Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/16/24


Area Forecast Discussion
National Weather Service Boston/Norton MA
948 PM EST Thu Feb 15 2024 .SYNOPSIS... High pressure shifts away this afternoon ahead of a clipper system that will bring minor accumulations of snow tonight, especially north of the Mass Pike. Very gusty NW winds behind the clipper system Friday. Coastal low pressure system tacks south of the region on Saturday, but could produce a few snow showers, mainly for the Islands and immediate south coast. Cooler than normal temperatures for both Saturday and Sunday. Dry and seasonable Monday and Tuesday with the potential of more mild weather come midweek. && .NEAR TERM /THROUGH FRIDAY/... 945 PM update... Narrow band of heavier snow racing across eastern MA. RAP snow growth omega is resolving this band fairly well and moves the stronger omega offshore by 11 pm. A few snow showers will briefly linger across northern MA, otherwise mainly dry conditions after midnight. The exception is across the northern Berkshires where some lake effect snow showers may spill into the region. The story then pivots to wind Friday morning as southwesterly winds quickly shift to the NW and cold advection kicks in. This will mean a very well mixed boundary layer up to near 850 mb, able to tap into a 50-60 kt LLJ. BUFKIT forecast soundings indicate a very well mixed boundary layer and steep low level lapse rates which would support wind gusts as high as 45-55+mph. Any wind gusts of this magnitude would be in a short window, generally from 5am to 10am, longer in the Berkshires. The Wind Advisory has been expanded into northern CT and further east in MA. Friday will be sunny, cold, and blustery. The low slowly exits east but the pressure gradient is slow to weaken so winds will be gusting 25 to 35 mph all day. This will make highs in the upper 30s feel more like the upper 20s. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... Quiet Friday night as high pressure approaches from the west. The pressure gradient continues to slacken allowing winds to become light. The colder NW flow will bring lows several degrees colder than the previous night, in the low to mid 20s. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Highlights * Low chance for snow showers Saturday afternoon/evening * Mainly dry Sunday through Wednesday with warming temperatures * Gusty WSW winds Sunday and Monday, with gusts of 20-30mph Saturday A weak low exits out of the Ohio River Valley late Friday into early Saturday then Passes well off shore to the south Saturday afternoon. Guidance continues to trend this low further south resulting in the majority of the QPF being off shore. It will be cold enough for any precipitation that falls Saturday to fall as snow, however snow accumulations at this time look unlikely with dry air near the surface and weak forcing aloft. Highs Saturday top in the mid to upper 30s. Sunday and Monday Drier with more sun on Sunday as a weak mid level ridge passes to the north. Another weak clipper system passes to the north late Sunday into early Monday, but the lack of moisture and forcing in southern New England will keep any snow it produces to the north. This clipper system will bring another prolonged period of gusty winds due to a strong pressure gradient. Winds begin to ramp up Sunday morning gusting out of the WSW at 20-30mph and remain elevated through Monday afternoon. BUFKIT soundings show mixing is possible up to 700mb, but winds aloft are only 35-45mph, thus limiting gust potential below the wind advisory threshold of 46mph. This is highlighted well with the NBM probs for gusts greater then 46mph at 0-10% region wide. Highs Sunday remain in the mid to upper 30s, but temps begin to warm Monday with highs in upper 30s to low 40s. Tuesday & Wednesday A 1030mb high pressure builds in and parks itself over the region by Tuesday afternoon leading to a stretch of dry and sunny conditions to start the week. High temps both days could over achieve guidance with WSW winds and mainly sunny skies. Used a blend of MOS and bias corrected guidance from the GFS and EURO to bump temperatures up. This brings highs into low to mid 40s both days. Winds both days will be light at 5-10mph with a weak pressure gradient due to the high overhead. Thursday and beyond Forecast confidence breaks down significantly as model guidance hints on a short wave approaching the region Thursday then possibly again Friday or Saturday. There is still significant timing and amplitude differences between the model sources at this time. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... Forecast Confidence Levels: Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 00z TAF Update: Tonight into Friday...Moderate confidence. VFR lowering to IFR/LIFR from 01-05z from west to east in light to moderate snow. Accums 1-3 inches possible north of the MA Pike. By 06-08Z snow exits east. VFR thereafter. Strong NW winds develop 06-09z with gust 35-45 kt through Fri morning, possible 50 kt gusts over the interior high terrain. Winds slowly diminishing in the afternoon. KBOS TAF...High confidence in TAF. VFR deteriorating to IFR after 02z tonight as snow develops. Heaviest snow should fall between 03-05z with only snow showers until 06z followed by improving conditions to VFR. Diminishing winds today becoming southerly late today. KBDL TAF...High confidence in TAF. VFR deteriorating to IFR after 00z tonight as snow develops. Snow ending by 05z followed by improving conditions to VFR. Outlook /Saturday Night through Monday/... Saturday: VFR. Breezy. Chance SN. Saturday Night: VFR. Breezy. Slight chance SN. Sunday: VFR. Windy with gusts up to 30 kt. Sunday Night through Washingtons Birthday: VFR. Windy with gusts up to 35 kt. Monday Night through Tuesday: VFR. Breezy. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. This evening through Friday night...High confidence. Light winds today as high pres moves across the waters, then another round of NW gales late tonight into Friday behind the departing low pres. Gusts 40-50 kt peaking late tonight into Friday morning with a low risk for storm force gusts over south coastal waters. Seas increase to 6-12 ft Friday morning. Winds gradually diminish Fri afternoon and become light Friday night with seas becoming 3-6 ft. Outlook /Saturday Night through Monday/... Saturday: Winds less than 25 kt. Chance of snow. Areas of visibility 1 to 3 nm. Saturday Night: Low risk for Small Craft Advisory winds with local gusts up to 30 kt. Areas of seas approaching 5 ft. Chance of snow, slight chance of freezing rain. Sunday: Strong winds with gusts up to 40 kt. Local rough seas. Sunday Night: Strong winds with gusts up to 40 kt. Areas of rough seas. Washingtons Birthday: Low risk for gale force winds with gusts up to 35 kt. Local rough seas. Monday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Tuesday: Winds less than 25 kt. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Wind Advisory from 1 AM to 1 PM EST Friday for CTZ002. Wind Advisory from 4 AM to 1 PM EST Friday for CTZ003-004. MA...Wind Advisory from 1 AM to 1 PM EST Friday for MAZ002-008-009. Wind Advisory from 4 AM to 1 PM EST Friday for MAZ003>006- 010>012-022>024-026. RI...Wind Advisory from 4 AM to 1 PM EST Friday for RIZ008. MARINE...Gale Warning from 4 AM to 1 PM EST Friday for ANZ230-231-236- 250-251-254. Gale Warning from 1 AM to 1 PM EST Friday for ANZ232>235-237. Gale Warning from 1 AM to 4 PM EST Friday for ANZ255-256. && $$ SYNOPSIS...BW/KP NEAR TERM...KJC/BW SHORT TERM...BW LONG TERM...KP AVIATION...BW/KP MARINE...BW/KP
Area Forecast Discussion
National Weather Service Memphis TN
917 PM CST Thu Feb 15 2024 ...New UPDATE... .UPDATE... Issued at 917 PM CST Thu Feb 15 2024 A weak cold front has pushed south to about a Jonesboro, AR to Huntingdon, TN line this evening. The front will continue to sag south eventually stalling near the TN/MS state line. Clouds will be on the increase tonight as warm air advection increases ahead of a surface low that will track into the Red River Valley by 12z Friday. A few showers will develop in the morning in the warm air advection regime but showers will become more numerous during the afternoon as the surface low pushes into the area and lift increases. Scattered thunderstorms are also possible as a reservoir of instability develops along and south of the stalled front. The latest HRRR indicates SBCAPES around 1000 J/kg and 0-6km shear values around 60 kts by mid afternoon which point to perhaps a low end severe (wind/hail) threat developing along and south of I-40 Friday afternoon into the evening. The CSU machine learning site has