Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/16/19

Area Forecast Discussion
National Weather Service Fort Worth TX
940 PM CST Fri Feb 15 2019 .UPDATE... Evening satellite and surface observations indicate that the cold front has cleared all but our extreme southern counties at this hour and will continue to push south overnight. Low cloud cover has spread across the Red River and will continue southward through the overnight hours. Freezing temperatures have now spread into Montague County and most of our northwest half of the region should be at or below freezing later tonight. The brisk north winds will diminish some by morning. We`ve made some minor adjustments downward to hourly temperatures across the region based on latest observations. The main change with this update will concern Saturday`s high temperature forecast. As mentioned in the afternoon AFD, the temperature forecast will be tricky given the strengthening southwesterly flow and strong warm advection expected to spread into our western counties by afternoon. Latest high resolution guidance however, suggests that the frontal inversion will be a little deeper with saturation through 3000 ft. Atop the frontal inversion will be a subsidence inversion with 850mb temps climbing to +15C. Despite the strengthening southwesterly winds and some erosion of cloud cover across our far western counties, we think the colder air will be a little more difficult to erode across a good portion of Central and North Texas. We`ve followed the general trend of the SREF/NAM/TTU-WRF guidance downward with high temperatures through tomorrow afternoon. We`ll keep highs in the low to mid 40s across much of the region, but we`ll maintain a tighter gradient in temps across the southwestern counties where it still looks like highs in the 60s will be possible. Dunn && .AVIATION... /Issued 548 PM CST Fri Feb 15 2019/ /00Z TAFs/ Concerns -- Decreasing cigs overnight and into morning. MVFR likely. IFR possible. Winds returning to S flow by Saturday afternoon. An arctic cold front continues to make its way across Central TX with N flow now in place at all TAF sites. Sustained winds are around 10-15 KT with a few gusts to around 20 KT being reported during the past few hours. Visible satellite imagery reveals a vast post-frontal stratus deck over OK/KS with a number of METAR sites reporting MVFR and even IFR cigs. This cloud deck should make its way into the D10 TRACON during the overnight hours...with North TX TAF sites likely becoming MVFR by 16/1000Z. RAP and NAM soundings are fairly aggressive with low-level moistening during the morning hours...and some IFR cigs are not out of the question. At this time...confidence was not high enough to include in TAFs...but cigs may need to be lowered further in later TAF issuances. By Saturday afternoon...winds should return to S flow as the axis of high pressure behind the cold front moves into the MS Valley and a weak surface low develops in the vicinity of KIAH. Cigs should improve slowly late in the afternoon. Aloft...a potent jet stream digging into the Southern Plains will produce occasional severe turbulence at FL200-300. The strongest turbulence will be found near the axis of the 170+ KT jet which will move out of the Southwest and into the Southern Plains during the next 24 hours. For more information...refer to the latest SIGMET products. Godwin && .SHORT TERM... /Issued 318 PM CST Fri Feb 15 2019/ /Through Tonight/ Big temperature changes coming to North and Central Texas tonight. 1800Z surface analysis revealed a 1004 mb surface low over Dallas. A cold front runs through this surface low out into West Texas, and to the east into southern Arkansas. This cold front demarcates the boundary between continental arctic (cA) air to the north and maritime tropical (mT) air to the southeast of the surface low. The air mass over East Texas is characterized by temperatures in the 70s and dewpoints in the 50s, while the air mass to the north of the cold front over the Sooner State is characterized by temperatures in the 30s and dewpoints in the 20s. The cold front has been shy about moving south through the day with little in the way of upper-level support to encourage it to continue southward. The southward push should begin forthwith however as an upper-level shortwave trough along the lee of the Colorado and New Mexico Rockies ejects into the Great Plains. The cold front should clear Dallas/Fort Worth in the next few hours, and reach the Killeen/Temple/Waco area a little after sundown. Cold air advection behind the front will result in rapidly falling temperatures, with lows tonight expected to drop into the 30s for the northern two-thirds of our forecast area, and into the 40s in our two southeasternmost tiers of counties. A light freeze is expected in rural areas north of Interstate 20 (the urban heat island effect should keep overnight lows in the Dallas/Fort Worth Metropolitan Area just above the freezing mark). While winds will not be particularly strong overnight, northerly winds at around 10 MPH will result in wind chills in the 20s for most areas north of Interstate 20 (including in Dallas and Tarrant Counties). In terms of precipitation potential, the 1200Z RAOB from Fort Worth showed very dry air immediately above the boundary layer ahead of the cold front, with both mid-level and low-level mean relative humidity values below 35%. This lack of moisture should keep precipitation chances near zero through the overnight period. Godwin && .LONG TERM... /Issued 318 PM CST Fri Feb 15 2019/ /Saturday through Next Week/ Main focus of the long-term forecast is the return to a southwesterly mid/upper flow regime through most, if not all, of next week, and a resultant increase in precipitation chances (primarily on Tuesday). Right now, we are not anticipating any significant winter-weather impacts across our area, but surface temperatures will be close to freezing across western North Texas so this area will likely be the largest focus going forward. More info below. In the meantime, Saturday presents another tricky temperature forecast, with a large gradient possible across North and Central Texas. Low clouds, in association with the frontal surface aloft, are forecast across much of the region during the morning hours. Through the day, though, strengthening west/southwesterly flow aloft and increased low-level mixing will advance east across the region. Cloud cover is expected to gradually diminish from west to east through the day, but broken/overcast skies will likely hold steady east of I-35 and north of I-20 into the afternoon/evening. Therefore, forecasting a tight gradient in high temps (mid 70s southwest, near 50 northeast) and these cooler conditions may not be cold enough. Later updates may have to tweak highs downward for locales in the direction of Sherman/Bonham/Paris/Sulphur Springs. Additionally, some patchy drizzle will be possible across East Texas during the day, under the influence of poleward 925mb theta-e advection. A passing front brings a low chance for light showers across East Texas Saturday night. Then temperatures cool on a broader scale Sunday and especially Monday, as high pressure builds over the central/southern Plains in response to building heights aloft behind a Missouri Valley system. Conditions should be relatively dry, although strengthening southwesterly mid/upper flow will likely yield a solid plume of upper-level cloud cover across Texas into early next week. Meanwhile, in the western-US pattern that can`t stop (won`t stop), another strong jet streak will drop south along the Pacific Coast Monday, amplifying an already well- established trough over the Inter-Mountain West. Ahead of this trough, isentropic ascent atop a shallow, cold air mass will stream low-level clouds northward Monday night. Precipitation chances will increase accordingly and should be light initially. Towards Breckenridge/Graham/Bowie, surface temperatures may be close to freezing initially, although guidance continues to suggest any potential for more significant issues will be just northwest of our area. Still, given the proximity of sub-freezing temps and also potential for wet-bulb cooling, have advertised a slight chance of freezing rain across the far west/northwest Tuesday morning. With only marginal surface temperatures, though, believe the potential for significant impacts is low at this time. Expect a cold rain everywhere else on Tuesday, as temperatures range from the mid 30s to upper 40s. The amount of precipitation over Central and North Texas will likely be a function of the amplification of an ejecting mid/upper system over the Plains (related to the jet streak discussed above), given its impact on low/mid- level thermal advection and frontogenetic ascent. The 15/12Z ECMWF cycle suggests a more amplified solution, but this potential remains uncertain. Regardless, a developing cyclone ejects northeast across the lower Mississippi Valley Tuesday night, which should bring drying mid levels and an end to any deeper precipitation processes. There could be a quick mix of light rain/snow (once again across far northwestern areas) before precipitation ends Tuesday night, in tandem with a cooling column behind the aforementioned departing low. Still, not anticipating any notable impacts at this time due to precipitation ceasing before surface temperatures cool dramatically. The region remains under the influence of southwesterly flow aloft and a switch to low-level return flow by late week. Temperatures are expected to modify slowly, but precipitation timing/distribution remains of low predictability, due to the subtle nature of shortwave troughs within the broader synoptic regime. In turn, only show slight rain chances by Friday. Picca && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 33 45 41 60 34 / 0 0 5 0 5 Waco 40 48 43 61 39 / 0 0 5 0 10 Paris 34 46 40 58 33 / 0 0 10 0 5 Denton 31 44 39 57 31 / 0 0 5 0 5 McKinney 32 44 38 58 33 / 0 0 5 0 5 Dallas 35 46 44 60 35 / 0 0 5 0 5 Terrell 35 46 43 60 36 / 0 0 10 0 10 Corsicana 37 50 45 62 39 / 0 0 10 0 10 Temple 42 52 45 64 41 / 0 0 5 0 10 Mineral Wells 31 52 39 60 31 / 0 0 5 0 5 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Hastings NE
523 PM CST Fri Feb 15 2019 .UPDATE... Issued at 409 PM CST Fri Feb 15 2019 Accumulating snow has ended this afternoon, therefore the winter weather advisory has been cancelled. && .SHORT TERM...(This evening through Saturday) Issued at 259 PM CST Fri Feb 15 2019 Snow is on the downturn for today as the shortwave trough continues to move east with the rest of the advisory almost expired. Main focus will be the snow and perhaps a potential for freezing drizzle for Saturday as yet another wave moves through, acting as a spoke for the parent upper low parked over southeastern Alberta. As for freezing drizzle chances, I`m holding off on including this in the forecast as only are far south indicates mid-levels drying out at anything warmer than -10C, and even if snow does not form aloft, there looks like a probable refreeze of any supercooled droplets as most sounding point toward temps below -10C before droplets would hit the ground, giving us snow grain type precip. Midnight shift will have the final call on this. We will have good warm air advection aloft to pay attention to, and we will have to pay particular attention to refreeze potential if we deem it possible for supercooled droplets to form aloft instead of snow. Although the overall synoptic lift and mixing ratios will be more than with this next wave compared to what we had today, we will have lower precipitable water and lower snow to liquid ratios that will knock down overall snow totals to what we had today, as higher snow amounts will be well to the north and northeast. It looks like we should top out just over two inches in our far north/northeast CWA for Saturday. Light snow showers/flurry activity could very well last into Sunday/Sunday evening time frame. All and all went a few degrees colder than guidance and Superblend as fresh snow has fallen, and models that handle well below normal temps also indicate this. HRRR and SREF hint at some fog, but cloud cover and a little bit of wind should help keep most of this away, but we`ll need to watch as we will be getting some upslope flow. .LONG TERM...(Saturday night through Friday) Issued at 259 PM CST Fri Feb 15 2019 More small chance of snow occur for Monday/Tuesday, with more waves coming through but amounts do not look large. We will remain below normal for the entire forecast. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday) Issued at 518 PM CST Fri Feb 15 2019 The first round of snow has ended for the terminals, with the next round of snow expected to begin Saturday afternoon. In the interim between systems, clouds are expected to lower to MVFR this evening and a period of IFR conditions cannot be ruled out. Have some concern for the potential for fog development but there is not a consistent signal for fog at this point and will monitor. The brunt of the snow Saturday is forecast to fall Saturday evening. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ UPDATE...Fay SHORT TERM...Heinlein LONG TERM...Heinlein AVIATION...Fay
