Scientific Forecaster Discussion
fxus63 kind 182029
Area forecast discussion
National Weather Service Indianapolis in
429 PM EDT Tue Jun 18 2019
the aviation section has been updated below.
issued at 354 PM EDT Tue Jun 18 2019
An active weather pattern will not let up over central Indiana,
continuing to bring bouts of heavy rain and chances for severe
storms to the area. Unfortunately for many waterlogged areas across
central Indiana, the next seven days continue this pattern.
Near term /this evening and tonight/...
Issued at 354 PM EDT Tue Jun 18 2019
Some scattered showers with a few thunderstorms will continue
through the afternoon and into the evening across much of central
Indiana, with more coverage across the southern counties. These
showers and storms are moving fairly slowly, and will be monitoring
closely for flood/flash flood potential especially given the already
saturated ground and low flash flood guidance values there.
This is mainly diurnally forced convection, and thus should see
coverage diminish towards sunset and dissipate within an hour or two
after. Northwest and central western counties are likely to remain
dry from now through the overnight.
Cloud cover will decrease after sunset as well and thus should see
low temperatures in the low to mid 60s. May see some patchy fog
development after midnight especially in locations that see rain
Short term /Wednesday through Friday/...
Issued at 420 PM EDT Tue Jun 18 2019
A low pressure system will approach from the southwest on Wednesday
and bring a front back into central Indiana. The low will move along
the front Wednesday and move through central Indiana Wednesday night
and then off to the northeast on Thursday.
This feature will bring more heavy rain to the state by Wednesday
afternoon and through Wednesday night into Thursday which will make
ongoing flooding problems worse, and thus the Flash Flood Watch
continues through Thursday night.
Precipitable water values will continue to run high, and additional
rainfall amounts of 2 to 4 inches from Wednesday through Thursday
morning is not unreasonable, with locally higher amounts feasible.
Of course flash flooding will not be the only threat on Wednesday.
A slight risk for severe weather is in place over southwest parts of
the area. This is focused on the location of the warm front lifting
back into the area, so given that, could see a tornado threat again
near the front. Otherwise for anywhere not along the front, think
the main threat will be damaging winds. Shear and instability will
be maximized around 0z across most of the area, so think the best
chances for severe will be in the 4-10 PM range with cams indicating
some potential for a squall line going through during the early
Thursday models are showing some differences in timing out the exit
of the low, and thus carried some pops through the afternoon toward
a middle of the Road solution. However some runs are faster and
could be dry during the afternoon. Thursday night should be dry
across the area, and this could extend into the day on Friday. Again
by Friday afternoon, seeing some model differences in timing of the
arrival of the next system, so currently have dry forecast through
the day but this is low confidence. High temperatures will generally
be running near normal for this time of year with the exception of
Thursday, where mostly cloudy and possibly showery conditions
through the day could keep highs in the low to mid 70s.
Long term /Friday night through Tuesday/...
issued at 254 PM EDT Tue Jun 18 2019
More of the same as this stagnant pattern holds into next week.
Between the combination of a favorable flow regime aloft as ridging
remains largely focused just to the south and the return of another
frontal boundary set to become parallel to the upper level flow...do
not see an end in sight to the active...unsettled and unfortunately
wet pattern through the extended.
Trying to time out the best chances for rain and storms in this
pattern as well as provide more detail is challenging. While no day
will likely be a washout...going to need to carry rain/storm chances
every day through the long term with the passage of surface and
upper waves triggering periodic convective complexes impacting
Considering we have reached a point where any rain is a problem in
parts of the area...greater and more widespread flooding impacts
will continue to rise through the period. Some of the analogs for
Saturday and Sunday carry ominous hints towards higher impact
flooding events from the past to impact central Indiana. Additional
chances for severe weather will exist through the extended as well.
And to add potentially to the misery...it appears a warmer and more
humid airmass will settle over the Ohio Valley through the weekend
and into early next week.
Aviation /discussion for 182100z taf issuance/...
issued at 429 PM EDT Tue Jun 18 2019
Updated current conditions only. Previous discussion follows...
Mainly VFR conditions through the evening before additional
restrictions develop in fog and low ceilings late tonight and early
Scattered convection firing on cue early this afternoon and should
linger over parts of the forecast area into the evening before
diminishing. Expected coverage warrants no higher than a vcsh
mention the rest of the afternoon. Brief restrictions are possible
with any shower or storm that comes across a terminal.
Model soundings show saturated conditions in the near surface layer
overnight with areas of fog and low ceilings redeveloping.
Expecting the potential for MVFR and possibly sub-IFR conditions
into Wednesday morning. Should see ceiling improvements during the
morning with potential for convection to develop near the end of the
forecast period as a surface wave approaches.
Flash Flood Watch through Thursday evening for inz037-039-045>049-