Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/06/21


Area Forecast Discussion
National Weather Service Gray ME
1035 PM EDT Sun Sep 5 2021 .SYNOPSIS... A weak passing wave from the west will result in scattered showers tonight. Another trough will arrive late on Monday with showers and thunderstorms possible, especially across the north. High pressure will result in pleasant conditions on Tuesday before another frontal boundary approaches by the middle of the week with additional showers possible on both Wednesday and Thursday. Hurricane Larry will pass well offshore this week but building long-period swells are expected, which may result in increased rip currents. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 1030 PM Update...Much of the forecast area in the warm sector between a warm front near our border with Caribou`s CWA and a weak cold front located across eastern NY. Drizzle and light rain continue on the coast and central ME but this activity will gradually move northeastward overnight. Showers located across VT will move into western zones over the next two hours, perhaps with a rumble of thunder. However most of the forecast area should be dry by late tonight. Areas of fog are then likely. Strong short wave trough approaches our northern zones Monday, with a chance of strong thunderstorms, mainly across northern and central zones during the afternoon and early evening hours. 650 PM Update...Just a few minor adjustments to PoPs this evening based on latest radar imagery. Increased then across southeastern NH and southern ME to categorical based on latest radar mosaic loop. Otherwise, the rest of the forecast is in good shape. Previously... Clouds will continue to thicken and lower tonight amid warm, moist return flow w/ departing high. Showers have been very limited in coverage today, becoming a bit more widespread tonight with greater forcing moving in. With the WAA and clouds, tonight will be 10-15 degrees warmer than last night. Fog will likely develop in the usual CT Valley locations after midnight. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... The main item Monday will be the chance for thunderstorms, some strong, during the afternoon hours. Amid the longwave pattern aloft, a sharp shortwave will punch the trough negative. This will bring good forcing amid a region experience cooling aloft from the front overnight. The contrast between warm lower levels and cooling upper levels will create ample lapse rates in the mid and low levels. There is some question on how unstable the lower levels get through the morning, but any breaks in the clouds should bump temps into the mid-70s. HRRR and NAMnest runs have been consistent in painting single cell showers and storms developing into a broken line segment across the northern tier of counties (ME and NH). These showers and storms will have 50-60kts of 0-6km shear to work with, as well as the mid/low lapse rates 6-7 c/km. This certainly points to a small hail or gusty wind threat for storms that form along the vort passing through. MLCAPE remains marginal, but with other parameters in place, can`t rule out these storm attributes. Showers and storms move off to the east overnight, with just a few upslope showers possible in the higher terrain left in brisk WNW winds. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Overview: A continued active pattern is expected through much of the upcoming week as a series of relatively weak disturbances cross through allowing for several rounds of showery weather under broad upper-level troughing. While there will be several opportunities for a scattered showers, no major systems are currently expected and there will be plenty of pleasant weather mixed in between. Temperatures will remain near to slightly below normal for early September. Impacts: Hurricane Larry is expected to continue to move towards Bermuda through the upcoming week before turning more northward by Thursday. Although this system is expected to remain well offshore, long-period swells will likely begin to approach the Gulf of Maine by the middle to end of the week. High astronomical tides combined with building seas may result in some dune overwash and beach erosion. Forecast Details: High pressure will build to the southwest of New England on Tuesday allowing for increasing sunshine throughout the day and pleasantly warm high temperatures into the lower to middle 70s for locations outside of the mountains. Skies will remain mostly clear on Tuesday night and this combined with weakening winds should allow for some decent radiational cooling. As a result, expecting lows to range from the 40s across the north to 50s elsewhere. On Wednesday morning a