SHORT TERM /THROUGH SUNDAY/
Issued at 338 AM CDT Sat Jul 27 2024

A stalled frontal boundary across the Nebraska panhandle will be the focus for isolated to scattered thunderstorm development late this afternoon and tonight. Winds aloft are very weak, just 10-30kts at h500-300mb but strong daytime heating and a weak UA disturbance moving through nrn UT/NV will move through for support. Moisture is beginning to pool ahead and behind the front and PWAT could reach 1.25 inches by this evening. The short term model blend plus the NAM, GEMreg, HRRR and RAP models was the basis for a 20 to 40 POP.

SPC suggested a marginal severe wind and hail threat today. Given the weak winds aloft, wind would seem to be the primary concern followed by severe hail.

The situation Sunday afternoon and evening is much different from Saturday. The models are in good agreement energizing the subtropical jet to 40-50kts at 300mb; around 30kts at h500mb.
Moisture will continue to pool with PWAT increasing to 1.50 inches east of highway 83 and 1.25 inches to the west. Strong warm air advection across KS/ern Colo will be directed toward wrn Nebraska and the models suggest sufficient moisture pooling will cause a weakness in the 700mb cap late in the afternoon around 21z or so.
The 00z HRRR indicated a couple of storms with 70 mph gusts across the Sandhills. The unidirectional westerlies aloft would seem to support bow segments as the severe storm mode but it is worth noting the rich moisture could easily support a hail threat. POPs are 20-30 percent for this event and use the short term model blend plus the NAM and GEMreg models.

SPC suggested a marginal severe wind and hail threat Sunday and this is based on the expected isolated storm coverage but given the winds aloft and moisture availability, one has to be concerned with the significant severe weather potential.

The short term model blend plus bias correct plus the NBM 50th percentile suggest highs in the low to mid 90s today, and mid to upper 90s Sunday. The target mixing height is 700mb both days and temperatures aloft at h700mb will warm from around 13C today to 14- 15C Sunday.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
Issued at 338 AM CDT Sat Jul 27 2024

An upper level low across the srn Plains this morning will slowly move northeast toward the Great Lakes this weekend. The upper low has caused a split in the subtropical upper level ridge with centers resting across the deep South and swrn U.S. Once the low moves away, the two upper level ridges will merge into a single large high pressure system across Texas. The ridge will then migrate west and build into the central Rockies by Friday.

The subtropical jet across Nebraska will peak at 60-70kts Monday morning followed by a gradual weakening becoming light at 20kts late Thursday and Friday. The potential for anything more than isolated storms is low and the reason for this is the lack of moisture. Low heights across the wrn U.S. are expected to limit subtropical moisture return into Nebraska.

The upper level trof will send a surge of hot desert air into Nebraska Tuesday. Highs in the 90s and low 100s are in place supported by h700mb temperatures around 16C and precipitable water of an inch or less. Otherwise, highs in the 90s are likely Monday and Wednesday through Friday as slightly cooler air moves in aloft.
Temperatures at h700mb will remain 13-15C.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
Issued at 620 AM CDT Sat Jul 27 2024

VFR conditions are expected to prevail across western and north central Nebraska through tomorrow morning outside of thunderstorms. Winds quickly strengthen from the south this morning, and remain gusty (20-25kts) through the remainder of this afternoon and into this evening.

Thunderstorms then push into the area from the west this evening, with brief MVFR and gusty, erratic winds. Timing of impacts of KLBF and KVTN remains lowered for now, so have maintained the previous forecast timing. Future amendments will likely be needed as confidence grows.

LBF WATCHES/WARNINGS/ADVISORIES
None.