Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/20/22

Area Forecast Discussion
National Weather Service La Crosse WI
648 PM CDT Thu May 19 2022 .DISCUSSION...(This evening through Thursday) Issued at 254 PM CDT Thu May 19 2022 Key Messages: - Severe weather expected this afternoon and evening - Frost/Freeze Headlines Maybe Needed Sunday Night Late This Afternoon and Evening... Continuing to monitor the northward progression of a warm front which extends from Albert Lea, MN to Platteville, WI. Temperatures south of this warm front range from the mid-80s to lower 90s. Dew points have dropped into the 50s in the wake of this mornings convection. Further to the southwest, the dew points range from the mid-60s to lower 70s. There is still some questions how much moisture recovery there will be in the warm sector. The latest HRRR has a good handle on the current dew points and it shows that the dew points will recover into the lower 60s. Until that moisture gets back into the area, there may be a lull in convection in this area. Soundings show an inverted V in this area, so there will be a threat of damaging winds and large hail once the convection returns to this area between 5 PM and 7 PM. Meanwhile, along the warm front, VWP is showing backing winds at KLSE and this lengthening the 0-3 km hodograph. The RAP and HRRR indicate helicities increasing into the 300 to 400. The 0-1 km computed CAPES will likely climb into the 800 to 1200 J/kg range. The highest values look to be from the Iowa/Minnesota boarder north into southeast Minnesota and maybe the counties bordering the Mississippi in Wisconsin. This tornado threat looks to be from 4 PM to 7 PM. As the cold front approaches and the moves into the narrow ribbon of return moisture, there will a line of storms developing along the cold front. These storms will be capable of producing large hail and damaging winds. There is still some uncertainty on how far south the storms will develop into the warm sector. Sunday through Thursday... Precipitation chances continue into Sunday morning as an upper level trough moves over the area. As the trough lifts out of the area, precipitation could linger over our northern counties into early Sunday afternoon. High temperatures will remain in the upper 50s/low 60s during the day, and with clouds moving out overnight, low temperatures could drop down to the low/mid 30s for some. Frost/freeze headlines may be needed Monday morning. Although the end of the weekend into Monday appears to be dry, increasing chances for precipitation returns through the week. While ensemble solutions show increasing agreement on upper level troughing moving across the area midweek, there are differences in the progression of the trough. With this disagreement, differences in the timing and coverage of precipitation across the area remains. Temperatures will return to the low/mid 60s for the start of the week. However, EPS solutions suggest an upward trend in temperatures into the weekend, with ensemble means above model climatology. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 647 PM CDT Thu May 19 2022 A line of showers and storms over KRST will slowly sag into KLSE between 20.01Z and 20.02z. Ceilings will range between 5 and 10K feet. A few of the thunderstorms may become severe. Damaging winds and hail are the main concerns. Visibilities at times may become IFR/MVFR this evening in some places, but confidence was not high enough to include them in the TAFs at this time. The thunderstorms will gradually come to an end between 20.05z and 20.07z. While the thunderstorms will be ending scattered showers will continue for much of the remainder of the night. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ DISCUSSION...Boyne/EMS AVIATION...Boyne
Area Forecast Discussion
National Weather Service Columbia SC
808 PM EDT Thu May 19 2022 .SYNOPSIS... Warming trend continues through the end of the week with temperatures well above average. Isolated thunderstorms mainly across the northern Midlands this afternoon and evening, with isolated severe weather possible. Better rain chances return this weekend as a frontal boundary moves into the region. && .NEAR TERM /THROUGH TONIGHT/... Showers and storms have stayed well away from our cwa this evening, and expecting a dry period overnight. Latest hrrr shows no activity through the night, with the nearest showers remaining closer to the NC/VA border. Skies will remain mostly clear with only some thin cirrus moving through. Winds not expected to go calm, but should drop off to around 5 knots. With the winds, do not expect fog. Expect overnight lows in the upper 60s to around 70 degrees. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... Rising heights and dry air intrusion Friday with PWATs dropping to around 1.1 to 1.2 inches. Temperatures likely a degree or two warmer across the area with the exception of the CSRA where a bit of high clouds will push in during the afternoon but otherwise expect mostly sunny skies. Highs once again in the mid to upper 90s. Moisture begins to return Friday night as the ridge axis shifts offshore and deep southerly flow returns to the forecast area. Temperatures overnight remain mild with lows around 70 as clouds increase in coverage. A shortwave will push through a weakness in the ridge Saturday with showers and storms possible especially in the afternoon, with highest chances in the CSRA. While forcing from the shortwave will make coverage highest in the CSRA, diurnal storms will still be possible elsewhere as we head into a more summer- like pattern. Weak shear expected limiting the severe threat although some dry air may enhance