Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/02/20

Area Forecast Discussion
National Weather Service La Crosse WI
1049 PM CDT Thu Oct 1 2020 .SHORT TERM...(Tonight through Friday) ISSUED AT 144 pm CDT Thu Oct 1 2020 Currently, water vapor imagery showing a fairly vigorous PV-anomaly rotating southeastward across our area/Great Lakes region. Radar showing quite a bit of shower activity across our area with this feature and very cold cyclonic flow/steep low level lapse rates overhead. Visible satellite also showing expansive amount of cumulus/stratocumulus extending across WI/MN/southern Canada. Temperatures as of 1 PM were unseasonably chilly with readings in the 40s/50s. Look for this mid-level wave and surface cold front to push southeast of the area by this evening but clouds could be stubborn to clear as high pressure builds in. RAP model does show a slow decrease in 925mb RH however and forecast soundings show this as well. With 925mb temperatures falling to near 0C, look for good radiational cooling where breaks occur in the cloud. As such, will keep Frost Advisory going as is (1 am to 8 am Friday) with lows expected to fall into the upper 20s (central WI), to the lower/mid 30s elsewhere. High pressure drifts across the area Friday with partly to mostly sunny skies expected. Despite sunshine, temperatures will remain chilly with highs only in the mid 40s to lower 50s. .LONG TERM...(Friday night through Thursday) ISSUED AT 144 PM CDT Thu Oct 1 2020 Northwest flow continues through the weekend with another fairly strong PV anomaly dropping southeast into the area Saturday/Saturday night. Strongest part of this energy.surface low appears to be south of the forecast area per latest NAM/GFS but plenty of cool cyclonic flow aloft over us, so expecting scattered showers as a result. Otherwise, continued colder than normal with highs only in the 40s/lower 50s. High pressure builds back in for Sunday for dry but continued chilly conditions. Plan on highs again in the 40s/lower 50s. Warm air advection kicks in Monday on breezy south winds on the backside of the departing high and in advance of a cold front dropping through the Northern Plains. Look for highs Monday in the mid 50s to lower 60s. Latest GFS/ECMWF in good agreement bringing another trough/surface cold front through Monday night into Tuesday. This front looks to come through mostly dry though. Otherwise, plan on highs in the 60s. One last trough/surface low in northwest flow aloft looks to impact the area Tuesday night into Wednesday with squattered showers but then drying/warming taking place Thursday as mid-level ridging amplifies over the central CONUS. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1049 PM CDT Thu Oct 1 2020 VFR conditions are expected through the period. The large area of high pressure over the eastern Dakotas into Kansas will drift east across the area through Friday evening and keep the winds light out of the northwest. The flow aloft will remain north/northwest which will continue to bring in some scattered to broken clouds from time to time for occasional VFR ceilings. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...Frost Advisory until 8 AM CDT Friday for WIZ029-032>034-041>044- 053>055-061. MN...Frost Advisory until 8 AM CDT Friday for MNZ079-086>088-094>096. IA...Frost Advisory until 8 AM CDT Friday for IAZ008>011-018-019-029- 030. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...04
Area Forecast Discussion
National Weather Service Boise ID
814 PM MDT Thu Oct 1 2020 .DISCUSSION...Upper level ridge will continue above normal temperatures, light winds and dry conditions though Friday. Satellite showed smoke across the area though the smoke remains aloft except near local fires. Could see smoke from fires in the West Central mountains on Friday as the flow becomes more northerly. Otherwise, temperatures on Friday will reach about 10 degrees above normal. No update needed at this time. && .AVIATION...VFR. Smoke layers aloft. Patchy valley fog in the mountains overnight. Surface winds: 10 kts or less overnight, increasing to NW 5-15 kts Friday afternoon with the strongest winds to the SE of KBOI. Winds aloft near 10k ft MSL: NW 5-15 kts. Weekend outlook...Mostly clear with smoke layers. Patchy mountain valley fog during the mornings. Breezy conditions over higher terrain on Sunday afternoon. && .PREV DISCUSSION... SHORT TERM...Tonight through Saturday night...Persistent upper ridge through Saturday night, then flattening Sunday as a weak short wave trough and surface cold front come through. The front will have little effect on surface temps but cooling aloft will cause slight destabilization and increased mixing. The mixing will allow smoke layers aloft to get into the lower levels. HRRR smoke model increases surface smoke in Baker County/OR and western Idaho beginning late Friday, but Harney and Malheur Counties will have less smoke. Models develop breezy northwest winds in the Snake Basin Friday afternoon, otherwise light winds through Saturday night. LONG TERM...Sunday through Thursday...The upper level ridge will weaken as a weak cold front tracks across MT on Monday with slightly cooler temperatures, but still around 5-10 degrees above normal. The upper level ridge will rebuild over the region by Tuesday with warm and dry conditions through Thursday. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ DISCUSSION...JDS AVIATION.....AL PREV SHORT TERM...LC PREV LONG TERM....KA
