Ramblings of a Graduate Student

Tonight is/was the 2nd Annual NWC Benefit Bash.  It was an event I started last year to help raise money and awareness for victims of weather related disasters.  Last year the event raised money for a young girl who lost both her parents in the 10 February 2009 Lone Grove, OK EF-4 tornado.  This year the event raised money for the Central Oklahoma Chapter of the American Red Cross to help restore their depleted funds after the Christmas Eve Blizzard in 2009.

In keeping with the theme, the image below is a water vapor satellite image from approximately noon central standard time on Christmas Eve.  It shows a very strong upper-low poised just south of Oklahoma.  As Oklahomans quickly learned, the track the upper-low took is very favorable for heavy snow in the Oklahoma City metro.  Ultimate, when all was said and done, Oklahoma City broke the all-time record for most snow in 24 hours and the most snow from a single storm with an official total of 13.5″ of snow at Will Rogers World Airport.

With this said, another snow storm is poised to affect the southern plains late tomorrow into early Tuesday.  I’ll have more on this tomorrow.

Today weatherpersons all across the United States are celebrating National Weatherperson’s Day.  I know a lot of people consider Groundhog Day (2 February) to be National Weatherperson’s Day because, after all, what screams weatherperson more than a furry rodent looking for its shadow?  However, they would be wrong.  It is celebrated on 5 February because today is the anniversary of American John Jeffries’ birth, who began recording daily weather observations in Boston, MA in 1774.  Jeffries is considered to be one of the first weather observers in what became the United States.  This day celebrates meteorologists’ continuous efforts to produce the best forecasts and warnings.

With this said, there is a lot of high-impact weather to observe across the United States today.  The strong shortwave trough over eastern Colorado last night has continued to dive east-southeast into central Kansas and is aiding in the development of widespread snow across eastern Kansas and much of Missouri.  Also, the conglomeration of weak shortwave troughs over the Gulf of Mexico last night continue to track off to the northeast aiding the development of extremely widespread precipitation across much of the eastern United States.

The areas shaded in blue are places where a computer model believes the precipitation is falling as snow; orange is a mixture of rain, freezing rain, sleet, or snow; and green is rain (or thunderstorms).  As you can see, snow is evident from the far western edge of the map (in reality it extends all the way into Missouri) all the way to the east coast.  All of this precipitation will slowly move east over the next 24-36 hours yielding a near historic snowfall for the Washington D.C. area.  In fact, Washington D.C. is under a Blizzard Warning!  16-22″ of snow is expected to fall overnight!

Below is the text of a Special Weather Statement issued by the National Weather Service Forecast Office in Sterling, VA (which covered the Washington D.C. metro).  Notice the strong wording and the 20-30″ totals that are expected.  Earlier today I saw some model guidance that predicted almost 40″ of snow!  Sheesh!

000
WWUS81 KLWX 051734
SPSLWX

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1234 PM EST FRI FEB 5 2010

DCZ001-MDZ004>007-009>011-013-014-016>018-VAZ042-050>057-501-502-
060145-
DISTRICT OF COLUMBIA-FREDERICK MD-CARROLL-NORTHERN BALTIMORE-
HARFORD-MONTGOMERY-HOWARD-SOUTHERN BALTIMORE-PRINCE GEORGES-
ANNE ARUNDEL-CHARLES-ST. MARYS-CALVERT-LOUDOUN-ORANGE-CULPEPER-
PRINCE WILLIAM/MANASSAS/MANASSAS PARK-FAIRFAX-
ARLINGTON/FALLS CHURCH/ALEXANDRIA-STAFFORD-SPOTSYLVANIA-
KING GEORGE-NORTHERN FAUQUIER-SOUTHERN FAUQUIER-
INCLUDING THE CITIES OF...WASHINGTON...FREDERICK...WESTMINSTER...
GAITHERSBURG...COLUMBIA...BALTIMORE...ANNAPOLIS...WALDORF...
ST MARYS CITY...LEESBURG...CULPEPER...MANASSAS...MANASSAS PARK...
FAIRFAX...ALEXANDRIA...FALLS CHURCH...FREDERICKSBURG...WARRENTON
1234 PM EST FRI FEB 5 2010

...RECORD SNOWFALL FORECAST IN THE BALTIMORE-WASHINGTON DC REGION...

...EXTREMELY DANGEROUS WINTER WEATHER CONDITIONS DEVELOPING TONIGHT...

