####018008968#### FXUS62 KRAH 032359 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 800 PM EDT Fri May 3 2024 .SYNOPSIS... Sub-tropical high pressure will extend across the South Atlantic states today, while a backdoor cold front will move through eastern VA and northeastern NC. The front will settle southwestward and into north-central NC tonight, where it will stall through Saturday night, then weaken and move northward into VA on Sunday. && .NEAR TERM /THROUGH TONIGHT/... As of 355 PM Friday... Convection has indeed developed along the differential heating zone described below, while a few isolated cells have otherwise developed in areas of towering cumulus within a lee surface trough over the Piedmont (in and around the Triad and more recently over swrn Wake Co.). Some merging of outflows and additional, pulse/multi-cell development will remain possible with the upstream/differential heating-forced convection into the srn and wrn NC Piedmont through this evening. TCLT has measured 30-40 kt velocity from downdrafts with these cells around SVH and AKH in the past hour. Similarly strong gusts will be possible with these and other more-isolated ones over the Piedmont, where SPC Meso-Analysis data indicates 1000- 1200 J/kg of DCAPE has developed this afternoon. .PREV DISCUSSION... /ISSUED 1145 AM EDT Fri May 03 2024/ A mid/upr-level ridge centered near the srn Middle Atlantic coast will remain so through tonight, while a mid-level trough and embedded, weak MCVs now over the ern OH and TN Valleys will be directed around the ridge and into the cntl Appalachians. At the surface, a 1019-1020 mb sub-tropical high will remain situated off the coast of the Carolinas. Meanwhile, a backdoor cold front, now stretching from the mouth of the Chesapeake Bay nwwd to a 1014 mb frontal low over OH, will merge with a developing bay breeze and move swwd to the vicinity of the Roanoke River between 22Z-00Z. A separate, srn stream front extending from cntl TX enewd and across the lwr MS and TN Valleys, to a 1013 mb frontal low over Middle/wrn TN, then ewd across nrn GA and the Piedmont of the Carolinas, will move little through the period. With no airmass change from Thu and continued influence of ridging aloft, today will be persistently, unseasonably warm, with temperatures continuing at 10-15F above average - mid 80s to around 90. Showers and isolated storm will focus today along both fronts noted above, including into the NC nrn Coastal Plain and far ne Piedmont early this evening and also with diurnal heating along a differential heating zone evident in late morning visible satellite and surface observational data along the srn stream front from AGS to HKY. The latter activity, should it indeed develop, would then be steered in weak wswly steering flow and into the srn and wrn NC Piedmont late this afternoon-evening. Areas of persistence fog and low stratus will likely redevelop into the srn-cntl Coastal Plain and ern Sandhills tonight, while a separate area of post-frontal, very low stratus will develop behind the backdoor front across the ne Piedmont and nrn Coastal Plain. Temperatures tonight will remain unseasonably mild and mostly persistent in the upr 50s to mid 60s. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 230 PM Friday... Aloft, the sub-tropical ridge will stall along the eastern seaboard through Sat night. A southern stream disturbance will move into the Southeast US on Sat, then lift newd through the area as a sheared out northern stream s/w moves through the OH Valley/Great Lakes Sat night. The sub-tropical ridge will shift offshore and breakdown Sun/Sun night as the disturbances move through the mid-Atlantic and Northeast US. Another southern stream s/w will develop over the southern Plains on Sun, then move eastward into the lower/mid-MS Valley Sun night. At the surface, as high pressure sits over the New England coast, the backdoor cold front is expected to stall over nrn/nern NC through Sat and into Sat night then lift northward late Sat night/Sun. The high should move eastward over the Atlantic as a low moves through the Great Lakes and into the Northeast Sun/Sun night. Precipitation/Convection: Still fairly high confidence/chances for showers and possible storms Sat and Sun. Best threat for storms will be across the Piedmont, mainly along and south of the surface boundary, where surface-based CAPE will be maximized. Bulk shear still appears weak, and PWATs are expected to range from 1.4 to 1.8 inches. Do not expect the entire day to be a wash-out by any means, and Sat could start dry for most, but there will be a chance for showers across all of central NC, with greatest coverage from Sat eve through Sun aft. Highest chances NW, lowest SE. Given the high PWATs and scattered, somewhat disorganized mode of convection, isolated locations could receive locally heavy rainfall, with any potential for minor flooding issues largely limited to urban areas. Temperatures: A bit tricky on Sat, as there is some bust potential north of the front. Widespread overcast skies should somewhat limit heating as well. For now expect highs to range from the mid 70s along the NC/VA border to mid 80s SE. Sat night temps should be continued mild, mainly in the low to mid 60s. On Sun, with the retreat of the front northward, areas across the north may be a few degrees higher than Sat, but given the expected showers/storms through the day, temps may otherwise be limited. Highs in the upper 70s north to low 80s south. && .LONG TERM /MONDAY THROUGH THURSDAY... As of 329 PM Friday... The extended forecast upper pattern will largely include mid-level ridging over the eastern US. A stronger short-wave will move over the area Monday into Tuesday increasing rain chances. After relatively zonal flow Tuesday, mid-level ridging will then re- amplify over central NC through the end of the extended. Another potentially stronger trough may approach late in the period. Monday/Tuesday: A potent mid-level short-wave and associated vorticity max is forecast to move across the southern Appalachians Monday afternoon. Mid-level height falls will maximize over us later Monday afternoon/early evening coinciding with peak heating/instability. At the sfc, a piedmont trough will develop Monday afternoon which, in combination with forcing aloft, should help to focus showers and storms across our area. Bulk layer shear will be much too weak to support severe storms, but given the presence of anomalous PWAT (150 to 200 % of normal) any storm that develops could produce brief heavy downpours and gusty winds. POPs should decrease late Monday night/early Tuesday morning as flow aloft turns a bit more nwly and the atmosphere stabilizes. In absence of upper forcing aloft, rain chances Tuesday afternoon will largely rely on diurnal shower/storm development which should remain mostly scattered. Temperatures Monday will peak in the mid to upper 80s, increasing into the upper 80s by Tuesday afternoon. Wednesday/Thursday: The mid-level ridge will re-establish itself Wednesday and Thursday as temperatures soar into the lower to mid 90s. The NBM is particularly stoked about 90 temps for highs these days with >80% of it's members reaching this threshold for much of this area. The LREF (GEFS, GEPS, EPS) is a little less enthused on Wednesday, but does suggest decently high probabilities on Thursday (generally 40 to 60 % across the area). Otherwise, anomalous moisture will remain in place Wednesday/Thursday which should promote a continuation of low-chance POPs each afternoon. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 800 PM Friday... Generally VFR conditions will continue through 06z tonight. IFR to LIFR CIGS and MVFR vsbys are expected to develop over a swath of central NC later tonight 08z-09z and linger into Saturday 15z-16z. In addition scattered showers will become more numerous Saturday, with isolated thunderstorms. The showers will linger into Saturday night with lingering IFR to LIFR conditions. Outlook: IFR-MVFR ceilings are likely to redevelop each night- morning through Monday, as are scattered to locally numerous showers/storms each afternoon-evening. && .CLIMATE... Record High Minimum Temperatures: May 4: KGSO: 65/2022 KRDU: 68/1938 KFAY: 68/1942 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...KC LONG TERM...Luchetti AVIATION...pwb/MWS ####018006186#### FXUS62 KFFC 040000 AAA AFDFFC Area Forecast Discussion...UPDATED National Weather Service Peachtree City GA 800 PM EDT Fri May 3 2024 ...New 00Z Aviation Discussion... .SHORT TERM... (This evening through Saturday) Issued at 306 PM EDT Fri May 3 2024 At a glance: - Multiple waves of precipitation through the weekend - Brief reprieve from unseasonably warm temperatures Saturday north of I-20 At the surface, conditions are relatively benign, with the western fringes of surface high pressure still in place across the Southeast. The primary catalyst for our rather dreary weekend ahead will be a series of shortwaves traversing mid-level flow aloft, the strongest of which looks to move through Saturday afternoon. Development through this afternoon is likely to be patchy and summer-like, with slight chance to low-end chances (20-40%) for showers and thunderstorms. Saturday, with the arrival of better (but meager) forcing and a slug of mid-level moisture, rain chances are likely to be more widespread and weakly organized, with fewer breaks in between individual waves. For both days, MUCAPE looks to reach into the 1000-1500 J/kg range, but unimpressive shear (<20kt bulk) will preclude meaningful chances for severe weather. That said, PWATs creeping north of 1.5" areawide puts us at approximately the 90th percentile for early May per the SPC's sounding climatology. Any storms that form are likely to be slow-moving to stationary, and will be capable of producing locally heavy rainfall, ponding on roads, and perhaps nuisance flooding. Highs today will continue the trend of being several degrees above average, in the upper 70s to 80s, with 90 in reach across south central Georgia. Tomorrow will be cooler north of I-20 -- highs in the 60s are not out of the question for portions of north Georgia, though generally in the 70s to near 80 -- thanks to greater coverage of clouds and thunderstorms. South of I-20, expect another day with temperatures reaching into the low-to-mid 80s. 96 && .LONG TERM... (Sunday morning through next Thursday) Issued at 306 PM EDT Fri May 3 2024 As the extended period picks up on Sunday morning, a shortwave disturbance will be positioned over the ArkLaTex. This disturbance will move northeastward over the course of the day on Sunday and into Monday, which will force continued scattered to numerous showers and thunderstorms across the forecast area. The coverage of thunderstorms will moreover be diurnally enhanced in the afternoon hours each day. The combination of forcing ahead of the shortwave, diurnal instability, and precipitable water values ranging from 1.4 to 1.7 inches will be sufficient for likely PoPs across the majority of north and central Georgia each afternoon, with some activity lingering into the evening each day. Low-level wind shear and dynamic support appears that it will be located nearest to the axis of the shortwave, which will pass north of the forecast area. As such, a widespread severe weather threat is not anticipated, but a few storms each day could become strong and capable of producing locally heavy rain, gusty winds, and frequent lightning. A relatively drier period is expected on Tuesday into Wednesday with a mid-level ridge building over the Southeast. Temperatures will gradually warm under the ridge, with highs climbing a couple of degrees each day and reaching into the upper 80s in north Georgia and low 90s in central Georgia on Wednesday. These temperatures will be between 8-12 degrees above climatological normals. Widely scattered showers and isolated thunderstorms are forecast to be confined to the far northern tier each afternoon on Tuesday and Wednesday. By Thursday, an upper level trough will extend from the High Plains to the Four Corners region while subtropical ridging strengthens over the Gulf of Mexico. With a tightening pressure gradient between these features, much of the Southeast will be under strengthening southwesterly flow aloft. Meanwhile, a frontal boundary will advance slowly southward from the lower Midwest into the Tennessee River Valley. A series of disturbances traversing the upper level flow is anticipated to overrun the