####018004839#### FXUS63 KPAH 040424 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 1124 PM CDT Fri May 3 2024 .KEY MESSAGES... - Warm temperatures continue this weekend and through next week. - Unsettled weather pattern through next week with scattered showers and storms Saturday through Monday, and more widespread storms Monday night through Thursday. - Potential exists for severe thunderstorms and heavy rainfall next week. && .DISCUSSION... Issued at 240 PM CDT Fri May 3 2024 Upper level troughing will remain to our North and West with several disturbances advancing through the region helping to bring scattered showers and storms this weekend and into next week. This afternoon a weak disturbance is moving across the area helping to generate some scattered shower activity. Wind fields aloft are weak, so not expecting much any organization this afternoon and into tonight. The loss of forcing, and nocturnal stabilization should lead to mostly dry conditions tonight. A northern stream disturbance moves across the northern plains Saturday into Sunday. A few weak impulses are progged to move across the region leading to scattered showers and storms within a moist and unstable airmass. Overall, the lack of shear should keep severe potential low, although an isolated strong to severe storm is possible across SEMO Saturday afternoon/evening. Our attention then turns toward a few days of more active weather Sunday into the middle of next week. A more robust shortwave lifts from the southern plains with a weak boundary draped across the Quad State Sunday night into Monday. Better synoptic scale forcing combined with an unstable boundary layer should lead to more widespread showers and storms during this period. Unlike today and Saturday, mid level flow will be slightly stronger as a 30-35 knot mid level jet noses into the area. Deep layer shear approaches 30 knots which may lead to some organized convection, although the current thinking is that these potential storms will be more isolated in nature. The upper levels amplify Monday night into Tuesday as a sharp upper trough digs into the northern plains. Shortwave ridging developing over the region may keep things more isolated Monday into Tuesday morning. Tuesday will be breezy as low level winds increase associated with strong mid/upper level flow. Winds could approach 30 mph during the afternoon. Still need to watch for severe weather potential Tuesday into Thursday associated with a more amplified upper level pattern and a good overlap of shear and instability. Deep layer troughing will develop across the Rockies and move into the plains states. Still some questions on when the greatest time-frame for severe weather but there seems to be an increasing signal on the Wed-Thu time- frame. An area of low pressure develops across OK/TX and lifts northeast into Missouri. Increasing divergent flow aloft will overspread an increasingly moist and unstable airmass with dewpoints likely approaching or exceeding 70 degrees. Increasing southwest flow aloft will translate to increased deep layer shear for organized severe weather. All modes of severe weather appear possible at this time. Later forecasts will be able to fine tune timing of severe weather. Additionally, will also need to keep an eye on flooding concerns with several rounds of convection possible through next week. Drier weather arrives Friday post fropa and with increasing zonal flow aloft. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1116 PM CDT Fri May 3 2024 A little big challenging forecast with dewpoints very near the temperature across the area late this evening. Winds are fairly light under a temperature inversion, which would favor fog formation; however, latest satellite trends are showing more stratus developing under the inversion over portions of SEMO. At this point, have stuck with fog and mention of a scattered low deck in the TAFs, but this may need to be adjusted through the night. Improving conditions are expected after daybreak Saturday with mid to high clouds streaming in from the west and southwest. A scattered shower or storm is possible, but confidence in timing and coverage is low enough to leave out with this update. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Dense Fog Advisory until 9 AM CDT Saturday for ILZ075>077- 080>094. MO...Dense Fog Advisory until 9 AM CDT Saturday for MOZ076-086-087- 100-107>112-114. IN...None. KY...Dense Fog Advisory until 9 AM CDT Saturday for KYZ001>009. && $$ DISCUSSION...AD AVIATION...KC ####018004344#### FXUS64 KMEG 040426 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 1126 PM CDT Fri May 3 2024 ...New AVIATION... .UPDATE... Issued at 915 PM CDT Fri May 3 2024 Main concern overnight is fog development. Clouds are moving off to the NE and some clearing has already occurred across western sections of the Mid-South. Most of the area has seen at least some rain during the last 24 hours and little if any drying occurred today. Dewpoint depressions have already fallen to 1 degree or less over much of the Mid-South. Low temps will crash through the crossover temp as well. The latest HRRR model runs have been indicating at least areas of dense fog as well. Given all this evidence have decided to go ahead and issue a Dense Fog Advisory for the entire Mid-South from 1 am to 9 am Saturday. Also, cut pops for the remainder of the night. && .SYNOPSIS... Issued at 330 PM CDT Fri May 3 2024 Active weather will persist across the Mid-South over the next 7 days or so. Showers and thunderstorms will be possible each day as upper level disturbances move through. There is the potential for organized weather towards the middle of next week as a low pressure system moves into the region. Temperatures will likely remain near normal due to clouds and storms each day. Expect highs around in the lower 80s and lows in the 60s. && .DISCUSSION... (This evening through next Thursday) Issued at 330 PM CDT Fri May 3 2024 A mostly dry day across the Mid-South at this hour. Two decaying MCSs moved into the area this afternoon, but didn't produce much convective activity as previous model guidance suggested. The most active weather is currently near the Alabama and Mississippi stateline, where a cluster of slow-moving strong storms have congealed. Hi-res models continue to struggle with shower and thunderstorm coverage across the region. The latest thinking is that this activity will continue to slowly lift northeast through sundown and taper off after sundown with the loss of daytime heating. Weak southwest flow aloft will persist through early next week. This will allow several weak perturbations to translate through the region. This weather pattern will continue to pose a challenge for nearly all model guidance, as steering flow will be weak and not well resolved. Using a more probabilistic approach is likely the best scenario here, however the 12Z HREF is not showing much in the way of precipitation for Saturday. Nonetheless, went with the NBM, which keeps 40 to 60 PoPs over the Mid-South tomorrow afternoon. Convective coverage looks a bit better on Sunday as a weak cold front and shortwave move into the region. Organized weather appears more likely by the middle of next week, as a large upper low ejects through the Central Plains. Subtle height falls will occur Tuesday night into Wednesday, where a Day 5 Slight Risk has been introduced north of I-40. A better chance of strong to severe storms appears to be next Wednesday into Thursday, where a surface low will track to our northwest. Still a bit early to sort out specific details, as synoptic model guidance still has timing and feature differences. A cold front looks to move through by late week and bring cooler and drier air to the region for next weekend. AC3 && .AVIATION... (06Z TAFS) Issued at 1125 PM CDT Fri May 3 2024 Primary aviation concern in the near term will be the development of lower VIS and CIGS across the airspace, where some locations can expect fog development as visibilities to drop to 1/2 mile or less. Conditions should gradually improve through the late morning hours, returning to VFR conditions by the early afternoon. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...Dense Fog Advisory until 9 AM CDT Saturday for ARZ009-018- 026>028-035-036-048-049-058. MO...Dense Fog Advisory until 9 AM CDT Saturday for MOZ113-115. MS...Dense Fog Advisory until 9 AM CDT Saturday for MSZ001>017- 020>024. TN...Dense Fog Advisory until 9 AM CDT Saturday for TNZ001>004- 019>022-048>055-088>092. && $$ PUBLIC FORECAST...SJM AVIATION...JPR ####018007542#### FXUS66 KLOX 040427 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 927 PM PDT Fri May 3 2024 .SYNOPSIS...03/855 PM. Cooler than normal temperatures will continue through at least the weekend as a weak storm system moves across California. Some light precipitation is expected Saturday afternoon into very early Sunday along with some gusty winds at times, mainly over interior areas. A warming and drying trend will develop next week. && .SHORT TERM (FRI-MON)...03/927 PM. ***UPDATE*** Today low clouds associated with the deep marine layer extended over most coast and valley locations. These clouds were slow to burn off south of Point Conception, lasting into the late afternoon for Los Angeles County, and all-day for Santa Barbara city and much of Ventura County. Temperatures were cooler than yesterday by 2 to 5 degrees, resulting in below normal conditions for all coasts and valleys by about 3 to 7 degrees. Tomorrow the incoming storm system will near the region, resulting in increasing mid to high cloud cover as the day progresses, and temperatures will drop significantly, with the majority of highs in the 60s. Southwest to west winds will be gusty for interior SLO County and Antelope Valley and San Gabriel Mountains of LA County. Wind Advisories will be issued this evening for the aforementioned portions of LA County, starting at noon on Saturday and lasting until 5 AM on Sunday. Gusts of 40-50 mph are expected to be common for these areas. Saturday night, Sundowner wind will impact much of the Santa Barbara south coast, including Santa Barbara city and Montecito. At this time wind gusts may reach 30-45 mph, and wind advisories will likely be needed for this area. More widespread advisory-level winds are likely on