Area Forecast Discussion
National Weather Service Denver/Boulder CO
803 PM MDT Thu Oct 1 2020 .UPDATE... Issued at 759 PM MDT Thu Oct 1 2020 Little change needed to previous fcst. Smoke, mainly from the Mullen fire, will continue to affect the area thru Friday. && .SHORT TERM...(This evening through Friday) Issued at 1230 PM MDT Thu Oct 1 2020 The high amplitude ridge continues to be over the western portion of the CONUS with northwest upper level flow over the region. Temperatures were slightly cooler today behind a cooler flow of easterly winds on the surface in the post-frontal airmass. Dry conditions will continue through Friday with a gradual increase in temperatures as 700 mb temps approach +8-9.5C but still hovering around seasonal normals. The bigger impacts will continue to be the smoke produced by the Cameron Peak and Mullen fires in Larimer county and just across the border in Wyoming. Current wind patterns and HRRR smoke models show another day of extensive smoke cover over the northern and central foothills as well as the lower elevations of I-76 and south. A mixture of near-surface and elevated smoke could hinder some increase in temperatures tomorrow afternoon as well as provide hazardous air quality conditions for sensitive groups. .LONG TERM...(Friday night through Thursday) Issued at 1230 PM MDT Thu Oct 1 2020 No significant changes to the long term. Main theme is continued dry conditions with above normal temperatures and persistent elevated fire danger. Areas of smoke will continue to be an issue at times in the mountains, foothills and adjacent plains. On the synoptic scale, a ridge of high pressure will remain over the west coast, with a northwesterly flow over CO. A short wave trough is expected to pass to drop into the Midwest Friday night into Saturday morning. There is the potential of an isolated shower over the far northeast plains Friday evening as a weak cold front pushes across the area, but that is basically it. Temperatures on Saturday will drop back into the mid/upper 60s. By Sunday however, temperatures will climb back into the 70s. The flow aloft will weaken on Sunday, as the flow aloft transitions to west/northwesterly component. On Monday, the wind will increase over the region and warms up as a weak lee trough over eastern CO generates an additional downslope component along the Front Range. A weak front then pushes across the region late Monday/Monday night but no real impact from this feature aside from a brief period of gusty winds. Tuesday through Thursday, the ridge will spread over the central Rockies. Temperatures will remain above normal with generally lighter winds under the ridge axis. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 759 PM MDT Thu Oct 1 2020 Winds have become light southeast and should go to drainage by midnight. Latest HRRR Smoke indicates some restriction in visibility late tonight through Friday. && .FIRE WEATHER... Issued at 1230 PM MDT Thu Oct 1 2020 There will be elevated fire danger through the middle of next week with continued dry and warm conditions. The biggest potential for red flag conditions will be Monday with stronger winds and very low humidities over mountains, mountain valleys and elevated terrain. Otherwise, the wind will be light which will help slightly offset the persistently dry conditions. Areas of smoke will continue to impact the mountains, foothills and adjacent plains as well. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...RPK SHORT TERM...Bowen LONG TERM...Cooper AVIATION...RPK FIRE WEATHER...Cooper
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
951 PM CDT Thu Oct 1 2020 .UPDATE... 950 PM CDT Some mainly tweaks to the forecast for the remainder of tonight into Friday morning. The Frost Advisory continues for far northern Illinois. The diurnally driven showers have faded with most of the showers on the radar scope now being lake effect driven into far northwest Indiana and far southwest Michigan. These should see a gradual intensification due to deepening cloud layers/increasing cold advection over the warmer lake waters, as well as a better propensity to see isolated lightning. RAP soundings from the Indiana nearshore modified for an average of southern Lake Michigan temperatures in the mid 50s provide lake induced CAPE values of 600-1,000 J/kg. This is down some from earlier RAP/NAM forecasts but still sufficient for moderate showers. Also have noted the updrafts have struggled to remain rooted on the low- level convergent axis across southern Lake Michigan. This may be owing to still stout 850-925 mb wind flow (25-30 kt on KLOT VWP). Most CAMs focus the boundary into the northwest Indiana shore into the overnight and increase the coverage of showers as the now developing mesolow moves into far northwest Indiana. Still a chance far northeast Illinois including the Chicago lakefront gets clipped with this shower activity including around daybreak. The potential for a few waterspouts, including possibly near or into the nearshore, remains for overnight. Otherwise over land, a fairly large cloud area is present across southern Wisconsin into northeast Iowa, associated with a slight enhancement of cold advection around 850 mb. This has kept temperatures and dew points in the mid 40s underneath. These clouds are not locked under a strong inversion or basically any inversion at all using the 00Z GRB sounding as a proxy. That means these could gradually dissipate, but at this time it looks like at least several hours where far northern Illinois should struggle to fall much for temperatures into the early overnight thanks to mostly cloudy conditions. Have nudged up mins a tad but continue with the frost mention and the Advisory, as the back edge of these clouds is expected to move over the area a few hours before daybreak. MTF && .SHORT TERM... 304 PM CDT Through Friday night... Scattered showers will gradually taper over much of the CWA this evening as the attendant shortwave departs. Portions of northwest Indiana will be the exception to this with a lake effect shower event expected to develop this evening into the overnight hours as a favorable northerly fetch develops over southern Lake Michigan. Surface-850 mb temperature differentials of 16-18 degrees Celsius, CAPE values of around 1500 J/kg, and ELs upwards of 30000 ft will be more than enough to support a convective band of lake effect showers that could produce localized rainfall totals approaching 1 inch if sufficient training materializes. Low freezing levels will also support lightning and some small hail/graupel, both of which were already observed within some shower cells that moved across northwest Indiana earlier today. Conditions also remain favorable for the development of waterspouts over southern Lake Michigan tonight, so that will be something to keep an eye on as we head into this evening. Regarding temperatures tonight and the potential for frost: have elected to not make any alterations to the inherited Frost Advisory. While some thinning of the diurnally-enhanced cloud cover will likely take place this evening, additional patches of lower cloud cover appear possible as our region remains on the cyclonic shear side of the upper jet. Forecast soundings indicate some degree of re- saturation taking place as well later this evening as another upstream vort max translates overhead. Given this and the potential for winds to remain ever-so-slightly elevated tonight, the signal for widespread frost doesn`t appear high enough to warrant an areal expansion at this point, but will let the evening shift take an additional look. The lake effect showers will likely continue into Friday morning before diminishing as height rises and associated subsidence slash ELs significantly while a northwesterly wind shift across the entirety of southern Lake Michigan simultaneously reduces surface convergence. Dry weather is then expected the rest of the day as a region of surface high pressure builds in. High temperatures tomorrow should be a smidge cooler than today as the core of a rather cool airmass more fully overspreads the region. For tomorrow night/Saturday morning, the floor on overnight temperatures is certainly lower than it is tonight as the core of the surface high slides overhead and winds go light and variable/calm during the evening. The main questions are how expansive the lingering stratocumulus remains from Friday, and how quickly another round of cloud cover returns ahead of the next incoming system. Should things clear out and remain that way, could envision some locations flirting with the freezing mark. That said, latest indications point to cloud covering continuing to play a role here and may end up holding temperatures up a bit. The offered blended guidance still appears to be a reasonable estimate of things at this time, but we`ll continue to re-evaluate as additional guidance becomes available. Ogorek/Carlaw && .LONG TERM... 237 PM CDT Saturday through Thursday... Unseasonably cool conditions will continue through the weekend, but warmer temperatures are expected for the early to middle part of next week. The only notable chance of rain for the area during the period looks to be late Saturday afternoon and night. During this period, our next upper level impulse will approach the area from the northwest and push another cold front southward across the area by early Sunday morning. While the rain may linger across eastern sections of the area Sunday due to the possibility for more lake effect showers, it appears most areas across IL will begin to dry out by the afternoon. However, breezy northerly winds will make for a chilly afternoon as temperatures remain in the low to mid 50s. Surface high pressure looks to set up over the area Sunday night into early Monday morning. Light winds and clearing skies with this high could once again result in frost potential with lows in the low to mid 30s inland from the lake Sunday night. This surface high is expected to shift to our southeast on Monday, which will in turn allow the winds to shift southerly for Monday and Tuesday. This will help push temperatures back into the 60s for Monday and Tuesday. Another storm system may then impact parts of the Great lakes around Midweek. At this time it appears the primary precipitation threat from this system may remain to our north. However, an associated cold front looks to shift southward over the area by midweek. While this could bring a period of cooler temperatures later in the week, it looks as though it could be short lived, with a return to warm conditions beyond the current forecast period. KJB && .AVIATION... For the 00Z TAFs... 623 PM...Forecast concerns include... Scattered showers this evening. Lake effect rain showers tonight in northwest IN. Lake breeze/northeast wind shift late Friday afternoon. Scattered showers will slowly dissipate through mid evening with lake effect rain showers continuing into the overnight hours in northwest IN and at gyy. The stronger showers may produce brief gusty winds. Once this activity ends tonight...dry weather is expected Friday. Prevailing winds are expected to remain northwest through Friday afternoon and then will shift to the northeast late Friday afternoon or early Friday evening for the Chicago terminals. Prevailing cigs are expected to remain vfr through the period... possibly scattering out Friday afternoon. Brief mvfr cigs will be possible with the rain showers and mvfr cigs are likely over the lake tonight and some of these mvfr cigs will be possible near the Lake Michigan shore...especially toward gyy. cms && .LOT WATCHES/WARNINGS/ADVISORIES... IL...Frost Advisory...ILZ003-ILZ004-ILZ005...3 AM Friday to 9 AM Friday. IN...None. LM...Small Craft Advisory...Winthrop Harbor to Burns Harbor until 1 PM Friday. Small Craft Advisory...Burns Harbor to Michigan City IN until 4 PM Friday. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Marquette MI
746 PM EDT Thu Oct 1 2020 .SHORT TERM...(This evening through Friday) Issued at 409 PM EDT THU OCT 1 2020 WV imagery and RAP analysis indicated an amplified pattern with a ridge over western North America and a trough from northern Quebec to the southern Mississippi Valley resulting northwest flow through the western Great Lakes. At the surface, northerly flow prevailed between a ridge through the Plains and a trough from southern Ontario into northern lower Michigan. With 850 mb temps to around -5C (lake sfc temp near 12C) instability supported scattered to numerous lake effect rain showers. Tonight, continued CAA will drop 850 mb temps to near -7C. Even with some mid level drying, inversion heights remaining around 7k-8k ft with lake induced CAPE values of 300-400 J/Kg will maintain lake the lake effect pcpn. Forecast wet-bulb zero heights also will support a mix or change to snow over inland locations, especially with elevations over 1200 ft. The convective/moisture layer also looks just deep enough to support mainly snow rather than dz/fzdz. Temps dropping into the upper 20s to lower 30s may allow some snow to accumulate to around an inch with some brief slushy roads with slipper spots especially on bridges. Friday, as winds become lighter lake induced troughing and stronger low level convergence is expected to develop focusing the heavier pcpn and greater coverage along or near the shore in Marquette county during the morning. By afternoon, diurnal heating and an even weaker gradient will favor mainly just sct/isold rain showers mainly over inland locations in the west. Highs still struggle back into the lower 40s north to the upper 40s south. .LONG TERM...