Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/04/17

Area Forecast Discussion
National Weather Service Buffalo NY
903 PM EST Tue Jan 3 2017 .SYNOPSIS... A mild airmass with widespread rain will continue into the overnight hours across the region before a cold front sweeps across the Eastern Great Lakes...ending the rainfall and ushering in much colder air. Westerly winds will become strong tomorrow, and lake effect snow will become organized tomorrow afternoon east of the lakes, with such snowbands oscillating east of the lakes into the start of the weekend. Air temperatures will remain below normal later Wednesday and through the weekend. && .NEAR TERM /THROUGH WEDNESDAY/... Surface analysis shows a broad surface low crossing Western NY late this evening. This low will consolidate and deepen overnight as it moves north into Southern Ontario and reaches western Quebec by Wednesday morning. Regional radars showing the back edge of steady rain moving through the Finger Lakes and eastern end of Lake Ontario at mid evening, with the steady rain continuing for several more hours east of Lake Ontario before tapering off overnight. Farther west, another area of rain showers will persist across Western NY through late evening. Upstream radars also show yet another area of rain in NE Ohio, which the latest high res HRRR guidance brings into Western NY overnight. Later tonight behind the cold front temperatures both at the surface and aloft will drop allowing trailing showers along and behind the cold front to possibly end as some wet snow across the higher terrain of the western Southern Tier. Lake effect snow will begin in earnest through the day Wednesday as temperatures at 850 hPa drop from around 0C to start the day down to the negative teens Celsius by the close of Wednesday. For Lake Erie...initially early Wednesday morning there may be some lake convergent precipitation...with a mixture of rain/snow and possibly some sleet through the morning hours...this before the main dry slot in the lower level arrives. Overall precipitation will be around a tenth of an inch or lower. This precipitation will diminish some through the morning as drier air briefly passes across the lake. Synoptic moisture will soon wrap back around the lake, and with falling snow dendritic growth zone, we should see a band of lake effect snow form on a WSW wind through the late morning and afternoon hours. The westerly wind flow over the shorter fetch of Lake Erie, combined with a strong wind flow that will limit the residence time over the lake should limit snow accumulation through the late Wednesday afternoon hours to just a few inches across Ski Country, as well as some of the southern southtowns of Buffalo. For Lake Ontario...temperatures will fall through the day at 850 hPa, steepening the low level lapse rates, and with the dry slot behind the cold front not likely to reach the lake, we should see a band of snow develop through the morning hours, oriented along the long axis of the lake and towards the Tug Hill region. There is model indication that an upstream connection to the upper lakes will occur, adding moisture to the lake band and increasing the snowfall rate. Here, a better organized band of snow is expected than off Lake Erie, and snowfall amounts of 3 to 5 inches are possible by late in the day Wednesday across the Tug Hill region. In addition to the lake snows, there will also be a strong wind across the region. The surface low this afternoon over the Great Lakes region will deepen to around 980 mb by Wednesday evening over southwestern Quebec. This will be around 3SD below normal. While the surface low will track over the region tonight, with little winds, the combination of the tightening pressure gradient from the deepening surface low to our north and building high pressure over the Plains and Ohio Valley, the steady cold air advection, and moderate isallobaric couplet passing over the region will all combine to produce gusty westerly winds across the entire Eastern Great Lakes region tomorrow. Strongest winds will be across the lake plains and east of Lake Ontario where gusts over 50 mph will be possible. The position of the 40 to 45 knot low level jet, just a thousand or so feet above the ground, coupled with the cold air advection and deepening surface low may allow for wind gusts 45 to 50 mph over the higher hills of the region. We will also have watch the lake seiche that will develop with the strong southwesterly flow. Current thinking is that the rise in the lake on the eastern end will be around 4 to 5 feet...or just below advisory level. The gusty winds and falling snow will bring areas of blowing snow with reduced visibilities, first east of Lake Ontario where lake snows will likely accumulate a few inches first, and then east of Lake Erie tomorrow evening. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... ...Significant Lake Effect Snows... Arctic air will continue to pour across the lower Great Lakes through the period as a deep trough gets carved out across the Great Lakes region. Steady cold air advection with 850 mb temperatures starting Wednesday evening around -15C falling to around -18C by Friday morning. This will ramp up the over-lake instability with lake induced CAPES up to 600 J/kg. Model soundings showing lake induced equilibrium levels near 15K feet off Lake Ontario and near 10K feet off Lake Erie. The 260-270 degree flow will focus the heaviest lake snows south of Buffalo across the Chautauqua Ridge and the Tug Hill respectively Wednesday night into Thursday morning. A passing short wave will then back the flow slightly potentially shifts heavy bands northwards into the Buffalo and Watertown areas, respectively. Bands are expected to shift south once again Thursday night into Friday as another short wave passes over the area. With a long fetch down Lake Ontario and closer proximity to wrap- around synoptic moisture, the Tug Hill should have no problem accumulating at least 1-2 feet Wednesday night through Friday, therefore the Lake Effect Snow Watch has been upgraded to a Lake Effect Snow Warning. Areas east of Lake Erie should easily see several inches of snow, including the Buffalo metro area during Thursday, especially the Southtowns. Lake parameters are not quite as outstanding as off of Lake Ontario, with drier air aloft, lower inversion heights, and the potential movement of the bands across the area leading to lower snow totals. We are likely looking at least 6-12 inches with localized highest amounts focuses just to the south of Buffalo and along the Chautauqua Ridge. Enough confidence attained in newest guidance to upgrade these areas to a lake Effect Snow Warning from Wednesday afternoon through Friday. With the potential for the heavier lake snows to shift a little father north toward the Buffalo metro area, have decided to place northern Erie county into a Lake Effect Snow Advisory for the immediate Buffalo southtowns. Regarding temperatures, the arctic air pouring across the lakes will be reinforced by several additional waves rotating through the longwave trough that is progged to set up over the eastern half of the country. Highs in the 20s Thursday will give way to teens Friday with lows in the teens Wednesday night and Thursday night and potentially in the single digits Friday night. The brisk westerly flow will add to the chilliness, with wind chills falling into the single digits Wednesday night and lasting at least into Friday morning. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Mid-winter cold should be with us through the weekend and early next week, with another potent upper level trough diving out of the Arctic and across the Great Lakes by Saturday. This will also continue lake-effect snows downwind of the lakes through the weekend, though we may see a little more weakening and movement in the bands, particularly as flow veers more northwesterly Sunday in response to strong ridging upstream. At the moment, it appears that we may see a break in the cold by Tuesday, as the general consensus among global models is for a deep upper low to develop over the Gulf of Alaska by Sunday, forcing ridging downstream across the Western U.S. that eventually works its way eastward during the early part of next week, helping to break down the longwave trough over the East and resulting in a more zonal flow aloft, with relatively mild Pacific air flowing eastward across the northern half of the country. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... The first area of steady rain will continue through the midnight hour east of Lake Ontario before tapering off overnight. Another batch of showers across Western NY will continue through late evening and be re-enforced by a third area of rain over NE Ohio. The combination of rain and BR will keep areas of MVFR and IFR VSBY overnight, with widespread IFR CIGS. This rain will all taper off from west to east Wednesday morning with the passage of a cold front. VSBY will improve to VFR, and CIGS will also improve to a mix of MVFR and lower end VFR. Lake effect snow will then form east of the lakes for the last 6 or so hours of the TAF period Wednesday afternoon and evening. Better organization will be east of Lake Ontario where a band of snow may bring IFR or lower flight conditions to KART. A more sheared environment will produce more disorganized snows east of Lake Erie tomorrow morning, but a band of snow will form by late morning as low level moisture increases and a WSW flow brings snows across Ski Country...with possible snows near KBUF and KJHW through 18Z. In addition to the snows...Wednesday will become windy across the TAF region as an area of low pressure deepens considerably over Quebec, and surface high pressure noses towards the Ohio Valley. Westerly gusts up to 40 knots will be possible across all 5 TAF sites. Outlook... Thursday through Friday...Lake effect snow in the snowbelts east of the lakes with MVFR/IFR. Otherwise VFR. Saturday and Sunday...VFR/MVFR with a chance of snow. && .MARINE... A cold front will cross the lake waters tonight...this connected from a deepening area of low pressure that will advance across Lake Ontario and through southern Quebec. The combination of the deepening area of low pressure, strong pressure gradient owing from a building surface high pressure over the Plains and towards the Ohio Valley and steady cold air advection through the day will bring gale force winds on both lakes...starting in the west around 12Z, and then by 15Z points eastward. Expect gales through the evening hours of Wednesday before the departing surface low relaxes the pressure gradient such that winds will drop below gale force late Wednesday night/early Thursday morning. A cold westerly flow through the weekend may kick up waves to low end small craft advisory levels from time to time, but winds will be much less this weekend than with the gales upcoming. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...Wind Advisory from 10 AM Wednesday to 1 AM EST Thursday for NYZ001>004-010>014-019>021-085. Lake Effect Snow Warning from 1 PM Wednesday to 5 PM EST Friday for NYZ012-019-020-085. Wind Advisory from 1 PM Wednesday to 10 AM EST Thursday for NYZ005>008. Lake Effect Snow Warning from 4 PM Wednesday to 5 PM EST Friday for NYZ006>008. Lake Effect Snow Advisory from 1 PM Wednesday to 6 PM EST Thursday for NYZ010. MARINE...Small Craft Advisory from 7 AM Wednesday to 10 AM EST Thursday for LEZ020. Gale Warning from 7 AM Wednesday to 7 AM EST Thursday for LEZ040-041. Small Craft Advisory from 7 AM Wednesday to 10 AM EST Thursday for LOZ030. Gale Warning from 10 AM Wednesday to 10 AM EST Thursday for LOZ042>045-062>065. && $$ SYNOPSIS...THOMAS NEAR TERM...HITCHCOCK/THOMAS SHORT TERM...TMA LONG TERM...TMA/WOOD AVIATION...HITCHCOCK/THOMAS MARINE...THOMAS
Area Forecast Discussion
National Weather Service Green Bay WI
525 PM CST Tue Jan 3 2017 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Wednesday Issued at 238 PM CST Tue Jan 3 2017 The latest rap analysis and satellite/radar imagery show a potent shortwave, located over the boundary waters of Minnesota, pushing an arctic front across central WI early this afternoon. Still some lower visibilities around 1 mile hanging on over the Door Peninsula, but most locations have seen their visibilities improve above 3 miles. Looking upstream, though a narrow break in the clouds is moving across the MN/WI border, there is another large area of overcast conditions over northwest Minnesota where snow showers and flurries are occurring. As arctic air plows across the region tonight, light snow chances, clouds, and temps are the main forecast concerns. Tonight...The arctic front will finish crossing northeast Wisconsin early in the evening. Cold advection will then continue through the night, dropping 850mb temps to -18/-19C, and low temps into the single digits. West winds will ramp up through the night, with some gusts approaching 30 mph. This will drop wind chills over central and north-central WI into the 15-20C below zero range by sunrise. In addition, a potent upper shortwave will amplify across the western Great Lakes, with comma head moisture spreading light snow showers and flurries from northwest to southeast over the course of the night. The most persistent snows should be over north-central WI, where a minor lake contribution will occur over Vilas Co., and also where mid-level moisture looks the most robust. Will show up to an inch of snow there. Little to no accumulations are expected elsewhere. Wednesday...Upper troughing will slowly shift east across the central Great Lakes but cyclonic flow will continue through the column. Some residual moisture will linger in the 900-850mb layer, which combined with steep low level lapse rates, should lead to scattered snow showers and flurries across the area. Minor accumulations under an inch could occur in the snow belts of n-c WI. Highs ranging from the middle single digits above zero to the mid teens near the Lake. Wind chills will approach -20C between 12-15Z over central and north-central WI. .LONG TERM...Wednesday Night Through Tuesday Issued at 238 PM CST Tue Jan 3 2017 Arctic air will remain over the region through the work week, with a reinforcing shot arriving in the wake of another frontal passage on Saturday. Precipitation chances will be minimal, except in Vilas county, where scattered snow showers or flurries will occur from time to time. The main story during this period is much below normal temperatures, with the potential for wind chill advisories west of the Bayshore and Fox Valley areas, where wind chills of -20 to -30 F are possible Wed/Thu/Fri/Sat nights. Arctic high pressure is expected to slide east of the region Sunday night into Monday, with increasing south winds leading to significant warm air advection. Aside from moderating temps, there is a small chance of snow on Monday. Both the GFS and ECMWF show a northern plains low pressure system heading toward western Lake Superior Monday night into Tuesday, with snow possibly mixing with or changing to rain as warmer air arrives on Tuesday. Given the decent agreement in the medium range models, will go with likely pops for day 7, which is usually a risky proposition. && .AVIATION...for 00Z TAF Issuance Issued at 525 PM CST Tue Jan 3 2017 West winds will be on the increase tonight and continue into Wednesday in the wake of an arctic front. MVFR cigs over the region early this evening may depart later evening or overnight as drier air pours in. More MVFR clouds with SW-/SW-- over Minnesota may work into the state from west to east late tonight into Wednesday. This second area of clouds with the upper low system will also be sliding over a drying boundary layer so coverage will turn variable. Mvfr lake effect clouds will be more widespread toward the Lake Superior snow belt region. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......Kieckbusch AVIATION.......TDH
Area Forecast Discussion
National Weather Service Grand Rapids MI
1048 PM EST Tue Jan 3 2017 LATEST UPDATE... Update .SYNOPSIS... Issued at 326 PM EST Tue Jan 3 2017 Light rain and fog will move out of the area by this evening. Colder air will then be spreading across the area later this evening and through the overnight hours. This cold air will then produce lake effect snow showers that are expected to last at least through Friday. Normally favored lake effect areas will see multiple inches of snow through Friday, with inland areas toward Clare and Lansing seeing little to no accumulation. Blowing and drifting snow will cause impacts for areas closer to the lakeshore late tonight Through Wednesday with gusty winds. && .UPDATE... Issued at 1048 PM EST Tue Jan 3 2017 We are seeing several bands of showers (rain and snow) associated with the passage of the arctic front early this evening. This was shown well run after run with both the RAP and HRRR models. I adjusted the hourly pops to show this feature. I will not add much QPF however. There should be break in the snow showers after midnight as we have to wait for the inversion height to get deep enough to start the lake effect snow showers. This could take until 5 to 7 am Wednesday morning. Given the gusty winds and temperatures near 15 (more or less) these snow showers will likely still cause travel issues this coming morning. I believe our headlines are good. I also lowered the hourly temperatures after midnight. Temperatures are falling quickly in Wisconsin. Madison fell 16 degree between 5 pm and 10 pm this evening, from 32 to 16. Most other stations in Wisconsin are seeing similar falls in there temperature. This will cross the lake and reach our CWA after midnight. I used the time delayed ensmebles of the HRRR and RAP models to create the hourly temperatures. We could see temperatures near 10 above in parts of our northern CWA by 7 to 8 am Wednesday morning. This will put wind chills into the 5 to 10 below range by Wednesday morning near Route 10. && .SHORT TERM...(This evening through Thursday night) Issued at 326 PM EST Tue Jan 3 2017 We will be letting go of the Dense Fog Advisory this afternoon, and keeping the Winter Weather Advisory as is for tonight into Thursday. The potential still remains that this may need to be extended at some point, but there is plenty of time to monitor that need. Winds have started to come around to the NW and pick up enough to mix the low levels a bit and help to dissipate the fog as the low exits to the SE. The change of the wind to be from the NW is starting the process for the colder air to move over the area. It seems like KLDM and KMBL are seeing the cold air move in with pcpn starting to change over there. This will continue to spread through the area, and all locations should be over to snow by 06z tonight. We expect lake effect to start kicking in toward midnight when the air is expected to become sufficiently cold enough. Inversion heights will still be quite limited at that time, but will increase to around 5-6k ft after 06z as the upper jet core sinks south through the area. H850 temps will bottom out around -20 to -21C around 18z on Wed producing delta t/s of mid 20s. We are expecting numerous snow showers to be present in the favored WNW areas from tonight, right on through Thu night and beyond with some small fluctuations in the bands. The thought continues to be that amounts will not be too heavy, but accumulations will add up over the prolonged time frame. Limited inversion heights, and the DGZ near or below the cloud base will be conducive for smaller snowflake size and limiting the "fluff factor". Blowing and drifting snow will be an issue with a fresh dry snow falling and wind gusts up to around 35 mph or so late tonight and Wednesday. The most impacted area will be generally west of U.S.- 131, maybe a little further inland along I-94 with the WNW flow. This will become less of an impact Wednesday night and beyond as winds will diminish a bit. .LONG TERM...(Friday through Tuesday) Issued at 326 PM EST Tue Jan 3 2017 Low level troughing persists along the lakeshore Friday into Saturday...with a northwest flow prevailing. That combined with the arctic airmass in place should result in continued lake effect snow showers...most numerous generally along and west of Highway 131. The greatest low level convergence remains situated from South Haven to Muskegon. This is the region that should see the most snow in this period. The models for several runs have been showing a 700 mb wave tracking through Friday am. This feature is forecasted to have relatively deep moisture...up through -30 deg c. If this feature does develop...the snow showers Friday morning could be quite heavy. Low level convergence has the look of an I94 band setting up as this feature tracks through. That would support the heavy snow bands reaching well inland toward Lansing and Jackson. Then Saturday night into Sunday...more of a northerly flow evolves. This should cause the snow showers to migrate closer to the lakeshore. Will feature the highest POPs from Ludington southward through Muskegon and into South Haven. As the airmass will be plenty cold enough for lake effect...and increased risk for a heavier band of snow to develop exists. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 646 PM EST Tue Jan 3 2017 The arctic front is currently over eastern WI based on the surface temperature and dew point gradient. The surface air temperature was in the mid 30s along the lake shore over eastern WI but only in the teens over the western part of the state. There is a band of snow showers developing (mostly aloft now) along this front. I do believe that the HRRR and RAP models depicting that band of snow showers to develop and intensify as is crosses Lake Michigan into lower Michigan between 9 pm and midnight makes sense to me. I put TEMPO 1sm -shsn in most of the tafs to cover this band moving through. After that there will be a break in the snow showers. The actual lake effect event will begin after 10z and will continue through most of the rest of the week actually. On Wednesday, due to the strong winds the heaviest snow will be near US-131 by Thu winds will be lighter and the heaver snow bands will be closer to the lake shore. && .MARINE... Issued at 326 PM EST Tue Jan 3 2017 We have upgraded to a Gale Warning for the event from later this evening through Wednesday evening effective immediately. Model winds have trended up over the past 24 hours for the winds from tonight through Wednesday evening as the cold air pours in over the area. We are looking at gales up to 40 knots likely. Freezing spray will become likely with the cold air, winds, and waves. Winds will diminish some then late Wed evening, but remain in the Small Craft Advisory category through Thursday with the cold air coming over the relatively warmer waters. && .HYDROLOGY... Issued at 112 PM EST Tue Jan 3 2017 Precipitation totals over-performed previous forecasts with a stripe of rainfall generally between 0.50-0.75 of inch, extending from far southwest Lower Michigan to the Saginaw Bay. Localized totals of around 1.00 inch cannot be ruled out when referencing radar estimates and MRMS products. As a result, already saturated ground soil has allowed moisture to quickly make it into streams and rives to lead to fairly steep rises. Fortunately, long range models do not bring any moisture laden systems through over the next 7 days. We will transition to lake effect snow over the next several days, placing much of any additional moisture over extreme western portions of the state. Concerns through Thursday and Friday will be in relation to ice formation, as high temperatures sink near or below 20 degrees and low temperatures consistently bottom out in the single digits and low teens through Sunday. Conditions will need to be closely monitored through the week given high river levels and potential for ice formation. Fortunately, only lead to minor river flooding immediately along river banks and adjacent low lying areas. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Winter Weather Advisory from 4 AM Wednesday to 10 AM EST Thursday for MIZ037>039-043-044-050-056-057-064-065-071>073. LM...Gale Warning until 10 PM EST Wednesday for LMZ844>849. && $$ UPDATE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...MJS AVIATION...WDM HYDROLOGY...JAM MARINE...NJJ
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
936 PM EST Tue Jan 3 2017 .SYNOPSIS... A weak cold front will move off the the Carolina Coast later tonight with colder air gradually spreading back over the region on Wednesday and Thursday. A low pressure system is expected to lift out of the Northern Gulf of Mexico early Saturday and could bring widespread winter precipitation to the region. && .NEAR TERM /THROUGH WEDNESDAY/... As of 9:35 EST Tuesday: Based on local radar trends and latest RAP model data, we have slowed down the precipitation entering the south end of the western North Carolina mountains. We still think a secondary surge of moisture and DPVA will arrive, instigating the shower activity. Thermal structure continues to only support a mix to snow at the highest elevations in the wee hours Wednesday morning. Meanwhile, the cloud and fog forecast was adjusted to better fit going conditions. There remains pockets of low clouds and patchy to areas of fog ( some locally dense ) mainly in parts of the western piedmont and foothills of North Carolina. High clouds may have locked in some of the low clouds, and a few visibility values are running around 1/4 mile. Meanwhile to the south, higher clouds continue, along with some gradient. Nevertheless, with winds on a downward trend tonight ( and thinning upper clouds ) we would now expect some fog to re-develop. We have hit the fog harder in our northeast forecast area, and brought more fog in to the south. As it stands now, the dense fog appears isolated and random from site to site. We have issued an SPS to call attention to the changeable conditions. If the fog fans out, a Dense Fog Advisory may be required. Temperatures tonight seem to be doing okay, and only minor adjustments made in that department. Meanwhile the models favor this pattern persisting into daybreak Wednesday as the flow is reinforced by an intruding cold front. However, this front will advect much drier air into the region yielding the end of any upsloping shra activity by late morning into midday. As caa initiates and the atm cools from the top down, and lingering high elevation precipitation cold change phase to a rain/snow mix, before diminishing altogether. Downsloping flow will dominate the pattern across the low terrain of NE GA and the western Carolinas on Wednesday leading to partly/mostly sunny skies and temperatures nearly 8-10 degrees above normal, yet at or below normal westward atop the mtns thanks to the developing caa. Lastly, winds are expected to increase amidst improved H85 flow yielding strong, yet sub advisory wind gusts across the northern mountains by early/mid morning lasting through periods end. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... At 2 PM Tuesday: On Wednesday night a low amplitude upper trough will be over the Easter USA, with low amplitude ridging to the Western USA. The trough broadens to the west, and progresses slowly across the Eastern USA through Thursday and Friday. Weak channeled vorticity will round the base of the trough the period, but the models disagree on timing and placement. The bulk of more vigorous vorticity will pass well north of our area however. At the surface, on Wednesday night dry high pressure will be over our area, although the models show some high level cloud cover moving over the area. a cold front will approach from the northwest on Thursday, with vertical profiles supporting light snow in the NC Mountains. As the front moves through our area Thursday night, snow chances increase in it`s wake, mainly over the NC Mountains, but perhaps spilling over the Blue Ridge to the Foothills and Piedmont in robust northwest flow. Enough warming is expected during the day to change precipitation over to snow along and east of the Blue Ridge. Temperatures will fall from slightly above normal on Wednesday night, to below normal in cold advection behind the front. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 230 PM EST Tuesday...The main focus this period will be on the possible winter event Friday night and Saturday. Models agree on a system during this timeframe and that there will be some snow, but the details of how much and where are still uncertain. The 12z GFS has the coldest solution with mainly snow but the precipitation is the lightest. The 12z runs of the ECMWF and Canadian models have heavier precipitation but start it off as rain in the Piedmont before transitioning to snow. GFS ensemble runs also run the gamet in amounts due to similar differences. Plan to go with all snow in the mountains with an initial rain/snow mix in the Piedment becoming all snow Friday evening. Right now am thinking accumulations of 1-3 inches but this could change significantly with later forecasts. The storm will quickly depart Saturday afternoon with cold high pressure building in for the weekend into the first half of next week. Expect highs in the 20s and 30s and lows in the teens to around 20 Sunday and Monday. These readings may be a little colder if there is actually snow on the ground. Temperatures will begin to moderate some by Tuesday but conditions are expected to remain dry after Saturday. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... At KCLT and Elsewhere: As noted earlier the slowly retreating wedge boundary continues to lift north into locations north of the airfield. Nevertheless, left over moisture and brief clearing has allowed some stratus to develop in areas around KCLT. If winds should drop off ( and we think they will ), we will probably note a reduction of the stratus layer and the reformation of fog. As a result we have trended the KCLT TAF in that direction, back to IFR in CIGS and VSBYS. Ample drying and subsidence Wednesday should scour any remaining lower clouds or fog out by mid morning, with a trend to VFR. Elsewhere a virtual smorgasbord of clouds and fog issues to the north at Hickory, while AVL was waiting on clouds arriving from the west. Plan to keep HKY down overnight, until we see differently. Our southern TAF sites have cleaned out, to VFR conditions, with the old front lifting north and some gradient. It remains somewhat questionable how much fog will reform, but we have allowed some stratus and fog to return / based on latest guide / in the overnight hours. Therefore back to either IFR or MVFR conditions. Improving conditions then expected Wednesday and low level moisture and sinking air scour any remaining clouds out. Outlook: Drier conditions will persist into Wednesday. Tremendous uncertainty then develops in the forecast for the weekend, with a period of wintry weather possible at some point, most likely Friday night into Saturday. Confidence Table... 02-08Z 08-14Z 14-20Z 20-00Z KCLT Low 54% Med 72% High 100% High 100% KGSP Low 55% Low 57% High 100% High 100% KAVL Med 72% Med 75% High 86% High 100% KHKY Med 66% Med 63% High 97% High 100% KGMU Med 79% High 100% High 100% High 100% KAND Med 66% High 100% High 100% High 100% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables and ensemble forecasts are available at the following link: && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...JPT NEAR TERM...CDG/TS SHORT TERM...JAT LONG TERM...SW AVIATION...CDG/TS
Area Forecast Discussion
National Weather Service Lincoln IL
836 PM CST Tue Jan 3 2017 .UPDATE... Issued at 836 PM CST Tue Jan 3 2017 Much colder and drier air moving into central and southeast Illinois this evening following today`s cold frontal passage. Temperatures this evening as of 8 pm range from 18 degrees in Galesburg to 37 in Lawrenceville with temperatures already in the teens upstream in Iowa poised to push into the area overnight. Strong pressure gradients between the departing low and high pressure over the Plains are resulting in windy conditions with 20 mph NW winds and gusts as high as 35 mph. Back edge to low clouds and stratus is past Springfield to Peoria and should push east to around the Indiana border by Midnight. Expecting lows tonight to reach as low as 10 degrees for areas NW of Peoria ranging to the low 20s south of I-70, with wind chills causing temperatures to feel 10 to 15 degrees colder. Have updated forecasts for earlier clearing and gustier winds this evening, and trended lows slightly colder given th cold temperatures upstream advecting into the area. && .SHORT TERM...(This evening through Wednesday) ISSUED AT 210 PM CST Tue Jan 3 2017 A short wave will exit eastern IL late today as it moves into the Ohio river valley. Rain showers east of the IL river will diminish from west to east during the afternoon and early evening, ending near the Wabash river by mid evening. Stratus deck with bases below 1k ft over IL. These low clouds were decreasing over central and western IA and NW MO, and HRRR models shows these low clouds decrease from nw to se during the evening, diminishing near the Wabash river valley early overnight. An arctic cold front has pushed southeast of the Wabash river by mid afternoon with brisk nw winds 15-25 mph dropping temperatures. Mercury levels currently range from mid 30s nw of the IL river to the upper 40s near Lawrenceville. Low temperatures tonight will range from 10-14F nw of the IL river where wind chills will lower to 0 to 5 below zero later tonight into Wed morning. Lows in the lower 20s from I-70 southeast where wind chills reach 7-12F. 1038 mb arctic high pressure over MT ridges into the MO valley on Wed and should provide a mostly sunny but cold day to central IL. Mid/high clouds will be increasing during mid/late Wed afternoon ahead of next wx system moving into the central plains. 850 mb temps down to minus 10-14C on Wed gives cold highs in the lower 20s northern CWA and upper 20s in southeast IL. Brisk nw winds to continue tonight and Wed keeping wind chills down in the single digits, and even zero to 5 below zero over northern/nw CWA. .LONG TERM...(Wednesday night through Tuesday) ISSUED AT 210 PM CST Tue Jan 3 2017 All models have now come into agreement and showing consistency with previous run, in regards to the weather disturbance forecast to quickly slide across the area Wed night through Thursday morning, with a quick shot of snow. Very cold temps in the Arctic airmass that is currently advecting into the region, will be cold enough that any energy/vort max will produce enough lift for light snow and flurries to be possible as it moves across the region. With airmass cold and dry, snow to liquid ratios will be quite high. So with qpf being small as well, not much snow will fall during the period in the area. Current forecasted track of this piece of energy suggests that most of the accumulating snowfall will be along and south of a Quincy to Paris line. Snowfall amounts of around an inch or more will be possible in west central IL. North of this area, flurries are possible as forcing will be weaker and moisture more limited. But, still wont take much forcing in the cold air to produce flurries. However, for now, will just continue the slight chance of snow in this area. Beyond this mid week system, dry and very cold weather is expected through the rest of the week and through the weekend. The high pressure will not get east of the CWA til the beginning of the week. Once this occurs, warmer temps will advect back northward into the area, along with the chance of precip. This looks to begin by Tuesday, so precip type will mix of rain and snow early and then changing to all rain as temps warm well above freezing. Temps overall this forecast package will be very cold with lows in the single digits and highs in the 20s. Temps will begin to warm starting Monday and then get into the 40s for Tuesday. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 541 PM CST Tue Jan 3 2017 Brisk NW winds behind a recent cold front will continue for the next 24 hours with wind speeds 10-20 kts and typical gusts 20-25 kts. Wind speeds decreasing late in the 24 hour TAF forecast period. Otherwise...IFR/MVFR cigs improving to VFR category by 3-6Z as dry air moves in from the NW. Isolated -DZ/-FZDZ early this evening as precipitation rapidly diminishes from west to east with colder air moving in to drop temperatures below freezing. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...37 SHORT TERM...07 LONG TERM...Auten AVIATION...37
National Weather Service Jackson KY
953 PM EST Tue Jan 3 2017 .UPDATE... Issued at 953 PM EST TUE JAN 3 2017 Temperatures are now starting to fall over our western counties signaling the passage of the cold front. Numerous showers occurring in advance of the front will become more scattered in nature and transition to drizzle overnight and this is handled well in the forecast. No lightning has been observed this evening so that threat was removed from the forecast. UPDATE Issued at 537 PM EST TUE JAN 3 2017 Removed any mention of snow later tonight into Wednesday morning, instead opting to transition showers to areas of drizzle before ending as models indicate clouds shallowing out and remaining too warm for ice to be present. Surface temps should stay above freezing where any drizzle occurs so do not anticipate any issues with freezing drizzle. && .SHORT TERM...