front, which will help organize thunderstorms across northern portions of Georgia. With a warm and unstable airmass across much of the Southeast and increased deep- layer bulk shear ahead of the advancing front, the potential for severe weather on Thursday will need to be monitored as the forecast evolves. King && .AVIATION... (00Z TAFS) Issued at 738 PM EDT Fri May 3 2024 Isolated SH and TS are underway across north and central GA. Have a TEMPO for MCN for TS given colliding outflow boundaries nearby. Will need to watch the SH west of ATL for lightning. CIGs will lower to MVFR/IFR and VIS to MVFR after ~09z through late tomorrow (Saturday) morning, during which time scattered SH are expected. MVFR/low-VFR conditions are expected tomorrow afternoon and early evening with scattered TS. Winds will be SE to SW at 3-8 kts. //ATL Confidence...00Z Update... Medium confidence on CIG/VIS evolution and SH/TS timing. High confidence on all other elements. Martin && .PRELIMINARY POINT TEMPS/POPS... Athens 64 79 62 83 / 40 70 50 60 Atlanta 65 81 64 83 / 50 70 40 60 Blairsville 60 74 59 78 / 70 80 50 80 Cartersville 63 81 62 83 / 50 60 40 60 Columbus 66 87 65 88 / 40 40 30 50 Gainesville 64 78 64 81 / 40 70 50 70 Macon 66 83 64 85 / 30 60 40 60 Rome 64 82 62 85 / 60 60 40 70 Peachtree City 64 83 62 84 / 50 60 30 60 Vidalia 68 83 66 87 / 40 50 30 60 && .FFC WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...96 LONG TERM....King AVIATION...Martin ####018004372#### FXUS62 KCAE 040001 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 801 PM EDT Fri May 3 2024 .SYNOPSIS... Increasing moisture and shortwave energy will lead to active weather for the weekend through early next week with showers and thunderstorms likely. For the remainder of next week, expect well above normal temperatures and at least a slight chance of showers and thunderstorms each day. && .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... Isolated showers in progress. Latest guidance indicates additional convective development late tonight, mainly western half of the forecast area, ahead of a slow moving upper short wave approaching from the west. Lows in the low to mid 60s. && .SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... The axis of an upper trough is expected to continue sliding eastward, putting us in a southwest flow aloft regime for the next couple of days. A series of embedded shortwaves are forecast to move over the region. At the surface, high pressure off the coast remains generally in place, allowing for southeast surface winds across the forecast area. As a result of this combination, PWATs are expected to increase to 1.6-1.7 inches, which is near the climatological top of moisture for this time of year. With this amount of moisture available, expect scattered showers and thunderstorms to spread across the area Saturday and Sunday, with peak coverage in the afternoons. With a lack of low level forcing mechanism, most of the activity is likely to be driven by the passing shortwaves. With the ridging aloft, instability and shear are limited, especially shear. Therefore, severe thunderstorms are not really expected. With the widespread cloud cover and scattered shower and thunderstorm activity, daytime temperatures are forecast to be closer to average for this time of year compared to the past couple of days. The increased moisture is expected to keep temperatures several degrees above average each night. && .LONG TERM /MONDAY THROUGH FRIDAY/... A persistent pattern of broad ridging, with passing shortwaves over the Southeast is expected to bring a continued summer-like pattern to the region. This should lead to nearly daily shower and thunderstorm chances through midweek, but coverage is anticipated to steadily decline after Monday. Temperatures are also expected to gradually increase due to the stagnant pattern aloft, with highs mid to late week in the lower to mid 90s. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... VFR conditions expected early in the forecast then increasing confidence in restrictions on Saturday. Some weakening showers along an outflow boundary should have little impact on terminals this evening and remainder of convection should remain to the west. Widespread clouds are expected over the region overnight with abundant moisture over the region and continued moisture advection. Shortwave energy moving northeastward from the central Gulf Coast states should bring an increase in showers to the CSRA around or shortly after sunrise Saturday and these showers are expected to continue to move into the Midlands through the day with increasing shower coverage impacting many of the terminals. Thunderstorms will be possible but low confidence in whether they will directly impact terminals at the back end of forecast. Many guidance sources are indicating lower restrictions in stratus during the predawn hours and continuing through the day Saturday, with highest confidence at AGS/DNL coinciding with the expected rain moving in and lower confidence at OGB. Including some tempo MVFR cig restrictions during the predawn hours at AGS/DNL and arriving slightly later at CAE/CUB, then carry prevailing restrictions into the early afternoon hours, all but OGB which should lose the lower cigs earlier. Cannot rule out some MVFR fog at AGS/DNL as well. EXTENDED AVIATION OUTLOOK... Late night/early morning fog/stratus possible through the period. Scattered to numerous showers and thunderstorms expected Sunday and Monday with decreasing chances Tuesday onward. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$ ####018008377#### FXUS61 KPBZ 040002 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 802 PM EDT Fri May 3 2024 .SYNOPSIS... Precipitation chances increase this afternoon and evening and continue through the weekend. Cooler, but still above average, temperatures prevail Saturday and Sunday with warm and unsettled weather continuing into next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... KEY MESSAGES: - Showers and thunderstorms expected this evening, with decreasing coverage overnight. - Temperatures well above average tonight, with record warm minimum standards being approached. ------------------------------------------------------------------- Weak but noted 700mb shortwave movement amid a warm, moist environment with limited elevated instability will continue to push a wave of showers with embedded lightning through the Upper Ohio River Valley this evening. Precipitation chances are likely to dwindle beyond midnight as the shortwave wave exits, surface lift/heating is nonexistent, and elevated instability wanes. The higher terrain of WV and the Laurel Highlands figure to have the highest chances for residual showers through 6am Saturday given weak surface convergence between NW flow to the west and SE to the east. Limited air mass change at the surface combined with excessive cloud cover will buoy overnight temperature, putting a few record high minimum temperature at area climate sites at risk (see more details below). The likely limiting factor will be the effects of precipitation cooling that will bring area temperature closer to current upper 50s to lower 60s regional dew point values. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... KEY MESSAGES: - Unsettled pattern remains with rain chances continuing through Sunday. Thunder possible on Sunday. - Temperatures drop, but still remain above normal. ------------------------------------------------------------------- Eastward progression of the 500mb ridge axis slows considerably over the northeast CONUS on Saturday, with the quasi-stationary surface boundary lingering near the PA/OH border. Shortwave energy riding up the Ohio River will spread rain over the entire forecast area during the day. Areas near and to the west of the stalled boundary will have the bulk of the modest instability during the afternoon, leading to better chances of thunderstorms and notable rainfall. NBM probabilities of greater than 0.25" of rain are highest in far western PA and eastern Ohio, as expected given the above. The clouds and rain will keep temperatures suppressed as compared to recent days. In fact, easterly flow into the ridges may keep daytime highs some 15-20 degrees cooler in that region as compared to today. The upper pattern shows better movement on Sunday, as increased troughing over the northern Great Lakes shunts the larger trough axis eastward, with the northeast CONUS ridge crossing into the Atlantic. Shower coverage should be reinforced by the approaching trough and a secondary frontal boundary. Instability of greater than 500 J/kg has 50% or greater probability across most of the forecast area according to the NBM, thus thunderstorms are a higher probability. Severe chances remain quite low as overall instability remains marginal and flow is relatively weak in the lower and mid levels. Temperatures will recover a bit in south/southwest flow, with most non-ridge areas reaching the 70s once again. Most-likely rainfall totals across the region roughly in the 1.0 to 1.25 inch range through Sunday, with isolated higher totals likely. Large-scale flooding concerns remain small given the relatively dry antecedent conditions, but slow storm motions could lead to isolated issues if any one location gets hit multiple times with thunderstorms. && .LONG TERM /MONDAY THROUGH FRIDAY/... KEY MESSAGES: - Rain chances continue into early next week but more uncertainty lends lower confidence. - Temperatures favored to remain above normal. ------------------------------------------------------------------- Ensembles have been consistent in showing a shortwave trough over the Middle Ohio Valley approaching, but weakening, on Monday as it interacts with flat ridging over our region. A south-to-north gradient in PoP values still seems appropriate for the Monday/Monday night period. Uncertainty still reigns after Monday. Most guidance depicts a ridge centered over the Great Lakes at 12Z Tuesday, along with a deep closed upper low in or near the Dakotas. The upper low appears likely to fill during the midweek period, and as it does so, shortwaves rotating around it appear to flatten out the ridge as it moves across the Upper Ohio Valley, finally eroding it almost completely in the northeast CONUS. Some strength and timing issues remain with the details of this process, which in turn could impact precipitation amounts and timing. Nevertheless, a warm front is likely to cross on Tuesday as the ridge progresses eastward. This will lead to the persistence of a warm and moist airmass, with precipitable water values at or above the 90th percentile in the climatology. Along with the previously mentioned shortwave activity, this will keep an active weather pattern in place for our region, with decent daily precipitation chances through Friday. Deep-layer shear will increase as well behind the departing ridge, so severe weather chances will need to be monitored as well. According to CSU machine-learning guidance and NBM CWASP probabilities, Wednesday and Thursday may be the days to watch. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... VFR ceilings and scattered light showers are ongoing across the area this evening. Removed the mention of thunder from 00Z TAFs as instability is waning and any lingering occurrences of lightning would be brief and isolated, with little impact to area terminals. Into tonight, convection is expected to subside in coverage, with only some light lingering showers possible primarily southeast of a ZZV-PIT-DUJ line. Meanwhile, saturation from the rain and cooling temperatures may allow an MVFR cloud deck to settle in by daybreak as winds shift to southeasterly. The highest probabilities for ceiling restrictions, per the latest hi-res ensemble guidance, exist north and west of Pittsburgh, across portions of eastern Ohio and northwestern PA. East of PIT, it appears downsloping southeasterly winds may help keep low-level moisture profiles slightly less saturated and thus, mitigate the formation of widespread MVFR/IFR ceilings. Widespread rain chances increase again after 18Z Saturday. Locally lower ceilings and visibilities can be expected in the heavier showers. Continued to leave thunder out of the TAFs during that period given uncertainty surrounding how much instability will develop. If lightning does occur, the best chances according to hi-res ensembles would be southwest of PIT, so a mention of thunder at ZZV and HLG may be needed in future updates. .Outlook... Restriction potential continues through Sunday morning, with additional storm chances Sunday afternoon. Periodic restrictions may continue through early next week as multiple disturbances pass through the region. && .CLIMATE... Some record warm minimum temperatures may be approached on Saturday. Below is a table showing the latest forecasted low temperature for each climate site, their respective record value, and the year it was set. Forecast Record Year Pittsburgh 60 65 1938 Wheeling 62 63 1931, 1939, 1941 Morgantown 61 63 2021 New Philadelphia 60 60 2012 Zanesville 63 65 1902 && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...CL NEAR TERM...Frazier SHORT TERM...CL LONG TERM...CL AVIATION...Cermak/Milcarek CLIMATE...Frazier ####018006813#### FXUS63 KABR 040002 AAA AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 702 PM CDT Fri May 3 2024 .KEY MESSAGES... - Scattered rain showers late this afternoon will become more widespread over the eastern part of the region tonight. Rainfall amounts of one quarter to in excess of one half inch are expected along and east of a line from Wheaton, MN to Murdo. - High pressure will bring dry and warmer conditions this weekend. - A much larger system looks to affect the region on Monday, with widespread moderate rainfall. The threat for severe weather still appears low at this time (higher across NE/KS/OK), but we will continue to monitor trends. && .UPDATE... Issued at 647 PM CDT Fri May 3 2024 See below for an aviation forecast discussion for the 00Z TAFs. && .SHORT TERM /THIS EVENING THROUGH SATURDAY NIGHT/... Issued at 315 PM CDT Fri May 3 2024 An upper level trough currently west of the region will track across the Dakotas tonight, with a fairly potent shortwave affecting mainly the eastern part of the CWA. The trough weakens as it exits the area on Saturday, with ridging then building in Saturday night. At the surface, the region is currently situated between a low pressure system over southern Ontario and a low over Colorado. The boundary between these two systems will be the focus for rain late this afternoon and tonight as the aforementioned shortwave moves over the area. Currently seeing some scattered shower activity over mainly the western half of the CWA, but expect this area of rain to become more of a line from southwest to northeast by this evening, generally extending along and east of a line from west central Minnesota to Murdo. The area of rain will then spread eastward tonight. Right now, thunderstorm potential looks to stay south of the CWA, but cannot rule out a stray thunderstorm maybe affecting the southeastern CWA this evening. The highest rainfall amounts are expected along and east of a line from Wheaton, MN to Murdo, where one quarter to one half inch looks to occur. Should a thunderstorm develop, there could be some locally higher amounts. High pressure will settle over the region Saturday and Saturday night, bringing a return to dry conditions. Low temperatures tonight will range from the lower 30s along and west of the Missouri River, to the lower 40s across west central Minnesota. High temperatures on Saturday will be in the upper 50s to mid 60s. Lows Saturday night will be in the mid to upper 30s. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 315 PM CDT Fri May 3 2024 This forecast period begins Sunday morning on a relatively quiet note compared what were anticipating to be another round of active and wet weather through the majority of next week. Upper level ridging will build overhead on Sunday in response to an upper level trough/low moving through the Great Basin and adjacent regions of the western CONUS. Sfc high pressure will be positioned off to our east while low pressure will be situated across the lee of the Rockies and Northern High Plains on Sunday. Southerly low level flow will intensify through the daytime as the pressure gradient tightens. Increasing southerly winds through the day will potentially reach advisory criteria, especially across our western zones. NBM probabilities of seeing max wind gusts greater than or equal to 34kts(40mph) is high(70-100%) along and west of the Missouri Valley. At this point in time, the thinking is that this is a bit on the high category or extreme, so will continue to take a more conservative approach and keep an eye on trends with incoming future guidance data. With a decent amount of sunshine to round out the weekend and dry conditions expected, we should see a nice warm up. 950mb temps are expected to reach about +13C to +19C which translate to highs in the 60s to low 70s across the forecast area. Unfortunately, all good things have to end sometime and we'll see the pattern shift quickly by Monday into a more active and wet one. The aforementioned upper low is progged by both deterministic and ensemble guidance to track northeastward out of the Rockies into portions of the Northern High Plains and Northern Plains early next week. This system looks to be rather vigorous on Monday as sfc low will track into the Central Plains and shift northward into our region. Severe weather parameters looks best across the Central Plains and south of our region by Monday afternoon and evening, however we can't totally rule out some stronger activity in parts of our area. As of right now, our forecast area is just outside of the northern fringe of the better instability. MUCAPE values on the order of about 300-500 j/kg is possible, especially across our southern zones with far more higher values to the south in parts of NE and KS. We'll just have to keep track of the trends over the next couple days to see if there's any movement farther north with these better ingredients. The upper flow pattern remains unsettled at least through the middle of next week and perhaps even through the end of this period. Guidance progs a stagnant pattern locally with the upper low or trough meandering and spinning just off to our northwest. Multiple s/w's in southwest flow aloft over our region will likely keep on and off shower chances persisting through the week. Underneath the more extensive cloud cover that anticipated, temperatures will be held in check close to normal but probably falling short of average for this time of year. Daytime values in the 50s and 60s can be expected with overnight temperatures in the 40s. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 647 PM CDT Fri May 3 2024 Terminals KABR,KATY,KPIR,KMBG Periods of MVFR cigs and MVFR/IFR vsbys will be possible under the banded rain shield that extends from south central South Dakota (KPIR) up through west central Minnesota (KATY). The whole band of rain is translating east-northeast, and is forecast to be clear of both KPIR and KATY by 06Z tonight. VFR conditions already ongoing at KMBG and KABR are forecast to persist through the TAF valid period. VFR conditions are forecast to establish at KPIR and KATY overnight and then prevail at those two locations through the rest of the TAF valid period. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Dorn SHORT TERM...Parkin LONG TERM...Vipond AVIATION...Dorn ####018007696#### FXUS61 KBUF 040004 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 804 PM EDT Fri May 3 2024 .SYNOPSIS... A weakening cold front will bring some showers to parts of the region this evening into tonight. Shower chances steadily decrease later tonight into Saturday with just scattered showers remaining, and some dry time built in. Another slow moving cold front will pass across the area Saturday night through Sunday bringing the next round of more widespread showers and possibly a few rumbles of thunder. High pressure then returns Monday, allowing for a dry start to the new work week. && .NEAR TERM /THROUGH TODAY/... A weakening occluded front will slowly work across far western New York this evening into tonight. This boundary will bring some light rain showers to the area, with no more than a few hundredths at best over any given location. As this front progresses east it will begin to fall apart, but there will still be some showers possible for some locales (east of Lake Ontario) overnight. Otherwise...it will be mild with lows mainly in the 50s. With very little forcing in place for Saturday, expecting just scattered showers, especially during the morning hours with a good deal of dry time built in through the day. Next stronger cold front will approach from the west late Saturday, while next wave moves north from the Ohio Valley. This will help to displace the upper level ridge east over New England, thus opening the door for the next surge of moisture and lift to move over the area with chances for showers increasing from south to north late in the day into the evening. Highs will be mainly in the 60s. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... The mid-level ridge axis over the forecast area through Saturday afternoon will push east toward New England Saturday night. In its wake, a shortwave trough will track northeast out of the OH/TN Valleys toward WNY. As the trough approaches, shower coverage will increase significantly from south to north through the later portion of Saturday evening and overnight. An influx of moisture with the trough will also help showers expand over the region. There still remains some uncertainty with track of shortwave trough and moisture over the forecast area with some models placing the higher rainfall amounts over WNY and other guidance more to the east toward CNY. An incoming cold front on Sunday morning will increase forcing over the area, prolonging and expanding the potential for showers through at least the afternoon hours. Still uncertainty with how quickly the cold front tracks through the region among guidance as well with some guidance prolonging the showers through most of the day and into the evening on Sunday. Overall though the later portion of Saturday evening through at least the early afternoon on Sunday looks to be soggy for most of the forecast area. The more organized showers on Sunday should be mainly across the eastern third of the area by the late afternoon, with some lingering/scattered showers across the rest of the area. With the large scale trough just north of the region still, along with lingering synoptic moisture, scattered showers will linger through most of Sunday night. Drier air moving into the area along a zonal flow will start to scatter out any remaining showers from west to east through the late night. Rainfall amounts of a quarter of an inch to half an inch is expected, with some higher amounts possible as well. Current thinking is the higher qpf amounts will be along the south shore of Lake Ontario east to the north country. Still plenty of uncertainty with higher qpf placement among guidance still. A ridge building into the region will result in drier weather for Monday through Monday night across the entire area. Clearing skies on Monday will result in increasing sunshine from northwest to southeast through the day. Clouds will linger the longest near the NY/PA line as a disturbance tracks south of the area. Temperatures on Sunday will be in the low 50s for the higher terrain east of Lake Ontario to the mid and upper 60s for the lower elevations south of Lake Ontario. For Monday, temperatures warm to the mid 60s to mid 70s from the higher terrain to lower elevations respectively. && .LONG TERM /TUESDAY THROUGH THURSDAY/... A sprawling mid and upper level low will start out this period over the northern Rockies and Upper Plains states on Tuesday...then will slowly drift eastward across the northern half of the CONUS through the remainder of the work week. This being said...the medium range guidance continues to exhibit considerable differences in the strength and rate of eastward progression of this low...and consequently also in the strength/timing of a number of shortwave impulses ejecting eastward from this system and across our region. With the above in mind...forecast confidence in associated precipitation potential/timing remains fairly low particularly from about Wednesday onward...and as such have undercut blended guidance a bit in an attempt to better reflect this uncertainty. In general this system should bring more unsettled weather with frequent opportunities for showers and perhaps a few thunderstorms during the middle and latter portions of next week...though likely also with some drier periods interspersed. As for temperatures...these will continue to average some 5-10 degrees above normal through this period. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... A weak occluded front will work across the region this evening bringing lowering VFR Cigs and showers across far western terminals. Tonight...flight conditions will slowly deteriorate with MVFR CIGS developing across the Southern Tier (KJHW), then advancing northward across the Niagara Frontier (KBUF/KIAG). Mainly VFR conditions expected to continue from the Genesee Valley eastward to include KROC and KART. Saturday...some scattered light showers expected with MVFR CIGS continuing across the Southern Tier (KJHW). KBUF/KIAG should improve to VFR by late morning/midday, with VFR flight conditions expected to continue from KROC east. Outlook... Saturday night and Sunday...VFR/MVFR with showers likely and possible thunderstorms. Monday...VFR. Tuesday and Wednesday...VFR/MVFR. Chance of showers with a slight chance of thunderstorms. && .MARINE... Mainly weak pressure gradients are expected to persist into this weekend across the lower Great Lakes supporting winds to generally remain below 15 knots. Expect this to bring some choppy waters at times, however conditions will remain below headline criteria, especially with an offshore flow developing tonight then persisting through the weekend, keeping the highest waves over Canadian waters for Saturday and Sunday. While quiet weather continues for the end of the work week, a few showers and thunderstorms will be possible tonight through Sunday. High pressure will build across the area for the start of the new work week providing mainly gentle breezes with no more than some light chop expected through Tuesday. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...AR/JM NEAR TERM...AR/JM SHORT TERM...SW LONG TERM...JJR AVIATION...AR/JM MARINE...AR/JM ####018004468#### FXUS62 KCAE 040004 CCA AFDCAE Area Forecast Discussion...CORRECTED National Weather Service Columbia SC 804 PM EDT Fri May 3 2024 .SYNOPSIS... Increasing moisture and shortwave energy will lead to active weather for the weekend through early next week with showers and thunderstorms likely. For the remainder of next week, expect well above normal temperatures and at least a slight chance of showers and thunderstorms each day. && .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... Isolated showers in progress. Latest guidance indicates additional convective development late tonight, mainly western half of the forecast area, ahead of a slow moving upper short wave approaching from the west. Some fog/stratus possible late tonight, mainly southern and eastern areas. Lows in the low to mid 60s. && .SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... The axis of an upper trough is expected to continue sliding eastward, putting us in a southwest flow aloft regime for the next couple of days. A series of embedded shortwaves are forecast to move over the region. At the surface, high pressure off the coast remains generally in place, allowing for southeast surface winds across the forecast area. As a result of this combination, PWATs are expected to increase to 1.6-1.7 inches, which is near the climatological top of moisture for this time of year. With this amount of moisture available, expect scattered showers and thunderstorms to spread across the area Saturday and Sunday, with peak coverage in the afternoons. With a lack of low level forcing mechanism, most of the activity is likely to be driven by the passing shortwaves. With the ridging aloft, instability and shear are limited, especially shear. Therefore, severe thunderstorms are not really expected. With the widespread cloud cover and scattered shower and thunderstorm activity, daytime temperatures are forecast to be closer to average for this time of year compared to the past couple of days. The increased moisture is expected to keep temperatures several degrees above average each night. && .LONG TERM /MONDAY THROUGH FRIDAY/... A persistent pattern of broad ridging, with passing shortwaves over the Southeast is expected to bring a continued summer-like pattern to the region. This should lead to nearly daily shower and thunderstorm chances through midweek, but coverage is anticipated to steadily decline after Monday. Temperatures are also expected to gradually increase due to the stagnant pattern aloft, with highs mid to late week in the lower to mid 90s. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... VFR conditions expected early in the forecast then increasing confidence in restrictions on Saturday. Some weakening showers along an outflow boundary should have little impact on terminals this evening and remainder of convection should remain to the west. Widespread clouds are expected over the region overnight with abundant moisture over the region and continued moisture advection. Shortwave energy moving northeastward from the central Gulf Coast states should bring an increase in showers to the CSRA around or shortly after sunrise Saturday and these showers are expected to continue to move into the Midlands through the day with increasing shower coverage impacting many of the terminals. Thunderstorms will be possible but low confidence in whether they will directly impact terminals at the back end of forecast. Many guidance sources are indicating lower restrictions in stratus during the predawn hours and continuing through the day Saturday, with highest confidence at AGS/DNL coinciding with the expected rain moving in and lower confidence at OGB. Including some tempo MVFR cig restrictions during the predawn hours at AGS/DNL and arriving slightly later at CAE/CUB, then carry prevailing restrictions into the early afternoon hours, all but OGB which should lose the lower cigs earlier. Cannot rule out some MVFR fog at AGS/DNL as well. EXTENDED AVIATION OUTLOOK... Late night/early morning fog/stratus possible through the period. Scattered to numerous showers and thunderstorms expected Sunday and Monday with decreasing chances Tuesday onward. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$ ####018006925#### FXUS62 KGSP 040005 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 805 PM EDT Fri May 3 2024 .SYNOPSIS... Dry and warm high pressure moves off the Carolina coast as a front approaches from the west then stalls over our region for the weekend. This front will result in periodic thunderstorms and showers starting today and lingering through the weekend. A general summertime pattern sets up early next week, which will likely support scattered thunderstorm development each afternoon. && .NEAR TERM /THROUGH SATURDAY/... As of 745 PM EDT: Still expect most of the area will be free of measurable precipitation for most of the night. Ridge axis still present over the SE Coast. Some disorganized bands of convection continue west of the Appalachians in the more unstable area upstream of the ridge, generally ahead of approaching shortwave. Little change in the pattern or vertical profiles tonight, such that scattered showers and perhaps a few t-storms are expected to continue in the Smokies and Balsams, south to the Savannah Valley. The current activity may wane diurnally before new development occurs overnight. At this point, main impacts from any storms are expected to be locally heavy rainfall. Outflow from earlier storms left behind a nearly saturated PBL in some spots, and some locally dense fog can't be ruled out in such areas overnight. However, cloud cover and dry profiles above the PBL suggest this is a low confidence forecast and perhaps localized issue. Will monitor temp trends thru the evening for possible revision to patchy fog wording now included in the fcst. Southerly flow is weak but should promote moisture advection into the lower Piedmont, possibly bringing fog and low stratus to those areas around dawn, but the higher cloud decks may keep that in check. Possibly more notably, the weak moisture advection may promote rapid development of convection around or after daybreak Saturday. Coverage should then increase for that reason and as forcing from the shortwave increases as the day continues. Instability and shear will remain on the weak side, while forecast profiles show an even more saturated atmosphere. This suggests and even less chance of strong to severe storms, with a slight uptick in heavy rain potential. That said, the overall flood risk remains low given the relatively dry antecedent conditions. Highs will be near normal due to clouds and precipitation. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 240 PM EDT Friday: The rest of the weekend looks active right into the first part of next week. A baggy upper trof overhead on Saturday night slowly lifts northeast with a short wave passage, and this bit of lingering forcing will be able to keep shower/thunderstorm activity on a slow wane into the early morning hours. Guidance suggests that it will never die off entirely, so the fcst retains some fairly high precip probs. That sets the stage for Sunday. Models show less forcing, but an uptick in the available buoyancy in the afternoon. That should make for a more thermodynamically-driven day, with better than climo coverage of showers and storms. Forecast soundings off the NAM show some pulse-severe wind damage potential with mid-level dry air and a shallow inverted-V, so it would not come as a surprise if it was a busier day than Saturday. A stronger short wave lifting northeast over the TN/OH Valley regions on Monday will continue to support diurnally-enhanced convection, so we continue with above climo precip probs. Temps look to be on the order of five degrees above normal. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 143 PM EDT Friday: The bulk of the medium range looks like a summer preview. After a baggy upper trof moves past Monday night, we should spend the remaining week underneath a low amplitude, relatively fast, WSW flow aloft. Within this flow, the model guidance shows a steady train of short waves moving through, mostly around peak heating each day, that will enhance our convective coverage each afternoon/evening. Overall, the air mass shows little change from one day to the next, as a wavy surface front will be strung out to our north in the WSW flow. Buoyancy will be modest and shear will be light, which suggests that chances for severe storms will be relatively low, but in such a pattern we eventually seem to manage to crank out a few pulse severe storms each day. Precip will be spotty and showery, which keeps the heavy rain threat at bay, but eventually there could be a few spots that start to see an increased risk of flash flooding, especially if a more coherent, stronger short wave comes along, such as what the GFS shows next Friday. Lots of uncertainty, though. Temps will remain in that 5-10 degree above normal range for most days, perhaps on the high side of that either Wednesday or Thursday, which one of those days might get a break in the wave train and thus reduced shower coverage and higher temps. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: -SHRA will approach KAVL and KAND this evening but chance of impacts small enough no mention is made in their TAFs. Multiple cloud decks above 070 will be seen tonight largely as a result of either convective debris or clouds forced by upstream shortwave. Sfc conditions will be moist tonight where precip outflow occurred Fri aftn, but otherwise low levels remain rather dry and extent of fog will be limited overnight especially given cloud cover. Some instability will persist overnight and new SHRA or even TSRA can't be ruled out after midnight near KAVL and the SC sites; S to SE PBL flow will serve as weak forcing. Restrictions are likely to develop around/after 12z as that flow replenishes sfc moisture and instability is realized, even if only as stratocu initially. Deep convection is possible as soon as mid-morning but more likely in the afternoon nearer axis of synoptic shortwave. Hence precip impacts are handled with PROB30s in the morning and TEMPO TSRA in the aftn. Any TSRA will be capable of torrential rain and so did not shy away from IFR vsby/cigs therein. Winds generally will remain southerly. Outlook: Enhanced moisture will combine with a weak/stalled front through early next week, resulting in a period of active/mainly diurnal convective weather each day. There will also be the potential for restrictions associated with widespread fog and/or low clouds each morning. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...RWH/Wimberley SHORT TERM...PM LONG TERM...PM AVIATION...Wimberley