downdrafts. With increased cloudiness as well as higher chances for precipitation, temperatures will be lower although with at least some weak ridging in place, still expect temperatures above average in the low to mid 90s. Another mild night Saturday night with lows in the upper 60s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... A warm, moist pattern is expected to persist through the long term period with additional forcing provided by an approaching cold front into early next week. Ensembles indicate PWATs will remain above the 90th percentile, with most members remaining above 1.5 inches through the extended period. This will continue to support an unsettled pattern, further enhanced by the approaching front which will likely stall near the area. Generally storms will continue to be diurnally driven with limited chances for severe weather. Blended guidance continues to support temperatures near average in the long term, trending away from cooler conditions of previous runs and the current forecast reflects that. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... VFR conditions likely through the 24 hour TAF period. Convection over the Appalachians and along the sea breeze has struggled to develop so showers and thunderstorms should not impact the TAF sites this evening. Relatively dry air and a 30kt LLJ should prevent widespread fog or stratus overnight. The HRRR keeps a stratus deck south of the forecast area where moisture is deeper, adding confidence to a VFR forecast. Upper ridging and limited atmospheric moisture will prevent moist convection on Friday leading to a dry forecast. Winds will pick up around or shortly after 15Z out of the SW around 10 kts with gusts up to 20 kts. EXTENDED AVIATION OUTLOOK...This weekend: showers and thunderstorms, mainly in the afternoon and fog and/or stratus possible each morning. This pattern persists into early next week. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service State College PA
1118 PM EDT Thu May 19 2022 .SYNOPSIS... Fair and mild conditions will prevail tonight with areas of fog forming after midnight. Hot and humid weather arrives for Friday afternoon and will continue through much of the upcoming weekend. This will feature the hottest weather since last summer to central PA with record challenging/breaking temperatures Friday into the weekend. A cluster of showers and thunderstorms could dampen the morning and midday hours Friday, mainly across the southern half of Pennsylvania, as they moves east from the Ohio River Valley. Otherwise, isolated afternoon and evening thunderstorms are possible Friday and Saturday. Showers and thunderstorms are most likely on Sunday as a strong cold front moves across the Commonwealth. Conditions dry out to start next week with noticeably cooler temperatures and much lower humidity. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... 1045PM update... A few clusters of thunderstorms continue across the Ohio Valley this evening. The initial MCS, currently over southern Ohio, should arrive in our CWA between 8z-11z. It will most likely weaken to just showers or low clouds given that it will travel down a steep gradient in CAPE. Therefore we aren`t expecting thunderstorms before daybreak, but showers are possible in the Laurel Highlands. From previous... Comfortable conditions prevailing this evening thanks to advection of lower dewpoints all the way into the Lower Susq River Valley. Evening temps are ranging through the 70s with dewpoints ranging through the 40s to near 50F south with a light breeze. Lows will generally be in the 50s. Patchy fog is possible after midnight under mainly clear skies with decreasing wind. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... 11 PM Update... Additional MCSs (or their remnants) upstream are progged to arrive at our CWA between 14-16z. The last few runs of the HRRR show an intensifying MCS near I-99 by noon and pushing into eastern PA through the late afternoon hours. As the MCS enters the Lower Susq around 18z, the HRRR shows it tapping 2000-2500 J/kg MLCAPE, 35-40 kt 0-3 km SWrly shear, and 40-45 kts 0-6 km WSW shear, parameters which suggest severe wind potential with the MCS at least over our southeastern zones and maybe extending northward through the Susq valley. SPC will consider upgrading the MRGL to a SLGT for Fri on the overnight update, but they do point out uncertainty with timing and CI. Although a large majority of the severe potential appears to be with linear convection between 14-20z, we can`t rule out isolated severe discrete cells developing behind the MCS through the early evening hours. CAPE will likely rebound to 2000+ J/kg over western zones as temps warm into the 80s. Low level wind shear and veering will remain strong as warm air advection commences behind the warm front. CI will depend on the presence of triggers (perhaps intersecting cold pools and/or terrain?), but there is a conditional risk for isolated severe weather after 20z if any deep convection does develop. From previous... High temps now look like they`ll be impacted by clouds and convective cold pools, with consensus of NAM, NAM12, HRRR indicating significantly cooler maxes than we have out. Even NBM has lowered from previous solutions, and we believe maxes will be 3-5 degrees lower than previously forecast as a result. Have knocked down Friday afternoon highs as a result with this evening (Thu) update. Went with the mid range of QPF solutions at this point and painted 2-3 tenths across the Central and Southern part of the CWA. Should the MCS follow in line with several of the Hi res members, rainfall amounts could be locally 0.5-1.0 from a few TSRA