Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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263 FXUS63 KBIS 081745 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 1245 PM CDT Sat Jun 8 2024 .KEY MESSAGES... - Isolated showers possible today with the highest chances (20 percent) over the northwest and west-central (Crosby, Williston, Watford City, Killdeer, Beach, Medora). - High temperatures the next few days normal to just below for early June (normal is mid 70s). Above normal temperatures are expected with increasing confidence for Wedneday (80-85 degrees). - Widespread showers and non-severe thunderstorms expected (70 percent chance) Monday afternoon and Monday night. Then stronger thunderstorms possible Wednesday. && .UPDATE... Issued at 1245 PM CDT Sat Jun 8 2024 Made some minor edits to the sky grids, and have extended the isolated showers further east to account for the latest radar trends. Otherwise, the forecast remains on track. No observations of rain have been made out of the reflectivity over the northwest and north central so far, with most of any precipitation evaporating before reaches the ground as dewpoint depressions of 20-30 degrees persist over this area. UPDATE Issued at 840 AM CDT Sat Jun 8 2024 The forecast remains on track at the time of this update. Weak radar returns continue to approach our northwest out of Montana and southern Saskatchewan, though only isolated showers are expected once it arrives later this morning. Mid to high level clouds have begun to push into the west. Winds broadly remain light from 5 to 10 mph, and loosely out of the west northwest. UPDATE Issued at 640 AM CDT Sat Jun 8 2024 Current forecast right on target as far as radar and satellite tools. && .DISCUSSION... Issued at 430 AM CDT Sat Jun 8 2024 Have gone back and forth on what to do with pops today (Saturday). NBM yielded no pops for today that would result in a forecast of a chance for rain while the CAMs indicate an isolated nature to any showers that do form. As far as location, depending on which CAM was used, resulted in isolated shower chances all but the Jamestown area at one or another point today. Concern for rain today is that the features that would produce showers are weak, the best of which is slightly cyclonic flow aloft. To some extent that is countered by the surface high in Montana ridging into North Dakota and providing subsidence and relatively dry air from the surface into the mid levels. We were wondering if it is a virga scenario today where rain falls from a cloud that can get some vertical growth, but evaporates before reaching the ground. The highest chance of a shower, and it is not high, is over the northwest and west- central, with the strongest, though not very strong, cyclonic flow / troughing aloft, and at least some instability, on the order of 200 J`kg. In collaboration with NWS Glasgow, Montana, we have added a low pop along the MT/ND border and came as far east as Stanley and Killdeer and as far south as Beach and Medora. Temperatures today just a few degree lower than what was seen on Friday. Guidance has shifted away from bringing the H5 low out of Canada and across North Dakota on Sunday. With that then the pops are lower and the high temperature forecast is, well, not as low. H5 ridging Sunday and Sunday night should result in dry weather. For Monday, a long wave H5 trough approaches with southwest flow aloft and an approaching warm front that will be the focus for widespread convection, especially Monday afternoon into the night. Guidance is in agreement and so confidence is high in that. There continues to be a wide spread in possible outcomes for high temperatures in the Tuesday through Thursday time period. With that said they are higher (warmer) than previously expected and so confidence remains high that 80s will be common over the forecast area say on Wednesday (west on Tuesday as well, and east on Thursday as well). With that thermal ridge axis over us on Wednesday, and with instability and wind shear progged to be increasing that day on southerly flow ahead of a cold front, SPC has highlighted the eastern Dakotas on the Day 4 Outlook. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1221 PM CDT Sat Jun 8 2024 VRF ceilings and visibility are anticipated at all sites through the 18Z TAF period. Some isolated showers falling primarily as virga will be possible across the northwest and north central through this afternoon. Winds will remain generally light out of the northwest, with KXWA and KJMS experiencing some gusts up to around 20-25 knots through the early afternoon. Winds then turn northerly and diminish overnight and remain light through the end of the TAF period. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Adam/JPM DISCUSSION...JPM AVIATION...Adam