For Remainder of December Frank Nocera Senior Meteorologist - - PowerPoint PPT Presentation

Winter Weather Outlook & Forecast For Remainder of December

Frank Nocera – Senior Meteorologist National Weather Service Taunton, MA December 7st, 2016

Nation ional l Wea eathe ther r Ser ervice vice Ta Taunton, nton, MA

Forecast- Winter 2016-2017 Outlook

• Outlook from NOAA’s Climate Prediction Center:
• https://www.youtube.com/watch?v=KF8YwYUcB_E

(paste youtube link into your browser to watch video)

• El Nino started fading spring-summer 2016
• Fall 2016: Weak La Nina development
• Weak La Nina probable (~55% chance) thru

Winter 2016-17

Long Term: El Nino/La Nina

There are some ocean and atmosphere events that can have substantial influence

• n the US, and more locally New England’s

Weather. One well-known influence is related to the

• ccurrence of prolonged warmer or cooler than

normal temperatures within the Equatorial Pacific Ocean

La Nina- Below normal ocean water temperature El Nino- Above normal ocean water temperature

Map from NOAA Climate.gov

Climate.gov La Nina Advisory

Typical La Nina Weather Pattern Source: http://climate.gov

This graphic represents impacts for a moderate La Nina. Impacts will be different for a strong La Nina (more extreme impacts) & weak La Nina (less extreme impacts)

Resource: Winter Outlook Dec ‘16-Feb ’17 Reflects Forecast of Weak La Nina NOAA Climate Prediction Center- http://www.cpc.ncep.noaa.gov/

Equal Chances = weak atmospheric signal = high uncertainty Thus probabilities less than 33%

How About Winter Predictions From Private Sector Vendors?

Atmospheric & Environmental Research

Near normal temperatures for New England when you average western vs. eastern New England. Equal chances?

WeatherBELL Winter Temp Prediction Very similar to AER (previous slide)

WeatherBELL Winter Snowfall Prediction

• Snowfall at or above normal for RI

Winter Weather Outlook – Final Thoughts

• NOAA Climate Prediction Center (CPC) predicting equal

chances for Temperatures & Precipitation during Dec, Jan & Feb

• Private Sector Vendors predicting temperatures at or colder

than normal Dec, Jan & Feb with precipitation at or above normal

• Seasonal forecasts inherently have high uncertainty given

the time range & this year is no exception with La Nina expected to remain weak, hence not a dominate weather

• feature. Therefore we can not provide any additional value

than to say “equal chances” for temperatures & precipitation for the state of Rhode Island & remainder of New England

CPC 6-10 & 8-14 Day Outlooks

• Much greater forecaster confidence (less

uncertainty) than Winter Weather Outlook given shorter time horizon. Thus greater forecast detail

Resource: Climate Prediction Center 6-10 Day Outlook http://www.wrh.noaa.gov/images/sto/GIS/610temp.jpg

Temperatures at

• r trending colder

than normal into mid December

http://www.wrh.noaa.gov/images/sto/GIS/610prcp.jpg

40% chance

• f above

normal precipitation in New England mid December

http://www.wrh.noaa.gov/images/sto/GIS/814temp.jpg

Temperatures trending colder than normal mid to late December into New England

http://www.wrh.noaa.gov/images/sto/GIS/814prcp.jpg

40% chance of above normal precipitation across New England mid to late December

Final Thoughts 6 to 10 & 8 to 14 Day Outlooks

• Temperatures – at or colder than normal mid to late Dec

(trending colder). Forecast confidence above average

• Precipitation – at or slightly above normal mid to late
• Dec. Forecast confidence above average
• Precipitation Details – two potential precip. events

possible next 2 weeks, 1st event centered on Sun 12/11 to Mon 12/12 with 2nd event centered on Sat 12/17 to Mon 12/19