Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/05/20

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
522 PM MDT Sun Oct 4 2020 .AVIATION... 00Z TAF CYCLE VFR conditions prevail and are forecast to persist, although with hazy skies. Some vsby reduction in smoke/haze is possible at KGUP and KFMN by Monday afternoon, although forecast to remain VFR at this time. Otherwise, westerly winds will get a bit gusty Monday afternoon. 11 && .PREV DISCUSSION...259 PM MDT Sun Oct 4 2020... .SYNOPSIS... Record and near record high temperatures are expected daily for the remainder of the week as a ridge of high pressure gradually shifts eastward over the state. On Monday, winds will become gusty enough for some fire weather concerns over the east central highlands. Winds will strengthen areawide next weekend, and there will be a chance for rain and snow showers mainly in the mountains near the Colorado border, as a disturbance crosses the central Rockies. && .DISCUSSION... SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)... Northwest flow aloft will increase over NM tonight and Monday as a weak upper level wave shifts quickly southeast thru the region. Min temps tonight will be chilly again over central and western NM with strong inversions. The eastern plains will trend several degrees warmer with lee side troughing deepening along the Front Range. Deep mixing Monday afternoon will tap stronger winds aloft and lead to breezy northwest winds from Farmington to ABQ and Clines Corners. High temps will warm 10 to 15F above normal and a few record highs are possible. Stronger winds, single digit humidity, and warm temps with deteriorating drought conditions will increase fire danger over much of the area. The most recent HRRR smoke guidance shows a large area of elevated smoke/haze over the Great Basin shifting over NM again Monday afternoon. Lighter winds and clear skies Monday night will lead to more chilly temps with strong inversions. Guyer LONG TERM...(TUESDAY THROUGH SUNDAY)... Record and near record warmth is forecast to continue for the remainder of the week as the western US ridge of high pressure shifts eastward over the state while gradually weakening. Winds will strengthen this weekend as an upper level trough crossing the central Rockies strengthens southwest flow aloft and a sharp surface trough develops in the lee of the southern Rockies. A few rain and snow showers could develop near the CO border Sunday as a Pacific cold front dives through the state, but the main concern will probably be critical fire weather conditions since humidities will remain very low and temperatures will remain above normal in most places. 44 && .FIRE WEATHER... Critical fire weather conditions will develop Monday in the area from the Sandia/Manzano Mts east to Clines Corners. Another upper level high center will drift over NM through the remainder of this week with warm temps, low humidity, and lighter winds. A potential pattern change is on the horizon by this weekend as a large scale upper level trough approaches from the PacNW. Unfortunately, the expected impacts from this system will most likely be just stronger winds across NM for a few days. Guyer && .ABQ WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch Monday afternoon for the following zones... NMZ107. && $$
Area Forecast Discussion
National Weather Service Boise ID
847 PM MDT Sun Oct 4 2020 .DISCUSSION...Satellite and webcams showed smoke slowly clearing across northwest portions of the forecast area late this afternoon and evening. Clearing will push southeast overnight as a weak cold front and northwest winds aloft bring cleaner air into the area. Monday should arrive with decreased smoke across most areas, but may linger across far southern portions of Oregon and Idaho. Temperatures on Monday will be 3-7 degrees cooler than today. Skies will be sunny with locally breezy winds through the Snake River Plain. No updates this evening as the forecast remains on track. && .AVIATION...VFR, except smoke layers may reduce visibility to around 5 miles in some areas. Surface winds: variable 10 kt or less overnight, becoming W-NW less than 10 kt Monday afternoon. Winds aloft near 10kft MSL: W-SW 10-20 kt. && .PREV DISCUSSION... SHORT TERM...Tonight through Tuesday night...Satellite imagery shows smoke already clearing in Baker County/OR. Latest HRRR smoke model continues to clear out the smoke from NW to SE tonight through Monday night as flow aloft becomes northwesterly. Southern Harney and Malheur Counties and Idaho south of the Snake Basin may not fully clear before upper flow again backs to westerly late Monday night and Tuesday and begins to bring the smoke back in. Max temps will be a dew degrees lower Monday, then 2 to 5 degrees higher again Tuesday with the larger warming on the Oregon side. Breezy this evening in southeast Oregon and southwest Idaho, and again Monday afternoon in south-central Idaho, otherwise light winds through Tuesday. LONG TERM...Wednesday through Sunday...Warm and dry conditions are expected through Friday before an approaching system brings increased clouds, winds and precipitation for Saturday and Sunday. Models still differ on the arrival time of precipitation, but expect up to 0.75-1.00in of precipitation over the mountains with generally under 0.50in in the valleys with this system. Snow levels will lower to around 6000-7000ft, with temperatures around 10 degrees below normal as the core of the system moves over. Upper level ridging returns after Sunday with a return to dry conditions. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ DISCUSSION...ST AVIATION.....SP PREV SHORT TERM...LC PREV LONG TERM....KA
