Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/02/25


Area Forecast Discussion
National Weather Service La Crosse WI
552 PM CST Wed Jan 1 2025 .KEY MESSAGES... - Occasional flurries continue. Quick hitting snow event for Thursday mostly tracking south of the forecast area. 01.00z to 01.12z HREF trending farther south; 0% to 10% probability of 0.1" or more in northeast IA/southern WI. - Uncertainty in snow chances remain Sunday into Monday. Ensembles continue to depict a southerly track, keeping the highest snow chances to the south, but there remains the potential (10% to 30%) for snow south of I-94. && .DISCUSSION... Issued at 229 PM CST Wed Jan 1 2025 Overview: The latest water vapor satellite imagery and 500mb heights show a broad trough over the central and eastern U.S. with northwest flow over the western U.S. A couple of embedded shortwave troughs were passing through the local area this morning with a quick-moving wave over the Pacific Northwest heading toward the Plains. 850mb temperatures at 12Z this New Year`s Day were in the -12--13.5 deg C range with scattered flurries/small snow pellets/balls. Latest visible satellite imagery showed some breaks in the clouds over parts of Iowa with considerable clouds elsewhere. At 19Z, winds were brisk from the northwest 5 to 20 mph with some gusts 20 to 30 mph. The 19Z WSR-88D mosaic and observations were picking up on areas of flurries across the region with some periodic visibility reductions. Occasional flurries continue. Quick-hitting snow event for Thursday mostly tracking south of the forecast area. 01.00Z to 01.12Z HREF trends farther south An embedded shortwave over northern Wisconsin continues to move through the region today with continued cold air advection, variable clouds and occasional flurries. Where the clouds linger, could also see some occasional flurries into the overnight hours. Lows are forecast to drop back into the teens, however due to the decreasing winds, should a pocket of clearing/thinning occur, some readings could drop into the single digits (01.12Z HREF 10 to 30% probability). The next ripple over the Northern Rockies is forecast to quickly push southeast into Iowa, with another weaker ripple farther north across the U.P. The trends from the 01.00Z HRRR and RAP have both shifted farther south with 01.12Z HRRR and 01.15Z RAP. The 1" per hour rates from 00Z to 12Z have also lessened in DMX`s area. The latest SREF does have some low probabilities of 100mb dendritic growth zone depths near our southern forecast area toward DBQ, but this may too shift south in coming runs. For now, with the increased cloud cover and steep lapse rates, cannot rule out some flurries, but organized snow appears to be tracking south of the area. Will continue to monitor the trends over the next 12 to 24 hours should there be any minor ripples or better RH that is not being picked up for Thursday. Uncertainty in Snow Chances Sunday into Monday The 01.00z WPC cluster analysis continues to indicate good agreement in the expected development of an upper/surface wave across the central United States as 80% of the ensemble members depict this solution. A lot of uncertainty regarding the impacts of this system across our area remains, mainly associated with variations in the timing/location of the aforementioned features. The 01.12z GEFS/GEPS/EPS continue to show increased agreement regarding the axis of highest precipitation/snowfall across Missouri, Illinois, and Indiana. It`s still too early to really begin hammering out precipitation/snowfall amounts across our area, but there is a high confidence that anything that falls will fall as snow. The 01.12z LREF soundings indicate a fairly stout surface-10kft dry layer over our area, which would make it challenging for dendrite formation and for snow to reach the ground. It is important to note that the spread in the dewpoint profile within this layer is very high, upwards of 20C between the 25th and 75th percentiles at some levels, so depending on the track this wave takes would be very influential to the atmospheric profile and to the outcome of this system in our area. There still remains chances for at least some precipitation across our area though, with the 01.13z NBM continuing to suggest 10-30% probabilities, mainly south of I-94. Overall, it seems as though our area will be spared from the brunt of this system based upon the latest model runs, but there are still plenty of questions regarding the details of the event that likely won`t be answered until the upper wave moves onto the west coast of the United States later this week. Otherwise, temperatures remain below freezing into early next week. There is some increased spread in the 25th and 75th percentiles in the GEFS/EPS by Monday associated with the uncertainty with the previously discussed system, but highs in the teens to mid 20s across the region are expected. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 552 PM CST Wed Jan 1 2025 Still seeing primarily MVFR cigs across the area local area this evening, with light snow/flurries being reported at various sites. Satellite imagery shows the western edge of these MVFR cigs slowly moving east/southeast across western and central MN. Based on these trends along with model guidance, have leaned optimistic towards eventual VFR conditions. However, seeing some indication in a couple hi-res forecast soundings for potential redevelopment of MVFR cigs, so will be monitoring these trends for any needed adjustments. Otherwise, west/northwest winds remain through the period, with some potential for additional flurries for a time Thursday. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Falkinham/Zapotocny AVIATION...EMS
Area Forecast Discussion
National Weather Service Boston/Norton MA
1005 PM EST Wed Jan 1 2025 .SYNOPSIS... Some showers fill back in briefly this evening as low pressure heads into northern New England. Strong and possibly damaging winds are expected Thursday as colder air works into the region.Dry conditions with below normal temperatures expected Friday through the weekend. A system should track to our south early next week, although there is a chance it brushes southern MA, CT, RI bringing light snowfall. && .NEAR TERM /THROUGH THURSDAY/... Made some more tweaks to the forecast this evening. Main changes were to precipitation timing as it moves offshore. Last few runs of the HRRR looked quite reasonable. While the precipitation across the coastal plain should be offshore by 1 AM, still expecting some lingering snow towards the Berkshires. Adjusted temperatures to reflect observed trends as well. Gave some consideration to a short-fuse Winter Weather Advisory. Thinking there will be a few communities, namely Rowe and Monroe, and perhaps Charlemont, that could see a few inches of snowfall by daybreak. However, that is not enough area to justify a Winter Weather Advisory for all of western Franklin County. The majority of that area is expected to see snowfall of 1 inch or less, with locally higher amounts up to 5 inches towards the high elevations along the VT/MA border. 8:30 PM Update: Radar shows areas of light to moderate rain moving across east and southeast MA with light snow over the Berkshires. Made some minor edits to the precip probabilities to account for recent trends. Overall, precipitation over east MA should exit to the east with dry conditions overnight. Gusty conditions will continue to settle in tonight. Key Messages... * Strong and possibly damaging winds Wednesday night and Thursday. The backside of the exiting low brings with it increasing cold advection this evening and overnight. Given the lingering shortwave energy overhead, another brief round of low elevation rain/high elevation snow showers are possible briefly this evening. While the rain showers should end rather quickly, upslope enhancement helps snow continue for the highest elevations of the Berkshires where a coating to a few inches are most likely; several inches of snow are possible in the terrain immediately along the MA/VT border. While cold advection brings dropping temperatures it also serves to steepen low level lapse rates, allowing for better mixing down of a robust 45-55 kt 850 mb LLJ. As we begin to tap into the stronger winds aloft, we may see wind gusts as strong as 45 mph in the high terrain and over the islands overnight. The peak of the winds for all of SNE, however, comes Thursday, as a warming surface promotes better mixing down from the top of the mixed layer. A Wind Advisory is in effect for all of southern New England where gusts are generally expected to be 45-55 mph. However, isolated stronger gusts are possible, up to 60 mph in spots, especially in the highest elevations. Temperature-wise, cold advection will be offset a bit by downslope warming on west winds for areas along the coast. Highs should be in the low to mid 40s along the coast, 30s inland. && .SHORT TERM /THURSDAY NIGHT/... Key Messages... * Winds diminishing but remaining breezy overnight. The low pressure over Nova Scotia is slow to exit further northwest, so while the core of the jet shifts east and the pressure gradient weakens ever so slightly, winds will remain elevated overnight, gusting 25 to 35 mph for most, though some stronger gusts are possible in the highest elevations. Temperatures dip into the mid to upper 20s, but wind chills will be in the teens. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Key Messages: * Cooler with below normal temperatures arriving by the weekend continuing through next week. * Low chance for a system to graze southern MA, RI, CT early next week bringing light snowfall. An upper level low positions over Quebec Friday through the weekend with a broad upper trough settling southward across the northeast by Sun. There is a solid consensus among ensemble guidance for an anomalously cooler airmass to accompany the trough bringing below normal temperatures to the region. Highs range in the mid to upper 30s Friday. We tap more into the cooler part of the airmass Sat/Sun with northwest flow aloft. High temperatures will likely struggle to get above freezing Saturday with Sunday being a few degrees cooler. The nights will be chilly with temperatures dropping into the teens/low 20s. This period will stay mainly dry with little moisture available in the flow. Can`t rule out some ocean effect showers across the Cape and Islands over the weekend. Next Week: For early next week, models continue to show a system that moves across the central U.S. toward the east coast. Ensemble means track this system to our south across the mid-atlantic coastal areas. There are a smaller chunk of ensemble members (mainly in the ECMWF) that show the system track north enough to brush southern MA, CT, and RI. This puts a low chance (< 25%) for light snow showers in those areas. There is some uncertainty in timing, but these chances should fall in the Monday-early Tuesday timeframe. Upper level troughing stays put across the region next week which will continue the pattern of high temperatures around 5-10 degrees below normal in the upper 20s to low 30s. There is a chance for ocean effect showers across the Cape/Islands Tues/Weds otherwise mainly dry conditions through late week. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Forecast Confidence Levels: Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 03z TAFs: Moderate confidence due to timing of trends. Ceilings have improved early this evening with VFR at most terminals as of 00z. One last round of showers moves through this evening which could cause brief MVFR ceilings. Dry, VFR conditions after 03z. VFR Thu and Thu night. W/SW later become more W/NW tonight. Gusts 20-30kt persist tonight, with gusts reaching 40-50kt Thu. Thu night W winds diminish but remain gusty. KBOS TAF...High confidence in TAF. KBDL TAF...High confidence in TAF. Outlook /Thursday through Sunday/ Friday through Friday Night: VFR. Breezy. Saturday: VFR. Windy with local gusts up to 30 kt. Saturday Night through Sunday Night: VFR. Breezy. Monday: VFR. Breezy. Slight chance SN. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High- greater than 60 percent. High confidence through the end of the week. Maintaining Gale Warnings on all waters as strongest winds begin this evening and peak Thu before subsiding later Thu night and Fri. It`s possible we see some gusts reach Storm force (48kt) but we don`t have enough confidence that those gusts will occur over a large area or for more than a couple of hours Thu. Nonetheless, conditions will deteriorate quickly this evening as winds and seas increase. Thursday night winds and seas will begin to slowly diminish. Outlook /Friday through Monday/... Friday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 10 ft. Friday Night: Winds less than 25 kt. Seas up to 5 ft. Saturday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft. Saturday Night: Strong winds with gusts up to 30 kt. Areas of rough seas. Chance of freezing spray, slight chance of snow. Sunday: Strong winds with gusts up to 30 kt. Areas of rough seas. Sunday Night: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Chance of freezing spray. Monday: Winds less than 25 kt. Local rough seas. Slight chance of snow. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Wind Advisory until 10 PM EST Thursday for CTZ002>004. MA...Wind Advisory until 10 PM EST Thursday for MAZ002>024-026. RI...Wind Advisory until 10 PM EST Thursday for RIZ001>008. MARINE...Gale Warning until 3 AM EST Friday for ANZ230>237-251. Gale Warning until 7 AM EST Friday for ANZ250-254>256. && $$ SYNOPSIS...BW/Mensch NEAR TERM...Belk/BW/Mensch SHORT TERM...BW LONG TERM...Mensch AVIATION...Belk/BW/Mensch MARINE...BW/Mensch
Area Forecast Discussion
National Weather Service Green Bay WI
