Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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141 FXUS63 KBIS 081157 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 657 AM CDT Wed May 8 2024 .KEY MESSAGES... - Low to medium chances for rain showers remain in the forecast today, highest in western North Dakota. - Low chance for a few thunderstorms, possibly strong, in McIntosh and Dickey Counties during the late afternoon and early evening hours today. - A transition to warmer and drier weather is expected Thursday through the weekend. && .UPDATE... Issued at 657 AM CDT Wed May 8 2024 Early morning satellite shows cloud cover slowly eroding from east to west over south central North Dakota. While sunshine could be more plentiful there this morning, diurnal cumulus is likely to develop in the afternoon. Back to the west, a localized area of dense fog has developed over Stark and southern Dunn Counties. Confidence on the duration of this fog remains low, as it is associated with a low cloud deck and commenced when northeast surface winds began increasing. Recent high-resolution guidance shows a slightly increased chance of a few thunderstorms near the South Dakota boarder in Dickey and McIntosh Counties during the late afternoon and early evening, which is forecast to lie in the northeast quadrant of the surface low. RAP guidance shows up to around 500 J/kg CAPE with effective bulk shear decreasing with time. A stronger storm or two cannot be completely ruled out in this part of the state later today, but severe weather is not expected. However, there is also a signal in RAP guidance for funnel clouds/landspouts, with forecast non-supercell tornado parameter values as high as 3. Will not be strongly messaging this potential yet, but mesoscale features will bear watching later today. It appears though that the highest NST potential will remain south of the stateline. && .DISCUSSION... Issued at 355 AM CDT Wed May 8 2024 An occluded surface cyclone is centered near Dickinson early this morning, with the parent upper low having retrograded back closer to the MT/ND/SD border intersection. While widespread cloud cover continues to circulate around the low, shower activity overnight has been confined to only far western parts of the state, and even there it is becoming more isolated early this morning. The low is forecast to gradually weaken and slowly drift southward into western South Dakota throughout the day today. The continued presence of cyclonic vorticity rotating around the top of the low keeps a 20 (central ND) to 40 (western ND) percent chance of showers in the forecast for today. Temporally, there are higher chances for showers in the afternoon than the morning, owing to the diurnally-driven destabilization of the boundary layer. Model soundings in south central North Dakota show some deeper buoyancy potential, but this is where the lowest shower chances are located spatially, and the moisture profile is drier there. Elsewhere, the depth of the buoyant layer is projected to be much shallower. Therefore, the probability for a thunderstorm across all of western and central North Dakota this afternoon is quite low. The positioning of the surface low will bring breezy northeast winds to northern and western North Dakota today, with lighter winds elsewhere. An overall decreasing trend in loud cover should allow for a slightly warmer afternoon, with highs forecast in the mid 50s southwest to mid 60s central and east. Low chances for isolated showers remain in the forecast overnight into Thursday morning, but diminish from north to south over time. The influence of the low will finally depart the local area on Thursday as a west-east oriented upper ridge slides in. This should allow temperatures to rebound to near normals for this time of year, with low NBM spread implicating high confidence in highs on Thursday around 65 to 70. A weak mid to lower level trough coming down from Saskatchewan could bring some isolated showers into the state late Thursday afternoon and evening, as a handful of CAMs are projecting. But the rising heights aloft are likely to greatly limit this potential. A clipper-like system remains on track to dig into the Upper Mississippi River Valley and western Great Lakes regions on Friday, though its forecast track has consolidated a little farther to the east. Western and central North Dakota are now less likely to see diurnally driven showers Friday afternoon, but breezy conditions can still be expected. The high temperature forecast for Friday is very similar to Thursday at around 65 to 70. While ensembles strongly favor a northwest flow pattern over the weekend, there still uncertainty on whether any disturbances will bring any showers or storms through the area. There is growing confidence in above normal highs well into the 70s on Saturday as a stronger wave farther north over Canada ushers a thermal ridge into the Northern Plains. Confidence in the synoptic pattern begins to lower considerably as early as Monday, with signs of a more active quasi-zonal pattern that could potentially be followed by a larger central CONUS trough mid next week. The ensemble consensus temperature outlook maintains near to above normal temperatures through the middle of next week, but there is a minority outcome for cooler temperatures by the end of this time period. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 657 AM CDT Wed May 8 2024 Dense fog with an LIFR ceiling has once again developed at KDIK early this morning. The most likely outcome is for visibility to improve and ceilings to slowly lift by late morning, but forecast confidence is low. Across the rest of the western half of the state, mostly MVFR ceilings with periodic IFR ceilings are observed at the start of this forecast period, with VFR conditions at KJMS. The overall expectation is for a gradual improvement to VFR ceilings this afternoon. Isolated to widely scattered showers remain possible this forecast period, mainly across the west and north central. The strongest winds for this forecast period will be across northwest and north central North Dakota, with east to northeast winds around 15-20 kts. South central North Dakota (KBIS to KJMS) will see lighter southeast winds this morning, turning to the east later in the day. At KDIK, northeast winds will increase to near 15 kts this afternoon. All terminals should see decreasing winds become more northerly this evening through tonight. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Hollan DISCUSSION...Hollan AVIATION...Hollan