Area Forecast Discussion
National Weather Service Charleston SC
907 PM EDT Sun Oct 4 2020 .SYNOPSIS... High pressure will build into the region tonight and prevail through Thursday. A coastal trough will form Tuesday and move out to sea by Wednesday bringing some showers mainly near the coast. An upper level disturbance may bring unsettled weather to the area Friday through Sunday. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... The forecast is on track and required only very few adjustments. Mesonet observations around Darien have finally recorded 0.01" over the past hour. High pressure centered over the Mid-Mississippi Valley will build south and east tonight in wake of passing shortwave energy crossing the Ohio Valley. A weak frontal wave riding northeast along a weak stationary front offshore off the Southeast U.S. coast will move farther away from the region tonight. KCLX is still pinging some light returns along the Georgia coast, but mesonet observations from Saint Simons to Tybee Island have not registered any rainfall today. This suggests this activity is falling as virga or light sprinkles with the latest RAP sounding at Sapelo Island still showing a fairly deep mid-level dry layer between 850-500 hPa. Did opt to hold onto some slight chance pops along the Georgia coast for a few more hours, but these should end as the front pushes farther to the east and isentropic downglide commences. Lows from the lower 50s well inland to the lower 60s along the beaches still look on track. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Monday through Wednesday: Dry surface high pressure will prevail through the period and rain-free conditions are expected on Monday. By Tuesday morning, a coastal trough enters the waters from the south, even trying to develop into a closed low off the Charleston County coast by Tuesday afternoon. Low-end chance PoPs have been placed along the coastline during the daytime period with most of the rainfall occurring offshore and diminishing Tuesday by sunset. Southeasterly H85 winds will begin to advect offshore moisture into the region Tuesday night into Wednesday, with 70F+ dew points creeping into the SE GA counties. Wednesday should remain rain-free for much of the forecast area, however slight chance PoPs were placed over the SE GA counties due to the increase moisture and instability. High temperatures will remain near normal Monday and Tuesday mid to upper 70s. Temps are expected to be slightly warmer Wednesday due to clearing skies and westerly downslope flow, with highs in the low to mid 80s. Monday and Tuesday night min temps range from low/mid 50s to the mid 60s nearest the coast. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Reinforcing high pressure will build from the northwest late week, then set up a cold air damming regime over the weekend as it pushes into New England. A developing upper trough and increasing moisture streaming out of the Gulf of Mexico will likely result in an increase in rain chances Friday through Sunday. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... VFR. Extended Aviation Outlook: Tuesday into Wednesday morning, flight restrictions are possible in low stratus, otherwise VFR conditions expected to prevail through the week. && .MARINE... Tonight: North to northeast winds will average 10-15 kt overnight as high pressure builds in. Seas will range from 2-4 ft nearshore waters to 4-5 ft offshore waters. Monday through Friday: A N to NE flow will persist before turning SW overnight Wednesday for a brief period, then returning to NE flow for the remainder of the week. Wind gusts could approach Small Craft Advisory (SCA) criteria in all waters Monday through Monday night, especially in the outer GA waters. Gusts could again approach SCA criteria on Friday as the pressure gradient tightens. SCAs are not anticipated at the moment. Seas will generally range from 2-4 ft in the nearshore waters and 4-5 ft in the outer GA waters, and decreasing to 2-3 ft in all waters near mid-week. Following the increasing trend in winds, seas will then begin to build throughout the day on Friday. && .TIDES/COASTAL FLOODING... There is a very low chance that tides could reach marginal Coastal Flood Advisory levels again during the Monday morning high tide along the SC coast. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$
Area Forecast Discussion
National Weather Service Green Bay WI
1000 PM CDT Sun Oct 4 2020 New Information added to update section .UPDATE... Issued at 959 PM CDT Sun Oct 4 2020 Temperatures have dropping into the 30s across much of Door County, so have added them to the Frost Advisory overnight. && .SHORT TERM...Tonight and Monday Issued at 242 PM CDT Sun Oct 4 2020 The latest RAP analysis and satellite/radar imagery show surface high pressure stretching from western Lake Superior to the southern Plains early this afternoon. Diurnally enhanced convective clouds are holding tough over northern WI thanks to moisture fluxes off Lake Superior and northern Lake Michigan. Clouds further south over central and east-central WI have been eroding, except near the Lake Michigan shoreline. With further mixing into dry air, should see the clouds dissipate by late afternoon. Looking upstream, mostly clear skies are present near and west of the surface high. As this high moves across the region tonight and west of the region on Monday, forecast concerns mainly revolve around frost potential and gusty south winds. Tonight...High pressure will slide across the region during the evening to the central Great Lakes overnight. Most of the evening will see clear skies and light winds, which will promote tumbling temperatures. Some mid and high clouds do invade far northern WI overnight, while boundary layer winds start to increase over central and north-central WI. But conditions should be supportive for a long enough time to generate frost over much of the region. With agricultural interests determining that the growing season has ended over central WI, will issue a frost advisory for parts of far northeast and east-central WI, excluding Door County. Lows will generally range from upper 20s to mid 30s away from the Lake. Monday...Southwest winds will be strengthening ahead of a weak cold front moving across the northern Mississippi Valley. Strong gusty winds to 35 mph can be expected, peaking late in the afternoon. Otherwise, should see ample sunshine, with only some scattered mid and high clouds overhead at times. The southwest winds will usher in warmer air, with highs ranging from the mid 50s to lower 60s, which is near normal for the date. .LONG TERM...Monday Night Through Sunday Issued at 242 PM CDT Sun Oct 4 2020 An upper trough and Pacific cold front could produce a few sprinkles or very light showers as it moves across the area Monday night. Clouds and a steady breeze will hold temperatures up Monday night. After a breezy and milder day Tuesday, a more vigorous upper trough and accompanying weak cold front has a little better chance of producing showers across northern Wisconsin Tuesday night, but the best dynamics are across Upper Michigan. Highs will be about five degrees above normal. Dry and mild weather is expected Wednesday through Saturday. There is a small chance that some showers could accompany a warm front moving north across the region Friday, but not sure at this point. && .AVIATION...for 00Z TAF Issuance Issued at 637 PM CDT Sun Oct 4 2020 Wind/LLWS will be the main concerns during this TAF period. Diurnal cumulus/stratocumulus have eroded rapidly early this evening, leaving clear to partly cloudy skies. Winds were light and variable due to a surface ridge of high pressure residing over the forecast area. The surface ridge will shift east overnight, allowing south to southwest winds to develop. The winds aloft will increase first, resulting in LLWS at the RHI/AUW/CWA TAF sites late tonight into Monday morning. By 15z-16z/Monday, surface winds will increase significantly, with gusts to near 30 knots expected through the afternoon. As the surface winds decrease Monday evening, LLWS will ramp up again. VFR conditions will prevail through the entire TAF period. && .MARINE... Issued at 242 PM CDT Sun Oct 4 2020 Gusty northerly winds will cause conditions hazardous to small craft through the end of the afternoon. Buoys over the northern Lake have been consistently running in the 4-6 ft range so far today, though those higher waves are most likely further out towards the open waters and not right up against the shoreline. The area will be in between a departing high to the southeast and an approaching low pressure system to the northwest Monday and Monday night. This will bring gusty south winds to the Lake Michigan waters Monday afternoon and Monday night. Winds could gust to gale force at times, especially around the Door Peninsula late Monday afternoon and evening. Gale headlines may be needed in subsequent forecasts if these wind gusts maintain themselves or increase. Winds do not look quite as strong on the Bay, but may approach gale force for a few hours late in the afternoon into early evening as well. Will let the current small craft advisory expire before issuing headlines for Monday. && .GRB WATCHES/WARNINGS/ADVISORIES... Frost Advisory until 8 AM CDT Monday for WIZ020-022-031-037>040- 045-048>050-073-074. && $$ UPDATE.........Kieckbusch SHORT TERM.....MPC LONG TERM......RDM AVIATION.......Kieckbusch MARINE.........MPC
National Weather Service Jackson KY
727 PM EDT Sun Oct 4 2020 .UPDATE... Issued at 727 PM EDT SUN OCT 4 2020 Line of showers has filled in this evening so bumped up pops accordingly, but all of this activity will be exiting to the east in the next 2 to 3 hours, with cold/dry advection kicking in behind the cold front. There is quite an extensive area of low clouds back to the northwest behind the front and this stratus will overspread the area by late this evening or midnight. RAP hangs onto the moisture associated with these clouds through much of the night and with upslope flow, this may be a reasonable forecast. Thus, going to beef up the clouds more late tonight, which will likely limit valley fog. Also with a weak gradient continuing overnight, fog may struggle even if it did clear. Forecast update has been saved and sent. && .SHORT TERM...(This evening through Monday night) Issued at 409 PM EDT SUN OCT 4 2020 A cold front stretched through KY from a little east of KCVG to KBWG late this afternoon. It was producing some showers which were still just to the west of the JKL forecast area, with the greatest concentration of showers along the northern extent of the boundary. The front will progress southeast, and exit out of the state later this evening. Showers will affect some locations, with the greatest concentration expected to continue in the north. Even there, only chance POPs were in order. Clouds will increase as the front approaches and moves through, and last into the night. The extent of clouds and dry air advection behind the front will determine our fog potential for tonight. Valleys will be most likely to hold on to low level moisture during the night, and if the clouds break to a great enough extent, fog would be expected, especially in the deeper valleys in southeast KY. Any fog will dissipate on Monday morning, and as diurnal heating occurs, mixing will also break up any clouds. Dominating high pressure moving in from the northwest will then bring clear skies Monday night. Forecast dew points no lower than around 40 will limit our low temperatures on Monday night. Otherwise, frost could be a concern as the high passes over. .LONG TERM...(Tuesday through Sunday) Issued at 310 PM EDT SUN OCT 4 2020 The extended period will feature a large area of high pressure that will bring dry and steadily warming temperatures to eastern Kentucky from Tuesday onward. Daytime highs will range from the mid to upper 70s for most locations, while nightly lows will range from the upper 40s to the mid 50s. Mostly clear skies and light and variable winds will also be on tap, as high pressure takes hold. The latest model data tries to bring some rain into the area from early Saturday morning through Saturday evening. This rain would be associated with a tropical system that is forecast to form over the Caribbean Sea this week and then perhaps move through central Gulf of Mexico and eventually northeastward through Tennessee Valley. However, this a low confidence part of the forecast. Therefore, we left in only minimal slight chance PoPs across the southern half of the forecast area from around dawn Saturday through late Saturday evening. Aside from that, the weather for eastern Kentucky should be dry, with a steady warm up taking place through out the week. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 727 PM EDT SUN OCT 4 2020 A cold front will bring shift the very light southwest winds to the northwest this evening, but winds should generally remain 5 knots or less at the TAF sites. A line of showers associated with the cold front will impact areas from KJKL to KSJS through about 01z, before exiting. The more relevant aviation concern tonight is the area of MVFR cigs associated with some low stratus that will overspread the area by late this evening and continue through much of the overnight hours. These MVFR cigs will quickly erode through the morning hours on Monday giving way to VFR conditions. There remains some question as to how fast the clouds will erode either late tonight or tomorrow morning. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...HAL LONG TERM...AR AVIATION...KAS
Area Forecast Discussion
National Weather Service Medford OR
853 PM PDT Sun Oct 4 2020 .UPDATE...With higher moisture in the region, especially over the west side, stratus should be inland further into the Umpqua basin. Otherwise, expect a repeat of last night tonight. Current forecast looks on track and will not update this evening. Sven && .AVIATION...For the 05/00Z TAFS...VFR conditions prevail across the area this afternoon. The exception is along the coast from Brookings south where LIFR conditions persist due to coastal stratus. Also, there are some MVFR/IFR vsbys around due to wildfire smoke, in northern California and across southeastern portions of Lake County. Expect the current conditions to prevail through the TAF period with little change expected for most areas. Marine layer stratus will return to coastal areas again late this evening and overnight. However, coverage will be less extensive and increasing offshore (east to northeast) flow will likely lead to earlier clearing of the marine layer compared to recent days, especially north of Cape Blanco. /BR-y && .MARINE...Updated 800 PM PDT Sunday 4 October 2020...The thermal trough will continue to strengthen into Monday evening, producing stronger north winds and building wind waves. The wind seas are combining with a moderate west swell to produce steep seas south of Cape Blanco this evening, then spreading to the rest of the coastal waters late tonight into Tuesday morning. Seas may become very steep and approach warning levels south of Cape Blanco and beyond 10 nm from shore Monday afternoon. Winds diminish as the thermal trough shifts inland Tuesday into Wednesday. Seas will actually build slightly on Tuesday as the transition from wind wave to fresh swell is accompanied by modestly building longer period northwest and south swells. Improvement in conditions will be brief, from Wednesday into early Friday. A pattern change to more active weather is expected this weekend. Expect periods of increased southerly winds that will likely result in at least advisory level conditions as multiple fronts move through the area. && .PREV DISCUSSION... /Issued 259 PM PDT Sun Oct 4 2020/ DISCUSSION...Stubborn low clouds and fog continue to affect areas from Pistol River southward this afternoon as well as in portions of Coos and NW Douglas Counties. Weak offshore east winds develop over the coastal mountains tonight and continue into Monday morning in response to a rebuilding offshore ridge and a strengthening surface thermal trough in NW CA/SW OR. This could allow stratus/fog to dissipate near Brookings. But, given the time of year, not sure the winds will be strong enough to completely clear, especially with a coastal eddy present just offshore to the south. So, have left patchy clouds/fog in there overnight. Still expecting stratus/fog to linger/reform in Coos and western Douglas County and could be some that develop in the Umpqua Valley near Roseburg toward sunrise. Other than that, it`ll be clear with some smoke/haze persisting in northern California and east of the Cascades. Models continue to show a dry, warm pattern continuing across the area through at least the middle of the new work week. Recent runs of the HRRR smoke model have been unavailable, but previous ones have suggested the potential for at least some high level smoke returning to the north, including Medford, Monday afternoon/evening with thicker smoke persisting across NorCal. We should expect at least hazier conditions on Monday compared to today with the possibility of some degradation in air quality, especially for areas of higher terrain. Overall, high temperatures will be about 10 degrees above normal. Expect similar conditions to persist through Wednesday. The upper ridge will begin to break down late this week (Thu/Fri) resulting in daytime temperatures gradually lowering closer to seasonal normals along with an increase in humidity. Models and ensembles continue to show a transition to a cooler, wetter pattern later Friday into the weekend, but not without some changes. Recent guidance is showing the flow splitting initially, allowing the lead shortwave disturbance coming in from the Pacific Friday to head into California. This lowers confidence a bit as we head into next weekend, but a strong 170+ jet across the north Pacific should lead to a potent trough and cold front moving through the PacNW Saturday. So, while not a complete "lock", we do think wetting rains are likely across a large part of the area next weekend. One thing to note is that the system next weekend will be moving quickly and latest model data suggest that rainfall probably won`t be heavy enough for burn scar flooding/debris flows - mostly beneficial though to help bring this unrelenting fire season to an end. Of course, it`s still 6 days away, so we`ll be monitoring the model trends and updating the forecast as we get closer. -Spilde FIRE WEATHER...Updated 1 PM PDT Sunday, October 4th, 2020...The fire weather environment remains significantly warm and dry through Wednesday. High temperatures 10 to 20 degrees above normal will continue, and overnight ridgetop humidity recoveries continue to be moderate to poor...with low daytime humidity in most locations. A Red Flag Warning remains in effect for portions of FWZ 285, the Modoc, for this afternoon and evening for gusty west winds and low humidity. With fuels near record dryness for this time of year, today is certainly a watch out day there. East winds are still expected tonight into