Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/14/23

National Weather Service Albany NY
932 PM EST Fri Jan 13 2023 .SYNOPSIS... Cloudy and brisk conditions will continue overnight in the wake of the storm system and cold front. A few snow showers and flurries are possible over the western Adirondacks and the Capital District. Over the weekend, dry weather is expected, with seasonable temperatures and breezy conditions remaining in place. Temperatures will return above normal next week with a few rain or snow showers possible on Tuesday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... .UPDATE as of 930 pm EST...Low pressure continues to move northeast across New Brunswick into the Gulf of Saint Lawrence this hour on the latest RAP. Cold advection continues across the forecast area with temps continuing to drop in the wake of the cold front. Localized convergence continues in the wake of the cold front with winds out the north/northeast at KGFL, northerly at KRME, but KNYO (Johnstown) is westerly and KALB varying from north to northwest. A persistent narrow corridor of light snow or snow showers continues to impact portions of the Saratoga Region and the Capital District. The NYS Mesonet sfc convergence plot shows the best low-level convergence the past few hours from eastern Albany Co. north/northwest into eastern Schenectady, southern Saratoga and eastern Fulton Counties. Some hints of Mohawk Hudson Convergence based on the CSTAR research, but the activity is displaced a bit further to the west of the Hudson River Valley. Hints of a secondary sfc trough or boundary moving across the region with the northerly flow from ALY northwest at some of the observational sites. We increased the PoPs into the high chance category and raised snow amounts to around an inch or so across portions of southern Saratoga County, with lesser amounts south with dustings to a few tenths of an inch towards Albany. The Ballston Spa NYS mesonet camera shows the persistent snow and it looks like about an inch has fallen. An NWS employee near Malta reported 1.1" of snowfall at 9 pm. This activity according the 3-km NAM and to a lesser extent the 3-km HRRR should diminish over the next few hours. Some light dustings to a few tenths of an inch of snow are possible along the northern and central Taconics. Mostly cloudy to cloudy conditions will persist overnight with the mid and upper level trough over the region. Some light snow amounts are possible over the western Adirondacks and possibly the southern Greens in the north/northwest flow aloft. Lows still look on track with 20s and some mid and upper teens over the southern Dacks and southern Greens. There will be enough of pressure gradient in place between the departing storm and high pressure north of the Great Lakes to keep brisk north to northwest winds in place through the overnight. A few gusts up to 25 mph can`t be ruled out, especially over the high terrain. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Dry weather is expected through the short term period. With the upper level trough still overhead, skies will continue to be fairly cloudy through much of Saturday. There may be some breaks for some parts of the area by afternoon, but skies will generally be mostly cloudy. With the the clouds around and cooler temps in place aloft (850 hpa temps down to -3 to -7 C), highs will only be in the low to mid 30s for valley areas (20s in the high terrain). It still will be somewhat breezy at times, as a decent pressure gradient remains in place. A little more clearing is expected for Saturday night, which should allow for temps to be a little cooler than Friday night. Lows will probably be down in the teens to low 20s for most areas. It will still be fairly breezy so wind chill values will be down in the single digits to low teens through the overnight hours. On Sunday, a large cutoff upper level low will be located off the eastern seaboard. This will be allowing a surface low to develop, although it will be fairly far offshore. While it will be too far away to bring precip into our area, it will continue to keep a stiff pressure gradient in place. Northerly winds will be 10 to 15 mph, with some gusts of 20 to 30 mph possible. Skies will be fairly clear, although eastern areas will have the best chance of seeing some more clouds from the coastal low. Temps will be fairly chilly, although seasonable, with valley highs in the low to mid 30s. High terrain areas will continue to see temps in the 20s. Winds will be finally decreasing for Sunday night with skies remaining fairly clear. Lows will be down into the teens for much of the area. && .LONG TERM /MONDAY THROUGH FRIDAY/... The extended forecast period opens with dry weather across the forecast area for MLK Day with a mid and upper level ridge over NY and the East Coast with a cut-off low near Nova Scotia and northern New England and an upstream trough digging into the Central Plains. Surface high pressure will be centered to the north over north- central Quebec with a chilly north/northwest flow aloft and temps being near to slightly above normal with highs in the upper 20s to lower 30s over the mtns, and mid 30s to around 40F in the valley areas. Some mid and high clouds increase from the south and west Monday night with a decoupling of the winds and some radiational cooling briefly with lows in the teens north and east of the Capital Region with low to mid 20s to the south. Low pressure approaches from the Great Lakes Region Tuesday into Wednesday. The warm front to the system and a short-wave will bring some snow and a brief mix possibly early Tuesday morning, before the precipitation changing to rain in the afternoon, as temps rise into the 30s to lower 40s. The cyclone track north of the forecast area puts us on the warm side, so mainly rain is expected with this system though some light snow accumulations are possible north of the I-90 corridor. The upper trough axis and cold front move through Tuesdy night into early Wednesday with some rain and snow showers. Some lake effect snow showers and flurries are possible Wednesday morning for the western Adirondacks with light snow accumulations. Lows will be in the mid 20s to lower 30s, and highs on Wednesday should be near normal to slightly above normal, as some flat ridging occurs a head of the next system moving out of the southern Plains and lower MS River Valley. A brief period of tranquil weather is possible late Wednesday afternoon into Wednesday night as clouds increase from the south and west again, as low pressure moves into the Midwest and Great Lakes Region. Some over running pcpn moves into the forecast area with a decent baroclinic zone ahead of the cyclone. Lots of spread in the medium range guidance and ensembles with some scenarios indicating secondary cyclogenesis occurring near the Delmarva Region/NJ Coast moving into Thursday evening, which could allow for an extended period of snow or mixed precipitation. We have gone with a rain/snow scenario at this point with the primary low upstream dominating, as temps rise above normal into the 30s to lower 40s. Unsettled conditions linger into Friday with a slight to low chance of rain/snow showers with cyclonic flow persisting aloft with low pressure centered over s-central Quebec. Temps will likely finish the week still above normal for most the forecast area. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Through 00Z Sunday...Conditions are currently MVFR across the region with bkn-ovc cigs at 1-3 kft and unrestricted vsbys. A band of light showers is dissipating as it slides southward in the Hudson Valley. Flurries ended at GFL between 23-00Z and may briefly reduce vsbys at ALB/PSF through 01Z. Otherwise, bkn-ovc MVFR cigs are likely to persist at ALB/GFL/PSF while low VFR cigs are likely at POU overnight into Saturday morning. Slow clearing and lifting cloud bases will trend terminals toward VFR conditions, particularly at ALB while GFL/PSF may be slower to clear and maintain MVFR cigs later into Saturday. Winds at currently out of the north to northwest at 5-10 kt with gusts of 15-20 kt possible at all terminals through the overnight. The wind direction will increasingly turn out of the north Friday evening, with gusty northerly winds expected to persist through the remainder of the TAF period to 00Z Sunday. Outlook... Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Martin Luther King Jr Day: No Operational Impact. NO SIG WX. Monday Night: No Operational Impact. NO SIG WX. Tuesday: Moderate Operational Impact. Chance of RA. Tuesday Night: Low Operational Impact. Slight Chance of RA...SN. Wednesday: No Operational Impact. NO SIG WX. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Frugis/Wasula NEAR TERM...Frugis/Wasula SHORT TERM...Frugis LONG TERM...Picard AVIATION...Main
Area Forecast Discussion
National Weather Service Boston/Norton MA
