Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/05/17

Area Forecast Discussion
National Weather Service Gaylord MI
1010 PM EST Sat Feb 4 2017 .UPDATE... Issued at 1010 PM EST Sat Feb 4 2017 Synoptic snow has been rather slowly invading northern MI this evening. Antecedent dry air below 700mb (see 00z APX sounding, though some of the dry air had eroded by then), and a generally unimpressive system, account for this. However, significant lake enhancement has been evident on radar, both in individual elements moving ne-ward over northern Lake MI, and the broader tendency for better returns to hang back across the east half of upper MI. Upstream reports are supportive of western Mack Co already in the 2-4 inch range. Outside of eastern upper, vsbys (and thus snowfall intensity) have generally not tanked to any great deal, except over Beaver Isl and just recently at PLN. So lake enhancement to starting to be a bigger factor along the nw lower MI coast, as surface low moves from MN to Superior and 1000-850mb winds veer a bit. Will kick snowfall totals higher in eastern upper, especially Mack Co west of I-75, where 4-6 inch totals are reasonable. Will also push Emmet Co a touch higher, which is just enough to kick them into advisory territory. Rap runs have been consistently targeting them to see healthier see, especially with the 2nd batch of forcing which is now pushing into far nw WI and arrives here late in the overnight. No other major changes for now, though will be cautiously watching the rest of the nw lower coastal counties. && .NEAR TERM...(Tonight and Sunday) Issued at 331 PM EST Sat Feb 4 2017 High impact weather potential: More accumulating lake enhanced snows for primarily eastern upper. Some blowing snow. Pattern synopsis and forecast: Sfc high pressure was settled in over mid Atlantic states while a sfc low pressure/clipper resided in South Dakota. This clipper was associated with a shallow/weak mid level wave, possibly also tied to a positively tilted wave coming through Manitoba. DPVA, low level convergence and some right entrance region upper divergence was at play in helping develop some light snows across the Dakotas. There is also another weak mid level trough working across Wisconsin with low to mid level WAA being that primary forcing mechanism to produce another area of light snow. Across nrn Michigan, some of this WAA has taken it`s toll on the lake effect light snows/flurries from earlier this morning, with no snows or even low level clouds seen on satellite/area observations. Rather, just a thickening of mid and upper level clouds this afternoon. Highs have made it into the middle 20s to even a few lower 30s. Kind of a tricky forecast as there are some things at play that complicate matters. The first mid level trough and WAA spread across nrn Michigan through this evening bringing what could be the first of two rounds of synoptic light snows. Earlier data hinted at this first round of snow resulting in some dynamical cooling that would have resulted in the redevelopment of lake effect in SW flow regimes. This does not look as prolific, with only some very low end 12-13C delta t`s. Regardless, all data sets still suggesting re-energizing lake effect processes while the light synoptic snows overspread the north woods. There may be something of a break in the action, outside of the lake enhancement, until the second mid level trough arrives late this evening/overnight and beefs the lake response up again. This batch of forcing and deeper moisture slides by shortly after daybreak, and by the time all is said and done, still looking at 3-5 inches along the immediate NW lower lakeshore and eastern upper, with the higher amounts west of Interstate 75 in eastern upper. The advisory looks solid for eastern upper, but will continue to leave the NW lower counties out of any headline, as it may be confined to just the immediate lakeshore. Winds will be decently gusty coming off the lake too, so areas of blowing snow can be expected. The system cold front follows through morning, with H8 temps falling to -12C to -16C. While moisture is fairly scant, feeling pretty good about the development of light lake effect snows in NW flow regimes. Snowfall with this activity expected to be a half inch or less. Lows tonight not going very far, in the lower to middle 20s. Highs Super Bowl Sunday, in the middle 20s to lower 30s in downsloping areas of NE lower. && .SHORT TERM...(Sunday night through Tuesday) Issued at 331 PM EST Sat Feb 4 2017 ...More light snow Sunday night into Monday; stronger system arrives Tuesday... High Impact Weather Potential...A couple rounds of light snow are expected...the first Sunday night into Monday across the north and the second on Tuesday. Some freezing drizzle/rain will be possible Monday night into early Tuesday. Pattern Synopsis/Forecast...Low level northwest flow will back to southwest Sunday night as high pressure dives south of northern Michigan. This will bring an end to any lingering lake effect snow showers early Sunday night. A northwest-southeast oriented baroclinic zone then develops along a surface trough over northern MI early Monday morning, with snow overspreading eastern Upper and Tip of the Mitt before daybreak in response to WAA and frontogenetic forcing...with some additional support coming from the right entrance region of a 300mb jet streak. Only light amounts of snow expected from this activity with 1 to 2 inches possible across far northern Chippewa County. Forecast soundings show the column drying out somewhat above 800mb for the first half of Monday night, which will translate into a loss of ice in the clouds and hence the possibility of some freezing drizzle. Attention then shifts to the probable phasing of two systems over the Midwest Monday night into Tuesday. A digging northern stream shortwave will quickly move from the Pacific Northwest into the Upper Midwest during this timeframe while a southern stream shortwave lifts from the Central Plains into the Great Lakes region. At the surface, this will translate into a rapidly deepening low that will track from northern IL Tuesday morning through the Thumb by Tuesday evening. Max wet bulb temps from 0-3km will start to rise Monday night from south to north, with our southern two tiers of counties ranging from 1 to 3C by 12Z Tues. The initial lack of ice early Tuesday morning will spell a chance of freezing drizzle/rain as precip with this system overspreads the area. But once the column saturates aloft around daybreak Tuesday, expect the precip to transition over to snow across most of the area. Forecast soundings show only a slight warm nose aloft, so at this time am not sold on much in the way of sleet or freezing rain during the day across our south. The potential for a wintry mix is there for our south, but its looking like more of a transition to mainly snow across the north and rain across our far south (where temps will climb into the mid 30s). Snowfall amounts on Tuesday will generally range from 1 to 3 inches mainly north of M-72. Wind not expected to be an issue on Tuesday, as the pressure gradient will not be too strong with the center of the low passing just to our south. Primary Forecast Concerns...First, there is some question as to how long Monday`s snow will linger over the northern half of the forecast area. The NAM/CMC remain the progressive solutions, carrying the best forcing east of the area by early afternoon. On the other hand, the GFS/ECMWF are much slower to lift the best forcing northeast of the area, with light snow lingering into the evening across eastern Upper. Being 2 to 3 days out from Tuesday`s system, general model consensus is decent enough for handling this outside-climatological-norms (MSLP +2 to 3 sigma) system. However, there is still considerable spread in the possible track between deterministic models as well as the GEFS, CMCE, and ECWMF ensemble members. The GFS and ECMWF push warmer 850mb temperatures (0C or warmer) all the way to the Straits, while the NAM and CMC are a tad colder. Of course, this will have ptype ramifications and will need to be pinned down by upcoming shifts. .LONG TERM...(Tuesday night through Saturday) Issued at 331 PM EST Sat Feb 4 2017 After a prolonged period of well above normal temperatures, there looks to be a pattern change taking shape through the extended period. Temperatures will still be above normal going into mid-week, but the broad riding setup across much of the southern CONUS will begin to shift westward as height falls work their way from the northern Plains and through the Ohio Valley. By the end of the extended period, there will be noticeable troughing through the Great Lakes and into the Tennessee Valley, with amplified ridging spanning from the desert SW through the Great Plains. This should help to get temperatures back into more normal ranges as we go into the weekend. With shortwaves moving through the pattern, wouldn`t be surprised to see some scattered to isolated showers through the week but nothing that looks to be producing large amounts at this time. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 702 PM EST Sat Feb 4 2017 Snow slowly advancing into northern MI this evening, ahead of low pressure in MN. Transition to IFR conditions expected to occur shortly at PLN/TVC/MBL, later on at APN. Snow will be less heavy/briefer at APN, due to lack of enhancement from Lake MI. Duration will be lengthier near Lake MI, with one wave of snow this evening and another late tonight. Snow-liquid ratios around 16-1 are expected. Improvement to MVFR and then VFR expected during the day Sunday. Ongoing south winds will veer sw tonight, and nw Sunday afternoon, remaining somewhat brisk throughout. && .MARINE... Issued at 331 PM EST Sat Feb 4 2017 Gusty SW winds may tap low end gale force along the Lake Michigan shoreline, especially through the Manitou Islands this evening. Have opted to just mention isolated gales in the forecast rather than issue a Gale Warning. These wind swing around out of the W/NW late tonight into Sunday behind an area of low pressure and cold front. SCA conditions continue Sunday/Sunday evening. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY until 7 AM EST Sunday for MIZ008-015. LH...SMALL CRAFT ADVISORY until 6 PM EST Sunday for LHZ345>349. LM...SMALL CRAFT ADVISORY until 6 PM EST Sunday for LMZ323-341-342- 344>346. LS...NONE. && $$ UPDATE...JZ NEAR TERM...SMD SHORT TERM...MEK LONG TERM...ALM AVIATION...JZ MARINE...SMD
Area Forecast Discussion
National Weather Service Columbia SC
1054 PM EST Sat Feb 4 2017 .SYNOPSIS... A cold high pressure center will move off the Virginia and North Carolina coast tonight. Pressure ridging will extend along the Gulf Coast Sunday and Monday. An approaching cold front Tuesday will move into the forecast area Tuesday night or Wednesday. Air mass modification and the southerly flow ahead of the cold front will bring warmer weather. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Surface high pressure in the mid-Atlantic will move offshore tonight allowing moisture to spread steadily inland in the form of low clouds. Mostly clear skies across the central and northern Midlands earlier tonight has allowed temperatures to drop below freezing. How far northwest the stratocumulus will push is uncertain. In addition, models suggest increasing mid- level clouds early Sunday morning as a mid-level trough approaches. These trends in cloud cover may mean the central Midlands has already reached its low for the night as net radiational cooling is hindered. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... Weak surface high pressure will move off the coast Sunday. A deep westerly flow from the surface to aloft develops with increasing thickness values. This will lead to a warming trend with highs in the upper 50s and lower 60s for Sunday. Surface high pressure over the upper Midwest will bridge with a suppressed high along the Gulf Coast states providing dry conditions Sunday night. Another cold night expected Sunday night with lows in the 30s although increasing clouds may impact overnight lows and will provide a gradient in temps with warmer values in the CSRA and southeastern Midlands. Sunday will be slightly warmer than today as the air mass modifies and surface high weakens. && .LONG TERM /MONDAY THROUGH SATURDAY/... Progressive 500 mb upper flow pattern expected through the extended forecast period leading to fast moving disturbances across the region with lower than normal confidence in timing. Broad surface low development will occur over the northern Plains while the surface ridge over the forecast area shifts offshore and the Gulf of Mexico opens to southerly flow. This will allow moisture to increase across the area again with precipitable water values pushing over an inch by Monday evening. Isentropic lift also increases late Monday and Monday night as warm advection develops to our west and shifts over the area Monday evening and continues into Tuesday as the surface low deepens as it moves into the Great Lakes region. A positively tilted digging upper trough will drive a cold front through the forecast area Wednesday. Will carry gradually increasing pops across the region Monday night through Tuesday with the highest pops mainly Tuesday night ahead of the front. Surface high pressure will build over the region behind the front Wednesday night and remain over the forecast area Thursday providing dry weather. Reasonable agreement from the medium-range models showing a fast moving clipper system diving through the western Ohio Valley Thursday and crossing the forecast area Thursday night into early Friday. Moisture may be limited with this system but temperatures may be cold enough to support a few flurries especially across the northern counties. However, this scenario is not a favorable one for accumulating precipitation. Temperatures through the period will be above normal through Wednesday, near normal Thursday, below normal Friday, then back above normal by the weekend. && .AVIATION /04Z SUNDAY THROUGH THURSDAY/... A dry high pressure center will move off the Virginia and North Carolina coast tonight. The high will maintain dry conditions and VFR conditions at the terminals through most of tonight. As the high shifts eastward an onshore flow will bring increased moisture into the forecast area late. The near-surface layer should remain too dry for fog. However, most of the guidance indicated a VFR ceiling developing before 12z. Some of the guidance such as the NAM MOS had MVFR ceilings developing mainly at the southern and eastern terminals. This may be correct because satellite displayed moisture not far to the southeast across southern Georgia and near the South Carolina Coast. The HRRR displayed MVFR ceilings remaining south and east of the terminals. Based on the initial dryness and model forecast of little isentropic lift and h85 westerly flow we leaned toward the more optimistic guidance. Followed the NAM and GFS MOS for the wind forecast with wind light and variable tonight and west-southwest near 10 knots Sunday. EXTENDED AVIATION OUTLOOK...Restrictions possible Monday night through early Wednesday. Strong/gusty winds possible Tuesday night into Wednesday as a cold front crosses the region. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
Area Forecast Discussion
National Weather Service Grand Forks ND
931 PM CST Sat Feb 4 2017 .UPDATE... Issued at 928 PM CST Sat Feb 4 2017 Light snow has diminished over southeastern zones and will be removing POPs after 04Z. Clearing over the northeast is resulting in latest HRRR guidance dropping overnight lows to near 10 below across Towner County, which seems reasonable given the lightest winds across the CWA. Will adjust temps per latest hi-res model guidance and find tune sky cover grids for clearing ahead of more clouds cover coming from upstream, per latest 3.9 micron imagery. UPDATE Issued at 648 PM CST Sat Feb 4 2017 Skies are clearing over the northwest and snow has pushed just east of the valley. The clearing will be filled back in by the late evening hours as more mid clouds move into northwest ND from eastern MT. Have adjusted sky/POP grids accordingly. && .SHORT TERM...(This evening through Sunday) Issued at 314 PM CST Sat Feb 4 2017 Next short wave which was not advertised too well is moving into eastern ND at mid aftn. Area of snow with this feature moving quickly east likely producing 1 inch or less of snow. Did up pops for this feature. After this system a break as colder air moves back south later tonight into Sunday morning. Next system to spread some light snow into DVL basin Sunday aftn. 120kt 300 mb jet in place so systems are moving quite fast. .LONG TERM...(Sunday night through Saturday) Issued at 314 PM CST Sat Feb 4 2017 Main concern throughout the period will be the winter storm potential with the late Monday night/Tuesday system and associated impacts. Yet another shortwave embedded in the relatively zonal upper flow will keep light snow chances lingering across northern portions of the area Sunday night and into early Monday. The strongest forcing and associated area of precipitation continues to be generally along the international border with maybe an inch or two of accumulation. The region should then see a brief break for the daytime hours on Monday as low pressure begins to organize east of the Rockies. Models continue to be in pretty good agreement with the late Monday night/Tuesday system with the main low pressure center situated near the Iowa/Missouri border by 06z Tuesday. As this system deepens and propagates towards the lower Great Lakes, the main inverted trough axis will slowly shift from west to east across the region. A broad area of accumulating snow looks likely with some fine tuning still needed to amounts. GEFS plumes continue to show a fairly large range of possibilities regarding QPF but have generally been pretty consistent with the highest amounts across the north. Lastly, as the low deepens and high pressure noses into the western Dakotas behind it, a fairly tight pressure gradient will persist across the region. Although winds don`t look to be incredibly strong for a long period of time, there should be enough to blow things around, both while snow is falling and possibly for a time after the heaviest snow has ended. Colder air will then return as surface high pressure briefly builds in midweek. Temperatures look to struggle to get above zero on Wednesday with wind chills dropping back into the -30s during the nighttime and early morning hours. The cold blast will be short lived, however, as 850 mb temperatures look to warm to above zero by the end of the work week. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 648 PM CST Sat Feb 4 2017 Clearing skies over northeast ND prompted early amendment to GFK/DVL as cleaning came across the area quicker than expected. VFR deck will fill area back in later this evening. MVFR shall improve across southern valley and northwest/west central MN as well, so expect more AMDs expediting this over the next couple of hours. Models too aggressive holding on to MVFR throughout the night, so hopefully 00Z runs will have a better handle on latest trends. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Speicher SHORT TERM...Riddle LONG TERM...Lee AVIATION...Speicher
Area Forecast Discussion
National Weather Service Lincoln IL
905 PM CST Sat Feb 4 2017 .UPDATE... Issued at 905 PM CST Sat Feb 4 2017 A band of mid clouds associated with the approach of a weak trough will continue to quickly advance across central and eastern Illinois this evening. The back edge of the clouds has already reached near the I-55 corridor as of 9 pm. Timing tools show the clearing should reach the Indiana border toward midnight. Have updated the sky grids to account for this faster clearing. The surface trough passage will lag the clouds by 8 to 10 hours per the latest HRRR and RAP output. That will delay the wind shift from south winds to west winds until later tonight. Winds in a few areas have remained gusty as the cloud band has worked its way eastward, but additional weakening should develop the rest of the night as the trough nears the area. With weakening winds expected later tonight under clear skies, have trimmed a degree or two from forecast lows since we are only 3-4 degrees above those numbers already this evening, in some areas. Looking at a sunny and pleasant day to finish out the weekend, with warmer temps than Saturday. Updated forecast info will be available shortly. && .SHORT TERM...(This evening through Sunday) ISSUED AT 247 PM CST Sat Feb 4 2017 Brisk southerly winds will continue into this evening as the pressure gradient between a high over West Virginia and a low tracking across South Dakota remains tight. The gradient will relax later tonight as a trailing surface trough approaches from the west, leading to decreasing winds overnight. Skies will initially be overcast: however, a rapid clearing trend will be noted from west to east across the area this evening. Based on satellite timing tools, think the entire KILX CWA will be clear by midnight. Due to southwesterly flow, overnight lows will be several degrees warmer than last night...with readings remaining in the upper 20s and lower 30s. Once the trough passes, light W/NW winds will be noted on Sunday, which should act to mitigate the warming trend. Despite full sunshine, have gone a couple degrees below guidance for highs...with afternoon temps mainly in the lower to middle 40s. .LONG TERM...(Sunday night through Saturday) ISSUED AT 247 PM CST Sat Feb 4 2017 High pressure ridging will move off to the east Sunday night and allow southerly winds to return to the area and bring waa and moisture advection back into the CWA, just ahead of the next system coming in for the beginning of the work week. The models continue to differ on the timing of the start of the precip in the area Monday, but consensus is that the chance of precip will begin Mon afternoon and then quickly increase for Monday night. Though the mid level flow remains fast zonal, the surface low begins to deepen just west of the area Monday night and continues this trend into Tuesday. The associated cold front with this system will quickly move through the CWA either Monday morning or afternoon...depending on which model is looked at. Showers and possible thunderstorms should develop ahead of this front in the warm sector, beginning Monday night. SPC Day 3 outlook suggests a marginal risk of severe weather in southern IL, that does include most of southeast IL, but remains south of a Taylorville to Paris line. The main threat would be Monday night and just be hail due to the steep lapse rates forecast by both the GFS and NAM during this time period. As the system deepens, the threat of storms will shift north for Tue morning and include the entire CWA...based on the instability parameters in the models. This area of convection will begin to shift east as the front moves through the state. Again, SPC is indicating the possibility of some severe storms on Tue, but mainly in the TN and OH valley areas due to the timing of best instability during the day just ahead of the front. The only area that could see some severe storms early in the day would be in southeast IL before the front moves through. So, have thunder mentioned in the forecast for Monday night over the whole area, and then Tuesday in the east and southeast. After this system passes the area and the low pressure area moves off into the Great Lakes region, wrap around moisture will advect into the area, but only in the northern parts of the CWA. Pops across this area will mostly be in the slight chance range, which will not get mentioned in the worded forecast this afternoon. Cooler and dry weather will then follow this system through Wednesday night as a high pressure builds into the area for the middle of the week. Some of the ensemble models are trying to bring precip/light snow into the area Thursday, but given that a large high pressure area should be over us, think the chance of precip is going to be will not see any precip mentioned in the forecast for Thur. This dry weather will continue through Friday evening as this high pressure settles into the southeastern US Friday. Models then having issues with trying to bring more precip in for Friday night and Sat. This seems unlikely as the next weather producer should be north of the area, but given this is 7 days out, will let the ensemble forecast ride for now; it will likely change a few more times before then anyway. Temps will get quite warm for Monday and Tue ahead of the next weather system, then cooler for Wed and Thur, quickly followed by warmer temps for Fri and Sat. Given the fast zonal flow pattern we are currently in, these type of temp swings are not uncommon. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 600 PM CST Sat Feb 4 2017 There is a high likelihood that VFR conditions will prevail through the entire 00z TAF period. A weak disturbance will continue to bring low VFR clouds to the central Illinois terminals early this evening. Latest HRRR suggests the potential for MVFR ceilings as the back edge of the clouds progresses across Illinois. However, no MVFR ceilings currently exist upstream across eastern Iowa/Missouri into western Illinois. Based primarily on satellite timing tools...have lowered ceilings to 5000ft for this evening. After appears the clouds will depart from west to east across the area by mid to late evening, with mostly clear conditions expected overnight into Sunday morning. Winds will initially be quite strong from the south this evening...with occasional gusts to 25kt. Winds will gradually veer to the west and and remain 10-15kt later tonight, as a trough of low pressure approaches from the Plains. Winds will veer to the NW later Sunday morning with speeds holding in the 10-15kt range. Little in the way of cloud cover is expected on Sunday. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Shimon SHORT TERM...Barnes LONG TERM...Auten AVIATION...Shimon
Area Forecast Discussion
National Weather Service Jackson MS
912 PM CST Sat Feb 4 2017 .UPDATE... Updated for evening discussion. && .DISCUSSION... Clouds continue to increase late this evening, with some light rain falling across portions of the northwest. Expect chances for light rain later tonight across much of the area, with low temps in the 40s. The only change to the current forecast was to adjust pops for this evening based on latest HRRR and radar trends. /27/ Prior discussion below: Tonight and Sunday...Cloud cover to the west has been slow to make much progress east today due to the substantial dry airmass in place. Still, continued isentropic ascent will eventually win out and provide enough moisture/warm air advection for some light precipitation to break out over northern portions by midnight and increase southward toward dawn. Though baroclinic setup north of the LA/MS coastal frontal boundary looks sufficient for isentropic ascent Sunday, relatively weak wind fields in the saturated layer looks to only support a light rain/shower event. This is seen readily in the HRRR reflectivity guidance and with the light QPF in the GFS and NAM. Temps overnight will not be as cool as last night due the increased cloud cover, however, boundary layer cooling from the introduction of moisture should be sufficient to cool most areas back at least into the 40s. As the warm front moves northward Sunday, maximums in the 60s look possible over the southern half where otherwise a cool day (as will be the case in the north) would have been in store./26/ Sunday Night through Saturday...For the start to the new work week, focus will be on a sequence of shortwaves moving eastward across the country and the chances for severe weather that may accompany them. Sunday night into Monday, showers with perhaps a few rumbles of thunder will be focused primarily along a lifting warm front in the northern portions of our forecast area. Expect temperatures to warm into the low to mid 70s during the day Monday with continued southerly flow at the surface. Chances for thunderstorms will gradually increase across the region throughout the day and into Monday night ahead of the first approaching shortwave. Modest mid- level height falls should spread eastward into the overnight hours, while at the surface a low deepens and lifts from the central High Plains toward the Midwest. Instability will increase along a corridor just west of the forecast area as warm, moist air is drawn northward Monday night. Most thunderstorm activity late Monday night should therefore be confined to parts of Arkansas and far northern MS/western TN. Model guidance presents a slightly faster scenario with this first wave than was apparent over the last few cycles, but the consensus still indicates a window of opportunity for severe thunderstorms to develop in our forecast area on Tuesday. A faster timing for this shortwave would limit the peak heating and instability available to storms firing earlier in the day Tuesday, while a slower wave passage would keep storms capped until greater instability could be achieved. MLCAPE values between 500 to 1000 J/kg are expected during the day, with 50-60 kts of 0-6 km shear helping to organize and sustain updrafts. Mid-level lapse rates near 7 to 8 C/km early in the day will be tempered somewhat with weak height rises and warming on the backside of the shortwave by the afternoon. 0-1 km shear of 25-35 kts and SRH of 200-300 m2/s2 suggests a possible threat for tornadoes, particularly if storms are ongoing early Tuesday morning when LCL heights are lower. Increasing LCL heights instability with daytime heating suggests more of a hail and damaging wind threat during the afternoon hours. Will keep mention of a Limited severe and tornado threat in the Hazardous Weather Outlook for an area along and north of Interstate 20 Tuesday into Tuesday night. A cold front will push into the forecast area by Tuesday night, bringing drier air and an end to shower and storm chances from north to south. Showers may linger across southern portions of the forecast area into Wednesday, but the remainder of the week should be dry. It looks like moisture will be limited before another quick moving shortwave slides across the country Thursday into Friday, but its passage should keep temperatures from warming too far above normal by the end of the week. /NF/ && .AVIATION... 00Z TAF discussion: VFR conditions were observed at all TAF sites at 2330Z but cloud cover wl cont to increase from the west with a gradual lowering of cigs. Cigs will lower to MVFR at most locations between 06Z and 09Z, with HBG remaining VFR. Some -shra will begin spreading in vcty of the TAF locations after 06Z with -ra expected to cont through Sun. Cigs wl remain MVFR over the se Sun but lower to IFR category elsewhere by 17Z and cont Sun aftn. /22/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 44 64 54 76 / 36 53 47 12 Meridian 42 59 51 75 / 29 50 48 16 Vicksburg 45 65 56 75 / 40 50 47 13 Hattiesburg 44 67 54 77 / 10 35 20 11 Natchez 48 67 58 76 / 32 50 28 11 Greenville 43 57 52 71 / 49 58 65 24 Greenwood 42 60 52 72 / 50 57 68 26 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$
National Weather Service Jackson KY
1055 PM EST Sat Feb 4 2017 .UPDATE... Issued at 1055 PM EST SAT FEB 4 2017 Based on the latest HRRR and some virga returns showing up on radar with more to the southwest have updated the PoPs and Wx grids to allow for more drizzle and freezing drizzle deeper into the CWA through dawn. Also adjusted temperatures through the rest of the night not expecting much more drop off with a mid level deck of fairly thick clouds in place. Accordingly, have updated the ZFP to adjust for the Wx and T changes for the remainder of the night. The grids have been sent to the NDFD and web servers. UPDATE Issued at 745 PM EST SAT FEB 4 2017 00z sfc analysis shows high pressure off to the east of the state with low pressure moving into the Central Plains. This has set up good conditions for a ridge to valley temperature split this evening and we can see that showing up in the latest obs as upper 20s are noted in the eastern valleys while mid 30s exist on the ridges. Winds have swung to the southeast but remain light. Meanwhile, dewpoints are still quite dry mainly in the single digits and teens. Passing high clouds will not slow the temperature difference this evening - and not until lower clouds arrive in the early morning hours are they expected to mix out. This is also the time frame for any potential freezing drizzle - mainly south of the Mountain Parkway - as supported by the latest HRRR. Will continue to monitor this concern going forward, but for this update have just made adjustments to the near term grids to account for the latest obs and trends. These have been sent to the NDFD and web servers. && .SHORT TERM...