Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/11/21

Area Forecast Discussion
National Weather Service La Crosse WI
938 PM CST Wed Mar 10 2021 .UPDATE... Issued at 927 PM CST Wed Mar 10 2021 The line of showers and a few storms continues to move across far eastern Iowa and parts of western and central Wisconsin. Over the last hour, we have seen an uptick in gusty winds in southeast Minnesota 45 to 50 mph at RST/TOB. Decided to extend parts of the wind advisory until 09Z as it looks like the winds may hang on a little later. && .SHORT TERM...(Tonight through Thursday) Issued at 200 PM CST Wed Mar 10 2021 SEVERE THREAT THIS EVENING: decent clearing has developed ahead of an area of low pressure currently pushing into western IA, although has filled in somewhat with cu. Upper 60s temps and mid to upper 50s dewpoints were located in the warm sector, working northeast ahead of the low/sfc cold front. RAP SBCAPE results in a thin ribbon of +1000 J/k by 00z along the western edges of the forecast area, quickly falling off as the storm system moves east/loss of daytime heating. Shear is...robust. 30-40 kts of 0-1km shear with plenty of turning in that layer. Shear continues into the 3-6 km layer, but not as impressive as in the low levels. If there was more instability, this would get ugly awfully fast. As it stands, a few strong potential severe storms are possible, with SE MN/NE IA holding the higher threat (more instability). Overall timing roughly 4 to 10 pm, with the severe threat probably more so 4 to 7. Isolated tornadoes highlight the hazards, with winds then perhaps a bunch of small hail. Not sure the instability/low level lapse rates (and somewhat skinny cape profile) will be enough for inch plus hail. Updraft strength could be an issue. Not saying "no" though. In addition, RAP KRST showing a relatively healthy cap to deal with. Another issue to overcome. Overall, will be watching radar closely and don`t be surprised to see a few warnings. WINDS: After the storms sweep through by mid evening, the parent low pressure system tracks from southern MN into northern WI, exiting overnight across the northern great lakes. Strong winds a loft/near sfc with +60 kts 850 mb jet streaking ahead of the sfc low and tightening sfc pressure gradient on the southern/western side of it. RAP bufkit soundings suggest mixing down upwards of +40 kts at KRST while 50 kts hangs out just under 2 kt. Inversion/time of day will work against working down the strongest winds but gusts upwards of 45kts look reasonable for the open areas west of the Mississippi river, potentially across northwest WI. Will continue Wind Advisory in its current configuration with this mind (modify if becomes necessary). .LONG TERM...(Friday through Wednesday) Issued at 200 PM CST Wed Mar 10 2021 After the passage of the storm system later thu, quieter and cooler air will settle in for the weekend as a sfc high meanders overhead. Temperatures still looking to be above normal though. Winter hasn`t left quite yet though as the next storm system takes aim on the region for Sun night-Mon. Upper level shortwave trough slated to swing out of the desert southwest Sat, lifting northeast toward the eastern great lakes (but on a weakening trend). Sfc low holds well south of the region but with good west-east frontogenetic banding north of the low - across the local area. Decent fetch of 850 mb moisture transport will feed this lift, with some enhancement from the left exit region of a 300 mb jet max. Overall, the GFS and EC have been fairly consistent with placement/timing of this next pcpn maker across the area for the past several days. Bulk of the ensemble members support accumulating pcpn for the local area too. Bigger questions lie with what would fall. Colder temperatures will already be in place by the time this trough works into the region. Time/height x-sections via the GFS and EC (along with some sounding data) point to above zero sfc/near sfc temps and colder aloft - suggestive of more a rain/snow question rather than mixed (at least at this time). Currently, the GFS is the more aggressive with considerably more snow but a wide variety of outcomes (per GEFS ensembles). The EC would drop a few inches of snow, but much less. With a wide range of potential outcomes, confidence is pretty low in how it plays out. Pcpn looking likely, but amounts and exact layout are uncertain. Something to watch for sure... && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 540 PM CST Wed Mar 10 2021 Broken line of showers has pretty much cleared through RST at this hour and now sits on LSE doorstep. Thunder chances are very low and confined more to our north and south. Breezy southerly winds will quickly shift to the southwest this evening behind a passing front. Despite the gusts this evening, winds at 2000 ft will approach 50 kts so still expect up to a few hours of low level wind shear. Winds then ramp up behind the front with gusts of 25 to 35 knots, perhaps a bit stronger at RST. Satellite shows widespread MVFR to IFR cloud cover just off to the west, which will spread into the TAF sites later this evening. Strong winds gradually become more westerly overnight, slowly relaxing late tonight into Thursday morning. High pressure then gradually builds into the area on Thursday, ushering in a clearing trend towards midday and a return to VFR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...Wind Advisory until 3 AM CST Thursday for WIZ017-029-032>034. MN...Wind Advisory until midnight CST tonight for MNZ094-095. Wind Advisory until 3 AM CST Thursday for MNZ079-086>088. IA...Wind Advisory until midnight CST tonight for IAZ008-009-018-019. && $$ UPDATE...Zapotocny SHORT TERM...Rieck LONG TERM....Rieck AVIATION...Kurz
Area Forecast Discussion...Updated
National Weather Service Billings MT
607 PM MST Wed Mar 10 2021 .UPDATE... Updated forecast to expire Winter Weather Advisory for NE Bighorn Mountains. Light snow showers will continue over the mountains through around 03Z based on latest HRRR, but accumulations will be light. Other snow showers over the Beartooths/Absarokas and adjacent foothills will die out this evening due to loss of insolation. Lapse rates of 8 deg C/km were indicative of an unstable airmass, but lift was very weak and mainly orographic. A few other snow showers had formed E of KBIL, so had low PoPs in through 03Z for these. Also latest HRRR continued to bring patchy fog S behind a cold front later tonight. Stratus was visible behind the front in Canada in surface obs and on IR satellite. Fog/stratus looked to start around 08Z so pushed back start time in grids. Otherwise, forecast was in good shape. Arthur && .DISCUSSION... Tonight through Thursday Night... Satellite imagery shows a shortwave over SD/NE moving east, and a low off the coast of northern CA, leaving us under a broad region of below normal heights and weak flow aloft. 500mb temps to -35C in central MT allowing for instability snow showers to form over our mountains and adjoining foothills. Some of this shower activity could be briefly heavy but otherwise it will not be organized. A winter weather advisory remains in effect til 6 pm for the NE Bighorn Mountains, and while synoptic snowfall has pretty much ended, a couple more inches of snow is possible w/ the showers over the next few hours. Overall, snow showers will taper off during the evening. Looking to the north, there is a cold front moving into north central MT, supported by a Canadian shortwave and trailed by an area of stratus in southern Alberta into Saskatchewan. As this front moves south, we could see some low clouds and perhaps localized fog eke into our cwa beginning around 10z tonight (mainly KBIL north and eastward). The fropa may be followed by some flurries but otherwise better forcing and potential for snow showers looks to stay to our north. As the Canadian wave moves off to the east, warming temps aloft will reduce the instability and should prevent any diurnal showers tomorrow afternoon. Thursday night will be dry under rising heights within col region. Temps will be seasonable over the next 36 hours, with lows mainly in the 20s and highs in the 40s. JKL Friday through Wednesday... Mainly dry conditions and above normal temperatures are forecast Friday through the weekend with high pressure over the Northern Rockies, while a cut-off low to the south tracks from Arizona to southeast Colorado. There is a chance the cut-off low pushes some moisture far enough north to affect Sheridan County and some areas along the Montana/Wyoming border by Saturday night and into Sunday. This could bring some snow accumulations, but most of the area will be dry through the weekend. High levels of uncertainty remain with regards to what happens early next week. Latest trends are for the cut-off low to move east into the central plains, with upper troughing moving into the West. How these interact with each other will dictate our weather. There remains quite a bit of spread in temperatures and precipitation, with ensembles showing a variety of solutions. That being said, it looks like cooler and more unsettled weather are possible over the area early next week with chances for rain/snow showers. Highs temperatures are forecast to range from the 40s and 50s Friday, to mainly 50s for the weekend. Highs in the lower 40s to lower 50s for early next week. Low temperatures in the 20s to lower 30s will be common for the extended period. STP && .AVIATION... Snow showers will frequently obscure mountains late this afternoon and evening, while VFR prevails across lower elevations tonight. Early Thursday (08z-16z), there is potential for localized fog and broken MVFR ceilings from KBIL to KMLS and KBHK. Otherwise, VFR will prevail tomorrow. Arthur/JKL && .PRELIMINARY POINT TEMP/POPS... Thu Fri Sat Sun Mon Tue Wed ----------------------------------------------------------- BIL 025/047 026/053 028/053 033/055 031/053 031/048 029/047 10/U 00/U 00/U 10/B 11/B 23/O 21/B LVM 019/043 021/046 024/050 030/051 030/050 030/046 028/045 20/U 00/U 00/U 00/B 11/B 33/S 21/B HDN 022/046 022/054 026/055 030/055 029/053 027/049 028/047 20/U 00/U 00/U 11/B 12/R 23/O 21/B MLS 022/043 023/053 027/056 029/054 029/050 026/045 026/044 01/B 00/U 00/U 00/B 11/B 11/B 11/B 4BQ 024/046 023/051 028/052 030/050 028/048 026/046 026/044 00/B 00/U 01/U 21/B 11/B 12/S 11/B BHK 020/042 020/052 024/054 026/051 025/046 022/043 022/042 01/B 00/U 00/U 01/B 11/B 11/B 11/B SHR 020/043 019/046 023/045 026/046 023/046 022/043 023/043 21/B 01/U 12/O 32/O 12/O 23/S 22/S && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service Cheyenne WY
522 PM MST Wed Mar 10 2021 .UPDATE... Issued at 517 PM MST Wed Mar 10 2021 Let the Winter Storm Warnings and Winter Advisories expire this evening as most of the snow has ended with the first shortwave moving into the northern plains. Will send out updates to POP, temperature, and winds over the next few hours once the snow showers or flurries end shortly. Winter Storm Watch in effect for Friday and this weekend with the most severe conditions likely Saturday, Saturday night, and Sunday morning. && .SHORT TERM...(This evening through Friday) Issued at 300 PM MST Wed Mar 10 2021 ...One winter event winding down this afternoon. Another...potentially historic event taking shape for Friday through Sunday.... Currently...Surface low near Wheatland this afternoon with cold front extending southwest into northwestern Colorado. Snow band continues across the northern Nebraska Panhandle westward to Converse County. Still getting snow reported on mountain SNOTELS in the SNowy and Sierra Madre Ranges as well as Metars up near Douglas and Chadron. Decided to clear out most of the advisories across the southern CWA with the exceptions of the Snowy and Sierra Madre Ranges and Converse/Niobrara and northern Panhandle where warnings will be allowed to continue through 5PM. Off to our west across central California...our next low pressure system is moving on shore. Evening shift will need to monitor for fog development this evening as the snow that fell today had quite a bit of moisture content to it. Would say the lower elevations of the Panhandle and maybe Laramie would be the prime areas for fog tonight. Mainly dry Thursday for most of the day...but guidance begins to hint at qpf developing across our southwestern counties late Thursday afternoon. Upper low moves into southern Nevada and northern Arizona Thursday evening with difluent upper level flow over southern Carbon and Albany Counties. NAM...SREF and GFS all showing widespread QPF Thursday evening into Friday morning in this diffluent flow. ECMWF showing similar placement...but much less QPF. Given the pretty good agreement from the GFS...NAM and SREF QPF...decided to start a Winter Storm Watch for our western counties after 00Z Friday...spreading east to the Panhandle by 12Z Friday. .LONG TERM...(Friday night through Wednesday) Issued at 300 PM MST Wed Mar 10 2021 Key messages...Heavy snowfall is likely starting Friday afternoon. Prepare for impossible travel conditions starting Saturday morning into Sunday evening. Protect livestock, people, property, and pets. IMPACTS...Whiteout conditions, low visibility levels, and possible power outages. Blizzard conditions are possible starting Saturday afternoon into Sunday evening for the Nebraska Panhandle and Albany, Laramie, Platte, and Goshen counties. Saturday and Sunday`s snowfall will bring major impacts to the entire CWA across southeastern Wyoming and the western Nebraska Panhandle. Forecast confidence is medium with placement and duration of the low pressure system hovering in Colorado. The uncertainty continues for exact snowfall amounts and intensity of this system due to the forecast concerns of varying dynamics and the possibility of a barrier jet forming. Although it is still early, this system shows tight gradients and strong winds aloft will support strong surface gusts up to 35-40 MPH for the Nebraska Panhandle and southeastern Wyoming. A possible jet could develop along the Rocky mountain ranges which could enhance snowfall development especially with most models showing cold air aloft. Snowfall ratio were too high with the GFS so using a NBM/ECMWF blend, I created a sweet spot ratio across the CWA ranging from 11:1-8:1. If this set up continues on track, this will lead to record-breaking snowfall across the region. Potential 3-day storm total snow forecasts are significantly above maximum 3-day records for Cheyenne and Scottsbluff including the March 2003 snowfall event. In addition to snowfall and strong winds, temperatures continue below freezing in southeastern Wyoming and hover in the upper 30s for the Nebraska Panhandle into next week. Skies will remain overcast into Tuesday afternoon. A piece of energy cuts off the same low pressure system from the weekend which may lead to light snowfall again Tuesday although upper level moisture is not present at this time. Mild conditions are possible mid next week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 420 PM MST Wed Mar 10 2021 Snow has started coming to an end for the southeastern Wyoming terminals, and is expected to continually diminish this evening for the Nebraska Panhandle. Will still see some lingering show showers over the next few hours for the KCYS and KRWL terminals. Otherwise, KCDR should begin to lift from a IFR to VFR this evening as snow pushes out of the region, with mostly MVFR and VFR expected for the remaining terminals. Current HRRR forecast soundings do indicate a potential for some low-level fog with the widespread melting snow moistening up the atmosphere for KLAR and the Nebraska Terminals. However, confidence remains low with a lack of clear skies to promote good fog development. Went ahead and lowered visibilities for the time periods expected, and will continue to monitor current conditions for any corrections needed. && .FIRE WEATHER... Issued at 300 PM MST Wed Mar 10 2021 Minimal fire weather concerns as we have seen widespread snow and are looking at another widespread heavy snow event Friday through the weekend. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Winter Storm Watch from Thursday evening through late Sunday night for WYZ101>103-106>108-116>119. Winter Storm Watch from Thursday afternoon through late Sunday night for WYZ104-105-109-110-113>115. NE...Winter Storm Watch from late Thursday night through late Sunday night for NEZ002-003-019>021-054-055-095-096. && $$ UPDATE...TJT SHORT TERM...GCC LONG TERM...AW AVIATION...MD FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Des Moines IA
540 PM CST Wed Mar 10 2021 ...Aviation Update... .DISCUSSION.../Tonight through Wednesday/ Issued at 137 PM CST Wed Mar 10 2021 145 PM CST Update on Severe Weather: SPC has issued an MCD recently, so will not provide a lengthy update here but just hit the highlights for this AFD issuance. Instability continues to build across central Iowa, and day-cloud phase satellite imagery is showing a cumulus field attempting to develop across central Iowa. As of 1930z, there were some weak radar reflectivities in northwest Iowa. Lapse rates continue to steepen, maintaining an a favorable thermodynamic environment. The MCD at 1933 UTC from SPC states a watch may be needed this afternoon. The next section will repeat the 1741 UTC AFD update from today. Previous AFD Update from 1141 AM CST Today: Short-wave trough and deepening surface cyclone continue to move northeast, currently located over eastern Nebraska. Pre-frontal surface troughing extends from northwest Iowa into southern and southeastern Minnesota as of 1715z. As was noted overnight by GOES- 16 visible satellite imagery, a prominent dry slot has been moving through over the warm-sector of the cyclone. Visible satellite imagery shows mostly clear skies for southwest Iowa, with cloud cover diminishing across central and northern Iowa. With this clearing, insolation will allow the convective boundary layer to destabilize ahead of the convergent boundary in an area of stronger convergence. At 1715z, SPC mesoanalysis depicts a bullseye of SBCAPE of 1000 J/kg in west-central Iowa, with 500-750 J/kg expanding toward the northeast within the pre-frontal surface troughing region. With insolation and the continued push of rich theta-e air, expect SBCAPE values continue to rise and spread eastward over the next few hours ahead of the convergence. 14z-15z runs of the HRRR favor SBCAPE values reaching as high as 1500-1750 J/kg over the next few hours, and this trend seems reasonable. This is higher than what the HREF mean had been depicting over the past 24 hours. Dewpoints have also been steadily rising from the mid 40s into the mid and upper 50s. There was some concern earlier that robust mixing with the gusty winds may create too dry of an environment, but as the convective boundary layer evolved this afternoon moisture does not appear to be in short supply. The vertical wind shear environment remains strong, this was never in question as is typical with early spring convective developments. 0-6 km bulk shear ahead of the convergent boundary is 50-60 kts. RAP and HRRR analysis indicate 0-1 km SRH for right moving supercells to be in excess of 200 m^2/s^2 ahead of the boundary, and 0-500m SRH around 100 m^2/s^2. Given this environment, all severe threat types are possible this afternoon and early evening, from hail, damaging winds, and a tornado or two could spin up in this environment. As for timing of initiation and eventual evolution, this is still a bit hard to pinpoint at the current moment. Recent runs of the HRRR have initial development in the far northwestern portion of the forecast area between 18-19z, but quickly move these storms into southern Minnesota. If updrafts do go at this time, the environment is there to help get them spinning and could produce hail and maybe a brief spin up. The window though for this happen in areas such as Emmet, Palo Alto, and Kossuth Counties will be narrow. Later this afternoon then, convergence increases across central Iowa along much of the Interstate 35 corridor. Recent runs of the HRRR over the last couple of hours have pulled initiation further north and west, and about an hour earlier to around 23z. With the instability that has developed in the strong shear environment, a couple of discrete supercell thunderstorms are possible in central and east-central Iowa this afternoon into the early evening. Again, all severe threats are possible close to the initiation time of thunderstorms. But, deep layer shear by early evening begins to align more parallel to the convergent boundary, and as noted in most of the CAMs since 12z develops more into a broken squall-line. As this evolves into a squall-line, the hail and tornado threat will decrease, but still could result in severe wind gusts through the evening in east- central Iowa, and perhaps southeast Iowa. The 1630z SWODY1 from SPC highlights this with the expansion of the slight risk. With strong flow, these storms and the eventual linear system will move rather swiftly, in excess of 50 kts. Over the next few hours, will continue to monitor the moisture transport, the surface wind field, and the instability. The areas of interest in the middle of the afternoon will be the far northwest Iowa, and then late afternoon early evening for central and east-central Iowa. Thursday and Beyond: Short-wave trough moves away from the region, while deeper trough develops into a broad closed low at H5 in the western CONUS. Weak ridge develops across the central Plains to just west of the Great Lakes Region, which will allow surface high pressure to build Thursday into Friday. The center of it will move through Thursday Night into Friday morning. This will clear skies out, and bring in slightly cooler temperatures with light north to northwest flow. There is another wave within the flow that moves across Missouri that may generate some precipitation there, and may just clip the far southern counties Friday Night. However, with the high pressure developing, there is decent probability this forcing gets pushed even further south. Do not anticipate much in the way of accumulation if precipitation does occur in far southern Iowa Friday Night. Ridge amplifies some as the closed low slowly propagates eastward. Expect clouds to be on the rise advecting from the bigger system out west. By Saturday evening, precipitation shield will start working toward the region, which may bring rain showers to southwest and west-central portions of the forecast area. This will increase in coverage Sunday into Monday as this system moves into the central Plains and upper Midwest. Models again are not showing the best agreement with the timing and track of this closed low system, and within the ensemble members QPF placement is not consistent. Accumulating snowfall could be possible if the deformation zone aligns favorably, by the end of the weekend and start of the work week. After the passage of this system, colder air will move into the region, and expect temperatures for much of next week to be below normal. The good news is that it is March below normal, not February, thus although temperatures will be colder they will not necessarily be brutal cold. The overall pattern is still somewhat active through next week, expect multiple periods of precipitation. && .AVIATION.../For the 00Z TAFS through 00Z Thursday evening/ Issued at 536 PM CST Wed Mar 10 2021 Main concerns will revolve around lingering convective activity the over the next couple of hours and then transitioning over to MVFR/IFR stratus potential. The main convective threats will be a KALO and KOTM. The primary MVFR/IFR stratus potential will be KFOD/KMCW with lesser opportunity at KDSM/KALO. Winds will also remain gusty, to 25 to 30 kts or greater out of the west, across the northern TAF sites much of this evening and into the overnight before easing early Thursday and settling out of the W/NW. && .DMX WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 8 PM CST this evening for IAZ033>039-046>050- 059>062-072>075-083>086-094>097. High Wind Warning until 8 PM CST this evening for IAZ044-045-057- 058-070-071-081-082-092-093. Red Flag Warning until 6 PM CST this evening for IAZ057-058-070- 071-081-092. Wind Advisory until midnight CST tonight for IAZ004>007-015>017- 023>028. && $$ DISCUSSION...Krull AVIATION...Curtis
Area Forecast Discussion
National Weather Service Quad Cities IA IL
555 PM CST Wed Mar 10 2021 ...00z AVIATION UPDATE... .SYNOPSIS... Issued at 214 PM CST Wed Mar 10 2021 A wind advisory remains in effect until 8 PM this evening. MSAS, surface analysis showed a surface low in northwest ILlinois with a stalled front stretching northeastward from the surface low towards MSP. A cold front stretching from the surface low southwestward into south central Nebraska. A dryline stretched southward along the Iowa and Nebraska border then is turns southwestward into Kansas then into southwestern Oklahoma and into West Texas. Across the local area, temperatures ranged from the lower 60s along the Highway 20 corridor to the upper 60s south of Interstate 80. KMLI was the warm spot at 70 degrees. Strong southerly winds sustained at 20 to 30 MPH with gusts up to 40 MPH. Skies were clearing ahead of the dryline across central Iowa with temperatures in lower 70s. && .SHORT TERM...(This Evening through Thursday) ISSUED AT 214 PM CST Wed Mar 10 2021 The main forecast concerns have been winds and the potential for severe weather. Models are in good agreement but CAMs have a better handle on the severe weather potential for today. Models are in good overall agreement that the surface low currently in northwest Iowa will track northeastward and into southwestern Ontario by 12 UTC on Thursday. This will drive a cold front across the area tonight. Models prog the cold front moving across eastern Iowa, northeast Missouri, and northwest Illinois between 00 UTC and 06 UTC. Ahead of the front, warming as clearing spreads into eastern Iowa and northwest Illinois late this afternoon and into this evening before sunset will allow for more mixing and may increase winds slightly this afternoon and into this evening. Model soundings show the potential for mixing higher winds down to the surface so wind gusts up to 45 MPH are possible before gradually decreasing behind the front with the pressure gradient decreasing in the wake of the low during Thursday morning. Temperatures on Thursday will be noticeably cooler. Expect thunderstorms to develop late this afternoon ahead of the front and continue across the area this evening with most storms exiting the far eastern end of the CWA in the 6 to 9 UTC timeframe. Please see the previous update issued earlier. Previous Update Guidance and obs are pointing to a better environment for HSLC severe threat this evening across the area. Insolation and breaks in the clouds in the clear slot are leading to the development of surface instability. With the system already shear heavy the environment is supportive of a conditional severe threat. While it looked like the main threat was winds earlier, the threat for tornadoes appears to be increasing for the following reasons. 1). CAPE that develops is concentrated in the lower levels of the atmosphere. As a result of this, the updraft will be shallower and will have the bulk of the llvl shear to tilt. This shear will lead to updraft rotation in the llvls increasing convergence in the lowest levels. There is also 0-3km CAPE that would be supportive of tornado development 2). The shear is impressive and the H85 LLJ strengthens across the area from 00z to 03z. This strengthening of the LLJ will increase shear and subsequent storm updraft and intensity. This will only aide in convergence at the sfc. The 0- 0.5km shear of near 30knots is impressive and will help to create frictionally generated vort in the low levels. If the HRRR is correct and we stay S at the sfc with winds, we will have more than sufficient directional shear for a tor. Even so, if we have a long lived mesovort with less directional shear that could pose a tor threat as well. Regardless, these storms will pose a damaging wind threat across the area. Any mesovort that develops will bring chances for winds up to 70 mph. The HRRR is the most aggressive with storms, yet has been extremely consistent for the last 7 to 8 runs, increasing confidence in its solution. The tornado threat, while increasing, is completely tied to the sfc wind direction and mesovort longevity. The wind threat continues to be the main threat from these storms. .LONG TERM...(Thursday Night through Wednesday) ISSUED AT 214 PM CST Wed Mar 10 2021 Key messages: 1. Active period with cooler temps through the long term period. Discussion: Active period as a cutoff upper low across the SW US eventually ejects across the Plains through the weekend. As this feature shifts east with time, additional shortwaves advect into the backside of the trof and provide chances for pops through the extended. This large trof will bring cooler temps to the area and a chance for mixed precip this weekend. A lot is still unknown with the thermo fields for this weekend so confidence in Ptype is low. With the highly energetic momentum fields, expect forecast skill to be low, so while there are chances for precip, exact timing and intensity will likely change through the period. && .AVIATION...