picked up on this and we will continue to monitor. && .SYNOPSIS... Issued at 313 PM CST Thu Feb 15 2024 A cold front will move into the Mid-South tonight and then stall out across the region Friday morning. With little moisture available at this time, no rain is expected tonight. As low pressure moves along the front on Friday, rain and a few thunderstorms are expected to move through the region. The cold front will move out of the region Friday night bringing much colder air for Saturday. Temperatures will moderate on Sunday and return back to above normal levels for Tuesday and Wednesday. && .DISCUSSION... (This evening through next Wednesday) Issued at 313 PM CST Thu Feb 15 2024 Skies are sunny across the Mid-South this afternoon with temperatures in the mid to upper 60s. A cold front extends from southwest Indiana through north central Arkansas and into extreme north Texas. This cold front will move into the Mid-South tonight and then stall out just south of I-40 by Friday morning. With little moisture in place, no rain is expected this evening. Temperatures will remain above normal tonight with lows Friday morning in the 40s to around 50 degrees. With the front remaining over the region on Friday, low pressure will develop along the front over southwest Oklahoma and track east into the Mid-South in the afternoon. Moisture will be on the increase so as the low approaches the region, rain showers and a few thunderstorms will across the Mid-South on Friday. Along with the rain, winds will increase as the low moves into the region. Winds speeds could approached Wind Advisory criteria over portions of northeast Arkansas and the Missouri bootheel for late Friday afternoon and into the early evening hours. Temperatures will remain warm ahead of the front with highs ranging from the mid 50s behind the front to around 70 degrees. As the cold front exits the region Friday night, precipitation will be ending from north to south. There is a possibility of some wintry precipitation over extreme northern sections of the Mid- South Friday evening, but the chance of it is quite small. Temperatures will be turn colder Friday night with lows Saturday morning in the mid 20s to mid 30s. High pressure will build into the central Plains on Saturday bringing dry and cold weather to the Mid-South. The surface high will drop south into south Texas on Sunday. Winds will shift to the southwest bringing milder air into the region which will moderate temperatures. With high pressure moving east of the region by Monday, a gradual warming trend will start with temperatures returning back to normal for Tuesday and Wednesday. && .AVIATION... (00Z TAFS) Issued at 612 PM CST Thu Feb 15 2024 VFR conditions are expected to prevail through the rest of the overnight period into early tomorrow morning. As a cold front approaches the airspace from the northwest, ceilings will begin to deteriorate starting at JBR mid morning. Probabilities of IFR ceilings are highest in northeast AR tomorrow; there looks to be a fairly tight gradient of IFR to MVFR ceilings between JBR and MEM. CAMs indicate a few scattered showers starting mid morning, picking up in coverage and intensity to prevailing -SHRA during FROPA after 18Z. Forecast soundings support enough of a thunder potential to warrant a PROB30 for a few hours of -TSRA at MEM late afternoon to early evening. Winds will start out mostly from the southeast overnight around 5 kts, picking up to 8-10 kts by mid morning as the pressure gradient tightens. Post-FROPA, the pressure gradient will tighten more, further increasing north winds to 12-15 kts sustained with 20-25 kt gusts behind the front through the end of the period. CAD && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...Flood Watch through Friday afternoon for MSZ001-007-008-011-012- 020. TN...None. && $$ PUBLIC FORECAST...SJM AVIATION...CAD
Area Forecast Discussion
National Weather Service Marquette MI
635 PM EST Thu Feb 15 2024 .KEY MESSAGES... -A Winter Weather Advisory for lake effect snow will be in effect for the western and northeastern portions of the UP tonight through Sunday. -Northwesterly wind lake effect snow belts are ongoing, causing locally moderate to heavy snowfall and periods of reduced visibility. -Nearly continuous lake effect snow chances continue through Sunday, mainly for NW wind snow belts. LES will be periodically enhanced by passing disturbances that also shift wind direction. -Another multi-day stretch of much above-normal temperatures increasingly likely for Monday-Wednesday next week. -Brief dry period early in the week will be followed by another round of wintry precipitation mid week onward. && .SHORT TERM /THROUGH TONIGHT/... Issued at 359 PM EST Thu Feb 15 2024 Radar imagery and GOES-16 Day Cloud Phase imagery show that synoptic snowfall has departed the UP and scattered lake effect showers have built in for the afternoon. RAP analysis shows a subtle shortwave passing over the UP this afternoon embedded in a 500mb trough over far northeast Ontario. Downstream of this trough, a particularly strong zone of showers had previously moved through the Keweenaw Peninsula around 16Z, reducing visibility at KCMX to 1/4SM for a period of time. That zone is over the Baraga/Marquette/Iron County area as of 19Z and will continue a trek southeast through the evening. Eventually, CAMs show a more consistent banding structure of NW LES snow showers continuing through the rest of the day and overnight. HREF probabilities of 0.25 inches of QPF are maximized around 20-60% in the terrain of the west half and in bands from Au Train/Chatham and east. SLRs should be high, near 20:1, as the inversion heights are near 10 kft and the DGZ is nearly entirely saturated and 3+kft deep. This brings some areas of the UP quite close to Winter Weather Advisory criteria, though the coverage of areas exceeding the criteria is scattered and incongruous and is leaving the forecaster enervated by low confidence. Given the satellite signature of bands forming over Lake Superior and the traversal of this zone of heavier precipitation, will start a Winter Weather Advisory for much of the eastern UP starting at 00Z. For the west, will start a WWA slightly later to allow for more time for the bands of precipitation to build, given the shorter NW fetch of Lake Superior in the west relative to the east. Additionally, gusty winds up to 40 mph along the lakeshores is creating an isolated blowing snow risk, adding to the reductions in visibility caused by the falling snow. && .LONG TERM /FRIDAY THROUGH THURSDAY/... Issued at 351 PM EST Thu Feb 15 2024 A multi-day lake effect snow regime continues at least through Sunday, mainly for the northwest wind snow belts. While LES largely wraps up Sunday night, some lighter LES may continue through Monday across the eastern UP. Ensembles continue trending toward a stretch of much above-normal temperatures for early next week, especially across the western UP. Record highs/lows for Feb 19-21 range from 44- 56 and 32-40, respectively at WFO MQT so a few more broken records are possible. A cold front around Thursday brings more seasonable temperatures and lake effect snow chances late next week. Starting with tonight, northwesterly LES will be ongoing at 12z Fri with only minor changes in prevailing wind direction expected through Saturday morning. However, an upper level trough moves through during this time-frame, further dropping 850mb temperatures to near -20C by Friday evening. Several CAMs still advertise potential for a surface trough or mesolow focusing a brief period of heavier LES sometime during the day Friday. Simulated reflectivity also indicates the potential for a dominant band extending from the tip of the Keweenaw into eastern Alger, northern Schoolcraft, and possibly Luce counties. HREF ensemble guidance shows snowfall rates generally around a tenth to quarter inch across the NW wind belts throughout the western and eastern UP, locally higher in heavier banding. However, it also highlights a potential (around 20-40%) for higher snowfall rates around 1in/hr at times Friday through Friday night. Now, as for snow totals. Inversion heights increase to as high as 6- 7kft by Friday afternoon, with steep lower level lapse rates and saturation all the way down to the surface. So, SLRs should be rather high. Guidance keeps them generally around 20:1. With periods of heavy QPF, we should be left with several inches of snow by Saturday morning. The highest amounts would be where we can see some localized terrain enhancement. For that reason, a Winter Weather Advisory will go into effect for portions of the western and eastern UP beginning