998
FXUS63 KIWX 252320
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
720 PM EDT Fri Apr 25 2025

.KEY MESSAGES...

- Showers and thunderstorms are expected to continue into the
  late afternoon and early evening before dissipating. No severe
  weather is expected although some minor flooding/ponding may
  be possible in more urban areas.

- Cooler temperatures on Saturday in the 50s and low 60s will
  give way to the mid 30s to low 40s Saturday night. Frost will
  be possible in areas west of IN-31 and north of US-6.
  Temperatures trend warmer through Tuesday.

- Strong to Severe thunderstorms possible across the area
  Tuesday afternoon into early Wednesday morning. Still
  considerable uncertainty on the details at this time.

&&

.DISCUSSION...
Issued at 231 PM EDT Fri Apr 25 2025

Weaker vort maxes helped along by the upper jet to the north forces
a weak sfc low as it moves eastward today. Relatively weak moisture
transport from the south is generally out of the southwest draped
south of US-24 today. MUCAPE resides in the flow with the moisture
and relative mild temperatures through the column allow for the
chance for some embedded thunder especially where the better
convergence resides, but given the weak flow, severe weather will be
kept at a minimum. Could see some locally heavy rain this evening
before the rain shuts off.

Tonight, the sfc low shifts eastward and, as it does so, an upper
low deepens and stronger northwest winds come in on its backside for
late tonight/Saturday morning. Despite the cooler air arriving, the
excited winds are expected to keep fog at bay. Saturday AM lows will
dip into the low 40s for highs as the marine airmass comes in off
Lake MI. CAA is expected to continue on Saturday providing cooler
temps in the 50s to low 60s south and east, away from Lake MI. High
pressure follows on the backside of the developing upper low and
this is expected to keep the weekend dry, but we`ll be wattled
with the relative cool temps. Some frost is possible on Sunday
morning as temps dip into the mid 30s as high pressure moves
through, winds go light to calm and minimal cloud cover exists
to impede radiational cooling.

A warming trend from highs in the 50s on Saturday to highs in the
70s on Monday is helped along by the arrival of south winds on
Sunday and southwest winds on Monday. A warm front pushes through
Monday night setting up a cold front to push through Tuesday
evening. Monday looks to be on the dry side, but will continue to
feel more humid as dew points increase into the 50s and 60s by the
end of the day. This sets up Tuesday to have dew points rise into
the mid 60s out in front of the arriving front. As currently
depicted, anything that might form out in front of the front would
be forming in more boundary-parallel shear and may have a chance to
train. This would be the main cause of heavy rain if it was going to
be a hazard as storm motions appear to be quick and the MBE vectors
appear unfavorable for back building. Should instability be able to
form in front of the front and be unimpeded by cloud cover or the
like, boundary-perpendicular shear exists closer to the front and
may be able to get a few supercells to form. This would put all
hazards on the table with damaging wind and hail being the primary
threats, but a tornado cannot be ruled out. Of course, there`s also
the question of timing of the cold front and debris clouds left over
from the warm front that could completely derail this severe chance.

The front ends up draped west to east across the area on
Wednesday with a high pressure system to our north.
Showers/storms will be possible along or just south of the
baroclinic zone, which has model confluence on location in the
latest model runs. While a majority of the rain is forecast to
stay south, cannot completely rule out rain across our 1 to 2
tiers of counties depending on eventual front position. Rain
chances increase again towards the end of the week (probably
just Thursday) as a coupled jet scenario allows a developing low
to lift north out of the southern US. Friday into the weekend
leans dry again as another vort max drops into the area from
Canada.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 718 PM EDT Fri Apr 25 2025

VFR to start will rapidly dwindle into widespread IFR as post
cold frontal status blooms across the terminals this evening.
This will gradually erode/lift into Sat aftn. Otherwise quite
gusty nwrly winds expected to develop this evening as low level
cold advection ramps with gusts aoa 20kts.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory until 8 PM EDT Saturday for LMZ043-046.

&&

$$

DISCUSSION...Roller
AVIATION...T