Area Forecast Discussion
Issued by NWS Northern Indiana

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

000
FXUS63 KIWX 131630
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
1230 PM EDT Wed Mar 13 2024

.KEY MESSAGES...

- Multiple rounds of thunderstorms are expected late tonight into
late Thursday.

- A few strong to severe storms are possible Thursday afternoon and
evening. Confidence is low at this time.

- Turning cold again early next week.

&&

.DISCUSSION...
Issued at 245 AM EDT Wed Mar 13 2024

One more quiet and overall pleasant weather day anticipated today. A
shortwave will pass to our south early this morning while general
longwave ridge building will take place today with the ridge axis
passing during the early evening. Can`t completely rule out a stray
shower today. First, in our SW with passing shortwave and some
marginal theta-e advection. Second, during the late afternoon in our
NW half given increasing warm/moist air advection. Chances for both
appear very low however given very dry antecedent airmass and late
arrival of true warm front/theta-e surge. Will hold with silent 10
PoP`s for now. Highs will be at least as warm (if not a degree or
two warmer) today given steady WAA and a milder start this morning.
There will still be a fair amount of clouds (similar to yesterday).
Less fire weather concern today though as surface gradient becomes
much weaker and dewpoints slowly climb (at least into the mid 40s).

Late tonight into Thu is the primary concern for this forecast
package with the potential for some strong/severe storms. A piece of
the western CONUS trough is expected to break off and eject NE into
strongly confluent flow over our region. This will send a weak
surface low through the area supported by strong prefrontal
warm/moist air advection and associated building convective
instability. Wind/shear profiles are highly supportive of organized
convection (850mb winds near 40 kts and 500mb winds near 70 kts) but
as is so often the case the instability picture is muddy. Multiple
rounds of convection are likely and this leads to low confidence in
the final mesoscale picture. The primary source of uncertainty
centers around how far north the warm front and associated surface
low setup. Lower-res deterministic NCEP models indicate the warm
front blasts well north of here Thu morning with heavy rain over
central MI and largely dry conditions locally. Hi-res CAM`s suggest
the warm front stalls roughly in our northern CWA with potentially
several rounds of convection training through our area late tonight
and into the day Thu. This idea has some support in the ECMWF
and some lower res ensemble guidance as well given a weaker/more
sheared midlevel wave in highly confluent flow aloft. This is
currently the preferred solution given that upper air pattern
and the fact that it is often difficult to get warm fronts
through Michigan this time of year due to very cold lakes. This
scenario likely supports three distinct rounds of convection as
seen in several 00Z hi-res models. The first with the primary
theta-e surge during the early morning, followed by some type of
convective cluster around midday (noted in several models), and
finally with the cold front during the evening. This doesn`t
allow instability to ever really build (save for perhaps ahead
of the cold front Thu evening which is at the end of most
current hi-res guidance) suggesting primarily an isolated heavy
rain threat with perhaps some pockets of gusty winds/hail. This
will have to be watched closely though because midlevel lapse
rates are impressive (over 7 C/km) and while low level moisture
isn`t extreme it could still be enough to generate 500-1000 J/kg
of MUCAPE (sufficient in this kinematic environment). If this
better instability does materialize, all hazards are possible.

Main story for the rest of this forecast is a major dose of calendar
reality. Deep upper low settles into the Great Lakes early next week
with much colder temps, breezy conditions, and periods of light snow
likely. Details are yet to be resolved but anticipate highs in
the 30s by Mon with lows well into the 20s. The best chances for
snow currently appear to be on Monday. Winter isn`t over but
this dose does look brief with warmer conditions returning by
the middle of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1230 PM EDT Wed Mar 13 2024

VFR/dry conditions will prevail through this evening with dry
airmass in place. Strong theta-e advection into a developing
warm front then brings showers and embedded thunder into the
terminals later tonight into Thursday morning. Primarily VFR to
start with this activity elevated in nature, through some
cig/vis restrictions possible within heavier convection toward
the end of the period.

&&

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

&&

$$

DISCUSSION...AGD
AVIATION...Steinwedel


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.