Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/02/21

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
555 PM MDT Wed Sep 1 2021 .AVIATION... 00Z TAF CYCLE Showers and embedded thunderstorms will continue through the evening, then slowly dissipate after 06Z. Isolated showers may linger through 12Z. Periods of MVFR conditions and mountain obscurations are likely with the heavier downpours. Low clouds and fog are possible later tonight/Thursday morning between 09Z and 15Z, with the best chances being at KFMN and KGUP as the sky tries to clear later tonight. Friday`s crop of thunderstorms will favor the south and east, with much less coverage elsewhere as dry air works in from the northwest. && .PREV DISCUSSION...417 PM MDT Wed Sep 1 2021... .UPDATE... Dropped the Flash Flood Watch for west central and southwest portions of the area as the heavier rain has moved east of the watch area and little to no redevelopment is expected. The watch continues for the northern mountains. && .PREV DISCUSSION...212 PM MDT Wed Sep 1 2021... .SYNOPSIS... After a fairly wet period through tonight with numerous showers and scattered thunderstorms, some producing heavy rainfall, a return to more normal late Monsoon season conditions is forecast from the end of the work week through the weekend. High pressure will dominate the region next week, with temperatures trending above normal and daily rounds of showers and storms trending down. && .DISCUSSION... SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)... Showers and thunderstorms have been ongoing west of the central mountain chain, with some activity beginning across the eastern plains. ABQ`s 12z sounding showed PWAT at 1.06" (within the 90th percentile). The daily record for Sept 1st is likely to be broken, as tropical moisture from remnants of Hurricane Nora continues to filter in. A weak disturbance crossing to the north will also aid in lift for these storms. A few stronger storms may be possible across the eastern plains, with MLCAPE ranging from 500-1000 J/kg, as this morning`s partly cloudy skies allowed for heating and destabilization. Elsewhere across western and central NM, it`s been mainly stratiform rain up to this point, with the cooler temperatures and cloud cover putting a damper on destabilization. The HRRR and HREF show several rounds of precipitation continuing through the evening, particularly across the Luna and Medio fire burn scar areas. At this time decided not to include the south central mountains in the Flash Flood Watch as the event is already unfolding, but the issuance of Flood Advisories in the area are likely especially after heavy rainfall several days prior. Precipitation will taper off across western and central areas this evening, becoming more focused across the eastern plains by late evening. Any remaining convection will shift eastward into TX/OK by early Thursday morning. Left mention of patchy fog in the forecast package across western areas as skies begin to clear out, but some low clouds/fog will be possible across the east as well. The high will remain to our east on Thursday, as it elongates over the Ark-La-Tex region. As drier air filters in, areas across the northwest will miss out on most of the precipitation. Locally heavy rainfall and flash flooding will once again be possible from the south central mountains into the east central plains, with PWAT`s exceeding 1.2-1.5". High temperatures will generally be a few degrees warmer across the state, with the exception being the areas with continued precipitation. LONG TERM...(FRIDAY THROUGH WEDNESDAY)... The upper high will be over the ArkLaTex on Friday and we`ll remain on the periphery of the circulation with a Monsoon moisture plume directly overhead. Given some destabilization from daytime heating, a healthy round of storms is forecast Friday afternoon/evening, with the potential for locally heavy rainfall across the southwest and south central mountains. Same story for Saturday as the upper high begins to establish a second center over the region, but the addition of a backdoor front will increase chances for storms across the northeast and east central plains during the afternoon/evening hours. The upper high is then forecast to build-up over the Great Basin from Sunday through Tuesday and expand over much of the Desert Southwest and southern/central Rockies. This development will lead to a warming/drying trend that will bring above normal daytime temperatures and a gradual downtrend in daily rounds of storms, especially across northern NM. 31/11 && .FIRE WEATHER... As