####018004024#### FXUS61 KCAR 260904 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 504 AM EDT Fri Apr 26 2024 .SYNOPSIS... High pressure will cross the region today into Saturday then slowly exit to the east later Saturday into Sunday. A warm front will cross the region Sunday. A cold front will cross the region later Sunday into Monday. Low pressure will approach from the west Tuesday. && .NEAR TERM /THROUGH TONIGHT/... Surface high pressure will cross the region today through tonight. Aloft, an upper trof will exit across the Maritimes today with ridging then building toward the region tonight. Across northern areas, expect mostly sunny skies this morning then mostly/partly sunny this afternoon with limited diurnal cloud development. Across Downeast areas, expect mostly sunny skies today. Expect mostly clear skies across the entire forecast area tonight. High temperatures today will range from the upper 40s to around 50 north, to the lower to mid 50s Downeast. An afternoon sea breeze will likely develop along the Downeast coast. Low temperatures tonight will range from the lower to mid 20s north, to the mid 20s to around 30 Downeast. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... Mid/upper level ridging builds in on Saturday as surface high shifts east. Dry air through the column sets the stage for another mainly sunny day, except for some increasing high level cloudiness by afternoon. Highs Saturday afternoon will climb into the lower 60s for most areas, except onshore flow will keep things cooler for Downeast, especially the coast. Weak warm front approaches Saturday night with increasing mid/high level cloudiness, although it should remain mainly dry Saturday night. Lows Saturday night will fall into the mid to upper 30s. Models are in somewhat better agreement by Sunday that an approaching weakening short wave/cold front will bring a few showers into far northern portions of the region during Sunday afternoon. Afternoon highs on Sunday will top out in the lower 60s for most areas, except cooler along the coast. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... A weak cold front will cross the region Sunday night, with a lingering evening shower possible, mainly for northern and eastern portions of the area. Surface high pressure over Quebec province will briefly ridge across northern Maine later Sunday night into Monday, with dry conditions. Low pressure will track to the north of the Great Lakes Monday night and Tuesday. Moisture will begin to increase along a frontal boundary to our west later Monday night and Tuesday. This will bring the chance for showers Tuesday and Tuesday night. Looks like upper ridge may build back by mid week with a possible trend toward drier conditions. Another weak system could bring more showers by late next week. Afternoon highs are expected to be a bit above normal Monday, near to a bit below normal Tuesday and Wednesday, and then above by Thursday. && .AVIATION /09Z FRIDAY THROUGH TUESDAY/... NEAR TERM: VFR conditions expected today through tonight. Northwest/north winds around 10 knots today, except becoming onshore along the Downeast coast this afternoon. Light and variable winds tonight. SHORT TERM: Saturday and Saturday night...VFR. Sunday-Sunday night...MVFR/VFR. Scattered showers possible Aroostook terminals. Monday and Monday night...VFR. N wind G15-20 kt possible Monday. Tuesday...MVFR. Scattered showers. && .MARINE... NEAR TERM: Winds/seas below small craft advisory levels today through tonight. SHORT TERM: Winds/seas are expected to be belows SCA levels through the period. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...Norcross Short Term...TWD Long Term...TWD Aviation...Norcross/TWD Marine...Norcross/TWD ####018005847#### FXUS65 KBYZ 260907 AFDBYZ Area Forecast Discussion National Weather Service Billings MT 307 AM MDT Fri Apr 26 2024 .DISCUSSION... Through Saturday... Satellite imagery shows a fairly complex picture over the western CONUS. A dynamic low is exiting the central Rockies and moving into the central plains. An upstream trof is digging thru the PacNW toward the great basin...a feature that will reach CO Saturday. The storm track favors weak flow aloft in our region and is less supportive of meaningful precipitation over the next couple of days. The forecast continues to trend drier. Mountain snow: A winter storm warning is in effect thru Saturday night for the Beartooth-Absaroka and Crazy Mountains, and will make no changes at this time. Fisher Creek Snotel (near Cooke City) has seen 0.60" of SWE over the past 24hrs. Additional snowfall should range from 6 to 14 inches, greatest on east aspects above 8000 feet. As heights slowly rise between the two aforementioned lows, a drier northeast flow is expected to persist through eastern MT toward north