tracking over the same location. *Surge of summerlike heat and humidity will bring the hottest weather since last summer to central PA with record challenging/breaking temperatures Saturday *Be mindful of heat stress impacts given limited exposure and acclimation this early in the year. Stay hydrated! Broad southwest flow will contribute to a surge of summerlike heat & humidity to close out the week as an anomalous upper ridge builds over the Eastern U.S. High temps Friday still progged to recover into the upper 70s and 80s for most, but the real heat comes on Saturday with some record challenging maxTs Saturday afternoon. Very muggy conditions in store for Friday night with lows holding in the 60s or +15-25F above normal. These low temperatures are likely to daily record maxi- mins (record warm low temperatures) across most of the area. See the Climate section for context on possible record warmth. && .LONG TERM /SATURDAY THROUGH THURSDAY/... An amplified upper ridge of high pressure will situation itself over the US East Coast late this week into the weekend, funneling Gulf moisture and enhanced warmth into the Keystone State. Dewpoints surge into the mid 60s with max Ts reaching well through the 80s and lower 90s. GEFS highlights greatest areas to see temps above 90 on Saturday in the far SE, south central PA, and middle susq valleys. Record daily high temperatures will be approached at all climate sites in our area (see climate section of the AFD). Early arrival of unseasonable heat will be impactful despite Heat Advisory criteria not being reached. Sunny skies will start Saturday off (wear your sunscreen!), but afternoon cumulus may develop off the higher terrain and move east. Something to watch is interactions with the Erie lake breeze for stronger convection to fire and move SE into our NW counties. Instability will be high with the hot and steamy surface conditions, and deep layer shear will be sufficient enough to support organized storms. Outside of NW PA, there will be little forcing for storm development, though an isolated t-storm cannot be ruled out for Saturday afternoon. Saturday night will be warm once again as 850 temps remain in the 15-20C range. Record daily min Ts will likely be broken again. For Sunday, an approaching cold front out of the Ohio River Valley will increase storm chances for Sunday afternoon. Temperatures will still be hot ahead of the front - upper 80s to low 90s - and dew points still juicy in the mid 60s. Storms Sunday afternoon could be strong to severe with favorable instability, but marginal shear. the greatest severe risk is highlighted in SPC D4 outlook which has a 15% threat area across our northern counties where the shear will be most suitable for damaging winds. The cold front will cross our area through Sunday evening and overnight, ushering in a more comfortable airmass. Monday and Tuesday will be drier and cooler with high temps in the 70s both days. Chances of rain showers will be non-zero in the southeast those days with onshore flow developing from a surface high off to our northeast. Isolated showers, clouds, and cooler weather lasts through most of Wednesday, then models begin to diverge on the progression of a low pressure system moving out of the Midwest and over the Great Lakes region. Depending on how the low evolves, we may see more showers and storms Wednesday night through Friday, but a lot of uncertainty exists. If it remains unsettled and stormy, temperatures will also stay cooler and in the 70s from abundant cloud cover. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... Winds diminish quickly this evening and much of the night will be fair and VFR. Some marginal 30 kt LLWS is possible around daybreak as SW flow strengthens to near 40 kts at 2kft and winds remain 10 kts or less near the ground. There is still a chance for patchy fog, but coverage will likely be limited by mid and high clouds resulting in inefficient radiative cooling. Some remaining wind will also disrupt fog formation. Areas of MVFR to IFR cigs and vsby will develop early Fri morning across mainly the southern and western airfields as a cluster of showers and TSRA moves east from the Ohio Valley. A few storms may be severe, particularly across the southeast. By late Fri afternoon, most places will improve to VFR outside of scattered thunderstorms. Low level wind shear will increase Fri night in a warm air advection regime as SW flow increases to 40-50 kts at 2kft AGL. Outlook... Sat...Primarily VFR, although an isolated late-day TSRA is possible. Sun...Numerous SHRA/TSRA with cold frontal passage. Mon...Lingering SHRA across the southeast. Tue...Scattered SHRA mainly across the south && .CLIMATE... Near-record warmth is possible Friday night through Sunday morning across Central Pennsylvania. Several locations are also likely to have their first 90F day so far this year. NBM probabilities of temperatures greater than 90F on Saturday are >75% for almost all of Pennsylvania. Although nowhere near the earliest first occurrence of 90F, it would be a week or two ahead of average for most of the area. Daily record highs for Friday 5/20 and Saturday 5/21: MDT 94/1996 | 95/1941 IPT 96/1996 | 95/1941 AOO 92/1996 | 89/1977 BFD 86/2021 | 86/2021 STC 91/1996 | 91/1941 Daily record warm lows (maxi-mins) for Saturday 5/21 and Sunday 5/22: MDT 68/2004 | 69/1911 IPT 65/1911 | 66/1959,1911 AOO 68/1975 | 66/2018 BFD 63/1959 | 62/2013,1984 STC 72/1996 | 69/2013 && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert/DeVoir/Steinbugl NEAR TERM...Lambert/DeVoir/Colbert SHORT TERM...Lambert/DeVoir/Colbert LONG TERM...DeVoir/Wagner AVIATION...Lambert/Colbert CLIMATE...
