Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/14/21


Area Forecast Discussion
National Weather Service La Crosse WI
1030 PM CDT Sun Jun 13 2021 .SHORT TERM...(This evening through Monday) Issued at 127 PM CDT Sun Jun 13 2021 Isolated storms remain possible across north-central/central WI late today, although observational trends favor lower severe/ convective potential. GOES water vapor channels early this afternoon show a shortwave trough within NW flow dropping across the northern Great Lakes. The question continues to be whether any convection will impact north central/central WI through early evening with the shortwave/cold front. Long, straight hodographs would favor supercellular convection (as suggested by some longer-lived model updraft helicity tracks via the 12Z HREF), but weak low-level moisture/mid-level lapse rates will significantly limit instability. 12Z GRB/MPX soundings showed very shallow low-level moisture. Moisture transport is generally on the weak side ahead of the wave and will be countered by diurnal mixing. RAP indicates only a narrow axis of up to a few hundred J/kg of MLCAPE at Medford, WI with dew points in the 40s/low 50s. Other CAMs show a range in convective coverage, modulated by instability/moisture, but current dew points in the 40s/low 50s suggest moisture will be on the meager side (closer to the RAP/HRRR), limiting the convective/severe potential when combined with weak forcing. Given the shortwave trajectory, expect the higher precip chances to remain north/east of the area, but will have to monitor north-central WI for any isolated storm development late this afternoon with wind/hail potential. This risk remains highly conditional, and trends favor most parts of the area remaining dry. High pressure will build across the area into Monday with cold advection in the wake of the short wave/front ushering in slightly cooler, dry air. Highs will mostly be in the 80s on Monday with plenty of sunshine. .LONG TERM...(Monday night through Sunday) Issued at 127 PM CDT Sun Jun 13 2021 Upper ridge over the western US will dominate the weather through mid week. Highly amplified northwest flow over the upper midwest will keep temperatures and humidity on the pleasant side for mid June. For those that are hoping for some rainfall, the next time period to watch is Thursday and Thursday night. Model consensus is for the upper ridge to flatten as an upper low pushes into it across northern Canada. In this scenario, convergence along the attendant cold front could have the potential to support convection. However, there are many factors working against precipitation including limited moisture with the system and the northern track of the upper low. If the upper ridge does not flatten as quickly as the models suggest, the low would likely track farther to the north and our precipitation chances would decrease accordingly. This is reflected in the ensemble model runs which have a significant spread in solutions approaching Thursday, further reducing confidence. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1030 PM CDT Sun Jun 13 2021 Cigs: generally SKC/SCT VFR conditions expected through Tue. WX/vsby: no impacts expected. Winds: north northwest overnight with cold front sinking south of the TAF sites. KLSE more south/southeast due to decoupling...but swinging northwest by 15z or so. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...JM LONG TERM...DMD AVIATION...Rieck
Area Forecast Discussion
National Weather Service Binghamton NY
919 PM EDT Sun Jun 13 2021 .SYNOPSIS... Scattered showers and thunderstorms are expected through tonight. A few storms may produce damaging winds and heavy rain, with localized flooding possible. Scattered showers and thunderstorms continue Monday, as another disturbance drops through the region. Though a small chance of showers lingers Tuesday, drier and cooler weather is anticipated for midweek. && .NEAR TERM /THROUGH MONDAY NIGHT/... 910 PM Update... Made rather significant changes to the forecast for this evening to reflect latest radar trends. Convection has fired up along the Central Southern Tier of NY to the southern Finger Lakes along a corridor of enhanced CAPE and closer to the upper level trough. A few Severe Thunderstorm Warnings have already been issued for this part of the CWA. Meanwhile, farther south, across our Northeast PA counties, conditions have been mainly dry with just a few light showers around. Therefore adjusted PoPs to upgrade the Central Southern Tier of NY and Finger Lakes regions to likely and adjust PoPs downward farther south. Now that it is post-sunset, instability will likely be on the downward trend as the rest of this evening progresses and therefore the severe thunderstorm threat will likely decrease over the next few hours. Will let the Severe Thunderstorm Watch for the Northern Tier of PA/Wyoming Valley ride until its scheduled expiration at 02Z/10PM EDT. 640 PM Update... So far, the strongest storms in PA have stayed west of our CWA (more across Central PA), closer to the upper level trough and greater shear. Despite instability present across the Northern Tier of PA and the Wyoming Valley, the lack of enough lift has prevented much thunderstorm development up to this point. Still expecting coverage of scattered showers and thunderstorms to increase throughout this evening as the trough approaches, but the overall extent of the severe weather potential for the above mentioned areas (where a Severe Thunderstorm Watch remains in effect until 10PM) is somewhat questionable. The greatest coverage of showers and storms may not be until after sunset and by then, diurnally-driven instability will be waning. That being said, we are not making any changes to the Watch at this point and this will be re-evaluated with the next forecast update. Any storms that do develop with have the potential to bring locally heavy rainfall. In terms of tweaks to the official forecast, mainly made adjustments to PoPs to better reflect current radar trends. Otherwise, the previous discussion below remains valid. 320 PM Update... Latest RAP13 analysis shows a band of low level convergence focused over the Northern Tier of PA, though this is not readily apparent in surface obs. Instability axis extends across pretty much the same area, but continues eastward into the Catskills and Poconos, where cloud cover has eroded over the past couple of hours. Further north, rather dry air in the low levels is limiting instability despite slightly cooler air in the mid-levels -- note lower 50s dewpoints and even 47 at ITH which would be questionable if not for the 50 at Cortland. Meanwhile, and upper level trough is moving across SW Ontario, evident in satellite imagery, while a surface trough/weak cold front tries to take shape from far western NY into eastern Ohio, masked somewhat by the lake breeze downwind of Lake Erie. Expect isolated showers and thunderstorms to increase in coverage across the Northern Tier of PA, with a general eastward progression, with stronger cells perhaps curving more to the southeast as they tap into the mid-level flow. Additional thunderstorms are expected to develop along the surface trough early this evening, and will spread east into our area, including the Southern Tier and parts of the Finger Lakes where destabilization can occur. Expect several clusters of storms to be on-going by nightfall, with some heavy rain potential as storms may try to train along old leftover boundaries. The greatest risk of heavy rainfall will be over NE PA, where low- level theta-e ridging looks to lay across, nosing into the Catskills/Poconos overnight. Mid-level dry air will promote strong thunderstorm wind gusts early on, with isolated hail possible given steeper lapse rates, but as soundings become more modified/moist, heavy rain will become the primary threat. For Monday, the main upper trough will swing into southwestern Ontario, with several bands of rain and embedded thunder possible. Additional strong to severe thunderstorms can`t be ruled out again, but will be highly dependent on how convection evolves overnight into the morning hours. At this time, it appears areas east of I-81 will be most likely to recover and destabilize before the main trough swings through. 