(Friday night through Thursday) Issued at 406 PM EDT THU OCT 1 2020 Mid to upper level troughing will continue over the Upper Great Lakes through most of the weekend with cooler temperatures and periods of mostly lake-effect rain showers but can`t rule out some snowflakes mixed in Friday night into Saturday. Troughing finally begins to lift away Sunday with a shortwave approaching before brief ridging and zonal flow Beginning early next week, the pattern briefly becomes more zonal flow Monday into Tuesday. Latest guidance continues to show another shortwave and cold front Tuesday and Wednesday which will bring next chance of showers and temperatures dipping back to around or just below normal for this time of year. With that upper-level low still hanging around Friday night and with enough moisture and inversion heights being around 800-900mb, still could expect some lake-effect rain showers to occur with a few snow flakes mixed in. Winds will be subsiding as well which should limit the coverage of any lake-effect precip and should end late Friday or early Saturday. Have continued to have slight PoPs in the for the lake-effect. A shortwave will approach Upper Michigan late Saturday into Sunday, which may end up tracking just south of Upper Michigan and may keep showers out of the cwa. Either way, the upper-level trough will linger into Sunday morning before finally starting to move away from the region. In its wake, developing weak north-northeast flow could be some isolated lake effect rain showers, mixing with some snowflakes/graupel inland late Saturday into Sunday morning before drying out by Sunday afternoon. A brief period of rising heights and waa thanks to ridging over the west-central CONUS, will make the flow more zonal by Monday with drier conditions and southwest waa flow and as a result ahead of the next shortwave, breezy southwest winds is a possibility. 12z GFS is running high compared to the Canadian and ECMWF so we`ll see how this trends over the coming days. With 850mb temps between 5C-7C, this will result in mid to upper 50s for highs. Another shortwave with an associated cold front, looks to move through late Tuesday into Wednesday with southwest flow changing to northwest flow behind the shortwave. Temperatures Tuesday will be around the 60 degree mark but slowly cooling down by Wednesday into Thursday with mostly lower 50s. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 746 PM EDT THU OCT 1 2020 Thru Fri, cold northerly flow across Lake Superior will lead to lake effect -shra/-shsn affecting KIWD/KCMX/KSAW at times. Some of the showers may be heavy enough to drop vis briefly to MVFR. Expect cigs to settle into MVFR tonight, but there will be periods of VFR. Pcpn will change back to just -shra during Fri, and cigs at all terminals will return to prevailing VFR. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 409 PM EDT THU OCT 1 2020 Expect winds to remain elevated from the north into tonight with continued CAA, but slowly diminishing to around 20 knots by tomorrow morning as sfc high pressure moves in from the west. This high pressure persists through the weekend. Models are suggesting a trof to pass over Lake Superior on Tuesday evening, which may bring an increase in winds from the SE to 25 knots ahead of the trof, becoming NW behind the trof to around 25 knots as well. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...JH AVIATION...Rolfson MARINE...JLB
Area Forecast Discussion
National Weather Service Pueblo CO
306 PM MDT Thu Oct 1 2020 .SHORT TERM...(This evening through Friday) Issued at 306 PM MDT Thu Oct 1 2020 Current water vapor imagery and upper air analysis is indicating weak to moderate northwest flow aloft across the region, with a broad upper trough in place across the central CONUS and upper level ridging across the West Coast. Water vapor imagery is also indicating eastern Pacific energy topping the ridge across the Pacific Northwest Coast and translating into the Intermountain West at this time. GOES visible imagery is indicating an active smoke plume from the Mullen wildfire of south central Wyoming, which as of yesterday crossed into north central Colorado. However, we are not currently seeing much smoke across south central and southeast Colorado, with the higher terrain west of the I-25 Corridor clearly visible, though a touch hazy. Temperatures are indicating a taste of fall today, with current readings mainly in the 50s and 60s areawide. Tonight-Friday...Northwest flow aloft progged to increase slightly through the day tomorrow, as energy topping the ridge continues to translate across the Northern Tier and into the Upper Midwest. Models do indicate some increasing high level clouds across the region through the overnight hours, though clouds to be generally thin enough to allow for another night a strong radiational cooling with lows at and below seasonal levels, coldest across the valleys. The main concern continues to be how much smoke and how thick it will be as it moves across eastern Colorado tonight and through the day tomorrow. The HRRR smoke forecast remains very bullish at increasing the vertically integrated smoke column across the Pikes Peak region and southern portions of the I-25 Corridor through the evening, with the greatest concentration of smoke then pushing out across northern portions of the southeast plains through early Friday morning before the elevated smoke mixes to the surface later Friday morning and afternoon across southeast Colorado. With that said, have kept areas of smoke in the forecast across eastern Colorado through the period, though will need to continue to monitor smoke and visibility trends across northern Colorado to see how and if these trends could lead to restrictions to visibility across southern areas. Also depending on how thick the smoke may be tomorrow, highs should warm back up above seasonal levels with expected highs in the 70s and lower 80s across the southeast plains, with mainly 50s and 60s across the higher terrain. .LONG TERM...