Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/22/19

National Weather Service Albany NY
912 PM EST Thu Nov 21 2019 .SYNOPSIS... High pressure will move east of the region tonight. A warm front will bring a light rain and snow shower mix overnight with a fast moving low pressure system. The cold front will move through tomorrow with isolated to scattered rain to snow showers and blustery conditions. High pressure will bring fair and cold conditions to open the weekend before a complex storm system brings potentially a wintry mix of precipitation types Saturday night into Sunday. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Clouds thickening and lowering and just some spotty sprinkles in central and eastern NY as 00Z soundings show quite dry at low layers. Temperatures are around freezing in parts of the southern Adirondacks, Lake George area and southern VT. So, sprinkles could start as some freezing sprinkles before south winds begin and temperatures warm. Just minor adjustments to sky cover, temperatures and and adding slight chances for light freezing rain in areas where temperatures are around freezing. Previous AFD has a few more details and is below... High pressure at the sfc and aloft will slowly move east of the region tonight. The mid and upper level ridge axis moves off the New England Coast after 06Z/FRI. Mid and upper level heights fall, as a warm front lifts north and east across the region. The weak warm advection or isentropic lift on the 290K surfaces will allow for some light snow showers to impact the western Mohawk Valley north and east into the southern Adirondacks. The best synoptic forcing moves into the North County. A few ice pellets may mix in but we are expecting a brief spell of snow transitioning to light rain showers, as temps will fall off quickly prior to midnight, but then rise after midnight or steady. The 3-km HRRR and NAMnest support a quick snow to rain transition. Lows should be early in the mid to upper 30s in the lower elevations and lower to mid 30s over the higher terrain. The winds will increase out of the south to southwest. Any snow accumulations especially over the higher terrain of the Adirondacks will be in the coating to less than a half an inch range. c&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... Tomorrow...A trough of low pressure lifts poleward across south-central Quebec. A rather strong cold front will sweep across the region in the late morning through the early/mid pm. Temps should rise to normal to above normal levels. However, temps may fall quickly in the wake of the front. Strong low- level cold advection will occur and the latest BUFKIT momentum transfer profiles do show the possibility of mixing 35 kts or so from 2-2.5 kft AGL. If we mix a little higher a few 40 kt gusts are possible, but this should be briefly and mainly with the frontal passage, and an SPS may be able to handle it. The stronger winds should be from the Mohawk Valley, Capital Region, Berkshires northward. The H850 winds will increase to 35-45 kts or so by the early to mid pm. A few heavier snow showers or an isolated squall is possible over the western Adirondacks where better low-level moisture and vorticity advection is in place with steepening low and mid- level lapse rates. Most the region will see isolated to scattered rain to rain/snow showers with the frontal passage. It will become blustery and cold. The better convergence with the boundary is from the I-90 corridor north. Highs will be in the mid 40s to a few spotty 50F readings in the mid Hudson Valley and NW CT, except across the southern Adirondacks and southern Greens where upper 30s to lower 40s are possible. Temps will fall into the 30s west of the Hudson River Valley. It will be blustery with west to northwest of 15 to 25 mph. Some scattered light dustings to a few tenths of an inch of snow are possible especially over the Adirondacks. Friday night...A brief connection with lake effect snow showers and flurries may impact the northern Catskills, and western Mohawk Valley early in the evening. Otherwise, clearing skies and diminishing winds will occur, as high pressure builds in from the OH Valley with cold and dry conditions with lows in the 20s with a teens over the southern Adirondacks and southern Greens. Saturday...The weekend opens with fair and cold weather with high pressure over the upper Mid Atlantic States and Northeast. Max temps will be below normal by at least 5 degrees. Sunshine will give way to increasing mid and high clouds late. Highs will be in the upper 30s to lower 40s in the lower elevations, and upper 20s to mid 30s over the hills and mtns. Saturday night...A southern stream system lifts northeast towards the forecast area from the Mid Atlantic States. The region will see clouds thicken and lower with low-level isentropic lift increasing from the southern stream system, and a northern stream short-wave will be approaching from the Great Lakes Region. The CMC/EC/GFS/Ensembles show an increase of thermal advection for initially some snow perhaps transitioning to sleet/freezing rain well after midnight south of the Capital Region. Some light accumulations are possible. This forecast may change based on the thermal profiles, track and evolution of the system. The 12Z NAM keeps this system unphased with little impact. Overall, some snow to start perhaps transitioning to a wintry mix. We will keep mention in the HWO. Lows will be in the 20s to lower 30s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... At the start of the long term period, low pressure will be quickly strengthening off the mid Atlantic coast as it lifts northeast to the south of New England. Meanwhile, the primary low pressure area over western New York will be weakening, as the offshore storm takes over. With our area on the northwest side of the storm, there looks to a steady shield of precip that occurs through much of the day. Precip type will likely be tied to elevation and precip intensity. 12z GFS BUFKIT soundings show temps warming up just enough in the boundary layer for the Capital Region and other valley areas to the south and east for precip to be mainly rain through the day as surface temps warm into the mid to upper 30s. However, the profile may be more isothermal near 0 C across the higher terrain, as well as areas north/west of the Capital Region, which could allow for wet snow (perhaps some pockets of sleet) for those areas. Will allow for some light snow accumulation on Sunday for areas outside the immediate Capital Region, mid Hudson Valley, and NW CT, but will keep amounts of generally just a coating to a few inches, as GEFS suggest QPF amounts will only be a few tenths of an inch. Most areas should be done seeing precip by late afternoon or early evening, with precip exiting western New England last. Most areas look dry for Sunday night, although some lake enhanced flurries or light snow showers are possible for the western Adirondacks, with temps falling into the 20s across most of the area. Behind this departing storm, brief shortwave ridging and surface high pressure will pass across the area for Monday into Tuesday. This should allow for dry conditions with a partly to mostly clear sky. Highs on Monday will be in the lower to mid 40s for valley areas, with highs a little milder on Tuesday, generally in the mid to upper 40s. Warm advection will be underway for Tuesday night, so temps may not fall off too much with clouds increasing. A few showers are possible across the Adirondacks by late in the night, otherwise, it looks dry with temps generally remaining above freezing. Strong low pressure will be passing across the Great Lakes and into southern Canada on Wednesday. The storm`s cold front should be moving through area for Wednesday with a band of rain showers. Temps look to warm up plenty ahead of the front, both at the surface and aloft, so any precip should be just plain rain. Highs should be well into the 40s for most locations. Behind the front, temps will cool off and some lingering wrap around showery precip will occur for Wednesday night into Thursday (Thanksgiving Day) as the upper level trough cuts off and slowly moves across the area. Precip looks mainly rain showers for valley areas due to surface temps in the mid 30s to low 40s, but high terrain areas could be seeing some snow shower activity with temps in the low 30s. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Localized fog over GFL will mix out as higher clouds thicken and showers move into the region. Then VFR conditions will prevail at the TAF sites this evening. Clouds with ceilings at or above 5000 feet will increase ahead of a warm front this evening, then scattered light showers will develop overnight at GFL/ALB/PSF. A little freezing rain is possible with these showers at GFL as temperatures will be near freezing. Ceilings and visibilities may briefly lower to MVFR in showers after midnight tonight and until around 14Z-15Z. VFR conditions will prevail on Friday as a cold front moves east of the area. Gusty westerly winds will develop along and behind the front with speeds increasing to 15 to 25 kts along with a few higher gusts into the afternoon. Outlook... Friday Night: Low Operational Impact. Breezy NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: Moderate Operational Impact. Likely RA...SN. Sunday: High Operational Impact. Likely RA. Sunday Night: Low Operational Impact. Slight Chance of SHRA...SHSN. Monday to Tuesday: No Operational Impact. NO SIG WX. && .FIRE WEATHER... The Fire Weather Season ends today. The issuance of this product will resume in Spring 2020. && .HYDROLOGY... No widespread problems are expected on the main stem rivers and within the ALY HSA the next several days into the middle of next week. The precipitation from the system tonight into tomorrow will have little effect on the ALY HSA waterways. A complex storm system may bring some rain, snow and or a wintry mix Saturday night into Sunday with light to moderate amounts of QPF, but their is still uncertainty in the track, evolution and the amount of QPF with this system. The bottom line, there will be minimal rises on the waterways. For details on specific area rivers and lakes, including latest observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Wasula NEAR TERM...NAS/Wasula SHORT TERM...Wasula LONG TERM...Frugis AVIATION...NAS FIRE WEATHER...Thompson/Wasula HYDROLOGY...Wasula
Area Forecast Discussion
National Weather Service Denver/Boulder CO
838 PM MST Thu Nov 21 2019 .UPDATE... Issued at 801 PM MST Thu Nov 21 2019 Latest HRRR develops the potential for enhanced snowfall bands overnight along the I-25 corridor, from around I-70 south to Monument. For this reason, have increased the expected snowfall amounts overnight into Friday morning. Safe bet is for 1-4 inches, with higher amounts 5-6 inches IF the localized bands develop. Expect snowfall to increase over the Palmer Divide by midnight, then migrate northward into the Denver area in the 2 to 6 am period. If this occurs, then snowpacked and/or icy roads could likely impact the morning commute, especially along the I-25 corridor between Denver and Monument. No highlights at this time with plenty of uncertainty regarding this outcome. Will have to wait and see how things transpire on radar over the next 2 to 4 hours and update if needed. && .SHORT TERM...(This evening through Friday) Issued at 457 PM MST Thu Nov 21 2019 Water vapor satellite imagery showing a closed low near Las Vegas with diffluent flow aloft over Colorado. This is expected to bring areas of light snow this afternoon. Once the diffluent flow aloft ends, expect the snow to taper off. A short wave trough over northwest New Mexico will track east-northeast and form a new upper level low over southeast Colorado late tonight. This is expected to bring additional snow tonight and into Friday morning. Overall dynamics are weak, so snowfall amounts across the lower elevations are expected to be light, 2 inches or less. The mountains should see more snow 2-6 inches through Friday morning. Snow may linger into Friday afternoon in parts of the mountains where northwest ridgetop winds produce orographic lift and light snow. Additional snowfall Friday afternoon will be very light. Roads may become slippery after sunset this evening as temperatures decrease and road temperatures falls. Best chance for slick roads will be through the mountain passes. Because of the overcast skies, temperatures will be slow to cool tonight. Expecting lows in the lower to mid 20s across most of the area. Clouds will persist through the morning and then slowly clear Friday afternoon. Highs will be chilly with readings in the 30s over northeast Colorado. .LONG TERM...(Friday night through Thursday) Issued at 457 PM MST Thu Nov 21 2019 It will be warmer on Saturday and Sunday. Northwest winds aloft will increase behind a weak shortwave and should create some mountain wave amplification Sunday and Sunday night. There could be a small high wind threat for the Front Range, more likely it will be windy over the ridges and east slopes, spilling out onto the plains ridges but not as much elsewhere. There`s decent model agreement on a strong jet streak/shortwave trough/cold front for Monday into Tuesday. The main feature appears to be the forcing associated with the jet streak, probably Monday night. Models are generating decent precipitation with this, somewhere between .25 and .75 inch, reflecting likely decent forcing in a fairly favorable environment. So this could be a short-lived but significant event. Still some question about timing and placement of the snow band. After that, it`s warmer again with a shortwave ridge on Wednesday and then southwest flow aloft. There`s less agreement with trough position and shortwaves toward the end of the week, with a strong preference though for an upstream mean trough and weaker shortwaves in strong southwest flow aloft over Colorado. This would lead to a warmer pattern with a good chance of light orographic/warm advection snow over our mountain areas. Snow chances for the plains should not be very good at first in this pattern. The model blends had some low PoPs for the plains Thursday, but other than spillover into the foothills this looks like too much. There may be a better chance of a good shortwave or the trough edging further east for Friday or next weekend. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 801 PM MST Thu Nov 21 2019 Latest HRRR runs develops an a enhanced area of snowfall over the Palmer Divide 06-07z then move northward into the Denver area from 09z-13z. Light snowfall will increase by midnight with the potential for brief period of moderate/heavy snowfall. Expect snowfall will range from 1-3 inches but can`t rule out higher of 4-5 inches if one of these heavier bands impacts the terminals for a couple of hours. Low clouds will continue through tonight and into Friday morning. Ceilings could fall below 500 feet late tonight as the snow develops. The snow should diminish by 15z Friday morning. Ceilings start to climb after 16Z Friday and the low clouds eventually scatter out around 20Z Friday. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Cooper SHORT TERM...Meier LONG TERM...Gimmestad AVIATION...Cooper
Area Forecast Discussion
National Weather Service Burlington VT
846 PM EST Thu Nov 21 2019 .SYNOPSIS... Changeable weather is expected over the next two day across the North Country. An upper level trough of low pressure and its associated cold front will bring some rain and snow showers to the region tonight along with the potential for some very light freezing rain east of the Green Mountains. As the cold front moves across the area on Friday expect gusty winds southwest to west winds. In addition...rain showers will be changing over to snow showers late in the day Friday before coming to an end Friday evening. High pressure builds in for late Friday night and Saturday bringing drier weather to the area along with slightly below normal temperatures.pitation to the region on Sunday, in the form of rain and wet snow. && .NEAR TERM /THROUGH FRIDAY NIGHT/... As of 846 PM EST Thursday...Modest updates to tonight`s forecast, mainly to increase probabilities of light freezing rain and associated light icing potential in sheltered valleys of the eastern Adirondacks and the eastern half of Vermont. Latest observational data show much of this area has dropped to near or below freezing this evening as temperatures have fallen in advance of thicker cloud cover and warm advection-driven light pcpn advancing east from the eastern Great Lakes. Thermal profiles from latest model guidance and recent ACARS data from Pierre-Trudeau Intl in Montreal show a pronounced warm layer developing in the mid levels as strengthening