####018008814#### FXUS66 KMFR 040338 AFDMFR Area Forecast Discussion National Weather Service Medford OR 838 PM PDT Fri May 3 2024 .DISCUSSION...Radar imagery this evening is showing a widespread band of precipitation moving east through the region, with the leading edge of the band at just about the border between Jackson/Douglas counties and Klamath. So far we've seen about 0.40-0.80" reported by stations in Coos, Curry, and northwest Douglas counties; 0.10-0.20" in Josephine and the remainder of Douglas; and a whole 0.01" in Medford and along the Cascades, where rain is juts getting going. Precipitation will continue in the aforementioned areas as well as continue to spread east through the region overnight into early Saturday. Most of the precipitation out there is hitting the ground as rain right now, with snow levels above 7,000 feet. This will swiftly change overnight into Saturday morning as very cold air (for this time of year) filters into the region and snow levels crash. For more details on this system and those upcoming, please see the previous discussion below. No major changes to the forecast were needed this evening besides slight adjustments to how fast precipitation was moving eastwards. -CSP && .AVIATION (00Z TAFs)... A robust system is making its way on shore which will lead to widespread MVFR and IFR conditions across the region. Rain intensity and low level moisture will lead to both visibility restrictions and low ceilings through this cycle. It wont be until tomorrow afternoon that we start to see some relief from these diminished conditions. Until then, expect clouds to increase and rainfall to spread over the region tonight and overnight. We may see a mix of rain and snow on the eastside which would impact the terminal at Klamath falls tomorrow. At times, precipitation rates could limit visibility to 2 miles or less, with IFR to perhaps LIFR at times. Overall, unfavorable flying conditions are expected to start soon for at least the next 18 hours. -Guerrero && .MARINE... && .PREV DISCUSSION... /Issued 304 PM PDT Fri May 3 2024/ SHORT TERM...Through Monday morning...An approaching low pressure system is already bringing rainfall to the Oregon coast. Rainfall will continue through the night over Coos, Curry, and western Douglas counties. Precipitation will steadily move eastward across the area through Saturday. Coastal areas will see about 2 to 3 inches of rainfall while west side valleys will get between half an inch and an inch of rain. Klamath and Modoc counties will get similar amounts of rainfall while Lake County will generally get half an inch of rain or less. The heaviest amounts will be late tonight through early Saturday morning. This system is bringing unseasonably cold air aloft, which will bring snow levels down from their current 8000 feet to 3000 feet by Saturday morning. While most snowfall will remain over higher terrain, the amount of moisture and the fast drop in snow levels will bring periods of heavy snow to the Cascades and to western Siskiyou County. Currently, 4 to 6 inches of snow are expected at elevations above 4000 feet for the Cascades and Siskiyou ranges, with a 20-30% chance of more than 6 inches over the Cascades by Sunday morning. Additionally, high resolution guidance shows a 40- 80% chance of snowfall rates of 1 inch per hour Saturday morning. Due to the dangerous travel conditions that these conditions are expected to make, a Winter Weather Advisory is in place for parts of western Siskiyou County from 2 AM to 11 AM on Saturday and for the Cascades from 2 AM to 11 PM on Saturday. This system will also bring elevated winds, especially across elevated terrain east of the Cascades. A Wind Advisory is in place for higher terrain in Lake County from Saturday at 5 AM through 5 PM. Gusty winds reaching over 40 mph are expected in this time, while wind gusts could still exceed 30 mph in other areas of Klamath, Lake, and Modoc counties. One final impact from this system will be a drop in nighttime temperatures from Saturday to Sunday. Temperatures will drop to the high teens to mid 20s for areas east of the Cascades. Below freezing temperatures are also possible west of the Cascades, although right now only the Shasta and Scott valleys look to be significantly below freezing. A Freeze Watch is in place for those valleys on Sunday morning, but below freezing temperatures are possible for the Rogue and Illinois valleys as well. Future guidance will help determine if additional products will be needed, bur right now that looks unlikely. The effects of the system continue through Sunday, but are most likely limited to post-frontal showers over the Oregon coast and the Cascades. Cool daytime temperatures will continue and nighttime temperatures look to warm from Saturday night's levels. -TAD LONG TERM DISCUSSION...Models continue to show a front moving across the area on Monday with high chances (60 to 100 percent) across most the area. Precipitation amounts with this front on Monday will be mainly light with some moderate amounts (0.25 inches or more) over the Cascades, coastal mountains and along the coast. Snow levels will range from 4000 to 5500 feet. Additionally, models and ensembles support a slight chance (20%) for thunderstorms Monday afternoon across portions of southwest Oregon, including Coos, Douglas, Klamath and Lake Counties. Brief downpours and gusty winds may occur with any thunderstorms that develop. Then, moist, onshore flow will allow for lingering showers on Tuesday, especially across southwest Oregon zones with lesser chances across Northern California. High pressure builds into the area Wednesday and remains in place through the end of the wee. This will bring drier and much warmer weather. By Friday, high temperatures will likely be in the 80s for valleys west of the Cascades and in the 70s for valleys east of the Cascades. AVIATION...03/18Z TAFs...Prevailing VFR this morning will drop back to MVFR with local IFR cigs/vsbys as a potent cold front moves in, with periods of moderate to occasionally heavy precipitation this afternoon. VFR will prevail elsewhere inland through late this afternoon/early this evening. The front will spread moderate precipitation across the rest of the west side tonight, reaching east of the Cascades Saturday morning. Expect widespread MVFR conditions and local IFR in rain with higher terrain obscured in rain/snow. A rapid drop