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

Area Forecast Discussion
National Weather Service Binghamton NY
955 PM EST Sun Jan 22 2023 .SYNOPSIS... A winter storm will impact the region tonight into Monday afternoon. A few light snow showers will persist into Monday night before a brief break Tuesday, another potent winter system will impact the area Wednesday into Thursday. && .NEAR TERM /THROUGH MONDAY NIGHT/... 956 PM update... Latest dual pol radar data indicating a layer of melting oriented sw to ne from Bradford County into Delaware County...with a mix in low elevations in ne PA and more sleet or snow in colder high elevations of PA. Precipitation is still all snow to the north of this line. The northern edge of this warm nose is still expected to only push north to around the I-86 corridor tonight before rotating off to the east late tonight. No major changes made to the forecast at this time. Just bumped up snow amounts a touch in ne PA as the mesoscale band potentially extends into parts of Susquehanna, and northern Pike Counties. 400 PM Update A complex winter storm is approaching the area, and will impact us through at least early Monday afternoon. Winter storm warnings are in effect for parts of the area, and winter weather advisories are in effect for the remaining zones. Snow is beginning to develop across parts of the forecast area already, late this afternoon. The light to occasionally moderate snow will continue to overspread the rest of the CWA over the next few hours. As a warmer surge of air aloft moves into NE PA and the southern Catskills by around 10 PM, the snow will mix with sleet, rain and perhaps some pockets of freezing rain over the higher terrain in this area. Further north, from about RTE 17/I-88 north and west, the precip looks to remain snow through the overnight and really the entire event. Binghamton looks to be right on the dividing line between all snow, and some mix, with a little sleet or freezing rain potentially mixing in here late evening until just before midnight. After midnight, colder air aloft associated with the mid/upper level trough begins to spread NW to SE across the forecast area. This will change any rain or mix back over to all around 1 AM for 5 to 6 AM for Tunkhannock-- Scranton--Honesdale--Hazleton and finally by 7-8 AM for Milford and Monticello. Areas that see mixing will limit snowfall accumulations until the changeover time back to snow. This system looks to have a good deal of wrap around, deformation zone snowfall into Monday morning now, as the 700mb circulation moves through the area. The heaviest storm total snowfall should occur right along and just north of where mixing occurs later this evening and tonight; as once again that would be along the I-88 corridor and Rte 17 corridor into Broome county. Snowfall rates up to 1.5 inches per hour are expected. For that reason, confidence has increased enough in higher totals to now include Broome & Chenango counties on the Winter Storm Warning, along with Delaware and Otsego counties. There still remains some uncertainty in exactly where the heavy meso- scale snow band will set up late tonight into Monday morning, but much of the guidance had it in this area, then perhaps sinking south into at least parts of NE PA heading into Monday morning. As this band pivots through Monday morning, and colder air filters in from the NW, this may actually be the timeframe for NE PA and Sullivan county to see the steadiest snow from this event. With higher snow ratios expected across our NW zones, decided to add the rest of our counties into a winter weather advisory, as despite the lower QPF up here, snowfall amount should still be 2-4 inches with localized amounts up to 5 inches...and this snow could impact the Monday morning commute. Otherwise, temperatures overnight will be steady in the upper 20s to lower 30s for Central NY, with 30-35 degrees for NE PA and Sullivan County NY. Winds increase, especially after turning northwesterly behind the front. As for preferred guidance, decided to use a lot of the CAMS, especially the 18z HRRR and RAP for PoPs, then a blend of WPC, 12z ECMWF and some 3km NAM for QPF. The question remains just how long the snow lingers and exactly where into Monday morning or midday. Used a blend of the HRRR, NAM and RAP for thermal profiles and Ptype with this system. Overall snowfall totals in the advisory area should range from 2-6 inches, with 5-8 and perhaps some locally higher numbers in the warning zones. As the coastal low and mid level trough slowly depart the steadier snow tapers to snow showers and flurries from NW to SE Monday morning or early afternoon. High temperatures will be steady on Monday, holding in the upper 20s to mid-30s. Northwest winds increase between 10-20 mph with a few gusts up to 30 mph possible. This combined with the heavy west snow could bring down a few tree limbs, and may cause some isolated power outages...especially in the winter storm warning area. Monday night features much quieter weather, with just a few snow flurries or snow showers possible across the far west and northern zones. Overnight lows dip down into the 20s. Breezy NW winds continue at 10-20 mph, turning westerly later at night. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... 