Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/22/23

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
910 PM CDT Sun May 21 2023 .UPDATE... Issued at 909 PM CDT Sun May 21 2023 Current forecast is on track, therefore no changes made at this time. && .SHORT TERM...(This Evening through Monday Night) Issued at 220 PM CDT Sun May 21 2023 Main concern is the ongoing smoke overhead from the Canadian wildfires which will continue through the short term. The main challenge is how it affects our overall temperatures, especially highs on Monday. Today, the smoke really did not impact temperatures and has stayed more aloft (as forecasted). Temps got to 81 degrees here at the office around 1 PM. 79 degrees was reported at Pierre, and 81 at Mobridge around 2 PM to give a few examples. Geocolor satellite imagery showed the shortwave over the central CWA earlier this morning with the smoke wrapped around the vort and behind it, as winds aloft are out of the northwest. Ensembles plus short term models continue to show this shortwave/surface trough pushing southeast with the center of the vort over the southern/southeastern part of our CWA by 00Z Monday. At the same time, the ridging pattern continues with most of the Rockies` area under the crest of the ridge. By tonight through Monday, this ridge will push more east with most of the CWA under the crest of the ridge, resulting in even warmer air at 850mb. Our next mid/surface low will start to inch closer to the CWA, from the northwest, through the day on Tuesday. Through the afternoon, dewpoint values across the area have ranged in the 40s into the mid 50s across the CWA. With this slight moisture and lift from the surface trough/shortwave, CAMS/HREF hint at maybe some isolated precip over Clark/Codington/Hamlin/Deuel counties with most of the precip to our south in Sioux Falls WFO area. SB/MU Cape per HREF will be at or below 1000 J/kg in this area so not much in the way of organized thunderstorms as most of the better shear is to our south. HREF paintball does show some cells>40 dbz in this same area. Because of this, I did add in just a slight chance of pops here late this afternoon and evening, even though RH values at the surface remain low. We cannot rule out rumbles of thunder as dbz>40 with MUCAPE>50 ranges from 10-30% probability in this same area per HREF. HREF continues to hint at some possible pops once again for Monday afternoon along a weak surface boundary (weaker than the one this evening). CAPE values will be at or below 1000 J/kg once again. Several soundings continue to show dry air at the surface but I went ahead and added in chance of sprinkles to show for these chances, although fairly low amount of confidence. HREF/RAP indicates 500mb winds will be out of the north/northwest tonight through at least early Tuesday morning. Right now, the smoke is aloft over the CWA as Rap vertically integrated smoke model shows the plume with values over 100mg/m2 and continuing over the area through at least Monday. This is creating and will continue to create that milky/hazy look. Rap near surface smoke model shows most of the concern to our west/northwest over western South Dakota into ND/MT. For example, in Dickinson ND, visibility was as low as 4 SM at 10AM earlier today. However, near surface smoke values do creep up a bit this evening then decrease overnight and increase again Monday. This may result in a continued decrease in air quality and slight viz reduction.( Currently the eastern side of the state and Mobridge area are in yellow aka moderate index, as of 2:15 PM). With the smoke concern, per the previous shift, I left the smoke mention in the grids across central and western CWA through the short term. This may need to be extended eastward as the trough moves southeast. Sky cover remains at 30-40% as well. 850mb temps overnight will range from ~14C to 17C across the CWA with values at Tuesday 00Z up to 16-20C. However, as mentioned, the smoke may knock off a few degrees for highs on Monday. Overnight lows will range in the 50s with highs on Monday ranging from the upper 70s over the Coteau to the mid 80s. .LONG TERM...(Tuesday through Sunday) Issued at 220 PM CDT Sun May 21 2023 A blocky mid level pattern is expected to persist over the CONUS through much of the period, with upper trofs over the eastern and western CONUS, and a ridge in between. Upper ridge ring of fire convection can`t be ruled out entirely during the period, but the better chances for measurable rain will come toward the end of the week. At that time, energy lifting out of the western continent will help nudge the ridge to the east, and allow for better LL moisture/instability to develop over the forecast area. However, severe chances still don`t look great given relatively light winds aloft, and therefore minimal deep layer shear. Generally speaking, with ridging aloft over the region sfc temperatures will favor above normal for most of the long term. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) Issued at 624 PM CDT Sun May 21 2023 Terminals KABR,KATY,KPIR,KMBG VFR conditions will prevail across the area tonight and through the day Monday. Southerly winds may gust in excess of 20 knots Monday afternoon. Elevated wildfire smoke from Canada will remain over the region through the TAF period. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Parkin SHORT TERM...MMM LONG TERM...TDK AVIATION...Parkin
Area Forecast Discussion
National Weather Service La Crosse WI
955 PM CDT Sun May 21 2023 .DISCUSSION...(This evening through Sunday) Issued at 204 PM CDT Sun May 21 2023 Key Messages: - Smoke moving into the area tonight and remaining across the area into Tuesday. - Small chance of showers from Tuesday night into Wednesday. - Additional shower and storm chances for the Memorial Day Weekend. From Tonight into Tuesday The RAP continues to show that the western Canadian wildfires will gradually move south across the area through Monday and then linger across the area into Tuesday. High temperatures will be in the mid to upper 70s on Monday and then range from the mid-70s to lower 80s on Tuesday. The winds will be southerly at 5 to 10 mph. From Tuesday night into Wednesday The deterministic models are in good agreement that a 500 mb trough will move southeast through the Great Lakes. As this occurs, a Canadian cold front will move south into the region. With only weak convergence and surface dew points around 50 degrees, surface-based CAPES remain generally less than 100 J/kg, so only expecting isolated to scattered showers along this front. High temperatures on Wednesday will be cooler with temperatures ranging from the mid-60s to mid-70s. Friday into the Memorial Day Weekend The models continue to diverge as they struggle with the placement of a closed low over the eastern US. It ranges from the eastern Great Lakes into the Carolinas. In addition, they struggle with how fast the upper level ridge will break down over the Upper Mississippi River Valley. Due to this, there is some uncertainty on when precipitation chances will return to the forecast for late this week. Even with this uncertainty, there is general agreement that there will be at least scattered showers and storms for this time period. In addition to some uncertainty on the precipitation, there is greater spread (10 to 20 degrees) in the temperature guidance. The GEFS continues to have the coldest temperatures and the Canadian ensemble remains the warmest. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 955 PM CDT Sun May 21 2023 CIGS: surface high pressure starts to edge off to the east while the ridge a loft starts to build overhead from the west. Clouds will generally be on the sparse side as a result. However, smoke from Canadian fires continue to spread southeast and will make for a milky sky the next few days. Will run with sct250 to account for the smoke for now. WX/vsby: no impacts anticipated at this time. RAP model suggests smoke could be brought to the sfc on Tue, which could result in some MVFR vsby restrictions. WINDS: light from the south/southeast. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ DISCUSSION...Boyne AVIATION.....Rieck
National Weather Service Bismarck ND
858 PM CDT Sun May 21 2023 .UPDATE... Issued at 858 PM CDT Sun May 21 2023 The forecast remains on track. UPDATE Issued at 631 PM CDT Sun May 21 2023 Quiet conditions continue with hazy skies from smoke across the forecast area. Any reduction in visibility from near-surface smoke looks very limited at this time with a few sites down to 9 SM. Patchy smoke may reduce visibility down to as low as 6 SM in some western locations tonight. && .SHORT TERM...(This Evening through Monday) Issued at 253 PM CDT Sun May 21 2023 An upper level ridge across the Northern Rockies continues to bring subtle northwest flow into the Northern Plains. Therefore, elevated smoke from the fires up an Alberta continues to move through the region resulting in hazy skies. Near surface smoke has mostly cleared out of western and central North Dakota with some sites seeing very minor visibility reductions. The RAP Near- Surface Smoke does increase smoke coverage across the west this evening and tonight. Therefore, patchy smoke was added to the grids through 12Z Monday. Easterly surface winds could limit near surface smoke across central North Dakota tonight. Smoke will likely impact the temperature forecast as temperatures struggle to reach the lower 80s this afternoon. Smoke will keep low temperatures elevated tonight in the 50s across the state. Temperatures are forecast to climb into the lower to mid 80s across the state. As a low level thermal ridge extends up through eastern Montana. Smoke could limit temperatures tomorrow a degree or two. The surface pressure gradient will tighten up increasing winds out of the south by tomorrow afternoon. .LONG TERM...(Monday Night through Sunday) Issued at 253 PM CDT Sun May 21 2023 An upper level ridge is forecast to move across the Northern Plains the beginning half of this week bringing forth warmer temperatures. However, a quick transition to unsettled weather pattern is expected through the middle of the week. A ridging pattern will bring in a low level thermal ridge across the Northern and Central Plains. This will result in increased temperatures Tuesday with highs forecast to sit in the mid 80s to lower 90s. A wave and a warm front will move across the northwest resulting in thunderstorms and showers in the afternoon. Instability increases across the west with slow storm motion could lead to locally heavy rain. In addition PWATs are forecast to be above an inch, around 0.5 inches above normal out west. CSU machine learning severe weather forecast does highlight portions of North Dakota for the potential for severe hail. Troughing will continue to dig across Western CONUS bring in southwesterly flow aloft. A back door cold front is going to move through the state Wednesday morning causing increased precipitation chances. Multiple waves are forecast to move through the region towards the end of the week increasing precipitation chances. Temperatures are forecast to sit in the upper 70s to lower 80s for the remainder of the week. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) Issued at 631 PM CDT Sun May 21 2023 VFR ceilings and visibility are expected through the period. Removed smoke from western TAF sites based on visibility in present obs, as well as those nearby. It`s not entirely out of the question that KXWA/KDIK could see brief reductions to MVFR visibility in smoke, but confidence is low in that scenario occurring at this point in time. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Telken SHORT TERM...Johnson LONG TERM...Johnson AVIATION...Telken
Area Forecast Discussion
National Weather Service Denver/Boulder CO
807 PM MDT Sun May 21 2023 .UPDATE... Issued at 800 PM MDT Sun May 21 2023 Another surge of smoke was moving slowly southward this evening, with the leadng edge, along a line from Fort Collins to Greeley to Sterling line. In addition was spreading southwest across the higher terrain of Larimer county as well. Expect this smoke will cover much of the area late tonight through Monday. Otherwise it will remain quite overnight, except for some potential for dense fog over ern Lincoln county. && .SHORT TERM...(This evening through Monday) Issued at 248 PM MDT Sun May 21 2023 Showers and a few storms have developed over the southern Front Range mountains and Lincoln County this afternoon. Expect scattered showers and a few storms across over the high country given a marginally unstable environment (SBCAPE < 500 J/kg). Expect this to continue through the early evening hours, mainly over the high country and favoring the southern Front Range. Geocolor satellite imagery shows the next (unfortunate) wave of smoke from the wildfires in west Canada dropping southward toward Colorado thanks to progression of a shortwave trough. In the next few hours this will reach the northern Colorado border and by early evening to the Denver Metro. Some portions of this smoke plume contain thicker smoke concentrations, quite evident on satellite and it moves through Wyoming at the moment. Stations in Wyoming have reported visibility as low as 3 miles. RAP smoke forecast is consistent with the obs as it brings down a wave of higher concentration smoke into tonight. With a weak ridge and flow aloft in place for Monday, smoke will be slower to erode and will likely be around for the day. Without the smoke, it would have been a slightly warmer day than Sunday. However, given the smoke, kept highs similar to Sunday in the low to mid 70s. If smoke is thick enough, highs may not even reach those values over the plains. There is a chance for showers and thunderstorms in the afternoon. Instability and moisture will be marginal, but will support showers and weak thunderstorms. Ensembles show the better moisture over the high terrain, so it is likely storms will stay more confined to the high country and struggle to make it onto the adjacent plains where it is drier, a bit more stable, and has smoke present. .LONG TERM...(Monday night through Sunday) Issued at 248 PM MDT Sun May 21 2023 Weak ridging aloft will be over Colorado on Tuesday with very light mid to upper level winds. 500 mb winds may be less than 10 knots. Mostly sunny conditions in the morning will allow for some weak instability to build in. With the lack of a feature to provide lift, showers and storms will mainly form over the higher terrain. A couple of these showers and storms may push onto the adjacent plains. No severe weather is anticipated but there will be a flash flood threat over the recent burn areas. Otherwise, temperatures will be slightly above normal. Upper level flow will increase slightly on Wednesday as a trough over western Canada begins to influence our area. There will be better precipitable water and CAPE values as more moisture arrives. Some models are hinting at a slight shortwave trough that moves through which should lead to better coverage of showers and storms. The NBM PoPS seemed overdone as they had PoPs in the 80s across all of the I-25 corridor. There just isn`t a strong enough trough or strong enough upslope flow to warrant PoPs greater than 80 percent so PoPs were lowered. Soundings would support just enough instability and low level shear that a storm or two could approach severe thresholds. However, the severe threat would remain very isolated. Recent model runs have been showing a ridge over the Southern Plains staying slightly farther west than previous runs and that results in it staying over eastern Colorado Thursday and into the weekend. If this trend continues, our forecast area would likely see scattered showers and storms over the mountains with lower coverage on the plains. A lot can change during this period as it gets closer. One thing to keep an eye on is the threat for severe weather. The CIPS analogs continue to show a good signal for some severe weather along the Front Range. However, there is plenty of skepticism about this chance of severe weather since the flow aloft will be so weak. Flow at 500 mb fails to get above 30 knots during this stretch and the instability will not be on the high side given the near normal temperatures. Nonetheless, a few severe hailstorms may be possible. The main weather concern appears to be flash flooding in the burn areas which is discussed more below. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 513 PM MDT Sun May 21 2023 Smoke should gradually filter back in by mid evening and continue through Monday. At this time have kept visibility above 6 miles thru the period. There could be a window on Monday where visibility may drop to 5-6 miles but confidence is low on timing. Otherwise northeast winds will gradually switch to more southeast by 04z and then to drainage by 07z. Winds will be light and variable Monday morning but become east by aftn. && .HYDROLOGY... Issued at 248 PM MDT Sun May 21 2023 There will be a limited threat for flash flooding over the burn areas Monday. Scattered showers and thunderstorms are possible in the afternoon, but are expected to be lower in intensity. However, flow aloft will be quite weak. With enough moisture present to support locally heavy rainfall, it will warrant that limited threat for flash flooding. Each day during the long term period will at least have a limited threat for flash flooding in the recent burn areas. The storms will be slow moving each day due to weak winds aloft. Tuesday will have nearly stationary storms but the storms will not be particularly heavy. Therefore, a limited threat of flash flooding is forecast for Tuesday. The storms may gain some strength Wednesday through the end of the week but they will also be moving slightly faster. Wednesday may be close to having an elevated threat for flash flooding while the rest of the week and weekend will have a limited threat for now. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...RPK SHORT TERM...Mensch LONG TERM...Danielson AVIATION...RPK HYDROLOGY...Mensch/Danielson
Area Forecast Discussion
National Weather Service Burlington VT
947 PM EDT Sun May 21 2023 .SYNOPSIS... A cold front crosses the region late this afternoon into evening with a few showers around and a slight chance for a thunderstorm across northern New York. Patchy frost is possible across the Adirondacks and Northeast Kingdom overnight tonight. Plentiful sunshine albeit with some Canadian wildfire smoke aloft is on tap for Monday and Tuesday. A cold front brings the next chance potential for wetting rainfall with embedded thunder on Wednesday. The weather pattern turns more unsettled during the latter half of the week. && .NEAR TERM /THROUGH MONDAY NIGHT/... As of 943 PM EDT Sunday...Areal coverage of showers continues to decrease this evening as expected with developing northwest flow and drier air advecting into our cwa. Have noted temps continue to be 3 to 5 degrees warmer, so have made some minor tweaks to the hrly rate of fall. However, as dwpts continue to drop and drier air with clearing skies develop, expect rate of hrly temp fall to increase aft midnight. Did make some minor adjustments to dwpts, but overall fcst in good shape with some very patchy frost possible toward sunrise acrs the northern dacks and parts of northern VT, including the NEK. Previous discussion below: It has turned out to be a rather nice day across North Country with sunshine breaking out albeit with smoke from western Canada wildfires aloft. A cold front currently approaching the St Lawrence River valley in Quebec is currently sparking some isolated to scattered showers. The satellite GLM product is showing some lightning flashes upstream across eastern Ontario. After examining the latest RAP soundings and mesoanalysis, introduced slight chance thunder for our NY zones mainly west of the I-87 corridor. Any thunderstorms that do form could produce brief locally moderate rain or downpour. The front will sweep through our region late this afternoon into the evening hours, with brief showers and a wind shift from the west to northwest. Dew points drop from near 50 into the upper 20s and lower 30s through the evening and overnight hours. It will also help to clear the smoke aloft albeit only till Monday morning per the NCEP RAP vertically integrated smoke depiction. The other consideration for tonight is a brief period of patchy frost potential, mainly across the Adirondacks and Northeast Kingdom. Forecast soundings indicate that boundary layer winds should subside enough outside of the valley locales for temperatures to fall into the lower to mid 30s for these climatologically colder spots. Given that all zones are now in growing season, have hoisted Frost headlines for these zones. Monday will be quite a bit cooler especially across the northern half of our CWA. Highs will be in the upper 50s to mid 60s across northern NY and VT with mid 60s to near 70 for southern VT. Surface high pressure continues to dominate heading into Monday night but brief upper ridging begins to overspread the region. So there is a little more uncertainty with how low the temperatures go on Monday night and consequently the frost potential despite light winds. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... Quiet conditions continue to be favored for Tuesday despite a weak shortwave passage. Model soundings show very dry profiles with the most aggressive only showing a shallow layer moisture around 850mb across portions of the Adirondacks and along the Green Mountain spine along with a little elevated CAPE. Have kept in some token 5- 15% PoPs in these areas for the potential of a popup shower, but overall the day should be dry with temperatures seasonally warm in the low/mid 70s. If any showers do pop, they`ll dissipate after sunset with a dry and mild night on tap as southerly flow increases ahead of our next system. Clear skies in the evening, will give way to increasing clouds after midnight with lows generally in the 40s to locally lower 50s in the Champlain Valley. Wednesday will mark a pattern change across the region as a potent upper level trough and sharp cold front remain on track to dig south from Quebec through the forecast area. Like yesterday, ensemble guidance remains very high for measurable precipitation so once again have gone above blended guidance for PoPs in the likely to low categorical range. Should be a nice wetting rainfall, with a slight chance for some embedded thunder with 0.25-0.5" likely across northern zones, lowering to around 0.20" south. In addition, the latest GFS and NAM show temperatures falling sharply along the boundary from mid-day across northern zones and the afternoon south. Similar to frontal passage this past Tuesday, we`ll likely see high temps mid-morning to midday in the low/mid 60s north to low 70s south, then rapidly fall into the 40s north and 50s south through the evening rush hour. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As the previous forecaster eluded to, big changes in the extended forecast came with the 00Z NWP guidance, and that continued to be the trend with the latest 12Z runs. While surface high pressure is still progged to build in behind the frontal passage Wed/Wed night, the upper level pattern now features a closed circulation at 500mb which centers over the region on Thursday, and meanders around the Northeast through the weekend. This supports more diurnal chances for showers each day, especially Thursday across northern zones, and across the entire region again on the weekend. The coldest day of the period looks like Thursday with highs only in the 50s to maybe 60, and lows in the 30s/40s with areas of frost/freeze possible. Thereafter though, temps will be more seasonal in the upper 60s to mid 70s for highs and 40s for lows. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... Through 00Z Tuesday...A cold front continues to make steady progress across the North Country this evening with a line of showers pushing southward. Some light rain showers cannot be ruled out of KSLK and KRUT between now and 2Z but these showers should have no impact on flight conditions given rain is expected to be light. Winds at this time are light and variable but we will see winds shift to the north/northwest in the wake of the front at around 7-10 knots. Dry air will filter in tomorrow with clear skies in the forecast coupled with light north winds. Outlook... Monday Night: VFR. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. NO SIG WX. Wednesday: Mainly VFR, with areas MVFR possible. Likely SHRA, Slight chance TSRA. Wednesday Night: Mainly MVFR, with areas VFR possible. Chance SHRA. Thursday: Mainly MVFR, with areas VFR possible. Slight chance SHRA. Thursday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Friday: VFR. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...Frost Advisory from 2 AM to 8 AM EDT Monday for VTZ003-004-006- 007-016. NY...Frost Advisory from 2 AM to 8 AM EDT Monday for NYZ027-029>031- 034. && $$ SYNOPSIS...Chai NEAR TERM...Chai/Taber SHORT TERM...Lahiff LONG TERM...Lahiff AVIATION...Clay
Area Forecast Discussion
National Weather Service Columbia SC
1045 PM EDT Sun May 21 2023 .SYNOPSIS... A weak front will stall just to the south of the area later tonight and remain stalled just south of the area through Tuesday keeping chances of showers over the southern half of the forecast area. High pressure and dry weather are expected for Wednesday into next weekend. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Late-evening surface observations depict a west-east oriented boundary across the southern Midlands. While winds are northeasterly on both sides of the boundary, there is a distinct dewpoint gradient, with considerably drier air to the north. Very isolated light showers persist along and south of the boundary late this evening, and expect this to continue potentially into the overnight hours as the boundary sags slowly south. Clearing north of the boundary will allow for greater radiational cooling initially, but lower clouds should redevelop later tonight. Farther south, mostly cloudy skies persist, and ceilings should lower through the night. The difference in cloud cover and dewpoints will result in a gradient in low temperatures, with upper 50s north, and lower to mid 60s south. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... High pressure over New England will extend southwestward into the Midlands early this week. Onshore flow will wedge in cooler than normal air with highs in the mid 70s to around 80 degrees. A stalled frontal boundary will be across central Georgia and coastal South Carolina which is close enough to the southern Midlands and lower CSRA for a chance of showers. This boundary gets pushed offshore on Wednesday as high pressure builds in from the Great Lakes. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... A closed upper level low pressure system over the Northeast U.S. gradually extends its influence later this week and into the Memorial Day weekend. The primary influence should be below normal temperatures with highs around 80 and lows in the 50s. This feature may begin to lift away from The Midlands and CSRA next Sunday which would allow temperatures to warm to near normal for the end of May (highs in the mid 80s and lows in the lower 60s). && .AVIATION /03Z MONDAY THROUGH FRIDAY/... East-west surface dewpoint boundary situated just south of the Midlands taf sites of cae/cub. Drier air north of this boundary will continue to try pushing further off to the south overnight, albeit somewhat slowly. Ceilings will be highly dependent upon which side of the moisture front sites are on. Guidance indicating that cae/cub and even ogb will be on the northern side of the front, and with drier air trying to take over they are showing mainly vfr conditions through the period at those locations. One fly in the ointment is the hrrr and nbm still showing lower mvfr ceilings getting close in the Midlands. Will include at least a scattered clouds around 1200 ft later tonight to hint at that possibility. Further south in the CSRA sites of ags/dnl, airmass will be a little moister through the night. This would seem to indicate a potential for ceiling restrictions for a good portion of the overnight. Guidance remains rather bullish on mvfr or lower after midnight, with ceilings remaining down through 15z Monday morning. A return to vfr then becomes possible as the drier air finally pushes through the CSRA and better mixing begins to scour out the lower clouds. Winds at all sites mainly light and out of the northeast overnight, then increase to between 5 and 10 knots late Monday morning. EXTENDED AVIATION OUTLOOK...Drier air over the area in the extended favors lower chances of rainfall and any restrictions through the period at cae/cub/ogb. Better restriction chances possible in the CSRA sites of ags/dnl due to being closer to higher moisture and rain chances each day. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Charleston SC
1050 PM EDT Sun May 21 2023 .SYNOPSIS... A cold front will stall just to the south through Tuesday as high pressure builds in from the north. High pressure will strengthen over the area mid to late week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Late this evening, KCLX detected a few showers across portions of inland GA and SC. These showers should either push outside the forecast area or gradually dissipate over the next several hours. However, the latest run of the HRRR indicates that at least isolated shower activity may linger into the pre-dawn hours. The updated forecast will adjust PoP timing and placement through the overnight hours. Late tonight, widespread stratus will likely form within the wedge, but stronger 1000mb geostrophic flow should limit a fog threat late tonight. Low temps should dip into the low-mid 60s, with upper 60s/around 70 closer to the coast. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... A cold air damming (CAD) set up looks to form on Monday as high pressure builds into the region from the north and a cold front stalls to the south of the area. Aloft a shortwave trough will ripple across the southeastern states along the southern periphery of a larger scale trough. Even with the building high pressure at the surface there will likely be enough upper level forcing to spur showers and thunderstorms, especially across southeastern GA where there will be an axis of instability and increased PWAT values. Scattered to numerous showers and thunderstorms are possible across southeastern GA with isolated to scattered coverage across southeastern SC. The temperature forecast will be a tad challenging as persistent cloud cover across southeastern GA will likely hinder temperatures, the forecast only has upper 70s. Across southeastern SC cloud cover may not be as persistent with some sunshine peaking through and, in spite of the CAD set up, temperatures are forecast to reach into the low 80s. Overnight lows will dip down into the low 60s far inland with upper 60s to near 70 along the coast. A similar set up is expected on Tuesday, with high pressure building at the surface and another shortwave rippling through the southeastern states. Tuesday will feature a very similar forecast to Monday, with the greater coverage of showers and thunderstorms across southeastern GA and temperatures slightly warmer across southeastern SC. Low temperatures will be a little cooler than Monday night, with low 60s inland and mid to upper 60s along the coastline. High pressure will begin to weaken Wednesday at the surface while aloft the region will be placed under broad troughing aloft. Lacking forcing aloft coverage of showers and thunderstorms will be less than on Monday and Tuesday, with isolated to scattered showers and thunderstorms forecast, mainly along and east of I-95. Temperatures are forecast to reach into the mid to upper 70s across the region. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... There is some discrepancy between the global models regarding the synoptic set up through the long term period. All models depict a surface low forming somewhere in the vicinity of the southeastern coastline, but differ in the intensity and placement of the low. Regardless of the low offshore, high pressure will be the dominant synoptic feature across the local forecast area. Precipitation should be confined to diurnal convection along the afternoon sea breeze. Temperatures will remain fairly consistent, with highs in the upper 70s to low 80s and overnight lows in the upper 50s inland and mid 60s along the coastline. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... Prior to the 0Z TAFs: KCLX detected isolated to scattered showers near the KCHS/KJZI/KSAV terminals. The TAFs will be initialized with a mention of VCSH. The showers are expected to dissipate by mid-evening. The primary concern overnight will be the development of restrictive ceilings. Near term guidance indicates that a ridge of high pressure will develop over the area tonight. The combination of low level moisture and weak forcing should support a deck of stratus across the region. Forecast soundings and MOS indicate that MVFR ceilings will develop at KCHS and KJZI later this evening and may linger until mid-morning on Monday. KSAV should see a greater chance for restrictive ceilings, with a period of IFR ceilings possible from 8-12Z highlighted with a TEMPO. Northeast winds are forecast to develop gusts around 20kts between 15-20Z. Extended Aviation Outlook: Showers and thunderstorms are possible Tuesday afternoon, especially around KSAV. && .MARINE... Tonight: A cold front will slowly nudge south of the area overnight, followed by high pressure wedging across inland areas in its wake. The pressure gradient will increase as this process unfolds, strengthening northerly winds across local water, especially after midnight. Winds could gust up to 15-20 kt across local waters, especially across nearshore South Carolina waters late. Seas will also build upwards to 3-4 ft. Monday through Thursday: High pressure will build across the region through the period, leading to increasing NE flow across the local waters. Wind gusts will approach 25 knots beginning as early as Monday afternoon, increasing to 25 knot gusts Monday night. Seas will also build across all waters, with 6 ft seas encroaching on the Charleston nearshore waters Monday afternoon. Small Craft Advisories will likely be needed for all marine waters, possibly including the Charleston Harbor, beginning Monday afternoon. Not much change in the synoptic set up is expected through the week so the Small Craft Advisories may last through much of the week as winds and seas remain elevated. Rip Currents: Increasing NE winds and building swells will lead to an increased risk of rip currents Monday through Friday. A Moderate Risk of rip currents is in effect Tuesday across all local beaches. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM...CPM LONG TERM...CPM AVIATION...NED MARINE...CPM/DPB
Area Forecast Discussion
National Weather Service Cheyenne WY
432 PM MDT Sun May 21 2023 .SHORT TERM...(This evening through Tuesday night) Issued at 330 PM MDT Sun May 21 2023 The main concern with this portion of the forecast is timing of when the Canadian smoke will disperse. Latest visible imagery was showing the bulk of the thicker smoke in the northeast portion of our forecast area. This is tending to reduce the visibility in northeast Wyoming, but it does not appear as thick as it was a few days ago. The inversion will once again settle over the region tonight due to decent subsidence from the upper level ridge and weak surface high pressure. This will tend to keep the smoke settled over the forecast area again tonight with visibilities ranging from 3-5sm. The good news is that the Canadian and RAP models are showing this smoke dispersing and retreating further north into the northern Plains tomorrow. This seems reasonable considering the smoke tended to disperse today. The smoke should also continue retreating further north on Monday night and Tuesday as the southwest flow starts kicking in west of the I-25 corridor and southerly flow returns to areas east of I-25. Overall, the upper level ridge will continue to keep its grip over the region on Monday and allow for another pleasant day. Cannot rule a few isolated showers over the Snowy and Sierra Madre range and Ferris mountains. The models are keying in on surface low pressure developing over northern Wyoming in response to the closed low moving into the northwest U.S Monday evening. This may induce some gusty winds over Carbon county tomorrow evening, but the remainder of the region will be relatively quiet. Tuesday into Tuesday night the models/ensembles are showing the upper level ridge slowly moving east in response to the upper level closed low in western Canada slowly advancing east. This will allow for some better return flow and moisture advection into the region mainly along and west of the I-25 corridor. We did pull precipitation chances back further west than what the National Blend of Models advertised due to lack of instability east of I-25 and mainly southerly steering flow. However, further west of I-25 we may be looking at more scattered showers and thunderstorms. We will need to keep an eye on the mountains for any convection potential especially with rain on snow. .LONG TERM...(Wednesday through Sunday) Issued at 330 PM MDT Sun May 21 2023 The long term weather pattern continues to remain consistent as an active weather pattern and slightly above average temperatures are forecast. A blocking pattern for weather systems to shift from west to east will occur for the medium range to extended forecast as a upper level trough remains over the Northeast, retrograding to the Great Lakes region. Typically this would mean that the upper level ridge pattern that would be stuck over the Central Plains and Intermountain West would result in dry conditions and above average temperatures for our cwa. However, a favorable weather pattern for the Central Rockies will take shape as a pronounced upper level trough will dig south along the CA coastline. Thus, the upper level "dirty ridge" will be supplanted by continual surges of favorable atmospheric dynamics from the upper level low further upstream along the CA coastline and Four Corners region. The upper level low is progged to remain semi-stationary for a few days. This lines up well with the CPC 6-10 Day and 8-14 Day Outlook for chances of above average precipitation and above average temperatures. A shortwave disturbance will propagate along and ahead of the semi- stationary upper level low off the CA coastline Wednesday toward our cwa. A jet streak of 40-45 knots further upstream should provide enough diffluent flow aloft for convection to initiate by the afternoon hours, likely starting off west of the Laramie Range and propagating to the east. However, shear is not looking particularly fruitful for long-lived convection. Additionally, the 700-500mb lapse rates are displaced from the best moisture PWATs, which will be east of I-25 between 0.5 to 1.2 inches on Wednesday. This is modeled by the GFS and NAM. MUCAPE values upwards of 1000 J/kg could provide enough instability after the convective temperature is achieved for a few strong thunderstorms, but severe weather may not be achieved for Wednesday afternoon and evening. The "x-factor" may be the modeled GFS 0-3km storm relative helicity that will be strongest across the NE Panhandle, should model consistency persist. With the weak steering flow aloft, this should be a good opportunity for rainfall in localized areas. Thursday appears to be the best opportunity for strong to potentially severe thunderstorm activity this week, as long as models continue to show a consistent signal. The LLJ signal, MUCAPE values in excess of 1500-2500 J/kg, EBWD shear of 30-40 kts, steep lapse rates, and SRH values in excess of 100-250 m^2/s^2 for areas east of I-25. This coupled with abundant moisture as PWATs may surge to thresholds of 1 to 1.5 inches. This is well above the 90th percentile for PWATs across the high plains. Heavy rainfall may also accompany this favorable setup for slow-moving thunderstorms on Thursday afternoon and evening. Deterministic model GFS soundings are hinting at SVR to potentially TOR conditions. Will continue to monitor the trends the next couple of days in the event that messaging needs to be done to advertise the potential for strong to severe weather. Friday also looks to be potentially active as the afternoon to evening hours will have similar weather conditions to the previous days. Slow-moving thunderstorms may trend towards the strong to severe category if atmospheric dynamics, instability, surface forcing, and moisture combine east of the Laramie Range. Total QPF values per the GFS between Wednesday and Friday night could total between 0.5 to 2+ inches. We welcome the opportunity to have continued impulses of moisture across the region to assist with the prolonged drought conditions. The weekend is forecast to start off on the active category as daytime opportunities for thunderstorms persists on Saturday. This looks to be the last chance of rainfall, which may be a welcomed relief to those that may be planning to do outdoor activities next weekend. Sunday is anticipated to be mild and dry. Thunderstorms are possible south across CO, but it looks to stay outside of our cwa at this time. Despite the active weather pattern signal for the coming week, the above average temperatures should be a welcomed sight instead of any strong cold front we typically see by Memorial Day weekend. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 430 PM MDT Sun May 21 2023 No major changes for the next 6 hours, with much of the forecast remaining on track. Lowered visibilities are expected to continue, with the current wind direction advecting smoke across the region from fires to the north. Expecting these conditions to continue till winds begin to turn more west to southwesterly, and as a result, should begin to see the skies and visibilities lift. At this time, the smoke will likely not clear over the next 24 hours, with HiRes model guidance not having a decent southwesterly wind shift till late Monday into early Tuesday. Areas of fog will be possible again early tomorrow morning, with temporary LIFR conditions possible. && .FIRE WEATHER... Issued at 330 PM MDT Sun May 21 2023 Very low relative humidities of 20 to 30 percent are expected during the next couple of days in response to the strong upper level ridge. However, wind speeds will be fairly light which will limit any fire spread. The remainder of the week, low level moisture will be on the increase. This combined with moist fuels will limit any critical fire weather threat. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...REC LONG TERM...BW AVIATION...MRD FIRE WEATHER...REC
Area Forecast Discussion
National Weather Service Dodge City KS
