Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 191032
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
632 AM EDT Mon Jun 19 2017

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

&&

.SYNOPSIS...
Issued at 321 AM EDT Mon Jun 19 2017

Upper waves will trigger showers and thunderstorms at times today
and tomorrow, mainly across the northernmost portions of the
forecast area. After that, a brief lull in activity will prevail
around mid-week before the pattern becomes more active again.
Shower and thunderstorm chances will resume on Thursday night,
lingering through the extended period as a frontal boundary
settles over the lower Great Lakes Region.

&&

.NEAR TERM /Today/...

Issued at 321 AM EDT Mon Jun 19 2017

The main focus of the near term period will be shower and
thunderstorm chances across the northern portions of central
Indiana as an upper wave moves into the area.

Dry conditions will prevail this morning, but shower and
thunderstorm chances will increase by afternoon across the
northern counties. Confidence is low in thunderstorm chances
though, so will only keep mention across the north-central
counties for now where forcing will briefly be strongest.
Elsewhere, the southwestern third of the forecast area will
remain dry for the near term period. Meanwhile, temperatures are
expected to range from the mid 70s (NE) to low 80s (SW).

&&

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

Issued at 321 AM EDT Mon Jun 19 2017

Dry conditions will return for the entire forecast area by tonight
as subsidence briefly increases. However, tomorrow will be very
similar to today with another weak upper wave traversing the area.
As a result, will carry slight chance pops across mainly northern
portions of the area on Tuesday afternoon and evening. After that,
weak ridging aloft will keep conditions dry from Tuesday night
through Wednesday. Wednesday night, latest Superblend
initialization skims the northern counties with a mention of
showers and thunderstorms, will keep this for now but confidence
is low.

A weak warming trend will commence during the period with highs
climbing back into the mid to upper 80s by Wednesday. Meanwhile,
overnight lows will start out in the upper 50s/low 60s tonight and
tomorrow night, then only drop into the mid 60s on Wednesday
night.

&&

.LONG TERM /Thursday through Sunday/...
Issued at 310 AM EDT Mon Jun 19 2017

Much of the extended period is likely to be active as a quasi-
zonal flow aloft brings multiple upper level waves through the
region and interacting with a frontal boundary setting up over the
lower Great Lakes.

After a dry start initially on Thursday...the front will settle
over the Ohio Valley and appears poised to bring multiple chances
for rain and storms to the region for late week into the weekend.
Extended model guidance remains out of sync with respect to
location of the front which makes employing additional detail
difficult at this point...but the overall upper level pattern
supports an unsettled weather regime for central Indiana and the
Ohio Valley. An additional wild card is the potential influence of
deeper Gulf moisture being drawn north into the Tennessee and
lower Ohio Valleys Friday and Saturday courtesy of a tropical
system moving onshore along the Gulf coast. Should the remnants of
this system lift into the Tennessee Valley as is being suggested
by some of the extended guidance...potential would be there for
an influx of rich tropical moisture into the Ohio Valley.

The approach of a stronger upper level low diving into the Great
Lakes will help to develop a deeper surface low which will finally
shift the front and the deeper moisture south of the area by late
weekend. A much cooler airmass is then poised to envelop the Ohio
Valley and Great Lakes for early next week as a broad upper trough
settles over the area.

&&

.AVIATION /Discussion FOR 191200Z TAF Issuance/...
Issued at 632 AM EDT Mon Jun 19 2017

VFR conditions expected throughout the forecast period.

Weak surface ridging this morning will maintain dry conditions and
mainly clear skies to start. The expansion of a broad upper trough
over the Great Lakes and a wave aloft traversing through the area
will interact with a weak surface boundary to generate scattered
cu this afternoon and a few showers and storms. Westerly winds may
become gusty at times through the afternoon as the surface
boundary swings through the forecast area.

Clouds will diminish tonight as high pressure overspreads the
region in wake of the upper wave and surface boundary. West/
northwest winds will diminish below 10kts overnight.

&&

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

&&

$$

SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....Ryan
AVIATION...Ryan



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