Alert archive / Idaho / Flash Flood Warnings in 2005

Flash Flood Warning 2, NWS Boise, ID

May 6, 2005Canyon County, Idaho

NWS Boise, ID issued this flash flood warning at May 6, 2005, 3:50 PM MDT for Canyon County, Idaho. It was in force for 85 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 6, 2005, 3:50 PM MDT (21:50 UTC)
Expired
May 6, 2005, 5:15 PM MDT
In force
85 min
Issued by
NWS Boise, ID
Area
Counties, with a storm outline in the text

County Canyon County, ID

The radar

The Boise radar (KCBX), 39 km from the middle of the area, began a volume at 21:50 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, 9.8 hours before the alert went out and 37 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-pSkew-T log-p diagram, Boise Airport, ID at 12:00Z on 2005-05-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 36 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Boise Airport, ID at 12:00Z on 2005-05-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 30 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
36 J/kg
Mixed-layer CIN
-31 J/kg
Mixed-layer LCL
879 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
30 m²/s²
0-3 km storm-relative helicity
80 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.

000 
WGUS55 KBOI 062151
FFWBOI
IDC027-062315-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BOISE ID
350 PM MDT FRI MAY 6 2005

THE NATIONAL WEATHER SERVICE IN BOISE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL CANYON COUNTY IN SOUTHWEST IDAHO
  THIS INCLUDES THE CITY OF CALDWELL

* UNTIL 515 PM MDT

* AT 345 PM MDT...FLASH FLOODING WAS REPORTED FROM A THUNDERSTORM 
OVER THE WARNED AREA.

THE SOUTHEASTERN PARTS OF CALWELL HAVE THE HIGHEST RISK AT THIS TIME.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES
AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.

FLOODING IS OCCURRING OR IS IMMINENT. MOST FLOOD RELATED DEATHS OCCUR
IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS WATER COVERED BRIDGES...
DIPS...OR LOW WATER CROSSINGS. NEVER TRY TO CROSS A FLOWING STREAM...
EVEN A SMALL ONE...ON FOOT. TO ESCAPE RISING WATER MOVE UP TO HIGHER
GROUND.

LAT...LON 4367 11652 4357 11657 4368 11681 4378 11679
      4377 11660

$$

JPB
2 follow-up statements
000 
WGUS75 KBOI 062217
FFSBOI
IDC027-062315-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BOISE ID
415 PM MDT FRI MAY 6 2005

...A FLASH FLOOD WARNING CONTINUES UNTIL 515 PM MDT FOR CENTRAL 
CANYON COUNTY...

AT 415 PM MDT...A THUNDERSTORM PRODUCING FLASH FLOODING WAS STILL 
OVER THE WARNED AREA.  CALDWELL AIRPORT HAS REPORTED 1.10 INCHES OF 
RAIN IN LESS THAN ONE HOUR.  RADAR INDICATES THAT THE HEAVIEST RAIN 
OCCURRED JUST EAST OF THE CITY.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO THE CITY OF 
CALDWELL. FLOODING IS ALSO LIKELY ALONG MASON CREEK...SOLOMAN DRAIN 
AND NOBLE DRAIN.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL 
CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES
AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.

MOST FLOOD RELATED DEATHS OCCUR IN AUTOMOBILES. DO NOT ATTEMPT TO 
CROSS WATER COVERED BRIDGES...DIPS...OR LOW WATER CROSSINGS. NEVER 
TRY TO CROSS A FLOWING STREAM...EVEN A SMALL ONE...ON FOOT. TO 
ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.

LAT...LON 4367 11652 4357 11657 4368 11681 4378 11679
      4377 11660

$$

JPB
000 
WGUS75 KBOI 062300
FFSBOI
IDC027-062315-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BOISE ID
452 PM MDT FRI MAY 6 2005

...A FLASH FLOOD WARNING CONTINUES UNTIL 515 PM MDT FOR CENTRAL 
CANYON COUNTY...

