Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/16/24


Area Forecast Discussion
National Weather Service Cheyenne WY
804 PM MDT Mon Apr 15 2024 .UPDATE... Issued at 757 PM MDT Mon Apr 15 2024 A few rounds of updates ongoing this evening after a pretty busy afternoon and early evening. Decided to cancel the Severe Thunderstorm Watch early as all the activity has been north and east of Dawes County during this event. Do not expect any additional strong thunderstorms across the western Nebraska Panhandle, but expect quite a bit of lightning close by as another round of severe thunderstorms push north across west central Nebraska overnight. Also made several rounds of temperatures, dewpoint/humidity, and wind updates this evening to account for the rapidly changing conditions associated with surface cyclogenesis across the high plains. This surface storm has produce wind gusts of 55 to 70 MPH already. After a brief lull, these winds should redevelop later tonight and continue through Tuesday. && .KEY MESSAGES... - Critical fire weather conditions across the southern Nebraska Panhandle today where Red Flag Warnings are in effect from noon to 7 PM for gusty winds and low humidity. - A strong storm system arriving today will bring the potential for high winds, showers and thunderstorms (could be strong to severe in the northern NE panhandle), and mountain snow this afternoon through Tuesday. - Strong cold front associated with a large system across central Canada will bring much colder temperatures and the chance for valley snows Wednesday into Friday. && .SHORT TERM /THROUGH TUESDAY NIGHT/... Issued at 300 PM MDT Mon Apr 15 2024 Very active weather over the next 24 to 36 hours as a slowly moving low pressure system moves slowly through northern Colorado into central Nebraska. Currently...992mb surface low analyzed just south of the southern Nebraska Panhandle near the Nebraska/Colorado state line. Cold front extends south southwest into northern New Mexico. A stationary front north of the low through Kimball to Mitchell Nebraska to another surface low near Upton. Ahead of this low...a dryline analyzed from the low southeastward into western Kansas. Current SPC mesoanalysis showing SBCAPE around 1000 to 1500 J/KG. Coordinating with SPC...may see a Watch coming out soon. Am a little troubled with surface dewpoints out in the Panhandle only being in the upper 30s to low 40s. May not see a whole lot of convection out there. Simulated HRRR and RAP radar not showing a whole lot of convection out there through the afternoon. More concern with strong winds tonight into Tuesday on the back side of the surface and 700mb low. GFS has the 700mb low tracking into south central Nebraska near the Kansas stateline. GFS showing 750/800mb winds turning northwest to north and increasing after 00Z. By 03Z...looking at 45-50kts over the south Laramie Range near the I-80 Summit. Winds become stronger and more widespread after 06Z to cover the entire Laramie Range out into extreme southeast Wyoming. Did upgrade remaining watches to warnings for the southern Panhandle and Converse County. By far...our strongest winds look to occur after 12Z Tuesday as 700mb winds up near 65-70kts over the Summit and widespread 800mb winds of 50-55kts. This looks to be our best timing on strong winds for our high wind warnings. Even see 800mb winds of 55-60kts over Kimball and Cheyenne Counties with 750mb winds near 70kts from 15Z through 21Z. Winds easing afterwards. Finally...the wrap around moisture north and northwest of the low. Looks confined mainly across Carbon County this evening before it eventually starts moving eastward as the parent low tracks into eastern Nebraska Tuesday afternoon. This is a warm system with snow levels forecast to mainly above 8000 feet. Mountains look to get pretty good accumulations of heavy wet snow...while lower elevations may stay liquid the entire time. Winter headlines remain in effect for the Sierra Madre...Snowy and south Laramie Ranges. Precip ends from west to east through the afternoon Tuesday with all locations looking dry by 00Z Wednesday. Next frontal boundary approaches from the north and northwest Wednesday afternoon with precipitation developing out west. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 300 PM MDT Mon Apr 15 2024 Wednesday night/Thursday...Looks like an active period for fairly widespread snow as our forecast area will be under a strong west to east jet aloft, along with a slowly sinking Canadian origin cold front and cyclonic flow aloft helping to produce snowfall in a moist airmass. The greatest chances for snow will be Wednesday night, with slowly decreasing coverage after daybreak on Thursday as the colder airmass deepens. Based on projected 700 mb temperatures near -9 Celsius and thick cloud cover, maximum temperatures will be mainly in the 40s, though possibly cooler with the strength of the cold airmass. Friday...Another cold day on tap with another shortwave trough aloft moving through the westerly flow aloft, helping to increase coverage of mainly snow, with greatest coverage from Laramie to Cheyenne to Sidney. Saturday...Another shortwave trough aloft moves across the counties, producing a chance for more snow in the cold airmass near the surface, and banked up into Albany County. More milder temperatures anticipated across Carbon County and Rawlins where the colder air will be less deep. Sunday...Expect a decent warming trend as westerly flow aloft helps develop a surface lee trough, which allows the cold airmass to retreat to our east. With 700 mb temperatures near 6 Celsius, maximum temperatures will be in the mid 50s to lower 60s. Monday...The mild temperatures continue in advance of the next approaching cold front under zonal flow aloft. Could see the possibility of another cold front bringing colder temperatures again, though confidence in this solution is still low at this point. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 542 PM MDT Mon Apr 15 2024 Strong winds will affect most terminals through the early evening hours, especially at KCYS and LAR where gusts over 45 knots will be possible. Expect scattered cloud ceilings generally above MVFR thresholds. After midnight, temperatures will cool out west and will transition to a rain/snow mix. Some IFR ceilings are possible at LAR, CYS, RWL, and BFF through the morning hours on Wednesday. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...High Wind Warning from 3 AM to 3 PM MDT Tuesday for WYZ101. High Wind Warning until 3 PM MDT Tuesday for WYZ107-108. Winter Weather Advisory until 3 PM MDT Tuesday for WYZ112. Winter Storm Warning until 3 PM MDT Tuesday for WYZ114. High Wind Warning until 6 PM MDT Tuesday for WYZ116-117. Winter Weather Advisory until 3 PM MDT Tuesday for WYZ116. High Wind Warning until 6 PM MDT Tuesday for WYZ118-119. NE...High Wind Warning from 9 AM to 6 PM MDT Tuesday for NEZ019>021- 054-055. && $$ UPDATE...TJT SHORT TERM...GCC LONG TERM...RUBIN AVIATION...MAC
Area Forecast Discussion
National Weather Service Hastings NE
909 PM CDT Mon Apr 15 2024 ...Short Term Convective Update... .KEY MESSAGES... - Thunderstorms develop and move through the area tonight. A few storms are possible as early as 6pm, but the main timeframe is expected to be 10pm to 4am. - Tornadoes, very large hail, and damaging winds are all possible. And this threat continues well into the overnight. - Additional rain and thunderstorms are expected Tuesday, especially across Nebraska, but the main severe risk will shift east of us. - Turning cooler through the week and into the weekend, with off and on precipitation chances. && .UPDATE... Issued at 909 PM CDT Mon Apr 15 2024 - Various notes regarding the overnight severe weather threat: 1) A legitimate severe storm threat with all hazards possible (large hail, damaging winds, a few tornadoes) most definitely STILL EXISTS for the vast majority of our coverage area (CWA) overnight, and recently issued Tornado Watch 113 is currently valid until 3 AM for all of our KS counties along with our NE counties along/south of I-80 and along/west of Highway 281. Further overnight expansion of this Watch (or perhaps a new Watch) is quite possible. 2) Potential development several hours ago (that prompted the since cancelled/replaced Severe T-storm Watch for 4 of our west-northwestern most counties) ended up tracking well- northwest of our CWA, with capping keeping any other convection at bay locally. 3) This always was expected to be a MAINLY OVERNIGHT (aka late) "main show" for our CWA, which is actually a bit unusual for so early in the convective season. Above all else, folks need to remain unusually vigilant and have a way to receive Warnings at a time of night that may be more common in June than April. 