Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 220602

Area Forecast Discussion
National Weather Service Northern Indiana
202 AM EDT Sat Apr 22 2017

Issued at 159 AM EDT Sat Apr 22 2017

Skies will gradually clear from the northwest today as a ridge of
high pressure builds into the region. Highs will be in the 50s.
Mostly clear and cold conditions will favor some frost tonight.
with lows from 35 to 38. Sunny and warmer conditions are expected
Sunday with highs from 65 to 70.


.SHORT TERM...(This Evening through Saturday)
Issued at 247 PM EDT Fri Apr 21 2017

Short term concerns limited to frost threat later tonight across
mainly northern parts of the area.

Clouds have remained across much of the forecast area in various
stages. Lower clouds off Lk Michigan advecting into NW parts of
the area with high clouds and diurnal cu away from the lake.
Models vary on handling of inversion tonight and amount of trapped
moisture, resulting in a tricky forecast for frost potential.
Have slowed clearing down somewhat across the area considering
upstream trends, but do think at least partial clearing is
possible. Winds will decrease but still remain in the 4 to 8 mph
range, right at critical levels for ideal frost development. Have
opted to hold off on any frost mention or headlines tonight given
above noted concerns. Not an easy decision with many trees and
plants already budding. Lows in the mid 30 to around 40 still
expected so can`t rule out pockets of frost if clearing and full
decoupling occurs.

If not already clear, skies will clear out through the day from
north to south as strong ridging works in north of the area. Highs
will end up warmer than today, likely reaching into the middle to
possibly upper 50s.


.LONG TERM...(Saturday Night through Friday)
Issued at 247 PM EDT Fri Apr 21 2017

Frost potential front and center at the start of the period across
northern portions as clear skies and light winds should allow for
at least patchy frost. Have introduced mention in the grids but
holding on headlines as ridge axis to remain north of the area
which might keep more widespread frost from occurring.

Temperatures will continue to moderate with a return to near or
above normal levels starting Sunday. RH values may drop to 30% or
less in many areas with the dry airmass allowing for rapid drying
of fine fuels. Winds will remain low enough to minimize any
threat for fire issues.

Rain chances will increase Tues into Weds as longwave trough digs
to the west allowing increasing moisture and development of
several areas of low pressure moving along sfc boundary. GFS/EC
vary on timing and location of key features, resulting in high
confidence of rain occurring at some point but low confidence on
exactly when. Whenever the front finally makes it through temps
will cool back off somewhat, but indications still leaning towards
even deeper trough digging into the west at the end of the period
and stronger low level response (MEX bringing 80 degrees by
Friday. No major changes in later periods.


.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 153 AM EDT Sat Apr 22 2017

A ridge of high pressure will keep a cool and dry northeast flow
over northern Indiana through the TAF period with unrestricted
ceilings and visibilities.


LM...Small Craft Advisory until 11 AM EDT this morning for LMZ043-046.



LONG TERM...Fisher

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