Monday, February 25, 2013

Blizzard Threatens Texas All-Time Snowfall Records




8 PM CST February 26 Update: Map updated with final totals.

8 PM CST Update: The Amarillo snow total of 19" is the third heaviest for any storm on record:

4 PM CST Update: Here are some unofficial snowfall reports from the National Weather Service for the Texas panhandle:
Location              Snowfall  Source
7 ENE Amarillo  TX      17      nws office
Fritch          TX      16      trained spotter
Pampa           TX      15      co-op observer
6 SE Booker     TX      14      trained spotter
Fritch          TX      14      trained spotter
White Deer      TX      14      public
Booker          TX      14      emergency mngr
Fritch          TX      13      public
3 S Darrouzett  TX      12.5    trained spotter
Dumas           TX      12      law enforcement
Bushland        TX      12      public
6 SW Amarillo   TX      12      trained spotter 
Original Post:
The ongoing blizzard in the Texas panhandle is threatening to break some all-time Texas snowfall records. These are the current snowfall records at Amarillo, from the National Weather Service:

Max for 24 hours: 20.6 inches on March 25-26, 1934
Max for a single storm: 20.6 inches on March 25-26, 1934
Max for one month: 28.7 inches in February 1903
Max measured snow depth: 17.0 inches on February 26, 1903
Max for a season: 50.9 inches in 1918-19

The NWS at Amarillo reports:
GOING FORECAST STILL ON TRACK. THE NWS OFFICE NOW HAS OVER 13 INCHES
ON THE GROUND WITH 3-4 FOOT DRIFTS AND A MAX GUST TO 58 MPH. THE SE
TX PANHANDLE HAS BEEN SLOW TO FILL IN WITH SNOW AFTER THE
THUNDERSTORMS THAT DROPPED HEAVY RAIN LAST NIGHT AND THESE AREAS
MIGHT END UP WITH AMOUNTS CLOSER TO THE 8 INCH SIDE THAN THE 14 INCH
SIDE OF THEIR RANGE. AT THE END OF THE DAY...THE HEAVIEST TOTALS
WILL ALMOST CERTAINLY BE ALONG A PALO DURO CANYON TO AMARILLO TO
STINNETT TO PERRYTON LINE.

SOME RECORDS SEEM TO BE IN A PRECARIOUS POSITION TODAY. THE FIRST IS
AN ALL-TIME 24 HOUR SNOWFALL RECORD AT AMARILLO OF 20.6 INCHES FROM
MARCH 25-26 1934. WE WILL LIKELY GET VERY CLOSE OR SURPASS THIS
NUMBER BY THIS AFTERNOON.

THE OTHER IS THE ALL-TIME STATE OF TEXAS 24 HOUR SNOWFALL RECORD OF
25 INCHES IN FOLLETT SET MARCH 28 2009. SOMEWHERE IN THE
PERRYTON/STINNETT/BORGER/AMARILLO AREA COULD APPROACH THIS VALUE BY
THIS AFTERNOON.  

Sunday, February 24, 2013

Record Low Mid-Atmospheric Pressure Predicted for Midwest Blizzard


The maximum intensity for the developing Midwest blizzard is nearly 2 days away, but a major forecast model is predicting mid-atmospheric pressures at least as low as any observed during February in the region since systematic upper-air observations began in 1948. Based on data from this morning, the NOAA/NCEP GFS model is predicting super-low pressures by Tuesday morning near the middle of the atmosphere above the storm. The map above shows the predicted height (meters) of the level at which the pressure is 500 mb, or roughly half the value at the surface. The small circle near the Missouri-Arkansas border is labeled 528, or 5280 meters (approximately 3 miles). The values inside the circle would be even lower. According to historical data from NOAA's Earth System Research Laboratory, the 500 mb height has never been as low as 5280 meters in that region since 1948. Here is a list of the top 10 lowest observations in February at latitude 35 N, longitude 90 W:
Date       Meters
1991,2,15, 5287
1964,2,19, 5314
1978,2,21, 5318
1984,2,28, 5323
1965,2,25, 5334
1970,2, 3, 5345
1971,2, 9, 5357
2010,2,15, 5357
1958,2, 2, 5361
1984,2, 5, 5361 

Looked at another way, the composite forecast from an ensemble of GFS forecast runs made from last night's data indicates that the 500 mb height departure from the long-term average will be as much as 5 standard deviations by Monday night (chart to the right, click to enlarge). For a purely randomly distributed event, a negative departure from average of 4.5 standard deviations would occur only 3 times in a million.

Seasonal Outlook

Latest seasonal forecast: Click here.


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