250 PM Update... A shortwave moves into the region from the north Tuesday morning, bringing another round of snow showers to portions of CNY. This system will be accompanied by a weak cold front boundary. Model guidance continues to show some weak instability during the late morning hours as this system moves onshore from Lake Ontario. As it moves further inland, instability quickly weakens in the afternoon. Given this, there is some potential for snow squalls, though moisture is limited throughout most of the DGZ. So more likely, it will be light snow showers with brief quick bursts of heavier snowfall and occasional blowing snow with peak gusts of 25 to 30 kts. The best chances for snow will be along the NYS Thruway corridor but could have some light accumulations as far south as northern portions of the Southern Tier. Temperatures get into the 30s, but with the strong winds present, it will be blustery. Wind chills in the morning will be in the teens. Winds become lighter into the overnight hours as that system will be east of the region. Northwesterly flow could support some lake effect snow showers, though moisture looks to be quite limited. So PoPs were kept fairly low and anything that can develop looks to be fairly light, less than an inch north and along the NYS Thruway corridor. Otherwise, the rest of the region will have dry conditions. Overnight temperatures fall into the teens to mid 20s. While the morning should be fairly quiet, the next system moves in by Wednesday afternoon. A low pressure system moves into the Northeast from the Ohio Valley. The center of the low starts to track north of the region, but then a secondary low develops along the coast. Still, conditions will be cold enough for accumulating snowfall during the second half of the day. A warm front will lift north into the region during the overnight. Along the boundary, a wintry mix will be possible. Once the warm air moves in, this should quickly transition to rain. There is some uncertainty on how far north the warmer air will extend, so snow and wintry mix may remain for portions of CNY. Snowfall accumulations Wednesday will be light, with most receiving 1 to 3 inches during the day. There could also be a glaze of ice, but for now used WPC`s ice accumulation which did not have anything for this area. Given this system is still a few days out, there remains some uncertainties on ptypes and accumulations. Those details will become more clear as this event nears. Winds also pick up late Wednesday as the pressure gradient begins to tighten. Daytime temperatures will be in the upper 20s and 30s. Overnight, temperatures will not have much of a chance to cool down as the surge of warmer air will help slowly warm up temperatures through the overnight hours, possibly getting up into the 40s in some of the lower elevations. && .LONG TERM /THURSDAY THROUGH SUNDAY/... 250 PM Update... The long term will remain active, starting with the aforementioned system. As this system moves out of the region, wrap around precipitation consisting of a wintry mix will mainly affect portions of CNY as a dry slot moves in from the south and brings a break from the precipitation elsewhere. This wintry mix then becomes just snow showers with conditions becoming favorable for lake effect snow following the exit of this system. There is a slight chance that these snow showers continue Friday, though drier air moves in and flow becomes southwesterly as a ridge moves in. This dry period will be brief, at least for CNY, as another system will pass to the north on Saturday. Another round of snow is expected with this system. The weekend could end with yet another round of snow showers as the next system begins to move in. Temperatures this period will generally be in the 30s during the day, though some minor surges in colder air could keep some areas in the 20s on Friday. Lows Thursday night will be in the teens, with teens and 20s then expected for the rest of this period.&& && .AVIATION /03Z MONDAY THROUGH FRIDAY/... Precip has spread over the area, with all terminals seeing snow except AVP, which has rain at the moment. IFR conditions are expected at all NY terminals tonight. A brief lull in snow is expected across ELM/ITH/SYR this evening, and conditions may bounce in and out of IFR for a few hours before settling into IFR for the rest of the night around midnight for ELM and SYR. ITH will see LIFR conditions during the overnight hours. Snow will exit the region by late morning/early afternoon, leaving MVFR ceilings across these terminals through the TAF period. BGM is expected to be in LIFR conditions tonight as heavier bands of snow are expected to set up over the area. Bands should move out of the area around sunrise, with IFR conditions sticking around through late morning and moving to MVFR by the afternoon. AVP is the trickiest forecast as a wintry mix is expected to occur across northeast PA tonight. AVP is expected to see rain through most of the overnight hours with MVFR conditions, changing over to a wintry mix before sunrise and dropping to IFR around 09z through the late morning before becoming MVFR by the afternoon. Outlook... Monday Night and Tuesday...Mainly VFR, except lingering MVFR still possible RME and SYR. Wednesday and Thursday...Storm system will bring wintry precipitation and associated restrictions. Friday...Mainly VFR expected. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...Winter Weather Advisory until 1 PM EST Monday for PAZ038>040- 043-044-047-048-072. NY...Winter Weather Advisory until 10 AM EST Monday for NYZ009- 015>018-022>025-036-037-044. Winter Storm Warning until 1 PM EST Monday for NYZ045-046-056- 057. Winter Weather Advisory until 1 PM EST Monday for NYZ055-062. && $$ SYNOPSIS...MPK/MJM NEAR TERM...BJT/MJM SHORT TERM...BTL LONG TERM...AJG/BTL AVIATION...JTC
