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Area forecast discussion 
National Weather Service Indianapolis in
930 am EST Monday Jan 26 2015

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

&&

Synopsis...
issued at 332 am EST Monday Jan 26 2015

A cold start to the week is expected across central Indiana. A weak
upper level wave will bring some light snow to the region late this
afternoon and tonight. Dry weather returns Tuesday into midweek as
high pressure moves through the Ohio Valley. Weak low pressure
systems will track through the lower Great Lakes Wednesday night and
Thursday...and again over the weekend...bringing chances for
precipitation.

&&

Near term /today/...
issued at 332 am EST Monday Jan 26 2015

Light snow ended across central Indiana shortly after midnight and
as low pressure moves into the central Appalachians and away from
the region...wind gusts beginning to drop off as well. Cold morning
with 08z temperatures in the teens and lower 20s north to middle and upper 20s
south.

Stratus remains across the forecast area but clearing attempting to
make its way south and expect some sunshine this morning as weak
surface ridging builds into the Ohio Valley behind the departing
low. Clouds will return however by early afternoon for most as a
weak quick moving upper wave dives into the region. This feature is
producing light snow over the upper Mississippi Valley early this
morning...and expect it to do likewise as it spreads into the Wabash
valley by late afternoon. Model soundings do show drier air within
the boundary layer which may mitigate the light snow somewhat...but
still feel low probability of precipitation are warranted over the western half of the
forecast area by late day.

Temperatures...despite sunshine through midday...cold advection will limit
temperature rises. Generally a degree or two shy of mavmos guidance for
highs this afternoon...with exception of far northeast counties
where there is a few inches of snow. Temperatures may struggle to get to
the middle 20s in these areas.

&&

Short term /tonight through Wednesday night/...
issued at 332 am EST Monday Jan 26 2015

Forecast challenges focus on light snow tonight followed by precipitation
chances Wednesday night as low pressure moves into the lower Great
Lakes.

Vorticity lobe associated with steadily weakening upper wave will
transition across central Indiana tonight as the energy aloft dives
into the parent upper trough. Dry air within the lower levels and
only subtle isentropic lift will likely limit a more substantial
light snowfall...but presence of the middle level forcing cannot be
ignored. In addition with slightly elevated ratios...potential
certainly exists for a light accumulation of a dusting up to a half
inch or so focused for areas along and west of I-65. Further
east...lower levels even drier which may keep much more than
flurries from falling. Light snow should end from north to south
towards daybreak Tuesday. While amounts will be very light...still
could be enough to create slippery conditions for drivers Tuesday
morning.

Bulk of the rest of the short term at least through Wednesday
evening will be quiet as broader area of high pressure builds into
the area. With the cold advection and cyclonic flow Tuesday...may
have some difficulty completely getting rid of stratocu until late
day and have maintained mostly cloudy skies. Expect clearing skies
for Tuesday night into Wednesday...with increasing middle/high level
clouds by late day moisture spills over the expanding upper ridge
and into the region.

Low pressure will track out of the Central Plains late Wednesday...
moving into the area by daybreak Thursday. Moisture will steadily
increase with precipitation developing as the wave approaches.
Surface temperatures could be a factor with respect to precipitation type at
onset...especially over the northeast half of the forecast area.
Expect lows during the evening with temperatures steadily rising thereafter
as warm advection takes hold. Conceivably could see a brief period
with freezing rain...but confidence is low with the NAM and sref as
the only guidance really hinting at the possibility with a more
suppressed track to the surface low. Rest of the model data
generally brings surface temperatures above freezing over the course of the
night with rain becoming the primary precipitation type. Will maintain a
rain/snow mix over northeast half otherwise expect mainly rain at this
time.

Temperatures...undercut mavmos by a degree or so Tuesday then took a MOS
blend for highs Wednesday. Leaned much closer to warmer met guidance
tonight with cloudy skies. Went above mav guidance for lows
Tuesday/Wednesday nights.

&&

Long term /Thursday through Sunday/...
issued at 248 am EST Monday Jan 26 2015

For the most part...models are close enough that the superblend
initialization was accepted for most items.

A low pressure system will bring chances for rain to central Indiana
on Thursday. As this system pulls away Thursday night there could be
some lingering light snow as some colder air moves in.

Friday will be dry...but chances for precipitation return for the
first part of the weekend. Models differ on timing of
precipitation...so stayed close to superblend given the uncertainty.
The best chances for precipitation will be Saturday night as a
cold front moves through.

Left Sunday dry for now...but would not be surprised to have to add
in a low pop Sunday with cold advection and perhaps a slower moving
system per latest trends.

After a warmer Thursday temperatures will be seasonable Friday and
Saturday. For Sunday went colder than superblend and closer to the
colder European model (ecmwf) /and wpc/ as GFS has been trending colder anyway.

&&

Aviation /discussion for the 261500z kind taf update/...
issued at 930 am EST Monday Jan 26 2015

Minor tweaks made to kind taf to better match current conditions.
No other changes are needed at this time.

Previous aviation discussion follows...
MVFR returns to VFR this morning...but MVFR conditions are expected
again this evening.

Edge of low clouds has cleared klaf and is moving southeast. Expect
kind to become VFR by 14z and kbmg by 16z. Additional low clouds are
upstream of khuf and will keep them MVFR through 16z.

During the afternoon middle cloud will thicken and lower...especially
across the western sites as another system approaches. Could be some
light snow trying to move into western sites late this
afternoon...but believe most of this will dry up before reaching the
ground.

As the system moves in this evening best chances for any snow will
be at the western sites. Added vcsh there. Otherwise MVFR ceilings
will be the rule this evening and overnight.

&&

Ind watches/warnings/advisories...none.

&&

$$

Synopsis...Ryan
near term...Ryan
short term...Ryan
long term....50
aviation...50/jh

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