040 FXUS63 KGID 190937 AFDGIDArea Forecast Discussion National Weather Service Hastings NE 437 AM CDT Fri Sep 19 2025
.KEY MESSAGES...
- Scattered thunderstorms expected today. A few could become severe late this afternoon and into the evening, primarily in the SW half of the area.
- Only a low (20%) chance for a few thunderstorms on Saturday.
- Better chances (40-50%) for thunderstorms return to the area Monday night into Tuesday.
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.DISCUSSION... Issued at 436 AM CDT Fri Sep 19 2025
There remains some potential for patchy fog to develop this morning, mainly in southwestern parts of the area. There isn`t much visible on satellite, but North Platte recently dipped to 1/4 to 1/2 mile visibility, indicating that there is some fog in low-lying areas. Any fog that does develop into our area should be very patchy and relatively short-lived.
At the same time,satellite shows low stratus slowly dipping south over northern Nebraska. This cloud cover, combined with additional convective development late this morning through this afternoon may prevent some areas north of I-80 from even reaching 70 degrees. Meanwhile, portions of northern Kansas could easily climb into the low-mid 80s. Quite the temperature gradient!
CAMs still generally depict one cluster of showers/storms developing near or just SE of the Black Hills this morning in response to a shortwave tracking around the large upper low. This activity would eventually track into at least northern parts of the forecast area late this morning into the early afternoon. Previous models were more bullish on this impacting a larger portion of the area...but the 06Z HRRR (and NAMnest to a lesser extent) have backed off a bit. The lack of instability will limit the severe risk with this activity.
Later this afternoon and evening, additional thunderstorms are expected to initiate in southwest parts of the area in the vicinity of a warm frontal boundary. Available instability is still the biggest question regarding the strength of these storms...but diurnal heating should result in MLCAPE values in the 1000-1500J/kg range in at least localized areas. Strong deep-layer shear (40-50kt) will be more than sufficient for supercells supporting large hail and localized damaging wind. The exact evolution of storms is still somewhat uncertain, but the primary threat area is from Lexington to Mankato and areas southwest...in the 5-10pm timeframe. Some non-severe elevated storms could then linger overnight and into early Saturday morning.
Low stratus is expected to develop Saturday morning, and lingering cloud cover will keep temperatures on the cooler side (low-mid 70s) on Saturday. There is still a low chance for thunderstorms Saturday night, but this has been trending further south.
Sunday and Monday trend warmer ahead of an approaching upper low. Most areas will see highs in the 80s on Monday...about 5 degrees above normal for late September. Thunderstorm chances then return Monday evening into Tuesday as this upper low slowly pushes into the area. A few strong to severe storms cannot be ruled out, although mesoscale (and even some synoptic- scale) details remain too uncertain to provide much specifics.
Tuesday/Wednesday trend cooler with lingering rain/tstorm chances as the upper low slowly moves through the region. Generally dry conditions are favored for Thursday/Friday, although confidence is lower as global deterministic/ensemble models really start diverge on the upper level pattern at this point.
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.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1254 AM CDT Fri Sep 19 2025
For KGRI/KEAR Airports:
Stratus is expected to remain mostly north of EAR/GRI and any fog is expected to remain largely to the south/west. There is only a 10-20% chance for sub-VFR conditions through 15Z this morning.
Winds today will be quite variable...but generally shifting from the west...to north and then to east-northeast by this evening.
Scattered thunderstorms move through the area roughly 19-23Z, followed by a lower-confidence period of redeveloping thunderstorms in the 02-06Z timeframe.
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.GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None.
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DISCUSSION...Mangels AVIATION...Mangels
NWS GID Office Area Forecast Discussion