National Weather Service Hastings NE
950 PM CST Sun Jan 22 2023 .UPDATE... Issued at 947 PM CST Sun Jan 22 2023 Visibility has dipped to 1/4 mile at a few sites at least briefly this evening. HRRR shows fog continuing to slowly expand and move west to east across the area tonight, so went ahead and put the entire area under a dense fog advisory until 9am. Fog may remain somewhat patchy, but most areas should at least briefly see dense fog at some point through Monday morning. This fog should mix out pretty quickly Monday morning as a surface trough pushes through the area. && .DISCUSSION...(This evening through Sunday) Issued at 206 PM CST Sun Jan 22 2023 Key Messages: * The main message in the short term will be the potential for fog development across the area tonight and into Monday morning. Some of this fog may be dense, with visibility potentially reduced to a quarter mile or less at times. * Temperatures will be cold, but not too far below normal for this time of year, through most of the work week and into the weekend. By the end of the weekend however, temperatures will trend even colder. * Precipitation chances: There is still a very slight chance of a system grazing southeastern-most portions of the forecast area Wednesday, and a slight chance of some snow Saturday night into Sunday, but neither system looks very exciting for our area. Tonight, high pressure will set up over the area and we can appreciate light westerly to northwesterly winds. But with the light winds, high pressure, and pre-existing snow cover fog becomes a concern. Patchy fog is expected to develop this evening across at least northern and western portions of the forecast area, and this will expand in coverage and become more dense moving into the overnight hours and Monday morning. It would not be surprising to see at least a few observations of dense fog (visibility of a quarter mile or less) across the area, especially between around midnight and just after sunrise. Overnight lows will fall to approximately 5 to 10 degrees, coldest over the deepest snowpack. Monday: Fog may persist through at least mid- morning (9-10AM), and it may be dense at times. Fog likely will start to clear a little more quickly across northern and western portions of the area as northwesterly winds increase just enough to scour out the fog with the brief passage of a weak surface front. With this forecast, temperatures were nudged downward a little to account for the snowpack, but highs should still reach the low to mid 30s during the day and drop into the teens overnight. Tuesday: Expect similar conditions to Monday except perhaps the fog. Light northwesterly winds and the snowpack will keep temperatures slightly below normal with highs in the low to mid-30s and lows in the mid- to upper teens. Wednesday-Thursday: A bit of a stronger front will move across the area associated with split upper level low pressure systems, one moving across the Dakotas/Minnesota and the other moving northeast across Oklahoma into Arkansas/Missouri. Precipitation with this second one is the only real chance any of the area has for snow over the next few days, but the majority of the models keep the precipitation to the southeast of the area. Highs will again be in the low to mid 30s both days, with lows in the teens Wednesday night and 20s Thursday night. Friday-Saturday: This is still expected to be the warmest day of the week, with high temperatures reaching the mid-30s to low 40s, so there will likely be a more significant dent put into the existing snowpack by the warmer temperatures. Temperatures Saturday will be a little cooler and struggle to reach as high as freezing. Sunday and beyond: This is where temperatures look to turn even colder as surface high pressure dives out of Canada and the northern Plains into our forecast area. While not currently expecting the level of cold the area received a few weeks ago, temperatures will be noticeably colder than we are currently experiencing. There will likely be breezy winds with this too, so cold wind chill values would not be a surprise. While this is not a certain thing especially 7 days out, there are several long-term models and ensembles indicating at least a few days of much colder than normal temperatures starting around the latter half of the weekend and into the following week. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Tuesday) Issued at 524 PM CST Sun Jan 22 2023 Fog is expected to develop over the area tonight, but timing and coverage is still somewhat uncertain. This should clear quickly Monday morning, but some additional MVFR stratus may return in the afternoon. && .GID WATCHES/WARNINGS/ADVISORIES... NE...Dense Fog Advisory until 9 AM CST Monday for NEZ039>041-046>049- 060>064-072>077-082>087. KS...Dense Fog Advisory until 9 AM CST Monday for KSZ005>007-017>019. && $$ UPDATE...Mangels DISCUSSION...Hickford AVIATION...Mangels
Area Forecast Discussion
National Weather Service Gray ME
