Wintry mix possible this weekend


Northern Indiana, southern Lower Michigan and/or northwestern Ohio could receive a wintry mix of precipitation this weekend, according to a “Hazardous Weather Outlook” that the northern Indiana office of the National Weather Service issued this morning.

As usual with forecasts several days in advance, meteorologists still have a large amount of uncertainty regarding how strong the expected storm system will be and exactly where it will go.

If you have travel plans this weekend, it would be wise to continue watching official forecasts as the period nears. One of my favorite sources is

NWS: Rain will change to snow, high winds will blow

NWS map graphic showing winter weather advisory and wind advisory
NWS graphic

Forecasters expect rain today, changing to snow this afternoon and evening in northern Indiana, southwestern Lower Michigan and northwestern Ohio, according to various text products from the northern Indiana office of the National Weather Service (NWS) (Facebook, Twitter).

They expect the change to snow to begin this afternoon in the western counties of the office’s 37-county warning area (CWA) and progress to the eastern counties by this evening.

The office has issued a Winter Weather Advisory for counties along the western edge of its CWA (see graphic above), where meteorologists expect one to three inches of snow with locally higher amounts. The winter weather advisory is in effect from 4 p.m. to midnight.

They issued a Wind Advisory for most of the CWA’s Ohio counties from 4 p.m. this afternoon to 3 a.m. tonight. There, they forecast sustained winds of 20 to 30 mph, with gusts up to approximately 45 mph.

The NWS issued a Special Weather Statement for the rest of the CWA that alerts readers to potentially difficult driving conditions by this evening, due to slushy roads and reduced visibilities.

NWS surface analysis map, 7 a.m. EST
NWS surface analysis map, 7 a.m. EST

Believe it or not, there is still some uncertainty regarding when the change from rain to snow will happen and therefore, how much snow will fall. That’s because there’s still a chance that the low pressure system that will be responsible for all this weather could follow a different path than forecast. “Just a 20-30 mile shift west or east will make all the difference,” writes NWS meteorologist Mark Steinwedel in an Area Forecast Discussion the northern Indiana office issued this morning.

As of 7 a.m. EST today, that area of low barometric pressure was just south of Indiana (see map above; black arrow points out the low). When meteorologists see what path the low actually takes, they’ll be better able to forecast snowfall timing and amounts.

Christmas Storm snowfall forecast remains difficult

Graphic: Snow background with word, "uncertainty" stamped over it

“Uncertainty.” If you’ve been following this blog (or any other information sources) for information on a winter storm forecast for Christmas Eve, you’re probably growing weary of that word.

But “uncertainty” remains the key word, because the low pressure system that will be responsible for the storm is just beginning to form in the area of the Gulf of Mexico this morning.

Currently, that low pressure system is forecast to move straight up through Indiana. Most of the snowfall will be to the west of the low. That means if the low goes right over you, you won’t get as much snow as you will if it goes east of you.

Meteorologists use a suite of computer forecast models to predict things like where that low pressure system will go. Different models calculate things differently, so meteorologists don’t rely on a single model, they look at several. Agreement between the outputs of several models helps them forecast confidently.

Unfortunately, as of this morning, the range of storm tracks provided by those models “remains a bit wider than one would like to see at this time,” writes meteorologist Sam Lashely in an “Area Forecast Discussion” that the northern Indiana National Weather Service office issued.

Lashley continues, “The details with where any accumulating snowfall will develop remain in question,” and “we continue to stress the uncertainty and need for people traveling to continue monitoring forecasts and remain aware.”

NWS Northern Indiana takes stab at accumulation forecast

Preliinary snow forecast map

The northern Indiana office of the National Weather Service sent an email message to emergency managers in its forecast area this afternoon that included a map (above) showing a very preliminary snow accumulation forecast for the coming winter storm.

The NWS wrote:

  • Rain is expected to change to snow from west to east across the area Wednesday evening.
  • Snow accumulations of one to three inches along with slick roads are possible from this system.
  • Confidence in the snow accumulation forecast is low at this time, but since the snowfall could impact the busy Christmas Eve traveling period, the NWS wanted to make sure emergency managers are aware of the potential.

