Tag: Winter

Here it is 1:00 in the morning, I’m not working until Sunday, but I’m sitting in the family room with my laptop watching animated forecast maps and studying charts. I am so nerdy. This is what I was meant to do.

The Saturday storm is a fast moving clipper. No one needs to go nuts. Most roads should be good-to-go by Saturday night.

I’m currently looking closely at three models: NAM, GFS and HRRR. They’re all similar in their solution. All snow.

Exact accumulations forecasts are never spot on. Mostly we’ll see 2-4″ statewide (and by 2-4″ I mean 1-5″). In other words enough you won’t want to drive in it, but not enough to leave a lasting impression.

The storm will pass south of us. The bulk of the snow should fall between 7:00 AM and 4:00 PM on the shoreline and 9:00 AM and 3:00 PM inland.

It will be cold. Some inland spots might stay in the teens though most will be in the low twenties. On the shore it will be closer to 30&#176.

Since I’ve been doing the Premier Subaru ads I’ve been promising I’d get some snow driving video. Tomorrow’s the day.

What looked like nothing on my weather maps last night looks closer to something today. This isn’t a major shot of winter weather coming, but enough to care about. My mind has switched to obsessive mode. I’m currently antisocial!

It is cold. Two lows, one over Canada the other Texas, will combine to produce a single low somewhere east of Chicago by tomorrow morning. The positioning of the resultant low is critical because it will be controlling both moisture and temperature.

The mercury will rise tonight. That’s what I’m talking about as far as temperature control is concerned. The low will be pulling in warmer air from the south.

Meanwhile moisture is also on-the-way. Statewide it looks like that will be snow at the start. Not a lot. Not for long. Some areas could see an inch. Most won’t.

As the warmer air arrives the snow goes to sleet and mixed precipitation and then rain.

Here’s the problem. The ground will stay cold longer than the air. Icy/slippery conditions are probable as whatever falls at any given moment freezes on contact. The farther north and the higher the elevation the more likely this is.

Can this be treated? Absolutely. This type of lightweight storm seems the poster child for chemical treatment! Of course that’s never 100% effective.

All of this will take place between 9:00 PM and 4:00 AM. By wake-up time the slippery part of the storm will be finished. There’s rain coming later, but nothing worrisome.

There surely will be some scattered delays. Closings probably aren’t warranted. Unfortunately, like predicting baseball rain outs there are lots of hidden factors at work. How the superintendents make up their minds is a mystery to me.

It’s December. We’re in New England. It snows. I understand. I’m still not happy about the forecast for Thursday!

When I looked at the 18Z GFS yesterday afternoon the probability for snow Thursday was fairly obvious. A low pressure system will be south of us moving east. Moisture from the low will be pressing up against cold air.

The 00Z run came in just before I went on-the-air at 11:00 PM. The snow was gone!

Of course that’s the problem. A few days out a small shift in trajectory spells the difference between hit and miss. You hope for the models to come into agreement… and then you just pray.

Snow’s back in the GFS today. It’s also showing up in the ECMWF, aka “the European.”

Typically this kind of scenario produces a light-to-moderate snow in less than twelve hours. It would be enough to close schools, but most people will be tempted to go to work.

I’m planning on rigging some cameras in my Subaru Legacy just in case Premier wants to do a “proof-of-performance” ad sometime.

Rachel and I discussed snow before she went on today. I told her I was glad not to be on the forecast at four. She said the same for tonight at 10 and 11.

There will be a lot of number crunching going on over the next few days. Pieces of the forecast will surely change.

If you absolutely, positively need something done by Thursday as of now you should probably plan to do it Wednesday!

I spent the evening in the mancave with my friend Rick. No coat. I’m mancave ready… even outside!

I called Stef in Southern California as I made my way home. Big mistake! It was cold and mainly rain at Rick’s. That was as far as you could get from her weather.

“I wore a short sleeve shirt and flip flops to work,” she said.

Children have been written out of wills for less! Don’t test me child.

This afternoon the weather station on the USC Campus near Downtown Los Angeles read 91&#176 with a dew point of 50&#176.

