####018009898#### FXUS63 KMQT 231520 AFDMQT Area Forecast Discussion National Weather Service Marquette MI Issued by National Weather Service Gaylord MI 1120 AM EDT Tue Apr 23 2024 .KEY MESSAGES... -For the north half of the UP, today's weather features rain turning to snow and breezy conditions, though little to no accumulation is expected. -For the south half of the UP, clearing skies early will allow for thunderstorm potential to build for the afternoon along with breezy conditions, though chances of severe weather are below 5%. -Dry weather in the midweek under high pressure. -Active weather pattern returns this weekend and continues into next week and looks wet. && .UPDATE... 12z surface/composite analysis shows a 997mb low just off the Keweenaw Peninsula along an east-west baroclinic zone with some pretty chilly air to the north across northern Manitoba/Ontario (single digits above and below zero) along with strong pressure rises (4-6mb/3h across northwest Ontario). A second less defined front (at least across the northern end) extends southwest from the low across western Upper/northwest Wisconsin/Iowa. Water vapor imagery shows several vorticity centers rotating through a positive tilt short wave trough over the upper Midwest/upper Great Lakes; one such wave rolled across Upper Michigan this morning with a couple more over northern Wisconsin/central Minnesota. Dry slot across Upper Michigan/northern Wisconsin has largely cleared things out this morning though more clouds and high based showers are not far to the north and west. 500mb cold pool has steepened mid level lapse rates (700-500mb > 8C/km). Cold front over Lake Superior will get pushed south across Upper Michigan this afternoon (already across the Keweenaw at late morning)...with a wind shift to the north/northwest. Clouds and scattered high based rain showers moving back into far western Upper...which will continue to expand east aided by weak stability which should allow for the potential for deep enough convection to allow charge separation/thunder (have already seen this earlier today across northern Wisconsin/northern Lower). Will also be watching precipitation (snow) wrapping around compact mid level low into northern Lake Superior...while precipitation coverage may thin there will probably be enough to allow for some snow on the back end of this during the late afternoon/early evening. Temperatures expected to drop quickly with cold front passage...from morning/ early afternoon temperatures in the 50s/mid 60s down into the 30s/lower 40s by early evening. So some big swings in weather today from warm with showers/thunderstorms early to colder/windy later with some snow to wrap things up. && .SHORT TERM /THROUGH THIS AFTERNOON/... Issued at 445 AM EDT Tue Apr 23 2024 GOES-16 WV imagery shows a secondary push of moisture pushing through the central UP from west to east this morning. This is associated with a secondary shortwave aloft following the initial frontal passage earlier in the overnight period. RAP analysis shows a 996mb surface low at the very northernmost point on Lake Superior with the upper low spinning along the MN/Canada border. The HREF shows that after this secondary surge of moisture, dry-slotting will allow for a break in the precipitation until the mid-morning hours. The low dropping southeast will be the forcing mechanism for showers today, with the main impacts to the forecast being precipitation type in the north and thunderstorm potential in the south. In the north, the HREF shows that PoPs reenter the forecast around 15Z as the low moves over eastern Lake Superior and wraparound moisture is lifted by the low and enhanced by the terrain of the western and northern UP. As the winds turn northerly through the morning and cool Canadian air surges south, rain showers will changeover to snow. The HREF suggests that there's a 50-90% chances that all of the UP north of US-41 and west of Marquette will see 0.5 inches worth of 10:1 snowfall. However, actual accumulations are expected to be less than that given the springlike temperatures lately having warmed the ground, so actual sticking snow should be minimal. This warm ground will also protect from any rain-to- snow freezing surface threats. Further south, the clearing skies in the dry slot will allow for surface temperatures to climb well into the 60s, and the NBM suggests a 10% chance of reaching 70 in Menominee today. This heating will allow for surface instability to build, with HREF 25th- 75th percentile SBCAPE this afternoon building to 300-900 J/kg. As the low drops south and surface convergence increases, HREF simulated reflectivity paintball plots exceeding 35 dBZ become quite colorful beginning around 17Z through 00Z for much of the US-2 corridor. Mean SRH values around 100 m2/s2 should limit the organization of these storms somewhat. Given the deep inverted V soundings and freezing levels above 700mb, sub-severe hail and isolated strong winds are possible today, though probabilities of severe weather threats in any given 25-mile radius zone in the UP are below 5% today. && .LONG TERM /TONIGHT THROUGH MONDAY/... Issued at 250 AM EDT Tue Apr 23 2024 Upper air pattern consists of a 500 mb trough in the lower Great Lakes 00z Wed. This trough moves away and is replaced by a shortwave ridge in the upper Great Lakes 12z Fri. Snow showers should end early this evening and then dry weather most of tonight into Thursday night. Looked at fire weather concerns for Wed and Thu and the strong winds are not there along with cold temperatures. Relative humidities are the only thing there, but not sure how wet the fuels are. In the extended, the GFS and ECMWF show a broad 500 mb trough in the western U.S. with a ridge in the east. In this trough there is a shortwave that is negatively tilted in the central plains 12z Fri. This trough then heads northeast into the upper Mississippi Valley 12 Sat. Next wave comes out of the trough into the central plains 12z Sun and then heads into the upper Great Lakes 12z Mon and into the lower Great Lakes 12z Tue. Active pattern in this forecast period and temperatures go from above normal to near normal for this period. Also looks wet with storm track over the area or just to the south. && .AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/... Issued at 737 AM EDT Tue Apr 23 2024 VFR prevails at all TAF sites this morning. A low pressure system passing south through the eastern UP will bring unsettled weather and lower flight categories later today. SHRA will be around the vicinity of all the TAF sites beginning later in the morning, but with the wind becoming northerly and gusty, cool air will change SHRA to SHSN at around 18Z at CMX and 21Z for IWD and SAW. SAW will also have chances at TS (15-30%) in the early afternoon hours before the changeover to SHSN. With the showers and moistening atmosphere will come lower ceilings, with low-end MVFR at all sites in the late morning to early afternoon hours and IFR at SAW and CMX in the early afternoon. Worth noting is that model trends have decreased confidence in MVFR ceilings before 20Z at IWD, so there is increasing confidence that VFR will hang on longer there. Vis will most likely be P6SM, but if a SH in the VC of a TAF site goes over the airfield, MVFR ceilings are possible. This is most likely at CMX with about 1-in-3 chances of MVFR or IFR vis around 18Z-21Z, with around 10% chances at SAW and IWD. SAW is particularly notable because while 90% of guidance has VFR vis, the 10% that brings vis down brings it down to VLIFR. It is a low confidence solution for sure, but could see high impacts if it comes to fruition. && .MARINE... Issued at 250 AM EDT Tue Apr 23 2024 Winds increase by late morning as a strong cold front drops down from the north, bringing with it north-northeasterly gales up to 35 knots across the central and eastern lake today. As the cold air advection ceases by this evening, expect the winds to die down, eventually becoming 20 knots or less by Wednesday morning as a high pressure sets up over the lake. This high pressure keeps the winds light across the lake through Thursday. Stronger winds don't look to show up again until Thursday night, when an approaching front brings southeast winds of 20 to 25 knots back across the lake. As it's parent low approaches from the Southern Plains Friday, expect the winds to increase to 20 to 30 knots from the southeast. As the low moves into Lake Superior Saturday, expect winds to turn northerly to 25 to 30 knots behind the low's center from west to east across the lake. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Small Craft Advisory until 8 AM EDT /7 AM CDT/ Wednesday for LSZ240>242. Gale Warning until 8 PM EDT this evening for LSZ243>245- 263>266. Small Craft Advisory from 8 PM this evening to 10 AM EDT Wednesday for LSZ243>245. Small Craft Advisory until 6 AM EDT Wednesday for LSZ246-247. Small Craft Advisory until 1 PM EDT Wednesday for LSZ248>251. Gale Warning until 2 AM EDT Wednesday for LSZ267. Lake Michigan... Small Craft Advisory until 11 AM EDT Wednesday for LMZ221. Small Craft Advisory until 8 AM EDT Wednesday for LMZ248-250. && $$ UPDATE...JPB SHORT TERM...GS LONG TERM...07 AVIATION...GS MARINE...07 ####018012654#### FXUS61 KBUF 231524 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 1124 AM EDT Tue Apr 23 2024 .SYNOPSIS... High pressure that supplied us with beautiful weather on Monday will drift off the East Coast this afternoon. A strengthening southerly flow in its wake will now transport milder air and increased moisture into our region. Clouds will continue to thicken and lower through the afternoon ahead of a slow moving frontal system approaching from the upper Great Lakes that promises to generate a quarter to a half inch of rain for us tonight into Wednesday morning with chilly temperatures on Wednesday. An expansive area of Canadian high pressure will then assure us of fair dry weather Thursday and Friday, before chances for showers return this weekend. Temperatures remain chilly on Thursday, followed by day-to-day warming with readings soaring to well above normal levels by the second half of the weekend. && .NEAR TERM /THROUGH WEDNESDAY/... Our short stint of fair dry weather is about to come to an end, as the area of high pressure that supported a nice day on Monday is now drifting off the East Coast. While most of the region will be able to enjoy some sunshine through increasing high clouds through midday, a strengthening southerly flow ahead of a wavy frontal boundary will encourage clouds to lower and thicken