####018004269#### FXUS63 KPAH 032325 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 625 PM CDT Fri May 3 2024 .KEY MESSAGES... - Warm temperatures continue this weekend and through next week. - Unsettled weather pattern through next week with scattered showers and storms Saturday through Monday, and more widespread storms Monday night through Thursday. - Potential exists for severe thunderstorms and heavy rainfall next week. && .DISCUSSION... Issued at 240 PM CDT Fri May 3 2024 Upper level troughing will remain to our North and West with several disturbances advancing through the region helping to bring scattered showers and storms this weekend and into next week. This afternoon a weak disturbance is moving across the area helping to generate some scattered shower activity. Wind fields aloft are weak, so not expecting much any organization this afternoon and into tonight. The loss of forcing, and nocturnal stabilization should lead to mostly dry conditions tonight. A northern stream disturbance moves across the northern plains Saturday into Sunday. A few weak impulses are progged to move across the region leading to scattered showers and storms within a moist and unstable airmass. Overall, the lack of shear should keep severe potential low, although an isolated strong to severe storm is possible across SEMO Saturday afternoon/evening. Our attention then turns toward a few days of more active weather Sunday into the middle of next week. A more robust shortwave lifts from the southern plains with a weak boundary draped across the Quad State Sunday night into Monday. Better synoptic scale forcing combined with an unstable boundary layer should lead to more widespread showers and storms during this period. Unlike today and Saturday, mid level flow will be slightly stronger as a 30-35 knot mid level jet noses into the area. Deep layer shear approaches 30 knots which may lead to some organized convection, although the current thinking is that these potential storms will be more isolated in nature. The upper levels amplify Monday night into Tuesday as a sharp upper trough digs into the northern plains. Shortwave ridging developing over the region may keep things more isolated Monday into Tuesday morning. Tuesday will be breezy as low level winds increase associated with strong mid/upper level flow. Winds could approach 30 mph during the afternoon. Still need to watch for severe weather potential Tuesday into Thursday associated with a more amplified upper level pattern and a good overlap of shear and instability. Deep layer troughing will develop across the Rockies and move into the plains states. Still some questions on when the greatest time-frame for severe weather but there seems to be an increasing signal on the Wed-Thu time- frame. An area of low pressure develops across OK/TX and lifts northeast into Missouri. Increasing divergent flow aloft will overspread an increasingly moist and unstable airmass with dewpoints likely approaching or exceeding 70 degrees. Increasing southwest flow aloft will translate to increased deep layer shear for organized severe weather. All modes of severe weather appear possible at this time. Later forecasts will be able to fine tune timing of severe weather. Additionally, will also need to keep an eye on flooding concerns with several rounds of convection possible through next week. Drier weather arrives Friday post fropa and with increasing zonal flow aloft. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 612 PM CDT Fri May 3 2024 Some lower MVFR clouds are possible at the eastern terminals around morning. Cloud cover is tricky with this forecast as none of the models are doing very well. If clouds clear out more over CGI and MVN then fog may be likely to form in those areas. Winds will be light and variable for the most part, then out of the southwest tomorrow. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ DISCUSSION...AD AVIATION...SHAWKEY ####018010961#### FXUS63 KLBF 032326 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 626 PM CDT Fri May 3 2024 .KEY MESSAGES... - Strong to severe thunderstorm development is expected Friday afternoon and evening with damaging wind gusts and locally heavy rainfall the main concerns. - Another episode of severe weather appear increasingly likely for Monday, but confidence in impacts in the local area is low at this time. - Cooler temperatures are likely for Day 5 (Tuesday) and beyond. && .SHORT TERM /THROUGH TONIGHT/... Issued at 243 PM CDT Fri May 3 2024 Immediate concern focuses on