AT 450 PM MDT RAIN WAS TAPERING OFF WITHIN THE WARNING AREA BUT 
THERE CONTINUE TO BE REPORTS OF FLASH FLOODING IN AND NEAR CALDWELL. 
THE CANYON COUNTY SHERIFF/S DEPARTMENT HAS RELAYED REPORTS OF MORE 
THAN 1 FOOT OF WATER FLOWING OVER CONWAY AND TEN DAVIS ROAD. 
PORTIONS OF MARKET ROAD BETWEEN I-84 AND SANDHOLLOW HAVE BEEN WASHED 
OUT.  STANDING WATER WAS ALSO BEEN REPORTED IN PORTIONS OF DOWNTOWN 
CALDWELL ON CALDWELL BOULEVARD.

MOST FLOOD RELATED DEATHS OCCUR IN AUTOMOBILES. DO NOT ATTEMPT TO 
CROSS WATER COVERED BRIDGES...DIPS...OR LOW WATER CROSSINGS. NEVER 
TRY TO CROSS A FLOWING STREAM...EVEN A SMALL ONE...ON FOOT. TO 
ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.

LAT...LON 4367 11652 4357 11657 4368 11681 4378 11679
      4377 11660

$$

JPB

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 May 6, 2:42 PM MDT, 1 hour 8 minutes earlier.

Area forecast discussion, May 6, 2:42 PM MDT, 1 hour 8 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
245 PM FRI MAY 6 2005

.SHORT TERM...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH MUCH OF
THE EVENING AS SHOWERS/STORMS CONVERGE OVER SOUTHWEST IDAHO.
GREATEST INSTABILITY AND LIFT REMAINS TO OUR EAST AND SOUTHEAST BUT
ATMOSPHERE ALSO DESTABILIZING OVER SOUTHWEST IDAHO AS WELL.
CONVECTIVE TEMP HAS BEEN REALIZED IN SOUTHWEST IDAHO AND
SHOWERS/THUNDERSTORMS RESPONDING. HARD TO NAIL DOWN ANY ONE AREA
RIPE FOR FLASH FLOODING POTENTIAL BUT STILL FEEL BAKER COUNTY OREGON
COULD BE A THREAT IF CONVECTION COULD ADVECT INTO THE AREA OF
PERSISTENT STRATIFORM RAIN WHICH HAS BEEN PARKED OVER THIS AREA FOR
MANY HOURS.  OTHERWISE...SOUTHWEST HIGHLANDS OR BOISE MOUNTAINS MAY
BE AREAS TO WATCH WITH SOIL CONDITIONS NOW RIPENED UP FROM
YESTERDAYS EVENT.  COULD EVEN SEE MORE URBAN FLOODING IN THE
TREASURE VALLEY IF STORMS ROLL IN THIS EVENING. VERY WEAK FLOW ALOFT
UNDER THE UPPER LOW WILL ONLY ACT TO ENHANCE HEAVY RAIN POTENTIAL
WITH SLOW MOVING EXCELLENT RAIN EFFICIENT STORMS. MODELS INDICATE
MAIN COMMA HEAD OF MOISTURE STAYS OVER THE AREA FOR MUCH OF THE
NIGHT THEN EVENTUALLY MOVES OFF TO THE EAST AND WEAKENS SATURDAY.  DO
NOT FEEL SEVERE STORMS ARE MUCH OF A THREAT THIS EVENING WITH LOW
SHEAR MOIST ENVIRONMENT...SO WILL HIGHLIGHT HEAVY RAIN POTENTIAL
AGAIN IN EVENING FORECASTS. BRIEF CLEARING MOVING ACROSS THE REGION
FROM WEST TO EAST SATURDAY AFTERNOON AND LASTING FOR THE FIRST HALF
OF MOTHERS DAY.  SUNDAY FOR THE MOST PART LOOKS LIKE A GOOD DAY
WITH RAIN HOLDING OFF AHEAD OF NEXT SYSTEM UNTIL EARLY MONDAY
MORNING.  THIS NEW WAVE MOVES INTO THE AREA DURING MONDAY WITH
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS AHEAD OF YET ANOTHER
CLOSED LOW SYSTEM.  TEMPERATURES TO REMAIN FAIRLY COOL FOR MAY UNDER
MOIST ACTIVE SHOWERY REGIME.

