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000
FXUS63 KIND 271405
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1005 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.

&&

.FORECAST UPDATE...
Issued at 1005 AM EDT Sat Apr 27 2024

Radar distance speed tool was showing scattered convection zipping
along northeast around 50 mph from the upper Wabash Valley to the
Metro. Meanwhile, LAPS data was showing very weak instability with
SBCAPEs to less than 100 J/kg. ENTNL lightning data was not showing
any lightning strikes nearby at this time, however with CAPEs
increasing to 500 J/kg or more this afternoon due in part to drying
mid levels, should see some strikes in any convection. With the warm
front northeast of the area, there is not a lot of forcing, but any
impulse in the fast southwest zonal flow could provide enough for at
least isolated to scattered activity.

With deep shear to 40 knots combined with the instability, would not
rule out a strong or marginally severe thunderstorm this afternoon,
mainly over the upper Wabash Valley.

Breezy south and southwest winds and a few breaks in the overcast
will usher in very warm temperatures with afternoon highs expected
to reach the upper 70s and lower 80s.

&&

.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 (12Z TAF Issuance)...
Issued at 632 AM EDT Sat Apr 27 2024

Impacts:

- Mainly VFR conditions are expected

- Isolated RA/TSRA possible through TAF period, low confidence
overall through the period for specific timing/location.

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 aloft across Indiana. HRRR suggests periodic light showers
developing and diminishing through the day across Central Indiana.
Little in the way of organized forcing appears to be in play today.

Other than diurnal heating and the quick flow aloft, confidence
remains low for specific timing and location of any showers. Thus
have used a broad period of VCSH through the day to account for
precip chances for now.


&&

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

$$

UPDATE...MK
SHORT TERM...Puma
LONG TERM...KF
AVIATION...Puma