Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/07/23

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
751 PM CST Fri Jan 6 2023 .UPDATE... Issued at 750 PM CST Fri Jan 6 2023 Added some counties to the current Dense Fog Advisory and extended it through mid morning Saturday based on latest area webcams, observations, and satellite trends. UPDATE Issued at 517 PM CST Fri Jan 6 2023 No major changes planned to the forecast this evening at the moment. Monitoring expansion of stratus/fog field and will determine any adjustments that may become necessary to the current dense fog advisory. && .SHORT TERM...(This Evening through Saturday Night) Issued at 146 PM CST Fri Jan 6 2023 The main forecast challenge continues to be fog. At 1 PM CST, some areas of the CWA have seen the fog and low clouds burn off, while other areas remain socked in. And, satellite imagery/webcams do not suggest the fog/low clouds are in any hurry to burn off/dissipate. Temperatures are in the upper single digits to upper teens. And, winds are light and variable. The latest HREF along with the RAP model and the NAM model in BUFKIT all support the potential for more fog/low stratus tonight. Several visibility guidance products also have visibility dropping to zero or near zero overnight. Opted for a blend of the RAP13TL and CONSshort for the visibility grids (for aviation and for creating fog grids for the forecast) for tonight through Saturday night. Depending on how things go for the rest of this afternoon, there may be some additional counties cleared from the Dense Fog Advisory. There has been some improvement across portions of north central and northeast South Dakota. Otherwise, if it`s still "very" foggy at 3 PM CST, the plan is to continue the Dense Fog Advisory until 9 PM CST this evening. At that point, the next shift should have a decent feel for if/where to re-introduce or extend in time a Dense Fog Advisory, or cancel altogether, for the overnight hours into Saturday morning. Everything else in the dry short term forecast period was NBM4.0 guidance, which includes a light south or southwest wind developing later tonight and persisting through Saturday night, and temperatures tonight and Saturday night generally in the single digits above zero and during the day on Saturday rebounding into the teens and 20s. .LONG TERM...(Sunday through Friday) Issued at 146 PM CST Fri Jan 6 2023 The long term portion of the forecast will feature mostly dry conditions with seasonal average temperatures. The period begins on Sunday with an trough of low pressure crossing the region, bringing a weak wind shift and warmer temperatures into the area. Temperatures at 925 mb could reach above the 75th percentile, leading to the possibility of warmer highs on Sunday. Slightly better mixing winds, with a west to northwesterly component would help overcome the deep snow pack across much of the CWA. Dry conditions with seasonal temperatures will continue through the first half of the work week, Monday through Wednesday. A deep upper level trough should slide across the central Conus Wednesday night through Thursday, with the main surface low passing well south and east of the CWA. While the GFS and Canadian support dry conditions during this time period, the ECMWF suggests light, accumulating snowfall, mainly associated with the upper level trough. The ECMWF also suggests a tight pressure gradient across the region, Thursday into Friday, which may promote patchy blowing snow. Since the storm system may occur on day 6 and 7, overall forecaster confidence is low. && .AVIATION...(For the 00Z TAFS through 00Z Saturday Evening) Issued at 517 PM CST Fri Jan 6 2023 Terminals KABR,KATY,KPIR,KMBG All sites except KPIR have fallen to IFR in fog and stratus already. The stratus is closing in on KPIR and will likely fill in within the next few hours. The IFR conditions will linger into and through Saturday morning. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...Dense Fog Advisory until 10 AM CST /9 AM MST/ Saturday for SDZ003>011-015>023-037. MN...None. && $$ UPDATE...Wise SHORT TERM...Dorn LONG TERM...SD AVIATION...Wise
Area Forecast Discussion
National Weather Service Quad Cities IA IL
