Drought Information Statement
Issued by NWS Denver/Boulder, CO

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000
AXUS75 KBOU 172201 CCA
DGTBOU
COC001-005-013-014-019-031-035-039-047-049-057-
059-069-073-075-087-093-095-115-117-121-123-300000-

DROUGHT INFORMATION STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
227 PM MST THU NOV 17 2016

...SEVERE DROUGHT HAS BEEN INTRODUCED INTO LARIMER COUNTY IN NORTH
CENTRAL COLORADO AND NORTHWEST LINCOLN COUNTY IN EAST CENTRAL
COLORADO...

SYNOPSIS...

WARMER AND DRIER WEATHER BEGAN IN MID JUNE AND CONTINUED THROUGH MID
NOVEMBER AS HIGH PRESSURE DOMINATED THE ROCKY MOUNTAIN REGION. THIS
YEAR`S COLORADO MOUNTAIN SNOWPACK WAS THE LOWEST MID NOVEMBER
SNOWPACK IN NEARLY 40 YEARS OF RECORD. SOIL MOISTURE AND GRASSES
HAVE CONTINUED TO DRY OUT ESPECIALLY EAST OF THE CONTINENTAL DIVIDE.
THE FASTEST DROUGHT SEVERITY INCREASE THE PAST 5 MONTHS OCCURRED
ALONG THE NORTHERN FRONT RANGE URBAN CORRIDOR AND EAST CENTRAL
PLAINS.

LOCAL AREAS AFFECTED...

ON NOVEMBER 15TH...SEVERE DROUGHT /D2/ WAS INTRODUCED INTO THE FORT
COLLINS...LOVELAND...ESTES PARK...RUSTIC AND THE HIGH FOREST AREAS
TO THE NORTHWEST IN LARIMER COUNTY AND ALSO IN LINCOLN COUNTY
CENTERED AROUND LIMON ON THE U.S. DROUGHT MONITOR. THESE AREAS ARE
IN SEVERE DROUGHT DUE TO LOW PRECIPITATION...MUCH HIGHER THAN
AVERAGE EVAPORATIVE DEMAND AND 6 MONTH SPI VALUES OF -1.5 OR LOWER.
THE STANDARDIZED PRECIPITATION INDEX /SPI/ IS A PROBABILITY INDEX
THAT ONLY CONSIDERS PRECIPITATION. THE SPI WAS DEVELOPED TO MONITOR
POTENTIAL SHORT TERM AGRICULTURAL AND LONG TERM HYDROLOGIC DROUGHT
CONDITIONS. THE MORE NEGATIVE THE SPI VALUE IS...THE FARTHER BELOW
NORMAL PRECIPITATION. SPI VALUES IN THE -1.3 TO -1.5 RANGE ARE
INDICATIVE OF A SEVERE DROUGHT.

THE SPIS FOR OTHER AREAS OF THE EASTERN PLAINS ARE MOSTLY BELOW -1.
MODERATE DROUGHT /D1/ CONDITIONS CONTINUE IN THE MOUNTAINS EAST OF
THE DIVIDE...FRONT RANGE FOOTHILLS AND URBAN CORRIDOR EXTENDING
EASTWARD ACROSS THE EAST CENTRAL PLAINS AND INTO THE EXTREME
NORTHEAST CORNER OF COLORADO. ABNORMALLY DRY CONDITIONS EXTEND
ACROSS THE REMAINDER OF THE NORTHEAST COLORADO PLAINS.

FIRE DANGER IMPACTS...

GRASSES HAVE CONTINUED TO DRY OUT. THIS COMBINED WITH GUSTY WINDS
CAUSED SEVERAL GRASS FIRES TO BREAK OUT ALONG THE URBAN CORRIDOR ON
NOVEMBER 16TH.

AGRICULTURAL IMPACTS...

2016 WAS THE 14TH DRIEST SEPTEMBER THROUGH OCTOBER IN 122 YEARS OF
RECORD IN THE SOUTH PLATTE RIVER BASIN. DUE TO THE LACK OF
PRECIPITATION...THE WINTER WHEAT CROP IS PATCHY AND STRUGGLING. THE
MOST RECENT USDA COLORADO CROP PROGRESS REPORT STATED "VIRTUALLY NO
PRECIPITATION WAS RECEIVED ACROSS THE STATE LAST WEEK...WITH THE
EXCEPTION OF ISOLATED HIGH COUNTRY SNOW SHOWERS. AREAS THAT HAVE NOT
RECEIVED MOISTURE THE PAST SEVERAL MONTHS ARE CRITICALLY STRESSED.
AS WINTER WHEAT CONTINUES TO GROW DURING THE WARM WEATHER...SOIL
MOISTURE IS RAPIDLY DEPLETING AND STANDS ARE NOT RECEIVING
SUFFICIENT MOISTURE TO SUSTAIN THIS GROWTH. ALSO...POOR RANGE
CONDITIONS IN THESE AREAS ARE A CONCERN GOING INTO THE WINTER
MONTHS. OVERALL...SOIL MOISTURE CONTINUES TO DECLINE WITHOUT
ADEQUATE PRECIPITATION TO RECHARGE".

SOIL MOISTURE IS BELOW THE 10TH PERCENTILE (BOTTOM 10%) IN AREAS OF
EASTERN COLORADO. THE DROUGHT CATEGORIES ARE ASSOCIATED WITH
PERCENTILE RANKINGS (HISTORICAL OCCURRENCE). A MODERATE DROUGHT IS
SOMETIMES ASSOCIATED WITH 20TH PERCENTILE (BOTTOM 20% OR 1 IN 5 TO
10 YEARS) AND A SEVERE DROUGHT WITH THE 10TH PERCENTILE (BOTTOM 10%
OR 1 IN 10 TO 20 YEARS).

SNOWPACK AND RESERVOIR STORAGE...

THE MID NOVEMBER MOUNTAIN SNOWPACK WAS THE LOWEST IN NEARLY 40 YEARS
OF RECORD. ALTHOUGH THE SNOWPACK IS OFF TO A SLOW START...IT IS
EXTREMELY EARLY IN THE SNOW ACCUMULATION SEASON. EARLY SNOW LEVELS
ARE NOT A GOOD INDICATOR OF 2017 WATER AVAILABILITY...WITH
SIGNIFICANT INCREASES OCCURRING INTO MARCH AND APRIL. AS OF NOVEMBER
15TH...THE COLORADO HIGH COUNTRY WOULD HAVE TO RECEIVE 114 PERCENT
OF NORMAL SNOWPACK ACCUMULATION FOR THE REMAINDER OF THE SEASON TO
GET TO A NORMAL PEAK BECAUSE OF THE SNOWPACK DEFICIT. THE NOVEMBER
16TH BASIN SNOWPACK WAS ONLY 21 PERCENT OF NORMAL IN THE NORTH
PLATTE BASIN...18 PERCENT OF NORMAL IN THE SOUTH PLATTE BASIN AND A
MEAGER 10 PERCENT OF NORMAL IN THE UPPER COLORADO RIVER BASIN.

RESERVOIR STORAGE CONTINUED TO VERY SLOWLY DECREASE.
HOWEVER...COMBINED RESERVOIR STORAGE REMAINED IN GOOD SHAPE AT 105
AND 106 PERCENT OF AVERAGE...RESPECTIVELY IN THE UPPER COLORADO AND
SOUTH PLATTE BASINS ON NOVEMBER 1ST.

PRECIPITATION/TEMPERATURE OUTLOOK...

THE WEATHER PATTERN HAS CHANGED AS A STORM BRINGS MUCH COLDER
TEMPERATURES AND SNOW SHOWERS TODAY. THE SNOW WILL DECREASE
OVERNIGHT. TOTAL SNOW ACCUMULATIONS IN THE MOUNTAINS WILL RANGE FROM
4 TO 10 INCHES...WITH 1 TO 2 INCHES ACROSS THE NORTHEAST PLAINS. IT
WILL THEN BE DRY AGAIN FRIDAY WITH A WARMING TREND THIS WEEKEND.

THE CPC OUTLOOKS HAVE ABOVE NORMAL TEMPERATURES AND A TILT TOWARD
ABOVE NORMAL PRECIPITATION IN NORTH CENTRAL AND NORTHEAST COLORADO
THE LAST WEEK OF NOVEMBER. THE 30 AND 90 DAY OUTLOOKS HAVE A TILT
TOWARD ABOVE NORMAL TEMPERATURES WITH EQUAL CHANCES OF NEAR...ABOVE
OR BELOW NORMAL PRECIPITATION. THE U.S. SEASONAL DROUGHT OUTLOOK
VALID THROUGH FEBRUARY 28TH 2017 CALLS FOR THE DROUGHT TO PERSIST.

&&

RELATED WEB SITES...

ADDITIONAL INFORMATION ON CURRENT DROUGHT CONDITIONS MAY BE FOUND
AT THE FOLLOWING WEB ADDRESSES /USE LOWER CASE LETTERS/:

LOCAL WEATHER...CLIMATE AND WATER INFORMATION
WWW.WEATHER.GOV/BOU

US DROUGHT MONITOR
DROUGHTMONITOR.UNL.EDU

COLORADO CLIMATE CENTER/NIDIS DROUGHT PRESENTATIONS
CLIMATE.COLOSTATE.EDU/DROUGHT_WEBINAR.PHP

NWS CLIMATE PREDICTION CENTER OUTLOOKS
WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/
WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/EXPERT_ASSESSMENT/
SEASONAL_DROUGHT.PNG

US DEPARTMENT OF AGRICULTURE
HTTP://WWW.CO.NRCS.USDA.GOV/
HTTP://WWW.NASS.USDA.GOV/

CWCB WATER AVAILABILITY TASK FORCE PRESENTATIONS
CWCB.STATE.CO.US/PUBLIC-INFORMATION/FLOOD-WATER-AVAILABILITY-TASK-
FORCES/

ACKNOWLEDGMENTS...

THE DROUGHT MONITOR IS A MULTI-AGENCY EFFORT INVOLVING NOAA`S
NATIONAL WEATHER SERVICE...STATE AND REGIONAL CLIMATE CENTERS...
DEPARTMENT OF AGRICULTURE (USDA) AND THE NATIONAL DROUGHT MITIGATION
CENTER. INFORMATION FOR THIS STATEMENT HAS BEEN GATHERED FROM NWS
AND FAA OBSERVATION SITES...COOPERATIVE NETWORK STATIONS...NATURAL
RESOURCES CONSERVATION SERVICE SNOTEL NETWORK...COCORAHS NETWORK AS
WELL AS COLORADO DIVISION OF WATER RESOURCES... US GEOLOGICAL
SURVEY...BUREAU OF RECLAMATION AND US ARMY CORP OF ENGINEERS STREAM
AND RESERVOIR GAUGES.

QUESTIONS OR COMMENTS...

IF YOU HAVE ANY QUESTIONS OR COMMENTS ABOUT THIS DROUGHT INFORMATION
PLEASE CONTACT...

NATIONAL WEATHER SERVICE
325 BROADWAY
BOULDER CO 80305
303-494-4221

$$
TLH



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