Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/20/23

Area Forecast Discussion
National Weather Service Indianapolis IN
1009 PM EDT Sun Mar 19 2023 .Forecast Update... Issued at 1009 PM EDT Sun Mar 19 2023 Little changes made to the short term forecast this evening as everything seems to be going on track. Current surface analysis shows an area of high pressure centered over the Gulf Coast states with weak southwest flow across Central Indiana. Satellite imagery shows clear skies across the entire Ohio Valley this evening, which will lead to optimal conditions for radiational cooling through the night. All locations have dropped below freezing as of 10 PM and will continue to plummet into low 20s by Monday morning. Minor tweaks made to the forecast for tomorrow. Southwest flow pattern persists with high pressure south of the region. Short term guidance indicates deep mixing up to 4 kft agl by tomorrow afternoon. RAP forecast soundings show mixing into a dry layer located just above the surface, which will likely result in dew point and RH values well below NBM guidance during peak heating of the day tomorrow. This change brings min RH values tomorrow afternoon into the mid 20s to mid 30s across the entire region. These patterns also produce highs a few degrees above guidance, so nudged high temps up to the low 50s for much of the region. Deep mixing will also lead to stronger winds aloft mixing down to the surface. Highest wind gusts looks to be across the northwest half of the forecast area, closer to the stronger low level jet. Expect wind gusts around 20-30 mph Monday afternoon, with the highest gusts closer to the Lafayette area. These dry and breezy conditions may pose a slight fire weather threat during the afternoon hours tomorrow; however the risk is not high enough to warrant the issuance of any products or alerts at the moment. && .Short Term...(This evening through Monday) Issued at 251 PM EDT Sun Mar 19 2023 Quiet and warmer weather continued across central Indiana this afternoon. The March sun was melting away what snow cover there was across the forecast area. Cumulus across the southern forecast area were gradually diminishing as warmer air aloft moves in. Cumulus will continue to gradually dissipate for the remainder of the afternoon. Temperatures will still be below normal but warmer than Saturday`s readings. Tonight, quiet weather will continue as surface high pressure (centered south of the area) remains in control. This will keep winds from going calm and place some limit on radiational cooling. However, it will still be cold for two-thirds of the way through March. Blended guidance still looks a bit warm, so will cut some. Lows will be around 20 into the lower 20s. On Monday, southwest winds will bring in warmer air. High pressure will still be in control, but a cold front will be relatively not that far to the northwest of the area. As a weak upper wave interacts with this, some mid and high cloud will pass through, especially north. Winds will increase aloft with this setup, and some momentum transfer will occur to the surface. Winds will gust into the 25 to 30 mph range. Highs will be in the upper 40s to around 50 thanks to the warm advection. && .Long Term...(Monday night through Sunday) Issued at 251 PM EDT Sun Mar 19 2023 * Moderation Through Thursday...Then Near-Normal Temperatures * Potential for Heavy Rain/Flooding Within Thursday-Friday Timeframe Monday Night and Tuesday... A zonal ridge will oversee the return flow, yet still-dry, side of the current dome of Canadian high it drifts eastward across roughly the eastern half of the CONUS. Scattered clouds are expected over the northern tier Monday evening as the region catches the southern edge of a weak wave crossing the Great Lakes. Bigger story will be a 998 mb surface low over western Kansas Tuesday, and the corresponding gradient and south-southwesterly flow off of the western Gulf of Mexico...that will begin to re-moisten the column. High/mid clouds will thicken top-down from southwest to northeast from pre-dawn to midday Tuesday...with stratus expected to arrive during the afternoon. Mainly southernly winds will gust as high as 20-25 mph for much of these two periods, with organized rain possibly reaching western counties by early Tuesday evening. Temperatures will continue their moderating trend, with lows around 30F and another seasonably mild day Tuesday with readings peaking in the mid-50s for most locations. Tuesday Night through Friday... A generally unsettled pattern will prevail through the rest of the workweek as several waves pass near/over central