Monday morning and then again Monday night into Tuesday morning, most notable along and near the Curry County coast and out toward Slater Butte in western Siskiyou County. However, while notable due to the ongoing fires, this is a light event in which peak wind gusts are most likely to be in the 15 to 25 mph range through the east to west oriented gaps and passes. As the air RH recoveries are expected to be the lowest of the week on Tuesday morning. The general winds aloft turn southerly Tuesday afternoon and increases into Thursday. The last of the very dry days will likely be Wednesday, so we`ll be watching that day for potential Fire Weather Watch in the next few days. Latest model data suggests that windy conditions on the ridgetops won`t materialize on Friday, contrary to the previous data, so please stay tuned. Any strong winds, even with higher humidity, could bring down snags or drought- stressed trees and pose safety risks to any ongoing firefighting or rehabilitation efforts. Wetting rains are still likely sometime between Friday to Sunday, though latest model data brings the first rainmaker Friday mainly south of our forecast area into Central California. This generally lowers our confidence some for widespread wetting rainfall over the weekend, but it`s still 60-70%, highest from Cascades westward...and lowest east of the Cascades. We do expect another system to move in on Saturday and bring significant rainfall with it. One additional note is that latest model data has suggested less of a threat for burn scar flooding, but we`ll keep an eye on trends as we move forward. Keene/BTL && .MFR WATCHES/WARNINGS/ADVISORIES... OR...None. CA...None. Pacific Coastal Waters...Small Craft Advisory until 5 PM PDT Wednesday for PZZ356-376. Small Craft Advisory from 2 AM Monday to 5 PM PDT Wednesday for PZZ350-370. $$ SBN/SBN/SBN
Area Forecast Discussion
National Weather Service Pueblo CO
239 PM MDT Sun Oct 4 2020 .SHORT TERM...(This evening through Monday) Issued at 238 PM MDT Sun Oct 4 2020 The main short term forecast concern is the potential for critical fire weather conditions in some areas on Mon. Dry weather will continue tonight and Mon. On Mon, an upper moving through the northern and central plains states, will send a dry front into southeast CO. The HRRR shows the winds over the far southeast plains increasing later in the morning hours, especially over Kiowa County. Winds along the I-25 corridor are expected to be northerly in the early afternoon, just not as strong as the eastern border areas, and then should become more easterly through the afternoon. RH values will be low across all of southern CO on Mon, with generally 10% or lower at the lower elevations, and the fuels are dry. At this time, it looks like Kiowa County could see the combination of RH values of below 15% and strong enough wind gusts by about 17Z, and these critical conditions continuing through the afternoon in that area, and will issue a Red Flag Warning for this area. By late afternoon, far eastern portions of El Paso and maybe some of Crowley County could also see the stronger wind gusts that will put them into the critical category for fire weather concerns, as well as a part of western Saguache County. However, these areas are not expected to see widespread critical conditions for a long enough period to warrant a fire weather highlight. Temps on Mon will be above average with highs mostly in the 80s over the plains and in the 70s in the high valleys, with upper 60s to lower 70s in Teller County. .LONG TERM...(Monday night through Sunday) Issued at 238 PM MDT Sun Oct 4 2020 High pressure will continue to build into the area starting Monday night into Tuesday. The upper-level ridge will persist but will flatten out Thursday and Friday before rebuilding slightly through the weekend. Weather is expected to be dry and quiet through the week, and daytime temperatures should remain slightly above normal, with highs in the upper 80s to low 90s over the plains and 60s-70s over the mountains and valleys. Our first chance of a change to the existing pattern sets in on Sunday, where an upper-level trough is expected to dig through Colorado through next Monday or Tuesday, bringing with it the chance of precipitation over the mountains as we head into next week. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 238 PM MDT Sun Oct 4 2020 VFR conditions are expected through the forecast period at KCOS, KPUB and KALS. Winds will generally be under 10 kts overnight. KCOS should see northerly winds increase in the late morning or early afternoon Mon with gusts near 20 kts, the becoming more easterly by late afternoon. KPUB should see winds become northerly in the late morning hours on Mon and then become more easterly in the afternoon, mainly 10-15 kts with possibly some stronger gusts toward late afternoon. && .PUB WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from 11 AM to 6 PM MDT Monday for COZ234. && $$ SHORT TERM...28 LONG TERM...GARBEROGLIO AVIATION...28
