Wednesday, February 29, 2012

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Leap Day 2012: Tornado Trouble

(Left- Current Tornado Watches; Right - Outlook to 7 AM Thu 3/1)

2:10 PM EST 2/29/12  An extensive set of Tornado Watches have been migrating from the Mid-Mississippi River Valley earlier today to the Ohio Valley into tonight. As Forecaster Kelton noted yesterday, dewpoints were expected to reach the high 50s low 60s before the frontal boundary moves through, giving plenty of fuel for severe storms today. 
  • The primary hazards, including tornadoes, include hail to 1.5 inches in diameter, thunderstorm wind gusts up to 75 mph and dangerous cloud to ground lightning.
OVER A DOZEN  Already, the NOAA Storm Prediction Center has received reports of over 12 tornadoes in the past 18 hours, as shown on the latest storm report graphic. Conditions for much of today will remain favorable for additional development, as evidenced on current NOAA water vapor imagery. Wind speeds at the surface will also be high, in the range of 20-25 knots with gusts higher. Strong winds aloft are mixing down to the surface, removing any capping layers as well as aiding in bringing moist air from the Gulf of Mexico.

ARE YOU THERE? If are in the Mid-West, let us know and have recorded photos or videos of this event, have your imagery featured right here for all to see. Our approach to weather is to provide locally-relevant reports generated by actual people in the communities where our readers reside. If you are in the Mid-West, and would like to become the "face of the place" for weather in your state on our us: 
(Photo credit: Forecaster Nic Roberson of High Point, North Carolina, April 27, 2011)

(Forecaster Kelton & Advisor Mr. Foot)
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Stay tuned for "Sun Fade" !?

9:15 AM EST 2/29/12 On this Leap Wednesday, there is another interesting astronomical phenomena that occurs to us Earthlings twice a year, every year. In 2012 it ironically happens to be slated for Leap Day, and it's called a "Sun Fade." Sources and references:

Every Spring and Fall, the Sun's alignment with the orbit of satellites can interfere with the signal received by ground stations. Even if you don't have a satellite (such as Dish or Direct TV), this interference impacts how signals reach local TV stations and cable companies. But, we want you to be well-informed in case your view of "The View" gets interrupted, so we offer some basics. 

NOAA Geostationary (GOES) Satellite 
What's a sun outage? A sun outage is an interruption in satellite signals caused by interference from solar radiation. The interference is caused when the sun is in direct line with a communication satellite and the sun's radiation overwhelms the satellite signal. The programming provider Cablevision has sent out a message to its customers notifying them of potential interference, as reported in this article published earlier this week.

How is TV viewing affected? During this time, you may experience interference with picture quality and sound when watching television. Sun outages do not affect internet or phone service. 

When do outages occur? This year, the Sun Fade or Outage is expected between today, February 29th and March 8th during the times listed in the graphic posted above.

How long does it last? Interruption in TV service due to sun outages can last up to several minutes a day.

However, Facebook and the Internet should be alive and well... so if your TV flickers a bit, post a comment here and let us know if you see evidence of this unique phenomena today! 

(AMS/CBM Meteorologist Justin Berk and CEO/Lead Advisor Rich Foot)

Tuesday, February 28, 2012

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"A wild wind blowing..."
- Lyrics by Cold Play

11:25 AM EST 2/28/12 (Southeast Forecaster Kelton Halbert*) 
Severe Thunderstorms are expected early Wednesday afternoon and into the evening as a cold front approaches the Southeast from the West. Current indicators are that surface and winds slightly above the surface do not look to be conductive for strong wind shear. Therefore, the tornado risk is currently not as high as in previous events so far this year.

OVERVIEW This event should produce mainly squall lines through the day Wednesday in the Southeast, possibly extending into the southern Ohio Valley. The anticipated hazards and timing from this system:
  • Damaging straight-line winds are the main threat, with some hail possible. Tornadoes are also possible.
  • This system may impact the Southeast early to mid afternoon, starting in Tennessee first early in the afternoon. It will then progress into Mississippi and Alabama, then into the Carolinas in the overnight hours. 

ANALYSIS Right now, weather models and forecasters are in good agreement about the timing of this event. However, the amount of heat and daylight hours will dictate just how severe things get. If the event delays, we could see the risk area shift to the West. If it happens too fast, the risk area would shift to the East. Timing is critical with this one!

Dewpoints are expected to reach the high 50s low 60s before the frontal boundary moves through, giving plenty of fuel for severe storms. This is evidenced on the current NOAA water vapor as shown above. Wind speeds at the surface will also be high, in the range of 20-25 knots with gusts higher. Strong winds aloft will mix down to the surface, aiding in removing any capping layers as well as aiding in bringing moist air from the gulf.

