesday
Night. Forecast soundings and time heights show a dry column
through the period with subsidence. Even CU will be quite limited
as convective temps appear to be close to 95 on Tuesday and 90 and
Wednesday. Aloft the upper flow looks to remain well north of
Indiana keeping most forcing well north of Indiana. Thus mostly
sunny days and mostly clear nights will be the way to go through
the period. Thicknesses and 850mb temps change very little
through...thus a blend of guidance will work. Temps on Wednesday
night should begin to trend warmer as Indiana arrives on the
backside of the now departing High pressure system.
Furthermore...high cloud approaching associated with the
approaching Low dropping out of the northern plains should begin
to limit cooling.

Of interesting to note...if heat island effects do not have much
an overwhelming effect...temps in Indy may fall below 70 on
Tuesday morning. This would be the first time below 70 since July
18th.

&&

.LONG TERM /Wednesday night through Sunday/...

Issued at 218 PM EDT Sun Jul 24 2016

Main challenge for the long term will be timing various upper waves
moving through and ahead of a mean Mississippi Valley trough.
Judging by the differences in the operational GFS and ECMWF and
individual ensemble spaghetti plot members, the confidence in
strength and timing of these waves is not good. For instance, the
00z and 12z GFS runs have a strong wave moving through Thursday
night, while the 00z ECMWF version is much weaker.  Thus, will
accept regional blend, which has chance pops Wednesday night through
Sunday.

Low level thermal progs support normal to slightly below normal
blend highs in the lower to mid 80s. Meanwhile, look for overnight
lows mostly be in the mid to upper 60s.

&&

.AVIATION /Discussion for 250600Z TAF Issuance/...
Issued at 1235 AM EDT Mon Jul 25 2016

Restrictions possible within convection otherwise predominantly VFR
conditions expected.

Convection has weakened considerably as it has tracked southeast
into the northern Wabash Valley where airmass is more stable than
that back across central and western Illinois and capping inversion
remains to some extent. Expect most direct impacts at KLAF for the
first few hours of the forecast. Confidence remains fairly low that
any convection will make it to KHUF and even less that it will make
it to KIND early this morning but will maintain VCTS wording at this
time. Storms are likely to diminish in coverage further or diminish
entirely predawn.

Expect scattered convection to refire this afternoon south of I-70
along and ahead of the cold front in the moist unstable airmass.
Will focus VCTS after 17-18Z at KBMG and KHUF where confidence is
highest in potential impacts. High pressure will build in from the
north late afternoon and evening with skies becoming mostly clear.
Winds will veer to light northerly tonight.


&&

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

$$

SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM....MK
AVIATION...RYAN/CP



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