000
FXUS63 KIND 270713
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
313 AM EDT Sat Apr 27 2024

.KEY MESSAGES...

- Partly Sunny and warm with chances for showers today.

- Partly Cloudy and warm with chances for showers tonight.

- Warm through much of the period, particularly Sunday, when record
  highs may be threatened.

- Active weather, with multiple chances for showers and storms next
  week.

&&

.SHORT TERM (Today and tonight)...
Issued at 312 AM EDT Sat Apr 27 2024

Synopsis:

Surface analysis early this morning shows strong high pressure over
the east coast. Deep low pressure was found over IA and MN. This was
resulting in a moderate pressure gradient across Central Indiana
with southerly winds. Water vapor shows strong ridging in place over
the Appalachians and deep low pressure was found over the Dakotas
and Minnesota. A plume of tropical moisture was found between these
two systems, streaming high moisture air across the Ohio Valley and
Central Indiana. Radar mosaics show scattered showers and isolated
thunderstorms through the Wabash valley and the southern Mississippi
Valley. This was streaming north within the tropical plume. A very
warm and moist air mass remained across Central Indiana with dew
point temperatures in the middle 50s.

Today...

Little overall change is expected in the overall weather pattern
today and tonight. Models depict the strong ridging aloft to remain
east of Indiana. This will continue to steer any upper level
disturbances within the SW flow mainly west of our state, across the
middle Mississippi valley toward the western Great Lakes. Forecast
soundings today show convective temperatures in the lower 70s with a
column that appears quite moist. Pwats through the day remain around
1.3 inches but CAPE is limited and shallow. Still enough instability
will be present for isolated showers and perhaps a thunderstorm to
develop within the tropical air mass that will be in place. HRRR
shows very isolated convection development through the day, with the
best focus remaining over IL and the Wabash Valley. Again coverage
appears to be very limited. Thus with our limited forcing expected
today and only daytime heating to trigger showers, very low pops
will be used to cover this possibility, and mainly during the
afternoon hours with the best chances in place across the western
parts of the forecast area. However many dry and warm hours will
expected through the day. Given the ongoing warm air advection and
warm air mass in place highs in the upper 70s and even near 80 will
be possible today.


Tonight...

The predominate southwest flow aloft will remain in place overnight
as the models suggest the upper low over the upper midwest to push a
negatively tilted trough axis across IA toward WI. Much weaker and
poorly defined upper support was shown across IL and Indiana within
the warm and moist tropical flow. This is a low confidence signal.
However again, the tropical plume of moist air will remain across
the area tonight. Forecast soundings again show a nearly saturated
column overnight with pwats again over 1.2 inches. Thus similar to
the daytime hours, low chance pops will be needed, particularly
across the western areas, but many dry hours overnight will be
expected. Again with the warm and humid air mass in place across the
area overnight lows in the lower to middle 60s will be expected.

&&

.LONG TERM (Sunday through Friday)...
Issued at 312 AM EDT Sat Apr 27 2024

Large scale troughing will dominate over much  of the CONUS through
the long term, largely centered over the central plains. Multiple
waves will be moving through the trough, bringing multiple chances
for showers and thunderstorms. As the region will sit under largely
SW flow, along the leading edge of the trough, temperatures will be
well above normal with highs through the week expected from near 70
to the mid 80s and lows ranging from the 50s to 60s. Sunday will be
the warmest with highs up to the mid 80s, and while record temps are
not in the forecast at the moment, it`s only a few degrees shy so
still can`t rule out tying or breaking the daily record at Indy of
86 that day.

The first wave of the long term period will bring precipitation late
Sunday and should last through early Tuesday. A brief break in the
active weather is then expected before the next wave brings precip
Wednesday and then lasting through the end of the week. At this time
it is still looking as though the potential for severe weather will
stay off to our west, but can`t rule out that some favorable
parameters for stronger storms could reach central Indiana at times
from early to mid week. Models are still noisy for next week,
especially from mid week, on so confidence remains low.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 108 AM EDT Sat Apr 27 2024

Impacts:

- LLWS overnight, until 12Z.
- Showers expected through 08Z-09Z at LAF.
- Isolated RA/TSRA possible through TAF period, low confidence
overall through the period.

Discussion:

The TAF sites will remain within the warm sector through this period
as strong ridging remains aloft over the east coast allowing a
quick SW flow across Indiana. A quick moving short wave within this
flow will push an area of showers across the LAF area through 09Z.
Furthermore a strong LLJ is expected to push across northwest parts
of Indiana through the night. Thus have used a tempo group for
showers at LAf for the next 3 hours along with LLWS overnight.

Minimal forcing is suggested to pass through the day on Saturday.
HRRR suggests the development of isolated afternoon showers, but
confidence in any of these striking a specific TAf site at specific
time is low. Thus have used a VCSH window during max heating hours.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...Puma
LONG TERM...KF
AVIATION...Puma