Area Forecast Discussion
National Weather Service Riverton WY
451 PM MDT Sun Oct 4 2020 .SHORT TERM...This evening through Monday night Issued at 117 PM MDT Sun Oct 4 2020 The stubborn ridge will flatten a bit today, with the midlevel flow becoming more westerly over the area. This is still a dry and warm regime, and in fact, high temperatures will be even warmer today (10 to even 15 degrees above normal in some places). The westerly flow will not only advect warmer temperatures, but more smoke as well. The HRRR smoke model shows a significant increase in smoke over the area today, before being mostly ushered out by a weak cold front tonight. Speaking of smoke, elevated fire weather conditions are expected today as the west wind picks up and RH values drop to near critical values. While some places may reach RH or wind thresholds for critical fire weather, confidence is not high that these thresholds will overlap. For now, we will continue with a Rangeland Fire Danger statement for areas in southern Wyoming and will closely monitor conditions early this afternoon. By Monday morning, a weak cold front will drop into eastern and central Wyoming as a dry shortwave clips the area. This will lower highs east of the Divide Monday...but they will still be 5 or 6 degrees above normal. This front will also bring slightly more low level moisture, increasing RH values across central and northeastern areas. Southwestern Wyoming will not get the front and accordingly will not get the moisture. In fact, RH values are expected to be in the 10 to 15 percent range across these areas. With an increased west to northwest wind, we do expect critical fire weather conditions Monday afternoon. .LONG TERM...Tuesday through Sunday Issued at 117 PM MDT Sun Oct 4 2020 Upper level northwest flow will reestablish itself over the region Tuesday. Dry and unseasonably warm conditions will continue through forecast period. In addition, elevated to near-critical fire weather conditions will continue through the week. This will be due to critically low RH values and breezy afternoon winds. Upper level flow will turn to the southwest by Wednesday, as the ridge axis shifts eastward. Record highs will be possible Thursday, as the dry, southwest winds continue to warm the region. Models continue to prog a pattern change by next weekend, with a major Pacific storm moving onshore over the West Coast Friday night. The ridge axis will shift over the Rockies as a result. Also, upper level flow will strengthen from the southwest Friday. Red Flag conditions look likely Friday under this pattern. Saturday is looking less likely, as the timing of the front could impact the area on Saturday. This would result in higher humidity, as precipitation chances increase (especially over far western portions). Precipitation chances will continue to increase across the west Saturday night, as the system digs southward toward the Four Corners region. Cooler with chances for precipitation will spread eastward through the overnight hours, as the system moves over the Cowboy State Saturday night. This will likely be a valley rain/mountain snow event, as we are not looking at a bitterly cold system. 700mb temps are looking to be in the 0 to -4C range with the onset of the system. Greatest impacts will likely be across the west and mountains, with much colder temperatures. && .AVIATION...For the 00Z TAFS through 00Z Tuesday VFR conditions will prevail through the period. Winds will subside by 01Z in most locations. A few sites will have a sustained wind 10+ kts through the overnight hours. A cold front will progress southward east of the Divide after 12Z Monday, with winds turning north-northwest in response to the frontal passage. Gusty winds will return after 18Z, mainly impacting KBPI, KPNA, KRKS and KCPR. && .FIRE WEATHER... Issued at 117 PM MDT Sun Oct 4 2020 Westerly flow returns today, as the ridge aloft flattens out. This will bring drier and gustier winds to the state, especially across southern WY. Elevated fire weather conditions are expected for 277, 278, 279, and 289 this afternoon. A Rangeland Fire Danger statement has been posted for those areas. Will monitor for further wind increases, which may push conditions to near- critical for 289 and the eastern portions of 279 late this afternoon. A cold front will move across areas east of the Divide on Monday, bringing brief gusty north winds and increasing moisture. This will limit the fire weather threat for most of northern and central WY. Southern WY will remain in the dry and breezy regime, with humidity levels below 15 percent and gusts of 20 to 25 mph possible. A Red Flag Warning is now in effect for 277, 278, and 279 through Monday afternoon. && .RIW WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from noon to 7 PM MDT Monday for WYZ277>279. && $$ SHORT TERM...Myers LONG TERM...LaVoie AVIATION...LaVoie FIRE WEATHER...Straub/Myers