baltimoresun.com

« Moon, Spica and Saturn align late tonight | Main | Washington's birthday is when you say it is. »

February 21, 2011

Overnight snow could drop 5-8 inches

UPDATE 3:10 p.m.: The Winter Storm Watch is now a warning for Carroll; Central and Eastern Allegany; Extreme Western Allegany; Frederick; Harford; Northern Baltimore; Washington.

"WINTER STORM WARNING IN EFFECT FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY...  PRECIPITATION TYPE...BRIEF PERIOD OF SLEET...THEN SNOW WHICH WILL BE HEAVY AT TIMES. * ACCUMULATIONS...5 TO 8 INCHES OF SNOW. * WINTRY MIX OF SLEET AND RAIN WILL BEGIN EARLY THIS EVENING...CHANGING OVER TO ALL SNOW LATE THIS EVENING. THE SNOW WILL CONTINUE INTO THE EARLY MORNING...BECOMING HEAVIEST BETWEEN MIDNIGHT AND 4 AM."

And the advisory for Anne Arundel; Howard; Montgomery; Southern Baltimore has been upgraded to a warning. 

"WINTER STORM WARNING IN EFFECT FROM 9 PM THIS EVENING TO 7 AM EST TUESDAY... PRECIPITATION TYPE...BRIEF PERIOD OF SLEET...CHANGING TO SNOW AROUND MIDNIGHT WHICH WILL BE HEAVY AT TIMES OVERNIGHT. * ACCUMULATIONS...4 TO 8 INCHES OF SNOW. WITHIN THIS RANGE...THE HIGHER AMOUNTS WILL BE IN THE NORTHERN PART OF THESE COUNTIES."

UPDATE, 10 a.m.: A Winter Storm Watch has been issued beginning at 9 p.m. for the northern counties, including Frederick, Carroll, northern Baltimore and Harford counties. Forecasters say 4 to 6 inches of snow are possible overnight in the Watch area.

"A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT
SNOW AND SLEET ACCUMULATIONS THAT MAY IMPACT TRAVEL. CONTINUE TO
MONITOR THE LATEST FORECASTS."

Here's the updated (clickable) forecast snow map:

Weather Service had predicted 1 to 3 inches of snow overnight at BWI-Marshall Airport as a pair of low-pressure systems move through the region. The precipitation will start as rain, become mixed in the wee hours of Tuesday as temperatures drop behind the first low, then change to snow before ending during the rush hour.

Here's how Eric the Red saw it last night:

"Over the weekend, models did everything imaginable... no storm, all rain, all snow, and now back to a north to south changeover.  I think I'll stick with 2 to 5" on grassy surfaces for central and northern MD... and once you get down toward Annapolis and DC, the question of when (and if) the changeover occurs becomes fuzzier.  I would suspect that unless the cold air really pushes in fast, locales south of Baltimore will struggle to get more than an inch or two."

Here, on the jump, is how he sees it this afternoon:

"It appears the near-perfect timing necessary for a good snowfall tonight will in fact play out, so I think I better up the totals... esp across nrn MD.  For much of central and northern MD, 4 to 8 inches of snow are liklely tonight.  Totals will be lower farther south into northern VA, but the changeover to snow (if any sleet or rain is falling initially) should be quick enuf to get even the southern portions of the region a decent 2-4" snowfall.

"The models are in excellent agreement that a storm system coming in from the west will collide with the timely arrival of cold air from the north.  I was figuring that recent warmth and time of year would cut into snow totals, but there are a couple things at play here that will make that original thought null and void.  First, altho it may not feel like it just yet, plenty of cold air is pushing south out of New England into the Mid Atlantic...and temps at the surface are expected to plunge into the low to mid 20s as the snow arrives.  That will up the liquid-to-snow ratio.  Also, this event will be at night, removing solar insolation from the equation. 

"Timing... snow or mixed precip will arrive from the west between 7 and 10 pm.  What ever sleet or rain there is will quickly change to snow as evaporative cooling kicks in.  A period of heavy snow is likely across central and northern MD late tonight, and snow will linger into the morning commute.  Temps tomorrow will not get above freezing, so this will definitely stick around for a little while.

"I should note that I am being conservative here.  If the WRF has this right, then snowfall will be in the 7 to 14" range across central and nrn MD, due to higher pcp totals and cold air pushing up the snow ratio.  The RSM would suggest 8 to 16" for the same reasons.  The GFS is a bit lower (and the model I'm leaning on for this one), with a liquid total of ~ 0.50"... and that would get us in the 4 to 8" range.  Anyway, here we go..."

Posted by Frank Roylance at 8:29 AM | | Comments (30)
Categories: Forecasts
        

Comments

Wait a minute, the article says predicting 1-3 inches of snow at BWI - which is in Anne Arundel County. But the update at 10 a.m. in the same article does not mention AA Co.

FR: Because the forecast has not changed for BWI and Arundel. Still 1-3"

Frank,
I presume you meant to write the precipitation will start as rain, then change over to snow as temperatures drop.

FR: Yes, I did. Fixed. Thanks.

The latest (noon) forecast from NWS has northern Carroll County in the 5-9 inch range now, with about 7 inches according to the Sterling forecast map.

FR: Trying to keep up while having a life (Supposed to be off today)

Said it before and I'll say it again....weathermen have the best job. Coming to work this am Tony Pann said 1 to 2 inches at most. 5 hours later 4-8 (maybe as much as 14 according to Eric) Must be nice to have no idea what you are doing and still have jobs. How do you explain 1 forecast and then 5 hours they are caling for 7 times as much (potentially) as earlier?

Thank you for the updates on your day off, Frank!

The potential in this storm seems to be ramping up quickly!

I'm predicting 1-16 inches. Bam!! I could get the hang of this prediction stuff.

"How do you explain 1 forecast and then 5 hours they are caling" (sic) "for 7 times as much (potentially) as earlier?"

Easy- same amount of precipitation, but now more as snow and less as rain.

@Steve, I'm no meteorologist, but I do know that a bachelors degree in meterology at my college requires 4 semesters of calculus...it's not just a fun guessing game, a lot of work goes into predicting an unpredictable environment

I thought by now everyone would know that Cecil Country is part of Maryland I guess not !

If we wind up getting 6+ inches of snow, somebody at NWS needs to explain why it took them so damn long to post even a winter storm watch. At least post a wsw, so that people can be made a aware of the potential--cancel it if/when things change. I'll never understand why they're so damn conservative about forecasting winter storms because they take more heat when they're wrong low

It's snow. Get over it people.

Thank you Kerrie - If the people who bash meteorologists knew the complexity and nearly endless variables that need to accounted for in a weather prediction, I don't think they'd be so quick to criticize. The mathematics alone is beyond most people.

Pmeh. I'll believe it when I see it. How's that for attitude! Hrumph!

If you paid attention (and checked the right sources), there have been mets that have been predicting this for at least 48 hours. I would recommend that you stop listening to Marty Bass & Tony Pann and start following abc2 new's Justin Berk. He's been much more accurate than any other local mets. Additionally, if you really wanted information, go to Henry Margusity's Fan Book page on facebook. There's lots of model discussions happening in real time.

Frank Roylance- Maryland's internet weather answer to 80's Pat Sajak, comes in soft on his daily weather prediction. While his models call for 8 inches of snow, Accu Maryland models put this snow at 2-5" of base accumulation with a sleet into the later hours this evening. While Royalnce and his models play it safe my prediction factors in Appalachian wind patterns and the overall development and structure of this storm.

I do give Roylance credit for his research and with respect given inform our readers that this pump and dump that Roylance penned is nothing more then a whimsical trip into the world of weather. The fairytale dreams of 8 inches suggested by Roylance and his models are wrong. There is a 30% chance we get 8 inches tonight and there is also a 30% chance we get 2 inches. And while the fire power is there to dump 8 inches, I dont expect temperatures to remain low for long.

Don't plan on having off in the morning.
-AM

FR: I guess we'll all see in the morning. BTW, "Roylance" has no models, makes no predictions. I report what the NWS and a selection of others are saying. When they change their tune, I report it. I have no idea what your Pat Sajak crack means. Wish I had his dough.

listen people. its only going to snow for a couple hours. you are all going to work.

follow my blog. i predict the weather better then Roylance

http://accumaryland.blogspot.com/

Roylance- why aren't you publishing my comments. I didn't know the Sun censored

FR: If they aren't spam, libelous or obscene, I publish them when I see them. This is not a 24/7 gig.

@John, The reason that the map that was posted doesn't show Cecil County or the Shore is that this is from NWS for Baltimore and Washington. Cecil Co. and the Shore get their updates from Mount Holly, NJ, which isn't included on that map

Laughing at Accu Weathers claims to have "weather models." Do you know what such a thing is?

FR: Weather models are complex mathematical computer programs, running on supercomputers, that take into account the best science on atmospheric physics, the latest observations on the ground and in the atmosphere, and data on the past behavior of weather systems under similar circumstances. There are quite a number of them, and all meteorologists (not just AccuWeather) consult them, add their experience, training and best judgement to sort through the models' sometimes divergent projections, and issue forecasts hours, or days in advance.

Geez People get over yourselves.

Frank gleans what he posts here from many sources and yes those sources are all over the place many times.

He is a Journalist (A Fine One) reporting weather. He happens to have a grasp of weather by living and breathing it most of the day.

Does that make him infallible or conversely fallible.

Yes it does just like everyone else.

You know it all's rarely come back and post when you miss something but I can tell you Frank will be back tomorrow writing and the next day and the next as long as he has the privilege to do so.

If you want predictable weather I suggest you move someone more boring.

I happen to like weather that throws curves so I will stay right here in Baltimore and continue to read this blog happily.

Fran In Baltimore

Hey, an 8 inch snow this late in the game will bring me a lot closer to my guess for snow totals for the year!

Just when you thought it was safe to put the snow shovel away....

FR: Like I said, mine's still on the porch.

So, which model has (historically) been more accurate for the Baltimore area, WRF, RSM, or GFS?

Laughing At "AccuMaryland"

I just wasted 2 mins of my life going to that "Informative" blog of yours.

Lobbing a snowball at you .. A nice icy one.

Fran In Baltimore

why is there a line dividing Baltimore county? (just north of the Beltway)

More snow please : ) !

But still have to go to work in am : ((

FR: Latitude, elevation and distance from the bay give northern Baltimore County a colder climate, so the NWS divides its forecast.

Ha ha! I was being cantankerous before on purpose because being skeptical about snowfall in Baltimore actually makes it snow more! And it WORKED! And I did it because it we get 8" I will be in very fine position for the snowfall prediction contest!

So I guess what I mean to say is that it is NOT snowing now and we will get MINIMAL accumulation IF it ever starts to snow tonight, which is UNLIKELY.

P.S. Don't be a jerk to Frank. For serious.

The line divides the Hereford zone, where people with septic systems vote against O'Malley, and the high density zoning area South of the Gunpower River, where his allies illegally dump sewage until fined nearly a billion dollars by the EPA.

No, I'm not making any of that up.

Thank you for updating on your day off!

I have to aggregate the forecasts, similar to you, but I have just one location to keep an eye on and my readership is 6 people.

I point people to your blog when they want an easy to read forecast which explains what and why something is happening, without all the hype.

And your space updates are also a big bonus! Regardless of it being cloudy or clear, you keep me looking up!

Thank you!

i appreciate all the love. whats wrong with keeping Roylance honest?
http://accumaryland.blogspot.com/

I love how the snow stops at the Susquehanna. I live in Cecil - I guess I won't have to shovel. Oh - and the info about Cecil being covered by Mt Holly? Not quite. Their forecast may mention northeastern MD, but their maps always stop at DE.

People only remember what fortune tellers get right and not what they get wrong. It's just the opposite with weather forecasters- no one remembers the times they get it right, only the times they miss it. Frank and Eric the Red helped me avoid an overnight on the JFX in my car this winter. Thanks again Frank and Eric.

Post a comment

All comments must be approved by the blog author. Please do not resubmit comments if they do not immediately appear. You are not required to use your full name when posting, but you should use a real e-mail address. Comments may be republished in print, but we will not publish your e-mail address. Our full Terms of Service are available here.

Verification (needed to reduce spam):

About Frank Roylance
This site is the Maryland Weather archive. The current Maryland Weather blog can be found here.
Frank Roylance is a reporter for The Baltimore Sun. He came to Baltimore from New Bedford, Mass. in 1980 to join the old Evening Sun. He moved to the morning Sun when the papers merged in 1992, and has spent most of his time since covering science, including astronomy and the weather. One of The Baltimore Sun's first online Web logs, the Weather Blog debuted in October 2004. In June 2006 Frank also began writing comments on local weather and stargazing for The Baltimore Sun's print Weather Page. Frank also answers readers’ weather queries for the newspaper and the blog. Frank Roylance retired in October 2011. Maryland Weather is now being updated by members of The Baltimore Sun staff
-- ADVERTISEMENT --

Sign up for FREE weather alerts*
Get free Baltimore Sun mobile alerts
Sign up for weather text alerts
SKY NOTES WEATHER

Returning user? Update preferences.
Sign up for more Sun text alerts
*Standard message and data rates apply. Click here for Frequently Asked Questions.
Maryland Weather Center


Area Weather Stations
Resources and Sun coverage
• Weather news

• Readers' photos

• Data from the The Sun's weather station

• 2011 stargazers' calendar

• Become a backyard astronomer in five simple steps

• Baltimore Weather Archive
Daily airport weather data for Baltimore from 1948 to today

• National Weather Service:
Sterling Forecast Office

• Capital Weather Gang:
Washington Post weather blog

• CoCoRaHS:
Community Collaborative Rain, Hail and Snow Network. Local observations by volunteers

• Weather Bug:
Webcams across the state

• National Data Buoy Center:
Weather and ocean data from bay and ocean buoys

• U.S. Drought Monitor:
Weekly maps of drought conditions in the U.S.

• USGS Earthquake Hazards Program:
Real-time data on earthquakes

• Water data:
From the USGS, Maryland

• National Hurricane Center

• Air Now:
Government site for air quality information

• NWS Climate Prediction Center:
Long-term and seasonal forecasts

• U.S. Climate at a Glance:
NOAA interactive site for past climate data, national, state and city

• Clear Sky Clock:
Clear sky alerts for stargazers

• NASA TV:
Watch NASA TV

• Hubblesite:
Home page for Hubble Space Telescope

• Heavens Above:
Everything for the backyard stargazer, tailored to your location

• NASA Eclipse Home Page:
Centuries of eclipse predictions

• Cruise Critic: Hurricane Zone:
Check to see how hurricanes may affect your cruise schedule

• Warming World:
NASA explains the science of climate change with articles, videos, “data visualizations,” and space-based imagery.

• What on Earth:
NASA blog on current research at the space agency.
Most Recent Comments
Blog updates
Recent updates to baltimoresun.com news blogs
 Subscribe to this feed
Charm City Current
Stay connected