Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/18/21

Area Forecast Discussion
National Weather Service La Crosse WI
656 PM CDT Thu Jun 17 2021 .SHORT TERM...(This evening through Friday) Issued at 225 PM CDT Thu Jun 17 2021 The threat for impactful severe weather remains on tap for much of the forecast area late this afternoon into the overnight hours. As of 19Z, a poorly defined cold front stretched from Polk and St. Croix counties southwestward through the southern Twin Cities metro to south of Sioux Falls. Ahead of this baroclinic zone, a narrow corridor of rich theta-e air exists with surface dewpoints in the upper 60s to around 70 degrees and temperatures pushing 90+ degrees. Mid-level convection associated with the leading edge of an upper level impulse/jet streak have been progressing into central Minnesota and spreading cloud debris and high-based thundershowers/virga eastward across the forecast area. There is some uncertainty as to how this complex will affect the threat for surface-based convection later this afternoon. However, given the the bulk of the daytime heating haven taken place and continued southwesterly low-level theta-e advection continuing through the afternoon just ahead of the boundary, minimal modification of the near-surface airmass is expected. Impressive mid-level lapse rates coupled with the rich lower tropospheric theta-e ribbon will yield 3000-4000 J/kg of MLCAPE at peak heating just ahead of the boundary. Increasing H700-500 wind speeds ahead of the approaching upper level jet will yield 30-50 kts of effective shear in the column, plus with shear vectors oriented nearly orthogonal to the frontal slope, the initial storms should have an appreciable off-boundary motion which would promote discrete convection early on, but upscale growth into a multi-cell or linear complex is expected as we head into the evening hours. The locations impacted by convection for this event is still a bit nebulous given a number of factors, such as the strength of the EML cap, the influence of the mid-level cloud shield, and the displacement of the main jet max north of the surface front. While earlier CAM runs were strongly suggesting that discrete cells would form in the rich airmass of northern Iowa, there have been signals in the HRRR that the focus for convection may actually be in western Wisconsin and far southeast Minnesota, closer to the upper jet. Nevertheless, forecast soundings in northern Iowa still depict profiles with low inhibition by 00-02Z, so this area still bears close watching given its explosive potential. Very large hail will be a threat with any discrete cells early on given the high NCAPE values, morphing into a damaging wind threat as we head into the overnight hours. Localized flooding concerns may exist with any periods of heavy rainfall or training storms given the dry and somewhat impervious soils. The tornado potential appears more conditional based on localized enhancements to the near-surface wind field in far northeast Iowa and southwest Wisconsin where winds may remain more backed to the south and SRH values increase in the evening, but hodographs within the inflow layer would support streamwise vorticity ingestion and possibly torndogenesis. The front sags southward through the overnight hours, taking the convection southward with it. The threat for severe weather should wane after 06Z and storms should exit the southern forecast area by 12Z. With upper level forcing lifting out of the region, the front should lay out and linger over central Iowa and Illinois during the day on Friday, but any additional storms should stay south of the area. .LONG TERM...(Friday night through Thursday) Issued at 225 PM CDT Thu Jun 17 2021 Look for mostly dry conditions into the weekend with increasing CAA slowly but steadily driving temperatures downward. Highs by Saturday fall into the upper 70s to low 80s with surface high pressure firmly in control. The next upstream wave descends into the northern CONUS on Sunday, lifting the near surface baroclinic zone back northward and bringing with it the threat for rain/storms during the day. A shot of colder Canadian air arrives for the first half of the week, a welcome change from the record hot start we have had to the month of June. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 645 PM CDT Thu Jun 17 2021 Thunderstorms will continue to be in the vicinity of the KRST/KLSE sites until the front moves through the area later tonight; 04-06Z. Some of the storms may be strong to severe with large hail and damaging winds. The storms are initially isolated, but as the low level jet increases should consolidate and drop southeast of the area. Due to the isolated nature will metwatch as needed to include any of the higher end winds and mention of hail. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Skow LONG TERM...Skow AVIATION...Zapotocny
Area Forecast Discussion
National Weather Service Denver/Boulder CO
800 PM MDT Thu Jun 17 2021 .UPDATE... Issued at 800 PM MDT Thu Jun 17 2021 High based showers and thunderstorms have progressed eastward onto the eastern plains. Gusty winds have been the main feature with this activity with gusts up to 50 mph. Doesn`t appear much rain occurred. The showers and thunderstorms will come to an end by midnight as the airmass stabilizes. Going forecast on track with no major changes planned. && .SHORT TERM...