4) Going into some basics of the meteorology/expectations: - The recently-developed showers/weak thunderstorms in our southeast counties are not of significant concern for a severe threat (they are elevated), but will be watched closely. - As the large-scale Pacific cold front intercepts the well- defined dryline in western KS/NE and large-scale ascent increases ahead of the vigorous closed upper low shifting across central CO, rapid/intense storm development is likely mainly 10 PM-Midnight within or just south of our far western and southwestern CWA (particularly near/west of Hwy 183). - Initial storms could quickly become supercells, and at least briefly maintain some isolation (this would be the peak time of large hail threat). However, especially by around/after 1 AM, storm mode will likely become quite "messy", with clusters or line segments racing north-northeast across the majority of our CWA (but with the most intense activity probably favoring the southern and eastern halves of it). - As things trend "messier" in storm mode, the large hail threat would likely decrease, but as long as storms remain surface- based, a damaging wind and QLCS tornado threat (meaning tornadoes embedded within kinks in the line or along any breaks in a line) would remain a threat, especially given strong low level (0-1km) shear ramping up to 30-40KT. - Latest hi-res models (including HRRR) suggest our severe storm threat should vacate our eastern CWA by the 5-7 AM time frame (again unusually late at night/early in the morning for our area!). - Briefly touching on TUESDAY DAYTIME (after 7 AM): Although the MAIN severe weather threat should clearly be to our east, there will likely be enough residual instability under the heart of the closed upper low as it tracks directly overhead to prompt a few strong to MAYBE marginally-severe storms with mainly a hail threat (up to around 1" size), especially early- mid afternoon. This, however, is not a "sure thing" as we are overall-far more concerned with the upcoming overnight. && .DISCUSSION... Issued at 330 PM CDT Mon Apr 15 2024 Returning moisture and diurnal heating ahead of an upper low has pushed MLCAPE values as high as 3000J/kg in southwestern portions of the area. Latest satellite shows cumulus development stretching from near North Platte down to near Beloit. This cumulus doesn`t seem to be developing quickly, and there is still some uncertainty on when this will develop. The HRRR keeps our entire area convection-free until almost midnight, but the NAMnest shows convective development within the next 1-2 hours. Regardless, the expectation is that this first round of thunderstorms (wherever they develop) will be primarily a hail threat with steep midlevel lapse rates and relatively limited low-level shear. Around sunset, increasing low level shear and helicity will lead to increasing tornado threat, and better forcing arriving from the west should allow for additional thunderstorms to develop overhead or just to our southwest late this evening (after 10pm). This activity will then move through the area into the late overnight, with continued threats for damaging hail, wind and tornadoes. The tornado threat will likely be greatest along the southern extent of the cluster/line. Storms push to our east Tuesday morning, but additional showers and thunderstorms are expected to develop as the upper low moves through the area. Instability will be much more limited on Tuesday, so severe weather is unlikely. Winds will turn to the northwest behind the low Tuesday evening into the overnight, and gusts of 40-50 MPH are expected. Another shortwave will bring us another chance for precipitation Wednesday night into Thursday morning (along with a shot of cooler air). This should be primarily rain (and some weak thunderstorms), but a mix of rain/snow is possible Thursday morning as surface temperatures fall into the 30s. A upper low over Manitoba will keep us in a cooler pattern into next weekend, with spotty precipitation chances each day. Subfreezing temperatures appear likely Saturday night. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 536 PM CDT Mon Apr 15 2024 Severe storms possible tonight for the TAF sites. Decided to add TSRA on station for GRI overnight as short range models seem to have some agreement on timing. Hail and wind will be the primary threats with these storms, but an isolated tornado cannot be ruled out either. The winds will remain gusty for the most part, but winds do taper off a little as the low pressure center moves over the sites and the winds will pickup once the low moves off. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ UPDATE...Pfannkuch DISCUSSION...Mangels AVIATION...Beda