the threat for severe thunderstorms this afternoon and evening across much of western Nebraska. As of 19z, convection was developing along a stationary boundary draped from the southern Panhandle into north central Nebraska or roughly just north of a SNY to just south of a VTN line. Ahead of this feature, strong southerly flow was driving low-level convergence in immediate proximity to the boundary. Moisture in the warm sector is marginal at best with dew points reading the upper 30s to low 40s as air temperatures read the upper 60s to lower 70s south of Highway 2. This will greatly limit instability with MLCAPE values only progged to approach 1000 j/kg for areas south of Highway 23. Further north, values will likely remain 750 j/kg or less with rapid decrease with northward extent. Even so, forcing should be fairly strong with the frontal boundary progressing through the area. At the same time, flow aloft remains fairly strong with h5 flow exceeding 40 knots. With southerly surface flow, this is producing moderate 0-6km BWD values of 40 to 50 knots. Forecast soundings show inverted-v profiles ahead of the main line of convection but with a lack of drier air aloft, max theta-e values are marginal only falling to around minus 10 degC. At the same time, DCAPE values are on the lower end as well with most locations reporting values of less than 750 j/kg. That said, flow off the surface immediately following the frontal boundary will respond accordingly as a strengthening cold pool drives this south quickly this evening. These elevated winds will likely be efficiently mixed to the surface by the convection. This will support at least a concern for isolated damaging wind gusts in the local area. While hail cannot be ruled out, believe this threat is fairly low given lack of greater instability aloft. As forcing translates east along the boundary, increasing moist advection will help increase coverage of thunderstorms on approach to southwest and eventually central Nebraska later this evening. Coverage should blossom as a result with a growing concern of locally heavy rain. While PWATs remain low, less than 0.75", rain rates exceeding 0.50"/hour with potential for training storms should lead to a smaller area of QPF likely exceeding 1.00" from southeastern Lincoln/Frontier Counties up through central Nebraska to include southern Custer County. These areas have recently seen fairly heavy rainfall events as departures from normal values exceed 150% and even approaching 300% for some of these locations. This has helped drive county based Flash Flood Guidance to around 1.5"/2.0" for the 1 hour/3 hour values respectively. Latest HREF guidance shows Probability Matched Mean values of 3 hour QPF exceeding 1.25" for many of the mentioned areas and even peaking around 2.0". This suggests some hydrology concerns so this will need monitored as the evening progresses. Believe incoming dry air behind the front and the main source of lift should clear the area by Midnight Friday night though lingering stratiform precipitation could last into the early morning hours Saturday. This later departure of clouds and precipitation should help keep overnight lows across our east on the milder side with its implications on any frost threat covered at the start of the long term discussion below. && .LONG TERM /SATURDAY THROUGH FRIDAY/... Issued at 243 PM CDT Fri May 3 2024 Saturday and Sunday...Departing trough to the northeast will allow mid-level heights to rise as shortwave ridging builds in its wake. This will promote dry conditions for Saturday as surface high pressure settles through the area. Forecast lows for Saturday morning do not line up with latest guidance on vulnerable vegetation therefore thinking no frost headlines are needed at this time. Supporting this thought is steady northerly winds with potential for lingering low stratus across our eastern zones. Admittedly, the residual cloud cover behind a progressive cool front tends to be overstated in NWP guidance. Even with the more pessimistic guidance though we see steady enough flow in the low-levels to prevent full boundary layer decoupling with surface winds remaining in the 10 to 15 mph range through sunrise. Further west where the setup for radiational cooling will be more favorable, lows will again fall below the freezing mark. That said, the areas remain outside the latest guidance for susceptible vegetation therefore no Frost or Freeze headlines are expected. All that said, lows will range from the upper 20s west to upper 30s