Once this clears out, there is another rumor of severe weather on Friday, and we will keep you posted! As you can see, there'll be a "wild wind blowing."

(*Forecaster Kelton is a high school junior in Nashville, Tennessee, and recently attended the 2012 meeting of the American Meteorological Society in New Orleans with our team. Kelton is a 2011 graduate of the NOAA- and NSF-funded Careers Camp program operated by the National Center for Atmospheric Science headquartered at Howard University in Washington, D.C. He attended the July 2011 camp program at Mississippi's Jackson State University and operates a technical analysis forecast website called "Tempest Chasing" )

Monday, February 27, 2012

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While we've been warm...
...they've been cold. 

5:30 PM EST 2/27/12 Though Blizzard Watches and Winter Storm Warnings are posted for the Northern Plains today, the overall pattern for much of North America has been a milder, drier winter with above-normal temperatures. This week, places along the East coast may once again aim for 60 F or higher ahead of a cold front. Contrast with record-breaking frigid temperatures in much of Europe recently, (as low as -22 F) with snow to Rome and Northern Africa. It's no surprise that inquiring minds are repeating a line from Jake Gyllenhall in Day After Tomorrow "What is going on out there, Dad?!?" 

This excellent report from the Physics website details the background behind why we've been warm, while they've been cold. A few talking points we'd like to offer in support of the article.
  • Oh, the NAO: Winter 2011-12 in North America has been strongly influenced by a moderate La Nina, in combination with a resoundingly positive "North Atlantic Oscillation" (NAO). This climate teleconnection, as shown in the screen cap above, has shown generally up values since well before winter. When this index is positive, intrusions of Arctic air into the Eastern U.S. are short-lived and infrequent.  Where did all the cold air go? (insert big, devious smile here...)
  • Argh, that AO: Now compare the positive trend in the NAO this winter to the wild swings recent negative trends in the Arctic Oscillation. As noted in the article, one factor may have been that "The tight  that had bottled up the cold arctic air in the beginning of winter suddenly weakened. Cold air swept out of Siberia and invaded Europe and the Far East. Now the vortex is weakening. With 'the AO Index going negative,' as an expert or weather-nerd* might put it,  escapes from that whirlpool and heads southward, resulting in the killing extremes now plaguing the other half of the planet." (
THE ELEVATOR VERSION, PLEASE... If it's much colder (or warmer) than normal where you are, chances are high someone else is also getting scammed out of their normal pattern in the opposite direction. Why? With at least three major climate indices on a rollercoaster ride this winter (La Nina, NAO and AO)'s safe to say that "Momma" (Mother Nature) isn't very happy. 

And if Momma's not happy...  

(Forecasters Foot; Contributors Mike N., Jason M. and Advisor Dr. Pete Winstead) 

Friday, February 24, 2012

Overview of U.S. Team Forecasts
(Content from our Facebook forecast pages is reposted in the links above
for easier access in schools and offices during the business day.)

Roundup of forecasts by region 
(Links below direct to team forecast zones in Facebook.  Zones denoted 
with an asterisk (*) are operated independently by Affiliate Forecasters)

Pacific Northwest | Tri-Cities Weather(Southeast Washington)
Central Colorado | Cirrus Weather* (Kansas)

Metro Atlanta | Southern Georgia 
East Tennessee |

Winter Stormcast | Northern New England
Northeast Kingdom Weather* (Vermont)
Severe Weather | Winter Stormcast 
Central New York State | Metro New York
Three Rivers | Southeast PA | Central PA | Northeast PA 
Northern Bayshore
Potomac Ridge & Valley
Northern VA | Central VA | Tidewater VA
No comments:
"There's a storm front coming..."
- From the 1989 album Storm Front by Billy Joel (Youtube music video)

Current WSI Intellicast Radar Loops

5:20 PM EST 2/24/12 | Tornado Watches remain in effect for two regions: Watch # 38 for Southern/southeastern Maryland, central/eastern North Carolina, northeastern South Carolina, and central/eastern Virginia.
Watch # 37 is for southern South Carolina, southern Georgia and portions of northern Florida.
  • Both watches are in effect until 8PM. Destructive winds over 65 mph, small hail, and tornadoes will be possible in the stronger storms. 
  • Stay tuned to the NWS for any warnings that may be issued, remain alert for changing conditions, and seek shelter immediately if you suspect severe weather in your area. Forecasters Jason M., Mr. Foot)