deepening area of low pressure will be centered over the Northern Great Lakes, which will send a surface warm front northward through New England. Flow will increase out of the south during the day, which will allow dewpoints to climb into the 60s as high temperatures reach the upper 70s to lower 80s across southwestern ME and southern NH. Heights will fall during the day with increasing chances for showers and thunderstorms from west to east during the afternoon and evening hours. Wednesday night will be a mild one as the additional cloud cover, lingering showers, and high dewpoints keep most locations into the 60s. A cold front will gradually cross through New England late Thursday with additional scattered showers expected throughout the day. Dewpoints will gradually fall from north to south late in the day as winds turn more northwesterly. We will then dry out on Thursday night with gradually clearing skies, allowing for low temperatures to range from the 40s in the north to the 50s elsewhere. On Friday we will remain under weak 500 mb troughing with cyclonic flow, which will result in a non-zero threat for a few scattered showers to develop. The best chance for showers currently looks to be across the north where some upslope flow will be present. The Atlantic ridge and departing cold front will help to keep Hurricane Larry well offshore through the end of the week, although it will likely be close enough to result in increased seas across the Gulf of Maine. This combined with relatively high astronomical tides of around 10.6` Wednesday through Friday in Portland, may result in some beach erosion and dune overwash issues in addition to dangerous rip currents and high surf. This will need to be watched some as the timing of the frontal passage will help to determine how close Larry gets to our coastline before turning more easterly into the open North Atlantic. Broad high pressure will then build back into the area for the upcoming weekend with mostly tranquil weather and continued cool temperatures expected. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... Short Term...Ceilings will lower tonight to MVFR and then IFR across most TAF sites. -SHRA and BR can be expected through 12z Mon, with conditions improving to VFR. Some thunder and showers will be possible at inland TAF sites Mon afternoon, with a W wind shift in the evening and overnight hours. Long Term...VFR conditions expected on Tuesday as high pressure to our southwest keeps skies mostly sunny under light southerly flow. Scattered showers and thunderstorms are then expected on Wednesday and Thursday as a frontal system crosses through, which may result in brief flight restrictions. More prolonged MVFR ceilings will also be possible on Wednesday across some coastal terminals such as KRKD as southerly flow brings in moisture from the Gulf of Maine. VFR conditions will return on Friday as high pressure builds back into the area. && .MARINE... Short Term...A few gusts up to 25 kt will be possible this evening as a front approaching with increasing southerly winds. The front passes Monday morning, with another disturbance passing inland during the afternoon. Otherwise, conditions are expected to remain below SCA criteria, with waves generally 2 to 4 ft. Long Term...High pressure to our southwest will keep winds and seas below SCA criteria on Tuesday. Southerly winds will then increase on Wednesday ahead of an approaching frontal boundary with SCA conditions likely as winds gust up to 25-30 kts and seas build to 4-7 feet. Distant Hurricane Larry will then begin to allow for increasing seas towards the end of the week with seas of 6-12 feet possible across the outer waters and 4-8 feet across the bays. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...Ekster SHORT TERM...Cornwell LONG TERM...Tubbs AVIATION... MARINE...
Area Forecast Discussion
National Weather Service Houston/Galveston TX
646 PM CDT Sun Sep 5 2021 .AVIATION... A line of showers and thunderstorms ahead and along a weak cold front will approach SE TX this evening. The line has begun to weaken and not sure how far south the line will get this evening. Still plenty hot and there is decent CAPE and PWATs in advance of the front so will carry VCTS for northern TAF sites and see how things evolve. Leaned toward the HRRR which shows the line weakening and then blossoming again after 09z further south affecting the Houston terminals for the morning push. Will carry VCSH after 09z through the morning. Will carry a VCTS for central and southern TAF sites for Monday afternoon but confidence with additional development is low as models dry things out quickly after 18z. 43 && .PREV DISCUSSION... /ISSUED 308 PM CDT