Alert archive / Oregon / Mesoscale Discussions in 2008
Mesoscale Discussion 2467
The Storm Prediction Center issued this mesoscale discussion at Dec 14, 2008, 3:46 AM PST for 11 counties in Oregon; Clark County, Washington. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 14, 2008, 3:46 AM PST (11:46 UTC)
- Expired
- Dec 14, 2008, 8:15 AM PST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
Counties Benton County, OR, Clackamas County, OR, Columbia County, OR, Douglas County, OR, Lane County, OR, Linn County, OR, Marion County, OR, Multnomah County, OR, Polk County, OR, Washington County, OR, Yamhill County, OR, Clark County, WA
The radar
The Portland,OR radar (KRTX), 118 km from the middle of the area, began a volume at 12:04 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
Salem/Mcnary, OR (KSLE), launched 00:00Z, 11.8 hours before the alert went out and 30 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
- 642 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 117 m²/s²
- 0-3 km storm-relative helicity
- 172 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000
ACUS11 KWNS 141146
SWOMCD
SPC MCD 141146
WAZ000-ORZ000-141615-
MESOSCALE DISCUSSION 2467
NWS STORM PREDICTION CENTER NORMAN OK
0546 AM CST SUN DEC 14 2008
AREAS AFFECTED...LOWER ELEVATIONS OF WRN OR/SWRN WA
CONCERNING...HEAVY SNOW
VALID 141146Z - 141615Z
CONVECTIVE SNOW SHOWERS WITH LOCALIZED RATES BETWEEN 1 TO 2 INCHES
PER HOUR ARE EXPECTED IN THE WILLAMETTE VALLEY AND SWRN WA THIS
MORNING.
LATEST SURFACE ANALYSIS SHOWS SURFACE LOW COUPLET OVER THE PACIFIC
NORTHWEST WITH ONE LOW CENTER JUST SW OF QUILLAYUTE AND A SECOND
CENTER JUST EAST OF BEND. MODIFIED ARCTIC BNDRY IS NOW JUST WEST OF
A PORTLAND TO BEND LINE...AND WILL CONTINUE TO MOVE SWD DURING THE
MORNING HOURS. TEMPERATURES WILL FALL TO NEAR OR BELOW FREEZING AS
CONVECTIVE SHOWERS OVERSPREAD COLD AIR ADVECTION SEEPING THROUGH THE
COLUMBIA GORGE. COLDEST CONVECTIVE CLOUD TOPS ON IR CONTINUE TO
IMPINGE ON THE COASTAL MOUNTAINS...AND WILL LIKELY INCREASE IN
COVERAGE/INTENSITY BETWEEN 14 AND 18 UTC. THE 06 UTC HIGH-RESOLUTION
WRF RUNS SUPPORT THIS SCENARIO...WITH LOCALIZED EXPLICIT
PRECIPITATION RATES EXCEEDING 0.25 INCH /LIQUID EQUIVALENT/ PER HOUR
IN THE STRONGER CELLS. GIVEN THE COLD AIR SEEPAGE INTO NRN/CNTRL
WILLAMETTE VALLEY...AS SURFACE TEMPERATURES APPROACH AND FALL BELOW
FREEZING IN THE PORTLAND METRO AREA/SALEM/EUGENE...ACCUMULATING
SNOWFALL RATES BETWEEN 1 TO 2 INCHES PER HOUR WILL ACCOMPANY
LOCALIZED HEAVIER SHOWERS. ELEVATED/WINDWARD SLOPES ALONG THE
COASTAL AND CASCADE MOUNTAINS WILL EASILY MEET/EXCEED THESE SNOWFALL
RATES.
..BRIGHT.. 12/14/2008
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
...NOTICE...
SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A
SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR
TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC
FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS.
ATTN...WFO...MFR...PQR...
LAT...LON 44782383 45602371 45842370 45972358 46052307 45872242
45612221 45312210 44742212 44172218 43782230 43502237
43262277 43292330 43392368 43562396 44252390 44782383Nearby
Mesoscale Discussions in Oregon, 2008Mesoscale Discussions in Washington, 2008Every mesoscale discussion in 2008
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.