####018009213#### FXUS63 KGID 152124 AFDGID Area Forecast Discussion National Weather Service Hastings NE 424 PM CDT Thu May 15 2025 .KEY MESSAGES... - Friday looks to bring another round of strong west-northwest winds to the forecast area. Gusts of 40-50 MPH are not out of the question, with the strongest speeds expected to be mainly along/north of I-80. Most locations will stay dry, but similar to this afternoon, cannot rule out some isolated/scattered showers across northern locations. - The overall nicest day looks to be Saturday. There is a break in the gusty winds (which look to pick back up Sunday), with highs in the 70s and dewpoints in the 30s-40s. - A more active upper level pattern moves onto the Plains for Sunday into the start of the new work week, and strong-severe storms look likely...with one main question being exactly where. Portions of the forecast area are outlooked by SPC for severe weather potential...Sunday across SSW locations, Monday across ESE locations. Still plenty of uncertainty and details to iron out in the coming days. && .DISCUSSION... Issued at 419 PM CDT Thu May 15 2025 Currently... Easy to pick out the main feature of interest for the region this afternoon...with upper air and satellite data showing an area low pressure continuing to slide NNE through eastern SD. The main impact from this system as far as precip/severe weather goes remains well east of the forecast area...but with the system in the vicinity, combined with daytime heating leading to steeper lapse rates/increased mixing potential and at least a few hundred j/kg of instability...have seen some isolated/scattered showers and a few weak storms shifting east across portions of the area mainly along/north of I-80. This activity will continue through the rest of the afternoon...eventually waning with the loss of daytime heating. At the surface, low pressure is set up near the eastern SD/ND border...and though the pressure gradient across the forecast area isn't as tight as earlier today, thanks to that increased mixing potential, speeds remain gusty area-wide. These west- northwest winds were gusting widely in the 35-45 MPH range (a few closer to 50 MPH), especially through roughly midday...most gusts here at mid-afternoon are more in the 25-35 MPH range. As far as temperatures go...if anything, spots across northern portions where there are more clouds/spotty precip may fall a bit short of expectations...otherwise most of the area looks to reach the mid 70s- near 80. Tonight through Friday.... For the short-term period...overall it's a dry period, with models in good agreement showing that upper level low pressure system lingering over the north central CONUS, keeping flow over the area west-northwesterly. The lone exception to the dry forecast is during the afternoon hours Friday...which looks to be similar to what is currently going on, peak heating/steeper lapse rates allowing for the development of isolated/sct activity. Should affect a fairly small area, forecast has 20 percent chances over locations along/north of HWY 92. Outside of those small chances...the main story for this period lies with another round of strong winds for the daytime hours Friday. Later this evening-tonight, models show a lobe of shortwave energy rotating around the west and southern periphery of the main upper level low pressure system...driving a reinforcing cool front across the region. With the loss of daytime heating/steeper lapse rates, the current gusty winds are expected to diminish to closer to 10-15 MPH...ramping back up from west-east closer to sunrise as that front passes through. Similar to today, with the main sfc low lingering to our NNE, expecting WNWrly winds through the day...with the main change in this period being to increase wind speeds. Models showing the increased mixing once again, this time with winds to tap into aloft potentially being a touch stronger...especially in northern areas. Increasing cloud cover sinking south could hinder things...but gusts in those northern areas near 45-50 MPH are certaintly not out of the question. Forecast highs for Friday are in the mid 60s north to upper 70s south. Any precip that does develop during the afternoon will wane in the evening, with dry conditions through the rest of the overnight hours. Cloud cover is expected to diminish...along with winds...and overnight lows for most of the area look to drop into the low-mid 40s. This weekend on into the new work week... If you're looking for another day with a good temp/wind combination with no precipitation chances...Saturday looks to be your day. That upper level low finally gets more of a push east...allowing for broad ridging to slide onto the Plains, keeping precipitation chances out of the area. Expecting mostly sunny-partly cloudy skies...with lighter winds closer to the 10-15 MPH range. Winds start the day northerly, turning easterly with time as a sfc ridge axis slides off to our east and low pressure starts deepening over the High Plains. Forecast highs are remain in the 70s...while dewpoints sit in the 30s-40s. As we get into Sunday and the first half of the new work week...thunderstorm chances return to the forecast...and while not calling for a CWA-wide soaking of a few inches, these chances Sunday-Tuesday currently look better than most we've had lately. They aren't a slam dunk though...as always when talking about a timeframe still 4+ days out...lot of details to iron out in the models, so overall confidence in certainly not high at this point. Through the first half of the weekend, models showing upper level troughing digging south across the western CONUS, and by 12Z Sunday, models are showing low pressure over the Pac NW, with troughing/shortwave energy extending southward into the Desert SW. Through the day on Sunday, current models show that Pac NW low sinking SE, with that energy in the Desert SW swinging northeast out onto the Central Plains. It's arrival with drive the first potential bout of thunderstorms (some strong-severe possible)...with a big question lying with exactly the main sfc warm front/dryline set up. Sunday night on into Monday, models showing the potential for a bit of rotating 'dumbbell' action...as that first disturbance deepens somewhere over the central CONUS (is it more central or northern Plains?), what was that closed low over the Pac NW/sinking south, looks to fill as it swings around the southern side of that newly developed low...and it will be another driver behind thunderstorm activity, big question is exactly where. Eventually becoming more phased together...models show the system sticking around through the day on Tuesday, with higher PoPs finally lowering Tuesday evening/night. Especially for those Sunday and Monday chances...strong-severe storms look likely, but whether or not/how much the forecast area is impacted will be dependent not only on the timing/location of these upper level disturbances...but where the surface features/better moisture/instability end up setting up. For Sunday...the SSWrn portions of the area are included in the SPC Day 4 15 percent outlook area...Monday that outlooked area shifts to roughly the ESErn half of the area. Outside of preciptiation chances...forecast highs for Sun-Mon are currently in the 70s-80s, dropping into the 60s-70s for Tue-Wed as the main system finally moves out of the area. With strengthening surface low pressure/frontal boundaries expected, forecast wind speeds start picking up Sunday out of the SE ahead of the system...with more uncertainty as we get into Monday. Will be interesting to see how models trend with all of this in the coming days. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1233 PM CDT Thu May 15 2025 For KGRI/KEAR Airports: VFR conditions are currently forecast for this TAF period. This afternoon, already have CU field across much of the forecast area, area obs and model guidance support keeping ceilings VFR. This evening/tonight, any clouds passing through are expected to remain in the mid-upper levels...early-mid morning on Friday, not out of the question additional lower level clouds could start working their way in from the north...at this point kept them VFR. Gusty WNW winds will continue this afternoon, gusts near 40 MPH remain possible. There will be a period this evening-overnight where winds diminish down to closer to 15 MPH sustained...before a reinforcing front ushers in additional gusty WNW winds through the end of the period. The strongest gusts will favor the post-sunrise hours...gusts around 40 MPH will again be possible. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...ADP AVIATION...ADP ####018005079#### FXUS66 KPQR 152128 AFDPQR Area Forecast Discussion National Weather Service Portland OR 228 PM PDT Thu May 15 2025 .SYNOPSIS...A progressive weather pattern will bring periods of light rain through the weekend, and possibly into early next week. Expect temperatures to remain slightly below average during this period. Light, steady rain expected as a weak front moves across the area today. Rain showers increase late Friday night through Saturday, along with a 10-20% chance of thunderstorms Sat afternoon. Lingering showers into Sunday, though most areas likely drier. Temperatures trending warmer toward the end of next week. && .DISCUSSION...Tonight through Thursday...Radar imagery shows light rain spreading across the area this afternoon as a weak front pushes onshore. Expect the cool, cloudy and damp conditions to persist through this evening. Onshore flow will maintain light scattered rain showers overnight into Friday, with the highest chances of rain persisting along the northern coast and coast range through Friday. Total rainfall amounts are generally expected around a tenth of an inch or less, except 0.20-0.40 inch north of Astoria, including the Willapa Hills. High temperatures warm into the mid-60s inland, upper 50s along the coast, on Friday, potentially warmer across southern portions of the area (e.g. Lane County) where more sunshine is possible as clouds scatter out. The active pattern continues late Friday into Saturday as an upper level jet over the north Pacific moves towards the Oregon coast. An initial shortwave trough slides across western Oregon early Saturday morning, initiating widespread rain showers. Northwest flow aloft is maintained as the stronger system drops southward along the British Columbia coast, digging into the Pacific Northwest. This will also bring a slight chance (10-20%) of thunderstorms to the area for Saturday afternoon/evening. Persistent showers will likely produce a bit more substantial rainfall amounts, including a 30-50% chance of exceeding 0.25 inch through Saturday night across much of the forecast area. Showers will likely persist along the higher terrain, including the Cascade foothills, where amounts closer to 0.50-1.00 inch of total (48-hr) rainfall are possible. Most areas should expect conditions trending drier on Sunday, with more sun breaks through the clouds by the afternoon. Temperatures still remain on the cooler side with highs reaching the lower to mid- 60s inland. Models and their ensembles are coming into better agreement that a weak front brings another round of light rain across the region on Monday. Cluster analysis also showing more zonal flow likely on Tuesday, keeping the door open for some light showers. But still, uncertainty remains into the middle of next week as about 60% of the clusters show some type of weak ridging. Still, the NBM suggest temperatures are likely to trend closer to normal. /DH && .AVIATION...Currently VFR conditions throughout the airspace, with a low VFR overcast deck around 4000-5000 ft AGL, and westerly winds around 5-10 kts for all terminals. The next front is currently in the process of moving into the area, with rain expected to begin by 00z at latest. At that time coastal terminals will drop to MVFR with 60-80% confidence, while inland terminals see a 30-50% chance of MVFR ceilings beginning closer to 05-08z Fri. Winds remain under 10 kts while the front is impacting the area, but will slowly turn southerly over the course of Thursday night. PDX AND APPROACHES...VFR conditions through Thursday daytime hours, with a low overcast around 5000 ft AGL. Around 06z Fri, the next system begins moving in, bringing some rain showers and a 30-50% chance of MVFR cigs. Intermittent VFR/MVFR cigs expected through the end of the period. Winds will turn from westerly to southerly over the course of Thursday night, though remaining under 10 kts throughout. /JLiu && .MARINE...Seas of 5-7 ft at 10 seconds will continue to slowly subside to 4-6 ft by early Friday morning. Northwest winds of less than 10 kt will back out of the southwest to south through tonight, increasing to 10-15 kt on Friday as a reinvigorated northwest swell arrives ahead of a frontal system. South to southwest flow ahead of the front will veer back out of the northwest in its wake, with a 25-45% chance of gale-force gusts beyond 30 NM on Saturday, decreasing to 5-20% on Sunday. 70-90% agreement in at least Small Craft Craft winds during that time. Afterwards the next disturbances arrives Monday, marking a return to southerly winds around 10-15 kts. -Picard/JLiu && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...None. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland