National Weather Service
Steve Gohde
WFO Duluth
Observing Program Leader
Craig Schmidt
WFO Twin Cities
Service Hydrologist
January 6, 2015
Weather and Hydrologic Discussion
 Weather review for mid-late 2014 (precipitation and
temperatures)
 Current Conditions (Snow Pack and Frost)
 Winter Short and Long range outlooks
 Drought outlook
 Hydrologic long range outlook for Island Lake
Reservoir
Island Lake Basin
Weather and Hydrologic Discussion
 Weather review for mid-late 2014 (precipitation and
temperatures)
 Current Conditions (Snow Pack and Frost)
 Winter Short and Long range outlooks
 Drought outlook
 Hydrologic long range outlook for Island Lake
Reservoir
Temperatures Oct. – Dec. 2014 Duluth
•TEMPERATURE
HIGHLIGHTS
• TEMPERATURES
COMPARED TO NORMAL
• SEPT +1.8
• OCT +1.6
• NOV -7.0
• DEC +6.5
• JAN BIT OF BOTH
• SNOW ACCUMULATION
BEGAN NOVEMBER
9THRD. MELTED TO 1”
BY DECEMBER 15TH.
Precipitation at Duluth
VERY NEAR AVERAGE FOR 2014
July – Dec. Precipitation at Duluth
BELOW AVERAGE STARTING IN SEPTEMBER
July – Dec. Precipitation at Brimson
Observed Precipitation
•PRECIPITATION HIGHLIGHTS
• VERY NEAR AVERAGE FOR 2014.
• ANNUAL PRECIPITATION MAY NOT BE A GOOD INDICATION OF CURRENT BASIN CONDITIONS.
• CONSIDER PRECIPITATION SINCE JULY .
• DULUTH 4.04 INCHES BELOW NORMAL
• BRIMSON 3.80 INCHES BELOW NORMAL.
• ABNORMALLY DRY CONDITION ON DROUGHT MONITOR
Water Year Precipitation at Duluth
Water Year Precipitation
Local Observations
 December thaw may have moved a portion of melt
water out of the basin. Rain on snow dramatically
reduced snow depths.
 Latest Snow Depths range from 3 to 6 inches in the
basin. Latest storm fell mostly north of the Laurentian
divide.
 Frost depth is diving quickly with thin snow pack.
Precipitation – Water Year
Percent of Normal
(YTD, since Oct 1)
Pcpn: Much of MN well below normal so far, equating to about 1.5 to 2 inches of water
Weather and Hydrologic Discussion
 Weather review for mid-late 2014 (precipitation and
temperatures)
 Current Conditions (Snowpack)
 Winter Short and Long range outlooks
 Drought outlook
 Hydrologic long range outlook for Island Lake
Reservoir
Dec 5, 2014 – Snow Depth
Depth: 4 to 8 inches over the basin when model was run
Source: NOHRSC
Snow Water Equivalent (SWE) – Dec 5th
SWE: only up to about an inch when model was run
Source: NOHRSC
Snow Water Equivalent (SWE) – Jan 5th
SWE: slight increase since early December
Source: NOHRSC
Dec 31, 2014 – Snow Depth
Depth: 4 to 8 inches over the basin when model was run
Source: NOHRSC
Weather and Hydrologic Discussion
 Weather review for mid-late 2013 (precipitation and
temperatures)
 Current Conditions (Snowpack)
 Winter Short and Long range outlooks
 Drought outlook
 Hydrologic long range outlook for Island Lake
Reservoir
Extended Outlook – 8 to 14 Days
Temperatures: potentially milder
pattern next week
Pcpn: continued
below normal
http://www.cpcpara.ncep.noaa.gov/
30 Day Outlook – January 2015
Temperatures: Rest of Jan a little
below normal
Pcpn: Equal Chances
http://www.cpcpara.ncep.noaa.gov/
Jan, Feb, Mar 2015 Outlook
Temperatures: Equal Chances
Pcpn: Equal chances
Normal Precip (liquid):
• Jan -- 1 to 1.5 inches
• Feb – ~1 inch
• Mar – 1 to 2 inches
http://www.cpcpara.ncep.noaa.gov/
Mar, Apr, May 2015 Outlook
Temperatures: Equal Chances
Pcpn: Equal Chances
Normal Precip (liquid):
• Mar 1 – 2 inches
• Apr – 1.5 to ~2 inches
• May – 3 to 4 inches
http://www.cpcpara.ncep.noaa.gov/
Ocean and Atmospheric Influences on
MN Weather Patterns
 Conditions in the east Pacific are still considered ENSO Neutral this week,
though there is a 65% chance of a weak El Nino later this winter and spring.
Pacific Ocean water temperatures are expected to be about 0.5 to 1.0
degrees above normal. However, weak El Nino conditions do not have a
strong signal on precipitation patterns over the upper midwest.
 “Equal chances” seems about right for the upcoming winter.
Typical El Nino Precipitation
January and February – No clear signal in departure from normal
Typical El Nino Precipitation
March – No clear signal; April tends to be a little drier than normal
Summer months (not shown) – mixed bag, some wetter, some drier
Environmental Canada Forecasts
Jan, Feb, Mar -- Precipitation
Chance of above normal
pcpn to the northwest
http://www.weatheroffice.gc.ca/saisons/index_e.html#forecasts
Environmental Canada Forecasts
Jan, Feb, Mar -- Temperatures
Increased chances of below
normal temperatures nearby
http://www.weatheroffice.gc.ca/saisons/index_e.html#forecasts
Weather and Hydrologic Discussion
 Weather review for mid-late 2013 (precipitation and
temperatures)
 Current Conditions (Snowpack)
 Winter Short and Long range outlooks
 Drought outlook
 Hydrologic long range outlook for Island Lake
Reservoir
Drought Information
Change from normal to D0 (abnormally dry) in the region
Drought Information
Drought outlook: Little change through the winter for our area of interest
Weather and Hydrologic Discussion
 Weather review for mid-late 2013 (precipitation and
temperatures)
 Current Conditions (Snowpack)
 Winter Short and Long range outlooks
 Drought outlook
 Hydrologic long range outlook for Island Lake
Reservoir
Soil Moisture Components in Basin
• SWE -- very low, but early
• UZ (Upper layers): Little
free water, tension water
in the lower half of normal
• LZ (Lower layers): tension
water low, free water
normal
• ADI (Above ground): just
below normal
Chance of Reaching Refill Demands
(Normal Operating Conditions)
Summary: using “normal” condition operating rules, we have
a 20-30% chance of reaching target pool level by June 1st
(vs. normal chance of 60%)
Lower confidence than average
Chance of Reaching Refill Demands
(Dry Operating Conditions)
Summary: using “dry” condition operating rules, we have a
65% chance of reaching target pool level by July 15th
(vs. normal chance of 80%)
Close to average confidence
Summary
 Precipitation – Slightly below normal for the past 6 months
 Temperatures – Temperatures have been around normal.
 Drought / Soil Conditions– Slight degradation to D0
 Short Range outlook (Jan) – Nothing spectacular either way
 Longer Range – No strong indicators to forecast above or below
normal temperatures or precipitation
 Hydrologic Outlook – Confidence is lower than average for
successful fill in normal (20-30%) operating conditions; much
more confident (65%) at dry operating conditions