central WY. As a result, snowfall for the Bighorns looks to be less than previously thought (1 to 5" above 8000 feet), and have cancelled the winter weather advisory here. Rain showers: The trof digging to our west will be associated with mid level winds turning easterly today. Greatest moisture and steepest mid level lapse rates will exist over our west, and this combined with the upsloping will yield greatest precip amounts over western mountains and foothills (0.30-0.80" by Saturday). Over the 6 hours ending at 2am, the Beartooth-Absarokas picked up anywhere from 0.05-0.20" of precip. At 245am, pockets of showers were developing near Roundup, Hysham and Billings as well. Further east, as already mentioned, a drier northeast flow will keep the east half of our cwa mostly dry. Axis of instability this afternoon looks to exist in the western Dakotas, so t-storm potential is mostly to our east today, but could see a late day cell or two near the Dakotas border. Temperatures today and Saturday will be seasonable. Look for highs ranging from the lower 50s to near 70F today (coolest west) then mid 50s to mid 60s tomorrow. A couple noteworthy probabilities: 0.50" of precip: 75% western mtns, 35% fthls, <5% elsewhere 6" snow: 80% western mountains, 5% or less Bighorns JKL Saturday evening through Friday... Weak and brief ridging will begin filling into the region Saturday night, lasting into Monday morning. Lingering precipitation with the deep low in the Plains will result in a few more inches of snow accumulations in the higher elevations, above 7000ft, of the western mountains. Precip chances will be highest from Sheridan to Roundup and west Sunday into Monday, with the mountains seeing moderate to high chances, greater than 60%. Lower elevations will see low to moderate chances, 25-60%, with precip type being all rain. The brief ridging will break down as a cold front associated with a splitting low and trough in southern Canada, moves through the state Monday afternoon. Ample moisture and precip chances will accompany this front, precip chances will be more widespread than over the weekend, increasing from the west to the east. Moderate to high chances (45-90%) are forecasted across the area through Monday night, with the mountains having the highest probabilities. The probability for a tenth of an inch of QPF is 30-60% east of Billings and 60-85% west of Billings. The probability of a quarter of an inch or more of QPF is 10-30% east of Billings and 40-70% in the western mtns and foothills. The higher peaks of the Bighorns have up to a 50% chance of seeing 0.25" of QPF. Tuesday, zonal flow and ridging will settle into the northern Rockies, persisting into the latter half of the week. Lingering chances for precip will remain through at least Wednesday, with 10-40% probabilities in the forecast. Rising heights will bring warmer temperatures, with highs in the 60s Tuesday and Wednesday, and climbing into the 70s to end the week. Matos && .AVIATION... Periodic showers with areas of MVFR and local IFR will impact locations close to the mountains & foothills today and tonight. Greatest potential for sub-VFR is west of KBIL. Mountains will be frequently obscured in snow. There is also potential for localized fog in far southeast MT early this morning, until about 15z. Fog could impact KBHK & K97M. Otherwise, VFR should prevail from KBIL eastward. JKL && .PRELIMINARY POINT TEMP/POPS... Tdy Sat Sun Mon Tue Wed Thu ------------------------------------------------------- BIL 062 043/063 042/064 044/066 038/061 038/064 039/073 5/W 32/W 14/W 26/T 63/W 23/W 12/W LVM 053 040/058 042/060 040/058 032/056 032/060 035/069 9/W 96/W 56/W 38/T 64/W 23/T 12/W HDN 068 041/065 041/065 041/068 038/063 036/066 039/076 3/W 31/B 13/W 25/T 73/W 22/W 12/W MLS 070 040/063 039/060 037/066 040/060 037/063 041/072 1/N 10/B 01/B 02/W 61/N 22/W 11/B 4BQ 069 042/060 039/058 037/067 040/061 037/064 041/072 2/W 21/B 11/B 02/W 42/W 22/W 11/U BHK 067 038/058 034/052 032/065 037/059 033/061 036/064 2/W 21/B 12/W 01/U 52/W 22/W 12/W SHR 062 040/060 035/060 037/066 035/061 034/063 038/072 4/W 54/W 24/W 13/W 63/W 32/T 22/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Storm Warning remains in effect until 6 AM MDT Sunday FOR ZONES 67-68. && $$ weather.gov/billings ####018006384#### FXUS63 KILX 260908 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 408 AM CDT Fri Apr 26 2024 .KEY MESSAGES... - There will be multiple rounds of showers and thunderstorms today through Monday. Some of the storms could be strong to severe through Sunday (5-15%). Much of the area can expect over 1 inch of rain (50th percentile) through Monday, but localized amounts in the 1.5 to 2 inch amounts are possible particularly west of the Illinois River. - Warmer and more humid conditions and windy conditions