####018007566#### FXUS63 KMQT 181836 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 236 PM EDT Sun May 18 2025 .KEY MESSAGES... - Light rain and drizzle will end this afternoon and early evening. - Mostly dry period tonight through Wednesday. - Below normal temperatures expected this weekend. Patchy frost will be possible this week. && .SHORT TERM /THROUGH TODAY/... Issued at 119 PM EDT Sun May 18 2025 Overcast skies have dominated the region this morning thanks to a shortwave pressing through the region and continued surface troughing extending back over the region from its parent low now over New England. With the near surface environment being moist and cool, a dreary day has been observed with light rain over the east and pockets of drizzle elsewhere downwind of Lake Superior. Temperatures have been observed in the 30s except for those in the south-central, whom have warmed into low to mid 40s. For the rest of today, the synoptic and meso forcing for precip will continue to wane while high pressure begins to extend its influence over the area. While this will help bring precip to an end, overcast skies should linger until later this evening. Daytime temperatures may climb a few degrees and more widespread 40s may be realized, maybe low 50s south-central. && .LONG TERM /TONIGHT THROUGH SATURDAY/... Issued at 150 PM EDT Sun May 18 2025 Surface high will build into the region tonight ahead of mid-level ridging pressing eastward into the region. This will help kick the earlier shortwave east of the region and help clear skies across our forecast area. Mid-upper level ridging centered over Ontario will hold into Tuesday when it retrogrades westward into Manitoba in response to the phasing process beginning between a shortwave moving southeast through eastern Ontario and a robust shortwave transiting the middle-Mississippi River Valley. Wednesday, the phasing becomes more pronounced, with the shortwave becoming negatively tilted and closing off before dropping through the our forecast area and then into the Ohio Valley Friday. The effect of this progression will be a dry period tonight through at least Wednesday night, save for the low-med probability (<40% chance) showers may extend into the counties bordering the stateline Tuesday afternoon and evening. In this period, the airmass at 850mb will begin near -3C but gradually warm to +3-4C Tuesday before cooling again Wednesday night below zero C. This will support daytime temperatures in the 40s and 50s Monday, then more widespread 50s to near 60F each day afterwards, except upper 40s near Lake Superior. Daytime mixing and the dry airmass Monday/Tuesday will also yield RH values dipping into the 30s and 20s. Interior west locations may fall into the teens. The cooler airmass will also make for breezy northeast winds, potentially 20-25mph, both days. 30- 35mph looks possible for the Keweenaw, mainly on Tuesday. At the moment, elevated fire weather conditions are not expected given the cooler conditions, but is worth monitoring in the event we warm into the upper 60s in the interior west and east. Widespread 20s across the interior west half and near 30F or the low 30s are expected tonight. Thereafter, interior locations should expect 30s each night while lake-side communities dip to near 40F. This may yield patchy frost most nights this week, particularly tonight for all interior locations and maybe Monday night in the interior west. Shortwave associated with the rotating mid-upper level low will push through Wednesday night followed by moist, northerly, upslope cyclonic flow, altogether manifesting the next best chance for rain Wednesday night and Thursday. This system will gradually shift east into the Atlantic with deep troughing persisting along the east coast through the weekend. Ridging will press east across middle America upstream, but a few shortwaves pushing southeast into the downstream trough looks possible for our neck of the woods. This keeps low probabilities of rain (<25%) Friday for our eastern forecast area and future forecasts may include the same for Saturday. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 236 PM EDT Sun May 18 2025 Conditions at all terminals have improved to IFR and MVFR this afternoon and further improvement to MVFR and then VFR is expected this evening. Northerly upslope winds will keep some scattered clouds over KIWD/KSAW overnight. && .MARINE... Issued at 150 PM EDT Sun May 18 2025 Light rain has been observed on Lake Superior today, mainly across eastern Lake Superior. These showers pushed east as the parent surface trough and mid-level shortwave began to lose their influence over the area and a sprawling surface high shifted into Hudson Bay, thereby extending ridging into the Upper Great Lakes. Winds have mostly been observed in the 20s central and east and teens in the west. As the high