Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/09/23


Area Forecast Discussion
National Weather Service La Crosse WI
955 PM CST Wed Feb 8 2023 .UPDATE.... Issued at 955 PM CST Wed Feb 8 2023 Latest CAMS models and HRRR output continues to show a southeastward shift with the incoming winter storm...and a subsequent shift with the higher QPF and where the more likely location for the heavy snow band will lie. Northeast IA and southwest WI still look favorable for several hours of heavy, wet snow Thursday morning, but the northward extent does not look as far. Have adjusted the Warnings/Advisories to reflect these trends: removed a few counties, adjusted start timing. Also, still feel there is the potential for 6+ within that heavy/Fgen related snow band. However, it could be shifted just south of Grant/Clayton counties...and out of the local forecast area. Will continue to monitor and make adjustments as trends, observational data (obs, radar, satellite) bring the storm in more focus. .DISCUSSION...(This evening through Wednesday) Issued at 243 PM CST Wed Feb 8 2023 Key Messages: - A Winter storm system is still expected to impact the area. There has been a slight shift south and east of the highest snow band, with far southwest Wisconsin and northeast Iowa still expected to see the greatest chance of heavy, wet snow. - The Winter Storm Watch has been upgraded to a warning for Clayton and Grant counties, with the remaining counties in an advisory. - Next chance for precipitation is not until into next week. Plenty of model and ensemble differences that far out in time with just a small chance for precipitation for now. Winter Storm System: Tonight into Thursday The next winter weather system appears to be on track as current GOES-16 satellite imagery shows an upper level low pressure system moving across the Southern Plains. Deepening surface low pressure is expected to track towards southern Lake Michigan by Thursday morning. With this, a surge of Gulf Moisture will be ushered toward southern Wisconsin/eastern Iowa, with 250-300% normal PWATs. Sufficient moisture and upper level support, along with a strong band of 700-600mb frontogenesis, will bring a band of heavy snowfall to portions of the region. As mentioned in the previous discussion, the biggest challenge to the forecast has come with the trend in model guidance moving the band more south and east. However, a bit of run-to-run inconsistency has been noted, especially in the GEFS. While the 06Z GEFS pushed the band of highest snow further south/east, the 12Z ensemble means have again shifted but more slightly north and aligning with its earliest runs. This brings snow probabilities of greater than or equal to 6 inches across parts of far southwest Wisconsin and northeast Iowa. What has brought in a bit more confidence since previous forecasts is the consistency with the latest 12Z HREF ensemble means, which highlights a band of 6+" of 24-hr snowfall from eastern/northeastern Iowa and extending through far southwestern Wisconsin. With model soundings showing much drier air across northern parts of the forecast area, guidance suggests there will be a tight gradient in how far north any precipitation may reach. With this latest guidance and in collaboration with neighboring offices, headline changes to remove La Crosse, Howard, Houston, and Floyd have been made. Further, the watch has been upgraded to a warning for Grant and Clayton counties and an advisory for the remaining counties. The next presented forecast challenge remains in precipitation type during the onset of the storm. Model soundings show a pronounced warm nose suggesting a short period of rain/freezing rain possible, before collapsing and allowing for a change over to mostly snowfall. Clouds have also been slower to move over the area than previous models have suggested. This brings in some uncertainties on surface temperatures, which will affect ptype/impacts. This will need to be monitored through the period, as a glaze of ice could be possible across some portions of northeast Iowa/southwest Wisconsin. Overall, any snow is expected to be more wet and heavy, with highest impacts expected Thursday morning where HREF guidance paints a period of 1+" per hour rates possible. The morning commute will likely be impacted, with reduced visibilities expected with the heaviest snowfall. Another wave is forecast to follow behind, with a chance for lingering snowfall Thursday afternoon as a surface cold front swings through. Monday and Tuesday... After the tonight/Thursday system, the next chance for precipitation looks to be out toward the end of the forecast period. The latest model guidance looks to maybe be a bit slower with the arrival of the system, suggesting that it may hold off long enough that Monday and Monday night could be dry periods. Since it is out at the end of the forecast period, there is quite a bit of uncertainty with the model solutions. The 08.00Z cluster analysis showed three distinct solutions with each cluster dominated by one of the medium range models. The general idea is that an upper level low over the far southern Rockies/northern Mexico will open up into an open wave and lift northeast toward the region with the surface low tracking somewhere from norhtern Missouri/far western Illinois to as far south as the Ohio River Valley. With this delayed timing and variance in the track of the surface low, the overall ensemble probabilities for getting measurable precipitation Tuesday are on the low side, generally under 30 percent. Given the overall differences, a relatively low confidence forecast until model consensus starts to increase. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 955 PM CST Wed Feb 8 2023 CIGS: increase in high/mid level clouds tonight, then questions arise with how soon (if at all) MVFR/IFR clouds roll in. Current track of winter storm suggests any lower cigs moving in from the south would hold just south of the TAF sites. Lower cigs could/would move in from the west, with a secondary shortwave. While the models don`t all agree the lower cigs will reach the TAF sites, for now will lean into the model blend - which does. If low clouds do manifest, exiting of the storm late Thu night would bring west-east clearing for Fri morning. WX/vsby: latest CAMS and HRRR are trending the winter storm a bit more southeast, and even the northward extent of the associated pcpn shield could miss KLSE now. A small chance for light snow in the afternoon with a secondary shortwave - but not enough of a chance/confidence to add to the forecast. WINDS: light vrb tonight, swinging north and increasing toward 12z Thu. The winds will continue to increase and become gusty as the pressure gradient tightens. Speeds aren`t expected to decrease much Thu night. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...Winter Weather Advisory from 3 AM to 6 PM CST Thursday for WIZ054-055. Winter Storm Warning from 3 AM to 6 PM CST Thursday for WIZ061. Winter Weather Advisory from 9 AM to 6 PM CST Thursday for WIZ043-044-053. MN...NONE. IA...Winter Weather Advisory from 3 AM to 6 PM CST Thursday for IAZ011-029. Winter Storm Warning from 3 AM to 6 PM CST Thursday for IAZ030. && $$ UPDATE.......Rieck DISCUSSION...04/Skow/EMS AVIATION.....Rieck
Area Forecast Discussion
National Weather Service Denver/Boulder CO
808 PM MST Wed Feb 8 2023 .UPDATE... Issued at 808 PM MST Wed Feb 8 2023 A mid level circulation is near the WY-CO border near Jackson county and will continue moving SSE overnight. Firt band of jet induced snow has affected the mtns this evening, however, drier air along the I-25 Corridor has only allowed for a few light snow showers. Meanwhile, a cold front has moved into sern WY and will move across the plains. As QG ascent associated with the upper level trough moves southward could see some enhancement of snowfall after midnight across srn portions of the I-25 Corridor with a few inches of snow possible. In the mtns will continue to see periods of snow overnight as well. && .SHORT TERM...(This evening through Thursday) Issued at 113 PM MST Wed Feb 8 2023 The short wave trough over northwestern WY early this afternoon, will continue to drop southward into CO by this evening. There will be a period of weak-moderate QG ascent will will pass across the region at that time A cold front, coupled with low level instability will produce a favorable environment for snow squalls mainly in the mountain areas this evening. RAP analysis from SPC show an increasing threat for squall over southwest WY this afternoon which is projected to move across the mountain areas in the 00-04z period. The greatest threat will be along Highway 40, with the forcing weakening as it moves south. The potential will still exist along the I-70 corridor as well, by 03z. The models still show some potential for snow showers across the plains, likely around or shortly after the passage of the cold front. For Denver, this would be in the 03-07z window. The best chance of snow will be along the Palmer Divide, with up to one inch possible. On Thursday, cold drier and very windy with the strongest sfc pressure gradient over the plains through midday. Models seems to keep the stronger gusts just under high wind criteria so will hold off on wind highlights at this time. With that said, peak wind gusts 45 to 55 mph will be possible so still very windy. High temperatures will struggle to get to 30 across the plains, so be prepared for cold wind chill temperatures in the single digits to the teens. The stronger gusts should start to weaken by mid afternoon. Light snow ongoing in the mountains at least through the morning, but confined to the higher northwest facing slopes. .LONG TERM...(Thursday night through Wednesday) Issued at 113 PM MST Wed Feb 8 2023 We`ll quickly rebound from the cooler weather by Friday as ridging quickly builds into the area. Highs will still be relatively cool across the plains... especially where snowpack still exists, but the urban corridor should see highs back into the 40s. Warmer weather will continue on Saturday, with highs in the 40s to 50s across most of the plains. With upper ridging and dry air aloft, expect mostly sunny skies to complement the warmer temperatures. Slightly cooler weather is expected Sunday as a weak system passes through. There may be just enough moisture/lift around for some scattered snow showers across the higher elevations, but it doesn`t look like any meaningful accumulations are on the agenda. An unsettled pattern returns early next week. The general pattern looks favorable for precipitation across most of the state, though guidance (as usual) has been far from consistent. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 430 PM MST Wed Feb 8 2023 Winds should become NNW in the next hour and continue in that direction this evening. A band of snow may cross the area between 03Z and 06Z with a quick drop to IFR conditions for an hour or so. Any accumulation should be under one half inch. Winds will become more north by 06Z and be gusty with ceilings in the 5000-6000 ft range. Can`t rule out a stray snow shower thru 13z as well. On Thu gusty north winds will be in place thru the aftn with gusts from 35 to 40 mph possible by 18z. Ceilings after 13z should be above 8000 ft. && .BOU WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 5 AM MST Thursday for COZ031-033. && $$ UPDATE...RPK SHORT TERM...Cooper LONG TERM...Hiris AVIATION...RPK
Area Forecast Discussion
National Weather Service Louisville KY
951 PM EST Wed Feb 8 2023 .Forecast Update... Issued at 952 PM EST Wed Feb 8 2023 ...A Very Gusty Thursday Ahead... A strengthening area of surface low pressure is now centered near the OK/KS/MO/AR mutual border, and will continue to strengthen to sub-1000mb status as it lifts NNE to the mid Mississippi River Valley by sunrise. A warm front is currently oriented roughly along the I-64 corridor, and will lift northward through this evening, further solidifying the warm sector over our area tonight. For the most part, the warm sector should stay pretty quiet overnight, but will see sporadic shower activity at times, especially with the low level jet ramping up. Gusts will also begin to ramp up as the LLJ overspreads the region and intensifies, but will also not the low level inversion with that surge of warm advection. The low level jet is really expected to ramp up after 03z, peaking between 06 and 15z, with the surface cold front quickly passing through from around sunrise through mid morning. Given that we will have the peak of the low level jet core (65-75 knots), a broken line of showers forced by the front, and a very impressive dry slot all aligning around the 12-15z time frame continue to be pretty concerned about high end Wind Advisory or even some instances of High Wind Warning criteria. The forced showers along the front don`t look too impressive but it won`t take much to get that high momentum air aloft down to the surface. Will keep the Wind Advisory as is for now, with mention of 45 to 55+ mph winds but will also monitor upstream. Currently seeing 63/55 at BWG with a steady SE wind, and will note that both T/Td values are running a little warmer/more moist than RAP soundings show for the 02z time slot. This is a little concerning with respect to the low level thermodynamic profile, and would be more favorable for deeper mixing/better downward momentum transfer if obs continue to run more unstable than hi-res forecast soundings suggest. The final question with respect to this forecast would be whether to handle any 58 MPH or stronger gusts with a more short-fused High Wind Warning, or with Severe Thunderstorm Warnings given the convective nature of showers around/after sunrise? Doubt we would see any thunder, but it will be a convective process so it is debatable. It would somewhat depend on how the upstream situation evolves, but High Wind Warning could be easier to message and manage than "Severe Showers". Something for consideration if that scenario plays out. && .Short Term (Now through Thursday)... Issued at 345 PM EST Wed Feb 8 2023 Key Messages... * Strong S/SW winds expected with gusts of 45-55+ mph tonight into Thursday * Rain showers tonight into Thursday morning with embedded thunder possible Discussion... Latest surface observations reveal an area of low pressure near the ArkLaTex region with a cold front extending southward into the western Gulf of Mexico and a warm front extending northeastward through western TN and into south central KY. Across western KY and northwest TN, an area of light to moderate rain has developed as warm and moist low-level air is lifted over the warm front. As we head through the afternoon and evening, the system to our southwest will lift northward and deepen as mutual amplification occurs between the sfc low and the mid-level trough. In association with warm FROPA, light to moderate rain showers are expected mainly west of I-65 where the low-level frontal boundary is more well-defined and better moisture advection is expected. Otherwise, mostly cloudy skies are expected with light easterly winds beginning to veer SE and increase in magnitude after midnight. Tonight, the mid-level trough over the southern Plains will become negatively tilted with strengthening height gradient and increasing curvature contributing to the development of a jet core over AR and the MO bootheel. Low-level response in the form of a rapidly intensifying LLJ is expected across western and central KY and southern IN after midnight, with 850 mb jet core of 65-75 kt developing near the I-65 corridor around sunrise tomorrow. Initially, HRRR/NAM soundings show a modest stable layer between 925 and 850 mb which should preclude efficient downward mixing; however, winds should still increase gradually throughout the overnight hours. As the cold front approaches from the west toward sunrise, a line of showers and thunderstorms will approach central KY and southern IN from the west. Instability is expected to remain elevated and very limited along and east of the Natcher Parkway, so while this line of storms may initially bring a variety of severe hazards for areas to our west, the line will likely be decreasing in intensity as it crosses our area, with little more than isolated rumbles of thunder expected. However, this does not mean that severe impacts are not possible with this line of mostly showers and embedded thunder. The aforementioned stable layer aloft is expected to gradually erode overnight, and as showers move into the area, they could facilitate downward momentum transfer of extremely strong winds aloft. HREF 50th percentile wind gusts are generally around 45-55 mph across the region around sunrise through the mid-morning hours. As a result, will continue with the Wind Advisory at this time. While isolated 58+ mph wind gusts are possible (particularly at typically well- mixed ASOS locations like SDF/LEX), think that for most areas, this should be a high-end advisory event. Winds will be of particular concern along W-E oriented roads, as prevailing direction should be southerly during the morning hours. Winds will remain strong through the day on Thursday with the near-sfc pressure gradient gradually relaxing, veering from S to SW during the afternoon and evening hours. Gusts of 35-45 mph will be common through the day, with sustained winds of 20-30 mph expected. Rainfall will not be the main story with this system as expected precipitation totals continue to decrease with this system. Highest rainfall amounts will be across southwestern IN, where 0.5-1" of QPF is possible. Otherwise, the rest of southern IN and central KY is only expected to see between 0.1-0.5", with precipitation mainly coming in association with cold FROPA for areas east of I-65 Thursday morning. Temperatures on Thursday will remain relatively mild despite cold FROPA, although values will gradually decrease from west to east during the afternoon and evening hours. High temperatures will range from the upper 50s and lower 60s in the west to the mid-60s in the Bluegrass and Lake Cumberland regions. .Long Term (Thursday night through Tuesday)... Issued at 315 PM EST Wed Feb 8 2023 The long term weather pattern could be summed up as highly active with low impactful weather over the Ohio Valley during the period. The strong occluded system that will bring strong gusty winds on Thursday will lift off to our northeast Thursday night as a weak area of sfc high builds in over the area. Winds will quickly diminish overnight into Friday with colder air advecting in behind the departing system with a northwest flow and lows into the mid/upper 30s. An upper-level trough stretching from the Upper Midwest into the Mid MS Valley, moves across the Ohio Valley Friday into Friday night. The trend in the latest model guidance has been towards drier weather across our area during this period as the best dynamics and moisture look to remain to our west and south, closest to where a cut-off upper low develops across the Deep South Friday night into Saturday. While moisture is very limited, going to at least mention the chance of a few sprinkles during the day Friday with a few flurries mixed in Friday night. Highs Friday will range from the mid/upper 40s north of the Ohio River with low/mid 50s to the south across central and southern KY with lows falling into the mid/upper 20s by Saturday morning. The aforementioned cut-off upper low will slowly move along the Gulf Coast Saturday into Sunday developing a surface low off the southeastern coast of the US Saturday night. the sfc low along with the upper low will the work northeast along the east coast of the United States. There remains a lack of model agreement in the deterministic on just how far east and north the precipitation shield associated with this system will go. For this forecast, decided to keep the trend of just a slight chance of precipitation across the southeast and eastern part of our CWA Saturday afternoon into the day Sunday with the vast majority of the area remaining dry. Some of the precipitation could feature a wintry mix Saturday night into Sunday. It will be cool on Saturday with highs in the low/mid 40s and lows Sunday morning in the mid/upper 20s. Temperatures will warm back to near 50 for Sunday. Early next week will feature another short wave trough passing through the Great Lakes on Monday with an area of high pressure across the Deep South. Lack of moisture across the region will keep us dry to start the week until the next system comes out out of TX along with another upper low that looks to track into The Ohio Valley Tuesday into Wednesday bringing rain to the area. It also looks to be mild with highs in the mid/upper 50s Monday and Tuesday with near 60 on Wednesday. && .Aviation...(00Z TAF Issuance) Issued at 705 PM EST Wed Feb 8 2023 Impacts: - Strong, gusty S/SW winds and LLWS tonight into Thursday - Occasional reduced ceilings (MVFR levels) - Intermittent rain showers through Thursday morning Discussion: A strong area of low pressure is expected to move across the Ohio Valley tonight into tomorrow morning. Rain showers will be most common at HNB/BWG/SDF early this evening, although vis should stay VFR. Occasional MVFR ceilings may be noted at times, but will prevail more VFR given increasing magnitude of low level winds. Once the warm front passes by, winds will increase overnight, veering from southeasterly to southerly. Low-level wind shear is also expected, especially after 06Z tonight thanks to a 50-60 knot low level jet. Winds should reach a maximum as the cold front passes through around sunrise to mid morning Thursday, with sustained winds of 20-30 kt and gusts of 40+ kt expected. Once the front clears the region, winds will remain strong through the day on Thursday, gradually veering from southerly to southwesterly to westerly by the end of the forecast cycle. Confidence: Medium-High on winds/LLWS, Low-Medium on ceilings, visibilities && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...BJS Short Term........CSG Long Term.........BTN Aviation...BJS
Area Forecast Discussion
National Weather Service Melbourne FL
853 PM EST Wed Feb 8 2023 ...New UPDATE, MARINE, AVIATION, PREV DISCUSSION... .UPDATE... Issued at 850 PM EST Wed Feb 8 2023 Late afternoon model guidance began to hint at the potential for fog development overnight across northern Brevard, southern Volusia, western Seminole and western Orange counties. However, more recent model runs have trended away from the potential for fog, and confidence in fog development remains very low. Prescribed fires from this afternoon may still cause some visibility reductions overnight and into the the early morning, particularly across southern Osceola and northern Okeechobee counties where web cam observations continue to show an active prescribed burn. As of 830 pm, temperatures were mostly in the mid to upper 60s with lower 70s along the Treasure Coast. Low temperatures will fall into the upper 50s inland with low 60s along the coast. && .PREV DISCUSSION... Issued at 334 PM EST Wed Feb 8 2023 Tonight-Thursday...The early morning stratocu deck over the Atlantic waters has retreated some this afternoon as a field of cumulus has developed over land areas. A small hint of the east coast sea breeze has appeared on visible satellite in the erosion of the cu field but remains east of I-95. Pleasant conditions this afternoon will continue through the evening and overnight as the surface high over the Atlantic maintains control of the local weather regime. Lows drop to the upper 50s inland and low 60s at the coast. Tomorrow, the surface ridge axis drops southward slightly, which will veer southeasterly winds to the south ahead of an approaching cold front that will arrive later in the week. Added in a slight chance of showers for the southern interior late Thursday, due to an increase of pre-frontal moisture and hints from the HRRR suggesting precip lifting northward out of south FL. High temps will continue a warming trend, with values well above normal in the low to mid 80s. Friday-Saturday...A mid-level ridge positioned across the trough positioned across the Bahamas will gradually shift further east as a trough located across the Deep South sweeps eastward towards the Florida peninsula. At the surface, an area of low pressure and its associated fronts will begin its approach towards east central Florida Friday. Both the GFS and the Euro have slowed down in their timing, with both models coming into agreement on a Saturday frontal passage across the peninsula. Moisture across the area increases ahead of the front, leading to a potential for isolated showers late Friday. Isolated thunderstorms Friday night into Saturday cannot be ruled out in association with the frontal passage. Have removed the thunder risk on Friday based on the latest timing and guidance, but added a slight chance for storms Friday night and Saturday. Temperatures on Friday will be well above normal, with morning lows in the low to mid 60s and afternoon highs in the mid 80s. Saturday, a temperature gradient across east central Florida will be present, depending on where the cold front is located. In the morning, lows in the upper 50s to low 60s and afternoon highs in the upper 60s to low 70s north of I-4 and in the mid 70s to around 80 southward. Sunday-Wednesday...As the surface low and its associated frontal boundaries lift towards the northeast and away from the area, an area of high pressure will shift from the GOMEX towards the Florida peninsula, keeping conditions relatively dry through Wednesday. Winds out of the west on Sunday behind the front at 10-15 mph will gradually subside as winds veer towards the south by Wednesday at 5 to 10 mph. Temperatures will cool slightly on Sunday, with morning lows in the