Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/03/20

Area Forecast Discussion
National Weather Service Columbia SC
1033 PM EDT Fri Oct 2 2020 .SYNOPSIS... A pressure ridge centered to the north of the area will extend into the area over the weekend. The air mass will be cool and dry through Saturday with moisture near the coast along stalled frontal boundary but may spread into eastern South Carolina Sunday with a few light showers. A dry cold front will move through the area Sunday night. Temperatures will moderate next week and mainly dry conditions expected. && .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... Skies have cleared with sunset and temperatures are quickly falling as radiational cooling conditions are optimal. Overnight expect skies to remain clear and with light winds temperatures will fall into the mid to upper 40s for most locations with some outlying and typically cooler areas in the lower 40s. && .SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Saturday and Saturday night...Upper level trough axis west of the area producing southwest flow aloft. At the surface, high pressure to move from the Ohio Valley to the Mid Atlantic region. Northeast surface flow will hold a dry and cool airmass in place. PWATs around one-half inch. Under mainly clear skies, afternoon highs will warm to the low and mid 70s with overnight lows in the mid 40s to mid 50s. Sunday and Sunday night...The 12z NAM has come into agreement with the GFS and ECMWF with mainly dry conditions. Low pressure moving along a coastal front will hold most of the rain off the coast. Fast moving clipper type system moves across the Mid Atlantic region Sunday night as upper trough amplifies. Moisture limited and lift to the north of the area so cold front should move through dry. Little change in air mass with high temperatures in the low to mid 70s. Low temperatures will be upper 40s and lower 50s as front will be weak. The HRRR integrated smoke model indicated smoke aloft spreading over the area on Sunday as the upper level trough deepens to our west, producing a southwest flow. This smoke can be seen along the coastal Carolinas and southern GA this afternoon. && .LONG TERM /MONDAY THROUGH FRIDAY/... High pressure dominates early in the week. Models indicate another moisture starved cold front moving through the region Wednesday night with Canadian high pressure building in Thursday and Friday. Tropical development in the Gulf of Mexico possible during the period. Latest trends suggest dry conditions will dominate across the Carolinas and east central GA as coastal front moves further offshore. Will continue with dry forecast with strong support from latest GFS and ECMWF. Temperatures near or slightly below normal early in the week with some clouds associated with coastal front and then warming trend closer to normal Wednesday and Thursday, then cooling down again Friday. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Dry air mass over the region, with light winds. Despite limited low level moisture, cool air temps over warm waters tonight may provide some localized shallow lake/river valley fog. EXTENDED AVIATION OUTLOOK...No significant impacts to aviation expected through Saturday. Slight possibility of light rain and some CIG restrictions Sunday mainly at KOGB, but confidence low at this time. Models suggest that some smoke from western U.S. wildfires may spread over the area on Sunday, and some minor visibility restrictions are possible. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
National Weather Service Eureka CA
327 PM PDT Fri Oct 2 2020 .SYNOPSIS...Dry and unseasonably warm conditions are expected to continue this weekend across the interior areas as strong high pressure aloft persists. Marine clouds and fog are expected to linger along the immediate coast for the next few days, briefly clearing each afternoon then pushing back onshore each night. Inland temperatures are expected to see a gradual cool down though the weekend. && .DISCUSSION...Little change to the forecast package this afternoon as high pressure aloft maintains a stable and consistent weather pattern. More robust west and northwesterly flow this afternoon should help with smoke concerns...especially across the Humboldt County coastal areas. Eventually by Saturday much of the smoke will only be focused around the large fires while settling, focused mainly over Trinity County per HRRR smoke modeling. For today another warm afternoon will be observed over the interior areas where max temps will once again be well above normal for early October. Some relief is finally on the horizon as the ridge weakens and heights and 850 temps finally fall a bit over the weekend for some modest cooling. Forecast attention and confidence now turning toward a major pattern change possible developing toward next weekend. As the persistent ridge finally breaks down and moves east, forecast models continue to hint at a weather system pulling in tropical moisture from Hurricane Marie. At this time it is too early to get overly excited about potential rainfall but models are in agreement on brining in some rain, cooler