093
FXUS63 KIWX 030724
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
324 AM EDT Mon Jun 3 2024

.KEY MESSAGES...

- Primarily dry today with highs in the 80s. A low chance of
  isolated storms tonight.

- Widespread showers and storms Tuesday night through
  Wednesday.

- Remaining warm through Wednesday before cooler air settles in
  for the rest of the week.

&&

.DISCUSSION...
Issued at 319 AM EDT Mon Jun 3 2024

Fog has developed this morning, primarily north of US 30 and is
dense in spots toward the Michigan line. This as high pressure
is established over Indiana with ample soil moisture from
Saturday and Saturday night`s rainfall. Since the calendar
reads, "June", this fog should mix out rather quickly after
sunrise.

Aloft, a ridge axis is noted over Illinois and Indiana on water
vapor. To the west, thunderstorms are decaying as they approach Iowa
early this morning associated with an area of low pressure over
southern South Dakota. This low lifts northeast through the day as
weak troughing over the Northern Plains encounters the aformentioned
ridge. HREF guidance indicated 500mb flow not only lifts northeast
but weakens through the day. 850-mb flow behaves similarly. Not much
to speak of at the surface for a forcing mechanism either. Overall,
a very poor case for showers and thunderstorms late today and into
the overnight. As a result, leaning on high-resolution guidance,
I`ve restored the dry forecast during the day and significantly
limited the scope of POPs for tonight, favoring POPs for the Benton
Harbor and South Bend areas. This is a significant about-face when
compared to earlier forecasts; a byproduct of weak flow and drifting
convection.

Turning to Tuesday, a pair of short waves ripple into the area
working to break down the ridge whose axis is not over the
Appalachians. Tuesday likely begins dry (see preceding paragraph) but
as afternoon temperatures rise well into the 80s, showers and
thunderstorms will dot the area. Instability will be sufficient
while shear and lapse rates are lacking. Thus, pulse, non-severe
thunderstorms are favored.

Showers and thunderstorms become more widespread by Wednesday
morning as a deep trough aloft and cold front arrive. Strong cold
air advection is in place from Wednesday night through the end of
the week. This keeps high temperatures in the low-to-mid 70s. (the
in-house blend is still running warm with a 75th percentile forecast
Wednesday through Friday.) This trough aloft becomes cut off from
the jet stream focused across northern Canada, leaving it to swirl
over our heads for an undetermined length of time. Until it kicks
east, expect a chance of scattered showers day-to-day and below-
normal temperatures.


&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 132 AM EDT Mon Jun 3 2024

Clear skies, calm wind, and residual boundary layer moisture
will support the potential for fog early this morning. Several
area sites have already dropped below 1SM and expect
visibilities to drop at the terminals soon. While there is
reasonable agreement for fog in the guidance (particularly for
KFWA) confidence is not high as the moisture is very shallow and
visibilities have been variable at other sites so far tonight.
Enough support for 1/2SM fog at KFWA but lower confidence at
KSBN and will hold with 1SM for now. Otherwise VFR expected the
rest of the period. There is a very low chance for a shower or
storm at KSBN Monday evening but confidence is far too low to
mention in the TAF at this point.

&&

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

&&

$$

DISCUSSION...Brown
AVIATION...AGD