IWX issues Area Forecast Discussion (AFD) at Feb 15, 12:28 PM EST059
FXUS63 KIWX 151728
AFDIWX
Area Forecast Discussion
National Weather Service Northern Indiana
1228 PM EST Sat Feb 15 2025
.KEY MESSAGES...
- Light freezing drizzle/rain and patchy fog still possible for
the next several hours. There will be a lull in precipitation
this afternoon and evening, but fog may still persist.
- Uncertainty remains in the forecast but heavy snow is possible late
tonight into Sunday. Lake effect snow showers ensue Sunday
afternoon and evening. 3-5" of snow is possible along and
north of US 30 from late tonight through Monday morning
(accounting for both the system snow and the lake effect snow
showers) and 1-2" south of US 30.
- Strong northwest winds with gusts up to 35-40 mph on Sunday
will result in blowing and drifting snow and sharply reduced visibilities.
Ground blizzard conditions are possible and travel will be
difficult on Sunday, especially on N-S oriented roads.
- Much colder air arrives Sunday night into Monday, with lows in
the single digits and highs only in the mid teens on Monday.
With wind gusts to 20 mph, Monday's wind chills will be as
cold as 5 to 15 degrees below zero!
- Colder than normal temperatures are expected to persist through
the work week.
&&
.UPDATE...
Issued at 846 AM EST Sat Feb 15 2025
Reports trickling in of anywhere from a half inch of snow
(south)to 2 to locally 3 inches further north. Southern tier or
so of counties now above freezing and will remain there through
the day.Lima did have a period of decent freezing rain per
recent obs, but they appear to be climbing above freezing.
Questions remain how fast/far north the warm air will make it as
well as duration of drizzle/freezing drizzle and need for the
current headline. Most likely will be dropping some counties
after the top of the hour where temps are above freezing. While
overall impacts are probably low the remainder of the morning,
may let the advisory remain across the north. Use caution on
unplowed and untreated surfaces.
The additional challenge comes with a likely need for another
headline tonight. Currently think there will be enough of a
break to allow one to drop and either issue the new one right
after expiration of the current advisory or wait till this
afternoon with the normal package.
&&
.DISCUSSION...
Issued at 635 AM EST Sat Feb 15 2025
You can expect everything but the kitchen sink in the next 24-48
hours as a weather system will bring a complex mix of precipitation
types to the area this weekend. In the past few hours, an area of
moderate snow moved through, which has caused roads to become snow
covered and slick. Any remaining snow showers will transition to a
freezing rain/rain mix this morning, with a potential for a glaze to
0.05" of ice possible. Meanwhile, a trough over the Rockies has
carved out a low pressure system that is ejecting out of Colorado
into Kansas this morning. This is the system we are watching to
bring potentially heavy snow to our forecast area late Saturday
night into Sunday morning.
As temperatures gradually warm into the mid to upper 30s for highs
this afternoon, precipitation transitions to a cold rain during the
daytime hours across the entire area. With increasing WAA thanks
to southwesterly winds, dry air should work into the area, which
could lead to periods of very light rain/drizzle or a few hours
of no precipitation at all at times this afternoon/evening. The
combination of rain and temperatures above freezing will help
to improve road conditions and compact any snow that is on the
ground. Patchy fog is also possible Saturday afternoon as rain
falls on the cold, snow-covered ground, although confidence is
low in this occurring.
As temperatures fall below freezing this evening, a changeover from
rain to snow will happen from northwest to southeast across the
forecast area late tonight. The aforementioned surface low will be
centered over Oklahoma by this evening and will lift northeast into
the Mid Mississippi River Valley. While this is not a slam dunk
forecast for snow, synoptically, this is a favorable setup for
accumulating snow and travel impacts. As the surface low deepens and
tracks northeast from roughly Paducah, KY to Cleveland, OH Saturday
night into Sunday morning, a deformation zone is likely to set up
somewhere across northern Indiana and northwest Ohio with heavy snow
likely. The left exit region of a strong jet streak will also be
over our area Saturday night, which will lead to low level
convergence and increasing lift, which will also help to aid in the
development of heavy snow. It is worth noting that hi-res guidance
does diverge in terms of coverage and exact placement of the
deformation zone. This is why headlines have not been issued for
Saturday night into Sunday, as there is still considerable
uncertainty in where exactly the highest snow totals will be.
After the main deformation zone pivots through the area, scattered
snow showers will persist across the area as a favorable pattern for
lake effect snow will commence Sunday afternoon/evening. Favorable
parameters include northerly winds and low level convergence, delta-
Ts of -15C, and negative theta-e lapse rates. Additionally, as the
surface low exits to the northeast Sunday morning and continues to
deepen, a tight pressure gradient will develop across our area and
result in very strong winds throughout Sunday. Roads will already be
snow covered and travel will be very hazardous Sunday morning and
afternoon, with the winds and lake effect snow showers making travel
impacts even worse. Northwesterly wind gusts up to 40 mph on Sunday
could lead to ground blizzard conditions, especially in rural areas
and on N-S oriented roads. Expect sharply reduced fusspots
(either due to falling and/or blowing snow) and very hazardous
travel on Sunday. This may change as the next shift gets a
better idea of the forecast, but right now, thinking that a
swath of 3-5" snow totals will be possible along and north of US
30 from this evening through Monday morning (accounting for
both the system snow and the lake effect snow showers) and 1-2"
south of US 30.
Much colder air arrives on Monday as a large area of high pressure
overspreads and expands across the Central CONUS. Get ready for a
brutal start to the new work week as lows on Monday morning will be
in the single digits and highs will only be between 10 to 15
degrees. Given that the forecast for snow has trended upwards for
Sunday, this had also led to the forecast for Monday to be colder
than previous forecasts. Wind gusts up to 20 mph will result in
winds chills as cold as -5 to -15 degrees throughout Monday.
Temperatures will remain seasonably cold with highs only in the
teens through Friday. Occasional periods of snow showers will
be possible throughout the week.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1218 PM EST Sat Feb 15 2025
Chances for fog and some drizzle continue at both terminals but
temps have risen above freezing. Expect a rain/snow mix to
return to SBN after 21Z, becoming all snow around 23Z. At FWA,
more of a winter mix, including sleet is possible after 00Z this
evening, before becoming all snow early Sunday morning. Mainly
IFR or worse conditions can therefore be expected through much
of the period at both sites. Winds will also pickup on Sunday
with gusts up to 30 kts, which could cause some blowing snow,
further reducing visibilities.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Winter Weather Advisory until 1 PM EST /noon CST/ this
afternoon for INZ005>009-012>015-017-103-104-116-203-204-
216.
OH...Winter Weather Advisory until 1 PM EST this afternoon for
OHZ001-002-004-005.
MI...Winter Weather Advisory until 1 PM EST this afternoon for
MIZ078>081-177-277.
MARINE...Small Craft Advisory from 1 AM to 7 AM EST Sunday for LMZ043-
046.
Gale Warning from 7 AM Sunday to 1 AM EST Monday for LMZ043-
046.
&&
$$
UPDATE...Fisher
DISCUSSION...Johnson
AVIATION...Cobb
Source:
IWX issues Area Forecast Discussion (AFD) at Feb 15, 12:28 PM EST---------------
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