Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 230158
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
958 PM EDT FRI JUL 22 2016

.UPDATE...
The NEAR TERM Section has been updated below.

&&

.SYNOPSIS...
Issued at 355 PM EDT Fri Jul 22 2016

A large ridge over much of the nation will keep a hot and humid
airmass in place across central Indiana through the weekend.
Isolated thunderstorms cannot be ruled out, although most areas
appear likely to be dry through the early portion of the weekend.
A frontal boundary will approach the area later in the weekend
into next week, increasing the thunderstorm chances, primarily
late in the weekend into Monday, and from mid week onward. This
boundary will bring some slight relief from the heat.

&&

.NEAR TERM /Overnight/...
Issued at 958 PM EDT Fri Jul 22 2016

Muggy conditions continue with mainly clear skies this evening as
the forecast area residing on the edge of the heat ridge. 0130Z
temps largely remained in the lower to mid 80s.

Soundings showing some instability present above a well developed
cap sitting between 5kft and 9kft. Drier mid level air has
advected into the region from the north in the wake of the upper
level wave that has moved into the Tennessee and lower Ohio
Valleys. With ridging aloft strengthening overnight and 700mb
temps hovering at 11-12C...do not see available low level moisture
or instability above the cap being sufficient enough to generate
even any isolated convection across central Indiana. Plan on
removing pops for the rest of the night as a result.

Primary focus as the night progresses is likely to focus on areas
of fog developing with the stagnant flow and deep moisture present
within the lower levels of the atmosphere. Have introduced fog into
the grids after 06Z across the entire forecast area. Expect
another steamy night with lows in the mid to possibly upper 70s
and dewpoints in the 70s.

Zone and grid updates out.

&&

.SHORT TERM /Saturday through Monday/...
Issued at 355 PM EDT Fri Jul 22 2016

Will increase pops to 30 Saturday afternoon as there is at least
some chance that remnant circulation or boundaries from prior
convection to our west would be able to spark slightly more
expansive activity across our area, but again with a lack of
substantial upper level support and 700 mb temps remaining 10 to
12C, expect that widespread organized convection is unlikely
through Saturday evening. There is some indication that as the
frontal boundary approaches and the ridge weakens slightly, more
substantial thunderstorm activity could move into the area late
Saturday night into Sunday, followed by the front itself, which
will necessitate increased thunderstorm chances Sunday into
Monday. Significant uncertainty remains, obviously, as this will
depend heavily on how convective activity lays out over the next
24 to 36 hours.

Consensus temperatures appeared reasonable, although did bump them
up slightly, particularly tomorrow when models appear to be
overdoing potential coverage of precip.

Model dewpoints have been slightly too aggressive in recent days
and bumped them down slightly, but this still results in peak heat
indices Saturday and Sunday in excess of 100 across the entire
area, and in excess of 105 in portions of central Indiana. Will
continue heat advisory through Saturday as it currently stands.
May require extension into Sunday, but this will depend
significantly on thunderstorm activity which as previously
mentioned remains highly uncertain.

&&

.LONG TERM /Monday night through Friday/...
Issued at 212 PM EDT Fri Jul 22 2016

Models are in fairly good agreement except for faster return
of rain by the GFS later next week relative to other models.
Will use a blended solution.
1236
A frontal boundary pushing south of the forecast area at the
start of this period brings an end to very warm, humid and
occasionally stormy pattern of recent and upcoming days. High
pressure bridging across the Great Lakes into the Ohio valley
Tuesday and Wednesday will produce more seasonal and dry weather
for most of our area as the front stalls in southern Kentucky.

The next weather system begins approaching Wednesday night or
Thursday depending on model and strength of this system is quite
variable also. All models indicate a return of the front into the
southern Great Lakes on Thursday and a return to more unsettled
wet pattern for 24 to 48 hours. Potential for an inch or two of
rain with this but confidence is very low this far out.

Blended temperature solutions looked pretty comparable to
current forecast and was followed.

&&

.AVIATION /Discussion for 23/0000Z TAF Issuance/...

Issued at 652 PM EDT Fri Jul 22 2016

Running with VFR conditions at this time and should remain so
through 23/02Z this evening. High pressure to our southeast will
be in control overnight and winds should remain very light/calm.
Given that surface dew points are 69-74 deg across much of the
area, temperatures should fall within 1-2 deg of those dew points
which will set up for a widespread fog situation after 23/06Z.

Limited visibilities will result in IFR to MVFR through the
morning hours as heating will dissipate the fog, but low clouds
will be around through mid morning before breaking up for the
afternoon.

&&

.IND Watches/Warnings/Advisories...
Heat Advisory until 8 PM EDT Saturday for INZ021-028>031-035>049-
051>057-060>065-067>072.

&&

$$

SYNOPSIS...NIELD
NEAR TERM...RYAN
SHORT TERM...NIELD
LONG TERM...TUCEK
AVIATION...DWM


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