Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/03/21

Area Forecast Discussion
National Weather Service Bismarck ND
859 PM CDT Fri Apr 2 2021 .UPDATE... Issued at 859 PM CDT Fri Apr 2 2021 The Red Flag Warning was allowed to expire on time. For this update, we decided to issue a Fire Weather Watch for south central North Dakota and the James River Valley Saturday afternoon and early evening. There is high confidence in relative humidity falling into the 10 to 15 percent range across nearly all of western and central North Dakota. The watch was limited to areas where there is higher confidence of sustained winds reaching 20 mph. This area also contains a wind direction shift from southerly early in the afternoon to westerly by late afternoon. UPDATE Issued at 536 PM CDT Fri Apr 2 2021 Critical fire weather conditions continue across much of the area late this afternoon, with a wide swath of northwest winds around 20 mph overlaying relative humidity under 20 percent across central North Dakota, and closer to 10 percent in south central North Dakota. Parts of LaMoure and Dickey Counties may see an hour or two of critical fire weather conditions before sunset, but this duration does not warrant them being added to the ongoing Red Flag Warning. We are now evaluating the potential for another round of critical fire weather conditions tomorrow. All of western and central North Dakota is expected to see minimum relative humidity drop into the 10 to 15 percent range. The strongest winds of around 20 to 25 mph out of the south are expected from the Missouri and James River Valleys up to the Devils Lake Basin. We will continue to evaluate the most recent guidance and make any adjustments to the forecast as needed. && .SHORT TERM...(This afternoon through Saturday night) Issued at 245 PM CDT Fri Apr 2 2021 Fire weather concerns continue to be the main weather story for the short term forecast period. The general story remains the same for this afternoon through Saturday, just with slightly different details. Relative humidity values across almost all of western and central North Dakota continue to dive. Hettinger airport is currently observing the lowest humidity value of 9 percent but others will likely follow, dipping below 10 percent. Much of the area is currently sitting below 20 percent. Winds also continue to increase with more afternoon mixing. Behind a surface pressure trough (currently approaching the southern James River valley), winds will be out of the northwest sustained around 20 mph. Gusts up to 30 mph will be possible. Thus, the Red Flag Warning looks to be in good shape. Thus far abundant high clouds haven`t really impacted temperatures or mixing and clearing has already started across the northwest. Tonight, winds will relax, humidity will come up, and fire weather conditions will improve. Expect lows in the 30s. As we turn the page to Saturday, fire weather concerns present themselves to be a challenge once again. Near critical fire weather conditions will be possible across pretty much all of western and central North Dakota, but another Red Flag Warning will likely be needed somewhere across the area. At this time, the most likely area will be generally across the far south central and east of the Missouri River. Here, afternoon humidity values will range from 10 to 20 percent, overlapping sustained northwest winds up to 25 mph and gusts to 35 mph. Elsewhere the very dry air will be in place, but winds will be lower. That being said, there is still some uncertainty about how widespread the sustained winds of 20 mph or greater will setup. Because of this uncertainty and the fact that we already have a Red Flag Warning out for today, we will not be issuing headlines for tomorrow yet as to avoid any confusion. For today`s dewpoints, stuck with the latest time lagged HRRR as it typically does very well in these setups. And for tonight and tomorrow, generally went with the latest time lagged RAP. Regarding high temperatures for Saturday, stuck with the trend of using the NBM 75th percentile which brings widespread 70s to the area with a few lower 80s across the far southwest. Broad ridging starts to nudge in Saturday night and we will see lows mainly in the 30s with a few lower 40s across the south. .LONG TERM...