Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/30/21

Area Forecast Discussion
National Weather Service Binghamton NY
956 PM EDT Fri Oct 29 2021 .SYNOPSIS... Rain showers are moving into the area this afternoon, and will continue through tonight. Scattered showers are expected Saturday, possibly lingering into Sunday. Temperatures will trend cooler early next week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... Drier air continues to hang in tough across areas from I-81 eastward late this evening. As a result, timing of the showers looks a little slower for these locations tonight. Still a few rounds of rainfall are anticipated. Rainfall amounts so far in the watch area are from 1/2 to 1 inch. The HRRR and Hires NAM both bring the heaviest rainfall during the mid and late evening hours with the forecasted totals on track around 1.5 inches. We have received several reports of flooded roadways and flash flood warnings have been issued into the overnight. Turn around don`t drown. The good news is a dry slot is still advancing northward this evening as expected which will lead to more showery rainfall overnight. Previous discussion below. 200 PM Update... Clouds are overspreading in the area with light rain finally starting to work into the western Twin Tiers. A vertically stacked low continues to slowly move northward through the Ohio valley. An occluded front extends from the center of the cyclone (approximately over Ohio/WV/northern KY) eastward to the mid- Atlantic coast. The satellite-derived total precipitable water product indicates a plume of PWATs up to 1-1.5in extending inland towards the center of the low, courtesy of a strengthening low-level jet that is helping us tap into some Atlantic moisture. Models continue to move the main area of steady, moderate to locally-heavy rain through rather quickly this evening. That, along with wind shadowing/downsloping east of the Poconos- Catskills, is supporting the continued downtrending of rainfall expectations for areas along and east of I-81. Expect totals generally under an inch for most of the area, with the burnt of the activity between 00Z and 06Z. That said, steadier, occasionally heavier rainfall will be possible for a longer duration west of I-81 and south of the Finger Lakes tonight. The axis of deeper moisture pivots westward as the low continues to slowly move northward. Meanwhile, the low level jet will cause orographic enhancement as it upslopes against the Allegheny plateau. Thus, rainfall amounts could exceed an inch for the southern Finger Lakes, as well as Steuben, Chemung, and Bradford counties These areas are already very wet and sensitive to additional rainfall; new rain will almost immediately run off into creeks/small streams. That is where there is a bit more concern for a somewhat organized flooding potential, compared to a more marginal threat elsewhere. A Flash Flood Watch has been issues for Steuben, Bradford, and Chemung counties. The stacked low will continue its northward track, moving into western NY and PA into early Saturday. This more northerly than northeasterly track means a dry slot aloft is likely to lift over our region Saturday. Showers can still be expected, but they will tend to be scattered/on- and- off and with limited amounts. Responses to the heavier rainfall, from overnight, will still be ongoing for the main stem rivers. There is a small chance of a couple river points going back to near minor flood stage, but most will stay below. Meanwhile, the persistently high water levels on Cayuga and Onondaga Lake will continue. After lows of mostly 40s tonight, highs of 50s-near 60 are anticipated for Saturday. Stray showers continue through Saturday night with the upper low directly overhead. Chances will be better across our northeastern zones as a low closes off along the mid Atlantic coast and quickly tracks into New England by early Sunday morning. Otherwise, expect lows to drop back into the mid and upper 40s under cloudy skies. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 315 PM Update: Upper level troughing will slowly lift northeast on Sunday (Halloween), with most of the steadier rainfall moving out of the far eastern counties early in the morning. While this may be followed by a few breaks of sunshine, it`ll be brief, with cyclonic flow aloft and weak cool advection with winds off the Great Lakes promoting increased cloud cover and some spotty light showers or sprinkles again in the afternoon as a weak shortwave trough rotates through. Showers will diminish again around sunset, and while a brief shower can`t be completely ruled out in the evening, it will be mostly dry, with seasonal temperatures. An upper trough moving across southern Ontario into Quebec will drop a weak cold front through the area late Sunday night, with additional light showers possible starting after midnight, mainly west of I-81. The front itself will be near the Hudson Valley by Monday morning, with slightly cooler and drier air spreading across the area in its wake. Partly Sunny skies will prevail for most areas on Monday, except for parts of Oneida County, where lake effect clouds will linger. && .LONG TERM /TUESDAY THROUGH FRIDAY/... 