(This evening through Wednesday night) Issued at 325 PM EST TUE JAN 3 2017 19z sfc analysis shows low pressure shifting east through the Ohio Valley with a cold front stretched back west southwest into the Southern Plains. This places eastern Kentucky in the system`s warm sector with scattered to numerous showers passing through the CWA under nearly overcast skies. Still looking at a potential for the showers to become more convective and deeper late this afternoon and into the evening - perhaps even to the point of some thunder before the system`s cold front works through later tonight. Currently readings are holding up in the upper 50s and lower 60e with dewpoints just a category behind for most places. The showers and low clouds are still bringing local patches of fog and reduced visibility to parts of the area. Meanwhile, winds have begun to swing more to the west with the sfc low now off to the northeast. The models are in good agreement aloft through the short term portion of the forecast. They all depict the southern stream wave - responsible for our wet weather these past couple of days - pulling off to the east this evening while a northern stream trough pivots into the northern Great Lakes. This northern wave drives height falls and energy deep into the Ohio Valley tonight as fast flow moves through Kentucky. This is well modeled through the day Wednesday even as it lifts northeast into Ontario and Quebec. Behind this, a much broader trough will take shape and start to shift south into the Upper Midwest by Thursday morning with bigger implications for our weather for the latter part of the week. Given the good agreement for the bulk of the short term will go with a blended solution with the HRRR and NAM12 favored in terms of details. Sensible weather will feature scattered to numerous showers into the evening with even a rumble of thunder possible. CAA will kick in late this evening as a cold front crosses eastern Kentucky. This will end the threat of thunder and also bring in brisk conditions with northwest winds of around 10 mph continuing into the early morning hours of Wednesday. The moisture will shift off to the east just as the column cools enough from west to east for a brief transition to snow flurries when the pcpn exits to the east. Of note, will be a return of sunshine on Wednesday as high pressure quickly moves into the area, but temperatures will not rebound much from the morning lows. Later that night, cold air continues to pour into the area with temperatures bottoming out in the lower 20s most places by Thursday morning - this is as the next sfc wave approaches and brings lowering clouds into east Kentucky by morning - with snow not far behind. See below for more details on this cold and snowy blast to end the work week. Per the usual, started with the CONSShort and ShortBlend for most of the wx elements with only minor adjustments in the near term to account for current conditions and then fine tuned lows Wednesday night. Also, beefed up PoPs through the first part of the night and held them in a tad longer in the far southeast for Wednesday morning. .LONG TERM...(Thursday through Tuesday) Issued at 245 PM EST TUE JAN 3 2017 The focus in the extended period will be the Thursday and Thursday night time frame. The model data is finally beginning to come into some agreement regarding the passage of a trough of low pressure aloft Thursday and Thursday night. As of now, the thinking is that an upper trough will move quickly across the Great Lakes region toward the end of the week. A potent shortwave is forecast to move quickly across the Ohio and Tennessee valley regions around the base of the upper low. With cold air already expected to be firmly entrenched across the region, any precipitation that falls Thursday and Thursday night will be in the form of snow. With the models coming into some agreement, and with the latest MOS data having higher pops, decided to increase the precipitation chances for eastern Kentucky Thursday and Thursday night. Also increased the QPF and snowfall amounts as the model data has also trended in that direction. Most locations can tentatively expect between a half inch and an inch of snow Thursday and Thursday night. The higher terrain along the Virginia border may see just over an inch. Areas along and north of I-64 may also pick up around an inch, as the precip is expected to begin there first and will be closer to the center of the passing shortwave. The snow may last into the day on Friday, due to moist upslope flow. After the snow ends on Thursday, it looks a dry forecast through the beginning of next week. Temperatures will be running below normal across the area, with daily highs in the 20s and 30s expected each day. Nightly lows should be in the teens and 20s on Friday, and in the teens Saturday through Monday. Conditions should improve slightly for Monday and Monday night, with highs forecast to warm into the upper 30s and lower 40s, and lows in the 20s expected. A few location in our higher terrain may even fall into the single digits Sunday and Monday morning. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) ISSUED AT 638 PM EST TUE JAN 3 2017 A cold front now located across central Kentucky will continue pushing eastward across eastern Kentucky this evening. Ahead of the front, numerous showers will be found with ceilings varying from low MVFR to IFR. Behind the front, ceilings are expected to drop to LIFR and the showers will transition to areas of drizzle. Ceilings will then trend upward late tonight into Wednesday morning as colder/drier air starts to advect into the region in the low levels. This should result in a return to MVFR ceilings shortly after dawn and then a scattering out of the clouds from west to east during the late morning. TAFs portray the above expectations but confidence on the timing of the category changes is low. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...ABE SHORT TERM...GREIF LONG TERM...AR AVIATION...ABE
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
911 PM CST Tue Jan 3 2017 .SYNOPSIS... Issued at 307 PM CST Tue Jan 3 2017 A more zonal H5 pattern has developed across the western CONUS over the past 24 hours. A strong shortwave remained off the coast of Oregon, however, 50+ meter HT rises were noted over the pacific Northwest into Idaho and northern Nevada this morning. With this noted, the feature off the coast of Oregon, should remain stationary over the next 24 hours. West of the west coast shortwave, a positively tilted ridge of high pressure extended from the Gulf of Alaska into northwestern Nunavut Canada. East of the apex of the ridge, a closed low was present over northern portions of Hudson Bay. On the western and southwestern periphery of the low, two shortwave troughs were present, one due west of the low and a second which extended southwest of the low into southwestern Canada. At the surface, arctic high pressure was anchored over southeastern Montana and extended south southeast into northwestern Nebraska. With the exception of some thin mid and high clouds in association with a jet streak, skies were mostly clear to partly cloudy. Temperatures were cold across western and north central Nebraska with 3 PM CST readings ranging from 9 at Valentine to 20 at Imperial. && .UPDATE... Issued at 910 PM CST Tue Jan 3 2017 The faster RAP and HRRR models are handling the snow across Wrn Neb the best. A new forecast is in place for the developing snow using a blend of those two models plus the previous forecast. Snow production shown by the webcams in the Scottsbluff area look good. && .SHORT TERM...(This evening through Wednesday) Issued at 307 PM CST Tue Jan 3 2017 Clouds will be on the increase tonight as mid level moisture spreads eastward across the area. Lower clouds (stratus) will also develop across portions of the panhandle through southwest Nebraska by daybreak Wednesday. Northern Nebraska will be the last to see the clouds increase tonight, and will drop a few degrees below zero. These areas will also see the coldest wind chills and a wind chill advisory will remain in effect. Mid level frontogenesis will strengthen Wednesday morning, and snow will develop in a band from western through southwest Nebraska by noontime. Cross sections indicate the potential for some banded moderate snow intensities, and expect a general 1 to 3" inches with an isolated higher amount near 4" not out of the question. This is mainly due to the dry powdery nature of the snow. Winds will be light and blowing snow will not be an issue. Across portions of central and especially north central Nebraska, drier air in the lower levels will limit snow to just light or flurries. Little accumulation is expected for these areas. .LONG TERM...