low 40s to mid 50s and afternoon highs generally in the 60s. Lows Monday morning will drop into the low 40s north of I-4, and in the mid to upper 40s south of I-4, warming up to the upper 60s to low 70s. Tuesday, morning lows in the mid 40s to low 50s and afternoon highs in the mid 70s to low 80s. Wednesday, morning lows in the upper 50s to low 60s, afternoon high in the low to upper 80s. && .MARINE... Issued at 334 PM EST Wed Feb 8 2023 Tonight-Tomorrow...Boating conditions will deteriorate tonight as seas quickly build from 3-5 ft to 5-6 feet south of Cape Canaveral but will return to less than 6 feet by Thu afternoon. Southeast winds near 15 knots will veer southerly late tomorrow as the surface ridge shifts southward. Small craft should exercise caution tonight south of Sebastian Inlet and the offshore waters south of Cape Canaveral. Friday-Monday...An area of surface high pressure will begin shifting further east across the Atlantic, leading to a slight increase in moisture on Friday ahead of a frontal boundary passage on Friday night into Saturday night. Rain chances increase, with a slight chance for thunder across the local waters as the front passes. Southerly winds between 10 to 20 knots will become westerly behind the front, and increase to 15 to 22 knots. Boating conditions will be unfavorable, with seas 3-5 feet across the local waters before and during the frontal passage. Conditions will further deteriorate behind the front as seas increase to 3-5 feet in the nearshore and 5- 8 feet in the offshore waters Sunday into early Monday. Small Craft Advisories may be necessary across the offshore waters during this time period. By Monday afternoon, winds veer towards the north and decrease, with seas gradually subsiding to 2-4 feet in the nearshore and 3-6 feet in the offshore waters. Dry conditions behind the front. && .AVIATION... (00Z TAFS) Issued at 850 PM EST Wed Feb 8 2023 E wind will veer through the period becoming SE around 8-12 kts tomorrow afternoon. Low confidence for fog development at SFB/TIX/DAB overnight. TEMPOs at SFB/TIX/DAB for 5SM VIS before sunrise. Dry conditions prevail. && .PRELIMINARY POINT TEMPS/POPS... DAB 75 60 79 63 / 0 10 0 20 MCO 80 60 83 65 / 0 0 10 20 MLB 76 62 79 65 / 0 0 10 10 VRB 77 63 80 64 / 0 0 10 10 LEE 80 59 83 65 / 0 0 10 20 SFB 79 59 83 64 / 0 0 10 20 ORL 80 61 84 66 / 0 0 10 20 FPR 76 64 80 65 / 0 0 10 10 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ SHORT TERM...Law LONG TERM....Pendergrast AVIATION...Law
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
839 PM CST Wed Feb 8 2023 .UPDATE... Issued at 835 PM CST Wed Feb 8 2023 Main thing of note as we start to get more 00z guidance in is that what were already fleeting snow chances for our CWA on Thursday are pretty much now non-existent. The precip shield with the shortwave pushing north out of Oklahoma now will remain to our east, while the cold front coming in from the trough moving into the western Dakotas looks to lack enough moisture to produce much more than a stray flurry when looking at forecast soundings from the NAM, GFS, and RAP. && .DISCUSSION...(This evening through Wednesday) Issued at 307 PM CST Wed Feb 8 2023 KEY MESSAGES - Warm today, but cooler on Thursday and Friday before temperatures rebound this weekend into early next week. - Chances for snow continue to trend down for Thursday. - Active weather pattern possible the first half of next week bringing numerous chances of rain and/or snow. There is low confidence in the timing and track of these systems. THIS AFTERNOON THROUGH TONIGHT...Currently, temperatures across the region are detailing a small sampler of spring fever this afternoon. Visible satellite imagery depicting relatively clear skies and plentiful sunshine across the state compliments to high pressure overhead. Most areas this afternoon should see near 40 degrees for highs and even mid-40s for some East Central MN counties. Lows tonight will range near 20 degrees due to lack of cloud cover in Western MN. Mid-20s expected for Eastern MN/Western WI where clouds will develop much quicker due to an approaching system southeast of our region. Winds will remain light out of the south which will increase the possibility of patchy fog in some areas. THURSDAY...Thursday morning our region will be saddled in between two different features. To our southeast, strong low-pressure will produce widespread precipitation to Wisconsin`s Southern Coulee Region. Meanwhile to our northwest, a weak shortwave will develop between Manitoba and Ontario which will dive southeastward over our region. Given the strength of the system to our southeast, model guidance and forecast soundings have signaled weaker omega as this shortwave passes. Therefore decided to reduce PoPs region wide and limit to only the "slight" category for parts of the MN River Valley and Southern MN. Aside from precip chances, southerly winds will transition to northerly between 15-20 mph with up to 30mph gusts possible across the region, and near 40 mph in western MN. Highs are expected to reach the mid to low 30s but accounting for the wind will feel more like the lower 20s. THURSDAY NIGHT THROUGH NEXT