315 PM Update: Most of the Northeast and Mid Atlantic will be on the edge of longwave troughing persisting across eastern Canada through the period. This will keep somewhat cooler than normal temperatures in place (highs in the upper-40s to lower-50s, versus the average of middle to upper 50s). No significant precipitation is expected, but occasional light showers are possible as a few weak disturbances roll by. The first one arrives late Tuesday, with lake effect showers lingering in its wake (mainly west of I-81 in NY). Another sharper shortwave rolls through on Wednesday, bringing the chance of showers to most areas (including NE PA) before Noon, with lake effect lingering in NY through the afternoon. Precip may be a rain/snow mix Tuesday night into Wednesday morning, but coverage and QPF will be low, with minimal impacts expected. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... Rain is moving through the region from SW to NE this evening with intermittent IFR restrictions likely at all terminals as it moves through. ELM, ITH, AVP, and BGM will be impacted between now and 3z while it will take till 2 to 3z to get to SYR and RME with restrictions. A few rain showers ahead of the line could impact RME and SYR but will likely not result in any restrictions with how dry the low levels are ahead of the rain. A strong low level jet will also be associated with the rain with BGM, RME, and AVP having the best chance of reaching LLWS criteria. Behind the rain, low stratus will keep Fuel alternate to border line IFR conditions at all terminals with continued rain showers at times through the late morning. With day time heating, cigs will rise a bit but VFR conditions are unlikely at most terminals but AVP where the added benefit of downsloping will help raise the cigs by the late afternoon. Outlook... Saturday afternoon through Saturday night...Restrictions likely as low pressure system finishes moving through the region with scattered showers and fuel alternate to at times IFR ceilings. Sunday through Sunday night...Scattered rain showers and occasional restrictions possible; mainly Central NY terminals. Monday through Monday night...Mainly VFR. Tuesday through Wednesday...Restrictions possible in passing showers, which may mix with snow during the overnight hours. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...Flash Flood Watch until 5 AM EDT Saturday for PAZ038. NY...Flash Flood Watch until 5 AM EDT Saturday for NYZ022-024. && $$ SYNOPSIS...HLC NEAR TERM...HLC/MDP/MWG SHORT TERM...MPH LONG TERM...MPH AVIATION...AJG
Area Forecast Discussion
National Weather Service Caribou ME
917 PM EDT Fri Oct 29 2021 .SYNOPSIS... High pressure will ridge across the region tonight. Low pressure will approach on Saturday and cross the area Sunday. The low will move northeast on Monday. High pressure will build in from the west later Monday into Tuesday. Weak low pressure will pass south of the area Tuesday night into Wednesday. && .NEAR TERM /THROUGH SATURDAY/... 9:17 PM Update: A surface ridge of high pressure covers the area this evening. The ridge will only move very slowly east overnight. The HRRR and SREF continue to hit on the idea that low clouds form very late tonight or early Saturday morning across most of the FA. At this time there is just one small area of clouds in eastern Washington County with a clear sky elsewhere. The temperatures have dropped off rapidly this evening with many of the northern valleys below freezing. Temperatures in some spots have dropped below forecast lows, and have made some adjustments to the hourly temperatures and forecast lows. Temperatures will likely rise very late tonight if the lower clouds materialize. Otherwise, no significant changes are planned. Previous discussion: High pres to the nne will hold on through tonight keeping dry air in place keeping alleviating any cloud cover until the early morning hrs on Saturday. This will allow a clear skies over the CWA through at least midnight or so, until a return flow sets up around the high allowing for llvl moisture to be advected n overnight. The clear skies and cold temps look to be a nice setup for viewing the Aurora later in the evening and later tonight. This will depend on how quickly the clouds move in. The latest visible satl imagery does confirm some some lower clouds setting up in swrn New Brunswick and off off the coast. This cloudiness is shown by some of the high resolution guidance, including the NAMNEST and