textproduct: North Platte

KEY MESSAGES

- Dense fog persists this morning for much of southwest and central Nebraska, along with some threat for drizzle or freezing drizzle near and east of HWY 83 and south of HWY 2.

- Another round of fog develops tonight, with a threat for dense fog for much of southwest into central and north central Nebraska.

- Warmer temperatures prevail into the weekend, with fire concerns increasing due to mild, dry, and breezy conditions.

- A stronger cold front arrives on Monday, bringing a threat for rain and snow. This also brings a return of average temperatures (30s to low 40s) into next week.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 401 AM CST Thu Dec 26 2024

Currently, dense fog persists across much of southwest and central Nebraska, within a broad warm advection regime on the western periphery of surface high pressure and a surface trough across western Nebraska. It is near and ahead of this surface trough where dense fog persists, though thus far limited drizzle development has occurred. Temperatures are hovering at our just above freezing, and this has kept the threat for icing limited as well. Will maintain the inherited Winter Weather Advisory for now, though confidence is slowly waining in any impacts from freezing drizzle this morning.

As we head through this morning, southerly flow strengthens again with the area remaining positioned within a constricted surface pressure gradient. This is driven by continued lee cyclogenesis across eastern WY/CO and surface high pressure over the Great Lakes. Much like yesterday morning, the increasing southerly flow should erode lingering fog as well as boost highs back into the middle to upper 40s. Any slick roads this morning also look to rapidly improve by late morning.

By tonight, a northern stream trough will eject across the Rockies and into the Plains by early Friday morning. An associated surface low will eject eastward across South Dakota, dragging a cool front through the area overnight. Ahead of the boundary, weak southerly flow will again lead to a threat of fog across much of southwest into central and north central Nebraska Friday morning. Guidance has begun to hint at another round of dense fog, and Dense Fog Advisories may be needed yet again. The approach and passage of the surface frontal boundary may lead to a round of light precipitation, but confidence in this continues to wane. This is largely tied to increasing low level dry air, and rather meager forcing (tied to the upper low deepening further east over the upper Midwest). As the surface front clears the area by late morning, westerly downslope flow establishes and finally shunts the surface moisture off to the east of the area. This does two things, boosts highs back into well above average into the upper 40s/low 50s, and finally ends the near nightly threat for dense fog development.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Issued at 401 AM CST Thu Dec 26 2024

As we head into the weekend, upper ridging briefly establishes across the western CONUS, keeping conditions dry and highs well above average locally. With near daily breezy conditions, some increasing threat for fire weather conditions looks to develop across much of western and north central Nebraska.

By Sunday evening, troughing will begin to establish across the Pacific Northwest, flattening out the aforementioned upper ridging. This trough will begin to eject eastward across the northern Rockies into Monday morning, crossing into the Plains during the afternoon. As this occurs, deepening surface low pressure ejects across southwest Nebraska and northwest Kansas, with a strong surface cold front moving through the area Monday morning. This front will bring a couple of threats to the area, one of which being a threat for accumulating snow. This is tied to strong mid-level cold advection just behind the H7 low, strengthening FGEN, and quickly translating across northern Nebraska Monday afternoon. Guidance continues to paint the greatest threat for this quick round of accumulating snow to occur near and north of HWY 2 Monday afternoon. In fact, ensemble probabilities of >1" of snow continue to increase, and are even exceeding 70% near the HWY 20 corridor. Strong pressure rises and increasing cold advection with frontal passage will also bring quickly increasing northwest winds, with guidance already pointing towards a period of gusts exceeding 40mph across much of western and north central Nebraska. The greatest signal exists for southwest Nebraska at this time, where the ECMWF EFI has begun to show an SOT > 0 and a growing percentage of ensemble members suggesting strong wind gusts. It is here where gusts may approach/exceed 50 miles per hour from the northwest on Monday. A much colder airmass settles into the central CONUS into midweek and this brings a return of near average highs in the 30s.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 525 AM CST Thu Dec 26 2024

Low stratus and dense fog will persist through late this morning for much of western and north central Nebraska, with LIFR conditions continuing. Conditions improve this afternoon, with terminals northwest of an MCK to BBW to ONL line seeing a return of VFR. Low stratus persists southeast of this line much of today. By tonight, a westward expansion in low stratus and fog is expected again towards the Highway 83 corridor and will lead to another period of IFR/LIFR conditions tomorrow morning.

Winds increase from the south this afternoon, at around 10 to 15kts.

LBF WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory until 10 AM CST /9 AM MST/ this morning for NEZ028-029-038-057>059-069>071. Winter Weather Advisory until 9 AM CST this morning for NEZ038- 059-070-071.