textproduct: Great Falls

KEY MESSAGES

- Hot temperatures continue for another day.

- Afternoon temperatures next week will continue to be very warm most days.

- The chance for showers and thunderstorms increase by Tuesday, with some storms producing heavy rainfall.

DISCUSSION

- Meteorological Overview: An upper level ridge of high pressure will reside over the CWA through Sunday. Expect another hot afternoon Sunday, with some record afternoon daily high temperatures. With the airmass a bit dry, the feels like temperature will actually be up to 5 degrees cooler in some areas on Sunday. Thus I will continue with the heat advisory. Do expect a wind shift on Sunday afternoon though over North Central MT.

For Monday through Saturday, the upper level ridge breaks down slightly. This will result in afternoon temperatures not quite as hot as this past weekend, but still very warm. Also, several upper level disturbances will start to move through the CWA starting as early as Monday evening. This will result in almost daily chances for showers/thunderstorms over the CWA. (This will also help keep temperatures down a bit.) Some of the storms could also produce heavy rain, and isolated severe storm can not be ruled out.

- Forecast Confidence & Scenarios: The main concern this upcoming week will be for thunderstorms producing heavy rainfall. Precipitable water is near 1.50 inches over portions of North Central MT by Tuesday. This could result in heavy rainfall with any thunderstorms that do develop. This a marginal risk has been issued for portions of the CWA for Tue and Wed for the potential of flash flooding. Brusda

AVIATION

11/18Z TAF Period

Mostly clear skies and dry conditions are expected during the TAF period. Breezy southwest winds pick up this afternoon with winds decreasing in the evening. -Wilson

FIRE WEATHER

Expect a wind shift on Sunday over North Central MT during the afternoon, while hot temperatures, low humidity and breezy winds are expected across the CWA. Southwest MT is the one area where fuels have dried out, so portions of Southwest MT are now under a Red Flag Warning for Sunday. Expect thunderstorms by the middle of next week, with some storms producing heavy rainfall. Also, afternoon temperatures will not be quite as hot as this past weekend. Brusda

PRELIMINARY POINT TEMPS/POPS

GTF 61 101 63 97 / 0 0 0 0 CTB 58 91 61 91 / 0 0 0 0 HLN 63 100 65 97 / 0 0 0 0 BZN 60 103 60 98 / 0 0 0 0 WYS 48 97 50 95 / 0 0 0 0 DLN 55 99 58 94 / 0 0 0 0 HVR 62 102 63 98 / 0 0 0 0 LWT 59 104 59 98 / 0 0 10 0

TFX WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 9 PM MDT Monday for Bears Paw Mountains and Southern Blaine-Canyon Ferry Area-Cascade County below 5000ft- Eastern Pondera and Eastern Teton-Eastern Toole and Liberty- Fergus County below 4500ft-Gallatin Valley-Gates of the Mountains-Helena Valley-Hill County-Judith Basin County and Judith Gap-Madison River Valley-Missouri Headwaters-Northern Blaine County-Southern High Plains-Western and Central Chouteau County.