193
FXUS63 KIWX 092002
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
302 PM EST Sat Nov 9 2024

.KEY MESSAGES...

- Sprinkles or light rain will become more widespread overnight
  into Sunday morning.

- Drier conditions return for Monday and Tuesday before another
  system brings a chance for showers.

- Temperatures should be near or above normal through the period.

&&

.DISCUSSION...
Issued at 300 PM EST Sat Nov 9 2024

Feature of interest for the next 24 hours or so is a well defined
closed upper low in SW Nebraska that will move NE reaching central
WI by 18Z Sun. Increasing isentropic lift ahead of the warm front
was generating pockets of light rain and rain showers from SE Iowa
into NE Illinois. Initial returns having to work rather hard to
overcome a very dry layer as noted on 12Z KILX sounding, but are
occasionally reaching the ground as sprinkles or brief light rain,
which is barely measuring. The degree of lift and lowering CPDs
(Condensation Pressure Deficits) will increase after 00Z from SW to
NE with the most pronounced push happening between 6Z and 15Z Sun.
Mixing ratios of 8 G/KG and PWATS of 1.5" or greater, combined with
some fairly stout flow at times perpendicular to isentropic surfaces
point towards at least a window of numerous showers late tonight
into Sunday, with challenges being faster movement of the showers
and the overall system as well as degree/location of elevated
instability. Overnight, some models are suggesting pockets of higher
QPF, maybe in the 0.50" or more range where some of the stronger
convective elements possibly materialize. However, forecasted QPF
will not capture these finer details and more than likely most areas
will see closer to 0.25" to maybe 0.33". Regardless of how much, any
rainfall is welcome. A few rumbles of thunder cannot be ruled out
with showalter values dropping below zero by 9Z Sun in SW areas
spreading east and leaving by 14Z. Severe weather is not expected
despite favorable shear profiles.

A weak cold front (more of a subtle wind shift and lowering of
dewpoints) will occur from west to east during the afternoon,
bringing any precipitation to an end. Prior to the arrival of the
front, temperatures will likely climb into the 60s, but leave just
as quick as it arrives as modest CAA starts behind the front into
Sunday night and Monday. Another decent northern stream wave will
pass by to the north with its only contribution to our forecast
being another cold front dropping through late Monday into Monday
night to bring colder air that will send our temps to slightly below
normal levels (Highs Tuesday in the upr 40s to low 50s).

A strong upper low, located over the Gulf of Alaska will drop SE to
start the work week, with increasing upper level ridging commencing
for the area starting Tuesday. The low will initially open and
become more progressive, while attempting to phase with a weak upper
low over the Baja of California. Previous model runs suggested this
merger and also increasing upper level winds would cause the upper
trough to close off again, but 00Z and even 12Z Sat runs leaning
against that. This appears to be having some influence on the amount
of moisture to be advected in Wed into Wed night with PWATs more
subdued (maybe touching 1"). Conservative approach on pops remains
warranted for this period limiting to chc for now. In addition, the
wrap around precip that was suggested to linger Thu/Thu night looks
less impressive as well, but will maintain some slgt chc pops.

An elongated trough will set up from California to NE North Dakota
for the remainder of the period, with our region returning to a more
southerly flow and temperatures making a run well into the 50s and
probably near 60. Some pops have been populated by the model blends,
but given the stronger features will remain to the west and south,
suspect these will be removed over time.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1248 PM EST Sat Nov 9 2024

VFR conditions this afternoon and early evening will deteriorate
to predominantly MVFR/IFR conditions overnight into late Sunday
morning/early afternoon. LIFR conditions are possible at both
sites, especially after 9z. Rain will lift in (after 3-6z) ahead
of an occluding surface low, which as of 18z is centered over
KS. This low will lift northeastward through the period,
crossing through IA and into WI by Sunday afternoon. Rain will
be more of a steady nature through around 15-18z before the dry
slot moves in overhead, starting at KSBN closer to 15z and
moving into KFWA towards 18z. This will lead to more of a
showery/drizzle nature as upper level moisture is scoured out.
Ceilings may deteriorate as low as LIFR [400-500 feet] as
subsidence from the exiting surface high traps the influx of
low level moisture beneath the inversion. It will depend on how
quickly the moisture moves in before we get back into the
daytime hours Sunday-so confidence is more medium to low in 400
ft ceilings. Have prob30`s for now in this period as a heads up,
will add greater detail in next forecast.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory from 1 PM Sunday to 7 AM EST Tuesday for
     LMZ043.
     Small Craft Advisory from 1 PM Sunday to 1 AM EST Monday for
     LMZ046.

&&

$$

DISCUSSION...Fisher
AVIATION...MCD