east. Daytime highs will climb into the low to middle 60s with light and variable winds generally 15 mph or less through the daytime. Ridge breakdown begins Sunday as the next shortwave trough approaches the central Rockies late in the day. With developing surface low to the west and departing high pressure to the east, a west to east pressure gradient will compress locally and help drive some increasing southerly winds late Saturday into early Sunday. This will promote increasing moisture advection into the area. This will also favor a fairly stubborn low stratus deck across our western zones that may struggle to clear out until later in the day. As a result, cool temperatures will remain stubborn with afternoon highs remaining in the low to middle 60s. Winds will be on the stronger side for areas west of Highway 61 where gusts may climb into the 35 to 45 mph range with 25 to 35 generally expected elsewhere. Can't rule out a few light rain showers west of Highway 83 in the area of greatest moisture advection but given the general lack of convergence and limited WAA, believe this potential is fairly low with minimal if any impacts expected. Monday...A well advertised storm system will traverse the Plains, bringing with it the potential for a fairly robust severe weather episode across the region. Low-level southerly flow will persist early into the day helping increase surface moisture as a dryline tightens from western South Dakota down through western Texas. Aloft, the aforementioned shortwave disturbance will begin to take a negative tilt as it ejects onto the Plains early in the day. A concentrated area of significant height falls in concert with strengthening upper-level divergence will help foster the development of an elongated area of low pressure stretching from southern Colorado up through eastern Montana. Within the plume of richer low-level moisture, the combination of mild afternoon highs and steep mid-level lapse rates will lead to increasing instability within a strongly sheared environment. For now, greatest confidence in severe weather remains east and southeast of the local area where all hazards will be possible. Closer to the local area, expecting the greatest threat to favor large hail and damaging wind gusts. That said, the progressive cold front overtaking the dryline will encounter modest instability in our eastern zones so the prospect for severe weather affecting the local area cannot be ruled out. The latest SPC Day 5 severe weather outlook highlights areas east of Highway 83 in the 15% probability, or the equivalent of a Slight Risk (level 2 of 5). For now, have no qualms with this but impacts from morning rain and thunderstorms within the strong WAA within the warm sector and how this affects the afternoon environment will need to be closely monitored. Behind the boundary within the drier airmass invading the area, strong CAA will support windy conditions with gusts nearing the 35 to 45 mph range out of the west. Temperatures will likely falter as a result but this looks to be late enough in the day that afternoon highs will still reasonably reach the upper 50s to lower upper 60s across the area. Tuesday and beyond...mid-level heights will be quick to fill in early Tuesday as a cutoff low at h5 takes shape across the northern High Plains. This feature will likely remain fairly stagnant through the middle of the upcoming week with a slight cooling trend in temperatures expected for the later half of the forecast period. Latest ECMWF Extreme Forecast Index (EFI) guidance hints at a continuation of strong winds from Monday into Tuesday. Another cool front will traverse the area by late Tuesday into Wednesday, bringing about a more notable drop in temperatures. Some low- end PoPs will also dot the forecast, favoring areas north of Interstate 80. For now, confidence is greatest in precipitation Thursday afternoon and evening. Higher percentile values from the NBM suggest the potential for wetting rains but variances in deterministic and other ensemble guidance limits confidence in this occurring thus far. Temperatures will favor below normal values through the time frame which will include overnight lows falling to near the freezing mark. This would line up with frost/freeze climatological median dates so potential need for headlines next week cannot be ruled out. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 625 PM CDT Fri May 3 2024 Active weather continues through this evening. Thunderstorms will mainly be confined along and south of the I-80 corridor impacting KLBF. These storms have the potential to become severe with large hail, strong winds, and heavy rainfall being the primary threats. Some light fog due to increased moisture and falling rain may also cause visibility restrictions down to 2 miles at times. North of I- 80, precipitation will remain more stratiform, but visibility restrictions due to light fog and continuous rainfall is still expected. Precipitation will exit the region to the east by late evening with gradual improvement of conditions and rising ceilings into Saturday morning. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...NMJ LONG TERM...NMJ AVIATION...Kulik ####018006001#### FXUS65 KBOU 032327 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 527 PM MDT Fri May 3 2024 .KEY MESSAGES... - A few showers and storms across the eastern plains this afternoon into tonight. - Warmer and windy on Sunday. - Active, cooler, and mainly windy pattern from late Sunday through most of next week. A few chances of accumulating snow across the mountains with isolated/scattered showers across the plains. && .SHORT TERM /Through Saturday/... Issued at 303 PM MDT Fri May 3 2024 Current analysis shows a lee cyclone across the Palmer Divide area. From the north, a cold front is advancing southward with a push of gusty northerly winds behind it. Gusts 35-45 mph are being reported across the region from the front. Along this front, a line of thunderstorms moves across the northeastern plains. SPC mesoanalysis shows an axis of marginal instability across the far east plains (< 500 J/kg SBCAPE). This is overall supported by an shortwave trough moving eastward just north of the Colorado border. For the remainder of the afternoon and into the evening expect showers in the mountains with another round of showers moving across the northern border onto the plains. Areas such as Lincoln County remain unstable ahead of the advancing front, so can't rule out any shower or storm development in those areas in the next hour. Showers linger across the mountains this evening with remaining showers/storms exiting the eastern plains. Behind the front, temperatures cool sufficiently overnight with lows in the low to mid 30s across the plains. We are approaching Frost/Freeze headline territory for areas on the plains; however, given its current rating of mixed susceptibility for vegetation and closeness to average last freeze, we decided to hold off on headlines. For tomorrow, expect cooler temperatures with highs in the 60s across the plains, 50s for foothills/mountain valleys, and 40s for the mountains. Expect another round of showers and a few storms in the afternoon (marginal CAPE), mainly over the higher elevations and south of I-70. && .LONG TERM /Saturday night through Friday/... Issued at 303 PM MDT Fri May 3 2024 A strong upper low will be located near northern California on Sunday morning, with increasing south-southwesterly flow over our forecast area through the day. The result will be a warm, dry, and breezy end to the weekend as the dryline shifts towards the CO/KS/NE border. Temperatures should warm into the mid to upper 70s. Model soundings suggest boundary-layer average winds of 30-45kt, which would lead to wind gusts of 45-55 mph. Some guidance keeps just enough moisture out in the far eastern plains for an isolated shower or storm, though the models that keep some moisture here also maintain a strong cap through the day. The closed upper low is expected to transition to a sharp, negatively tilted trough axis by Monday morning... which then ejects into the northern Great Plains from Monday into Tuesday. A quick round of mountain snow is likely with the passage of the trough axis, though cross-sections show somewhat sparse moisture on this side of the trough. For the plains, a few showers will be possible, but the main story will be wind. A bora-like event appears likely as a colder westerly flow develops. Temperatures will hover in the upper 50s/low 60s. Gusty winds will continue, especially across the high country. Zonal flow is expected to persist Tuesday into Wednesday as the upper trough stalls over the far northern Great Plains. Guidance shows a bit of moisture lingering in this flow, which would lead to scattered snow showers across the high country while the plains remain generally dry. With fairly strong mid-level flow, gusty winds will be slow to subside in this period. As we get into the latter half of next week, there is increasing uncertainty in the overall synoptic pattern. Recent guidance attempts to stall out the trough or even retrograde it back to the south and west. Unsurprisingly, ensemble guidance lacks a clear, definitive signal, with a substantial amount of spread for T/QPF as we get into Thursday/Friday of next week. We'll likely have a ways to go until we see better agreement in this timeframe... but at the very least, it does appear that a cool and unsettled pattern will continue. && .AVIATION /00Z TAFS through 00Z Saturday/... Issued at 525 PM MDT Fri May 3 2024 Gusty NE winds will gradually weaken 01-04Z this evening, rotating to the southeast and likely persisting from that direction through the remainder of the night. On Saturday, expect strengthening SE flow by mid afternoon when gusts may exceed 20 kts. A period of lower CIGS with bases 040-060 looks favored for later this evening (starting ~02-03Z) through early Saturday morning, before transitioning back to VFR conditions for all terminals. && .FIRE WEATHER... Issued at 303 PM MDT Fri May 3 2024 Increasing fire danger is expected late this weekend into early next week behind the strong storm system. Gusty winds should develop on Sunday and continue daily through at least mid-week, with a gradual drying trend from Sunday through Tuesday. Near- critical to critical fire weather conditions appear likely across portions of the lower elevations at times, especially south of I-70. However, recent rainfall and ongoing green-up across the plains may limit overall fire danger. Still a couple of days out at this point, so no watches have been issued... but we'll be watching closely as we get into the weekend. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Mensch LONG TERM...Hiris AVIATION...Rodriguez FIRE WEATHER...Hiris ####018004967#### FXUS63 KEAX 032328 AFDEAX Area Forecast Discussion National Weather Service Kansas City/Pleasant Hill MO 628 PM CDT Fri May 3 2024 ...Updated 00z Aviation... .KEY MESSAGES... - A chance for scattered showers and thunderstorms are forecasted for overnight into early tomorrow morning. Isolated strong storms may be possible. - There is a potential for strong to severe storms on Monday. All hazards are possible. - Additional rounds of rain may cause river flooding to continue. && .DISCUSSION... Issued at 351 PM CDT Fri May 3 2024 There is currently a progressive longwave pattern over CONUS with strong ridging in the east and troughing in the northern Great Plains region. The upper level jet is rounding the base of the trough from Nebraska curving into Minnesota. There is currently a west-southwesterly flow over the region. At the surface, there is high pressure just to the north of the area resulting in easterly winds. SPC Mesoscale Analysis shows increased 850MB flow into southern Nebraska. Added effects of diurnal heating results in wind gusts as high as 15-20 mph through the afternoon. Tonight, a smaller, quickly-moving shortwave trough will merge with the trough to the north of our area. The warm front associated with the smaller shortwave is expected to impact the area later tonight. This will result in low temperatures being ~10 degrees warmer than last night as warm air advects with southerly winds. As the surface cold front approaches the area, scattered showers and thunderstorms are possible out ahead and along the frontal boundary. With MUCAPE values ranging from 1,000-1,500 J/kg and bulk shear around 30-35 knots, there may be a chance for a few strong thunderstorms with strong winds and hail. At this time, the main threat is expected to be further west. However, with the consistent rainfall we have been having, pooling and ponding along roadways may be possible. SPC has recognized this by putting our area in a marginal chance for severe weather for this time period. Frontal passage is expected tomorrow afternoon. With cooler, drier air pushing in behind the front, expect high temperatures to be a little cooler than yesterday with highs in the mid 60s to low 70s. Sunday, decent mid level ridging builds in behind the trough resulting in high pressure at the surface across northern Missouri. Meanwhile, a surface cyclone tracks across the Ozarks Sunday resulting in a chance for some showers for areas south of I-70. High temperatures are expected to be in the upper 60s to low 70s while low temperatures are forecasted to stay in the 50s. On Monday, the mid level ridging shifts slowly to the east as another trough enters central CONUS and becomes more negatively- tilted. By late Monday evening, winds will shift to the south as our region enters the warm sector of the associated surface warm front. As a result of this, return-flow from the Gulf will help to slowly destabilize the environment. The surface front is expected to pass through overnight into Tuesday. With the passage of this front showers and thunderstorms are expected. CAPE values around this time range from 2,000 J/kg to 3,000 J/kg which suggest plenty of instability for convective activity. With bulk shear values exceeding 40 knots, there will ample shear to aid in storm organization as well as create a favorable environment for large hail and damaging winds. Showers and thunderstorms are expected to linger into early Tuesday morning as the system moves east. Tuesday, the pattern continues its unsettled trend as multiple shortwaves pass through by the end of the week. The trough continues its track northerly and then begins to linger in southern Minnesota. As multiple shortwaves eject from the stagnant trough, chances for showers remain through next week. By next weekend the trough finally begins to shift south and becomes positively-tilted as it moves to the southeast of the area. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 624 PM CDT Fri May 3 2024 VFR conditions forecast for the remainder of the evening. Line of showers and thunderstorms expected to develop in Central Kansas overnight and should arrive at the terminals early Saturday morning. Thunderstorms weaken as they move across eastern Kansas. Therefore, have placed showers in the forecast with thunderstorm in the vicinity. If trends indicate thunderstorms to prevail as they move through the terminals, 06z TAF issuance will be able to address more specific timing. As showers come through and pass, a brief period of IFR ceilings are possible. && .EAX WATCHES/WARNINGS/ADVISORIES... MO...None. KS...None. && $$ DISCUSSION...Collier AVIATION...Krull ####018001142#### FXUS62 KTBW 032328 AFDTBW Area Forecast Discussion National Weather Service Tampa Bay Ruskin FL 728 PM EDT Fri May 3 2024 ...New UPDATE, AVIATION... .UPDATE... Issued at 719 PM EDT Fri May 3 2024 Less moisture available this evening will discourage any shower development. Much of the same expected tomorrow with above average temperatures with a few more pop up showers late in the afternoon. Otherwise, no changes made to the forecast, everything remains on track. && .AVIATION... (00Z TAFS) Issued at 719 PM EDT Fri May 3 2024 VFR conditions prevail, with some wind shifts expected. SE winds will veer onshore with seabreeze development in the afternoon. && .PRELIMINARY POINT TEMPS/POPS... TPA 72 90 73 89 / 0 20 20 30 FMY 70 90 70 90 / 10 40 20 40 GIF 67 91 69 90 / 0 30 20 40 SRQ 70 90 71 90 / 10 20 20 20 BKV 64 91 66 90 / 0 20 10 30 SPG 74 87 75 88 / 0 20 20 30 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE/AVIATION...Pearce ####018005055#### FXUS63 KFSD 032329 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 629 PM CDT Fri May 3 2024 .KEY MESSAGES... - Rain is expected to move through after dark and into Saturday morning. Rainfall amounts from 0.25" to 1" may be possible. Highest amounts in Northwest Iowa could lead to minor increases in already ongoing flooding. - Cooler temperatures on Saturday (low 60s), with middle and upper 60s on Sunday. Dry conditions expected both days. - Winds approaching advisory criteria may arrive Monday, prior to the arrival of late afternoon and overnight thunderstorms. - The greatest severe weather risks continue to remain focused south of the Missouri River and Highway 20 corridor, however continue monitoring of the forecast is recommended. && .DISCUSSION... Issued at 623 PM CDT Fri May 3 2024 Surface obs indicate the location of the cold front to be in a line roughly from Mission South Dakota northeast through Redfield South Dakota. This front will continue to advance southeastward through the afternoon and evening. Strong frontogenesis in concert with the front will trigger showers and maybe even some thunder. Current radar indicates light rain showers over central South Dakota. These showers will advance along with the front. There is little in the way of instability tonight, so we do not expect these showers to become severe. However, some of the rain showers could produce significant rainfall, especially over northwestern Iowa, where a half to an inch is possible. Elsewhere, totals are expected to be around a quarter to a half inch. Rain showers will be well east of our area by mid Saturday morning. Lows for tonight will be cool, in the upper 30s to 40s. Clouds thin as high pressure builds in Saturday, revealing sunny skies for the afternoon. Winds will be northwesterly bringing a healthy dose of CAA southward, limiting our highs to the upper 50s and 60s. The overnight lows will again be cool, in the upper 30s and 40s. As the high moves to the east, winds will swing around to the southeast Sunday. WAA in the 850 mb level warms temperatures there into the 6-10 deg C range. This indicates that highs at the surface will warm into the mid 60s to low 70s. Sunday night, a low pressure system begins to push through the Rockies, tightening the SPG in front of it. Winds will increase overnight and through the day Monday. I felt that the NBM winds were too strong after considering the model soundings. After collaboration with neighboring offices, went with a 50/50 blend of the NBM and CONSALL. Even after knocking winds back a bit, we are still looking at strong winds for Monday. Sustained at 30-35 mph with gusts 40-45 mph. It may be necessary as we get more information to include a headline for winds, but at this time confidence is too low. Monday morning the surface low ejects out of the Rockies into the north-central Plains, bringing the next round of showers and thunderstorms. Models this round have come into better agreement on the low exiting Colorado and taking a sharp northeasterly track through western Nebraska and South Dakota. As it does so, it will drag a warm front across eastern Nebraska and South Dakota. Instability in the warm sector increases to 500-1000 J/kg of CAPE. Enough to support some thunderstorms. The more favorable environment for severe weather remains over the central Plains, however, a few strong to severe thunderstorms are still possible over southeastern South Dakota and northwestern Iowa Monday night into early Tuesday. Rain totals are still a question mark, with ensembles indicate 80- 100% probability of exceeding 0.1 inches, and 30-60% probability of exceeding 0.5 inches. Rain is expected to be east of the area by Tuesday afternoon. Highs will be 70s for Monday and 60s for Tuesday. The low pressure system then hangs out over the northern plains for the rest of the week, gradually occluding and then moving off to the southeast. Multiple shortwaves form and pass through the area off of that main system, bringing multiple chances for showers through the week. Temperatures will be in the 60s. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 623 PM CDT Fri May 3 2024 VFR conditions with scattered sprinkles continue this evening. Gradually we'll see the arrival of rain after dark, moving from west to east throughout the Tri-State area into the pre-dawn hours. Ceilings may fall to MVFR levels with visibility dropping towards 3SM at times. MVFR ceilings may linger through Saturday morning as breezy northwest winds prevail. Skies may break into a scattered VFR CU field in the afternoon. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...AJP AVIATION...Dux ####018006779#### FXUS66 KOTX 032330 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 430 PM PDT Fri May 3 2024 .SYNOPSIS... Temperatures on Saturday will be mild with highs in the 60s and low 70s. Bands of rain will spread into central Washington on Saturday. Widespread rain is expected on Sunday as a slow moving low moves through the Pacific Northwest. As the low pulls out of the region, look for cool, showery, and windy conditions Monday and Tuesday. Warmer and drier weather will likely arrive late next week. && .DISCUSSION... Tonight and Saturday: Clouds will be on the increase tonight into Saturday as a slow moving low off the coast of Washington this afternoon pushes into Oregon and northern California on Saturday. Rain will be slow to spread east of the Cascades. Chances for measurable rain will be less than 50 percent east of Omak, Waterville and Moses Lake until late Saturday evening. Even though Saturday will be mostly cloudy, temperatures will be mild. Morning lows will range from the 40s in north Idaho and northeast Washington to the low 50s in Moses Lake and Wenatchee. Highs are expected to be in the 60s Saturday for the majority of the Inland Northwest. Sunday: There is decent model agreement that the most significant precipitation with this slow moving low will occur south of Washington and Idaho Saturday and Sunday with a foot or more of snow for the high elevations of the Oregon Cascades and mountains of northern California. However, this storm should deliver some much needed rainfall to eastern Washington and north Idaho. Models often struggle with wrap around