Area Forecast Discussion
National Weather Service Dodge City KS
527 PM CDT Thu May 19 2022 ...updated aviation section... .SHORT TERM...(This evening through Friday) Issued at 318 PM CDT Thu May 19 2022 Strong southerly winds will continue this evening into the early part of the overnight period with an increase in high level cloudiness. After midnight, a strong cold front will sweep through western Kansas and envelop the entire CWA by sunrise tomorrow. This will shift winds to the north with an increase in speed. Wind speeds will be the highest shortly after fropa with a slight decrease as the day progresses. None the less, strong northerly winds will be felt throughout the day. Dry air will filter in behind this front with mostly clear skies expected through tomorrow. As for temperatures, lows tonight are expected to range from the mid 40s across west central Kansas to low 60s across south central Kansas. Highs tomorrow look to range from around 70 degrees across west central Kansas to upper 70s along the KS/OK border. .LONG TERM...(Friday night through Thursday) Issued at 318 PM CDT Thu May 19 2022 Cold air advection continues Friday night through Saturday with an increase in cloudiness. A chance of precipitation will be possible across west central Kansas and along the I-70 corridor with a few sprinkles anticipated elsewhere. Northerly winds continue through Saturday night then shift to the south Sunday as the area of high pressure shifts eastward. Cloudiness will also decrease in coverage Sunday. The next system starts to affect western Kansas Monday and continues into the mid part of next week as a shortwave digs into the Central Rockies and spins into an upper level low by Tuesday night. Ensemble models then diverge on the track of this system with the operational GFS sliding this feature to the south of the area with the operational ECMWF having this feature trekking to the north. Nevertheless, the probability of precipitation look increase during the first part of next week. As for temperatures, below normal highs are expected Saturday with mostly places only reaching into the 50s with around 60 degrees along the KS/OK border. Highs then moderate into the 60s Sunday and Monday with 70s returning by mid week. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 525 PM CDT Thu May 19 2022 A Nebraska cold front will move southward over the heart of the area by Midnight, and then into Oklahoma by 12z Saturday. An increase in cloud cover overnight will be limited to high and mid levels, with very high ceilings that won`t impact terminals. One caveat is near the HYS terminal where HREF low Layer Cloud mean image has around a 25 percent chance of lower stratus behind the front towards the 10 to 14z timeframe - still quite low. HRRR visibility fields show unlimited vsby area-wide Tonight. && .PRELIMINARY POINT TEMPS/POPS... DDC 53 76 43 57 / 0 0 10 0 GCK 51 73 41 55 / 0 0 10 10 EHA 51 76 41 58 / 0 0 0 10 LBL 54 76 43 59 / 0 0 0 0 HYS 52 73 43 54 / 10 0 20 10 P28 61 80 51 61 / 0 10 20 0 && .DDC WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 9 PM CDT /8 PM MDT/ this evening for KSZ043-061>063-074>076-084>086. && $$ SHORT TERM...Hovorka_42 LONG TERM...Hovorka_42 AVIATION...Russell
Area Forecast Discussion
National Weather Service Des Moines IA
625 PM CDT Thu May 19 2022 .UPDATE... Issued at 613 PM CDT Thu May 19 2022 The scenario of the warm front surging into Minnesota and placing the better wind shear environment closer to Interstate 90 has played out thus far. Therefore, our northern counties have not seen much in the way of discrete activity. This has been occurring in southeast Minnesota and southwest Wisconsin. A few elevated supercells also occurred north of the warm front closer to the MSP metro. As of 2230z, there were few updrafts going up along Hwy. 18 in far northern Iowa. Day cloud phase satellite imagery did show slightly deeper cumulus clouds developing, and some weaker reflectivity values were showing up the KDMX and KMPX radars. For now, expect initiation to happen in far northern Iowa, but the storms will need to move northeast closer to the warm front to realize the 0-500m SRH above 100 m^2/s^2. Upper-air soundings launched by the TORUS Field Campaign have indicated strong boundary layer mixing on the warm side of the warm front, with dewpoint depressions over 30F. At the start, convection likely had a hard time going because of dry air entrainment. Now with several failed attempts, there probably has been in an increase in mid-level moisture that allowed subsequent convection to become deeper. However, the cloud bases remained high with LCLs over 1500m, and over 2000m in some places, and therefore not realizing any low-level helicity. The WoFS members have drastically backed off the UH tracks south of Interstate 90, matching the trends we were seeing in radar. A few thunderstorms are expected across northern Iowa. The tornado threat has greatly diminished. With the strong mixing, theta-e deficits from the surface to the top of boundary layer have increased. If a thunderstorm becomes mature, a strong cold pool could lead to damaging winds, and mid-level lapse rates may still support a hail threat. However, storms in northern Iowa likely will not become mature until they cross into Minnesota. Attention then turns to the dry line and cold front west of the area south of the main surface cyclone. Day cloud phase satellite has shown some cumulus developing over west-central Iowa in the past hour. Ahead of the cold front, is an airmass with dewpoints in the 60s, and MLCAPE values around 2000 J/kg. There still appears to be some weak capping, but not strong enough to hold back the convergence along the cold front. Earlier runs of the HRRR had little to no activity along the front. Since the 21z HRRR run, there is more activity which has been lining up with our thinking based on observational trends, and matches what other CAMs had at their 12z morning runs. WoFS members do not have much along the line, but today the WoFS seemed to need CI before it could catch onto the trends with the warm front. Therefore, will expect WoFS to provide better guidance after 00z, once more activity develops ahead of the cold front. The 0-6km bulk shear vector will be in excess of 40 kts, but mostly parallel to the cold front. The HRRR does not yet depict a textbook QLCS, rather the HRRR tries for discrete convection, and then develops more of an MCS. Current environmental parameters would suggest a QLCS mode is more favorable, somewhat similar the 12z NSSL- WRF solution from this morning. Straight line winds with a strong cold pool will be the main threat with storms/QLCS along the cold front. Initially, a few updrafts may produce hail, but this will likely be short lived. 