are expected this weekend. Daily highs will be in the upper 70s and lower 80s accompanied by breezy southerly winds gusting 30 to 40 mph at times. && .DISCUSSION... Issued at 355 AM CDT Fri Apr 26 2024 Predawn surface map shows 993 mb low pressure over nw KS with its warm front over northeast KS into sw MO and central AR. 1032 mb Canadian high pressure was near Montreal close to the the southern Quebec/Ontario province border and ridging westward over the Great Lakes. An east to ESE flow around this high pressure over CWA was keeping lower dewpoints in the mid 30s to around 40F, with even lower 30s over Lacon, Pontiac and LaSalle/Peru. Not as cool as last night with temps in the mid 40s to upper 40s in central IL and lower 50s in southeast IL. Radar mosaic shows widespread showers and scattered thunderstorms over central and western parts of MO/IA with stronger southerly low level jet west of IL. Also some scattered showers in southern IL south of I-64 and into sw KY and mid TN. A 925-850 mb warm front to lift ne over central IL during this morning and early afternoon, with a band of showers and isolated thunderstorms lifting ne over CWA. Showers to reach far sw CWA by Scott county around or just after sunrise and to the Indiana border by 17Z/noon. Then another wave of showers and a few thunderstorms to move eastward into central IL during this afternoon, especially west of I-57. Low threat of severe thunderstorms this afternoon as air mass does not get that unstable yet, with the stronger instability poised west of IL today and into tonight where slight to enhanced risk over MO and Iowa. SPC day1 outlook has marginal risk of severe storms over much of central and western IL with 5% risk of large hail and damaging winds for mainly this evening. There is a 2% risk of tornadoes west of a Macomb to Jacksonville line. Highs today range from lower 60s from I-74 north to lower 70s along and south of highway 50 in southeast IL. Breezy SE winds develop today with gusts 25-30 mph likely. Surface low pressure to track ne toward the northern WI and MN border by dawn Saturday, with warm front lifting north of central IL. Low pressure weakens as it moves into eastern Lake Superior by sunset Saturday, while pushing a cold front through central parts of WI/Iowa. Looks like a lull in convection over central/se IL Saturday morning, but a more unstable air mass develops by Saturday afternoon of 1500-2500 j/kg Saturday afternoon, most unstable western/nw CWA where wind shear values nearing 30 kts. SPC day2 outlook continues slight risk of severe storms along and nw of the IL river Sat afternoon/evening while marginal risk extends as far se as a Danville to Sullivan to Litchfield line. Main severe wx threats are damaging winds and large hail while 2-5% risk of tornadoes from the IL river west. Greater threat of severe storms Sat and Sat night will still west of IL closer to frontal boundary. Stronger southerly winds develop in warm sector over CWA on Saturday with gusts 30-40 mph and bringing warmer highs in the upper 70s and lower 80s. More humid as well with dewpoints getting into the mid 60s. Another surface low pressure develops in southeast CO Sat afternoon and eject ne toward the upper MS river valley late Sunday night. This to bring another round of showers and thunderstorms Sunday afternoon and Sunday night. SPC day3 outlook has marginal to slight risk of severe storms over all but far eastern IL during this period, with the slight risk west of Peoria and Springfield. Cold front to push eastward over IL during Monday and likely continues chances of showers and thunderstorms though weaker instability on Monday so lower threat of severe storms than this weekend. Rainfall amounts over 1 inch over much of CWA today through Monday with locally 1.5-2 inch amounts over areas west of the IL river as PW values will be around 1.5 inches at times. Though any training of thunderstorms could bring over 2 inch amounts of rainfall. Strong southerly winds gusting 30-40 mph on Sunday and even approaching 45 mph north of I-70, with warm highs in the lower 80s with Lawrenceville near 85F. Highs Monday in the mid 70s. Looks like a brief lull in convection chances overnight Monday night into Tuesday, though could be a little more convection developing later Tue with approaching of next wx system into the upper Midwest. Still mild Tue with sw breezes with highs in the upper 70s to near 80F. Next chance of showers and thunderstorms to be later Wed into Thursday and Wed night as yet another wx system moves over the upper MS river valley and pushing a front into IL. Highs in the upper 70s to around 80F again on Wed and in the low to mid 70s Thu. 07 && .AVIATION... (For the 06z TAFs through 06z Friday Night) Issued at 1025 PM CDT Thu Apr 25 2024 High pressure over the eastern Great Lakes will shift east tonight, as low pressure moves into the western Plains. This will keep east-southeast winds blowing around 10-12 kt overnight, then gust 20-25 kt on Friday when the gradient tightens. Mainly high cirrus in place through much of tonight, then lowering cloud bases after sunrise with the approach of a warm front. Ahead of the front, a band of showers is likely to affect all terminals late morning through much of the afternoon, producing MVFR ceiling and visibility. Showers should scatter out late afternoon, and with low confidence on clearing trends into the evening kept BKN MVFR ceilings in the forecast. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$ ####018004412#### FXUS63 KTOP 260909 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 409 AM CDT Fri Apr 26 2024 .KEY MESSAGES... -Two separate storm systems bring several rounds of thunderstorms to the area through the weekend. -Large hail, strong damaging winds and tornadoes are all possible this afternoon in far eastern KS, and again Saturday. -Multiple rounds of rain could also lead to localized flooding. && .DISCUSSION... Issued at 404 AM CDT Fri Apr 26 2024 Early this morning, a 50 kt LLJ is in place over eastern KS ahead of a deepening mid-level storm system that is ejecting out over the High Plains of Nebraska/Kansas. The surface low is over far western KS with a warm front extending east/southeast through southern KS. Dew points south of the warm front are in the mid to upper 60s. The warm sector of the system will continue to advance northward through the area this morning as the warm front passes to the north. Instability will build to over 2500 J/kg of SBCAPE with steep mid-level lapse rates between 7-7.5 C/km in place across eastern KS by mid-afternoon. Strong wind fields east of the upper low will lead to sufficient deep layer shear for severe weather, while 0-3km SRH values ranging from 150-200 m2/s2 point to a tornadic potential. Thus, all modes of severe weather will be possible with any supercell development east of the dryline this afternoon. Some CAMs hint at isolated to widely scattered convective initiation as early as 20Z, with storms exiting to the east by around 01Z. A period of dry weather is expected tonight as the first system moves northeast into the Upper Midwest. In the meantime, a second system will dig over the desert southwest, inducing surface cyclogenesis in southwest KS. Central and eastern KS will remain in the warm sector with a surface boundary northwest of the area. The setup Saturday still appears to have better potential for a round of significant and widespread severe weather impacting the area. HREF shows average SBCAPE in excess of 3000 J/kg and 0-3km SRH between 100 and 200 m2/s2. A complex of storms looks to develop south of the area during the afternoon and move northward as the upper level jet and large scale forcing increases. Once again, given the impressive shear and instability parameters, all modes of severe weather (very large hail, damaging wind and tornadoes) will be possible. Heavy rainfall could also occur, leading to localized flooding, especially where grounds were recently saturated by heavy rain from Anderson County northwest through Cloud County. The convective complex looks to slowly work eastward with time, while continuing into the overnight period. Yet another round of severe weather looks possible Sunday afternoon in eastern portions of KS with the main trough axis and surface cold front still just west of the area. A little more uncertainty exists with this round, which will be partially dependent on how much destabilization can occur following previous heavy thunderstorm activity and lingering cloud cover. Some models, however, show enough deep layer shear to support rotating updrafts with any storms that manage to develop before the front pushes through the area Sunday night. Following these several rounds of active and potentially impactful weather, a much needed stretch of quite weather is then anticipated to begin the next workweek. NBM has POPs increasing once again by midweek when our next cold front could approach the region. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1236 AM CDT Fri Apr 26 2024 Rain showers and isolated thunderstorms could impact TOP sites early this period before a stretch of dry weather is expected through midday Friday. IFR ceilings are forecast tonight through late morning Friday. VFR is expected to return by early afternoon at all airport. Wind remains a concern as south- southeast winds stay gusty much of the night and increase further after sunrise, gusting over 30 kts at times. Isolated to widely-scattered strong storms could then develop near KTOP/KFOE after 22Z. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Teefey AVIATION...Teefey