Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/19/21

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
715 PM CDT Fri Jun 18 2021 .AVIATION... For the 00Z TAFs, showers and thunderstorms over southeast Colorado and northeast New Mexico are forecast to remain to the west of the terminal sites this evening. Some high level clouds are also expected during this forecast cycle. Overall, VFR conditions will prevail at KGUY, KDHT, and KAMA through late Saturday afternoon. 02 && .PREV DISCUSSION... /Issued 239 PM CDT Fri Jun 18 2021/ DISCUSSION...Tonight through Thursday... High pressure remains over the Desert Southwest this afternoon with anticyclonic flow noted over the area on latest WV imagery. There has been a tendency for decreasing 500mb heights over the Panhandles as the upper high slowly weakens and shifts more over AZ. A more progressive trough pattern continues across Canada and portions of the northern CONUS, and this will help break the high down further going into Saturday, allowing for more of a westerly component to the upper flow over portions of the southern plains. A few storms were forming over the southern Rocky Mountains this afternoon, but the latest surface observations and upper features suggest these will have a tough time making very far off the higher elevation. A stray storm might try to push into the far western OK Panhandle late this evening in association with a weak 500mb vort max, but the lack of instability and moisture in this area will likely result in storm decay prior to arrival. A left over outflow boundary may push into the northwest zones and stall overnight, possibly setting up as a lifting mechanism for Saturday evening. With the added westerly component to the upper level winds by tomorrow evening, a more notable lee surface trough can be expected over the Raton Mesa. Convergence along this feature should help initiation of storms in the late afternoon as a weak shortwave trough rides over the ridge across the southern Rocky Mountains. As storms move easterly towards the northwest combined Panhandles, low level moisture will be limited (low 40s surface dew points). Instability also doesn`t look great with warm mid level temperatures. However, a small area in the far northwest zones (in close proximity to the shortwave) may see about 500 J/kg MLCAPE develop by late afternoon. The kicker here is that DCAPE will be in excess of 1500 J/kg, with classic inverted-V profiles showing up in the extended RAP and HRRR soundings. Weak flow aloft will keep shear marginal for organized storms (about 20 to 30 knots deep layer bulk shear), but any storms that can push into the northwest zones tomorrow evening could pose a damaging wind risk. A more substantial trough is progged to move down across the northern and central CONUS Sunday into Monday. This will lead to increased northwest flow aloft and also send a cold front into the area late Sunday. The front will lower max temperatures back down around normal for Monday and possibly Tuesday, but until then we will be dealing with high 90s to near 100 degree heat each afternoon through Sunday. Sunday will be the warmest day for most due to slightly better downslope flow in the afternoon and some compressional warming ahead of the front. Palo Duro Canyon may reach or exceed 105 degrees Sunday afternoon. As for storm chances, a lot will hinge on moisture and capping. The NAM soundings indicate increased low level moisture along and behind the front Sunday night into Monday morning, but a strong cap and drier air aloft may keep storms limited in coverage. Models also don`t agree on the thermodynamic profile with varying amounts of CAPE behind the front. For now, utilized a blend of CONS models to keep low end PoPs Sunday night into early Monday morning, as models sometimes under estimate northwest flow patterns. While a severe storm can`t completely be ruled out Sunday night, uncertainly with storm coverage and instability will keep severe mention out. A hail threat could occur if worst case CAPE values were realized behind the front AND storms develop behind the front. High pressure starts building back over the plains towards the middle of next week which should result in a quick warm up back above normal. Storm chances will be limited as we loose the northwest flow for a bit, but some ridge riders or storms forming with convective temperatures being reached can`t be ruled out. Ward && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$
Area Forecast Discussion
National Weather Service Gaylord MI
1134 PM EDT Fri Jun 18 2021 .UPDATE... Issued at 948 PM EDT Fri Jun 18 2021 Quiet out there now. Fire wx parameters got amped up a bit in the late afternoon and early evening, as drier air arrived/mixed down, but RH has risen and winds have decreased with the sun going down. An area of stratocu tried to push into nw Chippewa Co, but is still trying, as it has eroded along the leading edge as it encounters a more well-mixed low-level airmass. Guidance suggests that stratocu could make limited inroads into Chippewa Co, and could reform over far northern Lakes MI/Huron (where mixing was hindered earlier). But widespread clouds are not expected in the north. Bigger concern is with a well-defined shortwave (in wv imagery) progressing across central/northern MN. This wave has helped generate some small bands of surface-based convection. Some of this is expected to survive the transition to nighttime, with at least isolated convection propagating ese-ward across WI during the night. Current activity is a bit further north than earlier progged. Recent RAP runs suggest a shower or two could make a run at Benzie/Gd Trav Cos after 6 am; again, a bit further north than earlier progged. Have extended slight chance pops northward in response (they were already present near MBL and CAD). Min temps will range from the upper 40s in western Chippewa Co, to the upper 50s along our more southerly Lakes MI/Huron beaches. && .NEAR TERM...(Through Tonight) Issued at 353 PM EDT Fri Jun 18 2021 ...Mainly quiet weather tonight... High Impact Weather Potential; None. Pattern Synopsis/Forecast: Parent closed upper level continues to swing through Ontario this afternoon with low amplitude troughing/ height falls sagging into the northern lakes. Secondary well defined short-wave embedded within the larger scale flow is sliding southeastward into northeast North Dakota, along with a smaller area of convection in southern Manitoba. At the surface, surface low pressure is slowly working through eastern Ontario with a diffuse boundary/sharp dewpoint gradient just about through eastern Upper Michigan and beginning to cross through northern Lower Michigan. A strong push of drier air resides behind the boundary with dewpoints dropping from the 60s to the 30s and 40s. Cloud cover has been steadily decreasing across the CWA through the day although we have seen some very isolated showers...most notably near the Soo a bit ago with a nice shower/storm that popped along the boundary. Boundary will continue to cross the region heading into the evening with drier low level air making good inroads. This will continue to thin/clear out the remaining cloud cover as we get into the evening, although another larger area of cloud cover across Ontario will attempt to sneak into the northern parts of the CWA later tonight. Meanwhile, aforementioned secondary short- wave in northeast North Dakota will quickly dive into the western Great Lakes during the overnight hours. Small area of showers/some thunderstorms is expected to develop in the Upper Midwest late this afternoon/early evening and make a run at Lower Michigan early Saturday morning. Right now...that activity is expected to impact mainly central and southern Lower Michigan and just graze our southern counties (along the M-55 corridor) late overnight through Sunday morning. We will see just how much instability remains with this feature to support a low end thunder threat, but no severe weather is anticipated regardless. && .SHORT TERM...(Saturday through Monday) Issued at 353 PM EDT Fri Jun 18 2021 ...Are the Models Right? Possibly a Good Soaker Sun/Mon... High Impact Weather Potential...Thunderstorms possible Sunday afternoon and night. Rain amounts are forecast to be around 1.00" Pattern Synopsis/Forecast and possible impacts...Saturday morning, the models are keying in on a shortwave trough that drops into the Upper Great Lakes. With the NW flow at 500 mb, it will probably miss us, going just south of US-10. The pops will be slight chance to chance along M-55 through the afternoon and then dries out overnight as the system moves out. Sunday, The day itself still looks pretty similar to yesterday`s with the line of showers and thunderstorms moving into the region after 18z/Sun. The main rain from the system looks to be Sunday evening as the sfc low and 500 mb shortwave moves through the region. The GFS is a little faster with the rain moving out just prior to 12z/Mon, and the ECMWF still leaves some showers into the forecast area through Monday morning, but the afternoon and early evening look dry. .LONG TERM...