Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/05/20

Area Forecast Discussion
National Weather Service Green Bay WI
528 PM CST Tue Feb 4 2020 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Wednesday Issued at 244 PM CST Tue Feb 4 2020 The latest RAP analysis and satellite/radar imagery show arctic high pressure centered over the northern Plains and a stalled front over the Ohio Valley. A period of clearing has moved over northern WI as lake effect clouds retreated closer to Lake Superior and mid/high clouds moved east of Wisconsin. Meanwhile, more mid and high clouds are moving northeast over the central Plains. With a cold and dry airmass that is more typical of winter in place across the region, forecast concerns continue to revolve around clouds and temps. Tonight...The arctic high pressure will become centered across the region. Normally this would be conducive for tanking temps, but guidance insists on periods of mid and high clouds overhead. The clouds will likely be more widespread and thicker over southern parts of the region, while clouds should be thinner over the north. As a result, temps should be substantially colder across the north (where deeper snow pack exists). Used a blend of the statistical guidance and the previous forecast as a starting point, then made a few minor adjustments to tweak temps up where more clouds should be present. This put lows ranging from near 10 below over the northwoods to the middle teens near Lake Michigan. Wednesday...High pressure will remain centered across the region. Mid and high clouds should exit for a time during the morning before they return in the afternoon ahead of the developing cyclone over the southern Plains. Perhaps tweaked temps up a tad from the previous forecast, but still mainly in the middle 20s. .LONG TERM...Wednesday Night Through Tuesday Issued at 244 PM CST Tue Feb 4 2020 The main highlights for the extended forecast are the various chances for light snow and temperatures remaining near or above normal. Wednesday night through Thursday...An upper-level trough positioned over the central U.S. will help a surface low pressure system move northeast over the central Appalachia region Thursday morning. Although models have been somewhat consistent with the northwest portion of this system bringing light snow to portions of southeastern Wisconsin, they are not all in agreement with how far north to bring the snow. Continued the light snow accumulations up to 2 inches in east-central Wisconsin by Thursday evening, with locally higher amounts in Manitowoc County. As the main upper-level trough moves over Wisconsin Thursday evening and the low pressure system pushes further east, it is possible for some lake enhanced snow to develop over Manitowoc and Kewaunee County Thursday night. Friday through Saturday...The upper-level pattern will transition to a northwest flow over the Upper Mississippi Valley by Friday morning. An weak embedded shortwave riding the northwest flow looks to move over the region sometime between Friday morning and Saturday. Any snow associated with this shortwave would be light, with the best chances across northern Wisconsin. Rest of the extended...By early Sunday morning, the upper-level pattern will transition to a zonal flow stretching across the entire CONUS, with a 125+ knot jet and a mid-level shortwave moving into the Upper Mississippi Valley. Model guidance appears to be in decent agreement with this system bringing accumulating snow to the region. Although some uncertainty remains with the timing and exact location of highest precipitation, confidence is high enough to increase PoPs to likely for Sunday afternoon. An area of high pressure will then move in behind this system for Monday, which may allow for some peeks of sunshine. && .AVIATION...for 00Z TAF Issuance Issued at 528 PM CST Tue Feb 4 2020 High pressure is forecast to build into Wisconsin tonight and slide to our east on Wednesday. Still expect to see mid and high clouds spread across the area over the next 24 hours as a system organizes over the southern Plains and taps gulf moisture. Light and variable winds expected for tonight, then become southwest at 5 to 10 knots on Wednesday. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......Hykin AVIATION.......AK
Area Forecast Discussion
National Weather Service Wichita KS
939 PM CST Tue Feb 4 2020 .UPDATE... Issued at 933 PM CST Tue Feb 4 2020 Thinking essentially remains unchanged regarding accumulating snow late tonight through Wednesday. Latest model data, including the HREF, continues to indicate 1-4" (locally 5") mainly east of the KS Turnpike. Highest amounts should be extreme southeast KS (e.g. Labette, Cherokee, Crawford), where amounts closer to 4-6" are possible. Thinking locations generally west/northwest of KS Turnpike will see one-half inch at best, including Wichita metro. Central KS should see little if any snow. && .SHORT TERM...(This evening through Friday night) Issued at 400 PM CST Tue Feb 4 2020 Late this afternoon and early evening, most light snow/freezing drizzle has ended up in central Kansas, though a brief flurry or light patchy drizzle cannot be ruled out over the next few hours. However, any lingering precipitation would be very light, and few impacts are to be expected from this activity. The winter weather advisory has thus been adjusted accordingly. After a break in precipitation this evening, things should start to ramp back up for mainly southeast Kansas but portions of south central Kansas as well by late tonight and tomorrow morning. During the day tomorrow in far southeast Kansas, an impressive axis of mid-level frontogenesis and lift will coincide with a southern stream shortwave that will move across central and eastern Oklahoma and into the Missouri/Arkansas region during the day. An analysis of RAP model forecast soundings from the Labette/Neosho County area shows a very deep, saturated profile extending well into the ice producing layer aloft and a lack of a warm nose that exceeds the freezing mark. As a result, precipitation should be all snow. Given potential mesoscale processes and a narrow band of impressive lift, it is not out of the question for an axis of much higher snowfall amounts somewhere in the vicinity of where the the Kansas/Oklahoma/Missouri/Arkansas borders meet. Though there is still some uncertainty on where the heaviest accumulations will exactly land, felt, in collaboration with surrounding WFOs, that a Winter Storm Warning was justified to account for this potential, especially in the Montgomery, Neosho, and Labette area. Another question that remains is how much snowfall will be received in areas further to the west in south central Kansas. In general, snowfall amounts should taper off the further west you go, with a trace to two inches likely along the Kansas Turnpike corridor into the Wichita metro and then slightly higher 1-3 inches roughly between the Eureka and Chanute corridors. A few models (including HREF data) show a second lighter axis of snowfall just west of the main one in far southeast Kansas, so felt keeping the Winter Weather Advisory in tact as far west as Harper County was justified at this time, though it is possible that later shifts will need to make slight adjustments based on trends. After this system moves off Wednesday night, drier air and a slow but steady warm-up will ensue in the next few days. The main mid/upper trough will translate east of the forecast area by late Thursday, and do think that at least some cloud cover and northerly flow will limit temperatures to the 30s and 40s for Thursday (with the coldest areas being in southeast Kansas corresponding to fresh snowfall). Temperatures should be slightly warmer on Friday, though once again cloud cover may be the limiting factor to prevent them from reaching higher than the mid 40s or so. .LONG TERM...(Saturday through Tuesday) Issued at 400 PM CST Tue Feb 4 2020 Few changes were made to the long term forecast. A surface ridge will slide across the forecast area this weekend keeping the weather dry as temperatures gradually increase into the upper 40s or low 50s. Early indications are that some light rain or a wintry mix may be possible in southeast Kansas early next workweek. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 550 PM CST Tue Feb 4 2020 MVFR ceilings will persist overnight across the region. Cannot rule out patchy areas of light snow or flurries overnight, but accumulations will be little if any. Better chances for accumulating snow and associated IFR conditions arrive from the southwest late tonight through Wednesday, especially along and southeast of the KS Turnpike corridor. Wichita should be on the far western edge of this snow. && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 24 32 18 39 / 40 40 10 0 Hutchinson 21 31 17 40 / 20 20 0 0 Newton 22 30 17 38 / 30 40 10 0 ElDorado 24 31 17 37 / 60 70 20 0 Winfield-KWLD 25 32 17 38 / 70 70 30 0 Russell 19 32 14 41 / 20 10 0 0 Great Bend 18 33 14 43 / 20 10 0 0 Salina 22 31 16 40 / 20 10 0 0 McPherson 21 30 16 38 / 20 20 0 0 Coffeyville 28 32 16 35 / 70 90 50 0 Chanute 27 31 16 33 / 70 90 40 0 Iola 26 30 16 33 / 60 90 40 10 Parsons-KPPF 28 32 16 34 / 70 90 40 0 && .ICT WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until midnight CST Wednesday night for KSZ052-053-068>072-083-091>095-098. Winter Weather Advisory until 6 AM CST Wednesday for KSZ096-099- 100. Winter Storm Warning from 6 AM Wednesday to midnight CST Wednesday night for KSZ096-099-100. && $$ UPDATE...ADK SHORT TERM...TAV LONG TERM...TAV AVIATION...ADK
Area Forecast Discussion
National Weather Service Jackson MS
543 PM CST Tue Feb 4 2020 .UPDATE... Updated for 00Z aviation discussion && .AVIATION... 00Z TAF discussion: Some light rain showers will move through parts of the region this evening. SHRA/TSRA may occurr at GLH/GWO after 02-06Z. Overall, flight categories will drop to IFR/LIFR ceilings tonight with potential for a slight improvement before additional storms tomorrow afternoon through the evening hours. Flying conditions not expected to be good for the next 18-24 hours. && .DISCUSSION... Tonight & Wednesday: Overall an active weather maker is on tap for the next 24 hours as a strong cold front moves into the region. Severe weather & flash flooding potential will be on the increase ahead of this strong cold front through Wednesday. Tonight: As a strong trough digs over the lee side of the Rockies & into the southern Plains & Texas Panhandle tonight, expect a lead shortwave jet to lift out to the east-northeast into the Appalachians. In addition, the stronger spoke of energy will be diving far to the south, while another area of forcing will be swinging to the east across southern Canada. Lastly, the strong mid- level ridge will be centered over the southwestern Atlantic & Caribbean Islands, leading to continued southwesterly return flow of moisture into the region. This -PNA blocking pattern will lead to a gradual slowing of the eastward progression of the trough & attendant cold front. In addition, the juxtaposition of severe weather parameters (i.e. bulk shear & limited lapse rates/instability) & southwest-northeast parallel orientation of the cold front, looks to limit severe weather potential. This will lead to a slowdown of any storms ArkLaMiss Delta. Due to very limited forcing & severe potential, decided to remove the "Marginal" severe threat for the overnight hours. Can`t rule out an isolated strong- severe storm or so across the Delta, but coverage looks limited enough to not mention in the HWO/graphics. Wednesday: As the mid-level ridge breaks down over the southwestern Atlantic & Caribbean Islands, the synoptic pattern will quickly amplify & eject to the east-northeast. This will lead to strong surface cyclogenesis along the baroclinic zone from the western Gulf of Mexico up through ArkLaTex, ArkLaMiss Delta & Mid-South. This will continue to provide feedback into the synoptic mid-upper level jet & will intensify to nearly 90-130kts @ 500mb & 300mb, respectively. With strong surface cyclone rapidly deepening from around 1005mb to nearly 1000mb across the ArkLaMiss Delta by mid- afternoon, strong reflection low-level wind fields response will occur. In addition, juxtaposition of increasing mid-level lapse rates & strong mid-deep layer shear (i.e. 6.5 deg C/km lapse rates @ 700-500mb & 40-65kts effective bulk shear @ 0-3km & 0-6km, respectively) will lead to very favorable severe weather environment. Some global consensus shows some potential for some coastal convection, but there remains a good feed of low-level Theta E across central to southwest Mississippi & northeast Louisiana to serve as an impetus for severe weather development along the Mississippi River around noon & to spread east-northeast through the afternoon to evening. Some hi-res guidance indicates even more concerning juxtaposition of parameters, with some experimental HRRR runs showing significant tornado parameter (STP) approaching 6+, bullseye over southwest Mississippi & northeast Louisiana & central portions of ArkLaMiss on the northern gradient & strong updraft helicity swaths. This environment will be very anomalously destabilized (i.e. 1000-1500+ MLCAPE) & sheared. Strong clockwise curving hodographs will lead to supercell & tornado potential, with some increasing potential for even more significant severe weather & upgrade in future outlooks possible. For now, in conjunction with SPC, expanded the "Slight" risk area for severe weather further northwest across the Delta, with "Marginal" risk area across the far northwest Delta. All modes of severe weather are possible, including damaging winds of 60-70mph, large hail of quarter to golf ball size & tornadoes. Keep a close eye on future outlooks for any increase in severe weather potential & upgrades in the HWO/graphics. In addition, there will be flash flooding potential as well as some areas in synoptic jet structure will be diffluent over the baroclinic zone. This will lead to some heavy rain potential near the developing surface low. Further to the southeast, there will remain convective potential in conjunction with anomalous deep layer moisture & very wet antecedent conditions that haven`t completely dried out. Due to that, rainfall of 1-3 inches, with locally higher amounts, is possible across the region. Local hi-res CAM guidance & HREF suite supports this idea. Due to more mesoscale than synoptic driven details, will hold off on any Flash Flood Watch for now. In coordination with the Weather Prediction Center (WPC), expanded the "Limited" risk area for flash flooding for the entire region Wednesday & into Wednesday night. Lastly, due to a strong developing pressure gradient some gusts upward of 25-30mph can`t be ruled out. Expect these winds to really ramp up into the afternoon as the surface low rapidly deepens & moves through the Delta. For now, winds shouldn`t be high enough for a Wind Advisory but will keep an eye on this. /DC/ Wednesday night through next Tuesday: Overall, a wet and potentially stormy pattern can be expected on average during the long range portion of the forecast as a -PNA pattern featuring a western CONUS trough and eastern CONUS ridge re-establishes itself. Initially, the threat for severe storms and heavier rain will shift east of the area later Wednesday night as the cold front pushes through the forecast area. With the shortwave trough lagging well behind the surface front, expect chances for additional light rainfall to continue through Thursday into Thursday evening as cold advection continues. Thereafter, a brief period of dry weather and seasonable temperatures can be expected as we go through Friday into Friday night. But a quick-moving shortwave trough will move in with a chance for showers returning Saturday. Another brief period of dry weather will take place Sunday before unsettled weather returns to start next week. A more significant trough could approach for the middle of next week and this will need to be monitored for more impactful weather. /EC/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 64 73 47 50 / 53 97 90 64 Meridian 63 74 53 55 / 45 95 97 77 Vicksburg 64 72 46 48 / 60 98 73 49 Hattiesburg 63 74 54 56 / 39 98 95 78 Natchez 65 72 45 48 / 50 98 70 51 Greenville 56 62 43 44 / 80 96 66 48 Greenwood 61 68 45 47 / 82 98 85 62 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ 28
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Wednesday) Issued at 311 PM CST Tue Feb 4 2020 An upper level trough extended from the central high Plains southwest across AZ. Minor mid-level perturbations embedded within the southwesterly mid level flow east of the trough axis has provided enough ascent for slight snow, snow grains and sleet to develop across the southwest and southern counties of the CWA. There was also weak isentropic upglide at the 285 K level. At 115 PM an area of light snow has been expanding across Dickinson, Geary and Morris counties. This area of light snow will continue to push east-northeast and may accumulate up to a half inch across the south central counties and along the I-70 corridor late this afternoon into the early evening hours. The light snow and snow grins will be on and off through most of the night but only expect very light accumulations. As the main H5 trough shifts east across the central and southern plains, A more intense PV anomaly will shift northeast cross central OK into southeast KS. Mid level frontogenesis will increase ahead of the PV anomaly across east central KS through the day. The colder temperatures will cause a higher liquid to snow ratio of around 16:1. At this time the heavier snowfall will remain south