547 PM CDT Sun May 21 2023 ...Updated Aviation... .SHORT TERM...(This evening through Monday night) Issued at 109 PM CDT Sun May 21 2023 Water vapor satellite imagery and RAP upper air analysis at 1730Z Sunday depicts a rather nebulous 500-mb pattern, with a lone, weak shortwave trough over the northern plains on the eastern periphery of a weak longwave ridge over the western CONUS. Resulting marginal DNVA over the central plains is keeping the skies mostly clear over southwest KS, save for a thin layer of cirrus which will likely shave a few degrees off the afternoon highs today. At the surface, the MSLP pattern is similarly ill- defined, with a weak lee trough in eastern CO supporting 10-20 mph upslope southeasterly winds. Accounting for the somewhat limited solar insolation and the lack of appreciable WAA, afternoon highs will be near or just below normal, maxing out in the upper 70s to low 80s. Short range guidance/HREF both suggest the aforementioned weak upslope flow will allow for at least some moisture advection, and eventually support afternoon thunderstorm development across the higher terrain of southeast CO and adjacent northeast NM. In fact, recent visible satellite imagery shows the beginnings of a cumulus field over this area, suggesting thunderstorm initiation could occur within the next couple hours. Once thunderstorms initiate, convection will expand eastward in coverage, however the degree to which these storms reach into the DDC CWA is still in question given the weak steering flow. Current thinking is thunderstorms will at least reach the US-83 corridor before a stabilizing boundary layer chokes updrafts of CAPE after sunset. Severe weather is not currently expected as bulk shear will remain weak (<25 kts), but 500-1000 J/Kg of CAPE will exist across the western zones and could support brief, marginally severe hail within the strongest storms. Showers may linger into the morning Monday as CAMs hint at a weak MCV developing from the previous night`s convection just south of our area, which would indeed support a localized area of increased convergence that could sustain enough ascent for precipitation, but pinpointing where these showers will be is a fool`s errand. Regardless, overcast skies will be maintained as a result of the MCV, leading to a slightly cooler afternoon Monday with highs in the low 70s. Renewed thunderstorm development is possible Monday afternoon based on HREF guidance, however low confidence in spatiotemporal details significantly limits predictability. .LONG TERM...(Tuesday through Sunday) Issued at 218 PM CDT Sun May 21 2023 Key messages: several days of showers and thunderstorms appear possible through the week, with little to no severe threat. Temperatures will stay at or just below normal. Medium range ensemble guidance indicates upper level ridging will be maintained over southwest KS through the long term period, with deepening troughs to the west and east of the ridge as we get further into the week. These features will allow surface troughing in the lee of the Rockies to continue as well, supporting nearly constant moisture advection from the southern plains into our area via southeasterly winds. As a result, showers and thunderstorms will be possible every day during the long term period, which is reflected in the GFS/ECMWF ensemble members of which all show at least some QPF across the area. Better yet, the weak upper level flow should remove any widespread severe threat entirely, with only brief, isolated severe events possible. Given this very wet pattern, high temperatures will likely stay in the 70s to low 80s throughout the period as well under abundant cloud cover. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 545 PM CDT Sun May 21 2023 Showers and thunderstorms are developing west of GCK and LBL and will have VCTS for those areas from after 00Z through 12Z. Storms will move east and could affect the DDC terminal around 04-15Z and the HYS terminal from 08Z-18Z. Main threat with the storms could be some brief heavy rains that would lower visibility but no severe weather is expected. Outside of the storms the flight categories should stay mainly VFR but could get close to MVFR flight category for Monday morning. && .PRELIMINARY POINT TEMPS/POPS... DDC 55 73 55 74 / 30 50 50 30 GCK 55 71 55 72 / 50 40 30 20 EHA 53 76 55 76 / 60 40 30 20 LBL 55 75 55 74 / 50 40 40 20 HYS 55 73 55 77 / 30 40 40 40 P28 55 76 58 75 / 20 50 50 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Springer LONG TERM...Springer AVIATION...Tatro
Area Forecast Discussion
National Weather Service Des Moines IA
639 PM CDT Sun May 21 2023 ...Updated for the 00z Aviation Discussion... .DISCUSSION.../Tonight through Sunday/ Issued at 230 PM CDT Sun May 21 2023 Key messaging highlights: * Continued warm temperatures through the period * Mainly dry with only infrequent token slight chances until possibly late next weekend There is little change from previous expectations with a fairly inactive period through at least the end of the week. Although there is a compact PV anomaly across SD this afternoon, and a minor ribbon of theta-e advection ahead into the Siouxland area, it will be insufficient for much beyond patchy mid clouds with moisture still lacking. A subtle NE upper wave, along with broad, weak southern stream lift into steep mid/high level lapse rates will also continue to spread cirrus/cirrocumulus into IA tonight and early Monday. The GFS and NSSL WRF are also hinting at very weak convection tomorrow afternoon, but the forecast will be left dry until guidance consensus increases or trends suggest otherwise. Some smoke aloft may also increase into Iowa over the next two days, especially north. Confidence isn`t the greatest however as the extended 15Z RAP appears to have over initialized smoke and any southern trajectories across MO Going into Tue and Wed, central CONUS ridging will continue to expand leaving IA in very weak flow through the column with <=15kts of wind through 25,000ft at times. The GFS, NAM and CMC all hint at unorganized weak convection Wed afternoon in steep low level lapse rates, so will keep slight chances central and south, but if any occur they should fade quickly with the loss of heating. This will be followed by a backdoor cool front, with some depth, that is driven by the passage of a northern/eastern Great Lakes upper trough. After a few days with highs in the 80s, this will briefly drop temps back several degrees but still stay above normal, and also reinforce what continues to be a seasonally dry airmass. 40s dewpoints (or less) will be more common than 50s through the end of the week. The pattern may eventually start to break down later in the weekend as weak southwest flow short waves attempt to chip away at the upper ridge, possibly starting a return of moisture to some depth, especially to the west. The flow will remain weak however so the severe potential will remain low with anything that could develop. && .AVIATION.../For the 00Z TAFS through 00Z Monday evening/ Issued at 637 PM CDT Sun May 21 2023 VFR conditions to prevail through the period with scattered cumulus probable in the daytime tomorrow along with light southeast winds. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...Small AVIATION...Jimenez
Area Forecast Discussion
National Weather Service Quad Cities IA IL
606 PM CDT Sun May 21 2023 ...00Z AVIATION UPDATE... .SYNOPSIS... Issued at 210 PM CDT Sun May 21 2023 Beautiful late May weather occurring today, with surface high overhead bringing plenty of sunshine, comfortable humidity, and temperatures in the 70s. GOES visible satellite loops show some high clouds moving over central IA and some smoke over the Dakotas from Canadian wildfires. A shortwave was accompanying the smoke over the northern Great Plains. && .SHORT TERM...(This evening through Monday) Issued at 210 PM CDT Sun May 21 2023 Key Message: 1. Dry conditions continue, with seasonable temperatures tonight. Another pleasant day Monday to start the work week, with temperatures a few degrees warmer than today. Tonight...Surface high to slide off to the east with weak return flow developing overnight. This will keep lows several degrees warmer than in previous days only dropping into the lower 50s. Another great night to keep the windows open. Monday...mostly sunny skies, light south wind, and low dewpoints will boost afternoon temps into the lower 80s. Some wildfire smoke may be getting close to the CWA late in the day across northern IA and southern MN per latest RAP run of vertically integrated smoke. No near surface smoke is anticipated. .LONG TERM...(Monday night through Sunday) Issued at 210 PM CDT Sun May 21 2023 Key Message: 1. Above normal temperatures, although not as warm as in recent model runs, and dry conditions will be seen through the rest of the work week and into the holiday weekend. Monday night-Tuesday night...building upper level high in the central Plains will bring continued dry conditions and above normal temperatures. Dry soils and dry surface conditions will bring large diurnal temperature swings as much as 28 degrees from Monday night lows in the middle 50s to Tuesday highs in the low 80s. Wednesday-Sunday...A backdoor cold front will push through the CWA from northeast to southwest during the day on Wednesday. Forecast soundings and dry 1000-500mb RH layer progs suggest only an increase in clouds with the fropa and have kept the forecast dry. The speed and timing of the front will be key to highs on Wednesday, with northern IL favored for the cooler readings near 70 degrees to the lower 80s in southeast IA, northeast MO, and west central IL. A faster movement of the front may bring somewhat cooler temperatures closer to the Quad Cities. The NBM while still on the higher end of model guidance has started trending cooler through the period and 90+ degree readings now appear unlikely through the holiday weekend. The coolest timeframe through the extended will be Wednesday night and Thursday when the cooler northeast air, per 6 to 9C 850mb temperatures arrive. Dewpoints will drop into the 30s Wednesday night with lows in the upper 40s to low 50s. Taking a look at the holiday weekend, most model solutions keep us dry through at least Saturday night, with temperatures in the upper 70s and low 80s. The 12z GFS brings a compact shortwave through the area Saturday night and for this reason slight chance PoPs were kept in the forecast. This will change however and chances are this may be delayed even later in the weekend. With the Gulf closed and an upper low off the east, not anticipating much QPF at this juncture if this materializes in later forecasts. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 606 PM CDT Sun May 21 2023 VFR conditions expected throughout the TAF period. Some high-level clouds will linger into the overnight hours tonight. Then, some daytime cumulus clouds are expected to develop by late morning into the afternoon hours, with ceilings generally around 5 kft. Southerly winds of 5 to 10 knots expected Monday. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...Gross SHORT TERM...Gross LONG TERM...Gross AVIATION...Schultz
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
