Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kind 161100 
afdind

Area forecast discussion
National Weather Service Indianapolis in
600 am EST Sat Dec 16 2017

Update...

The aviation section has been updated below.

&&

Synopsis...
issued at 350 am EST Sat Dec 16 2017

A mild and quiet day is expected today under the influence of high
pressure off to the southeast. A quick moving upper level wave
will bring some rain showers to the area Sunday, with low chances
for rain or drizzle lingering Sunday night into Monday as
additional weak disturbances aloft pass through the region. The
next widespread chance for precipitation will come toward week's
end as a frontal system moves through the area.

&&

Near term /today/...
issued at 350 am EST Sat Dec 16 2017

Quiet weather expected today with the area under the influence of
high pressure off to the southeast and broad southwest flow in
place across the area. While some mid and high cloud may be
present initially, expect skies to become mostly clear today.
Ample sun and strong warm advection should allow temperatures to
rise well into mid 40s to low 50s across the area, a bit above
consensus numbers, especially given its tendency to underdo
changes in advection regimes.

&&

Short term /tonight through Monday night /...
issued at 350 am EST Sat Dec 16 2017

The main focus for the short term will be Sunday, as a compact
upper level wave moves through the area. Precipitation will be
a good bet, and while a brief mix of rain and snow at precip onset
cannot entirely be ruled out due to evaporational cooling effects,
this is looking less likely than previously and will keep grids
all rain. Even if a few flakes were to drop, the ground will be
well warmed by today's warmth and would anticipate no impact from
this.

Forecast soundings become drier aloft Sunday evening and beyond,
but blends do hold onto some very low pops across portions of the
area, particularly Monday morning as a weak wave passes through
the region. Could see a few showers or perhaps some drizzle and
will hold onto these low pops for now.

Consensus temperatures generally appeared in the ballpark per low
level thermal progs and required few tweaks.

&&

Long term /Tuesday through Friday/...
issued at 245 am EST Sat Dec 16 2017

The upper pattern transitions from a zonal upper flow with an
upper disturbance moving east across the southern U.S. Around the
middle of next week to a more amplified upper pattern Friday into
next weekend as an upper trough digs into the upper Midwest and
eventually the Great Lakes.

Both the GFS and gemnh models keep all precipitation well south
of Indiana...while the 00z brings it as far north as southern
Indiana late Wednesday and Wednesday evening. The 00z superblend
probability of precipitation had precipitation farther north based on the old Euro. Will
mention slight chance probability of precipitation far south late Wednesday and go dry
elsewhere.

Models develop an area of low pressure over the Southern Plains
move it into the southern Great Lakes Friday. Will lean toward the
slower Euro and Canadian models. Looks like rain will develop
Thursday night and become mixed with snow north and northwest
sections by Friday. Could see falling temperatures Friday as colder
air arrives.

Raised superblend temperatures a little Thursday and Thursday night
as we will be mostly in the warm sector. Otherwise...superblend
temperatures seem reasonable most other periods.

&&

Aviation /discussion for the 16/12z tafs/...
issued at 600 am EST Sat Dec 16 2017

VFR through the period.

Mid cloud is exiting the area this morning and expect skies to be
mostly clear much of the period. A gradual increase in mid and
high cloud will begin late in the period as the next system
approaches the area. Cannot rule out some showers at ind in the 30
hour period but too low probability for inclusion this far out.
Precipitation will become more likely after the end of the taf
period.

Winds will generally be southwesterly through the period.
Sustained winds may be as high as 10-11kt this afternoon with
gusts into the low 20kt range. Winds will weaken in typical
diurnal fashion this evening, but remain 5-9kt overnight.

No obstructions to visibility expected during the period.

&&

Ind watches/warnings/advisories...none.

&&

$$

National Weather Service Glossary of Abbreviations