Zone 5/6 Active pattern at hand. Winter storm potential early next week.

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Video forecast: M. 

Forecast Discussion:

EVENING – TONIGHT: Clear conditions started the day on Wednesday, but clouds have built-in across the forecast region and snow has moved into western Illinois. This is associated with an upper level vorticity maximum that is moving across the forecast area.

now

As this disturbance moves in so will the snowfall associated with it. By 5-6 PM snow looks to be falling across zone 6 in Illinois. While I think a lot of this will be more on the light to moderate side, some heavier bursts can’t be ruled out.

5pm

Through the evening the upper level disturbance will move in and out of the region. It looks like a lot of the energy will exit the forecast area after 10 PM or so. I think snow this evening will begin to taper off after 9-10 PM for a couple of reasons. The first being its source of lift will be moving out of the region and the second the air will be very dry. So without an upper level disturbance available to lift it and little moisture to sustain it, these will not be able to self-sustain.

10pm

With that being said some light snow showers will still be ongoing across zone 6 and western zone 5 around 1-2 AM tonight.

thu1am

Overnight snow showers will start to come to an end with only some isolated areas of snow and some flurries remaining.   

Lows overnight will be in the middle teens to mid-20. However, with winds still gusting from 15-25 mph, wind chills will be in the single digits to middle teens.

The latest HRRR model does show accumulations of .5-1” across zone 6. If some better banding were to occur there may be a couple of places that get between 1-2”, but those would likely be very localized.

snow

THURSDAY: A few snow showers/flurries may remain across zone western zone 5 and zone 6 through 7-8 AM Thursday. However, with a large area of high pressure quickly building into the region very dry air will start to work into the middle and lower levels by late morning ending snow chances.

thuhigh

Through the day dry air will continue to invade all layers of the environment. As it does clouds will be on the decrease and I would expect sunshine by at least early to mid-afternoon on Thursday.

Highs on Thursday will be low 30’s to around 40° south. If sunshine can be realized soon, highs in the low 40’s are possible, especially with the dry air in place.

Overnight Thursday clouds will start to thicken up to the west and another clipper system will start to move into the forecast area. Snow will start to enter Illinois into the early overnight, but right now I would anticipate this to be north of the forecast zones.

Lows overnight Thursday will be in the middle teens to mid-20.

FRIDAY: Snow will continue to work to the southeast through the day one Friday, this associated with a pretty intense upper level area of vorticity.

FRI 500 MB
FRI 500 MB

Current thinking is that the snow associated to with this system will be mainly north of zones 5/6. However, northern portions of the zones and eastern zone 5 could see some snowfall from this storm.

While obviously exact timing will have to be ironed out over the next 24 hours or so, the RPM shows snow becoming possible across northern and eastern zone 5 through by 7-9 AM Friday morning.

FRI 7 AM
FRI 7 AM

Through the morning hours snow will continue moving across northern and eastern zone 5 and coming down at a pretty good clip at times.

FRI 12 PM
FRI 12 PM

Through the evening snow looks to come to an end around 5-7 PM. However, chances of snow showers look to linger across those zones through midnight.

FRI 7 PM
FRI 7 PM

Looking at snowfall totals through late Friday night it looks like 1-3” will be possible north of zone 6. Western portions of zone 5 could see some accumulating snow in the northern portions of the zone. However, better chances of accumulation look to be in eastern portions of zone 5.

snowfallfri

Overnight Friday an area of high pressure will start to build in from the areas northwest. Dry air will quickly move in with it. While I do think some snow showers will remain possible overnight Friday into very early Saturday across eastern zone 5, dry air will quickly cause any leftover moisture to evaporate.

Lows Friday night will be in the teens to around 20.

WEEKEND: An area of high pressure will build into the forecast area on Saturday. This will allow for quiet conditions for the daytime hours. Overall it looks to be mostly sunny to partly cloudy through the day Saturday.

sat high

Winds do look to be a little gusty through the day with gusts up to 20-30 mph possible.