(Monday night through Friday) Issued at 353 PM EDT Fri Jun 18 2021 High Impact Weather Potential...Minimal for now. Extended (Monday night through Friday)...Monday night looks breezy and chilly, to start, but the winds could drop off, and some min temperatures could drop to the mid 30s. Not ready to add frost, but the percentage is non-zero. Tuesday, another 500 mb trough moves through the region. The models have some showers, mainly in the afternoon and evening, going into Wednesday morning now. The GFS makes it look like a MCS. with the new FV3 core for the GFS, we`ll see if this is right. would think that the ECMWF is probably a little better with showers and a few hundredths of an inch. Wednesday may have some showers that linger into the afternoon and clear out in the evening. Temperatures should be a rebound. Thursday the models disagree with the pattern. The ECMWF has more of zonal flow, that doesn`t put any precipitation in the area until Friday. The GFS has the precipitation moving out by Friday morning, and then a second system dropping in Friday night/Saturday morning. While the ECMWF is dry. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1134 PM EDT Fri Jun 18 2021 VFR. Quiet conditions presently, as drier air moves in behind a departing surface trof. An upper level disturbance will pivot into lower MI very late tonight. That could bring showers to the MBL area (and just maybe TVC too) toward and after daybreak. Otherwise quiet VFR conditions continue. Light winds overnight. Nw to n breezes Saturday, a touch on the breezy side (though less so than Friday). && .MARINE... Issued at 353 PM EDT Fri Jun 18 2021 Some gustiness out there today with a few locations occasionally hitting small craft advisory criteria gusts. Winds will be diminishing over the next few hours into tonight, thus not planning any headlines at this point. Some gustiness anticipated on Sunday during the day and a few locations may once again experience small craft advisory criteria at times. But again, not planning on headlines. Stronger gusts anticipated later Sunday night into Monday with headlines likely at that point. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JZ NEAR TERM...BA SHORT TERM...JL LONG TERM...JL AVIATION...JZ MARINE...BA
Area Forecast Discussion
National Weather Service Cheyenne WY
724 PM MDT Fri Jun 18 2021 .UPDATE... Issued at 723 PM MDT Fri Jun 18 2021 Based on the latest hi-res model RH, winds and local fire weather procedures, Red Flag criteria will be met for east-central WY, specifically zones 301 and 302. Therefore, the Fire Weather Watch was upgraded to a Red Flag Warning valid Noon through 8 PM MDT Saturday. Updated the Fire Weather Forecast. && .SHORT TERM...(This evening through Saturday) Issued at 206 PM MDT Fri Jun 18 2021 Stationary frontal boundary that was draped across the region has since pushed further east into Colorado, with high pressure building off the Pacific Northwest. Current radar imagery indicates some isolated convection over Sioux Country, and traveling towards the southeast, with some back-building to the northwest. Should see some more cells develop later this evening across the southern portion of the Wyoming and northward into the Panhandle. Storms will continue to be isolated, with the potential for some severe storms as SBCAPE remain in the 1500 to 2500 J/kg east of the Laramie Range. With these systems, some stronger winds and ping pong size hail are possible. As we transition into the weekend, an additional cold frontal boundary is expected to start digging southward across the CWA before becoming stationary once again across the region. Temperatures will climb to above normal in the mid-80s to mid-90s. On Saturday, strong diurnal heating and decent low-level moisture will yield SBCAPE values greater than 2000 J/kg. Combined with surface to 500mb bulk shear values of 35 to 50 knots, will promote conditions on Saturday to remain susceptible to scattered strong to severe thunderstorms across the southern portion of southeastern Wyoming and the Nebraska Panhandle. Main concern with the current forecast for Saturday exist with the HRRR model solutions with the convection starting a bit too far to the east, and leaving the CWA before any stronger storms develop. After the frontal passage, should start to see conditions calming down with daytime highs on Sunday in the low to mid-70s. There is a chance for continued afternoon thunderstorms on Sunday. However, current model guidance has much of the energy pushing eastward, limiting stronger thunderstorm potentials. .LONG TERM...(Saturday night through Friday) Issued at 206 PM MDT Fri Jun 18 2021 Clipper shortwave moves through the area Monday morning. Looks like a good chance for overnight showers and isolated thunderstorms as GFS...SREF and ECMWF all showing good agreement on timing/location of QPF. Went above guidance on PoPs for Monday morning. Upper ridge builds back into southeast Wyoming Monday night into Tuesday with gusty west winds. GFS 700mb winds 25 to 35kts Tuesday could lead to critical fire weather concerns...especially out across Carbon County. Ridge axis shifts east Wednesday with breezy west winds continuing. Pattern shift towards the end of next week with a slow moving low pressure system over the desert southwest. May see an increase in precipitation as it pulls moisture north out of old Mexico. Right now...mid term guidance still has us dry...but something to watch as this takes place. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 543 PM MDT Fri Jun 18 2021 Latest surface analysis was showing a dry line boundary draped on the foothills of the Laramie Range. This boundary appears to be a trigger for more convection early this evening. A few of these storms may become strong to severe with some potential for left and right movers with the general movement of west to east at around 10kts near KCYS. These storms may tap into some strong shear aloft which may allow them to persist for a couple hours past sunset. Could see some residual fog late tonight in locations that see the storms especially if there is some hail. Otherwise, more scattered convection is possible on Saturday afternoon especially along the I-80 corridor. && .FIRE WEATHER... Issued at 206 PM MDT Fri Jun 18 2021 Near critical fire weather conditions for the Snowy, Sierra Madre, and North Laramie Ranges continues this afternoon with west winds 10 to 15 mph with gusts to 20 mph, humidity 10 to 20 percent, and a Haines Index of 5 to 6. Saturday, following a frontal passage will be winds 15 to 20 mph with gusts to 30 mph and humidity 10 to 15 percent for the North Laramie Range and Converse County, warranting a Fire Weather Watch. The Snowy and Sierra Madre Ranges will be near critical, but the humidity there is expected to be above critical levels due to chances of showers and thunderstorms. A stronger front pushes through southeast Wyoming and western Nebraska Saturday night into Sunday, bringing cooler temperatures, higher humidities, and chances of showers and thunderstorms Sunday and Monday. Tuesday, the above-normal warm and dry pattern returns, allowing the conditions to become near-critical once again for fire weather concerns. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Red Flag Warning from noon to 8 PM MDT Saturday for WYZ301-302. NE...None. && $$ UPDATE...MAJ SHORT TERM...MD LONG TERM...GCC/TJT AVIATION...REC FIRE WEATHER...MD/LK
Area Forecast Discussion
National Weather Service Goodland KS
