####018003884#### FXUS62 KCAE 041700 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 100 PM EDT Sat May 4 2024 .SYNOPSIS... Showers and thunderstorms have moved into the area and will continue through early next week with showers and thunderstorms likely. Dry conditions should prevail for mid- week, with a return of showers and storms possible again by Friday. Expect well above normal temperatures each day. && .NEAR TERM /THROUGH TONIGHT/... Showers and a few thunderstorms have developed this morning across the western Midlands and CSRA with another area currently developing in the eastern Midlands. This is in response to the short wave moving through the region with another short wave moving through the area later today and tonight. Although there is ample instability for thunderstorms the cloud cover is limiting heating keeping much of the convection limited in vertical development and thus more showers than thunderstorms. Rainfall efficiency has been impressive so far with rates between 2 and 2.5 inches per hour and with pwat values ranging from 1.5 to 1.8 inches through tonight expect this to continue. Will be monitoring several areas across the CSRA and western Midlands as up to 2.5 inches of rainfall has already fallen. Will also be monitoring the developing thunderstorms and rainfall rates in the eastern Midlands for any hydro related issues. High temperatures this afternoon will range from the mid 70s in the western Midlands and CSRA to the upper 70s to around 80 in the eastern Midlands. Low temperatures tonight will be in the low to mid 60s. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... High pressure off shore will keep low-level moisture across the area Sunday and Sunday night. Weak upper shortwave will move through the area, and even with limited instability, scattered showers and thunderstorms are expected to develop through the day. Daytime temperatures will be near normal, with highs in the lower 80s, while overnight lows will be in the middle 60s, which is well above normal. && .LONG TERM /MONDAY THROUGH SATURDAY/... Monday into Tuesday will see upper trough passing through the area, with upper ridging then moving in Wednesday into Thursday. A deepening upper trough will then push southward into the region Friday. This pattern generally will bring a period of showers and thunderstorm early in the week, with dry weather then expected during the mid-week timeframe. By Friday, showers and thunderstorms will re-enter the region ahead of the approaching trough. Temperatures are also expected to gradually increase from just above normal on Monday, to well above normal through the end of the week. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... Variable conditions in showers and thunderstorms with restrictions likely for much of the TAF period. Showers and a few thunderstorms have mainly been west of the terminals this morning and are now developing across the entire area. Have update the TAFs to include the developing convective activity through the evening hours. Cigs with the showers and thunderstorms will lower to 1 to 1.5 kft with vsbys lowering to 1 to 2SM as showers have been efficient rain producers with rainfall rates around 2 inches per hour. Convection will diminish early tonight however with high amounts of low level moisture expect stratus and fog to continue through the end of the period. EXTENDED AVIATION OUTLOOK... Fog and stratus possible through at least Monday with abundant low level moisture in place. Showers and thunderstorms with associated restrictions possible Sunday through Tuesday. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$ ####018007640#### FXUS61 KOKX 041701 AFDOKX Area Forecast Discussion National Weather Service New York NY 101 PM EDT Sat May 4 2024 .SYNOPSIS... High pressure remains in place along the New England coast into tonight. A cold front then slowly approaches from the west on Sunday, eventually tracking through the region Monday. The boundary likely stalls to our south Monday afternoon through Wednesday before returning as a warm front late in the week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Minor update to this afternoon temperatures and dewpoints to better reflect current conditions. Otherwise, the forecast remains on track. Amplified ridging aloft remains over the Eastern US today, with surface high pressure in place along the New England coast. This will maintain a persistent onshore flow through the weekend, and lead to cooler than typical temperatures for early May. Meanwhile, a weak area of low pressure associated with a shortwave riding over the ridge passes well to the northwest through the Upper Great Lakes late in the day, sending a slow approaching frontal boundary toward the region. While a spotty shower can't be ruled out this afternoon, mainly in far western portions of the region, the day will be predominantly dry. Expect a fair amount of cloud cover, thickening into this evening as the ridge axis shifts offshore, allowing deeper moisture to advect into the area in the SW flow. This should lead to eastward expansion of shower coverage off to the west that very gradually begins to work in tonight, likely after midnight even for the farthest west locales. With the return flow and cloud cover, temperatures this weekend run up to 10 degrees below normal, with afternoon highs in the low to mid 60s today, falling into the 40s overnight into Sunday AM. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... By Sunday, the shortwave associated with an upper low over Central Canada attempts to break down the ridging over the East Coast, with the surface front draped along the Midwest starting to make progress eastward. Guidance continues to advance this boundary quite slowly, with the fropa perhaps not occurring locally until Monday. Ahead of it, plenty of deep moisture in the column and weak lift should instigate shower activity by the mid morning, at least for the western half of the region, before spreading east by the afternoon. Showers may continue intermittently into Sunday night before tapering west to east. QPF appears light with this activity, generally ranging from a quarter to a half inch. The shortwave energy pushes offshore Monday with the surface boundary stalling to our south and west. Ridging builds once again across the Great Lakes in response to a large upper low over the Northern Plains and Northern Rockies. Latest guidance is less enthused about energy riding under this and interacting with the stalled boundary, which would allow a return of steadier rain chances depending on placement. Trimmed back PoPs Monday night as a result, though still not out of the question a few showers make it into Long Island from the south. After the chilly Sunday in the low to mid 50s for most, temperatures rebound on Monday in SW flow back into the 70s across the interior and areas away from maritime influence. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Tuesday begins with high pressure to our north and a stationary front across the Mid-Atlantic. This front is expected to slowly push north towards us as a warm front through the day. Looks like most of the day will be dry, but still a low threat of showers over roughly the western half of the forecast area - closer to the deeper moisture and lift. A ridge aloft flattens Tuesday night into Wednesday with a surface low tracking east across the northern Great Lakes. The warm front will continue to try to push into the forecast area during this time, however a synoptic onshore flow off of cold waters along with influence from low pressure over the Canadian Maritimes with both serve to hold this front to our south. Chance of showers for this period, and maybe even a rumble of thunder Weds afternoon with elevated instability pushing in from the west. The surface low to our north then weakens with the flattening ridge aloft Weds night into Thursday with another wave of low pressure heading east - this time tracking through the southern Great Lakes/Ohio Valley. The boundary to our south doesn't make much progress as the surface low is weak along with no significant llj to help push the front northward. PoPs however increase in the afternoon into nighttime with the approach of the surface low and associated moisture and lift. Best guess right now is that this system shifts through at some point Thursday night into Friday, but there's uncertainty with this timing. There's also the potential of yet another wave of pressure forming to our west and maintaining rain chances through all of Friday. NBM was used for temperatures through the long term. && .AVIATION /17Z SATURDAY THROUGH WEDNESDAY/... High pressure remains in place through tonight. VFR into early evening, then MVFR develops later this evening, with cigs lowering to IFR overnight. A shower possible starting late this afternoon, however rainfall doesn't become likely until Sunday afternoon. ESE-SE winds around 10kt through the TAF period. NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Timing of IFR onset may be forecast to be a couple of hours too soon, and even possible that cigs do not lower to IFR at all tonight. OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY... Sunday...MVFR/IFR. Showers likely mainly in the afternoon. SE winds G15-20kt. Monday...MVFR/IFR in the morning, then MVFR/VFR in the afternoon. Tuesday...VFR. Wednesday...MVFR or lower with a chance of showers. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Sub-SCA conditions can be expected through the weekend with high pressure along the New England coast maintaining an easterly or southeasterly flow across the waters and speeds generally at or under 10 kt. Winds and seas should then remain below SCA criteria through the middle of next week with a weak pressure gradient in place. && .HYDROLOGY... There are currently no hydrologic concerns through next week. && .TIDES/COASTAL FLOODING... Astronomical tides will increase with the approach of a new moon Tuesday night along with the threat of minor coastal flooding each night through this period and possibly including Wednesday night as well. A coastal flood statement has been issued for this evening's high tide cycle across Southern Fairfield County with benchmarks expected to be just reached in a few spots. Statements may be expanded to include Southern Westchester and Southern Nassau Counties for Sunday night. Advisories may eventually be needed for these zones and Southern Queens Monday night, and even more so for Tuesday night. Statements may be needed during this period for other parts along western LI Sound as well as lower NY Harbor. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ ####018004598#### FXUS63 KDTX 041702 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 102 PM EDT Sat May 4 2024 .KEY MESSAGES... - Morning fog and low clouds give way to a warm Saturday with highs in the low to mid 70s. - Scattered showers and possible non-severe thunderstorms this evening through Sunday morning. && .AVIATION... Moisture will increase from south to north again this afternoon and evening as mid level wave ejects into the general area in advance of approaching frontal system. Expect a trend from lower VFR back to MVFR with a few showers possible with this moisture especially into evening. IFR/lower MVFR stratus still looks likely overnight as the moist southerly flow persists before frontal passage early Sunday morning. While this front looks pretty dry, a few showers will be possible with its passage. Ceilings will slowly erode/lift within west to northwest flow in its wake on Sunday (especially by aft). For DTW/D21 Convection...Southeasterly winds today will drive weak instability across the airspace after 21Z. Isolated thunderstorms are possible within this environment. Forecast probabilities suggest a 20 percent chance across the southern portions of the airspace. DTW THRESHOLD PROBABILITIES... * Low for thunderstorms late this afternoon into tonight. * Moderate for ceilings aob 5000 feet this afternoon, high by the overnight period into Sunday morning. && .PREV DISCUSSION... Issued at 307 AM EDT Sat May 4 2024 DISCUSSION... Despite the showers and clouds yesterday, high temperatures were able to sneak into the lower 70s across most areas. Extremely dry airmass noted with the 00z APX raob, and some of the mid level dry air has/will make inroads into southeast Michigan. However, cool northeast flow off Lake Huron and lingering low level moisture looks sufficient to saturate the low levels, and deep enough moisture (5+ kft layer) to potentially trigger stray light rain showers, especially toward the southern Michigan border, as some of the deeper moisture over Ohio attempts to work back north late in the day, ahead of a weak cold front moving through from the western Great Lakes tonight. With surface capes under 1000 J/kg today and the mid level dry slot, do not see EQL levels getting high enough to generate thunderstorms during the daytime, but a slight chance of non-severe storms appears warranted this evening/tonight with the modest height falls and the slightly negative showalter values tracking through. Stability will be on the increase 15-17Z Sunday as the front clears the State. Despite a fair amount of clouds today and the early morning fog, will allow high temperatures to reach into the mid 70s across most locations, based on the forecasted 925 MB temps of 17 C. Westerly confluent upper level flow Sunday night preceding an upper level ridge axis arriving early next week, supporting dry weather on Monday and likely during the daylight hours of Tuesday before a warm front brings widespread showers and possible thunderstorms Tuesday evening/night. MARINE... An area of high pressure centered over the region this morning is resulting in a weak gradient with light winds and waves across the region. Elevated dew points within the stable environment have resulted in areas of dense fog across Lake Huron and a Dense Fog Advisory is in effect until noon today. The gradient increases this afternoon as the high departs east, with wind organizing out of the southeast late today into tonight. A stalled front lifts north as a warm front tonight as a weak low moves from the upper Mississippi Valley into the northern Great Lakes. The system then sends a cold front through early on Sunday with a chance of showers and thunderstorms. Wind shifts to northwesterly behind the front Sunday afternoon, peaking at around 15 to 20 knots. High pressure then builds in to bring quiet marine conditions for Monday and much of Tuesday. The next warm front moves into the area late on Tuesday with stronger easterly flow developing ahead of it. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ AVIATION.....DG DISCUSSION...SF MARINE.......TF You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit. ####018007412#### FXUS66 KLOX 041702 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 1002 AM PDT Sat May 4 2024 .SYNOPSIS...04/922 AM. A cold storm system will move over the region through Sunday bringing periods of light rain to the area this afternoon and evening. Temperatures will be much cooler than normal through Sunday and there will be gusty winds at times. Dry and warmer weather is expected next week. && .SHORT TERM (TDY-MON)...04/947 AM. ***UPDATE*** A weak but unusually cold storm system will move through California today into early Sunday. Really no changes in the timing and amounts from earlier predictions. Light rain has made it as far south as Monterey as of 9am and should be reaching the SLO County line by early afternoon. While northwest SLO County still stands to get around a quarter to half inch of rain with this system, due to the storm moving inland over northern California rain amounts drop off pretty fast to the south. The exception being southeastern LA County and the north facing mountain slopes where up to a third of an inch of rain is expected. In the downsloping area between southern Santa Barbara County and western LA County amounts drop off to a tenth of an inch or less. In most areas the duration of rain will be short, around 3-4 hours. ***From Previous