(For the 00Z TAFS through 00Z Thursday Evening) ISSUED AT 548 PM CST Wed Mar 10 2021 Strong LLVl wind fields and turbulent airmass continues in place, and will time a short 1-2 hour tempo window at each site this evening for walking through a line of thunderstorms along an incoming front. CIGs may still stay VFR as these storm pass by or brief bouts of MVFR, but rain or wind blown rain reduced VSBYs may go to passing bouts of low MVFR or even IFR at times. Then behind the storms, a temporary dry slot clear window with sfc winds going west-southwest and still gusty to at least 25 KTs. Hopefully no gravity wave rear storm-line enhancement boosting winds even higher. Will go brisk variable winds of 25-30 KTs and gusts to at least 38-40 KTs in the TEMPO groups with the stronger passing storms, but they may be higher. Later tonight with some decrease in west winds, will have to watch for a wrap around post-frontal MVFR stratocu deck getting into at least the CID and DBQ sites for at least Thu morning. CIGs should trend VFR by Thu afternoon. ..12.. && .HYDROLOGY... Issued at 315 PM CST Wed Mar 10 2021 Moderate within bank rises continue on area rivers as snowmelt from far northern Iowa and Wisconsin works its way south. A flood warning continues for the Wapsipinicon river near Dewitt. More tributary rivers are forecast to approach flood stage from the snowmelt late this week and over the weekend before falling early next week. Those locations are; Cedar river at Cedar Bluff and near Conesville Iowa River at Marengo, Columbus Junction, Wapello, Oakville and near Lone Tree Maquoketa river at Manchester Pecatonica river at Freeport Rock river at Como, Moline and near Joslin Ensemble runs suggest the Mississippi river may begin to approach flood stage due to snowmelt after March 15th. Weather prediction models continue to trend lower with the predicted rainfall through Thursday. Most of the area now looks to see 0.1 to 0.2 inches of rain which will soak into the ground. The heavier rainfall now looks to occur from central Missouri into the southern half of Illinois. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...Wind Advisory until 8 PM CST this evening for Benton-Buchanan- Cedar-Clinton-Delaware-Des Moines-Dubuque-Henry IA-Iowa- Jackson-Jefferson-Johnson-Jones-Keokuk-Lee-Linn-Louisa- Muscatine-Scott-Van Buren-Washington. IL...Wind Advisory until 8 PM CST this evening for Bureau-Carroll- Hancock-Henderson-Henry IL-Jo Daviess-McDonough-Mercer- Putnam-Rock Island-Stephenson-Warren-Whiteside. MO...Wind Advisory until 8 PM CST this evening for Clark-Scotland. && $$ SYNOPSIS...Cousins SHORT TERM...Cousins/Gibbs LONG TERM...Gibbs AVIATION...12 HYDROLOGY...DC
Area Forecast Discussion
National Weather Service Lincoln IL
809 PM CST Wed Mar 10 2021 .SYNOPSIS... Issued at 312 PM CST Wed Mar 10 2021 Gusty south winds linger into this evening, with gusts up to 45 mph possible. Rain showers and some storms spread in from the northwest overnight into Thursday. Overnight lows will be mild with values in the middle 40s to upper 50s. Some stronger storms capable of producing small hail and gusty winds are possible across southeast Illinois on Thursday. && .UPDATE... Issued at 808 PM CST Wed Mar 10 2021 South half of the wind advisory has been canceled early, as gusts in this area have dropped off to less than 40 mph. Still seeing some stronger winds across the north, especially along I-74 with recent gusts near 45 mph at Peoria and near 50 mph at Bloomington. HRRR drops off these higher gusts from southwest to northeast the remainder of the evening. Line of showers and thunderstorms currently extends from northeast Iowa into south central Kansas, just ahead of the cold front. Latest high-res model runs bring it to near Peoria toward midnight, with some breakup in the line as it approaches the I-55 corridor. RAP model shows 300-400 J/kg of MUCAPE lingering through the night with this line, though, so will keep a mention of some thunder continuing. Temperatures to remain very mild over most of the CWA overnight and may struggle to drop below 60 before sunrise, while upper 40s/lower 50s come into the Illinois River valley. Updated zones/grids have been sent. && .SHORT TERM...(This evening through Thursday) ISSUED AT 312 PM CST Wed Mar 10 2021 South winds gusting to 45 mph continue across the area, with a few 50+ mph gusts being reported in east-central Illinois where winds up to around 850 mb are mixing down. An area of surface low pressure located over western Iowa this afternoon will continue to lift northeast into the Great Lakes Region, bringing us our next shot of precipitation later tonight through Thursday night. A cold front will approach the area from the northwest late tonight, spreading widespread rain showers and scattered storms southeast through the area. Winds look to remain pretty gusty ahead of the front`s arrival with the LLJ enhancing itself this evening. Winds should lessen as the front moves through/LLJ backs down going into Thursday morning. Rainfall amounts look to be heaviest across areas along/south of I- 72, where 1.00 to 1.50" are expected, though locally higher amounts are possible where storms occur. This will likely result in rises on rivers across the south, with the Little Wabash River near Clay City forecast to reach flood stage by the end of the week. Not expecting any stronger storms late tonight, but as the front slides into central and southern parts of the forecast area come Thursday morning/afternoon, a few stronger storms are possible. CAPE looks to be very marginal with MUCAPE values generally less than 500 J/kg, but with the front present, around 50 kt of shear with decent turning looks to set up over far southeast Illinois. This paired with steep lapse rates will lead to a marginal threat for small hail and gusty winds in any stronger storms. && .LONG TERM...(Thursday night through Wednesday) ISSUED AT 312 PM CST Wed Mar 10 2021 The front sags south of the CWA going into Friday as high pressure builds in from the north, drying things out for a short period. Temperatures will be cooler, yet still warmer than normal on Friday with values in the 50s. Precipitation chances increase across southern counties Friday night into Saturday as a surge of WAA interacts with the stalled front over the Ohio River Valley/an approaching system`s warm front. Precipitation amounts with this wave will be on the lighter side and should remain confined to areas south of I-70. The next chance for precipitation for the entire area looks to spread in late Saturday night/Sunday morning as an upper low across the southwest CONUS tracks into the middle Mississippi River Valley. Differences in track and timing still exist with this system, but additional rainfall is expected. Temperatures in the long-term period will return back to seasonable values. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 534 PM CST Wed Mar 10 2021 Area of MVFR ceilings is impacting portions of east central Illinois early this evening, and ceilings will fluctuate around 3,000 feet through the evening. Wind gusts have begun to subside a tad, but will still gust at or above 30 knots a good portion of the evening. Some LLWS will still be an issue as the winds settle down a bit. A narrow line of showers/storms will approach KPIA around 06-08Z and KSPI/KBMI around 08-10Z. Storms should be in a weakening state, so did not mention thunder at KDEC/KCMI at this time. With the rain, ceilings around 1500 feet should become more widespread, lingering into Thursday afternoon as a cold front pushes across the area. && .ILX WATCHES/WARNINGS/ADVISORIES... Wind Advisory until midnight CST tonight for ILZ027>031-036>038- 040>048-053. && $$ UPDATE...Geelhart SYNOPSIS...NMB SHORT TERM...NMB LONG TERM...NMB AVIATION...Geelhart
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
