Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 171046
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
646 AM EDT Sun Mar 17 2024

.KEY MESSAGES...

- A colder Sunday with scattered snow showers around during the
  day. Lake effect snow showers take over tonight with snow
  accumulation possible in Michigan by Monday morning.

- Dry and seasonable midweek. Temperatures below freezing at
  night will be possible during this stretch.

- Our next chance for precipitation is late week

&&

.DISCUSSION...
Issued at 304 AM EDT Sun Mar 17 2024

The vort max associated with an upper low pressure system continues
to shift eastward towards southeast Canada today. Meanwhile, another
vort max within the large upper trough from Canada into the Northern
CONUS traverses west to east across Lake MI and the strung out
vorticity associated with the upper trough crosses through the area
this evening. This sets up the area with breezy winds between 20 and
25 mph today with the lingering pressure/thermal gradient overhead.
These winds will be cold advecting behind yesterday`s cold front so
today`s highs will be 40s, which is a good 20 degrees cooler than
yesterday as yesterday`s positive 850 mb temperatures fall towards
-10C, reaching it by day`s end. There`s some low level dryness to
start the day and ceilings overnight were up near 5000ft when radar
returns depicted showers probably indicating more of a virga
situation. As a few instability troughs move through the area during
the day today, there could be a few lake enhanced snow showers in
that develop with the greatest chance for this occurring during the
afternoon, but think the antecedant dry air at least cuts into
resultant QPF totals and provides a ceiling for PoPs to chance at
most.

Then, heading into this evening and overnight, behind that strung
out area of vorticity, inversion heights rise to between 700 and 850
mb allowing for delta Ts between 20 and 25, which indicate a low end
lake enhanced event. Any accumulations struggle to occur on roads
after the recent warm spell and the expected lower QPF totals will
also cut into the magnitude of this event. The strongest of this
lake enhancement moves through after midnight tonight and continues
into Monday morning accumulating between an inch or 2 of snow between
 Berrien and St Joseph counties in Michigan. downwind from Lake
MI mainly on grassy areas. We did just have 60 degree
temperatures yesterday after all. After 15z Monday, the low
level wind convergence becomes more divergent with low level RH
dropping off and theta-e lapse rates becoming more positive
allowing precipitation to diminish. Additionally, warm advection
takes over as high pressure noses into the area.

For Tuesday, a clipper system passes by to the north invigorating
the pressure gradient and increasing wind gusts to between 25 and 35
mph. With these winds out of the southwest, we`ll be able to warm
back into the 40s and low 50s the area. Temperatures drop back into
the 40s, though, Wednesday and Thursday as we continue to stay in
the northern stream jet. This allows for a time period of below
freezing lows overnight during this period. An upper low
pressure system moves west to east across the Gulf States
cutting off any moisture that could arrive to the area keeping
us precipitation free.

At this point, the handling of that aforementioned upper low
diverges, but the pattern may become conducive for precipitation
between Thursday night and Friday as another shortwave in the
northern stream flow approaches the western Great Lakes.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 646 AM EDT Sun Mar 17 2024

Primarily VFR conditions anticipated through today although
brief flurries and MVFR ceilings may be possible as a shortwave
crosses the area. Better chances for LES and MVFR ceilings will
arrive at KSBN overnight as the flow veers slightly and colder
air filters south. Otherwise expect another breezy day today
with deep mixing.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory until 11 PM EDT Monday for LMZ043-046.

&&

$$

DISCUSSION...Roller
AVIATION...AGD


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