521 PM MDT Sun May 21 2023 ...New AVIATION... .SYNOPSIS... Issued at 1259 PM MDT Sun May 21 2023 Afternoon thunderstorm chances will linger through early next week. Dry air and hot temperatures will build in mid week with winds remaining breezy to light. Hot and dry will persist through the end of the work week, with gusty winds moving in next weekend. && .DISCUSSION... Issued at 1259 PM MDT Sun May 21 2023 Scattered convection has been forming over the Gila Region this afternoon. Storms depict heavy down pours, lightning, small hail, and gusty outflow winds. CAMs have shown more aggression with moving out the surface moisture (saying southwest winds will form near the NM Bootheel and kick it out in the next few hours), however observations relay dewpoints are still in the mid to upper 40s and low 50s for most of the area. Observations have been around 5 to 10 degrees more moist than the HRRR or RAP. With more moisture near the surface, CU have been building over most counties (with the exception of the eastern Otero lowlands). With all this said, confidence with afternoon thunderstorms for most lowland areas is low and mostly clouds and outflows will be seen. Can`t rule out an isolated storm somewhere along the RGV or east but chances will diminish later this evening fairly quickly as the trend is still to dry out. An upper level wave to our west will try to move westerly winds and drier air in every afternoon through Tuesday. Chances for afternoon thunderstorms will be mainly in the higher terrain and east but even those will be isolated as the drier air pushes in more Monday and then Tuesday. Temperatures will be warming a few degrees every day as well with south to southwest winds lightly breezy in the afternoon hours. Mid week an upper level ridge start to take shape with the axis lying over Otero and Hudspeth Counties. Temperatures will warm to above normal (approaching the high 90s in desert lowlands). At the same time an upper level low start to move onshore near central CA. Stronger winds aloft will move over the western areas of the CWA, and create marginally gusty southwest winds. This pattern will stall, making the end of the week fairly unchanged from mid week (hot temperatures, dry air, and breezy afternoon winds). Some chances for a dry line intrusion exist for far east areas but chances remain low. Next weekend the low over CA is forecasted to move eastward and bring gusty southwest winds and dry air over most of the CWA. Returning typical spring to us. && .AVIATION... (00Z TAFS) Issued at 520 PM MDT Sun May 21 2023 Unlike yesterday, convection is slowly beginning to fade. The main threat from the few thunderstorms that are left are the outflow boundaries. It is not likely that any of the main TAF sites will be impacted by one of the outflow boundaries, but Holloman AFB and KALM could see some strong surface wind gusts for the next couple of hours. Otherwise our west winds will continue this evening, with a couple of low end wind gusts. Wind will continue out the west tonight, or will go light and variable. On Monday we will see more west winds with low end wind gusts in the afternoon. Currently we have some mid clouds across the region, as we move more into the evening hours, we will see less and less of them, but we may have an occasionally high ceiling of SCT-BKN250. We will see even less clouds tomorrow, though I can`t rule out a thunderstorm or two, mainly in area mountains. && .FIRE WEATHER... Issued at 1259 PM MDT Sun May 21 2023 Low risk for fire weather conditions expected over the next few days. We are going to be generally dry with minimum relative humidity dropping to below 15% in zone 111 today, then extending into the rest of the lowlands tomorrow. The Sacramento Mountains remain generally above 15%. There will be enough moisture for showers and thunderstorms today across most of the area, except for zone 111. Then convective activity is limited to area mountains on Monday. We will be mostly dry for the rest of the week except in zones 113 and 056, where storms are possible due to the dryline settling in the eastern edge of our region. Winds become from the southwest this afternoon. This will be the prevailing direction through the week keeping the dryline out east. Wind speeds should be around 5 to 15 mph. Ventilation rates will be good to excellent through the week. Next weekend, the passage of an upper system to our north will lead to breezy to windy conditions. This will raise the risk of fire weather conditions to elevated and near critical. && .PRELIMINARY POINT TEMPS/POPS... El Paso 64 94 66 97 / 0 0 0 0 Sierra Blanca 57 86 58 90 / 10 20 10 0 Las Cruces 59 92 60 95 / 10 0 0 0 Alamogordo 56 87 58 90 / 30 10 0 0 Cloudcroft 44 63 46 66 / 30 10 0 0 Truth or Consequences 56 87 59 89 / 10 10 0 0 Silver City 53 80 55 82 / 10 10 0 0 Deming 55 90 56 92 / 10 0 0 0 Lordsburg 55 88 56 89 / 0 0 0 0 West El Paso Metro 63 90 65 93 / 0 0 0 0 Dell City 55 91 56 95 / 10 10 0 0 Fort Hancock 58 93 60 96 / 10 10 0 0 Loma Linda 58 84 60 86 / 10 10 0 0 Fabens 60 92 62 94 / 10 0 0 0 Santa Teresa 58 88 59 92 / 0 0 0 0 White Sands HQ 63 89 65 92 / 10 10 10 0 Jornada Range 55 87 56 90 / 10 10 10 0 Hatch 56 88 57 92 / 10 10 0 0 Columbus 59 90 61 92 / 0 0 0 0 Orogrande 56 88 58 91 / 10 10 0 0 Mayhill 47 76 49 79 / 20 10 0 0 Mescalero 46 75 48 78 / 40 10 10 0 Timberon 45 74 48 77 / 10 10 0 0 Winston 48 76 49 79 / 20 20 0 0 Hillsboro 53 85 55 88 / 10 10 0 0 Spaceport 54 86 55 89 / 10 10 10 0 Lake Roberts 47 81 49 83 / 10 10 0 0 Hurley 52 86 53 89 / 10 10 0 0 Cliff 45 88 45 90 / 10 10 0 0 Mule Creek 52 83 53 85 / 10 10 0 0 Faywood 55 84 55 86 / 10 10 0 0 Animas 55 88 55 90 / 0 0 0 0 Hachita 56 89 56 91 / 0 0 0 0 Antelope Wells 55 88 56 90 / 0 0 0 0 Cloverdale 58 83 56 84 / 0 0 0 0 && .EPZ WATCHES/WARNINGS/ADVISORIES... TX...None. NM...None. && $$ SHORT TERM...99 LONG TERM....99 AVIATION...15-Brice
National Weather Service Sioux Falls SD
1022 PM CDT Sun May 21 2023 .SHORT TERM...(This Evening through Monday Afternoon) Issued at 230 PM CDT Sun May 21 2023 KEY MESSAGES: 1. Spotty high-based showers, perhaps an isolated storm, possible this evening. 2. Canadian wildfire smoke will continue to impact the area early this week, mostly aloft, but could see minor visibility restrictions and air quality issues. 3. Mostly dry through the week, but upcoming Memorial Day weekend could be more unsettled at times. -------------------------------- Compact wave sliding into southeast SD this afternoon is clearly visible on water vapor imagery, as well as some visible imagery in which the spin is evident in the smoke layer aloft. As of early afternoon, starting to see scattered cumulus develop from west of Yankton into north central Nebraska near weak convergence boundary. Will watch this area extending northeast toward KMHE-KBKX for spotty showers, perhaps a few storms given some weak instability in the area from mid-late afternoon into this evening. Forecast soundings show fairly narrow CAPE profiles, with a deep dry layer below 750mb cloud layer, so not sure how much precip will be realized at the surface. However, the dry layer could locally enhance gusty winds near any virga and/or showers. Similar setup in our extreme western counties for Monday afternoon, minus the added weak lift from the compact wave. Will add sprinkles to the area for now, and let later shifts evaluate further after we see how today pans out. Aside from these minor precip chances, the main story will be the return of some thicker smoke aloft. While not apparent on midday satellite imagery, we have seen the milky white sky here in Sioux Falls most of today, with thicker smoke which is more easily seen on satellite poised off to our west. This is handled well by latest RAP smoke model, which slowly expands the thicker smoke aloft back over our forecast area overnight into Monday. With continued southerly flow and little change in the low level thermal profile, high temps should end up close to today`s readings in the upper 70s-lower 80s. As far as the lower levels, the weak low level boundary near our western CWA should keep the more impactful near surface smoke west of the forecast area, though cannot rule out some minor haziness in our far west near the convergence axis. At this point, confidence is not high enough to include in the forecast. .LONG TERM...(Monday Evening through Sunday) Issued at 230 PM CDT Sun May 21 2023 The midweek period Tuesday-Thursday will feature a broad upper level ridge across the nation`s midsection. Northeast to eastern parts of the forecast area may be feel a subtle influence from a back-door cold front, pushing south through the Mississippi and Ohio River Valleys Wednesday into Thursday. Precipitation chances with this feature seem to largely remain east of our area, but we could see cooler temps in our MN/IA counties, depending on how far west the boundary progresses. The upper ridge should largely keep the area dry. However, as the ridge axis begins to shift east on Thursday, weak waves lifting through the western periphery of the ridge could bring a few showers or storms to our western counties Thursday afternoon/night. Models diverge on how quickly to break down the upper ridge as we head into the upcoming Memorial Day weekend, but there is general agreement that Friday-Sunday will become more unsettled, with periodic chances for showers and storms. Mid-upper level flow remains rather weak, lending to weak deep layer shear. So while instability may support scattered storm development that could impact outdoor plans, the potential for organized severe storms is low. As far as temperatures, broad consensus keeps readings above late May normals throughout the period, so current trends are pointing to a warm and muggy holiday weekend befitting the unofficial start of Summer. && .AVIATION...(For the 06Z TAFS through 06Z Monday Night) Issued at 1020 PM CDT Sun May 21 2023 VFR conditions persist overnight. Scattered mid-lvl clouds will remain in place into Monday, along with a thick high level smoke layer. We`re seeing very isolated visibility reductions late this evening due to smoke/haze, but visibility less than 6 mile should remain very isolated. With a bit of lift lingering overnight and mid-lvl ACCAS, an isolated shower is possible towards daybreak, but too limited in coverage to mention. A diurnal cloud field will redevelop by mid-day Monday as winds stay southerly. Thick smoke aloft will remain. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ SHORT TERM...JH LONG TERM...JH AVIATION...Dux
For this long-term forecast discussion, an active weather pattern is
expected to set-up across the High Plains beginning Wednesday and
persisting through the end of the week. Given that this is May, several days of severe thunderstorms can be anticipated as the shortwaves eject over the Plains and a persistent dryline remains fairly stationary along and west of the Colorado border. We`ll go through the set-up day by day as each day has subtle differences that will lead to changes into the anticipated threats/impacts. First, let`s talk about the overall upper level pattern. Beginning with Wednesday, the High Plains will be situated under a ridge of high pressure. However, a trough of low pressure will begin deepening over the western United States. As this happens throughout the week, it should begin to progress slowly, very slowly, towards the Great Plains. The upper level jets will amplify, and this should be favorable for the development and deepening of a surface trough of low pressure in lee of the Rockies. This low pressure system will serve to hold the dryline back further west, preventing it from surging east out of the region. In addition, persistent southeast winds will continue to tap a large reserve of warm, moist air moving northwest from the Gulf of Mexico. All of this being said, there are many factors favoring an active time period from mid-week and into the weekend which could lead to several days of severe thunderstorms and heavy rainfall. On Wednesday, current projections are that the dryline will be somewhere in eastern Colorado, which would open up the entire forecast area to the potential for strong to severe storms. Guidance does suggest that widespread cloud cover is possible due to the flow of moisture into the region, which may be problematic for the instability ingredient for this event. In fact, that does show up in the forecast SBCape with only 500-1000 j/kg forecast in most of the warm sector, except along the dryline where breaks in the clouds may lead to readings approaching 1500 j/kg. The impact of cloud cover is also visible in the projected lapse rates, which are in the 5-7 C/km range in most of the warm sector save immediately along the dryline where readings may reach 8 C/km. For Wednesday, the wind shear parameters can be described as poor for most of the area, although portions of east central and southeast Colorado may see 0-6 km bulk shear values of around 30 kts. Elsewhere across the NWS Goodland service area, 0-6 km bulk shear of 20 to maybe 25 kts is anticipated. The same story is true for helicity parameters. Finally, precipitable water values should climb into the 1.00-1.00 inch range, which is approaching the 90th percentile for this time of year. In the end, it seems there is enough support for severe thunderstorms to occur on Wednesday although any shortwave trough initiating these storms will be weak/subtle. Could see some organized severe storms, and perhaps supercells across eastern Colorado. Heavy rainfall would also be possible, especially since storm motion isn`t terribly high and some areas have received plentiful heavy rainfall recently. On Thursday, the setup is a little more concerning, mainly in terms of the instability and shear parameters as the general upper level and surface setups remain fairly unchanged. For instability, SBCape climbs to a concerning 1500-2500 j/kg and lapse rates of 7-8.5 C/km along the dryline. 