1058 PM EST Sun Jan 22 2023 .SYNOPSIS... Low pressure will track across the Gulf of Maine tonight through Monday, bringing widespread accumulating snowfall to the region. This system will then depart the area late Monday, leaving behind gusty winds and scattered snow showers on Tuesday. High pressure will briefly build across New England on Wednesday, which will then be quickly followed by another storm system Wednesday night and into Thursday. This system has the potential to bring significant amounts of both rain and snow to the region along with gusty winds. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 1050pm Update...With front end snow overperforming amid good snow ratios, Winter Storm Warnings have been expanded into southern Oxford, Cumberland highlands, and northern Carroll county. Also added wording to current warnings regarding some potential banding Monday afternoon that could impact the afternoon commute for a good portion of the Warning area outside of the mountains. Temps continue to run on the cooler side of the forecast, and have continued these trends overnight. North winds continue at the surface, but a melting layer has made progress into far SE NH. This has swapped Portsmouth to rain and is expected to continue north towards Manchester. 8pm Update...Snow has begun across NH and now moving into SW ME. Obs were running a couple degrees cooler than fcst, so adjusted these down and blended some of the HRRR in for the next few hours. Good WAA throughout should prove to moderate temps somewhat, especially across southern NH. KBOX CC displays a vivid band of transitioning precipitation moving north. The last few scans have stalled somewhat short of the NH border, and think S NH will remain snow for a couple more hours. mPING reports within this band range from snow on the north side to ice pellets and freezing rain/rain to the south. Will watch how this progresses, but current forecast seems well off for timing when mix may begin to invade SE NH. Previous Discussion... Primary changes to the going forecast for the incoming winter storm has involved a slight shift north in the track of the low pressure system as well as a more amplified system. This has led to a modest increase in QPF with snow amounts increasing along the interior and decreasing slightly in the lower Merrimack Valley to NH Seacoast due to mixing. However, these changes to snowfall amounts have not resulted in any changes to the going Winter Storm Warning or Advisory Headlines. Another important development in the 12Z guidance is that with a more amplified system there is a signal for moderate to heavy snow bands to pivot over the coastal plain around mid day into the afternoon. This banding signal during the afternoon may very well be when areas across SE New Hampshire and coastal SW Maine will see the best accumulating snow. So current thinking is that impacts to the evening commute will be likely, especially along the I-95 corridor. Forecast Details: Broad area of low pressure is presently over central Appalachia down to the Gulf Coast and will emerge off the Mid Atlantic coast tonight and then track towards the tip of Cape Cod Monday morning. This low will then slow its northeast progression as it enters into the Gulf of Maine late Monday morning leading to greater banding potential tomorrow afternoon across much of the area south of the mountains. Low pressure deepens Monday afternoon and evening as it tracks over Nova Scotia with the final snow ending along the coast Monday evening followed by gusty NW winds into Monday night. Precipitation will break out from SW to NE starting in SW NH around 7 PM. Initially snow will be the dominant precipitation type across southern NH for a few hours late this evening with snow then mixing with sleet and rain mainly across SE NH into coastal SW Maine. This is making for tricky forecast here for snowfall amounts leading into the morning commute. Parts of the area from the lower Merrimack Valley to coastal SW Maine may see limited accumulations or see initial accumulations washed away from a change to rain. Further inland, where precipitation is expected to remain all snow, snowfall rates will climb into the 0.5 to 0.75 inch per hour tonight with some indications that snowfall rates will approach 1 inch per hour for few hours leading into the morning commute. Current forecast brings 3-5 inches of snow across much of the area before the morning commute gets underway, with the exception being for less accumulations where precipitation mixes with and possibly changes over to rain. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... The snow/mix/rain line will push towards the coast Monday morning with snow expected to be the dominant p-type from mid morning into the evening. Snowfall rates may drop of some mid to late morning before increasing again with the development of moderate to heavy snow bands. As the low pulls east during the afternoon NW winds will ramp up with peak gusts topping out around 35 mph. Total snow accumulations are within the 5 to 10 inch range with lower amounts near the immediate coast and across the far north. Snow tapers off from NW to SE with snow ending along the coast by late tomorrow evening. Gusty NW winds continue into Monday night and with some areas seeing heavy wet snow these winds could lead to further power outage issues. Highs on Monday will be in the upper 20s north to low 30s south. Many areas south of the mountains will be near the freezing mark with leading to wet surfaces that could refreeze Monday night if left untreated as temperatures drop into the upper teens to low 20s. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Overview: A shortwave will swing across northern New England on Tuesday, likely resulting in scattered snow showers across mainly the north and mountains. Canadian high pressure will then build across the area on Wednesday, bringing a brief reprieve from the active weather pattern. This will then be followed by potentially another significant storm system Wednesday night through at least the first half of Thursday as an approaching deep trough axis moves east with a coastal low developing ahead of it. Impacts: Snow showers on Tuesday may become locally heavy in nature with a non-zero threat for an isolated snow squall, especially across the north and mountains. This may result in brief localized visibility restrictions along with rapidly deteriorating road conditions. Quiet weather on Wednesday will then be followed by another storm system Wednesday night through part of Thursday, which could bring multiple hazards ranging from heavy wet snow accumulation, rain, and gusty winds. Forecast Details: Brief mid-level ridging on Tuesday morning will be pushed to our east during the afternoon as a shortwave trough quickly moves across northern New England. This will bring the potential for scattered snow showers, especially across the north and mountains during the afternoon. Steepening low to mid-level lase rates will also introduce a threat for an isolated heavier snow shower or snow squall. The latest NAM snow squall parameter does show increased values coinciding with QPF across the north and mountains and therefore this will need to be watched for potential localized brief visibility restrictions and deteriorating road conditions. Further to the south, downsloping winds should keep most areas dry with highs into the upper 30s to lower 40s. Clearing skies south of the mountains can be expected Tuesday night with a lingering stratocumulus deck across the north as lows fall into the single digits to teens thanks to CAA. Canadian high pressure will then build across New England on Wednesday, allowing for a brief reprieve from the active weather pattern. High temperatures will be seasonably cool into the upper teens across the north and mountains to the lower and middle 30s further to the south. During the day on Wednesday a deep trough axis will be moving through the center of the country with a surface cyclone centered around the Tennessee River Valley. This system will ultimately become our next potentially significant weather system to impact the area Wednesday night through at least the first half of Thursday. Current indications are that the surface low near the Tennessee River Valley will move northward to the eastern Great Lakes region on Wednesday night as the 500 mb trough moves east towards the eastern Seaboard while spawning a coastal low somewhere in the Northeast. There remains significant uncertainty in the timing of this complex storm system as well as the placement of both the surface and upper level low, which will have large impacts on precipitation types and amounts. The phasing of these two systems will also be important in determining temperature profiles but for now would expect a front end thump of accumulating snowfall Wednesday night into early Thursday within the WAA regime before the system potentially drags in enough warm air for a mix or changeover to rain, especially south of the mountains. Regardless, this system will need to be closely watched as significant amounts of precipitation in the form of snow and/or rain are possible along with gusty winds. Behind this system mainly dry weather looks likely through at least the end of the week with generally near to below normal temperatures. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... Short Term...IFR/LIFR as snow moves into the region. Some mixing is possible at KMHT, KPSM, KPWM, and KRKD, although freezing rain is not expected. SN continues across all terminals through Monday for continued IFR to LIFR conditions with conditions improving Monday night. Long Term...Mainly VFR conditions will prevail Tuesday through the daytime of Wednesday. The exception will be within any SHSN on Tuesday afternoon, which may bring brief periods of restrictions. The greatest confidence for this to occur is at KHIE. Our next storm system then arrives Wednesday night through at least the first half of Thursday, bringing widespread precipitation and low CIGS along with potentially gusty winds. Conditions will then improve Thursday night through Friday. && .MARINE... Short Term...Low pressure tracks across Cape Cod tonight into the Gulf of Maine. Winds turn northeast late tonight and then northerly to northwesterly Monday afternoon as the low exits towards Nova Scotia. NE winds climb above 25 kts late tonight and when winds shift northerly to northwesterly Monday is when gusts will reach Gale Force. Gales continue into Monday night as the low deepens to the east of the waters. Long Term...SCA to low end gales are likely on Tuesday with west-northwesterly wind gusts up to 30-35 kts possible and seas of 6-8 ft. High pressure then briefly builds in on Wednesday, bringing lighter winds and seas before another storm system arrives on Thursday, bringing another period of potential gale force winds and widespread rain. && .TIDES/COASTAL FLOODING... Minor coastal flooding and potential splash-over is expected around the time of high tide late Monday morning as low pressure tracking across the Gulf of Maine coincides with high astronomical tides. Coastal Flood Advisories have been issued for Coastal Cumberland, Coastal York, and Coastal Rockingham counties. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Winter Weather Advisory until 7 PM EST Monday for MEZ007-008- 013-014. Winter Storm Warning until 7 PM EST Monday for MEZ012-033. Winter Storm Warning until 10 PM EST Monday for MEZ018>028. Coastal Flood Advisory from 10 AM to 2 PM EST Monday for MEZ023-024. NH...Winter Weather Advisory until 7 PM EST Monday for NHZ001>003. Winter Storm Warning until 7 PM EST Monday for NHZ004. Winter Storm Warning until 10 PM EST Monday for NHZ005>013-015. Coastal Flood Advisory from 10 AM to 2 PM EST Monday for NHZ014. Winter Weather Advisory until 10 PM EST Monday for NHZ014. MARINE...Gale Warning from 7 AM Monday to 6 AM EST Tuesday for ANZ150>154. && $$ SYNOPSIS...Tubbs NEAR TERM...Cornwell/Schroeter SHORT TERM...Schroeter LONG TERM...Tubbs
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
543 PM CST Sun Jan 22 2023 .SHORT TERM... Issued at 300 PM CST Sun Jan 22 2023 Through Monday night... Light snow continues in the area this afternoon, but will slowly begin to taper off as we head into this evening as the sheared-out wave responsible for generating this precipitation continues to progress eastward. Not really expecting much of any additional accumulations given the above freezing/marginally below freezing surface temperatures, relatively poor snow quality, and pedestrian snow rates. The lone exception to this could be portions of northwest Indiana (especially Porter County in our CWA), where marginally favorable lake effect parameters and a modest degree of convergence over Lake Michigan could support lake effect snow featuring steadier snow rates for a few hour long period this evening. However, even if this materializes, surface temperatures will be hovering around freezing there, so don`t think that this would result in anything more a coating of snow on grassy and elevated surfaces. Otherwise, flurries may linger around a little while longer in other parts of our forecast area this evening, while our ever-present stratus deck limits temperature falloff tonight to whatever cold air advection off of roughly 5-10 mph north to northwesterly winds can muster. On Monday, the center of a surface high pressure dome currently over the central/southern Plains will slide eastward into the southern Mississippi River Valley. Meanwhile, a sheared mid/upper-level shortwave and an associated surface low pressure system will translate eastward across northern Ontario and James Bay during the daytime with a frontal trough swinging over the northern Great Lakes. Precipitation associated with this trough should remain north of our forecast area, but the somewhat compressed pressure gradient between the trough and high pressure to our south will yield a rather breezy afternoon, when southwesterly winds are likely to gust to around 30 mph. Perhaps of more interest, though, is whether we will break out of our mid-January malaise and see the Sun for basically the first time in a week tomorrow. Most forecast guidance has been advertising for a while now that Monday would be the day when the incessant stratus would finally relinquish its grasp over the region. Some newer guidance that has come in today still seems to think that this will be the case, but other guidance, particularly the HRRR and RAP, is not quite as bullish. The HRRR and RAP, for the most part, have done a fairly decent job handling these seemingly eternal stretches of stratus that we`ve seen this month, so it would seem unwise to bet against these models, even when considering that the usually moist- biased NAM and 3km NAM erode the stratus quicker than you think they would (though the 18Z runs of these models did trend towards holding the stratus around longer here than prior runs). When considering that the stratus deck remains sprawled all the way back into portions of western Iowa and Minnesota at this hour, that there will be little to no dry air advection prior to Tuesday, and that there`s even some hints of ascent resulting from warm air advection aloft, the HRRR and RAP solutions appear to be more likely to verify than the other more optimistic guidance. Throw in the facts that this time of year is climatologically favorable for stratus to linger around seemingly whenever it has the option to and that this has already been the case the past several days, and there`s plenty of reason to be pessimistic that we`ll see the Sun tomorrow. Thus, it felt prudent to raise the amount of sky cover advertised in our forecast grids substantially throughout the day on Monday. Certainly can`t completely rule at least some cloud breaks materializing and allowing some lucky locations to at least catch a glimpse of the Sun at some point tomorrow afternoon, but am thinking that anything beyond that is looking increasingly likely to be a pipe dream. Ogorek && .LONG TERM... Issued at 300 PM CST Sun Jan 22 2023 Tuesday through Sunday... No big changes in forecast reasoning or guidance with the 12z suite of model runs. Primary highlights of the long term portion of the forecast include: * Accumulating snow likely to overspread the area from south to north overnight Tuesday into Wednesday morning. * Should be north-south gradient in snowfall accumulations across the CWA, with current data favoring higher accumulations south. * Intermittent snow showers likely to persist through the end of the week with threat for swaths of light accums and hazardous travel conditions. Water vapor imagery early this afternoon shows a well defined southward moving upper low over the Intermountain West that will be our weather maker mid-week. Secondary player in our mid-week weather is a strong Pacific storm system over the Gulf of Alaska that is progged to ride the polar jet stream across western Canada before digging south into the northern Plains later this week. The 12z operational runs and their respective ensembles really didn`t depict any changes that graduate from the noise level to something that is noteworthy with the mid-week system. The 12z operational runs