955 PM EST Fri Jan 13 2023 .SYNOPSIS... A frontal wave of low pressure may cause rain in southeast MA and a mix of rain and snow in northeast MA overnight. Mainly dry Saturday. Surface low pressure over the ocean well south of the 40N/70W benchmark early Sunday tracks east then pivots north toward Nova Scotia on Monday. This may produce accumulating snow in southeast MA. A warming trend begins Tuesday and continues through much of next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 10 PM Update... Slow moving cold front continues to move southeast at this hour, but is progressing slower than previously forecast, with all observation sites reporting temperatures above freezing at the latest ob. Several sites across far southeast MA are still reporting temperatures near 50F. 00Z guidance indicated that there would be an increased chance in precipitation overnight, with the NAM especially aggressive on the potential for some light freezing drizzle. Several factors indicate that the NAM is an outlier solution including ground/pavement temps that are still well above freezing, very light perception overnight, and a very slow trend in cooling temperatures, thus, expecting that any freezing drizzle/sleet potential will be very isolated, mainly to the communities in the higher terrain of Middlesex/Essex counties NW of Boston. At this time, given the NAM is the true outlier solution, and sufficient meteorological evidence supporting that notion, a winter weather advisory is NOT being considered. However, a short fused SPS during the early to mid morning hours is possible if we see a broad area of frozen precipitation develops; leading to slick surfaces. With that said, a persistent drizzle currently is and will continue to fall over the next few hour as dry air moves in aloft, with saturation from the surface to about 800mb. Even so, dry air will try to push in from the NW as the cold air stalls off the coast, bringing the drizzle potential to an end by the early AM hours. Drizzle is expected to be replaced by light rain/snow showers as the precipitation shield backs in from the east overnight. Precipitation will be mainly limited to the I-495 corridor, east across eastern MA and the Cape. 8 PM update... Cold front has moved into southeast MA and will be exiting the coast in a few hours. Light rain and drizzle has formed behind the front in Worcester and Middlesex Counties in central MA. Satellite imagery shows a baroclinic leaf moving into southern New England now, with cooling cloud tops. Latest hi-res model guidance has shifted west with its precipitation shield for the overnight hours. The NAM 3km shows some light icing in northeast MA; the HRRR shows a deeper cold layer and light sleet in northeast MA; the RAP shows categorical probabilities along the entire eastern MA coast shortly after midnight. In collaboration with GYX, have upped PoPs to 30-45 percent in northeast areas of MA through the overnight hours. Precipitation type ranges from a rain/snow mix at Boston to snow and sleet in Essex County. A light dusting is possible. Precipitation exits the region to the northeast by early to mid morning Saturday. The next shift will have to assess the rapidity of temperatures falling and decide if a short-fused Advisory will be needed for any freezing drizzle or light freezing rain. Previous discussion... Cold front in the CT River Valley is moving slowly eastward, given mid level flow remains from the SW to NE. Thus, temps in the 50s across eastern CT/RI and central-eastern MA late this afternoon will fall into the 30s behind the front tonight. Deeper cold air westward, and will yield lows in the mid to upper 20s across western CT into western/central MA overnight. It will feel colder as blustery NNW winds 10-15 kt gusting up to 25 mph at times, in the post frontal airmass as it overspreads the region. Although, only seasonably cold for this time of year. Mainly dry weather tonight, however, you can see in the water vapor loop, a baroclinic leaf forming along the NC coast and adjacent waters. That`s a frontal wave forming on the boundary, and may clip the outer Cape and Nantucket with a period of chilly rain overnight. Otherwise, dry weather prevails. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... 335 PM update... Saturday... Frontal wave east of Cape Cod exits to the NE. Short wave ridging develops over SNE, providing dry weather. Although, with frontal boundary just offshore, moist NNE flow along with some upslope into the Worcester Hills, will yield lots of clouds. Best chance for sunny breaks should be in the CT River Valley and points westward. Chilly airmass combined with lots of clouds will only yield highs 35- 40, highest temps over Cape and Islands. It will feel chilly given brisk NNE winds around 15 mph, gusting up to 25 mph across Cape Cod and the Islands. Again, seasonably cold for mid Jan. Saturday night... Potent vertically stacked low develops off the NC coast. Mid level warm air wraps cyclonically around the mid level circulation, pivoting toward southeast MA daybreak Sunday. Model soundings suggest column cold enough for snow over southeast MA, possibly mixed with sleet as warm layer advects around 800 mb. Boundary layer may be warm enough over Cape Cod and Islands for a rain/snow mix. Precip intensity appears light, at least at the onset. Elsewhere, dry cold weather prevails. NE winds noticeably increase as system intensifies offshore. May eventually need wind advisories for southeast MA with NE winds potentially gusting 40-50 mph. Seasonably cold Sat night, with lows in the 20s, to low/mid 30s over Cape and Islands. It will feel colder given increasing NE winds. && .LONG TERM /SUNDAY THROUGH FRIDAY/... 405 PM update... Highlights... * Ocean storm may be close enough to produce accumulating wet snow over far southeastern MA Sunday into early Monday. * Warmer temperatures begin Tuesday and last through next week. Sunday into Monday... Still expecting a mid level closed low off the the mid-Atlantic coast to move slowly northeast Sunday and Monday, taking on a slight negative tilt. At the surface, a rather tight low pressure system located about 175 miles south of the 40N/70W "Benchmark" will be slowly deepening, as it travels along the edge of the Gulf Stream. We now have increased confidence that the precipitation shield from this storm will reach far enough northwest to affect Cape Cod and the Islands as well as interior southeast MA and perhaps even reaching the I-95/I-495 corridor for a time. The precipitation type and amounts are still very much in question, however. Models indicate very cold temperatures at 925 mb...near -7C...presumably from diabatic cooling processes. There is a bit of a warm layer above 800 mb. Thus, sleet is a possibility, especially over far southeast MA, mainly north of the Cape Cod Canal. Surface temperatures will be above freezing during the day Sunday throughout southeast MA with upper 30s on Nantucket. Rain is expected to start over the Islands then the shield spreads northwestward and mixes with sleet and snow late in the afternoon. Onshore winds over Cape Cod...from the N to NNE...will add to the delay in accumulation because sea surface temperatures are in the 40s. However, by Sunday evening and during Sunday night, as temperatures cool, accumulations are more likely on Cape Cod and interior southeast MA. Snow to liquid ratios will be low, on the order of 8:1 (a wet snow), which will limit accumulations. But, we cannot rule out a period of some ocean-effect enhancement, with a 12-degree differential (-7C at 925 mb and +5C ocean temp). For now, have indicated 1-2 inches of accumulation from about Hull to Plymouth and as far west as Brockton/Bridgewater. Model 10:1 amounts are much higher than this, but notable that the snow depth changes are in line with our forecast and with WPC`s forecast. The 12Z run of today`s ECMWF indicates that snow also develops from the northeast and spreads SW into northern MA as far west as Fitchburg and Worcester during the day on Monday, as the system heads toward Nova Scotia and becomes negatively tilted. Am not forecasting this as yet. This forecast will need to be monitored, since it will likely be changing somewhat. North to north-northeast winds will gust to 30-40 mph along the east coast of MA Sunday into Monday and a Gale Watch has been posted through at least Sunday. Monday night through Friday... Weak high pressure will bring a short period of clearing Monday night and Tuesday, with highs reaching the lower to mid 40s. A weak short wave disturbance traverses the region Tuesday night. It could generate a hundredth or two of precipitation, mainly north of the Mass Pike. Can`t rule out some light freezing rain in the highest terrain in the slopes of the Berkshires or northern Worcester Hills. A quiet day is expected Wednesday with partly cloudy skies and temperatures climbing to 45 to 50. Another storm approaches from the southwest on Thursday with a good chance of rain that could start as a flake or two of snow at the onset in western areas. Rain ends early Friday. Highs in the 40s. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 01z update... Thru 12z...Medium confidence. MVFR ceilings overnight. Rain is possible, mixing with snow and/or sleet at KBOS toward daybreak. Light snow or freezing drizzle may develop in northeast MA after 06Z. VFR/MVFR and dry weather for much of CT into western-central MA. Light WNW winds becoming north late and increasing up to 25 kt Cape Cod and Islands. Saturday...high confidence. Mainly dry weather with MVFR/VFR conditions,IFR possible outer Cape Cod and Nantucket. North winds 15-25 kt, strongest over Cape Cod and Islands. Saturday night...high confidence on trends, lower confidence on exact timing of lower cigs/vsbys with precip late. VFR with increasing NNE winds, 20-30 kt with gusts up to 40 kt possible toward Sunday morning across Cape Cod and Islands. MVFR with rain or snow possible late for Cape Cod. KBOS Terminal...High Confidence in TAF. Wind shift from SW to W around 00z. MVFR should prevail during the evening push. KBDL Terminal...High Confidence in TAF. Wind shift from south to west around 20z, and then lifting from MVFR to VFR. Outlook /Sunday through Wednesday/... Martin Luther King Jr Day: Mainly VFR, with local IFR possible. Windy with local gusts up to 30 kt. Slight chance SN. Monday Night: VFR. Breezy. Tuesday: VFR. Breezy. Chance FZRA, slight chance RA. Tuesday Night: Mainly VFR, with local MVFR possible. Breezy. Chance FZRA, slight chance RA. Wednesday: VFR. Breezy. Wednesday Night: Mainly VFR, with local IFR possible. Breezy. Slight chance SN. Thursday: RA likely, chance SN. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 8 PM update... *** NE Gales possible Sat night & Sunday *** Tonight...high confidence. Wind shifts from SW to WNW with gusts up to 20 kt. Improving vsby with the wind shift. Then vsby lowering in rain overnight, mainly for the waters east of Cape Cod and Nantucket. Saturday...high confidence. Dry weather with frontal boundary offshore. North winds 15-25 kt. Saturday night...high confidence. NE winds increase 25-35 kt, with gusts up to 40 kt possible toward daybreak Sunday. Dry weather, except toward daybreak Sunday when rain and/or snow will arrive from the south. Outlook /Sunday through Wednesday/... Martin Luther King Jr Day: Strong winds with local gusts up to 30 kt. Rough seas up to 14 ft. Chance of rain, chance of snow. Areas of visibility 1 to 3 nm. Monday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Rough seas up to 11 ft. Tuesday through Tuesday Night: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain. Wednesday through Wednesday Night: Winds less than 25 kt. Seas up to 5 ft. Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft. Rain likely. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Gale Watch from Saturday evening through Sunday evening for ANZ231>235-237-250-251-254>256. Small Craft Advisory until 4 AM EST Saturday for ANZ235-237. Small Craft Advisory until 11 PM EST Saturday for ANZ250- 254>256. && $$ SYNOPSIS...Nocera/GAF NEAR TERM...Nocera/KS/GAF SHORT TERM...Nocera LONG TERM...GAF AVIATION...Nocera/GAF MARINE...Nocera/GAF
Area Forecast Discussion
National Weather Service Burlington VT
1022 PM EST Fri Jan 13 2023 .SYNOPSIS... Any lingering light snow across the region will become terrain focused overnight with some minor accumulations in the mountains possible by morning. In addition, a few lake enhanced snow showers and flurries are possible over the Champlain Valley as colder air moves over the warmer waters. Weather looks quiet this weekend with at or slightly below normal temperatures anticipated. && .NEAR TERM /THROUGH SATURDAY NIGHT/... As of 1016 PM EST Friday...Ample low level moisture across much of area this evening. Cold advection well underway. Still have a few snow showers/flurries, especially in the Champlain Valley. Overall, going forecast in good shape. A Special Weather Statement has been issued to highlight the slippery conditions tonight that the snow left behind. Previous discussion... As system continues to pull away, precip wl become trrn focused overnight, as favorable upslope flow btwn 925mb and 850mb develops. However, at the same time moisture in the favorable DGZ is decreasing and becoming confined to the lowest 3000 ft, resulting in the potential for patchy freezing drizzle. Did mention above 2000 ft acrs the dacks, but kept out of VT mtns attm as lift/moisture profiles are slightly better. Did note some high res guidance showing as northerly flow becomes aligned and 925mb temps drop btwn -10C and -12C aft 06z, we could see some additional light Lake Champlain snow showers/flurries in the CPV. Have tried to incorporate this detail into grids, any accumulation would be light and under 0.5". Temps fall back into the teens most spots with a few lower 20s in the warmer valleys. On Saturday...the challenge wl be clouds and amount of clearing as soundings indicate moisture trapped below inversion btwn the sfc and 850mb. Also, anticipate some lingering upslope flurries/light snow showers possible. Did note the 18z HRRR clips the eastern cwa with some light snow from offshore area of low pres, which wl be passed along to the evening crew. Always challenging to determine how quickly this dissipates and skies clear, but the general idea clouds hold the longest acrs the trrn and east side of the CPV looks reasonable, while some clearing develops on the downslope areas of the western CPV and lower CT River Valley. Highs on Saturday look to be at or slightly below seasonable norms with readings in the 20s. Saturday night the focus for the fcst wl become temps as 1029mb sfc high pres noses into northern NY, including the SLV. This results in drying profiles and lighter winds, combined with fresh snow pack could produce some below zero values. Have noted some very cold guidance with readings approaching -10F in northern NY, but given uncertainty on winds/clouds we wl trend toward the 10-25% NBM guidance for now. This general idea supports lows near zero western cwa to mid teens CT River Valley. I would anticipate additional adjustments wl be needed in future forecasts. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 354 PM EST Friday...Chances of precipitation are nil during this period as strong sinking motions will be present on the western periphery of the big upper level low over the western Atlantic Ocean. Near the surface, northerly flow will keep us on the cold side of normal, especially with ridging aloft helping maintain a pretty low mixing depth; forecast soundings show an inversion at about 1000 feet above ground. So the northern Champlain Valley should wind up colder than most spots, including the higher terrain, with highs mainly 20-25. With winds in the 15 to 20 MPH range, it will feel chilly with wind chills topping out in the single digits above zero throughout much if not all of the day in the breezier spots. Overnight, clouds may arrive from the east across easternmost Vermont as the ocean low pressure area retrogrades, but skies over most of the region likely stay clear. However, the pressure gradient will remain substantial, with this flow keeping temperatures from really tanking despite the dry low level air, so seasonably cold lows in the single digits to low teens looks reasonable. Again, higher elevations look relatively mild with 850 millibar temperatures potentially nearing freezing at times as pockets of relatively warm air aloft circulates counterclockwise from the aforementioned, potentially strong low pressure system. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 354 PM EST Friday...This looks like a fairly active period with three systems potentially impacting the area. We continue to see a pattern strongly favoring above normal temperatures on average, and also leaning towards above normal precipitation per Climate Prediction Center 6-10 day outlook for the period. The latest NAEFS shows an anomalously moist air mass associated with yet another potential late week storm system for our region associated with another wave ejecting from the deluge in the western US. Monday-Monday night Eyes will be on the big low pressure area lingering to our east, as high latitude blocking pushes it northwestward towards eastern Maine early in the week. As it gyres northward, moisture wrapping counterclockwise around the system may reach into Vermont on Monday. Low chances of measurable precipitation at this time, and only across eastern Vermont, given global model consensus. However, the ENS (European ensemble) shows better much better odds than the GEFS (GFS ensemble) and GEPS (Canadian ensemble) data. Along those lines, the latest ECMWF and NAM12 do show a period of light mixed precipitation and/or snow in eastern Vermont on Monday. NBM probability of weather type based on wet bulb temperatures aloft does show snow is the most likely precipitation type and so all snow is forecast. However, if precipitation does occur during a period with temperatures