Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/22/18

Area Forecast Discussion
National Weather Service La Crosse WI
535 PM CST Wed Nov 21 2018 .SHORT TERM...(This evening through Thanksgiving) Issued at 330 PM CST Wed Nov 21 2018 At 3 PM, there was 2 frontogenetic snow bands located across the Upper Mississippi River Valley. The first band is located along and east of the Mississippi River. This band reduced visibilities to as low as 3 miles at Winona and 2.5 miles at La Crosse. Both Holmen and our office measured a tenth of an inch of snow. Elsewhere, only received snow reports of a trace. The RAP shows that this forcing will continue to gradually weaken for the remainder of the afternoon. The second band of snow is located north of Interstate 94. Observations have showed no visibility restrictions with this band, so there is likely only flurries associated with this one. From late this evening into Thanksgiving morning, the RAP continues to show that the 800 to 700 mb frontogenesis will once again increase across Wisconsin. Unlike this afternoon, there will be a loss of ice aloft, so any precipitation that falls would be liquid. With cold road surfaces, there is a concern for freezing drizzle. However, there are plenty of questions on whether any precipitation will even occur due to the moisture being shallow across the area and dry air be located in the lowest 2,000 feet. For now, left the freezing drizzle out of the forecast and will continue to monitor conditions upstream. .LONG TERM...(Thursday night through Wednesday) Issued at 330 PM CST Wed Nov 21 2018 From Friday into Saturday morning, a shortwave trough will move east through the region. As this wave approaches, the atmosphere will quickly moisten. Temperatures aloft will be warm enough for the precipitation to remain mainly as liquid. This is of concern initially because of the cold road temperatures. If the rain occurs early on Friday, there could be some freezing rain at the onset. If it does not move into the area until the latter part of the morning (like it looks now), the roads will have a chance to warm enough that the precipitation will be just rain. From Saturday night into Sunday night, the models continue to struggle on the track of a deepening low pressure area. Both the 21.12z GFS and Canadian shifted south with their track and they now produce very little snow at all in the area. Meanwhile, the operational ECMWF which has been consistently showing its heaviest snow just south and southeast of the area has now shifted its heaviest snow band further to the northwest. This results in more snow for northeast Iowa and along and south of Interstate 90 in western Wisconsin. However, the ECMWF ensemble members still show a widely diverse set of solutions ranging from the low tracking as far as west as Interstate 35 to Cleveland Ohio. As a result, the confidence in the track of this system remains low at this time. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 535 PM CST Wed Nov 21 2018 Cigs: lowering mvfr/ifr cigs expected later this evening/overnight, associated with low level warm air advection tied to an approaching sfc warm front. Low cigs should hang around for much of Thu, with improvement (per bufkit soundings) progged Thu evening. WX/vsby: some hints in the low level frontogenetic fields that there could be enough lift in the low saturation to trigger some light -sn or flurries overnight-Thu morning. As of now, most of this lift looks to be northeast of I-94, with no impact for the TAF sites. Winds: mostly southeast, becoming a bit more south later in the day Thu. Increasing pressure gradient will keep winds stirred overnight, through Thu. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Boyne LONG TERM...Boyne AVIATION...Rieck
Area Forecast Discussion
National Weather Service Bismarck ND
848 PM CST Wed Nov 21 2018 .UPDATE... Issued at 844 PM CST Wed Nov 21 2018 Blended in current observations and trends, and the forecast remains on track. The western edge of the fog has remained stationary over the past few hours. Visibility remains poor from northwest to south central ND. UPDATE Issued at 605 PM CST Wed Nov 21 2018 We have expanded the Dense Fog Advisory farther west to cover McKenzie, Dunn, Stark, Hettinger, and Adams Counties. Satellite imagery has shown a rather quick westward expansion of fog over the past few hours, which was suggested by recent HRRR solutions. Confidence on how long fog will last out west is low. Hi-res guidance shows the fog retreating back east after 06Z, while NAM- based solutions keep all but far western ND socked in through Thanksgiving morning. Otherwise, the forecast remains on track. && .SHORT TERM...(This evening through Thursday) Issued at 242 PM CST Wed Nov 21 2018 A Dense Fog Advisory for the northwest through south-central this afternoon through early Thursday morning highlights the short term forecast period. Upper level ridging will develop over the forecast area tonight. Subsidence and persistent low level moisture will continue our stratus/fog pattern through the short term. This afternoon, visibility in areas of the north central and northwest has been between one half mile and two miles. With areas of the south- central around one to four miles. Forecast soundings are consistent in redeveloping dense fog in these areas tonight. As the upper level ridge axis shifts from west to east, there is a good potential for dense fog to develop eastward including the James River Valley through the north- central. These areas will need to be monitored for a possible expansion of the advisory. The challenge Thanksgiving lies within cloud cover, persistence of fog, and how warm temperatures get through the day. The upper level ridge shifts to the east upstream of a trough over the Rockies. A warm front redevelops and pushes into the southwest. High temperatures are a bit of a challenge as skies are expected to be clear in the southwest and stay mostly cloudy east, with some uncertainty on how much clearing can occur central. Low 50s southwest can be expected with 30s in the James River Valley to 30s across the north and down to the upper 20s in the Turtle Mountains. If the sun can break through in the central, temperatures could look to rise into the low to mid 40s. Kept a mention of patchy fog across the forecast area through the day Thursday as the upper level ridge drifts overhead. Uncertainty in duration and location is low for the moment and will need to be refined tonight. .LONG TERM...