Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/07/21


Area Forecast Discussion
National Weather Service La Crosse WI
400 PM CST Sat Mar 6 2021 .SHORT TERM...(This evening through Sunday) Issued at 140 PM CST Sat Mar 6 2021 Warmer temperatures are on the way for Sunday along with stronger winds. The area of high pressure currently extending from western Ontario into the mid-Mississippi River Valley will work slowly off to the east tonight and Sunday. This will allow a cold front to emerge from the Rockies and tighten up the pressure gradient over the region for Sunday. The winds will respond to this with gusts of 20 to 30 mph out of the south/southeast expected for a good share of the day. These winds will bring in warmer air with highs expected to top out from the middle/upper 40s to the upper 50s. A chance that some locations of northeast Iowa that are snow free could briefly touch 60. .LONG TERM...(Sunday night through Saturday) Issued at 140 PM CST Sat Mar 6 2021 Warm and dry conditions continue through the early part of the work week. Wide and expansive ridging aloft is contributing to these above normal temperatures. The ridge slightly dampens Sunday night into Monday as a shortwave extending southward from northcentral Canada progresses eastward through the northern Great Lakes Region. Surface high pressure follows in its wake, which will relax surface winds Monday to briefly flow from the west. High pressure slides off to the east and the pressure gradient tightens increasing winds from the south on the back side of the high with possible wind gusts up to 25 knots by Tuesday afternoon. Decent warm air advection and a warm front passing through the region also aids in the warmer conditions. NAEFS and ECMWF ensemble standardized anomalies are near 2 standard deviations above the climatological mean for 850 and 700 mb temperatures by Tuesday afternoon. With all the supporting factors, Tuesday is still on target to be the warmest of the days with potentially breaking records as afternoon temperatures climb into the 60s. Under these favorable conditions, it is likely for temperatures to overachieve compared to the regular blended model guidance. Have decided to increase temperatures closer to the 75th percentile. Will have to watch out for cloud cover and any remaining snowpack that would limit the increase in temperatures. However, with temperatures remaining above freezing through the overnight hours for much of the area, the snow coverage will greatly diminish over these unseasonably warm days and nights. Widespread precipitation chances return Tuesday night, continuing through Wednesday, with chances lingering for some into Thursday. Afternoon temperatures are still expected to be above normal, but how high is still uncertain. Cloud coverage, precipitation, and cold frontal passage timing would all influence the temperatures. As near surface lapse rates steepen into the afternoon, there is a chance for isolated thunderstorms. GEFS plumes have mean CAPE values peaking in the afternoon around 50 to 200 J/kg across the region. However, no severe weather is expected. As for precipitation totals, ensemble guidance has mean QPF values around 0.25" across the region. After the cold front pushes through, temperatures should return closer to seasonable normals through the end of the week. Exact temperatures are uncertain as there is some decent spread between the model guidance. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 400 PM CST Sat Mar 6 2021 Cigs/wx/vsby: mostly some sct-bkn upper level clouds through the period, ahead of an approaching shortwave trough Sun. No pcpn expected with this feature. One thing to keep an eye on is the potential for pooling low level saturation Sun morning, ahead of the shortwave. The NAM (per usual) is aggressive here, suggesting mvfr cigs would develop. The RAP is fairly dry, as it most other models. In addition, source region of said low saturation not producing much cloud at this time - if at all (obs/satellite imagery). Will hold with VFR for now. Winds: winds will be on the increase by mid morning Sunday as pressure gradient tightens. Some gusts, but those will be limited by relatively shallow mixing due to strong warming a loft. Could see a few hours of LLWS concerns near 00z Mon. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...04 LONG TERM...Peters AVIATION....Rieck
Area Forecast Discussion
National Weather Service Grand Forks ND
652 PM CST Sat Mar 6 2021 .UPDATE... Issued at 652 PM CST Sat Mar 6 2021 Strongest gusts have diminished with at least some decoupling of the BL, however as LLJ develops and pressure gradient increases it appears likely that gusts will increase once again tonight. Depending on how deep we mix potential is there for some gusts around 40 mph (though this shouldn`t be too common). I made some adjustment to increase overnight winds to better reflect this. There is still a signal for stratus development (which could complicate mixing as well) and while some guidance indicates possible fog along and west of the RRV escarpment this is much less certain due to the winds/potential mixing. Will monitor evening trends. && .SHORT TERM...(This evening through Sunday night) Issued at 252 PM CST Sat Mar 6 2021 Main focus during the tonight through tomorrow night period will be gusty winds overnight tonight as well as the potential for patchy fog. Both are a result of the passage of a dry front late tonight into Sunday morning. South-southeasterly winds will remain elevated as a result of a tightening pressure gradient and mixing ahead of a shortwave trough and attendant dry cold front expected to pass through the Dakotas Sunday morning. Ahead of the trough develops a 50-60 kt LLJ overnight tonight into Sunday morning. The tightened pressure gradient will allow some of this jet to penetrate the nocturnal inversion, esp with the help of some terrain influences. Some CAMS and MOS guidance suggest gusts higher than 35 mph between midnight and 9 AM, although the nighttime lends to the thought of highest gusty winds to remain sporadic. There is also the potential for fog despite these gusty winds, especially near the western Valley. Guidance like HREF and HRRR have continued to highlight this area for fog potential. Confidence is increased in this potential through persistence forecasting within western and central ND where fog has been a persistent feature in a synoptically similar set up over the last couple of nights/mornings. Wind direction and increase in elevation also favors area. This will be a target of opportunity overnight tonight. Despite the shortwave passage, temps will remain unseasonably mild with lows staying above freezing (due to mixing and clouds) and Sunday highs remaining in the 50s, possibly 60s in southeast ND. Elevated westerly winds and later day WAA will aid in these temps as well. .LONG TERM...(Monday through Saturday) Issued at 252 PM CST Sat Mar 6 2021 Impacts in the extended period will come from a pattern change with southwest flow aloft developing then precip chances during the mid week as a couple shortwaves move through with more zonal flow expected for the end of the week. Ensembles are in good agreement with this overall evolution this week with details of timing and placement of smaller features yet to be determined. As a result the upper ridge will persist over the area to start the week and his will allow a continuation of well above normal high temps Monday and Tuesday with 50s and 60s expected. Will need to continue to watch for strength and placement of lead short wave possibly bringing scattered showers into NE ND Tuesday afternoon and evening along a cold front. By Wednesday temps will be much lower with rain/snow chances overspreading all but the Devils Lake region. The best chances in the forecast area of seeing a tenth of an inch or more of precip remain across the southern valley and into the lakes and trees area of MN where blended guidance suggests its only around 20 percent. Much of the guidance takes the majority of precip southeast of the area. The trend of any site within the CWA of seeing more than a tenth of an inch of QPF continues its downward direction. Temperatures Wed through Friday will range in the 30s and low 40s for highs. Still above the 30 year normals but much cooler than recent temps. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 540 PM CST Sat Mar 6 2021 Gusty southeast winds eventually turn to the southwest late tonight and then to the west-northwest as a front moves into the region Sunday. A strong 40-50kt low level jet tonight may result in low level wind shear, but could also result in a stronger period of winds with gusts 30-35kt overnight. VFR conditions across eastern ND and northwest MN eventually transitions to MVFR as stratus develops later this evening/overnight northwest to southeast. Eventually as the winds shift west stratus should start to improve/lift Sunday, but this might not be until the afternoon (west to east). There is some indication that fog may develop near central ND, but due to winds this is much less certain (stratus is favored). && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. $$ UPDATE...DJR SHORT TERM...CJ LONG TERM...JK AVIATION...DJR
Area Forecast Discussion
National Weather Service Louisville KY
934 PM EST Sat Mar 6 2021 .Forecast Update... Issued at 934 PM EST Sat Mar 6 2021 It will be a quiet, chilly night with high pressure in control. A weak upper wave will bring a few clouds. && .Short Term...(This evening through Sunday) Issued at 200 PM EST Sat Mar 6 2021 Sfc analysis shows broad sfc high pressure across the region today, leading to sunny skies, light winds, and temps in the mid-upper 40s with a few spots around 50F. There is an upper level trough currently swinging through the Ohio Valley region, but quiet weather will continue tonight. With a dry air profile overhead, we will remain dry, but could see some clouds develop around 5,000 ft this evening and tonight as a result. RAP soundings show a ~75% saturated 850mb layer at LEX and SDF during the overnight hours, so still expect to see scattered clouds for at least our north and northeast CWA. Temps will drop to the upper 20s and near 30F. For tomorrow, sfc high pressure will continue to be situated overhead. With the upper trough off to our east by then, cloud cover should be minimal or non-existent with NW flow aloft. Temps will spread from the upper 40s in the Bluegrass, to upper 50s/near 60F along our western CWA. .Long Term...