aloft ticking above freezing, there is some chance of a wintry mix which will need to be monitored if chances of precipitation trend upward in the next couple of days. Overall, no big impacts expected with this system for our region, even if greater chances of precipitation shift farther to the west. With continued northerly flow near the surface, temperatures remain on the cold side but moderate a bit compared to Sunday. Temperatures will peak in the mid and upper 20s in most spots. Tuesday-Wednesday Better chances of light and widespread precipitation arrives from the west by Tuesday afternoon associated with a weakening shortwave trough traversing the Great Lakes. Given the flat/west-southwest oriented upper level pattern, moisture will be limited. However, precipitation should be relatively enhanced downwind of Lake Ontario, which continues to be open with nearly zero percent ice cover. As such, greatest chances of precipitation Tuesday night into Wednesday (40-50%) are across southern St. Lawrence County into southern Franklin County and northernmost Essex County, NY. With the low pressure area tracking roughly across northern New York and Vermont, temperatures ahead of the system may warm enough to produce some mixed precipitation yet again, with a smattering of freezing rain chances indicated in southern portions of the region where a higher likelihood of a warm nose creating a melting layer aloft. While thermal profiles are unsurprisingly a bit all over the place at this stage, model agreement on cooling temperatures aloft on Wednesday as we get on the backside of the low pressure area is strong. While precipitation chances currently diminish quickly during the day, this is a period to watch for potential upslope snow showers if the low pressure system winds up being stronger than the current consensus shows. Thursday-Friday A sharp ridge will support a period of dry conditions initially, but then another late week storm, with potential for heavy precipitation, becomes likely to impact our region. This could be another messy storm as we will still be lacking a dome of polar air overhead to support a sure bet snow event. However, amongst model guidance at this time, both the GEFS and GEPS do favor a storm track south of the forecast area which allows for mainly snow; in fact, the ensemble mean snowfall is roughly 4 inches in both ensembles across much of south central Vermont and Essex County, New York, with amounts tapering to 2 inches farther north. However, based on low probabilities of >4" snowfall, there is large spread in the guidance typical of this time range, so we will have to wait and see trends in the coming days. For snow lovers, the consensus storm track currently looks to be to our south, especially if you discount the EPS. As such, the most likely precipitation type is snow across the region for majority of the Thursday afternoon through Friday timeframe, but is far from a lock. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Through 00Z Sunday...Primarily MVFR conditions across the forecast area, with SLK and RUT the exceptions with LIFR and VFR respectively. Stations should remain MVFR overnight with some brief periods of IFR before settling at MVFR again during the day Saturday. MSS should see decreasing cloud cover Saturday morning and with that, VFR conditions after 15z. Expect northwest winds 5 to 15 knots at most sites thru the period. Outlook... Saturday Night: VFR. NO SIG WX. Sunday: VFR. NO SIG WX. Sunday Night: VFR. NO SIG WX. Martin Luther King Jr Day: VFR. NO SIG WX. Monday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Tuesday: VFR. Slight chance SN. Tuesday Night: MVFR/IFR conditions possible. Chance SN, Slight chance FZRA. Wednesday: Mainly MVFR, with areas IFR possible. Slight chance FZRA, Slight chance SN. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Taber NEAR TERM...HTS/Taber SHORT TERM...Kutikoff LONG TERM...Kutikoff AVIATION...Taber/Verasamy
Area Forecast Discussion
National Weather Service Quad Cities IA IL
513 PM CST Fri Jan 13 2023 ...AVIATION UPDATE... .SYNOPSIS... Issued at 200 PM CST Fri Jan 13 2023 Some clearing is noted across central Iowa into north central Missouri, which has progressed into some of northeast Missouri. However, much of the region remains blanketed by stratus. This has limited the temperatures to the mid/upper 20s to lower 30s, with northerly winds around 10 to 15 mph making it feel more like the teens and lower 20s. Earlier we`ve noted a few flakes or snow grains across portions of the area, but of more interest is what looks to be a microscale band of very light snow persistent over a small section of lower Rock Island County into central Mercer County, which may be a result of lake influence (Lake George) with a favorable northerly wind trajectory and inversion height around h850. && .SHORT TERM...(This evening through Saturday) Issued at 200 PM CST Fri Jan 13 2023 Key Message: - Cloud trends and impacts on temperatures are the main challenge. Details: Despite the stratus layer thinning, it remains stubborn to budge for much of the area. With surface ridging building into the region tonight owing to weak low level flow confidence is very low on extent of any clearing for tonight. Guidance is largely struggling with the stratus, but the HRRR seems to be doing the best with the clearing into central Iowa and north central/northeast Missouri currently, and it supports the idea of the stratus lingering tonight with some additional clearing possible into parts of eastern Iowa. With this idea of keeping clouds much of the area I have bumped up lows a bit and going at or above 90th percentile of NBM with mid 20s, except for far west/southwest where best potential for some clearing and have colder lows in the teens to around 20. Some flurries are possible as well especially this evening with a weak wave passing, as noted in some upstream obs this afternoon. Saturday, as the surface ridge shifts east by afternoon winds will turn southerly and begin to increase. The increased mixing through the cloud bearing layer should help foster breaks and at least partial sunshine in the afternoon. Have opted to keep highs at 50th percentile of NBM with mid 30s to near 40, except for the far south where higher confidence exists on more solar insolation and have highs in the lower to mid 40s. .LONG TERM...(Saturday night through Friday) Issued at 200 PM CST Fri Jan 13 2023 Key Messages: 1) An active long term period is expected, with a few chances for precipitation and many gloomy days to come. 2) Per CPC 6-10 day outlook, we continue to see favorability for above normal temperatures and precipitation. Discussion... While we will see increasing cloud cover ahead of an approaching trough, Sunday is geared to be quite pleasant. Increasing low level southerly flow will allow temperatures to rise into the mid-upper 40s. Other than some gusty surface winds, a quiet weather day is expected. Monday, a weak surface low will bring widespread rain to the forecast area. While widespread, this will be far from a heavy rainfall event. This system will bring a persistent light rain and lead to a gloomy start to the work week. How much rain can we expect? Probabilistic guidance favors up to a quarter inch of rain, with chances decreasing as we approach a half inch. Currently, we are looking towards 0-500 J/kg of MUCAPE, which will be more than sufficient to bring some thunder to the area. If we get embedded thunderstorms, some locations may see localized heavier rainfall. Temperature-wise, we are looking at another beautiful day, with those along and south of Interstate 80 in the 50s. Winds die down Monday evening ahead of the front. Thus, we may see some fog potential with the residual moisture and a weak source of convergence. Although, after midnight, winds pick up and may kill any further fog development. We are still looking at a storm that may impact the region mid-late week, but we continue to have a lot of uncertainty. The EURO and CMC continue to bring this system right over our forecast area, bringing all forms of precipitation, especially wintry precipitation. The only trend to note with these two models is the fact that they have trended a few degrees warmer on the last couple runs. Warmer temperatures will lead to some precipitation type issues, if we end up getting the storm. The recent GFS has taken a completely different turn, leaving much of the area dry and the bulk of precipitation out east. With that said, the GFS Ensemble brings precipitation to the area, making its deterministic run an outlier. So, like we said, still very uncertain. After this system passes, we continue to see hints at a potential quick hitting system over the weekend. Now, that is too far out to go into any details. Overall, we are just in an active pattern where it seems like we have a storm system impacting the midwest every 2-3 days and above normal temperatures that continue. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 511 PM CST Fri Jan 13 2023 Persistent low clouds are likely to hang on all night, before south winds and clearing spreads over the area Saturday in the mid to late morning. Cigs should be in the 1200 to 2000 ft range overnight, with good visibility. Winds will be mainly light and variable until 15-16Z, then southerly at 10 kts. && .CLIMATE... Issued at 239 PM CST Fri Jan 13 2023 Record Warm Low Temperatures for January 16... Dubuque...36 in 1980 Moline...42 in 1913 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...McClure SHORT TERM...McClure LONG TERM...Gunkel AVIATION...Ervin CLIMATE...Gunkel
