Monday, February 2, 2004

MON 2/2 EARLY EVENING UPDATE: “YOU WANT THE TRUTH… YOU CAN’T HANDLE THE TRUTH.”
- Jack Nicholson, A Few Good Men

The truth is... this storm is coming, but you won't see any evidence of it until very early in the morning. If you stay up late watching out your window, there will be nothing to see for hours yet. Now, for all you in schoolyard land nervous about tomorrow, let me give you some reassurance as to why BCPS and possibly HCPS will be closed. My apologies to my customers in Philly... you will be mostly freezing rain and rain with maybe a touch of snow. Anyone above the Mason-Dixon line is not considered in these comments below. The State College and Altoona folks will be the big winners... as the earlier forecast holds firm... 6 to 9 inches with up to 12 in some areas.

Yes, I know, I know…. All the Baltimore TV forecasters are saying “all rain, all rain.” But there are so many errors in what I’ve seen on the 5:00 PM News that I am just beside myself. With all due respect to Norm (ABC2 News) and Marty (CBS WZJ) , they know you can't make knee-jerk changes in your forecast based on observations of just a few hours. So let me reconvince you that the forecast on this site will hold true.

Allow me to clarify some of the errors you have seen on the evening news in Baltimore:

1. A LOW PRESSURE SYSTEM WILL NOT BE TRACKING OVER OR ANYWHERE NEAR BALTIMORE. ABC2 News has a low passing OVER Baltimore from the west, while WJZ has one traveling up the Carolinas, through Virginia, and right over Baltimore from the south. NEITHER ARE GOING TO HAPPEN. The PHL and BAL NWS Offices expects the low to move a little farther offshore than the models are projecting. I don’t know what computer models the TV guys are are looking at. The NWS has clearly pegged the Ohio Valley low to move into the Great Lakes, and a secondary low will develop somewhere along the Carolinas. In fact, as of 7:00 pm, the NWS has shown the low to have developed off the South Carolina coast, as expected.

2. KNOW YOUR TEMPERATURES. ABC2 is calling for a low of 23, but is saying a mostly rain event. This kind of generalized forecast is completely ignoring the fact that the onset of precipitation will occur just before rush hour. If the air temperature is 23, road surfaces, bridges and overpasses will be well below freezing. Norm Lewis says the bulk of the rain will be after 9 AM… but if you have considerable sleet and freezing rain for several hours before that, it will make for a disastrous morning commute. And he says the kids will have a couple hour delay tomorrow. However, BCPS has two windows in which to make the decision... 4 to 5 AM, when snow, sleet and freezing rain will be falling, and then around 7:00 AM. The temperatures are going to stay at or below freezing until at least 9 AM... too late for the road to improve for a delay.

3. COUNTER-CLOCKWISE FLOW. Remember a secondary low will develop off the coast at some point during this storm and this will draw in colder air due to return (counter-clockwise) flow. That alone argues any precip not starting as rain, and delaying the rain changeover until late morning.

4. WHO CARES ABOUT THE EAST WIND! The situation with this east wind business as described on the news will do nothing to scour out the cold air at the surface. This is a storm where it does not matter what is happening 1000 or even 500 feet above the surface. It is surface temperatures which will make the difference. The TV forecasters say that the east wind is bringing the dewpoint up…which will make for a rain situation. But remember… if the temperature is going DOWN, and the farther away the temp is from the dewpoint, the harder the atmosphere has to work lower the temp to the dewpoint. And the precip will begin falling in the upper levels as snow first. This causes “evaporative cooling.” As the precip falls, it brings the temperature down with it. Even the WJZ forecast is for snow and sleet in the early morning hours. That alone will tend to hold surface temperatures down.

5. THE FREEZING RAIN EFFECT. When the rain falls onto surfaces that are below freezing, the rain freezes on impact. This has the effect to KEEP the ground chilled as it becomes covered with ice. And with at least half of Baltimore County to experience widespread icing, that is another argument for schools being closed.

6. COLD AIR DAMMING. The departing high is what has provided the east wind, but this is not a warm moist wind because ocean and bay temperatures are the coolest they will be all year long. The bay is now so cold (barely 40 F in Central MD) that it has really no warming effect at all on the surrounding land, or the air of an approaching storm. AND... the NWS has just indicated that the High in New England is NOT moving out to sea as quickly as was once thought. That will serve to keep cold air in place over the northeast longer. The cold air in effect "dams up" along the east side of the Appalachians. You can plainly see evidence of this if you look at the radar on intellicast.com. It is a weird site indeed... we have heavy rain WEST of the Appalachians, and rain turning to mix and snow EAST of the mountains. That is clear proof of cold air damming.

Sorry this is so long, but it unnerves me when the public gets a TV forecast that is designed to only reassure them, and not give the real facts.

ENOUGH ALREADY....WHAT ABOUT SCHOOL?

Consider the following arguments for Baltimore County Schools being closed Tuesday...

1. The onset of snow, sleet and freezing rain by 4 AM will make the morning commute a mess. Even if it does not start until 6 AM, we will still have at least 3-4 hours of frozen precip. On untraveled roads, it will freeze on impact. And there is lots of moisture available with this storm.

2. The ground surface is below freezing, and for much of Baltimore County, that will make for very slippery roads. The northern half of the county is in a Winter Storm Warning, with a 1/4 to 1/2 inch of ice by Noon. And you think we'll have school?

3. The changeover to rain will not happen until after 9 AM... too late for a delay to be effective. That would mean buses start rolling at 7:30... at the height of the icing? Most areas of the county are still going to be pelted with sleet and freezing rain by then.

Howard County...it gets more iffy with you. I think a 2-hour delay is more likely. I wish you could join the club, but maybe we'll be pleasantly surprised coming morning.

That's all for tonight... I'm back on baby duty until we get her to sleep. Another update around 5:00 AM, where we find out if I have to prepare the world for bad news, or simply turn off the alarm.

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