GUSTY NORTHEAST WINDS 20 TO 30 MPH WITH VISIBILITIES FREQUENTLY
FALLING BELOW ONE-QUARTER MILE DUE TO HEAVY SNOW WILL DEVELOP
TONIGHT TO PRODUCE NEAR-BLIZZARD AND EXTREMELY HAZARDOUS WINTER WEATHER
CONDITIONS TONIGHT THROUGH SATURDAY MORNING.  TRAVEL IS HIGHLY
DISCOURAGED TONIGHT AND WILL BE VERY DANGEROUS.

LOOKING BACK AT THE BIGGEST STORM OF RECORD FOR WASHINGTON DC... THE
JANUARY 1922 KNICKERBOCKER STORM...28.0 INCHES OF SNOW WAS
PRODUCED FROM 3.02 INCHES OF LIQUID WATER.  CURRENT FORECASTS FOR
THIS EVENT HAVE TOTAL LIQUID FALLING FROM THIS STORM APPROACHING 3
INCHES...WHICH ACCORDINGLY WOULD CREATE A SNOWFALL THAT WILL RIVAL
THE KNICKERBOCKER STORM TOTAL.  GENERALLY ACROSS THE REGION...20 TO
30 INCHES OF SNOW WILL FALL BY SATURDAY EVENING.

BALTIMORES RECORD OF 26.8 INCHES FROM THE PRESIDENTS DAY FEBRUARY 2003
STORM WILL ALSO BE THREATENED.

A FEW PRECAUTIONARY AND PREPAREDNESS ITEMS TO NOTE:

1.  FOLLOW MANUFACTURERS INSTRUCTIONS WHEN OPERATING A GENERATOR OR
AXILLARY HEATER.  ENSURE PORTABLE GENERATORS ARE ADEQUATELY VENTILATED.

2.  TRAVEL CONDITIONS TONIGHT ACROSS THE REGION WILL BE EXTREMELY
DANGEROUS AND LIFE THREATENING.  HELP YOUR LOCAL AND STATE
GOVERNMENT FIRST RESPONDERS AND TRANSPORTATION AGENCIES BY STAYING
OFF ROADS LATER THIS EVENING AND TONIGHT.

3.  FOLLOW LOCAL AND STATE GOVERNMENT EMERGENCY DECLARATION ORDERS.
IF YOU ABSOLUTELY NEED TO TRAVEL IN AN EMERGENCY...DO NOT TRAVEL
ALONE.  LET SOMEONE KNOW YOUR TIMETABLE AND YOUR PRIMARY AND
ALTERNATE ROUTES.  CARRY WITH YOU A WINTER STORM SURVIVAL KIT WHICH
INCLUDES A MOBILE PHONE...BLANKETS...FLASHLIGHT WITH EXTRA
BATTERIES...HIGH CALORIE NON-PERISHABLE FOOD AND WATER...AND A
SHOVEL.

4.  IF YOU GET STRANDED IN YOUR VEHICLE...DO NOT LEAVE YOUR CAR TO
TRY TO WALK FOR ASSISTANCE...YOU CAN QUICKLY BECOME DISORIENTED IN
WIND DRIVEN SNOW AND COLD.  THIS STORM WILL SUBSIDE SATURDAY
AFTERNOON...SO WAIT IN YOUR CAR FOR EMERGENCY HELP TO ARRIVE.
PERIODICALLY RUN YOUR ENGINE FOR ABOUT 10 MINUTES EACH HOUR FOR
HEAT. ENSURE YOUR EXHAUST PIPE IS CLEARED OF SNOW AND ICE.  CRACK
YOUR WINDOWS TO AVOID CARBON MONOXIDE POISONING. TIE A COLORED CLOTH
TO YOUR CARS ANTENNA TO BE VISIBLE TO RESCUERS. FROM
TIME-TO-TIME...MOVE YOUR ARMS...LEGS...FINGERS...AND TOES TO KEEP
BLOOD CIRCULATING.

5.  AVOID OVEREXERTION WHEN SHOVELING SNOW.  BREAK THE SHOVELING
DOWN INTO SMALLER JOBS AND TAKE FREQUENT BREAKS.

6.  IN CASE OF POWER SUPPLY DISRUPTIONS...HAVE AVAILABLE FLASH
LIGHTS WITH EXTRA BATTERIES...EXTRA FOOD AND WATER...EXTRA MEDICINES.