(Sunday through Friday) Issued at 245 PM CDT Fri Apr 2 2021 Another very warm day will be in place on Sunday. There continues to be quite a bit of spread in the NBM for highs. Guidance suggests that widespread cloud cover will be in place for much of the day so it may be hard to reach into the upper percentiles of the guidance. Thus, we decided to stick with the 50th percentile for highs on Sunday which still bumped the values up a bit from raw NBM output. Near critical fire weather conditions will once again be possible on Sunday, but winds will be lighter. A shortwave riding across the broad ridge (north of the International Border) will flatten the flow on Monday, transitioning us into a zonal pattern at least briefly. This will lead to cooler temperatures and we also went with the NBM 50th percentiles for Monday`s highs, nudging them up slightly from the raw NBM output. A more appreciable pattern change looks to start on Tuesday as a west coast trough digs and approaches. Still quite a bit uncertainty. At first glance, the deterministic global models look to be in better agreement bringing a closed upper low from Wyoming into the central or northern Plains Tuesday into Wednesday. However, looking at the latest WPC cluster analysis and various ensemble members, it is apparent that a very wide envelope of solutions are still on the table, so caution is advised in trusting any deterministic solutions at the moment. Still, it appears that there is at least some possibility of widespread precipitation somewhere across the central or northern Plains in the Tuesday through Thursday time frame. For now we will keep mention of slight chance to chance PoPs in the forecast Tuesday through Thursday morning with the best chances on Wednesday across the south. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 647 PM CDT Fri Apr 2 2021 VFR conditions are expected through the forecast period. Northwest winds will diminish this evening. Wind direction will then make a complete clockwise turn, coming back to the northwest late Saturday morning through the early evening. Sustained winds will reach around 15-20 kts Saturday afternoon, strongest at KXWA and between KBIS and KJMS. && .BIS WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Saturday afternoon through Saturday evening for NDZ022-023-025-034>037-042-045>048-050-051. && $$ UPDATE...Hollan SHORT TERM...ZH LONG TERM...ZH AVIATION...Hollan
Area Forecast Discussion
National Weather Service Dodge City KS
657 PM CDT Fri Apr 2 2021 ...Updated Aviation Section... .SHORT TERM...(This evening through Saturday) Issued at 300 PM CDT Fri Apr 2 2021 Very strong south to southwest winds across southwest Kansas today underneath a 40-50 knot low level jet at 850 mb. A few gusts to around or over 50 mph were noted just before midday. This mornings RAP model guidance has been showing the low level jet weakening somewhat and propagating to the east. Latest surface winds/gusts at 2 pm are showing a decreasing trend and this will continue to be the case through the rest of today. Upper air analysis showed strong westerly flow aloft over the northern Rockies and adjacent Plains States. Weaker flow was noted farther south with a closed upper low over Arizona moving east. A weak disturbance moving out over the northern Plains will push a weak cold front into central and southwest Kansas late tonight which will stall out on Saturday. The decreasing winds overnight along with lower dewpoints will allow temperatures to fall into the mid 30s to lower 40s. Winds on Saturday will be fairly light compared to today with variable winds at 5 to 10 mph expected. With high temperatures in the upper 70s to lower 80s, Saturday is shaping up to be be a fine Spring day. .LONG TERM...(Saturday night through Friday) Issued at 300 PM CDT Fri Apr 2 2021 The extended period will see a continuation of the upper level westerly flow pattern. This will be conducive to redevelopment of a low pressure trough in the lee of the Rockies with a strengthening pressure gradient and return to gusty south winds across western Kansas on Sunday. Some of the models are breaking out isolated to widely scattered thunderstorms near the surface trough over far western Kansas on Sunday afternoon into early Sunday evening. CAPE and shear values are not overly strong. Inverted V sounding profiles would suggest high based showers and thunderstorms with virga along with downburst wind potential. Another upper low is forecast to drop into the Pacific Northwest on Monday and then move east across the northern Plains through mid week. Gulf moisture will get pulled northward into the central Plains as broad scale southerly flow develops ahead of this system. Surface dewpoints could increase into the 50s across central and eastern Kansas. While details are vague at this time, there could be potential for dryline thunderstorms somewhere across central and adjacent portions of southwest Kansas Tuesday afternoon. A cold front will also push through the region by Tuesday evening as the upper system moves east. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 653 PM CDT Fri Apr 2 2021 Strong south winds at the onset of this TAF period will decrease in strength through the evening. The south to southwest wind will eventually become a light and variable wind at speeds of 6 knots or less during the day Saturday as a trough axis moves east and stalls out across southwest and west central Kansas. Flight category will remain VFR through this TAF period amidst a continued dry lower atmosphere and absence of deep moisture advection from the south/southeast. && .FIRE WEATHER... Issued at 300 PM CDT Fri Apr 2 2021 Near Red Flag conditions will continue through the rest of this afternoon. Strong south to southwest winds will continue through the rest of today across all but the far west central Kansas counties. Relative humidity should bottom out in the upper teen to lower 20 percent range with a few locations in the far southwest falling to around 15 percent for a few hours. Conditions will be much improved on Saturday with much lighter winds but elevated to near critical conditions could redevelop late in the weekend and early next week as southerly winds increase. && .PRELIMINARY POINT TEMPS/POPS... DDC 43 80 49 83 / 0 0 0 0 GCK 39 80 47 83 / 0 0 0 10 EHA 40 81 47 83 / 0 0 0 20 LBL 40 82 46 83 / 0 0 0 0 HYS 41 80 48 84 / 0 0 0 10 P28 43 77 48 81 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 7 PM CDT this evening for KSZ031-046-065- 066-079>081-089-090. && $$ SHORT TERM...Gerard LONG TERM...Gerard AVIATION...Umscheid FIRE WEATHER...Gerard
Area Forecast Discussion
National Weather Service Marquette MI
812 PM EDT Fri Apr 2 2021 .SHORT TERM...(This evening through Saturday) Issued at 339 PM EDT FRI APR 2 2021 Water vapor imagery and RAP analysis show mid-level ridge extending from the Plains into the Upper Great Lakes and Hudson Bay. At the sfc, a tightening pres gradient between high pressure se into the Ohio Valley and a trough approaching from the Northern Plains has resulted in somewhat gusty south winds of 20-25 knots this afternoon. These gusty winds mixing through a very dry attendant air mass has also led to RH values in the 15-25 pct range and elevated wildfire concerns. A SPS will remain in effect through 00Z this evening for gusty winds and low RHs for Alger and Delta counties westward. Weak shortwave and an associated sfc trough/frontal boundary approaching from southern Saskatchewan/eastern Dakotas will reach Upper MI by 12z Sat. Models indicate any waa/isentropic ascent pcpn from system will stay north of Upper Mi tonight into Sat. Gusty winds of today will continue into at least the evening hrs across the n, in particular the downslope areas of n central Upper MI (Marquette County eastward), as 40-45kt low-level jet translates across the area. Continues to incorporate guidance from the HRRR to raise winds and gusts as it performs well with such events. Expect gusts up to around 35mph. The combination of gusty winds and continue dry dew points will lead to relatively poor RH recovery (not much better than 60%) for downsloping areas along Lake Superior. Look for min temps mostly in the 30s, except for a few upper 20s readings over the interior. As the weak shortwave and associated sfc trough push into the area on Saturday, expect continued mostly sunny, dry and even warmer conditions. Look for highs in the 50s most areas with even lower 60s possible over the interior west near the WI border. Closer to the shorelines east of Marquette on Lake Superior and along Lake Mi readings may stay in the 40s with enhanced lake breezes developing. Did again side at or below the lower end of guidance for dew points on Saturday given the dry air mass still in place and decent mixing fcst. Using the mixed dew point tool and blending with bias- corrected MET guidance yielded dew points in the 20s across much of the area which drops min RHs into the 25 to 30 pct range over portions of the interior west. Fortunately, lighter winds with gusts more in the 10-15 mph range should help limit elevated wildfire concerns. .LONG TERM...