remnant moisture from Hurricane Nora streams into the state, widespread showers and thunderstorms will continue through the evening hours and focus mainly across eastern New Mexico after sunset. Locally higher rainfall amounts of 1" or more will be possible across the the Sangre de Cristos. Drier air will begin filtering into the northern part of the state Thursday and Friday, with the larger wetting footprints focused over south central and eastern New Mexico. Overnight humidity recoveries will be excellent overall. High pressure will shift and build over the Great Basin region late into the weekend and over the Labor Day holiday, decreasing storm coverage and returning temperatures to above normal. Isolated showers and thunderstorms may focus across southern New Mexico during this time. 31 && .ABQ WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch until midnight MDT tonight for the following zones... NMZ210-211-213>215. && $$
National Weather Service Albany NY
1015 PM EDT Wed Sep 1 2021 .SYNOPSIS... Periods of moderate to heavy rain will impact the region from near Interstate 90 southward tonight before ending early tomorrow morning. Rainfall rates exceeding one inch per hour at times will increase the potential for both river and flash flooding. Then, Canadian high pressure takes control of the area resulting in a stretch of dry and fall-like temperatures the rest of the week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... .A Flash Flood Watch remains in effect for the mid-Hudson Valley, Berkshires and Litchfield Hills from until 2 PM tomorrow... .A Flash Flood Watch remains in effect for the Schoharie Valley to portions of the Capital District and into southern Vermont from until 11 AM tomorrow... As of 1015 pm...forecast remains on track with heavier rainfall rates about to move into southern portions of Dutchess and Litchfield Counties. Added slight chance of thunder to Litchfield. Tweaked PoPs but remainder of the forecast remains unchanged. Additional details below. As of 800 pm...the center of the remnants of TC Ida are located near Wilmington, DE. Rainfall associated with isentropic lift/midlevel Fgen continues over much of the region south of a line from Ft. Plain to Glens Falls. The rain shield should likely not expand further north and west than this. Rainfall rates have generally been around 0.2-0.4"/hour over our southern two tiers of counties and should continue to increase over the next several hours. Looking upstream, intense rainfall rates of 1-3"/hour have been observed over portions of eastern PA/northeast NJ. This is associated with intense 1000-925mb Fgen. CAMs in the 18Z HREF suite as well as more recent HRRR runs suggest the 2-3" hour rates remain just south of our CWA border, but the 18Z HREF does have high probabilities of 1"/hr and 3"/3hr scraping southern portions of Dutchess/Litchfield Counties 03-08Z. This is where and when the concern for significant flash flooding is highest. Even outside of this area, flash flooding remains possible as NYSM sites in southern Ulster/Dutchess are already up to 2-3" for the storm total and rates will only continue to increase over the next several hours. It appears we will stay out of the warm sector, so the threat for severe thunderstorms/tornadoes is basically nil. Overall, no meaningful changes needed to the forecast. Previous discussion... As of 5 pm, moderate rain associated with the incoming remnants of Ida has brought about 1 to 1.50 inches of rain to the mid- Hudson Valley, eastern Catskills, and Litchfield County, CT so far today with a rather sharp northward cut-off heading towards I-90 where rain amounts have only accumulated up to 0.25 to 0.50. Areas just north of this interstate have only just started to rainfall over the last hour or two and therefore have only received a few hundredths. With the low now tracking across the Mason Dixon Line towards NYC, its associated warm front is lifting northward which is allowing the area of moderate to heavy rain in the cool air wedge within the deformation zone to push northward as well. As a result, parts of Litchfield County could see rain turn light at times through the evening commute with rain inching into Glens Falls. Even with this northward push, the dry air ahead of the precip shield looks to stand tough and prevent rain from advancing much beyond Warren, Washington County into southern parts of Herkimer and Hamilton County through tonight. Upstream, the strong southerly mid-level jet ahead of the surface with winds ranging 40 - 50kts is pushing through eastern PA and NJ. This