(Thursday night through Wednesday) Issued at 242 PM CST Wed Nov 21 2018 A cooling trend beginning this weekend and several chances for snow highlight the long term period. With the upper level ridge moving eastward Thursday night, a weak shortwave moves overhead with a secondary wave and stronger cold front arriving Friday afternoon. Cold air advection intensifies Friday night through Saturday, leaving mild temperatures in the 30s and 40s ahead of the frontal passage on Friday. Temperatures cool off for the weekend with highs mostly in the 20s on Saturday and teens and 20s on Sunday. The ECMWF/GFS advertises a clipper moving to our south Saturday through Saturday night. With the NAM being the northward outlier in bringing QPF to our southern counties, we opted to keep the forecast dry for now. Ensemble model guidance indicates an active northwest pattern with a series of cold fronts Sunday through mid-week. Highs in the teens and 20s and lows in the single digits to teens can be expected as well as chances for snow Sunday night and Wednesday. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 605 PM CST Wed Nov 21 2018 Dense fog is expected at most TAF sites into Thursday morning, producing LIFR conditions. KISN may escape the fog altogether, but it will likely be a close call. Fog is expected to dissipate from west to east late Thursday morning into the early afternoon. Once the fog dissipates, expect VFR conditions through the remainder of the forecast period, except at KJMS where MVFR to IFR ceilings/ visibilities will continue. Expect southeast to southwest winds around 5 to 10 kts through Thursday afternoon. && .BIS WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 9 AM CST /8 AM MST/ Thursday for NDZ001>004-009>012-019>022-034>036-042-045>047-050. Dense Fog Advisory until 6 AM CST /5 AM MST/ Thursday for NDZ017- 018-033-041-044. && $$ UPDATE...MJ SHORT TERM...AE LONG TERM...AE AVIATION...Hollan
Area Forecast Discussion
National Weather Service Boston/Norton MA
1017 PM EST Wed Nov 21 2018 .SYNOPSIS... An arctic front sweeps through region by early evening followed by record cold and bitter cold wind chills tonight into Thanksgiving. High pressure moving off the coast will allow temperatures to moderate some on Friday and particularly on Saturday. Dry weather should prevail most of the day Saturday, but a fast moving low pressure system will bring a period of rain Saturday night with a low risk it may begin as some ice across portions of the interior. The rain may linger into the first part of Sunday before coming to an end. A potentially stronger low pressure system may bring more unsettled weather by Monday and/or Tuesday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 1015 pm update... The cold front has moved off the coast sitting between the Cape and Nantucket this evening based on satellite and surface observations showing post frontal dewpoints have dropped to the single digits. Given our cold temps come from good CAA, we`re likely to see a midnight high for any Thanksgiving climate records. Based on current observations Worcester, Providence, and Hartford will break their record low High temperature for Thanksgiving, while Boston still has several degrees to go. 7 PM Update... Bands of SHSN/SHRA have outpaced the parent front and as a result continue to dissipate as they push toward the SE coastlines. The front itself is just about at the BOS-PVD corridor at the time of this writing. Quick burst of 40-50 mph will accompany this passage but then settle back down to 20-30 mph ushering in the very dry, very cold airmass as advertised. Timed the front/POPs a little closer to current trends otherwise, forecast remains on track. Previous discussion follows... Scattered snow showers with localized brief heavy squalls moving into western MA. Decent low level convergence along the arctic front and low level moisture will allow these snow showers to move across SNE with hi-res guidance indicating a few snow showers reaching the coast late afternoon and early evening. RAP is showing higher 0-3km lapse rates making it into northern MA so an isolated brief heavy snow squall is possible. In addition, soundings indicate potential for brief 40-50 mph gusts right behind the front, especially over higher terrain. Clearing tonight with strong cold advection delivering a bitter cold airmass for this time of year. 850 mb temps down to -20C by 12z Thu. Followed a blend of raw model temps which yields record lows in the single numbers interior high terrain and low to mid teens elsewhere. The gusty winds will result in wind chills bottoming out between zero and -10F late tonight and Thu morning, and as low as -15F for the Berkshires where wind chill advisories are posted. NW winds will gust to 25-35 mph at times tonight. The arctic air will lead to extreme instability developing over the ocean late tonight with delta T of 30C from SST to top of the boundary layer. 320 trajectory will keep bulk of ocean effect snow showers offshore but can`t rule out some flurries late tonight over outer Cape. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... Thursday... Bitter cold Thanksgiving with core of coldest 850 mb air across SNE with -20 to -22C across SNE. Despite sunshine, highs will only reach mid teens to lower 20s. This will shatter record low maxes for the day. Gusty NW winds with max wind chills only recovering to single numbers and near zero over higher elevations. Ocean effect clouds and flurries will likely continue over the outer Cape. Thursday night... As low level winds veer to 330-340 degrees, potential for ocean effect snow showers over outer Cape will increase. Deep boundary layer with extreme instability over the ocean will persist through at least the first half of the night with ocean induced Capes around 1000 J/kg so some minor accumulations are possible. Subsidence inversion lowers overnight as the high builds in which will weaken ocean effect bands. Otherwise, clear skies rest of SNE and diminishing wind in the interior will result in another very cold night. Lows zero to 10 above across much of the region, except teens along the coast. More record lows may fall. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Highlights... * Ocean effect snow showers/flurries may clip outer-Cape into Fri am * Dry Fri into part of Sat with moderating temperatures * Period of rain Sat night perhaps lingering into part of Sun with a low risk it may begin as a period of ice across the interior * Another round of unsettled weather likely Mon and/or Tue with odds favoring ptype mainly rain but that is not set in stone Overview and model preferences... With a PNA shift toward neutral late week, the ridge tied to the Continental Divide will finally reach the E coast Fri into Sat as strong arctic vortex shifts toward Newfoundland and Labrador. While this will allow for gradual temperature moderation, especially as H85/H92 temperature anomalies become positive, there is enough lower lvl cold air to keep temps mainly below normal Fri and Sat. A weak S stream trof moves E across the CONUS by Sun, with developing low pres well to the S and dying low pres shifting into QC. In between these features will likely be an region of general subsidence, which could fall across New England. Therefore, feel the risk for heaviest precip will remain to the S with the developing offshore low pres. Primary concern would be sfc temps by the time of precip onset Sun morning. Focus then shifts on whether or not phasing of a wave wrapped up currently in the Aleutian vortex and an active wave near Nunavut are occurs for early next week. With little sampling and typical model struggles there is some uncertainty here. Agree with the previous forecaster that the antecedent airmass should have moderated enough to support mostly rain, but that it will depend on the potential phase, lack thereof, and/or whether there is strong offshore intensification. Will continue with the general consensus blend of guidance with this update. Details... Fri into Sat... Mid and upper lvl ridging will lead to mainly dry conditions through the period. While low-mid lvl temps will warm with this ridging (H85 temps rebound quickly Fri, reaching -3C by 00Z Sat, then an average around +3C on 00Z Sun) the near sfc layer (below H85) remains inverted suggesting that temps will remain below normal each day. Fri will likely only reach the upper 20s to mid 30s, certainly milder than Thu, but still well below. Sat milder still, with highs mainly in the upper 30s to low 40s. Sat night into Sun... Long occlusion with low pres development to the S. How close a low or mesolow gets to the S coast remains a question mark but given the overall system has Gulf of Mexico moisture associated with it (PWATs nearing 1.20in) some precipitation can be expected across S New England. Will need to watch the earl AM sfc temperatures closely as there is a low risk that some FZRA could fall until the BL can warm diurnally during the day on Sun. This is most likely in the valley of NW and N central MA given current trends. Otherwise, another steady rainfall with milder temps for Sun. Sun night into early Mon... Weak ridging follows this first shortwave and attendant low pres passages. Temps remain near normal. Tue into Wed... As mentioned above there is high uncertainty with this portion of the forecast. Favorable for unsettled or wet conditions. Most GEFS/ECMWF EPS members favor a mostly rain solution this will have to be watched as coastal low pres development is in play. Should it occur and rapidly deepen close by conditions could change. Too early to determine any forecast specifics. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Thursday Night/...High Confidence. Through 02Z... Lingering SHSN/SHRA dissipate with a brief gust 35-45 kt out of the W possible especially across RI/SE MA terminals. Tonight through Thursday night... Mainly VFR, but areas of MVFR cigs developing over the outer Cape late tonight into Thu night. A few flurries possible at times over the outer Cape with a period of steadier snow showers possible Thu night. NW gusts to 25-35 kt at times through Thursday, diminishing Thu night. KBOS Terminal... High confidence. KBDL Terminal... High confidence. Outlook /Friday through Monday/... Friday and Friday Night: VFR. Saturday: Mainly VFR. Saturday Night: Mainly MVFR, with local IFR possible. Windy with local gusts to 30 kt. RA likely. Sunday: Mainly MVFR, with local IFR possible. Windy with local gusts to 30 kt. Chance RA. Sunday Night: Mainly MVFR, with areas IFR possible. Breezy. Chance RA. Monday: Mainly MVFR, with areas IFR possible. Breezy. RA likely. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Thursday Night/...High confidence. NW gales with gusts 35-40 kt expected tonight through Thu. Winds slowly diminish Thu night. Vsbys may be reduced at times in snow showers late tonight into Thu night across waters east and NE of Cape Cod. Outlook /Friday through Monday/... Friday: Winds less than 25 kt. Seas locally approaching 5 ft. Friday Night: and Saturday: Winds less than 25 kt. Chance of rain showers. Saturday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Rain likely. Sunday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 9 ft. Chance of rain. Sunday Night: Winds less than 25 kt. Rough seas up to 9 ft. Chance of rain. Monday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 12 ft. Rain likely. && .CLIMATE... An early season shot of arctic air will likely result in some records being broken Thanksgiving into early Friday morning. November 22nd Location / Record Low / Record Minimum High Boston..........9 (1879) / 24 (1880) Hartford.......14 (1969) / 27 (1978) Providence.....16 (1987) / 30 (2008) Worcester......11 (1987) / 24 (2008) Thanksgiving Location / Record Low / Record Minimum High Boston.........11 (Nov 27, 1873) / 24 (Nov 28, 1901) Hartford.......12 (Nov 28, 2002) / 27 (Nov 23, 1989) Providence.....14 (Nov 23, 1972) / 30 (Nov 28, 1996) Worcester.......9 (Nov 23, 1989) / 22 (Nov 23, 1989) November 23rd Location / Record Low Boston.........11 (1880) Hartford.......12 (1972) Providence.....14 (1972) Worcester.......9 (1989) && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...Wind Chill Advisory from 4 AM to 10 AM EST Thursday for MAZ002- 008-009. RI...None. MARINE...Gale Warning until 7 PM EST Thursday for ANZ231>235-237-251. Gale Warning until 4 PM EST Thursday for ANZ230. Small Craft Advisory until 10 PM EST Thursday for ANZ236. Gale Warning until 10 PM EST Thursday for ANZ250-254>256. && $$ SYNOPSIS...KJC/Doody NEAR TERM...Doody/BW SHORT TERM...KJC LONG TERM...Frank AVIATION...KJC/Frank MARINE...KJC/Frank CLIMATE...
