Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 281153

Area Forecast Discussion
National Weather Service Northern Indiana
653 AM EST Tue Feb 28 2017

Issued at 455 AM EST Tue Feb 28 2017

Showers and a few storms will will continue today before shower
and thunderstorm activity becomes more widespread tonight. Strong
to severe thunderstorms are possible tonight as a strong cold
front approaches. Highs will reach into the lower to middle 60s
this afternoon. It will turn colder Wednesday into Thursday
behind the front with chances for snow showers lingering into


.SHORT TERM...(Today and Tonight)
Issued at 455 AM EST Tue Feb 28 2017

Focus today primarily on overnight conditional severe risk. In
meantime burgeoning warm advection leaf continues to push eastward
into CWA and outpace well upstream MUCAPE reservoir of 500-750 j/kg
into central IL /northeast flank of much stronger/greater than 2000
j/kg over central OK. Rather meager instability for much of the day
and parcels likely to remain elevated until later this evening. As
such have mostly modest chance pops today with lesser TSRA mention.
Until later this evening as strong frontal wave lifts rapidly
northeast from northern MO this evening into west central lower
Michigan by 06 UTC. Fervent surface to 850 mb theta-e surge in
advance of this feature to provide sustenance to more significant to
late afternoon/evening MLCAPE axis /1000-2000 j/kg/ that develops
upstream over mid Mississippi Valley into Ozarks. Surge of 60F
dewpoints already into northeast KS more remarkable than last Friday
evenings largely low end to sub severe event. Progressive nature of
mid/upper level trof axis with impressive deep layer shear on order
of 50-70 kts should aid in storm organization into linear
segments/squall line through CWA most probable timing in 02-08 UTC
window. Dual low level jetlets per nam12 might suggest two lines
with far southeast CWA relegated to a significantly later convective
episode. As 100m/12 hour height fall centroid hastens to intercept
this line/collocation of divergent exit region as 140-150 kt 3H jet
axis pushes into Lower Ohio Valley suspect uptick in dynamics to aid
in maintaining at least a low to near severe wind risk well after
midnight/early morning hours. Added several degrees over blended
highs today with dry episodes and strong low level warm air
advection to continue/offset largely overcast day. Additionally have
sided warmer overnight with lows closer to coolest hourlies/save for
far northwest where southeast advancing cold front will begin to
make inroads.


.LONG TERM...(Wednesday through Monday)
Issued at 455 AM EST Tue Feb 28 2017

Progressive system aloft will pass through the lakes Wed as sfc cold
front sweeps east. Mild morning temps to fall as strong cold air
advection wraps in behind with rain mixing/changing to snow nw-se
with time in trailing deformation zone/wrapped moisture plume.
Continued agreement with substantive clipper to follow Thursday
with widespread light snow chances followed by increase in lake
effect snow within decent lake enhanced thermodynamic profile and
full lake axis fetch. Thereafter more noise seen in model trends
than before and largely cut blended pops until more apparently
favorable/agreed upon chances late Sunday into Monday. Otherwise
building heights/persistent low level warm air advection to bring
quick rebound from Fridays few degrees below normal back to well
above normal for the remainder of the weekend.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 648 AM EST Tue Feb 28 2017

An initial round of showers and a few storms will move out of the
area early this morning, followed by a break in most of the
showers during the day before much stronger storms move into the
area tonight ahead of a strong cold front. Winds should increase
this evening with the chance for strong to possibly severe storms
to move into the area in the 02Z to 09Z period.


LM...Small Craft Advisory until 5 AM EST Wednesday for LMZ043-046.



LONG TERM...Murphy

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