(This evening through Friday) Issued at 300 PM MDT Thu Jun 17 2021 A strong ridge over the Four Corners region continues to maintain its strength with record highs reported across much of the Desert Southwest. Denver hit 100 degrees for the third day in a row. Showers and storms have formed mainly over South Park and the Palmer Divide while high level clouds are limiting storm development farther north. Localized microbursts are possible underneath the stronger storms as soundings show a well-mixed boundary layer up above 500 mb. DCAPE is up to 1,700 j/kg which would support winds up to 55 mph. Some of these showers and storms will continue overnight tonight across the eastern plains. The HRRR seems to be trying to resolve a heat burst or two on a couple runs which is unique. The conditions seem to be prime for heat burst development due to the inverted-V soundings, very hot daytime temperatures, and very high-based showers so it seems believable. Winds could reach 55 mph if a heat burst or dry microburst were to occur. Otherwise, low temperatures will be near the warmest on record with lows in the mid to upper 60s across the plains. The aforementioned Four Corners ridge will weaken a bit on Friday as there will be 500 mb height falls over our CWA. A weak cold front will move across our forecast area tomorrow morning with northeasterly winds bringing in better moisture and cooler temperatures. The high tomorrow will be around 90 in Denver. Models are struggling to come into agreement as to how far west the moisture will get and whether or not it will mix out tomorrow. The NAM and NAM Nest have the moisture getting farther west (up to the foothills) than the HRRR and GFS (stays east of DIA) which would mean higher instability values and a better likelihood of storms over the foothills and I-25 corridor. I tend to think the NAM solutions will be closer to verification so I increased the PoPs across the foothills and I-25 corridor tomorrow afternoon. There will be enough instability (around 1,000 j/kg of mixed layer CAPE) for storms to become severe although the surface to 6km wind shear will be lacking (around 30 knots). An isolated severe storm or two is expected with hail and wind gusts being the primary threats. .LONG TERM...(Friday night through Thursday) Issued at 300 PM MDT Thu Jun 17 2021 Closer to seasonal temperatures are expected through the early part of next week. The center of the upper level ridge will remain over central AZ through the weekend. On Saturday, a relatively weak westerly flow aloft will be over northern CO, with a moist southeasterly winds at the surface. Surface dewpoints 55-60F in the morning mixes out in the afternoon, but sufficient moisture over the far northeast plains, around 50F for one or two marginally severe thunderstorms with GFS forecast soundings indicating surface based CAPES over 1000 j/kg. Less subsidence in the mid/upper levels with the ridge shifted over the Desert Southwest. 500 mb heights still around 585 dm over northern CO Saturday with the highs around 90F. Elsewhere, generally gusty winds should be the main threat from the storms. On Sunday, the flow aloft will increase over northern CO. The models show weak qg ascent in the mid and upper levels ahead of a short wave trough passing out of the northern Rockies and across WY. A cold front associated with this system will push across the forecast area Sunday morning, with gusty north to northwest winds in the morning transitioning to northeast in the afternoon. The models indicate the nose of a 100 kt jet max brushing the northern border around 00z Monday. This will certainly improve the storm motions of any developing storms, but could also elevate the threat of severe storms depending on the timing of the cold front. The ECMWF is slower than the GFS with this next system. The bottom line, Monday will significantly cooler and wetter from the Front Range eastward across the northeast plains. The threat of flooding in the burn areas will be elevated, but increased stability may translate more to steady stratiform rain vs convective showers. By the middle of next week, it`s back to the 90s with a broad ridge && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 800 PM MDT Thu Jun 17 2021 Southerly winds are expected to prevail the rest of the night. Just a slight chance of an additional wind shift from the convection off to the east. A cold front will move through Friday morning bringing northeast winds behind it. There will be a chance for showers and thunderstorms after 21Z Friday. Outflow winds gusting to 40 knots will be the main threat. && .FIRE WEATHER... Issued at 300 PM MDT Thu Jun 17 2021 Most areas will see higher moisture levels on Friday meaning relative humidity will only bottom out around 25 percent. This will keep fire danger on the lower side. The exception will be North Park and the surrounding terrain that will have less moisture as relative humidity will drop to the low teens. There will be elevated fire danger across that area as wind gusts will reach 25 mph. && .HYDROLOGY... Issued at 300 PM MDT Thu Jun 17 2021 Moisture will increase on Friday behind a cold front that moves through the area. Some storms are expected to form over the burn areas which could pose a threat for flooding. This threat is rather limited though as precipitable water values are on the lower side. A modest increase in thunderstorm activity is expected for Saturday through Monday, and more moisture will be available as well. Storms are expected to be moving, but there could be enough rain with the strongest storms to cause minor flooding in the new burn areas. This low risk of flooding will continue through Monday, then drier conditions will reduce the risk after that. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Meier SHORT TERM...Danielson LONG TERM...Cooper AVIATION...Meier FIRE WEATHER...Danielson HYDROLOGY...Cooper
Area Forecast Discussion
National Weather Service Des Moines IA