Area Forecast Discussion...CORRECTED
National Weather Service Charleston SC
1030 PM EST Wed Nov 21 2018 .SYNOPSIS... High pressure will prevail through Friday, then a low pressure system will move through on Saturday. A cold front will move through Sunday night followed by high pressure into the middle of next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Temperatures continue to fall quicker than expected within a decoupled boundary layer and nearly ideal radiational conditions in place. Several observations sites across the interior are already in the upper 30s per 22/03z observations and the latest RAP and H3R are both trending cooler with overnight lows. The latest data support lows bottoming out in the mid 30s in the Millen-Allendale corridor. While some recoupling of the boundary layer is likely prior to daybreak as the pressure gradient begins to tighten, it appears there will not be enough wind to preclude scattered frost formation across parts of Jenkins, Screven and Allendale Counties. In fact, some data show a few spots briefly dropping to the freezing mark right at sunrise. A Frost Advisory will be issued from 4-8 AM for Jenkins, Screven and Allendale Counties. Some scattered frost could reach into extreme northern Hampton and northwest Colleton Counties, as well as areas north of Lake Moultrie in Berkeley County, but the impacts areas will remain fairly limited; not enough for an advisory. Elsewhere across the far interior, patchy frost will be possible in mainly sheltered areas. Updated lows range from the mid 30s for areas near the CSRA to the upper 40s along the beaches. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... Cool high pressure will prevail on Thursday while an upper shortwave digs across the central Gulf Coast states. A coastal trough will slowly develop off our coast Thursday night through Friday, with moist isentropic ascent spreading clouds and scattered showers into the area from the southeast. The best rain chances will be along the coast. A stronger upper trough will move into the mid-Mississippi Valley Friday night, allowing a surface low to develop and move from southern GA to a position off the SC/GA coast by daybreak Saturday. Fairly widespread rain showers are expected across the area Friday night into Saturday morning, quickly abating from southwest to northeast during the day as the low pulls out of the area. Highs will be below normal Thursday and Friday with readings in the mid 50s north to lower 60s south. A warm front will lift north midday Saturday, allowing for a substantial rise in temps with highs reaching the low to mid 70s. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... While a fair bit of uncertainty continues, some improvement in conditions is looking possible Sunday as the low pulls away from the area with a drier atmospheric column filling back in over the region temporarily. An upstream phase-locked low pressure system will then transit northeast near the Great Lakes region, pulling Gulf moisture well inland and supporting an additional period of elevated POPs Sunday night into Monday as a cold front crosses the forecast area. Drier high pressure is then expected to persist into mid-next-week. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... VFR. Extended Aviation Outlook: Flight restrictions become increasingly likely Friday through Saturday as low pressure impacts the area. Otherwise VFR conditions expected. && .MARINE... Tonight: High pressure will build in from the Great Lakes region which will help turn the low level flow from northerly to more northeasterly overnight. As the high builds in, the pressure gradient will tighten considerably, resulting in increasing wind speeds. Winds this evening will start off in the 10-15 knot range, becoming at least 15-20 knots by sunrise Thursday. In fact, winds will strengthen sufficiently across the Charleston County waters and the outer Georgia waters to raise Small Craft Advisories by 10z. The advisories will then expand to other zones beyond that. Seas will increase, becoming 2-4 ft out to 20 nm and 4-5 ft beyond by daybreak Thursday. A tight northeast gradient will exist Thursday through Friday evening due to strengthening high pressure inland and a coastal trough offshore. Solid Small Craft Advisory conditions anticipated during this period outside Charleston Harbor. Thus we`ve issued Small Craft Advisory headlines for these areas. 25 kt gusts look like a pretty good bet Thursday night into Friday in Charleston Harbor but we held off on a headline for that zone at this time. Seas will gradually subside over the nearshore waters from late Saturday into Sunday but another round of advisories is possible late Sunday into Monday behind another cold front. && .TIDES/COASTAL FLOODING... Strong northeast winds Wednesday night through Friday combined with increasing astronomical effects will likely result in minor to moderate coastal flooding with the morning high tides Thursday through Saturday. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...Frost Advisory from 4 AM to 8 AM EST Thursday for GAZ087-088. SC...Frost Advisory from 4 AM to 8 AM EST Thursday for SCZ040. MARINE...Small Craft Advisory from 7 AM Thursday to 11 PM EST Saturday for AMZ352. Small Craft Advisory from 5 AM Thursday to 5 AM EST Sunday for AMZ350. Small Craft Advisory from 7 AM Thursday to 5 PM EST Saturday for AMZ354. Small Craft Advisory from 5 AM Thursday to 6 PM EST Monday for AMZ374. && $$
Area Forecast Discussion
National Weather Service Lincoln IL
859 PM CST Wed Nov 21 2018 .UPDATE... Issued at 859 PM CST Wed Nov 21 2018 Current forecast looks to be on track with clear skies and westerly winds expected to continue overnight. Only change made was to lower temps in northwest...around Galesburg by 1 deg. So most areas will see no change in forecast, but will send out update shortly. && .SHORT TERM...(This evening through Thanksgiving Day) ISSUED AT 309 PM CST Wed Nov 21 2018 The cold front will push just south of our forecast area by early this evening, then stall there before shifting north as a warm front on Thanksgiving day. Clouds into early evening will be limited to our far NE counties, roughly from Lacon to El Paso to Danville. HRRR indicates the clouds will generally linger across the north into the overnight, with some dissipation on the southern fringes at times. The overall affect on low temps in our area should be minimal, with upper 20s to around 30 in central/southeast IL. As high surface pressure pulls farther away to the east tomorrow, winds will become southerly and increase to 10-15 mph by afternoon. Periodic clouds will be lingering in the north Thanksgiving morning, then should shift north of the forecast area during the afternoon as the warm front moves into northern IL. With increasing sunshine during the day, we expect high temps to climb toward seasonal normals on Thanksgiving, with upper 40s north and low to mid 50s south. .LONG TERM...(Thursday night through Wednesday) ISSUED AT 309 PM CST Wed Nov 21 2018 Clear skies will continue Thursday night, but steady south winds will result in low temps remaining above freezing in most areas, except for possibly near Danville. A longwave upper trough will amplify across the Plains on Friday, resulting in increased moisture transport ahead of a deepening surface wave. Time height cross-sections indicate we should saturate through a deep enough layer of the atmosphere for rain to overspread central IL quickly Friday afternoon, with widespread rains in our entire forecast area by mid-evening. The models have continued to handle this system consistently, with primarily an open wave even at the surface until Saturday over the Great Lakes, when our precipitation will be done. QPF amounts from Friday afternoon and Friday night still look to remain in the 0.25" to 0.40" range. The increasing rain chances and cloud cover will limit high temperature potential on Friday, as highs top out in the upper 40s north and lower 50s S of I-70. By sunrise on Saturday, the rain should be limited to along the Indiana border for a couple hours, mainly east of Champaign to Lawrenceville. Cloud cover looks to break up from southwest to northeast Saturday afternoon, with areas northwest of Peoria possibly remaining cloudy all day. Despite limited sunshine, central IL will remain under the influence of a warm air mass, as high temps reach the 50s across the board. For the late weekend travel, a low pressure system is still expected to track across Illinois. The 12Z GFS did a dramatic shift southward with the track of that low, on the order of 250-300 miles, bringing colder air and accumulating snowfall into our northwest counties as early as late Sunday morning, with snow continuing into early evening. Several inches of snow could accumulate during a busy travel day. The GFS still indicates primarily rain in the eastern half of our counties, but a significant travel impact could occur if the GFS solution verifies. The overall consensus of other models continue to lean toward our current forecast, with light snow mainly Sunday night for areas mainly west of I-55. The 12z ECMWF and Canadian both continue to show much lower potential for significant snow accum in our area in the Sunday into Monday time frame, with QPF amounts after rain changes to snow supporting mainly a half inch or less in our NW counties. The Canadian sends a secondary wave into IL from the NW on Monday, and triggers some additional light snowfall through the day. The end result in our official forecast was for only minor adjustments on snowfall amounts Sunday night, with little to no snow during the day Sunday. The band of heavy snow from this event (4"-7") still appears to affect mainly Iowa into SW Wisconsin on Sunday-Sun eve, with rain changing to snow into our western counties Sunday night as isentropic downglide dominates in the wake of the surface low. This system will need to be watched closely, as the ECMWF and Canadian surface low tracks did also show a slight southward shift, but not nearly as major of a change in the southward surge of cold air into Illinois on Sunday, when the bulk of our 0.25"-0.40" QPF (mainly rain) falls. A significant push of colder air under Canadian high pressure will dominate the late extended forecast, as high temps on Monday will settle out around 14 to 18 degrees colder than Sunday, with low 30s toward Galesburg, and near 40 toward Lawrenceville. The cold air will remain in place Tuesday and Wednesday, when high temps remain in the 30s across central and southeast IL. After light snowfall or flurries end Monday night, dry weather will occur Tuesday and Wednesday. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 548 PM CST Wed Nov 21 2018 VFR conditions should prevail at all TAF sites next 24hrs. There are some lower clouds just north and northeast of PIA/BMI/CMI but based on satellite loops and HiRes model trends, looks like these lower clouds will remain away from the TAF sites this evening. There is also some high clouds on satellite as well, but these appear thin and wispy so will not mention. So looking at clear skies for SPI and DEC through the period. have done the same for PIA/BMI/CMI but some high thin clouds are possible this evening, but will be clear overnight and tomorrow. Winds will be easterly this evening and then become southeasterly tomorrow morning at around 10kts. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Auten SHORT TERM...Shimon LONG TERM...Shimon AVIATION...Auten
National Weather Service New Orleans LA
359 PM CST Wed Nov 21 2018 .SHORT TERM... Fairly quiet and tranquil conditions are in currently in place attm as the area is under a transition period following exiting trough. Clear skies will prevail through the rest of the day but that will be coming to an end shortly after sunset. A weak open trough is quickly moving east across Texas towards Louisisna. Showers associated with this wave are just now entering extreme SW Louisiana. The HRRR initialized decently and suggests that the leading edge of rain will be reaching western portions of the CWA by around midnight. This early arrival will limit cooling, so have increased overnight lows by a few degrees from the previous forecast. In addition, made some small adjustments in POPS based on trends of the HRRR. This equated to bringing chance POPs as far north of Baton Rouge latitude overnight. These showers will quickly shift offshore as the trough pushes into and across the northern Gulf of Mexico. The area should therefore be rainfree by 18z Thursday. .LONG TERM... Following relatively quick on the heels of the mid week system will be a stronger upper level trough. It will be moving quite fast, tracking from the western side of the Rockies to the lower Mississippi Valley in 24 hours. Maintained previous forecast POPs of 80% for Friday afternoon and night as confidence remains high on timing and coverage. One question is the probability of severe weather. The GFS and ECMWF have completely swapped from 24 hours ago. Now, the ECMWF shows a weak surface low passing along the coastal waters. On the other side, the GFS shows a weak but closed low tracking along the I-10 corridor. Model soundings don`t show much surface based potential as the marine layer looks to be in place and causing an inversion to be in place. This would negate any significant potential impact from high shear that`ll be in place. Best guess attm is that there may be some decently strong storms in the coastal waters and just general thunderstorms elsewhere. Zonal flow will follow the late week trough which will promote warming across the region. It appears this will still be shy of climatological normals, but not by much. Models show that the progressive pattern will continue into the weekend with another even stronger trough swing across the country Sunday. This feature will send a cold front through the CWA Sunday afternoon, bringing with it mostly showers. Return flow will be limited, which will be the biggest hindrance of coverage. In fact, the operational GFS now shows no QPF over the entire CWA Sunday. With just one run of this solution, didn`t completely remove POPs but did lower them some from previous forecast. MEFFER && .AVIATION... VFR conditions are expected to continue through Thursday afternoon or 00z Friday. High and mid clouds will increase across the south half of our forecast area affecting KHUM, KNEW, KMSY, KNBG and possibly KGPT. Some light rain is possible between 06z and 12z Thursday for these sites but visibility restrictions are anticipated. 