and southeast of the CWA, with 4 to 6 inches possible across northeast OK, southeast KS into southwest MO. Light snow will expand north-northeast across east central KS after 12Z WED and continue through the afternoon hours of Wednesday before shifting east of the area Wednesday evening. Total snowfall amounts will be up to 1 inch along the KS turnpike, with 2 to 3 inches of snowfall possible southeast of I-35 across Coffey and Anderson Counties by Wednesday evening. I`m leaning more towards the HREF and WRF solutions for this forecast. There will be a tight gradient on the northwest edge of the light snow band. Northeast and north central KS will remain dry, if the PV anomaly tracks a bit farther to the east, then the northern and western portions of east central KS may remain dry and the HRRR model solution is hinting at this potential. Since there is snow already falling across central KS and moving into east central KS later this afternoon, I will keep the winter weather advisory going through the evening hours. After midnight the winter weather advisory will be continued from Morris to Jefferson counties and points southeast for the next round of light snow on Wednesday. Highs on Wednesday will only reach the upper 20s to around 30 degrees. .LONG TERM...(Wednesday night through Tuesday) Issued at 311 PM CST Tue Feb 4 2020 Wednesday night, the light snow will be ending during the evening hours from west to east across east central KS as the upper trough shifts east into MO and the PV anomaly moves northeast into western IL. Lows will drop into the mid to upper teens. Thursday through Saturday, the plains will be under northwest flow at mid-levels. A few weak perturbations embedded in the northwest flow may provide some snow flurries Friday into Friday night. Highs Thursday will only reach the mid to upper 30s with slightly warmer temperatures on Friday and Saturday with highs in the upper 30s to lower 40s. Saturday night through Sunday, an upper level trough will move onshore across the Pacific northwest and dig southward into southern CA. Highs Sunday will reach the mid to upper 40s. Sunday night through Tuesday, a norther stream H5 trough will move east across the northern plains and stronger low-level CAA will cause a cold front to move southward across the CWA. As the upper trough across southern CA shifts east across the southwestern US into the Plains on Tuesday. A wintry mix of precip will develop late Sunday night as isentropic lift develops ahead of the H5 trough as the H5 trough tracks into the plains. The stronger ascent will cause more widespread precipitation to develop Monday night into Tuesday. There is the potential for heavier snowfall across western and northern KS with a freezing rain and snow mix, changing to rain across east central KS Monday night into Tuesday. HIghs Monday and Tuesday will be in the mid 30s to lower 40s. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 531 PM CST Tue Feb 4 2020 Gusty northeast winds continue into the overnight period before gusts subside. CIGS should drop a category into MVFR after 06Z at Topeka terminals and a few hours later around KMHK. A batch of light snow is then expected to overspread terminals around 12Z Wed, so lower visibilities are also expected at that time. Current thinking is that snow will taper off a few hours later but stratus will stick around for most of this TAF period. && .TOP WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until midnight CST Wednesday night for KSZ026-037>040-054>056-058-059. Winter Weather Advisory until midnight CST tonight for KSZ022>024-035-036. && $$ SHORT TERM...Gargan LONG TERM...Gargan AVIATION...Teefey
Area Forecast Discussion
National Weather Service Tulsa OK
550 PM CST Tue Feb 4 2020 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. IFR to MVFR ceilings will continue through the period across the CWA. Winter weather chances increase overnight for Eastern Oklahoma with rain chances for Northwest Arkansas. During the morning hours...snow and sleet becoming all snow are expected for Northeast Oklahoma with a rain/wintry mix elsewhere. Toward the end of the TAF period...snow should be common for most locations with light rain remaining for the KFSM area. Within the snow/sleet...periods of LIFR/IFR conditions with heavier bands of precip will be possible. && .PREV DISCUSSION... /Issued 503 PM CST Tue Feb 4 2020/ UPDATE... A quick update was made to the grids for this evening, inserting the potential for a light wintry mix across northeast Oklahoma. See discussion below. DISCUSSION... A lead impulse is ejecting northeast across the Panhandles and will lift up into Kansas this evening, ahead of the main positive tilt upper trough to the west. Lift with this feature is producing some light precip across western OK. There have been reports of light snow in NW OK with this activity north of the freezing line. The latest HRRR guidance suggests that some of this light precip will spread across northeast OK this evening. If this does occur, precip amounts will be pretty light and shouldn`t cause issues. The main show will arrive after midnight and more toward Wednesday morning. Lacy PREV DISCUSSION... /Issued 322 PM CST Tue Feb 4 2020/ DISCUSSION... Main forecast concerns continue to revolve around the impending winter storm set to impact the region late tonight and into tomorrow. The Winter Storm Warning that was issued earlier this morning will be left unchanged, with the previous Winter Storm Watch now converted to a Winter Weather Advisory. Rain showers continue across the far eastern fringes of the forecast area this afternoon, resulting from an upper level disturbance moving through western Arkansas at present. Once this moves out, there will be a break in the accumulating precipitation, although there should continue to be a few areas of drizzle or freezing drizzle this evening. The main show should begin to move into eastern Oklahoma from the southwest after midnight and likely after 3 am. For areas roughly along the I-44 corridor, the low and mid level temperature structure should support a wintry mix, with portions of northeast Oklahoma to the north and northwest of the Tulsa metro the only areas being cold enough to support all snow at the onset. This will change through the day as the cold air deepens, with all snow likely by midday for most of northeast and a portion of east central Oklahoma. The highest snow/sleet totals still look to occur along the I-44 corridor, where embedded convective elements and resultant enhanced upward motion may lead to locally higher snow/sleet rates. These higher rates currently appear most likely beginning during the latter part of the morning commute in the Tulsa metro area. Some concern exists that the period of sleet will last longer than currently forecast, leading to lower overall snow/sleet totals so this will have to be watched closely. Another area of concern includes portions of southeast Oklahoma into far northwest Arkansas. Depending on surface temperatures, ice accumulation could become a bigger problem than currently forecast, especially in the higher terrain areas of northwest Arkansas. Current accumulations are a tenth of an inch or less in much of this part of the forecast area, with isolated from one to two tenths, but if surface temperatures are just a couple of degrees colder than forecast, accumulations could be higher for areas from McAlester northeastward into northwest Arkansas. A lull in the activity is expected during the afternoon before another band of lighter snow associated with the main upper level trough affects mainly northeast Oklahoma. Additional accumulations of an inch or maybe two could occur through tomorrow evening before the entire system makes a quick exit. Warmer and drier weather will be on the way for the latter part of the week, although the expectation of snow/sleet cover across a large part of northeast Oklahoma should keep temperatures low, especially at night, for the next couple of days. Another storm system for the beginning of next week could bring thunderstorms to portions of the area, with colder air to follow toward mid week. && .PRELIMINARY POINT TEMPS/POPS... TUL 29 32 17 38 / 60 100 50 0 FSM 39 40 26 38 / 30 100 40 0 MLC 32 34 20 40 / 60 100 20 0 BVO 27 32 16 37 / 60 100 50 0 FYV 35 37 24 35 / 30 100 60 0 BYV 34 35 24 34 / 20 100 70 0 MKO 31 33 20 36 / 60 100 40 0 MIO 30 32 16 34 / 50 100 80 0 F10 29 31 17 38 / 70 100 30 0 HHW 36 39 26 40 / 50 100 20 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...Winter Weather Advisory from 3 AM Wednesday to midnight CST Wednesday night for OKZ049-068>075. Winter Storm Warning from 3 AM Wednesday to midnight CST Wednesday night for OKZ054>067. AR...Winter Weather Advisory from 3 AM Wednesday to midnight CST Wednesday night for ARZ001-002-010-011. && $$ AVIATION.....20