Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 241458

Area Forecast Discussion
National Weather Service Northern Indiana
1058 AM EDT Sat Mar 24 2018

Issued at 430 AM EDT Sat Mar 24 2018

Snow is expected today across central and parts of north central
Indiana, mainly near and south of a line from Rensselaer to
Monticello to Richmond Indiana. Accumulations could reach 4 to 8
inches over central Indiana creating travel difficulties today.
Amounts of 2 to 5 inches remain possible between Monticello and
Lafayette. Snow ends this evening with clearing skies from the
north. Low temperatures will be in the lower to middle 20s.
Sunshine returns on Sunday with highs in the 40s. Warmer
temperatures in the 50s arrive this coming week along with periods
of rain between Monday night and Wednesday.


Issued at 1044 AM EDT Sat Mar 24 2018

Forecast generally on track at this point with no substantial

Rather robust band of snow has finally edged into SW parts of
White county, mainly SW of a Wolcott to Monticello line. Little/no
snow being seen NW of this line. Upstream obs and trends suggest
that the band should remain in the same area over the next several
hours with some pockets of much higher returns and associated
heavier snow rates. Thus far temps have not moved much and are
just above freezing. Suspect that at least secondary roads are
having some issues, but hit and miss nature of heavier precip may
be allowing for at least some melting in between bursts.

Will keep advisory in effect and no changes to amounts at this
stage. As for the rest of the area, temperatures were struggling
to climb and could pose an issue in terms of reaching our
forecasted highs. Will monitor over the next couple of hours to
see if lowering of highs is needed.


.SHORT TERM...(Today and Tonight)
Issued at 428 AM EDT Sat Mar 24 2018

Strong and dry easterly low level flow doing its best to impede
approaching pcpn shield early this morning. Models in decent
agreement confining most pcpn to extreme southwest CWA and mainly
across southern White county. Latest hires model runs keep pcpn just
west of White county until afternoon but once saturation occurs,
impressive pcpn rates being indicated with convective signatures
within strongly forced but narrow frontal zone. Expecting a very wet
snow with ratios likely between 8:1 and 11:1.

Main concern or uncertainty at this point lies with bulk of pcpn now
expected during the afternoon with peak solar radiation through
cloud cover and sfc temps likely a few degrees above freezing. This
should lend to high compaction rates and would expect road
conditions to only become an issue within the stronger convective
snow bands where visibility will likely be reduced to quarter mile
or less as snow rates of an inch or two per hour become possible.
Impressive gradient in accumulations expected across White county
with only a dusting over northeast portions of county while
extreme southern areas near Tippecanoe border could reach 4 inches
with isolated 5-6 inches if convective elements come together.
Thus will continue advisory with only change being to extend
ending time to 00z/25th to account for slightly slower pcpn

Skies clear tonight but tight gradient remains between departing low
and stubborn high pressure. Lows will again drop into the lower
and mid 20s but with winds staying up have only lowered temps a
few degrees over fresh snowpack in the far southwest.


.LONG TERM...(Sunday through Friday)
Issued at 428 AM EDT Sat Mar 24 2018

Most of long term period still looks to be dominated by temperatures
near to slightly above normal and several periods of rain. Cooler
temperatures do return toward end of period.

Jet energy expected to carve out large scale upper trough over the
western CONUS early next week with upper low development in the 4
corners region. Deep moisture transport into the Midwest expected
with combo of Pacific mid level moisture and low level GOMEX and
Atlantic contribution. Slow moving cold front and several short
waves embedded in mid level flow will bring periods of rain to the
area from Monday night through Wednesday. Pointless to try and
pin down details of where localized heavier rain will fall with
upper energy well west over Pacific and not sampled well.
Climatology does suggest locally heavy rains possible with these
setups along with a large swath of moderate rainfall likely
producing upwards of an inch. Again location too uncertain at this
projection time with so many unknown variables. Did add some
slight chances for Thunder Monday night into Tuesday given
combination of kinematics and thermodynamics.

Will begin to see temperatures trend back to below normal by late
week and early next weekend as medium range models in surprisingly
good agreement with a clipper type system bringing another cold
airmass out of Canada.


.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 652 AM EDT Sat Mar 24 2018

The winter weather system will track south of the terminals during
this TAF period. Winds will become east and increase as the
pressure gradient tightens, and then should back this evening. A
very dry northeast to east flow will help prevent the development
of low clouds and help keep conditions VFR.


IN...Winter Weather Advisory until 5 PM EDT this afternoon for INZ020.

LM...Small Craft Advisory until noon EDT Sunday for LMZ043-046.



SHORT TERM...Lashley
LONG TERM...Lashley

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