Westfield, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

977
FXUS63 KLOT 130817
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
317 AM CDT Fri Jun 13 2025

.KEY MESSAGES...

- Scattered showers and possibly a couple of thunderstorms Today
  into Saturday, especially south of I-80.

- Very warm and humid with occasional chances for showers and
  thunderstorms early to mid next week.

&&

.DISCUSSION...
Issued at 317 AM CDT Fri Jun 13 2025

Through Saturday:

Early morning GOES vapor imagery depicts a closed mid-level low
centered near Joplin MO, along with a weak surface low
reflection. A broad region of modest low-level southerly flow
was evident ahead of this feature across the lower and middle
Mississippi River Valley, pulling deeper moisture up from the
south as seen in 00Z RAOBs from Jackson MS and Little Rock AR.
This moisture will continue to spread north into our region
today, as the mid-level low lifts slowly east-northeast across
MO. Regional radar imagery already indicates showers spreading
northward into central IL at this hour, and these are expected
to move into the WFO LOT forecast area a little later this
morning. Not much in the way of lightning has been noted with
this area of precipitation, as lapse rates are generally moist
adiabatic throughout much of the column per the above referenced
soundings.

At the surface, a weak, nearly stationary frontal boundary was
evident from roughly along a Moline-Bloomington-Lafayette line
along the WFO ILX/LOT border area. This front is forecast to
lift north as a warm front today in response to the low-level
warm/moist advection ahead of the upper low, perhaps to around
the I-80 corridor this afternoon. Shower coverage is expected to
be highest across the southern half of the cwa, generally along
and south of the frontal boundary and closer to better mid-
level forcing associated with the mid-level wave. Despite the
relatively weak lapse rates, a few isolated thunderstorms can`t
be ruled out this afternoon and early evening, again mainly near
and south of the warm front if enough sun can make its way
through otherwise fairly extensive cloud cover.

The mid-level low is progged to gradually weaken into an open
wave later tonight into Saturday as it tracks across
central/southern IL and IN. This will tend to maintain the focus
for showers across the southern half of the forecast area into
Saturday, while eventually shifting to the southeast Saturday
afternoon as the mid-level wave shifts east. With slow cell
movements and deep moisture (forecast p-wats approaching 2"),
some localized rainfall amounts of an inch or more appear
possible especially southeast of I-55.

Easterly surface winds will continue to keep temperatures
cooler near Lake Michigan both today and Saturday, with highs in
the 60s likely along the immediate shore. Highs in the upper
70s to lower 80s are likely farther inland, with warmest
readings likely toward northwest IL where less impact from
thicker cloud cover and more widespread showers are expected.
Mid-80s are likely across our western cwa by Saturday afternoon,
as cloud cover decreases behind the departing disturbance.

Ratzer

Saturday Night through Thursday:

As the upper level wave moves east and better height rises move
over northern Illinois, Saturday night should be dry. Overnight
lows will drop into the low 60s, with a few upper 50s closer to
the Wisconsin border. Sunshine should filter through any clouds
on Sunday to help warm up the area into the low to mid 80s
during the day, though northeast winds will help keep the
shoreline cooler in the upper 60s and low to mid 70s.

Both EPS and GEFS models have pulled back on the precipitation
chances on Sunday. Both have a shortwave aloft that forms over
the Upper Mississippi Valley early Sunday, tracking it
southeastward. However, they keep the track of the wave south
and west of the forecast area. There will be lingering moisture
around the region and with diurnal heating mid-level lapse
rates will steepen in the afternoon, there could be enough
instability to have some showers and an isolated rumble of
thunder crop up (best chances east of Interstate 39). With such
weak forcing, PoPs were trimmed back to just a slight (less than
25 percent) chance mention, though it is imagined there will be
plenty of drier periods during the day.

No changes were made to temps and PoPs that the NBM provided
for Monday and Tuesday. High temperatures each day look to be in
the 80s, and slowly creep into the upper 80s as winds turn
southerly to allow for better warm air advection. Many of the
shower and thunder chances on these two days will probably be
diurnally driven, but with models showing a few weak waves
passing over. PoPs increase to around 30 to 40 percent chance
at this range.

There remains a decent signal in the ensemble guidance for a
stronger synoptic system and associated cold front to approach
the region on Wednesday. This may be a period to watch for
organized convection and a threat for strong to severe
thunderstorms in the region. However, deterministic guidance is
still flip-flopping on the details as the latest 00Z GFS pushes
the surface low farther north and into Wisconsin, while the 00Z
Euro now has it moving slower and passing right over northern
Illinois. But at this range it is hard to have confidence in the
exact outcome given the discrepancies. Nevertheless, if the
Wednesday-Wednesday night timing comes to fruition, then
Thursday would likely end up mainly dry and slightly cooler/less
humid in the wake of the cold front passage.

DK

&&

.AVIATION /06Z TAFS THROUGH 12Z SATURDAY/...
Issued at 1230 AM CDT Fri Jun 13 2025

Key Aviation Messages for the current TAF period:

- 30 percent chance for showers during the afternoon and early
  evening

- Potential for MVFR cigs after 00Z

This evening`s shower chances have petered out. High clouds
are still seen on satellite, but VFR conditions will prevail
through Friday. Winds remain out of the northeast and are
weakening, potentially becoming light enough to be variable at
select sites around the region.

No major changes to the shower chances in the forecast for
Friday. As an upper level wave moves over the area, it brings
the chance for showers. But weaker forcing lowers confidence in
exact coverage which could range from isolated to widely
scattered. Best chances look to be around KGYY and to the south
during the afternoon, but could linger into the evening and
spread northward depending on the movement of the wave. An
eventual VCSH or TEMPO for -SHRA mention may be needed with
later updates.

Through much of the day, winds are expected to be at or less
than 10 knots. Guidance is suggesting southeasterly winds in the
morning ahead of the wave, then slowly becoming more easterly
and eventually northeast Friday night.

Guidance is in slight disagreement with cig trends overnight
into Saturday morning. As that wave weakens in the evening,
there was enough confidence to introduce MVFR cigs into the TAF
(though lower confidence in timing of the cigs). Some of the
guidance is being very aggressive in the potential for IFR
cigs. But without a lot of agreement, it was only introduced as
a FEW group at this time.

DK

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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