0-6 km bulk shear of 35-40 kts and 0-3 km helicity of 150-200 m2/s2 is also concerning. With storms firing on a north to south oriented dryline and moving southeast, it`s possible scattered supercells capable of all modes of severe weather occur. In addition, pwats of 1-1.10 inches again, paired with storm motions of 10-15 knots, will be a prime setup for heavy rainfall and potential flash flooding. Thursday will be a day to keep a close eye on for a possible outbreak of severe storms. For Friday, a very similar setup to Thursday is anticipated. The one main difference seems to be a weakness in the wind fields at the mid- levels, which reduces the available wind shear for organized severe weather. That being said, severe storms and heavy rainfall will certainly be possible once again. One other concern leading to some uncertainty with this potential event is that with more widespread severe weather possible on Thursday, I wonder how impacted the environment will be on Friday from the previous day`s storms. This will be something to watch as in years of experience, it seems difficult to get multiple significant days of severe weather in a row unless there is a substantial cut-off low pressure system causing it. With weak upper level support for these events, it is possible that Friday turns out to be a lower-end day but not a non- zero one. On Saturday, guidance is differing on the upper level pattern as some model members are suggesting a stronger, negatively-tilted shortwave trough ejecting over the High Plains. However, some members suggest this shortwave moves through on Sunday instead, leading to some uncertainty on Saturday`s storms. Wind shear still isn`t terribly strong due to weaker mid-level winds, although they are supposed to strengthen some, particularly if a stronger shortwave and wind maxima materializes. Cape and pwats won`t be a problem for the severe weather and heavy rainfall threat. With the dryline remaining along the Colorado border, most of us will once again see a threat for severe storms. Finally, whew, for Sunday, a bit of uncertainty remains due to differing solutions with the negatively-tilted shortwave that is anticipated to move out over the Plains at some point this weekend. It does appear the surface low begins to meander east, and some solutions depict a cold front sagging south into the region. This uncertainty in surface features will have drastic impacts on the potential severe weather setup on Sunday. For now, I won`t dive into the details...the key message would be there remains potential for strong/severe storms and heavy rainfall going into the end of the holiday weekend. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 504 PM MDT Sun May 21 2023 Both terminals will be impacted with MVFR visibility 3-6sm in patchy smoke. KGLD will see VCTS from 00z-02z. Ceilings OVC009-011 from 12z-16z Monday. Winds for KGLD, south around 10-15kts through 12z Monday then light/variable. By 16z, southeast 5-10kts. Winds for KMCK, light/variable through 16z Monday, then southeast around 10kts. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...076 LONG TERM...RRH AVIATION...JN
Area Forecast Discussion
National Weather Service Grand Rapids MI
753 PM EDT Sun May 21 2023 LATEST UPDATE... Aviation .SHORT TERM...(This evening through Monday night) Issued at 255 PM EDT Sun May 21 2023 -- Dry tonight, few sprinkles possible Mon -- GOES visible imagery shows extensive upper-level smoke continuing to stream into the region, originating from ongoing wildfires in the western provinces of Canada. RAP guidance has handled the evolution of this smoke well, and suggests that appreciable smoke concentrations aloft will remain over much of Lower MI at least through Tue, but with a sharp southern edge. Given relatively modest surface smoke concentrations, smoke impacts will be mainly optical/radiative, yielding a milky sky and marginally suppressed temps during the daytime, but with no significant effect on overnight temps (smoke is essentially transparent in most of the IR spectrum). A diffuse surface high currently over the mid MS Valley will shift eastward tonight and weaken. Meanwhile, a stronger high centered over northern Ontario will build into southwestern Quebec overnight. As this occurs, a surface cold front over the northern Great Lakes will advance southward, then become quasi-stationary over Lower MI on Mon. Modest low-level convergence along this weakening front, combined with a subtle increase in boundary-layer moisture (surface dewpoints likely reaching the low/mid 40s F into central Lower MI), may support a few sprinkles beneath any deeper cumulus clouds on Mon, mainly over the northern/eastern forecast area. However, RAP forecast profiles exhibit fairly high LCLs atop a dry, well-mixed subcloud boundary layer, suggesting that evaporation/virga will be considerable beneath any precipitating clouds. .LONG TERM...(Tuesday through Sunday) Issued at 255 PM EDT Sun May 21 2023 We continue to look at a mostly dry forecast into next weekend, with just a couple of small chances for light rain around Wednesday and next Sunday. The upper air pattern through the long term will be characterized as an omega block with long wave troughing over both of the CONUS coasts, with an upper ridge centered over the Plains. We will downstream of the upper ridge, allowing for mainly dry weather under strong subsidence. There will be a few weak short waves that will spill over the ridge, and try to clip the area. A ridge of high pressure at the sfc will continue to foster warm and dry conditions for Tuesday. 850 mb temps under max heating will allow for temps to sneak up around the 80 mark away from Lake Michigan. Then on Wednesday, a fairly strong upper wave will be spilling over the upper ridge, and across Ontario and over the NE U.S.. This wave will drag a backdoor cold front through the area on Wednesday. It is a fairly strong front with 80s ahead of it, and 60s behind it with dew points in the 20s. The problems with getting any meaningful rain from it are the upper energy staying NE of the area, and no moisture in place or feeding in ahead of it. There may be a few sprinkles or a light shower, but that would be about it. Much cooler air will filter in over the area behind the front starting late Wednesday, and continuing into Thursday. The dry air behind the front mentioned above will clear things out nicely for the area, even with another short wave coming through. This will continue through at least Friday and Saturday of the upcoming holiday weekend. The only problem there may be would be some possible frost Wednesday night across interior portions of Central Lower. Some uncertainty does appear in the forecast for next Sunday, whether it would stay dry, or maybe a chance of rain might arrive. Multiple model solutions and their ensembles have shown the upper low complex over the East Coast trying to retrograde back to the west a bit. Depending on how much it would, it could come back far enough west to bring some rain chances in starting next Sunday. The ridge to our west will be trying to hold tight. These scenarios are tough to pin down where exactly the upper lows will rotate. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 753 PM EDT Sun May 21 2023 VFR conditions are in place across the area this evening as high pressure is situated over the Great Lakes region. Skies are mainly clear outside of a few cumulus clouds that will quickly dissipate this evening. Some scattered cumulus is possible again on Monday, with bases up around 5,000 feet. Plenty of smoke continues to affect the Great Lakes region from fires that are distant up in Canada for the most part. This smoke will remain aloft based on model data and not affect surface visibility. There is a threat of some light radiation fog tonight at the southern TAF sites along I-94 with the best chances between 08z and 12z. Light winds will be the rule the next 24 hours, under 10 knots. && .MARINE... Issued at 255 PM EDT Sun May 21 2023 Nearshore winds will likely be dominated by diurnal lake-breeze / land-breeze circulations into Tue, characterized by weak onshore flow developing in the afternoons (as is occuring now), then weak offshore flow developing overnight. Confidence is high that winds/waves will remain below SCA criteria through Tue. A weakening cold front will reach northern Lake Michigan later this evening, then become stationary on Mon. A somewhat stronger cold front will advance southward over the lake on Tue night and Wed. Precip along this front will likely be spotty/limited, but north to northeast winds will develop/increase behind this front. Winds may reach SCA criteria (22+ kts) from Tue night into Wed, but wave development will likely be limited by the expected offshore flow in most areas. The exception may be the vicinity of Big and Little Sable Points on Wed afternoon, where shore-parallel flow may yield relatively higher waves. && .FIRE WEATHER... Issued at 255 PM EDT Sun May 21 2023 We are looking at Fire Danger remaining elevated through this week, and likely becoming more of a concern over time. Fire danger this afternoon ranges from moderate across the SE portion of the area where a wetting rain was experienced on Friday, to very high across Central Lower where there has been very little to no rain for a while. Also, Central Lower is where the Jack Pine Trees are found, and are a volatile fuel at this point in the green up process. Further south, green up has progressed enough that the fire danger should not be a problem. The only rain chances this week really look to be on Wednesday with a stronger cold front dropping down through the area. This rain is not expected to be anything that would put a dent in the fire danger with amounts less than a tenth of an inch or less. The silver lining in the forecast is that it is likely that we do not see all three ingredients come together for Red Flag conditions this week. The days it is warm and dry there looks to be lighter winds. The days it is windy and dry like Wednesday and Thursday, temperatures will be lower. This is not to say that the land management agencies will not request a headline, but the meteorological conditions do not look to come together. We will continue to monitor the potential until we can get appreciable rainfall to lower the danger. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ SHORT TERM...Kenyon LONG TERM...NJJ AVIATION...Duke FIRE WEATHER...NJJ MARINE...Kenyon