525 PM MDT Fri Jun 18 2021 .SHORT TERM...(This evening through Saturday night) Issued at 342 PM MDT Fri Jun 18 2021 Overview: The mid-latitude westerlies will shift southward from the Northern Plains (Today) into the Central Plains (Saturday).. as the upper level ridge presently situated over the central/southern Rockies/High Plains weakens and retreats to the Desert Southwest. Through Tonight: Primary forecast concern through tonight revolves around whether or not convection will (1) develop along the CO Front Range/Palmer Divide and (2) progress east toward the CO/KS border. A moderately unstable (1500-2500 J/kg mlcape) albeit relatively cool and capped airmass is in place over the majority of the Tri-State area this afternoon -- on the northern periphery of a thermal/moisture boundary (TMB) extending eastward from Lamar CO to Syracuse KS.. then northeastward from Syracuse to Scott City to Hays. Forcing this aft/eve will be confined to weak/shallow convergence invof the TMB. A considerable north-south moisture gradient exists over the region.. with H85 dewpoints ~15C invof the KS/NE border decreasing to <5C in southwest KS. Thus, while convective inhibition decreases toward the south (invof Syracuse-Scott City where sfc temps are in the low 100s).. so does low-level moisture and instability. At this time.. it appears unlikely that weak low-level convergence will aid in the development of deep convection over southwest KS. Furthermore, persistent cloud cover/showers along the CO Front Range have impeded diurnal heating this afternoon.. decreasing the chance that significant and/or widespread convection will emanate from the mountains/foothills this evening. With this in mind, there is considerable doubt with regard to whether or not convection will materialize to the south (invof the TMB) or to the west (invof the mountains/foothills). With weak flow throughout the column (beneath the ridge aloft).. convection that develops (if any) would likely be disorganized in nature. Simulated reflectivity forecasts via the latest runs of the HRRR and NAM NEST are consistent with the aforementioned reasoning. Sat-Sat night: Expect a greater potential for diurnal convection along the CO Front Range Sat afternoon.. as the ridge aloft retreats toward the Desert Southwest and the mid-latitude westerlies begin strengthening over central portions of the Rockies/High Plains. Simulated reflectivity forecasts via the HRRR and NAM NEST suggest that diurnal convection emanating from the CO Front Range could (perhaps) coalesce and evolve into a linear MCS that progresses eastward into KS during the late afternoon and evening. If that were to occur, significant and/or widespread damaging wind would be possible. However, with the synoptic pattern in a `transition state` and a rather subtle/nuanced SFC-H85 pattern.. there is low confidence with regard to convective evolution and extent/magnitude of severe weather. .LONG TERM...(Sunday through Friday) Issued at 303 PM MDT Fri Jun 18 2021 To start off the extended, high pressure is expected to remain over the Southwest with an upper high over the S California/Baja Peninsula region. An upper level trough will continue southeast across the Central Plains along with a cold front. Timing of the front remains uncertain as the latest guidance pushes it through the Tri-State area by mid-day instead of the evening/overnight hours. Scattered showers and thunderstorms are possible Sunday evening into Monday morning. Temperatures are expected to be a little cooler on Sunday with highs in the mid 80s to mid 90s. Monday, the Tri- State area will be on the bottom edge of the upper level trough moving across the northern CONUS and Canada with northwest upper level flow. Cooler temperatures are expected to move into the area with highs in the upper 60s to upper 70s. Once the showers end during the morning hours, the remainder of the day should be dry as the ridge builds again over the western CONUS. Overnight lows both nights are expected to be in the 50s. Tuesday and Wednesday, the upper level ridge is expected to move east into the Plains. Dry conditions and a warm up are likely. Highs are expected to be in the upper 80s to lower 90s Tuesday and the 90s to near 100 Wednesday afternoon with overnight lows increasing from the upper 50s to the lower 70s by mid-week. As an upper level trough digs south across the Northwest, the ridge will be pushed to the east with westerly/west-southwesterly flow aloft Thursday and Friday. There is a slight chance of thunderstorms Thursday and Friday evenings due to the passage of several shortwave over the area ahead of the upper level trough. Afternoon highs are expected to be in the 90s both days with overnight lows in the upper 50s and 60s. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 525 PM MDT Fri Jun 18 2021 Currently expecting VFR conditions to persist through the forecast period for both terminals(KGLD/KMCK). Winds for KGLD, northeast around 10kts through 11z Saturday, then east 5-10kts. By 15z, southeast around 10-15kts. Winds for KMCK, northeast around 10kts through 08z Saturday, then light/variable. By 14z, east-southeast around 10kts. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...VINCENT LONG TERM...KMK AVIATION...JN
Area Forecast Discussion
National Weather Service Wichita KS
816 PM CDT Fri Jun 18 2021 ...Evening Update... .UPDATE... Issued at 811 PM CDT Fri Jun 18 2021 As of 01z/8pm, a SFC low was located near Hays, with a warm front extending east across northern KS. Meanwhile, a cold front stretched southwest into southeast Colorado. Increasing low-level frontogenesis and convergence within the frontal zone may support a few thunderstorms tonight as far south as I-70. The LLJ may enhance the lift in the vicinity of the frontal zone as well. Recent satellite imagery suggests this increase in lift is already underway in a zone from NW Kansas into south-central Nebraska (evidenced by an increase in mid-level clouds/vertical development over the past couple of hours). Should storms develop as far south as our I-70 counties, they should be elevated/higher-based, possibly only realizing about 250-750 j/kg MUCAPE (based off BUFKIT forecast soundings). This should keep the risk of stronger storms on the low side. Because of the more marginal nature of the moisture, instability, and lift in our area, we`ll continue to hold with a dry forecast through tonight for our I-70 counties, but monitor trends in case an increase in pops is warranted. Martin && .SHORT TERM...(This evening through Sunday night) Issued at 302 PM CDT Fri Jun 18 2021 Bottom Line up Front: Continued hot for most of the area through the weekend, with a cool down expected next week. Storm chances return Sunday evening/night. Another hot afternoon across most of the forecast area as SW downslope flow has led to good mixing and temperatures climbing to near the century mark. A weak frontal boundary has sagged into northern KS, but a fairly stout warm elevated mixed layer (EML) has prevented any showers or storms from developing along it. Convergence along the front isnt very impressive either, so think confidence in anything developing along the front late this afternoon is small. We could see an isolated storm or two develop near the front later this evening, but think the best chance is for areas to the north and northeast of the forecast area. Latest RAP shows low level moisture increasing from the SW this evening and tonight, mainly into NE KS. Lots of warm air aloft across central and south central KS with 700h temps around 14-15 degrees C., which will effectively cap off any kind of shower/storm from developing in the forecast area late tonight. The best chance for anything to develop overnight will be well to the NE of the forecast area, but think these chances are small as well. A rather tricky temperature day on Sat across central KS, as the frontal boundary remains stationary or possibly wobbles a little further south into central KS for Sat afternoon. Increased cloud cover and a wind shift to the east, may lead to max temps almost 5- 10 degrees cooler in central KS, depending on the frontal position. Think most locations south of the front will once again flirt with the century mark for max temps, similar to today`s high temps. But a little concerned max temps may be a few degrees warmer than today, with model certainty, 75th percentile, showing this slight uptick in max temps. For now will go with persistence for temps. For Sat night, upslope flow just to the north of the boundary, suggests that areas in NW KS could see thunderstorm development for Sat evening/night, with convection developing into some sort of forward propagating complex of storms late Sat night. Propagation vectors suggest most of this complex will stay well to the north or NW of the area (across northern KS/southern Neb), with little movement to the SE. Could see the southern edge of this complex clip portions of central KS, for areas north of I-70, so will keep a small pop in for this chance. The rest of the forecast area will dry and warm conditions continue into Sunday. For Sunday, another hot day is expected ahead of a southwestward moving frontal boundary for Sunday afternoon. Compressional heating just ahead of the front will probably lead to max temps climbing a few degrees warmer, with areas along and west of I-135 seeing max temps of 100-103. As the front pushes south, a warm elevated mixed layer will probably keep convection from developing along the front for most of the daytime hours. But as the front drops into southern KS for the evening hours, the low level jet increases over the top of the boundary for a chance of post frontal elevated showers/thunderstorms for Sunday evening and Sunday night. Ketcham .LONG TERM...(Monday through Friday) Issued at 302 PM CDT Fri Jun 18 2021 Models are in similar agreement showing the upper ridge amplifying over western Canada with downstream upper trough digging further south over for the central plains early next week. This will cause a cooler airmass to push southward across the region with below normal temperatures providing some relief from the heat for Monday into Tuesday. Thunderstorm chances look more favorable along the front for Monday afternoon/evening. A few strong/severe storms will be possible with increasing wind shear aloft. Meanwhile, temperatures will begin to warm again for Wednesday and Thursday. In addition, long range models show a decent signal for elevated convection potentially affecting the region early Wednesday/Thursday mornings as deeper moisture streams back northward into a mid-level baroclinic zone. Ketcham && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 642 PM CDT Fri Jun 18 2021 * LLWS possible tonight * Conditional TSRA risk tonight (north-central KS) As of 23z/6pm, a surface low was centered near KHYS, with a cold front running southwest into southeast Colorado. East of the low, a warm front stretched east across northern Kansas. SHRA and TSRA have been ongoing north of the warm front for the past several hours across southern Nebraska, and it appears that this is where the greatest risk will remain through tonight. However, there is a low chance of a few SHRA or TSRA developing closer to the surface low (ie. near/north of I-70) as the low-level jet develops this evening. Because of the low risk, I`ll continue to keep TSRA out of the TAFs in that area for now, but monitor for possible amendments later. Otherwise, the main issue tonight will be LLWS as the low-level jet develops. By Saturday morning, the low- level jet will begin to weaken, but there will probably be another overlap of mixing and modest winds aloft, allowing gusty surface winds to develop by mid-morning (similar to what occurred this morning). Of note, though, as the frontal boundary sags south through tomorrow, wind speeds and direction become less certain. For KRSL/KSLN/KGBD, this may mean a period of lighter, less gusty, winds. EXTENDED PLANNING OUTLOOK: We continue to expect at least a modest risk of TSRA through the weekend across parts of the area. Initially, it appears the greatest risk will be across central Kansas Saturday evening/night, followed by an expanding risk on Sunday. Martin && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 74 99 74 102 / 0 0 10 10 Hutchinson 74 100 75 102 / 0 0 10 10 Newton 74 98 74 101 / 0 10 10 10 ElDorado 73 94 73 98 / 0 10 10 10 Winfield-KWLD 72 96 72 99 / 0 0 0 0 Russell 72 97 74 99 / 10 0 20 10 Great Bend 72 98 74 100 / 10 0 20 10 Salina 75 100 75 102 / 10 10 20 10 McPherson 74 99 74 102 / 0 10 10 10 Coffeyville 71 93 70 96 / 0 0 0 0 Chanute 73 94 72 95 / 0 0 0 10 Iola 73 94 72 95 / 0 10 10 10 Parsons-KPPF 71 93 71 95 / 0 0 0 0 && .ICT WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...RM SHORT TERM...Ketcham LONG TERM...Ketcham AVIATION...RM
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
551 PM CDT Fri Jun 18 2021 .SHORT TERM... (Through Late Saturday Night) Issued at 247 PM CDT Fri Jun 18 2021 So far near record temperatures this afternoon with heat index values topping out above 105 at a number of locations. Otherwise, storms chances remain conditional through the evening hours, mainly over portions of northeast Missouri and west central Illinois. Latest operational EMC RAP indicating mid level lapse rates near 8 with MU CAPES 2500+ J/kg and 0 to 3km shear 25 to 30kts across far northern portions of the forecast area. So if CAP can weaken enough and low level jet ramps up to allow convection to initiate, could see isolated/scattered strong to severe storms tonight for portions of northeast Missouri and west central Illinois. The main threats would be damaging winds and large hail. Storm chances will lessen by Saturday morning, then ramp back up during the afternoon hours. The location of development Saturday afternoon will depend on where any possible remnant boundaries are located, as the main cold front will stay north of the forecast area. Otherwise, heat and humidity will affect the forecast area once again with highs in the 90s. A bit more mixing of the atmosphere tomorrow, so heat index values will top out between 95 and 100 most locations, though St. Louis metro area will be over 100 once again. As for heat headlines, will extend the heat advisory for the St. Louis metro area through Sunday due the longevity of 100+ heat index values through this period. Byrd .LONG TERM... (Sunday through Next Friday) Issued at 247 PM CDT Fri Jun 18 2021 Latest deterministic and ensembles still have differences in timing, strength and placement with the front through Monday. GFS is remains the strongest and fastest with the front exiting the forecast area by midday Monday, while the ECMWF is slower. However, the latest run of the ECMWF is a tad faster than previous runs. Will stick with the NBM solution, which is a decent blend of the models. With the front north of the forecast area on Sunday, it will be another very hot day with highs in the 90s. Decent mixing, so dewpoints will lower through the day with heat index values between 95 and 100 most locations, though could see above 100 in the immediate St. Louis metropolitan area once again. As for chances of showers and storms, the best chances remain in our far northern counties closer to the frontal boundary earlier in the day. Will see increasing instability through the afternoon and evening hours, mainly along and just ahead of the front. MU CAPES of 2500+ J/kg combined with favorable mid level lapse rates and deep-layer shear (30 to at least 40 kts) will generate some strong to severe storms. By Sunday night the front will continue to slide south through the area eventually exiting by midday Monday. So showers and storms will taper off Monday evening. Highs on Monday will range from the low 70s to the low 80s. Otherwise, cooler and drier weather through midweek before next system approaches the region next Thursday and temperatures begin to warm back up. Byrd && .AVIATION... (For the 00z TAFs through 00z Saturday Evening) Issued at 518 PM CDT Fri Jun 18 2021 A cold front extends from MI southwest through northern MO. Showers and storms can be expected along this front tonight which may impact UIN by late tonight. Most of the convection should remain north-northeast of the rest of the taf sites, although showers/storms may get close to the St Louis metro area Saturday afternoon. Outside of the showers/storms VFR conditions will continue with mainly high level cloudiness. The surface wind will be variable at UIN close to the front and any outflow boundaries from convection. Further south the wind will be mainly south- southwesterly through the period. SPECIFICS FOR KSTL: A cold front extends from MI southwest through northern MO. Showers and storms can be expected along this front tonight. Most of the convection should remain north-northeast of STL, although showers/storms may get close to STL Saturday afternoon. Outside of the showers/storms VFR conditions will continue with mainly high level cloudiness. The surface wind will be mainly south-southwesterly through the period. GKS && .CLIMATE... Issued at 258 PM CDT Wed Jun 16 2021 Record Highs: Fri 6/18 STL 100(1953) COU 100(1953) UIN 99(1913) && .PRELIMINARY POINT TEMPS/POPS... Saint Louis 80 98 76 98 / 20 40 30 10 Quincy 73 92 71 93 / 60 30 20 20 Columbia 75 94 71 95 / 10 20 5 10 Jefferson City 75 97 72 96 / 5 10 5 5 Salem 75 94 72 94 / 30 40 30 10 Farmington 72 94 70 94 / 20 10 5 5 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...Heat Advisory until 7 PM CDT this evening for Audrain MO-Boone MO-Callaway MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO- Lincoln MO-Marion MO-Moniteau MO-Monroe MO-Montgomery MO- Osage MO-Pike MO-Ralls MO-Saint Francois MO-Sainte Genevieve MO-Shelby MO-Warren MO-Washington MO. Heat Advisory until 7 PM CDT Sunday for Jefferson MO-Saint Charles MO-Saint Louis City MO-Saint Louis MO. IL...Heat Advisory until 7 PM CDT this evening for Bond IL-Calhoun IL- Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL- Marion IL-Montgomery IL-Pike IL-Randolph IL-Washington IL. Heat Advisory until 7 PM CDT Sunday for Madison IL-Monroe IL- Saint Clair. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