(Friday night through Thursday) Issued at 306 PM MDT Thu Oct 1 2020 Dry conditions prevail through the extended. Friday night and Saturday...The ridge of high pressure will continue across the western US into the weekend, with a two-part dry cold front forecast to push through the area starting Fri night. The initial cold front will drop south across the eastern plains Fri evening, then a stronger surge of cold air is expected to push in Sat morning. This will drop high temps on Sat into the mid 60s to lower 70s for most areas. Sunday through Tuesday...The high pressure ridge begins to flatten on Sunday as a stronger upper wave crosses the Pacific NW and the northern Rockies Sun eve through Mon. Temps will rebound for Sun, become extremely warm for Mon, then cool a couple of degrees for Tue as the upper flow decreases. High temps will remain in the 70s each day for the high valleys, but will vary a bit for the plains. On Sun expect max temps in the 70s to near 80F. Mon the mercury jumps up into the mid to upper 80s, but thankfully winds are not anticipated to be strong enough to warrant any sort of fire weather highlight. Tue forecast highs for the plains will then be in the mid 70s to lower 80s. Wednesday and Thursday...The weakening ridge begins to gradually slide to the east, with the ridge axis crossing Colorado Wed eve. Expect warm temps to persist, with highs across the plains hovering in the lower to mid 80s. Moore && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 306 PM MDT Thu Oct 1 2020 Generally VFR conditions with light diurnal wind regimes are expected at COS, PUB and ALS over the next 24 hours. For COS, PUB and eastern Colorado, will need to continue to monitor upstream smoke and vis trends, as smoke from south central Wyoming and north central Colorado wildfires could bring an increase in smoke, and potential restrictions to vis, late tonight and through the day on Friday. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...MW LONG TERM...MOORE AVIATION...MW
Area Forecast Discussion
National Weather Service Blacksburg VA
907 PM EDT Thu Oct 1 2020 .SYNOPSIS... A frontal boundary will slide east across the piedmont tonight and offshore early Friday. High pressure works in for the start of the weekend. Another cold front enters the region later Sunday into Sunday night. && .NEAR TERM /THROUGH FRIDAY/... AS of 907 PM EDT Thursday... A cold front will move southeast across the region tonight into Friday morning. High pressure will build in behind the front Friday. Scattered showers continue to form along the frontal boundary with the moisture convergence. For this update, extended the duration and coverage a little of showers along the boundary tonight. Also modified temperatures and low readings for overnight into Friday. As of 650 PM EDT Thursday... Surface frontal boundary will move southeast across the region tonight. Scattered showers will developed with the surface convergence along the front. The best chance will be in the southeastern portion of the forecast area. Made a few adjustments to pops and weather to capture radar trends and blend in the HRRR for this evening into tonight. Modified temperatures tonight utilizing the latest surface obs, their trends and mixed in the NBM. more changes later... As of 200 PM EDT Thursday... High-res models are still favoring shower development mainly east of the Blue Ridge this afternoon as low works north along a cold front, coincident with strengthening shortwave into the central Appalachians. However, moisture is limited in this airmass. Given the strength of the shortwave and strong convergence along the front, will maintain chance pops mainly east of the Blue Ridge, to low likelys east of Lynchburg. Rainfall will be light overall, with a few locations attaining a quarter inch at best. Lack of instability leads to no thunder. Shower chances will be highest in the 7pm to 11pm time slot. Clearing takes place west to east this evening into the morning Friday. Lows tonight will range from the lower 40s west to upper 40s to lower 50s east. High pressure works in Friday with cold air advection and lower dewpoints. Despite sunshine, high temperatures will run from the 50s in the mountains, to the 60s east. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... As of 200 PM EDT Thursday... Expect quiet weather to persist into the first part of the weekend. However, guidance is in good agreement with a progressive upper trof pushing a weak surface low through the Ohio valley and dragging a cold front through the area. This will bring a good chance of showers back to the forecast by late Sunday and into Sunday night, especially west of the Blue Ridge. Temperatures will remain a good bit below normal through the weekend. Highs will generally be in the mid/upper 60s east of the Ridge with lower 60s to the west. Lows Friday night will be chilly with lower 40s east, 30s west and some frost possible as the normally colder locations may dip to around the freezing mark. Lows then slowly moderate through the 40s over the weekend. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 200 PM EDT Thursday... Guidance is in generally good agreement in developing a low amplitude, progressive upper flow regime which eventually trends to a western ridge and an eastern trof. So after any lingering showers early on Monday dissipate, it looks like generally quiet weather through the middle of next week before another cold front brings some blustery conditions and a chance of showers back to the forecast toward Wednesday night. Temperatures look to be close to seasonal norms through the period. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/... As of 730 PM EDT Thursday... A cold front will travel southeast across our region tonight into Friday morning. High pressure will build in for the weekend. Scattered MVFR showers are possible along the frontal boundary especially during the next couple of hours. Behind the front VFR conditions will prevail tonight into Friday. Above average confidence for ceilings, visibility and wind. .Extended Aviation Discussion... Mainly VFR conditions through the period. A frontal boundary arrives late Sunday into Monday which may bring a few showers and sub-VFR to the mountains. Dry weather is expected for Tuesday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...WP NEAR TERM...KK/WP SHORT TERM...MBS LONG TERM...MBS AVIATION...KK/WP
Area Forecast Discussion
National Weather Service Las Vegas NV
240 PM PDT Thu Oct 1 2020 .SYNOPSIS...A strong ridge of high pressure over the western states will lead to near-record highs through Saturday. North breezes can be expected through Friday, especially down the Colorado River Valley. Conditions will remain warm and dry through the weekend and at least the middle of next week. && .SHORT TERM...through Friday. With strong high pressure overhead, temperatures will remain several degrees above normal into early next week. It`s possible that Las Vegas could reach 100 degrees Friday and just a slight chance of Saturday as temperatures are forecast to drop slightly. Gusty north winds down the Colorado River Valley have diminished slightly, but are still expected to remain elevated into this evening. Some north winds are expected again Friday, but overall speeds should be lower. The latest HRRR Smoke Forecast indicates wildfire smoke from the southern Sierra will be directed away from Inyo County and southwest Nevada today through most of Friday to the east-southeast flow in the H7-H5 layer. However, there is some indication that smoke may start to impact the northern portions of the Owens Valley as early as Friday night into Saturday. .LONG TERM...Saturday through Wednesday. High pressure remains in control through the period, leading to a continuation of dry weather with temperatures well above normal for early October. There are some hints of a possible pattern change beyond this time frame, but there is a lot of uncertainty regarding the strength and position of a cold low pressure system in or near the Gulf of Alaska as well as the remnants of eastern Pacific Hurricane Marie. Will continue to monitor. && .FIRE WEATHER...With strong high pressure overhead temperatures will reach near records through Saturday. Temperatures will start a slow cool down into next week, but will still remain several degrees above normal. Conditions are also expected to remain dry with single digit RHs in the afternoon and generally poor to moderate recoveries overnight. Other than some gusty northerly winds down the Colorado River Friday, the remainder of the area is expected to see typical diurnal winds. && .AVIATION...For McCarran...Generally diurnal wind patterns are expected through Friday with afternoon northeasterly winds in the 8- 10 knot range. Clear skies are expected. For the rest of southern Nevada, northwest Arizona and southeast California...Little impacts expected through Friday other than some gusty north winds down the Colorado River Valley. Smoke is expected to stay west of the Owens Valley through Friday evening, but there is some potential of smoke moving into the area by early Saturday morning bringing some reduced visibility. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM...Gorelow LONG TERM...Morgan AVIATION...Gorelow For more forecast information...see us on our webpage: or follow us on Facebook and Twitter