Area Forecast Discussion
National Weather Service Northern Indiana
1201 AM EDT Mon May 22 2023 .SYNOPSIS... Issued at 203 PM EDT Sun May 21 2023 High pressure anchors across the Great Lakes through next week as dry weather persists. Warm weather starts the workweek with highs reaching into the upper 70s to lower 80s before trending briefly cooler Thursday through Friday. Memorial Day weekend will be warm and dry. && .SHORT TERM...(Tonight through Tuesday) Issued at 203 PM EDT Sun May 21 2023 Broad sfc ridge will anchor across the Great Lakes this period, providing continued dry and mild weather as upper ridge begins to build further in time. && .LONG TERM...(Wednesday through Saturday) Issued at 203 PM EDT Sun May 21 2023 Backdoor cold front will drop through the area Tue night and will cool temps some Wed-Fri before warming renews upstream of blocky east coast centered upper troughing. Lots of model uncertainty toward next weekend with where this slow moving feature sets up however degree of upper ridging wwd of this sys looks to make for a very warm Memorial Day. && .AVIATION...(For the 06Z TAFS through 06Z Monday Night) Issued at 1151 PM EDT Sun May 21 2023 A stagnant pattern will persist with weak high pressure over the area. Winds will remain light. Patchy shallow ground fog is likely by daybreak, but it is not expected to be operationally significant, so have kept it out of the TAFs. Any fog will mix out quickly after sunrise. Smoke aloft from upstream fires has temporarily cleared. The latest HRRR keeps the smoke out for now. Otherwise, a very dry environmental sounding should not support any clouds except for possibly some high based afternoon cumulus as was the case Sunday. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...T SHORT TERM...T LONG TERM...T AVIATION...Skipper Visit us at Follow us on Facebook...Twitter...and YouTube at:
Area Forecast Discussion
National Weather Service Morristown TN
911 PM EDT Sun May 21 2023 ...New UPDATE... .UPDATE... Issued at 908 PM EDT Sun May 21 2023 Still an isolated shower or two across SW NC, and these should dissipate later this evening. The forecast generally looks to be in decent shape, with clouds expected to increase from S to N overnight. Will tweak temps and dew points with this update. && .SHORT TERM... (This evening through Monday) Issued at 306 PM EDT Sun May 21 2023 Key Message: 1. Slight chance for an afternoon shower or thunderstorm possible Monday afternoon in the southern Tennessee valley. Discussion: What a nice day! Went outside to take a few looks, and yes skies are still hazy and not as blue as they should be for such a clear day. Only clouds currently are building along the mountains, which we cannot see from our office due to said haze. Haze is due to the ongoing Alberta Canada fires, which have continued to send massive plumes of smoke into the US. Fortunately the smoke will remain elevated, and should not pose an air quality issue. High clouds from a southern system will stream in overnight and lead to mostly cloudy skies by sunrise for the southern two thirds of the valley. Best chance for some patchy fog overnight will be the Tri Cities area and north where clearer skies will remain and winds will drop to calm for a longer period of time overnight. Tomorrow Dry weather will continue until tomorrow afternoon, when a few people will win the lottery for some rain. A weak 500 mb shortwave will be passing south of Tennessee. With just enough forcing from the shortwave, we could see an isolated shower/thunderstorm or two Monday afternoon into early evening before dissipation as the day loses its heat. HRRR was the most aggressive out of both CAMs and the global models with coverage. CAPE values are only around 300 or so, so not expecting any significant fireworks. && .LONG TERM... (Monday night through next Sunday) Issued at 306 PM EDT Sun May 21 2023 Key Messages: 1. Near normal temps through the extended. 2. Mostly dry for the long term forecast, with a few scattered chances for precip. Discussion: Extended forecast is pretty benign overall. Tuesday will be dry for the majority of the area, with some slight chances for diurnally driven afternoon showers and possibly a few rumbles of thunder in the southern valley and higher terrain. Northeasterly/easterly 850 flow on Wednesday could produce some downsloping wind that could lead to a dip in Td and subsequent RH values Wednesday afternoon in the Valley. A low over southern Ontario will dig an upper trough south over the southern Appalachians towards the middle and end of the week. As this trough dips into the mid-Atlantic and southern appalachians, it pushes a cold front to approach TN from the north on Thursday, leading to a slight uptick in PoPs in northeast TN and the East TN mountains. Confidence in the synoptic setup remains iffy, this leans us towards an omega block pattern for the weekend with ridging over the central US and a trough over both the east and west coast. && .AVIATION... (00Z TAFS) Issued at 637 PM EDT Sun May 21 2023 Clouds will increase, and there is a very low chance of a shower during the day at CHA but probability is too low to include for now. VFR conditions are expected for the period all sites. Winds will generally be light. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 60 82 61 81 / 0 30 20 20 Knoxville McGhee Tyson Airport, TN 56 82 59 81 / 0 10 10 10 Oak Ridge, TN 56 83 60 81 / 0 10 0 10 Tri Cities Airport, TN 50 80 56 78 / 0 0 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...Wellington LONG TERM....BW AVIATION...
Area Forecast Discussion
National Weather Service Mount Holly NJ
848 PM EDT Sun May 21 2023 .SYNOPSIS... Canadian high pressure will build southward down the East Coast through Tuesday, resulting in mainly quiet weather. A cold front will push in from the northwest late Wednesday, followed by another area of high pressure and a somewhat cooler and drier airmass for Thursday and Friday. && .NEAR TERM /THROUGH MONDAY/... High pressure continues to build over the region with deep subsidence evident on the WV satellite. Some persistent strato- cumulus developed late Sunday morning through the afternoon, resulting in more clouds than sun for much of our region. The old CU- rule (model low- level moisture/stability parameter) highlighted these clouds fairly well based on RAP guidance. With the loss of daytime heating, increased stability and lowering mixing heights, skies are clearing and northwest breezes have relaxed. Expect winds to become calm overnight with lows dropping into the mid to low 50s. Fair weather continues for Monday as high pressure sits over the region. Ye olde `cu rule`, along with forecast soundings and modeled sky cover suggest that cumulus and stratocumulus will once again develop midday Monday and possibly last through the evening, particularly northwest of I-95. There is a 15 to 30 percent chance for showers and even a slight chance for a thunderstorm around the Poconos Monday afternoon as a cold front moves south. Would not rule out spotty showers as far south as the Lehigh Valley and into parts of northern NJ as well. Any showers that develop are not anticipated to impact central, southern NJ, SEPA, or DelMarVa. Highs tomorrow are expected to be in the mid to upper 70s. However, areas closer to the coast will stay in the 60s with a notable onshore breeze. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... High pressure over New England Monday night will drift offshore by Wednesday morning. This set up will bring mainly clear skies with continuing onshore winds. An upper level trough and associated surface cold front will pass through upstate New York Wednesday and through our region Wednesday night. This will result in widely scattered showers and thunderstorms mainly for areas north of the urban corridor Wednesday evening. && .LONG TERM /THURSDAY THROUGH SUNDAY/... Following the frontal passage, Thursday and Friday should feature sunshine with seasonable temperatures dominated by surface high pressure. Models continue to suggest an upper level low will form over the northeastern United States Friday and remain over the area through Sunday. Meanwhile, rain associated with a system in the southeastern United States may become absorbed by the upper low, bringing clouds and rain northward for the first half of the holiday weekend. It is still uncertain if much of the rain moving northward will remain offshore or will impact areas further inland. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight (00Z through 12Z)...VFR/SKC. NW to N winds gusting to 18 kt in some spots until 00-02Z, but otherwise becoming 5 kt or less overnight, and tending to veer to NE. High confidence. Outlook... Monday...VFR. Some 040-080 ceilings develop in the afternoon mainly NW of I-95, with some brief showers possible from about ABE northward. East to northeast winds 4-8 kt, but 10-15 kt near the coast. Tuesday through Friday...VFR. Isolated showers late Wednesday in the Poconos and Lehigh Valley into northwestern New Jersey. && .MARINE... Mainly southerly winds around 5 to 10 kt becoming light northerly overnight. Sub-advisory conditions as seas have continued to drop off with a decaying easterly swell. Combined seas mainly in the 2 to 4 ft range into Monday. Outlook... Monday through Tuesday...Winds increasing ENE 10-16 kt with some gusts over 20 kt. Seas may build back to around 5 ft on Tuesday, particularly offshore, which may require a Small Craft Advisory. Wednesday...Winds veer to SE around 10 kt as a cold front approaches Wednesday night. Seas 2 to 4 ft. Thursday and Friday...North to Northeast winds 10-20 kt with gusts possibly around 25 kt at times, and Small Craft Advisories may be needed. Seas 4 to 6 ft. Rip Currents... There is a LOW risk for the development of dangerous and life threatening rip currents for Delaware and New Jersey beaches on Monday. The risk increases to MODERATE on Tuesday for New Jersey beaches. Winds will be from the northeast at 10 to 15 mph on Monday. Breaking waves are expected to be around 1-2 feet with a medium period easterly swell. Winds on Tuesday become more easterly and remain around 10 to 15 mph. Breaking waves are expected to increase to be around 2-3 feet, particularly along the coast of New Jersey. A medium period easterly swell remains as well. Please keep in mind that lifeguards may not be on duty, and ocean temperatures are still quite chilly, mainly in the lower 60s. This makes it especially dangerous to enter the surf. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ SYNOPSIS...Deal/Fitzsimmons NEAR TERM...Dodd/Deal/MPS SHORT TERM...Fitzsimmons/Franklin LONG TERM...Fitzsimmons/Franklin AVIATION...Dodd/Deal/Fitzsimmons/Franklin/MPS MARINE...AKL/Deal/Fitzsimmons/Franklin/MPS