Alert archive / Montana / Flash Flood Watches in 2012

Flash Flood Watch 2, NWS Missoula, MT

July 16, 20129 counties in Montana; Clearwater County, Idaho County, Idaho

NWS Missoula, MT issued this flash flood watch at Jul 16, 2012, 3:04 PM MDT for 9 counties in Montana; Clearwater County, Idaho County, Idaho. It was in force for 5 hr.

The area

The counties it named.

The facts

Issued
Jul 16, 2012, 3:04 PM MDT (21:04 UTC)
Expired
Jul 16, 2012, 8:27 PM MDT
In force
5 hr
Issued by
NWS Missoula, MT
Flood severity
None

Counties Clearwater County, ID, Idaho County, ID, Deer Lodge 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), 43 km from the middle of the area, began a volume at 21:06 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, 9.1 hours before the alert went out and 206 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 12:00Z on 2012-07-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 136 joules per kilogram.LCLLFCEL10008507005003002001001 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 12:00Z on 2012-07-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 72 square meters per square second.193958Sfc1 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
136 J/kg
Mixed-layer CIN
-116 J/kg
Mixed-layer LCL
888 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
72 m²/s²
0-3 km storm-relative helicity
295 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

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

615 
WGUS65 KMSO 162104
FFAMSO

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH
NATIONAL WEATHER SERVICE MISSOULA MT
304 PM MDT MON JUL 16 2012

IDC035-049-MTC023-039-047-061-063-077-081-089-093-170515-
/O.NEW.KMSO.FF.A.0002.120716T2104Z-120717T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLEARWATER-IDAHO-DEER LODGE-GRANITE-LAKE-MINERAL-MISSOULA-POWELL-
RAVALLI-SANDERS-SILVER BOW-
304 PM MDT MON JUL 16 2012 /204 PM PDT MON JUL 16 2012/

...FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT MDT /11 PM PDT/
TONIGHT...

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A

* FLASH FLOOD WATCH FOR PORTIONS OF NORTH CENTRAL IDAHO AND 
  MONTANA...INCLUDING THE FOLLOWING COUNTIES...IN NORTH CENTRAL 
  IDAHO...CLEARWATER AND IDAHO. IN MONTANA...DEER LODGE... 
  GRANITE...LAKE...MINERAL...MISSOULA...POWELL...RAVALLI... 
  SANDERS AND SILVER BOW. 

* UNTIL MIDNIGHT MDT /11 PM PDT/ TONIGHT

* MONSOONAL MOISTURE CONTINUES TO STREAM INTO THE NORTHERN ROCKIES
  THIS AFTERNOON AND EVENING. SLOW MOVING SHOWERS AND
  THUNDERSTORMS HAVE DEVELOPED OVER THE REGION AND WILL MOVE
  NORTHWARD THIS EVENING. THESE STORMS WILL BE CAPABLE OF
  PRODUCING VERY HEAVY RAIN. RAINFALL RATES OVER AN INCH AN HOUR
  ARE POSSIBLE WITH THESE STORMS.

* THE HEAVY RAIN COULD CAUSE FLOODING...BUT ALSO ROCK AND MUD SLIDES
  IN THE HIGHER TERRAIN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$
1 follow-up statement
066 
WGUS65 KMSO 170227 AAA
FFAMSO

FLOOD WATCH...UPDATED
NATIONAL WEATHER SERVICE MISSOULA MT
827 PM MDT MON JUL 16 2012

IDC035-049-MTC023-039-047-061-063-077-081-089-093-170330-
/O.CAN.KMSO.FF.A.0002.000000T0000Z-120717T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLEARWATER-IDAHO-DEER LODGE-GRANITE-LAKE-MINERAL-MISSOULA-POWELL-
RAVALLI-SANDERS-SILVER BOW-
825 PM MDT MON JUL 16 2012 /725 PM PDT MON JUL 16 2012/

...FLASH FLOOD WATCH IS CANCELLED...

THE FLASH FLOOD WATCH FOR PORTIONS OF NORTH CENTRAL IDAHO AND
MONTANA HAS BEEN CANCELLED. 

SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TONIGHT AND
COULD BE HEAVY AT TIMES...BUT THE MAIN THREAT FOR FLASH FLOODING
HAS DIMINISHED.
 
$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 16, 2:42 PM MDTFlash Flood WarningMSOSilver Bow93 min
Jul 16, 3:08 PM MDTFlash Flood WarningMSOGranite, Ravalli112 min
Jul 16, 2:27 PM MDTSevere Thunderstorm WarningMSOIdaho33 min
Jul 16, 4:29 PM MDTSpecial Weather StatementMSOClearwater46 min

Nearby

Flash Flood Watches in Montana, 2012Flash Flood Watches in Idaho, 2012Every flash flood watch in 2012

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.