WEEK...By thursday night into Friday, the aforementioned shortwave clears our forecast region and deep upper level troughing will dig in to the southern plains. Skies will clear from west to east and allow lows to sink down into the upper single digits by Friday morning under mostly sunny skies with highs in the low-20s. Despite the colder temperatures Friday, High pressure returns this weekend and winds will shift back southwesterly on Saturday and highs rebound back in to the mid-30s for highs and lows in the mid-20s. This temperature and quiet weather pattern will continue into early next week. Guidance is continuing to hint at a potential system to impact the Central U.S. by the middle of next week. So far, this system appears to have a lot of moving parts to it. A shortwave over the Baja Peninsula will undergo cyclogenesis across the Rockies and advance eastward. The track of this potential system greatly varies which ultimately modifies what impacts we would see here in MN/WI. The GEFS prefers a more northerly route which would significantly increase chances of receiving significant snowfall in our area, whereas the EPS favors a more southerly track and we see limited to no impacts. With that said, decided to remain with the blended guidance for PoPs in the chance categories until more agreement is made between guidance members. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 541 PM CST Wed Feb 8 2023 What is now clear is that MPX terminals will remain dry this period, with snow expected to remain southeast of our terminals. What is very much less clear is what happens with potential fog tonight as we get squeezed between the system coming out of TX and another moving across the Dakotas. The pluses for getting fog is we`ll see light and variable winds as we sit between the two systems, with ample moisture in the area following today`s snowmelt. The main negative is that even though the TX storm may not bring us precip, it will bring us mid/upper cloud cover. The greatest fog risk resides from RWF to RNH and points in between. Model agreement on fog is greatest at STC/MKT, so this is where we have been most aggressive with dropping vsbys in fog. Thursday, as the western wave moves through, we do anticipate a band of MVFR/IFR cigs to move through as well, for that threat, leaned into the RAP, which has a much shorter window for the stratus than the LAV. Winds will remain fairly light until the western trough moves through, with the CAA behind it helping to promote the potential for 30-40 kts wind gusts in MN. KMSP...Lower confidence in this TAF between about 8z and 16z. The big unknown here is what happens with any fog/stratus development tonight. The HRRR has had a tendency recently to be too aggressive with fog formation, so continued to be cautious with how aggressive to get with fog/stratus mention tonight through Thursday morning. The MVFR cig window you see aligns with when the RAP shows the cold front sweeping through, with its forecast soundings showing a batch of IFR/MVFR stratus coming through immediately behind the front. /OUTLOOK FOR KMSP/ FRI...VFR. Wind NW 5-10kts. SAT...VFR. Wind SW 10-15kts. SUN...Chc IFR cigs. Wind lgt & vrb. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ UPDATE...MPG DISCUSSION...JRB/RMD AVIATION...MPG
Area Forecast Discussion
National Weather Service Paducah KY
532 PM CST Wed Feb 8 2023 .UPDATE... Issued at 530 PM CST Wed Feb 8 2023 Updated the aviation section for the 00Z TAF issuance. && .SHORT TERM...(Tonight through Thursday night) Issued at 227 PM CST Wed Feb 8 2023 Overview...A dynamic system will impact the region over the next 24 hours with a multitude of impacts ranging from flooding to very strong wind gusts and even a lower end severe storm potential. Flooding...The 12z hi-res models trended wetter with QPF across southeast MO and especially southern IL. Particularly concerning were the HRRR and ARW which were leaned on to generate the WPC rainfall totals. Thus, have extended the Flood Watch to encompass all of southern Illinois. Likely will be a swath of 2-3" develop across part of this area. Even more concerning is the potential for 3- 4" totals across pockets of southeast MO, with the Ozark Foothills most favored. Quick rises on area creeks/streams will likely occur and will need to be especially mindful of low water crossings through tonight. There likely will be a sharp southeast cutoff to the higher end rainfall amounts with somewhere near the Ohio River being the transition area. Most of the KY Pennyrile region likely wont even receive a half inch. The rain quickly exits the region late tonight with the entire region likely dry by 12z. Winds...A period of very strong gradient winds are expected to develop after midnight and continue into the early afternoon on Thursday. A sting jet-like feature will develop across the region in response to a rapidly deepening surface low (10 hour pressure falls of 12-15mb) that moves from southeast Missouri into northern Illinois. 