Scientific Forecaster Discussion
fxus63 kind 180320
Area forecast discussion
National Weather Service Indianapolis in
1120 PM EDT Thu Oct 17 2019
the aviation section has been updated below.
issued at 331 PM EDT Thu Oct 17 2019
The clear, cool conditions will continue tonight with a high
threat for frost formation as high pressure remains over the
region. The dry conditions will continue into Saturday with a weak
warming trend, but then the first of two frontal systems will
impact central Indiana late Saturday and Saturday night. After a
lull in activity on Sunday, a second more potent system will
enter the region on Monday. Strong to severe storms could
accompany the frontal passage on Monday. Further out, dry and
cooler weather will return for most of the extended period.
Near term /tonight/...
Issued at 331 PM EDT Thu Oct 17 2019
The main focus of the near term period will be frost formation.
Significant radiational cooling with the clear skies will lead to
overnight lows in the mid 30s tonight. And, with the light
northwest winds, frost formation will be a concern. So, will carry
a frost advisory late tonight across all of central Indiana. Frost
could kill sensitive outdoor vegetation if left uncovered.
Short term /tomorrow through Sunday/...
Issued at 331 PM EDT Thu Oct 17 2019
The large ridge of high pressure will influence central Indiana
weather through tomorrow and into Saturday. It will, however,
break down Saturday afternoon as an upper low enters the upper
Midwest. Meanwhile, at the surface, a weak frontal boundary will
be responsible for low rain chances Saturday/Saturday night. Will
also not rule out a few embedded thunderstorms across the southern
counties where instability could be a tad better.
The aforementioned rain chances will come to an end rather quickly
though with all rain out of the forecast area by sun 06z. At that
point, dry conditions will return through the remainder of the
A weak warming trend will occur through the period with daytime
highs increasing from the low to mid 60s on Friday to low to mid
70s by Sunday. Overnight lows will climb from the 40s into the
Long term /Sunday night through Thursday/...
issued at 323 PM EDT Thu Oct 17 2019
Active weather to start at the beginning of the week will bring a
threat for severe storms...windy conditions and much needed
rainfall...followed by a dry and cooler stretch through the end of
the extended that will begin a stepdown process to much colder
weather by the last week of the month.
Models continue to align on a strong surface low kicking out of
the northern plains late weekend and into the upper Midwest on
Monday as an occluded system. Cold front arcing from the low will
sweep across the Ohio Valley Monday afternoon and evening and
bring the potential for a higher impact convective line moving
across the forecast area. Gulf moisture will surge north into the
region ahead of the front and with strong dynamics aloft...
potential is there for a squall line producing severe weather and
locally heavy but much needed rainfall. In addition...plenty of
wind will accompany the frontal passage. Will continue to
highlight The Hazards with this system via the severe weather potential statement.
Much drier and cooler air will overspread the region quickly in
the wake of the frontal passage...with high pressure influencing
the weather for much of the rest of the extended. Highs will slip
back to the 50s Tuesday and low to mid 60s Wednesday and Thursday
with lows in the upper 30s and lower 40s. Another strong storm
system looms on the horizon for just beyond the 7 day...with the
potential for much colder weather by next weekend in its wake.
Aviation /discussion for 18/06z taf issuance/...
issued at 1120 PM EDT Thu Oct 17 2019
High confidence in VFR conditions with clear skies per trends, GFS
lamp and sref.
Winds will be light and variable except southeast and south up to 7
knots at klaf and khuf after 17z.
frost advisory from 2 am to 8 am EDT Friday for inz021-028>031-