Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 291106
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
706 AM EDT Fri Mar 29 2024

.KEY MESSAGES...

- Multiple rounds of showers and thunderstorms expected tonight
  into early next week.

- Heavy rain and non-zero chances for strong to locally severe
  storms exists Sunday afternoon through Monday night.

- Large variations in above normal temperatures expected through
  most of the period, before trending colder.

&&

.DISCUSSION...
Issued at 502 AM EDT Fri Mar 29 2024

Through Saturday night.

Ridging from the north will briefly take hold today, leading to
a good deal of sunshine and warmer temperatures. The focus then
shifts to the northward return of the warm front and a much
stronger surge of theta-e moisture into central/northern
Indiana as 40 kt LLJ noses in with increasing lift along and
north of the front. Arrival of showers has been slowed slightly
this evening, but a rapid uptick in coverage should commence
after 3Z and focus in the 6-12Z Sat time frame. Some elevated
instability will be edge in, but the greatest focus will remain
well west of the area. Will therefore maintain the mention of
thunder. Models still varying on how far north the boundary
works and final layout of greatest QPF potential. Most signals
still point towards our forecast area being lined up for the
best chance of 0.5-0.75" of rain, but some hints that this could
push further north. WPC QPF continues to wobble north and south
with each run and at this point will just ride with it. Next
challenge is how fast the rain departs on Saturday and is there
any redevelopment on the cold front. ECMWF has been the only
model to stay on the much slower side of the low tracking east,
with higher pops suggested well through the morning then
tapering in the afternoon. Still skeptical on this lone solution
being what occurs, but after collaboration with surrounding
offices have kept higher pops east in the morning then taper off
in the afternoon (limited to far SE). A large temperature
gradient is likely Saturday depending on final outcome of
precip, cloud cover and location of the warm front.

Sunday through Monday night.

The deep SW states trough will begin work east through this
period, with northern stream energy coming into the picture. The
frontal boundary that will reside south of the area will work
back north somewhat and then become stationary as a series of
disturbances rich in moisture, translate across the area.
Signals seem to suggest an area from northern IL SE across the
southern third to half of our forecast area and points SE lining
up for the best chance for rounds of showers and thunderstorms,
with localized QPF totals in the 1 to maybe 3 inch range. A non
zero threat for elevated strong to locally severe storms exists
Sunday night as nose of a strong EML and associated steep lapse
rates allows stronger storms to possibly produce hail. SPC DY3
outlook as placed areas along/S of US-30 in a marginal risk.
This could easily shift north or south in the coming days so we
will need to monitor trends. Stronger wave arrives late Mon
into Monday night when the greatest risk for heavy rain and
maybe severe weather could materialize as much better dynamics
arrive. Have left rather broadbrushed pops through this entire
period, but quite likely adjustments will occur as we get closer
to each event.

Tuesday through Thursday.

The northern and southern stream systems will be undergoing
phasing around of this period, with an surge of colder air
arriving and, sadly, at least a window for some snow (including
a period of lake effect). Way too much going on before this so
limited focus, but yet another element to sort out.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 659 AM EDT Fri Mar 29 2024

Predominantly VFR to MVFR conditions expected at the TAF sites
this period, with possible dips to IFR after 9z tonight
(especially at KSBN). Today will be dry with mainly increasing
clouds as the next system approaches the area. A warm front will
lift in tonight and bring rain and chances for thunderstorms
after 6z, which is when most of the guidance suggests MVFR
ceilings and visibilities. The best chance for IFR
ceilings/visibilities at both sites will be after 9z, and have a
prob30 to account for this with chances for thunderstorms. Rain
will continue through the late morning hours just beyond the
current TAF period, tapering off through the day Saturday.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.

&&

$$

DISCUSSION...Fisher
AVIATION...MCD


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