526
FXUS63 KIWX 281731
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
131 PM EDT Tue May 28 2024

.KEY MESSAGES...

- Cool conditions with periodic showers and a few afternoon
  thunderstorms will continue through Wednesday.

- Severe weather is not expected but a few storms may produce
  small hail and gusty winds during the late afternoon and
  evening today. The best chances for strong storms will be west
  of Highway 31.

- Dry weather is expected Thursday and Friday but more rain
  returns early Saturday and into next week.

&&

.DISCUSSION...
Issued at 303 AM EDT Tue May 28 2024

Large negative height anomaly remains over the Great Lakes and
eastern Canada through the next two days. Multiple vorticity maxima
will rotate through the area during this time, leading to a
continuation of relatively cool and cloudy conditions with periodic
showers. One such vort max (currently a fairly potent one as seen on
latest water vapor imagery) will swing through our area during the
early morning and shear out a bit. This will support expanding
clouds and showers (a process already occurring at press time)
though unfavorable (stable) diurnal timing and overall modest
forcing will keep showers scattered. There is then likely to be a
lull in shower coverage around midday with a brief period of
shortwave ridging in between troughs. This will be our best chance
for more widespread sun but suspect at least some clouds to linger.
This break will be very brief as another vort max approaches during
the late afternoon/evening with increasing shower coverage once
again. This will probably be our most widespread round with
favorable diurnal timing and good midlevel CVA. A few thunderstorms
are possible but instability appears meager. Shear is also very
limited in our area and any storms that do develop have a very low
chance of becoming severe. However, steep midlevel lapse rates and
cold temps aloft yield some low potential for small hail and perhaps
some isolated gusty winds. The best chances will be in our far west
as reflected in the latest SWODY1. Highs today will be similar to
yesterday though a bit warmer in our NE half. Anticipate highs to
top out around 70F to low 70s.

Moist, cyclonic flow continues overnight into Wed and will maintain
chances for SCT showers with perhaps an isolated afternoon storm.
Winds back to a more northerly direction on Wed and this will keep
highs in the mid/upper 60s. Dry air advection and subsidence build
across the area Wed night but models now show yet another trough
swinging through the lower Great Lakes on Thu. Will hold Thu dry for
now given strong negative theta-e advection and eastward
displacement of best forcing but a widely isolated afternoon shower
is not impossible. More sun is anticipated and this will add a few
degrees to the highs despite continued northerly flow.

Sharp midlevel ridge finally moves into our region Thu night/Fri.
However highly amplified and progressive mid/upper level pattern
will yield another trough passage Fri night/Sat. Midlevel CVA and
low level moisture advection will support numerous showers but
forcing weakens with time and instability appears limited especially
given very poor diurnal timing. A brief break late Sat into Sun but
more rain chances arrive late Sun into Mon as active pattern
continues. Highs slowly climb back to near/slightly above seasonal
averages through the period.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 125 PM EDT Tue May 28 2024

Upper level disturbance dropping through Wisconsin this
afternoon with an area of showers and a few storms. Clearing
skies have allowed steepening low level lapse rates and an
increase in cu both here and upstream ahead of the wave. Models
vary on start of chances for showers/storms, but seem to focus
the greatest coverage (and chances for thunder) maybe as early
as 23Z at KSBN but more likely in the 1-4Z period. KFWA more
questionable with loss of heating and narrow window for thunder
potential. Have made some adjustments with tempo MVFR groups for
cig/vsby as well as thunder in most favored period. Can`t rule
out some locally gusty winds or small hail, mainly at KSBN, but
not covered in TAFs. Showers and MVFR cigs should persist
overnight with the potential for a drop to IFR mainly at KSBN or
during showers. While the showers should move away during Wed
morning, flight conditions may be slow to improve so MVFR
conditions maintained through the end of the period.

&&

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

&&

$$

DISCUSSION...AGD
AVIATION...Fisher