in freezing levels will occur overnight (~09-15Z) from west to east and especially around 12Z Saturday morning near the Cascades. Rain will change to snow down to as low as 2500 feet with brief heavy snow in the mountains, reducing visibility to LIFR at times. Breezy south winds are expected with the front too, with peak gusts in the 40-50 mph range. Despite the increasing winds, low level wind shear is not a concern at this time. Conditions should improve a bit behind the front with precipitation becoming more showery, but still with a good amount of MVFR ceilings/visibility through tomorrow morning. -Spilde/BPN MARINE...Updated 200 PM Friday, May 3, 2024...A cold front will move through today into this evening with moderate to heavy rain, gusty south winds and steep seas. Following the front, seas will remain steep, dominated by fresh short period west swell through tonight. Showers continue with a slight chance of thunderstorms (20%) on Saturday. West seas trend less steep Saturday afternoon through Sunday. Another front arrives Sunday night into Monday with the potential for gusty south to southwest winds followed by building west-northwest seas into Tuesday. After that, we expect high pressure to build in mid-late next week with a thermal trough strengthening along the coast. This will bring a return of stronger north winds and steep seas, highest south of Cape Blanco. -Spilde/BPN && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Winter Weather Advisory from 2 AM to 11 PM PDT Saturday above 4000 feet for ORZ027-028. Wind Advisory from 5 AM to 5 PM PDT Saturday for ORZ030-031. CA...Winter Weather Advisory from 2 AM to 11 AM PDT Saturday above 4000 feet for CAZ080. Freeze Watch from late Saturday night through Sunday morning for CAZ080-081. PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT this evening for PZZ350-356-370-376. && $$ ####018004894#### FXUS63 KAPX 040339 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 1139 PM EDT Fri May 3 2024 .KEY MESSAGES... - Quiet and mild weather through Saturday. - Showers and a few thunderstorms expected Saturday night. - Wetter pattern expected next week beginning on Tuesday with showers and thunderstorms. && .SHORT TERM /THROUGH SATURDAY/... Pattern Synopsis: Shortwave troughing will lift across Ontario today as the parent mid/upper-level low pivots toward Hudson Bay tonight. The associated surface cyclone will also trek across Ontario and over Hudson Bay by late tonight/early Saturday morning. A cold front extending southeast of the system center will keep pushing east of the area this afternoon and evening, leaving relatively high pressure in place through Saturday. Forecast Details: Quiet and mild weather through Saturday -- Remaining showers will end this afternoon as the aforementioned front continues to slide out of northern Michigan, leaving sunny skies in place for the remainder of the day. Clear/sunny skies will stay in place through Saturday morning, promoting efficient radiational cooling overnight to drop temperatures well into the 40s -- and even upper 30s across typical interior cold spots. Southerly flow will strengthen through the morning, bringing warm/moist air northward to help temperatures climb back into the low to mid 70s for areas of northern lower Michigan away from the lakeshores. Cooler temperatures in the 60s are anticipated across the eastern U.P. and those close to the lakes. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Pattern Synopsis and Forecast: Longwave troughing currently spanned across North America with embedded height disturbances keep weather mild and active at times for the entirety of the long term forecast period. Midlevel low pressure with attached troughing currently over the central CONUS/Canadian boarder and over the Alaskan Bay will be the main two sources of energy for the Great Lakes region this weekend and next week. The first trough over the central CONUS will progress towards the southern shore of Hudson Bay and pushing a shortwave trough through the Great Lakes region by Saturday evening. A cold front will proceed to deliver convective driven showers with the chance of a few thunderstorms Saturday night into Sunday morning. Attention switches focus on Tuesday when the second trough makes it way to the Northern Rockies and stalls over the region for the remainder of next week. Primary Forecast Concerns/Key Messages: Showers and a few thunderstorms expected Saturday night: A weak cold front will deliver a line of showers to the CWA Saturday night with the chance of a few rumbles of thunder remaining possible. Weak convection tied to the line will have no severe threat associated with the system, but areas across northern Michigan can expect a soaking of rain as QPF amounts remain around a general tenth or two. Higher amounts of liquid remain possible as more convective showers could produce some higher totals but no overall impactful weather is expected. Wetter pattern expected next week beginning on Tuesday with showers and thunderstorms: Sunday and Monday remain dry as midlevel shortwave ridging pushes quiet weather into the Great Lakes region. Low dew points do raise concern for potential fire weather conditions, especially this Monday, but weaker winds keep the conditions questionable ahead of aformentioned midlevel low pressure returning showers and storms this Tuesday. Current guidance is depicting favorable conditions of strong thunderstorms as dewpoints push themselves into the upper 50s overnight Tuesday into Wednesday ahead of cold front. To early to determine severity of this line, but will continue to monitor this feature with later model runs. Midlevel low pressure/troughing will stall over the northern plains the remainder of the forecast period, continuing lingering showers at times across the Great Lakes region for the rest of the work week. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... IFR producing fog and low clouds to impact KAPN (and perhaps KCIU) through early this morning. Any low clouds/fog/mist should burn off quickly after sunrise. Otherwise, VFR conditions expected, with just some increasing high and mid level clouds during the day. Next round of lower cigs and increasing shower chances returns from the west this evening. No significant wind concerns through the period. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ SHORT TERM...DJC LONG TERM...SJC AVIATION...MSB