535 PM CST Fri Jan 6 2023 ...00Z AVIATION UPDATE... .SYNOPSIS... Issued at 215 PM CST Fri Jan 6 2023 High pressure and dry air has kept things quiet across the region. We continue to see mostly cloudy skies, thanks to lingering cyclonic flow over the western Great Lakes, and a mid-level shortwave that has brought a mid-level stratus deck across the southern half of the region. Temperatures have remained cold over northeastern Iowa, with temperatures hovering in the upper teens, with areas over our far south where more sunshine was seen warmed up to the middle 30s, under generally light northwest winds. && .SHORT TERM...(This evening through Saturday night) Issued at 215 PM CST Fri Jan 6 2023 Key Messages... 1) Dry conditions expected for tonight through Saturday morning, with some patchy fog possible 2) Chances of light accumulating snow will increase Saturday afternoon, lasting through Sunday morning Dry conditions will continue tonight through Saturday morning, thanks to an area of surface high pressure and confluent flow aloft. Latest NAM and RAP model soundings are suggesting that a rather stout low-level thermal inversion, with lots of dry air overhead, will develop tonight, which should result in at least some patchy fog tonight. Some of the high-res guidance are even hinting at perhaps some locally dense fog in some places tonight, but the NBM v4.1 probability of visibility reductions of 3 miles or less are around 30 to 60 percent - highest over Cedar Rapids and points north. Still thinking some patchy fog tonight is likely, but uncertainty remains on how widespread/dense it will become. Eventually, fog will dissipate after sunrise Saturday. Attention then turns to increasing chances of light snow Saturday afternoon into the morning hours Sunday. This is developing ahead of a mid- level shortwave trough, where 850-700 mb layer warm air and moisture advection looks to increase. Light accumulating snow will continue through Sunday morning, especially across our southern areas. As the aforementioned mid- level shortwave makes its way across central Iowa, the attendant upper-level trough will amplify slightly, leading to a bit of a stronger cyclonic circulation. Global models are progging a few positive vorticity maxima that will churn around the shortwave, with the strongest forcing expected across the southern forecast area. However, with this forecast package, the model spectrum is indicating a trend to lower QPF, and thus, lower snowfall amounts, with the 25th and 75th quartiles indicating between 0.01" to 0.05" possible of total QPF. Translation: not a whole lot of moisture to work with. Ultimately, with low snow-to-liquid ratios, this results in only between 0.1" to 0.5" of new accumulations - heaviest over our far southern counties. .LONG TERM...(Sunday through Friday) Issued at 215 PM CST Fri Jan 6 2023 Key Messages... 1) Overall, relatively dry long term period with above normal temperatures in the 30s to mid 40s Sunday, some lingering light snow is possible during the morning hours across areas east of the MS River and mainly south of I-80 with a dusting of additional snow accumulations at best. Sunshine will return area wide by afternoon as high pressure builds into the area. Highs will be in the lower and middle 30s. Monday through Wednesday, dry conditions will prevail as high pressure dominates. A weak system will move across the area Monday into Tuesday, but moisture is lacking so only expect a slight increase in southerly flow and some warmer temperatures. Highs Monday, Wednesday and Thursday will be in the upper 30s to mid 40s, with Tuesday being a bit cooler behind the fropa with readings in the mid 30s to low 40s. Thursday into Friday, a low pressure system is forecast to move across MO and IL bringing rain and then a switch over to snow as it exits. There remains some timing and location differences, and therefore confidence remains low. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 530 PM CST Fri Jan 6 2023 Starting out the TAFs with VFR conditions. However, later tonight into Saturday morning anticipate radiational fog developing with MVFR to IFR visibilities and areas of LIFR/VLIFR. Some stratus and IFR/LIFR CIGs are also possible but confidence is lower on this. A system may begin to spread some light precipitation into BRL late in the period, but being in the last 6 hours and low confidence I`ve left out mention. && .HYDROLOGY... Issued at 1015 AM CST Fri Jan 6 2023 The River Flood Warning for Joslin on the Rock River has been cancelled. The river level is expected to slowly fall. The river level may fluctuate due to ice presence. The Flood Warning for an ice jam near River Road in East Moline, Illinois has been cancelled. While the ice jam is expected to continue, the impacts from the flooding are not expected to change in the near future. Please continue to heed remaining road closures. && .CLIMATE... Issued at 300 AM CST Fri Jan 6 2023 No changes were made to the 3 AM issuance. Week 2: The Climate Prediction Center has above normal temperatures favored across the Upper Mississippi Valley region for the third week of January (13th - 19th); above normal precipitation is slightly favored. This could mean several days with highs well above freezing, right during the coldest time of the year. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...Schultz SHORT TERM...Schultz LONG TERM...14 AVIATION...McClure HYDROLOGY...14 CLIMATE...Uttech
Area Forecast Discussion
National Weather Service Lincoln IL
741 PM CST Fri Jan 6 2023 .SYNOPSIS... Issued at 302 PM CST Fri Jan 6 2023 Quiet weather will prevail across central and southeast Illinois tonight and Saturday, before an area of low pressure brings light wintry precipitation Saturday night into Sunday morning. Snowfall amounts of less than 1 inch are anticipated along and north of I-72, with little to no snow accumulation further south toward I-70. && .UPDATE... Issued at 741 PM CST Fri Jan 6 2023 A narrow clear slot has spread across the center of the forecast area generally between I-74 and I-72 this evening. Model cross- section would suggest this should persist a good portion of the night. A ribbon of mid-level clouds from Peoria northwest also is fairly narrow. Question will be with the area of stratocumulus that appears to be oozing southwest out of northern Illinois. Latest HRRR is backing off some on the speed, though it does show it spreading south to near I-74 by 3-4 am. Did some tweaking of the sky forecasts to back off a bit on the cloud cover across the heart of the forecast area overnight, but increasing it again late tonight from the north. && .SHORT TERM...(This evening through Saturday) ISSUED AT 302 PM CST Fri Jan 6 2023 High pressure will dominate the weather across central Illinois over the next 24 hours...bringing partly cloudy skies and very light winds. Several CAMs suggest patchy fog development along/north of a Macomb to Bloomington line tonight, so have added fog to the northern KILX CWA accordingly. After any early morning fog dissipates, partly sunny skies will prevail until late afternoon when clouds begin to increase/thicken from southwest to northeast across the area. Lows tonight will mostly be in the middle to upper 20s, with lowers 30s south of I-70. Highs on Saturday will range from the middle 30s far north around the middle 40s south of I-70. && .LONG TERM...(Saturday night through Friday) ISSUED AT 302 PM CST Fri Jan 6 2023 Short-wave trough evident on 20z/2pm water vapor imagery over Colorado will track slowly eastward over the next 24-36 hours, eventually passing through central Illinois during the day Sunday. The corresponding surface low will track well to the south...from southeast Colorado presently to western Kentucky/Tennessee by Sunday morning. Light wintry precipitation associated with this system will begin to spread into parts of central Illinois late Saturday afternoon into the evening: however, it will be battling a dry E/NE boundary layer flow, so think it may not precipitate along/north of I-74 until around midnight at the earliest. The most widespread precipitation will hold off until stronger forcing associated with the short-wave arrives Sunday morning. Thermal profiles initially support very light snow or a rain/snow mix during the evening before a transition to mostly snow overnight into Sunday morning. As an elevated warm layer aloft pivots northward, a zone of mixed precip may develop near the I-70 corridor by morning. Any freezing rain that occurs will be light, short-lived, and falling in borderline temps. As a result, am expecting little to no icing. Further north, snowfall amounts look to remain under 1 inch along/north of I-72. Will need to keep an eye on possible banding, with isolated amounts possibly exceeding 1 inch. The wintry precip will taper off from west to east during the afternoon with high temps climbing well above freezing everywhere. Think there will be slick spots on untreated and secondary roads Sunday morning, but any snow/ice on the roads will melt by midday as temps rise above freezing. Once the short-wave departs, a period of mild and dry weather will prevail Monday through Wednesday before a more significant storm system takes shape for the end of the week. Temps will be well above normal for this time of year in the middle to upper 40s throughout the extended. As a result, rain is anticipated Thursday/Friday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 524 PM CST Fri Jan 6 2023 Main aviation concern will be with potential for MVFR ceilings toward early Saturday morning. Currently seeing ceilings below 2,000 feet across northern Illinois, with some of the high-res models suggesting a southwest push overnight. NBM and HREF show probabilities of ceilings below 3,000 feet around 40% from KPIA- KCMI toward 11-12Z, though the HRRR cloud height guidance is much faster and further south. Will only include that particular corridor for now with TEMPO potential for ceilings around 2500 feet, but will continue to monitor trends the next several hours. Improvement is likely toward late morning. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Geelhart SYNOPSIS...Barnes SHORT TERM...Barnes LONG TERM...Barnes AVIATION...Geelhart
Area Forecast Discussion
National Weather Service Memphis TN
851 PM CST Fri Jan 6 2023 ...New UPDATE... .UPDATE... Issued at 835 PM CST Fri Jan 6 2023 A band of cooler dewpoint temperatures is currently in place stretching from Memphis to Jackson, TN. As a result, dewpoints were lowered in this area through 06Z. In addition, cloud cover has increased west of the Mississippi River as a deck of mid- level clouds moves in from the west ahead of a cold front. Overnight, rain chances will increase with areas in northeast Arkansas and northwest Tennessee likely to see showers by morning. Showers will continue to move south tomorrow, with a few rumbles of thunder possible south of the Tennessee / Mississippi stateline. Otherwise, temperatures Saturday will vary as the cold front pushes through. Upper 40s to low 50s are forecast for northeast Arkansas and northwest Tennessee. Southwest Tennessee and north Mississippi will trend warmer, with highs in the upper 50s to low 60s. ANS && .SYNOPSIS... A few rounds of showers, and perhaps a few thunderstorms, are expected across the Mid-South this week. One system will affect the area beginning tonight and continuing into early Sunday as a cold front moves through the region. The next significant potential for rain will be late next week. Seasonal temperatures are expected much of the next 7 days. && .DISCUSSION... (This evening through next Thursday) Issued at 236 PM CST Fri Jan 6 2023 The CONUS remains within a split flow pattern this afternoon with fast, quasi-zonal flow aloft over the Mid-South. A slow-moving trough is traversing the Southern Rockies, passing beneath an upper-level ridge nosing into the Prairie Provinces. A weaker shortwave trough is approaching the Baja Peninsula with a strong subtropical jet emanating across the Southwest. Large-scale forcing for ascent will overspread the area tonight, aiding in the development of light rain showers after midnight. Mesoscale forcing will be enhanced via low-level frontogenesis beneath a convectively unstable layer around 700 mb. This precipitation will move gradually south late tonight into Saturday morning. A few rumbles of thunder are possible on Saturday, mainly from Memphis south, though the severe weather threat remains very low. A surface low will move across the Mid-South Saturday night as the upper-level trough over the Rockies sweeps across the Midwestern states. Showers and thunderstorms will be most likely along and south of a cold front attendant to the surface low, primarily over north MS and portions of West TN. Total QPF is expected to remain less than 1" in most areas, though localized higher amounts will be possible within any convective elements that develop. Most of this activity will clear the CWA by Sunday morning, leaving generally benign weather heading into early next week as shortwave ridging develops over the region. Another shortwave trough will move across the area Monday night into Tuesday, pushing another weak cold front through the Mid- South. Ensemble guidance isn`t exactly bullish on rain chances with this system but both the deterministic GFS and ECMWF offer light QPF Tuesday morning. This was worth a slight chance for showers across north MS and portions of West TN. Regardless, QPF looks to be fairly light given the general dearth of moisture (precipitable water ~0.50"). Once this system passes, we`re looking at 36 hours or so of pleasant weather with system temperatures. However, a late week trough will bring rain chances back into the forecast by Thursday, continuing into Friday. This system currently appears to lack in instability, keeping the potential for significant convection low. && .AVIATION... (00Z TAFS) Issued at 553 PM CST Fri Jan 6 2023 VFR to prevail for the better part of tonight, as mid and upper level moisture spreads through the region, in advance of an upper level disturbance lifting through the Ozarks. Marginal LLWS will precede this disturbance, affecting all but TUP overnight. MVFR potential will increase at all but TUP following sunrise Saturday, as showers become more widespread. TSRA potential should hold off until late Saturday afternoon. 18Z HRRR model depicts TSRA in the southern MEM TRACON by 00Z/08, with the terminal dropping to IFR on the cool side of a surface front. PWB && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...MJ AVIATION...PWB
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
611 PM CST Fri Jan 6 2023 .DISCUSSION...(This evening through Friday) Issued at 234 PM CST Fri Jan 6 2023 KEY MESSAGES: (Same as previous discussion) - Light winds and a stagnant airmass will allow for the potential development of fog and low stratus each day into early next week. - Next chance of snow arrives mid to late next week, though nothing major at this time. TODAY AND THROUGH SATURDAY NIGHT - Early afternoon satellite imagery with metars and RAP surface analysis showed partly cloudy skies across the Upper Midwest, with a few areas of fog and light snow showers beneath a very thin stratus deck in some locations. Surface high pressure was in place, meaning very light winds and seasonably cool temperatures. The main story over the next 36 hours is the high likelihood of fog develop again later this evening into Saturday morning given the synoptic setup outlined above. HiRes models are in good agreement that visibility will drop down to near 1/4 mile in a few locations, so have continued with expansive fog wording in the weather grids, and should have low stratus expand as well. There is a chance a dense fog advisory may be needed, but since this is radiation fog will hold off and wait for more guidance in order to see the trends. This fog will be slow to clear out on Saturday as high pressure remains in place but southerly winds will start to develop later in the day which should promote some mixing. There is a chance for some fog to redevelop again Saturday night, with the greatest chance east of I-35. SUNDAY THROUGH FRIDAY - A prolonged stretch of dry weather with warmer temperatures continues Sunday into early next week. Winds still remain light, so as mentioned in the previous discussion, could see a repeat of fog/stratus into early next week. Temperatures moderate a bit, with highs on Monday in the 20s west, and near 30 east. Looking ahead, a split upper level trough will approach the region Wednesday, and this will bring a chance for some rain/snow chances later in the week. Chances are small (10 to 30 percent) with the highest percentage in eastern Minnesota and western Wisconsin. Temperatures will remain in the mid 20s to lower 30s, with lows generally in the teens. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 547 PM CST Fri Jan 6 2023 We will have a moist and stagnant airmass again tonight, with freezing fog again likely. How widespread it will be, when it will set in, how long it will last are all a bit unknown. At this point, we already have a good collecting of MVFR or low VFR vsbys out there, so decided to lean toward the short term guidance, which are all really aggressive with fog development tonight. Like this morning, any fog we do see will be slow to improve given the light winds and low sun angle leading to an environment with weak mixing. Saturday night looks to be more of the same with the exception of western MN, where a weak return flow will be setting up. KMSP...Decided to lean toward the HRRR/LAV in bringing fog into MSP, this is not a high confidence forecast, but we`re certainly primed to see dense fog really slow things down the start to Saturday and Sunday as well... /OUTLOOK FOR KMSP/ SUN...VFR. Chc MVFR/IFR w/AM FZFG. Wind S 5-10kts. MON...VFR. Wind SW 5-10kts. TUE...VFR. Wind NE 5-10kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...JRB/BPH AVIATION...MPG