Sunday. Light rain is on track to begin for northwestern portions of SLO County Saturday afternoon, spreading south during the evening and overnight. Rain totals continue to look very minimal, with just a few hundredth on a inch expected for Santa Barbara City, and LA/Ventura Counties coasts, valleys, and deserts. However, accumulations of 0.25 inch will be possible over the San Gabriel mountains, and up to 0.50 inch over NW San Luis Obispo County. ***From Previous Discussion*** A late season storm is approaching California today and we're already feeling the effects of it in the form of a deeper and slow clearing marine layer as well as much cooler temperatures. Models have been quite consistent the last several runs indicating high chances for rain north of Pt Conception starting Saturday afternoon. The trajectory of the storm and the primarily westerly low level flow isn't as favorable a pattern for southern areas in terms of rain but most areas should see at least some sprinkles or light showers Saturday night. Ensembles continue to project around a quarter inch northern areas, tapering down to a tenth or less in the south. Most of the precip will be done before sunrise Sunday, so most of Sunday will be dry with plenty of sunshine but still cooler than normal with some breezy and conditions, especially near the coast and in the mountains. Monday will be much warmer as the storm moves into the Plains and onshore flow weakens. .LONG TERM (TUE-FRI)...03/217 PM. The remainder of next week is expected to be fairly quiet with a slow warming trend, mainly inland as California sits between a low pressure system over the Great Basin and high pressure over the eastern Pacific. Coastal area temperatures will be near normal with possibly some increasing marine layer stratus by around mid week. There is potential for more significant warming (again mainly inland) next Friday into next weekend if the ridge over the eastern Pacific shifts east into California as some models are showing. && .AVIATION...04/0054Z. At 0000Z at KLAX, the marine layer was 2400 feet deep. The top of the inversion was at 4600 feet with a temperature of 19 degrees Celsius. Overall, moderate to high confidence in the 00Z TAFs. MVFR CIGS are forecast to arrive at all sites except KPRB, KPMD and KWJF between 03Z-06Z. The CIGs are expected to linger through the period as a storm system approaches the area, with -RA likely after around 21Z north of Point Conception, and after 00Z-06Z further south. There is a 30-40 percent chance that CIGs could lift to VFR at any site between 18Z-00Z Saturday afternoon. KLAX...Moderate confidence in the 00Z TAF. MVFR CIGs are expected by 03Z but the arrival time could be delayed by up to 2 hours. There is a 30 percent chance that CIGs remain at MVFR level between 23Z-03Z. No significant easterly wind component is expected. KBUR...Moderate confidence in the 00Z TAF. For tonight, there is a 30% chance that MVFR CIGs could arrive as early as 03Z. && .MARINE...03/828 PM. For the Outer Waters, moderate to high confidence in current forecast. For tonight, Gale Warnings have been downgraded to Small Craft Advisories (SCA) and will continue into Saturday morning. For Saturday through Wednesday, high confidence in combination of Small Craft Advisory (SCA) level winds and seas with a 40-60% chance of Gale force winds Sunday afternoon through Sunday night, and possibly into Monday, over the southern outer waters from Point Conception to San Nicolas Island. Across all of the outer waters, there will be a 30% chance of Gales Monday night, with winds then gradually decreasing through Wednesday. For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Winds have subsided below SCA levels this evening. Saturday through Wednesday, there is a 60-80% chance of SCA level winds with the strongest winds during the afternoon and evening hours. Additionally, there is a 30-40% chance of Gale force winds Sunday night and Monday, but especiall Monday night. SCA winds are likely to follow Tuesday through Wednesday. For the Inner Waters south of Point Conception, moderate confidence in current forecast. Tonight through Saturday, high confidence in winds and seas remaining below SCA levels. For Saturday night through Sunday night, high confidence in a combination of SCA level winds and seas with a 40-50% chance of Gale force winds Sunday afternoon and Sunday night, especially across western sections. For Monday through Wednesday, there is a 50-60% chance of SCA level winds across the western half of the Santa Barbara Channel with high confidence in winds and seas remaining below SCA levels elsewhere. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory in effect from noon Saturday to 5 AM PDT Sunday for zones 379>383. (See LAXNPWLOX). PZ...Gale Watch in effect from Sunday afternoon through late Sunday night for zones 650-655-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Saturday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 8 AM PDT Saturday for zones 673-676. (See LAXMWWLOX). && $$ PUBLIC...MW/Schoenfeld AVIATION...Smith MARINE...RAT/Smith SYNOPSIS...MW/Smith weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox