Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/29/24


Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
459 PM MST Sat Dec 28 2024 ...New AVIATION... .KEY MESSAGES... Updated at 440 PM MST Sat Dec 28 2024 - Breezy west to northwest winds continue this weekend along and east of the central mountain chain. Otherwise tranquil weather will prevail around the region. - Strong west winds Monday will create hazardous crosswinds and patchy blowing dust that may reduce visibility at times. - Critical fire weather conditions in the eastern plains Monday afternoon will make for easier fire starts. && .SYNOPSIS... Issued at 325 PM MST Sat Dec 28 2024 Temperatures continue well above normal over the weekend, with temperatures nearing record highs for several locations along the eastern plains on Sunday and Monday. The main area of concern over the next several days will be strong winds over eastern New Mexico, leading to critical fire weather conditions on Monday. Winds diminish after Monday, and temperatures drop to near seasonal averages on Tuesday and Wednesday as a couple of backdoor fronts push through eastern New Mexico. Conditions look to remain dry and temperatures look to warm back up by the end of the week. && .SHORT TERM... (This evening through Monday night) Issued at 325 PM MST Sat Dec 28 2024 West-northwest flow will continue to dominate the wind regime for the next several days, with a shortwave trough passing through the intermountain west on Monday notching up wind speeds. Breezy conditions on Sunday will turn to stronger winds on Monday for the central mountain chain and central and northeast highlands, with gusts up to 50 mph. A 300mb jet of about 140kts will be over northern New Mexico, and a mid-level speed max of about 75 kts will be situated over northeast New Mexico. A surface low of about 995- 997 mb will deepen over central Oklahoma by the afternoon hours. This set up will lead to widespread gusty winds for the eastern half of the state and into the Great Plains through monday evening. The timing of the upper and mid level jets over New Mexico look to be during the morning hours on Monday. The northern mountains and northeast plains could see 30+ mph gusts before sunrise, with stronger winds then shifting to the central plains by mid-day as the trough moves through and daytime heating allowing for stronger winds to mix down. Take caution while driving on Monday, as there will be hazardous crosswinds for motorists driving along N-S oriented roadways, as well as a potential for patchy blowing dust reducing visibilities along the central and eastern plains. Another concern, in association with these strong winds, will be critical fire weather conditions for the eastern plains of New Mexico. Warm and dry conditions with temperatures in the upper 60s and dewpoints in the low teens, in conjunction with gusts 35+ mph on Monday, greatly increase the risk of fire. As a result, a fire weather watch has been issued for the eastern plains for Monday afternoon. Other than winds, weather will be warm and dry for the short term. 500mb heights between 574 and 580 dm over New Mexico will help bump temperatures 15 to 20 degrees above average for this time of year throughout the state. Downsloping winds will further increase high temperatures for the eastern plains with several locations nearing record high temperatures on Sunday. Temperatures cool throughout the western half of the state on Monday as the shortwave trough pushes through, but continued downsloping winds will once again create near record highs for the southeast plains. && .LONG TERM... (Tuesday through Friday) Issued at 325 PM MST Sat Dec 28 2024 As westerly winds die down, a backdoor cold front will sweep through eastern New Mexico on Tuesday morning. Meanwhile, another shortwave will dig in through the Four Corners on Tuesday afternoon, with 500mb heights dropping to around 560dm for most of the state. This will result in a brief cool down, with high temperatures 15 to 20 degrees below those observed on Monday for the eastern NM. Guidance does hint at some light snowfall for the northern mountains, but the trough passage looks to be fairly dry, so any precipitation looks to be isolated to the mountains along the CO-NM border. As this shortwaves moves on east, it will push another backdoor through the eastern plains on Wednesday morning, keeping high temperatures below normal once again. Towards the end of the week, another shortwave looks to clip the northern part of the state and bring some breezy conditions for the central mountains and central highlands, as well as another backdoor on Friday. Currently, most ensemble guidance is in agreement of ridging building back up for the Friday through Saturday period, keeping conditions warmer and drier, but some guidance is hinting at a developing system towards the end of the weekend which could bring precipitation back into the forecast. && .AVIATION... (00Z TAFS) Issued at 440 PM MST Sat Dec 28 2024 High (90%) confidence in VFR prevailing at all terminals over the next 24 hours. Brisk NW flow at ridge-top levels (e. g., ~50KT at 700mb, per latest RAP analysis) causing some reported mountain wave activity in the lee of the Sangre de Cristo range, with a Center Weather Advisory from ZAB currently in effect. Mid-level flow gradually veers more WNW over the next 24 hours but remains at similar magnitude. This could lead to some LLWS near KLVS overnight, but confidence only low-to-moderate (30%) at this time, as uncertainty remains about extent of surface wind decoupling. Both RAP forecast soundings and blended LLWS guidance suggest higher confidence for LLWS at KROW, so have included it for late tonight into Sunday morning. Gusty winds develop at KGUP after 21Z Sunday in advance of a disturbance in the broader NW flow. && .FIRE WEATHER... Issued at 325 PM MST Sat Dec 28 2024 An active fire weather pattern takes hold Sunday through Monday, peaking in strength Monday afternoon when critical fire weather conditions are expected to develop across a large swath of the eastern plains of NM. Well above normal warmth reaching record levels for some spots will be present Sunday afternoon alongside breezy to locally windy westerly to northwesterly winds. Elevated fire weather conditions will be present. Winds strengthen considerably late Sunday night thru Monday as an upper level storm system clips northeastern NM and southeastern CO. Strong WNW to NW winds will mix down to the surface along and lee of the central mountain chain thru the day. These winds subside by the evening, ending critical fire weather concerns. A backdoor cold front will swing southward from CO Tuesday dropping highs back below normal alongside a northeasterly to easterly wind shift. Relatively warmer weather will remain thru central and western NM alongside persisting fair to good ventilation. Another quick-hitting storm system clips northeastern NM late Tuesday bringing a Pacific cold front across the state. Little if any winter precipitation will reach the northern mountains from this system. High pressure ridging takes hold after Wednesday allowing for a warming trend, lighter winds, and poor ventilation. && .PRELIMINARY POINT TEMPS/POPS... Farmington...................... 25 54 27 49 / 0 0 0 0 Dulce........................... 13 53 16 49 / 0 0 0 0 Cuba............................ 26 56 26 48 / 0 0 0 0 Gallup.......................... 19 61 21 54 / 0 0 0 0 El Morro........................ 23 58 28 52 / 0 0 0 0 Grants.......................... 20 62 25 55 / 0 0 0 0 Quemado......................... 25 63 28 55 / 0 0 0 0 Magdalena....................... 33 65 36 59 / 0 0 0 0 Datil........................... 27 63 34 56 / 0 0 0 0 Reserve......................... 23 63 21 66 / 0 0 0 0 Glenwood........................ 30 65 36 68 / 0 0 0 0 Chama........................... 20 46 18 43 / 0 0 0 0 Los Alamos...................... 29 57 34 48 / 0 0 0 0 Pecos........................... 31 56 31 50 / 0 0 0 0 Cerro/Questa.................... 24 50 27 45 / 0 0 0 0 Red River....................... 20 43 23 34 / 0 0 0 0 Angel Fire...................... 16 49 21 41 / 0 0 0 0 Taos............................ 20 53 23 48 / 0 0 0 0 Mora............................ 29 58 29 46 / 0 0 0 0 Espanola........................ 25 59 26 56 / 0 0 0 0 Santa Fe........................ 31 55 31 51 / 0 0 0 0 Santa Fe Airport................ 27 57 27 53 / 0 0 0 0 Albuquerque Foothills........... 34 59 38 56 / 0 0 0 0 Albuquerque Heights............. 31 60 33 58 / 0 0 0 0 Albuquerque Valley.............. 29 62 31 61 / 0 0 0 0 Albuquerque West Mesa........... 30 60 33 58 / 0 0 0 0 Belen........................... 27 63 28 63 / 0 0 0 0 Bernalillo...................... 30 61 33 58 / 0 0 0 0 Bosque Farms.................... 28 62 27 60 / 0 0 0 0 Corrales........................ 30 60 32 58 / 0 0 0 0 Los Lunas....................... 28 63 29 61 / 0 0 0 0 Placitas........................ 32 60 36 53 / 0 0 0 0 Rio Rancho...................... 29 59 33 58 / 0 0 0 0 Socorro......................... 31 67 33 68 / 0 0 0 0 Sandia Park/Cedar Crest......... 31 56 33 49 / 0 0 0 0 Tijeras......................... 32 58 35 51 / 0 0 0 0 Edgewood........................ 28 58 32 52 / 0 0 0 0 Moriarty/Estancia............... 24 61 28 55 / 0 0 0 0 Clines Corners.................. 30 56 31 51 / 0 0 0 0 Mountainair..................... 29 60 34 55 / 0 0 0 0 Gran Quivira.................... 29 61 31 58 / 0 0 0 0 Carrizozo....................... 37 63 35 61 / 0 0 0 0 Ruidoso......................... 38 61 41 57 / 0 0 0 0 Capulin......................... 30 60 33 52 / 0 0 0 0 Raton........................... 29 62 33 55 / 0 0 0 0 Springer........................ 25 66 33 58 / 0 0 0 0 Las Vegas....................... 31 63 35 55 / 0 0 0 0 Clayton......................... 35 65 41 62 / 0 0 0 0 Roy............................. 30 67 38 59 / 0 0 0 0 Conchas......................... 31 70 42 67 / 0 0 0 0 Santa Rosa...................... 38 68 42 63 / 0 0 0 0 Tucumcari....................... 32 70 42 68 / 0 0 0 0 Clovis.......................... 36 71 43 67 / 0 0 0 0 Portales........................ 36 71 43 68 / 0 0 0 0 Fort Sumner..................... 38 73 42 67 / 0 0 0 0 Roswell......................... 37 75 41 76 / 0 0 0 0 Picacho......................... 44 73 46 68 / 0 0 0 0 Elk............................. 43 71 45 66 / 0 0 0 0 && .ABQ WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Monday morning through Monday afternoon for NMZ104-126. && $$ SHORT TERM...25 LONG TERM....25 AVIATION...53-Schroeder