723 PM CDT Thu Jun 17 2021 .DISCUSSION.../Tonight through Thursday/ Issued at 401 PM CDT Thu Jun 17 2021 Tonight into Friday...Elevated convection across northern Iowa looks to continue to push eastward and although not severe attm, there is the potential for intensification as they trickle east. Certainly the threat of hail and winds with the elevated nature of these storms and not concerned with the tornadic activity due to the LCLs of 2500-3000m. Cloud bases are AOA 10kft and convection should continue to fester north of Highway 20. The 17.18z HRRR is not handling the current convection attm, but the FV3 and NAM Nest has some hint of the current radar trends. The cap seems to be strong enough (700mb temps of 12-14C) to keep these storms below severe attm, but the latest convection has helped break the cap as well cap does weakening further east. Plenty of CAPE present, surface and MLCAPE, and the effective shear continues to trend upward and the DCAPE around 1400 J/kg per latest SPC Mesoanalysis. Lacking significant deep moisture but certainly sufficient moisture available and would not be surprised if a couple of storms become severe around the Interstate 35 corridor north of Highway 20. This is handled with the WW276 until 03z. Next round looks to be late tonight into Friday morning along the nose of the LLJ and surface boundary draped over southern MN into northwest IA. The majority of the CAMs keep the convection east of the forecast area, or delay the storms until past 12z Friday, other than the latest NAM Nest. Seems more likely solution with the LLJ increasing and the 850mb front sagging southward and covering much of the central part of the forecast area. Deep layer shear is sufficient to keep storms going, but the CAPE dwindles through 12z Friday. Low confidence with severe threat but a few storms should be around central Iowa by the morning commute. Saturday through Monday...Surface high pressure builds into the region Friday night into Saturday providing a cool and even less humid airmass. Decent shortwave and surface low track across the Central Plains into Corn Belt on Sunday. Confidence is increasing with some convection over central to northern Iowa by Sunday morning into the afternoon as models are in good agreement with timing and location of system. Sharp cold front through the region Sunday night providing a much needed cool down by Monday and Tuesday. Cold night Monday night with lows into the 40s and 50s. No significant system next week to help with drought conditions. && .AVIATION.../For the 00Z TAFS through 00Z Friday evening/ Issued at 717 PM CDT Thu Jun 17 2021 Main concern initially will be convection at N IA terminals along a boundary that sags south after 02z. Still some uncertainty at the extent of the coverage, but for now confidence is highest at KMCW and KALO, so kept TEMPO going there. Confidence is less at KFOD, so VCTS will suffice. Going to take storms longer to sag south along the boundary, so have added VCTS to KDSM and KOTM after 12z to reflect this possibility. Another round of storms a good bet across southern Iowa just beyond this TAF cycle, mainly impacting KOTM. && .DMX WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM CDT this evening for IAZ023-024-033>036- 044>050-057>062-070>075-081>086-092>097. && $$ DISCUSSION...Podrazik AVIATION...Hahn
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1154 PM EDT Thu Jun 17 2021 .AVIATION... Convection west of the region late this evening will work east, southeast into the area overnight into early Friday morning as strong elevated warm air advection regime spreads into the lower Great Lakes. A wedge of relatively unstable air will precede this convection so will maintain tsras in the forecast with a TEMPO around dawn. Activity later in the forecast in advance of a cold front is in question given the expected influence of this early day convective system. Given 00z HiRes model trends, it appears there will be a window for activity to fire before shift southeast so will include another PROB30 group for the I-94 terminals. Main period of showers with embedded thunder will be from 08z-09z through 13z-14z with the next round of scattered convection somewhere in the 18z-22z time frame. Southwest winds will persist through the forecast, veering to a more west direction late Friday with the cold front. For DTW...00z guidance still suggests showers with some embedded thunder seem likely in the 10z-14z time frame. This activity is already underway over the upper midwest and expect convection to track into the area late tonight within zone of warm air advection. Will include PROB30 group for additional convection in the mid afternoon, but confidence in this period is much lower. .DTW THRESHOLD PROBABILITIES... * Low to medium in thunderstorms with cigs aob 5000 feet impacting the terminal early Friday morning. Low Friday afternoon as new development may fire near/south of the terminal. && .PREV DISCUSSION... Issued at 356 PM EDT Thu Jun 17 2021 DISCUSSION... A dry and warm is in place this afternoon under a deamplifying ridge that will be suppressed further east through remainder of the day. Temperatures of around 16-17C at 850 mb are contributing to the afternoon temperatures that have climbed into the 80s for most of southeast Michigan. Dry weather conditions with the elevated fire danger continue through this evening before an abrupt change arrives tonight. Flow tonight becomes more zonal in the mid and upper levels after the ridge is flattened with the help of a shortwave moving into the Hudson Bay. This will usher in an impressive theta-e plume to our west into Lower Michigan tonight through early tomorrow morning with the dry air being replaced by PWATs greater than 1.50 inches. An MCS is expected develop within this theta-e plume and track through Wisconsin/far northern IL tonight. The leading edge of this MCS should arrive to west/southwest portions of southeast Michigan after midnight tonight with bulk of rainfall occuring between 07-15Z. The 12Z suite of models still leaves a bit of uncertainty in regards to how far north convection will be as MCS moves E-SE into southeast Michigan, the HRRR being the more aggressive with the further north solution. The other scenario and slightly better consensus is for the bulk of better convection to move across west/southwest portions of the CWA. It does appear that the intensity of this activity will be weakening as it outruns the corridor of greater