11:25 AM EST 2/24/12 
TORNADO WATCHES IN THE MID-ATLANTIC... Large portions of the Southeast and the southern Mid-Atlantic are under a Tornado Watch until this afternoon or evening. The regional roundup at present:
  • Mid-Atlantic: Areas include central and southwest Virginia, southern West Virginia are under Tornado Watch # 36 until 4:00 PM.  
  • Southeast: Tornado Watch # 35 until 4:00 PMwith warnings already issued in Mississippi, Alabama and Georgia. Tennessee and Carolinas are next line.
  • What to do: If you suspect sky conditions are changing suddenly, seek shelter immediately. Don't wait for an alert, watch or warning to make it official that threatening weather is approaching your area.
ZONES AFFECTED You can visit our local team reports in affected zones such as Central Virginia, the Carolinas, East Tennessee, Metro Atlanta, Central Mississippi and Southern Georgia. 

9:40 AM EST 2/24/12 The risk of severe weather in the Mid-Atlantic and Southeast this afternoon is increasing, specifically the Virginia Tidewater region (Facebook). Our latest Facebook reports are also reposted in our Severe Weather/Winter Storm section on this site.

Photo from a Maryland reader of a storm front in 2011
7:10 AM EST 2/24/12 Our Southeast and Mid-Atlantic Teams are tracking the movement of a strong cold front set to cross the Eastern U.S. today. The Low pressure associated with this system is also spawning Winter Storm Warnings for northern New York and northern New England, set to produce 6-10 inches of snow in those areas.
  • Our Central Maryland Team reports that for the Baltimore-Washington area,  "temperatures will be climbing near 70° and winds will begin howling at 20 mph with some higher gusts. After the cold front passes, winds will strengthen to around 30 mph sustained with gusts to 50 mph."
  • Our Metro Atlanta Team (on Facebook) reports that for the North Georgia area, "Once the line of thunderstorms rolls through, the winds will pick up (gusts to 35mph) and the temperatures will stay steady near 60 degrees (58-60). Windy conditions will continue Friday night with partly cloudy skies and temperatures near freezing (31-33)."
Tell us in the comments how weather is on the move in your area. Local and regional Facebook pages where you can track our reports include our Southeast page, and our Severe Weather pages for the SoutheastMid-Atlantic and Ohio Valley (Facebook links).    

Thursday, February 23, 2012

A tricky Thursday

Storm Prediction Center outlook for today shows risk of strong storms
rom the Ohio & Tennessee Valleys to the Southeast and the East Coast.  

5:25 AM CST 2/22/12 (Forecaster Kelton Halbert) The Storm Prediction Center has centered a vast majority of the Southeast within a severe weather risk for Thursday evening. 
  • Event type: This appears to be a squall line event beginning in Tennessee, working its way through Mississippi/Alabama late evening into the overnight hours. 
  • Main risks: The main risk appears for damaging straight line winds and hail, although a few isolated tornadoes are not out of the question. 
  • Probabilities: The chances go up for tornado potential with any storms that initiate ahead of the main line. However, low level shear is questionable in some areas. More about the tornado potential will not be known until Thursday morning.

ANALYSIS Uncertainty and variability exists in the forecast; the track of the surface low and cloud cover are all issues that could limit severe, specifically tornado, potential. Weather models are having difficulty resolving issues with an upper level Low off of the west coast of Mexico. Regardless, a damaging wind event appears possible tomorrow evening in Tennessee progressing into the late evening hours.

A detailed blog post on additional scientific analysis has been compiled in our Affiliate page, Tempest Chasing, operated by Forecaster Kelton.  Another update will be posted following a team chat and atmospheric dynamics for this event become more clear

Wednesday, February 22, 2012

1 comment:
Bring on Spring?

Submitted by a reader to our Central Maryland Team
6:00 AM EST 2/22/12 After a stormy winter of severe weather thus far in the South, at least we have calm conditions for much of the U.S. on this Ash Wednesday. Readers and flowers alike in the North are befuddled as to what climate patterns behold heading into March. As recent snowcover retreats North, pre-Spring temperatures in the 60s and 70s return for much of the eastern U.S.  

Severe storms along the coast? Our Severe Weather Team has been closely watching outlooks from the Storm Prediction Center suggesting an increasing risk of dangerous thunderstorm activity Thursday into Friday along the southeast coast. We encourage you to check back each day this week for additional details in the event this potential becomes more serious.    

