Scientific Forecaster Discussion
fxus63 kind 171634
Area forecast discussion
National Weather Service Indianapolis in
1234 PM EDT Thu Oct 17 2019
the aviation section has been updated below.
issued at 324 am EDT Thu Oct 17 2019
High pressure will cause dry conditions through Saturday.
Temperatures will start out below normal and increase through the
start of next week. Chance of rain as a weak front pushes through
followed by a better chance of rain and thunderstorms Monday and
Tuesday with a cold front moving through. Some storms Monday could
be strong to severe. Temperatures will drop to near normal behind
the cold front.
Near term /rest of today/...
Issued at 932 am EDT Thu Oct 17 2019
Only minor adjustments needed with the forecast trending well.
Bumped up sky cover for a few hours across the northeastern
counties with more widespread cloud cover present than initially
expected. Also lowered high temperatures by a degree or two
across the board with continued strong cold air advection ongoing.
Previous discussion follows...
High pressure building into the region will lead to dry conditions
today. Temperatures will be below normal thanks to northwesterly
flow. Some clouds will move in this morning, particularly for the
northeast half of the forecast area, but skies are expected to be
clear again by this evening.
Short term /tonight through Saturday night/...
Issued at 324 am EDT Thu Oct 17 2019
High pressure and dry conditions continue through Saturday
morning. Areas of frost are possible Thursday night as light winds
and lows in the mid-30s are expected. Temperatures will increase
each day as warm air advection affects the region, reaching above
normal on Saturday.
A weak front will push across the state Saturday afternoon and
evening leading to a chance of rain. There remain discrepancies
between models on whether the rain will reach central Indiana. The
Euro has been the most aggressive with including pops whereas the
GFS continues to show the rain dissipating before the front gets
here. Due to continued lack of confidence, lowered guidance pops
slightly for Saturday.
Long term (sunday through wednesday)...
issued at 300 am EDT Thu Oct 17 2019
Models are close enough that the National blend of models
initialization was accepted for most items.
Sunday looks to be dry with central Indiana in between systems.
A large upper system will produce a strong surface low well to the
northwest of the area Monday. A strong cold front will extend from
this low and move across the area around Monday. The system will
have a strong flow from the south at 850mb, which could bring in
decent instability. With the strong wind flow and potential
instability, strong to severe storms still look to be possible.
The issue still is in the exact timing of the system, which could
impact severe potential. The uncertainty in timing will also impact
pops, and this has resulted in the initialization keeping pops below
the likely category for most areas. It will rain at some point
around Monday, and pops will increase once the specifics become
Pops will diminish Tuesday as the system exits. High pressure should
then build in for the remainder of the long term and keep things
Temperatures should surge ahead of the strong system, with above
normal temperatures expected Sunday and Monday. Below normal
readings will move in for Tuesday and Wednesday.
Aviation /discussion for 17/18z taf issuance/...
Issued at 1224 PM EDT Thu Oct 17 2019
VFR conditions expected through the taf period.
Dry conditions are expected with high pressure in place. The
diurnal cu field that is currently building will last through the
evening before dissipating before 0z. Winds will generally be out
of the north at 7-10 kts this afternoon before weakening to near
calm later tonight.