0-3km bulk shear values will around 30-35 kts ahead of the boundary, but also oriented parallel. With this, still am not expecting a mesovortex generation threat. However, if a rear- inflow jet develops and orients a part of a line perpendicular to it, there may be some spin-ups. But, this does not seem highly probable. There is a shower along Hwy. 30, this could be the indication of initiation and that the cap is no longer a problem along the cold front. Some storms may become efficient rainfall producers, but should be progressive enough to not pose a major flash flood concern. Over the next hour, expect to see a few returns on radar from west-central Iowa to north-central Iowa. After 00z seems to be more favorable for storms to increase in coverage area. Check for subsequent MCDs from SPC this evening regarding convection along the cold front. The need for a Severe Thunderstorm Watch north of Interstate 80 may not be out of the question. && ...Updated for the 00z Aviation Discussion... .DISCUSSION.../Tonight through Thursday/ Issued at 235 PM CDT Thu May 19 2022 Key Messages: --Breezy and warm this afternoon. --Still watching potential for severe storms tonight. --Chilly and Rainy Saturday. --Frost Possible Sunday morning, otherwise clearing, cool, dry. --Multiple precipitation chances into mid-week with cooler temperatures continuing. TODAY THROUGH TONIGHT: A strong upper-level cyclone is moving from Montana into Minnesota today with a surface low that developed downstream and was located over southern South Dakota early this morning. An associated surface warm front was draped across northern/northeast Nebraska and northern Iowa ahead of the low which is expected to continue to push eastward into this evening hugging the Iowa/Minnesota border before moving a bit more northeast into southern Minnesota later tonight. This front was the spark of morning convection that caused scattered showers and thunderstorms across northern Iowa and initially produced pea size hail in Palo Alto county around 8am with a few cells that perked up along the Iowa/Minnesota border closer to 11am becoming a bit more robust with elevated storms that posed a large hail threat. Along/near the front and east of the surface low is the expected area for storms to fire this afternoon though a few caveats remain. For starters, a persistent MCS across Missouri and Kansas this morning did disrupt some of the moisture flow coming in from the south despite mid-level flow from the south/southwest ushering in warm, moist air into the state. By midday, temperatures across much of southern into central Iowa were already in the 80s with dew points in the 50s and 60s. Moisture return is a significant factor in the severe potential tonight, especially the tornado potential, which will need some of the more moist dew points in the 60s to reach the area of best lift near/along the warm front in northern Iowa. The morning storms did complicate the afternoon/evening forecast as the warm front appears to not be lifting north as quickly but if it does continue to push further northward, the severe threat, especially the tornado threat, may remain north of the IA/MN border as this boundary is definitely the area with the best potential for discrete supercells to form. Effective shear near the front is still around 35-40 knots, despite the better shear being behind the boundary. Storms that fire along the front will be capable of all severe threats - large 2"+ hail, damaging wind gusts and tornadoes. The window for tornadoes is pretty small, from roughly initial formation around 3-4pm or so and then continuing to maybe 6 or 7pm. Storms are expected to grow upscale and become more linear as the develop back to the southwest. This may end up being the better show for storms in our area, though definitely don`t want to discount the storm threat this afternoon in parts of northern Iowa with strong instability - upwards of 3000-4000 J/kg of CAPE in a band right through parts of western into central Iowa. To summarize, the tornado and large threat are the initial threats, trending to more of a wind threat as storms continue. One last note, the hodographs are very favorable if a discrete storm can persist. See the mesoanalyst discussion for further details in current storm thinking. FRIDAY/SATURDAY: Behind the cold front passage, much cooler air arrives as mid-level flow turns northerly to northwesterly into Friday. Temperatures Friday morning will be in the 50s across the northwest half with some 60s still remaining in the southeast half of the state as the cold front continues to progress through the state. The boundary stalls out to the south and east - across southern Missouri extending northeastward into Illinois - with a upper level positively tilted trough progressing eastward across the Mountain West through the day Friday. Some clearing is expected, especially later in the day Friday, with temperatures only climbing into the 60s to low 70s. The progressing trough will interact with the stalled boundary Saturday into Saturday night resulting in cloudy conditions with rain showers continuing off and on much of the day Saturday. H850 temperatures do drop to below freezing in northern Iowa on Saturday morning with continuing mid-level northerly flow helping to