Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 251109 CCA
AFDIWX

Area Forecast Discussion...Correction
National Weather Service Northern Indiana
709 AM EDT Mon Mar 25 2024

.KEY MESSAGES...

- The combination of dry conditions and gusty winds could lead to an
elevated fire danger this afternoon.

- Widespread rain up to a half inch moves across the area tonight
with a second round of showers anticipated on Tuesday.

- Isolated thunderstorms and strong winds of 40-50 mph are possible
Tuesday afternoon with this second round of rain.

- Dry and tranquil weather is expected Wednesday through Friday.

&&

.DISCUSSION...
Issued at 306 AM EDT Mon Mar 25 2024

Deep, large mid/upper trough and associated surface low over the
Central Plains will slowly lift NE today. Strong southerly flow
downstream will advect a very warm airmass into our region today.
Anticipate highs well into the 60s based on latest guidance and
actually leaned toward warmer BC guidance given recent tendency for
greater mixing/lower dewpoints. No precip is expected during the day
as surface low and primary axis of forcing and moisture convergence
remain just to our west. It will be breezy with frequent gusts
around 30-35 mph, particularly in our western half where the
gradient is strongest. This does yield some fire wx concerns for
today but will likely fall short of red flag warning criteria
with RH`s around 30 percent and 10-hour fuel moisture still
above 10 percent.

Initial round of precip still expected to move across the area
overnight as upper low finally pushes far enough east to align nose
of impressive LLJ (850mb winds potentially well above 50 kts) in our
area. Good UVM noted ahead of the approaching trough with PW values
over an inch and at least neutral stability aloft. Anticipate a
quick quarter to half inch. Precip will only last about 6 hours in
any one spot though with quickly veering winds and approaching
midlevel dry slot. The overnight wind forecast is a tricky one.
Impressive winds noted just above the surface but with a very stable
profile and general isentropic ascent. Wind gusts should remain
capped around 30-35 mph for most of the night but some
potential for a few higher gusts near 12Z Tue as forecast
soundings show slightly deeper mixing behind the first round of
rain.

Much better chances for strong winds will be later in the day on Tue
as cold front crosses the area. There is still a fair amount of
uncertainty in how exactly this part of the forecast plays out
though. Models still show a lot of spread in timing the front with
considerable uncertainty in low level temp/moisture profiles that
will significantly impact available instability. Some 00Z models
still show a pocket of 500-1000 J/kg of SBCAPE but confidence is
low. If a line of modest convection does develop it will be capable
of mixing down some stronger wind gusts. There is also potential for
some 40 kt gusts in the region of isentropic descent behind the
front, though wind direction is not favorably aligned with the
isentropic surfaces. Bottomline there is certainly some potential
for 40-50 kt gusts on Tue but confidence is too low to issue an
advisory at this point (especially since the strongest winds may be
more convective in nature-to be handled with SPS`s/SVR`s).

Precip exits by late Tue evening and winds quickly relax. The rest
of the forecast remains tranquil as upper low pinwheels over Ontario
and supports cool but dry WNW flow over the Great Lakes. Precip
chances return by this weekend but this is associated with weak
shortwaves overtopping a very broad ridge across most of the CONUS.
Predictability of these small-scale features in fast flow aloft is
low and did not deviate far from NBM initialization. Temps will
steadily climb through the end of the week though.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 647 AM EDT Mon Mar 25 2024

The pressure gradient was still quite tight over northern
Indiana. Winds have temporarily diminished from SBN peak winds
last night of 32 knots a number of times. With the pressure
gradient persisting over the area, winds will pick up today and
become quite strong later today and especially tonight as a
surface low and front approach. Showers and strong winds are
likely near 06Z tonight with the passage of the front.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory until 4 AM EDT Tuesday for LMZ043-046.
     Gale Watch from late tonight through Tuesday evening for
     LMZ043-046.

&&

$$

DISCUSSION...AGD
AVIATION...Skipper


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