Indiana. Guidance is continuing to show roughly three phases of rain potential. First is a rather light rainfall over Tuesday night-Wednesday courtesy of a weakly-forced, yet rather broad ribbon of Gulf moisture...with as much as 0.25-0.50 inches of rain across southern the region basks in the mild warm sector breezes of the storm system passing well to our northwest. Next would be an overall lull in organized rain as the nearly- stationary frontal zone between the departing system and next low pressure over Kansas drags into the northwestern Midwest around the late Wednesday/early Thursday timeframe. Gusty southerly winds will serve to steadily recharge precipitable water values across our CWA in mainly the 1.00-1.50 a rather narrow axis of greatest deep moisture likely extends from the Ozark Plateau eastward into the Midwest - near/north of the I-70 corridor. Lack of forcing should translate to overcast conditions with occasion light rain/ drizzle. Although a few ensembles suggest the potential for moderate rainfall, especially towards our northwest zones which should be closer to the slowly approaching boundary. The long term`s greatest concern then comes through the late work week when adequate forcing should arrive...between the slowly- crossing front as well as embedded mid-level produce moderate-heavy rainfall over at least parts of the region. Additional rainfall would potentially include greatest 12-hour totals of 1.00-3.50 inches...with the heavy rainfall threat transitioning from northern to southern counties through the late week along with the boundary`s passage. Concerns for river and areal flooding would be valid should this potential be realized, although guidance so far is suggesting any late-week rains over 2.50 inches should not be widespread. At least isolated thunder cannot be ruled out amid these heavier rains, with much of the region progged to fall on the warm side of the boundary through at least late Thursday, with dewpoints expected to approach 60F over southern portions of Indiana. Temperatures should trend from above normal to near normal through Friday. Saturday through Sunday... The upcoming weekend should feature perhaps 2-3 periods of mainly dry weather with rather weak high pressure expected to slide across the Great Lakes as the departing system tracks through the Northeast. The next storm system, probably back to a track to our northwest...will bring chances of warm frontal and/or warm sector rain by the end of the long south-southwesterly flow returns ample deep moisture. Indianapolis` normal max/min through the long term is 55/36. && .Aviation...(00Z TAF Issuance) Issued at 727 PM EDT Sun Mar 19 2023 Impacts: * VFR conditions expected through the next day Discussion: High pressure centered south of the region will keep conditions dry and calm over the next day across Central Indiana. Subsidence under the high tonight will result in mainly clear skies across the entire region. Winds will diminish after sunset as low level mixing shuts off and the pressure gradient remains weak. High pressure shifts eastward tomorrow with southerly return flow increasing through the region. Southwesterly Low level jet increases to around 25 kts Monday afternoon. Expect steep lapse rates within the boundary layer and mixing up into the low level jet to result in gusty winds up to 20 to 25 mph late Monday morning through Monday evening. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...CM Short Term...50 Long Term...AGM Aviation...CM
Area Forecast Discussion
National Weather Service Marquette MI
742 PM EDT Sun Mar 19 2023 .SHORT TERM...(Through Tonight) Issued at 318 PM EDT SUN MAR 19 2023 Water vapor imagery and RAP analysis show that the deep mid-level low that brought the wind and LES to the area yesterday is now in southern Quebec. A shortwave noted dropping se across Manitoba and northern Ontario is the next feature of interest for the short term. Ahead of this feature, a dry waa regime is occurring across the Upper Great Lakes today. Sharper 850mb temp gradient running vcnty of the eastern shoreline of Lake Superior combined with some moisture off of the lake has supported some -shsn/flurries across the lake in Ontario. Otherwise, the dry air mass has allowed for abundant sunshine across the fcst area today, and temps have risen into the 30s as of 19z. A few locations are around 40F. Relatively tight pres gradient btwn high pres centered over se OK and a cold front in northern Ontario associated with the aforementioned shortwave is resulting in a breezy day, especially on the Keweenaw. Winds at KCMX have been gusting