339
FXUS63 KIWX 150746
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
246 AM EST Fri Nov 15 2024

.KEY MESSAGES...

- Patchy drizzle will dissipate this morning but cloudy skies
  will remain through Saturday with highs in the low/mid 50s.

- More rain and warmer conditions are expected Monday into Tuesday.

- Cooler conditions return by the end of next week with more
  precipitation possible but forecast confidence is very low.

&&

.DISCUSSION...
Issued at 245 AM EST Fri Nov 15 2024

Drizzle and low clouds currently holding strong over the area and
will likely continue to do so well into the morning. Hi-res model
soundings show a deep (4-5 kft) layer of very moist conditions below
a strong subsidence inversion. Hi-res models further indicate
continued weak omega in this moist layer well into the late morning
that suggests at least patchy, light drizzle during this time given
persistent cyclonic flow within the moist layer and added theta-e
flux from warm Lake MI.  Midlevel ridging/AVA does increase
substantially during this period but only acts to strengthen the
inversion and trapping the low level moisture. We don`t get any
meaningful dry air advection/veering winds in the lowest levels
until the afternoon. This will bring an end to the drizzle but
expect low stratus to persist through the day and probably into
tonight given lingering boundary layer moisture under strong
inversion. This keeps an effective lid on temps with highs only a
few degrees warmer than present values. Also raised lows several
degrees based on expected cloud cover with generally low 40s,
possibly even holding in mid 40s.

Similar conditions likely to start the day Sat but WAA begins to
ramp up late Sat and into Sun as high-amplitude ridge axis passes
east of our longitude. Increasing southerly flow *might* bring a
break in the clouds late in the day but there will also be
increasing high clouds associated with next approaching trough.
Expect highs to remain in the low/mid 50s. The primary midlevel
circulation lifts well NW of our area and we only get brushed with
some minor height falls/CVA Sun night. There is a decent theta-e
plume ahead of this trough that will probably be aided by Lake MI
but any measurable precip will likely remain north of our CWA until
Sun night as the decaying "cold" front passes.

This front washes out across our area and quickly lifts back north
as a warm front late Mon. This is the first stage of a notable
pattern shift expected next week as a series of Pacific troughs move
over the country and eventually form a large cutoff low somewhere in
our region late week. The first trough lifts NE Mon night and brings
our next chance of widespread light-moderate rain in very similar
fashion to previous two systems. But this system will be quickly
followed by a stronger/deeper upper low late Tue/Wed. There remains
considerable uncertainty with very important details regarding
timing, track, and evolution of this upper low as deterministic and
ensemble guidance are still offering wildly variable solutions. What
we can say is that there will be a period of very warm temperatures
to start the week that will eventually transition to colder temps at
the end of the week. With a potential upper low and still very warm
lake temps, lake effect precip is certainly a possibility.
However...precip types, amounts and timing are extremely uncertain
at this time range. It will likely be several more days before any
of those details can be nailed down.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1247 AM EST Fri Nov 15 2024

Patchy drizzle was occurring in the wake of the departing
surface low and extended well to the west over northeast IL. The
drizzle should end by mid morning as drier air continues to
spread over the area. Have kept IFR conditions out for now, but
a brief VSBY down to 2SM and 008 ceiling is possible past
daybreak. Otherwise, have conditions becoming VFR by 02Z.

&&

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

&&

$$

DISCUSSION...AGD
AVIATION...Skipper