southwesterly flow in the 925-850 mb layer advects into the forecast area. As such, any precipitation that does fall in these areas should occur as light freezing rain, at least for a few hours. Based off latest guidance and obserations out to our west overall QPF should remain light and generally less than a tenth of an inch through sunrise Friday. That said, some light icing concerns on the order of a few hundredths will certainly be possible in these areas and have issued Special Weather Statement to cover this potential. Areas in the Champlain and St. Lawrence Valleys should largely stay warm enought to preclude any light icing threat. PoPs were derived from a blend of latest HRRR and HRRR-X data with hourly temperatures trends through 12 UTC Friday a blend of most recent LAMP and bias-corrected LAMP output which has the best handle on the current situation. Have a great evening. Prior discussion... Expect quite a few changes with the weather over the next 36 hours. Increasing clouds tonight and warm air advection will limit the amount of cooling over the area tonight...with lows likely being in the evening hours and then slowly rising overnight. This should help to limit the freezing rain potential as low level temperatures to support freezing rain will only exist for a very short time east of the Green Mountains in Vermont. Plus the amount of precipitation expected overnight where the thermal profile supports freezing rain will be limited. As a result...can see a trace to maybe 0.01 inches over parts of north central and northeast Vermont. Meanwhile the remainder of the area would experience rain or snow showers with any snow accumulations less than an inch. A cold front will be moving across northern New York during the late morning hours and across Vermont in the afternoon. Mixing will take place with this front and wind gusts in the 25 to 35 mph range can be expected with temperatures gradually falling behind the front. Temperatures will be warm enough for precipitation to mainly be in the form of rain showers...but change to snow showers later in the day. Snow squall parameter suggests there could be a convective element to the showers Friday afternoon...but temperatures should be warm enough for precipitation to be more rain showers than snow showers. chance for these convective showers will be from the Champlain Valley eastward Friday afternoon. Precipitation quickly comes to an end Friday night as the cold front moves east of the region and high pressure builds in. Lows Friday night will be in the mid teens to mid 20s with winds gradually tapering off and clouds slowly decreasing in areal coverage.ield gusty surface winds of 25-35 mph during Friday afternoon. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... As of 248 PM EST Thursday...Saturday will be dry over the area as large-scale ridging builds in. Post-frontal clearing will allow for partly to mostly sunny skies during the daytime hours. 850 mb temps will start off cold behind the front Saturday morning (generally -6 to -7 deg C), but warm air advection will develop during the day. By Saturday night, 850 temps will have risen to near 0 deg C. In terms of sensible weather, this means a chilly morning with improvement throughout the day as temps top out in the mid to upper 30s. Clouds will begin to increase Saturday evening through Saturday night as a coastal low pressure system rides up the Mid Atlantic Coast. Overnight lows will be occur early for most of the area, with near constant or slightly rising temperatures forecast through the night. Lows will be in the mid to upper 20s. The exception will be the Northeast Kingdom of Vermont, where clouds will be later to arrive and potential for radiational cooling is the greatest. This area will reach lows in the upper teens to low 20s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 248 PM EST Thursday...Most challenging part of the long term forecast continues to be a low pressure system that will track from the Mid-Atlantic Coast to off the New England Coast Sunday. Still a variety of solutions among the models as to the exact track of the low, which makes for a difficult precipitation forecast given that we`ll be on the northwestern periphery of the system. The trend in the 12Z deterministic model suite for both the NAM and the ECMWF has been to track the system further south and east, while the CMC and the GFS are holding onto a more coastal track that would result in more precipitation for our area. Given the wide range of solutions on the track, it`s difficult to go into specifics at this point on the storm. In terms of impacts, driest solution (NAM) would keep any precipitation associated with the system out of our forecast area, while the most bullish, furthest west solutions (CMC and GFS) would bring just a few inches of wrap-around snow to our area. Given the fast-moving nature of the system (open wave aloft), not concerned at this point for anything more than a few inches of snow or rain/snow mix in Vermont/northern NY, but will adjust forecast if anything changes. Best chances for accumulations will be in southern Vermont and along western slopes of the Greens. Can`t rule out some mixed precipitation with the event either, but too early to have a handle of thermal profiles with the uncertain track. The system will exit the area Sunday night, followed by a dry start to the work week with high pressure building in. The next chance for widespread precipitation will be Wednesday as the next low pressure system tracks through the area. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Through 00Z Saturday...A mix of mainly VFR/MVFR over the next 24 hours as low pressure and associated cold front cross the region. Scattered shower activity associated with this feature generally expected in the 00-18Z time frame, though uncertainty in overall coverage warrants mainly VCSH in terminal forecasts at this point. Main concern overnight through mid-morning Friday will be southwesterly low level wind shear in the 35-50 kt range at all terminals. During this period expect moderate to occasionally robust mechanical turbulence on departures and approaches. Surface winds mainly light southerly through 06Z, increasing into the 10-18 kt range and trending gusty to 25 kts thereafter, backing to west/northwesterly in the 18-00Z time frame behind frontal passage. Outlook... Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. Saturday Night: VFR. Slight chance SN. Sunday: MVFR/IFR conditions possible. Chance SHSN, Chance SHRA. Sunday Night: Mainly IFR, with areas MVFR possible. Chance SHSN. Monday: Mainly MVFR, with local VFR possible. NO SIG WX. Monday Night: VFR. NO SIG WX. Tuesday: VFR. NO SIG WX. && .MARINE... South winds will be increasing this evening across Lake Champlain with south winds of 15 to 25 knots expected along with gusts to 30 knots at times. These conditions will continue through midday on Friday...then a cold front moves through and shifts winds to the west. Speeds will remain in the 15 to 25 knot range before slowly tapering off Friday night. Waves will build to 3 to 5 feet causing rather choppy conditions...especially over the northern portion of the lake later tonight through Friday morning...then across the eastern part of the lake when the winds shift to the west. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Banacos NEAR TERM...JMG/Evenson SHORT TERM...Duell LONG TERM...Duell AVIATION...JMG MARINE...Evenson
Area Forecast Discussion
National Weather Service Gray ME
1027 PM EST Thu Nov 21 2019 .SYNOPSIS... A brief period of freezing rain will be possible in the mountains and foothills later tonight, but it will be very light at best. A cold front moves through Friday afternoon with gusty winds following in its wake for Friday night into Saturday. Low pressure may affect the region on Sunday with mixed precipitation and rain, followed by high pressure early next week. && .NEAR TERM /THROUGH FRIDAY/... Update... Most recent update at 1028 to add an SPS for patchy mix southern areas per current radar trends. Light precipitation over eastern New York State will continue to move east per current radar imagery. Models suggest, most of the precipitation late tonight will be confined to the north and also be very light. While profiles indicate light rain and snow showers across northern portions of the region, there appears to be an increasing chance for some light freezing rain. Followed the HRRR POPS pretty closely this package. Have raised a Winter Weather Advisory for northern areas tonight for mixed precipitation, albeit it will be light. Prev Disc... High pressure centered over the area late this afternoon. Moisture is trapped under the subsidence inversion on the upwind (north) side of the mountains, with low clouds very stubborn to dissipate. As the high moves just east of us this evening, expect these low clouds to dissipate. Skies have been mostly clear south of the mountains and this should persist into the evening. Tonight and into early Friday a warm front moves through. Parent surface low is well off to the north and the system is quite moisture starved, so expect only light precip, mainly well inland. Mixed precip including light freezing rain is a concern along and north of the mountains, but at this point feel that precipitation is too light to warrant an advisory and hit it up in hazardous weather outlook instead. Strong cold front blasts through around midday Friday with gusty west winds behind the front and scattered showers, mainly as rain except snow in higher terrain. Temps falling late in the day. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... Cold airmass moves in Friday night and remaining breezy. Decreasing clouds south/downwind of the mountains but clouds and snow showers persisting along and north of the mountains. Less than 1 inch accumulation lower elevations of the north, with a couple inches of snow possible over the mountains, especially the Whites. High pressure late Saturday into Saturday night with cool temps and easing winds. Next potential system comes Sunday. Models gradually coming into better agreement on a Nor`easter track through the Gulf of Maine that will likely bring precipitation to at least the coastal plain and possibly north into the mountains as well. Temps could be cold enough for snow inland just a bit from immediate coast, so definitely something to watch. Far from a certainty at this point, but likely enough that went with likely PoPs. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Potential Nor`easter kicks out Sunday night, with high pressure Monday into early Tuesday. Airmass behind the Sunday system not that cool, with temps fairly close to average. Next potential system is Wednesday. Most models and model ensembles have a system, but vary greatly in timing and track. Did raise PoPs up to likely. System will likely have a more northern track than the Sunday system so if this system pans out, wintry precip would mainly be well inland. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... Short Term...VFR this evening except MVFR cigs persisting early evening north of the mountains. System late tonight and early Friday could bring MVFR cigs to northern TAF sites, but sites closer to the coast will mostly be VFR. Low level wind shear an issue at all TAF sites late tonight into early Friday. Gusty winds at the surface areawide late Friday. Long Term...Gusty winds persisting into Saturday, then easing. Mostly VFR Friday night into Saturday night, except perhaps MVFR or IFR persisting along/north of the mountains Friday night into early Saturday. Possibility for MVFR/IFR Sunday with potential Nor`easter. VFR likely Monday/Tuesday. && .MARINE... Short Term...Issued gale warning for strong west winds behind the cold front late Friday into Friday night. Seas in the neighborhood of 5 feet. Long Term...Nor`easter Sunday has the potential to bring gales depending on eventual track. Below small craft early next week. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Winter Weather Advisory until 8 AM EST Friday for MEZ007>009- 012>014. NH...Winter Weather Advisory until 8 AM EST Friday for NHZ001>005. MARINE...Gale Warning from 5 PM Friday to 5 AM EST Saturday for ANZ150>154. && $$
Area Forecast Discussion
National Weather Service Lincoln IL
903 PM CST Thu Nov 21 2019 .SYNOPSIS... Issued at 320 PM CST Thu Nov 21 2019 Colder air will arrive in the area tonight as a cold front departs to the east. Rain chances will linger in southeast Illinois tonight, mainly south of Interstate 70. Low temperatures will bottom out in the upper 20s and 30s tonight. A few light rain showers may linger over areas along and south of highway 50 on Friday morning, otherwise a dry day is expected on Friday with clearing skies. Temperatures will be cooler Friday with highs only in the low to mid 40s. && .UPDATE... Issued at 903 PM CST Thu Nov 21 2019 03z/9pm surface analysis shows a cold front slowly sinking southward toward the Ohio River...while high pressure builds into the Northern Plains. A cooler airmass continues to spill into central Illinois on brisk northwesterly winds, with current temps mainly in the lower to middle 40s. As short-wave energy over the Ozarks interacts with the departing frontal boundary, a secondary wave of light rain will track across southern Illinois tonight. Regional radar mosaic shows the rain S/SW of the St. Louis metro area tracking northeastward. Based on radar trends and latest HRRR forecast, it appears showers will reach the far SE KILX CWA by midnight then linger through the overnight hours. Have adjusted PoPs to go categorical along/south of a Robinson to Flora line...with slight chances as far north as a Paris to Taylorville line. Further north, cloudy and dry weather will prevail through the night. && .SHORT TERM...(This evening through Friday) ISSUED AT 320 PM CST Thu Nov 21 2019 The cold front will continue to push through eastern Illinois into early evening, with pressure rises helping to establish brisk NW winds in the wake of the front. Cold air advection will work to keep cloud cover in place overnight for a majority of the area. Some clearing could reach as far as the Illinois River Valley by sunrise on Friday, but clearing will mainly occur on Friday as dry mid-level air mixes out any residual boundary layer moisture. Temperatures on Friday will be much colder than Thursday, with highs ranging from the upper 30s north of Peoria, to the middle 40s south of I-70. Winds will be much lighter, but north winds at 5 to 10 mph will still add some chill to the air. .LONG TERM...(Friday night through Thursday) ISSUED AT 320 PM CST Thu Nov 21 2019 A southern jet stream low pressure system will progress from Louisiana to southern Ohio Friday night through Saturday, with an inverted trough extending north into central Illinois during that time. That trough will be the focus for rain and snow chances Friday night and Saturday across a large portion of central Illinois, with lower chances west and north of Peoria. Enough cold air will be in place at the onset of precipitation that any rain north of I-70 early Friday evening should transition to snow by mid to late evening. Even areas south of I-70 could switch over to snow for a time after midnight. Snow accumulations look to remain relatively light, a dusting to a half inch. However, slippery conditions could develop on any untreated roads Saturday morning, mainly for areas east of the Illinois River. Any lingering rain/snow showers Saturday afternoon should remain mainly east of I-57, and should transition all rain as the band of precipitation shifts east into Indiana. High temps on Saturday are expected to top out around 40 in most areas, somewhat cooler temps due to any potential snow cover. After a dry end to the weekend and start to next week, attention will turn to a potentially strong system for Tuesday into Wednesday of next week. The ECMWF did a significant change with the 12z run, coming more in line with the GFS, which shifted the low track much farther east than previous runs. The 12z Canadian- NH still indicates more of an open wave and limited precip during the time when the GFS and ECMWF show a deepening low tracking from Oklahoma across southeastern Illinois to Lake Erie Tuesday through Wednesday morning. There remains timing differences between the GFS and ECMWF, with the GFS about 6-9 hours faster than the ECMWF. The GFS has the surface low in southeast Illinois at 18z/Noon Tuesday, while the ECMWF has the low reaching that area between 00z/6pm and 03z/9pm Tuesday evening. The end result of that track would be much higher chances of precipitation, and an increased potential of measurable snowfall in at least the W half of our forecast area, roughly west of I-55. Due to such dramatic shifts with track of that low in both the GFS and ECMWF, we trended PoPs upward but kept them just below the likely category. We also trended colder with the introduction of snow chances in the forecast for our northern counties. We kept mainly rain south of I-74 for now. However, if the models continue to indicate the 12z low track, additional adjustments in snow coverage and amounts will be necessary. With Wednesday being a major travel day, any shift in the track of that low could largely alter travel conditions across Illinois. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 530 PM CST Thu Nov 21 2019 MVFR ceilings will persist at the central Illinois terminals through this evening before scattering late tonight into Friday morning. Based on forecast soundings, it appears ceilings will improve at KPIA by 08z...then further southeast to KCMI by around 14z. Skies will clear at the I-74 terminals by mid-morning, while SCT-BKN VFR ceilings will linger further south at KSPI/KDEC through 00z Sat. Northwesterly winds will initially gust 20-25kt early this evening, then will gradually decrease to 10-12kt after 03z/04z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Barnes SYNOPSIS...Shimon SHORT TERM...Shimon LONG TERM...Shimon AVIATION...Barnes