to around 40mph for much of the day. Cold front in northern Ontario will sweep s into Upper MI tonight. Observations upstream vcnty of the cold front reveal stratocu and some -shsn. As the cold front drops across Upper MI late evening thru early Mon morning, convergence along the front combined with 850mb temps around -10C over Lake Superior should further aid the sct -shsn/flurries that are currently occurring vcnty of the front. Nothing more than schc/chc mention seems appropriate given that the shortwave passes by to the n of the area. By 12z Mon, 850mb temps will be down to around -14C across northern Lake Superior, and a marginal for LES -12C across the southern part. Result may be some additional post frontal flurries/-shsn under developing northerly low-level flow. Expect min temps tonight in the mid teens to mid 20s F. .LONG TERM...(Monday through Sunday) Issued at 338 PM EDT SUN MAR 19 2023 Ensemble means are overall indicating near normal temps for the extended fcst period, although a couple of ensembles (i.e. the GEFS and GEPS) are expecting some above normal temps near the end of the fcst period. Moving into Monday, expect light LES showers to continue over the N/NE snow belts, particularly over the central and west as the weak cold front continues towards Lower MI. With low level clouds continuing throughout the day, mid level clouds moving in overhead, light snow showers/flurries occurring across the area, and very weak CAA from the north, I dropped highs down a bit from the previous fcst, thinking that most of the area will stay below freezing tomorrow save for the south central. That being said, with the higher sun angle, I wouldn`t be surprised if we saw a little bit of snow melt across most of the area. As we head into the overnight hours, expect some light snow showers to move over the interior west near WI and the south central early, with possibly some light LES/flurries occurring over the NE snow belts save for areas west of the Keweenaw as light winds veer with time. There may be some breaks in the cloud cover over the UP Monday night as the mid level cloud cover leaves and the low level lake-effect clouds erode across the area. While I decreased temps a bit from the previous NBM fcst, should enough cloud cover erode away we may see lows bottom out to the negative single digits in the interior west and single positive digits in the interior central and east (the NBM10th percentile highlights this quite well). As we move into Tuesday, a low pressure system over the Central Plains begins to lift towards MN. As it does so, guidance suggests that an area of weak isentropic lift moves through the UP late Tuesday afternoon ahead of the warm front of the low. While only a dusting to a few tenths of an inch of snowfall is really all that`s expected, a band of some light to locally moderate snowfall could be seen along this band, which could cause some minor visibility concerns if driving. Once the band lifts out of the area, expect a quick break in the precip before the main warm front moves into the area late. Compared to yesterday`s fcst, its seems that the timing of the low has slowed ever so slightly, allowing for colder air to arrive quicker over the UP. However, not really expecting snow totals to increase as overall QPF from this system seems to have decreased a little since yesterday. Overall, still expecting anywhere from a dusting to a wet inch in the south central, 2 to 4 inches of wet snowfall in the Keweenaw, and 1 to 2 inches everywhere else in the UP. Most guidance has a majority of the area (save for maybe the Keweenaw) transitioning over to rain for a few hours before the front completely passes through the area. However, I do have some doubts with that as model guidance is showing nearly unstable lapse rates near the sfc once the warm front passes through, and given the cloud cover remaining over the area and the mostly saturated profile (save for in the lowest levels), I have some suspicion that those lapse rates aren`t going to be achieved. Therefore, I lowered temps Wednesday with the NAM12km, as I think it nudges the fcst in the right direction and keeps highs mainly in the upper 30s (although some spots like in the south central and the south wind downslope areas could get up to the low 40s). Thus, I think that some spots in the north central, west, and Keweenaw may stay snow for the whole event, although I do think temps will be warm enough to bring at least some level of snow melt across the entire area during the day Wednesday. The cold sector of the low is set to move into Upper MI Wednesday evening; some