18 .MARINE... A developing weak low pressure is expected to deepen over the SWRN Gulf and maintain a moderate offshore flow through Thursday morning. Winds will remain out of the NE through Thanksgiving Day but should quickly veer around to onshore flow overnight Thursday as a sfc low approaches the region Friday. Moderate onshore winds will be in place by Friday morning and could become strong approaching 15-20 kts by afternoon. The low will quickly move through the area Friday evening and shortly after midnight winds will already be back out of the west or NW. SCS headlines at the least are likely Friday and Friday night. Offshore winds will be very short lived as a much stronger sfc low develops over the Plains Saturday and Saturday night. Going into Sunday, return flow with winds out of the S-SSW of course will be rather short lived as this system will quickly usher in a strong cold front Sunday afternoon. Look for strong offshore winds behind the cold front with SCY conditions likely over all Marine Zones Sunday night through Monday morning. .DECISION SUPPORT... DSS code: Green. Deployed: None. Activation: None. Activities: River flood warnings at Bogalusa, Pearl River and Red River Landing && .PRELIMINARY POINT TEMPS/POPS... MCB 39 62 43 63 / 10 10 10 80 BTR 41 63 46 66 / 30 10 10 80 ASD 43 63 45 70 / 30 10 10 80 MSY 47 62 51 71 / 30 20 10 80 GPT 44 63 47 67 / 30 10 10 70 PQL 39 63 43 69 / 20 10 10 80 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$
Area Forecast Discussion
National Weather Service Lubbock TX
521 PM CST Wed Nov 21 2018 .AVIATION... A low cloud deck has spread north from the eastern Permian Basin into the southern South Plains. Ceilings appear near 3000 feet above ground level, from the few ceilometer observations we have to our immediate south. So, some uncertainty what elevation this deck will be when it arrives at KLBB shortly before 01Z based on present movement. Solutions not in best agreement on this layer, but chose a blend of the latest RAP and WRF/NAM spreading this at least through KLBB before veering to the east. Will be watching trends, of course, because this cloud layer does have potential to spread eventually towards KPVW and even KCDS later tonight and could easilly drop ceilings into the MVFR range as well. The cloud layer should veer further east and away from the area early on Thursday. VFR conditions expected otherwise with light southerly flow dominating. RMcQueen && .PREV DISCUSSION... /issued 230 PM CST Wed Nov 21 2018/ DISCUSSION... Quiet and progressive weather pattern looks to continue for the foreseeable future. We will begin with shortwave ridging on Thanksgiving day. A milder start to the day with afternoon temperatures warming in the upper 50s to near 60. Increasing SW flow aloft will result in a slight increase in winds late in the day. Fairly tight upper trough will swing southeastward out of the northern Rockies across the Central Plains with attendant surface low deepening over SE Colorado into SW Kansas. The trailing trough associated with this disturbance will move across the area Friday morning. With deep dry air in place, the pressure gradient will kick up winds but very little cooling anticipated. Zonal flow resumes Saturday with gradually increasing surface winds during the day. This next system is progged to move a little farther north (than previous runs) by the models. This will result in an increase in winds late Saturday through Sunday morning with some cooling this time. Mild ahead of this system Saturday in the 60s to mid 70s. This front Saturday night will knock back temperatures around 15-20 degrees for highs on Sunday when compared to Saturday`s levels. Still not much of an opportunity for return low level moisture flow with any of these systems, and not a subtropical tap either. NW Flow aloft with periodic very weak fronts/wind shifts next week. The upper pattern becomes more zonal by the middle of next week with above normal temperatures returning along with continued dry weather. James && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 99/99/05
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
544 PM CST Wed Nov 21 2018 .SHORT TERM...(This evening through Thursday) Issued at 215 PM CST Wed Nov 21 2018 Short term concern remains cloud trends into Thursday and any freezing drizzle threat. Satellite trends show some drying trying to take place over central MN in the wake of some mid level forcing/some mid level FGEN along the anticyclonic side of the retreating upper jet moving through the Great Lakes. Breaks is the cloud cover developed and this should gradually fill back in from the southwest into the evening. Still seeing some radar returns over west central WI this afternoon, but still believe this should end through about 00Z. Radar was active much of the day but still hasn`t been able to saturate the boundary layer. Will continue to carry scattered flurries this afternoon. Temperatures may drop off a few degrees, especially to the east overnight. They may drop off a bit into the evening west before becoming steady or slowly rise late. Moist lower layer remains rather shallow and not really seeing a good indication of drizzle developing. May see that farther to the southwest overnight as overall visibility drops off with some mist possible. Will carry some patchy fog to the west and south later tonight into Thursday morning for now. Clouds should remain to the the northeast CWA as a surface warm front which is progged to move into southwest MN late in the day. We expect this to hold temperatures down over the eastern areas. Still warmer than the last several days. Some mid 40s look likely if the sky clears to the lee of the Buffalo Ridge over the southwest. .LONG TERM...(Thursday night through Wednesday) Issued at 315 PM CST Wed Nov 21 2018 A series of storm systems will move into the western CONUS over the next several days. The northwest flow pattern will become more west, and southwest by Friday, and led to much warmer air advecting northward into the Upper Midwest. Thus, the precipitation type for Friday will be mainly liquid or in the form of rain, or possibly freezing drizzle during the onset Friday morning. The depth of the warm air aloft is large and will lead to this type of precipitation. Not until late Friday evening, or early Saturday morning will temperatures aloft, and near the surface, will be cold enough to support snow. However, by Friday evening, most of the deep moisture will have left the region. Therefore, any snow on the back side of this system will be minimal. As said before, there will be a series of storm systems moving into the western CONUS as the upper ridge breaks down. There still remains a split flow pattern regime through this weekend with a more predominately favored southern jet vs. the northern. Models don`t do well in a split flow regime and this is the case for Sunday`s system moving out into the Plains. Over the past several runs of the GFS, CMC, EC and the Parallel GFS or Fv3, models have supported a more southern track of the surface low. This looks to be related to the split flow regime, and models supporting more energy with the southern