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1049 PM CDT Mon Apr 15 2024 .UPDATE... Issued at 952 PM CDT Mon Apr 15 2024 Despite plenty of instability there is little in the way of forcing with the warm front as it slowly lifts northward, thus lowered POPs for tonight (20 percent most locations). Byrd && .KEY MESSAGES... - Scattered thunderstorms (up to a 40% chance) remain possible through this evening. One or two of these storms could become severe, with quarter size hail and gusty winds being the main threats. - Severe thunderstorms look likely on Tuesday during the afternoon and early evening hours, particularly across central and northeast Missouri into west central Illinois. Large hail, damaging winds, and tornadoes are all possible, with the area mentioned above at risk for very large hail and a strong tornado. && .SHORT TERM... (Through Late Tuesday Night) Issued at 357 PM CDT Mon Apr 15 2024 Latest surface analysis is showing a front extending from just north of Kansas City to near St. Louis to north Evansville. Latest satellite imagery is showing a cumulus field south of this front where the SPC mesoanalysis is showing MLCAPES of 1500-2000+ J/kg. The latest HRRR/RAP is showing the front remaining in the place this evening with a isolated-scattered thunderstorms developing along the front as the cap breaks between 23-02Z. One or two of these storms may become severe given the amount of instability and deep layer shear around 30 knots. Then the HRRR is showing any storms moving out of the area by late this evening with a chance of showers overnight. More active weather will occur with two waves of severe weather likely on Tuesday. The aforementioned front will move north of the area early in the day in response to a deep surface low moving east across Nebraska. This will put us in the open warm sector with the first round forced by a combination of mid level lead shortwave paired with a band of low level moisture advection. The HRRR has been consistent in showing a north-south band of showers and thunderstorms across the CWA between 12-5 pm. MLCAPES will be around 1000 J/kg ahead of this band with deep layer shear of 50-60kts indicating that supercells and organized mutlicells will be possible within this band capable of producing large hail, damaging winds, and a tornado or two. The second band will likely occur between 4-8 pm ahead of a weak vort lobe paired with a dry line. The HRRR have been showing discrete cells developing ahead of the dryline where there are forecast hodographs with large curvature in the 0-3km layer and 0-1km shear of 35 knots. While there are questions about whether there will be enough time to destabilize behind the first wave, the NAM/GFS is showing MLCAPES of 1000-1500 J/kg in the area that these storm develop in which does support the SPC Enhanced risk and the potential for very large hail and a strong tornado with these storms. This line will likely move out of the CWA by mid-late evening leaving the overnight hours dry. Britt && .LONG TERM... (Wednesday through Next Monday) Issued at 357 PM CDT Mon Apr 15 2024 Mainly dry weather is expected on Wednesday and Wednesday night before a northern stream system brings a cold front through the area. The LREF supports likely PoPs late Thursday into Thursday night. Showers and thunderstorms will linger over the area into Saturday before Sunday will be dry. Temperatures will remain above normal into Thursday before falling below normal behind the cold front on Thursday. Britt && .AVIATION... (For the 06z TAFs through 06z Tuesday Night) Issued at 1047 PM CDT Mon Apr 15 2024 With lack of forcing along the warm front that is slowly lifting northward overnight, little in the way of additional storms expected to develop, thus kept all TAFs dry through the overnight hours. Main round of activity will fire up after 15z Tuesday and slide east across the region through the afternoon and early evening hours. Second round with a dry line, looking less likely per the lastest CAMs, so TAFs are dry after 00z-03z Wednesday. Otherwise, southeast winds will veer to the south by mid morning on Tuesday and pickup with gusts near 35kts at times. Byrd && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Morristown TN
1017 PM EDT Mon Apr 15 2024 ...New UPDATE... .UPDATE... Issued at 959 PM EDT Mon Apr 15 2024 Recent HRRR soundings suggest a low level inversion has developed following the setting sun. This is further backed up by SPC Mesoanalysis which shows that weak convective inhibition has developed across much of the area. Additionally, surface observations suggest that the better convergence along a weak boundary remains displaced more so towards northern Kentucky. This has resulted in the severe threat for southwest Virginia and extreme northeast Tennessee trending downward and the most recent convective outlook has been limited to a marginal risk. Given DCAPE ranging from 700 to 1000J/kg and steep lapse rates, if an isolated storm does drift into the region some gusty winds and small hail will be possible. Otherwise, a fairly quiet night with bands of mid to high level clouds streaming ahead. Temperatures will sit comfortably in the upper 50s to low 60s for the morning commute. && .SHORT TERM... (This evening through Tuesday) Issued at 310 PM EDT Mon Apr 15 2024 Key Messages: 1.Chance of showers and thunderstorms in northern sections this evening, with a few storms capable of producing large hail and damaging winds. Storms possible in NE sections again Tuesday afternoon. 2. Above normal temperatures continue for Tuesday, with highs in the 80s in most spots. Discussion: Convection has begun to develop along a pre-frontal trough across northern WV/VA. In the next few hours, the CAMS show additional development farther west, across southern OH/northern KY. This expected activity will propagate SE, and could reach our SW VA counties in the 00-06Z time frame. Right now, that area is capped, but RAP mesoanalysis shows weakening CIN in the next few hours. Given the steep midlevel lapse rates leading to MLCAPE near 2000J/kg, low WBZ heights, and adequate shear, large hail may be a threat with the storms, along with damaging wind gusts. CAMS have some discrepancies about when this activity will dissipate, but expect a downward trend from 04-08Z as the boundary layer stabilizes. A 850-700 mb ridge axis crosses the area in the morning, with a weak shortwave trough following behind it in the afternoon. With afternoon heating and MLCAPE developing to near 1500 J/kg in NE TN/SW VA, some strong to severe storms will be possible again, although lapse rates are not as steep as this evening. Warm temperatures can be expected again tomorrow, with highs well into the 80s for most locations outside the mountains. && .LONG TERM... (Tuesday night through next Monday) Issued at 310 PM EDT Mon Apr 15 2024 Key Messages: 1. Increasing rain chances with showers and thunderstorms Wednesday. A break in the rain Thursday. Rain chances increase with a chance for more thunderstorms Friday and Saturday. 2. Turning much cooler Sunday and Monday behind cold front. Lingering rain chances through at least Sunday with slowing of front. Discussion: Tuesday night the strong upper level ridge over the east and southeast will continue to combine with a low level southerly flow and increase warm advection into the region. After a very warm day Tuesday and increasing clouds Tuesday evening temperatures will be slow to fall. Lows expected in the lower to mid 60s. An approaching low pressure system into the Great Lakes pushes a cold front through the Tennessee Valley Wednesday. Models are showing a weakening trend with this front as it shifts east as main system goes far to the north. Have kept higher rain chances then MAV/MET blend. ECMWF only model keeping the front and precipitation widespread with the other 2 models drier. Some storms that are able to form could still get moderate instability and shear late in the day with ample daytime heating into the mid to upper 70s and dew points in the upper 50s to near 60 along the plateau and southern valley. The plateau area should see the highest risk with marginal damage possible. The weak front should move east Wednesday night with a dry and continued warm day Thursday as no cold air will follow this front. Weak high pressure will slowly slide east late Thursday and Thursday night. A new low pressure area forms across the western southern plains Wednesday night and Thursday. This weaker low and system will be a slower mover and ECMWF shows it weakening as it approaches Friday night. Not much shower and thunderstorm activity moves in with most of the convection to the southwest of the local area. The GFS shows a little more convection Friday but again shows redevelopment far to the west. It looks like overrunning along the front will bring more significant rainfall across the region Saturday and Sunday with the ECMWF and the GFS only Sunday. With the uncertainty Have rain chances through the weekend. Monday the front shifts east. Above normal temperatures will continue through Friday then cooling down Saturday and much cooler Sunday and Monday with highs only in the upper 50s to mid 60s. && .AVIATION... (00Z TAFS) Issued at 737 PM EDT Mon Apr 15 2024 Some hi-resolution guidance continues to show a few isolated showers/storms developing near southwest Virginia and northeast Tennessee tonight. Have included vicinity thunder mention at TRI but confidence is quite low in any direct impacts to the terminal. Most likely timing seems to be through about 6z. Otherwise, mid to high level clouds stream across the area with light winds through TAF period. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 61 85 64 77 / 0 0 20 50 Knoxville McGhee Tyson Airport, TN 62 85 65 77 / 10 10 10 40 Oak Ridge, TN 61 85 63 77 / 0 10 20 50 Tri Cities Airport, TN 59 81 60 78 / 20 20 10 20 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...DGS LONG TERM....TD AVIATION...KRS
Area Forecast Discussion
National Weather Service Springfield MO
604 PM CDT Mon Apr 15 2024 .KEY MESSAGES... - Potential for isolated thunderstorms this evening. Marginal severe risk across central MO with large hail the primary risk. - Potential for isolated to scattered strong to severe thunderstorms across the area Tuesday. Large hail and damaging winds the primary risks. Confidence remains limited. Stay tuned for updates. - Windy conditions will develop on Tuesday with south winds gusting up to 40-50+ mph at times. - Strong to severe thunderstorms possible on Thursday. && .SHORT TERM /THROUGH TUESDAY NIGHT/... Issued at 137 PM CDT Mon Apr 15 2024 This evening into tonight: A warm front is currently sitting across the highway 54 corridor and slowly drifting northward. Some convection may fire along the front, bringing a risk for 1" hail, but chances that storms fire in our CWA are less than 20%. Overall severe risk is less given conditionality of severe threat, small area and time window where storms may develop, and limited chances for convection to initiate in the first place. Overnight tonight may see some patches of rain move through, but most locations should stay dry. For Tuesday, the strong, stacked low pressure system that is driving short term conditions will shift from NE to IA, this results in the CWA bring between better forcing further north closer to the low and further south where better instability should exist. In fact, the mid-level jet right exit region will be over the CWA, resulting in upper confluence and downward motion. The airmass will not feature a lot of moisture throughout the profile and a dry line will surge in from the west, further reducing potential for sustained convection and limiting coverage. But, if convection can become established and enough instability can develop, shear will be strong (deep layer shear around 70 kts) so severe storms will be possible. Current thinking is that the best potential for storms will be over the northeastern and eastern CWA in the afternoon and evening, but still featuring limited PoPs of <50% over most of the area. Main hazards would be large hail and damaging winds. There remains considerable uncertainty on the coverage and potential for storms, the amount of instability that can be realized, and resulting hazards. Stay tuned for updates. The greater likelihood of impacts lies with gusty southerly winds on Tuesday, especially over the western CWA where the dry line moves through earlier in the day, resulting in increased mixing. Could see gusts of 45-55 mph along and west of Highway 65. There may also exist a fire weather threat over the west depending on the level of mixing and surface RH values. HRRR shows RH values into the teens in the afternoon west of Highway 65. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 137 PM CDT Mon Apr 15 2024 Wednesday will see breezy westerly winds, highs in the 70s to mid 80s, and sunny skies. For Thursday, SPC has the equivalent to a slight risk over the southwestern CWA. Guidance shows a warm front across the area with a surface low moving up the front in the afternoon as shortwave energy moves through. There is considerable uncertainty in how much morning precipitation will be around and resulting afternoon instability. Current forecast calls for highs ranging from the low 70s NW to the mid 80s S. If ideal conditions can develop, deep layer shear around 50 kts with favorable arcing hodographs and SBCAPE values up to around 2,000 J/kg are possible. Severe weather with all hazard modes would be possible. Stay tuned. Unsettled conditions are possible Friday and Saturday with 20-30% chances for showers and highs in the 50s and 60s. Sunday and Monday look dry with highs in the 60s. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 602 PM CDT Mon Apr 15 2024 Some mid level cloud cover can be expected this evening into the first part of the overnight hours ahead of a strong low pressure system in the plains. Eventually ceilings will dip into the MVFR category and some scattered convection will be possible at the TAF sites from around sunrise through the midday hours. Very gusty winds out of the south are expected with some gusts over 30 kts possible. && .SGF WATCHES/WARNINGS/ADVISORIES... KS...None. MO...None. && $$ SHORT TERM...Titus LONG TERM...Titus AVIATION...Lindenberg