Area Forecast Discussion
National Weather Service Grand Rapids MI
935 PM EST Fri Feb 15 2019 LATEST UPDATE... Update .SYNOPSIS... Issued at 139 PM EST Fri Feb 15 2019 - Colder than normal Saturday through Tuesday - Chance of light snow Sunday - Impactful system possible Wednesday with accumulating snow && .UPDATE... Issued at 935 PM EST Fri Feb 15 2019 The ongoing forecast looks fine and needed few adjustments. However I through it good to address the break in the clouds that developed over central lower Michigan just before sunset. This occurred because it was where the cloud level winds switched from west to northwest. So in the area near where the wind shifted it was considerable divergence in the air at cloud level. So that cleared the clouds for a short awhile. However, there is actually a shallow cold front (which shows up nicely on the 925 mb chart from the RAP) near the north shore of Lake Superior. This boundary pushes south overnight so that creates an area of weak lift as the "cold front" pushes south across lower Michigan overnight. Thus the clouds fill back in for a time. This is seen on both the RAP and NAM models very nicely. Once the cold air arrives winds turn more north northeast and that brings subsidence and dry air from southern Canada into this area. The air is dry enough that Lake Huron should not allow much low clouds to reach our NE or eastern CWA. So I expect skies to clear from northeast to southwest overnight as this shallow cold front moves through the area. A few flurries are not out of the question but I did not put that in the forecast as whatever would happen would be hard to notice even if you were outside when it was happening. Bottom line is clearing late tonight with colder air moving in from the north. && .DISCUSSION...(This evening through next Friday) Issued at 139 PM EST Fri Feb 15 2019 Overall the pattern is looking relatively quieter than it has been into early next week, but another storm system is on the horizon with some impacts looking more likely with time. The models are in relative agreement in tracking a mid level wave in from the southwest on Wednesday. This system will have Gulf moisture with it so the combination of lift and moisture will support widespread precipitation. Forecast soundings keep it snow. The strongest lift and most favorable moisture do remain south of the border. While we are not forecasted to be in the zone for heaviest snow....a widespread accumulating snow looks likely for the area. That typically results in some impacts especially around the commutes. We will need to monitor trends closely as a risk for heavier snow does exist...mainly with a coupled upper jet in the area on Wednesday. For now...we will continue to feature high POPs and mention the potential impacts in our products. The storm system on Sunday will be driven by a mid level wave that will be tracking eastward through the Central Plains Saturday night. This wave will be losing amplitude as it enters the Great Lakes Region on Sunday. Even though it may tap Gulf moisture for a short period of will be accelerating. In addition a rather strong east northeast low level flow may act to keep the low levels dry enough to limit the potential for accumulations. We will keep that risk low at this time. For the rest of the period...the snow showers and wind have been slowly diminishing early this afternoon. That trend will continue for the remainder of the afternoon into the evening. This is because the moisture depth will be decreasing and the pressure gradient weakening with time. Clouds may struggle to break up until later tonight into Saturday morning...which may limit how low temperatures go. If skies clear out sooner we may have to lower temperatures. Saturday looks dry with a fair amount of sunshine and much less wind as high pressure tracks eastward through the state. Colder than normal temperatures will continue with the cold air advection persisting. For Monday and Tuesday a large arctic high pressure system drops out of the Canadian Prairies into the Northern Plains. This...combined with the snowpack could support very cold overnight temperatures early next week. There is some risk for lake effect on Monday as the arctic air advects in. However this potential should be limited with subsidence from this high pressure system overspreading the region...and also that the airmass will be mostly drying out with time. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 651 PM EST Fri Feb 15 2019 Currently (2340z) all GRR TAF sites have MVFR cigs but our nighttime microphysics image loop shows an area of expanding clear skies just north of I-96 from North of MKG to North of MBS. The area of clearing should continue to expand north and south over the next few hours to allow most of the TAF sites to become mostly clear in the 03z to 06z time frame. The clearing is where the surface winds become northwest from west (where clouds are still). Seems once the surface winds become north some of the clouds now over northern lower Michigan may briefly move back in. That would be in the 06z to 12z time frame. However, with the exception of MKG, I would expect skies to be mostly clear (after 12z) Saturday as that is typical of what lake effect clouds do when surface winds are from the north. && .HYDROLOGY... Issued at 325 PM EST Thu Feb 14 2019 Nearly all rivers in our area have now crested after responding to the volatile weather of the last 2 weeks. Many streams have now fallen below bankfull levels, but parts of the Grand River (Ionia, Lowell), Looking Glass River (Eagle), Maple River (Maple Rapids), and Pere Marquette River (Scottville) remain above bankfull but have been gradually falling. There continues to be a major ice jam causing ongoing flooding in the City of Portland. Water levels there will continue to fluctuate up and down in response to shifting and changing ice conditions. There is another ice jam that we are monitoring near Eastmanville, near the 68th Avenue bridge. This ice jam is currently fairly small, and is not currently resulting in additional flooding. There are no ice jams in the Grand Rapids area, but we are still monitoring that potential as the water will remain high for at least several more days. A combination of light rain and snow late Thursday through Friday followed by cold temperatures will maintain the river ice and the water contained in the snowpack. Precipitation amounts from the weekend through the middle of next week also look light. No significant warmups are expected to cause any appreciable melting of snow. && .GRR WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...WDM SYNOPSIS...MJS DISCUSSION...MJS AVIATION...WDM HYDROLOGY...AMD/CAS
Area Forecast Discussion
National Weather Service Louisville KY
947 PM EST Fri Feb 15 2019 .Forecast Update... Issued at 940 PM EST Fri Feb 15 2019 Latest Doppler radar trends shows that precip has really diminished over southern IN and the northern half of central KY at this time. Note that cloud bases rose after the initial northern band of snow dissipated. Meanwhile, KY Mesonet obs show temps have been quasi- steady lately over central/south-central KY, with values 33-35 over south-central KY and mid-upper 30s in our far southeastern counties where no Advisory exists. BWG has been reporting light rain, and we have received reports of mixed precip at times where radar shows higher returns over south-central KY now. Meanwhile, the St. Louis and Evansville radars show more precip still to the west of us, with a slight drift north of east. This could suggest that some light snow could again move into parts of north-central KY and perhaps into south-central IN later this evening/overnight. The new 00 UTC NAM12 and NAM3 along with latest HRRR models pick up on this, with the northern edge of measurable precip roughly from Hancock/southern Perry counties eastward to south of I-64 to about Lexington, with higher amounts south of that line. With current trends and the latest high res model output, it seems prudent to cancel the Winter Weather Advisory for a row of counties on its northern edge. This includes Dubois, Crawford, Harrison, and Floyd counties in Indiana, and Jefferson (including Louisville), Shelby, Franklin, Scott, Bourbon, Nicholas, and Harrison counties in central Kentucky. Will keep Advisory for Lexington for now pending latest radar trends later this evening into the overnight. Meanwhile, based on current surface temps and forecasted lows overnight over our far southeastern counties, see no real reason to expand Advisory into those 5 counties near the TN border. Overall, made some adjustments to POPs and QPF amounts overnight. Improvement occurs on Saturday. && .Mesoscale Update... Issued at 645 PM EST Fri Feb 15 2019 Latest radar shows that precip has overspread our forecast area and will reach the ground in all areas in central KY shortly. There has been a small northern band of snow for the last hour or so bringing temporarily lower visibilities/rates than what models suggested but will likely weaken and not affect the current Advisory. A tight gradient to flurries or nothing exists over our eastern counties in south-central IN as expected. A more persistent band of precip with higher reflectivity returns exists over our west-central KY counties. Within this band, current dual pol correlation coefficient (CC) data suggests that a mix of precip or varying types is likely occurring from Grayson and Hart counties southward. Expect precip to continue for the next several hours across central KY. No forecast changes at this time. && .Short Term...(This evening through Saturday) Issued at 310 PM EST Fri Feb 15 2019 ...Minor Snow Accumulations Tonight... Broad snow shield taking shape across Missouri and parts of southern Illinois ahead of an upper shortwave trof moving quickly eastward across Kansas. Snow to rain/freezing rain transition lays out from the Ozarks into the Missouri Bootheel. The area of snow will pivot eastward across the Ohio Valley later this evening as the upper impulse scoots through, producing 1-2 inch accumulations, perhaps with some locally higher amounts. Confidence in the snow forecast is decreasing, especially along the northern edge, because the sfc reflection appears weaker and farther south. The greatest accumulations will be roughly along a line from Hartford to Elizabethtown to Richmond, but there could be localized totals of 2 inches or more within that area. Best window for accumulations still looks to be late evening to shortly after midnight, likely with a period of moderate snow that will cover even treated roadways. Will clip a few counties out of the Winter Weather Advisory north of Interstate 64 even though they could still see a dusting to a half inch. Dubois County is tricky given a much colder start this morning, which makes impacts more likely from otherwise meager snowfall. Will cover the cancelled areas with a Special Weather Statement. Southern edge will be kept as-is, given that we still stand to lose ice aloft after midnight, leading to a period of freezing drizzle. The precipitation is expected to quickly move east of the forecast area by dawn Saturday. Recovery in temps during the day will be slow at first due to cloud cover, but should rise above freezing by midday and touch 40 in the afternoon. .Long Term...