Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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171 FXUS63 KBIS 290920 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 420 AM CDT Mon Apr 29 2024 .KEY MESSAGES... - Showers will continue across central North Dakota this morning before diminishing and exiting to the east northeast by early this afternoon. - Light rain may become mixed with, or briefly change over to light snow early this morning central, while patchy fog is possible across the west. - An active weather pattern will be over the region through next week, with daily chances for precipitation and slightly below normal temperatures. - Critical fire weather conditions will be possible across southwest and portions of far south central North Dakota Tuesday afternoon through early Tuesday evening due to strong westerly winds and low relative humidity. && .DISCUSSION... Issued at 420 AM CDT Mon Apr 29 2024 This morning, an upper level low and associated surface low continues to progress across the the central Plains, eventually lifting into the northern Great Lakes region by the early evening period. Wrap around precipitation, falling mainly as light rain showers, continues over much of central North Dakota at this time, through is expected to begin to exit to the east northeast by around noon today. As surface temperatures begin to approach freezing over portions of the James River Valley this morning, periods where this rain becomes mixed with snow will become possible. With dewpoints remaining at or above freezing, however, little to no accumulations are anticipated to occur if at all. Along with these showers, a broad area of low clouds lingers over much of the forecast area this morning, though not stretching far enough west to reach the Montana border. This continued clearing in the west as the cloud deck moves to the east northeast will allow for periods of patchy fog to become possible over the west this morning, as well as subfreezing low temperatures. Otherwise, winds are expected to remain fairly light and variable through the morning, while high temperatures today are expected to range from the upper 40s in the east central where the remains mostly cloudy, up to the mid 60s where the sky becomes mostly sunny to partly cloudy. An active pattern then continues through much of the week, with upper level pacific low organizing over the Canadian Prairies late today into early Tuesday, before it and an associated surface systems pushes into the forecast area by late Tuesday morning. With the passage of this system, gusty winds approaching advisory criteria are expected to developing across portions of the southwest Tuesday afternoon. These winds, along with the intrusion of much drier air promoting relative humdities down to around 18 percent over portions of the southwest, lead to increased fire weather concerns in this area Tuesday afternoon (see Fire Weather Discussion. More showers are also anticipated with this system, pushing broadly from west to east through the early afternoon before swinging northward by late Tuesday night as the upper level low stalls over southern Manitoba. This initial wave of precipitation could see portions of the north exceed more than 0.5" by late Tuesday night (20-40% chance). While light precipitation could linger over the International Border, the rest of the forecast area should dry out for Wednesday. A series of energetic shortwave are then expected to swing around the stalled low first late Wednesday night into early Thursday morning then again Friday into Saturday, promoting off and on chances (30-50%) for rain each day conditions dry out by Sunday. All told, we could anticipate another 0.25" to 0.75" of precipitation through this period, though there remains a lot of discord between ensemble members at this time with regards to how slowly the system progresses out of our area. Temperatures this week remain broadly at or slightly below seasonable normals, with highs in the lower 50s to mid 60s and lows from the lower 30s to lower 40s. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 420 AM CDT Mon Apr 29 2024 Widespread MVFR to IFR ceilings are present at most terminals at the start of the 06Z TAF period, with the exception of the northwestern terminal of KXWA which remains at VFR conditions. Light rain showers are expected to continue over the south central, presently affecting the terminals of KBIS and KJMS and promoting occasional LIFR conditions, before clearing from west to east through the early morning. Rain at KJMS is anticipated to briefly become mixed with or completely transition over to light snow during to coolest hours of the morning. Patchy fog is expected to develop over portions of the west this morning, mainly affecting the southwestern terminal of KDIK, before diminishing by the mid morning hours. MVRF ceilings will similarly degrade while moving eastward through the morning, with all terminals improving to VFR conditions from west to east through the late morning and afternoon period. Winds will generally diminish, remaining generally light and becoming southerly through the end of TAF period. && .FIRE WEATHER... Issued at 420 AM CDT Mon Apr 29 2024 Critical fire weather conditions are possible Tuesday afternoon through early Tuesday evening over southwestern and portions of south central North Dakota. Minimum relative humidity values as low as 18 percent along with strong westerly winds with sustained speeds around 30 mph and gusts up to 45 mph in this area. Previous near-critical fire weather concerns north of the fire weather watch have diminished with the latest model runs. Minimum relative humidities in the upper teens and lower 20s are now more strictly bounded by the already existing watch area, along with an overall lowering of wind speeds supported by model soundings. As such, previous mentions of near-critical fire weather concerns in the area north of the fire weather watch and bounded on the north by Lake Sakakawea and the Missouri River have been removed. && .BIS WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Tuesday afternoon through Tuesday evening for NDZ031>033-040>045. && $$ DISCUSSION...Adam AVIATION...Adam FIRE WEATHER...Adam