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000
FXUS63 KIWX 241515
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
1115 AM EDT Wed Apr 24 2024

.KEY MESSAGES...

- Frost and freeze conditions possible tonight into early
  Thursday morning.

- Much warmer this weekend with periods of rain and a few
  thunderstorms possible.

&&

.UPDATE...
Issued at 1107 AM EDT Wed Apr 24 2024

Stratus persisting across the area, extending north into central
Lower Michigan. Trends have been for this to sink slowly south
as northerly flow is allowing lower dewpoints and better mixing
of clouds. HRRR low cloud field seems to have a decent handle on
the current cloud deck with the clouds likely to persist across
the area the rest of the afternoon, but starting to thin or
break up near/after 00Z and then expand south from there. It
does indicate that the clouds may stall across SW and SE areas
much of the night that could impact how far temps fall tonight
as well as how widespread frost will end up.

Coordination with surrounding offices not already under a
Freeze Warning has lead to evaluating trends into early
afternoon before making a decision. There is a good likihood
that much of the forecast area will need at least a Frost
Advisory but where to draw the line on solid below freezing
temps (and dewpoints in the low 20s) remains in question. Those
with sensitive plants should plan to take the necessary
precautions regardless of what type of headline may (or may not)
be issued.

&&

.DISCUSSION...
Issued at 325 AM EDT Wed Apr 24 2024

Rain associated with departing trough has finally fully exited the
area with dry conditions expected for the rest of the day. Strong
CAA will continue through the morning, pushing 850mb temps near -5C.
This will support ample stratocu through the day with afternoon
highs likely struggling to get above 50F. Have lowered max temp
forecast to be more in line with cooler raw guidance. Main story in
the short term will be potential frost/freeze tonight. As previously
mentioned though, clouds will be a concern. Some guidance suggests
stratocu will persist into the overnight hours while another (highly-
sheared) shortwave brings some increasing high clouds early Thu
morning. This does lead to some uncertainty but bulk of latest
guidance still indicates lows well below freezing in our NE half and
near/slightly above freezing in our SW. Dry air advection should
provide some clearing during the overnight hours before high clouds
arrive late. This coupled with light winds and chilly airmass
supports lows around freezing. Will hold off on any upgrades for now
though and let day shift make final call on where exactly to draw
freeze warnings/frost advisories.

Pleasant weather anticipated on Thu with highs climbing to around
60F under nearly full sun and light ESE flow. Lows Thu night will be
5-10 degrees warmer as surface high drifts east and SE gradient flow
increases (along with increasing clouds by early Fri AM).

Long term characterized by an extended period of deep S/SW flow and
a pair of upper lows ejecting from the southwest CONUS to the upper
Great Lakes. This leads to sharply warmer conditions with several
rounds of showers and storms likely. The first chance of rain is
associated with the initial warm front late Fri. Moisture return and
associated instability are not fantastic and best forcing remains to
our NW. Rain and a few embedded (non-severe) thunderstorms are
likely late Fri afternoon into Fri night with this initial theta-e
surge. Maintained NBM low chance PoP`s through the weekend (highest
NW zones) but much of the weekend could remain dry for many
locations as the primary baroclinic zone remains just to our west.
Cold front associated with the second upper low will not arrive in
our area until Sun night/Mon with our next good chance of widespread
rain/isolated thunderstorms. Again best forcing passes well to our
NW and current timing is not ideal for strong convection but still
plenty of time for changes this far out. After highs near 80F over
the weekend, temps drop slightly for the middle of next week but
remain above average for late April.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 547 AM EDT Wed Apr 24 2024

A cold front had moved southeast of FWA. Post frontal clouds
were spreading into the area and should persist for several
hours until subsidence with clearing is able to work its way
into northern Indiana. Otherwise, skies should eventually
scatter out later today with VFR conditions.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Freeze Watch from late tonight through Thursday morning for
     INZ005>009-018.
OH...Freeze Watch from late tonight through Thursday morning for
     OHZ001-002-004-005-015-016-024-025.
MI...Freeze Watch from late tonight through Thursday morning for
     MIZ078>081.
MARINE...Small Craft Advisory until 10 PM EDT this evening for LMZ043-
     046.

&&

$$

UPDATE...Fisher
DISCUSSION...AGD
AVIATION...Skipper