Area Forecast Discussion
National Weather Service Gray ME
1035 PM EST Fri Jan 13 2023 .SYNOPSIS... Quite a bit of cloud cover will remain across the region tonight and Saturday as an area of low pressure develops off the Mid Atlantic Seaboard and moves across the Gulf of Maine. This low may bring some mixed precipitation across coastal areas Saturday morning and afternoon. Clouds and a few scattered snow showers may cling to the eastern portions of the forecast area for Sunday and Monday due to this nearly stationary low pressure system. Another area of low pressure will cross the Northeast Tuesday into Wednesday bringing a few snow showers to the region. High pressure follows for Thursday with another area of low pressure for Friday. && .NEAR TERM /TONIGHT/... 1035 PM Update...Performed minor tweaks to the forecast to account for observed trends in T/Td and radar. Temperatures are reaching the freezing mark across the Lakes region this morning; fortunately this is coming with some mixing and dry air, so suspect pavement drying will be more efficient here than in the mountains... where an SPS has been issued due to potentially icy roadways into early Saturday morning. Light echoes continue to track into and along the coast... with surface stations occasionally reporting light precip... mostly rain, but also unknown precip (likely a mix) as well. 830 PM Update... Made a few adjustments to the forecast. First, loaded in observed temperatures and dew points and made only very minor tweaks to overnight/morning trends using latest HRRR which seems to be tracking things well enough. Also bumped up wind gusts a touch through the evening as cold/dry advection behind the departing wave allows for some mixing... and decreased fog chances after midnight with the front slipping offshore. Finally, added some drizzle mention with light echos on KBOX lofting north this evening. Biggest change to the forecast was to pull PoPs upward along the coast Saturday morning with hires guidance continuing to produce a swath of very light precipitation (more below). Previously... A few lingering showers are possible this afternoon, and possibly a rain/snow mix across the far north into tonight, but precip is pretty much done for the time being with the better moisture and forcing having exited into eastern and northern ME. However, plenty of cloud cover and patchy fog will linger into tonight. For those that warmed up into the 40s and 50s today, north to northwest winds will cool temperatures back into the 30s tonight, while the rest will go from temperatures into the 30s back into the 20s. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... 830 PM Update... Biggest change to the forecast was to pull PoPs upward along the coastal plain and into the interior Saturday morning with hires guidance continuing to produce a swath of very light precipitation there. As the inherited forecast suggested... snow is more likely the further inland you go where temp profiles are favorable, and rain toward the coast, where temperatures won`t dip below freezing until later tomorrow... a transition period of light freezing rain or sleet would result in the middle. Still not keen on sounding the alarm for impacts, since pavement temperatures are still quite warm... QPF is very light... and temperatures will be slow to cool below freezing anyway. Will monitor this for trends toward a more impactful solution. Previously... Another low pressure will move across the Gulf of Maine and toward Nova Scotia early Saturday, potentially bringing another round of precip toward coastal ME and perhaps into the Coastal Plain from the morning into the afternoon hours. Plenty of cold air in the lowest levels and some warm air remaining aloft suggest that some of this could fall as freezing rain or sleet, especially toward the Midcoast and Augusta regions. While any ice amounts are expected to be a few hundredths of an or less, it could still produce some slippery roadways and surfaces. Elsewhere and otherwise, mostly cloudy skies will continue with north to northwest occasionally gusting to around 20 mph. Temperatures won`t recover much at all from the morning start with southern areas mainly in the lower 30s while northern areas stay in the 20s. High pressure building over Quebec will bring some cooler and drier air southward into the area Saturday night, which should bring some partial clearing of skies. Lows in the teens are expected across the north while southern areas have lows in the lower to mid 20s. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Overview: Complex, unique system to near the coast through late weekend and early next week. This could bring a mix of precipitation types, some creating slick travel conditions Sunday into Monday. Brief lull arrives Tuesday before a shortwave pushes through Tues night. Broad area of low pressure finally trends east Wed and Thurs before another low advances into the eastern CONUS late week. Details: Focus for the long term is on a large area of unsettled weather in the open Atlantic through the end of the weekend into early next week. Overall guidance trend of backing precipitation further west towards the coast and across some inland portions continues for today’s runs. This creates a tricky forecast for QPF and precip types resulting from a striated lower thermal profile. Upper trough will slowly begin to tilt negative Sunday, with the base off the SE coast. An area of fairly stagnant air develops over western portions of the CWA, slowly drying through much of the mid and low levels. This area of dry air is apparent on soundings and WV sim satellite, and could prove to bring the mountains and portions of western New England a almost cloud free day. Of contrast will be increasing cloudiness along the coast. This is closer to moisture that rounds the trough into a conveyor belt pointed towards Nova Scotia. IVT plots keep the strongest moisture advection well off the coast, but should be noted that some is assisted westward by the TROWAL. While current trends support the increasing chances of precip and warm air aloft, QPF is still rather light on the NBM and ensemble guidance. This could be attributed to the steady flow of N/NE air at the surface that will be aiding cool, dry air into the low levels and surface. This creates a rather tricky thermal profile with abundant warm, moist mid levels from the east...and cool, dry air to the west and at the surface. Top CIPS analogs point towards events in 1981 and 1979 for comparison, one of which saw plenty of mixed precip reports throughout Maine and portions of New England. Current forecasts keep this system a bit further east than the top analog, and this is reflected by lesser QPF over land...especially points in New England west of central NH and MA in our current forecast. Portions of western and southern NH and far SW ME may see very little precipitation due to the dry air mass being slowly displaced westward. Have decided to keep the forecast rain/snow based at this time...but mixed precipitation is a good bet given model profiles that favor sleet and freezing rain along the coast and towards the ME capitol region. Dry air at the surface may temper QPF and keep precip light, but will need to monitor trends where areas of precip may train. The first thousand feet or so could mix well below the stout inversion, with gusty N winds Sunday into Monday...slowly shifting NW. A brief lull pushes across the CWA Tuesday as the broad low slowly retreats east. This comes right before a shortwave merges with main jet across the central US Tuesday night, bringing the chance for some showers. However, some of this moisture may be muted due to downsloping in the Whites. With another high moving in, the next low looks to affect the Northeast into late next week. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/... Short Term...A few showers linger into this afternoon, but in general precip has come to an end for the time being. Some patchy fog will linger into tonight, but think the primary restriction will be the ceilings. IFR ceilings are likely to continue into this evening at RKD and AUG with primarily MVFR elsewhere, possible low-end VFR at times. There may be some additional improvement to low-end VFR tonight, but then most guidance brings MVFR ceilings back overnight and through Saturday. There is also the possibility of some mixed precipitation in the PWM/AUG/RKD corridor Saturday morning and afternoon. A gradual return to VFR conditions is expected Saturday night. Long Term...VFR begins Sunday, with cigs lowering from east to west Sunday night into Monday. MVFR to IFR is possible towards KAUG/KRKD. This may be accompanied by FZRA/PL/SN. Elsewhere there may be a hard edge to lower cloud bases and near SKC or high cirrus. && .MARINE... Short Term...Winds will veer to the northwest and then north tonight as a low pressure moves across Maine, which will be followed by another low pressure moving across the Gulf of Maine early Saturday. Solid SCA conditions will be in place tonight and Saturday, which will further deteriorate Saturday as the gradient tightens been a low off the Mid Atlantic and high pressure over Quebec. A Gale Watch has been put up for Saturday night. Long Term...A extended period of gales through Monday and perhaps into Monday night over at least the outer waters. Winds should be N, shifting NW as low pressure slowly moves towards the Canadian Maritimes. Waves of 7 to 10 ft continue into Tuesday morning. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 11 PM EST Saturday for ANZ150>154. Gale Watch from Saturday evening through Sunday evening for ANZ150>154. && $$ UPDATES...Casey NEAR/SHORT TERM...Combs LONG TERM...Cornwell

.SYNOPSIS... Issued at 258 PM CST Fri Jan 13 2023 -An upper trough and closed low may spread a wintry mix of light precipitation across the forecast area Sunday night into Monday. -A second system may impact southern portions of the forecast area Tuesday into Wednesday. && .SHORT TERM...(This evening through Saturday night) Issued at 258 PM CST Fri Jan 13 2023 An upper ridge will remain over western Nebraska tonight. Will see an increase in high cloudiness. Lows tonight will be in the low to mid 20s. The latest HRRR and RAP show no indication that fog will develop tonight. On Saturday, a surface trough will remain in place across the high plains of Colorado and eastern Wyoming. Winds 5 to 15 mph, with relatively warm temperatures aloft, highs will range in the 40s across the area. Skies will range from partly to mostly cloudy through the day. Saturday night, an upper trough will move into Utah and Arizona later tonight with increasing southwest flow aloft across western Nebraska. This will bring an increase in high cloudiness. .LONG TERM...(Sunday through Friday) Issued at 258 PM CST Fri Jan 13 2023 The base of the upper trough will advance across Colorado and northern New Mexico by late Sunday afternoon. A closed low is forecast to develop over the tri state Sunday evening and advance into eastern Nebraska by Monday morning. The models, including the NAM, GFS and ECMWF have shown and increase in QPFs, albeit light. A comparison of soundings favor light rain Sunday evening, followed by a wintry mix of rain, freezing rain or snow Sunday night into Monday morning. The main concern with this system will be if any freezing rain occurs, or light snow across the western or northern Sandhills. Little accumulation of freezing rain or snow is expected at this time. However if low level moisture does increase, minor impacts could occur. This system should lift northeast of the area with dry conditions Monday night. The next system is forecast to move across portions of the region Tuesday night through Wednesday. The GFS has trended weaker and considerable farther south, and is now more in agreement with the ECMWF and Canadian model. Model consensus is for the H5 low to track from Texas panhandle 12Z Wednesday into eastern Kansas/north central Oklahoma by 00Z Thursday. This now places the precipitation across Kansas and extreme southern Nebraska. The latest NBM has lowered pops to 30 percent from I80 south. Confidence has increased that this system will keep a southern track. Another upper trough is forecast to drop southeast from the Rockies into the Central and Northern Plains Thursday into Friday. Current NBM forecast is just a slight chance of light snow across north central Nebraska. Regarding high temperatures next week, Sunday highs will range in the 40s, cooling into the low 30s to low 40s Monday and Tuesday. Mainly 30s for highs Thursday and Friday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 520 PM CST Fri Jan 13 2023 Persistent low stratus over central Nebraska will continue to erode, with widespread VFR and increasing high cloudiness anticipated overnight. Winds remain from the southwest through tomorrow, at around 5 to 15kts. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Roberg SHORT TERM...Roberg LONG TERM...Roberg AVIATION...Brown
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
339 PM PST Fri Jan 13 2023 .SYNOPSIS...13/208 PM. A series of storms will bring periods of rain and mountain snow to the area through Monday. High surf will continue across the beaches through at least Saturday evening and again next week. && .SHORT TERM (TDY-MON)...13/206 PM. A somewhat complicated pattern over the next 3-4 days as a series of storms move through the area. A weak system moved through earlier today and brought light rain to western SLO and Santa Barbara Counties. Models at one time indicated that this area of showers would progress through the remainder of the area overnight tonight but more recent HRRR runs have scaled back on this. Radars do show some light showers moving into Central Santa Barbara County this afternoon but it`s looking less likely that it will survive much farther east as the core of the storm lifts northeast. At best probably just some sprinkles or very light showers tonight. The next system still on tap for Saturday and Saturday night and looks more or less on track in terms of timing and amounts. Lighter warm-frontal showers expected to develop at some point in the morning or early afternoon as south to southwest flow increases. In these cases showers often develop sooner than models expect, but in any case the primary focus will be on the main frontal band which is expected to come through between late afternoon for SLO and Santa Barbara Counties and evening for LA/Ventura Counties. It`s during this period when rain rates will be at their highest. There have been a few hi res models today that have shown one hour rates as high as 0.80"/hr, though most of them have been closer to a half inch and that seems to be the most likely scenario. With these rates impacts will be slightly greater than what would normally occur with a storm of this magnitude since the ground is still fairly saturated from previous rain, but still just on the minor side, including small mud slides in the foothills and mountains, and typical minor road flooding. Amounts still projected to be around an inch for coast/valleys and 1.5-3 in the mountains. Snow levels will be at or above 7000` for most of this event so accumulations will be confined to higher elevations. For this reason have opted to go with a winter weather advisory rather than a winter storm warning as impacts for most of the mountain areas will be at elevations with very few people. The mountain resorts on the LA/San Bernardino County should do well with accumulations, especially at 8000` and above where a foot or more could fall. Rain and snow expected to taper off Saturday night as the flow quickly shifts to northwest. During this short period into Sunday morning snow levels will fall to around 5000` as the colder air moves in, however accumulations down to that level are expected to be minimal at best. There will be typical gusty southerly winds ahead of the front through Saturday night. The winter weather advisory will cover the winds in the LA/Ventura mountains. The Antelope Valley and interior SLO County will also see advisory level winds at times. A break in the weather most of Sunday until later in the afternoon and evening when the next storm arrives. This one has less moisture to work with but is a little colder and has the potential for convection at the end of it. Ensembles have been consistently producing about half the amount of rainfall, though if thunderstorms do develop (best chances later Monday into Monday night) rainfall totals could end being similar in those locations. The colder storm will bring accumulating snow to lower elevations (mainly 5000` and higher), but overall snow amounts will be lower than the with the Saturday system. There`s a 10-20% chance that lingering moisture and northwest flow following the system could cause some light snow accumulations down to around 4000` late Monday night into early Tuesday. .LONG TERM (TUE-FRI)...13/221 PM. Models now trending dryer for Tuesday as the Monday system exits to the east and northwest flow takes over. Most ensemble solutions show a dry pattern the rest of the week with periods of gusty north to northwest winds. Then shifting to Santa Ana`s later in the week into next weekend. && .AVIATION...13/2338Z. At 2315Z, there was neither a marine inversion or marine layer