Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/09/21

Area Forecast Discussion
National Weather Service Bismarck ND
1002 PM CST Mon Mar 8 2021 .UPDATE... Issued at 950 PM CST Mon Mar 8 2021 00Z guidance continues to suggest that mesoscale banding of precipitation will be possible across far northwest North Dakota mid Tuesday morning through the early afternoon. Little change in forecast thinking from the previous update discussion regarding this potential. One thing to add is that surface temperatures at the time of heaviest precipitation are expected to be near to slightly above freezing, which could yield rain, snow, or a mix thereof. This introduces more uncertainty for snow accumulation potential. For this update, we increased PoPs and QPF mainly across Williams, Divide, and Burke Counties. Our maximum event total QPF of around 0.10" matches well with that of the 00Z HREF localized probability-matched mean. Though looking at its individual members, it is more of a bimodal solution (less than 0.05" vs. around 0.25"). Because of the precipitation type uncertainty and low snow-to-liquid ratios, these adjustments only resulted in a total snow accumulation forecast of up to one half inch, highest in Divide County. At this point, the worst-case scenario appears to be around 2 inches of very wet, slushy snow. But to reemphasize, that is not the most likely outcome at this time. UPDATE Issued at 635 PM CST Mon Mar 8 2021 The main forecast consideration for the next 24 hours is evaluating the potential for a brief mesoscale banded snow event in far northwest North Dakota Tuesday morning. The 18Z NAM/NAMNest and 21Z RAP have arrived with a stripe of around 0.25" QPF across far northwest North Dakota, mostly falling from mid to late morning. This is quite the dramatic increase from the 12Z model suite, which averaged little to no QPF across the same area. Examination of dynamic and thermodynamic fields in guidance shows the potential for a band of heavy snow is certainly greater than zero. Several factors that could be present include left exit region jet dynamics, strong Q-vector convergence, steep lapse rates within the DGZ, strong mid level frontogenesis, and EPV near zero. However, not every model core contains all these features in the same place at the same time. For this update, we made some slight increases to PoPs and QPF across the far northwest, but this really does not change the overall messaging at this time. We will wait to evaluate the 00Z guidance and also see if this trend continues in hourly-updating guidance before making more drastic changes to the forecast. Even if a band of heavy snow does materialize, very low snow-to-liquid ratios (around 8:1 at most) should keep snow rates and amounts lower than would be expected for a typical banded snow event. && .SHORT TERM...(This evening through Tuesday) Issued at 222 PM CST Mon Mar 8 2021 Current surface analysis places ridge over the upper midwest with low over the Wyoming Bighorn Mountains. Upper level analysis places ridge over the northern plains into the midwest, with trough over the west coast. A variety of modest disturbances noted in the flow ahead of aforementioned trough. Quiet weather with some passing clouds continue here under the ridge, with very warm temperatures running 20 to 30 degrees above average. Bismarck, Jamestown, and now possibly Minot have already eclipsed their record highs for the day. For tonight, ridge axis pushes to the east with southwest flow setting up over our area. A fast moving short wave sliding through the flow makes its approach overnight, while aforementioned surface low ejects northeast, passing over central North Dakota near daybreak. Cooler air starts pulling in behind the low late tonight. Precipitation develops north and west of the low mainly out of our area, though a little bit may work its way into northern locations. On Tuesday, surface low pushes to the northeast through the day, sliding over the Minnesota/Ontario border around sunset. As the cold front behind the low swings southerly, cooler air pushes into our area. This will lead to quite a temperature gradient, with highs around 40 over the northwest and around 60 over the James River Valley. High temperature forecast is a bit tricky as it depends on the timing of the front and cooler air pushing in. Modest chances for light rain/snow remain over northern areas through the day, diminishing in the evening. .LONG TERM...(Wednesday through Monday) Issued at 222 PM CST Mon Mar 8 2021 On Wednesday a secondary low passes through the central plains, but will be far enough south to keep most precipitation out of our area. With that said, a little could sneak its way into our southern areas including the James River Valley. Thereafter, a dry forecast is on tap. Temperatures will be near to a bit above average. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 635 PM CST Mon Mar 8 2021 VFR conditions are expected across southern North Dakota through the forecast period. For northern North Dakota, ceilings are expected to lower to MVFR Tuesday morning. Some rain or snow is also possible across northern North Dakota Tuesday morning and afternoon, especially at KXWA. Southeasterly winds this evening will eventually transition to west-northwest by Tuesday afternoon as a center of low pressure and cold front move across the state. Winds speeds will increase to 15-20 kts Tuesday afternoon, with gusts near 30kts. A few hours of low level wind shear concerns are expected at KBIS and KJMS late tonight. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Hollan SHORT TERM...JJS LONG TERM...JJS AVIATION...Hollan
