Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 171737

Area Forecast Discussion
National Weather Service Northern Indiana
1237 PM EST Fri Feb 17 2017

Issued at 240 AM EST Fri Feb 17 2017

A warm front will move northeast into the Great Lakes today
bringing an unseasonably warm airmass into our area. A weak cold
front will move into the area Saturday, but any cooling associated
with this feature should be limited to areas near Lake Michigan.
High pressure will move across the area Sunday and Monday
providing fair weather and continued unseasonably warm
temperatures. A weak frontal boundary will move into our area
Tuesday and become stationary through Thursday, bringing a low
chance of showers in this time frame, though, temperatures should
remain much above normal.


Issued at 1055 AM EST Fri Feb 17 2017

Warm front will continue to slowly progress across northeast half
of the area through this afternoon. South of the warm front
temperatures have quickly pushed into the mid-upper 40s across
southern/western portions of the forecast area this morning.
Previously forecasted highs on the warm side of guidance still
seem reasonable and no major changes made at this time as 12Z
RAOBS and regional AMDAR soundings support temps to this magnitude
despite very shallow mixing. Area of slightly lesser confidence
for highs today is across the northeast third where timing of warm
frontal progression and even more questionable mixing may limit
temps to the lower 50s. Record highs for the date at Fort Wayne
and South Bend are 61 and 59 respectively which may be threatened
this afternoon. Updated zones will be sent by noon, mainly to
freshen up morning sky cover trends.


.SHORT TERM...(Today and Tonight)
Issued at 240 AM EST Fri Feb 17 2017

Warm front over central IN early this morning expected to lift ne
across our area today followed by a dry/warm airmass. Rather
large differences among mos guidance highs for today. Given dry
low levels upstream on ILX 00z sounding, expect GFS overdone on
low level moisture and potential low cloud development along the
warm front over our cwa this morning, lingering in the east into
the aftn. Thus, with mostly sunny skies expected along with snow-
free ground, and decent swly gradient developing, especially
across the sw, prefer warmer 00z guidance for today with highs
ranging from the m50s ne to the m60s sw. These highs appear to be
in line with what occurred upstream across srn IA, central IL, and
nrn MO yday.

Skies should remain mainly clear tonight, though some cirrus
wrapping around an upr low movg ene from the srn plains will move
over our cwa late. Swly gradient will cont mixing in low levels
tonight, as a wk cdfnt moves se across the upr grtlks, so again
leaned toward warmer guidance with lows in the lwr to middle 40s.


.LONG TERM...(Saturday through Thursday)
Issued at 240 AM EST Fri Feb 17 2017

Shrtwv and associated wk cdfnt will move across the grtlks Sat as a
shearing out upr low moves into KY. Warm start to the day should
offset wk caa and only partial sunshine yielding highs similar to
today, though a little cooler nw as winds shift to off the lake.

Another strong upr level ridge will build east from the plains
across the Midwest Sunday and Monday contg dry conditions with much
above normal temps. Wkng shrtwv/cdfnt lifting over this ridge
will bring a chc showers Tue but no sgfnt change to the much above
normal temps. This wk cdfnt expected to stall over the area
Wed/Thu as a strong low pressure system develops over the central
Plains. Wk forcing and limited moisture suggest only a low chance
of showers in this time frame as this front lingers in the area.
Temps should remain very mild for Feb, especially across srn
portions of the cwa which should stay south of the stalled frontal


.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1226 PM EST Fri Feb 17 2017

Quiet aviation weather conditions for this forecast period. Warm
front has cleared terminals with south-southwest winds of 10 to 15
knots expected to prevail through this period. Some increase in
high clouds is expected by Saturday morning in response to slow
eastward progression of cut-off PV anomaly across the Southern
Plains, but VFR conditions should prevail. Sfc trough tracking
across the Great Lakes tonight should be accompanied by downstream
modest low level jet across northern Indiana, and have maintained
LLWS mention tonight from previous forecast.





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