reinforce the colder air, but surface temperatures in the 50s will not force us to discuss any other precipitation types. Minimal instability with dew points in the 30s and 40s will generally keep us as all rain with current PWATs of 0.5- 1" not suggesting any significant QPF either. Regardless, it will certainly be chilly and wet Saturday for most. SUNDAY AND BEYOND: High pressure builds in Saturday evening into Sunday leading to clearing conditions which may drop temperatures into the mid to upper 30s, especially across northern Iowa, but also into the valley areas of western Iowa. This may ultimately require some frost headlines on Sunday morning before temperatures rebound into the upper 50s to 60s, though still below normal for this time of May. The 60s temperatures look to hang around into at least mid week with additional chances for precipitation on Monday into Tuesday and Tuesday night into Wednesday with a passing shortwave and low pressure system. Some spatial and timing differences remain within the models with the Canadian/Euro faster than the GFS and thus will continue to monitor trends over the coming days. && .AVIATION.../For the 00Z TAFS through 00Z Friday evening/ Issued at 625 PM CDT Thu May 19 2022 A cold front will sweep across the area later this evening and tonight, causing gusty SSW winds to veer around to NNW, then gradually diminish on Friday morning. Thunderstorms are also expected to develop along and accompany the front, affecting some terminals roughly between 03Z and 09Z as they progress east/northeastward. Expect MVFR or lower conditions as the storms pass through, and it also appears prevailing MVFR ceilings will follow the frontal passage and persist for a few hours before gradually rising back to VFR. Amendments are probable tonight based on short-term radar trends. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...Krull DISCUSSION...KCM AVIATION...Lee
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1151 PM EDT Thu May 19 2022 .AVIATION... Se Mi will lie between two MCS`s tonight. Remnants of the complex over Wisconsin will mainly produce ample mid and high clouds across Se Mi while the the better shower potential largely remains north and west of Se Mi. The convection across the Ohio Valley is aiding in the development of some low clouds across south central IL, forecast to advect into Se Mi toward 11 or 12Z Fri morning under increasing south flow. Model soundings show a deepening of the low level inversion toward daybreak which should be efficient at ducting the MVFR based clouds into Se Mi. Diurnal mixing will slowly lift the cloud bases before eroding the strato cu field early Fri afternoon. The deepening of the afternoon mixed layer combined with the strong SSW low level wind fields will support frequent gusts over 28 knots by mid/late Fri afternoon. For DTW...Current model solutions continue to advect an expanding MVFR stratus deck into metro around 11Z, with the latest RAP suggesting ceilings below 2k feet. After 15Z diurnal mixing will result in rapidly rising ceiling heights. .DTW THRESHOLD PROBABILITIES... * Moderate in ceilings below 5000 feet Friday morning. * Low in thunderstorms Friday night. && .PREV DISCUSSION... Issued at 408 PM EDT Thu May 19 2022 DISCUSSION... Warming trend continues through the remaining daylight hours today as H8 temps climb into the upper teens after a 10C start per 19.12Z KDTX RAOB. Warm pre-frontal environment isn`t particularly well defined yet with a gradual gradient in dewpoints from northern Lower into the Ohio Valley. Perturbed height field on the back edge of a shortwave trough affords sparse converge of a few additional isolated showers near the I-94 corridor before sunset. Lack of surface observational evidence suggested earlier reflectivity returns were just virga, but did include a small area of Slight Chance PoPs. Diverse cloud coverage depicted via GOES visible imagery this afternoon with plenty of areas receiving full insolation prior to diurnal cumulus generation paving the way for an easy run into the mid-upper 70s for highs. The warm front becomes better defined late this evening before lifting northward shortly after midnight. Lower column winds back southwesterly first with LLJ ramping up resulting in strong ThetaE convergence which moves H8-H7 layer dewpoints sharply higher. Did scale back PoPs during the late night hours given latest model trends suggesting difficulty in advecting ample mid-level moisture under persistent zonal flow which lingers downstream of the inbound longwave trough. Given that elevated nature of convection, this lends a lower confidence forecast. Once camp of solutions has a Vort Max off an orphaned shortwave feature lifting cyclonically toward Lake Erie and brushing the Metro regions resulting in some early morning showers. Not fully on-board with this as it`s just the NAM suite given a more westward displaced track. Questions remain Friday afternoon wrt to breaking the cap which currently appears inhibitive based on various forecast soundings. Minimal NWP evidence exists to defend even isolated coverage of surface-based parcels for most of the midday and afternoon hours across the central and southern areas. Not much in the way of dynamic ascent as the best CVA holds to the northwest. If any cap erosion does occur, SBCAPE would be in the 1500-2500 J/kg range posing a severe hail/wind threat. Applied numerous revisions to PoPs to reflect the lower probability scenario, even within the presence of decent elevated instability of H7-H5 lapse rates near 7.5 C/km and 25-30 knots of effective shear. As for temperatures trending into the mid-upper 80s and perhaps closer to 90F for areas closer to the MI/OH border, that aspect of the forecast remains well in-tact. Additionally, did nudge wind gusts up a few knots with the afternoon period which looks very supportive of gusts in the 30-40 mph range as boundary layer mixing taps into the enhanced LLJ at the base of the inversion layer. More sustained storm activity arrives