(Saturday night through Friday) Issued at 330 PM EST Fri Feb 15 2019 The weather starts dry late on Saturday evening, but that looks to change during the early morning hours of Sunday. Weak upper level ridging gives way to a compact wave over the Missouri Valley. An easterly sfc wind will be maintained with overrunning precip developing between 06-12z Sunday. Temperatures are forecast to be fairly steady in the low to mid 30s Sunday morning over the northern half of the area, with the southern half of the area warming into the upper 30s/low 40s. So still looking at a brief wintry mix possible over the northern half of the area to start the day, but accumulations are unlikely at this point. Temperatures continue to rise through sunrise, with all rain in southern Indiana by 15z or so. The rest of Sunday looks to feature some light rain, especially east of I-65 during the afternoon. Afternoon highs will be in the 40s to low 50s. A period of dry weather is still likely Sunday night through Monday night, possible Tue morning. Highs on Monday are shaping up to be in the low to mid 40s. Heights amplify over the eastern U.S. during this period in response to a substantial trough over the Intermountain West. This robust wave will eventually pivot northeast toward the Upper Midwest. Meanwhile, an effective warm frontal boundary should set up near or perhaps just south of central KY (models differ somewhat). The axis of heaviest rain will shift between now and then, but there is potential for moderate to heavy rain Tuesday afternoon through Thursday. Forecast confidence is very low beyond next Thursday. && .Aviation...(00Z TAF Issuance) Updated at 640 PM EST Fri Feb 15 2019 Latest radar shows light snow streaking across parts of south- central IN and central KY, with light rain over parts of south- central KY. Where modest bands of snow occur, ceilings drop temporarily to MVFR, with MVFR or even IFR vsbys at times. This will continue to be the case for the next few hours with conditions improving to VFR first at HNB then late this evening or around midnight or just after at SDF. Conditions at LEX will deteriorate to MVFR a little later this evening as light snow moves in. At BWG, light rain should mix with some sleet and perhaps a little snow this evening, and probably change to some light freezing rain or drizzle late tonight, with MVFR ceilings and vsbys. Conditions improve for all TAF sites by Saturday morning with VFR conditions and the return of some sunshine. Surface winds will be from the north tonight at up to 10 kts, then become NE on Saturday. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...Winter Weather Advisory until 6 AM CST Saturday for INZ089. KY...Winter Weather Advisory until 7 AM EST /6 AM CST/ Saturday for KYZ023>029-038>041-045>049-053>057-061>067-070>072-074-076- 077. && $$ Mesoscale....TWF Update.......TWF Short Term...RAS Long Term....EBW Aviation.....TWF
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
853 PM CST Fri Feb 15 2019 .UPDATE... Issued at 837 PM CST Fri Feb 15 2019 Evening analysis showed dry air advection at the surface and 925 mb which has helped to keep northeast Missouri and west central Illinois snow free. The mid level trough was located over west central Missouri which the RAP shows moving east of the CWA by 06Z. Radar imagery and surface observations indicate that most of the snowfall is mainly light across the area. The most likely location for some moderate snow or sleet is over southeast Missouri which will likely move out of the CWA shortly. These trends fit in with the going forecast, so will start canceling counties early as needed or allow the advisory to expire on time as the snow ends from west to east. Britt && .SHORT TERM... (Through Late Saturday Afternoon) Issued at 235 PM CST Fri Feb 15 2019 The primary concern in the next 24 hours is the ongoing wintry precipitation across much of central and eastern Missouri into southwest Illinois. Latest short-range model runs including the RAP, GFS, and NAM are showing lingering bands of low level frontogenesis into the late evening...mainly south of I-70 across southeast Missouri. The latest runs of the HRRR and 4km NAMNest bear this out with lingering simulated reflectivity past 03-04Z. I have therefore kept some higher PoPs across the aforementioned portions of the forecast area into mid-late evening. That being said, precipitation rates should be tailing off during this period as the main shortwave moves east of the Mississippi river. Forecast soundings indicate some drying in the ice crystal growth zone aloft before the precipitation ends, so a little light mix of sleet or freezing rain in parts of southeast Missouri still looks possible. Current thinking is that there will be an additional 1-2 inches along a band from around California to Farmington with lesser amounts to the north and south of the band. Some sleet and a light glaze of ice is also possible along and south of a line from Bourbon to Farmington. Once the precipitation stops we should have a period of quiet weather tonight and Saturday. High pressure centered over the Upper Midwest will drift eastward Saturday which will turn the flow around to the east-southeast. With at least partial sunshine across much of the area ensemble MOS temperatures highs warming into the low to mid 30s look reasonable. Carney .LONG TERM... (Saturday Night through Next Friday) Issued at 235 PM CST Fri Feb 15 2019 An active weather pattern is anticipated during the extended forecast period. The PV anomaly which is expected to affect our region on Saturday evening was noted over northern CA early this afternoon on water vapor imagery and the RAP 1.5 PVU analysis field. This feature was located to the south of a closed upper low which was centered slightly west of the OR/WA coastline. The observed position of both features agrees well with model forecasts at 18z. Models are in good agreement that the PV anomaly dives southeastward and reaches the Four Corners region by 12z Sat. The upper anomaly and its induced surface low are then forecast to lift through OK/KS towards MO/IL. Models also show one or two smaller disturbances which dive into the trough axis, producing an elongated vorticity zone or shear axis