919 PM CST Wed Mar 10 2021 .UPDATE... 907 PM CST The strong low level jet core has shifted over northeast IL and northwest IN this evening, thus while some areas have slightly decoupled, area temperatures in the lower 60s has maintained mixing even into the evening hours. Sustained winds in excess of 30 mph continue to be reported at times and Chicago Midway just recently had a 49 MPH gust. Therefore we will continue the wind advisory through the evening hours ahead of the approaching cold front in spite of numerous areas holding winds in the 35-45 mph range. The compact upper low is across MN with a strong PV anomaly nosing into it across the plains. This vorticity max is driving and area of showers and embedded thunderstorms ahead of the cold front in Iowa. The stronger forcing is nosing into MN and thus radar echoes have been less deep and a noted lowering of dbZ core at -10C has occurred and thus a significant drop off in lightning. This lines up well with RAP guidance indicating some weakening of the CAPE axis. Still, DVN Oz sounding does have some elevated instability above a 800 mb inversion and lapse rates approaching 8 C/km. Thus it is conceivable that this line holds at least a few rumbles of thunder as it moves into the remainder of the area late this evening, and may actually see an uptick along and SE of Chicago as the upper jet noses in overnight. ILX also has some elevated instability to higher based air parcels. KMD && .SHORT TERM... 337 PM CST Through Thursday night... We`ve got ourselves another balmy mid-March afternoon out there today with mid-afternoon temperatures across the area mainly in the mid and upper 60s with even a few 70s here and there. This is unfortunately as warm as we are going to get for a while as a cold front will come through tonight and bring temperatures back down a bit with highs expected to stay in the 50s and lower 60s tomorrow. Prior to that though, we`ll all but certainly break two more records today with the March 10th record high minimum temperatures for both Chicago and Rockford on track to fall when the clock strikes midnight tonight. The record high (maximum) temperatures for both cities are also in jeopardy of at least being tied, but it`ll be a close call to see if both cities can reach 70 in the next hour or two before temperatures begin to descend later this afternoon. More information about today`s daily climate records can be found in the Climate section of the AFD further below. While the temperatures are certainly headline-worthy, its been the winds today that have been the main story for us so far. A tight surface pressure gradient associated with a deepening low pressure system currently over northwestern Iowa has allowed sustained winds of 20-30 mph to be a common occurrence across the CWA, and with skies having cleared a bit to allow solar insolation to aid in surface heating, we`ve been seeing wind gusts starting to pick up over the past few hours with several 40+ mph gusts already clocked at some of our observations sites south of I-80. In fact, just south of our CWA, Champaign Airport (KCMI) reported a recent peak gust of 52 kts (60 mph)! The stronger 40+ mph gusts will spread northward into the Chicago metro later this afternoon and evening, with at least sporadic 50+ mph gusts appearing quite achievable as well given the observations that we have already seen and that the low level jet won`t really get cranking for a few more hours here. The greatest likelihood for 50+ mph winds will generally be concentrated southeast of I-55 where steeper low-level lapse rates will be present. Winds will gradually cease through the evening and will turn more westerly by tomorrow morning in the wake of tonight`s cold frontal passage. The aforementioned potent low pressure system will continue to churn its way off to our northwest as we head into tonight. The cold front draped off to the southwest of the surface low will eventually encroach upon our area tonight, bringing some rain showers with it as well as a good chance for many to experience their first thunderstorm of the calendar year. The actual cold frontal passage won`t occur until around midnight for our western counties and will come closer to daybreak Thursday for our southern and eastern counties. Convergence along the frontal boundary will be the primary forcing mechanism at play, allowing for convection to bubble up over Iowa later this evening and track eastward into our area along the cold front. However, with the left exit region of the southern stream jet beginning to nose its way over the area and additional confluence expected out ahead of the front amidst plentiful moisture within a climatologically high 1.0-1.4" PWAT plume, additional showers could also sprout out ahead of the main line of showers and thunderstorms tonight, mainly southeast of I-55. MUCAPE up to around 500 J/kg and decent deep layer shear should allow for some degree of organized thunderstorm activity tonight through tomorrow afternoon. Some thunderstorms could feature gusty winds and maybe even some small hail, but should remain below severe limits. As the front becomes more west-to-east oriented across our southern CWA, we`ll also need to watch the potential for training thunderstorms, which could potentially produce a swath of 1-2" or so of rain somewhere south of I-80 if things align favorably for that, but overall potential for flooding remains fairly low given that we`ve melted just about all of our snowpack and that the soils across the areas with the greatest potential to see heavier rainfall are fairly dry (D1 drought stage has lingered around and just south of the Kankakee River Valley for several months now). Any lingering showers across our far south should cease by Thursday evening. High pressure will build in from the north and keep us dry into the night while overnight temperatures drop generally into the low-mid 30s. Ogorek && .LONG TERM... 202 PM CST Friday through Wednesday... The main focus of interest during the period will center on the evolution of the large upper low expected to shift from the southwestern CONUS out over the central Plains later this weekend. This system could impact our area later in the weekend into early next week, with rain and possibly even some wintry weather as well. At the start of the period on Friday, a surface high is expected to shift into the western Great Lakes. This should result in a fairly quiet weather day across the area. High temperatures should top out in the middle 50s inland, but due a northerly wind likely shifting off the lake during the day, much cooler conditions (in the low to mid 40s) are expected near the lake. The period of dry weather looks to continue on Saturday as the surface high settles over southern Lake Michigan. Dry low-level east-northeasterly flow, emanating from this surface high, should hold any precipitation well to our southwest through at least Saturday evening. Expect temperatures on Saturday to once again be the coolest along the lakeshore due to onshore winds. Our next period of potential inclement weather looks to be sometime Sunday through Monday as the aforementioned upper low shifts eastward across the central Plains. Forecast guidance continues to suggest that this system will be in a weakening state into Monday as it approaches the lower Missouri River Valley. This adds uncertainty to the the extent of precipitation the area will experience, particularly later Monday into Monday evening. Traditionally the evolution and track of upper lows can be difficult to pin down beyond a couple of days, so we will have to continue to monitor model trends with this storm system. As of right now it appears our best potential period of precipitation from this system will be sometime later Sunday and on Monday. This appears to be the period in which the weakening systems moist conveyor belt converges over the area. The main uncertainty for this period is if any lingering dry low- level air acts to inhibit precipitation from making it into northern IL. With this possibility, I did not stray from the NBM blended guidance for the probability of precipitation, which is generally in the change range (30-50%) for this time period. Precipitation type could become tricky into Monday, especially if the forcing for ascent continues to be adequate during the day. Thermal profiles