during the evening and overnight hours as the cold front sags southeast amidst pre-frontal moisture pooling and FGEN context. The aforementioned cold front will stall and bisect Lower Michigan along an angle resulting in a period of wet weather for most of this weekend. The highest confidence for more cyclical rainfall occurs near the Tri-Cities which lies closest to boundary, but chances are favorable across most of Lower Michigan. Automated NBM PoPs of categorical might be a bit overdone. Temperatures cool off some 10 degrees with the increased presence of clouds and precipitation while the front remains hung-up. Reorganization of the synoptic wave dislodges the stationary jetstreak, and allows the front to move east with decrease coverage of showers Sunday morning into the afternoon hours. Subsidence and high pressure fills in behind the front Monday with dry and cool conditions persisting until Tuesday as anticyclonic flow pumps in from Canada. MARINE... Winds remain southwesterly overnight before gusty southerly flow develops as a low moves into the region during the daytime Friday. Gusts will strengthen to around 25 knots for nearshore zones with waves of up to 3-5 feet leading to the issuance of a Small Craft Advisory for these areas for Friday. Stable conditions will keep gusts a bit weaker over open waters. Showers are possible across the area as soon as Friday morning with a cold front moving through the region later in the day on Friday bringing showers and thunderstorms to marine zones. Mariners should be prepared for gusty winds, hail, and lightning within any thunderstorms. Beyond that, winds will become northwesterly behind the front with chances for showers and storms remaining for marine zones throughout much of the weekend. HYDROLOGY... A cold front will stall over Lower Michigan this weekend resulting in a prolonged period of showers and thunderstorms. Some showers/storms may produce heavy rainfall rates, especially Saturday afternoon and evening.Areas of one half to one inch of additional rainfall may occur Saturday and Saturday night. Minor flooding may occur, especially with areas that see repeated storms in quick succession. A quarter to a half inch of rain is possible north of M- 59 Friday evening and overnight. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...Small Craft Advisory from 8 AM to 8 PM EDT Friday for LHZ421-422- 441>443. Lake St Clair...Small Craft Advisory from 8 AM to 8 PM EDT Friday for LCZ460. Michigan waters of Lake Erie...Small Craft Advisory from 8 AM to 8 PM EDT Friday for LEZ444. && $$ AVIATION.....SC DISCUSSION...KK MARINE.......ST/MV HYDROLOGY....KK You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion...CORRECTED
National Weather Service Goodland KS
822 PM MDT Thu May 19 2022 .UPDATE... Issued at 810 PM MDT Thu May 19 2022 Red Flag Warning has been allowed to expire on time as relative humidity values have risen well above critical fire weather criteria. Wind speeds have been nudged towards the HRRR as this guidance has been nearly spot on with the timing and magnitude of the wind gusts with the FROPA. Wind gusts up to 50 mph can be expected for 1-2 hours behind the passage of the front. Snowfall amounts were also cut back a bit to account for the 65+ degree soil temperatures, as the anticipation is for any snowfall to struggle to accumulate. && .SHORT TERM...(This evening through Saturday night) Issued at 255 PM MDT Thu May 19 2022 Across the Tri State area this afternoon, skies are mainly mostly cloudy to cloudy with temperatures currently ranging from the mid 80s into the mid 90s. Warmest areas are where sunshine is pushing through the current cloud deck. Winds are southwest around 10-20 mph with some localized higher gusts. For the remainder of the afternoon, wx concerns focus on the Red Flag conditions across the region with the downslope warm and dry wind. Current cloud cover is not allowing for any detection of fires and criteria for red flag is close to/being met in some locales. Will be continuing to monitor for fires through the warning period, as area drying still despite full sunshine over the area, and could be worse if skies were totally cleared out. As the high fire danger wanes this evening, the next wx concern(s) will be the chances for rain...snow and cold temperatures for the overnight periods on Friday and Saturday. The latest GFS/NAM show and upper level shortwave in tandem with a surface front working south from the north central Rockies. This system will trigger some light rain/rain showers starting late in the day Friday and continuing into Friday night and Saturday morning. Colder air working south on northerly flow behind the front combined with cooling of the column as it precipitates, will allow for a rain to snow transition, mainly in Colorado where the coldest air will be. Despite ground temps being amply warm, a couple inches of snow is possible for western portions of our Colorado counties tapering to a few tenths the closer to the KS/NE border you get. Raised surfaces will be impacted, but most of the snow should melt nicely when in contact with the warm ground. With clouds and moisture present overnight Friday into Saturday, have held off on frost/freeze products. Overall precip will taper from east to west Saturday/Saturday night as linger moisture will bring light rain to the area. It might be just cold enough in western Kit Carson/Cheyenne counties to have a few flakes mix in with the rain before ending. Cloud cover for the overnight period will be the deciding factor for this overnight timeframe for any frost/freeze product and may need to be addressed on later shifts. For temps, a wide range for highs on Friday as colder air begins to work into the CWA. Looking for 50s in the west-northwest up to the lower 70s in the east-southeast. On Saturday, looking for mid and upper 40s in Colorado and adjacent KS/NE counties, then increasing eastward into the lower and mid 50s. Overnight lows will be below normal starting tonight with mainly 40s to around 50F east of Highway 83. By Friday night, a wide range from around 30F west, to the lower and mid 30s stretching into the Highway 25 area, then the upper 30s to lower 40s in the east. Going into Saturday night, upper 20s west to the mid and upper 30s east. With the colder overnight lows and wind for Friday and Saturday nights, wind chill readings are expected to drop into the 20s to lower 30s Friday night with coldest readings Highway 27 and west. For Saturday night, readings in the 20s east to Highway 83, then 30- 35F. .LONG TERM...(Sunday through Thursday) Issued at 225 PM MDT Thu May 19 2022 For Sunday through Tuesday...models in fairly good agreement that upper trough will move little with a series of weak waves moving through the main trough axis. This will translate to below normal temperatures and occasional chances for precipitation. Temperatures will warm enough so that snow will no longer be a concern, but may be cool enough so that with little to no instability convection will not be a concern either. So, will have high temperatures in the 50s and 60s each day with lows in the upper 30s (northeast Colorado) to the middle 40s (Hill City) each day. Wednesday and Thursday...upper trough begins to move out of the area and a ridge builds in from the west. However, models still not in very good agreement on timing of the trough moving out or evolution of the upper pattern. GFS still insists that the trough will hang around, with the operational run even cutting off a closed low centered over Oklahoma by Thursday, meanwhile the ECMWF shows a ridge axis over the central plains on Thursday. Confidence in temperatures, weather and cloud cover remain very low for these two days. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 450 PM MDT Thu May 19 2022 The main story for 00Z TAF period will be the cold front advancing towards the area resulting in an abrupt wind shift. The cold front is currently located along I-80 in the Nebraska Panhandle where gusts of 30-40 mph have been observed. A few hours of stronger winds looks likely behind the front with gusts up to 35 knots looking most likely, isolated stronger gusts are possible. Until then winds will remain from the WSW between 8-15 knots with occasional gusts approaching 15-20 knots. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...TT SHORT TERM...JN LONG TERM...024 AVIATION...TT
...Updated for 00Z Aviation Forecast Discussion...

.DISCUSSION... Issued at 319 PM CDT Thu May 19 2022 Warm and windy across the area this afternoon with southerly to southwesterly winds gusting 30-35 mph in many locations and temperatures as of 3 PM generally in the upper 80s to lower 90s. Features of note included a surface low spinning over SD with an attendant warm front stretching eastward into southern MN and cold front southwestward into western NE, along with a "punch" of dry air just ahead of the cold front. As the cold front advances into the area this evening, should see at least some shower and storm development along it, though still lots of uncertainty regarding the spatial extent and strength of any storms that do develop, with the main "deciding factor" being moisture availability. OAX 18Z observed sounding did show quite a bit of dry air through 500 mb, though surface observations did show dewpoints 5 to 10 degrees higher just east into western IA. CAM solutions show a wide range of possibilities for the forecast area this evening, from the HRRR which has consistently shown next to nothing (maybe some spotty light showers) to the NAM Nest which depicts a line of storms moving across most of the area, so confidence isn`t particularly high on how things pan out. Currently, thinking convergence along the boundary will be strong enough for storms to develop in the area with decent enough shear, mainly in the low levels, to yield some sort of storm organization. With at least initially steep low level lapse rates and linear storm structure, expect a damaging wind threat. Though with storms likely forming in the evening, and the limited moisture content leading to overall weaker storms, may be tough to get any severe winds to the surface. So to summarize, thinking we`ll see at least some storm development in the forecast area by 6-7 PM, with a line forming, pushing southeast, and possibly producing sporadic wind damage, though again, confidence is on the lower side. Behind the cold front, expect much cooler weather heading into the weekend and early next week, with highs in the 60s most days. Saturday looks to be the coolest, as highs look to struggle to get out of the 50s. On top of that, some shortwave energy will likely be sliding through the area and producing precip chances. So expect a cool and possibly rainy Saturday (we`re just the messengers). Those precip chances exit by Sunday as surface high pressure takes over and gives us a dry day. However, the next precip chances arrive for Monday into Tuesday as another shortwave trough slides through the area. Models then diverge for the remainder of the week with some guidance showing a larger scale trough digging into the central CONUS and eventually cutting off (e.g. 19.12Z GFS) and other guidance sweeping said trough quickly to the eastern CONUS and building in upper level ridging (e.g. 19.12Z ECMWF). The former solution would give us continued precip chances and cooler weather while the latter would mean the area stays largely dry and warms back up to near or above average temperatures by Wednesday. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 610 PM CDT Thu May 19 2022 Some uncertainty on storm coverage this evening as frontal boundary pushes through and winds shift to northwest then north. Expect some gusts around 30 knots or more behind the front. As for TSRA, generally have highest confidence in some storms affecting KOMA but did not include a prevailing group, just used VCTS. Will amend if storms develop and it seems like they will affect any of the sites. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...CA AVIATION...Miller