Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kind 200300 
afdind

Area forecast discussion
National Weather Service Indianapolis in
1000 PM EST Tue Nov 19 2019

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

&&

Synopsis...
issued at 308 am EST Tue Nov 19 2019

A series of systems will bring frequent rain chances to central
Indiana through Saturday, then dry weather will return for early
next week. Other than a brief period of above normal temperatures
around Thursday, temperatures will be near normal to below normal.

&&

Near term /tonight/...
issued at 940 PM EST Tue Nov 19 2019

Kept small chance pops in northeast half through 05z per radar and
ob trends.

Previous discussion follows...

Issued at 620 PM EST Tue Nov 19 2019

Raised pops and labled precip as drizzle through 02z.

Previous discussion follows...

Issued at 230 PM EST Tue Nov 19 2019

Water vapor imagery depicting short wave energy moving down the
backside of longwave trof axis this afternoon. Surface reflection
in the form of frontal wave continues to slide southeast down into
Kentucky. Kind radar continues to show large area of light rain moving
across the area with back edge of precip now entering western County Warning Area.
Previous grids were on track with timing precip to end this
evening so other than bumping up pops few changes were made.
Surface ridge builds into the area overnight but forecast
soundings indicating plenty of boundary layer moisture available
so expect low clouds to linger.

&&

Short term /Wednesday through Thursday night/...

Issued at 230 PM EST Tue Nov 19 2019

Quiet weather to begin the short term period with surface high
pressure centered over the Tennessee Valley bringing some sunshine to the
area and seasonable temperatures Wednesday. High pressure slides
east toward the mid-Atlantic region Wednesday night and will set the
stage for brief warm-up with return flow on the backside Thursday
as focus shifts to developing system in the plains as energy
ejects from closed low over SW US. Indications from deterministic
models have this southern stream energy breaking off and being
absorbed into more progressive northern stream flow rather than
phasing with the northern stream. This will have surface low
tracking from Central Plains to the Great Lakes region Thursday
and bring trailing cold front through the area. While consistent
signal exists among the ensemble members as well as the nbm for
the likelihood of precip...lack of phasing may very well result in
a split of both moisture and forcing. Mid-upper level forcing
associated with pronounced northern stream trof will be detached
well to the north across Great Lakes and southern Ontario while
surface high pressure remains anchored just off the Carolina
coast and diverts Gulf return moisture toward Southern Plains. End
result will have high pops but generally low quantitative precipitation forecast as front moves
across the area Thursday/Thursday night. Strong warm air advection pattern
setting up ahead of this system aided by 50kt low level jet will have temps
warming into the mid-upper 50s Thursday.

&&

Long term /Friday through Tuesday/...

Issued at 230 PM EST Tue Nov 19 2019

Forecast period to begin with additional southern stream energy
ejecting out of the SW US that will interact with frontal boundary
just south of the area. Best chance for additional precip from
this will be right at the onset early Friday morning with modest
push of isentropic ascent and moisture transport on 300k surface
right along and just behind surface cold front. Subsequent frontal
wave that develops expected to track south of the area but with
plenty of spread with both deterministic and ensemble
solutions...need to maintain low chance pops through Saturday
until better consensus reached. Cold air filtering in behind the
front will bring chance for snow and rain/snow mix Friday
night/Saturday morning as lows drop into the upper 20s north and
near freezing south. Quiet weather expected Sunday and Monday as
surface high pressure builds in across the southern US with
northern stream systems confined to southern Canada. Small chances
for precip return on day 7 as potent system poised to lift out of
the plains middle of next week.

&&

Aviation /discussion for 20/06z taf issuance/...
issued at 1000 PM EST Tue Nov 19 2019

The GFS lamp and sref and current trends now strongly support the
GFS lamp and sref MVFR and worse flying conditions, mostly ceilings,
through at least 16z Wednesday. This lends to good confidence in
poor conditions through late morning.

Winds will be light and variable or calm overnight and southeast up
to 6 knots late today..

&&

Ind watches/warnings/advisories...
none.
&&

$$

National Weather Service Glossary of Abbreviations