rain and snow showers could be seen ahead and along the cold front. Once we move into Wednesday evening, there is quite a bit of model spread as to what will happen. One set of solutions has precip developing along a shortwave low moving through the Ohio Valley, whereas another solution could be a strong wrap-around low that lifts through Lower or Upper MI. Should the former solution be true, then we will likely stay mostly precip free; should the latter be true, we could see some additional snowfall, most likely over our south central and east. Models do reconverge and have high pressure settling over us Thursday night through Friday, which could bring nice sunny skies over us, probably creating some more snow melt across the area. Moving into this weekend, medium range guidance suggests that a strong low pressure will develop over the SE US or Southern Plains and lift northeast towards the Great Lakes. Should low trend more westward, like in the 12z Euro, we may see some wet snowfall, especially over our south central and east. Past the end of this fcst period, ensemble means hint at temps averaging below average, meaning we could see a chillier end to March and start to April. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 739 PM EDT SUN MAR 19 2023 Ahead of a cold front currently dropping s thru northern Ontario, very dry air will remain over the area along with gusty w to sw winds. As a result, VFR conditions will prevail at IWD/CMX/SAW into the evening hrs. Winds will gust 20-30kt, strongest at CMX. Winds will probably decouple at SAW this evening, leading to a period of LLWS. As the cold front passes across the area tonight, MVFR cigs will set in and winds will diminish, beginning first at CMX around 04z. There may be -shsn/flurries with fropa at any of the terminals, but don`t expect vis to drop any lwr than MVFR if -shsn occur. MVFR cigs will then prevail at all terminals thru Monday. A few flurries will be possible at times. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 355 PM EDT SUN MAR 19 2023 W to WSW`rly winds of 20 to 30 knots, with a few gale force gusts up to 35 knots over the western lake near the Keweenaw and Porkies early this evening diminish to generally 20 knots or less behind a cold front dropping down from northern Ontario tonight. Expect the light winds to continue across the lake until Tuesday, when a low pressure lifting from the Central Plains towards the western lake brings E`rly winds of 20 to 30 knots across the western lake, with a few gale force gusts up to 35 knots being possible near the MN shoreline. As the low approaches the western lake Tuesday night, expect the winds to slowly veer with time, weakening over the western lake while increasing to SE`lry winds of 20 to 30 knots across the eastern half late; some gale-force gusts up to 35 knots may be possible Wednesday morning, but I have my doubts due to the WAA regime. Once the low gets through the lake by Wednesday night, expect the cold air behind it to bring NW`rly winds of at least 20 to 25 knots across the area Wednesday night into Thursday. Afterwards, expect winds to remain light at 20 knots or less as high pressure builds in Thursday night into Friday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Gale Warning until 8 PM EDT /7 PM CDT/ this evening for LSZ162- 242>244-263-264. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...TAP AVIATION...Voss MARINE...TAP
Area Forecast Discussion
National Weather Service Pittsburgh PA
649 PM EDT Sun Mar 19 2023 .SYNOPSIS... High pressure across the Upper Ohio Valley and Allegheny Mountains will result in cool, dry weather to start the work week. A low pressure system moving across the Great Lakes on Wednesday will bring the next chance of rain to the area. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 645 PM Update: Latest radar and satellite imagery shows that shower activity has diminished as high pressure builds across the forecast area and drier air has worked into the low/mid- levels. Breezy conditions remain, but should subside soon after sunset between the pressure gradient relaxing and PBL decoupling. Otherwise, forecast remains on track. Previous... Recent mosaic radar imagery suggests ongoing lake enhanced snow showers in conjunction with a crossing thermal trough, evident via 700mb RAP analysis. Building sfc high pressure and departing shortwave ascent should eventually diminish precipitation chances north of I-80 through this afternoon. That dry advection should also help dissolve the existing stratocu cloud layer across northern zones, with a lingering scattered cloud deck near 5,000ft expected through early eve. Wind transport from that level, roughly ~700mb, will maintain wind gusts near 15-20 mph today before decoupling returns light wind after sunset. Otherwise, below normal temperature will continue today, with highs in the upper 20s to 30s, ~10 to 15 degrees below average. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... Guidance continues to signal a return to a quasi-zonal flow on Monday and temperature should slowly moderate back toward climatological norms. Surface high pressure will support dry and mostly sunny conditions, with southwesterly wind gusting 10-15 mph. Tuesday will feature similar conditions, though a digging western CONUS closed low should promote subtle height rises across the eastern CONUS and increase high temperature by a few, additional degrees. For context, the average high/low temperature this time of the year for PIT is 50F/30F. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Rain will likely return Wednesday as a Colorado low ejects northeast into the Midwest and moisture within the Gulf of Mexico drives north. Drier air, from the lingering ridge, and weak ascension should limit precipitation amounts to less than a quarter of an inch across the region. The potential for heavier precipitation, based on current model trends, will likely occur Friday into Saturday as a new low pressure system develops in the Great Plains and engages with a stationary boundary positioned from the Mississippi River Valley into the Ohio River Valley. A swath of heavy rain could start just west of the Ohio River Valley and migrate south into the southern Appalachians as the ridge axis over the East Coast weakens. The NBM currently projects 40-50% probabilities of QPF exceeding 0.50 inches in 24 hours during this time period; 15-30% for over 1.0 inch. The Weather Prediction Center has issued a Marginal Outlook for Excessive Rainfall for Day 5 to highlight the potential of high water if convective showers remain somewhat-stationary and robust. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... VFR is expected through the TAF period as high pressure builds across the Ohio and Tennessee Valley region. W-SW wind gusts will diminish after sunset as mixing decreases, though speeds will remain near 10 kt through the period. .OUTLOOK... VFR is expected through Tuesday under high pressure. Restriction potential in occasional rain returns Wednesday through Friday as a series of low pressure systems track across the region. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...Brown NEAR TERM...05/Brown SHORT TERM...05 LONG TERM...05 AVIATION...WM
Route 62. As mentioned in the previous forecast discussion, unsure
how precipitation on Tuesday will impact wind speeds, so held off on
any other wind-related headlines, though some Wind Advisories may ultimately be needed across the Mojave Desert. Temperatures will range from 10 to 20 degrees below seasonal averages through the remainder of the forecast period. Otherwise, an active pattern persists. && .HYDROLOGY...Minor-to-moderate flooding from higher-than-normal streamflows are forecast to continue within the Meadow Valley Wash through the week due to recent rain, regional snowmelt, and controlled releases from the Eagle Valley Dam in preparation for next week`s storm system. Forecast precipitation across the southern Great Basin next week will only act to exacerbate the ongoing flooding in Lincoln County. && .AVIATION...For Harry Reid...Light southeast winds to pick up from 18z on with gusts 20-25kt through the afternoon. Occasional light showers and ceilings of 6-8kft can be expected through mid to late afternoon. Visibilities should generally remain VFR. Winds to decrease by 07z, remaining light overnight with improving ceilings and decreasing showers. For the rest of southern Nevada, northwest Arizona and southeast California...Breezy south winds will persist as another storm system affects the region. Winds will be strongest at KBIH, with gusts around 25-35kt. Elsewhere, gusts should be more in the 15-25kt range. Broken to overcast skies and sporadic showers will also accompany the storm system, though visibilities generally look to remain VFR and ceilings in the 6-8kft range. The one exception is KBIH, where ceilings will hover between 3-5kft through the afternoon. Winds to become light toward sunset with improving sky conditions and decreasing rain chances. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION...Varian HYDROLOGY...Pierce AVIATION...Austin For more forecast information...see us on our webpage: or follow us on Facebook and Twitter