LONG TERM...FOR SOUTHWEST IDAHO AND SOUTHEAST OREGON MONDAY NIGHT
THROUGH FRIDAY. MODEL CONSISTENCY CONTINUES TO BE GOOD ALTHOUGH
THERE IS A TREND TOWARD SLIGHTLY SLOWER DEPARTURE OF THE UPPER LEVEL
TROUGH WEDNESDAY AND WEDNESDAY NIGHT. THIS COULD MEAN SLIGHTLY
COOLER MAX TEMPERATURES THURSDAY THAN THE CURRENT FORECAST. HOWEVER
FOR NOW THERE ARE NO UPDATES IN TEMPERATURES OR POPS. THE BEST
CHANCES OF PRECIPITATION WILL BE TUESDAY WITH THE UPPER LEVEL LOW
JUST MOVING IN OVER THE INTERMOUNTAIN REGION. PROBABILITIES
DECREASE WEDNESDAY AND DROP QUITE LOW FOR THURSDAY AND FRIDAY UNDER
A BUILDING UPPER LEVEL RIDGE. TEMPERATURES WILL BE A FEW DEGREES
BELOW NORMAL TUESDAY AND WEDNESDAY AND RETURN TO NEAR NORMAL FOR
THURSDAY AND FRIDAY.

&&

.AVIATION...WITH MOIST UNSTABLE AIR AND SURFACE LOW PRESSURE NEARLY
STATIONARY OVER THE CWFA AREAS OF SHOWERS WILL CONTINUE THROUGH
SATURDAY MORNING WITH SCATTERED MVFR AND LOCAL IFR CEILINGS AND
MOUNTAIN OBSCURATION. WIDELY SCATTERED THUNDERSTORMS WILL CONTINUE
THROUGH THE EVENING UNTIL ABOUT 05Z. THESE HAVE THE POTENTIAL FOR
LOCAL HEAVY RAINS BRIEFLY RESTRICTING VISIBILITIES. LOCAL VALLEY FOG
IS POSSIBLE AFTER 06Z.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
.ID...FLASH FLOOD WATCH 3PM MDT UNTIL 10PM MDT FOR ZONES 11 12 13 14
       15 AND 29.
.OR...FLASH FLOOD WATCH 3PM MDT (2PM PDT) UNTIL 10 PM MDT (9PM PDT)
       FOR ZNS 62 63 AND 64.

WEATHER.GOV/BOISE

DISCUSSION...GS
AVIATION.....JT
LONG TERM....JT
Hazardous weather outlook, May 6, 5:31 AM MDT, 10 hours 19 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BOISE ID
531 AM MDT FRI MAY 6 2005

IDZ011>016-028>030-ORZ061>064-071145-
WEST CENTRAL MOUNTAINS-LOWER TREASURE VALLEY ID-BOISE MOUNTAINS-
UPPER TREASURE VALLEY-SOUTHWEST HIGHLANDS-WESTERN MAGIC VALLEY-
CAMAS PRAIRIE-OWYHEE MOUNTAINS-SOUTHERN TWIN FALLS COUNTY-
HARNEY COUNTY-BAKER COUNTY-MALHEUR COUNTY-
LOWER TREASURE VALLEY OR-
431 AM PDT FRI MAY 6 2005 /531 AM MDT FRI MAY 6 2005/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
IDAHO...SOUTHWEST IDAHO...WEST CENTRAL IDAHO...SOUTHEAST OREGON
AND NORTHEAST OREGON.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER EXPECTED AT THIS TIME.

The office that day

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

IssuedProductOfficeCountiesLasted
May 5, 6:11 PM MDTSevere Thunderstorm WarningBOIElmore, Gooding, Twin Falls34 min
May 5, 7:22 PM MDTSevere Thunderstorm WarningBOIAda, Canyon38 min
May 5, 8:25 PM MDTFlash Flood WarningBOIAda65 min
May 6, 4:58 PM MDTFlash Flood WarningBOICanyon, Payette92 min
May 6, 5:15 PM MDTFlash Flood WarningBOICanyon60 min

Nearby

Flash Flood Warnings in Idaho, 2005Every flash flood warning in 2005

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.