Expected snow accumulations from Christmas storm remain a “long shot”

Snowy road with words "Christmas Storm" superimposed

Numerous questions remained regarding a winter storm forecast for around Christmas Eve, according to an “Area Forecast Discussion” issued this morning by the Northern Indiana office of the National Weather Service (NWS).

Uncertainty remained high with respect to the timing and location of a changeover from rain to snow and resultant amounts of snow, writes NWS meteorologist Sam Lashley.

“Current indications still support a later changeover to snow Wednesday afternoon. With a very wet and relatively warm ground from rain it will be difficult for snow to accumulate initially,” Lashley writes. “Expected accumulations remain a long shot and still highly uncertain.”

“Those with travel plans or concerns should continue to monitor updated forecasts through the early part of the week leading up to the storm,” Lashley concluded.

One good source for updated forecasts is the NWS website, This blog will attempt to keep readers updated as well, but the NWS website or your favorite broadcast website will have more information and sooner.

Forecast intensity of Christmas storm now much weaker

Snowy road with words "Christmas Storm" superimposed

The forecast intensity of a winter storm Christmas Eve and Christmas Day is much weaker than earlier forecasting models suggested, according to an “Area Forecast Discussion” issued this morning by the Northern Indiana National Weather Service office.

Forecaster Sam Lashley writes of two low pressure systems, the first of which would bring rain to the northern Indiana, southern Lower Michigan and northwestern Ohio area Monday afternoon in to Tuesday. Some forecast models suggest that a second low pressure system will develop behind the first one, but others disagree.

If the secondary system develops, the area could get more snow on Christmas Eve and Christmas Day than if it does not, but meteorologists remain quite uncertain about what will happen.

For now, the bottom line is:

  • There is still a chance of snow on Christmas Eve.
  • Uncertainty continues regarding the track and strength of the storm.
  • As of this morning, it appears that any significant snow accumulation will miss the northern Indiana, southern Lower Michigan and northwestern Ohio areas.
  • Things could still change, so anyone who has holiday travel plans should keep checking back with and other reliable sources of weather information.

Excellent EmComm tips from St. Louis Metro ARES/RACES

ARES LogoThe St. Louis (Mo.) ARES/RACES organization published some excellent tips for ham radio operators who are involved in emergency communications and/or public service events. You can read the entire thing on their website and below are a few of my favorites, with some of my own comments.

Things to avoid saying on the air, Number 1

“Okay, I’ll do it. But it’s not actually my job. The guy who’s supposed to do that is always away from the table doing something else.” The other operator doesn’t want to hear any of that and it ties up the frequency. Make a note of your complaints in your log and bring them up at the debriefing, but keep them off the air.

From Gary Ross Hoffman, KB0H

This is so true. An addition problem caused by such transmissions is the damage to ham radio’s image caused when representatives of served agencies and/or members of the general public overhear such comments through the radios of nearby operators. Even though we are amateur radio operators, we must always behave professionally on the air, especially when involved in public service.

The value of tactical call signs

Tactical call signs such as “Shelter 5”, “Net Control”, and “EOC” are descriptive and give immediate information. They can be very useful during planned events and during emergencies. Do not, however, forget to include your FCC call sign at ten minutes intervals and at the end of each contact.

From Various experienced operators

Just a bit of clarification here: During a public service event or emergency communications operation, a contact, QSO or (as the FCC Part 97.119  puts it) “communication” that lasts more than 10 minutes should be exceedingly rare! This means that if your FCC call sign is the last thing you say at the end of your last transmission during each contact , you should almost never have to worry about the 10-minute rule.

Never alter a message

Do not alter a message, even to correct a typographical error. What you think is right may actually be wrong. Moreover, any change you make might subtly alter the meaning of the message. Send or write it exactly as you receive it.

From Introduction to Emergency Communication course book

During public safety events, EmComm exercises and even NTS traffic nets, I’ve been amazed at how often I’ve heard this advice ignored. Even when relaying tactical messages (“Shelter one needs more cots”) verbatim transmissions are essential.