955 PM CST Wed Jan 1 2025 Updated aviation portion for 06Z TAF issuance .KEY MESSAGES... - Light snow and flurries will continue at times through Thursday afternoon across the region. A dusting to a couple tenths of accumulations are possible. - Lake effect snow is expected in far northern Wisconsin Thursday night through Friday that could produce an inch or two of accumulations. - Colder temperatures have arrived to kick off the New Year. Sub- zero wind chills will be likely during the overnight periods Thursday through Sunday across most of the forecast area. && .DISCUSSION... Issued at 211 PM CST Wed Jan 1 2025 Short Term...Tonight and Thursday The latest RAP analysis and satellite/radar imagery show a longwave trough extending southeast over the Great Lakes early this afternoon. After one ambitious shortwave upwards of 1 inch over east-central and far northeast WI earlier today, another shortwave moving through the trough is tracking over northern WI. While it appears more dynamic, this shortwave will bring widespread light snow and flurries to areas north of Hwy 29 and Door county through early this evening. Additional flurries are moving east across southwest Wisconsin as well. Don`t see much more than a couple tenths of accumulations. Otherwise, cold advection continues within northwest flow aloft. Widespread low clouds prevail upstream with areas of flurries. Forecast challenges mainly include light snow and cloud trends. Snow and Clouds: The shortwave over northern WI will exit into northern Lake Michigan by mid to late evening. Within cyclonic flow, relative humidity progs and upstream obs suggest that moisture will likely be sufficient for occasional flurries to occur over northern WI for much of the night and Thursday. As another shortwave approaches northern Wisconsin on Thursday afternoon, light snow could become more widespread based on humidity progs. Minor accumulations to a half inch look possible. Farther south, flurries will likely persist at times through the evening. Then some breaks in the overcast are possible overnight and Thursday morning before clouds increase again on Thursday afternoon. Temperatures: Cold advection continues gradually through Thursday (and beyond). Highs ranging from the middle teens to middle 20s are forecast on Thursday afternoon. Long Term...Thursday Night Through Wednesday Focus for the extended revolves around a cooling trend through at least the middle of next week as a north/northwest flow regime ushers in a cold snap to start the new year. Precip chances look to be minimal, although aforementioned northwest flow and cold air advection should be enough to turn on the lake effect machine across northern Wisconsin Thursday evening through Saturday afternoon. Temperatures... A blocking high over Greenland paired with ridging over the Intermountain West will place most of the Midwest under persistent northwesterly flow through the middle of next week, bringing about the return of arctic air. 850 mb temperatures between -18 and -20C paired with large-scale subsidence from Canadian high pressure will result in weekend highs struggling to make it into the teens in north-central Wisconsin. Coldest period currently looks to be Friday night into Saturday morning when wind chills bottom out near -15C from central to north-central Wisconsin, locally colder in typical cold spots. However, current thinking is that we will manage to skirt just below cold weather headline criteria. Snow chances... Snow chances in the extended will mainly be limited to lake effect across the north given the lack of ice on Lake Superior. Lake surface to 850 mb delta Ts approaching 22C paired with a northwesterly wind component would favor decent snowfall amounts across far north-central Wisconsin during this time. However, anomalously cold 850 mb air will likely hinder dendritic growth and potential for accumulation. Dry air intrusion from Canadian high pressure will likewise be a hindrance to snowfall amounts. This being said, would not be surprised to see between one and two inches in the snowbelts through Saturday. Have boosted lake effect PoPs across the north through Saturday afternoon to reflect this. Track of the Sunday/Monday system has been trending further south with the most recent suite of model runs. Probabilities of receiving one inch of snowfall remain at a meager 5 to 10 percent, mainly along/south of the Highway 29 corridor. Suspect that the bulk of the precip will be shunted off to our south where strongest forcing is. && .AVIATION...for 06Z TAF Issuance Issued at 955 PM CST Wed Jan 1 2025 MVFR ceilings and occasional light snow or flurries will continue for most of the night, except there will be some clearing east of a IMT to MSN line late tonight and Thursday morning. Flight conditions should become VFR over all but far northcentral Wisconsin Thursday, though scattered snow showers are not out of the question. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....MPC/Goodin AVIATION.......RDM
Area Forecast Discussion
National Weather Service Northern Indiana
724 PM EST Wed Jan 1 2025 .KEY MESSAGES... - Light lake effect snow showers overnight, only very light accumulations and few if any weather or traffic related impacts. - Weak, fast moving system brings light snow Thursday night, mainly south of US-30 - Periods of lake effect snow showers into the weekend along with colder temperatures. - Uncertainty remains regarding potential winter weather impacts Sunday night into Monday. && .DISCUSSION... Issued at 259 PM EST Wed Jan 1 2025 Cold front and initial disturbance responsible for pockets of very light accumulations as well as lake enhanced snow showers was working east. Limited reports have been received, but based off webcams accumulations have generally a dusting to maybe a half inch. One more area of vorticity moves through into this evening to allow for a small window of renewed snow showers north of US 30 and greatest amounts US-6 north. Cooler temperatures and time of day may allow for a bit more accumulation that today, but overall should still average a half inch or less. Activity quickly ends overnight. A lull in the precip occurs with brief, weak ridging ahead of a fast moving wave set to bring another round of synoptic snowfall maybe as early as late Thursday afternoon, but best chances 00Z-09Z Fri. Confidence is highest in S/SW areas (along and south of US-30) for accumulating snow on the order of 1 to possibly 2 inches with the greatest chance for a bit of overachieving along/south of US-24. As the wave comes east it will be losing some of its definition but should still maintain enough energy. Models do vary on northward extent of measurable snowfall but many places should see at least a few snow flakes even towards the toll road. Lake effect will begin to kick in as the low is departing, but the most favorable conditions don`t arrive till after 16Z Fri when delta T`s peak near 20 C, equilibrium levels around 10 kft and 0-2 km ThetaE Lapse rates become slightly negative even well inland. Highest pops have been confined closer to the lake through 6Z Sat but may need to expand further SE in subsequent forecasts. Pockets of 1 to maybe 3 inches of snow are possibly, but given the multi cellular nature this is not expected to be widespread. Focus then shifts to the much discussed strong wave still over the Pacific, which approaches the western US coast by 18Z Fri (and finally get sampled by the upper air network). As it comes on shore the energy fractures somewhat, with the strongest element diving SE to the TX/OK Oklahoma panhandle by 6Z Sun, then NE into the Ohio Valley 24 hours later. While models do have some concensus on overall track of the sfc low over Kentucky by 6Z Mon the northward extent of the energy and moisture varies. Ensembles show a rather stout wall (gradient) of precip barely edging into our southern counties. Given still several days out and models expected to waffle until the system is better sampled, it is important not to key in on any particular solution at this point. In addition, while we trend colder (well below normal), highs may "bottom out" in the teens by the middle of next week which will still feel rather cold compared to the overall warm pattern in the past weeks. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 713 PM EST Wed Jan 1 2025 The cloud layer upstream was just deep enough to support flurries with the top of the cloud in the DGZ according to the latest HRRR BUFKIT soundings. Flurries should spread across northern Indiana overnight and especially the SBN terminals. Cloud bases should be MVFR and above 020. At this time it appears SBN will be just far enough south to be in the path of snow showers. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...Small Craft Advisory until 5 AM EST Thursday for LMZ043-046. && $$ DISCUSSION...Fisher AVIATION...Skipper
Area Forecast Discussion
National Weather Service North Platte NE
547 PM CST Wed Jan 1 2025 .KEY MESSAGES... - Tonight a slight chance for light snow across eastern portions of north central Nebraska with snowfall potential for a trace to a half inch. - Cold temperatures will persist Friday through Tuesday, with the coldest temperatures across central and eastern Nebraska. - An upper trough will cross the region Saturday into Sunday. This will bring the likelihood for light snow accumulations, especially east of Highway 83. && .SYNOPSIS... Issued at 313 PM CST Wed Jan 1 2025 A nice New Years Day, with 3pm CST temperatures from 45 at Ogallala, 43 at North Platte, and 36 at Valentine. O`Neill was coldest at 27 degrees where mixing and existing snow cover holding back temperatures. Beginning to see an increase in mid and high clouds across the west. && .SHORT TERM /THROUGH THURSDAY NIGHT/... Issued at 313 PM CST Wed Jan 1 2025 Tonight, a cold front will drop south overnight. The HRRR and RAP13 show fog development behind the front over the northwest and central Sandhills. And have included patchy fog late tonight through late Thursday morning. Stratus will also develop behind the front and persist through much of the day Thursday across the northeastern half of the forecast area with highs from 25 to 30. Thursday night, surface high pressure builds in with lows from 7 to 15 above. Added a mention of patchy fog across portions of the south where the HRRR and RAP13 show the best potential. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Issued at 313 PM CST Wed Jan 1 2025 Friday, arctic high pressure will extend from Saskatchewan Canada down through the Mid Missouri Valley. Flurries or a slight chance for light snow across Sheridan and Cherry County. The GFS bufkit sounding shows a nearly saturated layer from H85 through H5 and within the DGZ. Will see isentropic upglide increase through the day across the north central. Adjusted highs down slightly with the presence of arctic air and considerable cloudy skies and light easterly winds. Coldest in the upper teens far northeast. Friday night, chances for light snow and flurries will increase in the north central as isentropic upglide continues and saturation increases. The GFS, NAM and ECMWF all indicate light QPFs. At least a dusting of snow is probable at 50 to 60 percent near and north of of Highway 20. Lows from 5 to 15 above, coldest across the northeast. Saturday into Sunday an upper trough will cross the region bringing increased chances for light snow accumulations. On Saturday, the upper trough will move across the Intermountain West to eastern MT and CO by late afternoon. Have 20 to 50 POPs for light snow across all except the far southwest. Bufkit soundings show a dry layer from H75 to H5, though very saturated in the lowest levels. Though the current forecast is for light snow, could see a mixture of very light snow/freezing drizzle with the existence of the drier layer aloft and -5C to -9C from near surface to H75. Highs Saturday will be colder from the mid to upper 20s west and southwest to mid and upper teens northeast. Saturday night, surface low pressure will track from the Texas panhandle into eastern Oklahoma as the upper trough axis moves through the Central Plains. Soundings show deep saturation and POPS increasing to 50 to 70 percent. the main deformation zone will develop across central and eastern Kansas into southeast Nebraska and Missouri overnight, where the threat or freezing rain and snow will be greatest. Much colder air will keep the precipitation type as all snow across western and north central Nebraska. Snow chances continue Sunday morning, diminishing in the afternoon. NBM probabilities for a half inch or more snowfall in 24 hours is from 50 to 70 percent north of Highway 2. While snowfall total should be light, there is good likelihood that many locations will see some light snow with this event. Uncertainties on the strength and timing of this system continue to result in low confidence on how much snow is expected. Cold temperatures will persist Sunday into Tuesday in the teens and 20s as arctic high pressure persists across the region. A warmup expected next Wednesday as upper ridging begins to build in and 30s to low 40s may return to the west. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 545 PM CST Wed Jan 1 2025 Expect flight conditions will deteriorate overnight as low clouds and fog push down from the north behind a weak low moving off to the east. Any precipitation associated with the low is expected to have no impact on TAF sites but will monitor trends near KVTN to see is a mention of snow becomes necessary. By Midnight there is good consensus for low clouds/fog with up to a 90 percent chance for IFR conditions at KVTN to persist through mid morning Thursday, though the signal for low VSBY is not as strong. KLBF will be on the edge of the low clouds/fog so confidence is low for impacts at the airfield. Will stay prevailing VFR at KLBF and use a TEMPO to IFR for the time when sub-VFR conditions make their closest approach. Winds will generally be light at 10kt or less through the period. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Roberg/Viken SHORT TERM...Keck/Roberg LONG TERM...Keck/Roberg AVIATION...MBS
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
847 PM CST Wed Jan 1 2025 .KEY MESSAGES... - Accumulating snow Thursday afternoon and evening, primarily south of I-80 with an inch or two likely. - There is another chance for snow on Sunday/Monday, but confidence in specific details remains low at this time. && .UPDATE... Issued at 847 PM CST Wed Jan 1 2025 Going forecast tonight through Thursday remains on track with only minor adjustments needed. A broad upper trough continues to spiral over the Midwest and Great Lakes this evening with a couple of modest waves traversing across WI and Lower MI. While there have been some occasional flurries being observed across WI and northeast IA, the drier air over northern IL and northwest IN has prevented such activity from reaching the ground locally. That said, still cannot rule out a stray flurry through midnight for areas near the IL-WI line. Otherwise, expect mid-level stratus to remain overhead through the night which should help hold temperatures a few degrees warmer than originally thought. Overnight lows could still dip into the lower 20s in far northern IL tonight, but most other areas should see readings in the mid-20s to start our Thursday. The main forecast concern for Thursday continues to be the expectation for accumulating snow to develop with an upper-level shortwave trough and associated surface low. The latest guidance remains in very good agreement on the surface low tracking across central and north-central IL-IN Thursday afternoon which should focus the band of snow along the elevated frontal zone to the north of the lows center. While general consensus continues to show this band occurring along and south of Mendota, IL to Rensselaer, IN line; there has been a notable wiggle northward in some of the hi-res guidance (namely the RAP and HRRR) this evening. If this shift continues then the higher snow totals could reach the I-80 corridor with lesser amounts possibly extending as far north as I-88. Given that this trend is only being seen a few select models have opted to maintain the going forecast for now, but did broaden the northern extent of POPs in the forecast to hint at this trend. Regardless, accumulations with the peak of the snow band should top out in the 1-2 inch range though locally higher pockets upwards of 3 inches could occur especially near and west of I-39. That said, those in the aforementioned favored area should be prepared for some slippery travel Thursday afternoon and evening due to snow accumulating on roads and reduced visibilities. The snow is expected to taper from west to east between 9 PM and midnight Thursday with dry conditions expected for the rest of Thursday night. Yack && .DISCUSSION... Issued at 215 PM CST Wed Jan 1 2025 Through Thursday Night: Conditions are rather quiet out there this afternoon following a burst of some moderate snow this morning that managed to coat roads around the north and northwest suburbs. Area webcams show that the snow has melted off of the roads ridding concerns for slick travel, but a dusting remains on grassy surfaces. The low stratus and ongoing cold advection have kept temperatures from moving much during the day. Early this afternoon, temperatures are sitting in the upper 20s and lower 30s. The cold advection has also enabled us to regularly mix down gusts in the 20 to 25 mph range. Winds will gradually step down some, but remain breezy through tonight as mixing looks to continue. Additionally, a few flurries may get going this afternoon into this evening. Our radar is currently picking up on some light returns around the area, although nothing appears to be making it to the ground at the moment, at least as far as we can tell. This drier near-surface air may continue to be too much for any flurries aloft to survive their trip to the ground. Conditions will be cold tonight into tomorrow with lows progged in the lower and middle 20s and with wind chills in the teens and even single digits forecast near the IL/WI state line. Tonight, a low amplitude, low level shortwave will spin up off the lee of the Colorado Rockies and track eastward over the central Plains and then lower Midwest tomorrow into tomorrow night. This will bring us our next potential for accumulating snow beginning tomorrow afternoon. A region of efficient warm, moist upglide will develop out ahead and help to fuel the system. Guidance is also resolving appreciable forcing for ascent focused in the 800-600mb layer which includes through a nearly-saturated DGZ. Just beneath this better omega, an impressive low level f-gen circulation is expected to extend north and east from the low center, along the storm`s cold conveyor. While the snowfall should largely be on the lighter side, a rather narrow band of higher rates is anticipated near where this f-gen tracks. Guidance is in pleasantly good agreement on the behavior of this storm tomorrow and general distribution of the snow. The actual surface low will track across central IL during the latter part of the day. Nearly all deterministic guidance paints a narrow swath of higher totals somewhere between the I-80 corridor and our southern CWA border, so confidence is rather high that the southern half of the CWA is the area to watch for greatest impacts. Confidence could be higher in actual accumulations, but most guidance generally supports 1-2" in this corridor of higher totals. There is some support for less than an inch, but almost none for anything much greater than 2". Lesser accumulations up to several tenths are expected to spread north of I-80. However, a good chunk of our northern CWA will probably get away with little to no accumulation, particularly north of the I-90 corridor as well as in and around Chicago. Snow will begin moving in from the west during the early afternoon with the heaviest snow potential during the late afternoon and evening, meaning travel impacts will be possible for PM commuters. The snow will move away to the east by the end of the evening. We will continue on our cooling trend following this system, but discrepancies in snow cover is leading uncertainty regarding temperatures tomorrow night. The going forecast reads lows in the middle and upper teens accompanied by wind chills in the single digits to near zero into Friday morning. Doom Friday through Wednesday: Friday will be windy and cold with highs in the low to mid 20s and wind chills in the single digits. Guidance continues to suggest we will see a good deal of sunshine Friday. I`m always worried about stratus potential in cold air advection regimes this time of year, but struggling to find evidence to support beefing up sky cover for Friday with guidance unanimously showing mostly sunny skies. Saturday looks to be a carbon copy of Friday with just less wind and more moderate wind chills. Very little change in thinking for the system progged to affect the region late Sunday through early Monday. The 12z GFS/GEFS and ECMWF/EPS haven`t shown any appreciable trends with this system, other than more consolidation of individual ensemble members closer to their respective ensemble means. The consensus track of this system would continue to place the band of heaviest snow just south of our CWA, though with measurable snowfall still making it into at least our southern CWA. While there is a shrinking ensemble spread and pretty good run to run consistency, it is important to remember that we are still in the time frame of the forecast where substantial changes in the forecast track and intensity of this system could occur. So even though the brunt of the heaviest snow is progged to miss our CWA to the south, can`t rule out a northward or southward shift in the track in coming days, so stay tuned. One other wildcard to keep an eye in coming days is the potential for lake effect snow, possibly even into northeast IL. Who sees lake effect Sunday into Monday will depend on the exact track and strength of the sfc low and the positioning and strength of the sfc high, neither of which can be forecast with the degree of specificity needed to narrow down exactly where a lake effect potential could exist. Given the current expectations, there could be a window for some lake effect potential into northeast IL for a time before any lake effect shifts east into northwest Indiana. But stay tuned, a lot can change between now and then. Finally, slightly colder air will filter into the region later Monday into early Tuesday, but with this system not forecast to phase with the polar front jet, the initial push of cold air should be moderately cold. However, medium range guidance suggests that lurking a day or so behind this system will be an Arctic front and a more substantial push of Arctic air Tuesday night into Wednesday. The operational 12z ECMWF and GFS both have 850mb temps approaching -20C into the area with that cold push, but their respective ensembles both suggest that -20C is toward the 10th percentile, in other words toward the coldest end of the spectrum of guidance. Bottom line, it looks like a formidable push of Arctic air could arrive by the middle of next week, but the magnitude of the cold is still uncertain. How much, if any snow cover, that will be present over the area by then could also impact how much modification could take place to this air mass when it gets here. - Izzi && .AVIATION /00Z TAFS THROUGH 06Z THURSDAY/... Issued at 537 PM CST Wed Jan 1 2025 Forecast concerns include... Mvfr cigs tonight. Gusty westerly winds tonight. Chance of snow Thursday afternoon/evening. Cig trends tonight are a bit uncertain. They`ve lifted to near 3kft and also scattered out across parts of the area but another area of mvfr cigs across northeast IA and northwest IL may move across the terminals. Have opted to maintain mvfr cigs through the night with scattering possible Thursday morning but trends will need to be monitored. There also could be a few flurries tonight, if the mvfr cigs become prevailing. Westerly winds gusting into the lower/mid 20kt range will slowly diminish through the evening with gusts expected to end overnight. Westerly winds will continue into Thursday afternoon with speeds at 10kt or less. Directions may turn more to the northwest Thursday afternoon into Thursday evening. A clipper system will move across central IL Thursday afternoon and into central IN Thursday evening bringing a narrow swath of snow. There remains uncertainty as to how far north the northern edge of this snow will move and it will likely be near MDW/GYY and have added prob mention to both forecasts. Any slight jog north with this system would result in the need for prevailing snow mention with prob/tempo for lower conditions, including at ORD and changes with later forecasts are possible. For locations south of the terminals, ifr cigs/vis can be expected with this snow. cms && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...Small Craft Advisory until 9 PM CST this evening for the IL nearshore waters. Small Craft Advisory until 3 AM CST Thursday for the IN nearshore waters. && $$ Visit us at weather.gov/chicago
Area Forecast Discussion
National Weather Service Midland/Odessa TX
457 PM CST Wed Jan 1 2025 ...New AVIATION... .KEY MESSAGES... Updated at 457 PM CST Wed Jan 1 2025 - Continued chilly temperatures through this afternoon. Warming back above normal tomorrow and staying warmer into the weekend. - A weather system approaches late this weekend bringing much colder temperatures for early next week. - How cold it will get and whether or not our area sees any precipitation remains uncertain at this time. && .SHORT TERM... (This afternoon through Thursday night) Issued at 153 PM CST Wed Jan 1 2025 High temperatures continue to under-perform compared to the NBM even as NBM highs have trended lower in runs from the past 24 hours. However, compared to other models such as HRRR and GFS, NAM is running too cold northeast of Pecos River and Marfa Plateau. Have continued with the blend of HRRR, NAM12BC, and NBM10Pct, NBM25Pct, and NBM50Pct for highs today from morning update. Temperatures may not get out of the 40s in far northern portions of SE NM plains and northern Permian Basin where VIS/IR Satellite had shown lower clouds moving in and inhibiting solar heating. These lower clouds are beginning to dissipate and move back northeast, but we are still expecting highs in the upper 40s to lower 50s for most of the region northeast of Pecos River and mid 50s to lower 60s outside of mid to upper 60s along the Rio Grande. Highs below average expected today for the area, except for Marfa Plateau into Presidio Valley and Big Bend, where highs rise into the 60s and remain 5 to 10 degrees above average are forecast. Clouds begin to decrease this afternoon over northern portions of the area. Tonight, lows fall near or below freezing for most places outside of the higher elevations, Rio Grande basins, Stockton Plateau into southeast Permian Basin, and Terrell County. NBM lows Wednesday night have trended lower by a few degrees over lower elevations with better drainage flow. However, winds will be veering back to southerly, ending CAA. Coldest temperatures in the mid to upper 20s expected over SE NM plains into Upper Trans Pecos, as well as basins of Culberson County. Westerly downsloping winds developing by morning along with mostly sunny skies Thursday allow temperatures to rise to 12 to 14 degrees above average, mid to upper 60s, lower to mid 70s Rio Grande basins and Terrell County into Stockton Plateau and Reeves County Plains. NBM