Transcript 2009 Winter Outlook - Association of County Commissions of

2014-15 Winter
Weather Outlook
North Alabama Area
Actual
Monday Night
Low (°F)
Record
Monday Night
Low (°F)
Forecast
Tuesday 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)
21° *
22° (2008)
33°
36° (2000)
Scottsboro
20°
18° (1959)
33°
36° (1959)
Fayetteville, TN
18°
15° (1959)
32°
32° (1959)
Location
Decatur Airport
* New Record
In An Average Year...
Averages based on 1981-2010 data
NOV DEC
JAN
FEB
MAR
63.7°
41.8°
4.94”
0
51.2°
31.8°
4.89”
1.1”
55.9°
35.5°
4.84”
0.5”
64.9°
42.2°
5.21”
0.5”
53.5°
34.4°
5.77”
0.3”
Average: 2.4” Snow
Through November 17:
* Max Temp: 59.6
* Min Temp: 36.2
Calendar Day Record:
15.7” (12/31/63)
Season Record:
24.1” (’63-’64)
Recent Winters in Huntsville
Coldest Temperatures
Snowfall
Season
Temp (F)
Season
Snowfall
‘03-04
15
‘03-04
Trace
‘04-05
14
‘04-05
Trace
‘05-06
16
‘05-06
0.6”
‘06-07
14
‘06-07
1.0”
‘07-08
14
‘07-08
0.7”
’08-09
9
’08-09
0.7”
’09-10
13
’09-10
3.2”
’10-11
8
’10-11
14.3”
‘11-12
19
‘11-12
Trace
’12-13
21
’12-13
0.7”
’13-14
4 **
’13-14
5.2”
** Coldest since Feb. 1996
Seasonal Average: 2.4”
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
NWS Huntsville’s Winter Weather Products
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
** Note: Criteria for each product is a guideline and public
safety/IMPACTS are taken into consideration
Stay Informed / Be Prepared
NWSChat
Web / Internet
Phone
Social Media
800MHz Radio
Mobile
iNWS
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
Upper level Low
Low pressure just to south –
shallow cold air scenario
Northern Plains “Clipper”
system
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
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.
Positive NAO
Winter 2011-2012
Strong Low
Strong High
Seasonal Outlooks
The 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.
Negative NAO
Winter 2010-2011
Weak Low
“blocking”
Weak High
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 AO & 7-14 day Forecast
Observed NAO & 7-14 day Forecast
For more Climate/Outlook
information…
• Visit our web page:
Click on
Temperatures/Precipitation
for each specific Region
http://www.srh.noaa.gov/hun/?n=elnino_winter_study
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!!