Winter Weather

National Weather Service Buffalo, NY

Average Seasonal Snowfall

SNOWFALL = BIG IMPACTS

4

• School / government / business closures

• Airport shutdowns/delays

• Traffic accidents with injuries/fatalities

• Money plowing/treating roads

• Lost resources in traffic congestion

• Power outages/damage in strong storms

Communicating Risk Potential

The National Weather Service uses a

“Ready, Set, Go” approach

Substituting the words

“Outlook, Watch, and Warning”

This approach is based on the lead-time of the event and

forecaster confidence.

Hazardous Weather Outlook

• Issued each day between 5am and 6am

• Updated as necessary throughout the day

• Outlines potential weather hazards expected

over the next seven days

• The potential for major storms beyond two days

will be discussed in the HWO

WATCH vs. WARNING

WatchConditions are favorable for severe

weather in or near the watch area.

Watches are issued for winter storms,

ice storms and blizzards.

WarningThe severe weather event is imminent

or occurring in the warned area.

Warnings are issued for winter

storms, ice storms and blizzards.

WINTER WEATHER WATCHES

• Issued when forecaster confidence in the event occurring is at 50% or greater

• Updated at least once every 12 hours or when there is a change in timing, areal extent, or expected conditions.

• Generally issued 24 to 48 hours in advance

• Types:– Winter Storm (Snow, Blowing Snow,

Blizzard, Lake Effect)

– Wind Chill

WINTER WEATHER WARNINGS

• Issued when hazardous winter weather is occurring or is imminent.

• Forecaster confidence is at 80% or greater

• Warnings can be issued based on significant public impact events

• Generally issued 12 to 36 hours in advance

Warnings

• Issued when forecaster confidence reaches 80%

• Types• Blizzard Warning

• Ice Storm Warning

• Lake Effect Snow Warning

• Winter Storm Warning

• Wind Chill Warning

Blizzard Warning

• Wind speeds of 35 mph or greater

AND

• Visibility of ¼ mile or less in blowing snow

AND

• Conditions must persist for at least 3 hours

• Blizzards may or may not be accompanied by falling

snow

– When not accompanied by falling snow, it is referred to as a

Ground Blizzard

• “Severe” blizzard– All of the above except temperatures below 20° F

– Wind chills well below zero

Ice Storm Warning

• Issued when 1/2 inch or more of ice

accumulation is expected

• An Ice Storm Warning means that freezing rain

is expected to be the dominant precipitation type

Winter Storm Warning

• Issued when a combination of snow, sleet, and/or freezing rain are expected to reach warning criteria

• Issued for a general heavy snowfall of:– 7 inches in 12 hours

– 9 inches in 24 hours

Lake Effect Snow Warning

• Issued for a general heavy

snowfall of:– 7 inches in 12 hours

– 9 inches in 24 hours

• Lake effect snow warning implies the localized

nature of the heavy snow – In most cases not everyone in a county will receive warning criteria

snowfall

Wind Chill Warning

• Issued for dangerously cold wind chills– Wind speeds generally 5 mph or greater

• Issued when wind chills are forecast to fall

below -25° F

WINTER WEATHER ADVISORIES

• Issued when winter weather is expected to cause significant inconveniences.

• If caution is not exercised, could lead to life-threatening situations

• Advisories:– Winter Weather

(Snow, Lake Effect Snow, Blowing Snow, Ice or Sleet)

– Wind Chill

17

ALSO NEW THIS WINTER...

18

• Short-fused SNOW SQUALL WARNINGS– Visibilities of ¼ mile or less

– Sub-freezing ambient road temperatures or plunging surface temperatures along and behind arctic front sufficient to produce flash freezes

– Gusty winds and blowing snow

• Beginning December 1st

OUR GOAL

• To provide more information to

– Facilitate improved decision making

– Elicit the proper public response during the most life-threatening weather events

19

Weather Forecasts are Inherently Uncertain

• Chaotic Nature of the Atmosphere

• Deficiencies In Observations

• Uncertainties in Computer Simulations of Atmosphere

Yet the demand for snowfall forecasts has escalated!

20

Accurate Forecasts Desired Days in Advance

But, as Lead Time increases, Certainty decreases

• We need to better communicate the range of possibilities

– Find a balance between Lead Time and Certainty

• NWS constantly striving to provide:

– The most accurate weather forecast

– Relay our degree of uncertainty

21

Our Websites

• www.weather.gov/buf

• http://digital.weather.gov

• http://preview.weather.gov/edd

23

24

Enter a Zip Code

Or City, State

Click Location

on the Map

www.weather.gov/buf

“Point and Click” Forecast

Hourly Forecast Graphs

27

For a text

forecast for a

County

Select

Text Bulletins

then

Zone Forecast

www.weather.gov/buf

http://digital.weather.gov

28

Graphical Forecasts from NWS digital databaseZoom-able to Street Level

Forecasts of:• Temperature

• Wind

• Probability of

Precipitation

• Hazards

• Precipitation

Amounts –

6-hr and total

• Snow amounts –

6-hr and total

http://preview.weather.gov/edd

29http://go.usa.gov/hegF

• Current Observations:

– Radar, Satellite, Hazards, Surface Observations

• Forecasts:

– Forecast Graphics

– Hydrology

Storm Total Forecast

30

Winter Weather Snowfall Rate ThreatBuffalo Forecast Office

http://www.weather.gov/buf/Snowfall_Rate_Threat_Loop

31

329/22/2017

Winter Weather Snowfall Rate ThreatBuffalo Forecast Office

http://www.weather.gov/buf/SnowfallRateThreatTiles

33

Winter Weather Snowfall Rate ThreatBuffalo Forecast Office

http://www.weather.gov/buf/Snowfall_Rate_Threat_Loop

2AM Tuesday 11/18/2014 6AM Tuesday 11/18/2014

www.weather.gov/buf

NWS Weather Information On Your Mobile Phone

35

Take the weather with you on your mobile phone! Wherever you are, you can get the local weather forecast from the National Weather Service with one click on your home screen.

Bookmark mobile.weather.gov to make sure that you have the latest weather news and information on the go.

9/22/2017

Weather Ready Nation Ambassadors

• Partners commit to working with NOAA and other Ambassadors to strengthen national resilience against extreme weather.

• Unifies efforts across government, non-profits, academia, and privateindustry toward making the nation more ready, responsive, and resilient against extreme environmental hazards.

• Ambassadors serve a pivotal role in affecting societal change — helping to build a nation that is ready, responsive, and resilient to the impacts of extreme weather and water events.

5 Fun Facts about Snow

1. All snowflakes have six sides

2. Snow crystals are translucent, not white. All

visible colors are reflected, which together, look

white.

3. Most snowflakes fall at a speed of 2 to 5 feet per

second, roughly the same speed as a person

casually walking through a park

4. Official snowfall and snow depth measurements

include snow, sleet and ice pellets – in the

summer, hail will also be recorded as a trace of

snow if it is on the ground when the observation

is taken.

5. A cubic foot of snow may contain between 1 and

2 million individual snowflakes.

38

Fall begins Friday (9/22) at 4:02 PM

Any Other Questions?