479
FXUS63 KIWX 122227
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
627 PM EDT Sun May 12 2024

.KEY MESSAGES...

- Very low chance of showers tonight along the Indiana Michigan
  state line.

- Dry to start Monday, but a chance of later afternoon showers
  and thunderstorms.

- Drying out Wednesday and Thursday.

&&

.DISCUSSION...
Issued at 205 PM EDT Sun May 12 2024

One trough tracking through Quebec and a second trough swirling over
western Kansas are the two features to watch in the coming 48
hours. A cold front is noted across the far Northern Plains,
nosing into the western Great Lakes, associated with the
Canadian trough. This will continue its trek southeast and
bring increasing high clouds this evening and a very low chance
of a shower for IN-MI border residents. Otherwise, dry tonight
with unseasonably mild lows in the upper-50s.

By Monday morning, what was the western Kansas trough is now
approaching the Mississippi River, spreading clouds overhead.
Monday looks primarily dry, but the late afternoon hours present
a chance for rain, primarily west of I-69. This is a result of
WAA and isentropic ascent amongst the buckling jet stream.
However, robust convection is forecast to be ongoing across the
Gulf Coast states Monday, aided by a stout 500mb jet. Pattern
recognition dictates this has historically robbed poleward
moisture transport thus delaying the onset of rain. I`ve
attempted to be stingy with POPs prior to 21z (5pm EDT) Monday.

Instead, the best widespread push of showers and storms is Monday
night and Tuesday as the surface low moves through northern Indiana.
Storm total rainfall near 1 inch is likely, with some model guidance
members indicated up to 1.50" is possible. Seven-day observed
precipitation anomalies indicate streaks of above-normal
rainfall. These positive anomalies become more widespread with
14-day and 30- day periods. Therefore, flooding is not a
significant threat, but cannot be ruled out completely.

Drying out near sunrise Wednesday as the low moves over the Mid-
Atlantic. Dry on Thursday as well before a shortwave moves into the
Midwest Thursday night through Friday. Into next weekend, guidance
is starting to advertise a towering Southeast US ridge, perhaps
pushing our 850mb temperatures to 16-18C; toasty.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 625 PM EDT Sun May 12 2024

VFR ceilings and visibilities are likely to prevail throughout
the duration of the TAF cycle. Winds will remain elevated
overnight, with sporradic 15-20 kt gusts possible overnight and
into the day Monday. A surface low will lift through Indiana
late Monday and into Tuesday, and thus rain chances will need to
be introduced in later TAF forecasts (likely starting around
21Z Monday). Just beyond this TAF cycle, ceilings quickly drop
to MVFR amid rain and thunderstorms late Monday night.

&&

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

&&

$$

DISCUSSION...Brown
AVIATION...Johnson