Area Forecast Discussion...Updated
National Weather Service Billings MT
901 PM MST Mon Mar 8 2021 .UPDATE... Heights were lowering as shortwave trough advances through the area from the west. This was dragging a cold front across western and central zones this evening, with areas of light precipitation developing behind the frontal passage. Stronger forcing was clearly northwest of the area, and for the most part, the strongest forcing will stay north. That being said, frontogenesis will create enough lift for likely PoPs west of Billings tonight. Not expecting a great deal of QPF, as low levels were still on the dry side, but the GFS/ECMWF/RAP were all pointing to an area of light snow developing this evening and swinging east across the central zones, into parts of the southeast. The HRRR was the least ambitious of the models. Raised PoPs tonight and Tuesday morning to account for this. TWH && .DISCUSSION... Rest of Today through Wednesday Night... Benign weather with east winds keeping temperatures around a modest upper 40s to low 50s will persist through the afternoon. Upslope flow and weak mid-level moisture will still allow a very small chance for snow showers to occur in the foothills west of Billings this afternoon, but for now it continues to occur as virga. Tonight, a cold front will swing across eastern Montana, bringing with it a few inches of snow to the mountains, especially on south to west facing slopes, and a small chance for light snow across south- central Montana. For the lower elevations, no major accumulations are expected, amounts will generally be under an inch if snow even occurs in the first place. Despite the cold front passing through, low will stay similar to last night and only get down to the upper 20s. Northwest to downslope flow persists throughout Tuesday as a surface low moves east across the Dakotas. Good mixing looks to occur to mix down winds that look to gust 30-35 mph across much of southeast Montana, and light snow will continue to occur in the mountains. Tuesday night through Wednesday, a shortwave moving through Wyoming will bring more snow to the mountains, especially the Bighorns. The bighorns look to get 3-6 inches throughout the day, with maybe a couple inches in the foothills in far southern Sheridan County. Most snow should be retreating from the area throughout the afternoon. Vertz Thursday through Monday... Cyclonic flow over the region on Thursday will give way to a rex block by Friday, as ridging builds over the Northern Rockies, and a cut off low moves underneath into the four corners region. Cooler temps and showers over portions of the area on Thursday will be followed by above normal temperatures and drier conditions for Friday through the weekend. More unsettled weather is possible for early next week with the cut off low lifting off to the north and east, opening the door for additional weather systems to move through the region. High temperatures on Thursday are forecast to range from the upper 30s to 40s, warming into the 40s and 50s Friday through Sunday. 30s and 40s for Highs are possible early next week. Low temperatures in the 20s can be expected most nights through the extended. STP && .AVIATION... Cold front will push E through SE MT and N central WY overnight, ushering in northerly surface winds and areas of snow. The snow will affect areas from KMLS to Lodge Grass W, as well as the NE Bighorn Mountains. Expect MVFR conditions in the snow with localized lower conditions possible. The western mountains will be obscured. The snow will continue Tuesday morning, but will taper off to rain and snow over the mountains and foothills in the afternoon. Arthur && .PRELIMINARY POINT TEMP/POPS... Tue Wed Thu Fri Sat Sun Mon ----------------------------------------------------------- BIL 031/049 028/046 026/045 026/049 027/052 030/057 029/046 43/S 12/S 11/U 11/U 00/U 01/U 12/S LVM 032/043 026/040 022/042 023/044 023/048 028/053 028/043 63/S 21/B 11/U 10/U 00/U 01/U 12/S HDN 030/051 026/046 024/046 024/050 023/054 026/058 026/048 33/S 12/O 11/U 11/U 10/U 01/U 12/S MLS 032/047 024/045 023/043 021/048 023/051 025/054 025/043 22/S 01/B 00/U 00/U 00/U 00/U 11/B 4BQ 032/049 026/043 025/045 023/048 024/050 025/052 025/044 11/N 13/S 00/B 00/U 00/U 00/U 11/B BHK 030/047 022/041 022/043 018/046 020/048 023/051 021/040 11/N 01/E 00/B 00/U 00/U 00/U 11/B SHR 027/048 024/038 019/042 018/045 020/047 021/051 023/044 12/O 56/S 21/B 11/U 11/U 11/U 12/S && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service Grand Rapids MI
