2014-15 Winter Weather Outlook

North Alabama Area

Record November COLD!!

Location

ActualMonday Night

Low (°F)

Record Monday Night

Low (°F)

ForecastTuesday High

(°F)

Record (Low Max)

Tuesday High (°F)

Huntsville Airport

22° 18° (1959) 32° 36° (2000)

Muscle Shoals Airport

21° 18° (1959&1914)

33° 36° (1903)

Decatur Airport 21° * 22° (2008) 33° 36° (2000)

Scottsboro 20° 18° (1959) 33° 36° (1959)

Fayetteville, TN 18° 15° (1959) 32° 32° (1959)* New Record

In An Average Year...

NOV DEC JAN FEBMA

R63.7

°53.5

°51.2

°55.9

°64.9

°

41.8°

34.4°

31.8°

35.5°

42.2°

4.94”

5.77”

4.89”

4.84”

5.21”

0 0.3” 1.1” 0.5” 0.5”Average: 2.4”

SnowSeason Record:

24.1” (’63-’64)

Calendar Day Record:15.7” (12/31/63)

Averages based on 1981-2010 data

Through November 17:* Max Temp: 59.6* Min Temp: 36.2

Recent Winters in Huntsville

Season Temp (F)

‘03-04 15

‘04-05 14

‘05-06 16

‘06-07 14

‘07-08 14

’08-09 9

’09-10 13

’10-11 8

‘11-12 19

’12-13 21

’13-14 4 **

Season

Snowfall

‘03-04 Trace

‘04-05 Trace

‘05-06 0.6”

‘06-07 1.0”

‘07-08 0.7”

’08-09 0.7”

’09-10 3.2”

’10-11 14.3”

‘11-12 Trace

’12-13 0.7”

’13-14 5.2”

Coldest Temperatures

Snowfall

Seasonal Average: 2.4”

** Coldest since Feb. 1996

NWS Winter Weather Products

• Outlooks– Hazardous Weather Outlook– Special Weather Statement

• Watch– Winter Storm Watch– Ice Storm Watch

• Warning / Advisory– Winter Storm Warning– Ice Storm Warning– Winter Weather Advisory– Freezing Rain Advisory

** Blizzard Warnings can be issued when strong winds accompany heavy snow

Product Criteria

Winter Storm Watch At least a 50/50 chance that warning criteria (>2 inches of sleet/snow and /or ice accumulations of 1/4 of an inch or greater) will be met in the next 12 to 24 hours.

Winter Weather Advisory 1" to 2" of snow and/or sleet in less than 12 hours **

Freezing Rain Advisory Ice Accumulations up to 1/4”

Wind Chill Advisory Wind chill readings between -10°F and 0°F

Winter Storm Warning Greater than 2" of snow and/or sleet in 12 hours or > than 4" of snow in 24 hours

Ice Storm Warning Ice accumulations of 1/4" or greater

Wind Chill Warning Wind chill readings at or below -10°F

Blizzard Warning Greater than 2" of snow and/or sleet in 12 hours or greater than 4" of snow in 24 hours AND sustained winds of 35 MPH or greater AND considering blowing and drifting snow reducing visibilities to 1/4 mile or less for 3 or more hours

NWS Huntsville’s Winter Weather Products

** Note: Criteria for each product is a guideline and public safety/IMPACTS are taken into consideration

Stay Informed / Be PreparedNWSChat

iNWS800MHz RadioSocial Media

PhoneWeb / Internet

Mobile

NWS Huntsville 24/7 Contact Info

• Phone:– 256.890.8503 / 8507 / 8508

• 800 MHz Radio:– 1*77*183 (base station)– 283 (Dave)

• Social Media– NWS Huntsville (FB) / @NWSHuntsville

(Twitter)• NWSChat – “hunchat”• Web: www.weather.gov/huntsville

EM Briefing Page (Internal)

Winter “tab” will also show• Wind chill forecast • Snow/Ice accums

http://www.srh.noaa.gov/hun/?n=embrief_winter

Staying Informed / Planning

NWS Huntsville webpage – http://www.weather.gov/huntsville

Winter Precipitation Types

TN Valley Winter Weather Scenarios

Coastal Low Track

Low pressure just to south – shallow cold air scenario

Northern Plains “Clipper” system

Upper level Low

Seasonal Outlooks

• Things to keep in mind…– They are probabilistic outlooks– “Equal Chances” does not mean “Near

Normal”• 33% of near normal• 33% of above normal• 33% of below normal

• Other climate patterns/variables in play– El Nino/La Nina– North Atlantic Oscillation (NAO)– Arctic Oscillation (AO)

Taken from NOAA’s Climate Prediction Center

Taken from NOAA’s Climate Prediction Center

Latest on El Niño • El Niño WATCH

– Issued when conditions are favorable for the development of El Niño conditions within the next six months.• There is a 58% chance

of El Niño during the Northern Hemisphere winter, which is favored to last into the Northern Hemisphere spring 2015.

Typical El Nino Climate Pattern

North Atlantic Oscillation

• Among the most important modes of seasonal variability in the Northern Hemisphere

• Represented by pressure changes in the North Atlantic

• Positive/Negative phase

• State of the science does not allow for reasonable predictions of either negative or positive phases of NAO beyond about 2 weeks

LH

NAO – Positive vs. Negative Phase

• The Positive Phase

• Low Pressure system near Iceland and the Azores High Pressure system are both generally strong.

• This creates an upper zonal wind flow pattern and colder air tends to stay up north in Canada and Alaska.

LH

Strong Low

Strong High

Cold AirStays North

Warm Air

Positive NAOWinter 2011-2012

Seasonal OutlooksThe North Atlantic Oscillation (NAO)

• The Negative Phase• The Icelandic Low,

and the Azores High will often weaken considerably.

• This creates a highly amplified pattern where blocking occurs upstream in the Atlantic. This causes cold air to flow southward into the United States.

L

H

Weak Low

Weak High

Cold AirPlunges

South

Warm Air

“blocking”

Negative NAOWinter 2010-2011

Arctic Oscillation (AO)• Drives temperatures during Winter

months• Involves strength of Polar Jet Stream

(Arctic Circle)• Positive / Negative phase (like NAO)

– Positive = strong jet = cold air locked up– Negative = weaker jet = cold air can shift

south

AO / NAO – where are we now?

Observed NAO & 7-14 day Forecast

Observed AO & 7-14 day Forecast

For more Climate/Outlook

information…• Visit our web page:

http://www.srh.noaa.gov/hun/?n=elnino_winter_study

Click on Temperatures/Precipitation for each specific Region

Winter Weather Awareness Many people travel across the country, throughout the winter months. It’s

important to look ahead at the weather forecast and plan accordingly, but it’s also important to equip your vehicle with the proper tools/resources in case winter

weather impacts your area.

Have one of these in your

vehicle!!