913 PM EDT Fri Jun 18 2021 .SYNOPSIS... A Mesoscale Convective System may impact parts of our region through early Saturday morning. Multiple fronts will impact our region through Tuesday. High pressure returns during the middle to later parts of next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 9:15 PM UPDATE: Currently across our region, only seeing some mid-upper level clouds. More menacing are the two areas of developing convection nearby. The first, closest to home, is some weaker storms to our north over east-central PA, moving due east. Some cells are starting to build further and further south in this line, and could impact western portion of our forecast in the next couple of hours. The most pressing concern is the developing MCS over the Ohio Valley. Several severe thunderstorms are present within this line. We will be watching both of these areas carefully over the coming hours. The recent 00z run of the HRRR has started to get a better handle on the current state of convection across the Ohio Valley. With the MCS moving into a much less favorable environment, tend to believe it fizzles out as it moves out of Ohio into KY/WV. All in all though, this activity should all stay well to our west. The only thing that could happen to impact our area is that the outflow from this MCS could set off another area of convection over eastern OH (as depicted in the 21z RAP). That could then make a run at our region late overnight tonight between midnight and 4 AM or so. So, have adjusted POPs/Wx forecasts to account for current observations and to account for the most accurate guidance at the moment. All being said though, the thought is maintained that a deep layer of westerly winds will likely limit the threat for showers and thunderstorm further east of the Allegheny front. If there is any threat for severe storms, and I think that is low at this point, it should end at the Allegheny Front. This thought is still maintained in the most recent SPC severe outlook as well, keeping that area in the marginal risk category, with damaging winds the primary threat. Notably though, overnight lows will be very mild in the mid to upper 60s to lower 70s across the region, which is about 10 degrees above normal. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... PREVIOUS DISCUSSION: An upper level trough will drop down into the northeast US on Saturday. A surface low associated with the upper trough will pass through the upper parts of the NE US with its corresponding front dropping into parts of NY. Our region will remain on the warm side of the front which will allow for temperatures to trend up into the mid to upper 90s on Saturday. The threat for thunderstorms on Saturday have decreased over the past few days. The upper trough has trended further northward while an upper jet moving through PA remains disconnected from a secondary shortwave dropping into our region Saturday afternoon. The combination of CAPE values hovering around 2000-3000 across the MD/PA border along with modest shear and a shortwave moving through Sat afternoon may lead to areas of strong thunderstorms or a localized convective line. CAMS overall have trended downward with the thunderstorm coverage and I believe the main threat area will be focused along the MD/PA border which will be near the best shear. The threat for showers and thunderstorms should start to taper off after sundown with only isolated showers or storms possible into Sunday morning. Overnight lows will be mild once again in the mid to upper 60s to lower 70s. Sunday will likely start off dry but as diurnal heating begins, temperatures will rise up into upper 90s. CAPE values will likely rise above 2000 once again, but the upper jet is expected to weakened leading to much lower shear values throughout the layer. The lack of good forcing and shear will limit the widespread thunderstorm threat but the combination of hot and humid conditions along with decent lapse rates will allow for pop up showers and thunderstorms. As CAPE values will be close to 3000 on Sunday, I can`t rule out a localized strong thunderstorm threat due to pulse storms. The threat for thunderstorms should taper off after diurnal heating shuts off with only a small chance for storms Sunday evening mainly in the southern parts of our region due to an approaching low. && .LONG TERM /MONDAY THROUGH FRIDAY/... Generally good agreement amongst the latest guidance suite in regards to the long term period. Confidence is increasing for the remnants of a tropical system originating in the Gulf of Mexico to track just to our south and east, away from the CWA on Monday. If this trend remains the same over the next few model run cycles, then don`t foresee any hazardous impacts to the region. If the track shifts slightly more north and west, then the potential for heavy rainfall across the region would be the main hazard. However, the first scenario seems more likely at this point in time, given the advancement of a cold front which is slated to cross the region late Tuesday into Wednesday. Hot and humid conditions continue on Monday and Tuesday with temps in the low to mid 90s for most and dewpoints in the upper 60s to low 70s. Even if the remnant low passes offshore, the unstable airmass would still poise the chance for scattered afternoon showers and thunderstorms Monday. However, the bigger threat is Tuesday afternoon and evening as the front advances further south. A much cooler and drier airmass is present on the backside of the boundary. If the timing of the front remains the same, given the drastic differences in air masses, ample moisture, instability, 0-6km shear, and lift, would signal a potential severe weather event across the region. Flooding or flash flooding could also become an issue given high PWs. Cooler and drier conditions are expected for the middle and later portions of next week as high pressure regains control of the region. However, heat and humidity may begin to build back into the region once again towards next weekend. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Mid to high level clouds will continue to build over all terminals through the evening as an MCS over the Ohio Valley slowly approaches. The overall thunderstorm threat from this system for our terminals remains low but MRB has the best chance during the 4Z to 8Z period. Winds will remain out of the south with VFR conditions expected. Showers and thunderstorms will be possible for terminals mainly north of the DC metro during Saturday afternoon. Pop showers and thunderstorms will be possible at terminals on Sunday but VFR conditions along with winds out of the south are expected this weekend. Mainly VFR conditions are expected on Monday and Tuesday under a southerly flow. However the chance for afternoon showers and thunderstorms will remain elevated given the unstable air mass in place. Therefore, periods of sub-VFR CIGs/VSBYs are possible both days. However, there is a higher chance for more widespread severe weather on Tuesday as a cold front approaches the region. IAD, BWI, MTN, and DCA have the best potential at this time to see any of said severe weather Tuesday. && .MARINE... Small Craft Advisories will remain in effect for portions of the waters through late Saturday morning, owing to gusty south to southwesterly flow. Should see a lull during the afternoon on Saturday, but can`t rule out some gusts near SCA criteria with a pretty well-mixed boundary layer. This will likely be the case again on Sunday as well, with the biggest potential on both days being across the lower Bay zones. Low pressure likely stays just southeast of the area Monday. SCA conditions are likely ahead of a strong cold front late Monday into Tuesday. This front may also spawn strong thunderstorms, especially late on Tuesday. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 6 AM EDT Saturday for ANZ530>533- 538>542. Small Craft Advisory until 11 AM EDT Saturday for ANZ534-537- 543. Small Craft Advisory until 6 AM EDT Saturday for ANZ536. && $$ SYNOPSIS...JMG NEAR TERM...CJL SHORT TERM...JMG LONG TERM...MSS AVIATION...MSS/CJL/JMG MARINE...MSS/CJL
Area Forecast Discussion
National Weather Service Marquette MI
724 PM EDT Fri Jun 18 2021 .SHORT TERM...(This evening through Saturday) Issued at 359 PM EDT FRI JUN 18 2021 ...Very gusty winds and critical fire weather conditions will continue into early evening... WV imagery and RAP analysis indicated a mid/upper level trough through northwest Ontario in a nearly zonal flow through the northern CONUS. Another upstream shortwave over the Dakotas will dive se across the Upper Midwest and bring a cold front across the region tonight. The main story today has been the strong and gusty west-northwest winds across the area ahead of the approaching frontal system which in combination with the deep mixing through a warm and very dry airmass is creating critical fire weather conditions across the U.P today. Houghton County Airport has gusted near 60 mph this afternoon while many other locations have gusted between 35 and 45 mph, especially west half. Meanwhile RHs have ranged from the teens to mid 20 percent range across much of the fcst area. U.P. residents are reminded to avoid outdoor burning or any outdoor activities which could cause sparks today. Tonight, Models indicate another shortwave over the Dakotas will track just west of the U.P. late tonight into Sat morning and bring a cold front through the region late tonight and Sat morning. Gusty west winds will diminish this evening with the loss of diurnal mixing and then shift northerly behind the cold front tonight. Min temps will generally drop into the mid 40s to lower 50s across the cwa under clear to partly cloudy skies. Cold advection behind the front and northerly winds off Lake Superior on Saturday will result in a cooler than normal day across the area. There could be some residual stratcu cloud cover with some steeper low-level lapse rates due to the colder airmass advecting across the area, although otherwise expect partly cloudy skies. Max temps will range from the 60s near Lake Superior to the lower 70s farther inland and along the WI stateline. .LONG TERM...