Discussion*** Snowfall amounts will be light. While snow levels will lower down to 4000 to 4500 feet late tonight or early Sunday morning, most of the moisture will likely vacate the area by that time. At most, a dusting to an inch of snow are likely with local amounts up to two inches. Gusty winds will start to develop across the San Gabriel Mountains, and the Antelope Valley and the adjacent foothills this afternoon and this evening as the surface pattern tightens ahead of the cold front. A wind advisory remains in effect for this afternoon and tonight for these areas. After the front passes over the region, a tight surface pressure gradient will remain into Sunday and Sunday night. There is a good chance that the advisory for the San Gabriel Mountains, and the Antelope Valley and the adjacent foothills may need to be extended into Sunday and Sunday night. Wind advisories were added for the entire coastal areas and into the Santa Ynez Valley for gusty west winds on Sunday afternoon and evening, and for the Transverse Ranges and into southern Santa Barbara County for gusty northwest winds developing late tonight through early Monday morning. A cold air mass will spread into the area today and Sunday. There is a moderate chance that low maximum temperatures records could fall on Sunday out in the desert as the air mass will be cold for May, more inline with February or March. Temperatures in the 60s will be common across most areas the next several days, coldest on Sunday for areas south of Point Conception. .LONG TERM (TUE-FRI)...04/529 AM. The forecast ensemble members continue to suggest a warming and drying trend developing through Wednesday as high pressure aloft reestablishes over the eastern Pacific Ocean and a low pressure system dives through the Great Basin. There is a chance that a cool down could arrive for late week as onshore flow increases. EPS ensembles continues to keep cloud cover means free of the marine influence, but confidence remains moderate at best due to the time of the year. && .AVIATION...04/1701Z. At 1600Z at KLAX, the marine layer was 3800 feet deep. The top of the inversion was at 5600 feet with a temperature of 13 degrees Celsius. Overall, low to moderate confidence in 18Z TAF package. Combination of deep marine inversion with approaching weak system will bring clouds and visibilities ranging from IFR to MVFR through the period. Confidence in timing of flight category changes will be low through the period. Light showers will be possible across the area late this afternoon through tonight. KLAX...Moderate confidence in 18Z TAF. There is a 30% chance of MVFR CIGs 18Z-04Z. For tonight, high confidence in return of MVFR CIGs, but only moderate confidence in timing (could be +/- 3 hours of current 04Z forecast). High confidence in VFR conditions after 15Z. No significant easterly wind component is expected. KBUR...Moderate confidence in 18Z TAF. There is a 40% chance that VFR conditions will develop 18Z-03Z. For tonight, high confidence in return of MVFR CIGs, but only moderate confidence in timing (could be +/- 3 hours of current 03Z forecast). && .MARINE...04/710 AM. In the Outer Waters, winds and seas may drop below Small Craft Advisory (SCA) levels several hours late this morning/afternoon, but are expected to increase again late today. Widespread SCA level winds/seas are expected tonight thru Sunday afternoon, except will likely drop below SCA levels in the northern zone (PZZ670) late tonight. Winds will increase Sunday, with gales possible late Sunday into Sunday night in the southern two zones (PZZ673/676) and SCA conditions in the northern zone. SCA conditions are expected Monday thru Wednesday, with a 40% chance of gales Monday afternoon/eve. In the Inner Waters North of Point. Sal, SCA level winds/seas are likely in the afternoon/evening hours today thru Wednesday. There is a chance that seas will remain at or above SCA levels even when winds weaken, especially Sunday night/Monday night. In the Inner Waters south of Point Conception, SCA level W-NW winds are expected to spread from west to east across the waters this evening and early tonight, then continue thru Sunday afternoon. There is a 50% chance of gales Sunday afternoon into late Sunday night, especially in western portions. SCA level seas may persist into Monday. SCA winds are likely during the afternoon/evening hours Monday thru Wednesday in the Santa Barbara Channel, with a 30% chance of SCA conditions extending into the southern inner waters from Anacapa Island to Malibu. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory in effect from 10 AM to 9 PM PDT Sunday for zones 87-340-341-346>348-354-355-362-366. (See LAXNPWLOX). Wind Advisory in effect from 11 PM this evening to 3 AM PDT Monday for zones 349>353-376>378. (See LAXNPWLOX). Wind Advisory remains in effect until 5 AM PDT Sunday for zones 379>383. (See LAXNPWLOX). PZ...Small Craft Advisory in effect from 3 PM this afternoon to 3 AM PDT Sunday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 9 PM this evening to 3 PM PDT Sunday for zones 650-655. (See LAXMWWLOX). 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 Sunday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PDT Sunday for zones 673-676. (See LAXMWWLOX). && $$ PUBLIC...MW/Hall AVIATION...RAT MARINE...DB/RAT SYNOPSIS...MW weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox