Friday, March 11, 2005

Breaking news: March temperatures today in DC area!

With no precipitation so far and therefore more sun than expected, temperatures are warming up more than we originally forecast. National was at 53 with a high overcast by 1pm, and it was in the lower 50's in most other places. Further south, it was 57 in Fredericksburg. With continued sun and a southwest wind ahead of a low-pressure area that was moving into western Pennsylvania at mid-morning, we will be close to the normal high for the date of 54, an unusual event this March. Around midnight last night, radar showed scattered areas of snow showers in the mountains of West Virginia and about as far east as Hagerstown in Maryland, but very little was reaching the ground. Hagerstown did report a trace of precipitation overnight. (This must be one of those "Discount Snow Storms" eBay was advertising over to the right last night.) Today, the nearest activity around 1pm is widely scattered rain showers in central Maryland and a bit east of I-81 in northern Virginia. The model forecasts have been consistently over-predicting precipitation for the DC area from this situation, but we still can't rule out the possibility of a shower of flurry later in the day. The most likely time for this would be late this afternoon or early evening.

The weekend
For the weekend, a mixture of clouds and sun with a slight chance of rain or snow showers should continue with colder temperatures, as described by Jason below.

The Weather Channel
I was living in Woodstock, NY in the early 80's when our local community antenna with about 10 channels was upgraded to a "real" cable system. The TV's and VCR's in those days didn't have digital tuners, so you had to manually tune in a channel to a particular button. I remember my excitement when I twisted the tiny knob to find all weather, all the time. Now, I have to agree with Jason that it's a lot less appealing. I hope I don't sound like I have stock in the company since this is my second mention of it here, but the answer to this (besides the Web, of course) is TiVo. (I don't; they have a great product but terrible financial performance.) By leaving the box tuned to that channel, you always have the most recent 30 minutes of content available. You can use fast-forward to get the approximately 5 minutes of useful content out of that in 5 minutes or less, and you can use pause on the radar loop if necessary. I find that this technique works quite well with CNBC also, if you don't care about the conventional wisdom regarding the latest oil price blip.

Editorial note: If you need basketball coverage and want to look more productive at work, the Post is running a blog from the MCI center. You can get to it here

Thursday, March 10, 2005

Mid-day update

A very weak trough of low pressure moved over the area this morning, bringing with it some light snow flurries, enough to whiten the ground in a few areas. Washington National reported light snow at 8am with a temperature of 28. Temperatures are a bit higher than yesterday at this time, in the mid 30's at noon and upper 30's at 1pm. Highs should be in the low 40's under partly cloudy skies.

As Josh explains below, the model predictions are bringing a low pressure area which was over Minnesota this morning southeastward and off the coast. This has the potential to give us some light precipitation on Friday and Friday night. We have been misled at times by the models recently, but both major U.S. models this morning were showing that temperatures in the lower half of the atmosphere will be cold enough for anything which does fall to be snow. As has been usual in the recent upper air flow pattern, the major storm development should be off the coast with most of the precipitation occurring in northern and eastern New England.

Broadcast news
Our friend Tony Pann of Channel 9 will be starting a weekly weather talk show beginning April 10 on WCBM 680 AM at 3pm.

Don't try this at home, kids
You wouldn't want to try this with WSSC water rates, but check out NPR's report yesterday on what you could do with industrial quantities of water, months of sub-freezing air, and perhaps a wee bit too much time on your hands in the long Alaskan winter.

Image: Ice sculpture from Alaskan Alpine Club, via NPR

Wednesday, March 9, 2005

Mid-day update

Today's menu
Momma Nature lost all track of the calendar down at the Weather Grill, so they've had to clean out the freezer by putting lots of winter leftovers on the menu. They were in such a rush that they didn't take the time to thaw all the ingredients; many meals were sent back to the kitchen yesterday. Today's lunch specials include more below-January-normal temperatures, and the breeze gusting over 20 mph makes it feel even colder. Around the area, temperatures were barely reaching the freezing mark at noon, heading for a high no more than the upper 30's. It's also very dry, with dewpoints in the single digits; without the wind, it would have been even colder last night than the official low of 20.