highs for Thursday have trended warmer by a few degrees, so confidence continues to be high for a warm day everywhere for tomorrow. Thursday night, lows warmer than Wednesday night are forecast, but a cold front moving in from the northeast drops temperatures down to near or below freezing for basins of Culberson County, Upper Trans Pecos into SE NM plains and most of Permian Basin, with lows in the mid to upper 20s over northernmost Lea County. Still no chances of rain indicated in grids even with this front, but precipitation chances may return for next week. Read the long term discussion for more. && .LONG TERM... (Friday through Tuesday) Issued at 153 PM CST Wed Jan 1 2025 The return of an active weather pattern in the long term forecast period results in much to discuss. The start of this forecast remains warm despite a weak cold front on Friday. This cold front will push through the region early Friday and result in cooler temperatures for areas north and east of the Pecos River during the afternoon. With that said, all remain above normal with temperatures primarily in the 60s. Southerly winds quickly return ahead of our next major weather system on Saturday. These southerly winds, combined with sunny skies, push temperatures well above normal into the upper 60s and 70s for many. Substantial change is anticipated to arrive beginning on Sunday. Our next upper-level trough in this progressive weather pattern will move over our region during the day on Sunday. Current ensemble trends are keeping a more progressive and further north track to this system. Regardless of the exact details, breezy west winds through the afternoon are likely to continue the run of above average temperatures in the 60s with some 70s. Cooler temperatures may be possible across our northern areas as a strong cold front begins to race south through the southern Great Plains behind the upper-level trough. At the current moment, model guidance keeps this front north of our area through peak heating, but a faster front would result in much cooler temperatures for Sunday afternoon for some should this trend materialize. Sunday night sees continued advection of the first true arctic airmass of the winter season for our area. The new week begins as a chilly first full week of January. Near to below freezing temperatures start the day on Monday for most north of the Davis Mountains with middle to upper 30s elsewhere. The colder temperatures should continue through Monday afternoon as most remain in the 50s. Everyone is likely to fall below freezing by Tuesday morning as this arctic airmass hangs on. Details beyond Tuesday morning remain a bit fuzzy. Our next weather system is expected to begin developing across the Great Basin. This system continues to dig towards northern Mexico by mid-week. The exact speed and strength of this weather system remains uncertain with an almost even split in ensemble and cluster guidance between a slower, deeper upper-level trough and a more progressive, weaker upper-level trough. Regardless of the exact details, confidence in two things is increasing, a reinforcing shot of cold air and perhaps a chance at precipitation. The current thinking is 40s for afternoon high temperatures and morning temperatures in the 20s. A chance of snow may be possible near the western higher elevations with the aid of upslope flow as well. This is subject to change as temperatures may end up even colder with more precipitation potential if a stronger trend with this weather system materializes. Either way, winter will finally make itself known to our region. -Chehak && .AVIATION... (00Z TAFS) Issued at 457 PM CST Wed Jan 1 2025 VFR conditions and light winds will continue the next 24 hours. && .PRELIMINARY POINT TEMPS/POPS... Big Spring 32 69 32 62 / 0 0 0 0 Carlsbad 28 66 33 61 / 0 0 0 0 Dryden 35 69 42 65 / 0 0 0 0 Fort Stockton 35 71 38 69 / 0 0 0 0 Guadalupe Pass 38 63 41 62 / 0 0 0 0 Hobbs 28 69 30 60 / 0 0 0 0 Marfa 33 71 37 69 / 0 0 0 0 Midland Intl Airport 33 69 33 63 / 0 0 0 0 Odessa 34 68 35 63 / 0 0 0 0 Wink 30 69 34 63 / 0 0 0 0 && .MAF WATCHES/WARNINGS/ADVISORIES... TX...None. NM...None. && $$ SHORT TERM...94 LONG TERM....91 AVIATION...10
Area Forecast Discussion
National Weather Service Marquette MI
630 PM EST Wed Jan 1 2025 .KEY MESSAGES... - Lake effect snow showers continue in the WNW wind snow belts. Occasionally heavier snowfall rates up to an inch per hour will be possible at times tonight through Thursday, particularly for Alger and Luce counties (20-30% chance). - A Winter Weather Advisory is in effect for Ontonagon and northern Houghton counties until 7pm EST this evening, and for Alger and Luce counties until 7pm EST Thursday. - Temperatures trend down this week with highs below normal for Friday and Saturday. Below normal temperatures anticipated for majority of days next week. - Accumulating lake effect snow will occur in the west to northwest wind snow belts into the weekend, leading to some areas of hazardous travel conditions at times. - With the colder conditions next week, lake effect snow will continue on most days, but there are no indications for any winter storms to impact Upper MI. - Northwest gales expected Friday and Saturday over central and eastern Lake Superior. && .SHORT TERM /THROUGH TONIGHT/... Issued at 255 PM EST Wed Jan 1 2025 Water vapor and RAP analyses show deepening low pressure over New England this afternoon, while ridging dominates the Plains. In between, the Great Lakes remain under chilly NW flow aloft. 850mb temperatures over the UP and Lake Superior are already analyzed at around -10 to -12C, and should continue to fall further to around - 14 to -16C through tonight. With lake surface temperatures generally around 4-6C, delta-Ts are sufficient for lake effect snow to persist across the WNW wind snow belts. Convergence across far western Lake Superior into the western UP, as well as into the eastern UP, should allow for occasionally heavier snowfall rates at times (HREF continues to favor around a 10% chance for up to 1in/hr through this evening). This could lead to reduced visibility at times through the evening commute, as well as another couple inches of snow by sunset in the heaviest of snow showers. Meanwhile, temperatures are peaking only as high as the lower/mid 20s in the western UP, but have been able to climb a couple degrees warmer in the east with many spots seeing highs around 30. WNW winds are gusty at times, manly closer to Lake Superior and across the Keweenaw, with gusts to around 20mph possible. As CAA continues tonight, more of the lowering DGZ becomes co- located with the lake-induced convective layer. This will result in increasing SLRs and perhaps an uptick in snowfall rates. Working against this, however: model soundings across the western UP show lowering inversion heights beneath a developing isothermal layer above 4kft. This could spell an end to the heavier snowfall rates in the western UP, so the winter weather advisory will be allowed to fall off then. Will note that accumulating lake effect snow will persist through Thursday and beyond, though travel impacts should be lessened. To the east, deeper mixing to around 10kft (depending on your model of choice) will keep the potential for heavier snowfall rates in the forecast the rest of the night for Alger and Luce counties. A general 1-3 inches of snowfall is expected across the WNW wind snow belts of both the western and eastern UP tonight, with higher embedded totals around 4-6in possible in the Porcupines, but the advisory will be extended only for Alger and Luce counties given the higher probability for travel impacts there. Otherwise, expect temperatures to turn much chillier tonight, with lows ranging in the teens to around 20F. In the interior-western UP, some spots may even see low temperatures flirting with the single digits. && .LONG TERM /THURSDAY THROUGH WEDNESDAY/... Issued at 343 PM EST Wed Jan 1 2025 The overall weather pattern will be dictated by the consequences of 500mb prolonged troughing over the eastern CONUS supported by persistent ridging over northeast Canada to southern Greenland. With cooler and cooler air flowing into the Upper Great Lakes, a northwesterly-flow LES regime remains, and while 500mb shortwaves pivoting around the primary trough over the Ontario/Quebec line will provide occasional synoptic boosts to the LES, the tracks of large- scale synoptic low pressure systems will be well to the south of the UP. A brief interruption to this pattern is possible early next week as ridging moves over the Upper Great Lakes Monday, but ensemble support for anomalous troughing over the Appalachians by the middle of next week is good, bringing some potential for even cooler air to move over the region. However, run-to-run and intra-ensemble consistency in the details of cool air is poor, so be wary of any sources that post maps of single deterministic model runs showing brutal cold air over the UP. For Thursday, NW LES bands will be ongoing. While deep saturated layers are present along with supportive lake-850mb deltaTs (around -15 C at 850mb to 5 C on the surface of the lake), inversion heights remain fairly shallow, with soundings showing only about 3-5kft inversion heights. With little change in the pattern, continued snowfall rates in the typical NW LES hotspots of around 1"/6hr continues except over Luce County, where some localized convergence could elevate snow totals, with the HREF showing up to 80% chances of snow rates exceeding 2"/6hr. Through Friday, 850mb temperatures will continue to fall, reaching near -20 C in some spots. Generally 1 to 4 inch per 12hr snowfall rates are expected, though some higher snow rates will be seen where localized convergence can be realized. As the prevailing 925mb wind direction is still highly confident to be within 30 degrees of 315 (>90% by Friday), long fetch into the eastern portions of the CWA will support higher amounts in eastern Alger and Luce counties, though advisory level snowfall is also expected in typical NW wind snow spots along the western UP shores of Lake Superior. The SLR might get a bit tricky as conventionally, cold advection to the extent of what`s expected to end this week typically plunges the entire convective layer into the DGZ, but soundings show that the best saturation layer might actually be above the DGZ, complicating the forecast somewhat. Also, continued shallow inversion heights and the potential for dry air intruding the lower portions of the DGZ per GFS soundings will cap the ceiling of snow totals below winter storm criteria. Approaching ridging will sharply cut into PoPs in the west over the weekend despite continued favorable thermodynamics. Uncertainty grows in the forecast next week as deterministic and ensembles struggle to agree on the magnitude and timing of ridging to the west moving over the Upper Great Lakes. From there, multiple pulses of shortwave troughs plunge southeast from the Canadian Prairie, ushering in cooler than normal temperatures, though the LREF only shows about 5-10% chances of temperatures of 0 or below for the KSAW area by the following weekend with only around 20% chances for the rest of the interior west for that period. In fact, the LREF shows better chances for sub-zero temperatures on Sunday the 5th for the Ironwood area at up to 30%. Looking beyond then, despite the calls for apocalyptic cold making the rounds on social media, the probability for -10 F or colder are only 10% at any time by the middle of the month per the Euro ensemble. With record low temperatures for this time of year around the -20 mark, it would take a dramatic shift in the models to reflect record cold potential. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 629 PM EST Wed Jan 1 2025 Little change in the weather pattern through the 00Z TAF cycle. West- northwest flow lake effect processes should continue, which will favor areas between IWD and CMX for the heavier lake effect snow, leaving the terminals on the fringes. Lift has been enhanced by a passing shortwave trough which may have helped CMX see slightly heavier LES with IFR vsby late afternoon/early evening, but expect MVFR cigs/vsby to prevail for the remainder of the TAF period (occnl dips to IFR remain possible, esp. through 03Z). For IWD, expect mainly flurries with VFR vsby and MVFR cigs, although occnl MVFR vsby cannot be ruled out. Late in the TAF period, winds shift more NWly which may bring more persistent snow showers toward 21Z. For SAW, expect MVFR cigs (and possible MVFR vsby in passing snow showers due to the passing trough at the start of the TAF period), becoming VFR in the wake of the wave. Should be borderline MVFR/VFR cigs much of the day on Thursday. && .MARINE... Issued at 343 PM EST Wed Jan 1 2025 Northwesterly winds will prevail through the first weekend of 2025, gradually building from around 25 kt through Thursday, up to 30 kt Thursday night, and then up to 90% chances of low-end gales by midday Friday. Internal model guidance suggests up to 30% chances of gales exceeding 40 kt by early Saturday. Winds fall to near 25 knots for Sunday before falling to 20-25 kt as winds go more northerly to kick off next week. Waves build to 4-7 feet by Thursday morning, gradually building to 6-12 feet by Saturday morning (highest near Grand Marais, MI). Waves then gradually fall to near 4 feet by Monday afternoon. Freezing spray is expected, especially with the gales, with heavy freezing spray possible in the north-central portions of the lake Friday night and Saturday morning. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory until 7 PM EST this evening for MIZ002- 003. Winter Weather Advisory until 7 PM EST Thursday for MIZ006-007. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...LC LONG TERM...GS AVIATION...Thompson MARINE...GS