Area Forecast Discussion Issued by NWS Northern Indiana
000
FXUS63 KIWX 122320
AFDIWX
Area Forecast Discussion
National Weather Service Northern Indiana
720 PM EDT Fri Apr 12 2024
.KEY MESSAGES...
- Very warm Sunday through Wednesday with highs well into the
70s.
- There is a marginal risk of severe thunderstorms Sunday
afternoon toward the Indiana and Ohio state line.
&&
.DISCUSSION...
Issued at 248 PM EDT Fri Apr 12 2024
Wind gusts have just begun topping 40mph this afternoon, with Knox
recording a 43mph gust. RAP forecast guidance suggests the surface
low and low-level wind field may strengthen yet this evening.
Decreasing cloud cover can improve our mixing, but even so, upstream
observations are closer to 40mph than 45-50 mph. So, will somewhat
hesitantly let the wind advisory ride as-is. Rain showers have
sprouted nicely off the lake and in the vicinity of vort max as seen
on water vapor imagery. This diurnal activity will end around
sunset; same for the showers noted across Wisconsin as of this
writing.
Aside from a chance of thunderstorms Sunday, a beautiful weekend is
on deck. A swirling upper-level low is replaced by high pressure
centered over the Southeast US and a ridge aloft slowly builds.
Highs near 60 on Saturday (approaching 70 toward Monticello) give
way to widespread 70s Sunday. However, a low streaking through the
Great Lakes will send a weak cold front through in the afternoon.
This will result in plummeting temperatures lakeside as
northwesterly wind sets in. This cold front could be the focus for
isolated thunderstorms toward the IN-OH state line. Here,
instability is marginal (near 500-1,000 j/kg), but dew points in the
upper 50s and shear near 40-50 knots are appropriate for the
highlighted marginal risk. Forecast soundings show a cap near 5,000
ft; something the cold front might overcome. I`ll hold steady with
only a 20% chance or so due to very limited coverage on forecast
guidance.
This is a weak cold front indeed as high temperatures quickly
rebound Monday back into the 70s. This, as 500mb heights rise in
response to a deepening trough over the west. By midweek, a surface
low moves through the Midwest bringing more rainfall and a risk of
severe weather to Illinois and western Indiana. Forecast rainfall
ranges notably at this time.
In the wake of this low, a second is quickly on its heels to end the
week. This brings notably colder air to the region; a real bummer
following a week in the 70s.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 720 PM EDT Fri Apr 12 2024
Rain showers associated with a passing midlevel vort max and
very cold temps aloft will taper off within the next few hours.
No impacts to the terminals are expected with VFR conditions
persisting and light sprinkles at best. Winds will also continue
to diminish with the loss of daytime heating. Clear skies
anticipated on Saturday with a steady WNW wind (a few gusts of
20-25 kts possible, especially at KFWA).
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Wind Advisory until 8 PM EDT this evening for INZ005>009-014-
017-018-104-116-204-216.
OH...Wind Advisory until 8 PM EDT this evening for OHZ001-002-004-
005-015-016-024-025.
MI...Wind Advisory until 8 PM EDT this evening for MIZ078>081-177-
277.
MARINE...Small Craft Advisory until 5 AM EDT Saturday for LMZ043-046.
&&
$$
DISCUSSION...Brown
AVIATION...AGD