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Area forecast discussion 
National Weather Service Indianapolis in
911 PM EST sun Feb 1 2015

Update...

The aviation section has been updated below.

&&

Synopsis...
issued at 411 PM EST sun Feb 1 2015

A strong storm system will move across Indiana tonight
and away from the area Monday keeping precipitation in the forecast
and windy conditions through the night. High pressure will briefly
build in starting Monday afternoon and bring colder air with it but
another upper wave will approach Tuesday night bringing more snow
chances to the area through Wednesday night.

&&

Near term /this evening and tonight/...
issued at 411 PM EST sun Feb 1 2015

Low pressure centered near Effingham Illinois at 330 PM is moving
east toward western Indiana and will move through to Ohio tonight.
Rain is the predominant precipitation type across all but the far
northwestern counties where snow is still being reported. Rain will
continue off and on this evening for this area before snow mixes
back in tonight from northwest to southeast. Far northwestern
counties should see mainly snow but a heavy wet snow at that.

Later tonight as the area gets on the back side of the low could
see some deformation snow bands and this should be a lighter
fluffier snow. Could see another inch of accumulation or so during
the overnight in the north with around half an inch central. As
the low gets to the east the pressure gradient across the area
will be tight and expect winds to be very gusty through the
overnight especially in the north with gusts 25 to 35 miles per hour expected
and 40-45 possible. This could cause significant drops in
visibilities during even light snow showers...and for this reason
as well as temperatures dropping rapidly /lows in the teens north
and central/ and freezing of roadways have continued product
headlines as is. Not sure how far south the visibility problems
will extend so for now keep blowing snow mention north of I-70.

&&

Short term /Monday through Wednesday/...
issued at 411 PM EST sun Feb 1 2015

Low pressure will move away from the area on Monday but as high
pressure builds in could see some lake effect snow showers and
clouds in the northwestern counties. Don/T think much will
accumulate but thought it was Worth a slight chance for much of the
day there. Only other spot with probability of precipitation on Monday is the eastern
counties in the morning as the low pulls away. Winds will still be
pretty Stout early in the day with a strong pressure gradient across
the area. By evening though high pressure should be close enough to
drop winds somewhat. An upper wave and associated front will move
through the area Tuesday night and Wednesday bringing more chances
for snow...with the highest chances in the northern counties closest
to the best dynamic forcing.

For temperatures generally used a consensus average but decreased
them in the north where snow pack could have an impact.

&&

Long term /Wednesday night through Sunday/...
issued at 249 PM EST sun Feb 1 2015

Another quick moving upper wave will be exiting the area Wednesday
night and temperatures look cold enough that precipitation type
should not be a concern. Temperatures look plenty cold enough for
light snow at this time...and even though this is a bit far out in
the forecast around half an inch to upwards an inch of snow may be
possible through middle week. Arctic high pressure will then build in
behind the front and slowly move eastward across the region through
the end of the week...allowing dry but colder than normal conditions
to prevail for central Indiana. Saturday looks warmer as
southerly flow increases ahead of the next cold front. Guidance
appears to be in good agreement with the next system set to impact
the area beginning Saturday night and continuing into early next
week...with precipitation type possibly being an issue at times
through Sunday of next week. For now kept rain south of I 70 and
light snow north of here. Precipitation type issues can be dealt
with as this event gets much closer.

&&

Aviation /discussion for the 02/03z taf update/...
issued at 911 PM EST sun Feb 1 2015

Removed precipitation and visibility restrictions at ind for now. Previous
discussion follows.

Issued at 608 PM EST sun Feb 1 2015

Poor flying conditions expected at least through the next 12 to 18
hours as a winter storm system pushes through the area.

Widespread IFR conditions generally the rule across the area...and
this will continue unabated at most sites over the next several
hours...although some slight improvement is likely to
occur...especially in visibilities...as the low passes and winds
begin to increase and become gusty.

Significant precipitation is likely done at all but laf...where a
band of snow is likely to pass through later this evening bringing
visibilities back down to below a mile for a time. Showery rain
changing to snow expected if anything at the other sites.

Conditions will begin to improve more substantially by
morning...with sites becoming borderline MVFR/VFR or just VFR by
midday or early afternoon.

Winds will turn from westelry to northerly or northwesterly through
the period and gust overnight...perhaps up to or in excess of 30kt
at a couple of sites. These gusts will weaken around daybreak and
winds will continue to subside through the day.

&&

Ind watches/warnings/advisories...

Winter Weather Advisory until 7 am EST Monday for inz035>037-
039>043.

Winter Storm Warning until 7 am EST Monday for inz021-028>031-
038.

&&

$$

Synopsis...cp
near term...cp
short term...cp
long term...smf
aviation...nield

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