has resulted in very high rainfall rates up to 0.50 inch at times. As the low advances towards NYC, such high rainfall rates are expected to spread into our forecast area. The period from 00 UTC (8PM) to 09 UTC (5AM) is still the main window of concern where very high rainfall rates ranging 1 to 2 inches per hour are possible again primarily for the eastern Catskills, mid-Hudson Valley and NW CT. Efficient warm rain process in place combined with high moisture flux in the 925 to 850 hPa layer coincident with strong omega and additional synoptic lift from a favorable 300 hPa jet position, means rates exceeding 2 inches per hour at times is in the realm of possibilities. Such high rainfall rates increase concerns for both flash and river flooding in this region. Total storm total rainfall amounts of 3 to 6 inches is still predicted but isolated higher amounts are possible. 1 to 3 inches is expected from the Capital District into Schoharie County and southern VT. See hydro discussion for more details on river flooding. The one saving grace is convective elements should be at a minimum as our region remains in the cold air wedge ahead of the warm front. Moderate to heavy rain should quickly exit by 06 - 12 UTC from northwest to southeast with most rain out of western New England by the morning commute. In fact, skies should turn clear for areas north and west of the Capital District by sunrise. Winds look to also turn breezy overnight with gusts up to 25 - 30 mph possible and sustained winds reaching up to 10 to 20mph. Areas with especially saturated soils could become more susceptible to smaller/weakened trees falling, mainly in the mid-Hudson Valley, NW CT and eastern Catskills. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... Fall-like temperatures will occur the rest of the week as an upper level trough digs into the Northeast Thursday into Thursday night with Canadian high pressure building at the surface through Friday. The rather tight pressure gradient between the incoming high and departing remnant tropical cyclone will result in breezy conditions tomorrow morning with gusts up to 25mph possible. Northerly flow will usher in cooler and drier Canadian air tomorrow preventing temperatures from warming up too much. Expect highs to only max out in the upper 60s to low 70s with most reaching their respective convective temperature during afternoon peak heating. This will allow morning sunshine to mix in with afternoon fair weather cumulus clouds. Partly cloudy skies stay in place Thursday night as the base of the trough swings through the region. Even still, temperatures should turn cool dropping into the 50s throughout the region with a light breeze still in place. The Northeast will remain under the influence of the upper level trough most of Friday so some cloud coverage looks to linger with even a few isolated showers not ruled out as the upper level cold pool moves overhead. However, skies gradually clear later in the afternoon as high pressure finally takes control. Despite improving conditions late in the day, high temperatures should be well below normal with most only rising into the mid to upper 60s making it feel fall. Skies become clear overnight allowing temperatures to turn quite cool dropping into upper 40s to low 50s. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Closed off upper level low will be exiting eastern New England and moving across Atlantic Canada for Saturday. As this feature departs, rising heights will allow for a weak shortwave ridge to be in place over the area for Saturday. This will result in a partly to mostly sunny sky and seasonable temps, with valley highs in the mid 70s. This shortwave ridging will quickly be departing, as a large upper level trough north of the Great Lakes over Ontario starts moving southeast. This may allow for a few passing light showers and possibly a thunderstorms for late Saturday night into Sunday, mainly for areas north and west of the Capital Region. Temps should be similar to Saturday with valley highs in the mid 70s, although dewpoints will be rising from the 50s into the low to mid 60s by late Sunday. As the upper level disturbance sits and spins across Ontario and Quebec, we will keep slight to low CHC POPs across the area for Monday through Wednesday, especially during the diurnally favored afternoon hours. The best chance may wind up being on Monday ahead of a frontal boundary, but can`t rule it out for Tues/Wed as well. Any precip looks fairly scattered in coverage and mainly brief in duration. Temps will remain seasonable, with valley temps still reaching into the mid 70s for daytime highs. Dewpoints look highest in the low to mid 60s for Monday ahead of the weak boundary and will fall off into the upper 50s for Tues/Wed. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... As of 2330Z Wednesday...Rain shield associated with the remnants of TC Ida continues to envelope most of the area, with KGFL on the outer edge. KGFL expected to remain VFR through the rest of the night as the low levels likely remain unsaturated. Elsewhere, conditions should continue to deteriorate over the next few hours as rain becomes heavier. Worst conditions should exist at KPOU 02-06Z and KPSF 05-08Z where LIFR conditions are possible. Rain will be less heavy at KALB, but an interval of IFR conditions are possible roughly 04-08Z. Conditions should improve fairly quickly as the storm pulls away from west to east especially after 08Z. VFR conditions are expected for much of the daylight hours Thursday with SCT-BKN cu developing in the afternoon. Winds will be from the north to northeast at around 10 kt, with gusts to near 20-25 kt at times at KPSF/KPOU overnight. Winds at 2kft may increase to 40-45 kt 02-12Z at KPOU so LLWS was retained. The winds will become north to northwest at around 10 kt with occasional gusts near 20 kt during the afternoon on Thursday. Outlook... Thursday Night: No Operational Impact. NO SIG WX. Friday: Low Operational Impact. Slight Chance of SHRA. Friday Night: No Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: Moderate Operational Impact. Chance of SHRA. Sunday Night: Moderate Operational Impact. Chance of SHRA. Labor Day: Moderate Operational Impact. Chance of SHRA. && .FIRE WEATHER... Periods of rain, heavy at times, associated with former tropical cyclone Ida will impact eastern New York and western New England through tonight. High pressure builds in tomorrow morning through the afternoon with cooler and drier conditions. Fair and dry weather will continue into Saturday. The RH values will be close to percent tonight, and then lower to 50 to 65 percent Thursday afternoon. The RH values will recover to 90 to 100 percent Friday morning. The winds will be north to northeast at 5 to 15 mph with some gusts 20 to 30 mph south and east of the Capital Region. The winds will be northerly at 5 to 15 mph Thursday afternoon, and will be become light from the northwest at 10 mph or less. && .HYDROLOGY... The period from 8PM to 5AM tonight will likely feature periods of moderate to heavy rain for areas from Interstate 90 southward especially in the mid-Hudson valley, eastern Catskills and Litchfield County, CT. During this window, the remnant low of Ida will track near or just south of NYC with very efficient rainfall processes coincident with strong synoptic forcing which will likely result in high rainfall rates exceeding one to possibly even two inches at times. The latest guidance positions the region of highest 925 - 850 hPa moisture flux overlapping very strong omega just north of the system`s warm front which looks to track across southern New York. There is still some uncertainty on the exact position of these ingredients and should they line up just south of our area, we could miss out on the highest rainfall totals. However, the high resolutions guidance including the 3km NAM, HREF and HRRR still suggest this overlap will track in our southern zones including Litchfield, Ulster and Dutchess county mainly from 8PM to 5AM. With storm total rainfall amounts expected to range 3 to 6 inches (locally higher up to 7 inches possible), both flash and river flooding in this region is expected. The latest guidance from the Northeast River Forecast Center places forecast points along the Esopus, Rondout, Wappinger Creek and the Housatonic River in flood stage. While the current forecast points to most rivers only reaching minor flood stage, a few near moderate flood stage. According to MMEFS this is possible depending on which river basins receive the highest rainfall amounts. 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...Flash Flood Watch through Thursday afternoon for CTZ001-013. NY...Flash Flood Watch through Thursday afternoon for NYZ058>061- 063>066. Flash Flood Watch through Thursday morning for NYZ047-051>054. MA...Flash Flood Watch through Thursday afternoon for MAZ001-025. VT...Flash Flood Watch through Thursday morning for VTZ013>015. && $$ SYNOPSIS...Rathbun/Speciale NEAR TERM...Thompson/Rathbun/Speciale SHORT TERM...Speciale LONG TERM...Frugis AVIATION...Thompson FIRE WEATHER...Wasula HYDROLOGY...Speciale
Area Forecast Discussion