(Sunday night through Saturday) Issued at 256 PM EST Sat Mar 6 2021 ...MILDER TEMPERATURES EXPECTED NEXT WEEK... ======================================== Synoptic Overview ======================================== Overall, we`re not seeing much change in the expected hemispheric pattern aloft for late this weekend and into next week. Upper trough axis over the eastern US is forecast to move off to the east while broad upper level ridging builds across the eastern two-thirds of the country. Ridge axis looks to be centered along the Mississippi River by early Tuesday with the axis of the ridge shifting towards the Appalachians by mid-late week. By mid-week, large closed low is forecast to drop into the southwestern US resulting in a split flow pattern across North America. The Ohio Valley will be under the broad west-southwest flow of the southern jet. This pattern will feature a warmer period of temperatures with increasing moisture by mid-late week. A frontal boundary is forecast to drop into the region by late week bringing periods of rainfall to the region from about Thursday through Saturday. ======================================== Model Discussion and Sensible Weather ======================================== Much of the early-mid part of the extended period will feature dry and increasingly mild weather. The overall trend in the guidance continues to edge slightly warmer as the models sense out the developing ridge. Highs Monday should warm into the upper 50s and lower 60s with mainly 60s across the region on Tuesday. Overnight lows should feature readings in the 30s. The milder surge of weather should be seen by Wed/Thu as temperatures warm into the mid- upper 60s with a few spots hitting 70+. Still seeing a spread within the model guidance with regards to precipitation chances in the late week period. The Euro continues to be most aggressive with bringing scattered showers into the region as early as Wednesday night, while the GFS v12 and v16 runs keep things dry through Thursday. In general, it appears that the best chances of precip would be mainly confined to areas north of the Ohio River in the Thursday to Friday time frame. Have gone ahead and used a blended approach here that keeps low chance PoPs in the forecast here. While details are still lacking, it appears that a better chance of rainfall exists in the Friday to Saturday time frame. The split flow pattern aloft will give the models fits and I expect continued oscillations within the guidance until upper pattern becomes more defined. The threat for moderate to heavy rainfall looks a bit less as the QPF fields from the models have decreased somewhat. However, given the wet grounds due to recent flooding, it would not take much rainfall to generate more hydro issues toward the end of the period. With the expected front slicing into the region on Friday, we do believe that we`ll see slightly cooler temperatures here. So plan on going with upper 50s to the lower 60s across southern IN and northern KY on Friday and Saturday with lower-mid 60s across southern KY. A look ahead shows a continued active pattern for the late weekend and into the early part of week two. A period of colder weather looks to arrive by mid-month. Teleconnection patterns still are not favorable for significant/sustained cold with a +AO/-PNA/+NAO pattern. However, the notable dip in the EPO is likely to result in a period of colder weather here. Not exactly sure how long the cool will last, but the MJO is progged to be in phase 1 mostly and that would favor cooler than normal conditions. However, this will depend mostly on the strength of the MJO and whether or not the La Nina background state ends up driving the pattern. ======================================== Societal Impacts ======================================== No significant societal impacts are expected during the period. Ongoing river flooding will continue across portions of the Kentucky, Ohio and Green river basins. Cresting in certain basins are expected this weekend and into early next week. Milder conditions are expected next week, but record highs do not look to be tied or broken. There is a slight risk that some warm overnight minimum records could be tied/broken. There remains a risk of moderate to occasionally heavy rainfall in the late week and weekend period. Given antecedent soil conditions, any rainfall would likely result in runoff and quick rises on creeks and streams will be possible Residents in low-lying and flood prone areas should keep an eye on forecasts next week. A return to colder conditions is still possible around mid-month (3/15 and beyond) and some wintry weather may be seen in some areas. ======================================== Forecast Confidence ======================================== Confidence of milder pattern next week : Moderate-High Confidence of late week hydro issues : Low Colder temperatures by mid-March : Low-Moderate && .Aviation...(00Z TAF Issuance) Issued at 541 PM EST Sat Mar 6 2021 No changes from previous Aviation Discussion... VFR conditions will remain over area TAF sites with high pressure in place, but expect some variability in wind direction. Tonight, a shortwave will likely carry a 4k to 5k foot scattered cloud deck from north to south through the area. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...13 Short Term...CJP Long Term...MJ Aviation...13
Area Forecast Discussion
National Weather Service Marquette MI
636 PM EST Sat Mar 6 2021 .SHORT TERM...(This evening through Sunday) Issued at 254 PM EST SAT MAR 6 2021 Current RAP analysis and GOES WV imagery continues to show an upper level low that is still over the Canadian Maritimes, allowing for a sfc high pressure to hold over the Upper Great Lakes. Position hasn`t really changed from yesterday but that will slowly change throughout the day. Northerly flow is still occurring which has been bringing in lake-effect clouds mainly from Marquette eastward, along Lake Superior. Drier air will filter into the area again, like yesterday, and will see clouds start to dissipate through the afternoon and evening. Winds will be relatively light tonight as the upper level low slides further east as ridging from over the northern plains will move closer to Upper Michigan, bringing in warmer air thanks to southerly flow. Winds could be a little breezy for Sunday with tightening of pressure gradient aloft. Not expecting any pcpn for this period but may have just a slim chance of some light pcpn over the Keweenaw late Sunday into Monday. Temperature will be similar again as to what they where yesterday, even with a few places overachieving by reaching the mid 40s. That may happen again today depending on the cloud cover since there is more of it today than yesterday. Given that, expect upper 20s to near 30 along the Lake Superior Shoreline and east where clouds hang on longer while mid to upper 30s and a few low 40s south and west. With clouds clearing and fairly light winds tonight, could get quite chilly especially over the interior west and east with good potential of seeing lows below zero in those areas tonight. Highs Sunday will be warmer with upper 30s to mid 40s over the central and west with good mixing and southerly flow, allowing for a good diurnal swing to occur in those areas with warming quickly through the morning. Wouldn`t surprise me if a couple spots did reach 50 degrees for a brief period. East will remain in the low 30s with southerly winds off Lake Michigan keeping it cooler out there. .LONG TERM...(Sunday night through Saturday) Issued at 304 PM EST SAT MAR 6 2021 Beginning Sunday night, mid-upper level ridge over the region will give way to more zonal flow as a weak shortwave moves in from the west. As with yesterday`s guidance, there still continues to be a weak precip signal due to increasing low level moisture. However, without deep moisture within the column, any precip would likely be light and be more of a drizzly-type precip. Soundings suggest some freezing rain could mix in, mainly in the central and east. These areas could see a light glaze develop overnight, especially if daytime temps don`t warm much. Overnight lows are generally expected to dip into the 20s. Following the shortwave`s passage, near zonal mid-upper level flow on Monday with a surface ridge gradually shifting east through the region is expected. With 850mb temps holding around +2C through the day within this dry airmass supporting mostly clear skies, I expect temps to soar. NBM 50th percentile has much of the west and southern UP near 50 degrees, with mid-upper 40s elsewhere. I suspect this may be under doing the daytime highs some given the model tendency to underachieve this time of year. Ended up trending daytime highs toward the 75th percentile. Monday night, the ridge will be to the east which will result in southerly flow eventually developing. This will lead stabilize temps and prevent them from falling too much. Generally lows dipping into the 20s is expected. Tuesday, with the southerly flow and WAA added into the mix, daytime highs should climb even higher. Again went higher on the highs, trending toward the NBM 75th percentile temps, which puts the west half of Upper Michigan above 50F. I woudln`t be surprised if some places got close to 60F. The east will stay a little cooler due to the moderating effects of the cooler Lake Michigan waters. Still though, I`m expecting mid 40s to near 50F daytime highs. With the day`s cloud cover lingering into the overnight period, lows in the mid-upper 30s is expected, with some low 40s in the south half along the WI/MI border. Overnight Tuesday, a low will eject out of the Plains and track northeast toward the Upper Great Lakes through the day on Wednesday. Precip is expected to overspread much of the area by afternoon and evening. The exact track of the low is still unknown, but GEFS solutions cluster the low by 0z Thursday primarily in northwestern Wisconsin or eastern Minnesota. This track would favor precip falling as rain, as the UP would still be under the influence of the WAA ahead of the system`s cold front. It should be noted though that if the low tracks further east, a rain/snow mix or perhaps all