Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/30/16

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
500 PM MST Thu Dec 29 2016 .AVIATION... 00Z TAF CYCLE VFR conditions are expected at TAF sites and northward through the next 24 hours. Moisture advected by the subtropical jet could result in isolated showers over the southern fringe of the forecast area (mainly in the mountains) tonight and Friday morning. Rain and snow showers will move into the state from the west Friday evening as an upper level trough approaches from southern CA. 44 && .PREV DISCUSSION...308 PM MST Thu Dec 29 2016... .SYNOPSIS... Cloudiness mostly of the high, thin variety will continue to stream northeast across much of New Mexico tonight. The thickest cloud cover will be found across the southern part of the area and could yield a few rain or high elevation snow showers near Ruidoso but precipitation amounts will not be significant. Temperatures will rebound on Friday ahead of the the first in a series of quick hitting weather disturbances that will impact the area Friday night and Saturday. Another system will move through New Year`s Day with more rain and snow especially favoring western and southern areas. Confidence is growing in a significant change to colder and more impactful wintry weather the first full week of January. && .DISCUSSION... Looks like 2016 will end much like it began-- rather active. While we`re not looking at blockbuster mountain snowfalls with any one individual system, the cumulative totals do look pretty good. Anticipate at least minor to moderate winter wx travel impacts for higher elevations of western and northern NM as well as the San Juan Basin-Four Corners Friday night- Saturday, and near/above 6500 feet for NYD with the focus shifting more into central/southern areas. 12Z model guidance as well as latest HRRR still insist keeping measurable QPF south of our area through 12Z Fri. Boundary layer remains very dry across our southern zones and best low level moisture/WAA advection above the NW-SE oriented frontal zone appears to extend from SE AZ to NM bootheel to near KELP and not expected to shift much farther north. Few very weak echoes across southern Catron, southern Socorro and southwest Lincoln counties evidence of top down moistening. Cannot completely rule out isolated measurable precip for areas near Ruidoso/Dunken tonight but not going to be significant. Already seeing western edge of cirroform cloud shield shift eastward over southeast AZ. Lee-side surface trough quickly reestablishes on Friday as mid- level westerlies strengthen ahead of a shortwave trough, formerly the system west of Baja, that has now trended slower and wetter/snowier for some areas Friday night into Saturday. Increasing precip chances after sunset Friday with main window from about 06Z Sat to 00Z Sun. The GFS and ECMWF are now more bullish with QPF in the Four Corners Friday night where 1-2 inches of slushy snow very possible for Farmington- Bloomfield-Aztec especially if GFS verifies. Other feature of interest will be a secondary surge of cold air into NE/EC New Mexico early Saturday that could set up favorable upslope and enhanced region of precip as upper wave translates eastward. Precip types here do look tricky with potential for sleet/freezing rain. Otherwise, thinking snowfall totals broadly in 2 to 6 inch range near and above 6500 feet with higher west facing slopes favored. The GFS is noticeably colder than the NAM at 700mb with this wave and wet bulbing effects could come into play and be rather significant at locally lowering snow levels. The NYE wave should exit Saturday evening with precip coverage trending downward from late evening to several hours after midnight but the break will be short-lived. An even stronger and colder shortwave/upper low will cross the area NYD. 12Z models maintain previous trend of tracking the primary low center toward NM bootheel by 00Z Mon but a nice deformation precip band sets up east of the Divide toward the RGV late Sunday before the wave pivots east- northeast Sunday night. The Upper Gila and SC ranges could do quite well, as well as the Sandia/Manzanos,and 700mb temps of -2 to -4 will allow accumulating snow down to 6500 feet if not a bit below. Monday/Tuesday next week transitions to a much winder/mountain wave/westerly orographic pattern with Arctic air making a return visit to eastern NM by Tuesday/Wednesday and dominating much of next week. Looks messy with precip types in the east and west facing slopes of the northern mountains should do particularly well with snowfall. KJ && .FIRE WEATHER... For just a short while longer, NM will remain between weather systems with a deep upper level trough over the eastern U.S. and a cut-off low over the open waters of the eastern Pacific. High level moisture is pushing northeastward ahead of the Pacific low and into NM, giving widespread high clouds over much of our forecast area. These will gradually drift out of the area overnight, but lower- based clouds will filter into the southern sections of NM, largely south of the ABQ fire weather forecast area. Overall, tonight`s low temperatures will not stray too much from the observed lows of last night and early this morning, and RH recoveries will be excellent in most zones, the exception being the Sangre de Cristo mountains where much lower dewpoints will impede recoveries. By Friday, the aforementioned Pacific low will have made landfall into southern CA. Variable cloudiness and shifting winds over NM will offer some temperature changes, primarily in the northeastern plains of the state where readings will escalate some 10 to 15 degrees due to a lee side trough and the consequential downslope breezes. This will push all zones at or above normal temperature- wise with the largest departures in the northeastern plains. Despite some stronger breezes along the highlands-high plains interface, smoke dispersion/ventilation rates will remain poor on Friday. Also of note, the best subtropical moisture is projected to stream south and east of NM through Friday, and thus it will not be until Friday night and Saturday when precipitation will be observed. The remnants of the weakened low will cross NM Friday night into Saturday, and as precipitation spreads from west to east, snow accumulations of any significance will generally be confined to higher elevations with lighter amounts in the valleys and lower elevations of northern and central NM. Still, wetting liquid equivalent amounts of 0.10 or greater seem plausible for many central to western zones Friday night into Saturday. In addition to the precipitation, a cold front will back into northeast NM Saturday, disrupting the above normal temperature trend. Another low pressure system will arrive on the heels of the Friday night and Saturday system, and this second disturbance should weaken some as it crosses the southern border of NM during the daytime Sunday. Cooler air will filter into western NM Sunday with a second shot of rain and high elevation snow leading to a few more inches of accumulation upon the highest peaks. Winds strengthen into Monday as a perturbed and stiff westerly flow aloft sets up. Slightly below normal temperatures in the central to western zones will persist along with slightly warmer than average readings in the eastern plains of NM Monday. Any precipitation would be focused over the north central to northwestern zones, and ventilation is currently advertised to be fair amidst the stronger westerlies. A quasi-similar regime would hold through Tuesday before the flow buckles on Wednesday, spilling much colder air into NM. Despite some periods of breezy to occasionally windy conditions next week, critical fire weather is not forecast at this time. 52 && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Caribou ME
1017 PM EST Thu Dec 29 2016 .SYNOPSIS... Low pressure developing off of the Delmarva this afternoon will rapidly intensify as it lifts into the Gulf of Maine tonight. It will cross central sections of the state overnight. A weak area of low pressure will cross the region Saturday night into Sunday morning. && .NEAR TERM /THROUGH FRIDAY/... Update 10:15 pm: Have raised snow accumulation for zone 15 to the north of Bangor based on developing banding and for zone 32 based on latest expected storm track. Will extend winter storm warnings into both of these zones. Sfc low developed this mrng off the Delmarva and has dropped 10mb in 4 hrs. Greatest pressure falls are centered to the northeast of the low cntr and over Nantucket MA at this time. Latest RUC and NAM are slightly too weak with sfc low as of 18z this aftn. Snow has mvd into wrn parts of CWA this aftn and wl continue thru the ovrngt. Hires models are hinting that sfc low wl mv acrs Houlton by 12z Fri, dropping an average of 22-24 mb in 12 hours. This is in agreement with NAM and GEM. Latest GFS tracks low west while EC tracks the low east, thus have gone with the compromise and hv allowed for low to mv ovr Houlton Fri mrng. This keeps all snow north of a Dover- Foxcroft to Danforth line. Warm air wl be drawn in on strong srly flow ovrngt switching pcpn ovr to rain as far north as Bangor to Calais this evng. Locations in the Upper Penobscot Vly will likely see a rain-snow mix tonight. May see svrl hours of sleet in southeast Aroostook for a time right around daybreak, enough to drop the snow totals but still retaining warning amnts. Snow should be fairly close to a 10:1 ratio and hv reduced areas of blowing snow back to patchy for the overnight. As low tracks north thru the state, expect gusty east winds thru midnight to near 30 MPH. Winds will back around to the northwest as the low slides into New Brunswick toward morning with gusts increasing to near 35 MPH in the afternoon. This may result in scattered power outages through tomorrow. Further to the south, coastal zones will likely see SW winds exceed 40 MPH around midnight and into the morning hours therefore will continue with High Wind Warning. Expect temps to rise during the course of the nighttime hours tonight before dropping acrs the nw after 07z as low tracks acrs cntrl sxns. Lopres wl pull twd the Gaspe Peninsula tomorrow aftn with snow showers ending drg the aftn. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... The models are in good agreement through the period. A low tracking northeast across eastern Quebec will bring a few lingering snow showers to northern Maine early in the period. By Saturday morning higher pressure will briefly ridge into the area, another frontal system will move into southwestern Maine Saturday afternoon. Saturday evening the warm front will across western Maine into Downeast Maine. The frontal system will track across the state overnight and by Sunday morning the front will be along the Maine and New Brunswick border. Higher pressure will once again build across the region, as the front moves into New Brunswick and will remain through the end of the period. Loaded a blend of the GFS/GEM/NAM/ECMWF to smooth out the minor differences in the models. Loaded NAWAVE4 for seas in the coastal waters. Loaded windgust by factor tool. For QPF used GFS. && .LONG TERM /MONDAY THROUGH THURSDAY/... The extended models are in good general agreement, a low over the Gulf of St Lawrence may bring a few lingering snowshowers to northern Maine otherwise higher pressure will build across the area. The GFS and ECMWF differ about 6 hrs on timing of the next system moving into western Maine. The GFS moves it in around 2 AM Tuesday morning, the ECMWF around 8 AM. Both models move it to the central portions of the state by mid day, and slowly moves it through the state. Finally moving it to New Brunswick Wednesday afternoon, higher pressure will briefly build in, but will be moved out Wednesday evening as a secondary cold front moves through the state. By Thursday morning the front will be east of the area. High pressure will ridge across the area and will remain through the end of the period. Loaded a blend to smooth out the minor differences in the models. Loaded NAWAVE4 for seas in the coastal waters. Loaded windgust by factor tool. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... NEAR TERM: MVFR restrictions will give way to IFR this evening as pcpn moves in from the west. Snow expected for terminals north of HUL. May see several hours of -SNPL at HUL around daybreak. BGR will likely see -RASN after 00z then becoming -RA overnight before going back to -SHSN after 12z. BHB will see -RA remainder of TAF valid time. LLWS expected after 00z through 09z tonight as southeast winds increase to between 45-50kts out of the southeast. Confidence too low to include at BGR. SHORT TERM: VFR conditions with a few lingering snowshowers across northern Maine early in the period. IFR conditions in snow will move across the region from the Saturday night into Sunday morning. VFR conditions will return to the area by early afternoon Sunday and will remain through early morning Tuesday. Conditions will deteriorate to IFR in snow at all sites by late morning Tuesday and will remain IFR through the end of the period. && .MARINE... NEAR TERM: Storm warnings will be in effect this evening through tomorrow afternoon. Seas will range from 12-20 feet in swrly swell. SHORT TERM: A small craft warning will be in effect through the period with near gale force winds early. Winds and seas will subside below SCA briefly early Sunday evening, however will build again above SCA by late evening. && .TIDES/COASTAL FLOODING... Splashover is possible tonight around the time of high tide. High tide at Bar Harbor is 1107 pm tonight. A storm surge of 1-2 feet is possible. The astronomical tides are not all that high, but some minor splash over is possible around the time of high tide. Minor splash over is also possible around the time of high tide Friday morning. A coastal flood advisory has been issued for the high tide late this evening. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Winter Storm Warning until noon EST Friday for MEZ002-005-006- 011-015-032. Winter Storm Warning until 4 PM EST Friday for MEZ001-003-004- 010-031. Winter Weather Advisory until 7 AM EST Friday for MEZ016-017. High Wind Warning until 1 PM EST Friday for MEZ029-030. Coastal Flood Advisory until 1 AM EST Friday for MEZ029-030. MARINE...Storm Warning until noon EST Friday for ANZ050>052. && $$ Near Term...Mignone
Area Forecast Discussion
National Weather Service Wilmington OH
912 PM EST Thu Dec 29 2016 .SYNOPSIS... An upper level trough will move east through the Great Lakes tonight, bringing snow showers and snow squalls to the region this evening. Snow showers will diminish on Friday, as high pressure builds into the southeast states, extending northward into the Ohio Valley. A series of low pressure systems will move northeast through the region from Saturday through Monday, bringing additional chances for precipitation. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... With initial batch of snow showers east, and shallower moisture arriving, have reduced pops and intensity of snow showers through tonight. Added flurries that will fall from a shallow moist and unstable layer between about 2500 to 5000 feet agl. Previous discussion: The middle Ohio Valley is currently located in a regime of deep- layer WNW flow. While there is evidence of a weak surface trough, along an axis from roughly Port Huron MI to Springfield IL, this trough is not well defined -- just a slight 20-30 degree wind shift and little change in boundary layer air mass. There is also very little going on at 500mb and above, with the upper jet curving well south of the region, and no real indication of notable forcing further aloft. The features to monitor are located in between, showing up nicely on recent RAP13 runs. A compact shortwave at 700mb is currently moving through northern Illinois, and will move WSW across Indiana and Ohio over the next few hours. As this occurs, there will be a rapid cooling/moistening of the 850mb-700mb layer, which will have a pronounced effect on weather conditions over the region -- a significant deepening of the boundary layer. The clear skies observed over much of the forecast area this afternoon will be quickly replaced by thick convective stratocumulus in a very-well- mixed near-surface environment. The genesis region for this change in atmospheric conditions is presently over NE Illinois, as evidenced by the curved band of clouds on visible satellite and the developing 20-30 dBZ echoes between Chicago and Springfield -- and, to note, not the unidentified non-meteorological echoes over southern Indiana. Recent HRRR runs / 12Z WRF-NMM / 12Z SPC-WRF runs suggest that a broken band of snow squalls will cross the ILN forecast area from WNW to ESE between 21Z and 02Z, with continued scattered snow shower activity following behind. Current observations suggest this may be a little too fast, maybe by an hour or so. As this activity crosses through the area, the mixed layer will extend far enough aloft to support wind gusts in the 30-35 knot range, with steepening lapse rates that will allow for convective instability through about 8kft AGL / 700mb. This instability will overlap the dendritic growth zone with increasing relative humidity within the -12C to -18C layer, resulting in efficient snow production for what should be a relatively brief period of time. Across multiple model datasets as viewed in BUFKIT, values for these parameters -- such as low-level lapse rates, wind speeds, SBCAPE, and DGZ depth/RH -- fit nicely within WFO ILN (Kurz/Haines) research from verified snow squall cases. To no surprise, this is also indicated on the WFO BTV snow squall parameter (Banacos/Loconto/Devoir). Despite this, there are a few factors that might keep this from being one of the truly high-impact snow squall events -- the lack of a classic arctic front to focus low-level convergence, relatively un-hazardous (warm) antecedent conditions, and the lack of upper support (shortwave or PV anomaly) to increase lift. The ultimate expectation is that most of the CWA will be impacted by the initial broken band of snow showers / snow squalls, some of which may become strong enough to support hazards of rapid accumulations and loss of visibility. Once the initial band has passed, RH in the dendritic growth zone decreases significantly with southwestward extent, and continued snow shower activity will be much more likely further to the northeast (especially along and north of a rough line from Richmond IN to Chillicothe OH). Forecasting accumulations for this sort of scenario is difficult, as some locations impacted by the squalls or repeated snow showers could quickly pick up a half inch (possibly up near an inch) while other locations (especially in the southwestern sections of the CWA) may receive little to no accumulation. An overall diminishing trend in snow shower coverage and wind gust intensity is expected after 06Z, with continued cold advection heading into Friday morning, and lows in the middle to upper 20s. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... A few persisting snow showers or flurries may occur on Friday morning in central Ohio, but overall, conditions are expected to dry significantly -- with clearing skies from west to east over the course of the afternoon, with rising heights. Some wind gusts of 20-25 MPH may continue through the day. A switch to warm advection will allow temperatures to slowly rise on Friday night into Saturday morning, ahead of the next low pressure system moving through the Great Lakes. With a southern stream of moisture helping to develop precipitation across the area, a mix of rain and snow is expected to develop -- favoring rain in the ILN CWA on Saturday afternoon, but perhaps switching back to snow again as temperatures cool Saturday evening. Though a cold front will be moving southeast into the area, it will eventually stall on Saturday night and fail to make it south into Kentucky. && .LONG TERM /SUNDAY THROUGH THURSDAY/... A weak cold front will move south/southeast through the area early Sunday morning. Models have hinted at some moisture/light precipitation lingering along/south of the Ohio River behind the front Sunday morning. This may allow for a few light rain/snow showers in southern parts of the FA during the morning hours before sufficient surface warming changes all/any precipitation to rain. As the frontal boundary stalls just south of the FA during the day Sunday, overrunning moisture is expected to work back northward as the front begins to pivot back north into the Ohio Valley by Sunday night into Monday. Although some of the details still differ slightly, global models have come into better agreement regarding strength/amplitude and timing of a S/W which will move from western Texas early Monday into the Ohio Valley Tuesday morning. At the surface, a strengthening low pressure system in the central Plains will push toward the Ohio Valley, and as such, expect that temperatures will trend well above normal Monday even as WAA-induced scattered showers linger in the FA. Have maintained likely PoPs Monday evening into early Tuesday as the system moves through the region. Colder air will begin to slowly build back into the area late Tuesday into Wednesday as a cold front moves through and the upper level trough continues to dig southward into the upper Midwest and Great Lakes region. Temperatures may even trend below normal towards the end of the period as the CAA regime persists in the Ohio Valley. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Snow showers associated with a mid level short wave and low level cold advection will impact TAF sites tonight. Main effects will be at DAY CMH LCK and ILN where MVFR is expected, with lesser impact at CVG and LUK which will probably stay VFR. All sites should become VFR by Friday morning as drier air moves in amid decreasing short wave energy. West winds will be quite strong, with gusts near 40 knots to start, subsiding somewhat Friday while gusts remain over 20 knots. OUTLOOK...MVFR ceilings and visibilities are possible Saturday afternoon into Monday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hatzos NEAR TERM...Coniglio/Hatzos SHORT TERM...Hatzos LONG TERM...KC AVIATION...Coniglio