Alert archive / Utah / Mesoscale Discussions in 2007
Mesoscale Discussion 2249
The Storm Prediction Center issued this mesoscale discussion at Dec 20, 2007, 4:34 PM MST for 8 counties in Utah. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 20, 2007, 4:34 PM MST (23:34 UTC)
- Expired
- Dec 20, 2007, 9:30 PM MST
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
Counties Beaver County, UT, Iron County, UT, Morgan County, UT, Piute County, UT, Sanpete County, UT, Sevier County, UT, Summit County, UT, Wasatch County, UT
The radar
The Salt Lake City radar (KMTX), 199 km from the middle of the area, began a volume at 23:37 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
Salt Lake City I, UT (KSLC), launched 12:00Z, 11.6 hours before the alert went out and 141 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
- 1275 m above ground
- 0-6 km bulk shear
- 65 kt
- 0-1 km storm-relative helicity
- 172 m²/s²
- 0-3 km storm-relative helicity
- 240 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 202335 SWOMCD SPC MCD 202334 UTZ000-WYZ000-210430- MESOSCALE DISCUSSION 2249 NWS STORM PREDICTION CENTER NORMAN OK 0534 PM CST THU DEC 20 2007 AREAS AFFECTED...CENTRAL UT CONCERNING...HEAVY SNOW VALID 202334Z - 210430Z HEAVY SNOW IS EXPECTED TO INCREASE WITH QUICKLY LOWERING SNOW LEVELS THIS EVENING ACROSS MUCH OF CENTRAL UT FROM THE WASATCH/WESTERN UINTA MOUNTAINS TO THE SOUTH CENTRAL MOUNTAINS...INCLUDING AREAS ALONG/EAST OF THE I-15 CORRIDOR. SNOW RATES OF 2+ IN/HR WILL BECOME INCREASINGLY LIKELY ESPECIALLY IN THE HIGHER ELEVATIONS/MOUNTAINS. WATER VAPOR IMAGERY FEATURES POTENT/VERY COLD UPPER TROUGH TRANSITIONING EAST-SOUTHEASTWARD ACROSS THE GREAT BASIN...WITH A STRONG COLD FRONT CROSSING NORTHERN UT /SALT LAKE VICINITY/ AND EASTERN/SOUTH CENTRAL NV AS OF 23Z. INCREASING LARGE SCALE FORCING FOR ASCENT AND ENHANCED OROGRAPHIC LIFT /ESPECIALLY SOUTHWEST FACING SLOPES/ VIA STRONG SOUTHWEST MID LEVEL FLOW /60-80 KT AT 500 MB/ WILL FAVOR MODERATE/HEAVY SNOW THIS EVENING. WITH THE PASSAGE OF THE COLD FRONT ACROSS UT TONIGHT...SNOW LEVELS WILL QUICKLY LOWER GIVEN THE ARRIVAL OF COLDER AIR ALOFT /-28C AT 500 MB PER UPSTREAM 18Z RENO NV RAOB/. OF NOTE...SCATTERED CLOUD-GROUND LIGHTNING HAS BECOME INCREASINGLY COMMON OVER THE PAST SEVERAL HOURS FROM EAST CENTRAL NV INTO NORTHERN UT/SALT LAKE VICINITY IN ASSOCIATION WITH THE COLD FRONT. ACCORDINGLY...A ROUGHLY 3-6 HR PERIOD OF HEAVY CONVECTIVE SNOW/POSSIBLE THUNDERSNOW APPEARS LIKELY WITH THE PASSAGE OF THE COLD FRONT VIA STRONG LINEAR FORCING/INCREASING OROGRAPHIC LIFT AND MODEST SLANTWISE/UPRIGHT INSTABILITY...WITH 2+ IN/HR SNOW RATES LIKELY THIS EVENING ESPECIALLY IN THE MOUNTAINS. ..GUYER.. 12/20/2007 ...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...SLC... 41431157 41121100 40501058 40191097 39611116 38681164 38251190 37701284 37641324 37941339 38271337 38871260 39231208 39771176 40231161 40881178
Nearby
Mesoscale Discussions in Utah, 2007Every mesoscale discussion in 2007
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.