Although Hope Springs Eternal, the appearances of winter in an early demise can be deceiving, in a La Nina-influenced pattern. A fast moving cold front sweeping across the country on Thursday and to the east coast by Friday will shock many of us back into a winter reality. Already, the next system in the Pacific Northwest is producing High Wind Warnings in Washington State as observed noted by Forecaster Mark in a post on his Tri-Cities Weather page.

Long range signals So we ask, how do you deal with this "weather whip-lash" of warm then cold and wintry conditions followed by warmth again? Perhaps some advance information about March would help you cope, from our Long Range Team:
  • Late February to early MarchWe see ridging over the Southern Plains, and troughing over the Pacific Northwest and Northeast coasts. This would support a drier pattern in Texas and the south into next week as shown above.
  • Early to mid-March: Long range climate teleconnections and the 6-10 day NOAA outlook suggest a deeper western U.S. trough, which should lead to a ridge in the central and eastern U.S. This arrangement would produce a series of storms ejecting toward the east, mixed in between periods of warmth. 
Chances for snow? As we like to say on the team, those in the Mid-Atlantic may be looking for snow in all the wrong places. If you want the "best chance" for powder, you have to visit the "traditional places" nowadays, such as Dallas, Atlanta or Richmond. You want a blizzard in Baltimore? Sorry, that's so 2010. ;-)

(Forecaster Foot and Long Range Coordinator Nic Roberson)   

Tuesday, February 21, 2012

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Upside down weather

7:25 AM 2/21/12 A special report by Advisor / Meteorologist H. Michael Mogil who offers an overview of the forecasting process in the Mid-Atlantic snowstorm this past weekend. 

More than 8 inches of heavy wet snow fell in central Virginia,  leaving thousands without power in the state over the weekend. For those with access to Facebook while reading this, take a look at the local reports provided by our Central Virginia Team as evidence of how the storm played out. Now, if you are wondering about the process of snow forecasting, Mr. Mogil breaks it down in a understandable way that covers why some storms work out, and others do not.
Even more interesting, is that his report was written on February 18, before the storm even got underway in the Mid-Atlantic. His forecasts in the article were, as we say in our team rather "spot-on."  Visit the article and compare for yourself. We offer an excerpt to get you started...
"Close call for Mid-Atlantic snowstorm"                                        2/18/12 article by Mike Mogil

"It has been a mostly snowless winter so far across much of the mid-Atlantic.  In recent days, a developing Gulf Coast low-pressure system gave some (especially students) the hope that their wait for snow would be ending.  That no longer appears to be the case.
For readers who don’t fully understand how snow forecasting is done, let me offer some insights. I caution, however, that this is the proverbial 'tip of the iceberg'  summary.  The forecasting process is much more complicated.
Let’s consider snow forecasting to be a recipe.  Much like kitchen recipes, one needs to have a bunch of ingredients in place in order to make the dish.  In the case of snow forecasting:
  • There needs to be enough cold air through a sufficient depth of the lower atmosphere;
  • An ample moisture supply and something to allow for the moist air to rise (creating clouds and precipitation).  
  • Elevation factors can play a role, as well.  It is typically colder in the mountains than at lower altitudes.  Then the key forecast factor turns into a realtor-based phrase, 'location-location-location.' " 
Visit the article to see what Mr. Mogil actually forecasted, and compare to what actually happened. 

About the author (from his profile) H. Michael "Mike" Mogil, a Meteorologist/Advisor to the U.S. Foot's Forecast Team. is a nationally recognized, educationally-focused, meteorologist with expertise in weather forecasting, science writing, teacher training and forensic applications. He is also able to see how weather connects to other aspects of our lives (e.g., the 2010 oil spill in the Gulf, health and safety, social sciences, geography and math). He has also authored and/or contributed to numerous books on extreme weather, general weather and weather experiments. Mike fostered publication of a set of cloud stamps by the U.S. Postal Service (2004). Mike speaks often at national weather, science and education conferences and writes frequently for the national Weatherwise magazine. 

Monday, February 20, 2012

Where do we go from here?

7:50 AM EST 2/20/12 In the wake of our departing weekend storm, much of the country is welcoming a much calmer Washington's Birthday than in previous years. In 2011, the same regions that were affected by this storm were under threat of a major ice event which snarled plans for many returning home from their mid-winter vacations. 

Looking to next weekend While still early in model projections, the next notable event to impact the country may be a swiftly moving Arctic front trailing behind a relatively strong Low pressure system progged to move northeast from the Great Lakes. 
  • Cold and more cold: Were this outcome to verify, near-freezing air would surge straight the Gulf coast, making for a very cold weekend for much of the eastern U.S. on Saturday and Sunday.  
  • Just one view: The image shown above is for 1:00 AM EST Saturday morning 2/25 as of the 1 AM model runs from today, and the 5,000-foot level map was selected for simplicity. As with every medium range forecast outside 5 days, it is not a specific call for one outcome, but an overview of what is on the horizon given the current pattern.
Thanks for the collaboration! Our entire team would like to express thanks to  our many readers across the U.S. for your loyalty and involvement with us in the recent storm. The forecasters were very encouraged to read of so many  supportive  comments, or to see readers posting pictures of the event from their area in their forecast zones. We appreciate you sharing your weather with us!

(Forecasters Foot, Isaacs; Advisors Berk, Palmer, Lear, Winstead and Krichinsky) 

Sunday, February 19, 2012

"Do you see what I see?"

PSU E-WALL LOOPS (Left) Water Vapor | (Right) Infrared Radar

7:35 PM EST 2/19/12 
The question that our Winter Stormcast Team has been wondering for our readers is: "Do you see what I see?" While heavy snow has been reported in Kentucky, North Carolina, western and central Virginia, readers in the Mid-Atlantic are nervously (or excitedly) watching as the low develops off the South Carolina coast. The precipitation shield continues to march ever northward, making us all wonder if this storm has a few more tricks up the sleeve. What are you seeing in your area? Tell us in the comments.

We offer these intriguing observations from our local teams:
  • Heavy snowfall rates of 2 inches per hour have been reported to the Blacksburg VA National Weather Service. The Sterling NWS has just raised snow totals in Central Virginia. Details on our page there
  • Lightning being reported in southwest Virginia, with one observer noting there was also "distant lightning" in other locations.
  • An upper air sounding at 1:00 PM today in the vicinity of the lightning, showed steep lapse rates of 7.1 c/km. This is indicative of strong upward motion, leading to higher snowfall rates and possible thundersnow. 
Screen capture as of 4:35 PM
  • Snow in the south is observed near Charlotte, North Carolina where you can see pictures posted by our team in that region.
  • Sleet was reported in by readers in Ocean City, MD and Salisbury, MD with heavy snow in lower southern Maryland in the past 2 hours.
  • Rain and snow are moving north into the Baltimore metro area. For Annapolis, MD we expect light snow to reach the city by 7:00 PM. This area is likely to be where the gradient of snowfall accumulations will set up. Up to with the southern portions of 695 being a northward boundary of accumulation in that area.
We welcome your observations in our Mid-Atlantic Winter Stormcast page on Facebook, or in the comments on this page. Enjoy the snow and stay safe!

Saturday, February 18, 2012

Sunday snowfall in the Mid-Atlantic 

9:00 PM EST 2/18/12 Good evening! Our team still expects a significant winter storm to impact much of the Mid Atlantic during the day Sunday, with the highest impact late Sunday afternoon and evening for most areas. Our snowfall forecasts are preliminary, and may be adjusted as we get closer to this event. For details on the projected amounts and impacts for your area, please visit our Winter Stormcast Page on the Foot's Forecast Website.

                "This storm means business."
-Meteorologist Shundra Stewart, Central Mississippi

1:00 PM EST 2/18/12 
Meteorologist Shundra Stewart of our Foot's Forecast | Central Mississippi zone said this morning what many on our team have been thinking since last night. 

A 3000-mile plume of tropical moisture from the East Pacific is hard to ignore. Forecaster Connor of our Central Maryland team noted that several computer models have begun the interesting shift back north in the eventual storm path Sunday into Monday. 

(Meteorologist Shundra Stewart) Rain, rain and more rain. That's one part of the story for today. We also have tornado watches along the gulf coast states. Louisiana and Mississippi Gulf coast counties are currently under a Tornado Watch until 3:00pm ahead of that warm front. A new Tornado Watch was just issued for southern gulf coast counties of Alabama and western part of the Panhandle of Florida until 5:00pm. A low pressure system on the border of TX and Mexico that's going to push north northeastern bring rain to Texas and Louisiana while a warm front is pushing northern bringing severe weather to parts of Louisiana and Mississippi coast counties. Please visit our Southeast Team Forecast page in Facebook for local and regional updates from our seven-state team.

Please visit the Winter Stormcast Page for the latest analyses on why we believe the current storm in the Southeast is already trending farther north, as evidenced by the radar below among other indicators. 

Need another tidbit? Take a look this fun quote from the Winter Storm Watch statement from the Blacksburg VA National Weather Service. This should give pause to astute readers, meteorologists and scientists out there ... "