indicate that snow, and or a wintry mix could occur over parts of the area as the column cools overhead with the approaching upper system. The threat for any decent snow will be conditional on there being some heavier precipitation rates, and at this time, the chances for this remain unclear due to the weakening nature of the larger scale storm system. KJB && .CLIMATE... A very mild air mass will be over the region through tonight. Here is a look at record temperatures at Chicago and Rockford for Wednesday, March 10. Wednesday March 10th .................... Record High for Chicago: 70 in 1955 (upper 60s forecast) Record High for Rockford: 70 in 1955 (mid-upper 60s forecast) Record High Min for Chicago: 52 in 1876 (lower 50s forecast) Record High Min for Rockford: 44 in 2010 (lower 50s forecast) && .AVIATION... For the 18Z TAFs... The main aviation weather concerns through this evening are wind- based, with a high likelihood of crosswind impacts on E-W runways. This will be followed by a brief window for precipitation late tonight. Surface observations late this morning have begun to show an uptick in gustiness across central Illinois where clouds are scattering and where the strongest low-level flow currently resides. Anticipate stronger south-southwesterly gusts developing early this afternoon as a result as this clearing continues to work eastward. Guidance suggests that winds at the top of the mixed layer are approaching 45 kts or so, and with some enhanced mixing, the latest thinking is we`ll start transporting some of this flow to the surface in the form of near 40 kt gusts towards 19-20z. By early this evening, there is a potential for winds to more routinely gust to near and above 40 kts, but the main question revolves around just how decoupled the near-surface layer becomes. Given the rather strong model agreement indicating increasing gusts this evening, have elected to prevail these stronger gusts until the front passes. Winds will favor a 190-200 direction this afternoon, and may veer slightly to 210-220 this evening which will likely continue notable crosswind impacts on E-W runways. Winds will subtly shift with the passage of a cold front late tonight. A narrow line of showers is likely to develop ahead of this. At this time, it looks like this activity will begin to outpace the main reservoir of better moisture and instability as it starts to enter the C90 TRACON and have refrained from a thunder mention as a result. The TS threat at ORD/MDW is non-zero, mainly during the 7-9z window, but is too low to justify an explicit mention. The TS potential RFD stands a somewhat better chance of TS--at least in the vicinity--and have maintained the PROB30 there as a result. Additional showers and embedded storms are likely to re-develop towards early Thursday morning, with increasing coverage south of MDW/GYY. Surface winds will veer northwesterly with time through Thursday afternoon, with gusts to 25-30 kts continuing. Carlaw && .MARINE...548 AM CST A Gale Warning remains in effect from 9 AM CST this morning (Wednesday) through early Thursday. Deep low pressure will track to the upper MS Valley by Wednesday evening, putting southern Lake Michigan in the windy warm sector of the storm system. Very mild air temperatures well in the 60s will lead to increasingly stable conditions over the lake. However, in these setups, the strong winds over land typically mix out into at least the first 1-3 miles of the nearshore waters. Current forecast has peak speeds up to 40 kt, but with forecast soundings on land pointing toward potential for occasional gusts approaching 45 kt. Thus continued to mention 35-40 kt prevailing speeds/gusts and 45 kt gale gust potential in the text of the nearshore, with areas over/closer to open waters remaining lower. Strong southwest winds will continue until cold front trailing the surface low sweeps across the area Thursday morning, with 25-30 kt speeds pre-dawn through mid morning. Hazardous speeds from a westerly direction may continue behind the front on Thursday afternoon. Castro && .LOT WATCHES/WARNINGS/ADVISORIES... IL...Wind Advisory...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011- ILZ012-ILZ013-ILZ019-ILZ020-ILZ021-ILZ023-ILZ032-ILZ033- ILZ039-ILZ103-ILZ104-ILZ105-ILZ106-ILZ107-ILZ108 until midnight Thursday. IN...Wind Advisory...INZ001-INZ002-INZ010-INZ011-INZ019 until midnight Thursday. LM...Gale Warning...nearshore waters until 4 AM Thursday. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Marquette MI
1027 PM EST Wed Mar 10 2021 .UPDATE... Issued at 1026 PM EST WED MAR 10 2021 Water vapor imagery and RAP analysis show a well-defined shortwave lifting ne across e central MN. At the sfc, associated sfc low is over the Twin Cities. The more widespread shra activity has lifted n of Upper MI recently. Hvy downpours have accompanied some of the shra with rainfall rates of around 4 in/hr, though those high rates only lasted for a few minutes given small cells and quick movement. Scattered shra and some isold tsra are now spreading ne into the area ahead of the low pres tracking ne toward western Upper MI. Opted to carry a schc thunder mention into the central fcst area over the next several hrs as a weakening area of elevated mucape shifts ene. Should see some very brief hvy downpours with some of this activity. Temps over the far w high elevations are flirting with the freezing mark. May see some minor ice accumulations on trees. Fortunately, heavier, steadier pcpn has passed. Once the low passes, colder air will switch pcpn to snow over the w late tonight/early Thu morning. A brief period of lake enhanced snow under cyclonic flow/deep moisture will be possible during the morning over the w as 850mb thermal trof with temps down to -12C moves across western Lake Superior. Attm, only an inch or 2 of snow is expected. Last concern for late tonight/Thu morning is the potential of high winds over the s central into especially the eastern fcst area. Sharp caa will drop 850mb temps from around 10C to 0C btwn 09z and 12z, and there will be a favorably oriented pres rise/fall couplet (+2 to +3 mb/3hr and -5 to -7mb/3hr) to the gradient wind to provide isallobaric enhancement. HRRR and RAP have been the most concerning, indicating potential to mix to 50kt winds. There has only been a slight decreasing trend in this potential over the last several hrs of model runs. For now, have increased gusts to the 40-45mph range across the e late tonight/early Thu morning. Will need to monitor upstream trends over the next several hrs to see if the area of gusty winds to around 40kt in IA progresses ne without losing intensity. Right now, those strong winds are occurring just ahead of a 6mb/3hr pres rise. && .SHORT TERM...(This evening through Thursday) Issued at 420 PM EST WED MAR 10 2021 Light to moderate rain spread from SW to NE across the CWA this morning within a robust warm air advection regime. Persistent WAA kept morning minimum temperatures well above freezing with existing snow cover becoming ripe for melting. Fog developed quickly after rain began falling on the ripe snow pack. A negatively tilted shortwave trough over the Northern Plains produced a strengthening 994 mb low near Souix Falls, SD as of 20Z. This low is expected to continue deepening as it approaches and then passes over western Upper Michigan overnight. The expected surface low track is farther west than most of yesterday`s model guidance, which reduced icing concerns for our CWA. The current forecast calls for less than 0.1" of ice accretion except for the Porcupine Mountains and higher elevations of the Keweenaw, which may get up to 0.25" by Thursday morning. The more western low track allowed for more elevated instability to work into the area with a small area of thunderstorms about to cross into MI from WI. This area of thunderstorms appears to be associated with frontogenesis on the nose of the 850 mb low level jet with a broad dry slot apparent immediately to the south. The dry slot should result in several hours of drier conditions for central and eastern zones ahead of the cold front moving through overnight. Visible satellite shows an second area of more surface-based showers developing near the cold front that is draped across Iowa this afternoon. This line of showers is expected to expand as it tracks northeast toward southeastern Upper Michigan. Decided not to include thunder in the grids, but several hundred J/kg of MUCAPE may be enough for a few rumbles of thunder across southern and eastern zones between 03-06Z on Thursday. By 06Z the surface low will be tracking across the U.P. with a secondary cold front bringing substantially colder air into western zones. This air mass appears cold enough to change remaining precipitation to light snow with up to an inch of snow. Winds become southwesterly behind the initial cold front and then westerly behind the secondary cold front. Eastern zones look particularly breezy Thursday afternoon with efficient mixing up to 4-5 kft supporting gusts into the low to mid 30s. .LONG TERM...(Thursday night through Wednesday) Issued at 357 PM EST WED MAR 10 2021 Thursday night will begin with the departing weather system to the northeast and away from the Great Lakes region. Low chances of precipitation may linger in the easternmost areas of the Upper Peninsula Thursday evening as this happens, but impacts look to be marginal at best from the falling precipitation. However, with temperatures hovering near the freezing mark near 0Z Friday that will decrease quickly overnight, there could be some standing water from the recent rainfall we will have received that may cause some slick spots on on roads and sidewalks. Having mentioned the decreasing temps, a quick look at 850mb temperatures shows a drop of approximately 10C overnight. This will be in response to not only partially clearing skies overnight, but an additional shortwave advecting colder temperatures aloft into the region. While the main energy at the surface will stay to the north of Lake Superior for the most part, the surface cold front will cause temperatures to stay chilly for most of the northern half of the Upper Michigan area. This shortwave will quickly move to the east on Friday, but the effects at the surface will respond to 850mb temperatures down to -18C by 18Z with a lingering chance of light snow showers. Most locations will struggle to get out of the middle to upper 20s with the subsidence and CAA occurring. The only areas that will be less impacted with chances of PoPs and elevated surface temperatures are expected to be in Menominee and Dickinson County where weak WAA will still be somewhat present. The progressive shortwave will propagate out of the Great Lakes region by Friday evening toward the New England area, thus limiting the duration of snow showers and flurries to a short time period. From late Friday night into the early portion of next week, there will be split flow jet energy aloft. The polar jet stream will advect multiple shortwaves via nw flow aloft along a building ridge. Saturday looks to be the nicest day of the weekend with the ridge axis building slightly to the east, and over our CWA. Temperatures could very easily reach the middle 40s to lower 50s as sw flow increases in coverage over the area by early Saturday afternoon. As the weak embedded shortwaves ride along the upper level ridge, they will remain close enough to the periphery of the Lake Superior and north Upper Michigan regions to affect our temperatures by Sunday and Monday. This will be a slight change compared to Saturday as daytime highs will be impacted with more cloud cover anticipated, lowering by perhaps 10 degrees across the region. The subtropical jet stream will stay primarily far south of our region as well for the weekend, with an occluded upper level low slowly propagating from the 4 corners region and heading east by Monday of next week. We will need to continue to monitor the medium to extended range guidance as some of the forecast models are showing the northern fringe of this occluded surface low energy making it toward Lower Michigan and southern WI by late Monday of next week. The most likely scenario to play out is that the southern stream of jet energy may amplify the upper level wave and assist with it evolving into a weather system to the south of the Great Lakes region. Tuesday and Wednesday of next week are signaling toward a trend of another upper level ridge building across the central and northern CONUS. This would cause temperatures to increase as warmer air would then be advected into the region. I have increased forecast highs for Tues/Wed of next week up by a few degrees in our southernmost areas in response to this feature showing up in the guidance. If trends continue, this would likely assist with most areas seeing afternoon highs through the middle of next week once again in the low to mid 40s, which would put the area into above average temperatures for mid-March. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 654 PM EST WED MAR 10 2021 Low pres near the Twin Cities will lift ne, crossing western Upper MI during the night. Ahead of the low, -SHRA, BR/FG and LIFR conditions will generally prevail at KIWD/KCMX/KSAW thru the evening. Colder air is currently pushing s into nw Upper MI, and it will probably lead to temps falling to around freezing at KCMX. So, -fzra is expected to develop there during the mid evening hrs. As the low moves across western Upper MI and then out to the ne overnight, pcpn at KIWD/KCMX will switch over to -sn late tonight into early Thu morning. Winds will also become gusty to 25-35kt at all terminals. Prior to that occurring, low-level jet will shift across central Upper MI, resulting in a period of LLWS mid evening until later in the night. KIWD/KCMX will improve to VFR Thu aftn as drier air arrives. Improvement to MVFR will occur late tonight at KSAW, but it may not be until late Thu aftn that conditions improve to VFR. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 420 PM EST WED MAR 10 2021 An area of low pressure tracking northeastward over Lake Superior tonight will lead to periods of gales this evening, overnight, and tomorrow. NE gales are expected on the west half of the lake this evening with a brief period of gusts to 40-45 kts. Upgraded the Gale Watch to a Warning for eastern zones on Thursday afternoon where WNW gales are expected as the low pressure exits to the northeast. Strong winds around 25 kts west half to 30 kts east half are expected again on Friday with another shot of cold air, as well as some patches of heavy freezing spray. However, winds are currently expected to stay below gale force. Winds will then remain around 20-25 kts across the lake through Sunday morning. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Lakeshore Flood Advisory until noon EST Thursday for MIZ014. Lake Superior... Gale Warning from 7 AM to 8 PM EST Thursday for LSZ249>251-266- 267. Gale Warning until 4 AM EST /3 AM CST/ Thursday for LSZ162- 240>244-263-264. Lake Michigan... Gale Warning until 9 AM EST Thursday for LMZ248-250. && $$ UPDATE...Rolfson SHORT TERM...EK LONG TERM...BW AVIATION...Rolfson MARINE...EK