Area Forecast Discussion

KEY MESSAGES

- Warm and dry conditions through Tuesday. Expect some rises on streams and rivers due to mountain snowmelt. Use caution with any burning.

- Strong weather system will bring cooler, wetter, and windier conditions to the region late Wednesday into the second half of the week.

UPDATE

Today will be a nice Spring day with highs in the 60s to lower 70s (F) under sunny to mostly sunny skies. Winds will be a bit less than yesterday as well with gusts in the teens to 20s mph. Overnight lows to tonight into Monday morning are forecast to be in the 30s to 40s (F). Arends

DISCUSSION

Through Saturday...

The building ridge over western North America will continue to dominate though the first part of this week. Rising heights will allow for temperatures to continue to rise each day through Tuesday. Temperatures on Saturday were roughly as forecast, however, humidity was notably lower than expected. The lower humidity will allow for wider temperature fluctuations which could aid in temperatures reaching much above average over the next few days. High 60s and low 70s are forecast area-wide today followed by 80s Monday and Tuesday. The higher percentiles of ensembles actually give some locations, including Billings, highs approaching 90F on Tuesday. These warm and dry conditions will thankfully not be accompanied by any strong synoptic winds which should keep grassfire concerns minimal. That being said, still use extra caution with any burning activities during this timeframe. With these warm temperatures both during the day and at night; snowmelt is expected up to roughly 9 kft in all the area mountains. While no flooding is expected, there will likely be rises on many of the creeks and streams in the foothills regions.

Towards the middle and end of the week a cutoff low / high amplitude trough is forecast to move into the intermountain west. There is still a ton of discrepancies between models and even between model runs. Some runs bring in a negatively tilted upper level trough which allows us to tap into moisture from the gulf and put the CWA in good diffluence aloft which could be a setup for strong thunderstorms on Wednesday. Other runs keep the trough oriented more meridional which would still give good precip chances to the region, but minimal thunderstorm threat. In terms of the system exiting the region there is also a ton of discrepancies. Some model runs push the feature out of the area by the weekend while others setup a blocking pattern and keep the upper level low over the prairie provinces through next weekend giving eastern MT repeated chances of precipitation; including chances for accumulating snow. In short, it is looking increasingly likely that an impactful system is in store for the region mid to late week but what impacts and timing remain large questions.

There is higher confidence in temperatures cooling off considerably into the weekend though. While Billings has a 30% chance of seeing a high of 90F on Tuesday, they have a 70% chance of seeing a high below 50F on Thursday. In addition to these cooler temps, this strong upper level low could also usher in some very windy conditions for the entire region with the entire CWA having at least a 50% chance of seeing gusts in the 50s mph Thursday and/or Friday. It is time to break out those shorts but at the same time keep those sweatshirts ready because this week will be a wild weather whiplash. WMR

AVIATION

VFR conditions will prevail over the region through the forecast period. No significant weather threats to aviation are expected through today. BT

PRELIMINARY POINT TEMP/POPS

Tdy Mon Tue Wed Thu Fri Sat ------------------------------------------------------- BIL 070 044/080 049/085 055/080 039/048 030/049 028/048 0/U 00/U 00/U 15/T 88/W 33/W 22/W LVM 068 040/077 047/082 051/071 035/045 025/045 025/047 0/U 00/U 01/B 16/T 87/W 33/J 22/J HDN 070 037/080 044/087 053/083 037/049 028/049 026/050 0/U 00/U 00/U 15/T 88/W 33/W 22/W MLS 067 038/078 044/086 054/086 038/048 028/045 025/044 0/U 00/U 00/U 02/T 78/W 32/J 21/B 4BQ 066 038/077 045/085 054/084 037/047 028/045 025/045 0/U 00/U 00/U 01/B 68/T 42/J 21/B BHK 061 035/075 042/084 051/085 035/048 025/043 022/042 0/U 00/U 00/U 01/B 47/T 42/J 11/B SHR 064 035/076 041/083 049/078 034/046 023/045 022/046 0/U 00/U 00/U 13/T 79/W 43/W 33/J

BYZ WATCHES / WARNINGS / ADVISORIES

MT...None. WY...None.