temperatures and even high elevation snow to northern CA next weekend. && .AVIATION...Fog and stratus plagued the immediate North Coastal Shore with IFR/LIFR conditions persisting through afternoon. Much of the SKY was OVC001/OVC002 at CEC and ACV, and VIS often reported less than 1/4SM. Around noonday, Visual Satellite Pictures confirmed that skies were mostly clear beyond the immediate coast, but layers of smoke continued to abound due to inland wildfires. For the remainder of the afternoon, some improvement expected at the coastal airports. However, improved CIG/VIS should be shortlived before deterioration occurs again this evening. Inland areas...particularly in Mendocino, MVFR CIGS were reported due to smoke. Smoke also filtered down to surface levels. UKI reported IFR VIS into afternoon. Thinning smoke is expected overnight. LLWS is again possible at UKI in the evening/overnight as north winds above ground level (AGL) will increase. These winds will be in the vicinity of UKI although the stronger winds aloft have shifted southward, but approaching the airport from the south still poses a LLWS flight hazard. /TA && .MARINE...Moderate northerly winds, mainly focused in the southern outer waters, will continue to generate steep seas from 6 to 8 feet at 8 seconds through the weekend. These conditions will expand into the northern outer waters and southern inner waters on Saturday. Small craft advisory is now in place for the outer waters and southern inner waters through Sunday. Conditions will gradually improve Monday as the moderate northerlies pull away westward. A longer-period westerly swell will be reinforced by on Saturday around 6 feet at 15 seconds then slowly subsiding through Monday. && .FIRE WEATHER...A Red Flag Warning remains in effect for portions of Southern Mendocino and Western Lake counties due to gusty north and northwesterlies through this evening. This band of gusty winds will coincide with an already very dry airmass over the entire region. The strongest winds will occur at elevations above 1500 feet and be most pronounced along the upper slopes and ridges. Winds have weekend during the day today but relative humidity in that area has remained very dry, and another pulse of northwest winds is likely later this afternoon before wind significantly weaken overnight. Focus beginning to turn toward next weekend as primary extended models coming into agreement on the potential of a rain producing front crossing areas north of the Bay Area. Given that it is still 7 days out it is hard to get excited about rain potential...especially this time of year and the fact that it is on the heels of a major blocking ridge. Nonetheless substantial rain amounts are being depicted and even if those were reduced by 50% it would still bring wetting rains to the large fires north of HWY well as significantly reducing the widespread smoke. && .EKA WATCHES/WARNINGS/ADVISORIES... CA...Red Flag Warning until 8 PM PDT this evening for CAZ264-276-277. NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory from 1 PM Saturday to 7 PM PDT Sunday for PZZ455. Small Craft Advisory from 7 AM Saturday to 1 AM PDT Monday for PZZ470. Small Craft Advisory until 1 AM PDT Monday for PZZ475. && $$ Visit us at Follow us on Facebook and Twitter at: For forecast zone information see the forecast zone map online:
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
852 PM CDT Fri Oct 2 2020 .UPDATE... 852 PM CDT The going forecast through Saturday morning is in good shape. As was the case on the Day Shift, did continue to consider a Frost Advisory for northwest Indiana where temperatures are in the low 40s as of just before 900 PM, which for the 2nd of October diurnally would usually support at least mid 30s for lows. While patchy frost is probable and areas of frost could occur, satellite supports increasing clouds from the west likely to result in flat-lining temperatures. Both the RAP and HRRR have been consistent with that occurring in northwest Indiana. Will continue to mention frost in that part of the forecast area but confidence on more of a widespread frost remains below the threshold of an Advisory. Elsewhere, patchy frost is possible north of I-88 in northern Illinois given dew points in the mid 30s and some upstream small holes in the clouds. MTF && .SHORT TERM... 306 PM CDT Through Saturday night... Dry conditions are expected through Saturday afternoon with surface high pressure and a dry low-level airmass in place. Regarding overnight temperatures and the potential for frost: with a completely clear sky, the floor on lows tonight is in the lower 30s given the nicely dried-out surface airmass and slackening winds. That said, the presence of thickening stratus upstream across Minnesota, as well as plentiful mid- and high- level cloud cover associated with an approaching system`s jet streak cast a good deal of doubt that we`ll manage these types of temperatures tonight. As a result, while we did give some thought to a Frost Advisory for some of our typical cold spots, the signal for sufficient radiational cooling potential through the night seems too low to warrant any headline issuances at this