1006 PM EST Mon Mar 8 2021 LATEST UPDATE... Update .SYNOPSIS... Issued at 221 PM EST Mon Mar 8 2021 - Freezing fog risk tonight to Tue AM - Rising rivers into the weekend - Gusty winds especially Wed night to Thu && .UPDATE... Issued at 1006 PM EST Mon Mar 8 2021 I believe there is still the threat of some patchy fog, mostly north of I-96 but I do not believe widespread dense fog is likely. Only the NAMnest is showing fog and the 00z run is showing less. The RAP and HRRR models do on show much fog, expect near Saginaw Bay. Typically to get dense fog a would want to see significantly more moist are moving over the shallow layer of cold air. Tonight while we do have a front that is stalled just north of I-96 the air south of the front is not all that moist. So the bottom line is patchy fog. I see no need for headlines at this time. && .DISCUSSION...(This evening through next Monday) Issued at 221 PM EST Mon Mar 8 2021 - Freezing fog risk tonight to Tue AM A weakening cold front will drop down from the northwest tonight and dissipate over the region. As winds taper off and temperatures cool down a risk for fog/freezing fog could develop. Several models including the NAM show a sharp increase in the RH values after midnight. Other models like the HRRR do not show much at all. With temperatures likely to fall below freezing especially northeast parts of the CWA...we will carry a local freezing fog risk. We are not confident enough to go with a headline at this time given the spread in the models. - Rising rivers into the weekend The combination of an inch or so of rain and melting snow is forecast to generate rising rivers. At this time this would generate only local minor issues if any on smaller streams and creeks. The main concern would be if end up with 2 or more inches of rain. While not the most likely is something we will need to monitor closely. We could end up with issues on the mainstem rivers if basin average amounts start going over 2 inches. - Gusty winds especially Wed night to Thu A stronger low level jet moves in later Wednesday into Thursday. Winds at 850 mb rise into the 40 to 50 knot range. It is not expected to mix to that depth then...but gusts in the 30 to 35 knot range look likely. This would be enough to cause isolated power outages. If mixing heights end up deeper we could see higher winds. For now we will continue to highlight the potential in the HWO and social media posts. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 631 PM EST Mon Mar 8 2021 Gusty winds this evening will subside quickly as the sun sets. A weak cold front comes through this evening too and that will help to diminish the winds. There is some question about fog toward morning. With the weak front having come through we will be in slightly cooler air and toward morning the front will head back toward us as a warm front. However the air heading into this area is not overly moist at this point. So, I do not think we will see a widespread dense fog event. Seems Lansing has the highest risk bases on it being the deepest into the colder air at sunrise. Also there is some suggestion fog from Saginaw Bay may advect in at low levels. Whatever fog does develop it will be shallow and should mix out quickly. Tuesday for the most part should be a day with only high clouds (those will be thin) and winds around 10 knots from the southwest at the surface. && .MARINE... Issued at 221 PM EST Mon Mar 8 2021 While a stronger low level jet moves Wednesday night into Thursday...the limited mixing height is expected to keep the winds under gale criteria. We will likely need another small craft advisory then. We will likely issue one later tonight or on Tuesday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...WDM SYNOPSIS...MJS DISCUSSION...MJS AVIATION...WDM MARINE...MJS
Area Forecast Discussion
National Weather Service Northern Indiana
631 PM EST Mon Mar 8 2021 .SYNOPSIS... Issued at 228 PM EST Mon Mar 8 2021 Afternoon highs in the low to mid 60s and lows in the 40s will be the theme into mid week before a cold front arrives, bringing shower chances to the area by late Wednesday night into Thursday night. Breezy conditions are expected into Tuesday with stronger wind gusts possible Wednesday afternoon in advance of the cold front. && .SHORT TERM...(This Evening through Wednesday) Issued at 228 PM EST Mon Mar 8 2021 Plenty of sunshine is allowing well mixed low levels, resulting in temperatures well in the 60s and some wind gusts in the 25 mph or so range. A weak disturbance was stirring up some mid clouds but these should quickly dissipate into the evening. Expecting a carbon copy of today in terms of temps and winds on Tuesday. Some models are giving some increased mid/high cloud cover once again. Bit skeptical on total sky cover being much more than 50% so some minor changes have been made. Clouds do look to become more of a factor on Weds as low level moisture begins to increase. Have left the mostly cloudy skies in for now. Increasing PWATs/Mixing ratios will be well underway into Weds afternoon, but lack of pronounced trigger suggests limited (if any) threat for some shower activity until the start of the long term period. With regards to afternoon dewpoints/humidity values, overall consensus was decent potential for mixing of much lower dewpoints that NBM and other models suggest. Have done some blending between current grids and RAP with HRRR most aggressive (dewpoints in the 20s in some areas). Last but not least, wind gusts of 25 to 30 mph even a bit higher in spots today) will likely occur again Tuesday afternoon with stronger gusts to 40 mph Wednesday afternoon. && .LONG TERM...