Sun Sep 5 2021/ DISCUSSION... Showers have had a hard time getting started so far today, though that is expected to change for the Houston Metro/I-45 eastward as a weak front droops into the region. Though the rain setup does not overall look particularly impressive, the strongest cell or two may manage some isolated heavy rain. The deeper we go into the new week, the lower rain chances will go as some drier air filters into the region and high pressure attempts to build back. Along with the lower rain chances, we`ll also see above average temperatures with highs away from the Gulf looking to rise into the middle to upper 90s multiple days. Finally, we will continue to keep an eye on Invest 91L and its potential for development as it lifts northward across the Gulf over the next several days. Confidence though, is increasing that this feature will be kept well to our east. SHORT TERM [Monday Through Monday Night]... The remainder of this afternoon`s weather pattern will be very similar to what we saw yesterday. Despite higher PW air along our eastern counties again today, subsidence still seems to be winning out and our radar remains quiet inland. With high pressure overhead and light SW flow, the sea-breeze will begin to push inland over the next few hours and at most might kick up some isolated showers along our coastal areas before dissipating around sunset. Meanwhile, a front currently passing through DFW`s area will sag further south and is expected to reach our northern counties by late this evening. Therefore, isolated to scattered showers and storms are expected along the frontal boundary as it pushes south overnight and reaches the coast by morning. WPC has placed our eastern and northern portions of our CWA in a marginal risk for excessive rainfall tonight, but as the front becomes more E/W oriented, it`s low-level moisture transport will weaken, so not expecting much of a risk tonight. By tomorrow, the frontal boundary will be stalled across our southern CWA and act as a focus for showers throughout the day. With daytime heating, coverage and intensity of these showers are expected to increase throughout the day and peak late afternoon. Rain chances will also be enhanced by a broad tropical trough in the Central Gulf expected to migrate north and bring a surge of deep tropical moisture along the northern Gulf Coast. Forecast soundings show PWs climbing to 2.1-2.2 inches and CAPE peaking at ~2200 J/kg. Therefore, WPC has placed our southeastern counties in a marginal risk for excessive rainfall. Any training storms and slow moving storms are capable of producing heavy rainfall tomorrow. By the evening with the frontal boundary still stalled across our southern counties, PoPs will remain near 30-60% overnight. Regarding temperatures, tonight will be warm and muggy again with lows reaching the mid to upper 70s inland and near 80 along the coast. Tomorrow`s high temperature are expected to reach the lower to mid 90s, a slight cool down thanks to the FROPA. But for tomorrow night, optimistically, our northernmost counties will reach the lower 70s and perhaps even the upper 60s for our most rural sites.. Gasp! LONG TERM [Tuesday Through Sunday]... By Tuesday morning, there will likely be precious little left of the upper trough/weak front that was the story of the short term forecast. We may have some lingering vorticity left aloft in a big gap in the subtropical ridge, but it will be entirely cut off from the main trough heading towards the Canadian Maritimes. We could still see some showers and storms on Tuesday around the coast, particularly if the boundary doesn`t make it as far south as progged in the model guidance. For the rest of the week and into the weekend, the main story will be the rebuilding of the subtropical ridge, and the filtering in of some drier air from the north behind the weak front. Both of those will allow for afternoon temperatures to shoot up above seasonal averages and into the middle to upper 90s away from the coast (and even to around or just above 90 to the Gulf). While the surface pressure gradient won`t be too tight, we should see enough onshore flow - especially in the wake of 91L - to keep overnight lows from falling out of the 70s...so if you like it a bit cooler, we look to get the worst of both worlds there with both above average temps overnight and during the day. This setup should effectively cut off rain chances, at least over the vast majority of the area late in the week. With high pressure and precipitable water progged to fall to around or even below an inch, convection seems a long shot. Depending on how deep the drier air manages to work, guidance suggests we could still squeeze out