Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/14/18

Area Forecast Discussion
National Weather Service Cleveland OH
1013 PM EST Tue Nov 13 2018 .SYNOPSIS... High pressure will build in from the west over the lower Great Lakes by Wednesday. The high will move northeast to Maine by Thursday. Low pressure will move northeast to the Ohio Valley by Thursday and then shift to the East Coast by Thursday night. High pressure will build up the Appalachian Mountains Saturday with a cold front moving east across the local area Saturday night. && .NEAR TERM /THROUGH WEDNESDAY/... Update...Will continue trend of decreasing snow showers off lake erie across northwest pa although did lower pops to likely/chance from categorical. Minor sky cover adjustments as well but no big changes for overnight update. Original...Satellite imagery and regional radars shows lake enhanced and lake effect clouds and scattered snow showers this afternoon. 850mb temps advecting in over the region are -10C to -12C. These colder temperatures aloft are causing about 50 to 100 J/KG of MUCape and instability. Using area TWDRs and mosaic imagery shows bands of light snow developing over the lake this afternoon and impacting the primary Snowbelt region east of the Cleveland area. We followed the guidance from the HRRR and NAMnest closely with several bands expected to develop and impact far northeastern Ohio into northwestern Pennsylvania. At this time, we will mention the possibility of 1 to 2 inches across NE Ohio and 2 to 4 inches with isolated higher amounts across Crawford and Erie Counties in Pennsylvania. At this time, we will not issue an advisory for the primary snowbelt areas. But if more snow is anticipated this evening, a quick headline may need to be issued. Lake effect cloud cover will hold on for downwind of the lake this evening and overnight with so eroding of the clouds during the day on Wednesday. Coldest temperatures will be closer to western and central Ohio tonight with readings down to near 20 degrees. Tomorrows highs will be mostly depending on the amount of sunshine but mid 30s are expected across much of the area. All lake effect snow showers will be done and fair skies late on Wednesday. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... Little change in the short term forecast. Coastal low will develop and track up the East Coast Thursday, lifting a trough across the forecast area. Nice WAA pattern setting up. Expect some light snow to develop from the south in the morning, gradually changing to rain over entire area by late afternoon. Potential for a brief period of sleet or freezing rain as precip transition with overrunning. Bulk of the precip will have exited the area by daybreak Friday as low tracks into New England. Potential for some lake effect snow showers in the snow belt on Friday. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Below normal conditions continue through the long term forecast. Models continue to differ on the timing of the next cold front. The ECMWF moves the weak front through on Saturday while the GFS holds off until late saturday night into Sunday. With so much doubt in the timing will continue with low chance pops Saturday into Sunday. && .AVIATION /00Z Wednesday THROUGH Sunday/... Expect slowly improving conditions through the night and into Wednesday as high pressure and drier air move in from the west. Will need to hang onto snow showers KERI for a few more hours but do not expect visibility restrictions. Otherwise there biggest threat for patchy MVFR CIGS at KMFD, KYNG and KCAK mainly through the evening. Otherwise expect VFR. OUTLOOK...Non-VFR possible Thursday night and Friday. && .MARINE... Updated...Winds a bit higher on the west end than earlier anticipated so issued a small craft advisory. Winds will be coming down through the early overnight period so will end at 4am. Original...Small craft advisory will continue into tomorrow with NW flow of 15 to 25 knots. Winds diminish from the west tomorrow as the low tracks across Quebec, and high pressure builds over the Lower Lakes. Winds shift to the S to SE tomorrow night as the high moves east of the Lake. Another coastal low develops and deepens to 29.40 inches off the Mid Atlantic Coast by Friday morning, with a trough across the Lower Lakes. A small craft advisory will be needed. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Small Craft Advisory until 10 AM EST Wednesday for LEZ145>149. Small Craft Advisory until 4 AM EST Wednesday for LEZ143-144. && $$ SYNOPSIS...Griffin NEAR TERM...Griffin/TK SHORT TERM...DJB LONG TERM...DJB AVIATION...TK MARINE...DJB/TK
Area Forecast Discussion
National Weather Service Cheyenne WY
157 PM MST Tue Nov 13 2018 .SHORT TERM...(This evening through Wednesday) Issued at 146 PM MST Tue Nov 13 2018 No hazards or highlights in the short term with a nice warming trend continuing today and moreso tomorrow. Temperatures remain just below average today but will warm to near average and slightly above average Wednesday with mostly sunny skies. Latest water vapor imagery and RAP analysis indicates deep northerly flow over WY and NE. Despite this wind direction, warm air advection has taken place since yesterday as the colder Canadian air has shifted farther east. This pattern switch is allowing for surface temperatures to warm into the mid 40s for the WY High Plains and even into the low 50s for the NE Panhandle. Winds aloft will become more westerly overnight and Wednesday as a shortwave ridge builds over the region. The subsident and down-sloping wind component will further aid in the warming trend as low 50s look probable for High Plains of WY with near 60F in the NE Panhandle. These reading are about 3-8F degrees above daily climate normals. The warm trend continues Thursday and slightly into Friday before turning sharply colder late Friday and into the weekend. See more details below on the high chance of snow late Friday and into Saturday across the region. .LONG TERM...(Thursday night through next Monday) Issued at 315 AM MST Tue Nov 13 2018 Long range models in good agreement through next weekend with only minor difference in timing with the next strong cold front late Friday/Saturday. High temperatures on Friday will likely occur earlier in the day with readings in the mid 40s to mid 50s across the region. Models indicate a much colder airmass will begin moving into Converse/Niobrara counties and likely across the northern NE panhandle as early as noon Friday, with temperatures rapidly lowering below freezing later in the afternoon. Forecast looks on track for a potential Winter Weather event beginning late Friday and continuing through Saturday evening across most of the region. All models show a strong cold front digging south along the mountains of Montana early on Friday as a potent upper level disturbance moves southward west of the Continental Divide. Models then show this disturbances digging further west over time and slowing down, providing warm air advection aloft. In addition, moderate frontogenesis and broad upslope flow will be present along the mountains and across the eastern plains. Models in very good agreement with the timing, showing the onset of snowfall beginning Friday evening well north of I-80, and by midnight Friday night/Saturday morning along the I-80 corridor. Widespread light to moderate snow is possible through Saturday morning, with snow generally becoming lighter through the day Saturday. A bit too early to mention snow accumulations, but historically these events tend to produce 2 to 5 inches of snow outside of the mountains. The only exception is when the front and associated upper level trough become nearly stationary, which leads to more snowfall. Thankfully, surface winds do not appear to be too high late this week, which will greatly limit drifting/blowing snow impacts. Continued to increase POP up to 75 percent across much of the region through Saturday with much colder temperatures during the day. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1018 AM MST Tue Nov 13 2018 VFR conditions expected across all terminal sites through the period. Afternoon will have periods of gusty winds across the majority of terminals before lessening during the evening and overnight. Some high clouds possible through the forecast timeframe. && .FIRE WEATHER... Issued at 146 PM MST Tue Nov 13 2018 Fire weather concerns remain minimal through the next several days as fuel moisture is elevated and energy release components remain below normal. Humidity values will drop into the 20 and 30 percentiles while wind increases upwards of 20 to 25 mph at times during the afternoons with the warm spell through Friday. Much colder temperatures expected late Friday and over the weekend as another round of widespread snow will occur across most fire weather zones. Stay tuned for details on amounts towards late week. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...JSA LONG TERM...TJT AVIATION...WM FIRE WEATHER...JSA
Area Forecast Discussion
National Weather Service Lincoln IL
808 PM CST Tue Nov 13 2018 .UPDATE... Issued at 807 PM CST Tue Nov 13 2018 Latest surface map shows high pressure ridge from southwest Wisconsin into Texas. Cirrus continues to stream across the southeast third of the forecast area, which the RAP suggests will continue through midnight before shifting southeast. With the high becoming centered over the CWA by morning, the clear skies will allow most areas to dip into the mid teens by morning, though upper teens are more likely south of I-70. Little change was needed to the gridded forecasts, aside from updating the sky trends. The zone forecasts were updated to correct a formatting error in the afternoon issuance. && .SHORT TERM...(This evening through Wednesday) ISSUED AT 303 PM CST Tue Nov 13 2018 Mostly clear skies expected through Wednesday as central IL sits roughly in a col region between a deepening upper low moving from the southern Plains into the lower Mississippi region and upper troughing heading out of the Great Lakes into the north Atlantic. Winds will be light and variable with weak surface pressure gradients over the area, although a tendency toward a northeast direction will develop during the day as surface low pressure starts to lift northward into the TN region. The air mass remains far colder than normal, and resulting lows should be in the teens tonight, and mid to upper 30s Wednesday. .LONG TERM...(Wednesday night through Tuesday) ISSUED AT 303 PM CST Tue Nov 13 2018 The upper low developing in the southern Plains today looks to follow a track just south of the Ohio River Thursday, spreading precipitation into southeast Illinois starting Wednesday evening south of I-70, continuing until Thursday evening east of I-57. A chance for precipitation looks to spread about as far northwestward as Jacksonville to Bloomington during the daytime Thursday. A fairly persistent band associated with the deformation zone wrapping around the north of this upper low could result in heavy accumulations of snowfall, 4-7 inches, near and south of the I-70 corridor, and a winter storm watch has been issued. Although a wedge of warm air aloft looks to push northward ahead of the low, current models keep any above freezing temperatures aloft east of Illinois, therefore precipitation type looks to remain completely snow until a loss of ice aloft potentially switches precipitation to a brief period of freezing drizzle Thursday evening. Dry zonal flow aloft should keep dry conditions over central IL Friday, then a cold front looks to push southeastward across central IL Saturday, resulting in a chance for light rain and snow. Ahead of the front southwesterly winds should bring highs up to the 40s Friday, still below normal, followed by highs dropping back into the 30s to low 40s for Saturday through Monday. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 506 PM CST Tue Nov 13 2018 VFR conditions are expected to prevail, with mainly high clouds. Only real area of concern is just south of KCMI, where some patches of stratocumulus around 2500 feet currently exist. Hard to tell with the high clouds moving overhead, but GOES-16 satellite imagery suggests this is not really making any northward progress at the current time. Will keep them VFR in the new TAF set as well. Northwest winds will gradually turn toward the north overnight and east-northeast early Wednesday. && .ILX WATCHES/WARNINGS/ADVISORIES... Winter Storm Watch from Wednesday evening through Thursday afternoon for ILZ066>068-071>073. && $$ UPDATE...Geelhart SHORT TERM...37 LONG TERM...37 AVIATION...Geelhart
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
946 PM CST Tue Nov 13 2018 ...WINTER WEATHER AND FREEZING TEMPERATURES EXPECTED OVERNIGHT AND WEDNESDAY... .UPDATE... Updated for evening discussion. && .DISCUSSION... Water vapor imagery/RAP analysis showed the closed low spinning over northeast Texas. This cold low has already pushed the 850mb zero degree isotherm over our western zones Catahoula parish to LeFlore county. Local radar are rather quiet. In fact, have lowered pops in our southeast until after midnight when light rain is still expected to redevelop. As the closed low draws closer light precipitation is expected to develop including a wintry mix as temperatures continue to fall. Latest surface observations still have the freezing line north of Bolivar and Sunflower counties. Morning lows still look on track with with our northwest dropping below freezing well before sunrise. Wl continue the Freeze Warning and Winter Weather Advisory for our northwest. /22/ Prior discussion below: Tonight & Wednesday: Expect an active pattern of continued cold conditions & winter weather potential through the period. Tonight a deep upper cold core low will be diving down over the ArkLaTex while split level flow & synoptic trough will be swinging through the Great Lakes. At the surface, a strong surface ridge will be building east- northeast across the mid-Mississippi Valley & into the Great Lakes into tomorrow. Due to low-level cold air advection & strong surface ridging (i.e. ~1025-1030mb MSLP across the region), expect temperatures to slowly fall overnight