A bit of history
In the classic words of SCTV, our low pressure area from yesterday "blowed up real good" in the Gulf of Maine. The isobars are crowded so close together on this morning's weather map that it's a bit hard to read, but I think I see the digits "962" as the minimum pressure in mb. This is stronger than all except one of the 20 classic snowstorms from 1955-85 analyzed by Kocin and Uccellini in their book "Snowstorms Along the Northeastern Coast of the United States". (I notice from the news at the link above that TVLand will be airing SCTV beginning March 18. If you're too young to have seen this before, stay up late, clear the space on your TiVo, do whatever it takes, you must watch. This just in from the Irony Dept: The blogger spell-check suggests "castoff" as an alternative to "SCTV".)

Contest faux pas
Our FROPA contest seems to have been a faux pas, since we don't have any entries. If we get some T-shirts printed up, will that help next time? It seemed like a good idea, but it didn't get reviewed by the quality control folks at the Weather Grill. Because of the dynamic nature of weather data and the Web, it's not that easy to find a verifiable record of 24-hour temperature changes. When I tried to check the recent history at the local high school, I got the message "Microsoft OLE DB Provider for ODBC Drivers error '80040e07' " Thank you, Mr. Bill! The nearby middle school came through, however. The biggest 24-hour temperature drop I found was at 1pm, just after the snow ended yesterday, when the temperature of 27.5 was a whopping 41.9 degrees below Monday's at the same time. There were 5 hours which had day-to-day temperature drops over 40 degrees. These temperature changes are much more characteristic of the Midwest than the East Coast.

Still hope for spring
Despite the latest antics of the Weather Grill kitchen crew, spring is still on the way. The first estimate of the peak for the cherry blossoms in Washington is April 4-9.

Monday, March 7, 2005

Mid-day: Springing back to winter

To paraphrase the poet, "What is so rare as a day in March?" In Washington so far this month, that would be an actual March day. Of the 7 March days including today, only one (yesterday) has had a high temperature which would be considered normal for any day in March. By late morning today, temperatures around the DC area were already at 60 or higher in many locations with generally south winds. The long-term average high for the last day of the month is 61. At noon, Washington National was at 63, and by 1pm, most reporting stations were in the upper 60's, with 70 in a couple of places. Today's record high of 77 doesn't look in jeopardy, but it does happen to be equal to the lowest record high for any day in March.

Momma Nature finally shut the freezer door at the Weather Grill over the weekend, but it's going to be flying right off the hinges this week. As Jason explains below, winter temperatures will be back by mid-day tomorrow. As Josh showed in the 10-day outlook on Thursday, this is caused by a strong high-pressure ridge at upper levels in the atmosphere over western North America, along with a strong trough developing over the eastern part of the continent. Under the ridge, California is drying out from their recent near-record rains. Under the trough, as it deepens, cold air will move steadily southward from Canada to the East Coast. This pattern also has a lot of energy associated with it, so there will some storm activity at the surface, although the Weather Grill chefs are still trying to decide exactly where and when to serve the spiciest dishes later in the week. On this morning's weather map, this is reflected in a strengthening low-pressure area centered over Michigan with a cold front extending southward to Texas.

We tend to focus our attention upstream (westward), since that's where our weather comes from, but the Northern Hemisphere circulation pattern continues to the east after our weather leaves us. The high-amplitude pattern, with a large north/south component of the upper-level wind direction, continues around the rest of the hemisphere. There is another strong ridge over the Atlantic and a corresponding trough over Europe, which accounts for the cold weather over there. The "Beeb" has posted slide shows of the snow and cold in Britain and the Continent.

Image: An abandoned car covered in snow in Kent, southern England, from BBC

Seasonal Outlook

Latest seasonal forecast: Click here.

Latest 3-month temperature outlook from Climate Prediction Center/NWS/NOAA.