(This evening through Sunday night) Issued at 313 PM EST SAT FEB 4 2017 Cirrus continues to stream in north of Mountain Parkway this afternoon ahead of a subtle upper level trough moving across the upper Midwest into the western Great Lakes. Surface high pressure will slide east into the mid-Atlantic, allowing winds to veer south/southwesterly through tonight, maintaining a warming trend. While temperatures will top out in the mid-upper 30s north of the Interstate 64 corridor this afternoon, the western fringe of the aforementioned surface ridge will likely hold influence long enough for at least the more sheltered valleys of far eastern Kentucky to decouple preceding a period of increasing winds/lowering clouds this evening/tonight. This will set the stage for a period of below freezing temperatures tonight into early Sunday morning before warm air advection brings all of eastern Kentucky above freezing within an hour or two after sunrise. A layer of saturation just off the deck to about 850 mb near the 0C isotherm will lead to patchy freezing and liquid drizzle late tonight into Sunday morning, with all freezing drizzle expected to end by mid morning. Not expecting any measurable precipitation given this shallow saturation and rising heights aloft taking place by early morning with passage of the anemic trough axis. However, a light glaze will be possible in areas that do receive freezing drizzle. Southwest winds will become gusty later Sunday morning through the afternoon as a surface low deepens across Ontario and Quebec. Continuing warm air advection will warm temperatures further, although lingering low clouds should limit highs to the mid-upper 40s in the Bluegrass and generally upper 40s to lower 50s across the remainder of eastern Kentucky. Weak shortwave ridging will keep the warm air advection regime in play Sunday night while weak surface ridging provides for a subtle ridge/valley temperature split with valleys dropping into the low-mid 30s while ridges remain closer to the mid 30s. .LONG TERM...(Monday through Saturday) Issued at 313 PM EST SAT FEB 4 2017 Period will begin with surface high pressure parked along and near the Mid Atlantic Coast, with SW flow kicking in on the back side. Meanwhile a front will stall out along and near the Ohio River and this will interact with gulf moisture to bring overrunning precip to the region through the afternoon on Monday. That said, thought the model consensus seemed reasonable keeping the best chances along and north of the Mountain Parkway. A deeper long wave trough across the central US will eject east and deepen a surface low across the northern Ohio Valley and Great Lakes. The trailing cold front will be the lifting feature of concern here in eastern KY Tuesday into Tuesday night. Some of the mass fields in the various guidance products govern some differences in relation to timing and evolution, and did lean to the blend for this period. Even so did feel categorical POPs were not out of the question and therefore made some adjustments in that direction. The guidance does continue to pick up on some modest instability Tuesday afternoon and evening with 300 to 400 J/kg of MUCAPE. Also the wind fields remain strong with 850mb jet approaching 70 knots and part of this wind energy could be mixed down along the front and with any showers and thunderstorms that develop. Therefore main threat with the storms at this stage of the forecast process will be strong gusty winds. The issues mentioned before about timing/evolution differences will continue to present additional problems with guidance in the remainder of the long term period. This is leading to overall less confidence with regards to increasingly amplified trough that digs into the SE US by Thursday into Friday. There have been wholesale differences from run to run with embedded shortwave that quickly moves SE out of the Pacific NW. The blend is all over the place given the uncertainty and introduces ribbons of POPs with each guidance idea. Given the lack of return flow seen having a difficult time buying into the QPF suggested by the GFS/Canadian. Right now leaning to the 12Z ECMWF solution which is dry and therefore would be more in line with the lack of return flow and increasing subsidence. The pattern presents us with another system by next weekend and for now will leave as is with relation to blended POPs. This period we will be presented with more a roller coaster effect temperature wise. That said, the temperatures climb into the low to mid 60s for highs by Tuesday and in the wake of a a cold front temperatures drop into the upper 30s to lower 40s for highs Thursday. The high amplitude trough will move east quickly and return flow will bring high temperatures right back into the upper 50s by next Saturday. Coldest nights will be Wednesday and Thursday night with potential for a temp split if clouds clear. At this point, will keep blends temps with uncertainty on clouds. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) ISSUED AT 720 PM EST SAT FEB 4 2017 VFR conditions to continue through this evening and most of tonight ahead of a period of top-down moistening. Mid level ceilings will be on the increase this evening, further lowering to MVFR criteria around daybreak Sunday morning. Patchy freezing drizzle will be possible early Sunday morning, although no more than spots of light glazes are in the offing. Nonetheless, a small potential for slick spots on area runways will exist prior to temperatures quickly warming above freezing at all terminals within an hour or two after sunrise. MVFR ceilings will likely remain in place through 00Z Monday while southwest winds increase toward 10 knots - becoming gusty Sunday afternoon. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...GUSEMAN LONG TERM...DJ AVIATION...GREIF
Area Forecast Discussion
National Weather Service Memphis TN
834 PM CST Sat Feb 4 2017 .DISCUSSION...Water Vapor satellite trends this evening indicate a subtle but weak 700 mb shortwave trough moving through the Lower Mississippi Valley this evening. This has resulted in the development of rain showers across much of the area into the evening hours. KNQA WSR-88D radar trends show most of the rain showers have shifted south to areas mainly south of I-40. Latest 00Z WRF and HRRR suggest this activity will gradually shift southeast overnight into Sunday morning. Will make some adjustments to rain chances for the remainder of tonight and adjust any other elements as needed to account for short term trends. CJC && .PREV DISCUSSION... /issued 520 PM CST Sat Feb 4 2017/ UPDATE... Updated to include the 00z aviation discussion. PREV DISCUSSION... /issued 302 PM CST Sat Feb 4 2017/ DISCUSSION... Clouds are quickly invading the Mid-South from the west this afternoon. This has hindered temperatures from getting out of the 40s across portions of Northeast Arkansas. Winds have turned around to the south this afternoon as surface high pressure has shifted east. Expect low temperatures to occur this evening and hold nearly steady overnight thanks to the cloud cover and warm air advection. Also, expect some light showers to begin developing generally along and south of Interstate 40 thanks to the warm air advection. Shower activity should diminish during the morning hours. Although, portions of North Mississippi may continue to see small chances for light showers throughout the day as a secondary warm front moves into Central Mississippi. Clouds should clear over northern portions of the area while conditions will remain mostly cloudy over North Mississippi. Expect highs in the mid to upper 50s. The secondary warm front will move northward Sunday Night through most of the Mid-South. Chances for showers and a few embedded thunderstorms will increase across the area. Lows Sunday Night will likely occur in the evening as well as temperatures will warm behind the front. The warm front should clear the Mid-South by mid-day Monday. Expect clouds may scatter out behind the front which may help highs get into the lower 70s across portions of the area. Dewpoints will also climb to around 60 degrees. An upper trof will begin to move into the Mid-South Monday Night ahead of a developing low pressure system over Kansas. Models are a tad further north with the track of the low pressure system and a little weaker with the strength of the upper trof. Showers and thunderstorms will begin to spread into the Mid-South late Monday Night into Tuesday. Can`t rule out a few severe storms developing, but the threat doesn`t look as high as it did 24 hours ago. Most of the shower and thunderstorm activity will be east of the CWA before the trailing cold front even enters the CWA. Thus expect temperatures to possibly warm into the lower to mid 70s behind the convection Tuesday afternoon. The cold front will move through the Mid-South Tuesday Night. Can`t rule out an isolated shower developing along the front. Otherwise, cooler temperatures will begin filtering into the area. The GFS continues to be consistent on the 12Z runs of bringing another upper trof into the region late Wednesday Night into Thursday. With colder air in place, any precipitation that develops with the trof will fall as snow. Have added 20 POPS back into the forecast for northern areas of the Mid-South. High pressure will settle over the area on Friday. The high will quickly shift east allowing winds to turn around to the south by Friday Night. Another cold front will begin to approach the Mid-South on Saturday. Have introduced a 20 POP for light showers that may develop ahead of the front. Highs will back into the 60s. KRM && .AVIATION... /00z TAFs/ Scattered, light rain showers will continue across the Mid-South this evening, eventually shifting south of I-40 by 06z. Ceilings are currently between 4000-6000 ft and are forecast to gradually lower to around 1500-2000 ft by 09-10z. Ceilings are expected to improve during the mid/late morning hours along/north of I-40 but are expected to lower further to IFR category at KTUP. Winds will be from a general south to southwest direction, generally under 8 kts. Johnson && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
905 PM EST Sat Feb 4 2017 .SYNOPSIS... High pressure centered over the area will shift off the coast tonight and Sunday as a trough of low pressure develops along the Carolina coast. A weak cold front will move through Sunday night. A stronger frontal system will move through the area Wednesday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... As of 905 PM Saturday...High pressure will gradually shift off the coast overnight with a coastal trough developing along the SE coast near the Gulf Stream. The coastal trough may briefly move inland along the immediate NC coast late tonight/early Sunday before moving offshore later Sunday. Clear skies and light winds this evening have allowed temperatures to quickly fall into the mid and upper 20s both inland and along the north coast. The models continue to show increasing clouds with patchy light WAA rain moving in off the waters late tonight into Sunday morning in response to convergence along the coastal trough as well as a weak upper level disturbance moving through the flow aloft. The best chances of precip will be along the coast near the trough after midnight but several models /especially the higher resolution models/ are indicating light qpf pushing inland across much of eastern NC as well. Latest 00Z MHX sounding indicates very dry air below 500 MB and this could impede the inland penetration of moisture. Indeed the 00Z HRRR has backed off on precipitation occurring over the coastal plain and develops it all east of Highway 17. The 12Z ECMWF and 12/18Z GFS models were also dry. The wettest models inland were the CMC and NAM. The main forecast concern overnight remains the threat of light freezing rain/freezing drizzle across inland areas as temperatures, while are expected to gradually increase after midnight in response to increasing cloud cover, could remain at or below freezing deep inland as much of the guidance is indicating this through around 12z. The most challenging part of the forecast is just how much precip reaches inland areas as it will have to overcome a very dry airmass in place before the column becomes saturated. Will follow a blend of guidance for PoPs which gives slight chance across the inland tier to chance near the sounds and coast late tonight. The moisture remains shallow, mainly below 800 mb, with most of the saturated profile above freezing so only expect light precip to fall, and to fall as liquid, but if the surfaces are below freezing a light glaze could develop. The main impacts will be the potential for icing on bridges and overpasses making for hazardous driving conditions. We have issued a SPS to address this as confidence remains low as whether precipitation develops where the coldest surface temperatures are expected overnight. Expect a non- diurnal temp curve overnight, with lows dropping into the mid to upper 20s by midnight, then becoming steady or slowly rising after 06Z with increasing cloud cover. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... As of 2 PM Saturday...A weak area of low pressure will develop off the Southeast coast along the coastal trough and lift NE across the offshore waters Sunday. Precip chances continue in the morning but move offshore during the afternoon with skies clearing from west to east. The freezing rain/drizzle threat should end quickly, by 9 am at the latest, with temperatures rising into the low to mid 50s during the afternoon. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... As of 250 AM Saturday, A warming trend will develop through midweek, before a strong cold front brings a threat of rain and much cooler temperatures for the end of next week. Sunday night through Tuesday Night...high pressure will set up shop along the NC/VA coast Monday before moving offshore Tuesday. This will lead to increased southwest winds, especially later Tuesday into Tuesday night. This will enhance the warm advection driving high temperatures into the upper 50s to lower 60s Monday, then into the lower 70s inland with low/mid 60s Outer Banks on Tuesday. Wednesday through Friday...Trends over the past several runs of the Medium-Range models has been faster with the strong cold front and association area of precipitation Wednesday. It now appears the rain will begin early in the day and mostly be offshore during Wednesday afternoon. Strong gusty Southwest winds with keep low temperatures in the mild 50s with highs again into the lower 70s away from the water Wednesday. Given the quick movement of the system, rainfall amounts will be limited to one- quarter inch or less. Rapid clearing is likely for Wednesday night as dewpoints crash, dropping from the 50s to the 20s by Thursday morning. High temperatures for Thursday will be some 20 degrees colder across the CWA. Strong high pressure will build down the east coast into Friday. The GFS has trended much drier for Friday, versus the 00Z run from yesterday, while the ECMWF builds strong high pressure down the coast. Will continue dry trends through late week with below normal temperatures expected through Friday. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Short Term /through Sunday/... As of 620 PM Saturday...High confidence in VFR conditions through 06Z with to mostly clear skies. Clouds then increase after midnight with MVFR conditions mainly in ceilings developing late tonight into Sunday morning. A few showers may move inland from the coast and there is a slight chance of light freezing rain or freezing drizzle at the terminals from around 06-14z Sunday but confidence is low at this time and will not mention in the TAFs. The moisture quickly move offshore Sunday afternoon with skies clearing and VFR conditions returning by 18Z. Long Term /Sunday night through Wednesday/... As of 3 AM Saturday, VFR conditions should prevail through much of the period. High pressure and fairly low dewpoints should keep VFR conditions in place through Tuesday. Periods of MVFR ceilings will be possible as a strong cold front crosses the area Wednesday with areas of showers expected. && .MARINE... Short Term /through Sunday/... As of 905 PM Saturday...High pressure building in from the west is allowing the winds and seas to diminish across the waters this evening. N/NE winds 10-15 kt this evening will shift to E overnight. A coastal trough will move into the southern and central waters late tonight with winds becoming SE around 15-20 kt east of the trough. A weak low will lift NE along the trough Sunday with winds across the waters becoming W to NW around 10-15 kt. Seas around 3-5 ft across the waters early this evening are expected to subside to 2-4 ft after midnight and continue in this range through Sunday. Long Term /Sunday night through Wednesday/... As of 3 AM Saturday, low pressure will pass east of the area on Sunday night with west winds around 5-15 knots and seas at 3-5 ft. Some gusts to 20 knots will be possible Sunday night before subsiding to 5-15 knots again Monday from the WNW/NW. No advisories are expected on area waters until Tuesday night and Wednesday as strong gusty SW winds develop ahead of a strong Canadian cold front. Gale force winds appears likely starting late Tuesday night with sustained winds to near 35 knots with seas building to as high as 8 to 9 feet, especially over the central waters. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...Small Craft Advisory until 10 PM EST this evening for AMZ152- 154. && $$ SYNOPSIS...SK/CQD NEAR TERM...SK SHORT TERM...SK LONG TERM...CTC AVIATION...CTC/SK MARINE...CTC/SK
Area Forecast Discussion...CORRECTED
National Weather Service Reno NV
323 PM PST Sat Feb 4 2017 .SYNOPSIS... A series of storms will impact the region this coming week with a mix of wind, snow, and heavy rainfall. The first storm Sunday night into Monday will bring strong winds areawide along with mountain snow. A second storm Tuesday into Wednesday is likely to bring heavy mountain rainfall and a risk for flooding of streams and poor drainage areas. A third storm Thursday into Friday doesn`t appear as strong but could bring more rain and snow to the region. && .SHORT TERM (until daybreak Tuesday)... * Strong ridgetop winds have been more persistent today than expected. Sierra Crest sensors still hitting gusts over 100 mph with "more reasonable" 60 mph gusts on W Nevada ridgetop sites. 700mb flow really isn`t that strong so not sure what is going on here. 19z HRRR trends suggest that these strong ridge winds would continue into the evening before diminishing some overnight. * General lull in precipitation through Sunday afternoon as ridging works into the area. Just a few upslope showers near Tahoe right now but those should dissipate soon after sunset. This would be a good period for travel, outdoor activities, or pre-storm preparations for the coming week. * First in a series of storms rolls in Sunday night through Monday. This one looks to be a solid wind maker in response to deepening low pressure inland over the Pac NW. Strong surface gradient with approaching cold front coupled with fast flow aloft (150 kt jet stream) should yield widespread gusts over 55 mph in the valleys with downslope wind prone areas over 70 mph. Sierra ridges could see 120+ mph. This has the potential to be one of the stronger wind events we`ve seen this season, so extra attention should be paid to weakened trees and unsecured outdoor objects. High wind watches have been posted. * The other issue, more prickly from a forecast standpoint, is snowfall potential in the mountains. Precip with this storm is modest due in part to a fairly weak AR signature. Guidance consensus has snow levels around 5500-6500 feet with variations +/- 500 feet. This of course places many of our mountain communities around Truckee-Tahoe-Lassen in that "uncertainty zone" where snowfall could go big (8-12") or go home (0-2") depending on how snow levels pan out. At pass elevations and in Mono County we`re more confident in seeing appreciable snows due to higher elevations. In the end we posted a winter storm watch to cover both snow potentials and strong winds for the Sun eve through Monday period. -Chris .LONG TERM...Tuesday through Saturday... Overall forecast remains on track with active weather pattern from Tuesday through Friday, then a possible break by next weekend. For Tuesday, the first storm system will begin with increasing moisture with the arrival of a moderate intensity atmospheric river. Warm air advection will bring a rapid rise in snow levels across the Sierra and far western NV during the morning. Farther north (roughly from Susanville-Lovelock northward), there may be a short period of light snow or a rain-snow mix Tuesday morning, while for the Surprise Valley and far northern Lassen County, a couple inches of snow could accumulate before the changeover to rain later in the day. The main concerns and impacts with this storm will occur later Tuesday afternoon through Tuesday night, when the peak rainfall intensity is accompanied with snow levels rising to near 8500-9000 feet. While the guidance remains consistent with the heavy rain potential for the Sierra and northeast CA, it still shows some uncertainty for where the heaviest rain occurs. Previous guidance had favored northeast CA, but in the latest guidance/ensemble data, the highest rain totals (2-4" with locally higher amounts) could range anywhere from Plumas County to northern Mono County. Farther east. rainfall amounts could exceed 1 inch in the western NV foothills and in eastern CA west of US-395, with 0.25 to 1 inch across the Reno-Carson Minden vicinity and less than 0.25 inch across West Central NV. In higher peaks (mainly above 9000-9500 feet) where precip remains as snow, a few feet of snow could accumulate by Wednesday morning. The combination of the warmer air mass and the higher elevation rain falling on existing snow pack will lead to rises on area rivers, with potential for localized flooding along smaller creeks/streams and in poor drainage areas. The heavier precip is likely to diminish on Wednesday, with leftover lighter showers possible Wednesday night into early Thursday. There could still be a moderate amount of additional rainfall during the day Wednesday near a portion of the Sierra during this wind-down phase. The next storm then arrives on Thursday, possibly starting by late morning for northeast CA, then spreading southward along the Sierra from Thursday afternoon through early Friday. This system will begin with high snow levels above 8500 feet, then drop to near 5000-5500 feet for northeast CA, near lake level for Tahoe and 6500-7000 feet for Alpine/Mono Counties by early Friday. Small stream flooding concerns and rises on area rivers will continue with this storm, especially if the midweek storm meets or exceeds the advertised rainfall amounts. The forcing along the cold front Thursday night could produce precip rates even greater than the midweek storm, although for a shorter duration. For western NV, winds will increase Thursday afternoon and evening, followed by a short period of rain overnight associated with the trough/cold front passage. Some partial spillover moisture could enhance rainfall totals a bit in foothills and western portions of Reno-Carson ahead of the front. For Friday, a weaker shortwave brushing across northeast CA could bring light showers near the Sierra and in western NV north of I-80. Then by next weekend, we should have a break in the action as a ridge builds into CA/NV. While our current forecast favors an inland ridge with temps near average, some scenarios set up the axis near or off the west coast. If this occurs we could see max temps 5-10 degrees colder with possible very light snow showers. MJD && .AVIATION... Light -shra/-shsn could bring MVFR cigs/vsby until around 03z for KTVL/KTRK Otherwise VFR conditions will prevail thru Sunday. Some mountain top obscurations will continue this evening near KRNO-KCXP. With gusty ridge winds continuing through early Sunday, turbulence will continue to be an issue across the Sierra and western NV. Significant weather-related impacts to aviation will begin early Monday as strong winds begin in higher elevations then spread to lower elevations during the day--leading to periods of LLWS, mountain wave turbulence, and rotor activity. MJD && .REV Watches/Warnings/Advisories... NV...High Wind Watch from late Sunday night through Monday evening NVZ003-005. Winter Storm Watch from Sunday evening through Monday evening NVZ002. High Wind Watch from Monday morning through Monday evening NVZ001-004. CA...High Wind Watch from late Sunday night through Monday evening CAZ070-071. Winter Storm Watch from Sunday evening through Monday evening CAZ072-073. && $$ For more information from the National Weather Service visit...
Area Forecast Discussion
National Weather Service Blacksburg VA
912 PM EST Sat Feb 4 2017 .SYNOPSIS... High pressure shifts east and offshore overnight. A weak cold front approaches Sunday before stalling across the Ohio Valley Sunday night into early Monday. Strong low pressure passing well to the northwest Tuesday will propel a cold front through the region during midweek. && .NEAR TERM /THROUGH SUNDAY/... As of 900 PM EST Saturday... Evening soundings along with surface observations show very dry air remaining in place tonight per PWATS of a tenth of an inch or less and dewpoints still in the single digits. This under clear skies has again allowed temps to fall off quickly this evening despite some lingering light southerly mixing. Given upstream mid deck associated with return moisture still west of the mountains, have lowered lows a few degrees across the east as well as the deeper valleys. This still will put most in the low/mid 20s before rising under increasing clouds after midnight. Did bump up lows on the ridges a category or so where expect weak warm advection, per increasing westerly winds at elevation, to steady readings out shortly before rising as the cloud canopy arrives. Precip chances still looking quite small late over the far west given the westerly trajectory and current split look to upstream echoes this evening. However the latest HRRR continues to show a quick surge in moisture advection just west of the region before daybreak, while attempting to drive some light precip into the I-77 corridor. Thus left in very low snow pops over the western mountains for now. Previous update as of 636 PM EST Saturday... Expansive Canadian surface anticyclone over much of the mid- Atlantic and southeast CONUS is beginning to gradually build east. Clear skies and lingering very dry air mass still remain in place and will continue to do so through midnight. That should allow for temperatures to really plummet fast over the next 4-6 hrs, particularly in areas that can stay decoupled/calm. We`ll then watch low/mid cloud shield, now extending across the Ohio and Mississippi River Valleys, advance across the central Appalachians after midnight and into the Virginia and North Carolina Piedmont into Sunday morning. No changes to PoPs at this time. However, with only little moisture recovery tonight it may be difficult to generate much of any wintry precip. Seems that only the SREF /NAM-based solutions generate any precip, with latest 18z GFS keeping our forecast area entirely dry. For this update, I`ve mainly blended in colder hourly temperature guidance into the grids to account for a likely sharp fall in temps through midnight, and then rising after midnight. Previous near-term discussion issued at 315 PM Saturday follows... Canadian high pressure over our region this afternoon will drift east this evening reaching the coast and push into the Atlantic ocean tonight. A northern stream shortwave will move across the Great lakes Sunday and then into the Northeast By early Monday. This system has a trailing warm front and cold front associated with it. A weak frontal system will move across our area late tonight into Sunday morning with a slight chance of precipitation. Very light precipitation will begin to develop across the western mountains just before daybreak from weak upper forcing and warm advection. With surface temperatures below freezing, a brief period of snow/sleet/freezing rain will be possible, but with QPF near zero, this is not expected to pose any winter weather problems across the forecast area. Precipitation will not reach areas east of the Blue Ridge. For PTYPE utilized the Topdown Procedure with the NAM temperature profiles for tonight into Sunday. Used a non-diurnal temperature curve for tonight with warm advection and clouds. Low temperatures tonight will range from around 20 degrees in the mountains to the mid 20s in the Piedmont. Light wintry mix Sunday morning will transition to some upslope sprinkles/drizzle by Sunday afternoon. Expect winds to become quite blustery behind the front Sunday afternoon into Sunday night. High temperature on Sunday will vary from the mid 30s in the mountains to the mid 50s in the Piedmont. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... As of 315 PM EST Saturday... You can expect a transition to milder temperatures this period as 5h heights build and 8h temps rise in advance of next upstream trough moving into the central U.S. Monday. Decided to keep isolated snow showers in western Greenbrier County Sunday evening, but overall shallow moisture is expected so nothing of consequence. A little brisk early in the evening before high pressure builds overhead late. Lows Sunday night will be in the upper 20s to lower 30s. Monday will be mostly sunny as winds shift to the south. Temperatures will rise to the 50s for highs. Monday night will see increasing moisture as a warm front traverses the Appalachians. Appears models agree on higher threat of rain over the mountains mainly from the Mountain Empire north to the Alleghanys, with limited threat of measurable over the NC piedmont. With southwest flow increasing aloft and clouds, temperatures stay on the mild side for lows, with most in the 40s. Tuesday best lift shifts north with the warm front with our area becoming more entrenched in a showery regime. Sfc low moves from the midwest Tuesday morning to the lower Great Lakes by dusk, with cold front advancing east to a Louisville to Memphis line. Models are adamant on keeping skies overcast but think some area east of the mountains could see a few breaks. Temperatures should pretty warm for early Feb with breezing southwest winds of 10 to 20 mph, with highs ranging from the lower 60s west to upper 60s/near 70 southeast. Some record highs may be approached, especially Bluefield which has a record high for Feb 7th of 63 set in 2005. Forecast showing 62. Best lift stays west but showers will nudge east to the mountains by afternoon. Tuesday night the low level jet shifts east across the area with strong lift with front. The 12z ECMWF showing rainfall amounts of over an inch in the NC mountains. At the moment given speed of system appears some of this is true as sfc low moves northeast allowing the front to slow some with unidirectional flow aloft. At the moment leaving thunder out of the forecast as timing overnight this time of year favors less threat, but will have to watch winds with line of showers given models forecasting an 8h jet of 45-60kts. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 200 PM EST Saturday... Some change this period mainly early as models have sped up colder air and drying behind the cold front. As such have slight chance to low chance pops mainly in the morning. Airmass dries a bit quicker. Another issue we have been highlighting in the Hazardous Weather Outlook is the winds along/behind the front. Models per forecast soundings have toned down the strength of the winds post frontal and with sfc low track further north and its direction of movement, climatologically we do not see a lengthy period of advisory level winds. However, with still 40-50kt jet Wednesday afternoon and 4-6mb pressure rises in 6 hours we will may mix some gusts close to advisory levels over the higher ridges, so will keep in the HWO, but back off on area covered by this to more of the mountains. Temperatures drop in the west late in the afternoon to the lower to mid 30s after starting the day in the 40s. Appears mainly dry and seasonal Wednesday night into Thursday though both the GFS/ECWMF showing an upper level system moving across in the Thu-Thu night time frame but overall moisture seems scarce and any precip will be light with very low pops advertised over the mountains. High pressure overhead Friday with warming trend next weekend. Model timing different with ECMWF bring next rain threat late Saturday through Sunday, while GFS keeps it dry. && .AVIATION /01Z SUNDAY THROUGH THURSDAY/... As of 635 PM EST Saturday... VFR SKC conditions through 06z, then trending VFR low/mid clouds (bases 060-090) after midnight from west to east. Potential for an MVFR ceiling at LWB and BLF overnight into the first part of Sunday but with upstream ceiling trends mainly VFR, confidence wasn`t high enough to include. Spotty, light wintry mix possible at these same two TAF sites but chances were too low to include in the TAF as well, with dry conditions prevailing otherwise. Light southeast winds (though up to 8 kts at ROA initially) begin a steady veer to southwest with speeds increasing to 8-12 kts after midnight. Winds turn gusty as a front moves across the area through the first part of the day on Sunday, with gusts as high as 25 kts at BLF and LWB. Medium confidence in ceilings, visibilities and winds throughout the TAF valid period. Extended Aviation Discussion... VFR/at times MVFR conditions for LWB and BLF, with VFR elsewhere Sunday afternoon into early Sunday night. Gusty west winds should begin to subside Sunday night, along with clearing of lingering cloud cover. Weak high pressure follows this system briefly for early next week with mainly VFR conditions expected Monday. Conditions will deteriorate Monday night as warm advection rain showers advance northeast into the region resulting in lower cigs and spotty sub-VFR vsbys espcly mountains. A strong area of low pressure will develop across the Midwest early next week promising to bring a longer period of sub-VFR conditions to the area starting Monday night and especially Tuesday into Wednesday with widespread rain and fog along with low clouds. Generally MVFR, but with periods of IFR expected. A strong cold front approaches from the west Tuesday night and crosses the area on Wednesday. After the front passes, expect improving conditions east of the Blue Ridge by Wednesday afternoon as showers along the front shift east. However lingering sub-VFR likely across the mountains for much of the day behind the front, with upslope low clouds and spotty rain/snow showers persisting under very strong post frontal northwest winds. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH NEAR TERM...AL/JH/KK SHORT TERM...WP LONG TERM...WP AVIATION...AL/KK