Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/04/20

Area Forecast Discussion
National Weather Service Caribou ME
716 PM EST Fri Jan 3 2020 .SYNOPSIS... Weak high pressure will build across the area tonight into Saturday. Low pressure from the Mid-Atlantic states Saturday morning will track south of Nova Scotia by Sunday afternoon. Weak high pressure builds Sunday night into Monday followed by weak trough of low pressure over the area Tuesday. Stronger low pressure from the Ohio Valley is expected to arrive Wednesday. && .NEAR TERM /THROUGH SATURDAY/... 705 PM Update: Temps were adjusted to fit the latest conditions. Clouds holding on across the CWA w/the lower clouds mainly across the northern 1/2 of the region. Dewpoints across the northern areas were slowly coming up. Some the higher resolution guidance such as the NAM12 and HRRR hint at the potential for some partial clearing later in the evening before clouds fill back in w/the apch of the cold front. This could lead to some fog formation. The NBM hinted at the fog potential as did the HREF w/the highest probabilities across the Downeast. Followed the daycrew w/the fog, but did add some patchy fog across some northern areas given the partial clearing potential and light winds. As far as the precip chances go, mainly slight chance(20%) and this will be across the n and w. Previous Discussion... A weak cold front will cross the area this evening and overnight. Moisture remains in place below 750mb, and if the front has enough lift, a few isolated showers are possible before midnight across the north. Winds will remain on the calm side, but it may become a little breezy in the north when the front does pass. With dewpoints remaining elevated Downeast and cloud bases relatively high, there is the chance for some patchy fog tonight into Saturday morning. This is especially evident along river valleys via the HREF vis probabilities. Fog will linger until the front passes offshore, with weak cold air advection. Saturday will again see above normal temperatures for the season, but a handful of degrees cooler than Friday. 500 mb jet moves very little, but by the time the next weather system tracks towards New England, a trough will be pushing out of the Great Lakes. This will slow onset time of precip until Saturday evening and overnight, although some scattered rain or snow showers cannot be ruled out in the Bangor Region Saturday afternoon. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... Next light pcpn-maker wl be in the offing for the beginning of the short term pd. Sfc low located ovr the Upr Midwest wl begin to drift to the south and east tonight bfr weakening. Sfc low ovr the TN Vly wl strengthen as it heads twd the northeast tomorrow as H5 trof deepens back to our east. By the start of the pd all guidance is suggesting sfc low wl be located in vicinity of Cape Cod. Guidance has slowly come into agreement on ultimate track of sfc low to the south of our waters. Hv contd with mention of likely pops ovr Downeast zone for Sat night. Question then bcms what happens further north. As mentioned by previous shift, H8 low looks to be the catalyst for snow acrs the north. 12z guidance rmns with this idea and hv retained chc pops acrs the entire CWA aft 06z. Winds look to pick up behind low pressure on Sun aftn and may result in blowing snow acrs the north, especially over lakes and fields. Winds look to gust to btwn 20-25kts. Cold air streaming in on nrly flow on Sun wl drop high temps closer to normal late in the weekend and blo normal to start off the week. Brief ridge of high pressure wl affect the region Sun night into the early part of Monday before next wmfnt brings overrunning pcpn to the wrn part of the region starting late Mon aftn but weakening as it heads east into CWA. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Vry light snow wl accompany a weak trof lifting north thru the area Mon night. As wmfnt lifts north on Tue expected that temps wl climb to abv normal values once again with highs in the m20s acrs the north and abv frzg for Downeast zones. The next in the way of significant storms appears to approach the NE on Tue with potential Nor`easter on Wednesday. 12z GFS, EC, GEM, UKMET and majority of GFS ensemble members showing fairly potent storm by this time. Way too early to get specific on details this far out but above average confidence exists for a storm. This is still highly dependent on upr air features coming together at just the right time thus phasing comes into question as to location of low and ultimately ptype as a result. Either way, something to certainly keep an eye on over the weekend. High pressure wl build over the area as system departs on Thu with dry and cooler wx thru the end of next week. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: MVFR ceiling conditions will persist through the afternoon at FVE, CAR, and PQI. A period of IFR is possible for FVE and CAR tonight as a cold front passes over. Downeast, VFR is expected through early tonight. Patchy fog will be possible after midnight along river valleys near BGR and the coast into BHB through mid-morning. SHORT TERM: Sat night...MVFR at all terminals as weak system approaches. Downeast terminals may see IFR restrictions during the bulk of the nighttime hours in -sn. Light N wind. Sun...Slow improvement to VFR during the morning hours though may see lingering MVFR stratus for northern terminals. NW wind 10-15kts gusting to 25kts. Sun night/Mon...Mainly VFR. Light N winds Sun night becoming light S Mon. Mon night/Tue...MVFR in very light -sn Mon night. MVFR cigs may linger across the north on Tue with improvement to VFR for Downeast. Light S winds. Wed...IFR in sn during the day. Potential for NNE winds. && .MARINE... NEAR TERM: Conditions will continue to remain below SCA criteria with waves 2-3 feet. SHORT TERM: SCA will likely be needed late Sat night through the day on Sunday. Winds may come close to gales Sun aftn for the outer waters. Winds drop blo SCA levels early Mon morning. Seas increase abv 5 ft in srly swell Sun morning and remain above SCA levels through midnight Sun night. Seas wl then be aob 5 feet into the middle of the week. Winds will be under SCA levels until early Wed morning. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...Cornwell/Hewitt Short Term...Farrar Long Term...Farrar Aviation...Cornwell/Hewitt/Farrar Marine...Cornwell/Hewitt/Farrar
Area Forecast Discussion
National Weather Service Des Moines IA
807 PM CST Fri Jan 3 2020 .UPDATE... Issued at 753 PM CST Fri Jan 3 2020 Strong PV anomaly continues to pin wheel over central Iowa this evening. The heaviest snowfall totals should behind us now as the anchored band of heavy in north central Iowa has started to push south. HRRR/RAP in solid agreement with a more westerly trend for snowfall through the remainder of the night, likely due to drier air that has now wrapped around the southeasterly edge of this system. The RAP model highlights the potential for heavier snowfall rates on the western periphery of the upper low with appreciable lift and super saturation with respect to ice through the dendritic growth zone. This would highlight areas generally between Hwy 71 and I-35 over the next couple hours. The more accelerated movement of the snowfall should limit total amounts, but some could see a quick 1 to 2 inches, possibly up to 3 in localized areas. Visibility may become quite low at times in areas where heavier snowfall rates combine with gusty northwest winds. Conditions are expected to improve overnight as the system quickly exits the area. && .DISCUSSION.../Tonight through Friday/ Issued at 318 PM CST Fri Jan 3 2020 .Overview...Quick shot of precipitation (mainly snow) this afternoon into tonight will create tricky Friday evening travel across parts of central Iowa. Winds will be stronger over western Iowa where total snowfall should be less, but winds in general with falling snow will have reduction on visibility through snowfall end tonight. A cold front will pass through on Sunday with gusty winds with a clipper bringing precipitation chances on Tuesday. Temperatures will be near if not mostly above normal for the next week. .Details...Emphasis on this forecast cycle was on the quick shot of snow that is already moving through this afternoon and will continue to do so through tonight. Already have precipitation, mostly snow, but some rain on the southern periphery, over many parts of central Iowa mainly north of I-80. This precipitation is associated with warm air advection ahead of the surface low that is over southwest Minnesota early this afternoon and will be diving southeastward tonight as the PV anomaly over central South Dakota moves in a similar direction. Initial snow over northwest Iowa this morning did accumulate for a bit, but at midday the roads were mainly wet as road temperatures were near if not above freezing. However, recent phone calls from spotters reported snow beginning to accumulate once again over parts of north central Iowa. Challenge today has been where the band of heavier snow may set up, the pivot point where snow totals may be highest, and where the highest winds will be and if they will coincide with the higher snowfall. There has been general agreement that the band may be a little more northwest to southeast oriented than previously forecast. The 12z HREF and latest WPC and NBM are highlighting a corridor from our northwest forecast area through our east central (roughly Estherville to Marshalltown line) as the axis of highest snowfall. Snowfall rates may exceed 1"/hr at times in this corridor as shown by the 12z HREF and recent HRRR and cause significant reduced visibility. As for the pivot point, the 12z HREF 4" probability has relatively higher probabilities over Tama and Marshall counties and latest NBM and some other CAMs also indicate a longer duration of snow as the system pivots through this evening over this area. While current forecast is around 2.5 to 3 inches in this area, it may need further refinements going forward this evening. Overall, the snowfall forecast has narrowed the swath of highest snowfall. As for winds, the core of the strongest winds should remain west the surface low over western Iowa as the low moves southeastward over central Iowa. This will create visibility reduction to a degree, but it is not clear if it will be to the same reduction where snow rates may be higher. Further, it is also expected near and west of the low track that snow duration will be shorter than in the pivot point/east of the low track. So, for now, have continued to focus Winter Weather Advisory along the low track and through the pivot location where snow totals and impacts may be greatest. Trends upstream will need to be watched this evening for any possible expansion. This quick system will exit the area overnight with snow ending from northwest before midnight to southeast before daybreak Saturday. A transient mid-level ridge will pass over the state on Saturday with increasing amounts of sunshine and dry conditions. Another cold front trailing from a surface low pressure moving over southern Canada will cross the state Saturday night into Sunday morning. Soundings show an increase in moisture in the mid-levels, but not enough for precipitation. However, in the cold air advection regime expect gusty winds to develop behind the front early Sunday morning through midday Sunday before decreasing later in the afternoon. Winds at this point remain on the cusp of a wind advisory so will need to keep a watch on this time period. Into next week, there are two possible systems with mid-level ridging fostering dry conditions between them. The first will be later Monday into Tuesday and will bring light snow (perhaps initially rain) as a clipper passes quickly through the region. The latter system later Thursday into Friday may bring a shot of precipitation with the highest chances over the southeast part of the state. However, like today`s system a week ago, it will depend on phasing of a northern and southern stream wave, which remains uncertain at this time. && .AVIATION.../For the 00Z TAFS through 00Z Saturday evening/ Issued at 535 PM CST Fri Jan 3 2020 Snow and low stratus will be the main forecast concerns for the current TAF period. Cigs have been up and down over central Iowa for the last few hours, ranging anywhere from MVFR to LIFR at times. Expecting IFR to prevail at most TAF sites into the overnight hours along with visby restrictions from passing -SN/SN. Expect gradual improvement from west to east across the area Saturday morning and afternoon as cigs rise and cloud cover diminishes. && .DMX WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 1 AM CST Saturday for IAZ039- 047>050-061-062. Winter Weather Advisory until 9 PM CST this evening for IAZ004- 005-015>017-023>028-035>038. && $$ UPDATE...Martin DISCUSSION...Ansorge AVIATION...Martin
Area Forecast Discussion
National Weather Service Goodland KS
414 PM MST Fri Jan 3 2020 .SHORT TERM...(This evening through Saturday night) Issued at 119 PM MST Fri Jan 3 2020 Water vapor imagery and 500 mb RAP analysis showed northwest flow over the region today as a trough pushed east across the Plains. To the west, upper ridging built along the west coast. Some mid level clouds traveled over the area, with northwest winds observed at generally 10 to 20 mph. At 1 PM MST, temperatures were mainly in the low 40s. Dry weather is expected to continue tonight as high pressure moves into the region ahead of the upper ridge. Mid level clouds could increase in the evening, particularly east of the Colorado border, before clearing after midnight. Temperatures fall into the low 20s, with light winds shifting from northwest to west. Mostly sunny skies are forecast on Saturday as high pressure moves southeast and a weakening ridge progresses to the Plains. Warmer air filters into the region and temperatures climb into the mid 50s to low 60s, with southwest winds at 15 to 20 mph. A shortwave traverses the northern Plains Saturday night, sending a cold front through the area. No precipitation is currently anticipated, but breezy northwest winds appear likely behind the front. Due to mixing, temperatures stay a little warmer in some places, ranging from the low to upper 20s. .LONG TERM...(Sunday through Friday) Issued at 149 PM MST Fri Jan 3 2020 The forecast will remain dry with near normal temperatures through the extended forecast. Normal temperatures for this time of the year are in the low 40s for highs and the mid-teens for lows. A deamplifying ridge will move over the Tri-state region through the day Sunday. A deepening upper trough coming ashore over the West Coast will progress eastward over the Rockies. High temperatures will be right around normal, ranging from the low to mid-40s. Lows will be in the low to mid-20s. Monday will be breezy as the trough advances into the Central High Plains and a surface lee cyclone develops. Though mid-levels do try and moisten up through the afternoon as the low moves through, am currently looking at dry conditions remaining prevalent through the day. Highs will top out in the 40 with lows ranging from the mid-teens to mid-20s. Northwest flow aloft will set up over the Central High Plains on Tuesday with a ridge over the West Coast. The ridge will move eastward, over the Tri-State area by Wednesday. Wednesday is expected to be the warmest day of the extended forecast with highs ranging from the mid-40s to mid-50s. A broad, upper level trough will move into the region on Thursday with a low moving through the Dakotas and a cold front pushing into the Tri-State region from the northwest. Precipitation is not expected, however, temperatures will be impacted, returning to near normal with highs in the low to mid-40s and lows in the mid- teens to low 20s. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 412 PM MST Fri Jan 3 2020 VFR expected at both KGLD and KMCK through the TAF period. Occasional high clouds will spill across the Rockies with a ridge located over the western CONUS. At the surface, winds will be light and variable tonight, but some increase from the southwest by Saturday afternoon as a trough of low pressure develops across eastern Colorado. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...JBH LONG TERM...AW AVIATION...024
Area Forecast Discussion
National Weather Service Wilmington NC
929 PM EST Fri Jan 3 2020 .SYNOPSIS... A pair of cold fronts will bring showers to the area through early Saturday. High pressure will rebuild from the Gulf Coast states Saturday night through Monday. This will allow cooler and drier area to impact the region. The next cold front approaches Tuesday before pushing offshore into Wednesday. && .UPDATE... Tweaks to temperatures and timing of showers was the main focus of this late evening update. 01z HRRR run looks very reasonable with its eastward movement of precip overnight into Saturday morning. Elevated instability is diminishing across the Pee Dee region into Lumberton and I have removed thunder from the forecast there. Dense sea fog continues offshore, and south- southwest wind is keeping visibility very low in Southport and Oak Island according to webcams. && .NEAR TERM /THROUGH SATURDAY NIGHT/... Main concern over the next 36 hours includes chances for moderate to heavy rainfall at times during heavier showers and isolated thunderstorms. Surface low pressure system developing out of the Gulf of Mexico will bring developing fronts passing through the Carolinas. A warm front pushes through the region today with high temperatures in the mid to upper 70s, which is on average about 20 degrees above normal for early January. A cold front approaches from the west and will bring chances for rain showers and isolated chances for thunder mainly to locations along and west of I-95 this evening. Latest model guidance indicates the line will become more disorganized and scattered as it approaches the coast late this evening into the overnight hours. Chances for rain will continue Saturday with scattered precipitation until a second cold frontal passage occurs late Saturday into early Sunday morning with rain moving off the coast. Temperatures Saturday will drop into the mid to upper 60s, which is still on the order of about 10 degrees above normal, but the second frontal passage will bring low temperatures Saturday night into the upper 30s to lower 40s, which is closer to normal for early January. && .SHORT TERM /SUNDAY THROUGH MONDAY/... A different air mass will be over the area on Sunday as deep layered NW flow ushers in dry conditions (pwat around 50% of normal), cooler high temps in the low to mid 50s, and abundant sunshine. Subsidence inversion above ~2500ft will limit mixing but with center of ~1030mb surface high still well to our SW near central Gulf Coast, expect NW winds 8-13 with gusts to 15-20mph to persist, making temps feel a little cooler than they really are. The surface high will gradually settle over the SE US as it weakens through Monday allowing winds to gradually diminish. Meanwhile, mid and upper flow will become more zonal. This leads to a chilly start on Monday morning (mid to upper 30s), with another dry and sunny day warming to slightly above normal values into the upper 50s to near 60 most zones. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... The next deep layered trough and associated sfc cold front approach on Tuesday. Expect prefrontal airmass to lead to warmer temps (low-mid 60s) and an increase in clouds. Most of the daylight hours currently look dry although have maintained low chance pops far western counties which is in line with latest guidance trends. Better precip chances exist Tue night as forcing improves aloft with PVA ahead of H5 trough and sfc boundary swings through. Moisture overall is lacking though so have kept PoPs in the low chance variety for now. Wednesday and Thursday look dry and cooler as airmass changes again with deep layered ridging taking over. Wednesday/Wednesday night has the potential to be the coolest period of the forecast although am only advertising slightly below normal at this time. Showing a slow, modest increase in PoPs at the end of next week as next frontal system begins to impact the area, but low confidence in related specifics at this time. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... IFR sea stratus affecting coastal terminals attm due to warm, moist southerly flow over cool water. Area webcams showing scattered IFR fog too but that isn`t affecting the terminals attm. It could impact approaches, especially in SC. Expect this fog and stratus to persist for several hours, perhaps until winds become more westerly later tonight. Bands of showers moving in from the west should begin to affect inland terminals in the 01Z to 03Z time frame and reach coastal terminals in the 06Z to 09Z window. Generally expect MVFR cigs with the bands of showers though tempo IFR is not out of the question. It should take until about 18-20Z for cigs to improve to VFR and for shra to end. Expect S to SW winds of 10 to 15 KT with higher gusts to become SW late tonight and W to SW after sunrise. LLWS potential exists at times all terminals tonight, mainly in the 02Z to 08Z time frame. Extended Outlook...VFR conditions return for Saturday night through Monday. Cold frontal passage expected late Tuesday could produce MVFR conditions showers. && .MARINE... Small craft advisory (SCA) begins this afternoon and evening as cold front approaches from the west. As warm air moves over the waters for the next ~12 hours, dense marine fog is a possibility especially near shore. Another cold front will push through the offshore waters late Saturday and could bring even worse conditions as gales are possible. Waves 4 to 7 feet this afternoon through Saturday with winds shifting from the south to the southwest at 15 to 20 kts and gusts in excess of 25 kts into Saturday afternoon. Conditions worsen Saturday evening with waves between 6 and 10 feet and a hard wind shift from the southwest to the northwest at between 25 and 35 kts with gusts up to 45 kts at times. Expect the potential NW gales from Saturday night to ease to SCA levels through Sunday morning, and then come down below SCA threshold through Sunday afternoon as the recent cold front pushes further offshore and high pressure slides east along the Gulf Coast. Much tamer marine conditions develop during Monday as high pressure settles over the area allowing winds/seas to fall to at or below 10kt/3ft. Return flow develops Tuesday ahead of next front, with potential for low end SCA conditions later Tuesday and Tuesday night. Gusty W/NW winds and associated short period seas may keep marine conditions hazardous into Wednesday behind the front. && .CLIMATE... As recently highlighted on our social media outlets (@NWSWilmingtonNC), Florence, SC and Lumberton, NC have broken high temperature records, both hitting 79 degrees. Meanwhile, Wilmington has tied its record high of 77 degrees. Expect more info in our RERFLO, RERLBT, and RERILM text products around 5pm. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...Dense Fog Advisory until 7 AM EST Saturday for NCZ110. MARINE...Dense Fog Advisory until 7 AM EST Saturday for AMZ250-252-254- 256. Gale Watch from Saturday evening through Sunday morning for AMZ250-252-254-256. Small Craft Advisory until 9 PM EST Saturday for AMZ250-252- 254-256. && $$ SYNOPSIS...MCW UPDATE...TRA NEAR TERM...MCK SHORT TERM...MCW LONG TERM...MCW AVIATION...RAN CLIMATE...MCW
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
540 PM CST Fri Jan 3 2020 .SYNOPSIS... Issued at 311 PM CST Fri Jan 3 2020 H5 analysis from earlier this morning had a large ridge of high pressure extending from southern California north into British Columbia and Alberta. East of this feature, a strong shortwave and trough of low pressure extended from the western Dakotas into northeastern Nebraska. Another shortwave trough of low pressure was located from central into southern Texas. East of these two features, broad southwesterly flow extended from the Gulf of Mexico into the Mid Atlantic. Across the central CONUS this morning, the Dakota shortwave had led to snow showers across eastern South Dakota, and forced a cold front through the forecast area earlier this morning. Winds were gusty behind the exiting cold front, particularly over northern and northeastern portions of the forecast area. As of 2 PM CST, winds were gusting as high as 31 MPH at O`Neill and temperatures were in the 30s to around 40. && .SHORT TERM...