Our 3:00 AM readings have just arrived:

CITY SKY/WX TMP DP RH WIND PRES REMARKS
BRADLEY INTL LGT SNOW 33 31 92 N12 29.60F FOG WCI 24
HARTFORD LGT SNOW 35 32 88 N12 29.58F FOG WCI 27
DANBURY LGT RAIN 34 32 92 NE6 29.57F WCI 29
WTRBRY/OXFORD CLOUDY 32 28 86 NE15G21 29.56F WCI 22
BRIDGEPORT RAIN 36 32 85 NE12 29.56F WCI 28
MERIDEN LGT RAIN 34 31 88 N8 29.55F WCI 27
NEW HAVEN LGT RAIN 36 33 89 N13 29.54F WCI 27
CHESTER NOT AVBL
GROTON LGT RAIN 36 32 85 NE13 29.52F WCI 27
WILLIMANTIC LGT RAIN 34 32 92 NE7 29.58F WCI 28

A few quick notes. Waterbury/Oxford’s weather sensors haven’t worked for the last few years. Cloudy doesn’t mean there’s no precipitation at OXC (the airport’s identifier).

Chester’s weather site (SNC) hasn’t been dependable for months. For a while it was reporting a higher dew point than temperature. That’s a physical impossibility.

I walked downstairs and opened the door a half hour ago. It looked like rain, but sounded like sleet was mixed in. I decided listening was observation enough.

It’s a little tough to see what’s going on via the DOT traffic cameras. They’re not well lit! This shot from West Hartford looks to have some icy slush on the shoulder. There’s probably a little, not much, on the road surface too.

At this hour radar shows more precipitation to come. My earlier call on who gets rain, slush or snow stands.

Though temperatures on the ground will remain fairly steady the prediction at cloud level is for falling temps. That means more snow than rain in those areas already seeing snow. Of course the ground is wet. It will take a lot of snow to overcome the puddles and cover the roads.

I’m sticking to my guns on Litchfield County and far Northern Connecticut being the only places where there will be a real weather impact over the next few hours.

One more note before I go. Be careful with the radar during the winter! If there’s sleet falling through the clouds the returns will look stronger than they should. Sleet is very reflective to radar beams. You have to develop an eye to see it, but there is some “bright banding” in evidence tonight.

It would be nice if this was the end of winter, wouldn’t it?

As of this afternoon there is a new model to look at. The storm has moved into the realm of the RUC (Rapid Update Cycle). That’s a short term mdel run every hour. It is in agreement with the NAM and GFS which both seem a little warmer than last night.

What this means is a shift of the rain/snow line a little farther north. Not much, but at this stage of the game even 10 miles is a big deal. A combination of rain and snow usually means we only deal with the rain.

For most locations this storm will be a minor inconvenience. Accumulations should be slushy if there’s any snow to accumulate at all. I won’t be surprise to see Hartford, Middletown, and Storrs with no need for plows. On the shoreline you’re off-the-hook.

It’s still cold and wet enough for significant snow in the hills and some other areas close to the Massachusetts border. I’ll be looking for pretty pictures from friends in Warren and Kent.

This is such a guy thing. We just don’t want to commit! Oh, what the heck. I will anyway. I think I have a reasonable handle on the storm which will be over Connecticut Thursday into Friday.

I posted a little note on Facebook and Twitter Wednesday evening.

I want to have more time to digest it and the GFS, but it seems the 00z NAM is a little warmer. The NAM had been the snowier model

The little animation at the top of this entry doesn’t show perfect alignment between the GFS and NAM, but they’re now pretty close! By allowing the low pressure center to move farther north the NAM is hinting at more rain, less snow.

This is Connecticut. We don’t get weather, we get samples! That will be true with this system. Everyone will get a little of everything, but the farther south and east you are the larger percentage of what you get will be rain.

The best way to look at it is by drawing a diagonal between Union in the north and Greenwich in the southwest. South of that line will be mostly rain. North of the line will be mostly snow.

Of course it’s not that simple!

Rain is the mortal enemy of snow! Rain on the ground will usually ‘eat’ snow as it falls. That’s why I’ve divided the map at the bottom of this entry into three parts&#185.

Hartford, Waterbury, Danbury, Colchester, Middletown and Storrs will get a few wet and slushy inches. If you only look at the snow falling by your window you’ll think there should be more on the ground! Most of that central slice of the state will see light snow, then rain, sleet or a wintry mix, then back to snow late Thursday night.

