Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/27/20

National Weather Service Albany NY
1026 PM EDT Sun Apr 26 2020 .SYNOPSIS... A low pressure system will slowly track northeast to south of Long Island overnight. This system will continue to bring widespread rain for valley locations and either snow or a rain/snow mix to the higher terrain. Cloudy, cool, and damp conditions with valley rain and mountain rain/snow showers will persist through Monday, as low pressure gradually tracks just southeast of Cape Cod. Drying is expected by Tuesday, as low pressure finally moves farther away from our region and a small area of high pressure builds in from the west. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Winter Weather Advisory now in effect until 5 am EDT MON for northern Warren County... Winter Weather Advisory in effect until 5 am EDT MON for Schoharie County... Winter Weather Advisory in effect until noon Monday for the southern Greens of Bennington and western Windham Counties... As of 1026 PM EDT...A persistent mesoscale snowband has continued to impact portions of the northern Lake George Region, northwest Saratoga Region, eastern Adirondacks, the west central Mohawk Valley, northern Catskills and the Schoharie Valley. We had a report of 4" in Bakers Mills/Johnsburg and snow will continue to persist at least through midnight. We placed northern Warren Co. into a Winter Wx Advisory. Total accums of 2-6" are possible across the higher terrain of Warren County. We are thinking 1-2" is possible in portions of the western and central Mohawk Valley, except we have had some reports in extreme southwest Montgomery county closer to 1000 ft of 5". Therefore, some isolated higher amounts are possible. We still have totals of 3-7" are likely in Schoharie County. 2-5" in the southern Adirondacks foothills /northern Fulton Co./ and southern Hamilton County, and the eastern Catskills. The activity south and east of the mesoscale band has been intermittent and showery with a dry slot between the coastal wave south of Long Island and the primary wave over the Mason Dixon Line evident on the GOES-16 water vapor imagery. Again, the heavy pcpn rates combined with wet bulb/dynamical cooling from the mesoscale band caused the light to moderate snow tallies in the west-central Mohawk/northern and eastern Catskills, foothills of the southern Adirondacks, the Lake George northern Saratoga Region. The mesoscale snowband is tied to area of low to mid level frontogenesis /H850-H700 layer/ that will continue to weaken based on the 3-km HRRR over the next few hours. There is slight a chance southern VT above 1500 ft could get a quick burst of 2-6" of snow above 1500 feet, so we will leave the Advisory going there. SLR continued around 4:1 to 7:1 in the higher terrain, which will be a wet consistency. Snow may mix in down to around 1000 ft with a coasting to perhaps an inch or so in some spots. Valley locations will likely just see plain rain tonight outside of the western and central Mohawk Valley. Some breaks in the precip may occur after midnight, as the coastal cyclone tracks southeast of Cape Cod. Still, most areas north of Albany will at least experience occasional precip much of the night. Northeast winds will become quite gusty across the favored higher terrain areas of the southern Greens and Berkshire, as low level winds increase and peak overnight. Will continue to mention gusts of 30-40 mph in these areas, with generally 20-30 mph gusts elsewhere. Low temps will be mainly in the 30s, with some upper 20s on the mountain peaks. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... The surface cyclone will continue to track northeastward from a position just south and east of Cape Cod on Monday. The upper level pattern will be rather chaotic, with a large closed circulation over the region, with several short waves rotating around the main gyre. Relatively steady precip (rain/snow) will occur over most higher terrain areas, with rain likely in the valleys. Thermal profiles should be slightly "warmer", as the forcing and precip rates will be weaker. So not much additional snow accumulation is expected at elevations below 1500 ft. By afternoon, any accumulations should be confined to the mountain peaks. It will remain cloudy/cool through the day, with highs only in the mid/upper 40s in valleys and mid/upper 30s in the higher terrain. Winds will shift to the north. Some lingering light rain/snow showers will be possible Monday evening associated with a weakening trough axis and wrap-around moisture, but the bulk of the precip will finally start to diminish. The upper trough starts to shear out, while a small surface ridge builds in late Monday night into Tuesday morning. Temps will remain below normal. Drying conditions in store for Tuesday, as the surface ridge moves across the region, with a light northwest flow. There should be at least a mix of sunshine and clouds for much of the day, so temps will respond by warming well into the 50s in valley locations. Upper level ridging will develop Tuesday night, which will keep dry conditions in place. The air mass will remain cool, with low temps in the upper 20s to upper 30s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Upper level ridging will be departing to the east on Wednesday as a large upper level low over the Midwest starts to approach. Although the morning will start off dry and quiet, sky cover will be quickly increasing on Wednesday. There continues to be some uncertainty regarding the exact speed of this system and when some initial warm advection precip may begin across the area. Although we do have some CHC POPs for western areas by afternoon, it may take until Wed evening or night for rain to begin across the entire area. Temps will be a little below normal, but still comfortable, with valley highs well into the 50s. With a strong southerly low-level jet (about 50 kts at 850 hpa) ahead of the advancing storm system, there should be a period of steady rainfall, most likely for some point between late Wed night through Thursday evening. Some moderate to locally heavy rainfall can`t be ruled out, especially across the higher elevations, where upslope flow will enhance rainfall. With plenty of mild air, both at the surface and aloft, p-type will be all plain rain. Daytime temps should be in the 50s for most spots, with upper 30s to mid 40s at night. As the best isentropic lift shifts away, the steadiest rainfall will end for later in the week. However, plenty of lingering clouds and showers will continue for Thursday night through Friday, as the slow moving upper level low passes over the region and cyclonic flow remains in place. Will keep POPs fairly high for Thursday night into Friday with more rain showers. Lingering clouds and a shower or two may continue into Saturday morning, otherwise, gradual clearing is expected by Saturday afternoon as the upper level disturbance moves away and drier air works into the region. Still some uncertainty for the remainder of the weekend with zonal flow in place, so will keep some low POPs in place. With some sun returning and milder temps aloft, max temps look to be in the mid 50s to mid 60s across the region, with overnight lows in the 40s. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... A secondary low pressure system will move from coastal southern NJ this evening to near Cape Cod by daybreak tomorrow, and then move slowly east to northeast towards Nova Scotia during the afternoon. Expect cigs/vsbys to continue to fall to MVFR levels at KGFL/KALB/KPSF/KPOU early this evening with periods of rain. The cigs/vsbys may briefly lower to IFR levels at KPOU/KPSF/KGFL prior to 06Z/MON. For KALB, we have kept cigs/vsbys mainly MVFR until close to 08Z/MON when some IFR cigs may develop. Some snow may briefly mix with the rain at KPSF overnight. Widespread low MVFR/IFR conditions are likely prior 12Z-14Z/MON, until the pcpn lets up and maybe spotty. We could even see a brief lull in the rain or shower activity until noon or so. We tried to raise conditions to MVFR levels in the late morning or early pm. Some rain or showers will redevelop due to the upper low and the coastal cyclone slowly moving northeast of Cape Cod. We maintained cigs 1.5-2.5 kft AGL in the afternoon with vsbys in the 4-6SM range. The winds will be north to northeast at 8-15 kts tonight with some gusts 20-25 kts at KALB/KPSF/KGFL. The winds will continue to be northerly at 8-13 kts during the late morning into the afternoon with some gusts around 20 kts. Outlook... Monday Night: Moderate Operational Impact. Chance of SHRA. Tuesday: Low Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: Moderate Operational Impact. Chance of SHRA. Wednesday Night: High Operational Impact. Definite SHRA. Thursday: High Operational Impact. Breezy. Definite RA. Thursday Night: High Operational Impact. Definite SHRA. Friday: High Operational Impact. Likely SHRA. && .FIRE WEATHER... A low pressure system will slowly track eastward across the Middle Atlantic region into this evening, before emerging off the New Jersey coast tonight. This system will bring widespread rain for valley locations and either snow or a rain/snow mix to the higher terrain. Cloudy, cool, and damp conditions with valley rain and mountain rain/snow showers will persist through Monday, as low pressure gradually tracks just southeast of Cape Cod. Drying is expected by Tuesday, as low pressure finally moves farther away from our region and a small area of high pressure builds in from the west. Relative humidity will increase to around 90 to 100 percent tonight, and will only drop to around 70 to 85 percent on Monday with cool/damp conditions persisting. Relative humidity will increase to between 80 and 95 percent Monday night. Winds tonight will be northeast around 10 to 20 mph, with some gusts of 30 to 40 mph in the higher terrain of the southern Green mountains and Berkshires. Winds on Monday will be northerly around 10 to 15 mph, becoming northwest at 5 to 10 mph Monday night. && .HYDROLOGY... Two storm systems are expected to bring widespread precipitation to eastern NY and western New England this week. The first will be a long duration event with widespread rain this afternoon into tonight. Rain will change to accumulating snow for elevations above 1500 ft. Rain showers and rain/snow mix in the higher terrain continue into Monday. Total precipitation for this event will range between 0.75 and 1.50 inches. Whiles rivers rises will occur, flooding is not anticipated at this time. After a brief break for dry weather mid-week, a moisture-rich system will bring another long duration event to eastern NY and western New England Thursday into Friday. Guidance continues to signal that the system will pump a plume of moisture out of the Gulf of Mexico and the Atlantic and direct it into the Northeast, leading to a period of steady (perhaps heavy) rainfall during this time. Widespread rainfall amounts of 1 to 2 inches are possible with locally higher amounts due to terrain enhancements and instability. Given that soils will likely already be relatively saturated from the earlier event, rivers should respond once again. Current MMEFS indicates some river points may approach minor flood stage later this week, but there is a low confidence for any river flooding at this time. Will have more specifics as the la For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...Winter Weather Advisory until 5 AM EDT Monday for NYZ042-047. MA...None. VT...Winter Weather Advisory until noon EDT Monday for VTZ013-014. && $$ SYNOPSIS...JPV/Wasula NEAR TERM...JPV/Wasula SHORT TERM...JPV LONG TERM...Frugis AVIATION...Wasula FIRE WEATHER...JPV HYDROLOGY...JPV/Speciale
National Weather Service Kansas City/Pleasant Hill MO
648 PM CDT Sun Apr 26 2020 .Discussion... Issued at 245 PM CDT SUN APR 26 2020 Surface ridge solidly in place over the forecast area through the first half of Sunday, going into the afternoon and evening hours. This has caused very light and somewhat variable winds across the area with ample sunshine. Slowly, but surely that ridge will continue its trek eastward, allowing for southerly return flow into the immediate area. Expect southwest winds to prevail going into the evening and overnight hours tonight. The bigger forecast concern for the next 12-24 hours will be the prospects for at least scattered, if not widespread showers later tonight. The mechanism for the thunderstorm activity tonight is apparent on radar across eastern Kansas and western Missouri, where decent isentropic ascent along the 300 and 305K surface are providing just enough ascent to form some clouds and some high-elevation showers. Forecast soundings indicate a very dry layer of air blow the cloud bearing layer where the light precipitation is being formed. While it`s not completely inconceivable that some rain drops survive that dry layer below 10 kft most will evaporate, so accumulating rain is not likely through the remainder of the daytime hours. That may change as we go into the overnight period, as the isentropic ascent becomes a little more pronounced as a low level jet noses in. With not much antecedent moisture to work with, main source of moisture will be whatever advects into the area within that low level jet regime. This will severely limit the MU CAPE to at most 500 J/kg. Despite ample shear the instability should be modest enough to keep any of the elevated showers overnight sub-severe. While Hi-res models, namely the HRRR seems to indicate most of the convection to occur just east of the KC Metro, it`s very possible that with the better lift around or maybe even just west of the KC metro that there could be some of those scattered storms over the metro tonight with some rumbles of thunder possible through the morning hours. For Monday, clouds may stick around for most of the day, as the cloud debris from the overnight activity slowly clears out. The clouds may be reinforced by a shortwave trough gliding through the area during the mid to late morning hours. Despite the cloudiness, temperatures on Monday should remain nice and warm with the southerly winds advect warmer/moister air into the area. Much uncertainty still clouds over the potential for strong to severe storms on Tuesday. Synoptic scale operational models have indicated an early arrival of a cold front impacting a deep warm sector on Tuesday. It`s possible this cold front will arrive a bit later in the day, in which case even 6 hours later would result in more destabilization and a more northward/westward expansion of the impacts of these potentially strong storms. Latest run of the NAM does hint at that being the case as it`s cold frontal position at 18z on Tuesday is currently west of the forecast area, indicating a push through the area at a more prime time for potentially severe weather. The 12z ECMWF appears to be following suit, so Tuesday will still need to be watched for a more organized severe weather day for at least a portion of the forecast area if not the entire forecast area, including the KC Metro. Cold front passes through the area by Wednesday, making for what should be a quiet Wednesday and Thursday. Northwest winds on Wednesday may be rather gusty, depending on how deep we can mix, there would be a chance to see some 30 to 40+ mph surface winds on Wednesday as the surface ridge moves in. Beyond that time period, going into the late part of next week there is some support for a reloading warm sector into the forecast area. That may portend perhaps an uptick in convective weather going into the extended forecast period. && .Aviation...(For the 00Z TAFS through 00Z Monday Evening) Issued at 638 PM CDT SUN APR 26 2020 High based showers are currently moving through eastern Kansas and western Missouri early this period. Little if any rain is making it to the surface and much of the activity will remain virga due to much drier air near the surface. The 850mb low level jet will increase this evening resulting in the development of scattered showers and thunderstorms from about 06-12Z, but may continue through 15Z. A shortwave trough moves through during the early afternoon hours, but the bulk of the precipitation from this wave is expected to stay south of the terminals. Southerly winds will pick up after 12Z and could see some gusty of 20-25 kt from mid to late morning continuing into early afternoon. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ Discussion...Leighton Aviation...Pietrycha