during the afternoon. Unfortunately, there will be enough lift provided by a coupled H25 jet and surface convergence in the vicinity of a pre-frontal trough to encourage some showers to develop over the western counties by mid to late afternoon. Along with the increased cloud cover and eventual resulting precipitation today, a 45kt low level jet within the warm advective pattern will at least partially mix to the surface. This will allow surface winds to gust to at least 30 mph across the region, with gusts as high as 45 to 50 mph possible for parts of the Niagara Frontier. A Wind Advisory remains in effect for Niagara and northern Erie counties where the threat is greatest. Its not all bad news for todays weather though, as moderately strong warm advection will prompt temperatures to climb well into the 60s for the afternoon. These readings will be a solid 10 to 15 degrees higher than those from Monday. Tonight, a very robust mid level shortwave and attendant storm system will gradually cross the Lower Great Lakes. While the main surface low will remain relatively weak and somewhat disorganized, moderately strong lift provided by the aforementioned coupled jet, and moreso by 100dm hgt falls and surface convergence ahead of a wavy surface front will lead to widespread rain over the forecast area. The precipitation which should be more showery in nature early on, will transition into a 3-5 hr period of steady rain to the tune of a quarter to one half inch (basin avg). Localized higher amounts will be possible as PWAT values approaching one inch should support embedded areas of moderately heavy rain at times. While colder air will seep southwards into our region on the immediate backside of the wavy front towards daybreak, the cold advection is not as robust as earlier projected. Will thus slow any transition to wet snow showers until after sunrise. The wavy frontal boundary will push off to our east Wednesday morning. While notably drier air will quickly overspread our forecast area in the process, some leftover light rain should be expected up until about midday. This will especially be the case for the Eastern Lake Ontario region where a quarter inch of rain will be possible. Some of this leftover precipitation will become mixed with wet snow as a shallow and short lived DGZ should become established. As we work our way through Wednesday afternoon, skies should yield at least partial sunshine with the sunniest skies opening near and east of Lake Ontario. Temperatures should reach their peak at some point in the morning before remaining steady or slowly falling during the afternoon. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... Sprawling Canadian high pressure will settle directly across our area Wednesday night and Thursday...before slowly drifting east and off the New England coast later Thursday night and Friday. We can therefore expect tranquil and dry weather to dominate our region throughout this period...along with mainly clear/mostly sunny skies. The coldest temperatures of the period will come Wednesday night as the core of the high settles directly overhead and provides ideal conditions for strong radiational cooling. This will allow temps to tumble into the mid to upper 20s across the lake plains...the lower 20s across the interior Southern Tier...and even to around 20 east of Lake Ontario (the current forecast min temp of 20F for Watertown is just a couple degrees shy of the record low for 4/25...which is 18 degrees set in 1972). Strong late April diurnal influences will then begin to modify our chilly airmass on Thursday...allowing highs to mostly recover into the upper 40s to mid 50s...though a developing onshore flow off Lake Ontario will help to keep areas along the south shore of that lake confined to the mid 40s. Another rather chilly (though not quite as cold) night will then follow Thursday night as the high begins to slide off to our east...with mins ranging from the mid 20s across the North Country to the lower 30s across the lake plains of far western New York...where a the beginnings of a southeasterly return flow will develop as the night progresses. As the high drifts further east of our region on Friday...the SSE return flow will strengthen and spread milder air back across our region...allowing highs to bounce back to around 60 east of Lake Ontario and to the lower to mid 60s elsewhere...with the warmest readings found in areas of favored downslope flow along the Lake Erie shoreline. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Friday night and Saturday an initial weakening cutter-type system will lift northeastward across the northern Plains and Upper Great Lakes. A warm frontal boundary snaking southeastward from this low will approach from the west Friday night before partially crossing our region during Saturday...while tending to weaken over time as it pushes further out ahead of its also-weakening parent low. Current model consensus continues to suggest an associated band of showers approaching/crossing far western New York late Friday night/Saturday morning...with this activity then at least somewhat weakening/ diminishing in coverage as it pushes further east Saturday afternoon. With this in mind will continue to carry a period of likely PoPs across far western