Area Forecast Discussion
National Weather Service Denver/Boulder CO
836 PM MST Sat Dec 28 2024 .KEY MESSAGES... - Heavier mountain snows continue today with an additional wave Sunday evening into Monday. - Strong winds expected to continue today and tonight, tapering off a tad on Sunday. Gusts upwards of 60 MPH likely (80-90%) in the high country during this time frame. Even stronger and more widespread winds and gusts on Monday exceeding 60 MPH. - Windy Monday with at least elevated if not critical fire weather concerns. Relatively high probabilities (>50% chance) of reaching high wind criteria over portions of the foothills and plains. - A weak disturbance or two in northwest flow Tuesday into Wednesday could bring a couple light snow showers, favoring the mountains. - Colder temperatures are expected for New Year`s Eve and start to 2025 (Wednesday). Then gradual warming again the end of next week. && .UPDATE... Issued at 822 PM MST Sat Dec 28 2024 Conditions are progressing as expected in the high country with snowfall gradually filling in across higher elevations. Water vapor imagery shows deeper moisture upstream that will enter our forecast area overnight and sustain light to moderate snow in the mountains. Did introduce a few rain showers into the forecast for our north/northeast plains for the next few hours, in association with the upper level shortwave across the northern US plains. Additionally, opted for a rather unorthodox evening update to our high wind headlines given the latest trends in hi-res guidance for Monday. Will leave the finer details up to the night shift to discuss, but multiple factors (including very strong QG descent, jet dynamics, weak 700-500mb wind shear, and indications of an inversion aloft) suggest increased potential for damaging winds meeting high wind criteria for our central/northern foothills and adjacent lower elevations. This is reflected in some eye-catching wind gusts in a few of the most recent model runs, with the HRRR leading the pack. These areas are therefore now included in the High Wind Watch for Monday to capture this possibility. && .SHORT TERM /Through Sunday/... Issued at 222 PM MST Sat Dec 28 2024 Today...The orientation of the upper level jet isn`t great for orographics across a majority of our mountains and the stream is a fairly warm stream so snow ratios are pretty wet. That being said, there is quite a bit of moisture upstream that needs to move through the region so we still hold onto the warning across the northern mountains and advisory south and east...still have another 12-hours to go and enhanced returns are starting to fill back in on the regional radar scope upstream. Expect an additional 12-20 inches in the northern mountains with 6-10 across the central mountains. Gusty winds, pushing 60 MPH, still a good bet through much of the evening and overnight hours, mainly above 10kft with 30-40 MPH gusts between 7kft and 10kft. Sunday...As this current wave and pacific jet stream through we should start to see weak ridging and weak subsidence take over putting an end to much of the mountain snowfall...for a few hours at least. The footprint of the stronger winds is shunted back to the west, mainly above 10 kft, leaving much of the region on the calmer side. We keep temperatures elevated on Sunday though as mentioned before standing mountain waves may knock off a few degrees across the urban corridor and adjacent foothills. Either way we`re above seasonal temperatures again. The next wave, tied to an even stronger pacific jet, begins to impact the region later Sunday evening through much of the day Monday. A 140-150 knot upper level jet streak puts much of our region in the left exit region and the nearly zonal flow will really help to crank out moisture. Combine the moisture, strong westerly upslope and a bora type front wind event, Monday will see impacts from not only heavy mountain snows, but also fire weather and high winds. && .LONG TERM /Sunday night through Saturday/... Issued at 222 PM MST Sat Dec 28 2024 As mentioned above, there is a lot going on to start the long term forecast period. The highlights for Monday involve winter, wind, and fire weather headlines. Beginning with the winter portion... Multiple rounds of snow will continue to impact the northern Colorado mountains. With an upper-level trough bringing another stream of Pacific moisture into the high country, and the aforementioned jet streak providing ample lift Sunday night and through the day Monday, we have issued an additional Winter Storm Warning for the Park and Gore Ranges from 8PM Sunday through 5PM Monday, with additional snow accumulations between 8 and 12 inches possible. Additionally, a Winter Weather Advisory has been issued for the same time for the rest of the northern/central mountains where another 3 to 7 inches of snow will be possible Monday. Strong winds are expected with this system with gusts to 70 mph possible that will lead to reduced visibilities due to blowing snow. Unfortunately, the moisture seems to be anchored to the mountains, but there is a chance some of it makes its way down into the foothills and northern plains, however, any that does will be light. Winds... With a stable layer near ridgetop, 40+ kt cross-barrier flow, and cold air advection, a bora wind event is expected. We have issued a High Wind Watch for northwest winds of 30-40 kts with gusts up to 60 mph for our eastern plains. Winds are expected to pick up along the northern border early Monday morning before shifting south by late morning. At this time, we have left out wind headlines for our mountains and foothills, however, the latest run of the HRRR has a significant uptick in wind gusts along the eastern slopes of the Front Range Mountains (gusts to 100mph), we will hold off on issuing as this seems to be an outlier, but will monitor trends as new guidance comes out and assess as needed. It should be noted, that with dry soils across our eastern plains, these strong winds could lead to patches of blowing dust that could lead to reduced visibilities at times. Fire... With these strong winds comes heightened fire weather concerns. While relative humidities are forecast to remain above 30% for the majority of the forecast area, these strong winds and compressional warming off the Cheyenne Ridge and Front Range Mountains will lower relative humidities to near critical levels for areas along the southern foothills, Urban Corridor, metro Denver, and southern plains. For this reason, we have issued a Fire Weather Watch for these locations from Monday morning through the afternoon. On top of the strong winds, fuels are currently at critical status across our lower elevations (roughly 7,500` and below), if a fire were to start, rapid fire spread would be likely. Stay tuned for updated highlights in the coming forecast packages. After Monday, things begin to calm down. There will be another quick few shots of mountain snow showers as a few weak disturbances pass through Tuesday and Wednesday into Thursday. We are still on track for a cooler than average New Year`s Day and for upper-level ridging to build back in across the western US that will bring a return of warmer and drier conditions. && .AVIATION /00Z TAFS through 00Z Monday/... Issued at 422 PM MST Sat Dec 28 2024 All terminals east of the mtns will be VFR through the TAF period. Wind speeds will be relatively light through the next 24-36 hours, particularly for KAPA/KDEN, and with that comes greater uncertainty as far as wind directions. There`s potential for a brief window of winds from the ENE all the way to SSE later this evening at KDEN, but guidance is very mixed and with speeds expected to remain below 10 kts, will extend the current VRB a few more hours. Southerly drainage flow should prevail overnight and into Sun AM. Direction uncertainty increases again for Sun PM, especially 19-23Z will mixed signals for positioning of a weak Denver cyclone, but generally favors some form of a southerly component much of the day. && .FIRE WEATHER... Issued at 222 PM MST Sat Dec 28 2024 Critical fire weather conditions may develop Monday due to strong, gusty winds. Humidity levels will stay above traditional critical thresholds, but the magnitude of winds (gusts 45-60 mph likely across all of the foothills and plains) and recent dryness/lack of snow cover means high grassland fire danger. Have issued a Fire Weather Watch from Monday morning through Monday evening for the southern foothills, Urban Corridor, metro Denver, and southern plains. Stay posted for potential highlight changes. && .BOU WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 11 AM MST Sunday for COZ031. Winter Storm Warning from 8 PM Sunday to 5 PM MST Monday for COZ031. Winter Weather Advisory until 11 AM MST Sunday for COZ033-034. Winter Weather Advisory from 8 PM Sunday to 5 PM MST Monday for COZ033-034. Fire Weather Watch from Monday morning through Monday afternoon for COZ216-238>240-245>247. High Wind Watch from late Sunday night through Monday afternoon for COZ035-038-039. High Wind Watch from late Sunday night through Monday afternoon for COZ042>044-048. High Wind Watch from Monday morning through Monday afternoon for COZ045>047-049>051. && $$ UPDATE...Rodriguez SHORT TERM...Heavener LONG TERM...Bonner AVIATION...Rodriguez FIRE WEATHER...Bonner
Area Forecast Discussion
National Weather Service Columbia SC
716 PM EST Sat Dec 28 2024 .SYNOPSIS... The wedge front begins to move west and break this evening and tonight, bringing warmer and wetter conditions into Sunday. Sunday will be warmer and breezy with showers and thunderstorms likely along and ahead of an approaching cold front, with some severe thunderstorms possible. High pressure builds in behind the front for Monday, before the next chance of rain arrives on Tuesday. Cooler and drier conditions follow for the mid to late week period. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Key Message(s): - Increasing low level moisture and the residual wedge front will continue the drizzly dreary conditions this evening and overnight. - Some dense fog is possible through early Sunday. The sharp shortwave that will bring Sunday`s severe risk is still well to our west across the ARK-LA-TEX as of 8pm. Ahead of this system, increasing low level moisture and the residual wedge boundary in the Midlands will keep the drizzle and light rain overnight. The wedge boundary has shifted northwestward, with Columbia now in the 60`s with a very moist dew points also in the 60`s; the boundary looks to be across McCormick, Newberry and then up through Chester, York coutnies. South and east of the boundary, dew points are very high (above any guidance), sitting in the mid 60`s in Orangeburg, Barnwell, and Bamberg. The short term impact of this is dense fog potential overnight, but this may also play a role in Sunday`s severe potential as this low level moisture surges northwest into early Sunday. Recalibrating the HREF trends with current obs, the wedge boundary should lift into the Upstate and allow 60+ F dew points to overspread basically the entire forecast area by 7am as the rapidly strengthening 850mb pushes in early Sunday morning. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/... Key Message(s): - A line of shower-storms will push through in the morning and early afternoon. Some thunderstorms could become strong to severe, with damaging winds as the primary threat. A few brief tornadoes are also possible. - Warmer and breezy the rest of Sunday with a Lake Wind Advisory in effect from 7am until 3pm. Sunday and Sunday Night: The ingredients for an active weather day are present across the forecast area. The latest Day 2 SPC SWO maintains a Slight (2/5) risk for severe weather across the entire CWA, with much of the area in a 5% Tornado risk. These probabilities are driven by the approach of a potent negatively tilted trough and the associated surface cyclone and attendant cold front, which will move through the FA during the afternoon and early evening hours. Some members of the guidance suite continue to suggest there will be two rounds of convection, the first will be the remnant showers and thunderstorms currently moving through eastern Texas and Louisiana with a second round, potentially stronger round, accompanying the cold front. Confidence is high that the first round of convection will be moving into our western counties during the early to mid morning hours. The main deterrent for severe weather with this line will be the lack of instability, which is unsurprising considering the time of day and the retreating wedge. The second line arrives in the afternoon, but there is uncertainty regarding how much instability can develop in the break between the first line and the second. The 12Z HRRR is the most bullish on the scenario of a strong secondary line of convection, while other HREF members don`t materialize it at all or show it much weaker. Considering the convective mode should mostly be linear in nature, damaging winds will be the primary severe hazard with any thunderstorms that develop. If the HRRR solution is correct, a few brief tornadoes cannot be ruled out, especially should any discrete cells develop. Looking at the HREF, it appears the greatest threat for severe weather with the second line, should it materialize, will be south and east of I-20 where the probability of CAPE in excess of 500 J/kg and 0-6km shear in excess of 30 knots is highest. In summary, while confidence in scattered to widespread showers and thunderstorms is high, 70 to 90 percent, confidence in severe weather is lower and will be highly conditional. Outside of the convective potential, Sunday should be 5-10 degrees warmer than today, with above normal daytime temperatures expected as the wedge should fully retreat from the region. It will be breezy as well, especially on area lakes, prompting the issuance of a Lake Wind Advisory from 7am until 3pm tomorrow. Rain chances should end quickly in the evening as the cold front clears the forecast area, followed by partial clearing at night. Monday and Monday Night: A warm and dry day is expected as the air mass behind the cold front is not much cooler. Daytime temperatures remain above normal and are similar to Sunday in most locations. Mainly clear skies and light winds at the start of the night will likely result in slightly cooler overnight lows, however it looks like clouds associated with the next storm system will arrive prior to daybreak Tuesday, limiting radiational cooling and resulting in above normal low temperatures. Tuesday and Tuesday Night: Another shortwave and storm system will pass to our north. This will result in a chance of rain, mainly across the Northern Midlands where the best lift will be located. The Southern Midlands and CSRA may remain dry on Tuesday, resulting in warmer daytime temperatures there. A cooler air mass moves in behind this system, but temperatures Tuesday Night should still be above seasonal values for the end of December. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... Key Message(s): - Cooling trend follows for the mid to late week period. Confidence is high regarding the pattern during the opening days of 2025. High pressure emerges from the Intermountain West on Wednesday, moving overhead on Friday. This will result in a period of dry weather with seasonal temperatures Wednesday through Friday. The next chance of precipitation should hold off until late next weekend. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... High confidence in LIFR/IFR restrictions again dominating the period with improvement very late. Wedge continues to cause highly variable conditions across the area with MVFR to VFR at CAE/CUB/OGB and LIFR at AGS/DNL. Over the next several hours expect the wedge boundary to slide a bit more westward and allow conditions at AGS/DNL to improve high end IFR with scattered showers persisting at all terminals. Toward daybreak winds will become southeasterly while low level winds quickly increase resulting in LLWS from 07z through the end of the period. Main focus for the period will be potential for convection moving into the area during the morning hours. Have remained with TSRA at all terminals and will continue to monitor strong to severe thunderstorm potential along with convective gusts to 40s mph and adjust as confidence improves. EXTENDED AVIATION OUTLOOK...Ceiling and visibility restrictions rapidly improving to VFR Sunday evening. Restrictions possible Tuesday mainly at CAE/CUB as the next system rapidly moves through the region. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...Lake Wind Advisory from 7 AM to 3 PM EST Sunday for SCZ016-018- 020>022-025>031-035-037-038-041-115-116-135>137. GA...Lake Wind Advisory from 7 AM to 3 PM EST Sunday for GAZ040- 063>065-077. && $$
Area Forecast Discussion
National Weather Service State College PA
1016 PM EST Sat Dec 28 2024 .SYNOPSIS... * Foggy, then mild and wet Sunday. * Still mild but mainly dry on Monday. * More wet weather Tuesday. * Colder weather will return for the second half of the week. && .NEAR TERM /UNTIL 9 AM SUNDAY MORNING/... Fog is expanding steadily into the rest of the CWA. The highest elevations of the Laurels are still without, but the wind is getting lighter, and T getting closer to Td. Have expanded the DFA to all but Warren, Cambria and Somerset Cos. They may need to be added eventually, as well. New/00Z NAM continues to bring a band of showers across from S to N later tonight as lift north of the very strong LLJet makes the precip happen. HRRR and RAP agree. Feel confident leaving the high PoPs in for the overnight. Prev... Lots of low clouds cover the eastern 2/3rds of the CWA, and they are lowering a bit. There are already patches of dense fog around, mainly where the clouds hit the hill tops, but MDT, LNS, SEG are also having the visby go down. The light wind and plentiful moisture trapped under the inversion will make it easy for fog to expand and get thicker. Have issued a dense fog advisory for much of the area, and expect to have to expand it through the evening, or later tonight. Deep mixing is not really expected until later in the morning. Western locations are likely wondering what all the fuss is about regarding fog. But, their mainly clear (high clouds only right now) condition will get cloudier and they, too, should have fog by morning. The clear sky and higher dewpoints over that way make it an almost certainty. But, they do have some wind at this time. The first part of the night will feature a gradual expansion northward of drizzle as the clouds thicken up (along with the fog). Later, forcing aloft should increase and perhaps make some steadier rain/larger drops. That may actually improve the visibilities, but the better bet for now is fog to continue. Temps are abnormally high for the west right now, and they might end up staying milder than record maxi-mins. JST needs to stay aoa 45F (2019) and BFD 43F (1984). && .SHORT TERM /9 AM SUNDAY MORNING THROUGH TUESDAY/... Trend has been for a bit less QPF now for Sunday. Also SPC did trim outlook out of our far western areas. Main change I made was to up temperatures a bit Sunday into Monday, given the gusty southwest flow expected to develop on Sunday. Some of the showers will likely be on the heavy side later Sunday, but the system still looks like it will move along through our area. While the low tracks to the west, before reforming to the east, dynamics and low low moisture would support a small chance for rumble of thunder. Most of Monday and the first part of Tuesday look dry, with temperatures warmer than normal. Earlier information below. As the surge of milder air begins to work on low-level lapse rates, southerly wind gusts of 30-40 mph may develop on some of the ridge tops and also areas where southerly winds downslope. Locally heavy downpours are also anticipated Sunday afternoon and evening, as precipitable water values surge upwards of 1.3" for southern sections of the Commonwealth, with these values in the 90th+ percentile for late December. Despite locally heavy rainfall, long-term dryness for many areas, plus lack of convection and enhanced rates, are expected to keep this situation manageable from a hydro perspective. By later Sunday night and Monday, as an initial cold front sweeps across the region, steadier rain will come to an end. Temperatures will be cooler, but not yet cold (that waits for later in the week). && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Upper level ridging attempts to build in behind a departing shortwave Monday night which will allow for a brief dry period, but rain chances quickly increase again late Tue as weakening surface low tracks through the region. The latest ensemble runs have trended downward in terms of QPF amounts; however, widespread rain still appears likely for much of Tuesday night. Much colder air will begin working its way in from the west as this system exits the region and may allow for some snow to mix in across the northern and western mountains Wednesday morning. Temperatures trend lower towards the end of the week with most locations seeing highs around 5 degrees below normal by Thursday. A tight pressure gradient behind the departing low will make for a breezy day on Thursday with gusts of 30 to 40 mph across the Alleghenies. West-northwest flow will also support lake effect and upslope snow showers through the end of the week. A quick look at temperature trends beyond Friday indicates the cold temperatures are likely to stick around this weekend and into next week as a strong ridge is progged to build over the western US, leaving the Ohio Valley and Mid- Atlantic region with a deep digging trough over the region next week. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... Widespread fog has developed across Central PA and will continue to lead to IFR/LIFR restrictions through the night for sites east of BFD and JST. Model soundings suggest that the low level moisture will eventually make it to those two sites as well, but there is some uncertainty as to the exact timing of when restrictions develop and how low CIGs/VSBY get before 06Z. After 06Z, light rain will begin moving into the region ahead of a deep low pressure system that will track to the west of the region on Sunday. There is high confidence in IFR/LIFR conditions area-wide once the rain moves in. A strong 50+ kt southerly 850mb jet will build across the region on Sunday and create low-level wind shear concerns. Even with 20 to 30kt surface wind gusts expected, speed shear will be a concern. Models still indicate that very weak elevated instability will work its way into southwestern parts of Central PA (JST and AOO) during the late afternoon which could allow for a few lightning strikes, but confidence is low. Outlook... Mon...Rain chances decrease west-to-east late with lingering rain possible; gusty west winds gradually taper off. Tue...Increasing clouds with rain expected again late. Wed...Rain continuing with snow mixing in west of UNV; gusty west winds. Thu...Restrictions at JST and BFD in -SHSN; gusty west winds. && .CTP WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 9 AM EST Sunday for PAZ005-006- 010>012-017>019-025>028-034>037-041-042-045-046-049>053- 056>059-063>066. && $$ SYNOPSIS...Dangelo/Martin NEAR TERM...Dangelo SHORT TERM...Dangelo/Martin LONG TERM...Bauco/Bowen AVIATION...Banghoff/Bauco
Area Forecast Discussion
National Weather Service Grand Forks ND
952 PM CST Sat Dec 28 2024 .KEY MESSAGES... - Chance for patchy dense fog overnight into Sunday morning for the Red River Valley and northwestern and west central Minnesota. - Confidence is increasing on very cold wind chills mid next week for portions of eastern North Dakota. && .UPDATE... Issued at 952 PM CST Sat Dec 28 2024 Patchy fog has developed along the international border in ND this evening. A dense fog advisory has been issued for some Lakes country counties in MN as there is better confidence in dense fog developing there into tomorrow morning. Otherwise, forecast remains on track. UPDATE Issued at 651 PM CST Sat Dec 28 2024 Clouds are creeping in from the west, and fog is encroaching in the east this evening. More dense fog is possible, especially in the MN counties of our area, but widespread patchy fog is also possible across the area. Forecast remains on track. && .DISCUSSION... Issued at 222 PM CST Sat Dec 28 2024 ...Synopsis... Zonal flow continues through the remainder of today and tomorrow followed by northwesterly flow as a Hudson Bay low develops early next week. Under the zonal flow we will continue to have some low level saturation and light and variable winds. This brings another round of patchy dense fog to portions of the region. Flow transitions to northwesterly end of the weekend and early next week bringing a quick clipper system to western North Dakota and South Dakota. A brief rain/snow mix or light snow shower may be possible late Monday for portions of Sargent county. Cold air advection moves down from Canada out of the NW flow bringing very cold wind chills by mid week to portions of eastern North Dakota. Ensembles have hinted at another clipper type system moving out of the northwesterly flow end of the work week and into the following weekend. However, predictability is low and so is confidence in any development, track, and strength of said system. ...Patchy Dense Fog... Current satellite has a broad area of clearing in eastern North Dakota and northwestern/west central Minnesota bringing plentiful sunshine and warmer temperatures. Had to increase highs for the day into the upper 30s, with pockets of low to mid 40s where snowpack is shallower. Low level saturation lingers through the area today and into the evening hours helping to produce further fog chances for the area. Winds will be light and variable overnight and into the morning hours Sunday for areas east of the Sheyenne River Valley and Devils Lake Basin. Confidence is low on how widespread fog may get, but HREF and HRRR guidance continues to show the chance for patchy dense fog for the Red River Valley points eastward overnight. This will all be dependent on the depth of low level saturation, winds, and how long the clearing lasts. Satellite does show high level clouds shifting east northeast into the forecast area which may help reduce fog chances. None the less, there is a chance for patchy dense fog overnight which may reduce visibilities down to quarter of a miles or less. ...Colder Temperatures... Temperatures drop quickly in areas of clearing overnight, with portions of the Devils Lake Basin hitting the low to mid teens. Untreated surfaces may refreeze quickly overnight and create slick conditions at times for Sunday morning. Colder temperatures are on the horizon as cold air advection pools down from Canada Monday onward. A quick clipper system moves through Tuesday evening through Wednesday morning bringing light snow shower chances to portions of north central Minnesota. It also brings stronger cold air advection helping to drop morning lows Thursday and Friday into the negative single digits and negative teens. Coldest temperatures will be where snowpack is deeper (Devils Lake Basin through International Border). High temperatures end of the week range from the single digits in the north and the lower teens for areas where snow cover is shallower (southern Red River Valley). Chances increase for very cold wind chills in the Devils Lake Basin mid to late next week. We will continue to monitor the cold temperatures arriving for the new year. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 530 PM CST Sat Dec 28 2024 Main concerns into the Sunday TAF period are the ceilings lowering right around sunrise as fog settles back in tonight. Expect reduced visibilities as low as 1/2sm and ceilings could possibly get in the LIFR category briefly. Winds will be light and variable through the TAF period. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...Dense Fog Advisory until noon CST Sunday for MNZ016-017-023- 024-028-031-032. && $$ UPDATE...AH DISCUSSION...Spender AVIATION...AH
Area Forecast Discussion
National Weather Service Green Bay WI
948 PM CST Sat Dec 28 2024 New Information added to update section .UPDATE... Issued at 947 PM CST Sat Dec 28 2024 Fog is rapidly developing across central Wisconsin this evening. HREF and mesoscale models continue to show a strong signal for dense fog to spread across most of the rest of the area through the evening hours. The signal for dense fog is not as strong across the far northeast (Oconto, Marinette, and Door counties). Therefore, will issue a Dense Fog Advisory for most of the area as we are starting to see the fog developing per the previous model runs. If the fog makes it to the far northeast later tonight will add the remaining counties to the advisory as needed. Once the fog develops the models gradually dissipate the fog Sunday morning, with much of the fog dissipated around noon. Although the fog could linger across the Fox Valley into the early afternoon, will keep noon as an expiration time and let subsequent shifts adjust the timing as necessary. The fog itself could become freezing fog as temperatures drop below freezing, which could cause slick roadways overnight. && .KEY MESSAGES... - Areas of dense freezing fog are possible late tonight into Sunday morning, especially in central and north-central Wisconsin. In addition to visibility reduced to less than one- half mile, untreated roads, bridges and overpasses could become slippery. Disruptions to air travel are possible. - Much colder air will return to Wisconsin late next week with sub zero wind chills expected Thursday, Friday and Saturday nights. && .DISCUSSION... Issued at 257 PM CST Sat Dec 28 2024 Short Term...Tonight and Sunday Latest RAP analysis shows a low pressure system lifting north over Lake Superior this afternoon. Any light lingering precipitation across northern WI should come to an end late this afternoon as the low continues to lift away from the area. The departure of the low should also allow clouds to scatter out across much of the region retuning sunshine to the area for the fist time in several days. The main focus for the remainder of the short-term is possible fog/freezing fog develop tonight into Sunday morning. With westerly winds diminishing this evening and ample low-level moisture from last night/today`s rain. Clearing skies should allow temperatures to easily fall past cross over temperatures. HREF probs also support fog development with a swath of 70-80% chances for visibilities less than 1/2 mile from around midnight through Sunday morning. Freezing fog looks most likely across northern and central WI where temps are forecast to fall into the middle 20s. This may result in a few slippery spots on untreated roads, bridges, or sidewalks Sunday morning. There is more uncertainty with when fog lift and become low- clouds Sunday as forecast soundings show a rather sharp inversion just off the surface. The RAP is more conservative end of the spectrum with fog lingering into Sunday afternoon across central and east-central WI, while the HRRR shows the fog clearing from much of the region by noon. Once the fog does clear Sunday a weak-mid level ridge developing over the region should bring quiet weather for the remainder of the day. There is a low-end chance (10-15%) for a period of light along the lakeshore Sunday afternoon as a low lifts northeast through the Ohio Valley, but expect much of the precip with this system to miss the forecast area. Long Term...Sunday Night Through Saturday Much colder weather will return to Wisconsin by the end of next week as the upper jet pattern shifts from nearly zonal flow to the northwest. The transition should begin on New Year`s Day, as temperatures return to normal, and become gradually colder after that. The models are in agreement that there will be some kind of winter storm moving from Southern Colorado to Lake Michigan around the 5th, that should bring snow to our area, and then a blast of arctic air after it departs. The ECMWF has an almost classic Colorado low moving towards Chicago, while the GFS has more of a split upper flow and less intense surface low. Sub zero wind chills are expected next Thursday, Friday and Saturday nights. Even colder wind chills are possible the following week if the current models are correct. && .AVIATION...for 00Z TAF Issuance Issued at 523 PM CST Sat Dec 28 2024 CIGs varied between VFR across much of central and east-central Wisconsin with IFR stratus across north-central Wisconsin. Conditions tonight will be favorable for fog/freezing fog to develop at all TAF sites beginning around 04Z/10PM as westerly winds diminish and become calm overnight. Temperatures tonight are expected to fall below freezing away from Lake Michigan, so have freezing fog in all the TAFs except for MTW, where surface temperatures should remain the middle 30s. There is uncertainty with when fog might lift Sunday, but do expect IFR/MVFR vsbys to linger through much of the morning, and into the early afternoon hours, especially at the eastern TAF sites. && .GRB WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until noon CST Sunday for WIZ005-010>012- 018>020-030-031-035>040-045-048>050. && $$ UPDATE.........Kurimski DISCUSSION.....GK/RDM AVIATION.......Kurimski
Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
524 PM CST Sat Dec 28 2024 .KEY MESSAGES... - Rain will overspread much of central Illinois east of the Illinois River tonight into Sunday. Storm total rainfall will be greatest along/east of I-57 where the 12z HREF shows a 70-100% for greater than 1 inch. - Much above normal temperatures will continue through Monday before a strong cold front passes and causes readings to drop below normal into the 20s by the end of next week. && .SHORT TERM...(Tonight through Sunday) Issued at 211 PM CST Sat Dec 28 2024 A vigorous short-wave trough evident on 19z/1pm water vapor imagery over northern Texas will pivot northeastward over the next 24 hours...reaching northern Indiana/Ohio by Sunday evening. Thanks to copious Gulf of Mexico moisture flowing northward and an unstable airmass, a significant severe weather event is currently unfolding across the lower Mississippi River Valley. While the severe activity will remain well south of central Illinois tonight, widespread showers will overspread much of the KILX CWA later this evening through at least midday Sunday. 12z models are in relatively good agreement concerning the time of arrival and areal coverage of the precip...with consensus suggesting the most widespread/consistent showers occurring along/east of the I-55 corridor. Areas further west across the Illinois River Valley will likely remain mostly dry. Rainfall amounts will vary greatly from west to east across central Illinois. While some locations along/west of the Illinois River will see zero rainfall, 12z HREF shows a 70-100% chance for greater than 1 inch along/east of I-57. A low probability (10-20% chance) for greater than 2 inches exists along/southeast of a Robinson to Olney line. The 18z HRRR even shows amounts approaching 3 inches, but think this may be a bit overdone given the scope of the severe event happening upstream which may tend to limit northward moisture transport somewhat. The official forecast features totals of 1-1.50 along/east of I-57...with amounts approaching 2 inches along/southeast of a Robinson to Olney line. Rain will be ongoing Sunday morning, then will gradually diminish from west to east during the afternoon. While the steadiest showers will shift into the Great Lakes/Indiana as the day progresses, cannot rule out a few stray light showers or drizzle through the afternoon and even into Sunday evening as the short- wave lifts into Michigan. Barnes .LONG TERM...(Monday through Next Saturday) Issued at 211 PM CST Sat Dec 28 2024 Short-wave ridging will develop in the wake of the Sunday system, resulting in a mild and dry day on Monday with highs in the upper 40s and lower 50s. Meanwhile the next wave currently off the Pacific Northwest coast will quickly approach from the west, spreading another round of rain across central Illinois Monday night into Tuesday. As colder air begins to arrive in the wake of this wave, a brief rain/snow mix may develop along/north of I-72 as the precip ends Tuesday afternoon and evening. 12z Dec 28 models continue to indicate a significant chunk of the bitterly cold airmass just north of Alaska breaking loose and surging southeastward into the Midwest by the middle and end of next week. ECMWF shows 850mb temps dropping into the -10C to -15C range Wednesday through Saturday, resulting in a return to below normal highs in the 20s by the end of the forecast period. Barnes && .AVIATION... (For the 00z TAFs through 00z Sunday Evening) Issued at 524 PM CST Sat Dec 28 2024 A strong low pressure system tracking northeast through the lower Ohio Valley, will spread IFR ceilings north across the central IL terminals tonight, along with RA and MVFR to IFR visibilities, primarily from KSPI-KBMI and points southeast. Northeast winds will increase overnight, veering northwest toward daybreak, with highest gusts of 20-30 kt occuring at KDEC-KCMI. -RA will diminish from the west on Sunday, finally clearing out of KCMI around mid afternoon. Ceilings are forecast to rise to MVFR levels as the rain diminishes. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Marquette MI
647 PM EST Sat Dec 28 2024 .KEY MESSAGES... - Mild temperatures continue through Monday, returning to near normal by New Year`s Day onward. - Accumulating lake effect snow is likely (>70% chance) in the west becoming northwest wind snow belts New Year`s Day through at least Friday, which could lead to difficult travel conditions. && .SHORT TERM /THROUGH TODAY/... Issued at 123 PM EST Sat Dec 28 2024 Water vapor and RAP analysis highlight a 1002mb surface low lifting northeast through Lake Superior as a mid-upper level shortwave presses north. Rain associated with this has continued today, gradually following the surface low. Light reflectivities have been noted on KMQT radar, so suspect additional rainfall for most today has been 0.25 inches or less. Upstream radars KDLH/KGRB shows the back edge of the rain approximately along a line from Ely Minnesota, to the Bayfield Peninsula and Tomahawk in Wisconsin, to near Menominee Michigan. Further upstream, weak ridging and drier air has supported clear skies expanding northeast through central/southern Minnesota and Wisconsin. The warm airmass over the region alongside the abundant moisture has supported temperatures and dewpoints in the 30s to low 40s. There is still some patchy fog out there, but visibility has improved greatly through the day. For the remainder of the afternoon and through 0z this evening, rain, possibily mixed with some snow, will continue lifting northeast and the drier air will continue lifting into the area. Temperatures may drop some after sunset, but are still remain above freezing in this period. && .LONG TERM /TONIGHT THROUGH SATURDAY/... Issued at 407 PM EST Sat Dec 28 2024 Starting tonight, the mid level trough will be negatively tilted over Lake Superior and northern Ontario with the associated sfc low centered north of central Lake Superior. To the south, another trough responsible for today`s severe weather in the Lower Mississippi Valley and Southeastern U.S. is beginning to lift northeast. This will move toward the Great Lakes and merge with a shortwave off the central Rockies for early next week. In the meantime, the trough and sfc low continue lifting north tonight toward Hudson Bay allowing for some weak high pressure to develop overhead. This could yield some fog redevelopment late tonight, especially if there is better clearing early on. The HREF continues to show probabilities of vis dropping to 0.5 mi or less increasing to around 50% for much of the UP by early Sunday morning, so some patchy dense fog is possible. Also, the rain and melting snow today will leave wet grounds into tonight before temps settle into the 20s to low 30s. This could create some slick spots by Sunday morning with some refreezing on sidewalks and roadways. The southern mid level trough will have lifted to southern IL by Sunday morning with a deepening sfc low just out ahead of it over southern IN. Any lingering fog should diminish in the morning hours leaving the rest of the day fairly dry and quiet. Highs again will be warmer than normal in the upper 30s to low 40s with Tds in the low 30s, resulting in additional snowmelt. Later in the day and through Sunday night, the lifting trough and sfc low will make their way over Lower MI and Lake Huron. There is fairly good agreement that associated precip (a rain and snow mix) will graze the eastern CWA with some upslope enhancement along the northeast late Sunday afternoon through Monday morning. Opted to side with better consensus in model guidance of a drier and less snow accumulation solution since model soundings lack the deep moisture and lift. That said, this will warrant additional monitoring as the ECMWF has trended precip westward and also increased some light snow totals into the far eastern counties over the last few model runs. Outside some additional upslope wintry mix over the far northeast, Monday should remain mainly quiet and dry in the wake of the sfc low. Temps will be a bit cooler than Sunday, mainly peaking in the 30s. With clearing in the south central and along the WI/MI state line, some low 40s may be achieved. Quiet weather continues Monday night as clouds increase with a shortwave/sfc low traveling to the south; temps settle into the 20s. From there attention turns to the LES pattern that sets up on Tuesday. The mid level pattern consists of an elongated trough over much of eastern Canada which rotates through the rest of the work week, mainly centered over northern Ontario. At the sfc, the low over Quebec Tuesday morning retrogrades over Hudson Bay while the southern low over the Mid Mississippi moves east toward New England then lifts to Quebec. All the while, sfc high pressure over the lee of the Canadian Rockies gradually builds south into the Plains and eventually the Midwest by the end of the work week. CAA with this brings 850 mb temps down to around - 11C to -13C by Wednesday with lower temps to -18C to -20C for Friday. Snow accumulations look to mainly be confined to the west wind snow belts through Thursday night, with a more northwest component merging in Friday into the weekend. Given the Lake Superior sfc-850 mb delta-ts, some moderate to heavy periods of LES could lead to difficult travel at times New Years Day to the end of next week. Otherwise temps return to near normal around the holiday and slightly below normal by next weekend. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 646 PM EST Sat Dec 28 2024 Conditions have generally improved across the area with MVFR to IFR conditions being reported across much of the area. Ample low-level moisture is present across the area given the recent warm temperatures and rainfall, which will help to bring a return of fog overnight. KCMX will see LIFR conditions develop after 08Z, with the development of fog aided by light winds. While the current TAFs for KSAW and KCMX keep IFR conditions for early Sunday, there is still a 25% chance that one or both terminals could drop to LIFR. In any event, conditions at all terminals will trend to MVFR after sunrise. KCMX will see westerly winds this evening with gusts to 25kts; however, these will die down there after midnight, with generally light winds expected at all terminals during the day on Sunday. && .MARINE... Issued at 426 PM EST Sat Dec 28 2024 A low pressure system has made it just north of central Lake Superior this afternoon and will continue lifting north-northeast tonight with weak high pressure building in behind it. Westerly winds of 20-30 kts are expected this afternoon and evening with a few gale force gusts to 35 kts possible over the east (~20-40% chance). Winds fall to less than 20 kts tonight as the high pressure builds overhead. West winds veer north for Sunday, holding mainly less than 15 kts through the day. Northwest winds then hold around 20 kts or less Sunday night through Tuesday night. Some northwest gusts may approach 25 kts Wednesday through Thursday night. && .CLIMATE... Issued at 309 AM EST Sat Dec 28 2024 Record warm highs and lows at WFO MQT in Negaunee Township (records date back to 1959): Date High Low Dec. 28 42 (1979) 34 (2003) Dec. 29 43 (1979) 31 (2002) && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JTP LONG TERM...Jablonski AVIATION...RM MARINE...Jablonski CLIMATE...
Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
921 PM EST Sat Dec 28 2024 ...New UPDATE... .UPDATE... Issued at 914 PM EST Sat Dec 28 2024 The environment over East TN remains quite stable in the low levels as a warm front is located well to our south, across southern GA to central AL. Convection ongoing in MS is expected to reach our SW counties around 08-09Z, with a weakening trend as it moves east through our area. With a strong LLJ ahead of this line, isolated strong wind gusts of 40-50 mph may be able to mix down to the surface, but the potential for widespread damaging winds is low. For the High Wind Warning, we are starting to see winds increase in the usual mountain locations, with Camp Creek reporting 39 mph and Cove Mountain reporting 34 mph. This will continue to increase in the enxt few hours as the LLJ translates east. No changes will be made to the HW.W. A few small adjustments will be made to PoP/Wx grids to better match current radar and the latest HRRR runs for precip timing. Otherwise, the forecast looks in good shape. && .SHORT TERM... (This evening through Sunday) Issued at 321 PM EST Sat Dec 28 2024 Key Messages: 1. Damaging mountain wave winds are expected tonight into tomorrow across the Tennessee mountains and adjacent foothills. 2. A line of showers and embedded storms is expected to move in around 3 AM EST tomorrow with strong to marginally severe storms possible in the far southern areas. Discussion: Currently this afternoon, troughing is centered to our west with a 120+ kt jet extending from the ArkLaTex region up to the Great Lakes. An area of low pressure is also noted in the ArkLaTex region with severe convection already ongoing. Throughout the evening, troughing will become more and more negatively tilted with the surface low deepening as it moves towards west Tennessee. Strong upper divergence in the right-entrance region of the upper jet will continue to strengthen the already impressive low-level jet. By around midnight, the 850mb jet is expected to be 65 kts or more to our west. As such, decent mountain wave event is still anticipated with no changes to the High Wind Warning expected. Regarding the severe weather risk, the setup will produce an impressively sheared environment, especially in the lower levels. The consensus is for 0-1km shear to be around 40 kts with sufficiently strong deep-layer shear. The main inhibiting factor will be the expected occlusion of the system late tonight into the early morning hours. It should also be noted the extent of cool air moving in from the cold air damming regime to our east. Each updated runs of the high-res model guidance continue to indicate the warm sector likely staying south of our area. Some elevated instability is certainly possible, but the tornado threat is very limited in our area. For the timing, models suggest a line of showers and embedded storms to move in around 3 AM EST and exit to the east by late morning. Based on the overall environment, the main concerns would be some strong winds and possibly small hail with possible later redevelopment. Otherwise, the activity will push off to the east later in the day on Sunday leading to another cool and cloudy day. && .LONG TERM... (Sunday night through next Saturday) Issued at 321 PM EST Sat Dec 28 2024 Key Messages: 1. Rain chances return Monday night into Tuesday with strong winds likely again in the mountains. 2. Progressively colder temperatures are expected mid to late week. Sunday Night through Wednesday At the start of the period, troughing will be in place over the area with the system impacting the short term period having pushed off to the eastern Great Lakes. Initially, some wraparound moisture could keep a few lingering showers in the area, but ultimately the result will be cooler temperatures. Another system will eject out of the central Rockies and deepen fairly rapidly as it moves towards the Ohio and Mississippi River Valleys. The system will track to our north Monday night into Thursday morning, bringing another chance of rain. The environment looks to support a cool rain with temperatures ahead of the system completely above freezing in the lower levels. The strong MSLP gradient and near 50 kt 850mb jet will likely lead to another wind event, especially in the mountains. By Wednesday, the system will be to our east with CAA behind its associated cold front. Lingering moisture and westerly to northwesterly flow will keep chances for snow showers across the mountains. Thursday through Saturday Late in the week and and into the weekend, a troughing pattern will persist across the area with even deeper troughing likely by next weekend. A secondary frontal boundary may move through Friday into Saturday with Arctic high pressure arriving from the northwest. This could produce even more significantly cold conditions, which is supported by very strong negative 500mb anomalies in the ensemble data. Depending on the amount of moisture present, light snow could be possible during this time, but strong subsidence from the high pressure may limit this potential. && .AVIATION... (00Z TAFS) Issued at 613 PM EST Sat Dec 28 2024 TRI and TYS are seeing VFR conditions due to a downslope wind that will increase in strength over the next few hours. This will create LLWS overnight ahead of a line of showers/storms that will cross the area from west to east between 06Z and 12Z. CHA will maintain IFR to LIFR conditions until after the line moves through, with TYS and TRI staying VFR until the line arrives. Gusty winds to 30 kt may accompany the showers. A cig at MVFR levels will likely prevail through the day tomorrow, with gusty SW winds. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 59 54 63 47 / 50 90 70 10 Knoxville McGhee Tyson Airport, TN 62 51 64 48 / 50 90 80 30 Oak Ridge, TN 59 52 63 47 / 30 90 70 30 Tri Cities Airport, TN 65 56 63 45 / 50 80 80 30 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...High Wind Warning until 1 PM EST Sunday for Blount Smoky Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Southeast Monroe-Unicoi. VA...NONE. && $$ SHORT TERM...DGS LONG TERM....BW AVIATION...DGS
Area Forecast Discussion
National Weather Service New York NY
753 PM EST Sat Dec 28 2024 .SYNOPSIS... A warm front will remain nearby through tonight, and then lift north during Sunday. A strong cold front swings through Monday morning. High pressure briefly moves in on Tuesday followed by another low pressure system moving over the area on Wednesday. Low pressure remains over southern Quebec while high pressure builds to the south through the end of the week. && .NEAR TERM /THROUGH SUNDAY/... Hoisted a Dense Fog advisory for the interior portions of the CWA as many locations are near or at 1/4 mile visibility. Preemptively issued a Dense Fog Advisory for the rest of the CWA including NYC and Long Island as dense fog will be possible later tonight. While visibilities may fluctuate through the night, there may be intermittent pockets of fog where visibilities are less than 1/4 mile making for potentially dangerous travel. A stalled out front boundary will remain nearby throughout the night. Synoptically speaking a warm front / stationary boundary, take you pick; should more or less wash out over or just to the west of the CWA. At the same time there is likely to remain a weak coastal frontal boundary in place. Thus, a very light SW flow should prevail, although many stations, especially further inland will register light and var winds much of the time. Closer to the coast and further east look for more of a light southerly flow. This will keep clouds in place along with light liquid precip all night long. The higher probability of light rain will remain over the southern portion of the region with some assistance from any coastal boundary. Otherwise should be a good portion of the night where more northern areas experience a break from organized rain, and mainly some intermittent very light showers or drizzle. Temperatures will average a bit above normal with low cloud cover and low level moisture entrenched. Lows will range in the upper 30s across the interior to the lower and middle 40s elsewhere. During Sunday look for another cloudy and dreary day. Low pressure off to our southwest will begin to spin up with the assistance of positive vorticity advection across the Tennessee Valley and into the Central Appalachians. Ridging over the area out ahead of this system may aid in lifting ceilings a bit for the afternoon. The warm frontal boundary which has been lingering nearby will lift north in response to low pressure developing back to the southwest. As the front lifts north a break in organized light rain / shower activity is likely to take place in the afternoon as RAP and NAM 3km forecast soundings indicate some drying above 1 to 2 kft. Clouds will remain in place with broad isentropic lift increasing later in the day. This may bring back a couple of area of light rain / showers late in the day and early evening. Overall a unsettled day initially, but likely to not be raining for a good portion of the afternoon other than some drizzle. With the warm front lifting north and a more established low level southerly flow look for temperatures to climb well above normal with mainly middle and upper 50s. A couple of spots flirt with 60 in all likelihood, despite all the clouds. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/... The synoptic gradient increases to begin Sunday night as more isopleth / isobar packing is evident in the surface and lower mandatory level forecast analysis. This is in response to developing low pressure lifting northeast into the Great Lakes with its frontal system extends to the east a pivots through the Appalachians. The frontal system will then reach the coast and our areas towards daybreak. Out ahead of it look for the low chance of a few showers in weak isentropic lift during the evening, but much of the first half of the night appears to be dry. The LLJ (60 kts or so at 2 kft) really cranks up just before and towards midnight, reaching its peak towards 09z to 12z Mon. This strong warm advection in the column will focus moderate to briefly heavy rain along and just ahead of the approaching boundary. PoPs increase quickly for the second half of the night. Lifted indices drop below +5 which raises the possibility of embedded quasi-convective elements. Thus, a quick pulse of heavier rain just before and approaching daybreak is looking like a good bet. Questions remain as to how much of the strong southerly flow in the form of gusts can mix down to the surface just ahead of the boundary. Dew points are likely to surge to near 50 or in the lower 50s late Sunday night / early Monday morning just ahead of the front. Steady or slowly rising temperatures are likely in the stronger warm advection pattern. During Monday look for the boundary to cross the metro on either side of 12z, and likely to clear far eastern portions of the area by midday. The winds switch quickly behind the boundary to more a westerly component (W / WSW). This will bring in drier and cooler air, but this next air mass is more pacific than cP in nature. Clearing takes place quickly during the mid to late morning from west to east. It will be unseasonably mild with record highs for the date in the lower and middle 60s. Current forecast values are short of the record temperatures, but would not be surprised if forecast numbers trend a little higher on the next couple of NWP cycles. Thus we could get close to a few records on Monday on a W to WSW wind which will be gusty at times. Total QPF through the near and short term combining the two disturbances together yields 0.75 to 1.25 inches liquid equivalent, all in the form of rain. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... By Monday night, the cold front pushes east with some subtle ridging over the area allowing for surface high pressure to build into the region from the southwest into Tuesday. This will allow for dry conditions with generally light winds and relatively clear skies Monday night into early Tuesday. By mid-day Tuesday, clouds begin to move in from the southwest ahead of the next developing low pressure system. A shortwave digging into the Tennessee Valley and Southeast US will allow for a developing low pressure system to move into the area by Tuesday evening and into early Wednesday. There remain some differences in the exact placement of the low pressure system as it shifts generally overhead Tuesday night into early Wednesday. Regardless, rain showers are expected to begin to overspread the region from southwest to northeast early Tuesday evening. A widespread rainfall is then expected during much of the overnight as the energy of the low pressure shifts to a developing coastal low that pushes off the New England coast into Wednesday. The low continues to intensify as it occludes over southern Quebec into Thursday and Friday. This will result in generally dry conditions and breezy NW flow through the end of the week, though some remnant rain or snow showers can`t entirely be ruled out in the wake of the departing low on Thursday. Persistent strong NW flow will result in strong CAA through the end of the week. High temperatures by Friday and Saturday are expected to be only in the 30s. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... A weak boundary lingers across the area overnight as a warm front approaches from the south. The warm lifts north of the area from late morning into the afternoon. A cold front then approaches from the west late Sunday night. Widespread LIFR/IFR conditions are forecast overnight with low ceilings, fog, and rain or drizzle. Improvement is likely late morning Sunday through Sunday afternoon as the warm front pushes further north. Best chance for improvement will be along the coast with a good chance of becoming VFR. However, farther north and west of the NYC terminals, improvement will be slower and may never even make it to KSWF. This improvement should be temporary before conditions worsen again Sunday night with an approaching cold front. Winds will be light and variable overnight. On Sunday, coastal wind speeds increase during the afternoon where S gusts over 20kt possible late. Wind shear becomes increasingly likely,especially heading into Sunday night. NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty... Extent of improvement late Sunday morning into the afternoon will be dependent on how far north of the terminals the warm front gets. Amendments are likely through the period with the timing of category changes and wind shifts. OUTLOOK FOR 00Z SUNDAY THROUGH THURSDAY... Sunday night into Mon Morning: -RA/RA and IFR conds. LLWS likely. S winds with gusts up to around 30kt. Monday afternoon: Becoming VFR with W winds. WSW winds G15-20kt. Tuesday: Mainly VFR, likely MVFR late Tue/Tue Night in -RA. Wednesday: MVFR or lower in -RA likely, improvement to VFR possible by afternoon. W winds in the afternoon G20-25kt. Thursday: Mainly VFR. W winds G25-30kt. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Sub small craft conditions take place tonight and through most of Sunday. For tonight some patchy fog is likely across portions of the waters, with areas of fog also possible which may restrict visibilities at times. Issued a Marine Dense Fog advisory for the sheltered waters near land as visibilities through the night may regularly be 1 NM or less. During Sunday afternoon a S wind will increase resulting in small craft gusts for the western ocean late in the day. Then largely from west to east Sunday night small craft conditions develop from west to east. Ocean seas also climb during Sunday night into Monday morning. Seas will likely remain elevated on the ocean through Monday evening with small craft conditions prevailing. The nearshore waters should transition to sub small craft conditions during Monday afternoon. SCA conditions continue on the ocean waters with wave heights 5-7 feet into Monday night. Conditions become marginal with wave heights near 5 feet on Tuesday but very quickly expected to be well within SCA criteria on the ocean waters as winds and waves increase ahead of the next low pressure system that is poised to move over the area on Wednesday. Behind the low, a strong NW wind with gusts upwards of 30 kt develops on all waters resulting in SCA conditions by Wednesday night and into Thursday. There is a low chance for gales on the ocean during this timeframe. && .HYDROLOGY... At this time there are no hydrologic concerns through next week. && .TIDES/COASTAL FLOODING... There continues to be a widespread distribution in the NYHOPS / Stevens TWL forecast, primarily for the western LI south shore bay locations into the first half of next week. The cycles that are garnering attention are the early Mon and Wed cycles driven by a new moon phase into Monday. With the larger uncertainty overall a widespread minor coastal flood benchmark approach is on the table, with minor to moderate potential for some of the western LI south shore bay locations, more so for the Mon AM cycle. The uncertainty at this time centers around any wind wave contribution and how much any southerly flow can mix down to the surface with a series of low pressure systems that track nearby and just to the west. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Dense Fog Advisory until 7 AM EST Sunday for CTZ005>012. NY...Dense Fog Advisory until 7 AM EST Sunday for NYZ067>071. Dense Fog Advisory from midnight tonight to 7 AM EST Sunday for NYZ072>075-078>081-176>179. NJ...Dense Fog Advisory until 7 AM EST Sunday for NJZ002-004-103- 104. Dense Fog Advisory from midnight tonight to 7 AM EST Sunday for NJZ006-105>108. MARINE...Dense Fog Advisory until 7 AM EST Sunday for ANZ331-332-335- 338-340-345. Small Craft Advisory from 10 PM Sunday to noon EST Monday for ANZ331-335-338-340-345. Small Craft Advisory from 10 PM Sunday to 6 PM EST Monday for ANZ332. Small Craft Advisory from 6 PM Sunday to 6 PM EST Monday for ANZ350-353. Small Craft Advisory from 4 PM Sunday to 4 PM EST Monday for ANZ355. && $$ SYNOPSIS...JE/MW NEAR TERM...JE/MW SHORT TERM...JE LONG TERM...MW AVIATION...DW MARINE...JE/MW HYDROLOGY...JE/MW TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Raleigh NC
830 PM EST Sat Dec 28 2024 .SYNOPSIS... A stalled front across central NC will gradually move northward early Sunday morning. Meanwhile, low pressure will develop and substantially deepen from the lower MS Valley to the Great Lakes. A trailing cold front will move east across the region Sunday night. Following Pacific high pressure will migrate across and offshore the Carolinas Monday and Monday night. && .NEAR TERM /THROUGH TONIGHT/... As of 830 PM SATURDAY... * Sharp contrast in temperatures across the area * Rain early, tapering off after midnight * Fog possible across the western Piedmont. The wedge front remains stationary across the Piedmont this evening, resulting in a sharp contrast in conditions across the forecast area. Earlier today, areas generally south and east of I-85 saw temps rise well into the 60s and 70s this afternoon with only a few light showers. On the other hand locations to the west barely broke out of the mid/upper 40s with low clouds/fog through most the day. 00Z and 01Z surface obs show the front lingering between I-85 and US- 1, but it should begin the slow process of retreating northward overnight. A stronger surge in warm advection and a strengthening LLJ will help the front move northward, resulting in relatively early minimum temperatures. Temps will remain mild in the upper 50s/60s to the east, whereas temps in the Triad are likely to begin rising overnight. Only made minor adjustments to temperatures with the evening update based on observational trends. Meanwhile, light stratiform rain continues to develop and move northward along and just to the cool side of the stalled surface boundary. PoPs will remain in the 70-90 percent range through the evening/overnight hours to account for this precip, with lower values (20-30 percent) elsewhere. Rainfall amounts will be light, generally less than a quarter of an inch. The past few runs of the HRRR indicate an additional round of light rain should develop around 09Z and move through the area although confidence in this is low. In terms of fog potential, the rain currently across the western Piedmont should move through the area and taper off shortly after midnight. There is likely to be a several hour period where fog (possibly dense) is possible across the Triad before it`s scoured out as the front retreats northward through the area before daybreak. I`ll keep the mention of fog in the forecast with the idea that a Dense Fog Adv may be needed for parts of the area at some point late tonight. && .SHORT TERM /SUNDAY THROUGH MONDAY/... As of 214 PM SATURDAY... * Slight Risk of severe storms across most of Central NC into Sunday evening * Breezy south-southeasterly winds gusting between 30 and 40 mph during the afternoon to early evening hours of Sunday along/ahead of convection * Turning cooler Monday, but still above seasonal normals The overall pattern has largely remained consistent for the period Sunday into early Monday. A negatively-tilted upper trough will progress from the MN/TN Valley into the lower Great Lakes and Mid- Atlantic region. At the surface, a surface low over the MN/TN Valley is forecast to deepen to ~ 988 mb once it reaches the eastern Great Lakes. As this happens, a cold front will progress through our forecast area late Sunday night. Ingredients for showers and storms remain in place for Sunday afternoon and evening, including PW`s near the climatological maximum of 1.3 to 1.5 inches, strong lift with the trough/front, and abundant vertical shear. The uncertainty still lies in the amount or degree of instability that can be realized along and ahead of the front. The latest 12Z HREF and HRRR suggest that the best overlap of instability and shear should coincide over the southern Piedmont, Sandhills and southern Coastal Plain. Most CAMs suggest that while some isolated showers may be present across our western zones Sun morning, the main action will come in the afternoon to evening hours, roughly from 11 am to 8 pm from west to east. As such temperatures should manage to be some 15-20 degrees above normal in the mid 60s in the west to the lower 70s in the east. Several of the CAMs, most notably the HRRR, suggest a pre-frontal line of convection will advance eastward in the afternoon to early evening. A mixed convective mode is possible with this line, with a QLCS and semi-discrete cells possible, most favored in the far southern Piedmont to Sandhills region, where there is better overlap of CAPE/shear. One uncertainty is that the initial line appears to move through ahead of the axis of instability. Behind the initial line, some CAMs suggest another batch of showers and storms could move through, with perhaps a better overlap of CAPE/shear, although at this point we will be near convective minimum. Regardless, SPC has retained a slight risk across all but our far eastern counties. The main risk will be damaging wind gusts. An isolated tornado is still possible, but most favored where CAPE/Shear coincide across the southern Piedmont and southern Sandhills. Along and ahead of convection, low-level winds exceeding 40+ kts combined with downward momentum transfer will support breezy southerly winds of 30 to 40 mph. These appear to be most favored along and east of US-1. Convection should exit our CWA around 10 pm or so as the front progresses eastward. Overnight lows will be cooler but still warm for this time of year in the mid 40s to near 50. By Monday, westerly flow will take over aloft, trending to southwesterly by early Tue ahead of our next trough settling into the TN valley. High pressure over northern FL and GA will weaken ahead of a surface low reaching southern IL. While there will be some CAA behind the front, the airmass will still be well above normal. As such, highs will reach the low 60s in the west and upper 60s in the east. We should stay dry most of the night, with lows cooler in the low to mid 40s under a light southeasterly wind. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 300 PM Saturday... Rain chances return on Tuesday (New Year`s Eve) as another low pressure system moves through the Ohio River Valley. Isolated to scattered showers are expected to move through the region starting NYE morning through the evening. In the afternoon, the atmosphere may destabilize, which would allow for a few rumbles of thunder east of US1. Highs on Tuesday are expected to be in the 60s into low 70s, while lows for NYE should be in the low to mid 40s. Wednesday after the cold fropa, we should return to cool northwesterly flow. High temperatures will drop to the 50s on Wednesday, with lows in the upper 20s to mid 30s. On Thursday, a reinforcing dry Arctic front will reach the region, dropping temperatures further. Thursday and Friday highs should be in the mid 40s to low 50s with lows in the mid 20s to low 30s. Another blast of dry Arctic air is expected to reach the region on Saturday, dropping temperatures further, with highs in the low to mid 40s and lows in the low to mid 20s. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... As of 710 PM Saturday... High confidence in LIFR/IFR at GSO and INT through 12Z Sunday, with a period of rain expected between 01Z and 05Z, followed strengthening winds aloft and the potential for LLWS. Ceilings will gradually lift after 12Z ahead of a line of showers and isolated thunderstorms expected to move through the area between 16-18Z. Strong winds will develop immediately ahead of the showers and may be even stronger with the heaviest showers. Low ceilings and some additional showers may then linger through 00Z. MVFR ceilings at RDU may lower to IFR tonight while some showers move north through the area, though confidence is below average. Expect and overall lifting of ceilings Sunday morning, with strong southerly winds developing and gusting to as high as 30kt ahead of a line of showers and isolated storms that should impact RDU between 18Z to 21Z. Similar conditions are expected at FAY and RWI, though with MVFR and MVFR more likely tonight and increasingly southern winds that may gust to 20kt by 12Z and then increase to 30kt. There is also a better chance of thunderstorms at FAY and RWI with the line of convection between 18-00Z. Outlook: Lingering low-level moisture behind the passing showers and storms will maintain a risk of IFR-MVFR ceilings until a cold front crosses the region Sunday night-Monday morning. A weak and fast moving frontal system will favor a chance of a few showers/storms and brief restrictions again Tue-Tue night. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Leins/MWS NEAR TERM...Leins SHORT TERM...Kren LONG TERM...Helock AVIATION...BLS/MWS