(This evening through Saturday night) Issued at 311 PM CST Fri Jan 3 2020 The main forecast challenges in the near term are temperatures and wind potential. For tonight: Surface high pressure, will build south from north central Nebraska into central Kansas tonight. On the western periphery of the high, abundant mid level cloudiness will persist into the evening hours across western portions of the forecast area. Clouds will then begin to dissipate overnight as the high builds south into Kansas. As for the threat for light precipitation tonight on the western periphery of the high, the latest NAM12 soln does generate some very light precipitation from the Pine Ridge into the western Sandhills early this evening. With each run of the HRRR this morning, dry conditions continue to be advertised. With no model support for pcpn other than the NAM12, will hold onto a dry fcst for tonight. A warm front will push east of the area Saturday morning with a pre frontal trough extending across the forecast area Saturday afternoon. Winds will be relatively light during the afternoon along the trough. The latest MAV guidance has mid to upper 50s for highs Saturday for Valentine and North Platte. With limited mixing along the surface trough Saturday afternoon and snow cover, will opt for the cooler MET guidance which favors highs from the mid 40s to around 50 over snow covered areas. Across far southwestern portions of the forecast area, highs will top out in the middle 50s. A clipper system will track along the ND/Canadian border Saturday night, forcing a cold front through the forecast area. Gusty winds will develop behind the front Saturday night with the strongest winds expected over north central into northeastern areas. The models do drop an area of strong H85 winds from South Dakota into Nebraska Saturday night. The degree as to how much of this wind can mix to the surface is still uncertain. The latest Bufkit sounding data, including the GFS and NAM12 solns, do not mix winds much off of the surface Saturday night. Even mixing up to H900 Saturday night only yields gust potential to 40 to 45 MPH. With the FROPA being at night, mixing potential will be limited somewhat. That being said, do not see any issues with headline type winds Saturday night. The blowing snow threat should be very limited as well as recent warm days have crusted over the existing snow cover across the forecast area. .LONG TERM...(Sunday through Friday) Issued at 311 PM CST Fri Jan 3 2020 Surface high pressure will build into the area Sunday with mainly clear skies and light winds. Highs Sunday will be in the lower 40s. A weak clipper system will track across North Dakota Sunday night into Monday. There will be an increased threat for rain or snow showers Monday. Given the fast movement of the system and a lack of moisture, any precipitation will be very light. After Monday, a dry pattern will continue as ridging builds into the central CONUS Tuesday into Wednesday. A southern stream trough will bring precipitation to the southern plains and Mississippi valley late Thursday into Friday. This will be followed by another ridge building into the central Conus Friday night into Saturday. Highs next week will generally be in the upper 30s to 40s. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 539 PM CST Fri Jan 3 2020 Scattered flurries underway across wrn Nebraska are expected to move south and out of the area this evening. VFR is expected thereafter throughout wrn and ncntl Nebraska. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Buttler SHORT TERM...Buttler LONG TERM...Buttler AVIATION...CDC
Area Forecast Discussion
National Weather Service Marquette MI
628 PM EST Fri Jan 3 2020 .SHORT TERM...(This evening through Saturday) Issued at 324 PM EST FRI JAN 3 2020 GOES visible shows mostly overcast skies across much of the Upper Great Lakes region as RAP analysis shows a passing wave across the Dakota/MN border. This wave is bringing -SN across MN/IA this afternoon, but the UP remains dry. Temperatures remain a touch above normal this afternoon and should remain at or slightly above normal through the short-term period. Heading into tonight, GFS and WRFs 850mb temps remain warmer than NAM/EC/GEM, -7C to-8C vs -10C to -12C, but have chosen to continue the light -SHSN/-FZDZ chances tonight. Model soundings show limited DGZ saturation with inversions at or below 3000 feet depending on model/location. A shortwave trough will also be passing across Upper Michigan tonight, which may give a little extra push for some flurry/fzdz development. There are a few model soundings that dry out further tonight cutting off these chances. Overall have generally capped chances at 20% or less as any precipitation will likely create minimal accumulations and impacts, similar to this morning`s light fzdz/flurries. By Saturday morning, the shortwave from overnight will be east of the UP as rising heights and slight ridging builds in from the west. Winds are expected to slowly back from the SW by the afternoon, but lingering nuisance precip chances will remain until these winds change over. .LONG TERM...(Saturday night through Friday) Issued at 414 PM EST FRI JAN 3 2020 Models suggest that a progressive pattern will prevail into next week with shortwave troughs bringing periods of light snow followed by batches of colder air with LES. Temps are expected to drop below average from Tue into Wed with recovery later in the week as WAA strengthens ahead of a developing mid level trough in the wrn CONUS and sfc troughing moving toward the Upper Mississippi Valley. Saturday night, lingering anticyclonic w to wnw flow along with 850 mb temps to around -10C may support some light lake effect pcpn into the Keweenaw and northeast portion of Upper Michigan. With relatively shallow moisture, inversion heights from 3k to 4k ft, some fzdz may mix in with any light snow or flurries. Sunday, a shortwave trough moving in from the Northern Plains with moderate 700-300 qvector conv will support widespread light snow across Upper Michigan. However, with limited moisture inflow, accumulations are expected to remain in the 1 to 2 inch range. Some additional lake enhancement may be possibly with southerly flow off of Lake Michigan, but with marginal instability, 850 mb temps to -7C, and a veering vertical wind profile any amounts should remain light. Gusty west winds will develop, especially over the Keweenaw, behind the surface trough with strong CAA and isallobaric gradient. Sunday night into Monday, w-wnw flow LES will increase as 850 mb temps drop to around -15C. Although amounts may be limited as the deeper (850-700 moisture) lifts off to the northeast, advisory level accumulations are still possible if any persistent areas and stronger bands develop especially to the east of Munising. Tue-Wed, another shrtwv trough with a batch of light snow is expected Tue with even colder air (850 mb temps to near -20C) in its wake that will bring nw flow LES. Thu-Fri, conditions will moderate with the potential for some light WAA snow. A cold front with somewhat colder air will then move through toward the end of the week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 626 PM EST FRI JAN 3 2020 Expecting MVFR cigs to prevail at the terminals through the forecast period with a chance of temporary higher-end IFR cigs at IWD. There is a chance for some -SHSN or -FZDZ tonight downwind of Lake Superior but will likely remain sporadic so have left it at VCSH for now. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 324 PM EST FRI JAN 3 2020 NW winds will back to the SW on Saturday night as a developing low pressure system approaches Lake Superior from the NW in Canada. Pressure falls ahead of this low pressure will help increase the winds in addition to the increased pressure gradient. Winds veer to the NW by Sunday afternoon increasing to gale force by Sunday evening through Sunday night, a gale watch has been issued. Expect these NW winds to slowly diminish through the day Monday into Tuesday and will remain below 25 knots through Thursday. Some models suggest a low pressure system to develop across the Northern Plains which may increase winds from the south up to 30 knots. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Gale Watch from Sunday evening through Monday morning for LSZ249>251-265>267. Gale Watch from Sunday afternoon through Monday morning for LSZ162-240>245-263-264. Lake Michigan... None. && $$ SHORT TERM...JAW LONG TERM...JLB AVIATION...Voss MARINE...JAW
National Weather Service Charleston WV
1009 PM EST Fri Jan 3 2020 .SYNOPSIS... Low pressure brings rain into Saturday. Cold front passes early Saturday. Colder air arrives with snow showers Saturday night. Another cold front crosses early next week. && .NEAR TERM /THROUGH SATURDAY/... As of 1000 PM Friday... The forecast holds strong and no changes were needed at this time. Rainfall amounts will continue to slowly taper off through the period. As of 620 PM Friday... The forecast remains on track and no changes were needed at this time. As of 1250 PM Friday... This is one of those periods where confidence is high that there will be light to moderate rain around for most of us, but a few hours of dry are possible here and there. Have generally low confidence on timing those out individually, so a more broad brushed approach was used for POPs, utilizing a blend biased towards the NAM and HRRR to try to capture some of these times of lower precip chances. So do have a period of chance POPs across the eastern forecast area this afternoon, gradually filling back in as the next slug of rain arrives from the southwest. A couple waves of low pressure at the surface followed by an upper trough/low will drive the overall pattern tonight and Saturday. The first will ride up through the middle Ohio River Valley overnight, gradually pushing a cold front through from west to east. Another wave develops along the front Saturday, slowing is progression down a bit as it tries to cross the Appalachian spine. Have the area of highest POPs transitioning across the forecast area overnight into Saturday with these waves and cold front. By Saturday afternoon, the upper level trough axis moves into the middle Ohio River Valley, turning the precipitation to more showery in nature by late afternoon. Colder air also arrives with this feature, and rain should begin transitioning to snow late Saturday. At the surface, expect nearly steady to slowly falling temperatures through the day as cold air begins filtering in. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 110 PM Friday... Colder air moving into the region behind departing cold front will result in a change over to light snow area wide Saturday night. Still looking at less than half an inch across the lowlands, with a general 1 to 4 inches across the higher terrain. In addition, gusty winds are expected Saturday night into early Sunday across the area, particularly the higher terrain. A few spots 3500-4000 feet elevation could hit advisory criteria gusts of 40 kts, but coverage not expected to be enough to warrant an advisory. Light snow showers are possible across the north late Sunday night into Monday from a passing disturbance to the north, but any impacts should be limited. Another disturbance will affect the region mid week with rain and snow showers once again with light accumulations possible. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 150 PM Friday... A trough moves across the area Wednesday bringing a precipitation chance. Snow may fall early in the day and then change to rain as the day progresses; however, in the mountains, snow will likely linger throughout the day and taper off overnight. High pressure is expected for Thursday and part of the day Friday. This is followed by another trough that may yield precipitation over the weekend. Temperatures are expected to remain cool on Wednesday and then warm up above normal again through the end of the work week as warm air is pulled into the area ahead of the next system. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... As of 640 PM Friday... Unsettled weather persists through this period along with low MVFR to around IFR CIGs and variable VIS as low as IFR. A southwest flow changing over to a more westerly flow by sunrise will advect cooler air in as a cold front sweeps through the area. This will cause post frontal stratus to occur at all sites bringing down CIGs to essentially widespread IFR. Visibility will improve early Saturday morning as the front kicks out and winds pick up out of the northwest pulling in drier, cooler air. This will help much of the area to eventually improve to VFR VIS by sunrise although CIGs will get little improvement until late afternoon. The eastern mountains will not gain much improvement to either categories and eventually worsen as an upper level trough brings in more precipitation late Saturday afternoon maintaining around low MVFR conditions into Sunday morning. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of category changes may vary into Saturday afternoon. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SAT 01/04/20 UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 EST 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09 CRW CONSISTENCY M H H H H H H H M M H H HTS CONSISTENCY L M M H H M M L H H H M BKW CONSISTENCY H H M H H L H H M M H M EKN CONSISTENCY H M H M M M M H H L M L PKB CONSISTENCY H H H M H M M M M H H M CKB CONSISTENCY M M M L L M M M M M M M AFTER 00Z SUNDAY... IFR conditions possible in rain and low clouds for the higher elevations trough Saturday night and also in snow showers from Saturday night through Sunday morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...MZ/JP NEAR TERM...MZ/JZ SHORT TERM...SL LONG TERM...JLB AVIATION...JZ
Area Forecast Discussion
National Weather Service Blacksburg VA
651 PM EST Fri Jan 3 2020 .SYNOPSIS... Passing waves of low pressure will bring spotty rain to the mid- Atlantic region this evening and tonight. A cold front will pass east across the central Appalachians on Saturday, resulting in gusty northwest winds and mountain snow showers for Saturday night. High pressure will return for Sunday, resulting in clearing skies and near-seasonable temperatures. && .NEAR TERM /THROUGH SATURDAY/... As of 651 PM EST Friday... High wind watch for Saturday evening into Sunday morning is in effect for along the southern Blue Ridge mountains. Modified the temperatures with the latest surface obs, and their trends for this evening into tonight. Periods of rain,drizzle and fog are expected to continue tonight into Saturday morning. Still looks like the heaviest rain will occur across the southeastern portions of the forecast area. The HRRR and HiRes Arw-East keep the stronger convection to our south with the better instability and some outflow boundaries to work with. More changes later tonight. As of 330 PM EST Friday... Doppler radar indicates widespread light to moderate passing across the central Appalachians through the mid-Atlantic this afternoon as waves of low pressure pass across the region in this unseasonably- moist southwesterly windflow. Synoptic analysis indicates a deep upper level trough situated across the Plains states, with a surface cold front stretching from the central Great Lakes through the western Gulf coast. This evening and overnight, expect rounds of rain to pass across the area. Heaviest/most widespread rainfall will occur across the Virginia Southside into north-central North Carolina, where deepest moisture is located - precipitable water values here edging around or above 1.5 inches. That stated, do not anticipate rainfall rates or amounts that will amount to any flooding, with totals by Sunday morning in the 1.00 to 1.25 inch range. Amounts further north and east will be significantly lower. The deep moisture and widespread cloudcover will also maintain patchy, locally dense fog, especially where the low clouds intersect the higher terrain. Expect little change from evening temperatures, with lows tonight ranging from the mid/upper 40s across the mountains to the low 50s for the Piedmont. The cold front will pass east across the central Appalachians on Saturday morning, causing winds to shift westerly with its passage. Wind speeds will gradually increase through the afternoon as high pressure builds in, though strongest winds will not arrive until the base of the upper level trough moves through Saturday night. Downsloping will make for clearing conditions in the east and a wider range of afternoon temperatures, with afternoon highs ranging from the upper 40s west to the low 60s east. The approaching upper trough will also bring colder air during the afternoon/evening which will cause rain to change over to snow showers by sunset across western Greenbrier County. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 200 PM EST Friday... The biggest concern post-cold front will be an increasing northwest wind. The latest guidance offers a solution of 6mb pressure rises maximized Saturday night with 850mb winds around 40 to 50 kts right at or slightly below the inversion height. The area along the crest of the Blue Ridge between roughly Boone, NC and Roanoke, VA looks to have the greatest impact with the winds. There is a concern for wind gusts approaching the 60mph threshold Saturday night with a gradual tapering Sunday morning. Will be issuing a High Wind Watch for this area. Much of the rest of the region west of the crest of the Blue Ridge, and perhaps even a couple tiers of counties east of the crest of the Blue Ridge could be strong candidates for Wind Advisories. However, we are still going to allow for one more look of the newest guidance tonight to see how well/poor this potential is trending. However, the current forecast time is appropriate for heightened awareness for the potential for the high winds, hence our High Wind Watch. These strong northwest winds ushering in colder temperatures will have the impact also of lifting residual low level moisture not only into clouds, but first rain showers, and then transition into snow showers as the night progresses. Our current forecast has most locations between roughly western Greenbrier County, WV south into the Northern Mountains of North Carolina with less than one inch of snow during the Saturday night/early Sunday time frame. However, higher elevations could see snowfall in the one to three inch range, with an even smaller subset of peaks in the four to six inch range. No advisories for snowfall are planned at this time given the timing of the event still more than 24 hours away, and the less than desired amounts and areal coverage to justify an advisory at this time. Blowing snow could become a winter headline factor across the Northern Mountains of North Carolina as this would be an area that can expect the very strong/damaging winds plus at least a small covering of snowfall. By Sunday afternoon, low level winds are forecast to have backed to the west-southwest. While still maintaining healthy speeds, their orientation will not be as conducive for mixing to the surface or helping to generate snow showers. While eastern parts of the region will have clear skies by daybreak Sunday, the remainder of the region should see skies clear by early Sunday afternoon. Sunday night, the low level flow veers northwest again, but the amount of drier air that will have arrived across the region will limit any upslope cloud/snow shower development. Perhaps western Greenbrier County, WV will see some isolated snow showers Sunday night. We will have to continue to monitor these trends, but indications are looking promising again for additional wind headlines Sunday night into early Monday, with the best probability this time across northern sections of the forecast area. Surface high pressure will be across the region by Monday afternoon, and start to transition to the coast by Monday night. This will be in response to an approaching upper level trough that will be heading toward the mid-Mississippi River Valley. Low level winds across the region will trend southwest. This will mean a trend towards warm air advection, and moisture levels will start to increase. Clouds will be on the increase across the area by midnight, some patchy light precipitation will be inching its way northward across the far western parts of the forecast area. There is some question to just what the low level thermal profile will be in regards to the p-type. At this time, will keep the forecast a simple rain versus snow forecast based solely upon the surface temperatures. Temperatures during this portion of the forecast will about five to ten degrees above normal. Forecast confidence during this segment of the forecast is moderate. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 1230 PM EST Friday... Tuesday into Wednesday, we are expecting precipitation across the area thanks to two systems. The first system will have its origins as a developing shortwave trough in the Central Plains states Monday night. By Tuesday, this feature will head across the mid-Mississippi River Valley. In advance of this feature, southwest flow will develop, and help advect Gulf of Mexico moisture into the region. However, this advection is not expected to be as robust as compared to similar systems so far this winter. An associated cold front will cross the area Tuesday evening, but this is also about the same time the second system make its contribution. The next system will be a northern stream shortwave trough that will head across the Great Lakes region Tuesday night and bring its own reinforcing cold front through the region. Precipitation on Tuesday is expected to be primarily rainfall, with a few pockets of wintry weather possible at the highest elevations immediately at the onset Tuesday morning, and then again towards the late afternoon as temperatures start to cool. Tuesday night, we expect a switch to rain showers. As temperatures continue to fall through the night, coverage of snow showers is expected to increase from west to east across the region. Gusty winds are expected behind the system on Wednesday, along with some lingering isolated to scattered snow showers across the mountains. Wednesday night into Thursday, high pressure will first be centered over the region, and then shift east to the coast. This will allow for dry conditions, and the start of temperatures beginning to moderate a little. A trend toward milder and wetter conditions will take place Thursday night into Friday. Another trough is expected to be making headway east towards and then east of the Mississippi River valley. A generous fetch of Atlantic and Gulf of Mexico moisture is expected to stream into the area in advance of this system. This will result in increasing chances of precipitation across the region, and rising temperatures. Near the beginning of the precipitation, there may be a few pockets where the low level thermal profile may support some wintry precipitation. Temperatures during this portion of the forecast will start around five to ten degrees above normal on Tuesday, five degrees above normal for on Wednesday, near normal Thursday, and five to ten degrees above normal for Friday. Confidence in the above weather scenario is moderate. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 640 PM EST Friday... Generally poor flying conditions are expected tonight into Sunday morning, with gradually improving conditions expected thereafter. Low pressure moving across the region this evening into tonight will result in widespread IFR/LIFR ceilings as well as pockets of IFR visibility. Rain will diminish this evening into tonight. This will allow the low clouds to break up from time to time, only to fill in again after a short while. Areas of IFR fog and drizzle will form tonight into Saturday morning, especially across the mountains where the ceilings intersect with local terrain. On Saturday, winds will shift westerly and increase in speed during the late morning as a cold front passes from west to east across the area. Gusts across higher terrain may reach 25 knots Saturday afternoon and continue to increase into the evening. Expect gradual improvement in ceilings and visibility along/east of the Blue Ridge during late morning into the afternoon in the downslope flow. IFR ceilings will remain in place at BLF as winds shift increasingly northwesterly. Once enough cold air arrives in the west, snow showers will develop in the western upslope areas. Confidence is low to moderate for ceilings and visibilities. Extended Aviation Discussion... Saturday evening into Sunday, the low pressure system will depart offshore, which will result in a continuation of flight restrictions in mountain clouds and snow showers, along with gusty northwest winds - with a return to VFR weather as skies clear in downsloping areas east of the Blue Ridge. Flying conditions should improve back to VFR in the mountains later Sunday night into Monday, and persist into Tuesday, as high pressure arrives from the west. A few MVFR snow showers may be possible Wednesday morning into the western mountains. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...High Wind Watch from Saturday evening through Sunday morning for VAZ015>017-022-032-033. NC...High Wind Watch from Saturday evening through Sunday morning for NCZ001-002-018. WV...None. && $$ SYNOPSIS...NF NEAR TERM...KK/NF SHORT TERM...DS LONG TERM...DS/WERT AVIATION...KK/NF
For frequently asked questions about the Area Forecast Discussion