266
FXUS63 KIND 281638
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1238 PM EDT Tue May 28 2024

.KEY MESSAGES...

- Scattered showers and at least a few storms are possible late in
  the day and early tonight. Highs will be in the 70s.

- Low precipitation chances linger into Wednesday across eastern
  portions of central IN

- Dry and Seasonable Thursday and Friday, Rain chances late Saturday
  into Sunday

&&

.FORECAST UPDATE...
Issued at 1011 AM EDT Tue May 28 2024

Only minor change to the forecast was to bump wind gusts up a bit as
diurnal mixing has been quite efficient this morning. Gusts at KIND
have already been upwards of 20kt. Expect breezy conditions to
continue as we progress into the afternoon, with readings as high as
25kt possible in a few places. Otherwise, forecast remains on track.

&&

.SHORT TERM (Today and tonight)...
Issued at 255 AM EDT Tue May 28 2024

Broad upper troughing will remain over the region today with a few
embedded shortwaves traversing the region. Expect mostly quiet
conditions through mid-afternoon as the first few upper level
impulses should remain north of the area. Rain chances then begin to
increase late this afternoon into the evening when another embedded
shortwave and attendant surface wave move in. The best chance for
rain will be north of I-70 where stronger forcing should be in place
with lower chances further south. Weak cold air advection and
increasing clouds late will help keep temperatures in the 70s again.

Subtle moisture return and daytime heating will likely
provide sufficient instability for at least a few storms. In
addition, steep low-level lapse rates suggest gusty winds are
possible in any heavier showers or storms. Precipitation should
continue into the early overnight hours before the system begins to
move east late. Low POPs linger through the overnight over far E/NE
counties as broad cyclonic flow from the surface low could keep
isolated showers around. A cold front associated with the surface
wave is expected to move through tonight leading to slightly cooler
lows in the low-mid 50s.

&&

.LONG TERM (Wednesday through Monday)...
Issued at 255 AM EDT Tue May 28 2024

As a deep troughing progress slowly eastward into New England the
next few days, two embedded shortwaves will influence Indiana`s
weather. One will pass through Wednesday and the other on Thursday.
Neither will have a substantial impact on temperatures but the MSLP
pattern will support northerly wind direction and temperatures that
are 5-7 degrees below normal with low humidity.

An accompanying lobe of increased moisture through a deep layer
should be enough when combined with diurnal heating for a few
convective showers and a low probability of a few lightning strikes.
Coverage should be limited and this should impact mainly the
northeast third of central Indiana.

Mid-upper ridging will start building to our west Thursday and
should nudge our temperatures up to near normal for late May by
Friday as the ridge axis crosses Indiana. A weak shortwave is shown
in most models crossing Saturday with a narrow ribbon of modified
moisture and weak instability, sufficient for low-mid range
probabilities of precipitation. Ensembles are all clustered around
light precipitation amounts, generally a quarter inch or less with
just a few outliers up to around an inch.

Chaos in the ensemble suite grows Sunday into early next week. Most
models show the larger scale pattern trending toward broad low-
amplitude ridging and positive height anomalies, bringing a warmer
pattern. The next somewhat organized precipitation event appears to
be late Monday, but smaller scale details are unclear. GEFS-weighted
clusters favor more troughing than EPS-weighted clusters and more
than just one frontal convective scenario. Will refine details later
this week.

Days 8-14: Multi-model ensemble mean shows a ridge west / trough
east pattern developing during this period. Some hold the ridge
further west and linger troughing longer, and some are more
progressive. Given the sensitivity of temperature to these pattern
differences we cannot say above or below normal with any degree of
confidence. This pattern would slightly favor drier than normal
conditions.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1238 PM EDT Tue May 28 2024

Impacts:

- Low probability showers and thundershowers between 22Z and 04Z.
- Gusty winds and temporary MVFR conditions possible in
  showers/storms.
- WNW wind gusts to 20-25kt possible today and tomorrow.
- Period of MVFR ceilings possible early Wed morning.

Discussion:

VFR conditions should persist through this afternoon. A weak storm
system diving down from the northwest may induce a few showers or
thundershowers towards the evening. These look to arrive somewhere
between 22Z and 04Z. Showers/storms will be fast-moving and will not
persist in any one location for a prolonged period of time. Brief
MVFR conditions along with gusty winds are possible with these.

Ambient surface winds will be out of the west-northwest between 10-
15kt with gusts 20-25kt. Winds decrease a bit overnight as the
boundary layer stabilizes but should pick up again Wednesday
afternoon.

A brief period of MVFR ceilings are possible Wed morning as the
center of the weak storm system swings by. These clouds should
diminish as the day progresses, due to boundary layer mixing and the
system itself departing eastward.

&&

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

&&

$$

UPDATE...Eckhoff
SHORT TERM...Melo
LONG TERM...BRB
AVIATION...Eckhoff