into the evening. Guidance is in good consensus that temperatures will fall to near or below freezing in the ArkLaMiss Delta & near that along & northwest of the Natchez Trace corridor. Went near a blend with raw consensus guidance. Overall, previous thinking in the HWO & graphics look good overall & no changes were needed. Kept the current freeze warning area going after midnight tonight & through around mid- morning Wednesday. Overall, only hindrance to lows could be any winds & widespread clouds but favored leaning towards raw guidance in this situation. As this cold core low swings east-northeast into Wednesday morning & through the day, expect increasing low-mid level moisture to advect into the area. In addition, expect increasingly cool profiles but there could be a low-level warm nose to deal with into the afternoon, especially further east & southeast of the Natchez Trace corridor. However in the ArkLaMiss Delta, there is less of that & with continued cooling aloft & low-level wet bulb temperatures near or less than freezing, a light wintry mix changeover is possible in the morning after 3-4AM, especially in the ArkLaMiss Delta. Further southeast towards the Natchez Trace corridor, some areas could see a mix of light freezing drizzle or light snow flurries but the best potential will remain in the ArkLaMiss Delta from Morehouse Parish in Louisiana, Ashley & Chicot Counties in Arkansas & along & northwest of a line extending east-northeast towards Carroll & Grenada Counties. This lines up well with neighbors & WPC on freezing rain probabilities in the Delta. Right now this changeover could happen as early as 3-4AM with a majority after daybreak. There is some potential this could extend further east & south, but some mid-level dry punch could be a limiting factor. However, the CAM guidance, including the ARW & NMM & op NAM are more bullish on QPF totals, but with the op Euro backing off slightly, didn`t want to go as far southeast as some of the more bullish guidance. HRRR seems to be somewhat of a blend of the two with some developing in the Delta with a minimum in between & more rain in east & southeast Mississippi. In the I-20 corridor to Natchez Trace corridor, some mix may be possible but moisture limitations keep out the mention of more significant freezing rain. However, did leave at least mention of snow flurries in. Regardless, as we struggle to warm into the mid- upper 30s in the day, some of this will transition back to rain as we warm up. However, this may be short lived as somewhat colder thermal profiles continue to filter in into the evening. One caveat is the Euro is slightly faster, which would keep most of the developing precip slightly further north. Main takeaway is even though accumulation will be light, in some areas, especially the winter weather advisory area, a potential of a wintry mix with up to a light glaze of ice & snow accumulations up to one half inch, especially on elevated surfaces. However, this is subject to change if the system moves in slower & thermal profiles are colder & more saturated. Regardless, make preparations now to account for some wintry mix potential Wednesday. /DC/ Wednesday Night through early next week: Precipitation should be coming to an end as we get into Wednesday night and the closed low begins to eject northward out of the MidSouth while high pressure at the surface begins to filter into the ArkLaMiss from the southwest. However, some light flurries will be possible mainly before midnight in the northeastern portions of our region as precip comes to an end. Temperatures will fall into the 20s areawide by Thursday morning as cold air continues to advect into the region. A freeze watch has been issued for the entire region and the freeze threat has been advertised in the HWO. Drier air will continue to filter into the region on Thursday resulting in decreasing cloud cover. The decrease in cloud cover and lighter winds due to the surface high settling over the northern Gulf Coast will help to aid the diurnal cooling effect for Friday morning. Expect temps to fall into the 20s once again. Temperatures will begin to warm as we get into the weekend and the surface high moves east of the area. However, temps are still expected to remain at least a few degrees below normal through the period. Dry conditions will persist through the weekend. /JPM3/ && .AVIATION... 