textproduct: Glasgow

KEY MESSAGES

- Fog and low stratus are expected across the northeast tonight into Thursday morning.

- Warm and dry conditions continue through Monday.

DISCUSSION

Today through tonight: Early morning fog across Sheridan county has burnt off as of 10AM. For tonight, most models pull the surface trough back southwest as a back door front. Behind this front will be lingering low stratus clouds and fog. What little is left of the CAMs after losing the NAM and ARW breaks into two camps with one (RRFS) showing just low stratus drifting across and becoming FOG on just the high terrain while the second camp (HRRR/RAP) show FOG moving all the way down to the low terrain and socking in many locations. With no more NAM/ARW, which were the best for this situation, had to tie break and split the difference with fog reaching KOLF and KSDY but not Glasgow. This could easily change in future updates into the evening hours. With massive uncertainty here and no physics packages to ensemble for a better solution, will be keeping eyes on observations up to the last minute for the best solution.

Thursday afternoon to Monday: Above normal temps of 10 to 15 degrees remain across the region though the weekend as a ridge plops itself over the front range and sits for a long period. Conditions should remain dry as well.

Tuesday onward: Model ensembles break apart here with the GEFS dragging the ridge out east and replacing it with a trough, while EC grouping remaining in place or washes the ridge out slowly. Low confidence from here onward.

FORECAST CONFIDENCE & DEVIATIONS:

- Had to step in and add fog across the northeastern half of the CWA as the NBM/GLAMP was not putting in anything while remaining CAMs had disagreements for fog placement. High Confidence through Sunday for most of the forecast.

Low Confidence in fog placement tonight.

Moderate confidence Sunday night to Monday night.

Low confidence from Tuesday onward.

GAH

AVIATION

LAST UPDATED: 1600Z.

FLIGHT CAT RANGE: VFR - MVFR (IFR?)

DISCUSSION: Mid-level clouds will persist throughout the day as a backdoor front marches from northeast to southwest. By the late evening hours the front will have passed over most terminals and begun to drag some low stratus that will hold on into the night.

Ensemble data is un-resolved with half dragging the clouds to the ground for FOG and impacting KOLF and KSDY, and the other half saying that it will just be low stratus. With no NAM or ARW anymore to break the tie, will split the difference with low clouds and reduced Visibilities down to MVFR from 09Z through 15-16Z. Again with no tie breaker CAMs, the forecast is now much more uncertain, and likely to change up to the last minute. IFR is not out of the realm of possibility(10-30%).

WIND: Light and variable through today. becoming E to SE this evening and increasing to 5 to 15 kts overnight behind the front into Thursday.

GAH

GGW WATCHES/WARNINGS/ADVISORIES

None.