instability. Though, MUCAPEs of a few hundred j/kg with enough shear, jet support, and 6-7 C/km mid level lapse rates will sustain convection with embedded thunderstorms as it rolls through. Gusty winds will be possible as low level winds increase to 30-35 knots. Rainfall amounts with this system also dependent on MCS track. QPF amounts across the majority of the CWA should be well below a half inch. Though, amounts may need to be adjusted upward if northerly track looks like it will play out as advertised by the Euro and HRRR. The track and speed of the MCS tonight remains important for how things play out Friday. The best forcing appears likely to be south of Michigan associated with the modified convective boundary across Indiana and Ohio. Greater forcing from the north with the Ontario shortwave is also lagging in arrival ahead of a frontal boundary. The other limiting factor to severe weather development is presence of a capping inversion up to around 800 mb. This would effectively suppress deep convection given the weaker forcing if it holds through much of the day. There will be plenty of shear present with 40+ knots from 0-6 km with lapse rates again slightly greater 6 C/km. MLCAPE values during the afternoon build up to at least 1500-2000 J/kg with up to around 3000 J/kg near the border. Thus, the set up for tomorrow will be conditional for severe weather. The question is if there will be enough forcing to take advantage of the favorable environment or if the cap can erode enough for weak shortwaves to generate convection. Several Hi-res models for Friday afternoon are showing limited convection in our area. At the moment, the best forcing looks to our south and north. Be sure to stay up to date with the forecast as adjustments are still likely for tomorrow afternoon and evening. A trailing weak shortwave swings across the state on Saturday atop a stationary boundary while the larger shortwave trough moves from Ontario into Quebec. Expecting most areas to stay dry, but there remains at least a low chance for some weak convection. The overall airmass remains warm over the weekend with some lingering moisture. High temperatures over the weekend are forecast to stay in the 80s. The next appreciable chance for showers and thunderstorms may come Sunday night/Monday ahead of cold front tracking through the region while troughing deepens across the central CONUS. MARINE... South/southwesterly flow continues to increase through the evening, with gusts topping out around 20 kts across northern Lake Huron, as a tightened pressure gradient migrates southeast through the Great Lakes ahead of approaching sfc trough. More widespread gusts of 20+ kts expected tomorrow in response to enhanced flow aloft and cold frontal passage. Given uncertainty in timing/stability over the lakes and marginal gust potential, will continue to monitor advisory potential for the next forecast update. Approaching weather system to also produce two rounds of shower/thunderstorm activity: tomorrow morning and again in the afternoon/evening with main hazards being lightning, brief periods of gusty winds/enhanced waves, and heavy downpours. Winds behind the cold front shift northwest late Friday- Saturday, with dry conditions expected to prevail for the weekend as high pressure returns. HYDROLOGY... An area of showers and thunderstorms will be moving across central/lower Michigan late tonight through early Friday morning. A high degree of moisture with PWATs greater than 1.50 inches will accompany this system. This will bring potential for some locally heavy rainfall with any embedded stronger thunderstorms. There is still some uncertainty in the track of this system and where heaviest rainfall occurs. Basin average rainfall amounts will range generally around a quarter inch with higher amounts towards Lenawee County. If track of MCS is further north, amounts will need to be increased slightly up towards the I-69 corridor. No significant flooding concerns anticipated, but any localized higher amounts associated with embedded with thunderstorms may lead to some minor flooding of low lying and urban areas. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...Small Craft Advisory from 4 AM to 4 PM EDT Friday for LHZ421-422- 441>443. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....DG DISCUSSION...AA MARINE.......MV HYDROLOGY....AA You can obtain your latest National Weather Service forecasts online at
National Weather Service Wilmington OH
1155 PM EDT Thu Jun 17 2021 .SYNOPSIS... A decaying system will be approaching late in the overnight and into the early morning hours on Friday. Severe thunderstorms will develop during the late afternoon and into the evening hours on Friday. Heavy rainfall will also be possible. Thunderstorm activity and the potential for severe weather will again be possible on Saturday as the boundary remains in place across the region. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Some storms firing in west central IN/east central IL ahead of the line of decaying showers over nrn IL/srn LMich. Took this and a few very minor returns over nw IN and blended them into the 12z forecast to account for movement, but no models were showing any kind of initiation in this section at all tonight, so this appears to be a wildcard in play that will likely affect the forecast updates tonight, especially if the CAMs take a while to see this and adjust. Low temperatures overnight are expected to drop down into the middle 50s to the middle 60s. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... An active weather pattern will be in place for Friday into Friday night. A decaying MCS will continue to move into northern portions of the region during the morning hours. There are some model solutions that bring this feature further south and this would have implications for afternoon placement of convective development. At this point in time have a slight chance to chance of precipitation for locations generally north of the Ohio River with likely precipitation generally north of Interstate 70. This feature will then likely lay out a boundary for convective development during the late afternoon and into the evening hours. Winds will pick up for the afternoon hours and have wind gusts upwards of around 25 to 30 mph outside of thunderstorms. There are some concerning signals for a higher end damaging wind event late Friday afternoon into Friday night. CIPS analogs also are supportive of this and SPC has a large portion of the region in an enhanced risk. Given shear profiles there is also at least some tornadic and hail potential as well. Added severe wording into the forecast Friday night the flow becomes more west-east oriented. With this flow orientation there will be flooding concerns as well. A flood watch will be needed in the future, however held off for now to try to fine tune where the axis of heaviest rainfall will be. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Long term period begins with potential storm complex in the south as the upper energy heads east along a mostly stationary front. Guidance varies as to how long the convection persists, with the 3-km NAM on the drier side and the HRRR keeping convection going until it exits into southeast Ohio late Saturday morning. While warm muggy conditions continue Saturday into Sunday, forcing looks to be rather weak as the frontal boundary dissipates. Expect PoPs to decrease considerably during this time with isolated diurnal convection remaining in the grids due to conditional instability. High temperatures will peak in the mid to upper 80s each day, with lows in the upper 60s. For Monday, a stronger, more progressive cold front dives southeast through the region. Uncertainty is high as far as timing the front. ECMWF and its ensemble are slower, with FROPA occurring Tuesday morning, and the GFS system quicker with FROPA on Monday evening. Uncertainty is amplified by the slow progression of tropical remnants moving through the southeast United States Sunday into Monday. Despite uncertainty, there is certainly some concern about strong to severe storms firing along and ahead of the front beginning Monday afternoon into the evening. Behind the front, decreasing clouds and cooler, drier air arrives with surface high pressure starting to build in after noon on Tuesday. In fact, model blend has dewpoints dropping into the upper 40s to lower 50s Tuesday night and Wednesday. Highs stay in the low to mid 70s. The high shifts to the east on Thursday with max temperatures returning to near 80. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... Southerly winds will be 5-8kt this overnight period with the exception of Lunken which may see some few vsby restrictions towards daybreak and will decouple and go calm in the next 2-3 hours. Tomorrow will see this south-southwest wind increase to 12-15kt in the morning and begin gusting to 25kt or so by noon, becoming a little stronger in the late day. Guidance on timing of rain still runs a wide variety of spectrums in how they play out tomorrow`s forecast. Near as I am able to discern, activity will be north of the TAF sites through 18z but there are indications that an outflow boundary from upstream storms may cross the northern sections of the CWA and could be enough to initiate some few showers ahead of the main body of storms that are still expected to remain to the north of the CWA and TAF sites through this time. After 18z, storms will likely be knocking on the door to west central Ohio and could skirt KDAY. Did not add vcsh during this time until 20z at CMH, but do have VCTS at DAY/CMH/LCK starting at 22z, and at 05z for the extended CVG TAF. Mechanisms are in place to see significant storms in the evening and overnight Friday along the I-70 corridor and then dropping southward. Kept VFR conditions over the TAF sites with the exception of the last 2 hours in the CMH forecast. Hopefully the model depictions will begin to coalesce into one or two better probability scenarios tonight that may present more of an opportunity to include a better timing and stronger sense of area affected, at least to begin the showers and storms. While chances of rain at ILN and southward aren`t high enough to include for tomorrow afternoon, they aren`t low enough to discount the possibility entirely. Evolving forecast will continue to hone in on what is the most likely tomorrow as time progresses. .OUTLOOK...Thunderstorms are possible through Saturday and again on Monday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Novak NEAR TERM...Franks SHORT TERM...Novak LONG TERM...Hogue AVIATION...Franks
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
319 PM CDT Thu Jun 17 2021 .SHORT TERM...(This evening through Friday night) Issued at 317 PM CDT Thu Jun 17 2021 Weak showers with very isolated thunder have been making attempts at getting some precipitation to the ground, but we have been pretty strongly capped, and they are encountering drier air as they move east. A weak cold front is passing through the Twin Cities as I write, but the main change with the FROPA is a shift in the winds to the northwest. The front will continue to slowly move to the southeast through the afternoon and evening. A surge of instability will move northeastward this afternoon into southern Minnesota as the front moves into these areas. The front should erode the CIN along the front late this afternoon and with bulk shear values 40-50 kts and steep lapse rates there could be explosive convective growth, but the HRRR keeps pushing back the storm initiation and it looks like the best chance for strong to severe storms will be on the periphery of our forecast area along I-90 and southern portions of west central Wisconsin. The SPC day 1 outlook has southeast Minnesota in an enhanced risk for severe storms with Slights and Marginals extending north of there, with the marginal risk just south of the Twin Cities Metro area. The main threats are large hail and damaging winds, but a tornado can not be ruled out. Any storms that do develop in our area should move southeast quickly. There won`t be much change in temperature with the this FROPA until later tomorrow when a stronger front comes through the area. Brisk northwest winds will gust to 25-30 MPH behind the front before relaxing overnight. These gusty winds and RH values falling into the teens and 20s will lead to critical fire weather conditions which may require a headline. Behind this secondary front, temperatures tomorrow night will be very comfortable for sleeping with low temperatures falling into the 50s with the CAA. .LONG TERM...(Saturday through Thursday) Issued at 317 PM CDT Thu Jun 17 2021 Saturday should be a very nice day as the forecast has highs in the upper 70s to mid 80s, clear skies, and light westerly winds. Low relative humidities signal that elevated fire weather conditions will be possible, especially in western MN where RHs of 20-25% are forecast. Precipitation chances begin late Saturday night as an amplifying upper-level trough approaches from the west. Showers and thunderstorms will develop across western MN early Sunday morning along a warm front. This activity will spread and travel eastward during Sunday as the open wave system matures. Redevelopment of showers and thunderstorms is possible Sunday afternoon and evening in eastern MN/western WI ahead of the approaching cold front. However, warm sector recovery is highly uncertain at this time due to the likelihood of convective debris over the region. Additionally, differences between models exist in how much the trough amplifies while crossing the Northern Plains: the NAM and GFS showing a much more amplified, narrower trough while the ECMWF and GEM`s troughs are broader and flatter. Thus, the timing and amount of synoptic-scale forcing is also rather uncertain with the American model suite being the most aggresive. Thus, while there is a chance for some stronger thunderstorms later Sunday, too much uncertainty remains to dig into the finer details. A cool down is forecast Monday into Tuesday as northwesterly flow moves over the Northern Plains proceeding the trough. Have adjusted both Monday and Tuesday`s highs downward as guidance has trended much cooler than the NBM over the last several runs. Also, the very warm temperatures as of late means that the NBM is likely biased too warm for this brief cool spell. NBM`s temperatures for early next week have been slowly decreasing with time but have opted to "cut to the chase" and not wait for the likely inevitable. Currently have highs in the low to mid 60s on Monday while Tuesday is in the upper 60s to lower 70s. Also, Monday night`s lows could be quite chilly with our northern counties dropping to near 40. Otherwise, the workweek next week looks mostly dry as slight ridging tries to work its way into the central CONUS. Temperatures are forecast to moderate back into at least the 80s by Thursday. && .AVIATION...(For the 12Z TAFS through 12Z Friday morning) Issued at 540 AM CDT Thu Jun 17 2021 Thunderstorm development will be possible this afternoon and evening at southern/eastern sites as a cold front sags southeast across the area. Otherwise, VFR conditions will prevail with scattered to broken mid and high clouds. KMSP...Thunderstorms will quite possibly develop south and east of KMSP, but there was still enough concern to warrant a Prob30 group for this afternoon. /OUTLOOK FOR KMSP/ Fri...VFR. Wind WNW 15-20G30 kts. Sat...VFR. Wind NW 5 kts. Sun...VFR, chc MVFR. -TSRA likely. Wind SE becoming NW 10-15G25 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ SHORT TERM...CEO LONG TERM...CTG AVIATION...LS
Area Forecast Discussion
National Weather Service Paducah KY
603 PM CDT Thu Jun 17 2021 .SHORT TERM...(Tonight through Saturday night) Issued at 233 PM CDT Thu Jun 17 2021 The latest HRRR is dry for the rest of the afternoon and evening out in southeast Missouri. After our rogue strong storm over in Carter and Ripley counties this morning, satellite shows a scarcity of cumulus over there with an obvious convergence zone west of our area. Will keep a very small PoP over there just in case more rogueness develops. Upper-level energy will spread east southeast into the Great Lakes tonight into Friday, and that will suppress the upper ridge over the Quad State. With the associated surface boundary remaining well to our north Friday, we will be heading for a bad hair day over most of the region. Temperatures will climb into the mid and upper 90s with the warmest air expected in the northwest. Humidity will also be on the increase with the highest dewpoints (low-mid 70s) also in the northwest. This will lead to heat indices reaching 100 by 11 AM and maxing out at 105-109 over at least the northern two rows of counties in southern Illinois as well as Perry county Missouri eastward to Williamson County Illinois. Will be issuing a Heat Advisory for those areas with this forecast. The Advisory may need to be expanded into southwest Indiana, but will let the midshift take another look at that. In addition to the heat advisory, we will be right near Lake Wind Advisory criteria across the northern half of the area. Will give the winds a mention in the HWO, but will hold off on an Advisory at this time. The 12Z HREF keeps convection Friday night to our north, with the exception of the ARW which does bring some convection into southwest Indiana overnight. Will have a swath of 20-30% PoPs along the I-64 corridor mainly overnight just in case. Certainly could not rule out some strong winds with any storms that do reach the area. By Saturday, the active surface boundary may be close enough to our area to allow renewed convection to make it into southern Illinois and the Tri State. As a result will have 50% PoPs in the far northeast and bring slight chances all the way south to KCGI and KPAH in the afternoon and evening. Temperatures will not be quite as warm as Friday and it appears that the moisture will mix out a bit more as well, but 2000-2500 J/kg of surface-based CAPE will be possible. Expect a few strong updrafts, but mostly a pulsy mode. Cannot rule out some isolated damaging winds, but lightning and locally heavy rainfall should be the primary concerns. Saturday night will be mostly dry as our attention turns back to the south with the tropics on our minds. .LONG TERM...(Sunday through Thursday) Issued at 233 PM CDT Thu Jun 17 2021 The developing tropical system in the Gulf will be the main weather influence Sunday. Pre-genesis tropical cyclones are notoriously difficult to model and there is quite a bit of spread amongst the operational and ensemble guidance in the placement of this system. On Sunday morning guidance varies in placement from central MS to central GA. The same idea applies to our weather as the previous packages with a more westward final solution being rainier and a more eastward destination drier. For now, continued mainly afternoon slight chance/chance shower and thunderstorm pops in line with NBM but uncertainty remains high. Monday still appears to be the best chance for rain as an upper trough pushes a fairly strong cold front into the area. GFS/GEFS seems more amplified and progressive with the trough and faster with the front, while the ECMWF is a bit slower. Kept likely shower/thunderstorm chances for the day Monday and into Monday night and kept a lingering chance for showers/rain Tuesday morning in the east owing to the slower ECMWF solution. The synoptic pattern will be at least somewhat favorable for a strong to severe storm or two but the finer details of this threat or lackthereof will likely become clearer in the coming days. Locally heavy rainfall also appears possible although net QPF appears to be trending downward as column moisture decreases a bit from past guidance. Behind the front on Tuesday looks pretty spectacular, with highs in the upper 70s and lows in the mid 50s amid mostly sunny skies. Wednesday will likely be warmer and slightly more humid as ridging slides eastward. Introduced shower/thunder chances again on Thursday as low level winds increase from the south ahead of the next upper disturbance moving through the plains. && .AVIATION... Issued at 603 PM CDT Thu Jun 17 2021 VFR conditions, with generally unrestricted ceilings and visibilities should dominate the WFO PAH TAF locations for the 00z Friday forecast. Cannot rule out some scattered to locally broken mid- level clouds developing between 11z-15z Friday over the KPAH/KEVV/KOWB TAF sites, as moisture near 10kft agl is lifted along the mid-upper level shear axis of an west to east oriented ridge. This ridge becomes more suppressed further south across the WFO PAH TAF sites during the late morning and early afternoon on Friday, in advance of a shortwave moving east across the area. At this point in time, have low confidence in seeing anything other than VFR conditions through the forecast period. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Heat Advisory from 1 PM to 7 PM CDT Friday for ILZ075>078- 080>085. MO...Heat Advisory from 1 PM to 7 PM CDT Friday for MOZ076. IN...None. KY...None. && $$ SHORT TERM...DRS LONG TERM...99 AVIATION...Smith
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
729 PM EDT Thu Jun 17 2021 .AVIATION... Prevailing VFR conditions will return after RA and low clouds move away from TPA/PIE terminals over the next couple of hours. Southeast winds by late morning, shifting onshore at coastal TAF sites courtesy of the west coast sea breeze. VCTS introduced by 17Z-20Z tomorrow afternoon. && .Prev Discussion... /issued 624 PM EDT Thu Jun 17 2021/ UPDATE... Showers with the occasional embedded thunderstorm continues to gradually push northward this evening with the bulk of rainfall now north of Tampa - across Tarpon Springs and Brooksville. This convective activity is propagating along an outflow boundary being driven north with the help of low-level southerly flow around 10 knots. RAP analyses suggests MLCAPE of 800-1200 J/kg along and north of I-4 will support the reformation of showers (and perhaps a thunderstorm) as we head through the remainder of the evening hours. Farther south, light stratiform rain remains over Lee county and is slowly dissipating across the area. This evening`s updates consist of PoP adjustments through the next 9 or so hours to account for latest radar trend and mesoanalysis... The remainder of the forecast remains on track. In other news, NHC has began issuing advisories on Potential Tropical Cyclone 3 in the SW Gulf of Mexico this afternoon. This disturbance is expected to become a Depression or Storm as it moves towards the LA coast during the next couple of days. No direct impacts are anticipated across West Central and Southwest FL. && .Preliminary Point Temps/PoPs... TPA 75 90 76 90 / 20 40 10 30 FMY 74 91 74 93 / 30 40 0 30 GIF 73 90 73 93 / 30 40 10 40 SRQ 74 89 74 92 / 10 40 10 20 BKV 70 90 72 92 / 40 40 10 40 SPG 77 89 77 90 / 20 40 10 30 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ Update/Aviation...Norman Decision Support/Upper Air...Oglesby
Area Forecast Discussion
National Weather Service Las Vegas NV
146 PM PDT Thu Jun 17 2021 .SYNOPSIS... Dangerous heat will continue through the weekend as temperatures continue to approach record values. Early next week temperatures will begin to decrease but are still expected to remain above normal. Isolated thunderstorms producing dry lightning and strong winds will be possible on Friday. && .SHORT TERM...Today through Saturday. The heat wave continues with another few days of well above normal temperatures challenging records in many areas through early next week. A cloud shield this morning helped insulate us overnight with a morning low at McCarran of 90 degrees. This may limit us from approaching all-time record highs as we have the past couple of days. With this being said, it will still be very hot with triple digit temperatures in many locations. No changes are needed to the Excessive Heat products which now go through Sunday. The clouds will lead us to the other weather topic for today and tomorrow which is the potential for high based showers and storms with an influx of mid-level moisture. Currently, there are light radar returns over much of the area as a weak wave rotates around the the high which is still centered to the east over the Four Corners region. Today instability is pretty much limited to Inyo County and the Sierra but a few moderate updrafts are being indicated over southern Clark County and central Mohave County later on today on the last few HRRR runs. Showers and any isolated storms will be very capable of producing strong outflow winds. Even light activity this morning has already seen a measured gust of 50 mph out of a weak shower over Kingman. This is further supported by DCAPE values of 1000-2000 J/kg and very dry low levels indicated on this mornings sounding. Activity should decrease this evening with potential for pre-sunrise showers over southeast California and Esmeralda and Nye counties. Instability will be more widespread on Friday across much of southern Nevada and northeast Arizona which will support potential for convective development Friday afternoon. Threats remain similar to today in dry lightning, strong outflow winds, and lofted dust. By Saturday, the ridge shifts southwestward cutting off our southeast flow which will limit chances for any shower or storm activity but continue the very hot temperatures across the region. .LONG TERM...Sunday through Wednesday. Sunday`s high temperatures are expected to be a few degrees below highs on Saturday which should bring an end to record challenges for the time being. With that said, Sunday morning low temperatures will still be very warm and provide little relief while the slightly cooler daytime temperatures on Sunday will remain around 10 degrees above normal. Since heat risk changes little Sunday and will remain quite elevated, went ahead and extended all heat products through Sunday evening. A cooling trend brings more tolerable temperatures to the area Monday through Wednesday even though summer officially begins on Monday. Any moisture that was lingering around the area to begin the weekend is flushed out Sunday with very dry conditions forecast through Wednesday. Looking further out, the Climate Prediction Center forecasts the probability of seeing above normal temperatures across the NWS Las Vegas CWA in the 8-14 day period at 40-60 percent. && .FIRE WEATHER... Heat wave continues through early next week with the addition of isolated, dry thunderstorms today and tomorrow. These storms will also be capable of producing strong, erratic wind gusts in and around the area up to near 50 mph. The higher terrain will see more favorable chances for this activity both days with Friday being a slightly more active day than today. As a result, went ahead and upgraded the Fire Weather Watch to a Red Flag Warning with the addition of Fire Weather Zone 227 in eastern Inyo County. RH values will drop below critical values each afternoon through early next week. && .CLIMATE...Listed below are a few climate locations showing both the record high maximum and high minimum temperature for each location and the year the record was last set for this Wednesday, Thursday and Friday. LOCATION THU-JUNE 17 FRI-JUNE 18SAT-JUNE 19 (HIGH MAX) Record(year) Record(year)Record(year) Las Vegas NV 113(1940) 115(1940) 114(1940) Bishop CA 104(2017) 107(1985) 107(2015) Barstow CA 110(2017) 112(1985) 115(2017) Needles CA 120(1917) 119(2017) 123(2017) Kingman AZ 108(1917) 109(2017) 111(2017) Desert Rock NV 106(2017) 108(2017) 110(2017) Death Valley CA 122(1917) 124(2017) 125(2017) Laughlin NV* 113(2017) 117(2015) 117(2017) Lake Havasu City AZ* 115(1985) 115(1985) 117(2017) * Not climate sites, but state temperature record holders. LOCATION THU-JUNE 17 FRI-JUNE 18SAT-JUNE 19 (HIGH MIN) Record(year) Record(year)Record(year) Las Vegas NV 87(2008) 86(2017) 88(2017) Bishop CA 65(2002) 69(2017) 67(2017) Barstow CA 78(1971) 79(1971) 79(2017) Needles CA 88(2000) 90(1988) 87(2017) Kingman AZ 79(1949) 73(2000) 75(1945) && .AVIATION...For McCarran...Persistence wind forecast for the rest of this afternoon so sticking with an easterly component up to 10 kts. However, any passing area of virga could bring a sudden shift and gustiness to the wind. Confidence in any of those scenarios is low so did not mention in the forecast. Typical down valley wind up to 8 kts will develop overnight, although there is some indication that a more northwesterly wind may develop after midnight. Looking at an easterly wind up to 10 kts developing again Friday. Any isolated shower or thunderstorm over the higher terrain Friday could bring higher gusts to the valley. No significant clouds expected below 12 kft. Temperatures will remain in the 113 to 115 range over the next few days with temperatures exceeding 100 by 11 AM. For the rest of southern Nevada, northwest Arizona and southeast California...Outside of any convective influence wind at terminal sites the rest of this afternoon should be light and variable. Any nearby shower or thunderstorm could bring on a sudden shift and gustiness. Look for typical downvalley winds to develop overnight with speeds less than 10 kts. The exception will be around KDAG where sustained speeds will be 10-15 kts. Typical afternoon winds expected across the region Friday, but any isolated shower or thunderstorm over the higher terrain Friday could bring higher gusts to a terminal. No significant clouds expected below 12 kft. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM/FIRE WEATHER...Guillet LONG TERM...Salmen AVIATION...Pierce For more forecast information...see us on our webpage: or follow us on Facebook and Twitter