(Wednesday Night through Monday) Issued at 228 PM EST Mon Mar 8 2021 Large cut off upper low will remain across the SW US, with a perturbed SW flow maintaining itself for several days. Impacts to our area remain greatest Thursday into Thursday night as baroclinic zone will approach and edge slowly SE. Some models are not overly impressed with QPF potential while others are much more aggressive. Blend of models lowered pops once again, but have held with previous forecast with high likely to cat pops Thursday into Thursday night. QPF did come up somewhat with overall rainfall now between 1 and 1.5 inches, with some areas possibly seeing a bit more. Some hydro concerns could occur (action to minor flood stage on rivers and ponding of water in low areas). I do have some concerns with those models showing less QPF as best dynamics will be well removed from the area and could limit overall QPF/precip coverage. Have continued to keep any mention of thunder out as best chances seem to remain west of us Weds night and south into Thurs. EC more aggressive on pushing front south of the area Friday into the weekend with GFS remaining a bit further north. Given the proximity of the front and impacts of each wave in question on the position have left in slgt chc to chc pops across the south into Sunday. The main upper low will finally begin moving east and then get a huge nudge north as strong ridge over the SE states refused to budge. This may send a swath of rainfall to the area late in the period, bit a lt of the dynamics will be shifting west so not sure what if any impacts it will have here. Plenty of time to watch evolution of this feature. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening) Issued at 624 PM EST Mon Mar 8 2021 VFR conditions to persist once again this forecast cycle with wind gusts once again Tuesday afternoon as the main concern. Gusty winds with deep mixing earlier this afternoon will quickly diminish this evening as low level decoupling occurs. Winds should diminish into the 5 to 10 knot range over the next hour or two as this occurs. A very weak cold front dropping across the southern Great Lakes has resulted in a wind shift to west- northwest at KSBN. This front will make little if any additional progress to the south which will keep a weak southwesterly gradient in place tonight. After sfc ridge axis passes across the Great Lakes tonight, a fairly strong gradient will set up again on Tuesday with another good mixing day. Expecting wind gusts to be slightly lower than today, generally in the 20 to 25 knot range for Tuesday afternoon. A band of mid level clouds will drop southeast across northern Indiana this evening, and will be replaced by mainly sct-bkn high clouds through remainder of the period. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...Fisher SHORT TERM...Fisher LONG TERM...Fisher AVIATION...Marsili Visit us at Follow us on Facebook...Twitter...and YouTube at:
Area Forecast Discussion
National Weather Service Marquette MI
949 PM EST Mon Mar 8 2021 .SHORT TERM...(This evening through Tuesday) Issued at 258 PM EST MON MAR 8 2021 Current RAP analysis and GOES WV imagery show a shortwave that was responsible for the clouds, breezy winds, and very light pcpn yesterday is moving off to the northeast towards the James Bay with high pressure taking control over Upper Michigan today. As the high moves overhead, stubborn clouds that were around the north and ease will clear out except for the far east around Newberry and the Mackinaw Straits. Otherwise, expect partly to mostly sunny skies for the afternoon and evening. With the clearing and light winds tonight, areas of patchy fog are possible tonight with more moisture in air as dewpoints from the afternoon will be in the upper 20s to low 30s. Clouds will slowly begin to filter back in early Tuesday, continuing through the day as a sfc low will track up through the northern plains with the high shifting slightly east towards New England. This will result in tightening pressure gradient again, bringing breezy south to southeast winds for the afternoon and evening Tuesday. Could see higher gusts along the Lake Superior shoreline in the downsloping areas. Next chance of pcpn will come late Tuesday into Wednesday ahead of next system. Temperature will be once again unseasonably mild for this time of year as our average high is only 32. Highs this afternoon will be in the 40s to low 50s across the south along the WI border. Lows tonight will mostly in the 20s with some upper teens over the traditional cool spots in the interior west. Tomorrow will be slightly warmer with more waa moving in with breezy southerly winds across the area with mid to upper 40s for the east with the cooler air from Lake Michigan but 50s are likely across the west half and maybe even a 60 along the WI border. .LONG TERM...(Tuesday night through Monday) Issued at 330 PM EST MON MAR 8 2021 A warm and mild night looks to still be on track Wednesday night as the region continues to find itself under the influence of an unseasonably warm and moistening airmass. Shortwave and surface low passing just north of the lake will push northeast, resulting in the gradual reduction of the pressure gradient across the area. Winds could still be a little gusty across the highlands of Marquette and Baraga counties, as well as in the east through the early morning hours. Where winds remain lighter through the night, expecting areas of fog developing given the likely ripe snow and warmer/moist airmass, particularly along the WI/MI state line and south central. The fog and warmer airmass will really limit how low temps get, and I`m generally expecting widespread low 40s across the region. Attention then turns upstream to a low ejecting out of the Plains early Wednesday. Models have been consistent with this system tracking northeast into the Upper Great Lakes, with moderate rain overspreading the area by Wednesday afternoon and persisting into the overnight hours. From there the lack of a detailed consensus raises a lot of questions. As with the previous forecast package, there still seems to be two camps on where the system will track and thus, where the cold air on system`s west/northwestern side will be. The options appear to be the western UKMET/Euro solutions and then the more eastern GFS/NAM/Canadian solutions. The western solutions keep the cold air in Minnesota as the low scoots through western Lake Superior. Its also noteworthy that the UKMET trended further west between the 0z and 12z runs. This presents mainly an all rain forecast due to the influence of the warmer airmass. The eastern solutions bring the low somewhere between the central or southern UP and Sault Ste. Marie. These have been consistent also cooling at the surface which would allow rain to change to freezing rain before the column cools further and transitions to snow on the western side of the low. Like yesterday`s guidance suite, some are hitting the freezing rain hard. Given the uncertainty in the position of the system and subsequent atmospheric variables, I`m still skeptical where this feature would end up. I`m even more skeptical of the there being significant impacts if it does materialize given the expected antecedent conditions that would limit freezing to surfaces. On Thursday, a brief area of high pressure is expected to build in behind this departing system. This ridge should bring the region mostly dry conditions Thursday afternoon and overnight into Friday morning. The colder air behind this system will help cool temps a little on Thursday. At the moment, low-mid 40s are expected. By Lake Superior and in the Keweenaw I expect it to be cooler, with near 40s and mid 30s, respectfully. By Friday, CAA will increase behind a weak cold front, bringing more seasonable temps. Most of the region should see highs in the 30s to near 40F south-central. Along this boundary, some light snow showers may move through the region, but soundings suggest an inverted v. So any accumulation would likely be hard to come by. The weekend looks dry, as mid-upper level ridging extending from the Gulf gradually shifts east through the region. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday evening) Issued at 948 PM EST MON MAR 8 2021 VFR conditions are expected for all sites until Tue evening when MVFR cigs move in. Some LLWS should work from west-to-east Tue, with KIWD seeing LLWS starting in the morning, KCMX seeing LLWS starting in the early afternoon, and KSAW seeing LLWS starting in the late afternoon. This LLWS, associated with a low pressure passing to our west, should continue to and past the end of the TAF period as another low pressure approaches the area from the southwest. The wind will get gusty at all sites on Tue as well. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 258 PM EST MON MAR 8 2021 Winds have been slow to ease as the shortwave from this morning is slowly moving away. Winds will fall below 20 knots tonight into Tuesday before turning south to southeast Tuesday afternoon and increasing to 20-30 knots over the central and eastern parts of the lake with a few gale force gusts to 35 knots possible. Winds will be at or below 20 knots Wednesday morning and becoming northerly. A cold front will cross the lake on Friday, increasing to 15-25 knots with the potential for gales as well. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JH LONG TERM...JP AVIATION...07 MARINE...JH