of the GFS and ECMWF are actually in remarkably good agreement with each other through 12z Wednesday. Later Wednesday into Wednesday night, the operational GFS does bend the surface low track back a bit farther west than most of its ensemble members and the ECMWF and EPS. As far as sensible weather conditions go, really no meaningful differences between these models, both have the swath of heavier snow just to the south and east of our CWA. However, both also have a broader area of lighter snow blanketing most of our CWA farther to the north and west of the band of heavier snow than is typical with most of these mid-latitude cyclones. This is likely a result of constructive interaction with the aforementioned northern stream shortwave trough digging south just to the northwest of the southern stream cyclone to our southeast. Current model QPF for late Tuesday night into Wednesday combined with the somewhat marginal thermal profiles, looks to favor a 1-3 or 2-4 inch type snow along and north of I-80. Farther south, particularly across northwest Indiana, if current runs were to verify, accums would get solidly into advisory level criteria. Some guidance is showing some enhanced QPF over northeast IL associated with some lake enhancement, particularly Wednesday afternoon and evening. Guidance is in good agreement that air temps will probably be a hair above freezing by then, and if today is any indication, snow may struggle to accumulate much during the afternoon. In addition, lake effect parameters appear quite marginal for lake enhancement with shallow tops to the lake induced convective layer and weak instability owing to the lack of any strong push of cold air. This makes me somewhat skeptical of the models showing significant enhancement to the QPF as a result of the lake. Finally, while there is (and has been for a couple runs) pretty solid model and ensemble agreement in the handling of this system, it is still quite plausible that guidance could change. While guidance never really truly phased that northern stream shortwave with the cut off low over the southwest, there certainly seems to be some interaction with the northern stream wave perhaps pulling the southern stream wave a bit farther north, and this certainly seems to be resulting in a broader snow area on the NW side of this cyclone. Models are notorious for struggling both with the movement and timing of cut off lows (like the one digging into the southwest) and also can struggle at times handling the interaction of northern and southern stream waves, like is progged mid-week. All of this to say, that current strong model agreement doesn`t necessarily equate with high confidence in the forecast. If the timing or amplitude of either wave changes much, then the degree of interaction could change. Less interaction could result in a sharper cut off to the snow on the northwest flank of the system, or a track farther south could lessen our snow amounts. Conversely, more interaction/phasing and the heavier snow with the TROWAL could result in higher impact accumulations farther north into our CWA. Beyond this southern stream wave`s snow, maintained/nudged up pops Wednesday night into Thursday associated with the northern stream shortwave. Combination of forcing with this trough and instability resulting from the very cold air aloft (-33C at 500mb), should result in a pretty favorable set up for at least scattered snow showers. Some indication that we could see a brief break in the snow shower chances (at least in these latest runs) Thursday night, before the next northern stream trough moves across the region Friday. Guidance remains rather inconsistent with the handling of the individual waves, and to an extent, with the overall pattern by Friday into next weekend. Given the lower confidence, made no changes to NBM, which does have snow shower chances with the shortwave Friday then potentially another more impressive system later in the weekend or early next week. - Izzi && .AVIATION... For the 00Z TAFs... Main aviation weather concerns: * MVFR stratus lowering to IFR late evening into early overnight and persisting through at least Monday morning; LIFR possible namely at RFD * Depending on thickness of clouds, southwesterly wind gusts might exceed 25 kt Monday late day and evening * Non-zero chance of brief light freezing drizzle or light snow Monday evening The weather disturbance that brought us today`s light snow is exiting the area with only brief, scattered VFR flurries remaining until 02Z-04Z. Cloud bases are MVFR over the Chicago metro early this evening, but widespread IFR exists upstream over Wisconsin and Minnesota. Confidence is high in this IFR returning, although lower confidence on timing, particularly how long it will persist on Monday. The strength of the inversion forecast above the stratus indicates it may persist all day Monday, yet at the same time the forecast cloud depth is fairly shallow (<1,200 ft thick), at least relative to recent IFR events. So confidence is low in cloud base height Monday afternoon into evening. Winds early this evening are mainly from the north-northwest, with the exception being temporary north-northeast winds near Lake Michigan (including MDW) through 01-02Z. The winds will back more westerly by daybreak and then southwesterly Monday afternoon. With the forecast of low clouds, have leaned toward gusts not increasing quickly. By Monday evening though, with 30 kt flow forecast near 1 kft, gust frequency above 20 kt is likely to increase even if low clouds are present. For Monday evening, there is a cold front approaching northern Illinois. Lift ahead of this may be enough, especially if low clouds are present, for spotty flurries/light freezing drizzle. Confidence is too low at this time for including in the forecast. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...Small Craft Advisory...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744- LMZ745...2 PM Monday to 3 AM Tuesday. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Tulsa OK