Highs will be in the middle teens to upper 20’s. However, wind chills may make it feel more like lower to middle teens at times

Sunday through mid to late afternoon looks pretty quiet across the region. However, we will be a couple of areas of low pressure to the regions west and northwest.

By late Sunday these two areas of low pressure look to phase to the southwest of the forecast zones. Depending on where and when this occurs a winter storm setup could be on tap for the region by late in the day on Sunday.

MONDAY – TUESDAY: Forecast guidance has remained persistent in phasing the two lows and tracking the single low through the Ohio/ Tennessee Valley early next week. While exact timing and location is something that will have to be fine-tuned over the next several days, the possibility for a winter storm event exists late Sunday through early Tuesday across the forecast area.

gfsmon

The latest probabilistic outlook from the Weather Prediction Center Shows a 50-70% chance of a significant snowfall event early next week. Significant being 5″+.

sig snow potential

7 DAY FORECAST

THURSDAY: AM SNOW SHOWER, THEN DECREASING CLOUDS. HIGHS IN THE MID 20’S TO AROUND 40 SOUTH. NORTHWEST WINDS AT 6-12 MPH.

THURSDAY NIGHT: MOSTLY CLOUDY, SNOW CHANCES WEST AND SOUTH. LOWS IN THE MID TEENS NORTH TO MID 20’S SOUTH. SOME ACCUMULATIONS POSSIBLE.

FRIDAY: MOSTLY CLOUDY WITH SNOW NORTH & EAST. HIGHS IN THE MID 20’S NORTH TO LOW 40’S SOUTH. NORTHWEST WINDS 5-15 MPH, GUSTING TO 25 MPH. ACCUMULATION LIKELY.

FRIDAY NIGHT: PARTLY TO MOSTLY CLOUDY, SNOW ENDING. LOWS IN THE SINGLE DIGITS NORTH TO AROUND 20 SOUTH.

SATURDAY: PARTLY CLOUDY TO MOSTLY SUNNY, PERHAPS SOME SNOW SHOWERS IN ILLINOIS LATE? HIGHS IN THE MID TEENS NORTH TO UPPER 20’S SOUTH. NORTHWEST WINDS AT 5-10 MPH, GUSTING TO 20 MPH. SOUTH TO SOUTHEAST WINDS AT 5-15 MPH, GUSTING TO 25 MPH.

SATURDAY NIGHT: INCREASING CLOUDS, A FEW SNOW SHOWERS POSSIBLE. LOWS IN THE SINGLE DIGITS NORTH TO AROUND 20 SOUTH.

SUNDAY: MOSTLY CLOUDY, SNOW POSSIBLE LATE. HIGHS IN THE MID 20’S NORTH TO MID 30’S SOUTH. SOUTHEAST WINDS AT 5-15 MPH.

SUNDAY NIGHT: CLOUDY, SNOW POSSIBLE SOUTH. LOWS IN THE UPPER TEENS NORTH TO UPPER 20S SOUTH.

MONDAY: CLOUDY WITH SNOW POSSIBLE, SOME HEAVY? HIGHS IN THE UPPER 20’S TO MID 30’S. ACCUMULATION POSSIBLE.

MONDAY NIGHT: CLOUDY WITH SNOW POSSIBLE. LOWS IN THE UPPER TEENS TO UPPER 20’S. ACCUMULATION POSSIBLE.

TUESDAY: CLOUDY WITH HIGHS IN THE MID 30’S TO MID 40’S.

TUESDAY NIGHT: CLOUDY WITH A CHANCE OF RAIN AND/OR SNOW. LOWS IN THE MID 20’S TO AROUND 40.

WEDNESDAY: CLOUDY WITH A CHANCE OF RAIN AND/OR SNOW. HIGHS IN THE MID 30’S TO MID 40’S.

WEDNESDAY NIGHT: MOSTLY CLOUDY WITH LOWS IN THE MID 20’S TO LOW 30’S.