Alert archive / Idaho / Flash Flood Warnings in 2014

Flash Flood Warning 7, NWS Boise, ID

August 4, 2014Boise County, Elmore County, Idaho

NWS Boise, ID issued this flash flood warning at Aug 4, 2014, 3:58 PM MDT for Boise County, Elmore County, Idaho. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 4, 2014, 3:58 PM MDT (21:58 UTC)
Expired: Aug 4, 2014, 9:45 PM MDT
In force: 6 hr
Issued by: NWS Boise, ID
Area: Storm-based polygon
Flood severity: None

Counties Boise County, ID, Elmore County, ID

The radar

The Boise radar (KCBX), 51 km from the middle of the area, began a volume at 21:58 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Boise Airport, ID (KBOI), launched 12:00Z, 10.0 hours before the alert went out and 50 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 3 J/kg
Mixed-layer CIN: -201 J/kg
Mixed-layer LCL: 2916 m above ground
0-6 km bulk shear: 4 kt
0-1 km storm-relative helicity: -69 m²/s²
0-3 km storm-relative helicity: 48 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

788 
WGUS55 KBOI 042158
FFWBOI
IDC015-039-050345-
/O.NEW.KBOI.FF.W.0007.140804T2158Z-140805T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BOISE ID
358 PM MDT MON AUG 4 2014

THE NATIONAL WEATHER SERVICE IN BOISE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTH CENTRAL BOISE COUNTY IN WEST CENTRAL IDAHO...
  CENTRAL ELMORE COUNTY IN SOUTHWEST IDAHO...

* UNTIL 945 PM MDT
    
* AT 350 PM MDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING
  HEAVY RAIN ACROSS THE WARNED AREA. FLASH FLOODING IS EXPECTED TO 
  BEGIN SHORTLY. THIS AREA HAS RECEIVED HEAVY RAINFALL OVER THE LAST 
  FEW DAYS WITH SEVERAL REPORTS OF FLASH FLOODING...LAND SLIDES AND 
  ROAD WASHOUTS. EXCESSIVE RAINFALL OVER THE PONY COMPLEX...ELK 
  COMPLEX BURN SCARS AS WELL AS HIGHWAY 20 AND COUNTY ROADS NEAR 
  ANDERSON RANCH DAM WILL RESULT IN FLASH FLOODING AND DEBRIS FLOW. 
  THE DEBRIS FLOW CAN CONSIST OF  ROCK...MUD...VEGETATION AND OTHER 
  LOOSE MATERIALS. PLEASE USE EXTREME CAUTION IF YOU ARE IN THE 
  WARNING AREA. 

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  PINE...PRAIRIE...ANDERSON DAM...ARROWROCK RESERVOIR...ANDERSON
  RANCH RESERVOIR...DANSKIN PEAK...TWIN SPRINGS...ARROWROCK DAM...
  ROCKY BAR...TRINITY LAKES...FEATHERVILLE...DUTCH CREEK GUARD
  STATION...JAMES CREEK SUMMIT...LITTLE CAMAS RESERVOIR AND LUCKY
  PEAK RESERVOIR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

&&

LAT...LON 4335 11589 4330 11552 4333 11514 4390 11518
      4361 11598

$$

JDS

2 follow-up statements

085 
WGUS75 KBOI 050023
FFSBOI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BOISE ID
623 PM MDT MON AUG 4 2014

IDC015-039-050345-
/O.CON.KBOI.FF.W.0007.000000T0000Z-140805T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BOISE ID-ELMORE ID-
623 PM MDT MON AUG 4 2014

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 945 PM MDT FOR
SOUTH CENTRAL BOISE AND CENTRAL ELMORE COUNTIES...

AT 619 PM MDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING 
HEAVY RAIN ACROSS THE WARNED AREA.  RAINFALL RATES OF UP TO 1 INCH 
PER HOUR HAVE BEEN REPORTED AT CENTERVILLE. THESE STORMS WILL BE 
MOVING THROUGH THE PONY COMPLEX...ELK COMPLEX BURN SCARS AS WELL AS 
HIGHWAY 20 AND COUNTY ROADS NEAR ANDERSON RANCH DAM IN THE NEXT 
HOUR. PLEASE USE EXTREME CAUTION IF YOU ARE IN THE WARNING AREA. 

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
PINE...PRAIRIE...ANDERSON DAM...ARROWROCK RESERVOIR...ANDERSON RANCH
RESERVOIR...DANSKIN PEAK...TWIN SPRINGS...ARROWROCK DAM...ROCKY
BAR...TRINITY LAKES...FEATHERVILLE...DUTCH CREEK GUARD STATION...
JAMES CREEK SUMMIT...LITTLE CAMAS RESERVOIR AND LUCKY PEAK RESERVOIR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

TURN AROUND...DONT DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

&&

LAT...LON 4335 11589 4330 11552 4333 11514 4390 11518
      4361 11598

$$

JDS

060 
WGUS75 KBOI 050313
FFSBOI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BOISE ID
913 PM MDT MON AUG 4 2014

IDC015-039-050321-
/O.CAN.KBOI.FF.W.0007.000000T0000Z-140805T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BOISE ID-ELMORE ID-
913 PM MDT MON AUG 4 2014

...THE FLASH FLOOD WARNING FOR SOUTH CENTRAL BOISE AND CENTRAL ELMORE
COUNTIES IS CANCELLED...

THE HEAVY RAIN HAS ENDED...AND FLOODING IS NO LONGER EXPECTED TO 
POSE A THREAT. RURAL ROADS COULD BE WASHED OUT OR FLOODED. PLEASE 
USE CAUTION IF TRAVELING IN THIS AREA TONIGHT. MORE HEAVY RAIN IS 
EXPECTED IN THE BOISE MOUNTAINS ON TUESDAY AND WEDNESDAY.

LAT...LON 4335 11589 4330 11552 4333 11514 4390 11518
      4361 11598

$$

JDS

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Boise, ID wrote its last area forecast discussion before this flash flood warning went out at Aug 4, 2:48 PM MDT, 1 hour 10 minutes earlier.

Area forecast discussion, Aug 4, 2:48 PM MDT, 1 hour 10 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
248 PM MDT MON AUG 4 2014

.SHORT TERM...TONIGHT THROUGH WEDNESDAY...VERY MOIST DEFORMATION
AXIS HAS REACHED SOUTH-CENTRAL IDAHO. LATEST RADAR LOOPS INDICATE
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE BOISE/WEST
CENTRAL MTNS...SOUTH TO THE NEVADA BORDER AND WEST INTO SOUTHERN
MALHEUR COUNTY. SO FAR...THE CONVECTION IS NOT THAT IMPRESSIVE
ALTHOUGH RAINFALL RATES OF UP TO 0.5 INCHES PER HOUR WERE
INDICATED WITH THE STRONGER CELLS. THERE ARE STILL SEVERAL HOURS
OF HEATING LEFT TO INITIATE DEEPER CONVECTION...AND THUS THE FLASH
FLOOD THREAT ASSOCIATED WITH THUNDERSTORMS WILL CONTINUE MAINLY
FOR PORTIONS OF SW IDAHO. MODELS CONTINUE TO SHOW THAT THE MOIST
AND UNSTABLE DEFORMATION AXIS WILL REMAIN SITUATED ACROSS MUCH OF
SW IDAHO AND PORTIONS OF SE OREGON THROUGH TUESDAY. THE MODELS
DIVERGE AFTER THAT AS THE NAM SHIFTS THE MOISTURE EAST OF THE AREA
QUICKER THAN THE GFS AND ECMWF. THE FORECAST WILL REFLECT A BLEND
OF THE SLOWER GFS/ECMWF WHICH HOLDS THE MOISTURE IN PLACE THROUGH
WEDNESDAY. THE FLASH FLOOD WATCHES THAT ARE CURRENTLY IN EFFECT
WILL CONTINUE THROUGH TUESDAY EVENING. THE WATCHES MAY NEED TO BE
EXTENDED INTO WEDNESDAY IF FUTURE MODEL RUNS CONTINUE TO SUPPORT A
SLOWER DEPARTURE OF THE MOISTURE. TEMPERATURE CONTRASTS ACROSS
THE CWA WILL CONTINUE...WITH BELOW NORMAL TEMPERATURES CENTERED
IN THE WESTERN MAGIC VALLEY TO NEAR NORMAL TEMPERATURES IN THE
DRIER AIR MASS...WHICH INCLUDES MOST OF SE OREGON.

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...LATEST MODEL RUNS
KEEP THE MONSOONAL MOISTURE OVER THE AREA AND POSSIBLE FLASH FLOOD
THREAT THROUGH THURSDAY. THIS SYSTEM WILL SLOWLY EXIT THE AREA BY
FRIDAY. RESIDUAL MOISTURE WILL KEEP A THREAT OF AFTERNOON SHOWERS
AND THUNDERSTORMS MAINLY OVER THE HIGHER TERRAIN THROUGH MONDAY AS
A WEAK TROUGH LINGERS OFF THE NORTHERN CA COAST THROUGH MONDAY.
SLIGHTLY BELOW NORMAL TEMPERATURES WILL GRADUALLY WARM TO NORMAL
BY SATURDAY AND ABOVE NORMAL BY SUNDAY AND BEYOND.

&&

.AVIATION...VFR. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS.
SURFACE WINDS EASTERLY 5-15KT...EXCEPT IN VICINITY OF
THUNDERSTORMS WHERE GUSTS TO 40KT POSSIBLE. WINDS ALOFT AT 10K FT
MSL...NORTHEAST 5-15KT.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...FLASH FLOOD WATCH THROUGH TUESDAY EVENING IDZ013>016-028>030.
OR...NONE.

&&

WEATHER.GOV/BOISE

SHORT TERM...BW
LONG TERM....KA/AB
AVIATION.....KA

The office that day

Everything else NWS Boise, ID issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 3, 6:07 PM MDT	Flash Flood Warning	BOI	Camas, Elmore	3 hr
Aug 3, 6:44 PM MDT	Severe Thunderstorm Warning	BOI	Owyhee	27 min
Aug 4, 5:14 PM MDT	Flash Flood Warning	BOI	Boise, Elmore	4 hr

Nearby

Flash Flood Warnings in Idaho, 2014 Every flash flood warning in 2014

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.