(Saturday night through Friday) Issued at 359 PM EDT FRI JUN 18 2021 Saturday night, westerly flow aloft and dry mid levels will lead to mostly clear skies (after diurnal cumulus over the interior diminishes) and light to near calm winds. On Sunday, a short wave rounding the base of the long wave trough centered over Hudson Bay will trigger cyclogensis along an associated strong cold front that will be surging southeastward through the Northern Plains and Upper Midwest. The first wave of mid- level isentropic lift/theta-e advection looks to overspread the U.P. Sunday afternoon with widespread showers. This will be followed by additional waves of isentropic lift and low-level moisture convergence Sunday evening. PWATs ahead of the front are modeled to rise to around 1.50" over parts of the area, but with the cyclone tracking more or less overhead, all of the instability will remain well to the south. Thus, despite this higher moisture content, neither thunderstorms nor flooding rains are anticipated. Most of the rain should move out of the area after midnight Sunday night, although it looks like a few wrap-around/upslope showers enhanced by marginal lake-based instability will linger into Monday morning across the west half. The main story of the long-term period still looks to be the unseasonable chill Monday and Tuesday. GEFS and EPS mean 850 mb temps continue to be around +1 to +2 C Monday morning through Tuesday afternoon which is in the 1st to 5ht percentile of climatology for this time of year (or even lower looking at just EPS by itself). It certainly won`t feel like the first full day of astronomical summer on Monday! The only redeeming factor will be the clearing skies as the day goes on Monday, but that will only help temps get into the mid 50s to mid 60s for highs. On Tuesday, increased cloud cover will mostly counteract slight warming aloft, although highs will nudge slightly warmer into the mid 60s. Monday will also be on the breezy side with the cold air aloft leading to deep mixing. Then a warming trend begins again for the middle of next week. By Thursday, GEFS and EPS mean 850 mb temps climb back to around 13-15 C which should translate into highs in the upper 70s and low 80s. A cold front may then approach the area late Thursday or Friday and bring with it the next chance for showers and possibly a thunderstorm. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 723 PM EDT FRI JUN 18 2021 VFR conditions are expected through the TAF period. Gusty winds will decrease this evening and shift north, remaining light through Saturday. A lower cloud deck could develop Saturday morning at KSAW and KIWD but it is expected to remain just above MVFR CIG thresholds. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 359 PM EDT FRI JUN 18 2021 Southwest to west winds in the 15 to 25 knot range will veer northwest to north 10 to 20 knots tonight into Saturday. With continued strong stability, higher platforms will see the higher wind values into this evening. Winds less than 20 kts are expected Saturday night into Sunday, but another low pressure system may increase northwest winds up to 30 knots late Sunday night through Monday with a few gale gusts to 35 knots possible over the east half. Winds should then die down below 20 knots Monday night and then stay that way into midweek. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Red Flag Warning until 9 PM EDT /8 PM CDT/ this evening for MIZ001>007-009>014-084>088-095>097. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Voss LONG TERM...RJC AVIATION...NL MARINE...Voss
Area Forecast Discussion
National Weather Service Paducah KY
655 PM CDT Fri Jun 18 2021 .UPDATE... Issued at 655 PM CDT Fri Jun 18 2021 Updated aviation discussion. && .SHORT TERM...(Tonight through Sunday night) Issued at 309 PM CDT Fri Jun 18 2021 Temperatures have struggled to reach the middle 90s in most places today, but dewpoints have over-performed enough in a narrow zone to verify the Heat Advisory from Perryville through Mt Vernon. Will let it continue until its expiration at 7 PM. A modest cu field has developed in that zone of greatest moisture mostly over the hills in southeast Missouri. Not much evidence in guidance for any convection to develop, but with greater moisture than expected an isolated storm or two cannot be completely ruled out. We will need to keep an eye on that area. As for tonight, the HRRR has been steadfast in keeping convection well north of our region through the night, but a few other members of the 12Z HREF are trying to push convection southeast through the I-64 corridor overnight into Saturday morning. However, the HREF probability of winds even to 30 mph are quite low, so we are not overly concerned with the severe potential. It looks like Saturday could be dry after any morning convection clears to the east of the area, but there will be a concern for more scattered convection to develop northwest of the area and possibly slide along the I-64 corridor again in the afternoon and evening. Confidence on Saturday is quite low, but we have limited slight chance PoPs to I-64, keeping the rest of the region dry. Sunday, we should be safely located between a southeastward moving cold front and a northeast moving tropical system. Cannot rule out a stray shower or storm reaching the Ft Campbell and Todd county areas of west Kentucky, but would expect the entire area to stay dry. We will have slight chance PoPs over most of the region overnight Sunday night, ahead of the aforementioned cold front. As for temperatures, the consensus of guidance is for high temperatures to hold in the lower to mid 90s for highs over the weekend, but dewpoints will stay more in the upper 60s to lower 70s, so although it will be hot, heat indices are not expected to reach above 100 for any significant period of time. If convection does make it farther into the area Saturday, that could hold temperatures down to some extent, but right now we do not expect that to happen. Low temperatures may not drop much below 80 across the north tonight if we can avoid any convection or outflow, but will stick with lower 70s throughout the area for now. It will be a bit less mild Saturday night, but with winds increasing ahead of the front, Sunday night could be quite mild with mid to upper 70s expected. .LONG TERM...(Monday through Friday) Issued at 309 PM CDT Fri Jun 18 2021 The big story in the extended remains rain chances Monday/Monday night followed by much cooler and less humid conditions for a couple of days thereafter. Monday still appears to bring the best overall chance of showers /thunderstorms as 500mb heights fall in response to an upper level trough moving across the FA. At the surface, a cold front will sweep SE across the FA Monday and Monday night. These features combined with ample low level moisture and heating continue to point to likely POPs for the PM hours Monday. The GFS seems to underplay QPF, whereas the other deterministic solutions and NBM are a bit more robust which seems reasonable given the transitional dynamics. Believe a few strong to severe storms remain possible with/before FROPA Monday afternoon and evening - along with the usual possibility of localized flooding. Have max temps currently progged for the mid to upper 80s Monday but slower FROPA/fewer clouds could boost temps a bit more. Surface dewpoints Monday will not be overly high for this time of year with upper 60s the current thinking. Timing wise for the end of the rain chances, the GFS clears things out pretty quick after 06z Monday night, whereas the EMCWF and other solutions are not so quick. Bottom line, is will continue rain chance after midnight Monday night mainly across W KY and SW IN. Tuesday and Wednesday will offer another refreshingly cool and less humid air mass as surface high pressure is entrenched across the area in a northwesterly upper level flow with surface dewpoints as low as the upper 40s by Tuesday afternoon. The result will be low temps mostly in the 50s by Tuesday morning and even a couple of degrees lower (mid 50s on average) Wednesday morning. High Temps Tuesday will only make it to the mid and upper 70s...and into the lower 80s Wednesday. Thereafter, upper level ridging persists over the south central U.S. and the NW flow aloft relaxes with overall model solutions bringing one or more 500mb short waves SE across the FA. Given the considerable variations in solutions in these last 2 days of the extended, will simply keep chance POPs in for that period for now. What is more clear is that both temps and low level moisture will be on the increase next Thursday and Friday. && .AVIATION... Issued at 655 PM CDT Fri Jun 18 2021 VFR conditions are expected across the region in general. However, early Sat, there is a limited possibility of showers or tstms developing along the I-64 corridor and possibly into extreme northern counties of the Pennyrile region. The probabilities are low enough to forgo a mention of this activity in the TAFs at this time, but this may change. Meanwhile, a persistent southwesterly wind sustained at 12 knots or less will prevail. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ SHORT TERM...DRS LONG TERM...RS AVIATION...DB
Area Forecast Discussion
National Weather Service Mount Holly NJ
950 PM EDT Fri Jun 18 2021 .SYNOPSIS... A warm front is forecast to move across the region tonight into Saturday, before a surface trough develops across the east coast, followed by an approaching cold front Saturday. This front will likely stall near the area Saturday night into Sunday, then lift back northward Sunday night into Monday. A stronger cold front is forecast to move across the east coast around Tuesday. High pressure returns to the east coast Wednesday, then shifts offshore Thursday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 930 pm update: Confidence is pretty low on what will transpire overnight. The convection-allowing models are all over the place, with the 18z NAM Nest suggesting a pretty loud night in our northwest CWA, with the HRRR noticeably quieter (though still peppered with scattered showers/isolated storms). Upstream data suggest the NAM Nest is way overdone, with an evolution similar to the HRRR much more reasonable. Think there is increased signal for some precipitation overnight in general, but the antecedent environment and upstream data prompt keeping the forecast close to what was inherited for now. Confidence for Sunday is similarly low, with the HRRR on the rambunctious side for afternoon convection, the NAM Nest on the quiet side, and the FV3/ARW(s) siding on the slower side. Results will be tied strongly to the evolution of convection upstream overnight, resultant effects on upscale energy transfer, and the development of diurnal instability during the day. My feeling is that vigorous convection is likely somewhere near/in the CWA, but fine-tuning the area/timing is a dubious task at this juncture. What is clear is that the ambient environment is favorable for severe weather on Saturday afternoon/evening, but the threat is conditional. Previous discussion follows... As the surface high and mid level ridge shift further east this evening, an area of low pressure will traverse Ontario into Quebec. An associated trough axis with this low is expected to progress east and stall over our region late tonight. While widespread precipitation is not expected tonight, some lingering convection from convective complexes further upstream may nudge into the region after midnight. It is questionable if the showers will even make it this far east as by that time we should have a robust nocturnal inversion, and relatively stable boundary layer. Southwesterly return flow continues through the day tomorrow. Consequently, expect warmer conditions tomorrow (as compared to today) despite mostly cloudy conditions. As far as storm potential Saturday and Saturday night, most 12Z guidance was notably slower (compared to previous runs) with the cold front and the mid level short wave trough. If this trend holds, the best lift associated with both of these features won`t be over our region until after 00Z (late Saturday evening). While it still appears there is a threat for strong, even severe winds (given effective shear values of 30 to 35kt and a dry layer in the mid levels increasing the risk for dry air entrainment/downbursts), the threat is more limited than if these features would be faster. If the timing speeds up at all, then there is a more widespread threat since the best lift, highest shear values would be coincident with the maximum instability. As it is now, CAPE values, even MU CAPE values should be limited by the time we see much of the showers and storms. One caveat to what is mentioned above, a few models depict convective initiation on the remnant trough axis (that stalls over our region tonight) by mid day tomorrow. With limited lift, coverage should be limited, but if any storms develop Saturday afternoon, there is an threat for severe storms. The surface front is expected to stall over or near our region late Saturday night. Coverage of showers and storms should diminish though as the mid level short wave trough sides east of the region after midnight. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... The front remains stalled near the Mid Atlantic region Sunday, before it begins to lift back northward Sunday night into Monday. Nearly zonal flow will be in place across the area Sunday into Sunday night, with a couple of weak short wave/vorticity impulses moving across the area. Mostly dry weather is expected Sunday into Sunday night, with a few isolated showers or thunderstorms with the weak short wave activity. && .LONG TERM /MONDAY THROUGH FRIDAY/... A warm and unsettled start to the the long term period is expected, followed by cooler and quieter for the latter half of the long term period is expected toward the end of the week. By Monday, the frontal boundary will have lifted back northward and be well to our north during the day and Monday night. Several short wave/vorticity impulses are forecast to move across the area Monday and Monday night. The flow aloft shifts to the southwest, allowing for added moisture to the region, and any short wave/vorticity impulses could lead to a chance of showers and thunderstorms Monday afternoon and Monday night. We are still watching the low pressure/possible tropical remnants moving out of the Gulf of Mexico. The GFS and NAM flatten the system into more of a embedded surface trough as it moves offshore to our south, while the ECMWF and Canadian and other guidance maintain an actual low as it moves offshore. The overall consensus is to keep the system south and east of the area as it moves offshore and out to sea Monday night. On Tuesday, a cold front a forecast to move across the area, although there are differences between the guidance. The GFS is the fastest and pushed the front offshore during the morning Tuesday, while the ECMWF, Canadian, and other guidance are slower with the frontal passage, pushing it offshore during the afternoon. If the front delays long enough, there could be some instability that develops across the area, leading to a chance of thunderstorms.. However, if the front moves into the region earlier, then the instability would be cut off enough to limit any severe activity. Regardless of the strength of the instability, long term guidance does indicate a good possibility of a period of enhanced rainfall, the timing is about 6-12 hours different. As we move toward the end of the long term, Wednesday through Friday, high pressure shifts into the Mid Atlantic and northeast, which will provide a cooler and drier end to the long term and end of the week. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...Mostly VFR expected. However, there is a chance of showers and maybe a thunderstorm, generally northwest of the Philly terminals (highest probabilities at RDG/ABE). Brief restrictions may occur in their vicinity. Additionally, CIGs may lower to MVFR during and for a time after any showers occur. Again, best chances of this are at RDG/ABE. Winds generally south to southwest up to 10 kt. Some southwest LLWS is expected overnight, generally near/east of the Philly terminals. Moderate confidence. Saturday...Any early morning MVFR CIGs becoming VFR by 14z-15z. Predominant VFR expected thereafter. There is a chance of storms during the afternoon, but models are wildly different in timing/coverage. Confidence is too low for inclusion in the TAFs at this time. Winds generally west to southwest around 10 kt with occasional gusts to 20 kt. Moderate confidence in the morning; very low confidence in the afternoon. Outlook... Saturday night...Prevailing VFR, though showers and storms especially between 00 and 09Z could briefly lower conditions to MVFR or even IFR. Winds gradually shifting from southwesterly to westerly and even northwesterly 5 to 10 kt. Moderate confidence overall, but low confidence on the details of convection. Sunday-Sunday night...Generally VFR conditions expected. West winds 5-10 knots with gusts 15-20 knots. Moderate confidence. Monday-Tuesday night...Generally VFR conditions expected. However, showers and thunderstorms may occasionally lead to lower conditions, especially later Tuesday. South to southwest winds 5-10 knots with gusts 15-20 knots. Low confidence. Wednesday...VFR conditions expected. West to northwest winds 5- 10 knots. Moderate confidence. && .MARINE... 930 pm update: Evening observations indicate advisory conditions have commenced on the Atlantic waters, with no changes needed for the advisory at this time. Atlantic coastal waters: Southerly winds and seas will continue to build through late this evening resulting in Small craft advisory conditions on the coastal waters. The prime period for SCA conditions will be this evening through dawn overnight. By early Saturday morning winds and seas should start to diminish. Once seas subside below 5 ft, winds and seas should stay below SCA criteria through Saturday night. However, locally higher seas and winds are possible in the vicinity of any thunderstorms Saturday night. Delaware Bay: Winds and waves should stay below SCA criteria through Saturday night. However, locally higher winds are possible with any thunderstorms Saturday afternoon and night. OUTLOOK... Sunday-Sunday night...Conditions mostly remain below advisory levels, but winds will gust around 20 knots at times. Monday-Tuesday night...Winds are forecast to remain below advisory levels, however seas are forecast to increase to 5+ feet Monday-Tuesday night. Depending on the track and intensity of the remnants of a low/potential tropical system moving out of the Gulf this weekend, winds and waves could build even higher. A chance of showers and thunderstorms which could create locally higher winds and waves Wednesday...Conditions will lower back below advisory levels. RIP CURRENTS... Overnight, a moderate risk of rip currents is possible, as southerly winds briefly increase. This will be especially the case on the more favorably oriented coast of central/southern New Jersey. However, conditions should improve during the day Saturday, with a low risk of rip currents expected through Sunday. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory until 10 AM EDT Saturday for ANZ450>455. && $$ Synopsis...Robertson Near Term...CMS/Johnson Short Term...Robertson Long Term...Robertson/Staarmann Aviation...CMS/Johnson/Robertson Marine...CMS/Johnson/Robertson
National Weather Service Charleston WV
845 PM EDT Fri Jun 18 2021 .SYNOPSIS... A cold front approaches tonight but stalls, lifting back to the north Saturday. Cold front Monday. High pressure middle of next week. && .NEAR TERM /THROUGH SATURDAY/... As of 840 PM Friday... Area of showers and strong/severe storms to our northwest continues to move southeast towards our area. There is not much consensus between the models dealing with this convection. The HRRR appears to have the best handle on it at this time. If you believe the HRRR, this convection should weaken and dissipate as it moves into our southeast Ohio and northeast KY counties. Feel that some of these storms should make it our counties before midnight. After that time, have decided to just make some tweaks to the earlier POPs as there is little agreement with what is going to happen. As of 105 PM Friday... Models show that a line of convection moving toward the area in Ohio and north central Kentucky should weaken considerably or dissipate. Additional convection is expected to form upstream this afternoon, providing the main focus for the weather tonight. With a decent low level jet and helicity values of 200-300 across Ohio and northern West Virginia, there is some concern that storms could produce damaging winds or possibly a tornado, regardless that they will generally be occurring after sunset. Models continue to struggle with the location and timing of these storms however. Models are also showing bullseyes of heavy rainfall across northern portions of the region. Again, models struggle with the exact location. Have added Greenup county in Kentucky and Lawrence county in Ohio to the Flash Flood Watch. Will continue to monitor the situation to see if any future adjustments need to be made based on where the convection forms. Models continue to struggle on Saturday, as the location of tonight`s weather will greatly affect Saturday`s weather. Regardless, there should be an area of showers and thunderstorms moving across the area, with the best chances over Ohio and northern West Virginia closer to the frontal boundary. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... As of 215 PM Friday... The front is expected to continue to be stalled out to the north- northwest of the area as an upper level shortwave moves through, allowing for showers and thunderstorms to remain possible. Showers and storms will likely persist through Saturday night with the heaviest chances along the northern portion of the area. However, there is still quite a bit of uncertainty with how widespread and with the exact timing of these storms. Additional flooding issues will be possible Saturday night, particularly in any areas that already received heavy rainfall Friday night and Saturday. For Sunday there is a marginal risk for severe weather clipping part of the southeast OH counties, but overall expecting storms to be relatively isolated and non-severe. However, with the rain received earlier in the weekend, could have potential flooding issues if any thunderstorms move over an area that was already hit previously this weekend, but not expecting widespread water issues at this time. Temperatures on Sunday are expected to be in the mid to upper 80s for the lowlands and 70s to mid 80s along the higher elevations, which will provide daytime heating to assist with shower/storm development on Sunday. As this front finally lifts away from the area, there may be a drier period possible Sunday night into Monday ahead of the next system. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 220 PM Friday... Monday may start off mostly dry with a few scattered showers and storms possible as the upper shortwave moves away from the area and the next system begins to move in. A cold front approaches sometime Monday afternoon/evening bringing another chance for showers and thunderstorms ahead of the front. At the upper levels, a trough will move in from the west over the area through Tuesday providing additional forcing for showers and storms to occur. Some stronger storms may be possible with this system with models indicating some instability present this far out. The GFS is slightly quicker to bring this front into the area Monday afternoon while the ECMWF and Canadian show a similar timing with bringing it in slightly later Monday evening. This front will gradually move through on Tuesday, exiting by sometime Tuesday night. Models are keeping the potential tropical system further to the southeast and then off the east coast, so currently not expecting this system to affect the area. Following the cold front, upper ridging attempts to build in and surface high pressure is expected to settle into the area giving way to a quiet break for some dry weather for the middle of the week. Temperatures behind the front will be on the more mild side with Tuesday projected to be well below normal. A gradual warm up is then expected to occur through the end of the work week. Precipitation chances may begin to increase into the end of the week as models disagree a bit more. The ECMWF and Canadian keep high pressure at the surface through Friday but the GFS and ECMWF do bring an upper level disturbance toward the area Friday which may lead to chances for showers and potentially thunderstorms. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... As of 727 PM Friday... VFR conditions will be common through early tonight. Showers and thunderstorms will move into the area tonight, more likely across northern WV and Ohio. These storms will produce brief IFR/LIFR conditions, although the timing is still uncertain. Severe winds and damaging hail are also a possibility with the stronger storms. A MVFR cloud deck could form late tonight into Saturday morning over OH and northern WV. Showers and thunderstorms will continue to cause IFR restrictions on Saturday, once again more likely over northern WV and OH. Latest guidance suggests MVFR cloud deck that develops late tonight will spread southeast Saturday morning before dissipating during the afternoon hours. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY... FORECAST CONFIDENCE: Medium tonight and Saturday. ALTERNATE SCENARIOS: Timing and intensity of restrictions in showers and thunderstorms could vary. Fog could form late tonight in areas that receive rainfall if holes in the clouds develop. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE SAT 06/19/21 UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H M H H M PKB CONSISTENCY H H H H H H H H H H M M CKB CONSISTENCY H H H H H H H H H H H M AFTER 00Z SUNDAY... IFR possible in stratus and fog overnight Saturday night into Sunday morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Flash Flood Watch through Saturday morning for WVZ007>011- 016>020-027>032-039-040. OH...Flash Flood Watch through Saturday morning for OHZ066-067-075- 076-083>087. KY...Flash Flood Watch through Saturday morning for KYZ101. VA...None. && $$ SYNOPSIS...RPY/CG NEAR TERM...JSH/RPY SHORT TERM...CG LONG TERM...CG AVIATION...JSH