(Saturday night through Friday) Issued at 423 PM EDT FRI APR 2 2021 A highly anomalous blocking ridge across the North Atlantic Ocean will be the stalwart of the long-term pattern. The general consensus among ensemble guidance is for the blocking ridge to retrograde toward the Hudson Bay late next week resulting in increasingly split flow aloft. A series of undercutting troughs and potential for interactions among those troughs will be the primary weather makers throughout the long range. In general, above normal temperatures prevail with precipitation chances increasing Sunday night into Monday night then falling somewhat Tuesday through the end of the week. However, forecast confidence decreases quickly on Tuesday as a substantial trough enters the Plains and tracks east through the end of the week. The long-term period begins with a broad ridge over the Central Plains. NAEFS analysis indicates 500 mb heights associated with this ridge exceed the 99.5th percentile across large portions of CO, WY, NE, and KS. Upper Michigan will initially be within a northwest flow regime on the northeast side of this ridge. The ridge axis shifts east into our CWA on Monday as a sharp shortwave trough moves across the Canadian Prairies. This shortwave advects a plume of rich moisture (NAEFS Pwat > 90th percentile) beneath and EML with 850 mb temperatures >5C. The combination of relatively rich moisture and steepening mid-level lapse rates (>7C/km) should result in up to 1000 J/kg of MUCAPE. Thus, there`s potential for a few rumbles of thunder with passing showers primarily on Monday night as a cold front moves across the area. I removed thunder from the grids for Monday evening/overnight since confidence is low (~15%) in thunderstorms actually materializing. The general consensus is for the frontal boundary to stall to our south on Tuesday with northerly flow resulting in cooler temperatures and extensive cloud cover. However, substantial differences in the track of the Canadian Prairies shortwave amplify by Tuesday as the next trough/closed low results in cyclogenesis on the Central Plains. Where the cyclone tracks next and how it interacts with lingering shortwave energy is difficult to know at this time. Ensemble clustering analyses for Wednesday evening indicates three solution clusters to choose from. Roughly 60% of ensemble members support a southeast trajectory from the Northern Plains into the Ohio Valley that leaves Upper Michigan in relatively dry northwest flow aloft. The remaining 40% of guidance is almost evenly split between easterly and northeasterly trajectories. An easterly trajectory implies a surface low tracking just to our south with widespread stratiform precipitation across Upper Michigan. A northeasterly trajectory implies a negative tilt trough with potentially heavier precipitation, but the blocking ridge to our northeast suggests this outcome is unlikely. The observed reality of local weather over the past 5 months favors drier solutions until a more coherent signal for wet weather emerges. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 812 PM EDT FRI APR 2 2021 Under a dry air mass, VFR conditions will prevail at KIWD/KCMX/KSAW through the forecast period. A low level jet over the area this evening will result in gusty south winds at times as well as LLWS. Winds will diminish late tonight and Saturday. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 339 PM EDT FRI APR 2 2021 Tight gradient ahead of incoming trough over the northern Plains will sustain fairly strong s-se winds of 20-30 kt into tonight, especially over the east half of the lake. Not out of the question that some high obs platforms could see a few gale force gusts this evening, including into the nearshore waters e of Marquette. Weakening sfc trough will cross Lake Superior Sat. With the relaxing pres gradient, expect winds blo 20kt across the lake. These lighter winds will continue into Sun. Building high pres to the ne and a low pres trof moving out across the Plains will then lead to increasing se-e on Mon. Wind gusts may increase back to the 20-30kt over eastern and north central portions of Lake Superior. The approaching trof will weaken as it crosses the lake late Mon night/Tue morning. As a result, winds should relax a bit for Tue. The approach of another low pressure system from the Central Plains will lead to increasing ne winds on Wed, especially over the west half where gusts could reach 25-30 knots over the western third. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Voss LONG TERM...EK AVIATION...JLB MARINE...Voss