HRRR, to move into the coastal and Downeast region overnight and then spread as far n as Aroostook County by around daybreak or just before. Temps will drop quickly after sunset w/readings dropping into the upper 20s and lower 30s across the northern 1/2 of the CWA, while central and downeast areas see mid to upper 30s. The exception to this will be the coast where overnight temps remain in the 40s. Given the light ESE flow setting up during the early morning hrs, expecting some fog to set up. Also, given the deep llvl moisture w/ESE flow and drier air aloft, expecting some drizzle near or just after daybreak, especially across the wsw areas(upslope). For Saturday, a coastal front sets up ahead of the low lifting up from the s. The ESE flow is expected to increase w/drizzle and periods of light rain expanding to the n as. Rain will start moving N by the afternoon as the mdl sndgs show the column moistening up w/low pres lifting up into srn New England. Cooler than the previous days with temps running near normal. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... Low pressure cutting west of the area Saturday night into Sunday will bring a period of moderate to heavy rain and above normal temperatures. The heaviest rain is expected from about midnight Saturday night to 8 AM Sunday. Isolated thunder is also possible across Downeast Maine given strong forcing and a few hundred joules of elevated instability. A 60 to 70kt low level jet will also accompany the precipitation, creating breezy conditions along the coast. Gusts in excess of 40 mph are possible along south facing hills and channels of coastal Hancock and Washington Counties. Rainfall amounts will range from just under an inch across the north, to 1 to 2 inches across upslope favored regions of the Central Highlands and into Downeast Maine. Fallen leaves, particularly across Downeast Maine, may lead to clogged storm drains and localized flooding early Sunday morning. A dry slot will quickly work into the area Sunday afternoon; Precipitation will linger longest across the far north, where showers will remain possible Sunday night. Brisk west flow and lingering low level moisture will lead to isolated to scattered rain showers across higher terrain of the North Woods and Central Highlands. Another shortwave will clip northwestern Maine Monday morning, leading to a chance of showers. Cooler air will be slow to filter in behind the low, leading to continuing above normal temperatures with highs in the 50s. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Troughing across eastern Canada and into the northeastern U.S. will favor near to below normal temperatures and an unsettled pattern next week. There will be a few opportunities for areas to observer their first snowflakes of the year, particularly across northern Maine. Dry air aloft Monday night will gradually erode later Tuesday into Wednesday as a subtle shortwave trough moves across the area, leading to a slight chance of rain and snow showers. Uncertainty increases later in the week as most guidance shows a noreaster developing during the period from Thursday through Saturday, but there is little agreement with respect to timing and positioning. The antecedent air mass will generally favor snow across the north and a mix elsewhere if the low tracks close enough to the coast to produce precipitation. Despite the uncertainty, roughly 60 percent of ensemble members from the 0z ECMWF and 12z GEFS have accumulating snow in Caribou by next Saturday evening, November 6th. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: VFR for all the terminals late this evening w/light and variable winds. MVFR/IFR cigs look to set up after midnight for KBHB and KBGR and then spread n into the northern terminals around 09-11Z. For Saturday, IFR cigs for all terminals early Saturday w/some drizzle and fog. Some gradual improvement to MVFR across all the airfields by afternoon. Light ESE wind increasing to 5-10 kts. SHORT TERM: Saturday night into Sunday AM...MVFR early, then IFR with LLWS likely. Rain, heavy at times, with a an isolated thunderstorm also possible. ESE wind 5 to 15 kts with gusts to 25 kts. Sunday PM to Sunday night...MVFR with showers. S winds 5 to 10 kts with gusts to 20 kts. Monday to Tuesday...VFR with WSW winds 10 to 20 kts with gusts to around 30 kts. Tuesday night to Wednesday...Mainly VFR with W winds 5 to 10 kts with gusts to 20 kts. A slight chance of rain and snow showers. && .MARINE... NEAR TERM: NE winds 10-15 kts becoming E tonight over the outer zones, while the intra-coastal zone sees 5-10 kts. Seas will average 2-4 ft. For Saturday, some fog and drizzle early w/rain pushing in from later in the day. E wind increasing to 15-20 kts w/seas building to 4-5 ft. Some gusts to 25 kts are possilbe later in the afternoon over the outer zns. SHORT TERM: A gale is expected across the waters Saturday night into early Sunday morning with seas up to 12 feet and a period of heavy rain reducing visibility. Conditions improve to SCA Sunday afternoon and evening, then fall below SCA late Monday through Wednesday. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Gale Watch from Saturday evening through Sunday morning for ANZ050>052. && $$ Near Term...CB/Hewitt Short Term...MStrauser Long Term...MStrauser Aviation...CB/Hewitt/MStrauser Marine...CB/Hewitt/MStrauser
