A Wintry mix possible Friday night

High thin clouds this evening clear as the sky remains clear overnight into Friday morning. The wind increases late tonight into Friday morning from the east and remains windy through the day with gusts to 30 mph. The east wind will hold off the rain for a bit.

Clouds increase during the day with rain chances increasing during the afternoon southwest of I-380. Areas northeast of I-380 remain dry during the day. Rain turns to a wintry mix overnight across all of eastern Iowa and then light snow. The snow ends as the sun comes up Saturday morning. Any snow accumulation across eastern Iowa will be 1” or less.The blue arrows show the direction the wild is coming from. Northeast wind tonight and east wind Friday.

The clouds clear Saturday as the wind lightens up from the northeast. High warm into the mid 40s. Sunday is beautiful with sunshine, a light wind and highs near 50.

There is a slight chance for light rain Monday with a gusty northeast windy. The first day of spring (Tuesday) is mostly cloudy and cooler with highs in the upper 30s.

Wednesday and Thursday is dry with high warming back into the upper 40s by Thursday.

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Posted under Forecast Discussion

This post was written by Schnack on March 15, 2018

Possible Wintry Mix Friday Night

A quiet night is on the way with a clear sky, light winds and lows in the 20s. Thursday is sunny with slightly cooler temperatures. Clouds increase Friday with a chance of rain and possible freezing rain during the evening and overnight. Toward Saturday morning light snow may be mixed in at times. Light rain/snow is possible Saturday morning before warming up to change to light rain before it ends by mid morning. Roads may be slick Friday night and early Saturday morning. Stay updated on the forecast for any changes. Here is a look at FutureTrack for Friday evening. The wintry mix is forecast to move east overnight.

Sunday is dry with highs in the upper 40s.

We are tracking another storm forecast to bring rain/snow to the area Monday with a gusty northeast wind. The rain/snow mix will change to snow Monday night into Tuesday. Some accumulation is possible. Wednesday is dry with highs back in the 40s.

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Posted under Forecast Discussion

This post was written by Schnack on March 14, 2018

TRACKING: Rain, Snow and Wind Monday

WINTER WEATHER ADVISORY  is in effect Monday into Tuesday morning for northeast Iowa.

 

Monday will be interesting.  All of eastern Iowa will have rain during the morning hours, so plan on a wet commute.  There may be a period of sleet and freezing rain mixing with the snow across northeast Iowa during the morning hours.

It will be windy with SE winds 15-30 mph, gusting 40+ mph at times.  Highest will be in the upper 30s north, to upper 40s south.

As we head into the afternoon hours, rain will begin to mix with, then transition into snow north of Highway 20.

Some of the snow could be heavy at times.  Snowfall amounts will be 3-6″, with locally higher amounts.

Near the Highway 20 corridor, 1-3″ of snow is possible Monday afternoon and evening.

Rain may mix with snow as far south as Cedar Rapids and Iowa City.  Any accumulation would be a trace to less than an inch.

We will have a dry period Monday evening, before the low pressure system tracks through eastern Iowa, and the backside brings wrap around snow showers after midnight, and into Tuesday.  An additional inch of snow is possible with that round.

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Posted under Forecast Discussion, Winter Weather

This post was written by Kyle Kiel on March 4, 2018

Rain vs. Freezing Rain vs. Sleet vs. Snow

A lot of the time when we have freezing rain or sleet in the forecast, with temperatures below freezing, we get asked “why isn’t this snow?”.  The answer has to do with the “vertical temperature profile.”  Twice a day, more than 900 weather balloons are launched worldwide, that have devices that record several weather parameters as it floats up in the atmosphere.  We look at the temperature and dew point when forecasting clouds, and precipitation.

This is a forecast sounding from one of our weather models for this morning’s freezing rain event.  Some of eastern Iowa saw rain and thunderstorms, others saw freezing rain, thunder freezing rain, and even a few reports of sleet.  I took this screenshot of a forecast sounding average for some of our northern counties, which saw the freezing rain this morning.  The temperature is across the bottom (in Celcius.. so 0°C=32°F), and is skewed as it goes up in pressure (left side).

For freezing rain, the atmospheric profile above is a pretty classic case.  We have temperature below zero from the top of the atmosphere, until we get down to about 10,000 ft. above the ground.  That’s when temperature go above freezing, and it’s a pretty deep layer of warmer air ,to about 2,000 ft off the ground.  The snow then melts into rain, but as it hits the cold layer at the surface, there’s no time for the rain to change back to snow, so it freezes on contact, and we get scenes like this.

To make things simple, all precipitation starts out as ice crystals way up in the clouds.  As the ice crystals grow/collide with others, snowflakes are formed, and continue to fall through the clouds.  What happens after that depends on the temperature (as well as wind & dew point, but we’ll focus on temperature).  If the temperature stays below 32° all the way through the atmosphere, we have snow.  If the snow hits a layer of shallow, warm air, the snowflake will begin to melt into a rain drop, but then falls into a deeper layer of colder air, and refreezes into an ice pellet, which we know as sleet.   See the picture below for a better idea.

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Posted under Forecast Discussion, Photo, Questions Asked, Winter Weather

This post was written by Kyle Kiel on February 20, 2018

A Few Chances of Snow

Scattered light snow moves across Iowa this evening. Accumulations around 1” are possible across most of eastern Iowa. Slightly higher amounts are possible south of Iowa City. Snow tapers off shortly after midnight. The wind is light and variable.

Wednesday is dry and cold with highs in the teens. Clouds continue at night with a few flurries possible. Lows remain above zero.

Light snow develops late Thursday afternoon or evening. Light snow continues through the night and most of Friday before tapering off during the afternoon. A few inches of snow are possible across all of eastern Iowa. The wind is from the northeast at 10-15 mph.