continues to press its reach into the region this afternoon, winds should continue to lighten. Winds are expected to increase from the northeast tomorrow morning and again on Tuesday as the parent high pressure over Hudson Bay and a developing low pressure system over the Central Plains brings a modest pressure gradient overtop western Lake Superior; this gradient is expected to be amplified during the daytime hours as the warming over Minnesota and Wisconsin will locally strengthen the pressure gradient between the land and water. Northeast winds of 25 to gales of 35 knots develop over the western arm of the lake Monday and Tuesday, with the strongest winds expected in the far west funneling into the Duluth Harbor. Ensemble guidance continues to highlight >60% chance for gale force gusts near Duluth and the Apostle Islands Monday afternoon/evening, peaking higher to >80% at the very head of the lake into Duluth Harbor. In response, Gales Warnings have been posted in the far western lake 16z Monday to 03z Tuesday. A short break in gales is expected overnight into Tuesday, though gusts will still be reaching as high as 25-30 kts. As the parent low pressure system travels eastward through the MS River Valley Tuesday towards the Lower Lakes, gusty NE winds pick back up over the same region in the west on Tuesday. Guidance is in good agreement on 35-40 kt NE gales ramping up Tuesday morning and persisting through much of the afternoon before dying down below gale force ~00z Wednesday, with 20-30 kts still lingering into the overnight hours. The EC Ensemble even highlights 20-40% chance for 50 kts gusts within a narrow region of the Duluth Harbor area Tuesday afternoon. Waves heights will build as high as 8 to 10 feet down into Duluth Harbor Monday and Tuesday. Behind the departing low, lingering ~25kt gusts simmer down to ~20kt northerlies Wednesday evening. N winds 15-20 kts remain Thursday as a weaker pressure gradient remains overhead. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Gale Warning from noon EDT /11 AM CDT/ to 11 PM EDT /10 PM CDT/ Monday for LSZ162. Lake Michigan... None. && $$ SHORT TERM...JTP LONG TERM...JTP AVIATION...JTP MARINE...BW ####018004786#### FXUS62 KMLB 181839 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 239 PM EDT Sun May 18 2025 ...New KEY MESSAGES, DISCUSSION, MARINE... .KEY MESSAGES... Issued at 210 PM EDT Sun May 18 2025 - Hot and dry weather persists into mid week with near record high temperatures forecast and peak heat indices rising to 100-105. Worsening/expanding drought conditions are forecast. - A weak front will bring low to medium rain chances back into the forecast mid/late week. Onshore flow behind the front will bring slightly lower (more seasonable) temperatures. && .DISCUSSION... Issued at 210 PM EDT Sun May 18 2025 Rest of Today-Tonight...No record highs as of 2 PM, though temperatures continue to climb into peak heating hours. So far, temperatures have reached the upper 80s to lower 90s, with some cooling into the mid-80s for coastal areas that have seen the sea breeze pass through. Have maintained a small (~20%) chance for showers late this afternoon into early this evening along the sea breeze as it moves inland generally south of Orlando. However, this is low confidence, with the 15Z XMR sounding finding very dry air above 875mb. Regardless, dry conditions will prevail through the overnight for a vast majority of the forecast area. Warm overnight lows in the lower to mid-70s are expected. Monday-Wednesday...High pressure continues, though it will shift eastward away from the local area into Wednesday. Dry conditions prevailing, with a small (less than 20%) chance for a few showers over the interior Monday afternoon. Southwest flow will continue to produce near-record high temperatures each afternoon. The best chance for records will be over the interior, with the weak sea breeze able to provide limited relief for coastal areas. Nonetheless, high temperatures in the 90s are forecast, with a few locations approaching the upper 90s Monday and Tuesday. Heat indices are forecast between 100-105 degrees, with most areas in a Moderate HeatRisk. The Orlando area, however, will see a Major HeatRisk through mid-week. Residents and visitors should use caution and practice heat safety this week. Warm and muggy lows in the lower to mid-70s. Thursday-Sunday...Our best shot for rain chances this week looks to be Thursday, when a low pressure system moves eastward through the Mid-Atlantic and Northeast. This feature is forecast to drag a weak cool front through the local area Thursday into Thursday night. Increasing moisture and weak forcing are expected to be enough to produce isolated to scattered showers across the area (PoPs 20-30%). A few lightning storms also cannot be ruled out. Behind the front, moisture return by the weekend could cause isolated