jet vs. the northern. It still remains unclear where the bulk and heaviest snowfall path will take, but consistency in a more southerly track means less of a chance of impactful snowfall in Minnesota. Past this weekend, there remains a strong signal of a powerful jet aiming toward the west coast. With a large storm system expected to form in the Gulf of Alaska, the on-slot of Pacific storm systems look reasonable through the extended period. For the Upper Midwest, our weather will likely be controlled by the strength of the negatively supported NAO. Although teleconnections support a more positive PNA next week, the combination of the two interaction leads to a colder pattern. A positive PNA acts to shift Canadian air masses south over the central U.S. This +PNA in conjunction with a negative NAO also supports a semi-persistent Great Lakes/Hudson Bay upper low. This pattern also support a more drier scenario vs. a wetter due to the drier Canadian air masses. Overall, the best chance of precipitation will occur on Friday, with Sunday`s system most likely southeast of Minnesota. Next week remains questionable on precipitation chances, but still on the colder side vs. a warmer scenario. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 544 PM CST Wed Nov 21 2018 As winds become more southeast overnight, bank of stratus will lift northeast and eventually encompass all MPX terminals Thursday by mid Thursday morning, with minimal timing changes to the going TAFs. Expect cigs to drop to IFR levels from at least AXN to MKT on west, with LIFR likely as well. As cigs drop, vis will drop as well, so started introducing some vsby restrictions in BR, though the HRRR shows widespread dense fog developing west of STC and MKT, which is plausible and will have to be watched closely at AXN/RWF. Think the LAV is way to optimistic in clearing the stratus out Thursday and think it will remain in place as the HREF shows, so continued to keep the stratus in place once it arrives. KMSP...Eastern edge of MVFR cigs to the west have not moved much in the last couple of hours, so the 4z onset may be quick, but expect them in place by 7z. After that, its hard seeing a return to VFR conditions anytime soon as low level moisture increases over a frozen ground through Friday. /OUTLOOK FOR KMSP/ Fri...MVFR/IFR with -RA. Wind S at 10-15G20 kts. Sat...VFR with MVFR possible. Wind NW at 10 kts. Sun... MVFR/IFR. Wind NNE 10G20 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ SHORT TERM...DWE LONG TERM...JLT AVIATION...MPG
Area Forecast Discussion
National Weather Service Marquette MI
658 PM EST Wed Nov 21 2018 .SHORT TERM...(This evening through Thursday) Issued at 330 PM EST WED NOV 21 2018 Water vapor imagery and RAP analysis show a strong ridge over the Rockies with a deep downstream trof over eastern Canada into the ne CONUS. Following shortwave passage last evening, a very cold air mass has spread over the area. Current 850mb temps range from around -17C w to -22C e. As a result, current sfc temps are more typical of mid winter, only in the low-mid teens across much of the w and n. The s central has risen into the lower 20s, aided by some sunshine. Obviously, with the arctic air, LES is ongoing off Lake Superior under low-level northerly flow. Winds have been gradually veering thru the day as arctic high pres over northern Ontario is building closer. As a result, dominant LES band that developed last night as expected shifted from western Alger County early this morning into Marquette County, but it never shifted any farther w than the far eastern part of the county, generally staying e of a Marquette to Gwinn line before falling apart. With snowfall rates likely in the 1- 2 inch per hour range, would not be surprised if morning snowfall totals were in the 8-12 inch range in the Skandia/Carlshend area given the persistence of the band. Tonight...arctic high pres will drop se with the center passing just n and e of Lake Superior. Resulting veering/diminishing winds will cause lingering LES to become confined closer and closer to Lake Superior before shifting offshore with onset of offshore wind direction. Based on the rapid diminishing of LES over the last 2 hrs, any additional accumulations should be less than an inch. Late tonight, development of shallow se winds off Lake MI should bring some light LES/flurries into Menominee/Delta/Schoolcraft counties. With close approach of high pres, winds will essentially drop off to calm this evening before light southeasterly winds develop from w to e during the night. This will set the stage for a challenging temp fcst given the potential for some locations to break out of lake stratocu before mid clouds thicken up under advancing waa/isentropic ascent from the w. Given the cold day, shouldn`t be difficult to fall toward 0F in the interior cold spots, but if any locations have little cloud cover for a few hrs, temps could plummet closer to -10F. Best chc for that to happen would be over the eastern fcst area as veering winds cut off lake stratocu this evening, allowing a potentially longer window before mid clouds increase. On Thu, band of mid-level, moist isentropic ascent shifts e, resulting in drying of the mid-levels from w to e. Meanwhile, low- level, moist isentropic ascent continues, aided by moisture off Lake MI under shallow sse flow. During the morning, expect some expansion of light LES/flurries off Lake MI into central Upper MI. Then, as waa raises temps in the moist layer above -10C over the central fcst area, any ongoing flurries/-shsn should change to patchy -fzdz. Expect high temps mainly the 20s. A few spots will reach 30F in the downslope areas w and also near Lake MI. Will be on the breezy side .LONG TERM...(Thursday night through Wednesday) Issued at 301 PM EST WED NOV 21 2018 The upper level pattern will remain progressive through this weekend. After brief upper ridging through Friday morning, a trough will bring mostly rain to Upper Michigan late Friday through much of Saturday. Lake effect/enhanced snows return Sunday through the middle of next week. Thursday evening into Friday morning, southeasterly surface flow will gradually become due southerly, continuing the trend of WAA. Some additional moisture will ride along with the 850 mb southwesterlies, and with a bit of a kink in the low to mid level isoheights as well as indications of some slight isentropic upglide, should be enough lift for scattered fzdz with perhaps a light glaze across portions of the central and eastern UP. Combined with gusty winds, could make for slippery roadways for folks heading out early on Black Friday. During the day, most locations will dry out as upper ridging pushes east and troughing takes on a bit of a negative tilt as it exits the Plains. Should see daytime highs into the lower 40s at most locations. The leading edge of some rain showers will begin to move into the west during the evening. Depending on how late in the day Friday the above freezing temperatures take hold, may have to watch for a non-traditional freezing rain setup early on if roadways remain below freezing for a time during the evening. Scattered rain showers will continue through Saturday morning, with the heavier showers over the south central and east late Friday night and Saturday morning. Rain will mix with and change to snow at times for the interior west with perhaps up to a half inch of accumulation near the WI border. Higher dew points on Saturday combined with the light rain will allow for some minor snow melt, and with winds becoming light, patchy afternoon and evening fog is likely across portions of the region. As the shortwave moves out in the evening Saturday, NW flow will begin to lower 850 mb temps back to near -10C by Sunday morning, which will help ramp up the lake effect once again. Some model discrepancy at this point and a lot will depend upon the track of the stronger low pressure moving across IL on Sunday evening, but some secondary shortwave energy may enhance snowfall for the NW to N wind lake effect belts. Periods of lake effect look to continue through Wednesday, with the details to be hashed out over the coming days. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 628 PM EST WED NOV 21 2018 The lake-effect snow that impacted the terminals is finally winding down this evening. However, cloud deck teetering close to or within the MVFR category is anticipated to persist through much of the TAF period, despite surface high pressure making a quick pass through the Upper Great Lakes region. By later Thursday, surface southerly flow returns, allowing for a fetch to occur off of Lake Michigan. Indications are pointing toward lake-effect showers likely returning for portions of Upper Michigan, potentially impacting KSAW. Should enough warmer air move into the region, precipitation could fall as something other than snow, but confidence is too low for this issuance to mention any other precip type. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 330 PM EST WED NOV 21 2018 Expect a period of light winds, mostly under 15kt this evening, as arctic high pres moves close to Lake Superior. As the high shifts e later tonight, s to se winds will begin to increase from w to e, but more so on Thu. Expect winds to reach 20-30kt Thu and continue thru Fri. Over the e half of the lake, gale force gusts will probably occur at times. Winds will then diminish to under 20kt on Sat as a low pres trof arrives. As the trof departs, winds will increase again on Sun into Mon out of the n to nw, probably into the 20-30kt range. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...KCW AVIATION...lg MARINE...Rolfson
Area Forecast Discussion
National Weather Service San Francisco Bay Area
357 PM PST Wed Nov 21 2018 .SYNOPSIS...An approaching weather system will bring widespread moderate to locally heavy rain and gusty winds to the region through the day, with scattered showers continuing through tonight and into Thanksgiving morning. A second system is expected to bring additional rainfall to the area from Thursday evening through Friday. Dry weather is expected over the weekend before another chance of rain returns by the middle part of next week. && of 02:05 PM PST Wednesday...Upper level trough moving ashore bringing substantial rainfall and breezy to gusty winds with it. Rainfall amounts so far have varied considerably across the area as individual bands of rain have favored coastal regions. The Santa Cruz Mountains have received the most thus far with well over an inch in several locations and over 2 inches on Ben Lomond Mountain. The San Francisco Peninsula and points north have also received substantial rainfall with 0.5 to 1 inch in most locations. A frontal band is moving through the SF Bay and will bring rainfall to most locations, including the East/South Bay and points south and east which haven`t received as much rainfall so far. Convection within the cold upper low is occuring offshore as evident by satellite, and showers will continue in the post frontal environment across the region this evening and overnight. Isolated thunderstorms could form in the unstable environment as well. An area of concern that could see high precipitation totals over the next couple hours is the Big Sur coast and Santa Lucia Mountains, where the HRRR and local WRF are showing the potential for an additional 1-2+ inches of rainfall through this evening. Showers will taper off overnight and most areas will see a break in precipitation Thanksgiving morning. The next trough will bring a return to rain by Thursday afternoon across the North Bay as warm advection, high precipitable water, and strong onshore flow act to create significant precipitation. Models have come into better agreement about the band of rainfall sagging southward into the Bay Area Thursday evening. Rainfall with this system will make it as far south as the Monterey Bay on Friday, but amounts will be much less than the North Bay as the heaviest rainfall will stay focused on our northern zones. Rainfall with this system will bring an additional 2-3 inches in the North Bay Mountains with 0.5 to 1.5 inches in the North Bay Valleys. The Bay Area will see rainfall amounts around 0.25 to 0.75 inches, with lesser amounts points south. Expect a return to quiet weather this weekend as rain showers taper off on Friday night. A shortwave ridge will build across the eastern Pacific Saturday through Monday with a weak shortwave trying to move through on Sunday. However, this is not expected to bring any precipitation at this time. A return to wet weather is likely the middle by the Tuesday into Wednesday timeline as both the GFS and Euro are in agreement about another trough forming in the East Pacific. && .AVIATION...As of 3:47 PM PST Wednesday...Complex forecast, especially the details, in the short term as a frontal boundary sweeps through the Bay Area bringing rain and lowered cigs. The bulk of the precip has pushed through most terminals, but a transition to scattered showers and eventually vcsh overnight. Latest short term models do bring another pulse of showers late tonight into tomorrow morning. Some clearing is possible tomorrow afternoon before another storm system moves in from the north. Overall conf - medium Vicinity of KSFO...MVFR conditions as rain slowly moves eastward. Winds are cooperating at the moment. Poss VFR conditions tomorrow before more precip returns toward the end of the taf. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...MVFR for MRY with rain, but SNS is still being rain shadowed with VFR conditions. Improving conditions overnight. && of 03:39 PM PST Wednesday...A storm system is moving through the coastal waters this afternoon. As a result, winds will likely remain southerly and gusty ahead of the surface front with lighter westerly post frontal winds. A possibility of thunderstorms exists across the waters through this evening and possibly into tonight. A second storm system will bring another round of gusty southerly winds to the northern waters between Thursday and Friday afternoons. Gale force gusts are also forecast for the Northern San Francisco Bay on Friday. Mixed swell, predominately moderate northwest with a light southerly component. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Pigeon Pt to Pt Pinos 0-10 nm until 9 PM SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 9 PM && $$ PUBLIC FORECAST: ST AVIATION: MM MARINE: DRP Visit us at Follow us on Facebook, Twitter, and YouTube at: