Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 250440
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1235 AM EDT MON JUL 25 2016

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

&&

.SYNOPSIS...
Issued at 300 PM EDT Sun Jul 24 2016

One more relatively warm and humid day is expected
Monday before slightly cooler and less humid air filters
into our area Tuesday and Wednesday. The change in air mass will
be accompanied by scattered thunderstorms though not all
locations will receive this rain. The next weather system and
return of slightly warmer and humid air will bring a better
rain/storm coverage for the latter half of the week.

Temperatures for this period will start above normal then dip to
seasonal values for the balance of the week.

&&

.NEAR TERM (Tonight)...

Issued at 820 PM EDT Sun Jul 24 2016

The convection allowing models concur the storms now over Illinois
will eventually make it into the northwest CWA but probably not
all the way to the southeast. This is captured fairly well in the
latest hourly POPs from the CONSHORT model, which will be used
with the forecast update.

Precipitable waters remain very high. So does the freezing level,
suggesting a lot of warm rain process, which we have seen many times
in this air. Heavy rain will be mentioned in storms.

Guidance minimum temperatures a tad on the warm side the last few
days and will go just below those, but with winds to remain up a
little, minimums should be several degree warmer than this morning.


&&

.SHORT TERM /Monday through Wednesday/...

Issued at 300 PM EDT Sun Jul 24 2016

Models are in fairly good agreement on movement and position
of front over the next several days as high pressure takes over.
The front will move from just north of our area at daybreak
Monday to our southern counties by sundown. With the strongest
wind fields and best upper support well to the north and northeast
convection should be relatively scattered. Where storms do
develop expect heavy rainfall given our fairly high precipitable
water values.

Do not plan to add Heat Advisory for Monday with heat indices
at highest just over 100 in our southern counties. Monday will
still feel relatively warm and humid though. Will keep max temps
near guidance and previous forecast. Rain chances will likely
follow diurnal trend with better chances at peak heating and
along and ahead of southeast advancing cold front. Again given
best dynamics being well northeast would expect no more than
scattered convection and pops still in the chance category.

For Tuesday and Wednesday the frontal boundary will slip south
of the Ohio River. Current forecast of rain chances in
southern counties may be a bit pessimistic as high pressure may
more likely drive rain chances south of the Ohio River. Will keep
low chances for now but another model run may suggest their
removal.

Temperatures Tuesday and Wednesday still look fairly good with
mid and upper 80s appearing reasonable. Might be a tad high on
holding southern county dewpoints in the lower 70s. High pressure
scouring out the tropical air may reach south of our area by
Wednesday and may need future adjusting.

&&

.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...TUCEK
NEAR TERM...DT/JK
SHORT TERM...PUMA
LONG TERM....MK
AVIATION...RYAN/CP


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