7.  ENSURE ANY PETS AND FARM ANIMALS HAVE PLENTY OF WATER...FOOD...
AND SHELTER.

FINALLY...THE KEY TO GETTING THROUGH THIS AND OTHER PERIODS OF
HAZARDOUS WINTER WEATHER IS WITH ADVANCE PLANNING AND BEING AWARE OF
CURRENT CONDITIONS.  THIS STORM WILL BE WINDING DOWN EARLY SATURDAY
EVENING...SO DO YOUR PART AND LET YOUR LOCAL AND STATE GOVERNMENTS
RESTORE ROADWAYS TO NORMAL CONDITIONS BY STAYING AT HOME.

$$

LEE/CS

As I alluded to in last night’s post, the mid-Atlantic states are preparing for what could be their second major snow storm this winter.  Back in mid-December, portions of the mid-Atlantic received upwards of 2 feet of snow from storm very similar to the one forecast to affect the area tomorrow into early Sunday.  Tonight I thought I’d take a few minutes to jot down a few remarks about the ingredients coming together in the mid-troposphere to enable such a major winter storm.  We’ll begin with my favorite piece of observational data – the water vapor satellite image.  I’ve previously mentioned why water vapor imagery is so valuable to meteorologists, so I’ll spare you the repeat of information.  Suffice it to say, if I could only look at one chart a day, this would be the one I would choose.

I’ve identified several shortwave troughs (upper-low) / vorticity* maximums in the above water vapor image via a yellow ‘X’.  [As an aside, meteorologists are often interested in minimums (min) and maximums (max) in vorticity.  To label these phenomena, meteorologists use a 'N' for the miNs and a 'X' for the maXs.]  Looking at the above image, I’ve used two big ‘X’s and two small ‘x’s.  The size of the ‘X’ is to help identify the stronger maximums in vorticity (shortwave troughs / upper-lows).  We’ll ignore the strong shortwave trough off the west coast as it will have little, if any impact on the east coast snow storm.

There is a minor shortwave trough over central Texas that is heading northeast toward eastern Oklahoma.  This shortwave trough will most likely be absorbed into the larger trough that is moving east-southeast out of eastern Colorado.  There is also a minor shortwave trough over the central Gulf of Mexico that is lifting northeast toward Georgia.  It is this shortwave trough that will begin to affect the east coast late tonight into Friday with the first bout of precipitation.  I’ve also circled an area of the western Gulf of Mexico in yellow.  I believe that there is another minor shortwave trough somewhere in the circled area, but it is not discernible from a single satellite image.

Over the next 48 hours, the shortwave tough(s) over the Gulf of Mexico will move toward Georgia and then off the mid-Atlantic coast. This trough will help to draw warm, moist air northward from the Gulf of Mexico into the mid-Atlantic region.  This warm, moist air will encounter very cold air at the surface causing the warm, moist air to be lifted into the atmosphere.  Widespread precipitation – in the form of snow in areas away from the coast – will begin to develop and spread northward overnight into tomorrow as a result of this.  At the same time, the stronger trough over eastern Colorado will continue to track east-southeast toward eastern Tennessee.  This stronger tough will continue to strengthen over the next 48 hours and help to draw even more warm, moist air northward into the storm.  The interaction of the two troughs will help to generate a very strong low-pressure system at the surface that will further enhance the precipitation in the vicinity of the Delmarva Peninsula (general area of Washington D.C.).  Just north and west of the eventual track of the surface low will receive a prolonged period of very heavy snow that will allow for accumulation of up to 24-30″ in some areas.  Furthermore, as the two upper-level lows (shortwave troughs) continue to interact with each other, and the surface low moves over the warm waters of the gulf stream current, the low should continue to strengthen.  As the low does this, very strong northeast winds will develop along the coast (hence where we get the name ‘Noreaster’) and blizzard like conditions will be possible.  In fact, portions of New Jersey already have Blizzard Warnings in effect for this potential!

People in the Washington D.C. area are hopefully prepared for a winter storm that could potentially shut down the city through the weekend.  Some good-natured citizen has created a “snowpocalypse” website for Washington D. C. residents to gain the latest information.  So, as a public service for those who might be affected by the east coast winter storm, please visit http://snowpocalypsedc.com/for the latest information.

*Vorticity is a mathematical quantity used to quantify the potential for an air molecule to exhibit ’spin’.  Over simplifying this complex phenomenon, where ’spin’ is being blow toward tends to experience rising motion and wherever the ’spin’ is blowing from tends to experience sinking motion.