825
FXUS63 KIWX 071800
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
200 PM EDT Sun Jul 7 2024

.KEY MESSAGES...

- Leaning dry between today and Monday, although a shower cannot
  be ruled out west of IN-15 this afternoon.

- Chances for showers and thunderstorms increase later Monday
  into Tuesday, especially west of I-69.

- Remnants of TC Beryl could bring rain and storms to parts of
  the area between later Tuesday and early Thursday with
  moderate to heavy rain being a possibility.

- Temperatures through this forecast period are right around
  seasonable. Monday looks to be the warmest with highs south
  of US-24 having a chance to hit 90 degrees.

&&

.UPDATE...
Issued at 1144 AM EDT Sun Jul 7 2024

No significant changes anticipated to the forecast for remainder
in the near term. Cu field has started to sprout up over the
past hour as convective temperatures around 80 degrees/lower 80s
have been reached. Relative warmth above low level mixed layer
should limit vertical extent of these clouds for most of the
area. The potential of an isolated shower appears to be limited
to the far northwest where slight cooler mid level profiles
should allow some modest surface based CAPES around 500 J/kg
this afternoon. Forcing is somewhat nebulous with better
mid/upper level forcing hanging back across eastern Iowa into
northern Illinois. Inherited slight chance PoPs still seem
reasonable for this scenario. Limited shear and instability
should result in any isolated stronger cores across northwest
Indiana to be limited in duration this afternoon/evening with
parameters not supporting organized convection.

&&

.DISCUSSION...
Issued at 322 AM EDT Sun Jul 7 2024

The day starts off with dry weather with dew points in the low 60s,
but the surface high pressure system will saunter off to our east
later today and that allows for increases in low level theta-e and
wetter surface dew points. Surface dew points will have crept back
into the mid 60s by day`s end today as a result of the return flow
out of the southwest. The better instability axis is west of IN-15,
where 500 to 1000 J/kg of MUCAPE reside. A lack of stronger forcing
is expected to keep most shower/storm activity at bay across the
area, but cannot completely rule out something west of IN-15 during
the afternoon. Will have slight chance PoPs, but these would not be
severe with shear limited to less than 30 kts.

On Monday, the area is on the eastern side of the trough in the
Northern Plains, but much of the forcing is to our west. As such,
despite some instability, it`ll be hard to get any obvious
convection to set off. Will have slight and low end chance PoPs west
of I-69 to indicate the potential for something to form with the
highest chance during the overnight hours into early Tuesday.
Instability will be similar, if not slightly higher than today with
between 500 and 1000 J/kg of MUCAPE, and shear will be marginally
conducive to sustaining stronger storms with pockets of 30 kts
especially west of IN-15.

As we head into the Tuesday through Thursday time period, the
remnants of Beryl will be the main focus. Models have trended
northward the last couple of runs and PoPs reflect that change. The
GFS/NAM appear to be quickest bringing the remnants up this way
while the ECMWF/GEM models are on the slower side with this system.
As we head into Wednesday, the ECMWF is between the GFS/GEM extremes
of carrying the center through the US-24 corridor through Wednesday
night. Either way, moisture within the column is increased with sfc
dew points sufficiently above 70 degrees and 850 mb dew points above
10C. Shear looks to be available underneath the remnants, but we`ll
have to see if a warm sector sets up to see if instability will be
available. The 1z NBM run has a 45% chance for 0.5" of QPF over
the previous 24 hrs ending 8pm Wednesday through the US-24
corridor. Given the spread on timing, track, and QPF, this would
indicate moderate to potentially heavy rain could occur with
this. WPC`s ERO was also ticked up to a slight chance for this
time period.

 The remnants of Beryl are currently forecast to move out
the area by Thursday, but energy within the trough carrying Beryl
out may also cause additional pop storms during the afternoons on
Friday and Saturday. Have indicated this with just slight chance
PoPs for now given the uncertainty.  Temperatures look to stay
around normal to slightly above normal from Monday through Friday.
The best chance for above normal temperatures look to be on Monday
as 90 degrees will be possible south of US-24. Times of clouds and
higher dew points likely restricting the upper limits that they
could otherwise reach.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 133 PM EDT Sun Jul 7 2024

Weak upper level energy was sustaining convective activity over
northern IL. This activity should remain northwest of SBN;
however, the bigger story in the tropical moisture plume
reaching the area early Monday. Showers and storms and
associated lower ceilings and visibilities will lag the arrival
of the tropical air until well after the end of the TAF period.

&&

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

&&

$$

UPDATE...Marsili
DISCUSSION...Roller
AVIATION...AGD/Skipper