Alert archive / Idaho / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 22, NWS Missoula, MT

July 20, 2001Idaho County, Idaho

NWS Missoula, MT issued this severe thunderstorm warning at Jul 20, 2001, 5:04 PM PDT for Idaho County, Idaho. It was in force for 41 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued
Jul 20, 2001, 5:04 PM PDT (00:04 UTC)
Expired
Jul 20, 2001, 5:45 PM PDT
In force
41 min
Issued by
NWS Missoula, MT
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Idaho County, ID

The nearest sounding before it

Spokane, WA (KOTX), launched 00:00Z, 0.1 hours before the alert went out and 189 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, Spokane, WA at 00:00Z on 2001-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 257 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 00:00Z on 2001-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 square meters per square second.19395878Sfc1 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
257 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
2144 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
17 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.

914 
WUUS55 KMSO 210004
SVRMSO
IDC049-210045-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MISSOULA MT
504 PM PDT FRI JUL 20 2001

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WESTERN IDAHO COUNTY IN CENTRAL IDAHO

* UNTIL 545 PM PDT(645 PM MDT)

* AT 504 PM PDT(604 PM MDT)...RADAR INDICATED A SEVERE THUNDERSTORM
  14 MILES WEST OF GRANGEVILLE...MOVING NORTHEAST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL BE...
  5 MILES NORTHWEST OF GRANGEVILLE AT 520 PM PDT
  4 MILES SOUTHEAST OF KOOSKIA AT 545 PM PDT

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS AND HAIL...ALONG WITH
FREQUENT LIGHTNING AND HEAVY RAIN. FOR YOUR PROTECTION...GO INDOORS
AND STAY AWAY FROM WINDOWS. IF YOU ARE CAUGHT OUTSIDE...MOVE TO A
WELL PROTECTED AREA.


LAT...LON 4594 11655 4579 11642 4607 11565 4628 11583

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 Missoula, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 20, 1:00 PM PDT, 4 hours 4 minutes earlier.

Area forecast discussion, Jul 20, 1:00 PM PDT, 4 hours 4 minutes before
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
200 PM MDT FRI JUL 20 2001

.SHORT TERM...WV SHOWS A LONG WAVE TROF OVER THE PACIFIC NORTHWEST
WITH NUMBER OF S/WS ROTATING AROUND WITH THE FLOW. OF PARTICULAR
INTEREST...IS A STRONG WAVE OVER CENTRAL OREGON WHICH IS PROGGED TO
LIFT NORTHEAST BY SATURDAY MORNING. MESO IS VERY CONSISTENT WITH
EARLIER RUNS THIS FEATURE. THIS AFTERNOONS CONVECTIVE ACTIVITY
WILL CARRY INTO THE OVERNIGHT PERIOD WITH NEGATIVE LIS UNTIL AFTER
MIDNIGHT. ADDITIONALLY..A FEW WEAK WAVES IN THE FLOW AND UPPER
DIFFLUENCE WILL SUPPORT THIS ACTIVITY. ON SATURDAY...THE TROF AXIS
REMAINS OVER EAST WASHINGTON AND OREGON WITH LIS OVER THE
FORECAST AREA BETWEEN -2 AND -4. ANOTHER ACTIVE NIGHT AS THE MAIN S/W
SHIFTS EAST. EARLY SUNDAY MORNING...THE UPPER FLOW SHIFTS WEST WITH
CYCLONIC CURVATURE REMAINING OVER THE NORTHWEST ZONES. WILL GO WITH
CHANCE POPS OVER THESE ZONES. SLIGHT CHANCE POPS FOR THE REST OF THE
CWA AS S/W RIDGING BUILDS DURING THE DAY. STOLL

.EXTENDED...NO REAL CHANGES TO FORECAST TREND. GRADUAL WARMING AND
DRYING WILL BE ADVERTISED OVER THE COURSE OF THE FORECAST PERIOD. THE
UPPER LEVEL TROUGH BEGINS TO FILL AS IT DRIFT EAST OVER THE NORTHERN
ROCKIES REGION DAY3/4 FOR CHANCE POPS. THEN MODELS SUGGEST THAT THE
UPPER FLOW BECOMES MORE ZONAL WITH RISING HEIGHTS FOR DECREASING
POPS DAY5. BY DAY6/7...MODELS DIVERGE WITH ECMWF7 SHOWING RIDGING AND
MRF INDICATING A TROUGH OVER THE REGION. WILL LEAN TOWARD WARM/DRIER
ECMWF SOLUTION. MSJ

.MSO...FLASH FLOOD WATCH FOR SOUTHERN RAVALLI COUNTY UNTIL MIDNIGHT.

In the hours before

Special weather statement, Jul 20, 12:30 PM PDT, 4 hours 34 minutes before
IDZ005>010-MTZ004>007-043-210600-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MISSOULA MT
130 PM MDT FRI JUL 20 2001

...STRONG THUNDERSTORMS WITH HEAVY RAIN AND HAIL POSSIBLE THIS
AFTERNOON AND TONIGHT...

DEVELOPING THUNDERSTORMS IN CENTRAL IDAHO THIS AFTERNOON AND
MORE ACTIVITY IN WEST CENTRAL MONTANA WILL LIKELY PRODUCE LOCAL
DOWNPOURS INTO THIS EVENING DUE TO HIGH ATMOSPHERIC MOISTURE
CONTENT. HAIL UP TO HALF AN INCH IN DIAMETER IS ALSO POSSIBLE WITH
THESE STORMS ALONG WITH WIND GUSTS TO 40 MPH AND FREQUENT LIGHTNING.

PEOPLE ACROSS CENTRAL IDAHO AND WEST CENTRAL MONTANA ARE URGED TO
TUNE IN TO LOCAL WEATHER INFORMATION SOURCES FOR THE LATEST
INFORMATION AND STATEMENTS ON THIS DEVELOPING WEATHER SITUATION.

THUNDERSTORMS ARE EXPECTED TO DIMINISH AFTER MIDNIGHT TONIGHT.
HOWEVER...MORE STRONG THUNDERSTORM ACTIVITY IS ANTICIPATED SATURDAY.

The office that day

Everything else NWS Missoula, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 20, 5:56 PM PDTSevere Thunderstorm WarningMSOClearwater, Idaho49 min

Nearby

Severe Thunderstorm Warnings in Idaho, 2001Every severe thunderstorm warning in 2001

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.