showers/storms to linger. However, most areas look to remain dry. Onshore flow is forecast to keep temperatures "cooler" (i.e. closer to seasonal averages), assisting a stronger sea breeze. However, high temperatures in the upper 80s to lower 90s will continue. && .MARINE... Issued at 210 PM EDT Sun May 18 2025 Generally favorable boating conditions prevail through Wednesday, as high pressure persists over the local area. Light southwest winds overnight and in the mornings will back southeasterly and increase to 10-15 kts along the coast in the afternoons as the sea breeze develops. Seas 1-3 ft. A weak cool front will pass through the local waters Thursday into Thursday night. Isolated to scattered showers and storms will be possible. Westerly winds up to around 15 kts Wednesday night will veer onshore into Friday. Seas building to up to 4 ft in the Gulf Stream. && .AVIATION... (18Z TAFs) Issued at 125 PM EDT Sun May 18 2025 VFR conditions are forecast through the rest of today and into tomorrow. Light southwesterly winds across the interior persist, with winds along the coast becoming onshore as the east coast sea breeze moves inland. Light and variable winds anticipated overnight, picking up out of the west-southwest across the interior and out of the east along the coast from TIX southward. Rain is not anticipated near the terminals. && .PRELIMINARY POINT TEMPS/POPS... DAB 70 94 72 94 / 0 10 0 10 MCO 74 97 75 97 / 0 20 0 10 MLB 74 91 74 92 / 0 10 0 10 VRB 72 92 73 93 / 0 10 0 10 LEE 71 95 73 95 / 0 10 0 10 SFB 72 97 73 97 / 0 10 0 10 ORL 74 97 75 97 / 0 20 0 10 FPR 72 92 72 92 / 0 10 0 0 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ DISCUSSION...Leahy AVIATION...Tollefsen ####018003414#### FXUS63 KUNR 181839 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 1239 PM MDT Sun May 18 2025 .KEY MESSAGES... -Unsettled pattern continues this week -Widespread rain amounts of 1-2 inches are expected through Monday night, highest in the eastern Black Hills and adjacent foothills where locally higher amounts are possible -Snow can be expected in the Black Hills tonight into Monday night above 5500 ft, with 2-4 inches possible above 6000 ft -Cool through mid week with some warming for the second half of the week && .DISCUSSION...(This Evening Through Sunday) Issued at 1238 PM MDT Sun May 18 2025 Deep upper trough now pushing through the Rockies today and will support widespread rains and some snow, mainly at high elevations. Scattered showers and thunderstorms are developing this afternoon with activity expected to increase in coverage through the day and evening as LSA and moisture both increase. Severe weather is not expected, but small hail will be possible with any TS. Breezy SE winds will continue as a LLJ remains over the region. The strongest winds will be across far NW SD where sustained winds of 25 to 35 mph and gusts to 50 mph can be expected. Will leave the wind adv as is. As the system shifts east, the associated trowel will remain over the region, supporting a long duration of precipitation through Monday night as appreciable moisture wraps into this system. Models are still indicating widespread amounts over an inch across much of the FA, with the highest amounts (locally 2-3 inches) expected along the eastern slopes of the BH where upslope enhancement will be in place. High elevation snow is also expected with this system, esp areas above 6kft where 2-5 inches will be possible. Main deformation zone and associated precip will begin to exit the region Tues with a few showers lingering Tues afternoon. Some snow will also be possible on the northeast WY Plains and some of the western SD Plains late Monday night and Tues morning if precip lingers as temps will certainly be cold enough. Not expecting more than a dusting on the Plains, confined to grassy surfaces. Things will dry out and warm up by the middle of the week, however semi- active westerly flow will persist with near daily chances for showers continuing along with seasonal temps through the end of the week. && .AVIATION...(For the 18Z TAFS Through 18Z Monday) Issued At 1120 AM MDT Sun May 18 2025 IFR conditions with intermittent -RA and low CIGS will persist at the KRAP terminal through the valid TAF period with IFR conditions arriving at the KGCC terminal during the overnight hours. There is a chance for some -TSRA/TSRA to impact the terminal between 22-23z, which could bring gusty and erratic winds to the terminal, there is also a chance for -TSRA/TSRA at the KGCC terminal between 18-22z. Widespread -RA with gusty southeasterly to easterly winds will impact the terminals between 23-06z with wind gusts between 35 to 40 knots. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...Wind Advisory until 6 PM MDT this evening for SDZ001-002-012-013- 073-078. WY...None. && $$ DISCUSSION/KEY MESSAGES...JC AVIATION...Woodward