Area Forecast Discussion
National Weather Service Glasgow MT
812 PM MDT Fri Oct 29 2021 .DISCUSSION... Cold frontal passage this evening has drastically brought a change in airmasses to the area. The tranquil mild airmass was replaced in Glasgow where the temperature dropped 12 degrees in less than an hour and north winds gusted to over 40 mph. Have blended going forecast with HRRR and other Near-term models that are handling this cold front better. Precipitation this evening along the Canadian border may amount to near or over a tenth of an inch, but no snowfall is expected at this time. TFJ Previous Discussion... Several record highs have already been set this afternoon in Northeast Montana, including Glasgow`s 76 (so far, as of 2:30 pm MDT) which breaks the previous record of 74 from 1915. Today`s "heat" will quickly be replaced by colder temperatures tonight and tomorrow as a cold front sweeps through the area. Short term (tonight through Saturday)... The cold front will move through the area this evening, with northwest winds expected area-wide by midnight tonight. Gusty northwest winds will continue through the day on Saturday before beginning to taper off overnight Saturday night and Sunday morning. Rain showers should also accompany the front, with the rain changing to snow generally north of the Missouri River overnight tonight into Saturday morning. There should be just enough moisture left over tomorrow afternoon to pop a few showers for the CWA (and maybe produce a few flakes of snow north) before clearing out tomorrow evening. Longer term (Saturday night through next week)... The northwest winds should continue into Sunday, but be lighter than tonight and Saturday. For trick-or-treat time Sunday night, temperatures will be in the 20s and 30s. As far as the pattern for the extended, Northeast Montana will be caught between a ridge with its axis running from the Pacific Northwest into British Columbia and Yukon Territory in Canada, and a trough near/over the Great Lakes. The net result for the CWA is temperatures generally in the ballpark of normal--or slightly cooler than norms--for late October and early November. Dry weather is also expected to persist once the precip in the shorter range moves out. 97 && .AVIATION... UPDATED 2000Z FLIGHT CONDITIONS: MVFR at times late evening and overnight through Saturday morning. VFR expected again during the day on Saturday. WINDS: Strong North winds this evening occurred at KGGW and KOLF. These will likely affect KGDV and KSDY areas at about 05z but with lighter speeds but a gust to 30 kts is still possible. Look for NW 15-25 kts Saturday. SYNOPSIS: A cold front will exit the area by late tonight. Rainshowers will be brief at KGGW and KOLF this evening. Cloudy but brisk/windy conditions are expected Saturday. TFJ && .GLASGOW WATCHES/WARNINGS/ADVISORIES... Lake Wind Advisory until 10 AM MDT Saturday For Fort Peck Lake for Central and Southeast Phillips...Central and Southern Valley...Garfield...McCone...Petroleum. && $$
Area Forecast Discussion
National Weather Service Green Bay WI
1055 PM CDT Fri Oct 29 2021 Updated aviation portion for 06Z TAF issuance .SHORT TERM...Tonight and Saturday Issued at 234 PM CDT Fri Oct 29 2021 The latest RAP analysis and satellite/radar imagery show a large occluded cyclone spinning over Kentucky/Tennessee, but the cyclonic flow around this low pressure system extends across most of the western Great Lakes. Widespread cloud cover continues to blanket Wisconsin early this afternoon though showers and drizzle have mostly diminished. Partial clearing has occurred over northern Minnesota close to the axis of surface high pressure. Winds have also increased starting around late morning with gusts into the lower to middle 30s. As the low lifts northeast over the southern Appalachians, cloud and wind trends are the focus of the forecast. Tonight...Cyclonic flow will continue across northeast Wisconsin as low pressure lifts northeast towards West Virginia. Subsidence will increase aloft as drier air associated with the upstream surface high/mid-level ridge axis slides slowly east. However, low level northeast flow off Lake Michigan and Lake Superior will likely keep moisture trapped below the inversion, which will favor mostly cloudy skies across the region. Some breaks may develop, like