Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 212226

Area Forecast Discussion
National Weather Service Indianapolis IN
626 PM EDT Wed Jun 21 2017

The AVIATION Section has been updated below.


Issued at 324 PM EDT Wed Jun 21 2017

Chances for showers and storms will increase across the area through
the day and evening on Thursday as the remnants of Cindy provide a
stream of moisture rich air and some forcing to the area that will
then interact with a cold front trying to progress across central
Indiana. After rainfall and chances for storms lasting through
Friday, the cold frontal passage will usher in cooler, drier air to
last through the weekend and into the work week.


.NEAR TERM /Tonight/...

Issued at 324 PM EDT Wed Jun 21 2017

Diurnal pop up storm development remains possible through the
afternoon and evening hours with a weak surface front stalled out
over the area. May consider a slight chance for thunderstorms over
much of the area for the next few hours, with the expectation that
any development would be isolated in nature and unlikely to be able
to sustain itself. Then could see some small chances for showers and
storms early during the tonight period with a weak upper wave moving
southeast to interact with the aforementioned front. With increasing
cloud cover expect to see lows stay up in the upper 60s to around 70.


.SHORT TERM /Thursday through Saturday/...

Issued at 324 PM EDT Wed Jun 21 2017

Moisture will move north from the remnants of Cindy during the short
term and interact with a frontal boundary to bring rain and storm
chances to central Indiana. Models are in fairly good agreement that
any precip chances will stay south of the forecast area until late
morning and then increase throughout the afternoon from south to
north and moisture and forcing move up from the aforementioned
remnants. The highest probability for rain and storms as well as the
heaviest rainfall amounts will occur late Thursday night into Friday
morning. The axis of heaviest rainfall should remain south of the
forecast area. Expect to see a decent gradient in rainfall amounts
from northwest to southeast, with perhaps a quarter inch or so
northwest but up to a couple of inches across the southeastern
counties. Regardless, as long as the storm track for Cindy remnants
doesn`t suddenly take a northward jog, current forecast rainfall
amounts do not pose any sort of significant flooding hazard for
central Indiana.

Friday the cold front will move through the area, and Friday night
it should sweep rain and storm chances out of the area from the
northwest to southeast. By early Saturday morning central Indiana
should be dry with drier dewpoints and cooler air advecting in.

For temperatures, look for mid 80s to around 90 on Thursday with the
lower end of temperatures in the south due to cloud cover spreading
north. Friday only low 80s expected with ample cloud cover and
precipitation across the area. For Saturday will see cooler highs in
the mid to upper 70s.


.LONG TERM /Saturday Night through Wednesday/...

Issued at 211 PM EDT Wed Jun 21 2017

Beginning of the forecast period a broad mid/upper level trough
will be across the central and northeastern U.S north of the
middle MS/TN Valleys. The GFS swings an embedded and weakening
short wave trough from the Upper MS Valley into the lower Great
Lakes through late Sunday night, while the ECMWF is slower with
this feature taking it through the lower Great Lakes by Sunday
afternoon. The embedded short wave trough may set off some widely
scattered showers as it moves across the lower Great Lakes.

Surface high pressure will be over the central Plains and extend
eastward through the Ohio Valley late Saturday through Tuesday
which will keep area dry with the exception of Sunday afternoon
with the weak mid/upper trough. Expect below normal (highs in the
mid 80s) temperatures through the much of the period with a
little warm up back into the low-mid 80s on Wednesday.

Confidence: Low Confidence with Sunday precipitation.


.AVIATION /Discussion for the 220000Z TAFS/...
Issued at 626 PM EDT Wed Jun 21 2017

Scattered convection over southern Indiana in association with an
instability axis, and mid level vorticity center drifting through
west central Indiana. As a result, there will be a threat for
convection in the vicinity of mainly KBMG until around 220100Z.

Another mid level vorticity center is progged to migrate out of
eastern Iowa into northern Indiana later tonight. Some of the
short term model guidance suggests a convective threat may develop
in the KLAF vicinity after about 220500Z, but potential for direct
impacts are too low to mention at this time. Will monitor
convective trends off to the northwest during the evening.

Otherwise, diurnal clouds based around 040 expected to dissipate
with sunset. Scattered to broken layers above 050 tonight.
Surface winds 200-240 degrees at 6-8 kts early this evening will
diminish to 6 kts or less after dark.




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