Another round of snow is possible Saturday. It starts around sunrise and tapers off around sunset. A few more inches of snow are possible here as well. The wind is from the northeast at 10-15 mph.

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Posted under Forecast Discussion, Winter Weather

This post was written by Schnack on February 6, 2018

Tracking Accumulating Snow Monday

We haven’t had a lot of snow this winter, but we will be adding to our snowfall totals as we head into Monday.

A storm system will develop and bring southerly flow into Iowa and other Midwestern states, which will add a little more moisture to the atmosphere and produce moderate to heavy snow at times.  Right now, the timing looks to be late morning into early afternoon.  However, that may fluctuate a little as this is still 36 to 48 hours out.

One idea we are pretty confident on at this juncture, is that the evening commute is going to be very tricky with visibility issues and snow on the roads.

Let’s take a look at the probability of snowfall across eastern Iowa.  All of us have a pretty decent chance of receiving 1″ of snow.

The chances for 2″ or more of snow goes down just a bit, especially across our northern counties.


And the good chances get narrower for 4″ or more of snow.

Here is the Storm Track 7 Snowfall Forecast as of 9 PM Saturday evening.  This forecast will be updated as more data gets into the weather center ahead of the storm on Monday.

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Posted under Forecast Discussion, Winter Weather

This post was written by Kyle Kiel on February 3, 2018

Snow Potential

Light snow and flurries will move out of eastern Iowa early this evening. The sky will turn partly cloudy and remain that way through the night. Lows tonight are not as cold with temperatures staying in the teens. Here is a look at the dusting of snow in Waterloo Friday evening.

Clouds quickly move back in by sunrise Saturday and linger through the day. A light snow shower or flurries are possible through Sunday morning. Any accumulation would be less than 1” and most locations less than 0.5”. The sky becomes mostly sunny Sunday afternoon. Saturday is warmer with highs in the 30s compared to Sunday with frigid temperatures in the teens and a gusty north wind.

We are tracking a better chance of light snow accumulations for Monday. Early indications show snow starting late in morning and tapering off in the evening. A couple of inches of snow are possible across eastern Iowa. The map below shows the area most likely to see 2″+ of snow Saturday evening through Monday evening.

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Posted under Forecast Discussion, Winter Weather

This post was written by Schnack on February 2, 2018

Sunday/Monday Storm Update as of Friday Evening

A mostly cloudy sky continues tonight through Saturday with temperatures above normal. Highs near 40 continues to melt snow.

Patchy drizzle or freezing drizzle is possible late Saturday night into Sunday morning. Temperatures are warm again reaching near 40 degrees in the afternoon with rain changes continuing through the day. Temperatures remain warm enough Sunday night as rain continues.

Temperatures warm into the upper 30s Monday with more rain in the morning. During the afternoon the wind increases from the northwest with temperatures start to drop into the low 30s changing light rain over to light snow. Light snow continues through the evening and tapers off shortly after midnight Monday night.

The map below shows where heavy snow (6″+) is most likely. Right now it is northwest of Charles City Sunday night into Monday. Any change in the track of the storm, that snow band will adjust as well. That means if it moves 50 to 100 miles southeast, so does that heavy snow. Stay updated on the forecast for any changes in the forecast.

Tuesday through Friday are dry with highs warming back to near 40 by the end of the week.

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Posted under Forecast Discussion, Update

This post was written by Schnack on January 19, 2018

Update on Sun/Mon Storm

The sky is mostly cloudy tonight and remains mostly cloudy through the weekend. Dry weather continues through Saturday with high temperatures in the upper 30s and low 40s. Friday is a breezy day with a south wind at 10-20 mph.

We continue to track a storm forecast to move across Iowa Sunday. The likely storm track brings us drizzle or freezing drizzle late Saturday night and early Sunday morning before temperatures warm above freezing. This happens as the sun rises Sunday morning. Rain chances continue through the day and most of the night.

High temperatures Monday are early in the morning and then fall into the 20s by the afternoon with a gusty northwest wind. Rain transitions to snow Monday morning and light snow is forecast to continue through the day before tapering off during the evening. Details on snow amounts and locations are not known yet since any wobble in the storm track will change the placement of the rain/snow and the amounts.

The yellow arrows on the maps show the likely path of the storm. The yellow lines show the possible shift either northwest or southeast of the track. The rain/snow on the map is based on the track with the yellow arrows. Any shift in that track will shift the rain/snow accordingly.

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Posted under Forecast Discussion, Update

This post was written by Schnack on January 18, 2018

Warmer and then possible storm

The sky is clear again tonight, but it is not as cold as last night. A breezy southwest wind continues through the night as low drop into the low teens.

Thursday and Friday are mostly sunny and warmer with highs near 40. Clouds increase Saturday as high temperatures warm to near 40 again.

We continue to track a storm forecast to move northeast across Iowa Sunday and Monday. The latest forecast track takes the low from southwest Iowa to northeast Iowa. The result is temperatures warm enough for rain Sunday and Sunday night in eastern Iowa. Late Sunday night into early Monday morning rain chances to snow. Light snow continues through Monday with light snow accumulations possible in eastern Iowa. Again keep in mind this forecast might adjust a few more times before Sunday gets here. Stay updated on the forecast.

The yellow arrows on the maps show the likely path of the storm. The yellow lines show the possible shift either northwest or southeast of the track. The rain/snow on the map is based on the track with the yellow arrows. Any shift in that track will shift the rain/snow accordingly.

Tuesday and Wednesday are dry with highs in the 20s.

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Posted under Forecast Discussion

This post was written by Schnack on January 17, 2018