tonight and continuing through Friday night. A energetic clipper system approaches the area on Saturday, with winds backing westerly Saturday morning to perhaps southwesterly Saturday afternoon/evening ahead of the cold front. This results in lingering LES lifting northward. However, 850mb temps stay cold enough for LES as the winds back more southwesterly, suggesting potential for a more dominant LES band streaming across the Keweenaw (e.g. Bayfield Bomber). Several deterministic models bring a wave of WAA-induced snow southeast across the UP Sat aftn/eve, but amounts appear light if it occurs. The clipper system`s cold front moves through Saturday night with northwesterly LES returning by Sunday morning. Depending on the track of the clipper system there could be a period of lake enhancement before returning to pure LES for NW wind snow belts by Sunday evening. The ensemble consensus is for a sub-1000 mb surface low tracking southeast across Ontario, just east of Lake Superior suggesting the best potential for lake enhancement is in Ontario. The duration of post-clipper LES also depends on storm track with a farther west track allowing the arctic air mass to become more entrenched across the area as compared to a farther east storm track. Due to diminishing forecaster confidence, this forecast package ends high-end LES PoPs during the day on Sunday. Looking ahead into next week, operational and ensemble model guidance has trended toward a considerable warm-up early next week with highs generally ranging in the 30s all week. The warmest days will be Tuesday and Wednesday; the Grand Ensemble has probabilities increasing to 20-30% for high temperatures of at least 40F in the western UP. Large diurnal swings are expected with temperatures likely falling into the teens and 20s all week. Another low pressure system moving out of the Plains will touch off our next round of snow and mixed precipitation midweek. Associated cold front passage on Thursday should usher in the next more seasonable airmass, with 850mb temperatures falling below -10C and keeping in chances for lake effect through the end of the week. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 635 PM EST Thu Feb 15 2024 Periodic lake effect snow showers will result in variable flying conditions across space and time throughout the 00Z TAF period. Overnight, expect VFR vsby to prevail at IWD/SAW, although brief MVFR reductions in snow showers cannot be ruled out. Cigs should be borderline VFR/MVFR. MVFR cigs/vsby are expected to prevail at CMX, although brief IFR vsbys are possible especially at the start of the TAF period. Snow showers are expected to be most frequent at CMX during the daylight hours tomorrow, where IFR vsby is expected to prevail. At IWD/SAW, MVFR cigs/vsby are expected to prevail, with periodic IFR vsbys possible in heavier snow showers, especially in the afternoon at SAW. && .MARINE... Issued at 351 PM EST Thu Feb 15 2024 NW gales to 35 to 40 knots continue this afternoon behind a cold front, but will slowly decrease overnight. In addition to gales, we will continue to see moderate to locally heavy freezing spray return across the lake tonight through Friday morning. Northwest winds decrease to around 20-25 kts for Friday with another cold front potentially increasing NW winds to around 25-30 kts Friday night. A low pressure tracking near Lake Superior brings renewed gale potential this weekend with winds backing southwesterly ahead of the cold front Saturday then quickly veering northwesterly behind it overnight. WSW gale probabilities are about 30% in the west half of the lake Saturday. Gale probabilities increase above 50% and shift northwesterly behind the cold front Saturday night with strong cold air advection likely to trigger another round of period of gales on Sunday, mainly across the eastern lake. NW winds quickly decrease overnight into Monday morning, falling below 20 knots by the afternoon. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory from 1 AM EST /midnight CST/ Friday to 7 AM EST /6 AM CST/ Saturday for MIZ001>004-009-084. Winter Weather Advisory until 7 AM EST Saturday for MIZ006-007- 085. Lake Superior... Small Craft Advisory until 1 AM EST Friday for LSZ246-247. Small Craft Advisory until 1 PM EST /noon CST/ Saturday for LSZ240>244. Small Craft Advisory until 1 AM EST Saturday for LSZ245. Small Craft Advisory until 10 AM EST Friday for LSZ248. Small Craft Advisory from 4 PM Friday to 1 AM EST Saturday for LSZ248. Gale Warning until 1 AM EST Friday for LSZ249>251-266-267. Small Craft Advisory from 1 AM Friday to 1 PM EST Saturday for LSZ249>251. Lake Michigan... Small Craft Advisory until 1 AM EST Friday for LMZ221-248-250. && $$ SHORT TERM...GS LONG TERM...LC AVIATION...Thompson MARINE...LC
