Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kind 201404 
afdind

Area forecast discussion
National Weather Service Indianapolis in
1004 am EDT sun Oct 20 2019

Update...
the aviation section has been updated below.

&&

Synopsis...
issued at 242 am EDT sun Oct 20 2019

A weakening front will dissipate over the area today. A stronger
cold front is expected to move through the area Monday afternoon
and Monday evening. In the wake of this front, high pressure will
build in for the middle parts of the week. Another frontal system
may affect the area by the later parts of the week.

&&

Near term /today/...
issued at 242 am EDT sun Oct 20 2019

A weakening surface boundary is expected to drift into the local
area later this morning, before washing out this afternoon.
Current radar indicates there may a few sprinkles across parts of
the area, but haven't seen any ground reports yet. This activity
should pass off to the east by sunrise.

Otherwise, deep moisture and forcing appear insufficient for an
appreciable pop today.

Low level thicknesses generally support the GFS MOS high today, so
little if any adjustments planned.

&&

Short term /tonight through Tuesday night/...
issued at 242 am EDT sun Oct 20 2019

Models suggest a deepening upper trough over the plains tonight
will lift out towards Hudson Bay by the end of the short term. An
associated cold front is expected to pass through the local area
Monday afternoon into Monday evening.

Models suggest the fringes of the better lift will probably be
approaching the western border zones towards dawn Monday. Will go
with some chance pops over these areas by the pre dawn hours of
Monday.

Strong lift, aided by a 45 kt low level jet, is progged to move
through the area on Monday ahead of front. This should result in
fairly widespread precipitation on Monday. Will go with high pops
at that time. Lapse rates, and resultant instability, look rather
poor Monday, although deep layer shear will be strong. Potential
exists for high winds to mix down with any deep convection that
may form.

Models suggest the stronger lift may pass off to the east by
sunset Monday, but prefer to hold onto pops through the late
evening hours of Monday, until cold front passes off to the east.

Will go dry by Tuesday as the surface low lifts off into Canada,
and surface high pressure slides into the Tennessee Valley.

Progged low level thicknesses suggest the GFS MOS temperature
guidance over the next couple of days looks reasonable for the
most part, so any adjustments will be minor.

&&

Long term /Wednesday through Saturday/...

Issued at 303 am EDT sun Oct 20 2019

At the beginning of the long term, high pressure will be sliding
across the southeastern U.S. And its influence will reach to
Indiana bringing dry conditions and near normal temperatures. A
front could slide into the northern counties as early as Wednesday
overnight, but models are still not in agreement on any precip
with this feature and for now the majority of guidance looks dry
with the surface front. At the moment, have kept dry conditions
going until small chances for showers move into the area Thursday
night associated with a bit of upper forcing.

Ensembles show quite a bit of spread for the end of the week and
the weekend. Some members are showing a strong upper low settling
in over the Great Lakes bringing cold air spilling down into
central Indiana, but others are developing a strong upper low over
the southwestern U.S. That keep southwesterly flow over the area
through the weekend which would keep temperatures near normal.
Thus low confidence forecast from about Friday Onward. As a
result, made no appreciable changes to the nbm initialization.

&&

Aviation /discussion for the 20/15z taf update/...

Issued at 1003 am EDT sun Oct 20 2019

Update...
no flight category changes at kind, but did lower winds to calm.

Previous discussion...
mainly VFR today with ceilings around 4000 to 5000 ft or so.
Possible exception to this is at klaf where lower ceilings showing
up on satellite loop manage to get are enough south to bring
ceiling to MVFR. If this happens it should only last an hour or
two.

Clouds will increase overnight and rain will move in to the area
on Monday. After a day of light winds today, Monday will see wind
gusts develop by late morning into the 20 to 30 kt range.

&&

Ind watches/warnings/advisories...none.

&&

$$

Synopsis...jas

National Weather Service Glossary of Abbreviations