Alert archive / Idaho / Special Weather Statements in 2021
Special Weather Statement, NWS Boise, ID
NWS Boise, ID issued this special weather statement at Aug 4, 2021, 8:12 PM MDT for Boise County, Idaho. It was in force for 33 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
- Aug 4, 2021, 8:12 PM MDT (02:12 UTC)
- Expired
- Aug 4, 2021, 8:45 PM MDT
- In force
- 33 min
- Issued by
- NWS Boise, ID
- Hail
- 0.50 in
- Wind
- 40
County Boise County, ID
The radar
The Boise radar (KCBX), 43 km from the middle of the area, began a volume at 02:10 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, 2.2 hours before the alert went out and 34 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
- 1128 J/kg
- Mixed-layer CIN
- -13 J/kg
- Mixed-layer LCL
- 3663 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 26 m²/s²
- 0-3 km storm-relative helicity
- 54 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.6
The text
As transmitted.
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>What forecasters said that day
The local office's own words before this special weather statement 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 special weather statement went out at Aug 4, 2:25 PM MDT, 5 hours 47 minutes earlier.
Area forecast discussion, Aug 4, 2:25 PM MDT, 5 hours 47 minutes before
Area Forecast Discussion
National Weather Service Boise ID
225 PM MDT Wed Aug 4 2021
.SHORT TERM...Tonight through Friday night...Thunderstorms this
evening working with a very hot airmass, and relatively dry lower
levels, so wind gust threat remains high through the evening. Low
off the CA coast approaches the area for Thursday. Quite a bit of
clouds over the area in the morning according to most models,
which may inhibit storm development early Thursday. But, increased
moisture, shear, and instability should overcome that by late
afternoon, and several models have impressive looking
thunderstorms over the area Thursday evening, as a cold front
moves through from the west, and continuing into early Friday as
the low moves overhead. Some of these storms could be severe. By
Friday afternoon, most of the storms should move into eastern ID,
with some cooler, northwest winds over much of southwest ID and
eastern OR.
.LONG TERM...Saturday through Wednesday...Dry westerly flow aloft
south of an upper level low pressure trough will keep skies mostly
clear over the weekend. Any showers associated with the trough are
expected to reach no farther south than the west central Idaho
mountains. The pattern becomes more uncertain starting Monday, but
models agree that the trough will keep temperatures a few degrees
below normal through Tuesday. Wednesday could be warmer, as some of
the ensembles are showing the flow shifting into the southwest as an
upper level high pressure ridge strengthens over the central Rockies
and four corners.
&&
.AVIATION...Generally VFR. Isolated thunderstorms ending in most
areas by 06z, but continuing overnight in the central Idaho
mountains and Baker Co. Oregon. Widespread showers and isolated
thunderstorms on Thursday. Wildfire smoke layers aloft reducing
visibility. Surface winds: variable 10 kts or less, except gusts 40-
50 kts possible near thunderstorms. Winds aloft at 10k feet MSL:
southwest 10-20 kts.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning from noon Thursday to midnight MDT Thursday
night IDZ400>403.
OR...Red Flag Warning from noon MDT /11 AM PDT/ Thursday to midnight
MDT /11 PM PDT/ Thursday night ORZ636-637-646.
&&
www.weather.gov/Boise
www.facebook.com/NWSBoise
www.twitter.com/NWSBoise
SHORT TERM...TB
LONG TERM....JT
AVIATION.....JTIn the hours before
Special weather statement, Aug 4, 7:49 PM MDT, 23 minutes before
Special Weather Statement
National Weather Service Boise ID
749 PM MDT Wed Aug 4 2021
IDZ012-033-ORZ064-050215-
Lower Treasure Valley ID-Upper Weiser River ID-
Oregon Lower Treasure Valley OR-
749 PM MDT Wed Aug 4 2021
...A strong thunderstorm will impact portions of Payette,
northwestern Gem, south central Washington and northeastern Malheur
Counties through 815 PM MDT...
At 748 PM MDT, Doppler radar was tracking a strong thunderstorm near
Fruitland, or near Payette, moving northeast at 35 mph.
HAZARD...Winds in excess of 30 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
This strong thunderstorm will be near...
Bear Creek Summit, French Corner and Paddock Valley Reservoir
around 810 PM MDT.
LAT...LON 4392 11689 4407 11703 4435 11658 4413 11636
TIME...MOT...LOC 0148Z 235DEG 31KT 4404 11687
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...30 MPH
LCSpecial weather statement, Aug 4, 8:12 PM MDT, 0 minutes before
Special Weather Statement
National Weather Service Boise ID
812 PM MDT Wed Aug 4 2021
IDZ012-013-050245-
Lower Treasure Valley ID-Boise Mountains ID-
812 PM MDT Wed Aug 4 2021
...A strong thunderstorm will impact portions of west central Boise
and southeastern Gem Counties through 845 PM MDT...
At 811 PM MDT, Doppler radar was tracking a strong thunderstorm near
Horseshoe Bend, or 16 miles east of Emmett, moving northeast at 20
mph.
HAZARD...Winds in excess of 40 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
This strong thunderstorm will be near...
Gardena around 830 PM MDT.
Idaho City, Centerville, Pioneerville and Harris Creek Summit
around 840 PM MDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4373 11617 4387 11634 4412 11603 4387 11572
TIME...MOT...LOC 0211Z 234DEG 17KT 4384 11617
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH
SHThe office that day
Everything else NWS Boise, ID issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 4, 7:49 PM MDT | Special Weather Statement | BOI | Payette | 26 min |
| Aug 4, 8:29 PM MDT | Special Weather Statement | BOI | Gem | 31 min |
| Aug 4, 8:48 PM MDT | Special Weather Statement | BOI | Boise | 27 min |
| Aug 4, 9:05 PM MDT | Special Weather Statement | BOI | Ada | 25 min |
| Aug 5, 2:41 AM MDT | Wind Advisory | BOI | Ada, Adams, Camas, Canyon, Elmore, Gem and 6 more | 27 hr |
| Aug 4, 9:18 PM MDT | Special Weather Statement | BOI | Baker | 27 min |
| Aug 5, 5:35 PM MDT | Special Weather Statement | BOI | Baker | 25 min |
Nearby
Special Weather Statements in Idaho, 2021Every special weather statement in 2021
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.