(Wednesday night through Tuesday) Issued at 307 PM CST Tue Jan 3 2017 Wednesday night through Friday: In the mid range, lingering snow chances Wednesday night and temperatures are the main forecast challenges. Decent mid level frontogenesis and isentropic lift on the 285K surface, will continue into the evening hours across the southern half of the forecast area. Both the latest NAM12 and GFS solutions are in decent agreement with the location and southward track of this lift into the overnight. QPF forecasts for tomorrow evening are on the order of five to ten hundredths for North Platte during the evening hours. Utilizing a 18-1 ratio of snow to rain, yields around an inch to an inch and a half for North Platte. Add this to what is expected Tuesday afternoon and North Platte is looking at around two inches of snow. Some higher amounts of up to 3 inches are possible in Garden and Deuel County. With light winds expected Tomorrow afternoon and Wednesday night, will forgo a winter weather advisory since snowfall is on the order of 1 to 3 inches. Across northern Nebraska, a reinforcing shot of arctic air will push into the area overnight. By Thursday morning, lows will range from zero to 12 below zero over the Pine Ridge. With the weak cold air advection Wednesday Night, winds will not totally decouple overnight. That being said, northerly winds around 10 MPH will combine with below zero temperatures, producing wind chills as low as 15 to 30 below zero across the northern half of the forecast area. This will probably necessitate the eventual issuance of a wind chill advisory for Wednesday night. This area is already covered with a wind chill advisory for tonight, so will hold off issuance till tonight to avoid confusion. On Thursday, cold air will remain anchored across western and north central Nebraska as high pressure builds across the sandhills. With respect to highs, Thursday will be the coldest of the next 7 days with highs in the single digits to the lower teens. Fresh snow cover across southwestern Nebraska will limit highs as well. High pressure will drift southeast into Kansas Thursday night, forcing the coldest air to the south and east. With clear skies and light winds in place, lows will bottom out in the -2 to -12 degree range and may need to be adjusted even lower across southwestern Nebraska where fresh snow cover will reside. Friday night through Tuesday: Ridging aloft will begin to build into the Rockies and Plains into the weekend. After highs in the 20s Saturday, readings will trend upward into the 30s Sunday, followed by 40s on Monday and Tuesday. With the exception of some slight chances for precipitation Tuesday, the extended periods will be dry. The warmup appears short lived however, as another arctic front may arrive late next week. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 538 PM CST Tue Jan 3 2017 The radar returns in central WY are expected to move east and expand in coverage across the Nebraska Panhandle and Western Sandhills tonight. It is believed this area of snow will move east Wednesday morning affecting I-80...KLBF and the Central Sandhills. IFR is expected to become widespread in light snow and low cigs. The RAP model and HRRR suggest an area of MVFR in snow and low cigs will develop and affect KLBF 06z-12z. This is under review. There is also an area of MVFR cigs over the Cheyenne divide right now shown by sfc obs and this area of low clouds is being monitored as a possible area of snow development this evening. Lastly...the SREF shows IFR in snow not affecting KLBF and I-80 directly Wednesday but casts this area of snow farther north toward KTIF. Thus there is uncertainty as to where exactly the snow will develop tonight and Wednesday and the solution to this problem will not be understood until later tonight or Wednesday morning once the snow band develops. && .LBF WATCHES/WARNINGS/ADVISORIES... Wind Chill Advisory until noon CST /11 AM MST/ Wednesday for NEZ004>006-094. && $$ UPDATE...CDC SYNOPSIS...Buttler SHORT TERM...Taylor LONG TERM...Buttler AVIATION...CDC
Area Forecast Discussion
National Weather Service Marquette MI
535 PM EST Tue Jan 3 2017 .SHORT TERM...(This evening through Wednesday) Issued at 406 PM EST TUE JAN 3 2017 WV imagery and RAP analysis indicated a mid/upper level low near KINL. A surface trough extended from low pres over Lake Erie through Lake Huron and eastern Upper Michigan to central Lake Superior. Westerly flow behind the trough was bringing in drier through the western cwa. Some weak LES bands have developed over wrn Lake Superior limited by marginal instability (850 mb temps around -10C) and relatively dry air upstream over ne MN. Tonight, satellite trends and short range high res models suggest that the stronger LES supported by low level conv near the low and trough axis over nrn Lake Superior will be slower to slide southward into the nw cwa with a heavier burst of snow over the west arriving mainly between 03z-06z. However, expect at least light to moderate snow this evening. Similarly, the trough may also arrive later into the ne cwa between 09z-12z/Wed. Once the winds veer to the nw the deep moisture, colder air (850 mb temps to near -20C) and the arrival of 700-300 mb qvector conv with the mid level low will support stronger LES. The DGZ position in the convective layer will also be favorable for snow growth with higher SLR values. 3 to 6 inch amounts will be common. So, no significant changes were made to the warnings and advisories other than to mention the later arrival of the heavier snow. Wednesday, multiple wind parallel LES aligned with cyclonic 320-340 flow will bring the heaviest snow into the west in the higher terrain between IWD and CMX and over the east from P53 eastward. Although the DBZ drops closer to the surface, the deep instability with the departing mid level low will still support moderate to heavy accumulations with 3 to 6 inch amounts again in the nw flow favored locations. In addition considerable blsn is expected in exposed locations near the Lake. .LONG TERM...(Wednesday night through Tuesday) Issued at 253 PM EST TUE JAN 3 2017 The main forecast highlights Wednesday night through early next week are persistent LES into this weekend across the west and northwest wind snow belts and the arrival of bitterly cold arctic air, before another system is progged to lift into the region next week bringing a chance for system snow across the area. Wednesday night into Thursday expect moderate to heavy LES to continue with models showing ample lift through the dendritic growth zone early on. Expect blowing snow to also be an issue in locations that see LES. As we progress through the overnight hours and Thursday much colder 850mb air wraps around the occluded system, lifting north across eastern Canada, and will allow for a bitterly cold arctic airmass to move over the region. This colder air will allow snow ratios to lower throughout the end of the week as forecast soundings show the thickness of the dendritic growth zone thinning. This coupled with winds backing a bit west-northwest still thinking that a few periods of moderate LES will be possible through Thursday/Thursday night, but the heaviest snowfall should occur Wednesday night into Thursday. Temperature wise, the middle of the week into the weekend looks bitterly cold with overnight lows dropping into the single digits and even below zero across the higher terrain. Afternoon highs are only expected to reach the single digits across western portions of the area with teens across the east. Thursday night into Friday morning although the winds are expected to lessen, the remnant winds and bitterly cold air will allow for wind chills to drop to around -22 to -26, approaching advisory criteria. Through the end of the week and into the weekend, LES will continue to shift into the west wind snow belts before gradually weaken and move offshore towards the end of the weekend. Early next week 850mb winds will back to the southwest with return flow advecting northward ahead of a system progged to lift north across the region. This will also allow temperatures to gradually warm back up into the 20s towards the end of the weekend/early next week. In regards to the system for next week, there is good agreement amongst the GFS/ECMWF with the system swinging through the region Tuesday into Wednesday. Even though soundings show a stout warm nose advecting overhead, at this time it does not look 850mb temperatures will be warm enough to promote melting of ice crystals, so have opted to keep mentions of all snow for now. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 535 PM EST TUE JAN 3 2017 Conditions will drop this evening and overnight at IWD and CMX to IFR in moderate to heavy lake effect snow and blowing snow in the wake of a strong cold front. SAW will likely see improvement to high end MVFR or low end VFR this evening as winds shift to a downslope westerly direction. MVFR conditions and some lake effect snow will return to SAW late tonight as cold front moves through the area. Conditions at SAW will fall to IFR Wed morning into Wed afternoon with the lake effect snow showers. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 406 PM EST TUE JAN 3 2017 As a trough deepens over the lake and colder moves in behind it, northwest gales to 35 knots are expected across the lake beginning this evening in the west and later on tonight in the east. Gales will diminish Wed morning over the west, but will continue through much of Wed over the east half. Expect northwest winds of 20 to 30 knots Wednesday night to diminish to 15 to 25 knots Thursday then become more westerly on Friday. There is a potential for heavy freezing spray Wednesday into Friday as Arctic air moves over the area. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Lake Effect Snow Advisory from 9 PM this evening to 7 PM EST Wednesday for MIZ004-084. Lake Effect Snow Warning from 1 AM Wednesday to 7 AM EST Friday for MIZ006-007-085. Lake Effect Snow Warning until midnight EST Friday night for MIZ001>003. Lake Effect Snow Warning until noon CST Thursday for MIZ009. Lake Superior... Heavy Freezing Spray Warning from 4 AM Wednesday to 10 AM EST Thursday for LSZ265>267. Gale Warning from 4 AM to 4 PM EST Wednesday for LSZ249>251-266- 267. Gale Warning from 1 AM to 1 PM EST Wednesday for LSZ243>245-248- 264-265. Heavy Freezing Spray Warning from 1 AM Wednesday to 10 AM EST Thursday for LSZ264. Gale Warning from 9 PM EST /8 PM CST/ this evening to 7 AM EST /6 AM CST/ Wednesday for LSZ162-240>242-263. Heavy Freezing Spray Warning from 1 AM EST /midnight CST/ Wednesday to 4 AM EST /3 AM CST/ Thursday for LSZ162-263. Lake Michigan... Gale Warning from 10 PM this evening to 5 PM EST Wednesday for LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...Ritzman AVIATION...07 MARINE...JLB
Area Forecast Discussion
National Weather Service Nashville TN
741 PM CST Tue Jan 3 2017 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Cold front currently working across eastern middle TN at this hour. Scattered light shower activity is primarily located along and east of the boundary. Temperatures have dropped into the upper 40s across northwest areas and the caa is still expected to continue area wide overnight. Upper level energy in the post frontal sector is rather weak and the vorticity advection has gone negative across our northwestern areas where little if any rainfall is now occurring. Latest Hrrr and model data shows that the precipitation should continue to gradually decrease through 12z from west to east. Looking at the current weather grids, I see no reason to make any modification at this point. Remainder of fcst appears to be in good shape as well. Although, latest 12z temp progs are running a little lower than our fcst min temps. Will go ahead and lower min temps a degree or two. update out shortly. && .AVIATION... 00Z TAF DISCUSSION. As sfc cold front pushes thru mid state, mainly along and ahead, some light shwrs will be possible, in at least vcnty of terminals. Vicinity of shwr potential will dissipate after 04/05Z. However, it will take some time before IFR to MVFR ceiling erosions to take place, as strong sfc ridging influences try to build in from the northern Rockies thru 04/24Z. It looks like ceiling erosions will occur slowly from west to east from around 04/10Z west to around 04/19Z east, as a weak upper level trough passage and dry quasi zonal flow aloft become established thru 04/24Z. Sfc gusts before and shortly after frontal passage up to 20kts should generally subside between 04/12Z-04/18Z as sfc pressure gradient finally weakens and winds become predominate nwly 5 to 10 kts. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......21 AVIATION........31
Area Forecast Discussion
National Weather Service Springfield MO
610 PM CST Tue Jan 3 2017 .SHORT TERM...(This evening through Wednesday) Issued at 206 PM CST Tue Jan 3 2017 Cloud cover, fog and patchy drizzle persisted across the area this afternoon. A sharp clearing line was moving slowly southeast across Eastern Kansas and Northwest Missouri. This delineates a drier airmass moving toward the area. Northwest upslope flow along the Ozark Plateau typically suggests that this clearing line will struggle tonight to move through. The RAP 850mb-925mb layer RH is handling the location of the clearing well however we have slowed down the clearing line through the area more than short term models suggest. Patchy fog may persist into the evening mainly along and south of Interstate 44 however with winds remaining up an drier air advecting in with time do not expect any dense fog. Low temperatures will ultimately depend on cloud cover tonight however with continue cold air advection temps should still fall into the teens in most places. Temps on Wednesday will likely remain at or slightly below freezing. .LONG TERM...(Wednesday Night through Tuesday) Issued at 206 PM CST Tue Jan 3 2017 A shortwave trough will move down from Montana into the Northern Plains late Wednesday. Sufficient lift and mid level moisture with this feature will combine to produce a band of light snow mainly between US Highway 54 and Interstate 70 in Central Missouri. QPF amounts look very light however with high SLR around 16-17:1 there could be a quick 0.5 to 1 inch mainly along and north of US Highway 54 late Wednesday night into early Thursday morning. Both the NAM and GFS keep all precip north of Springfield while the ECMWF and Canadian brings things ever so slightly south. Confidence is increasing that the best chance for snow will be north of Springfield. Any light snow or flurries will likely end during the daytime Thursday. Cold but dry conditions persist for the remainder of the week as high pressure moves in. Both long range models are showing a warming trend late in the weekend into early next week. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 605 PM CST Tue Jan 3 2017 An MVFR cloud deck will clear from northwest to southeast across southern Missouri this evening. While the back edge of the clouds may hang-up for an extra hour or two due to local terrain effects, we are expecting the back edge to clear Branson before midnight. VFR conditions and some high clouds can then be expected overnight and into Wednesday. Surface winds will remain out of the northwest and will slowly diminish this evening. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ SHORT TERM...Burchfield LONG TERM...Burchfield AVIATION...Schaumann