what occurred over Minnesota this morning. Wind gusts to 30 mph may linger over eastern WI as well, particularly in the evening, but will see a general diminishing trend through the night. Lows will range from the upper 30s to middle 40s. Saturday...The low pressure will gradually weaken as it mosies over the central Appalachians. Cyclonic flow will be much weaker than today, and should therefore see dry air have a greater influence. After a mostly cloudy start, statistical and model guidance favor decreasing clouds through the day. With some sunshine, temps will rise into the middle to upper 50s. .LONG TERM...Saturday Night Through Friday Issued at 234 PM CDT Fri Oct 29 2021 Fairly quiet weather expected through much of the long-term portion of the forecast. Temperatures will drop a few degrees below normal and some light lake effect rain and snow showers will be possible, mainly downwind of Lake Superior. Saturday night through Sunday: A very brief/dry surface ridge and upper-level ridge will pass through the area Saturday night. This will effectively keep much of the area dry under mostly clear skies. Late Saturday night into Sunday morning, a fairly strong cold front is expected to pass through the area from west to east. This will usher in colder air for the beginning of the work week along with a few sprinkles or flurries. The increased cold air advection, along with gusty winds just above the surface, will lead to more of a breezy/blustery day Sunday. Latest guidance would suggest that winds may gust as high as 30 mph from the northwest through much of the day. Overnight lows are forecast to drop into the low to mid 30s central/north-central and the upper 30s to around 40 elsewhere. High temperatures will be in the 40s to around 50 for Halloween. Sunday night through Tuesday night: An upper-level closed low will set up across much of Ontario and drift slowly eastward through this time period. The increased moisture associated with this feature along with shortwaves sliding around the periphery, will allow for intermittent chances for light lake effect rain/snow chances, mainly downwind of Lake Superior. The best chances for lake effect will be as the aforementioned waves pass through the area; however, the exact timing will be difficult to determine this far in advance. Overall moisture doesn`t look overly impressive, but may result in some minor accumulations across north-central. Again, this will depend on overall wind direction and the amount of moisture that wraps through the area along with the time of day. Temperatures will be below normal with lows dropping into the upper teens and 20s. High temperatures will be in the upper 30s to around 40. Rest of the extended: A surface ridge is expected to build across much of the area through this time period, which will likely lead to lower chances for any precipitation as moisture will be limited. Depending on final wind direction, some continue like lake effect precipitation or ,at the very least lake effect cloud cover, may still impact north-central Wisconsin. Temperatures will remain below normal with overnight lows forecast to be in the upper teens to mid 20s. High temperatures will be in the upper 30s to low 40s. For comparison, average high temperatures for this time of year are around 50 and average low temperatures are in the low to mid 30s. && .AVIATION...for 06Z TAF Issuance Issued at 1055 PM CDT Fri Oct 29 2021 North northeast winds flowing across the Great lakes will keep MVFR ceilings over most of the area tonight through midday Saturday. IFR ceilings are possible north of a Rhinelander to Iron Mountain line. Clearing is expected Saturday afternoon which will continue into the evening hours. MVFR ceilings could return late Saturday night. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......Cooley AVIATION.......RDM
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
647 PM CDT Fri Oct 29 2021 .SHORT TERM...(This evening through Saturday night) Issued at 245 PM CDT Fri Oct 29 2021 Two concerns in the short term are the potential for dense fog tonight/Saturday morning and then the timing of a cold front Saturday afternoon and it`s potential implications for afternoon temperatures out toward Alexandria and Morris. Low that brought us a soggy Thursday is still down in the Ohio Valley, but we`ve been seeing a surface ridge axis push in from the Dakotas. Last night, we saw fairly widespread dense fog from north central into western MN and as this ridge axis crawls east, expect a similar result under the ridge tonight from roughly Redwood Falls and Little Falls over to the first tier of counties in western WI. Dewpoints this afternoon are up near 40, so our crossover temps will be easily achievable. Basically, once we start seeing areas drop into the 30s, we`ll start seeing fog form. HREF probs for vis under 1/2 mile is up at 75% along the I-35 corridor, so confidence is pretty high we`ll see fog. Held off on an advisory though as there`s uncertainty with how far east the threat will be in WI given the potential for stratus to be coming back west out of central WI, with areal extent of dense fog in MN uncertain. Still if you`re in eastern MN, it`s best to plan on a foggy start to your Saturday. For Saturday, it will be our last warm day before a cold front arrives in the evening, bringing our first prolonged stretch of below normal temepratures this Fall. The HRRR shows temperatures dropping a good 10-15 degrees in the 2 hours post FROPA, so if the front comes in faster than currently forecast, it could end up being several degrees cooler than forecast up in Morris and Alexandria. Did nudge down highs slightly in eastern MN and western WI as potential warming may be lost for much of the morning as we burn off the morning fog/stratus. .LONG TERM...(Sunday through Friday) Issued at 245 PM CDT Fri Oct 29 2021 If you like northwest west, highs in the 40s and lows in the 20s, you will love the weather next week. We`ll see CAA through the day on Halloween, but after that, little in the way of airmass change is expected the rest of the week. We`ll be in north to northwest flow, generally to the west of an upper low over the Great Lakes. So in place where high pressure likes to reside at the surface. The one thing that could be a bit different from what the NBM populated with is the potential for more cloud cover than currently forecast Monday through Wednesday as we remain in the cyclonic mid-level flow of the eastern NOAM trough. We may also be able to scare some light precip out of the clouds, but it would be nothing more than sprinkles/flurries. This quiet weather looks to have some staying power as well, with mean h5 heights from the EPS not looking to support much in the way of active weather until after the 10th of November. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 647 PM CDT Fri Oct 29 2021 Main concern tonight will be fog, which is most likely to develop along a corridor centered N-S from RST through MSP and toward DLH. Some of this could be dense in spots with prolonged LIFR conditions. This will likely lift into a low stratus deck in the morning and mix out by late morning/early afternoon. A cold front will move in late in the period and reach I-35 right around 00Z with gusty northwest winds following frontal passage. KMSP... Fog, possibly dense, expected to develop after 09Z or so and will be most dense around sunrise. This will burn off/lift through the mid morning hours. Cold front will be very close to MSP by 00Z. /OUTLOOK FOR KMSP/ Sun...VFR. Wind NW at 10G20 kts. Mon...VFR. Wind NW at 10-15 kts. Tue...VFR. Wind NW at 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ SHORT TERM...MPG LONG TERM...MPG AVIATION...DPH
Area Forecast Discussion
National Weather Service Blacksburg VA
1008 PM EDT Fri Oct 29 2021 .SYNOPSIS... A deep upper-level low pressure system centered over far southwest Virginia will meander/drift very slowly north- northeast through Saturday then begin to move a bit more quickly to the northeast Sunday and then lift out of the area Monday. The presence of the upper low will keep clouds and showers across the region through the weekend. However, precipitation will decrease in coverage and intensity steadily through the weekend. Temperatures will remain near seasonal normals in the 50s and 60s for maximum readings with minimum readings remaining above normal mostly in the 40s. && .NEAR TERM /THROUGH SATURDAY NIGHT/... As of 1007 PM EDT Friday... ...Our upper low continues to spin over the region leaving continued chances for showers and cloudy conditions through the weekend... Not much change to the current forecast package with just some minor adjustments in regards to precipitation chances tonight and visibility concerns. Our deep closed upper level low continues to spin over our region tonight with a slow drift to the north and east by the start of the weekend. This will keep shower chances in place especially in areas west of the Blue Ridge overnight into Saturday. Activity will remain light with the heaviest precipitation remaining over the ridges of of the Alleghany Highlands, Greenbrier Valley, Mountain Empire, and western North Carolina region. Moisture will continue to wrap around the upper level low before it`s departure sometime late Saturday night into the day Sunday. Once again coverage will be scattered and sporadic as in pinwheels through the area. No washouts are expected for the start of the weekend with some locations especially out east of the North Carolina and Virginia Piedmont getting away totally dry. Besides the shower chances, the concern for fog remains overnight into Saturday morning. Coverage