00Z TAF discussion: MVFR flight categories were observed north of I-20 at 2330Z while IFR flight categories continued along and south of I-20. IFR conds are expected to prevail areawide by 09Z and continue through Wednesday afternoon. An area of -RA and -DZ wl continue over the se this evng then develop across the remainder of the area Wednesday morning. Some flurries and light freezing rain wl be possible across the nw from daybreak through noon before -RA becomes predominant again. Wednesday evng additional flurries and light freezing rain wl be possible across the ne, primarily GTR, before the PCPN ends. /22/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 34 38 27 48 / 17 24 11 2 Meridian 37 41 28 48 / 39 49 22 4 Vicksburg 32 37 26 50 / 12 16 8 1 Hattiesburg 38 42 28 51 / 46 39 10 2 Natchez 33 38 27 51 / 10 11 6 1 Greenville 30 36 28 48 / 9 34 16 2 Greenwood 32 36 28 45 / 11 35 23 6 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...Freeze Watch from late Wednesday night through Thursday morning for MSZ018-019-025>066-072>074. Winter Weather Advisory from 3 AM Wednesday to midnight CST Wednesday night for MSZ018-019-025>027-034. Freeze Warning from 2 AM to 9 AM CST Wednesday for MSZ018-019- 025>028-034>036-040>042-047. LA...Freeze Watch from late Wednesday night through Thursday morning for LAZ007>009-015-016-023>026. Winter Weather Advisory from 3 AM Wednesday to midnight CST Wednesday night for LAZ007. Freeze Warning from 2 AM to 9 AM CST Wednesday for LAZ007>009- 015-016-023>025. AR...Freeze Watch from late Wednesday night through Thursday morning for ARZ074-075. Winter Weather Advisory from 3 AM Wednesday to midnight CST Wednesday night for ARZ074-075. Freeze Warning from 2 AM to 9 AM CST Wednesday for ARZ074-075. && $$ JPM3/22/DC
Area Forecast Discussion
National Weather Service Nashville TN
753 PM CST Tue Nov 13 2018 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Upper low approaching the Arklatex region this evening. Rainshowers covering much of the deep south, including Ga and the southern two thirds of AL. Moisture is expected to lift northward overnight and may reach into our far southeastern areas by 12z. Hrrr concurs with this solution. BY 12z freezing heights are sufficient for snowfall but 850 mb temps are rather warm. Still though, with 850 mb wet bulbs close to 0C, will elect to continue the slight chance of a rain and snow mix toward sunrise in the far south. Temperatures should be near or just above freezing across that far southern area around 12z. Remainder of fcst looks to be in good shape. Weak Caa to continue overnight so will see temps drop down a degree or two more. Update will be sent in the next hour. && .AVIATION... 00Z TAF DISCUSSION. Cigs will continue to improve a bit overnight, with MVFR returning for all terminals, however, IFR will make its return early tomorrow afternoon as rain moves back into Middle TN. Look for IFR to remain for awhile once it returns. Winds will continue to be occasionally breezy out of the north, then shift to the northeast tomorrow ahead of our next weather system. && .OHX WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 6 PM Wednesday to noon CST Thursday for Houston-Humphreys-Montgomery-Stewart. && $$ DISCUSSION......21 AVIATION........Unger
Area Forecast Discussion
National Weather Service Portland OR
755 PM PST Tue Nov 13 2018 .SYNOPSIS...Offshore flow through the Gorge will continue to weaken tonight and Wednesday. A weak frontal system passes over the area tonight and Wednesday, but precipitation will favor the north half. Another weak impulse drops southeast from British Columbia late Thursday night and Friday morning. Strong high pressure returns over the weekend and is expected to hold into early next week. This will also result in another round of east wind through the Columbia Gorge. && .SHORT TERM...Tonight through Friday...No changes. Previous discussion follows. East wind continues through the Gorge this afternoon, but not quite as strong as early this morning. At 21Z the KTTD-KDLS gradient was around -6.0 mb. This was enough to produce 55 mph gusts at Crown Point and 40-45 mph at Corbett. 18Z NAM suggests the KTTD-KDLS gradient will drop to around -3.5 mb by 12Z Wed, which is several hours slower than the 12Z version. This trend is more plausible considering the stratus field piled up in the Central Gorge and Upper Hood River valley, which is indicative of cross-Cascade flow. KTTD profiler indicates a rapid weakening of the primary east wind core late this afternoon. Another added forecast twist is the potential for California wildfire smoke to be over the area. The 12Z HRRR 6000 ft AGL smoke product indicates some degree of drift smoke to be over the region tonight. The strengthening SW 850 mb flow will push it east late tonight and Wed, but higher concentrations are possible over the south part of the area, such as Lane County. Less cloud cover tonight and minimal to no wind could lead to short-term periods of moderate to unhealthy for sensitive groups air quality categories. Although not in the forecast