National Weather Service Text Product Display

Flood Potential Outlook
Issued by NWS Boise, ID
Versions: 1
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210600-

WATER SUPPLY OUTLOOK
NATIONAL WEATHER SERVICE
215 PM MDT FRI APR 19 2013

...IDAHO WATER SUPPLY AND SPRING FLOOD OUTLOOK AS OF APRIL 2013...

...NEAR NORMAL TO BELOW NORMAL RUNOFF VOLUMES EXPECTED FOR
IDAHO...
...SPRING FLOOD RISK FOR NORTHERN IDAHO IS NEAR AVERAGE...
...SPRING FLOOD RISK FOR SOUTHERN IDAHO IS GENERALLY BELOW AVERAGE...

THE NATIONAL WEATHER SERVICE WATER SUPPLY OUTLOOK FOR IDAHO FOR THE
2013 WATER YEAR PROJECTS NEAR NORMAL TO BELOW NORMAL RUNOFF VOLUMES
ACROSS THE STATE AS OF APRIL 19. WATER SUPPLY PROJECTIONS ARE MOST
FAVORABLE FOR THE NORTHERN PORTION OF THE STATE...AND BECOME
PROGRESSIVELY LESS FAVORABLE ACROSS CENTRAL AND SOUTHERN IDAHO.

THE RECENT COOL AND UNSETTLED WEATHER ACROSS IDAHO HAS BEEN
BENEFICIAL IN PRESERVING THE EXISTING SNOWPACK...AND EVEN ADDING TO
THE SNOWPACK IN SOME AREAS. HOWEVER...THE POOR MID AND LOW ELEVATION
SNOWPACK THAT WAS PREVALENT ACROSS MUCH OF SOUTHERN IDAHO THROUGH
THE WINTER HAS SET THE STAGE FOR BELOW NORMAL RUNOFF VOLUMES FOR THE
SOUTHERN PORTION OF THE STATE...ALONG WITH A BELOW AVERAGE SPRING
FLOOD RISK DUE TO SNOWMELT. BETTER SNOW CONDITIONS ACROSS NORTHERN
IDAHO SUPPORT NEAR NORMAL RUNOFF VOLUME FORECASTS AND ABOUT AVERAGE
SPRING FLOOD RISK DUE TO SNOWMELT.

AS WE TRANSITION TO WARMER WEATHER...REMEMBER THAT SPRING FLOODING
IS OFTEN THE RESULT OF SPRING RAINS COMBINED WITH SNOWMELT. IT IS
NOT ALWAYS POSSIBLE TO FORECAST SPECIFIC RAIN STORMS...OR RAIN ON
SNOW EVENTS MORE THAN 4 TO 7 DAYS INTO THE FUTURE. THEREFORE...SHORT
RANGE RIVER FORECASTS SHOULD BE MONITORED CLOSELY IF A RAIN EVENT
OCCURS. DETAILS REGARDING POSSIBLE OR RESULTING FLOODING WILL BE
AVAILABLE IN SHORT TERM OUTLOOKS...FLOOD WATCHES AND FLOOD WARNINGS
ISSUED BY THE NATIONAL WEATHER SERVICE.

REFER TO SECTIONS BELOW AND LINKS PROVIDED FOR THE LATEST DETAILS
REGARDING WATER SUPPLY FORECASTS FOR SPECIFIC LOCATIONS...
SNOWPACK...PRECIPITATION...RESERVOIR CONDITIONS...DROUGHT...AND
LONG TERM WEATHER OUTLOOKS.


WATER SUPPLY FORECASTS...

WATER SUPPLY FORECASTS ISSUED BY THE NORTHWEST RIVER FORECAST CENTER
AND THE COLORADO BASIN RIVER FORECAST CENTER ARE ISSUED
FREQUENTLY...ON EITHER A WEEKLY OR DAILY BASIS.

FOR THE LATEST WATER SUPPLY FORECASTS FOR IDAHO PLEASE REFER TO THE
FOLLOWING WEB SITES.

NATIONAL WEATHER SERVICE-NORTHWEST RIVER FORECAST CENTER
WWW.NWRFC.NOAA.GOV/WS

NATIONAL WEATHER SERVICE-COLORADO BASIN RIVER FORECAST CENTER
WWW.CBRFC.NOAA.GOV/GMAP/CMAP2.PHP?CON=WSUP

USDA-NATURAL RESOURCES CONSERVATION SERVICE
WWW.ID.NRCS.USDA.GOV/SNOW/WATERSUPPLY


SNOWPACK INFORMATION...

BASIN SNOWPACK ACROSS IDAHO AS OF APRIL 19...RANGED FROM 34 PERCENT
OF NORMAL IN THE OWYHEE BASIN TO AROUND 100 PERCENT OF NORMAL IN THE
SALMON FALLS BASIN...GOOSE CREEK BASIN...RAFT RIVER BASIN...SNAKE
BASIN ABOVE PALISADES...AND NORTHERN PANHANDLE REGION. SNOWPACK IS
VERY ELEVATION DEPENDENT IN SOME BASINS...PARTICULARLY ACROSS
SOUTHERN IDAHO...WITH HIGHER ELEVATIONS CARRYING THE SNOWPACK
PERCENTAGES...WHILE LOWER PORTIONS OF THE BASINS ARE LAGGING...OR
EVEN COMPLETELY MELTED IN SOME CASES.

CURRENT DAY SNOW WATER EQUIVALENT AND PERCENT OF NORMAL SNOWPACK
INFORMATION CAN BE FOUND AT THE FOLLOWING WEB SITES.

NATIONAL WEATHER SERVICE-NORTHWEST RIVER FORECAST CENTER
WWW.NWRFC.NOAA.GOV/SNOW

NATIONAL WEATHER SERVICE-COLORADO BASIN RIVER FORECAST CENTER
WWW.CBRFC.NOAA.GOV/GMAP/CMAP2.PHP?CON=SNOW

NATIONAL WEATHER SERVICE-NATIONAL HYDROLOGIC REMOTE SENSING CENTER
WWW.NOHRSC.NWS.GOV

USDA-NATURAL RESOURCES CONSERVATION SERVICE
WWW.ID.NRCS.USDA.GOV/SNOW/DATA/CURRENT.HTML


RESERVOIR INFORMATION...

MOST RESERVOIRS IN IDAHO ARE HOLDING AROUND AVERAGE STORAGE. THERE
ARE SOME EXCEPTIONS ACROSS SOUTHERN IDAHO...WHERE RESERVOIR STORAGE
IS ONLY ABOUT 50 TO 75 PERCENT OF AVERAGE.

THE LATEST RESERVOIR STORAGE INFORMATION CAN BE FOUND AT THE
FOLLOWING WEB SITES

BUREAU OF RECLAMATION RESERVOIR STORAGE
WWW.USBR.GOV/PN/HYDROMET/SELECT.HTML

USDA-NATURAL RESOURCES CONSERVATION SERVICE
WWW.WCC.NRCS.USDA.GOV/CGIBIN/RESV-GRAPH.PL?STATE=ID


DROUGHT CONDITIONS...

ACCORDING TO THE U.S. DROUGHT MONITOR...AS OF APRIL 16...MODERATE
DROUGHT CONDITIONS EXIST ACROSS MUCH OF SOUTHEAST IDAHO...AND ACROSS
THE TREASURE VALLEY AND PORTIONS OF THE OWYHEE MOUNTAINS IN
SOUTHWEST IDAHO.

THE LATEST DROUGHT CONDITIONS ACROSS THE REGION CAN BE FOUND AT THE
FOLLOWING WEB SITES.

U.S. DROUGHT MONITOR
WWW.DROUGHTMONITOR.UNL.EDU

U.S. DROUGHT PORTAL
WWW.DROUGHT.GOV


PEAK FLOW FORECASTS...

THE LATEST PEAK FLOW FORECASTS CAN BE FOUND AT THE FOLLOWING WEB
SITES.

NORTHWEST RIVER FORECAST CENTER PEAK FLOW
WWW.NWRFC.NOAA.GOV/PEAK

COLORADO BASIN RIVER FORECAST CENTER PEAK FLOW
WWW.CBRFC.NOAA.GOV/GMAP/LIST/LIST.PHP?TYPE=PEAK


TEMPERATURE AND PRECIPITATION OUTLOOKS...

ACCORDING TO THE CLIMATE PREDICTION CENTER OUTLOOK...FOR THE MONTH
OF MAY...PROBABILITIES FAVOR ABOVE NORMAL TEMPERATURES ACROSS
SOUTHERN IDAHO...WITH EQUAL CHANCES OF BELOW NORMAL...NORMAL...OR
ABOVE NORMAL TEMPERATURES ACROSS NORTHERN IDAHO. MEANWHILE...
PROBABILITIES FAVOR BELOW NORMAL PRECIPITATION IN MAY FOR NORTHERN
IDAHO...AND EQUAL CHANCES OF BELOW NORMAL...NORMAL...OR ABOVE
NORMAL PRECIPITATION FOR SOUTHERN IDAHO.

THE LATEST LONG RANGE AND SEASONAL OUTLOOKS ISSUED BY THE NATIONAL
WEATHER SERVICE CLIMATE PREDICTION CENTER CAN BE FOUND AT THE
FOLLOWING WEB SITE.

WWW.CPC.NCEP.NOAA.GOV

$$

TAL
National Weather Service Weather Forecast Office
