Lafayette, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

904
FXUS63 KIND 061318
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
918 AM EDT Sun Oct 6 2024

.KEY MESSAGES...

- Elevated fire weather risk this afternoon, especially along and
  north of the I-70 corridor

- Dry and warm weather continues today.

- Seasonable temperatures to start next week, warming trend back to
  upper 70s mid to late next week

&&

.FORECAST UPDATE...
Issued at 918 AM EDT Sun Oct 6 2024

Surface analysis this morning shows a cold front stretching from
Michigan to eastern IL and then southwest to southern MO. Strong
high pressure was found over the northern plains. This cold front
was moisture starved. GOES16 shows clear skies across Indiana and
only shows a few high clouds over Michigan ahead of the front.
However, due to strong low pressure over Ontario, a moderate
pressure gradient remained in place across Central Indiana.

This afternoon the front is expected to sweep across Central
Indiana, eventually allowing the winds to become northwesterly.
However in the meantime Indiana will see plentiful sunshine and good
mixing with southwest flow in the warm sector. Given this, expect
temperatures to overperform somewhat, reaching the middle 80s. Due
to the moderate pressure gradient, gusty winds will be expected this
afternoon. Gusts around 25 mph will be possible. Skies will remain
sunny as forecast soundings remain dry with convective temperatures
that are unreachable.

&&

.SHORT TERM (Today and tonight)...
Issued at 255 AM EDT Sun Oct 6 2024

Today...

An upper system will move through the Great Lakes today. At the
surface, a cold front will move through central Indiana this morning
into early afternoon. The cold front will be moisture starved, with
moisture confined to the Great Lakes area and the upper system.

Thus, only expect some patchy mid and high clouds as the front moves
through today. Winds will increase as the pressure gradient tightens
with the frontal passage, and mixing will bring down some gusts from
stronger winds aloft.

Winds will gust into the 20 to 25 mph range, with perhaps a few
higher gusts. The higher wind gusts look to be across the northern
forecast area where stronger winds aloft will exist.

Temperatures will warm quickly today with sunshine. Better cold
advection won`t arrive until later in the day. Given the above and a
warmer start than previous days, expect highs in the lower to middle
80s across much of the area. Some upper 70s are possible in the
north where cold advection will be strongest.

Drier air will work in quickly behind the front, and the combination
of the drier air and warm temperatures will lead to low relative
humidity. See the Fire Weather section for additional information.

Tonight...

Winds will diminish quickly with loss of heating/mixing. High
pressure will build into the area, but center of the high will
remain west of central Indiana.

Skies will be clear for much of the night, but some scattered lower
clouds may move into the far north late tonight in the cold
advection regime. The combination of dry air, lighter winds, mostly
clear skies, and cold advection will lead to low temperatures in the
lower to middle 40s.

Areas sheltered from any wind will have the potential to see the
coldest readings.

&&

.LONG TERM (Monday through Saturday)...
Issued at 255 AM EDT Sun Oct 6 2024

A prolonged warm and dry spell will persist through next week as
strong high pressure and ridging dominates the region. Despite sunny
skies and warm temperatures, there will be enhanced fire danger
concerns each afternoon, as well as potentially deteriorating
drought conditions once again.

High pressure dives southeast out of Canada this weekend becoming
centered over the state by Tuesday. Cold air advection and northerly
flow ahead of the system will "cool" temperatures down from summer-
time levels to near normal for this time of year. Normal highs and
lows are currently right around 70 and 50, though steadily declining
through the month - by mid month we lose another 4-6 degrees on
average. Monday and Tuesday will likely be the only days in the long
term that are "near normal" as a warming trend begins as ridging
strengthens and high pressure shifts eastward late in the week. Both
long term and deterministic guidance are in good agreement with this
warming trend with highs reaching the upper 70s again by Friday and
into next week.

Dry conditions will likely lead to enhanced diurnal temperature
ranges, with lows each night dropping to the 40s to low 50s.
Watching Monday night into Tuesday morning for the coolest lows in
the long term period as optimal conditions for radiational cooling
set up with high pressure directly overhead. Watching the Wabash
River Valley and wind sheltered areas away from urban areas for the
potential for mid to upper 30s.

Will continue the trend of adjust forecast dewpoints and RH downward
toward the NBM10-25th percentile during the afternoons many days
this week, as despite relatively light winds, it will require only
modest mixing in a very dry column to produce potentially
substantial dewpoint drops in the afternoons. This is an area where
NBM is known to struggle, often significantly. The aforementioned
light winds will mitigate fire concern somewhat, at least with
respect to reaching red flag conditions, but continually drying
fuels and afternoon RH values potentially nearing critical levels
will present at least some concern.

Longer term guidance does suggest some potential for precipitation
near or just beyond the end of the forecast period with another
quick moving upper low and cold frontal passage late next weekend
into early the following week, but long term outlooks remain fairly
strongly warm and dry, and prevailing westerlies look to remain
displaced well poleward for most of the next couple of weeks at
least. CPC 6-10 and 8-14 day outlooks are strongly indicative of
below normal precipitation and nearly as strongly indicative of
above normal temperatures, and this is well-supported by long term
guidance, including the CFS.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 630 AM EDT Sun Oct 6 2024

Impacts:

 - Wind gusts around 20kt today, with a wind shift to northwest

Discussion:

VFR conditions are expected throughout the period. A cold front will
move through the sites late morning into mid afternoon. Some mid
cloud may accompany the front, and a wind shift to the northwest
will occur with it.

Can`t rule out some brief low level wind shear at the start of the
period with some stronger winds aloft. Winds will gust to around
20kt during the day today both ahead and behind the front.


&&

.FIRE WEATHER...
Issued at 255 AM EDT Sun Oct 6 2024

An elevated risk of grass and field fires will occur this afternoon
across central Indiana, especially across areas along and north
of the I-70 corridor.

Over a week has passed since significant rainfall, and observations
indicate that 10 hour fuels continue to dip to near critical levels
for a few hours during the afternoon.

The drier air will be moving in coincident with the warmest
temperatures will lead to minimum humidity in the 20 to 30 percent
range over much of the area, with the lowest values in the northwest
where drier air will arrive first. Some of the hi-res models
indicate the potential for sub 20 percent humidity, and the DESI
viewer is showing around a 40 percent chance of this happening in
the Lafayette to Kokomo areas.

The above, combined with wind gusts over 20 mph (and potentially 25
mph north) and the lower afternoon fuels, will lead to the elevated
risk for grass and field fires. Will issue a Special Weather
Statement to highlight the threat.

&&

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

$$

UPDATE...Puma
SHORT TERM...50
LONG TERM...CM
AVIATION...50
FIRE WEATHER...50