Area Forecast Discussion
National Weather Service Grand Forks ND
953 PM CDT Sun Apr 26 2020 .UPDATE... Issued at 953 PM CDT Sun Apr 26 2020 Seeing an uptick in moderate radar returns over eastern ND as activity spreads east, with a couple lighting flashes picked up by GLM just southwest of our CWA. Activity remains scattered, and outside of where 35-45 dbz returns are most activity had been virga due to a good sub cloud dry layer in place across our region. Upstream trends to the west indicate weakening, with a potential subsident axis on satellite likely associated with PV anomaly immediately behind trough axis. We still expect scattered showers/isolated storms to track east with activity diminishing in eastern ND around midnight, and possibly increasing in coverage ahead of trough axis in north central MN. Amounts have been enough to wet surfaces, but overall no any major impacts. Could see potential for 0.1-0.25 in northwest MN before it exits at daybreak. UPDATE Issued at 656 PM CDT Sun Apr 26 2020 Returns on radar would indicate numerous light rain showers, however most basins are high and there are only a few pockets where rain is reaching the surface in our area. There is still instability show on RAP analysis (MUCAPE around 250 J/KG), but so far most lighting activity has remains well north of the International Border. CAMs (and forecast) timing matches well with current radar returns, however it may be overdone regarding actual threat of measurable precip early this evening. As this activity spreads east tonight there is still an indication that it will pick up in intensity with measurable chances increasing in north central MN. For now I made adjustments to near term timing, but held off on more substantial chance beyond that. && .SHORT TERM...(This evening through Monday) Issued at 307 PM CDT Sun Apr 26 2020 Little impacts wrt to the weather in the short term. Frontal passage this evening will bring some scattered shower activity to the area with possibly some embedded thunder with MUCAPE up to 500 J/kg. Model solns continue to depict coverage increasing as the precip moves into the MN portions of the area this evening and into the overnight. Amounts will be on the light side with up to a tenth of an inch or so with the heaviest showers. Also expecting some evaporation with dry near surface layer causing some virga. Monday will see west winds develop behind the front and sunny skies allowing for temps to reach into the mid and upper 60s. A few locations may see their first 70 degree day of the warm season as the quick moving surface ridge axis pushes across the northern plains. .LONG TERM...(Monday night through Sunday) Issued at 307 PM CDT Sun Apr 26 2020 This forecast period will be active with multiple upper waves moving through or near the Northern Plains. The first wave will lead to rain chances Monday night into Tuesday night. The main source of lift will be a surface low passing to the south across northern Iowa or southern Minnesota. For this reason the highest rain totals are expected over southeast North Dakota and west central Minnesota. Some instability may also be present in this same area to allow for thunderstorms. Instability will not be high enough and there is not likely to be enough shear for strong to severe storms in this area with CAPE under 500 J/kg and bulk shear under 20 knots. The confidence in rain is high, but the exact amounts are still somewhat uncertain due to spread in both ensemble and deterministic guidance. A break in the activity for Wednesday and Thursday with only a few rain showers possible. Friday looks likely to be the warmest day of the year so far with high temperatures in low to mid 70s for most, some upper 60s still more likely in north central Minnesota. With this heat comes more potential for CAPE, but a relatively dry environment looks to keep LCLs high and CAPE values low. There is a fair to moderate amount of shear around, but with out much instability strong storms are not as likely to form. If there is a chance something could form it would be along the front moving across the Northern Plains late Friday. A period of ridging looks most likely for the next weekend leader to quieter weather. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 656 PM CDT Sun Apr 26 2020 VFR conditions are expected to prevail through the TAF period across eastern ND and northwest MN, with main aviation impact from showers moving west to east across the region. We also can`t rule out an isolated thunderstorm, but so far coverage looks to be very low/threat minimal. Southerly winds 10-15kt should continue to decrease and eventually shift to the west late tonight/Monday morning remaining near or below 10kt for most locations. A few daytime gusts to 20kt can`t be ruled out Monday (mainly north of Highway 2). && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. River point flood warnings continue across portions of the region. Refer to the latest flood warnings and statements for detailed information on specific locations. && $$ UPDATE...DJR SHORT TERM...JK LONG TERM...NC AVIATION...DJR