Alert archive / Oregon / Mesoscale Discussions in 2024
Mesoscale Discussion 430
The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2024, 11:53 AM PDT for 4 states. It was in force for 97 min.
The area
The outline as issued.
The facts
- Issued
- Apr 12, 2024, 11:53 AM PDT (18:53 UTC)
- Expired
- Apr 12, 2024, 1:30 PM PDT
- In force
- 97 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Lassen County, CA, Modoc County, CA, Plumas County, CA, Adams County, ID, Canyon County, ID, Gem County, ID, Payette County, ID, Washington County, ID, Humboldt County, NV, Washoe County, NV, Baker County, OR, Crook County, OR, Deschutes County, OR, Grant County, OR, Harney County, OR, Klamath County, OR, Lake County, OR, Malheur County, OR, Union County, OR, Wallowa County, OR
The nearest sounding before it
Boise Airport, ID (KBOI), launched 12:00Z, 6.9 hours before the alert went out and 274 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
- 2565 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- -34 m²/s²
- 0-3 km storm-relative helicity
- 32 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
646
ACUS11 KWNS 121854
SWOMCD
SPC MCD 121853
IDZ000-ORZ000-NVZ000-CAZ000-122030-
Mesoscale Discussion 0430
NWS Storm Prediction Center Norman OK
0153 PM CDT Fri Apr 12 2024
Areas affected...Northeast California...Eastern Oregon...far Western
Idaho...and northwest Nevada
Concerning...Severe potential...Watch unlikely
Valid 121853Z - 122030Z
Probability of Watch Issuance...20 percent
SUMMARY...A few strong to occasionally severe storms are possible
this afternoon from northeast California into eastern Oregon and
western Idaho.
DISCUSSION...Thunderstorms have developed amid weak instability
across the higher terrain in northeast California. Additional
development is apparent on visible satellite along a differential
heating boundary along the edge of the mid-level cloud deck across
portions of eastern Oregon. Instability remains quite weak at this
time with temperatures only in the 60s. However, temperatures are
expected to warm into the upper 60s to low 70s with MLCAPE around
250 to 500 J/kg by later this afternoon. This, combined with around
25 to 30 knots of effective shear, should be sufficient for some
organized storms this afternoon. Forecast soundings show very deep
mixing (to near 500mb) which will support some severe wind threat.
The hail threat will be mostly across eastern Oregon and western
Idaho where greater instability and somewhat stronger shear are
expected later this afternoon. Given the expectation for isolated
coverage of severe storms, no watch is anticipated.
..Bentley/Goss.. 04/12/2024
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MSO...BOI...LKN...PDT...REV...MFR...STO...
LAT...LON 39742155 41572219 43892133 45701760 45631615 44971581
42901648 41081785 40051915 39711995 39742155SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 12, 2:42 PM PDT | Mesoscale Discussion | SPC | Ada, Blaine, Boise, Butte, Camas, Clark and 9 more | 2 hr |
Nearby
Mesoscale Discussions in Oregon, 2024Mesoscale Discussions in Idaho, 2024Mesoscale Discussions in California, 2024Every mesoscale discussion in 2024
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.