or grids, would not be surprised to see isolated flurries fall out of the stratus field in the Central Gorge and Upper Hood River Valley. Water vapor satellite imagery shows a weakening low level front just inside 130W at 21Z that will likely stall just off the Washington coast late this evening. The 12Z NAM was a little slower with it, which makes sense as it enounters strong surface high pressure. However, the 850 mb SW-W flow strengthens to 20-30 kt tonight and Wed. This should be enough to help scour the cold air in the Central Gorge and Upper Hood River Valley. Rain still appears very unlikely across our southern zones, including places like Corvallis and Eugene. With the bulk of the upper level support moving eastward across southern Canada Wed, the front should stall out across our northern zones and fall apart Wednesday night into early Thursday with rain chances decreasing fairly quickly during that time. H5 high pressure will be centered along 130-135W Thu night. This is far enough offshore to allow short-waves within northwest flow aloft to be in close proximity to the area. One such feature slides across NE Washington 12Z Fri. Models suggest there may be enough cyclonic curvature to the flow for a threat of precip in SW Washington and the North Oregon Cascades from Mt. Hood northward. Southern interior valleys will likely see areas of fog Thu night through Fri morning. The upper ridge amplifies Friday afternoon, which will result in light north low-level flow. Friday could be the start of air quality issues due to weak transport wind and minimal surface flow. Fortunately, the 850-700 mb mean layer flow Fri will be NW-N. This would not be favorable for transport of California smoke into the forecast area. Weishaar .LONG TERM...Friday Night through Tuesday...No changes. Previous discussion follows. Deterministic models are in agreement that a sharp upper level ridge will remain over the forecast area from Friday night into Saturday resulting in dry conditions. Both the GFS and ECMWF show precipitation arriving along the coast by Monday night as a weak front pushes on shore. This precipitation pattern looks to stay in the extended forecast through Tuesday and into Wednesday. Weak winds in the Willamette valley allow for the persistence of early morning fog and temperatures trend slightly downward and stay within seasonal norms. -BPhillips && .AVIATION...VFR conditions to begin with this evening, but a slow moving cold front moving se across nw Oregon over the next 24 hours will bring lowering cigs and chances for light rain. Cigs along the north coast will be the first to lower, expected to drop into MVFR category by 09Z. Further to the south and east cigs will be slower to come down, as late as 18Z to 00Z in the south willamette Valley. The likelihood of cigs dropping into MVFR category also decreases to the south and east, although all locations in nw Oregon stand at least a chance of doing so. PDX AND APPROACHES...VFR conds to continue through at least 12Z Wed morning, and perhaps longer. After 12Z there is an increasing chance to see MVFR cigs settle in. Expect low end VFR to MVFR cigs to then continue past 00Z Wed afternoon. && .MARINE...No changes. Previous discussion follows. An approaching cold front has slowed from earlier forecasts. SCA level winds of 21+ kts are sitting just outside the northwest corner of our waters per an earlier satellite derived wind pass. Still expect gusts around 25 kt for tonight across the northern waters, but have delayed the onset of the inner waters until about mid-evening. Have also delayed the frontal passage by a few hours. Now expect the front will move onshore around mid-day Wednesday with winds becoming light westerly behind the front. High pres will build over the waters for Thu and Fri, bringing a period of northerly winds. Then more offshore flow is looking increasingly likely next weekend but not especially strong at this point. Seas will remain 5 ft then build into the 7 to 9 ft range tonight with the front. A trailing dynamic swell train will then briefly bring westerly seas near 10 ft Late wednesday night and early Thursday. Seas than drop to between 5 and 8 feet for several days thereafter. /JBonk && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory for winds until 10 AM PST Wednesday for Waters from Cape Shoalwater WA to Cascade Head OR from 10 to 60 NM. Small Craft Advisory for winds until noon PST Wednesday for Coastal waters from Cape Shoalwater WA to Cascade Head OR out 10 NM. && $$ Interact with us via social media: This discussion is for Northwest Oregon and Southwest Washington from the Cascade crest to 60 nautical miles offshore. This area is commonly referred to as the forecast area.
Area Forecast Discussion
National Weather Service Reno NV
213 PM PST Tue Nov 13 2018 .SYNOPSIS... High pressure will lead to dry and stagnant conditions through the week. Localized degradation of air quality is possible under valley inversions. A pattern change next week may open the door for a couple of weak storm systems but heavy precipitation is unlikely. && .DISCUSSION... Not much change in the overall ideas for the forecast the next 7 days. However, there were some minor adjustments in the next 36 hours with regards to smoke and haze from the Camp Fire, and the potential storm next week. The ridge remains with a weak wave passing into the Pacific Northwest the next 24 hours. It will keep abundant high clouds across the region. In addition, it is changing the flow aloft to a light west. At the surface it normally wouldn`t mean much as general light slow winds will continue. However, upslope winds on the west slope of the Sierra will bring some smoke and haze east of the crest later tonight into tomorrow. The HRRR smoke shows it getting to almost I-80 by tomorrow afternoon and have added it to the forecast as it fits the conceptual models. We aren`t sure just how dense the smoke will be and associated air quality impacts, but expect some reduced visibility in haze at a minimum. This pattern will continue through Saturday, and if the Camp Fire continues to produce a bunch of smoke, air quality will deteriorate. This weekend, the backdoor front that was depicted on the 00Z runs is well east in the 12Z runs and ensembles. So there may be little change, and a persistent pattern through Monday. For the middle of next week, there is higher confidence in a system moving in with some rain and snow. The ensembles all show troughing along the West Coast by Wednesday. The details of how much precip, and the snow levels will still need to be worked out. What I can say is it doesn`t look any bigger than a routine winter storm at best. The best news is that almost all ensemble runs do NOT have a significant downslope wind event before the precip moves in. Looking at the ensembles, the chances of a significant downslope event are less than 20% as of this writing. X && .AVIATION... VFR with high clouds and light winds the next 24 hours. The biggest impacts may be smoke from the Camp Fire after 12Z Wednesday. Mtn obscuration may occur with the smoke and haze, with the best chances of reduced visibility through Wednesday west of a KSVE to Portola line. Smoke and visibility impacts may increase later in the week if the Camp Fire continues to burn actively. X && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ For more information from the National Weather Service visit...
Area Forecast Discussion
National Weather Service Sacramento CA
319 PM PST Tue Nov 13 2018 .SYNOPSIS... Dry weather with cool nights and above average high temperatures continues through the week. Diminishing winds ease critical fire weather conditions, but widespread smoke from the Camp Fire will continue to impact the area. && .DISCUSSION... Pacific short wave trof encountering the highly amplified ridge axis over Wrn NOAM won`t bring any rain, but it is spreading a plethora of high cloudiness over our CWA, masking the smoke layer from the Camp WF in Butte Co. HRRR smoke loop suggests the smoke layer will shift Ewd across the coastal range later today and overnite. Otherwise, light/lighter winds and limited mixing height (generally 1 to 1.5 kft) will tend to keep persistent smoke over a large portion of the region for the next couple of days. Still looks as if this initial batch of high cloudiness will exit our region Wed morning while additional high cloudiness will spill over the persistent ridge Wed afternoon and Thu. This timing suggests radiational cooling around sunrise could drop temps into the low to mid 30s from MYV-MOD where some light frost could form in outlying areas as humidities are forecast to recover now that the Nly winds have subsided. Without any major changes in the weather pattern through the end of the week there is little daily change expected in the weather over our region. Smoke is expected to keep temperatures locally cooler the next couple of days, otherwise they will continue to run near or above normal while mins run a few to several degrees below normal. JHM && .EXTENDED DISCUSSION (Saturday THROUGH Tuesday) Ridging re-amplifies along the W coast this weekend as a GOA/Wrn Canadian trof slides across the Canadian and Nrn Rockies. Most of the max temps in the Valley will be in the 60s, with some low 70s in the Nrn Sac Vly and surrounding foothills. These temps are about 10 degrees above normal N end of the Vly and many mtn locations to about 5 degrees above south end of the Vly. The wx pattern is forecast to change by Mon as low pressure forms off the SOCAL coast with the lower heights allowing for a deeper, longer wave trof to develop over the Ern Pac. There are now rumors of rain over Norcal for the middle of next week, but model differences continue to cause low confidence in timing and amounts. 13/00z ECMWF suggests as early as Tue nite into Wed and Thu, while the GFS suggests some rain spreading into our area Wed and continuing into Thu. However, the 13/12z ECMWF moves this system through our region on Thu. Although the common theme for rain is "mid week," the timing differences are problematic. The GFS 5-wave chart forecasts a displacement of the mean 5H ridge into the mid section of NOAM with a mean trof over the Ern Pac near 130W which would support a pattern change. Have introduced some PoPs Tue nite, the last grid block. JHM && .AVIATION... Widespread MVFR likely the next 24 hours across the entire Sacramento Valley with local IFR conditions due to smoke from the Butte County wildfire. Northerly winds under 10 knots. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$