at KLAX. Overall, low to moderate confidence in 00Z TAF package. Through this evening, moderate confidence in MVFR CIGs north of Point Conception and VFR conditions south of Point Conception. Late tonight through Saturday afternoon, front will sweep across the area, bringing light to moderate rain with MVFR to IFR conditions. However, timing in flight category changes and steady rain is low. KLAX...Low to moderate confidence in 00Z TAF. There is a 30% chance of MVFR CIGs 02Z-13Z. After 13Z, high confidence in development of rain with CIG/VSBY restrictions, but low confidence in timing of rain and flight category changes (categories will vary from MVFR to IFR). Moderate confidence in east to southeast winds around 8 knots 13Z-22Z. KBUR...Low to moderate confidence in 00Z TAF. There is a 30% chance of MVFR CIGs 02Z-13Z. After 13Z, high confidence in development of rain with CIG/VSBY restrictions, but low confidence in timing of rain and flight category changes (categories will range from MVFR to IFR). && .MARINE...13/116 PM. For the Outer Waters, moderate to high confidence in the current forecast. Small Craft Advisory (SCA) conds are expected at least through late Sunday night due to SCA level seas and/or winds as more Pacific storms move into the area. There will then be a 40%-50% chance of SCA levels winds and seas Monday through Wednesday. There is also a 40%-50% chance of gale force gusts for the northern zone (PZZ670) Sunday night and Monday. Peak seas during the forecast period are expected Monday night with seas up to 15-20 feet. For the Inner Waters north of Point Sal, moderate to high confidence in the current forecast. SCA conds are expected at least through late Sunday night due to SCA level seas and/or winds. There will then be a 40%-50% chance of SCA levels winds and/or seas Monday through Wednesday. Peak seas during the forecast period are expected Monday night with seas up to 16 to 19 feet possible. Large, breaking waves will be possible at harbor entrances through Saturday, and again Monday afternoon through Tuesday. For the Inner Waters south of Point Conception, moderate to high confidence in the current forecast. SCA conds are expected at least through late Sunday night due to SCA level seas and/or winds. There will then be a 40%-50% chance of SCA levels winds and/or seas Monday through Wednesday. Peak seas during the forecast period are expected Monday night with seas up to 9 to 12 feet possible. && .BEACHES...13/128 PM. A couple of storm system moving into the area will bring a 15-18 foot west swell with a 17-19 second period into the coastal waters through this evening then slowly subside through Saturday night. Therefore, a HIGH SURF ADVISORY is in effect for San Luis Obispo, Santa Barbara, and LA County Beaches through Saturday evening. A HIGH SURF WARNING is in effect for Ventura County Beaches due to the westerly component of this long period, large swell. There is less confidence in the LA County beaches reaching 15 feet and Central Coast beaches reaching 20 feet, so Advisories will continue. With another storm system coming in Monday into Tuesday, there is a likelihood that the advisories/warnings will be needed again by early next week. Warning level surf can cause beach erosion along with a threat of minor coastal flooding at the time of high tides, and damage to coastal structures and piers. For more details about the High Surf Advisories and Warnings, please refer to the Coastal Flood Advisory product (LAXCFWLOX). && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Winter Weather Advisory in effect from noon Saturday to 3 AM PST Tuesday for zones 53-54. (See LAXWSWLOX). Wind Advisory in effect from noon Saturday to midnight PST Saturday night for zone 59. (See LAXNPWLOX). High Surf Advisory in effect until 10 PM PST Sunday for zones 87-340-346-362-364. (See LAXCFWLOX). Wind Advisory in effect from noon to 9 PM PST Saturday for zones 345-353. (See LAXNPWLOX). High Wind Watch in effect from Saturday afternoon through Saturday evening for zones 345-353. (See LAXNPWLOX). High Surf Advisory in effect until 10 PM PST Saturday for zones 349-350. (See LAXCFWLOX). High Surf Warning in effect until 3 PM PST Saturday for zone 354. (See LAXCFWLOX). PZ...Small Craft Advisory in effect until 3 AM PST Monday for zones 645-650-655-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PST Sunday for zone 670. (See LAXMWWLOX). && $$ PUBLIC...MW AVIATION...RAT MARINE...Sirard BEACHES...Sirard SYNOPSIS...MW Experimental Graphical Hazardous Weather Outlook at:
Area Forecast Discussion
National Weather Service Morristown TN
1018 PM EST Fri Jan 13 2023 ...New UPDATE... .UPDATE... Issued at 1009 PM EST Fri Jan 13 2023 The forecast still remains on track with the northwest flow snowfall underway. The main change was a slight increase in PoPs in the central and northern Valley over the next couple of hours based on recent radar trends. Temperatures were also raised very slightly based on the latest HRRR and recent trends with lows still set to be in the 20s to near freezing. Most places in these Valley areas are seeing snowfall but likely not measurable. Based on the limited data we have so far, the highest places in the Tennessee mountains and southwest Virginia have already seen several inches of snow with even some drifting snow. The message still remains the same with no other changes made. && .SHORT TERM... (This evening through Saturday) Issued at 256 PM EST Fri Jan 13 2023 Key Messages: 1. Snow showers become more widespread in coverage this evening and begin top taper off to flurries late tonight. 2. Clearing conditions Saturday with lingering flurries in the mountains through early afternoon. Discussion: WV imagery and observations show that the low-level moisture has arrived with increased coverage of snow showers. Steep lapse rates with colder air aloft will create some heavier bands of snow across the area through the evening. Significant accumulations are expected across the higher elevations of the mountains with a foot or two of snow possible across the highest terrain above 5000 feet elevation. A Winter Storm Warning continues for the higher elevations of the East Tennessee mountains. A Winter Weather Advisory continues for the higher elevations of southwest Virginia an the Cumberland Plateau where snow may result in some minor travel impacts through the evening and overnight hours. Overall, most areas along the plateau through southwest Virginia should receive between 1 and 3 inches of snow with locally higher amounts across the highest terrain such as High Knob and the Clinch Mountains above 3000 feet. We have extended the Winter Weather Advisory to also cover the mountains of Polk County and Cherokee and Clay Counties in southwest North Carolina. With the angle of the NW/NNW wind and saturation within the DGZ, efficient orographic snow is expected across the higher elevations of Polk and southwest North Carolina. Overall, 1 to 3 inches of snow is expected with locally higher amounts across the highest terrain. In addition, gusty winds are expected to continue across the higher terrain with some gusts up to about 35 mph this afternoon and evening. Across the valley, temperatures will remain too warm for much accumulation this evening, but as temperatures drop overnight, some minor snow accumulation will be possible. We will issue and SPS to account for this. In general, only a dusting of snow is expected for most valley locations, but localized ridgetops and areas that experience a heavier snow band may have up to 1 inch snow accumulation. While accumulations are minor, some localized travel issues could develop, especially on secondary and back roads of the valley. Late tonight and Saturday morning, drier air begins to move in with lingering orographic snow showers and rime ice possible across the higher elevations of the mountains. Upper-level troughing and surface high pressure increasing across the area will lead to a clearing sky through the afternoon with temperatures below normal. && .LONG TERM... (Saturday night through next Friday) Issued at 256 PM EST Fri Jan 13 2023 Key Messages: 1. Gusty north winds and temperatures in the teens to possibly single digits will bring wind chills down to below zero over the higher elevations Saturday night. 