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
737 PM MST Thu Feb 15 2024 .UPDATE... Issued at 734 PM MST Thu Feb 15 2024 Snow is decreasing from northwest to southeast, so have trimmed the advisory. Light snow and light winds continue over the rest of the advisory area. Hi-res models show snow exiting south central SD by 06Z, so will continue to monitor the snow trends and determine possible additional cancellations. && .KEY MESSAGES... 116 PM MST Thu Feb 15 2024 - Snow continues through the evening. Total even snow accumulation of 2-6" expected from NE WY, the Black Hills, and into south- central SD. - Lingering light snow across SW SD and the Black Hills Friday; minor accumulations expected. - Warmer and dry this weekend into early next week. && .DISCUSSION...(This Evening Through Thursday) Issued at 116 PM MST Thu Feb 15 2024 Upper level analysis shows upper low slowly lifting through northern Ontario with a trailing and elongated upper trough axis from Manitoba westward into Alberta. Water vapor imagery shows compact upper shortwave trough pivoting through the Northern Plains this afternoon. A developing area of low pressure is centered across SE WY and NE CO with southeasterly to northeasterly winds across the forecast area. A mid-level baroclinic zone stretches from NE WY through the forecast area into south-central SD. Snow continues across the forecast area this afternoon as large- scale ascent overspreads the area. Recent model trends have shunted the potential for snow further south with a tighter northern gradient than previous forecasts, which has been incorporated into the forecast amounts. Still expect widespread 2-6" of total snow across much of western SD, far NE WY, and south-central SD by Friday morning. Locally higher amounts are possible across the northern Black Hills and foothills (upslope enhancement) and south-central SD where more efficient snowfall production is possible (greater DGZ depth + lift within DGZ). Higher res CAMs (although recent HRRR runs are struggling mightily handling snow that is occurring now, which has reduced overall QPF...) and the 12z HREF suite highlight a widespread area of 0.2-0.4" of total QPF through Friday morning from the Black Hills into south-central SD. While a few isolated spots of warning criteria snows are possible (mainly across south-central SD), will continue with the Winter Weather Advisory. Snow will taper off from west to east later this evening into the overnight hours. The upper trough axis draped across southern Canada will drop southward Friday with an additional round of light snow across NE WY and SW SD through the day Friday. An inch or so of additional accumulation is possible Friday morning into the afternoon. Upper level ridging builds across the western half of the US by Saturday. Expect slowly warming temperatures this weekend, although snow cover will limit maximum temperature potential Saturday and Sunday. Overall, temperatures will trend warmer than normal through next week with generally dry weather expected. && .AVIATION...(For the 00Z TAFS Through 00Z Friday Evening) Issued At 416 PM MST Thu Feb 15 2024 Widespread MVFR/IFR ceilings will continue through most of the period, improving from north to south Friday afternoon. Snow will continue to produce MVFR/IFR/local LIFR visibility into the evening and overnight. The snow will decrease in intensity from west to east tonight, but then another round of light snow is expected to quickly follow tonight into Friday morning. Visibility will improve Friday morning as the snow finally exits the area. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...Winter Weather Advisory until 11 PM MST this evening for SDZ024>031-042-072>076. Winter Weather Advisory until 2 AM MST /3 AM CST/ Friday for SDZ032-043-044-046-047-049-077. WY...None. && $$ Update...Pojorlie DISCUSSION/KEY MESSAGES...SE AVIATION...Pojorlie