656
fxus63 kiwx 161756
afdiwx
area forecast discussion
national weather service northern indiana
156 pm edt sat may 16 2026
.key messages...
- 20% to 30% chance of an isolated thunderstorm prior to
sunset.
- very warm through at least tuesday with frequent chances for
showers and thunderstorms.
- thunderstorms may produce heavy rainfall and damaging wind
gusts, primarily on monday and tuesday.
&&
.discussion...
issued at 144 pm edt sat may 16 2026
this morning`s showers and thunderstorms have shifted east and skies
have cleared nicely as of midday. a narrow area of cumulus is noted
along the us 30 corridor, perhaps an indicator of an outflow
boundary. upper-level support for any afternoon or evening
thunderstorms is generally non existent, with 500 mb and 850 mb
jets located well to our north and southwest, respectively. thus,
despite surface cape swelling toward 1,500 j/kg this afternoon, the
modest trigger of a lingering outflow boundary leaves much to
be desired for renewed storm chances. can`t completely rule out
an isolated storm before sunset (20-30% chance) but overall,
not impressed and have coordinated with spc to reduce the extent
of the marginal severe weather risk today.
tonight, organized convection is expected over mo, ia, and
eventually into il. like yesterday, how this evolves offers
uncertainty. however, using the same synoptic methodology as
yesterday, the overnight period appears to be primarily dry.
toward sunrise, 500mb flow improves over il and could be a
forcing mechanism to sustain any ongoing convection there. yet,
despite the synoptic forcing, instability values of only 500
j/kg will be a limiting factor while shear improves to 30
knots.
a warm front, currently running east/west through lafayette, lifts
north early sunday morning as well, but given the dearth of
instability, high resolution guidance does little in terms of any
convection along the front. thus, have maintained only a 20% chance
of showers and thunderstorms to blend with neighbors. sunday
appears primarily dry and warm.
monday and tuesday remain murky but feature favorable severe
weather ingredients. the primary question is whether or not
convection fires monday afternoon from a prefrontal trough that
lifts in. should this trough become the focus for severe storms,
damaging wind gusts appear to be the primary hazard via steep
low- level lapse rates. afternoon storms would then squash the
overnight severe risk. the slow-moving cold front creeps through
our area tuesday serving as a continued focus for severe
storms. however, plenty of cloud debris is expected throughout
the day owing to any preceding convection. this will limit
instability values. heavy rain rates of at least 1" per hour
remain a concern early this week. overall, entering a period of
active weather that will require taking things one day at time
owing to mesoscale nuances.
cooler behind the front with highs some 20-degrees cooler; only in
the mid-60s wednesday and thursday. high pressure wednesday and
thursday becomes displaced over the eastern great lakes for next
weekend.
&&
.aviation /18z tafs through 18z sunday/...
issued at 152 pm edt sat may 16 2026
vfr to mvfr conditions expected at the terminals this period.
expect mvfr ceilings of 1500ft at kfwa this afternoon to
gradually improve to vfr with time. wsw winds shift more s-sw
through the period, with intermittent gusts up to around
23kts. most model guidance keeps any shower/t-storm activity to
be south of kfwa, but there are a couple models that generate it
further north along us 30-left out of the taf for now given very
low confidence.
&&
.iwx watches/warnings/advisories...
in...none.
oh...none.
mi...none.
marine...none.
&&
$$
discussion...brown
aviation...mcd