916 PM CST Sun Jan 22 2023 ...New SHORT TERM... .SHORT TERM... (The rest of tonight) Issued at 916 PM CST Sun Jan 22 2023 Upper level trof axis continued to push off to the east this evening...which had allowed for the scattered areas of light rain mixing with snow/sleet this afternoon to exit Northwest Arkansas as well. In response to the departing cover was also moving off to the east and southeast...with mostly clear skies common across much of Eastern Oklahoma. Temps at mid evening were in the mid 20s to lower 30s in the clear skies...while mid 30s to low 40s remained underneath the clouds. Overnight cover should become mostly clear over the majority of the CWA. There are some indications of possible low clouds trying to hold on in far Northwest Arkansas...and as such will keep a mention of partly cloudy late tonight. Also overnight...scattered high clouds...associated with the much anticipated Tuesday low pressure system...could spread into parts of Northeast Oklahoma. In any case...light winds with mostly clear to partly cloudy skies should help low temps to fall into the 20s across the CWA. The normal cold locations near the Kansas border may have a chance to reach upper teens before the high clouds spread in. Current forecast configuration seems to have a good handle on the mentioned above. Thus...for the evening update...have only added a few adjustments to sky grids based on latest Satellite trends...and a few tweaks to hourly temp/dewpoint grids to account for latest obs. && .LONG TERM... (Monday through Sunday) Issued at 211 PM CST Sun Jan 22 2023 Monday is expected to be a transition day with high pressure in control at the surface and aloft with temperatures near normal for this time of year. The potential for winter weather impacts will ramp up Tuesday into Tuesday night. Impactful snow amounts are looking more likely across portions of northwest Arkansas and the higher terrain areas of southeast Oklahoma Tuesday afternoon into Tuesday night. A Winter Storm Watch will be issued for most of our Arkansas Counties with this forecast package. This area has the highest likelihood of seeing 4 to 8 inches of snow. Additional Counties may be added to the Watch with time. A mid-level low currently over the Intermountain west will be a main player in this winter weather event for eastern Oklahoma and western Arkansas. This feature will sag into northern Mexico as we move into Monday night and then sweep across the Southern Plains Tuesday and into the Mississippi Valley by Wednesday morning. The associated surface low will gather steam along the Texas Coast Tuesday morning before moving across northern Louisiana and northern Mississippi Tuesday night. The current forecasted track of this system would put portions of northwest Arkansas in the most favorable zone for heavy snow. This is especially true given the quality of moisture that this system with have available (P.W values 1/2-1 inch). However, the limiting factor will be the near surface temperatures. Temperatures are expected to fall to near the freezing mark as the precipitation begins Tuesday morning/early Tuesday afternoon and remain close to freezing through Tuesday night. This will allow the rain to gradually to mix over the snow late Tuesday afternoon into the evening hours across most of the area. Again, the heaviest amounts are forecast across northwest Arkansas and higher terrain of areas of southeast Oklahoma. Lesser amounts are expected across the remainder of the area. The precipitation is expected to exit the region Wednesday morning as the storm system departs the area. This forecast will continue to be refined with time with additional winter weather headlines likely. Quiet weather is expected Thursday into Saturday with temperatures rising above normal as we move into the weekend. The next chances of rain are expected Saturday night into Sunday as the next cold front moves through the area. Temperatures look to be trending much colder as we move into the following week. && .AVIATION... (00Z TAFS) Issued at 456 PM CST Sun Jan 22 2023 VFR cigs across E OK should scatter out this evening, with VFR conditions expected thru the end of the period with light winds. Will need to watch KBVO for the possibility of a deck of IFR cigs possibly bleeding down from KS toward morning. For the NW AR sites, MVFR cigs likely to scatter out this evening as well, but chances are higher here for the aforementioned deck of IFR cigs forecast in the HRRR to bleed down into this area toward 12Z. Low clouds should scatter out everywhere by 18Z Monday. Lacy && .PRELIMINARY POINT TEMPS/POPS... TUL 24 49 29 40 / 0 0 0 70 FSM 29 50 30 39 / 0 0 0 90 MLC 26 52 31 38 / 0 0 0 90 BVO 19 48 25 42 / 0 0 0 50 FYV 26 49 28 40 / 0 0 0 80 BYV 27 47 28 40 / 0 0 0 60 MKO 26 48 30 40 / 0 0 0 80 MIO 24 46 28 42 / 0 0 0 50 F10 26 50 30 37 / 0 0 0 90 HHW 27 52 33 39 / 0 0 0 100 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...Winter Storm Watch from Tuesday afternoon through late Tuesday night for ARZ001-002-010-011-019-020. && $$ SHORT TERM...20 LONG TERM....10 AVIATION...30