t2mathew@blm.gov

Antecedent Conditions Weather Patterns of 2014-2015 (Fall through Early Spring) Temperature, RH and Wind 2012 (Severe Fire Season) vs. 2015 (So Far) Current Drought Conditions and Comparisons Precipitation Since January 1st

Prediction Predictors

General SST Anomalies ENSO PDO MJO

ENSO Forecast Final Thoughts and Considerations for the remainder Spring 2015 and Core Fire

Season

Dry

Wet

Weak Positive ENSO

H

L

L

L

L

L

Shift Westward

Wet

Dry

Dry

Wet

Weak Positive ENSO

H

L

L L

L

L

Dry

Below Average temperatures noted across much of the RMA Since in 2014

Warmer conditions in 2015 for the same period. A lot of variability, however.

Warm West

Cold East

515

25

35

45

55

65

75

85

95

1 9 17 25 2 10 18 26 5 13 21 29 6 14 22 30 8 16 24

Tem

pe

ratu

re

Red Canyon RAWS (4644) Maximum Temperature Comparisons Jan May 2012 vs. 2015

2012

2015

Significant Warm Period March 2012 and May 2012

A lot of Temperature Variability Max Range of 7F January 4 and a Max of 68 F January 27

2012 Ave: 48.5F 2015 Ave: 46.9F

0 0

14

6 6

13

8

6

11

0 0

2 2

0

2

4

6

8

10

12

14

16

18

20

22

24

Janu

ary

Feb

ruary

March

Ap

ril

May

Jun

e

July

Au

gu

st

Sep

temb

er

Nu

mb

er

of

Day

s (F

req

uen

cy)

Red Canyon RAWS Wind-RH Index (Wind Gusts 25 mph+ and RH < 20%) Jan-Sep 2012 vs 2015

Wind RH 2012

Wind RH 2015

26 Days in March through May 2012 4 Days meet this criteria so far for 2015

515

25

35

45

55

65

75

85

1 8 15 22 29 5 12 19 26 4 11 18 25 1 8 15 22 29

Tem

pera

ture

Sugar Loaf RAWS (6733)

Maximum Temperature Comparisons January - May 2012 vs. 2015

2012

2015

A lot of Temperature Variability Max Range of 13F February 22 and a Max of 77 F March 16

Significant Warm Period at the end of March 2012 and May 2012

2012 Ave: 52.5F 2015 Ave: 49.6F

13

5

11

8 9

10

0

8

2

5 5 6

1

0

2

4

6

8

10

12

14

16

18

20

22

24

Janu

ary

Feb

ruary

March

Ap

ril

May

Jun

e

July

Au

gu

st

Sep

temb

er

Nu

mb

er

of

Day

s (F

req

uen

cy)

Sugar Loaf RAWS Wind-RH Index (Wind Gusts 25 mph+ and RH

10

20

30

40

50

60

70

80

90

1 9 17 25 2 10 18 26 5 13 21 29 6 14 22 30 8 16 24

Tem

pera

ture

Manchester RAWS (8489)

Maximum Temperature Comparisons Jan -May 2012 vs. 2015

2012

2015

2012 Ave: 50.4F 2015 Ave: 45.8F

A lot of Temperature Variability, similar to Red Canyon

11

9

22

20

14

23

3

8

6

4

7

9

6

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

Janu

ary

Feb

ruary

March

Ap

ril

May

Jun

e

July

Au

gu

st

Sep

temb

er

Nu

mb

er

of

Day

s (F

req

uen

cy)

Manchester RAWS Wind/RH Index (Wind Gusts 25 mph+ and RH

10

20

30

40

50

60

70

80

90

1 9 17 25 2 10 18 26 5 13 21 29 6 14 22 30 8 16 24

Tem

pera

ture

Ladore RAWS (5940)

Maximum Temperature Comparisons Jan -May 2012 vs. 2015

2012

2015

2012 Ave: 48.2F 2015 Ave: 51.2F

Little variability. Just warm!!!!!!!!!!!!

2

0

14 13

20

24

16

13

7

1 1

6 6

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

Janu

ary

Feb

ruary

March

Ap

ril

May

Jun

e

July

Au

gu

st

Sep

temb

er

Nu

mb

er

of

Day

s (F

req

uen

cy)

Ladore RAWS Wind/RH Index (Wind Gusts 25 mph+ and RH

April 1, 2014 vs. April 1, 2015 Black Hills Percent of 30 Year Average SWE

90-Day % of Average PCP 4/6/2015

60-Day % of Average PCP 04/06/2015

February-March, 2015 60-Day Percent of Average Precipitation

April 1, 2014

PDO

ENSO Modoki

Focus over Central Pacific

Drier than average across the western U.S.

Dry Wet

PDO

ENSO Modoki

PDO

ENSO Modoki

MJO Inactive (Little or No Signal)

Tends to be less active during ENSO Positive and Negative Phases

More Active Weather Pattern: Wetter and Cooler Weather Pattern April 8-15, 2015

Wednesday- April 8

Sunday- April 12 Wednesday April 15

L

More Active Weather Pattern For April vs. March.

Sunday- April 12th

Wind L

Sunday- April 16

L

More Active Weather Pattern For April vs. March.

Near Average

Not as wet as the Spring of 2014 Above Average Temperatures

Localized Seasonal Severity

Persistent Dryness,

Heat, Wind in Spring and

Summer

Significant Snowpack And Wet Summer

Conditions

Forecast

Much Above Historic

Average to Above

Below

Much Below

Rocky Mountain Area 2015 Fire Season Outlook

Significant Snowpack Wet Spring Occasional

Dry Summer Periods

2015 Seasonal Fire Potential Outlook Summary Current Climatology Antecedent conditions in 2015 support a more active fire season compared to 2014. Above average temperatures has resulted in an early snowmelt/runoff across much of the Rocky Mountain Area. Much of the RMA Snowpack is in the 60% of average range, with virtually a complete loss of snowpack in the Black Hills (about a month ahead of normal) 30/60/90 Day Percent of Average Precipitation indicate that the driest conditions extend from northwest Colorado, through Wyoming and South Dakota. Southwest and eastern Colorado benefited from several snow events in February and early March, but have experienced below average moisture since. Below average moisture is noted across the plains during the last several weeks as well. The frequency of Combined Strong Wind and Low Humidity Events has been greater than 2014, but less than what was experienced in 2012 (January through early April).

Fuels Carry-over of grass from last years growing season is abundant Earlier than average snowmelt has prematurely exposed heavier fuels (100-hr, 1000-hr) early than average. If drier than average conditions continue, green-up could be minimal and short in duration. Above average temperatures could result in drier fuel conditions emerging before the typical dry periods of late Spring and early Summer.

Considerations and Fire Season Outlook The April/May weather pattern is forecast to be more active across the Rocky Mountain Area than what was experienced in March, with opportunities for beneficial precipitation. Temperatures through the remainder of the spring are forecast to remain above average. Frequency of Wind/Low Humidity events are forecast to remain below 2012 levels, but above 2014. Fire risk will remain elevated until green-up, especially east of the divide (Lower foothills and Plains). These areas will continue to be more susceptible to occasional wind/low humidity events as storms systems move through the region. Severity Indices across the Rocky Mountain Area contrast 2014 values in all categories (Temperature, Precipitation, Snowpack, Wind-RH, and Fuel Dryness), but are still not at the level of 2012 values. Overall, a below average fire season (similar to 2014) is unlikely with Severity Indices supporting a more active fire season.