will remain patchy with the highest confidence per hi-res guidance across the Greenbrier Valley and Alleghany Highlands south toward the New River Valley and western North Carolina mountains. Visibility in these areas could drop below 3 miles with improvements not until mid Saturday morning. Overnight lows tonight will remain on the chilly side of things with low to mid 40s in the mountains to around 50 out east. SOme of the sheltered valley locations such as Burkes Garden could dip into the mid to upper 30s for a short period of time. Temperatures will remain tampered Saturday due to the wedge. CLouds and spotty shower chances will keep most locations in the upper 50s to low 60s. If we do get any sunshine similar to what we saw today temperatures will likely be bumped up by 2-4 degrees getting us into the low to mid 60s. Confidence remains low though as the closed low sits overhead. Moderate confidence remains in the near term period. Previous Discussion... The unsettled weather will continue through Saturday as an upper low lingers. The deep vertically stacked closed upper low across the region will drift northeast through Saturday. Mostly cloudy conditions with scattered showers will continue tonight into Saturday. The HighresW- ARW,HRRR and RAP were similar with the unsettled weather tonight. The coverage of showers will increase this evening and overnight in the north and especially the west as wrap around moisture returns with low drifting to the north. The dry slot will shift east of the area with time. Areas of fog will develop tonight into Saturday morning. Overnight low temperatures will range from the upper 30s in the mountains to near 50 degrees in the Piedmont. Low pressure drifts just to the north of the area Saturday. High temperatures Saturday will vary from the upper 40s in the mountains to the mid 60s in the piedmont. Moderate confidence in the Near Term Forecast. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 100 PM EDT Friday... By the start of Saturday night, the center of the slow moving closed upper low is expected to be located somewhere between the western PA and central VA, heading northeast overnight. As it does, we are expected low level winds to veer northwest and increase in speed. By Sunday morning, a well defined northwest flow pattern is expected to be in place across the region. This will yield downslope compression across the Piedmont of VA and NC with limited cloud cover. Over the mountains, especially those of southeast WV, south into northwest NC, we can expect cloud cover and scattered rain showers. As Sunday progresses, drier air advection will allow the cloud cover and showers to decrease in coverage as the day progresses. While winds are expected to become gusty, they are also expected to remain below Wind Advisory levels and stay gusty into and through Sunday night. Heading into Monday, winds will be on the decrease as cooler high pressure arrives across the region. This high will continue across the area, but upstream, a cold front will move south into the Ohio Valley and spill some of its associated cloud cover into northern sections of the region. Temperatures during this portion of the forecast will trend milder each day with low temperatures about ten degrees above normal and high temperatures around normal on Sunday and around five degrees above normal on Sunday. Confidence in the above portion of the forecast is moderate to high. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 100 PM EDT Friday... During this portion of the forecast, a closed upper level low will spin across southeast Canada. Its overall position and extent to which its associated trough axis digs south into the eastern U.S. varies from model to model. While these differences increase the most by the end of the week, for Tuesday into Wednesday we expecting the following transition. A cold front over the Ohio River Valley will head southeast and cross our region. There is some model disagreement on how much moisture/precipitation will be associated with it. Wednesday night into Thursday, the differences start to increase. The GFS keeps a more progressive pattern across our region, but its European and Canadian counterparts offer an upper low that amplifies south more, keeping the front across the area, and reinforced by increased moisture from the south and southern stream shortwave trough caught up with the tail of the upper trough. By Friday, either the area remains near normal with a nearly zonal flow across the area, south of the Canadian low, or much colder air will be spilling into the area in association with the upper trough axis of the Canadian system still equatorially displaced across the area. Our forecast has been favoring the colder and wetter solutions of the European and Canadian solutions, and we will not deviate far from our ongoing forecast without just evidence to support a major change at this time. This colder and wetter solution places scattered rain and snow showers across the mountains Wednesday into Thursday. Temperatures during this portion of the forecast are expected to trend from near to slightly above normal on Tuesday, to near or slightly below normal conditions, by Friday. Confidence in the above weather scenario is low. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... As of 735 PM EDT Friday... Slowly northeastward meandering upper low will keep unsettled aviation conditions through the Taf period. Vertically stacked upper low over far southwest Virginia will drift slowly north-northeast into central West Virginia into Saturday.Unsettled conditions will continue with BKN-OVC clouds west and SCT-BKN clouds east along with scattered to numerous showers west and widely scattered showers east. Wrap around moisture will result in an increase in precipitation west tonight into Saturday,and in the east by Saturday afternoon. Ceilings...Mostly MVFR to IFR ceilings expected through the period west of the Blue Ridge overnight and Saturday morning trending more toward MVFR Saturday afternoon. IFR-LIFR ceilings expected across the higher terrain of the west. Visibilities...Generally VFR east to MVFR west with just scattered clouds and limited showers east with scattered -RA/-SHRA west increasing overnight/Saturday morning. Some IFR- LIFR visibilities can be possible at times across the higher terrain of the west. Winds...Southwest to West winds 5-8 mph will become West to Northwest through the day Saturday 5-10 mph. Moderate Confidence in Ceilings,Visibilities, and Winds during the Taf Period. Extended Aviation Discussion... The upper low will begin to move out of the area Sunday with improving aviation conditions expected. The western areas may see some periods of MVFR ceilings Sunday into early Monday, but most areas should return to VFR conditions by Monday and into Tuesday. The next sub-VFR producing weather system will likely arrive late Tuesday into Wednesday. MVFR/IFR rain and snow showers will be possible in the west Thursday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...RAB NEAR TERM...ET/KK SHORT TERM...DS LONG TERM...DS AVIATION...KK/RAB
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
754 PM MDT Fri Oct 29 2021 .UPDATE... Issued at 738 PM MDT Fri Oct 29 2021 Broad upper trof over northern Rockies is moving toward the northern Plains this evening, as upper ridge is flattened and pushed to the east. Strong cold front is draped from low over northeastern MT across southwestern MT. Front will move across the forecast area after midnight, with very gusty northwest winds and colder temperatures behind it. Although satellite images show increasing clouds moving toward the area, UNR 00Z sounding is very dry, so precipitation will develop behind the front in the cooler air. && .DISCUSSION...Saturday Through Friday Issued at 151 PM MDT Fri Oct 29 2021 As the upper trough approaches the region, surface trough and cold front will begin crossing the Dakotas early Saturday morning. Northwesterly winds will become strong on Saturday, 20 to 30 mph with gusts up to 40 mph. Forecast winds only marginally meet Wind Advisory criteria, so will forgo issuing headlines for now. Highs will range from the lower 40s across northeastern WY to the upper 50s across south central SD. Models have continued the trend of later precip and less of it. Deterministic NAM and GFS keep best lift within the dendritic growth zone well south of our CWA, across WY/NE. Furthermore, ensembles show generally less than a 50% chance of exceeding 1 inch of snow over the Black Hills, and little to no chance of exceeding 3 inches, which is down from yesterday`s runs. Some light snow accumulations will be possible over the southern Hills/foothills in the area of convergence; additionally, the band of snow may skirt portions of northeastern WY/southwestern SD. As cold air continues to sink into the region, cooler temperatures will persist into early next week. Highs will be in the 30s/40s, with lows in the teens/20s. Chances for precipitation remain low. && .AVIATION...For the 06Z TAFS Through 06Z Saturday Evening Issued At 740 PM MDT Fri Oct 29 2021 High clouds are beginning to move into the area this evening. Smoke from a prescribed burn in the southern Black Hills could still reduce visibility at RAP this evening, but visibility will improve after winds shift to the southwest. A cold front will move across the area after midnight with MVFR/local IFR ceilings developing behind the front. Some light rain/snow is possible over northeastern WY, the Black Hills, and southwestern SD starting Saturday afternoon. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ Update...55 DISCUSSION...Pojorlie AVIATION...55