Closer to the shore there probably won’t be any accumulation at all. It’s still going to be a stinker of a day–cold and wet!

In the higher elevations of the Northwest Hills I wouldn’t be surprised to see some foot plus accumulations. Most areas will get significantly less.

It will be sloppy at wakeup Friday morning. Some areas will see delays or closings. Most places will not.

On a night like this I might have gotten as much as three minutes to deliver the weather on TV. I think you’re getting more meat here.

&#185 – It’s times like these when I miss the computers we used to display the weather on television.

Nearly all our software came from Weather Central in Madison, WI. If there’s a way to do their graphical magic from home I haven’t figured it out… and I’m pretty resourceful where this stuff is concerned.

I have a new found respect for something I often took for granted.

You humored me yesterday by staring at the weather map I posted. I’ll press my luck again this time with four maps! This is a comparison of two different models, the NAM and the GFS, and how they depict rain versus snow.

These are the most commonly used weather models. They’re in agreement right now about as much as the Republicans and Democrats are!

Here’s the setup. Everything you see on the left map is rain. Everything on the right map is snow. An arrow on each map points to Connecticut.

Look closely and you’ll see the GFS favoring the left map over Connecticut. The NAM favors the right.

The exact numbers aren’t all that important now because I can guarantee they’re not accurate! Look instead at the colors. The hotter they are the more precipitation is predicted.

The GFS is forecasting a heavy rain event for nearly all of Connecticut. The NAM is much snowier with rain mixing in close to the shoreline.

Where they both agree is in accelerating the precipitation. It now looks like we’ll see the first of it (whatever it is) sometime Thursday afternoon. The NAM has everything ending around rush hour Friday. The GFS is a little slower and holds the rain into Friday afternoon.

Do you see why this stuff frustrates me so? Sure, we don’t miss them like ’78, but there’s still a lot of hemming and hawing on my part when I’d rather be firm.

Since we’re so much closer to the even my method of forecasting will change a little. I’ll start paying closer attention to how the models were initialized. That means I’ll check to see if that data fed into the computers as they started their work matches the real world conditions. Because of the methods used to create the initial conditions they don’t always!

I’ll keep you up-to-date.

It’s nice to be in the saddle again.

This entry was originally labeled Saturday’s storm even though the content made it clear it was Friday’s! I have fixed the title. Not my day.

At this point the storm due for early Friday is showing less stability than Charlie Sheen! What looked like snow early Monday and rain late Monday has reverted to its evil ways. The guidance points to snow again… and its arrival now as early as Thursday night! I won’t be surprised if the scenario changes again.

In order to better explain what meteorologists look at I’ve created a small animated map (above). These things are always confusing to people who don’t deal with them on a daily basis so let me lay out what you’re seeing.

First, there is a map under there! It’s hidden because it’s overlayed with indicators for precipitation, sea level pressure and atmospheric thickness. To make it easier I’ve thrown in an arrow pointing to Connecticut (its tip is pretty close to New Haven).

Second, the two maps in the animation both correspond to a forecast for 2:00 PM Friday, One was produced last night, the other this morning.

Third, the center of the storm is the center of the circular lines and marked by the letter “L.” The center of the storm is where the barometric pressure is lowest.

OK? I haven’t lost you yet, right?

What’s the difference between the maps? Last night the center of the low was over Northcentral New Jersey. Today it’s pushed just east of Cape Cod.

Because this storm has much colder air on its west side moving the center farther east chills the atmosphere above us! That’s why the chance for snow is now greater.

I still expect rain to mix in on the shoreline and much of this snow to be heavy and wet. If (and that’s the operative word)… if this forecast holds much of Connecticut will see six inches of snow or more.

As we move forward the models should begin to stabilize. We’ll also start having access to more models that don’t even attempt to forecast this far in the future.

Is there utility in a forecast this likely to change? Yes! Knowing there’s a reasonable chance for a storm allows people to have alternate plans. On the other hand it’s much too early to cancel or change your plans.

These were the work days I hated. I don’t want to disappoint.

I wish there was a way to be absolutely sure and know the forecast would never change. Dream on.