which lingers across the region and subsequently prolongs precipitation chances across the northern CWA. BUFKIT soundings have been inconsistent with the presence of cloud ice and the depth/intensity of a warm layer aloft during this event. Taken as a whole, model guidance suggests that precipitation should begin as snow on Saturday evening across most of the region and then end as freezing rain or freezing drizzle due to the loss of cloud ice. Around 1-2" of snow is expected across the northernmost part of the CWA from 6pm Sat through 6am Sun followed by a light glaze of ice on Sunday morning. Around 1/2" of snow is expected along with a light glaze of ice on Sat night in an E-W band stretching from central MO through east- central MO and into southwestern IL. Eventually, the trough over the west coast will break down and/or shift eastward, and model solutions over the last several days have offered a veritable cornucopia of possible ways in which this pattern change might occur. At least one or two low pressure systems are expected to affect the region next week during the upper air pattern transition, but there is low certainty regarding timing, precipitation types, and precipitation amounts. For this reason, a general rain/snow mix was preferred for precipitation forecasts beyond Sunday. There will be little change in temperatures during the extended forecast period. Highs are forecast to be in the 30s to 40s on most days, and lows will be in the 20s to around 30. However, there is low certainty regarding the temperature forecast during the middle and end of next week due to the aforementioned model disagreements. Kanofsky && .AVIATION... (For the 00z TAFs through 00z Saturday Evening) Issued at 544 PM CST Fri Feb 15 2019 Large area of snow will move out of KCOU and the St. Louis area terminals from west to east this evening. Ceilings and visibilities will improve from IFR/MVFR to VFR once the snow moves out. Then dry and VFR conditions are expected through at least 00Z on Saturday evening. Northerly winds will veer easterly by the end of the period. An additional 0.5 inch of snowfall will be possible at KCOU and the St. Louis area terminals. SPECIFICS FOR KSTL: Snow will move begin diminishing and the move out of the terminal between 03-05Z. Ceilings and visibilities will improve from IFR/MVFR to VFR once the snow moves out. Then dry and VFR conditions are expected through at least 00Z on Saturday evening when additional snow will develop by mid evening. Northerly winds will veer easterly by 00Z on Saturday evening. An additional 0.5 inch of snowfall will be possible this evening before the snowfall ends. Britt && .LSX WATCHES/WARNINGS/ADVISORIES... MO...Winter Weather Advisory until midnight CST tonight for Audrain MO-Boone MO-Callaway MO-Cole MO-Crawford MO-Franklin MO- Gasconade MO-Iron MO-Jefferson MO-Lincoln MO-Madison MO- Moniteau MO-Monroe MO-Montgomery MO-Osage MO-Reynolds MO- Saint Charles MO-Saint Francois MO-Saint Louis City MO- Saint Louis MO-Sainte Genevieve MO-Warren MO-Washington MO. IL...Winter Weather Advisory until midnight CST tonight for Clinton IL-Madison IL-Monroe IL-Randolph IL-Saint Clair IL- Washington IL. && $$ WFO LSX
Area Forecast Discussion
National Weather Service New York NY
847 PM EST Fri Feb 15 2019 .SYNOPSIS... A cold front passes through this evening, followed by high pressure building in through Saturday night. Weak low pressure passes just south Sunday night and Monday. High pressure builds Tuesday, followed by another low pressure and frontal system mid week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... The okx vwp and radar suggest a strengthening lljet ahead of the cold front. As a result, sct shwrs have been fcst for ern portions of LI and CT, with a few sprinkles wwd to the Hudson Valley. The HRRR and 18z NAM are dry. Areas could trace and not measure. Otherwise, the fcst is on track, with the front entering Orange county and poised to pass thru the cwa thru midnight. Dry weather for the overnight hours as high pressure builds in. Cloud cover and/or strong enough winds will hold low temperatures to above normal levels. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Surface high pressure builds into the region with the flow aloft becoming more zonal. There could still be some lingering mid to high level clouds to start the day, especially for southern sections of the forecast area, otherwise it should turn out to be mostly sunny. Went on the cooler side of the guidance average for high temperatures, but this still places us near normal for this time of the year. High pressure continues to build in for Saturday night with a mostly clear sky. Conditions are more favorable for radiational cooling versus tonight, and combined with a colder air mass, lows are expected to drop into the teens across parts of the Lower Hudson Valley, interior CT, and the Pine Barrens Region in eastern LI. The rest of the Tri-State Area should have lows in the 20s. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Upper shortwave moves out of the upper mid west, passing across the Great Lakes region, then shears out across the northeast Monday. Weak ridge, quasizonal flow then prevails behind this shortwave ahead of western trough that will eventually move across the midwest, weakening as it does so, but amplifying the ridge ahead of it across the eastern states. This trough passes Thursday. At the surface, weak low pressure tracks across the Appalachians Sunday night as high pressure to the northeast yields as mid level confluence gives way to aforementioned shortwave. Another low develops just south over the waters, and quickly passes east by Monday. The position of this low remains in question, and this will dictate whether or not light snow or flurries mixes with or changes to light rain along the coast. As the sfc low departs, a lingering sfc trough lags behind as sheared out shortwave moves across the northeast. Feel the bulk of the snow or rain/snow mix ends, but some lingering light snow or sprinkles cannot be ruled out Monday. Not sure if moisture depth will be sufficient for production of ice crystals, but feel clouds linger, and chance pops are warranted. Forecast amounts of around one to two inches of snow accumulation, with support from latest ECMWF run lending some support. If a mix does indeed occur near the coast, amounts could be lower. Timing Sunday night. High pressure builds across the Great Lakes Monday night and Tuesday, then next low approaches from the southwest for Tue night- Wed. Based on upper steering flow as mentioned, the southern low likely passes well to the west, then NW. Meanwhile, high pressure settles across northern New England, likely resulting in some cold air damming as another low develops along the mid Atlantic. Still a lot of details to iron out here, but snow is possible late Tuesday night/Wednesday, then a changeover to a wintry mix to rain would likely occur Wed night-Thu before ending. Dry Friday behind the system. Temperatures through the period will not vary much. In general, temperatures should remain slightly below normal, but as previous forecast stated, arctic air is not anticipated. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... A cold front moves through the terminals from around 02Z west to around 07Z east. There may be a few scattered showers, however, no impact to ceilings or visibilities are expected. VFR through the forecast period. S to SW wind around 10 kt with shift to the W with the approach of the cold front, and then to the NW with the cold frontal passage. Winds may be around 310 true for several hours from around 04Z to 12Z, with occasional gusts up to 20 kt at the NYC metro terminals. During Saturday winds will be more from the NW to N around 10 kt. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... .Saturday night-Sunday...VFR. .Sunday night-Monday...Chance of snow with MVFR or lower conditions possible. .Tuesday...VFR. .Wednesday...Chance of snow with MVFR or lower conditions possible. && .MARINE... SCA remains unchanged on the ocean. The non-ocean waters should see gusts remaining below 25 kt tngt, with gusts dropping blw 25 kt on the ocean by around midnight. Seas will however remain at advisory levels through the night and into Saturday morning. Sub-advisory conditions then prevail Saturday afternoon and night. Winds will be rather tranquil ahead of weak low pressure Sunday- Sunday night. Behind the low, winds shift around to the N/NW and should increase late Monday-Monday night. As such, ocean seas build slightly before subsiding as high pressure builds and winds lighten again. Winds should increase ahead of the next low and frontal boundary Wednesday. && .HYDROLOGY... There are no hydrologic concerns through the middle of next week. && .EQUIPMENT... NYC Central Park winds are out of service until further notice. Loss of data is due to a severed cable. Parts are on order. NYC NOAA Weather Radio Station KWO35 (162.55 MHz) will remain off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 11 AM EST Saturday for ANZ350-353- 355. && $$ SYNOPSIS...JC/PW NEAR TERM...JMC/JC SHORT TERM...JC LONG TERM...PW AVIATION...MET MARINE...JMC/JC/PW HYDROLOGY...JC/PW EQUIPMENT...
Area Forecast Discussion
National Weather Service Pocatello ID
815 PM MST Fri Feb 15 2019 .SHORT TERM...Tonight through Sunday night. A quick update this evening to allow the Winter Weather Advisories to expire. There is still some light ongoing snowfall in the eastern mountains but the threat of moderate snowfall has mostly ended for tonight. Wind and wind gusts remain fairly elevated but both the NAM and HRRR were suggesting that the surface winds should begin to decouple from the stronger winds aloft after 9 PM, at which time, I would expect most of blowing snow issues to subside. See the previous discussion below. Huston A cold front is moving west to east across the region this afternoon. A line of rain and snow defines the front. As the front continues to move east, an additional 1 to 3 inches of snow with some areas of blowing and drifting snow remain possible. Will cancel the advisory for the central mountains as most of the snow has exited the region, while extending the advisory across the eastern highlands where some models are showing snow hanging on into the early evening hours. Snow showers remain likely for the remainder of the weekend with a weak area of low pressure around. Amounts look rather light, generally an inch possible in any 6 hour period. So impacts look fairly light at this point and am anticipating no warnings or advisories. Valle .LONG TERM...Sunday night through next Friday. A broad trough over the western CONUS will keep the potential of some mountain snow showers Sunday night into Monday. The final trough axis swings through during the day Monday, perhaps spreading snow into the Snake Plain, but with moisture eroding quickly impacts of this activity should be limited. A break in precipitation chances is then expected as we transition from one system to the next arriving Wednesday. Models are not nearly in as much agreement as they were during previous runs with how to evolve the Weds/Thurs system. The 00z GFS digs the next upper low over us and drops it to our south, while the 00z EC cuts it off well to our southwest, splitting the moisture around eastern Idaho. With this in mind, will stick with the blend of models which remains close to the middle of these solutions, in line with ensemble means. After a cold start to the next week, temperatures will slowly moderate through the latter half of the forecast. TAX/TW && .AVIATION...A cold front is moving through the area. It has gone through KSUN and mostly through KBYI. Expect VFR conditions to return quickly for these stations. The front is now moving through KPIH and will soon move through KIDA. There is some lightning associated with this front, especially for KPIH and KIDA. THe front will reach KDIJ by 23z. Expect IFR conditions and breezy to moderate winds as this front moves through. Models show a return to VFR conditions by late this afternoon for KPIH and little later into early evening for KIDA and KDIJ. The NAM12 is suggesting light snowshowers and MVFR conditions early in the morning while the GFS model is showing early tomorrow afternoon. TW && .HYDROLOGY...An avalanche occurred near Hailey on Thursday. Snow is blocking the Big Wood River at Hailey and water is being diverted towards some homes. A flood warning remains in place until further notice. Valle && .PIH WATCHES/WARNINGS/ADVISORIES...None. && $$
Area Forecast Discussion
National Weather Service Springfield MO
505 PM CST Fri Feb 15 2019 .SHORT TERM...(This evening through Saturday Morning) Issued at 230 PM CST Fri Feb 15 2019 Winter precip event well underway with a moderate to heavy snow band roughly from the Truman Lake region east and southeastward through Lake of the Ozarks and into the Lebanon/Rolla region. 2-4 inches of snow has fallen in this region with an additional 1-2 inches possible before ending tonight. Storm total snow in that region will approach 6 inches in spots however will maintain Winter Weather Advisory for entire area. DOT reported snow covered roads with accidents in this region with temps around 20. Further south from Joplin to Springfield and Houston it has primarily been sleet and freezing rain with a few tenths of each so far. Expect this to continue into the evening hours. While temps have been in the middle 20s, enough solar insulation and likely roadway treatment has mitigated most impacts. However we are concerned that as we head further into the evening, more impacts will develop as higher traffic volumes begin and roads/ground have less impact from solar insulation. Therefore the main message this evening in this region is to expect slick roads for the evening commute. Locations south of US 60, along the Missouri/Arkansas border have remained at or slightly below freezing with mainly freezing rain. A few tenths of an inch of ice have accumulated, however some of this has melted due to solar insulation. Again, will need to watch this evening as refreeze is likely. This is all occuring as a shortwave trough moves through (its currently moving through east central KS) along with plenty of lift associated with a upper level jet streak. The warm nose (3C near 850mb as measured by 18Z sounding) has likely reached as far north as it will go given the 850mb low now moving into the area and additional cooling should develop aloft by evening across parts of the area. Latest runs of the RAP do indicate a batch of light to moderate precip moving through during the evening commute times from southwest to northeast through the area. We do lose cloud ice on the back edge of this and do expect some freezing drizzle as precip ends, but unsure as to how much qpf will remain. All precip will likely have exited the area close to midnight with low temps dropping into the teens across most of the area. .LONG TERM...(Saturday through Friday) Issued at 118 PM CST Fri Feb 15 2019 The region will see a rather active week of weather starting this weekend and through the end of next week. An enhancement noted on satellite this afternoon over the four corners region of the southwestern CONUS, will be the weather maker for Saturday afternoon. As this upper level feature moves into the plains, cyclogenesis will occur. This will allow a weak warm front to lift into the Ozarks during Saturday afternoon shifting surface winds out of the south. As the front slides north, slightly warmer temperatures will slide into the area during the afternoon. The warmer temperatures will likely remain along and south of I-44 with areas to the north of I-44 only climbing into the lower 30s. Temperatures in far southwest Missouri, McDonald County, may climb to around 41 degrees. As the southerly winds begin, precipitation will once again spread across the region. Short range models have been firm in limiting the amount of cloud ice that will occur as this system moves across the area. area from Truman Lake to Rolla and north may again see some light snow with some light freezing rain. However, areas south of that line will likely remain freezing rain/freezing drizzle. The bulk of the precipitation will spread across the area Saturday night into Sunday morning. With temperatures dropping into the upper 20s overnight, some accumulating freezing rain up to a tenth of an inch is expected. For areas from Truman Lake to Rolla and north up to a half inch of snow may fall along with the ice, depending on cloud ice. This system will shift east by lunch time Sunday as an upper level trough and surface high pressure move across the plains and the Ozarks. The region will be given a reprieve from Sunday afternoon through Tuesday morning when the next system moves into the Ozarks. Cold air will be in place as the midweek system spreads across the area. For far south central Missouri, precipitation be a cold rain and change over to snow Tuesday night but areas along and north of I-44 looks as though the precipitation will begin and remain snow. There may be a period right along the plateau where rain mixed with snow but overall current indications are for a dusting in south central Missouri to 2-3 inches across central and western Missouri. This system still have questions as to the duration and amounts, so theses snow amounts are very much subject to change. After the midweek system, a quick break occurs Wednesday night through Thursday before the next round of wintry precipitation potentially spreads across the Ozarks once again. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 457 PM CST Fri Feb 15 2019 MVFR and IFR conditions will persist through the period. System 1 currently producing a mix of wintry weather over the CWA, with FZDZ/FZRA/PL the predominant types at the terminals. Will gradually see the fzdz end from west to east as we head into mid evening. The second system will be on the heels of the first, moving in to the area during the afternoon Saturday and will keep the ceilings in MVFR/IFR. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...Winter Weather Advisory until midnight CST tonight for MOZ055>058-068>071-079>083-090>092-095>098-103>106. Winter Weather Advisory until 9 PM CST this evening for MOZ066- 067-077-078-088-089-093-094-101-102. KS...Winter Weather Advisory until 9 PM CST this evening for KSZ073- 097-101. && $$ SHORT TERM...Burchfield LONG TERM...Hatch AVIATION...Lindenberg