New York Saturday morning...before dropping these back to the chance range as the afternoon progresses. Otherwise...broad warm air advection across our region will result in a continued upward arc in temperatures...with lows in the lower 40s east to around 50 west Friday night followed by widespread highs in the 60s Saturday. Should the showers diminish across far WNY as currently thought during Saturday afternoon...850 mb temps of +9 to +10C and a stiffening southerly downslope flow could easily support highs breaking into the lower 70s along the Lake Erie shoreline and across the Niagara Frontier...even in spite of what should still be fairly cloudy skies. Saturday night and Sunday the initial surface low will continue to weaken as it pushes northeastward across Quebec Province...with its trailing cold frontal boundary now looking increasingly likely to stall out well to our north as a second and stronger cutter-type low develops across the Upper Mississippi Valley...and upper-level ridging noses northward across New York State. With daytime heating on Sunday...cannot rule out some additional scattered showers/a few thunderstorms as our region becomes more firmly embedded within the warm airmass on the east side of these two systems...however with the main surface boundary remaining to our north areal coverage should be lower than on Saturday...with drier weather tending to be more predominant. The much bigger story will be temperatures...as 850 temps will surge to between +11C and +13C and support late spring to early summerlike warmth across our region. Expect temps to range through the 50s Saturday night...then climb well into the 70s south of Lake Ontario on Sunday...with a few of our normal warm spots in the Genesee Valley likely even breaking the 80 degree mark. This being said it will be a bit cooler east of Lake Ontario...as well as immediately downwind of Lake Erie owing to a southwesterly breeze off that lake. Sunday night and Monday the second and stronger cutter low will make its way across the Upper Great Lakes and into Ontario Province... with this next system eventually pivoting its trailing cold front toward our area during Monday. Consequently generally dry weather should prevail Sunday night...with the approaching front then bringing an uptick in shower and thunderstorm potential on Monday. Otherwise we can expect late spring to early summertime warmth to continue...with lows of 55-60 Sunday night followed by fairly widespread highs in the mid 70s to lower 80s on Monday. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... VFR conditions will remain in place through this afternoon, although surface winds will gradually increase as the day matures. surface wind gusts will reach at least 30 knots for all of the TAF sites today, with gusts as high as 40 knots at KBUF and KIAG. During the course of this afternoon, VFR level clouds will gradually lower and thicken with showers expected west of the Genesee Valley by late in the afternoon or early evening. Widespread rain will then move across all of western and northcentral New York tonight, as a slow moving frontal system will make its way through the region. CIGS will lower to MVFR levels during the evening, then to IFR levels for many areas during the wee hours of Wednesday morning. Outlook... Wednesday...MVFR to IFR CIGS with rain ending early. Thursday and Friday...VFR. Saturday...VFR/MVFR. A chance of showers. && .MARINE... Freshening southerly winds will gradually become more southwesterly this afternoon. This would typically favor Small Craft Advisory conditions, but the early season cold dome effect is likely coming into play as model guidance is holding waves down for most areas, however there will still be some decent chop on the waters. The exception today is for the western third of Lake Ontario (W of Hamlin Beach), where a SCA for that area remains in effect. Will continue to monitor Lake Erie as winds slowly veer more southwesterly through the afternoon. A wavy cold front will then slowly pass through the region tonight. While winds and waves will briefly subside in the process (especially on Lake Ontario), a notable but short-lived increase in northerly winds can be expected on Wednesday. While the fetch will not be overly favorable for significant wave increases, the combination should be more than enough to generate rough conditions. Future Small Craft Advisories will likely be needed for this period, especially on Lake Ontario. && .FIRE WEATHER... Dry conditions with gusty winds are expected again this afternoon. Min RHs will fall below 30%. Wind gusts during the midday and afternoon hours will reach 30 to 35 mph. With fine fuels continuing to dry out today, an SPS remains in effect for all but far western NY. RH values will quickly recover late this afternoon and evening though, as showers will develop ahead of a slow moving cold front. The showers will transition into a widespread rain later this evening and overnight. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...Wind Advisory until 6 PM EDT this evening for NYZ001-010. MARINE...Small Craft Advisory until 11 PM EDT this evening for LOZ042. && $$ SYNOPSIS...JM/RSH NEAR TERM...JM/RSH SHORT TERM...JJR LONG TERM...JJR AVIATION...JM/RSH MARINE...JM/RSH FIRE WEATHER...JM/RSH