Alert archive / Montana / Heavy Snow Warnings in 2007
Heavy Snow Warning 15, NWS Missoula, MT
NWS Missoula, MT issued this heavy snow warning at Nov 18, 2007, 2:59 PM MST for 10 counties in Montana; Clearwater County, Idaho County, Idaho. It took effect at Nov 18, 2007, 5:00 PM MST. It was in force for 21 hr. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Nov 18, 2007, 2:59 PM MST (21:59 UTC)
- In effect from
- Nov 18, 2007, 5:00 PM MST
- Expired
- Nov 19, 2007, 2:13 PM MST
- In force
- 21 hr
- Issued by
- NWS Missoula, MT
Counties Clearwater County, ID, Idaho County, ID, Deer Lodge County, MT, Flathead County, MT, Granite County, MT, Lake County, MT, Mineral County, MT, Missoula County, MT, Powell County, MT, Ravalli County, MT, Sanders County, MT, Silver Bow County, MT
The radar
The Missoula radar (KMSX), 29 km from the middle of the area, began a volume at 22:01 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
Spokane, WA (KOTX), launched 12:00Z, 10.0 hours before the alert went out and 198 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1734 m above ground
- 0-6 km bulk shear
- 75 kt
- 0-1 km storm-relative helicity
- -12 m²/s²
- 0-3 km storm-relative helicity
- 17 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this heavy snow 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 heavy snow warning went out at Nov 18, 9:35 AM MST, 5 hours 24 minutes earlier.
Area forecast discussion, Nov 18, 9:35 AM MST, 5 hours 24 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
935 AM MST SUN NOV 18 2007
.UPDATE...WILL DECREASE MAX TEMPERATURES IN PARTS OF SOUTHWEST
MONTANA AND EAST CENTRAL IDAHO FOR TODAY.
&&
.AVIATION...THE MOIST PATTERN WILL MAINTAIN WIDESPREAD TERRAIN
OBSCURATIONS AS WELL AS AREAS OF LOWERED CEILINGS AND REDUCED
VISIBILITIES. WINDS WILL REMAIN STRONG FROM THE WEST ALOFT. LESS
WIND SHEAR IS EXPECTED EARLY TODAY WITH THE SURFACE GRADIENT ALSO
WESTERLY. HOWEVER...AS THE FRONT DEVELOPS THIS AFTERNOON ACROSS
NORTH CENTRAL IDAHO AND WEST CENTRAL MONTANA...SURFACE WINDS WILL BE
MORE CHAOTIC LENDING TO INCREASED SHEAR IN THE LOW LEVELS.
&&
.PREV DISCUSSION... /ISSUED 323 AM MST SUN NOV 18 2007/
DISCUSSION...A WESTERLY JET ALOFT AND A DEVELOPING COLD FRONT AT
THE SURFACE WILL CONTINUE THE WET PATTERN OVER THE NORTHERN
ROCKIES TODAY THROUGH MONDAY. RAIN AND HIGH MOUNTAIN SNOW WILL
BECOME WIDESPREAD TODAY OVER NORTH CENTRAL IDAHO AND WEST CENTRAL
MONTANA...THEN SLOWLY SPREAD NORTH OVERNIGHT. SNOW LEVELS WILL
BEGIN TO FALL NORTH OF THE FRONT...BUT REMAIN FAIRLY HIGH ACROSS
SOUTHWEST MONTANA AND LEMHI COUNTY IDAHO. IN THE COOLER AIR...SNOW
ACCUMULATIONS OF 8 TO 16 INCHES ARE POSSIBLE IN THE MOUNTAINS
ABOVE 5000 FEET...AND THE POTENTIAL FOR 3 TO 6 INCHES DOWN TO 4000
FEET FROM THIS EVENING THROUGH MONDAY AFTERNOON. BREEZY WEST WINDS
COULD CAUSE SOME BLOWING AND DRIFTING OF THE SNOW AS WELL.
THE JET AND FRONT WILL SAG SOUTH MONDAY AFTERNOON...ALLOWING THE
STEADY PRECIPITATION TO BECOME MORE SHOWERY AND SLOWLY TAPER FROM
THE NORTH.
COOLER AIR WILL ADVECT IN OVER MUCH OF THE NORTHERN ROCKIES SLOWLY
TODAY...THEN IN MORE ERNEST MONDAY. THEREFORE...HIGHS TODAY WILL
LIKELY REMAIN STEADY OR FALL SLIGHTLY THROUGH THE DAY AND THEN BE
NOTICEABLY COOLER MONDAY.
A RIDGE OF HIGH PRESSURE IS EXPECTED TO BUILD OFF THE PACIFIC
COAST TUESDAY...BRINGING A DRIER AND COOLER NORTHERLY FLOW TO THE
NORTHERN ROCKIES. TEMPERATURES ARE EXPECTED TO COOL TO SLIGHTLY BELOW
NORMAL FOR THIS TIME OF THE YEAR WITH MANY VALLEY LOCATIONS
STRUGGLING TO WARM ABOVE FREEZING BY WEDNESDAY. WITH COMBINATION
OF CLEARING SKIES AND REMNANT SURFACE MOISTURE FROM PRECIPITATION
THIS WEEKEND...EXPECT TO SEE FREEZING FOG FORM IN FAVORED VALLEY
LOCATIONS EACH MORNING THROUGH FRIDAY.
FORECAST BECOMES A LITTLE MORE UNCERTAIN BEYOND FRIDAY AS FORECAST
MODELS VARY ON THE STRENGTH AND POSITION OF THE PREVIOUSLY
MENTIONED RIDGE. IN EITHER CASE...SEEMS THAT COOL TEMPERATURES
WILL PERSIST WITH THE POSSIBILITY OF WEAK WEATHER DISTURBANCES
BRUSHING THE REGION.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WATCH FROM 5 PM MST THIS AFTERNOON THROUGH MONDAY
AFTERNOON FOR BITTERROOT/SAPPHIRE MOUNTAINS-LOWER CLARK
FORK REGION-POTOMAC/SEELEY LAKE REGION-WEST GLACIER REGION.
ID...WINTER STORM WATCH FROM 4 PM PST THIS AFTERNOON THROUGH MONDAY
AFTERNOON FOR NORTHERN CLEARWATER MOUNTAINS-SOUTHERN
CLEARWATER MOUNTAINS.
&&
SHORT TERM...RPN
LONG TERM....RPN
AVIATION...RPNThe office that day
Everything else NWS Missoula, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 18, 2:59 PM MST | Winter Storm Warning | MSO | Deer Lodge, Granite, Missoula, Powell, Ravalli, Silver Bow | 13 hr |
| Nov 17, 8:53 PM MST | Wind Advisory | MSO | Clearwater, Idaho | 82 min |
Nearby
Heavy Snow Warnings in Montana, 2007Heavy Snow Warnings in Idaho, 2007Every heavy snow warning in 2007
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.