some showers/storms over the nearshore Gulf waters and maybe, maaaaaaaybe right on the immediate coast, but that should be about it. As some deeper Gulf moisture returns to the region late in the weekend or early next week, we should see higher humidity and perhaps even some rain chances creeping back into the picture. The potential fly in the ointment for this forecast? Invest 91L. My forecast reflects the increasing confidence that the bulk of the Gulf moisture (and any tropical cyclone, if there is one), will ride east of the incoming boundary and get caught up in the last little bit of influence from the passing northern stream trough and take that break in the subtropical ridge right up into the North/Northeast Gulf coast and Southeastern states. This seems pretty clearly the most likely scenario, and the one that the deterministic guidance strongly favors. But there are a couple lonely members of the GEFS that really have something against Freeport/Matagorda, and take 91L as a tropical cyclone over their way. This very much has "SoYoureTellingMeTheresAChance.gif" energy, but theoretically, yes, it is still on the table. We will continue to monitor things and start raising a ruckus if things change for our area - we just ask you recall that it is peak hurricane season and are prepared accordingly. MARINE... Light to moderate winds are expected through the first half of the week along with seas below three feet. Showers and thunderstorms will be possible as a weak front drops into Southeast Texas tonight and tomorrow, then rain chances will be relatively low for much of the coming week along with a general land/seabreeze diurnal pattern. Deeper Gulf moisture pushing back into the area may start to boost rain chances at the end of next week. Mariners should closely monitor the forecasts regarding potential tropical cyclone development in the Gulf of Mexico towards the middle of the week. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 75 94 72 96 70 / 30 20 10 10 0 Houston (IAH) 78 94 75 94 74 / 30 50 40 20 10 Galveston (GLS) 80 91 79 90 79 / 30 40 60 30 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ Discussion...99 Aviation/Marine...99
Area Forecast Discussion
National Weather Service Lake Charles LA
1000 PM CDT Sun Sep 5 2021 .UPDATE...The previous forecast remains on target with only a minor update to the precip grids conducted to reflect current trends. && .PREV DISCUSSION... /issued 623 PM CDT Sun Sep 5 2021/ DISCUSSION... For 09/06/2021 00Z TAF Issuance. AVIATION... Some scattered convection and associated cloud cover around the region this evening. Expect some of this activity to begin to fizzle out following sunset... But, a diffuse and slow moving frontal boundary will sink towards the area overnight, so will see a reintroduction of VCTS and lowered CIGS accordingly. TEMPO groups may be added later, but high res guidance suggests activity should remain fairly scattered. Additionally, given the weakness of the boundary, winds will remain light and variable through much of the night enhancing the potential for the typical patchy BR/FG development after midnight. Some question of how far south the boundary makes it, but likely will see at least some northerly winds pick up after daybreak tomorrow as it stalls and washes out nearby. With the stalling of the boundary, will also see a continuation of vicinity type activity through the day. Most guidance prevails VFR... Though any increased convective coverage and activity directly over the terminals will result in more deteriorated conditions. 50 PREV DISCUSSION... /issued 344 PM CDT Sun Sep 5 2021/ DISCUSSION... SHORT TERM [Today through 12Z Wednesday]... Showers and thunderstorms will be expected to continue developing (primarily for southern areas) for the remainder of this afternoon into this evening. A few storms will be possible for Central LA through the evening. Storms will dissipate after sunset but an approaching frontal boundary from the north will lead to forced uplift and formation of storms in our area during the overnight hours. The HRRR is showing some storms making their way through our area starting around 04Z and progressing towards the coast by 12Z. PWATs 2.00-2.25 inches will be expected heading into Monday. The frontal boundary will be expected to stall over our area Monday into Wednesday. Precipitation chances will be enhanced by daytime heating. WPC has our area in a Marginal Risk of Excessive Rainfall through the period. A significant amount of moisture present in our area along with the stalling frontal boundary means that there will be persistent chances for showers and thunderstorms over the next few days. Areas that get sustained and persistent rainfall could see flooding. 55 LONG TERM [Wednesday through Sunday]... As we start the long term period, our weak frontal boundary is progged to be meandering/washing out in vicinity of the forecast area, while another, more substantial cool front is noted to our northwest, extending from the Mid-South through the ArkLaTex. At the same time, the much talked about area of disturbed weather currently over the wrn Caribbean/Yucatan Peninsula is progged to be moving newd across the cntl Gulf as a trof of low pressure. Combo of these features, along with plentiful Gulf moisture in place across the area (forecast soundings indicate PWAT values as high as 2.2 inches, mainly over lower Acadiana) should lead to scattered/numerous showers/storms by Wednesday afternoon, primarily over the sern zones. By Thursday, the reinforcing front should be slipping into the forecast area, squeezing sufficient moisture for further convection to mainly the coastal areas and lower Acadiana. The main impacts of the front for now appear to be a nice lowering of dewpoints across the nrn zones, making for a more pleasant afternoon despite temps into the mid 90s. With the front slipping off the coast by early Friday, dry weather looks on tap for the early portions of the weekend. Wake up temps are progged by guidance to be in the mid/upper 60s (a degree or two below seasonal norms) for a large portion of the forecast area through Saturday. By Sunday, the front washes out and return flow begins moistening the lower levels again...look for widely scattered showers/storms to also return to the region. 25 MARINE... Weak onshore flow and low seas will prevail this evening outside of scattered thunderstorms. Storms will become more widespread Monday through Wednesday as a frontal boundary stalls across the region. Winds will alternate between offshore and onshore through the first half of the week depending on the exact location of the boundary. && .PRELIMINARY POINT TEMPS/POPS... AEX 74 89 68 92 / 70 40 10 30 LCH 76 89 72 90 / 60 60 40 50 LFT 76 89 73 91 / 40 80 40 60 BPT 74 90 71 91 / 60 60 40 40 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$
Area Forecast Discussion
National Weather Service Elko NV
257 PM PDT Sun Sep 5 2021 .SYNOPSIS...Strong high pressure bring hot afternoons and dry weather to the region for the next few days. Daytime temperatures will be approaching record highs on Tuesday and Wednesday. && .SHORT TERM...Tonight through Tuesday evening. Amplified ridge will be locked over the Intermountain West region for the next two days. Some record high temperatures are expected by Tuesday, like Winnemucca, Eureka, and Ely. With the dry nearly cloud free air mass, large diurnal swings are expected with morning lows in the 40s and 50s. The air will not be free of smoke particulates, although the amount of smoke from the Dixie fire has lessened (still plenty of smoke). The HRRR smoke model keeps the smoke/haze across northern Nevada, but better air exists over Nye and White Pine counties. .LONG TERM...Tuesday night through next Sunday Guidance continues to have a fair amount of agreement only through Wednesday night with respect to weather conditions remaining quiet. Wednesday should be the warmest day of the long term with highs mostly in the 90s, potentially rivaling records in some locations across the CWA. The center of the high pressure looks to shift south and eastward over the course of the second half of the week. Temperatures slowly trend down as relatively cooler air has the opportunity to advect into the region, and we may see highs that are only in the 70s and 80s accompanied by overnight lows in the 40s and 50s as we get to the weekend. These temps are closer to what we would expect for this time of the year. Lower confidence lingers around what the resulting weather conditions will be. Pulses of mid-level moisture may help in the development of some dry thunderstorms beginning Thursday, with a mix of dry thunderstorm and shower activity on Friday, onward. There isnt anything at this time supporting any confidence behind rainfall totals, but it looks like the best chance for some much needed rain accumulation could be in northern Nye and White Pine counties. && .AVIATION... Brief periods of MVFR visibility is possible from smoke and haze from KWMC-KBAM-KEKO. Otherwise VFR dominates with the sky cover mostly cloud free. && .FIRE WEATHER... Transport winds will be light for the next few days with dry conditions prevailing. The hazy conditions persist, particularly across northwest Nevada. Isolated dry lightning remains a possibility late in the week. This bears watching given the forthcoming hot and dry afternoons and receptive fuels across much of the region. While some moisture may creep into eastern Nevada, cluster analysis keeps an elongated subtropical high core over the southwest CONUS. This pattern does not favor moisture advection into eastern Nevada. && .LKN WATCHES/WARNINGS/ADVISORIES... None. && $$ 88/84/88/88
Area Forecast Discussion
National Weather Service Marquette MI
728 PM EDT Sun Sep 5 2021 .SHORT TERM...(This evening through Monday) Issued at 416 PM EDT SUN SEP 5 2021 Water vapor imagery and RAP analysis show a mid-level trof over Ontario and across the Great Lakes region. The mid-level low that was centered over far ne Manitoba 24hrs ago has opened up, but its well-defined vort max is diving sse and is nearing nw Lake Superior attm. Convection has been increasing underneath it and its associated mid-level cold pool. Closer to home, cool, cyclonic flow under troffing and some instability have been supporting isold to sct shra development today. So far, no lightning has been detected with any of the shra here or upstream. With the rapid increase in diurnal cloudiness during the morning, temps currently are mostly in the 60s F, but a few lwr 70s are noted s central. As vort max and cold pool aloft (500mb temps around -21C) passes across the fcst area this evening, shra coverage/intensity will peak. As was the case with previous model runs, latest runs show greatest instability over Lake Superior where the relatively warm lake waters boost sfc/mixed layer Td. Instability diminishes inland from the lake with very little to almost none noted well inland. Over Lake Superior, SBCAPE generally peaks in the 500-1000j/kg range, shifting w to e in the 21z-06z time frame, essentially corresponding to the passing 500mb cold pool. Per the Szilagyi waterspout nomogram, conditions may sneak into waterspout potential thru the evening hrs due to convective cloud depths to around 20kft and water sfc to 850mb delta-T increasing to around 13C. Although no mention of thunder was included in fcst, wouldn`t be surprised if a couple of the shra manage to be deep enough to generate a lightning strike or two. Shra will mostly end from w to e during the night, but will probably linger over the e into Labor Day morning due to marginal overlake instability. With increasing breaks in the cloud cover, especially interior w half, and diminishing winds, traditional cold spots should see temps fall toward 40F. Temps will range up to the mid 50s near Lake Superior. Lingering isold light shra will end over the e by aftn. Otherwise, expect a dry Labor Day as weak shortwave ridging arrives btwn the departing trof and the next approaching shortwave reaching the Canadian Prairies. 850mb thermal trof will be departing to the e. Before shifting farther e, expect some diurnal cu to blossom in the morning over the w before dissipating. However, high clouds will already begin increasing as strong waa/isentropic ascent regime spreads toward the Upper Lakes in response to the next approaching shortwave. Expect lake cloudiness and an expansion of diurnal cu/stratocu e with later departure of the thermal trof. Those clouds will begin clearing out during the aftn. High temps will range from the mid 60s to lwr 70s F. .LONG TERM...(Monday night through Sunday) Issued at 331 PM EDT SUN SEP 5 2021 Ridging near the four-corners region and eastern US troughing amplify this week. The primary feature of interest is a surface low that develops and intensifies as it tracks east-northeast through the Upper Great Lakes region on Tuesday into Tuesday night. This seasonably strong surface low results in thunderstorm chances and gusty winds as it tracks through our area. Gales seem increasingly likely across eastern Lake Superior Tuesday night. Seasonably cool weather is expected through Thursday with warm air advection returning on Friday. Weekend forecast is uncertain, but more zonal flow should result in temperatures closer to seasonal averages. Sky cover and precipitation chances increase early on Tuesday as a surface low develops over northern MN and tracks east-northeast. The low track is still somewhat uncertain, but model guidance seems to continue the northward trend noted yesterday. 00Z ECMWF and 00Z CMC guidance track the low north of Lake Superior with 00Z GEFS guidance tracking over the lake. A middle of the road approach is favored at this time considering warm lake temperatures imply a preferred baroclinic zone along the north shore. 12Z NAM/GFS guidance seems to be in good agreement showing the surface low occluding over Lake Nipigon then meandering east-southeast near the shoreline. Irrespective of the exact location, an occluding low that lingers across N/NE portions of Lake Superior before tracking northeast toward James Bay seems increasingly likely. Operational guidance indicates the surface low deepens to ~990mb and the NAEFS continues to highlight MSLP values being at or near climatologic minimums. Gales are therefore increasingly likely, particularly over eastern Lake Superior. Strong winds may provide the most widespread impacts of Tuesday storm system, but widespread precipitation is also expected. With a low track farther to the north, our CWA is deeper into the warm sector where isolated to scattered thunderstorms should occur. The final hours of the 12z HREF (especially the NAM nest and NSSL) indicates a thunderstorm complex tracking southeast from the arrowhead of MN early on Tuesday morning within a strong warm air advection regime. While I`m not confident in thunderstorm location, a strongly forced line of elevated storms seems increasingly likely across the west in the morning. More mixed layer thunderstorm development seems increasingly likely across the east in the afternoon. Digging into specifics of the near-storm environment may be futile at this time, but the typically too aggressive 3km NAM shows a plume of 3000+ J/kg MUCAPE rooted around the 825 mb layer. Bulk shear in the cloud bearing layer doesn`t appear particularly impressive (~30 knots), but should be adequate for a hail threat. Elevated storms don`t typically pose much of a damaging wind threat, but stronger storms may mix the ~50 knot LLJ down toward the surface. Seasonably chilly weather continues through Thursday with lake effect clouds and showers expected for NW wind belts. Subtle shortwaves embedded within NW flow aloft combined with diurnal heating may locally enhance lake effect showers. Adjusting surface parcels to ~17C water temperatures yields a few hundred J/kg of skinny CAPE that might be enough for thunderstorms. A warmer air mass moving in on Friday will bring an end to lake effect clouds/precip. Model guidance diverges this weekend with difference primarily related to amplitude of incoming shortwave and associated cold front. 12Z ECMWF advertises a much stronger cold front compared to GFS/CMC/UKMET guidance. Forecaster confidence is low for next weekend, but the flow regime should become more zonal with time indicating more seasonable temperatures. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 727 PM EDT SUN SEP 5 2021 Cool, cyclonic flow was resulting in sct shra and a few tsra across the, west, north and eastern Upper Peninsula this evening. Impacts to TAF sites will be brief with possible MVFR CIGs and brief gusty winds. The rest of the TAF period is looking like VFR conditions for KSAW and KIWD. For KCMX low level moisture combined with a heating after sunrise should produce a period of MVFR CIGs before mixing lifts the cloud bases to VFR later in the morning. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 416 PM EDT SUN SEP 5 2021 Thru tonight, low pres over James Bay will only drift e while a high pres ridge over the Dakotas and Manitoba shifts to MN and northern Ontario. Under a cool air mass and relatively tight pres gradient, nw winds of 15-25kt will generally prevail across Lake Superior this evening with some gusts up to 30kt over the e half. Conditions this evening may also become marginally supportive of waterspouts to occur with some of the showers moving across Lake Superior, particularly from nw of the Keweenaw to s central portions of the lake. Winds will slacken some over the w overnight as high pres ridge moves closer. With the high pres ridge arriving on Labor Day, expect winds mostly under 15kt over the w half of Lake Superior. Winds will diminish to mostly under 15kt e during the day. On Tue, deepening low pres will track e across northern Ontario, passing just n of Lake Superior. Ahead of it during Mon night, southerly winds will ramp up to at least 15-25kt, strongest across eastern Lake Superior. These southerly winds may even gust to 35kt gales over the e half of the lake late Mon night/Tue morning. As the cold front associated with the low crosses Lake Superior, expect w winds of 20-30kt to develop Tue, then shift nw Tue night into Wed. It`s looking increasingly likely that the nw winds will increase to 35- 40kt gales Tue night thru Wed morning, at least over the e half of Lake Superior. Wind will then slowly diminish w to e Wed aftn/night with winds under 20kt across Lake Superior by sunrise Thu as high pres ridge moves closer to the area. Winds are then expected to remain under 20kt on Fri. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Beach Hazards Statement until 9 PM EDT this evening for MIZ006. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...EK AVIATION...NL MARINE...Rolfson