National Weather Service Billings MT
149 PM MDT Wed Sep 1 2021 .DISCUSSION... Tonight through Thursday night... Satellite imagery shows a deep low over southern Alberta, and a moist monsoonal wave lifting thru the 4-corners area. Confluent southwest flow aloft and lee side surface ridging (along with both high cloud and smoke cover for much of our cwa) are limiting surface heating and instability behind last night`s cold front. There were some showers that clipped southern Carter county this morning, otherwise it`s been a dry day. Upstream radar shows some showers from Casper to south of Gillette. The main surge of moisture from the southwest, and thus the heaviest precipitation over the next 24 hours, will be south and east of our forecast area...and of that we have high confidence. There is a weak shortwave lifting out of northern UT and southwest WY that could bring some showers to our far east tonight into Thursday morning. Recent HRRR runs develop some convection near Sheridan and Lame Deer this evening, but feel that there is not enough moisture and instability that far west for showers. Something to watch. Trof over the PacNW will track slowly eastward bringing ascent and a good chance of showers beginning Thursday night. This feature will tap into a little monsoon moisture before it arrives. Temperatures tomorrow will be a few degrees cooler than today, with highs in the upper 60s and 70s. Southwest flow aloft will bring us another day of lofted smoke. Surface winds out of the NE-E should keep lower elevations fairly clear of smoke. JKL Friday through Tuesday... A trough will move through the area on Friday with showers and thunderstorms across the area. Areas near Billings could see around 0.05 inches while areas in the far southeast corner could see upwards of a half inch or more. To the west of Billings will miss out on rain. As the trough shifts to the east, ridging will build over the four corners. This will bring drier and warmer weather concerns back to the southeastern Montana through early next week. It looks like the pattern could change around midweek but it is too early for details. High temperatures will be in the 60s and 70s Friday, warming into the 70s and 80s on Saturday. Sunday into the middle of next week will have temperatures in the 80s. Carrothers && .AVIATION... High cloud cover will continue over much of the area today before clearing out from west to east overnight. Gusty west winds to 20 knots will continue at KLVM through the afternoon. Otherwise, winds remain relatively light throughout the area. There is a slight chance of brief showers in the vicinity of KSHR-KMLS late this evening. While near-surface smoke concentrations remain low, expect reduced slant range visibility due to high smoke concentrations aloft. Behringer && .PRELIMINARY POINT TEMP/POPS... Thu Fri Sat Sun Mon Tue Wed ----------------------------------------------------------- BIL 050/072 050/068 049/081 053/087 056/087 055/085 055/084 00/H 44/W 10/U 00/U 00/U 00/U 01/B LVM 039/074 044/071 043/080 047/086 050/086 050/085 051/084 01/H 33/W 10/U 00/U 00/U 00/B 11/B HDN 049/076 051/068 046/081 049/087 053/087 053/085 054/086 01/H 55/T 10/U 00/U 00/U 00/U 01/B MLS 055/077 052/070 048/078 051/085 054/084 054/084 054/084 11/H 44/W 10/U 00/U 00/U 00/U 00/U 4BQ 057/077 054/066 049/076 051/083 055/083 054/083 054/084 11/H 66/T 20/U 00/U 00/U 00/U 01/U BHK 057/076 050/068 047/076 049/082 053/082 052/081 052/082 22/T 35/W 20/U 00/U 00/U 00/U 00/B SHR 047/077 048/068 044/079 047/086 051/086 051/085 051/086 12/T 56/T 10/U 00/U 00/U 00/U 01/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service Columbia SC
747 PM EDT Wed Sep 1 2021 .SYNOPSIS... A cold front crosses the area from the west tonight. Dry weather will then prevail through the weekend under the influence of high pressure. Small rain chances will return early next week as moisture increases and upper level troughing develops over the eastern US. && .NEAR TERM /TONIGHT/... Radar showing patchy light showers across parts of the northern Midlands, with its development aided by a passing short wave. Drier air aloft farther south should keep the rest of the forecast area rain-free. Showers will then generally be on a diminishing trend through this evening. Drier air will filter into the area tonight in wake of the passing cold front, with dew points falling through the 60s during the overnight hours. Some additional clearing is expected tonight as well. Temperatures should fall to lows in the 65-70 degree range. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... By early Thursday, the trough associated with the remnants of Ida will be crossing the forecast area. A quick shift from southwesterly to north-northwesterly flow aloft and at the surface will occur between 06z and 12z. Strong ridging will fill in behind the trough passage and help drive some very impressive dry air advection all the way down to the Gulf coast. Dew points and PWATs will fall steadily throughout the day Thursday across South Carolina and Georgia, from the mid-upper 60s to the mid 50s and from over 1.5 inches to under 0.75 inches, respectively. Compared to the dry air advection, temperature advection will not be quite as impressive and we will still reach the upper 80s across much of the area thanks to abundant solar heating with limited cloud cover expected. With the dry air in place, Friday morning will likely be our coolest in some time. Exactly how much we cool will primarily depend on whether we can decouple the boundary layer. Winds may remain up enough thanks the pressure gradient along the leading edge of the surface ridging to prevent completely decoupling. Regardless, temperatures Friday morning will fall into the mid or low 60s. The story remains much the same for Friday as the dry air continues to be reinforced with persistent northwest flow aloft and northerlies at the surface. Dew points will bottom out in the upper 40s Friday afternoon with PWATs falling near or below 0.5 inches; NAEFS shows low level moisture and PWATs both in the 1st percentile climatologically for Friday and early Saturday. Winds will gradually weaken throughout the day as the surface ridge sinks a bit south. High temperatures will again be just few degrees below average thanks to ideal solar heating. Radiational cooling Friday night and Saturday morning will be close to maximized with clear skies, light or no winds, and far below average moisture from the surface to upper levels. Guidance is likely under-doing the cooling at this time, but is still showing low 60s everywhere. So given the trends and anomalously dry airmass, lows will likely near 60 or possibly the upper 50s in spots. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... The long term will primarily be a gradual return to more typical early September conditions across the forecast area. Below average surface dew points and PWATs will remain in place Saturday. NAEFS shows near average moisture and temperatures returning by late Sunday. The surface ridge begins to shift offshore by late Saturday, and along with a strengthening trough to our west, allows southerly flow to kick back up across the southeast. This will gradually allow moisture to return and bring back near normal dew points and PWATs by Sunday. All ensemble guidance shows the trough and associated low pressure center to our west swinging up through the northeast by late Sunday. However, the trailing front will weaken and stall before it truly reaches the area as the flow aloft and near the surface becomes nearly uniformly zonal. With the weak forcing, precipitation chances consequently remain only around slight as the front weakens, with only a few members of blend and ensemble guidance showing any accumulation. Ridging to our west then fills in through mid-week and returns near normal temperatures and moisture for early September. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... VFR conditions will remain outside of a brief shower across the Midlands this evening. Otherwise after 03z, vfr conditions everywhere. Narrow band of showers in the northern Midlands is being shown on radar slowly moving southward towards CAE/CUB this evening. There does remain some uncertainty as to whether these will hold together over the next few hours. However the hrrr does show this band passing through CAE/CUB this evening. Timing off of radar doesn`t bring this activity in until near 01z, then passes it through by 03z. Have gone ahead and included vcsh between those hours, with a tempo group for mvfr visibilities in rainfall. Do not think this will hold together as it approaches OGB, so have not mentioned anything there at this time. Outside of these showers, vfr conditions expected, although ceilings will remain broken for a good portion of the night. Skies scatter out Thursday morning as drier air pushes into the region. Winds start off out of the west, then gradually turn northwest, then north through the night. Speeds should remain around 5 knots through the period. EXTENDED AVIATION OUTLOOK...VFR with drier conditions through the weekend. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$