NOAA’s National Weather Service

NOAA’s National Weather Service

2012-2013 Winter Season Outlook2012 NCEMA Fall Conference

Nick Petro, WCM NWS Raleigh, NCTony Sturey, WCM NWS Greer, SC

Phil Hysell, WCM NWS Blacksburg, VA


Presentation Outline

• Introduction (Tony)

• Climatology and geographic influences (Nick)

• Winter season products and services (Phil)

• Outlook for this upcoming winter season (Tony)






* *

Winter Storm Prediction:Challenges

Nick Tony Phil

Climate Prediction Centerhttp://www.cpc.ncep.noaa.gov






Geographic InfluencesDue to NC’s proximity to the Appalachian Mountains, Atlantic Ocean, Gulf Stream, and Gulf of Mexico, various weather patterns can result in winter weather across the state.

Geographical Features

Gulf Stream

Highest Mtns in

Eastern US

Labrador Current

H

The Primary Challenge:Depth of Cold Air

3 typical scenarios

One Organized Low

Offshore Track

Inland Track

Complex PatternMultiple Lows Separated by CADJan 7, 1996

Corridors of Predominant P-Type

Winter Weather Climatology

National Weather Service

• Winter weather season typically runs between December and March.

• Predominate snow events are most common over the northwest, with least occurrences along the coast.

• Freezing rain is most often predominate over the Northern Piedmont Damming Region (due to CAD).

• Sleet is rarely the predominate winter storm precipitation type (it is typically found with transition zones of precipitation).

North Carolina’s Annual Average Snowfall


North Carolina’s Number of Days with Snow and Sleet Accumulation


North Carolina’s Number of Events per Year with Sleet and Freezing Rain


A Typical Strong Winter Storm with Cold Air Damming







Winter Weather Resources

Snowfall Criteria in NC



Ice Storm Warning Blizzard Warning• In lieu of a Winter Storm

Warning, an Ice Storm Warning is issued if the precipitation type will be all ice

• At least ¼ inch of ice in 12 hours

• Less than ¼ inch of ice handled with a Freezing Rain Advisory

• No such thing as an “Ice Storm Watch”

• Sustained or frequent gusts >/=35 mph AND considerable blowing/drifting of snow reducing visibilities frequently < ¼ mile.

• Blizzard Watches can also be issued.

www.weather.gov

weather.gov

weather.gov

weather.gov

weather.gov/blacksburg

weather.govHow can I determine the forecaster’s confidence?

weather.govHow can I determine the forecaster’s confidence?

Jan 16, 2008 Forecast Discussion

Winter Storm Example3-7 Days in Advance of The Event

Winter Storm Example3-7 Days in Advance of The Event

www.hpc.ncep.noaa.gov





Winter Storm ExampleWinter Storm Arrives

http://www.srh.noaa.gov/ridge2/ridgenew2/

Winter Storm ExampleSnowfall/Ice Reports

Winter Storm Examplehttp://srh.noaa.gov/ridge2/snow/

NWSChathttps://nwschat.weather.gov

• Provides EM, media, SKYWARN and other partners to exchange information with NWS forecasters anytime.

• Already integrated within NWS operations.• Can run on any PC as well mobile devices

such as a Blackberry or Droid.

Links provided to all products seconds within issuance including warnings

Weather on the Go!

• NC-First mobile app

• http://mobile.weather.gov/

• https://inws.wrh.noaa.gov

http://mobile.weather.gov/

https://inws.wrh.noaa.gov/

https://inws.wrh.noaa.gov

NOAA Weather RadioWhy Not Have A Tornado Siren In

Your Home, Work, or Car?

• Receive weather information

24 hours a day.

• Radio will sound a tone to alert you when a watch/warning has been issued.

• Countless times, lives have been saved by NOAA All-Hazards Weather Radio


Thank You!






Outlook for 2012-13 WinterThe National Weather Service uses the latest technology and does exhaustive research to

determine long-range forecast conditions

What’s a few inches of snow to you?

Changes in the Wintertime Atmospheric Flow Related to El Nino

• More west-to-east flow of jet stream winds than normal across the United States

• An eastward extension of the jet stream winds from the International Date Line to the southwest United States

• A southward shift of the storm track from the northern to the southern part of the United States

• This shift results in an exceptionally stormy winter and increased precipitation across California and the southern U.S. and less stormy conditions across the northern part of the country.

The Upshot• Overall a greater number of opportunities for low pressure

systems tracking nearby (Southeast Conus) compared to last winter.

• Will we cash in? The amount of precipitation we receive will be modulated by whether the southern low pressure systems move across the deep south and out to sea, or make a turn up the East Coast or through the Carolinas!

• If we cash in, what will be the outcome? Temperatures are the wildcard in this pattern! Usually cold air is “locked north” because of the jet stream configuration. Therefore our analysis would be for a greater potential for messy mixtures, based on the long range temperature probabilities. However weather history has shown us that the entire spectrum of precipitation types are in play during El Nino Episodes: 1969-70; 1976-77; 2004-2005.

• Note, it is not uncommon to jump temporarily out of these types of regimes for a week or two, and then revert back into the overall El Nino Episode.

Questions? Contact information:

• Nick Petro, WCM Raleigh• [email protected]

• Phil Hysell, WCM Blacksburg• [email protected]

• Tony Sturey, WCM Greenville/Spartanburg• [email protected]

Date post:	23-Feb-2016
Category:	Documents
Upload:	vondra
View:	35 times
Download:	0 times

NOAA’s National Weather Service

Documents