precipitation, and we have seen some variability in the ensembles the last few days with the timing and location of the deformation band wrapping into the Inland Northwest. The latest National Blend of Models (NBM) generates the most significant band of rain Sunday and Sunday night across the eastern third of Washington and over the north Idaho Panhandle. The NBM deterministic output (most likely scenario) has a swath of a quarter to half inch centered along the WA/ID state line Sunday and Sunday night. The NBM 75th percentile increases these amounts to localized amounts of two-thirds of an inch while the 25th percentile knocks amounts in the rain band down to a tenth to quarter of an inch. Rains across the Palouse and West Plains will be welcomely received by dryland farmers after a dry April. However, outdoor activities on Sunday will be dampened by the rain and much below average temperatures. Places that experience an all-day rain may struggle to get out of the 40s Sunday afternoon including Spokane, Pullman, and the Idaho Panhandle. Places like Omak and the Methow Valley may remain north of the main rain band and have a good chance of topping out in the 60s. Monday and Tuesday: The beginning of the work week will be cooler than average, showery, and locally windy. As our deep weekend low migrates eastward, a tight westerly pressure gradient will set up across the Cascades on Monday. Then on Tuesday, a fast moving shortwave descending from the Gulf of Alaska will dig into the Pacific Northwest delivering another round of gusty west winds. Guidance form the ECMWF ensembles suggest that wind gusts of 30 to 35 mph will be a good bet Monday with 70 percent of members generating gusts of 35 mph or higher across the open country of southeast and east central Washington on Monday and 50 percent of members on Tuesday. Showers will be more widespread Monday with a 60 to 80 percent chance of measurable precipitation over the Idaho Panhandle and the eastern third of Washington. Shower chances should decrease on Tuesday as drier air accompanies the Gulf of Alaska system, however snow levels will drop unseasonably low Tuesday...as low as 3000 feet in the morning and again overnight into Wednesday morning. If you haven't gotten your fill of graupel this spring, Tuesday will give you another shot at seeing our "corn snow", "snow pellets", or (insert your favorite graupel name). Wednesday and Thursday: The medium range models are trending toward a more amplified ridge/trough pattern over North America by mid to late week. While there are some differences in where the ridge axis will set up by Thursday and Friday of next week, the majority of the ensemble members are forecasting above average temperatures and dry weather Thursday and Friday. The NBM advertises highs in the mid 60s to mid 70s Thursday and widespread 70s for Friday. /GKoch && .AVIATION... 00Z TAFS: A low pressure system will move slowly onshore off of the eastern Pacific tonight. This will spread mid to high level clouds across the region. Light rain is expected across the Cascades by the morning hours on Saturday with rain at KEAT by 14-16Z. Ceilings down to 3-4 kft with MVFR conditions possible. South and easterly winds will pick up with the front approaching through the day today into Saturday as well. KPUW-KGEG-KCOE will see the potential for gusts up to 25 kts into Saturday morning with the easterly pressure gradient tightening up. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence for VFR conditions through Saturday afternoon except for at KEAT where confidence is moderate. The HREF/NBM model guidance for KEAT indicates a 50% chance ceilings lower down to between 2-3 kft agl. and visibility down to 4-6 miles with rain by 15Z. /SVH ----------------------- Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance For additional probabilistic information for NWS Spokane airports, please refer to the Aviation Dashboard on our webpage: https://www.weather.gov/otx/avndashboard && .PRELIMINARY POINT TEMPS/POPS... Spokane 45 69 42 49 40 56 / 0 10 40 90 80 40 Coeur d'Alene 42 68 42 49 39 52 / 0 10 30 90 90 60 Pullman 46 65 39 45 38 52 / 0 10 80 100 80 60 Lewiston 47 73 46 54 44 59 / 0 10 90 100 80 60 Colville 40 68 42 57 38 60 / 10 20 20 90 80 70 Sandpoint 42 66 44 51 39 52 / 0 10 30 90 90 80 Kellogg 43 65 44 48 40 47 / 0 10 40 100 90 80 Moses Lake 53 71 44 58 42 63 / 10 40 60 80 30 10 Wenatchee 52 62 49 60 44 60 / 10 70 40 30 20 20 Omak 49 69 49 64 42 65 / 10 40 30 40 40 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$