Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kind 222000 
afdind

Area forecast discussion
National Weather Service Indianapolis in
400 PM EDT Fri Jun 22 2018

Update...
the synopsis...near term...short term
and long term sections have been updated below.

&&

Synopsis...
issued at 232 PM EDT Fri Jun 22 2018

Scattered showers and thunderstorms will continue to impact
central Indiana through tomorrow as a broad area of low pressure
rotates over the lower Midwest. As this low pushes farther
northeast tomorrow, rain chances will start to diminish across the
north, but low chances will remain across the southern counties
into Sunday due to a frontal boundary over the Tennessee Valley.
After a bit of a lull from Sunday into Monday, activity will once
again increase early next week with the next low pressure system.
Further out, dry conditions can be expected from Wednesday night
through Thursday before additional shower and thunderstorm chances
late in the extended period.

&&

Near term /tonight/...

Issued at 232 PM EDT Fri Jun 22 2018

The main focus of the near term period will continue to be
convective potential as well as a flash flood threat (mainly
north).

Currently, Sat/radar imagery indicate a broad area of showers and
thunderstorms rotating around a low pressure system situated over
the Illinois/Indiana border. Severe weather is unlikely, but
cannot rule out an isolated strong to severe pop-up storm through
the evening hours, so will continue to monitor. In addition,
localized flooding will remain a threat throughout the near term
period, but decided to hold off on a Flash Flood Watch since the
system will be pushing out of the area early in the short term
period.

Temperatures tonight will generally be in the mid 60s, which was
handled best with a model blend.

&&

Short term /tomorrow through Monday/...

Issued at 232 PM EDT Fri Jun 22 2018

The highest chances for rain will become concentrated over the
northeast quadrant of central Indiana tomorrow as the
aforementioned low pressure system pushes farther northeast. By
tomorrow night, the northern counties will become dry and focus
then turns to the southern counties where additional
shower/thunderstorm chances will be possible from Saturday night
into Sunday due to a frontal boundary draped across the Tennessee
Valley. After that, dry conditions will prevail from Sunday night
into Monday with just low chances over the southwestern counties
as the frontal boundary shifts across Missouri. Meanwhile,
temperatures through the period will start out below normal,
climbing back to or above normal late in the period.

&&

Long term /Monday night through Friday/...

Issued at 232 PM EDT Fri Jun 22 2018

The extended timeframe begins with an approaching upper level trough
moving toward the Great Lakes region from the northern plains
states. Increased rainfall chances influenced by this upper level
disturbance and associated near-surface frontal structure begins
Monday night/early Tuesday morning over the northwest reaches of the
forecast area. Forecast models are in decent agreement with regard
to there being an increased chance for rain associated with this
system through Wednesday. The GFS and European model (ecmwf) begin to diverge in
solutions after that with the European building a strong upper ridge
over the Ohio River valley. The GFS depicts an upper ridge building
back but not to the amplitude that the European depicts. Lowered
pops in the Wednesday night and after portion as confidence not high
in either solution coming to pass. Stuck close to the initialization
blend for temps though. With that said...above normal temps
categorize the extended timeframe.

&&

Aviation /discussion for the 22/1800 taf issuance/...

Issued at 138 PM EDT Fri Jun 22 2018

Mainly VFR conditions to start the timeframe except at bmg where
showers were pulling away to the north...leaving ceilings around
2000-2500 feet. Only have those persisting thru 1900z. However,
would not be surprised though if the lower ceiling hung on a bit
longer. Also put in a near term tempo group for laf as showers
continue to develop on and near a boundary in the area. Convection
should eventually impact the remainder of the taf sites this
afternoon into the evening. Huf and bmgs areas look to be the next
that may be impacted by convection in the next hour or two. If a
heavier shower or storm does impact one of the
terminals...expect a drop to MVFR or IFR conditions. Confidence
not high that any particular terminal will actually see convection
after lafs near term chance. Thus, continued with thunderstorms in the vicinity to handle.
MVFR ceiling then expected to push in this evening after
approximately 23/0300z.



&&

Ind watches/warnings/advisories...none.

&&

$$

National Weather Service Glossary of Abbreviations