snow could be favored in the western UP. With PWATS increasing to 0.75- 1.15" over the region by afternoon, along with strong fgen and theta e advection, some moderate to heavy rainfall is possible. Following the low lifting northeast, CAA on the backside of the system`s cold front could result in precip transitioning over to freezing rain or snow. Given that this is still 4-5 days out, as we better identify the trends of this system, the sockdolager will come with subsequent forecasts. For folks looking for that spring xenium, dewpoints are expected to climb above freezing beginning Monday and linger through Wednesday. They should fall below freezing Monday night, but otherwise a few days of above freezing dewpoints are expected. With the warmer and more moist airmass, moisture from the air is expected to deposit onto the snowpack due to saturation vapor pressure differences. As this happens, latent heat release of the vapor phasing to liquid will lead to quick melting of the snowpack this week. On Wednesday, with the added moisture from the rainfall, this will likely result in patchy to widespread fog. Together these will likely result in some river rises and ponding on roads and low lying areas. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 636 PM EST SAT MAR 6 2021 VFR conditions at KIWD should continue for the TAF period, whereas KCMX and KSAW could see some MVFR cigs tonight as we could see a repeat of what happened last tonight at these TAF sites via lake- effect clouds. Expecting conditions to return to VFR by morning and continue for the rest of the day at KCMX and KSAW. Some LLWS should move through KIWD and KCMX Sunday afternoon as WAA moves through the area; KSAW may see some LLWS late in the TAF period as well, and should see some more after the end of this TAF period. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 254 PM EST SAT MAR 6 2021 North winds around 20 kts will slowly diminish across the east half of the lake through tonight and remaining below 20 knots through early Sunday morning. Winds will turn more out of the south Sunday mid morning and increase to 15-25 knots across most of the lake, except for the far western end. Could have some areas over the central and east get to 30 knots late Sunday afternoon and evening. There may be a few gale force gusts to 35 knots as well. Winds will fall below 20 knots for Monday and Tuesday before increasing to 20- 30 knots with some gale force gusts possible out of the south by late Wednesday ahead of next system moving towards the lake. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JH LONG TERM...JP AVIATION...TAP MARINE...JH
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
737 PM EST Sat Mar 6 2021 .UPDATE... The majority of the showers continues to push southeast as the area of low pressure moves over southern Florida. Some stray showers will be possible over the next few hours, but most of the area will remain rain-free overnight. Mostly cloudy skies will stick around tonight until strong high pressure moves in from the northwest allowing for drier and cooler air to filter into the region on Sunday. Temperatures tonight and on Sunday will come in a few degrees below average before the next warm up begins on Tuesday. Have tweaked the POPs over the next 6 hours to better reflect current radar coverage and HRRR guidance, otherwise forecast is tracking fine. && .AVIATION... Some MVFR conditions expected with BKN/OVC CU/SC through early Sunday morning, gradually clearing and becoming VFR on Sunday. Gusty north-northeast winds around 10-15 knots with higher gusts expected through the period. && .MARINE... Some stray showers will linger for the next few hours, clearing out by Sunday morning. A tightening pressure gradient between the area of low pressure over southern Florida and strong high pressure building in from the northwest will produce gusty northeast winds for the next 36 hours. This has warranted the issuance of a Small Craft Advisory for the eastern gulf waters including Tampa Bay and Charlotte Harbor through Monday morning. Conditions slightly improve by Monday afternoon, but boaters should still use caution through the week as some gusty easterly winds will be possible. && .Preliminary Point Temps/PoPs... TPA 55 71 48 72 / 30 0 0 0 FMY 58 76 51 75 / 30 0 0 0 GIF 54 70 48 71 / 30 0 0 0 SRQ 56 73 49 73 / 30 0 0 0 BKV 48 70 40 72 / 30 0 0 0 SPG 57 70 53 71 / 30 0 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...Small Craft Advisory until 1 PM EST Sunday for Coastal waters from Tarpon Springs to Suwannee River FL out 20 NM-Waters from Tarpon Springs to Suwannee River FL out 20 to 60 NM. Small Craft Advisory until 8 AM EST Monday for Coastal waters from Englewood to Tarpon Springs FL out 20 NM-Waters from Englewood to Tarpon Springs FL out 20 to 60 NM. Small Craft Advisory from 1 AM Sunday to 8 AM EST Monday for Coastal waters from Bonita Beach to Englewood FL out 20 NM- Waters from Bonita Beach to Englewood FL out 20 to 60 NM. Small Craft Advisory from 1 AM to 1 PM EST Sunday for Charlotte Harbor and Pine Island Sound-Tampa Bay waters. && $$ UPDATE/AVIATION/MARINE...74/Wynn UPPER AIR/DECISION SUPPORT...25/Davis