850-925mb winds within the low level jet are modeled to increase into the 50-75 kt range. BUFKIT sounds also suggest our inversion disappears overnight, which lends to higher confidence in momentum transfer of some of the higher winds aloft down to the surface. Still not overly confident we will see widespread winds strong enough for a High Wind Warning. However, with soggy ground the overall impacts may not be that different. In collaboration with neighboring offices, will continue with a higher end Wind Advisory for wind gusts of 45-50 mph and just enhance the wording a bit to stress this isn`t your typical Wind Advisory. The heavier convective elements may bring down some gusts greater than 50 mph. However, the strongest gusts may occur just beyond the departure of the rain. HREF mean wind gusts show highest likelihood of greater than 50 mph across the KY Pennyrile and southwest Indiana so this may be the area most likely to observe the higher end gradient winds. Winds will gradually decrease late morning into the afternoon tomorrow and we may be able to cancel the advisory early across the west half of the region. Severe...The severe thunderstorm threat continues to be somewhat iffy with this event. Overall not much change from previous forecasts though. Given the impressive low level wind fields that develop tonight and the fact the inversion disappears on forecast soundings, there may be a heightened risk for a few of the heavier showers or storms to bring down some of the higher wind just off the deck. Whether this is 45-50 mph or 60+ mph gusts is the question though. Instability is meager, but sufficient enough to generate some lightning. HREF guidance suggest the best chance at any sfc CAPE developing would be between 03-08z across the MO bootheel into the Jackson Purchase area of west KY. A non-zero threat for a brief tornado exists in this area. Otherwise, the primary threat will be damaging winds. Primary timing for severe potential is between 03- 10z. .LONG TERM...(Friday through Wednesday) Issued at 227 PM CST Wed Feb 8 2023 A positively tilted shortwave trough will pass through on Friday. GFS/ECMWF/NAM still generate a little QPF in an area of jet-level ascent and frontogenetic forcing. Surface temperatures should be relatively warm although there will be ample cold air aloft under the trough so snow may mix in a little sooner than surface temps suggest. Nevertheless, QPFs are 0.1 to 0.2" and probably 75% of that will fall as rain. Still a small chance for some glaze or very light snow accumulation Saturday morning but nothing measurable, and for now impacts appear minimal. Temperatures will be chilly Saturday in strong cold advection behind the storm system, north to northwest winds at 10-15 mph will bite amid low 40s air temperatures. There should be a decent bit of sun coverage however, particularly late in the afternoon that will keep temps from bottoming out too much. The northerly winds should ease up on Sunday perhaps switching more southerly by afternoon as upper level ridging works overhead. Temperatures should moderate quite a bit with maxes around 50. Winds shift more southwesterly on Monday increasing low level moisture a bit and temperatures another 5-6 degrees. The next storm system begins to approach Tuesday. Rain and unsettled weather look like a safe bet once again Tuesday afternoon through Wednesday. The 12z GFS/ECMWF are in good agreement with the synoptic details but there isn`t much run to run continuity established with the details. Right now it looks like a somewhat similar pattern to todays weathermaker, only displaced southeast about 150 miles. We barely clip into the warm sector in the deterministic runs but still get into fairly high precip totals, around an 1-1.5 inches. Looks like an overall lower flood/severe threat right now than what we are dealing with today as well, but those details of course could change as we get closer. && .AVIATION... Issued at 530 PM CST Wed Feb 8 2023 Rain continues to move through the Quad State this evening. A thunderstorm or two is possible, perhaps more likely late this evening at southern sites as a potential line of showers/storms develops. Winds will increase this evening and overnight, continuing into tomorrow, with wind gusts to 35-40 kts at the peak. Winds shift from northeasterly ahead of the gusty winds, to southerly and then southwesterly with the stronger gusts. LLWS is more likely this evening than later as winds aloft may become strong before surface winds. Vsby drops are likely with heavier showers and storms. Cigs are MVFR to VFR to the southeast and IFR to LIFR in the northwest, and will generally stay near current ranges through the evening before increasing slowly overnight and tomorrow. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Flood Watch through late tonight for ILZ075>078-080>094. Wind Advisory from midnight tonight to 3 PM CST Thursday for ILZ075>078-080>094. MO...Flood Watch through late tonight for MOZ076-086-087-100-107>112- 114. Wind Advisory from midnight tonight to 3 PM CST Thursday for MOZ076-086-087-100-107>112-114. IN...Wind Advisory from midnight tonight to 3 PM CST Thursday for INZ081-082-085>088. KY...Wind Advisory from midnight tonight to 3 PM CST Thursday for KYZ001>022. && $$ UPDATE...ATL SHORT TERM...SP LONG TERM...JGG AVIATION...ATL