Area Forecast Discussion
National Weather Service Jackson MS
909 PM CST Thu Nov 21 2019 .UPDATE... Updated for evening discussion. && .DISCUSSION... Earlier showers across the Hwy 82 corridor have since moved east of the area into Alabama with the main area of precipitation confined to northern Mississippi. A surface cold front will continue pushing towards the region overnight, but the vast majority of the rainfall will remain north and west of the ArkLaMiss where better forcing will reside within a weak inverted prefrontal surface trough beneath favorable upper jet dynamics. A few isolated showers may brush northwest portions of the Delta overnight, but rain chances will remain low before ramping up just after daybreak. Overnight lows will remain mild in the mid 50s to low 60s owing to a well mixed boundary layer and cloudy skies. Only minor changes were needed to PoPs and temperatures. /TW/ Prior discussion below: Today and Tonight... Weak ridging over the southeastern CONUS is slowly losing ground to an upper low digging into the desert SW. That upper low and its developing surface low will be the main weather concern in the short term. A weak shortwave continues to bring light showers over the northern tier of the state this afternoon, but becoming more spotty in coverage overall. Southerly flow will continue into the overnight hours, both keeping the overnight low temperatures mild (60s in the west and 50s east of I-55) as well as pushing some moisture into the region ahead of an advancing front. The frontal boundary to the NW will settle into the region in the overnight hours, spreading precipitation into the north/northwestern portions of Mississippi and southeastern Arkansas after midnight. Friday will be an increasingly wet day with the progression of the front. Concerns after 18z and into Friday evening revolve around the potential for heavy rain. The front slows considerably as it moves into the region, getting caught up in parallel flow aloft out of the southwest. HRRR and NAM among others showing signs of continued development along the boundary...setting up for pockets of heavier QPF, with and without thunder. While theta E ridging and moisture transport is also supportive of rich RH, echoed in the forecast soundings and precipitable water values in the 1.5 to 2 inch range, there is a lack of significant upper level support in the jet for now. Front is still progressing slowly, and WPC is keeping JAN in a marginal risk for now. Friday night through next Wednesday night: The threat for locally heavy rainfall will continue into Friday night, and will gradually shift east of the area by early Saturday morning as rain chances begin to taper off quickly. Thereafter, seasonable to above normal temperatures are expected through the weekend into early next week with mostly dry conditions as largely zonal flow aloft allows mild Pacific air to have strong influence. Confidence in the rainfall forecast continues to be quite low beyond the weekend as various global models show quite a bit of variability from run-to-run. However, there is a trend toward a drier weather pattern as a system that has recently been indicated for around Tuesday looks less impressive, and the upper ridge for later in the week is looking stronger in our region. Will continue to indicate rain chances in the explicit forecast, but the risk for a highly impactful storm system seems to be diminishing. /EC/ && .AVIATION... 00Z TAF discussion: Mainly VFR conditions will prevail through tonight before both ceiling and visibility restrictions become widespread tomorrow. An area of showers continues to push east along the Hwy 82 corridor from GWO to GTR. This activity is expected to continue through 22/02z before moving east of the area into Alabama. Brief ceiling/visibility reductions can be expected with these showers. Overcast skies will continue overnight ahead of an advancing cold front with southerly winds around 6-10kts. Ceilings are expected to lower from northwest to southeast starting tomorrow morning in the Delta and spreading into the I-20 corridor by the afternoon. MVFR ceilings will be common with IFR expected at GLH/GWO/GTR. In addition, several rounds of showers and thunderstorms are expected along the cold front with reduced visibility owing to heavy rain. Winds are forecast to shift to out of the north behind the frontal passage at GLH/GWO late in the TAF period with wind shifts elsewhere occurring outside of the current TAF forecast period. /TW/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 58 74 52 62 / 4 95 99 42 Meridian 53 75 57 66 / 6 81 97 79 Vicksburg 63 75 51 62 / 4 97 98 19 Hattiesburg 55 78 59 67 / 2 65 81 83 Natchez 62 74 53 62 / 3 93 98 23 Greenville 62 67 46 57 / 16 87 91 14 Greenwood 61 69 48 57 / 14 96 96 20 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ TW/HJS/EC
Area Forecast Discussion
National Weather Service North Platte NE
544 PM CST Thu Nov 21 2019 .SHORT TERM...(This evening through Friday night) Issued at 311 PM CST Thu Nov 21 2019 The main concern in the short term period is with the chance of snow across southwest Nebraska and the low temperatures tonight. Late evening there is the potential for flurries to light snow, mainly after 9pm CT for southwest Nebraska. Did extend the snow chances slightly farther north, but still kept it across the southern portion of the CWA. The RAP model did try to hint at some snowfall farther north, but this seemed to be an outlier and trended more towards the EC and GFS. Also after collaboration from other offices adjusted the time of the snowfall a couple hours earlier as the system looks to approach the area a little sooner than expected. Forecaster confidence is low in coverage of snow chances but with forcing around the area, did not want to decrease chances. Confidence is moderate that little to no snow accumulation is expected tonight. Timing wise, snow chance will be limited with any snow chances ending by sunrise. As for lows overnight, increased lows slightly, mainly across the southern CWA, by a few degrees, as cloud coverage overnight should keep temperatures a little warmer. .LONG TERM...(Saturday through Thursday) Issued at 311 PM CST Thu Nov 21 2019 The main concern in the long term will be the potential for snowfall on Monday and Tuesday. At this time there is a lot of uncertainty with the track of the system. Earlier model runs brought the system across the high plains including portions of our western forecast area. That being said some of the latest model runs have shifted the track, bringing areas of greatest precipitation potential south of the forecast area. This will continue to be a system that we will monitor as we get closer the track of the storm should become a little more clear, but at this time forecaster confidence is low in the exact track. There is also the hint of another possible system on its heels for the end of the forecast period that could bring more precipitation chances. As for this weekend, temperatures will warm into the low 50s on Saturday and mid to upper 50s on Sunday. Saturday and Sunday will also remain dry with no concerns for precipitation. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 544 PM CST Thu Nov 21 2019 Mid level clouds are expected over the next couple hours, however, ceilings will remain in VFR conditions. Skies will gradually clear by early Friday morning with light winds prevailing through the remainder of the TAF forecast. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Gomez LONG TERM...Gomez AVIATION...Kulik
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
836 PM CST Thu Nov 21 2019 .UPDATE... 835 PM CST The main update for tonight was to extend cloudy conditions through early Friday morning, with some potential for clouds to linger through all of Friday morning in northwest Indiana and the far southern CWA. The area is entrenched in cyclonic, stratus-filled cold advection this evening, though the strongest thermal advection is just off the deck. Northwest wind gusts have eased slightly and temperatures are inching down into the 30s as of 830 pm. There has been some patchy drizzle over Chicago and far northwest Indiana associated with a secondary cold front/trough and associated low- level convergence. This should clear the area in a couple hours but the clouds will remain seeing there is plentiful clouds upstream on satellite. The 00Z DVN sounding showed clouds had a depth of about 2,500 ft. While the saturated depth was much thinner up at MPX with a stronger subsidence inversion shown, there still was a moist layer at the base of the inversion and upstream satellite trends are not particularly optimistic. Model moisture fields are not handling these clouds particularly well especially upstream and suspect that is due to the shallow nature of the clouds in that area. The forecast RAP and NAM soundings have a boundary layer profile that would likely still support a thin stratus over most of the CWA until daybreak. Some holes will probably gradually develop, but may take a handful of hours after sunrise before becoming mostly sunny, at least over eastern and southern parts of the CWA. No other noteworthy changes made as the thermal advection is driving the temperatures more than cloud cover vs clearing, so those look in good shape. MTF && .SHORT TERM... 248 PM CST Through Friday night... As of 230PM CST, the strong cold front is quickly pushing across the region, extending, roughly, from Chicago through Pontiac. Any lingering pcpn has ended, with south-southwesterly winds gusting up to 35 to 40 mph and temperatures into the mid 50s are ahead of the front. Winds are shifting to westerly immediately following the frontal passage and will then continue to veer to nwly early this evening. While peak gusts are ahead of the front, winds will remain gusty behind the front through much of the night as strong cold advection and strong pressure rises overspread the region as another arctic high pressure system builds across the Middle/Upper Mississippi Valley and to the Ohio Valley. Temperatures are also dropping off quickly following the frontal passage, with temperatures already dropping into the mid 40s west of I-39. Temperatures will continue to drop off rapidly through the evening even with overcast skies persisting until arnd midnight. latest forecast moisture profiles suggest that cloud cover should clear out late tonight. With winds remaining rather brisk through the night, radiative cooling will be minimal, but cold advection will drive overnight lows into the mid 20s around the Rockford area to the lower 30s across the remainder of the CWA. Friday should be sunny, but still cooler than normal with highs only in the middle to upper 30s, which is about 10 degrees below normal. Cloud cover should be on the increase Friday night, from south to north, as a deep upper low moves across the Central Plains to the Middle Mississippi Valley, setting up deep layer swly flow and a return fetch of moisture. However, any pcpn associated with this system will hold off until after the end of the short term period. && .LONG TERM... 301 PM CST Saturday through Thursday... At the start of the period Saturday morning the upper low, currently over the southwest CONUS, will be shifting eastward across the Mid-Mississippi valley. This upper level system is likely to drive an area of low pressure over the Ohio Valley Saturday afternoon and evening. While it appears that much of the moisture with this weather system will remain out of our area, there will be a chance for some light rain and/snow on Saturday, mainly over my far southeastern counties. Precipitation amounts look to remain low, so snow accumulations even in my far southeast would likely remain limited to under an inch. Later Saturday night and Sunday through Sunday night will be dry with near seasonable temperatures. Looking ahead to the abbreviated Thanksgiving work week and busy holiday travel period, forecast confidence remains very low, especially in regards to precipitation chances Tuesday into early Wednesday. With southwest flow and warm advection, Monday has a decent chance to have slightly above normal temps into the upper 40s to around 50. The jet stream pattern across North America will become quite active next week, so ingredients could come together to support a stronger storm system across the central CONUS sometime around the Tuesday into Wednesday. This continues to be hinted at by operational runs and several ensemble members. However, uncertainty remains far too high to be confident in any specifics. Recent runs of the operational forecast guidance have trended farther east with the track of a potential storm system over the region next Tuesday into Wednesday. In fact, the most recent 12z runs of both the GFS and ECMWF would be very concerning for our area Tuesday into Wednesday for snow and wind. However, due to the wide spread in ensemble guidance and the large fluctuations in guidance over the past few days, it is clear that at this time range there is lower predictability in how the atmospheric will evolve over the region. For this reason, it is hard to envision the model solutions not continuing to waver significantly in subsequence runs. Until a better depiction of the storm system next week is obtained, we will continue with chance POPs over the area. Castro/KJB KJB && .AVIATION... For the 00Z TAFs... The front which pushed through the area today is now well east of the terminals, with westerly winds in place. Winds will remain gusty for much of the night, however, will not be nearly as strong as earlier today. Winds will become more northwest on Friday, while diminishing. Expect MVFR ceilings to be in place for much of tonight and possibly into Friday morning, as good amount of lower level moisture is in place overhead and upstream. Skies should clear during the day on Friday, with VFR and dry conditions then expected. Rodriguez && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...Small Craft Advisory...Gary to Michigan City IN until 3 PM Friday. Small Craft Advisory...Winthrop Harbor to Gary IN until 10 AM Friday. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
853 PM CST Thu Nov 21 2019 .UPDATE... Issued at 838 PM CST Thu Nov 21 2019 Radar and latest surface observations is showing the rain moving into the southern part of the CWA. This is consistent with the going forecast and the latest runs of the RAP which have notable moisture convergence along and south of I-70 late this evening into the overnight hours. Upped PoPs this evening based on going trends, and forecast of rain exiting the CWA late tonight/early Friday still looks good based on the RAP moving the low level forcing/moisture out during this time frame. Britt && .SHORT TERM... (Through Saturday Morning) Issued at 316 PM CST Thu Nov 21 2019 The middle Mississippi Valley is currently situated between a sharp upper trough extending from the Hudson Bay into the Upper Midwest and a broad closed upper low over the Desert Southwest. A cold front associated with the upper trough to the NE is passing through the region with the upper portions of that front extending north well into the forecast area. A shortwave will eject into the Midwest/mid-South tonight, enhancing mid and low level forcing along the stalling front, igniting another round of widespread precip along the baroclinic zone. Precipitation is very likely across southern MO and IL, with the northern extent of the precip determined by the advance of cool, dry air behind the front. Forecast guidance has zeroed in on roughly the I-70 corridor as the delineator between a wet and dry forecast overnight. As the shortwave kicks east of the region on Friday, cool and dry air will continue to move further south into the area. This dryness, coupled will weak subsidence behind the departing shortwave, will keep a lid on precip chances on Friday. It will also result in considerably cooler temperatures on Friday, despite gradually clearing skies across much of the forecast area. Meanwhile, the southwest cutoff low will approach the region. This will deepen a surface trough across OK and AR, which in turn will shunt the baroclinic zone back into southern MO and IL beginning late Friday afternoon. The forcing along the front, along the the DCVA provided by the upper low, will likely be sufficient to result in additional precipitation. Forecast guidance is slowly coming into consensus on the precip on Friday night and Saturday morning. Many of the deterministic and ensemble members are pushing measurable precip across nearly the entire forecast area, with several forecasts showing the highest amounts in excess of 0.2" of liquid into SE MO and southern IL. With cooler air continuing to filter into the region, thermal profiles appear to be supportive of light wintry precipitation on Saturday morning. A mix of rain and snow appears to be the most likely precip types, but we`re beginning to see subtle hints that a small amount of freezing rain may even mix in. Given the marginal thermal profiles and warm ground, I don`t expect to see much more than up to a half an inch of snow on grassy and elevated surfaces. BSH .LONG TERM... (Saturday through Next Thursday) Issued at 316 PM CST Thu Nov 21 2019 Dry NW upper level flow will take over by Saturday as surface high pressure begins to build into the area. This will result in dry weather, with continued cool temps on Saturday and warming temps on Sunday and Monday thanks to increasing southerly winds. The pattern is then expected to turn more active by Tuesday as an upper level trough moves into the region. Uncertainty on forecast specifics is fairly high given considerable model spread, but this pattern is most likely to result in precipitation across the region. Fortunately the bulk ensemble guidance keeps temperatures largely above freezing during this period, so chances for wintry precip in the mid-Mississippi Valley appears to be rather low. On the other side of that coin, CIPS severe analogs have been creeping a small risk of severe weather into the region on Tuesday, which depending on how robust of a system develops, is not out of the question. Dry NW flow is then expected to build back into the region by the end of next week, resulting in another period of quiet weather. BSH && .AVIATION... (For the 00z TAFs through 00z Friday Evening) Issued at 531 PM CST Thu Nov 21 2019 Overcast ceilings between 1500-2500FT AGL are expected through 09-12Z at KUIN/KCOU and the St. Louis area terminals through late tomorrow morning. Rain currently over southwest Missouri is expected to move into northeast into parts of eastern Missouri and southwest Illinois later tonight into early Friday including the St. Louis area terminals. The rain is expected to move out of the area by mid morning and VFR conditions are expected by Friday afternoon. SPECIFICS FOR KSTL: Overcast ceilings between 1500-2500FT AGL are expected through late tomorrow morning. Rain currently over southwest Missouri is expected to move into terminal late tonight. The rain is expected to move out of the area by mid morning and VFR conditions are expected by Friday afternoon. Additional rain with MVFR conditions will move back into the airport late tomorrow evening. Britt && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
629 PM CST Thu Nov 21 2019 .UPDATE... Quick update sent out to increase PoPs across the western South Plains to 100 percent since the coverage is there, models show the lien remaining filled in, and the biggest change was to add mention of small hail for the isolated thunderstorms moving in from New Mexico. No reports have been received yet of graupel with the stronger storms but dual-pol products from KFDX show the possibility of small hail/graupel mixed in. Also had to adjust temperatures down in the northwest where WTX Mesonet sites show readings between 34 to 36 degrees which was 6-8 degrees cooler than the current forecast had. This may help graupel reach the ground but do not expect any other wintry precipitation as dewpoints are 34-35 degrees so there is little room to wet-bulb cool temperatures below freezing. Jordan && .PREV DISCUSSION... /issued 535 PM CST Thu Nov 21 2019/ AVIATION... Confidence in this TAF forecast is low due to numerous issues faced at the terminals. MVFR ceilings continue at all three TAF sites and expect these to gradually fall into high IFR at KLBB/KPVW. KCDS may remain MVFR through the night and occasionally bounce down into IFR. That is the first issue...what will ceilings do through the forecast. Will carry IFR at KLBB/KPVW later tonight through early morning with a gradual increase back into MVFR for the day Friday. Next issue is area of showers with embedded thunderstorms west of the terminals moving east with time. Expect these to continue to move east and impact KLBB/KPVW this evening. Chances for thunder will likely be minimal as activity moves over colder airmass in place at the terminals but will need to watch for updates to include TEMPO for -TSRA if we continue to see lightning strikes on detection networks. Precipitation will end from west to east through the overnight hours into Friday morning with IFR conditions continuing. Ceilings will rise back into MVFR range for KLBB/KPVW Friday afternoon but confidence is low on when this may take place. Expect amendments through the next 6 hours as forecast becomes clearer with time. Jordan PREV DISCUSSION... /issued 239 PM CST Thu Nov 21 2019/ DISCUSSION... Isolated showers continue to move across the county warning area (CWA) this afternoon, and are rooted above the shallow cold front that sagged through the region earlier today. These non-surface based showers will continue throughout the remainder of the afternoon and into the evening. Latest GOES-East water vapor imagery and real-time RAP analysis indicates a broadening upper-level low pivoting across the Desert Southwest and into the southwestern Great Plains. Broad, mid-level cyclonic flow ahead of this low becomes largely diffluent as it ejects into the western Great Plains. As the longwave trough and associated cold core low migrate east, it will gradually become an elongated, open wave resulting in weak synoptic-scale forcing and meager isentropic ascent across the CWA. This will promote the potential for light rain tonight over West Texas. The passage of the surface cold front has also shunted any re-development of an elevated mixed layer; therefore, thunder is not expected as updrafts will not reach heights high enough to generate lightning. Precipitation is expected to remain liquid across the entire CWA overnight, and confidence is low for any potential of light snow in the northwestern areas of the CWA. The thermodynamic profiles will be saturated from the surface-to-mid-levels, and therefore supersaturated with respect to ice in the planar crystal growth zone; however, the depth of the warm nose in the low-levels should prevent any potential for snow in the northwestern South Plains and far southwestern Texas Panhandle (even if sufficient wet-bulbing does occur down to the surface, any light snow mixed with rain will have minimal-to-no impacts for commuters). However, overnight temperatures are expected to fall into the lower 30s across the northwestern portions of the CWA by early Friday morning. Any wet surfaces, irrespective of precipitation type that occurs, may become slick should temperatures reach freezing. After sunrise, temperatures will gradually warm into lower and upper 40s across the northern and southern zones, respectively. Skies will also become clear by the late afternoon hours Friday. Heading into the weekend, daytime high temperatures will rebound into the upper 50s and lower 60s across the CWA with plentiful sunshine. Winds will shift to the west by Sunday, and the compressional warming will result in temperatures warming into the 60s area-wide on Sunday and Monday. For the extended period, there is increasing consensus for another longwave trough to pivot inland off of the Pacific coast and into the Desert Southwest region given an already active northern hemispheric wavenumber pattern. While it is too soon to iron out any details, as always, any potential for cyclonic flow over our area can result in the possibility of active weather. Stay tuned to subsequent forecast products over the next couple of days for more information regarding this next potential event. Sincavage && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 14/58
Area Forecast Discussion
National Weather Service Marquette MI
652 PM EST Thu Nov 21 2019 .SHORT TERM...(This evening through Friday) Issued at 410 PM EST THU NOV 21 2019 WV imagery and RAP analysis indicated a mid/upper level trough from Hudson Bay through northwest Ontario into South Dakota. The vigorous shortwave that supported the heavier precipitation earlier today was lifting quickly northeast from northern lower Michigan. At the surface, a 998 mb low was located just north of the Sault with a cold front through eastern Upper Michigan into Lake Michigan. CAA behind the front has changed the rain to snow over the west half while some rain or ra/sn mix continued over the east. 850 mb temps from -8C west to -3C central along with cyclonic northerly flow and deep moisture over the area supported lake enhanced snow near Lake Superior over the west half downstream from 320-330 winds. In addition, winds were gusting to 30-40 mph over the Keweenaw. Fortunately, the snow has been wet enough to reduce blsn. Tonight, continued CAA will drop 850 mb temps to around -11C by 06z. However, the diminishing 850-700 mb moisture will result in a continued decrease in snow intensity over the north so that mainly just light snow showers are flurries are expected after midnight. Additional accumulations around an inch will be possible. The longer fetch into the east and later moisture departure could support 1 to 2 inch amounts from Alger county eastward. Northwest winds gusting to near 40 knots will produce waves of 12-14 feet over the east where lakeshore flooding/erosion is expected. As the gusty northwest winds to 25 mph temps will slowly fall into the upper teens west to the mid 20s east. Friday, sfc ridging building toward the area will bring backing winds to west and southwest with quickly falling inversion heights that should bring an end to any lingering -shsn by mid to late morning. Dry air moving in from the plains will bring some welcome clearing and sunshine by afternoon as temps climb into the lower 30s. .LONG TERM...(Friday night through Thursday) Issued at 403 PM EST THU NOV 21 2019 Upper-level ridging will be in control Friday evening, but with the next short wave approaching, the height gradient will increase and lead to an increase in the wind for Friday night, both on land and water Friday night. This will especially be true in the downslope areas around MQT where a 40-50 kt LLJ sitting above 1-2 kft AGL should help some gusts of at least 25 mph (and maybe higher) to mix down. Also hedged warm on temps by a few degrees (towards the model ensemble 75th percentile, since the bias-corrected guidance is distinctly colder than the raw guidance). Lows should end up mostly in the lower to mid 20s. The only fly in the ointment is that skies will be clear, so anywhere winds do go light we could see temps drop below forecast, but overall expect the wind and mixed low levels to dominate temps. For Sunday through early next week, there will be numerous short waves in play in quasi-zonal split flow. The GFs and EC seem to agree on one quick wave moving through the area on Sunday, so thought increasing POPs to chance over the Keweenaw was warranted (the wave looks to stay mostly to our north). The next wave to watch will be on Monday. Models disagree on how quick it will amplify. This does not look like any sort of significant system either way, but could be some light rain or snow Monday night. The air behind this system should be cold enough to support some modest lake-effect precip (850 mb temps -7 to -10 C or so atop Lake Superior`s sfc temps around 5 C) so depending on how exactly this system plays out, there could be some light snow showers as well Monday night and continuing into Tuesday in the NW wind LES belts. Now, what you`ve all been waiting for... our feature presentation. Already it seems a lot of talk has been made about a potential strong storm next week - and it probably shouldn`t have been. There continues to be very poor model consensus in this time frame with the GFS being the lone hold-out of the deterministic models for significant snow in the U.P., and even its 12z run continues the trend south and east. In preparation for carving the Thanksgiving day turkey, I practiced by carving back POPs significantly during this period so that now they are all chance and lower (no likely). There are still a few ensemble members for each modeling center`s respective suite that would make things interesting, but overall the trend is away from any significant impacts in the U.P. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 651 PM EST THU NOV 21 2019 With a low pres system exiting to the e, lingering -sn at KIWD/KCMX/KSAW will continue to diminish and then end tonight. At KIWD/KSAW, expect MVFR cigs to prevail thru the night. Clouds will then clear out Fri morning if not a little earlier as backing winds and drying/warming air mass clear out lower clouds. Expect similar conditions and trends at KCMX, though it may not be until late Fri morning/early aftn before clouds clear out. Gusty nnw winds to 20- 30kt this evening, mainly at KCMX/KSAW and strongest at KCMX, will also diminish thru the night. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 410 PM EST THU NOV 21 2019 Northwest gales to 40 knots will continue this evening and drop to 30 knots late tonight as a deep low east of Lake Superior lifts away to the northeast. Winds will diminish to around 25 knots by Friday afternoon before increasing to 35 knots wsw gales Friday night. Winds will then relax below 20 knots Saturday evening through Tuesday morning. There is a chance for another low pressure system to develop and cross Lake Superior Wednesday evening through Thursday, but strength and track of the low remain uncertain. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory until 7 PM EST /6 PM CST/ this evening for MIZ001>004-009-084. Lakeshore Flood Advisory until 4 AM EST Friday for MIZ006-007. Lake Superior... Gale Warning until 4 AM EST Friday for LSZ249>251-266-267. Gale Warning until 1 AM EST Friday for LSZ244-245-248-264-265. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...RJC AVIATION...Rolfson MARINE...JLB
Area Forecast Discussion
National Weather Service Nashville TN
826 PM CST Thu Nov 21 2019 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Showers are having a difficult time materializing thus far, owing primarily to a dry boundary layer. The 00Z sounding from OHX shows plenty of moisture above 850 mb, but some of that moisture is going to have to work its way down to the surface before we can sustain measurable precipitation. At this time, a cold front is slowly approaching Middle Tennessee from the NW, but hasn`t quite reached PAH. This front will sag across the mid state tomorrow and should exit the region by sunset. Radar imagery does show echoes starting to develop over West Tennessee, and the HRRR does bring more widespread activity across the Tennessee River after midnight. In the meantime, look for only spotty showers the remainder of the evening. Hourly forecast grids are holding up reasonably well with only minor tinkering here and there. Will re- issue the public forecast shortly just to update the wording. No appreciable changes are planned for now. && .AVIATION... 00Z TAF DISCUSSION. CKV/BNA/MQY/CSV...Several admendments possible thru 22/24Z. VCSH terminals thru at least 22/04Z. Heavy rain possible CKV 22/07Z-22/12Z. Mdt rainfall possible all terminals 22/10Z-22/18Z. Initial VFR/MVFR ceilings approaching 22/00Z will fluctuate between LIFR/IFR/MVFR ceilings by as early as 22/04Z CKV. Fluctuations between VFR/MVFR/IFR vsbys thru 22/24Z possible. Ahead of sfc frontal passage, S/SW sfc sustained winds 5-10 kts expected to prevail. N sfc winds 5-10kts expected behind passage. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......JB Wright AVIATION........08