2. Unsettled pattern through the long term with chances of rain Mon/Tue and again on Wed/Thu. 3. Windy conditions across the Mountains Monday night and especially for Wednesday night and Thursday. Discussion: For Saturday night, clear sky, cold air and continued breezy northerly winds will produce wind chills below zero across the higher elevations. For Sunday through Monday morning, ridging surface and aloft will moderate temperatures and produce mostly clear sky. For late Monday, Monday night, and Tuesday morning, an upper trough will move across the western Great Lakes with plenty of isentropic lift across the Tennessee valley as the low-level jet strengthens. Isentropic lift and large scale forcing will produce widespread showers over the area. GEFS and ensemble ECMWF agree with 0.3 to 0.5 inch of QPF over much of the area. The associated frontal boundary moves south of the area. The southwest low-level jet of 50-55 knots will produce windy conditions across the mountains but the trajectory is not favorable for a mountain wave event. For Wednesday through Thursday, another stronger system moves out of the plain states for mid to late week. The jet structure is quite strong along with isentropic lift over the boundary just south of the region. Depending on the extent of convection developing along the Gulf stealing moisture pulling northward, this system could produce a round of heavy rainfall. NAEFS GEFS tables showing some high climo percentiles for PW and 850mb moisture transport with this system. && .AVIATION... (00Z TAFS) Issued at 610 PM EST Fri Jan 13 2023 Scattered snow showers will continue tonight, especially near TYS and TRI. Overall, MVFR conditions are expected at these sites with a variation between MVFR and VFR at CHA. Within any heavier snow shower, reductions to below MVFR ceiling and/or visibility is likely. While snow showers will gradually diminish by the morning hours, VFR conditions will be slow to return on Saturday, especially at TRI. MVFR is likely to continue at least into the afternoon hours at the two sites with northerly to northwesterly flow prevailing at all of them through the period. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 31 44 27 51 / 10 10 0 0 Knoxville McGhee Tyson Airport, TN 29 40 23 47 / 40 10 0 0 Oak Ridge, TN 29 41 24 48 / 40 10 0 0 Tri Cities Airport, TN 27 36 20 45 / 40 20 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...Winter Weather Advisory until 7 AM EST Saturday for Cherokee- Clay. TN...Winter Weather Advisory until 7 AM EST /6 AM CST/ Saturday for Bledsoe-Campbell-Claiborne-East Polk-Morgan-Northwest Carter-Scott TN-Sequatchie. Winter Storm Warning until 7 AM EST Saturday for Blount Smoky Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Southeast Monroe-Unicoi. VA...Winter Weather Advisory until 7 AM EST Saturday for Lee-Russell- Scott VA-Washington VA-Wise. && $$ SHORT TERM...JB LONG TERM....DH AVIATION...BW
Area Forecast Discussion
National Weather Service Las Vegas NV
716 PM PST Fri Jan 13 2023 .SYNOPSIS...The next impactful system will bring more substantial rain, snow, and wind to the area over the weekend, especially Saturday evening and overnight. Dangerous mountain travel is likely Saturday and Saturday night in the Sierra, Whites, and Spring Mountains. A weaker but colder storm will move through Monday into Tuesday. The weather patten is then expected to shift, which will bringing drier and colder weather for the second half of the week. && .UPDATE...Shortwave that is lifting northeast across the southern Sierra this evening forecast to weaken as it quickly moves northeast over the Great Basin. Mammoth Lakes CA is reporting light snow currently. Would expect similar conditions south along the southern Sierra into Inyo County. This will be followed by another weak disturbance sliding over the Mojave Desert tomorrow morning. HRRR suggests some light showers potentially developing on the Spring Mtns with this feature between 5 am and 8 am. More impactful system arrives later Saturday and continues through Saturday night. Quieter Sunday as HRRR shows decent break between systems with maybe a few showers persisting in Lincoln and Mohave Counties, near the Utah border. Forecast looking fine. && .PREV DISCUSSION...106 PM PST Fri Jan 13 2023 .SHORT TERM...Tonight Through Saturday Night. Light precipitation will be possible at times through tonight in the Sierra, though snow amounts should remain light as only a brief increasing in moisture is forcing as this first wave moves through very quickly. Outside of the Sierra, not expecting much, if any, precipitation with just abundant cloud cover continuing to blanket the region. On Saturday, anomalous moisture will overspread the region. Widespread anomalously high PWATs of almost 200% of normal in place by 00Z SUN. During the day o Saturday, forcing will be weak and diffuse so while precipitation will be possible in most areas at some point by Saturday afternoon, amounts will be light and impacts due to rain or snow will be limited. The exception will be in the Sierra, Whites, and Spring Mountains. With upslope flow in addition to the weak forcing, expecting moderate to heavy snow at times Saturday afternoon. WSSI shows moderate impacts due to winter weather on the mid-elevation areas, and major impacts at the peaks. Travel will be difficult into Spring Mountains Saturday afternoon- HREF shows high probabilities for over 1in/hr snowfall rates Saturday afternoon and evening. Anyone planning to head to Mount Charleston on Saturday should consider canceling plans or need be prepared for dangerous winter road condition. The main trough swings through the region Saturday night. With high moisture still place, widespread precipitation is likely Saturday night. The moderate to heavy precipitation will be possible in Lincoln and Mohave counties, as well as parts of San Bernardino County that includes areas on the I-15, as well as continued moderate to heavy precipitation in the Sierra and Spring Mountains. Up to a foot of snow is possible in the Spring Mountains, which will be in additional to the 4 to 6 inches of snow they see during the day. Snow levels will fall to around 5000ft with the precipitation after about 10 PM Saturday night. With the heaviest precipitation expected after 10PM in Lincoln County, increasing confidence for impactful snow north of Pioche including on highway 93. Issued a Winter Weather Advisory for Lincoln County for Saturday night into Sunday morning in case anyone would be driving and so people were aware they may wake up to a few inches of snow by Sunday morning. Otherwise, no changes were made to the winter headlines. Winds will increase Saturday night as the system moves through. A decent belt of 700mb winds sets up along and south of the I-15. Some pf the probabilistic data shows possible impactful wind gusts over 40MPH, especially in the western Mojave Desert, however the wind forecast on other models don`t agree. With precipitation moving in and because the ids are moving through during a timer period thats not as favorable for winds to mix down to the surface, held off an issuing any wind headlines at this time. San Bernardino would be the best chance for seeing impactful winds Saturday night, with lesser chances in southern Clark and most of Mohave County. .LONG TERM...Sunday through Thursday. After a brief break Sunday afternoon and Sunday night, second shortwave trough sets its eye on the region Monday-Tuesday. This will be a colder system with lower snow levels which may bring some impacts to Highway 395 in the Owens Valley, as well as roads across south central Nevada and northern Mohave County. As the trough moves inland, associated AR forecast to slide by well to our south impacting the area from San Diego County south and eventually southern Arizona. So with less moisture am counting on stronger dynamics and areas of frontogenesis which could lead to localized banding of higher precipitation in Lincoln, Clark and Mohave Counties. Additional snow accumulations will collect on our already decent snowpack in the southern Sierra and Spring Mountains. Also considered a Winter Weather Advisory for Lincoln County, but after discussion with WFO LKN, chose to defer to the day shift. More uncertainty late week as a few simulations suggest the next trough dropping in across the area from the northwest Thursday. If that materialize, probably more of a wind machine, but still be accompanied by some showers. && .AVIATION...For Harry Reid...Winds will remain light and follow typical diurnal variations into Saturday morning. By Saturday afternoon, winds will increase out of the south with gusts up to 25kts possible at times. High clouds will remain over the terminal today and tonight before CIGs fall to around 15kft by mid-day tomorrow. A few showers will be possible tomorrow afternoon into Sunday morning, which will likely bring CIGs down to around 5kft at times. For the rest of southern Nevada, northwestern Arizona, and southeastern California...Overall, light winds following normal diurnal variations will continue into tomorrow morning. By tomorrow afternoon, gusty southwest winds will increase at the Las Vegas Valley TAF sites, with gusts up to 30kts possible. Gusty winds can also be expected at KDAG during the afternoon and evening. Scattered showers will spread across the region on Saturday, bringing CIGs down to 5kft or lower, especially at the Vegas Valley sites and KBIH. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ UPDATE...Pierce SHORT TERM...Nickerson LONG TERM...Pierce AVIATION...Planz For more forecast information...see us on our webpage: or follow us on Facebook and Twitter