Alert archive / Idaho / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 5, NWS Boise, ID

May 26, 2015Ada County, Canyon County, Idaho

NWS Boise, ID issued this severe thunderstorm warning at May 26, 2015, 9:46 PM MDT for Ada County, Canyon County, Idaho. It was in force for 44 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 26, 2015, 9:46 PM MDT (03:46 UTC)
Expired
May 26, 2015, 10:30 PM MDT
In force
44 min
Issued by
NWS Boise, ID
Area
Storm-based polygon

Counties Ada County, ID, Canyon County, ID

The radar

The Boise radar (KCBX), 20 km from the middle of the area, began a volume at 03:46 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.

The nearest sounding before it

Boise Airport, ID (KBOI), launched 00:00Z, 3.8 hours before the alert went out and 22 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 00:00Z on 2015-05-27Temperature 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 00:00Z on 2015-05-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 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
-23 J/kg
Mixed-layer LCL
2561 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
40 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at May 26, 9:06 PM MDT, 40 minutes earlier.

Area forecast discussion, May 26, 9:06 PM MDT, 40 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
906 PM MDT TUE MAY 26 2015

.DISCUSSION...THUNDERSTORMS CONTINUE ACROSS SOUTHERN MALHEUR
COUNTY INTO OWYHEE COUNTY AS WELL AS THE LOWER TREASURE VALLEY
THIS EVENING. AT 03Z...RADAR IS SHOWING A SMALL AREA OF
THUNDERSTORMS NEAR PARMA...NYSSA AND NEW PLYMOUTH MOVING EAST-
SOUTHEAST TOWARDS MIDDLETON...EMMETT AND CALDWELL. LATEST HIGH-RES
MODELS ARE SHOWING THESE THUNDERSTORMS REACHING THE BOISE METRO
AREA...MAINLY STAR AND EAGLE...IN THE NEXT HOUR OR SO. EXPECT BRIEF
HEAVY RAIN AND LIGHTNING. ISOLATED SHOWERS AND THUNDERSTORMS WILL
CONTINUE OVERNIGHT AS THE UPPER LEVEL LOW PRESSURE SYSTEM SHIFTS
SOUTHWARD TOWARDS THE FORECAST AREA. BY WEDNESDAY AFTERNOON THE
LOW CENTER WILL BE OVER LEWISTON. MORE SHOWERS AND THUNDERSTORMS
ARE EXPECTED EARLY WEDNESDAY AFTERNOON ACROSS MOST OF THE AREA.
CURRENT FORECAST AS THIS COVERED WELL SO NO UPDATE NEEDED.

&&

.AVIATION...VFR. SCATTERED TO ISOLATED SHOWERS BECOMING NUMEROUS
SHOWERS AFTER 18Z MAY 28. ISOLATED THUNDERSTORMS EAST OF A LINE
FROM KBKE TO KREO THROUGH 06Z AND POSSIBLY ACROSS IDAHO MTNS
OVERNIGHT. ISOLATED THUNDERSTORMS REDEVELOPING AFTER 18Z MAY 28.
SURFACE WINDS VARIABLE UP TO 12 KTS EXCEPT STRONGER IN SHOWERS AND
THUNDERSTORMS. WINDS ALOFT NEAR 10K FT MSL...WEST 10-15 KTS.

&&

.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH THURSDAY...UPPER LEVEL LOW WAS
CENTERED OVER ERN WASHINGTON AS OF 18Z. THIS WILL MOVE SLOWLY SE
AND PASS OVER CENTRAL IDAHO OVERNIGHT BEFORE WEAKENING AND
DEPARTING TO THE NE INTO MONTANA BY LATE THU. CONVECTION HAS AGAIN
DEVELOPED ACROSS PORTIONS OF THE CWA...MAINLY ON THE IDAHO SIDE
AND CONCENTRATED IN OWYHEE COUNTY. AS THE LOW MOVES CLOSER
OVERNIGHT...MID-LEVEL TEMPS WILL COOL AND WE EXPECT A BETTER-
THAN-NORMAL CHANCE OF OVERNIGHT THUNDERSTORMS. SHOWERS AND STORMS
ARE AGAIN FORECAST FOR WED AFTERNOON AND EVENING OVER ALL BUT
WESTERN HARNEY COUNTY. THERE WILL BE A MIN IN CONVECTION LATE WED
NIGHT THROUGH LATE MORNING THU. BY THU AFTERNOON...THE MAIN
CHANCE OF THUNDERSTORMS MOVES BACK TO THE IDAHO SIDE AND NRN
BAKER COUNTY. TEMPS WILL REMAIN MUCH LIKE THEY HAVE BEEN OVER THE
PAST SEVERAL DAYS WHILE OVERNIGHT LOWS WILL REMAIN VERY CLOSE TO
NORMAL...AND A LITTLE LOWER THAN OVER THE WEEKEND. OVERALL...
CHANGES TO THE FORECAST WERE MINIMAL.

LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...AS THE CLOSED LOW
MOVES TO OUR EAST...PRECIP CHANCES RAPIDLY DROP OFF AS A RIDGE
BEGINS TO BUILD IN. A FEW ISOLATED SHOWERS IN THE IDAHO CENTRAL
MOUNTAINS MAY REMAIN IN THE AFTERNOONS...BUT OTHERWISE A WARMING
AND DRYING TREND IS EXPECTED THROUGH THE WEEKEND. SUNDAY LOOKS TO
BE THE WARMEST DAY WITH TEMPERATURES 10-15 DEGREES ABOVE NORMAL.
NEXT PACIFIC SYSTEM LOOKS TO ARRIVE EARLY NEXT WEEK WHICH WILL
DECREASE TEMPERATURES AND INCREASE RAIN CHANCES.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.

&&

WEATHER.GOV/BOISE

DISCUSSION...JS
AVIATION.....VM
PREV SHORT TERM...SP
PREV LONG TERM....EP/DD

The office that day

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

IssuedProductOfficeCountiesLasted
May 27, 2:21 PM MDTSpecial Weather StatementBOI24 min

Nearby

Severe Thunderstorm Warnings in Idaho, 2015Every severe thunderstorm warning in 2015

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.