point. We`ll continue to keep an eye on upstream cloud trends this afternoon and evening. Another shortwave trough currently located over North Dakota will traverse the ever-persisting upper longwave trough situated over the region before encroaching our CWA late Saturday afternoon. Sufficient DPVA, some frontogenetic forcing, and modest height falls will allow for an expansive precipitation shield to develop across the area Saturday evening, but QPF should be limited to a few tenths at most before the shortwave exits on Sunday. Temperatures should fall at a pretty good clip late Saturday night into Sunday morning with the passage of a developing cold front associated with this system, although likely not fast enough to beat the intruding dry air and cessation of more appreciable precipitation chances. Ogorek/Carlaw && .LONG TERM... 233 PM CDT Sunday through Friday... Some lingering rain, associated with Saturday nights weather disturbance, will continue to be possible early Sunday morning, but most areas should dry out by midday. The only exception to this being over parts of northwestern IN near the lake. With a reinforced shot of cool air over the lake, there will be some potential for lake effect showers in this area, which could persist into the afternoon before ending late. Otherwise, Sunday is looking to be another chilly day across the area with highs expected to remain in the mid to upper 50s. Attention then turns to the next potential of frost Sunday night into early Monday morning. Light winds are expected across the area during this time as surface high pressure shifts over the area. This in combination with, what at this time appears to be, mainly clear skies could support good radiational cooling into the low to mid 30s late Sunday night, especially for areas inland from the lake and outside the more urban areas. The surface high will shift to our southeast on Monday, with winds turning southerly in its wake for Monday into Tuesday. Moderating temperatures in this warm air advection pattern will push highs back into the lower 60s for Monday, and potentially up around 70 for Tuesday. A weather disturbance passing mainly to our north on Tuesday may drop a weak cold front over the area during the day, but this looks to do little to the temperatures as the flow quickly shift back out of the southwest Tuesday night into Wednesday ahead of a fast moving clipper system dropping southeastward over Ontario. This system will result in a mild and breezy day Wednesday, with a stronger cold front likely to shift southward over the area during the afternoon. It continues to look dry across the area with this frontal passage, so we continue to advertise a dry forecast. We only look to get a glancing blow at some cooler air in the wake of this front, so we can expect temperatures to be in the lower to mid 60s for Thursday. Thereafter, we look to get back into a mild weather pattern, supportive of highs around 70 for next Friday. KJB && .AVIATION... For the 00Z TAFs... For the Chicago area airports through Saturday: - East-northeast wind speeds greater than 6 kt ending shortly after 00Z, then becoming southerly on Saturday morning - A few showers in the area later Saturday afternoon with an increase in coverage after dark and likely trending to MVFR After a late afternoon lake breeze, the wind speeds of 7-9 kt will ease quickly by 00Z-0030Z. High pressure over the area tonight will depart eastward Saturday morning allowing for winds to turn southerly with speeds likely to remain below 10 kt most if not all of Saturday. While a lake breeze may develop, confidence is high in this remaining east of ORD and MDW. The wind will turn more northwest to north after dark Saturday and north- northeast is possible but speeds look to be less than 7 kt. VFR clouds will prevail through much of Saturday with temporary breaks late tonight/early Saturday. Spotty showers on the regional scale should be present Saturday afternoon with an uptick toward sundown and after. Conditions should remain VFR after the showers begin for a short period but then trend to MVFR with some potential for IFR Sunday morning. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...Small Craft Advisory...IN nearshore waters until 10 PM Friday. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Reno NV
1244 PM PDT Fri Oct 2 2020 .SYNOPSIS... High pressure will remain over the region through the first week of October, bringing warm afternoons, dry conditions, light winds, and chilly mornings. General hazy skies will last across the region through Sunday. && .DISCUSSION... A strong ridge of high pressure remains over the region with high temperatures running 10-15 degrees above normal, but looking to remain just shy of records. The very dry air mass will allow for excellent radiational cooling with overnight lows continuing to drop into the 40s for many valley locations, with 30s in the Sierra. Based on latest high resolution HRRR smoke model along with satellite data, it appears most of the smoke impacts will remain aloft near and just east of the Sierra. This makes sense given the overall light northeast flow in the low levels with a light westerly wind around ridgetop level. Immediately downwind of ongoing wildfires, smoke is likely to continue to bring air quality concerns. We could see the return of lower level smoke spreading farther into the eastern Sierra and western Nevada on Sunday as low level flow returns more to the southwest. The ridge remains fairly stagnant through the first week of October, though does somewhat weaken the early part of next week in response to an undercutting weak closed-low. Impacts from this are rather minimal -- just a few degrees of cooling, but still well above normal. We continue to see signals in longer range ensembles for potential wet and cooler weather starting around the weekend of Oct 10-11. Approximately 3 out of 4 ensemble members from the EPS/GEFS/CMC are showing signals of precipitation, with cooling temperatures. The exact qpf numbers, however, vary greatly. This is likely due to what is currently Hurricane Marie, how this system may evolve, and whether remnant moisture will be entrained into upstream troughs. Marie`s moisture moving directly into the region is an outlying solution, with a 10% or less chance of occurring, but if it did, much higher liquid totals are possible. There is still a 25% chance that the moisture will remain north, with light rain possible for far northern CA/NV and drier/breezy conditions elsewhere. So, while we can say it looks like the dominant ridge will weaken or break down, with a general downward trend in temps, the exact impacts are still TBD. -Dawn && .AVIATION... High pressure will keep light winds and cloud-free skies across the Sierra and western Nevada through the weekend. Primary concern continues to be the smoke and haze, which may impact ceilings and visibilities for terminals through the weekend. Smoke is slowly returning to the Tahoe Basin and portions of the eastern Sierra today through Saturday. Visibility reductions should only be around 4-5 miles for KTRK, KTVL, and KMMH. By late Saturday into Sunday, more westerly flow develops and may bring additional smoke and haze to the western Nevada terminals. This will be heavily dependent on wildfire activity over the next couple of days. For now it appears that the `old smoke` is just lingering about the region. -Edan && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ For more information from the National Weather Service visit...
Area Forecast Discussion
National Weather Service Las Vegas NV
Issued by National Weather Service Flagstaff AZ 750 PM PDT Fri Oct 2 2020 .SYNOPSIS...A strong ridge of high pressure over the Western States will lead to near-record high temperatures through Saturday. North breezes can be expected through this evening, especially down the Colorado River Valley. Conditions will remain warm and dry through the at least Thursday. && .UPDATE...Made some minor changes to sky cover overnight as some some thin high clouds are moving southward into the region. Also adjusted the coverage of haze/smoke in far western portions of the forecast area through Saturday. .SHORT TERM...Tonight through Sunday. Operational models are in good agreement showing the strong high pressure to remain centered over southern Nevada and south central California through Sunday. This will allow afternoon high temps to be around 10 degrees above normal for the dates. Breezy north winds have developed down Colorado River Valley this afternoon. Light and variable winds are then expected through the weekend. The HRRR Smoke Forecast continues to show wildfire smoke from the southern Sierra to impact the northern portions of the Owens Valley tonight into Saturday. Sundays weather is pretty much a carbon copy. .LONG TERM...Monday through Friday. The warm high pressure system is expected to slowly weaken and push eastward through Tuesday night. Thus expect the dry weather to continue, through max temps to lose a degrees or two each day. Progs are suggesting a return to southwest flow aloft starting Wednesday that may persist through Friday. Thus dry weather is expected as well as the cooling trend in afternoon temps. && .FIRE WEATHER... Strong high pressure will bring near record high temperatures through Saturday. Max temperatures will start a slow cool down on Sunday that lasts through next week, but will still be around 5 degrees above normal on Wednesday. Dry conditions to persist, with single digit RHs in the afternoon and poor to moderate recoveries overnight. Other than some gusty northerly winds down the Colorado River through this evening, the remainder of the area is expected to see typical diurnal winds. && .AVIATION...For McCarran...Generally diurnal wind patterns and clear skies are forecast through Saturday evening. For the rest of southern Nevada, northwest Arizona and southeast California...Little impacts expected through Saturday evening. Smoke is expected to stay west of the Owens Valley through this evening, but there is potential for smoke to move into this 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. && $$ UPDATE...JJ DISCUSSION/AVIATION/FIRE WEATHER...41 && For more forecast information...see us on our webpage: or follow us on Facebook and Twitter