As a continuation of that thought, it’s equally important for radio operators to refrain from attempting to interpret messages. In other words, If the other operator requests clarification, I should not tell him what I think the served agency representative meant. I should instead relay the request for clarification to the representative and then relay his or her response.


  • Keep it brief
    Air time is precious, especially when there are numerous operators on the same frequency. Refrain from overexplaining things, engaging in personal greetings and chats, and anything else that might prevent important traffic from getting through.

    From Gary Ross Hoffman, KB0H

  • Are you following procedures?
    Operating procedures are developed from many hours of examining what went wrong during disasters. Familiarize yourself with the procedures and practice them in exercises. Arriving at a disaster scene and trying to freestyle it will only cause problems.

    From Gary Ross Hoffman, KB0H

These two tips reminded me of an operating procedure that many operators on EmComm nets don’t seem to know (based on what I hear): During a directed net, the only thing you need to say when calling the net control station (NCS) is your own call sign, once.

“Net Control, this is Aid Station Bravo” uses about twice as much air time as “Aid Station Bravo.”

During a directed net, we are not usually permitted to call anyone without first calling the NCS. The NCS operator knows this. Therefore, if I transmit my call sign and nothing else, the NCS will assume I’m calling him!

Likewise, a sharp NCS operator will answer such a call by transmitting only the call sign of the station that just called, not his own call sign! It should sound like this:

Aid station: “Aid Station Bravo”

NCS: “Aid Station Bravo.”

Aid station: “I have traffic for Logistics.”

NCS: “Logistics.”

Logistics: “Logistics.”

NCS: “Call Aid Station Bravo for traffic.”

Logistics: “Aid Station Bravo, Logistics.”  (here, both call signs are appropriate, but notice the absence of the unnecessary “this is” before “Logistics.”)

I hope you find these thoughts helpful. I welcome you to add your comments, using the link above (below the post title) and to share a link to this post using the convenient buttons below.


Christmas storm confidence high but track, precipitation types and amounts still quite uncertain

Snowy road with words "Christmas Storm" superimposed

Confidence remains high on a strong winter storm in the Midwest and Great Lakes region next week, but the important details on storm track, precipitation type and snow amounts remain quite uncertain, according to an “Area Forecast Discussion” that the northern Indiana office of the National Weather Service (NWS) issued early this morning.

Computer forecast models continue to “jump around with potential solutions,” writes meteorologist Sam Lashley.

As of this morning, Lashley expects mostly rain Monday night through Tuesday in his forecast area (northern Indiana, southern Lower Michigan and northwestern Ohio). Meteorologists remain uncertain about when and where that rain might change to snow and how much snow might fall, but as of this morning, snow is most likely Wednesday and Christmas Eve.

The “Hazardous Weather Outlook” that the northern Indiana NWS office issued this morning advises readers that the storm could impact holiday travel and that they should “pay attention to later forecasts as details become more clear.”

Good advice. You can always get information directly from the NWS website ( and as my personal time permits, I’ll continue to keep readers of this blog updated.

NWS forecast discussion addresses Christmas storm “hype”

Hype is already underway about a possible winter storm next week, writes meteorologist Sam Lashley of the northern Indiana office of the National Weather Service (NWS) in an “Area Forecast Discussion” (AFD) issued this morning. But “a lot of uncertainty remains with respect to the very important and critical details of when and where this storm will create impacts,” the AFD continues.

A “cautious but informative approach” is warranted, given the six- to seven-day time frame, Lashley writes. He expects “numerous critical changes and deviations” in computer forecasting model solutions with each model iteration over the next several days.

Broad agreement among models does provide higher than normal confidence that a substantial storm system will impact some part of the eastern continental United States by Christmas. That said, “Confidence remains below normal on important details, such as the track, precipitation type and amounts,” Lashley writes.

He concludes with, “Any snow that does fall by Christmas will certainly create travel issues and have significant impacts due to blowing and drifting.” This remains worthy of mention in NWS Hazardous Weather Outlooks, but “restraint should be exercised for now in the forecasts of track and snow amounts given little skill at this time range.”

Special Weather Statement issued December 17 at 2:52AM EST by NWS

View the full statement on the NWS website.