Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
618 FXUS65 KSLC 301016 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 416 AM MDT Tue Apr 30 2024 .SYNOPSIS...A stalled front will remain draped across central Utah today, separating a cooler and more stable airmass across northern Utah from a warmer airmass across the south. A secondary cold front will cross the region tonight, bringing additional cooling for Wednesday. && .SHORT TERM (Through 12Z/6AM Thursday)...A shortwave trough exiting the region as it crosses the central Rockies is leaving a predominantly zonal flow in its wake across the Great Basin/Colorado Plateau region. The associated surface front currently bisects the forecast area as it stalls roughly along a Cedar City to Green River line. This boundary will slowly mix northward into central Utah today, separating a cooler and more stable airmass across northern Utah from a more mild and well mixed airmass to the south. Max temperatures across the northern valleys will trend roughly 10F cooler, ranging from the mid 50s in the Cache Valley to low 60s along the central and southern Wasatch Front. To the south of the boundary, temperatures across southern Utah will trend a degree or two warmer, reaching the low 70s around Cedar City, and low to mid 80s around St George, Zion Canyon and Bullfrog. The next shortwave trough will brush the northern Great Basin late tonight through Wednesday, pushing a re-enforcing surge of cold air into the region. Precip chances with this wave and along the associated frontal boundary are minimal...generally 20-30% along the higher terrain. The secondary surge of cold air will knock another 5F or so off high temperatures areawide Wednesday, with highs only reaching the low to mid 50s across the northern valleys. Depending on cloud cover Wednesday night, some outlying areas along the Wasatch Front such as near Tremonton/Brigham City as well as southern Utah Valley may dip to near freezing. .LONG TERM (After 12Z/6AM Thursday)...Southwest Wyoming and northern Utah will get more shortwave energy through later in the week. Isolated to scattered showers, primarily mountain snow showers are likely. Ensembles are in general agreement on a longwave trough pushing in during the weekend or near the start of the week. Thursday morning will likely be the coldest of the week, as a shortwave trough will be exiting with clearing conditions. Low temperatures will generally be above freezing for valleys of the urban corridor, but below freezing temperatures are likely for the Cache Valley, portions of eastern Box Elder County, and around Cedar City. Another shortwave trough will track into southwest Wyoming and northern Utah into Friday. Isolated to scattered valley rain and mountain snow showers are forecasted, with any rainfall or snowfall totals light. As the main trough lifts into Canada, the baroclinic zone will likely not track into southern Utah. Roughly 75% of ensemble members have the baroclinic zone reaching as far south as roughly Beaver, Piute, and Wayne counties. From the southern extent of the cold front, northward to the Idaho border, temperatures will be 5-10F warmer than normal. South of the cold front, temperatures will be 5-10F warmer than normal. There is good confidence that shortwave ridging will build into Utah Friday into Saturday, with a warm and dry Saturday. A longwave trough will be digging to the west Saturday. Uncertainty gets higher with details for the end of the weekend. Roughly 65% of ensemble members have the trough digging into Utah, where valley rain and mountain snow would be likely, while roughly 35% of members have it far enough to the west for dry conditions and gusty winds. Once the storm system pushes into Utah, measurable valley rainfall is likely with accumulating mountain snowfall. && .AVIATION...KSLC...Light northwest winds will prevail through the day. Clear skies will transition to scattered afternoon cloud cover. Clouds will increase into the evening as a rather dry cold front pushes in from the northwest. Winds will likely transition to southeast around 03Z, but switch to northwest once the front tracks through around 06-08Z. .REST OF UTAH AND SOUTHWEST WYOMING...Clear skies with relatively light winds will last through the morning. Clouds will increase for southwest Wyoming and northern Utah during the afternoon and evening with gusty southwest winds in southwest Wyoming. Clear skies will last through the day in southern Utah with gusty southwest winds most of the afternoon. A relatively dry cold front will track into northern Utah around 03Z, transitioning winds to northwest as it tracks south.&& .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Seaman/Wilson For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity