Alert archive / Oregon / Mesoscale Discussions in 2015
Mesoscale Discussion 2004
The Storm Prediction Center issued this mesoscale discussion at Dec 1, 2015, 7:14 PM PST for Gilliam County, Hood River County, Sherman County, Oregon; Klickitat County, Washington. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 1, 2015, 7:14 PM PST (03:14 UTC)
- Expired
- Dec 2, 2015, 1:15 AM PST
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
Counties Gilliam County, OR, Hood River County, OR, Sherman County, OR, Klickitat County, WA
The radar
The Pendleton radar (KPDT), 158 km from the middle of the area, began a volume at 03:13 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, 3.2 hours before the alert went out and 185 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
- 1238 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 186 m²/s²
- 0-3 km storm-relative helicity
- 220 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
765
ACUS11 KWNS 020315
SWOMCD
SPC MCD 020314
WAZ000-ORZ000-020915-
MESOSCALE DISCUSSION 2004
NWS STORM PREDICTION CENTER NORMAN OK
0914 PM CST TUE DEC 01 2015
AREAS AFFECTED...PORTIONS OF THE COLUMBIA RIVER BASIN OF NRN ORE AND
SRN WA
CONCERNING...FREEZING RAIN
VALID 020314Z - 020915Z
SUMMARY...INITIAL SNOW/SLEET SHOULD TRANSITION TO MAINLY FREEZING
RAIN OVER THE NEXT FEW HOURS AS PRECIPITATION MOVES IN FROM THE
WEST. FREEZING-RAIN RATES WILL LIKELY EXCEED 0.05 INCH PER 3
HOURS...WITH RATES UP TO 0.1 INCH PER HOUR POSSIBLE THROUGH 09Z.
DISCUSSION...THE SFC GRADIENT BETWEEN AN AREA OF COLD HIGH PRESSURE
ACROSS THE NRN GREAT BASIN/ROCKIES AND LOWER PRESSURE OVER THE ERN
PACIFIC HAS ENCOURAGED ELY WINDS THROUGH THE COLUMBIA RIVER BASIN
TODAY. SFC TEMPERATURES THROUGH MOST OF THE BASIN REMAIN AOB
FREEZING AS OF 03Z...AND PRECIPITATION SHIFTING EWD FROM THE COAST
ASSOCIATED WITH A SHORTWAVE TROUGH SHOULD SPREAD OVER THE MCD AREA
IN THE NEXT FEW HOURS. RECENT AMDAR SOUNDINGS IN THE VICINITY OF
KPDX SHOW A PROMINENT WARM NOSE OF +6-9 DEG C CENTERED AROUND
925-900 MB. HOWEVER...FORECAST SOUNDINGS FROM THE LATEST NAM/HRRR
SUGGEST THIS WARM LAYER DOES NOT EXTEND MUCH FURTHER E THAN KPDX.
THEREFORE...PRECIPITATION ACROSS THE LOWER ELEVATIONS OF THE
COLUMBIA RIVER BASIN MAY INITIALLY BEGIN AS SNOW/SLEET...BEFORE
TRANSITIONING TO FREEZING RAIN AS SWLY WARM AIR ADVECTION OCCURS
MAINLY IN THE 850-700-MB LAYER. FREEZING-RAIN RATES WILL LIKELY
EXCEED 0.05 INCH PER 3 HOURS...AND RATES UP TO 0.1 INCH PER HOUR MAY
BE POSSIBLE.
..GLEASON.. 12/02/2015
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...PDT...PQR...
LAT...LON 45841967 45571968 45371999 45282081 45282176 45342224
45542232 45842223 45922175 46032062 46011983 45841967Nearby
Mesoscale Discussions in Oregon, 2015Mesoscale Discussions in Washington, 2015Every mesoscale discussion in 2015
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.