textproduct: Salt Lake City

KEY MESSAGES

- Another round of freezing overnight temperatures is expected tonight across eastern Box Elder county and portions of central and southwest UT.

- High pressure continues to build over the area with potentially record-breaking temperatures expected Monday and Tuesday.

- On Wednesday, the pattern looks to become wet and active again into the weekend and potentially early next week.

DISCUSSION

Current observations and satellite imagery are indicative of a cool northwesterly flow persisting over much of the forecast area as a ridge of high pressure builds in over much of the western U.S.. As geopotential heights continue to slowly rise with northwest flow persisting, temperatures today are expected to remain near normal for much of the region. With clear skies expected across portions of southern, central, and perhaps northwest UT, radiational cooling will set the stage for another night of slightly below normal low temperatures below freezing. Areas such as the I-15 corridor in eastern Box Elder county, western Uinta Basin, Castle Country, San Rafael Swell, Western Canyonlands, Southwest Utah, Western Millard and Juab counties, and southernmost Utah county can expect temperatures below freezing for a few hours tonight into tomorrow morning. As such, a freeze warning will be issued for these areas.

Another night of colder temperatures is expected Sunday evening into Monday evening, though confidence in below freezing temperatures across our active Ag zones appears less likely at this time. As we head into Monday afternoon, notable whiplash with our temperatures will occur as a substantial warm-up is expected to occur as geopotential heights increase aloft with ridging sliding east across the region. While our typical hot spot of lower Washington county can expect temperatures around 10F above normal, the most notable departure from our climatological normals will be across northern and central UT valleys where temperatures will range from 15-20F above normal. In fact, probabilities for daytime highs exceeding 80F along I-15 from Ogden to Santaquin range from 60-80% Monday afternoon with probabilities increasing to roughly 70-90%+ Tuesday afternoon along the same corridor.

On Tuesday afternoon, winds will increase along the western half of UT as an H5 trough begins to deepen as it traverses the Great Basin. On Wednesday, a cold front associated with this trough will traverse the region serving to increase precipitation chances across primarily northern UT with ample valley rainfall and some higher elevation snowfall expected. Additionally, the cold front will serve to bring temperatures back to around climatological normals across northern and central UT through at least Friday and shift the gusty wind threat to the eastern half of the state Wednesday afternoon. Some discrepancies exist with the timing of this front, resulting in a somewhat conditional strong to severe wind gust threat from storms ahead of the cold front Wednesday afternoon. The uncertainty is mainly due to preceding cloud cover which would inhibit surface mixing, greatly limiting DCAPE and instability as a whole. If the front is delayed somewhat, stronger mixing will be favored as background flow remains elevated thus raising DCAPE across the board. Effective shear ranging from around 30-40kts would support storms sustaining themselves if they were to form in a more primed environment with a delayed frontal passage, and this will be monitored over the coming days.

Into the late week and the weekend, ensemble guidance continues to support the active pattern persisting with nearly all ensemble clusters supportive of western U.S. troughing through the weekend. Some caveats exist, particularly with the strength of ridging across the eastern U.S. which would impact the placement of the trough (i.e. 40% of ensemble clusters support higher geopotential heights across the central U.S. keeping our forecast area within a diffluent flow regime ahead of an incoming trough favoring the unstable pattern vs the other 60% putting us on the colder side of the incoming systems). As such, the pattern looks to remain active, but not without some question marks going forward.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions are expected to persist across all of our TAF sites through the period. Diurnal winds are expected to persist across all of our TAF sites with KCDC seeing gusts up to 20kts tomorrow afternoon.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Freeze Warning from 10 PM this evening to 10 AM MDT Sunday for UTZ103-106-114>116-118>122-130.

WY...None.