1145 AM Update... Low clouds are rapidly breaking up and are currently limited to the Catskills and NE PA, with plenty of sunshine filling in to the north and west. With strong surface heating, we could see temperatures in parts of the Mohawk Valley climb well into the middle or even upper 80s by this afternoon. Thunderstorm potential remains a challenging forecast. HRRR and other high-res models suggest weak low level convergence will develop along a line roughly from ELM-SYR with southwest flow to the west of the boundary, and backed S to SSE flow to its east, apparently influenced by differential heating on either side of the dissipating cloud layer. Meanwhile, RAP13, NAM, other models suggest moderate instability will develop across the Twin Tiers by this afternoon, with SBCAPE vales of 1000-1500 J/KG, and minimal CIN. Despite the collocation of the low level convergence and instability, many of these same models struggle to initiate convection without a larger-scale trigger. That trigger, a shortwave trough currently over Lake Huron, doesn`t look to arrive into western NY/PA until around 00Z, assuming it is being properly initialized. For now, kept at least a "Chance" PoP in the SW part of the CWA and extending E-NE along the low level convergence zone early this afternoon, but the better chances for thunderstorms may not come until later this afternoon into this evening, with a focus mainly south of the Southern Tier. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... 300 PM Update... Some patchy fog could hang around Tuesday morning, but should lift soon after sunrise. A couple of weak shortwaves and low level moisture will provide some support for a few spotty showers on Tuesday. With a few hundred J/kg of CAPE present, afternoon thunderstorms are also possible. Not much is expected for accumulations, up to a couple of tenths at best. Highs will only be in the upper 60s to mid 70s as northerly flow advects cooler air into the area. Showers and skies clear out Tuesday night as high pressure moves in. Overnight lows will fall into the 40s and 50s Sunny skies are in store for Wednesday. However, with northerly flow still present, highs will once again be in the upper 60s to mid 70s. This cooler air will provide plenty of natural AC as lows drop into the 40s Wednesday night. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... 300 PM Update... The start of the long term period will start out quiet. High temps on Thursday will be in the 70s and the lows will fall into the upper 40s and low 50s. Friday will also be fairly quiet, but the pattern begins to shift. A ridge moves through and flow becomes more southwesterly, bringing warmer air and moisture to the area. Highs will be closer to 80 on Friday. Chances for precipitation increase Friday evening as a cold front approaches the area. This cold front will bring rain showers and possibly some thunderstorms through Saturday night. Models still differ on the timing of this system with GFS still being the faster solution, so followed National Blend of Guidance (NBM) for the timing which is a little slower like the ECMWF. Sunday looks to be cooler to finish out the weekend with also a slight chance for showers with the passing of a weak system. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... Scattered showers and thunderstorms are expected tonight, especially this evening across the Twin Tiers. Right now, confidence in thunder was only high enough to include in the TAF at KBGM and KELM in two hour TEMPO groups this evening. Elsewhere, an isolated thunderstorm cannot be ruled out, but confidence is not high enough to include in the TAF just yet. Will continue to monitor this potential for potential amendments if necessary. In terms of restrictions, mainly VFR conditions early this evening will likely give way to at least Fuel Alternate ceiling restrictions overnight at all TAF sites with the exception of KSYR. Best chance for IFR conditions will be at KAVP, KBGM, and KELM. Patchy fog/mist is also possible. Conditions are expected to return to VFR by Monday afternoon, with KAVP likely being the last terminal to do so. Another round of scattered showers and thunderstorms is expected Monday afternoon, although confidence in thunder is too low at this time to include in the TAFs. This will be fine-tuned in the upcoming TAF issuances. Outlook... Monday night...Some restrictions possible with lower ceilings and/or patchy fog. Tuesday...Chance of additional showers and thunderstorms/brief restrictions, otherwise mainly VFR. Tuesday night through Friday...Mainly VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...BJG/MPH NEAR TERM...BJG/MPH SHORT TERM...BTL LONG TERM...BTL AVIATION...BJG
Area Forecast Discussion
National Weather Service Corpus Christi TX
616 PM CDT Sun Jun 13 2021 .AVIATION... VFR conditions will prevail through most of tonight. Light patchy fog and low CIGs are expected to briefly develop toward early Monday morning, leading to MVFR/IFR conditions, especially from ALI to VCT. VFR conditions will quickly resume mid morning Monday and will continue through Monday afternoon. There is a chance of showers and thunderstorms across the VCT area Monday afternoon. Winds will generally be light and variable a majority of the TAF period. && .PREV DISCUSSION... /Issued 245 PM CDT Sun Jun 13 2021/ SHORT TERM (Tonight through Monday Night)... Heat index values this afternoon are climbing into the 103 to 106 range and are expected to hold in this range for the next few hours before cooling with sunset. Surface winds are remarkably light and generally less than 5 MPH across the Coastal Bend and Victoria Crossroads. While these elevated heat index values are just a bit lower than the criteria normally used to issue a Special Weather Statement, have concerns that very light winds will only increase the heat stress that individuals experience while outdoors and have opted to issue a short statement for heat for this afternoon. Water vapor imagery this afternoon showed a small disturbance embedded in the northeast flow aloft translating down the Middle Texas coast. Despite the presence of this feature, any convection this afternoon appears to be limited by drier air over the region as visible satellite shows a rather compressed cumulus field. Some enhancement has been noted near and east of Matagorda Bay, where the sea breeze has begun to move inland. A remnant mesoscale convective vortex (MCV) was noted earlier in the day moving across Brazoria and Matagorda counties in the vicinity of this sea breeze, but has become less defined during the afternoon hours and is difficult to determine whether or not the feature still exists on satellite and surface observations. Regardless, deeper convection that it able to form along the sea breeze north of the region... aided by whatever forcing from the disturbance aloft and additional surface convergence the remnant MCV provides... may be able to propagate into the Victoria Crossroads before sunset. Have maintained low (20 percent) rain chances as a result of this potential, with the thinking for the remainder short term forecast also remaining virtually unchanged. Dry conditions will persist across the region tonight with clearing skies allowing for another round of radiation fog to develop across the Coastal Bend and Victoria Crossroads after midnight tonight. Ample near surface moisture may result in dense fog to develop, but it is interesting to note that recent HRRR runs have backed off on lower visibilities overnight. This is probably due to anticipated subsidence over the region as the disturbance aloft drops farther southwest, but with forecast soundings showing the boundary layer decoupling after midnight (limiting the potential for influence from this feature) will continue to maintain fog in the forecast. Otherwise, expect lows to bottom out in the low to mid 70s. Morning RAOBs depicted a broad upper ridge centered over New Mexico with a shortwave trough rotating around the eastern periphery of the ridge across the Red River. While the trough over Oklahoma will remain too far north and west of the region to affect sensible weather in the short term, it is expected to nudge weak surface troughs or convergence zones towards the region by Monday morning. Returning moisture and the presence of these boundaries will result in a new focus of shower and thunderstorm activity on Monday, some of which may advect towards the region from South Central or Southeast Texas as northeast flow aloft persists. This deeper moisture will also allow for slightly higher heat index values by Monday afternoon. Highs in the upper 80s to mid 90s along the coast will increase to the low 100s along the Rio Grande, allowing for most of the region to feel like it is in the 100 to 110 degree range. As the upper ridge wobble over the Four Corners region on Monday night, additional disturbances will translate across the region as flow aloft becomes more easterly. This may allow for shower and thunderstorm development to continue across the Victoria Crossroads into the early morning hours Tuesday with lows across the region in the mid to upper 70s. LONG TERM (Tuesday through Sunday)... Not much change to the long term forecast. A strong mid-level ridge will remain nearly stationary over the Four Corners region through Friday with a slight westward drift thereafter. This will keep conditions primarily dry with partly cloudy skies as a northeasterly flow persists over the area. A few sea breeze showers and thunderstorms will be possible throughout the week as a couple of weak shortwave troughs push through South Texas around the periphery of the upper ridge, and PWATs hover near 2 inches along the coast. Temperatures will be hot through mid week with heat indices ranging from 105-109 Through Wednesday then 100-105 through the rest of the week. Highs will be in the 90s for most of the area with triple digits along the Rio Grande. Lows will be in the 70s. Cannot rule out some patchy fog across the inland coastal plains during the early morning hours this week. The National Hurricane Center continues to monitor an area of low pressure over the Bay of Campeche for potential tropical development. At this time there is a 20% chance of development in the next 48 hours and a 50% chance of development in the next five days. The deterministic and ensemble models show a considerable spread and thus there remains uncertainty with regards to the structure, future path, and potential strength of this system. Residents along the Mid Texas coast should continue monitor the latest forecasts from the NHC and ensure your preparedness plans are in place. Its possible we will see increasing tides, swells and rain chances by the end of the week into next weekend. Fortunately we will be moving into an astronomical tide minimum by next weekend which should help reduce any potential coastal flood impacts. MARINE... Isolated showers and thunderstorms will be possible along the coast north and northeast of Port Aransas on Monday with the onshore flow remaining weak. A weak onshore flow will persist through Thursday night. Winds are then expected to increase to moderate out of the northeast on Friday in response to a low pressure system moving northward into the western Gulf. The National Hurricane Center indicates this system has a 50 percent chance of becoming a tropical depression in the next 5 days. Small Craft Advisory conditions may begin over the offshore waters Friday night due to increasing swells. Isolated showers and thunderstorms will be possible Tuesday through Friday, becoming scattered Friday Night through Saturday Night. Mariners should monitor the latest information from the National Hurricane Center. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 74 94 75 93 76 / 0 0 10 10 0 Victoria 75 96 75 94 74 / 10 30 20 30 10 Laredo 76 102 77 100 77 / 0 0 0 10 0 Alice 72 98 72 95 73 / 0 0 10 10 0 Rockport 76 93 77 92 77 / 0 10 10 10 0 Cotulla 77 101 77 100 77 / 0 0 10 10 0 Kingsville 72 96 74 93 74 / 0 0 10 10 0 Navy Corpus 77 90 78 90 79 / 0 0 10 10 0 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ TE/81...AVIATION
Area Forecast Discussion
National Weather Service Cheyenne WY
529 PM MDT Sun Jun 13 2021 .UPDATE... Issued at 314 PM MDT Sun Jun 13 2021 Severe Thunderstorm Watch 268 has been issued for southeast Wyoming and Nebraska Panhandle through 04Z tonight. Updates have been sent. && .SHORT TERM...(This evening through Monday) Issued at 240 PM MDT Sun Jun 13 2021 Forecast challenges deal with severe thunderstorms today. Currently...thunderstorms developing along the Laramie Range this afternoon. Surface trough lays from near Cheyenne to Torrington with moist southeasterly upslope flow in the lower layers. Cold front being analyzed across central South Dakota back into northeastern Wyoming. SPC Mesoanalysis showing EMC RAP surface based CAPE around 5000 J/KG out in the Panhandle and around 2500 J/KG where the storms are forming on the Laramie Range. Still some small capping across southeast Wyoming with around 50 J/KG convective inhibition. Main limiting factor right now is lack of shear. Later this afternoon...northern front drops south into the northern Panhandle and Converse County in east central Wyoming. Sfc to 6km shear increases to 35kts across the northern Panhandle to around 50kts down here near Cheyenne. HRRR and NAMNEST short term guidance forecasting showers blossoming along the front as it slowly drops south southwestward into the southern Panhandle and southeast Wyoming plains. Could be a long show tonight as both models continue showers and storms through 09Z. SPC showing a Day 2 Marginal Risk area for the Nebraska Panhandle for Monday afternoon. Latest guidance showing no PoPs over that area for Monday. But with dewpoints in the 60s...surface boundary in the Panhandle and a weak upper southwest dropping shortwave...decided to add low chance PoPs for the Panhandle. and .LONG TERM...(Monday night through Saturday) Issued at 323 AM MDT Sun Jun 13 2021 Monday, the moisture sticks around the Nebraska panhandle with PWATs around 1.00 in through the afternoon. Daytime heating will still be strong with the upper-level ridge holding strong over northwest Wyoming, so the panhandle is still conducive to thunderstorms, but confidence is lower for Monday`s convection. Tuesday, the ridge begins to erode, turning our winds back to westerly/southwesterly, advecting warmer, drier air into southeast Wyoming and western Nebraska. Afternoon highs for Tuesday and Wednesday are in the 90s to 100 degrees for some areas with humidities dropping to the teens and lower 20s. Winds should remain between 5 and 15 knots, but with the temperatures being so high and the air being so dry, there is still elevated fire weather conditions. Finally Thursday we begin to see a downward trend in temperatures as winds turn northwesterly. Afternoon highs are still expected to be in the 80s to lower 90s through the weekend though, with overnight lows in the 50s and 60s. Next chance of precipitation after Monday will be Friday afternoon. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 525 PM MDT Sun Jun 13 2021 Wyoming TAFS...VFR. Thunderstorms in the vicinity at Cheyenne until 03Z. Wind gusts to 30 knots at Laramie and Cheyenne until 03Z, then to 23 knots at all terminals after 15Z Monday. Nebraska TAFS...VFR, except for occasional MVFR and wind gusts to 45 knots in thunderstorms until 02Z at Scottsbluff. Thunderstorms in the vicinity at all terminals until 05Z. Wind gusts to 26 knots until 05Z, then to 24 knots after 15Z Monday. && .FIRE WEATHER... Issued at 240 PM MDT Sun Jun 13 2021 High pressure over the Rockies will keep temperatures above normal and very dry humidity over the next several days. Increasingly warmer temperatures and single digit afternoon humidities from the Laramie Range west. Until fuels are turned over to YES on rapid fire spread...fire weather conditions will remain below critical levels. A windy day expected Wednesday into Thursday across Carbon and Albany Counties....with afternoon humidity in the single digits. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ UPDATE...GCC SHORT TERM...GCC LONG TERM...LK AVIATION...RUBIN FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Duluth MN
819 PM CDT Sun Jun 13 2021 .DISCUSSION...(This evening through Saturday) Issued at 431 PM CDT Sun Jun 13 2021 Summary: Showers and thunderstorm chances continue this evening for the Arrowhead, northwest Wisconsin, and the I-35 Corridor. Temps trend cooler Monday and Tuesday, but remain a few degrees above normal. Warmer temperatures return for Wednesday and Thursday along with a few more chances of rain and thunderstorms. Temperatures for Friday through next weekend are expected to be either side of normal, a welcome break from the recent heat with highs in the upper 60s to upper 70s. Showers and thunderstorms remain in the picture this evening for the Arrowhead, northwest Wisconsin, and the I-35 corridor. Surface low pressure was centered near Brainerd late this afternoon with a convective mesohigh over the Arrowhead. These features will both move eastward with time tonight. As the low approaches northwest Wisconsin, low-level convergence will increase along the combination lake breeze and outflow boundary from this mornings storms. Forecast and observed cloud bases in the warm sector are around 8-10 kft, so we need to provide a considerable amount of lift before we can realize the meager MLCAPE available. SPC mesoanalysis, RAP, and HRRR forecasts suggest any storms which develop will have 300-800 J/kg to work with. There is considerable dry air in the mid-levels over the warm sector which will cause dry air entrainment and further suppress convection initially. Should storms develop, additional convection along resultant outflow boundaries should sustain storms through early evening. Deep layer 0-6 km shear on the order of 70 kts and effective shear of 40 to 60 knots in addition to 500 mb flow of 55 to 60 knots should provide a fast storm motion toward the southeast. Long, nearly straight hodographs suggest damaging winds and large hail will be the primary risk with storms initially. Should a storm form on the lake breeze over Carlton, Pine, or southern Douglas counties, the storm motion and orientation of the boundary may support a brief tornado risk. However, high cloud bases and meager instability discount this potential. It seems the tornado risk is non-zero, but probably less than 1 percent. Over the Arrowhead widespread convection will continue into this evening associated with the mid-level forcing closer to the upper- low and shortwave trough. A few wind gusts of 45 to 55 mph are not out of the question with that convection, but the hail threat is near-zero. Another shortwave trough farther upstream into northwest Ontario may bring a few showers and storms back to the International Border area and the Arrowhead tonight. Storms will weaken with time with the loss of daytime heating tonight. Mid and upper-level ridging over the Northern Plains and the Rockies will keep Minnesota and Wisconsin in northwest flow aloft. Another shortwave trough will dive southward out of Ontario Monday and may bring a few sprinkles or light rain showers to the Arrowhead and northwest Wisconsin. Temperatures Monday and Tuesday will trend a little cooler, but still several degrees above normal. Warmer temperatures and rain chances return to the forecast Wednesday and Thursday. A closed low is expected to move over the northern Prairies and into northwest Ontario Friday and Saturday with a lobe of much cooler 850 mb air. Temperatures will trend cooler Friday through next weekend and will be either side of normal. With the cold air aloft, there will be chances of showers and thunderstorms each day. Timing differences and the track of the upper low preclude a mention of precip in the forecast until Sunday afternoon. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 643 PM CDT Sun Jun 13 2021 Surface low pressure was in west central Wisconsin this evening and will move southeast tonight. A few thunderstorms were occurring over northwest to north-central Wisconsin. Northwest flow aloft was sending a shortwave southeast and it along with a surface trough were producing showers and storms near the International Border. The storms will last another 2 to maybe 4 hours before they dissipate. A strong storm is possible both in northern Wisconsin which has much stronger deep layer shear but but is weaker on instability and in far northeast Minnesota which will have a bit higher instability but lower shear. For the TAFs, we expect them to remain dry through the period along with VFR conditions. There will be a cumulus field that develops over parts of the Northland Monday, mostly widespread in far northeast Minnesota. A few showers could develop as well there. Gusty winds this evening will diminish tonight then ramp up again on Monday as deep mixing is expected. && .MARINE... Issued at 820 PM CDT Sun Jun 13 2021 The strong northeast winds have quickly diminished this evening. Winds will gradually become westerly overnight, from 5 to 15 knots with a few gusts to 20 knots. There may still be an isolated thunderstorm this evening, most likely between Grand Portage and Silver Bay. The main threat will be lightning. Winds will start out west to northwest on Monday then veer north to northeast by early evening. Speeds will be at or less than 15 knots except for a few higher gusts. North to northeast winds will continue Monday night less than 15 knots. T && .PRELIMINARY POINT TEMPS/POPS... DLH 54 79 51 74 / 10 0 0 0 INL 51 77 47 79 / 10 0 0 0 BRD 55 84 52 81 / 0 0 0 0 HYR 51 81 50 77 / 40 10 10 0 ASX 52 78 48 71 / 30 10 10 0 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...None. && $$ DISCUSSION...Huyck AVIATION...Melde MARINE...Melde
Area Forecast Discussion
National Weather Service Grand Rapids MI
946 PM EDT Sun Jun 13 2021 LATEST UPDATE... Update .SYNOPSIS... Issued at 318 PM EDT Sun Jun 13 2021 - Chance of rain tonight then cooler and less humid through Thursday - Chance of showers/thunderstorms late week && .UPDATE... Issued at 946 PM EDT Sun Jun 13 2021 I have increased the chance for rain over most of the CWA tonight as a result of recent radar loop, IR image loops and some common sense meteorology. The short story is we have a rather strong and quickly digging upper level system. The axis of the polar jet core (we get into the left exit region of the jet) drops nearly due south overnight. In response to that the low level jet really strengthens overnight. By 5 am we have 35 to 40 knots on the low level jet amid at Holland Michigan. There is strong speed convergence west of US-131. Given this under the jet core exit region I have to believe there will be a lot of dynamic lift going on. The current radar images show a bowing band of thunderstorms from the Door Peninsula to near Traverse City. The HRRR does not have any forecast echos that far south at this time. However the 12z HREF did. There is strong deep layer shear, the 6km shear is forecasting between 50 and 70 knots of shear at 5 am over this same area. The down side is the cape is feeble. Still with all those dynamics I think we can still see some convection (through fast moving) come farther south than previously through. Over our north central CWA I have near conditional pops tonight (hard to believe it would not rain there). Between I-96 and Route 20 I have likely pop and high chance. There is some dry air below the cloud base, so gusty winds are possible as these storms move through. && .DISCUSSION...(This evening through next Sunday) Issued at 318 PM EDT Sun Jun 13 2021 - Chance of rain tonight then cooler and less humid through Thursday Shortwave trough coming over the western ridge will serve to amplify the flow across the CONUS with height falls across the Great Lakes and the welcome return of cooler and drier air through much of this week. Dew points drop through the 50s on Monday and all the way down to the 30s by Wednesday, when morning lows could also tumble into 30s in the cold spots like Leota, with lows in the 40s elsewhere. - Chance of showers/thunderstorms late week Another shortwave trough tops the western ridge and pushes a sfc cold front through on Thursday night into Friday bringing the chance of showers and thunderstorms. Although it is early to pin down the specifics, there are signals that strong to severe storms may be possible despite the late night/early morning timing. Strong warm advection and moisture advection/pooling ahead of the front along with shear profiles progged to be 35 to 40 knots means there is potential for a progressive derecho tracking near or just south of Lower Michigan. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 723 PM EDT Sun Jun 13 2021 A weak area of low pressure will drop southeast across the state tonight and produce a few showers after midnight...perhaps an isolated thunderstorm. Moisture is lacking in this system and so we don`t anticipate anything other than VFR conditions through the period. && .MARINE... Issued at 318 PM EDT Sun Jun 13 2021 Low chance of thunderstorms tonight north of Grand Haven then northerly winds around 10 to 20 knots the next few days with waves expected to remain less than 4 feet. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...WDM SYNOPSIS...Ostuno DISCUSSION...Ostuno AVIATION...04 MARINE...Ostuno
Area Forecast Discussion
National Weather Service Jacksonville FL
846 PM EDT Sun Jun 13 2021 .UPDATE... Evening convection weakening over the area as airmass stabilizes after earlier strong storms that produced isolated hail and flooding. Upper trough axis over the area and backdoor front moving sw into se Ga will keep scattered showers and isolated thunderstorms going until at least midnight. Upper trough will continue to drift se over ne Fl on Monday with scattered afternoon storms expected more likely over ne Fl and coastal se Ga where higher instability and moisture will exist. && .PREV DISCUSSION [720 PM EDT]... .Short Term.../through Tuesday/... Stalled frontal boundary will persist across area this afternoon, and will be a focus for diurnally driven convection. In addition the sea breezes will also provide sources for convergence. Expect greatest coverage of convective activity across NE FL due to location of frontal boundary. Due to the expected slow movement of convection, periods of heavy rainfall anticipated, especially across NE FL. The boundary will dissipate overnight, with convection diminishing around midnight. Lower chances for convection expected for Monday, with this activity largely driven by diurnal instability, and east coast sea breeze interactions. Another cold front will move into southeastern US Tuesday providing a prevailing flow from the southwest. This will keep the east coast sea breeze from pushing inland. Convection will be limited in coverage again Tuesday, with mainly diurnally driven activity. Overnight lows will be near normal this period. Highs will trend below normal on Monday, then near normal on Tuesday. .Long Term.../Tuesday night through Sunday/... Cold frontal boundary will sink south across forecast area Tuesday night, becoming stalled near the GA/FL line Wednesday, where it will linger through Wednesday night. The front will dissipate during the day Thursday. Better moisture will be south of the boundary, so best convective focus over NE FL through Thursday. High pressure will be to the east, with troughing to the north late in the week through the weekend, with isolated to scattered convection expected. .AVIATION...[Through 00Z Tuesday] Convection weakening this evening across NE Fl/SE Ga and will likely linger till around midnight as the well performing HRRR model indicates. Instability has weakened so expect mostly showers with isolated thunder possible. VFR conditions will prevail overnight with chance of MVFR conditions in shower activity. Have VCTS after 17z Monday as scattered afternoon storms develop. .Marine... A frontal boundary will remain stalled over region this afternoon, and dissipate overnight. Another cold front will move into southeastern US Tuesday, then stall across area Tuesday night through Wednesday night, before dissipating Thursday. The region will be between high pressure to the east and a trough of low pressure to the north late in the week through the weekend. Rip Currents: SE GA: Low through Monday NE FL: Low through Monday && .PRELIMINARY POINT TEMPS/POPS... AMG 70 89 72 94 71 / 20 20 10 30 10 SSI 73 81 75 90 76 / 40 30 20 30 10 JAX 71 85 72 92 72 / 50 40 20 40 20 SGJ 71 83 72 89 74 / 50 50 20 40 20 GNV 71 88 71 88 72 / 50 50 40 50 30 OCF 71 88 72 87 74 / 40 50 40 40 30 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. &&
Area Forecast Discussion
National Weather Service North Platte NE
640 PM CDT Sun Jun 13 2021 .SHORT TERM...(This evening through Monday night) Issued at 323 PM CDT Sun Jun 13 2021 A weak frontal boundary across SD should settle into the White River basin this afternoon and this evening acting as a focus for storm development across wrn and ncntl Nebraska tonight. The ongoing convection across cntl SD should help push the front south, perhaps to near the SD/Neb border. Satellite also suggests a very weak upper level disturbance across ncntl Colo/wrn WY which is expected to set off storm activity on the Laramie Range and perhaps the Pine Ridge. Winds aloft are weak at 20 to 25 kts but the bulk effective shear should increase to 30 to 35 kts given the low level inflow across the Panhandle. SPC suggested a slight or 15% severe weather chance and the primary storm modes are large hail and wind damage early which become wind damage with the formation of a healthy cold pool later this evening. POPs for the forecast tonight are mostly 20 to 30 percent with 40 percent across northwest Nebraska. This might be conservative but storm activity will have to overcome a 14C 700mb cap across the Panhandle and the RAP model would suggest no POP at all because of the cap. The temperature forecast leans on the guidance blend plus bias correction plus a couple of degrees across swrn Nebraska. The convection tonight should help pull the cold front south into ncntl Nebraska providing a modest cool down Monday. Highs around 90 are in place across ncntl Nebraska Monday with mid 90s across swrn Nebraska. Rain chances Monday night have been dismissed by most models with just the SREF showing development in the Panhandle late Monday. The models are in good agreement building a fairly strong h700mb ridge across wrn Nebraska which should produce subsidence and no obvious trigger is shown aloft by the models. Temperatures aloft at h700mb are around 14C presenting a formidable cap leaving just a weak frontal boundary near the Black Hills and of course, the Laramie range for focus and storm development. Nonetheless, SPC suggested storms may form across the Panhandle Monday evening and the forecast carries an isolated POP for this reason. .LONG TERM...(Tuesday through Sunday) Issued at 323 PM CDT Sun Jun 13 2021 There is little change in the extended forecast today. The models are in very good agreement amplifying the subtropical ridge across NM north into Nebraska this week- Wednesday will be the warmest day. The upper level ridge will flatten Thursday allowing a Pacific cold front to move through Nebraska with cooler weather to follow. The models continue to show h700mb temperatures rising to near 17C Wednesday...about a 3C bump above Tuesday`s readings. Highs in the 90s are in place Tuesday which warm a few degrees Wednesday. Dew points in the lower 60s shown by the model consensus generate heat indices above 100F and later forecasts at some point will likely include a heat advisory. Isolated POPs are in place at times Wednesday night through Sunday but later forecast may well have to increase these chances. A stationary front may set up across Nebraska and this would certainly provide an excellent focus for storm development, especially given the increase in winds aloft to around 40kt. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 632 PM CDT Sun Jun 13 2021 Scattered thunderstorms will develop and move southeast into western and portions of north central Nebraska tonight. Chances are not real high that they will directly impact either the LBF or VTN sites, but it is possible and a VCTS has been included in the terminal forecast. Otherwise VFR conditions will prevail outside of any thunderstorm activity. Winds will generally be 10 kts or less but will be stronger around any thunderstorm activity. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION...Taylor
Area Forecast Discussion
National Weather Service Pueblo CO
901 PM MDT Sun Jun 13 2021 .UPDATE... Issued at 847 PM MDT Sun Jun 13 2021 Updated to end thunderstorm chances for this evening. A few cells have popped up on the north side of the Palmer Divide, but are having a hard time sustaining themselves as they drop southeast. At this time, it does not appear they will make it into northern El Paso County. Mozley UPDATE Issued at 550 PM MDT Sun Jun 13 2021 Updated the precipitation chances based on the latest satellite, radar and guidance. The two areas of concern continue to be the Palmer Divide and Raton Mesa region. Isolated thunderstorms continue to pop up off Pikes Peak, and then dissipate as they shift eastward into El Paso County. MLCAPE values are still upwards of 1500 j/kg, however, there is quite a bit of CIN across the region, likely limiting the eastward extent. That being said, if a storm can get going, there is more than enough instability and shear for strong updrafts that could produce up to 1.5 inch hail and 60 mph winds. Down south off the Raton, there is much less certainty. Moisture is more limited, and MLCAPE under 1000 j/kg and quite a bit of CIN. An isolated strong to severe storm may also be possible over this area. Thunderstorms should dissipate with sunset, with dry conditions expected after 8 PM or so. Mozley && .SHORT TERM...(This evening through Monday) Issued at 251 PM MDT Sun Jun 13 2021 Currently... A few small thunderstorms have fired off in El Paso County, while some spotty cumulus clouds can be seen on visible satellite across the I-25 corridor. Dewpoints near the Palmer Divide are still near 60, so things are still a fair bit more humid than some models suggested. Will be keeping a close eye on convective activity over the next few hours... The main influence for today`s setup will be the shortwave energy traveling through the upper-level ridge over our area this afternoon through tomorrow morning. These conditions will provide some synoptic scale ascent, while surface flow is expected to be similar to yesterday. Flow at the surface will mainly be from the east- southeast, providing moisture, while flow at the mid-levels will be more westerly, providing some directional shear and advecting dry air aloft, serving to increase mid-level lapse rates. The main difference in the setup from yesterday is that the best flow and moisture will be centered north of highway 50, and our main areas of interest for severe potential will be Teller, El Paso, and possibly eastern Fremont and northern Pueblo Counties. Severe Threats... Given proper orographics and surface flow, the Raton Mesa and Palmer Divide will be the two main areas to watch this afternoon-evening. For the Palmer, short-term models are resolving 2500-3000 J/kg of CAPE and 30-plus knots of bulk shear near Colorado springs, which makes sense given that dewpoints have been in the low-60s since 9AM. A few small thunderstorms have fired off of Pikes Peak and drifted into El Paso County, but nothing severe has been noted yet. Models suggest more storms should fire within the next few hours, lasting through 6-7PM. Looking at forecast soundings, there are still some decent dewpoint depressions expected near the surface, and with inverted-V soundings present at several locations and moisture seemingly more high-based, today`s primary threat will likely be 60- 70 mph wind gusts and hail up to 1.5 inches. Similar to yesterday, LCLs are on the high side over the I-25 corridor, and given the high- based moisture the chance of a tornado is fairly low, although if one were to happen it would be over the Palmer Divide where LCLs are the lowest. The Raton Mesa overall is looking a bit less favorable for severe weather today. Models are resolving between 700-1500 J/kg of CAPE and around 30 knots of bulk shear. However, moisture does not seem to be nearly as bountiful and LCLs are closer to 10 kft in most places. However, should a storm overcome these limitations and fire, it would likely occur between 4-6PM near Trinidad, with 60mph wind gusts and 1-1.5 inch hail possible. The threat of tornadoes in that area is near zero. Finally, a few storms could also fire off the Wet Mountains a bit later in the afternoon as well. Models are in disagreement on this, but given the ambient moisture and CAPE in the area, the possibility cannot be ruled out. However, there is low confidence that these thunderstorms would be able to reach severe status. Forecast Confidence... Over the last several days, forecast models have been handling convective activity fairly poorly. The HRRR has had the tendency to overmix the atmosphere, resulting in incredibly dry and precipitation-free environments. Overall, the NAM and NAM Nest, as well as ensemble solutions, seem to be handling these situations more appropriately. This reveals several potential solutions for this type of situation; where there is ample moisture and instability, but it is high-based. Additionally, there is a notable cap over the eastern plains that should prevent convection entirely, and although shear is sufficient, overall there is fairly weak large- scale forcing to help thunderstorms along. If storms manage to overcome these obstacles, they tend to be stronger to severe, but some models tend to lean towards solutions where the inhibiting factors win out. Given recent trends over the last several days, combined with increased confidence in a more moisture-rich environment than models suggest (which tend to run a bit dry, anyways), forecast confidence in convection over Teller and El Paso Counties this afternoon-evening is moderately high. Confidence on the Raton Mesa convection is moderate, but still possible, while the confidence on convection coming off the Wet Mountains into Pueblo County is low. Even though we have higher confidence in storms on and near the Palmer Divide today, the strength and extent of the storms will depend on how soon convection can overcome these limiting factors, and will have to be closely monitored closer to initiation time. Storm motion today will also be tricky, as storms have tended to be very slow-moving the last 48 hours, which models capture especially poorly. Given the mean flow, storms moving to the northeast through our area of interest is most likely at this time, although propagation of updrafts will likely differ storm to storm. Monday... Moisture is still expected in excess over the far eastern plains on Monday, and with daytime heating in no short supply under the upper- ridge, another round of convective storms is anticipated for the afternoon-evening hours. However, like today, there will be a cap in place over most of the area, so confidence in this outcome is still in flux. The best environment for storms will be to our east, where there is more CAPE and less instability. However, a few storms could still fire off the southern Sangres tomorrow before moving east into better air. Otherwise... Outside of the general severe threat, temperatures today and tomorrow will be hot once again, hitting mid-high 90s over most of the area, with near-record breaking temperatures expected in several places. Outside of convective areas, there will just be a few clouds around, mostly sunny, which will assist in the daytime heating, and winds should stay from a generally southeast direction and slightly gusty in the afternoon hours. .LONG TERM...(Monday night through Sunday) Issued at 251 PM MDT Sun Jun 13 2021 ...Hot with isolated mountain thunderstorms at times...a potential uptick in thunderstorms still advertised for late week into next weekend... Upper high stays locked in across the Rockies and 4 Corners region through mid week with low levels drying out in and near the mountains. Mid and high based moisture will gradually increase within the upper high. This will support isolated afternoon and evening thunderstorms over and near the mountains both Tuesday and Wednesday. Inverted V soundings suggest primary storm risks will be lightning and gusty outflow winds but only spotty light rainfall. Meanwhile, high temperatures will climb to record to near record values both days. Energy moving through southern Canada and the northern U.S Rockies will eventually send a cold front into the southeast plains...mostly likely in the Thursday night/Friday time frame with EC leaning towards the later side. With moisture still cycling through the upper high across CO, the mountains will see isolated to scattered thunderstorms each day with a better chance for some spotty wetting rains as surface dew points come up. The plains will see an uptick in thunderstorms Friday into next weekend with the possibility of strong to severe thunderstorms on Friday or Saturday if sufficient low level moisture advects back westward. Otherwise with another day of record to near record heat on Thursday, temperatures will be dropping back closer to climatological averages...though still slightly on the high side. -KT && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 251 PM MDT Sun Jun 13 2021 VFR conditions expected over KALS, KCOS and KPUB over the next 24 hours. Winds this afternoon will be gusty up to around 25 mph, from the southeast at KALS and the southeast at KCOS and KPUB. There is a chance that thunderstorms could develop near KCOS and KPUB after about 22Z this afternoon, with confidence at KCOS being much higher than KPUB. However, exact storm placement will be tricky today, so left KCOS at VCTS for now. Winds will weaken after nightfall and become diurnally driven. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MOZLEY SHORT TERM...GARBEROGLIO LONG TERM...KT AVIATION...GARBEROGLIO
Area Forecast Discussion
National Weather Service Blacksburg VA
1029 PM EDT Sun Jun 13 2021 .SYNOPSIS... A front enters the area late tonight, pushing to the coast by Tuesday. Drier air works in behind this system for much of the coming week. The next chance of showers and thunderstorms returns for next weekend. && .NEAR TERM /THROUGH MONDAY/... As of 1025 PM EDT Sunday... Bowing line of storms continues heading south through the south-central portions of the forecast area. This line is expected to continue heading south, and trend weaker in time. Most of the precipitation behind this feature is light rain that will continue for an hour or two behind the exiting line. Little if any rain is expected across the area by 200 AM Monday. Fog is expected to develop overnight. Some areas could be locally dense. As of 630 PM EDT Sunday... Small adjustments made to thunderstorm arrival... The forecast on a whole will not be changed a great deal. We are still expecting the ongoing thunderstorm activity southeast of Covington to head southeast, and storms across central WV to continue heading southeast into the Watch area. Have made minor adjustments to the hourly grids regarding the timing of the best chances of stronger storms entering the Watch area. As of 500 PM EDT Sunday... Severe Thunderstorm Watch in effect through 10PM for northwest part of the forecast area... Forecast update in the near term reflects a more robust coverage of showers and storms around the Lexington region over the next couple of hours. Looking ahead into the evening hours, we will become more concerned with activity that is currently across northern sections of West Virginia. Showers and storms are expected to head south following an instability axis and arrive within the new Severe Thunderstorm Watch area with in the 7pm to 9pm time frame, then progress southeast into the region. The greatest severe threat will be damaging winds. Also, locations that receive multiple rounds of heavy rain producing showers or thunderstorms could be a candidate for localized flooding or flash flooding. We will continue to monitor for both severe and flooding threats. As of 145 PM EDT Sunday... Threat of severe storms, some heavy rain along a line this afternoon/evening... High-res convective allowing models are somewhat different on timing/strength of the convective clusters that extend eastern Ohio, northern WV into the Shenandoah Valley north of Staunton this afternoon. The visible satellite shows limited vertical development in the cu field in our forecast area. This shows that the 12z HREF/Nested NAM and 16z RAP are overdone on convection as they were all showing storms firing up in the Alleghanys from Greenbrier to Bath by now. The 16z HRRR seems to have a better handle on what is occurring and will lean toward its solution this afternoon, though the others have the same flavor on lining up convection further north and showing a scattered to broken line of storms moving south into our Alleghany Highlands/Greenbrier Valley area east toward the Blue Ridge between 19z-22z, then shifting to the Roanoke/New River Valleys between 22- 01z, in two clusters, one pre-frontal the other more along an upper wave. Instability this afternoon is high but airmass is "drier" over us with pwats of 1 to 1.3 inches. SBCAPEs are running above 2000 J/kg in the mountains, and even higher over KY where temperatures are warmer. Low cloud cover has slowed the destabilization further east, but DCAPES are higher in the 1000-1300 J/kg range. With instability present/available, am concerned we could at least see some potential for stronger winds across our northern CWA later this afternoon, though the better shear exists further north. As we head through the evening, expect some weakening as this line moves south through the NRV and Mountain Empire east to the piedmont with models showing convection breaking up and ending late, though some models are still showing lingering showers into the overnight. Will keep pops in the likely range north of I-64 this afternoon, to chance pops along/west of the Blue Ridge, as a few showers/storms could fire along the ridges after 4pm. By dusk ramp trying to time the line of convection but also showing areal coverage lessening, so will have likely pops from the Mountain Empire through the New and Roanoke Valleys, northeast toward Lynchburg, tailing off the low chance along/south of the Va/NC border. As the vort associated with convection pushes off to the southeast overnight, look for some clearing, but also have potential for low clouds/fog again, especially where it rains, but confidence is low on this. Will have more clouds in WV and the piedmont, with less in along the Blue Ridge by dawn Monday with fog most everywhere in the 2 to 5 mile visby range. Monday should be drier, as lower dewpoints at least work to the mountains after frontal passage. There looks to be another wave along the front moving across central Virginia Monday afternoon, but overall a west-northwest flow increasing aloft to dry the airmass out, so keeping any slight chance pops east of Lynchburg to Danville line, with most places seeing plenty of sunshine but staying warm with highs in the lower 80s mountains to near 90 east. Forecast confidence is high on threat of showers/storms through this evening, though average on how high pops to go and how far south this line makes it. Average confidence on fog/low clouds late tonight but high confidence on a drier and sunnier Monday. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 200 PM EDT Sunday... Shower chances trend down as high pressure builds in... An upper trough sets up over much of the east coast of the CONUS, anchored on a cutoff upper low in southeastern Canada. This will advect some cooler, drier air into the area and help decrease the chances of precip through the middle of the week. In addition, higher surface pressure begins to settle in, arriving from the midwest. The center of the surface high will be near OH and MI by Wednesday night. The high pressure will also help to suppress showers, but the possibility for some isolated showers exists through Wednesday afternoon/evening, especially over the mountains, but most will remain dry. With largely clear skies and a bit of a drier air mass, expecting diurnal temperature swings to be 20+ degrees as there is no cover to block insolation during the day, no showers to cool daytime temps, and little cover to prevent radiative cooling at night. This will be more evident towards the mid-week; by Wednesday night, expecting lows to drop into the 40s west of the Blue Ridge, 50s east. Highs in this portion of the forecast will generally be in the mid 70s west, mid 80s east. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 200 PM EDT Sunday... Dry conditions last through Friday, but an approaching cold front ends the calm weather this weekend... High surface pressure will keep precip at bay through Friday. Meanwhile a surface low moves through southern Canada and towards the Great Lakes. That low has an associated cold front trailing below it that approaches us by Saturday morning. The surface high pressure that had been over us will slide off the coast and synoptic flow will turn to the south/southwest ahead of the front. This will warm things up for the weekend. Pre- frontal showers will begin forming by Saturday afternoon and should continue through Sunday. Temperatures will start around or just below normal for the season and rise to a few degrees above towards the end of the forecast period. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... As of 715 PM EDT Sunday... Strong to severe thunderstorms will be impacting at least TAF sites KLYH, KROA, KLWB, KBLF, and perhaps KBCB through 02Z/10PM. Variable wind speeds with gusts nearing 50kts are likely in and around each of these airports as the storms move through. Also, anticipate quick changes and both ceiling height and visibility thanks to these storms as well. It`s a bit more uncertain if KDAN will see any substantial activity, but there likely will be at least scattered showers near KDAN around 01Z-03Z/9PM-11PM. Once the precipitation clears, look for areas to trend towards decreasing visibility as light fog develops. Most areas with fog will be in MVFR range, but pockets of IFR or lower are possible, especially in the river valleys and where the heaviest rain falls this evening. On Monday, drier air will work its way into the region with conditions quickly improving to VFR by mid-morning, and remaining that way through the day. Confidence in the above aviation scenario is moderate to high. The biggest question will be the next few hours with the impacts of the strong storms moving through the area. Extended Aviation Discussion... There is a low chance of thunderstorms Tuesday afternoon in the mountains. Otherwise mainly VFR into Friday outside of any late night fog in the mountains with high pressure settling in over the region. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS/WP NEAR TERM...DS/WP SHORT TERM...VFJ LONG TERM...VFJ AVIATION...DS/WP
...Update to aviation forecast discussion...

.DISCUSSION... Issued at 229 PM CDT Sun Jun 13 2021 Upper level ridging remained centered over the southwestern U.S. per the 19Z water vapor imagery with the ridge axis extending into the northern Rockies. A closed upper low was off the Pacific Northwest coast, and an MCV was noted over southwestern OK generated from last night`s convection. At the surface, high pressure continued to nose into northeast KS providing some relatively dry air and light winds. The low level moisture axis was shifted west over south central and western KS as a result. For tonight quiet weather should continue due to a lack of forcing for vertical motion and general subsidence within the upper ridge axis. With clear skies and light winds, lows are expected to fall into the lower and middle 60s. Chances for ground fog look pretty small since afternoon dewpoints have already mixed out into the middle and upper 50s. Monday could see another MCV this time move across northeast Kansas from convection that has developed over SD. The 15Z RAP shows a nice compact vort max moving through the area during the afternoon and other 12Z guidance also indicates this potential to varying degrees. While the RAP develops isolated showers, the NAM and GFS fail to do so because of a dryer airmass and less instability. And the RAP doesn`t get much support from the HREF, although the 12Z HRRR has some isolated precip moving into north central KS early in the afternoon. Much of the larger scale models keep things dry except for the GFS which waits for the MCV to pass before developing storms. This doesn`t make much sense and was not given much weight in the forecast. So with the majority of guidance keeping a dry forecast, have POPs at 10 percent across north central KS where there could be just enough moisture as the MCV passes for an isolated storm to pop up. Highs Monday look to be in the lower and middle 90s as models warm the airmass slightly. For Tuesday through Thursday, the main story is the heat building into the forecast area. Models show good warming at 925 for Wednesday and Thursday with western parts of the forecast area potentially hitting triple digits. For now the National blend of models keep the higher dewpoints southeast of the area with mixing in the afternoon lowering the moisture content. This keeps apparent temps below 105 Thursday afternoon. But this will be something to keep an eye on. Models prog a boundary moving into the area and hanging up across the region Thursday night and through next weekend. This coincides with the upper ridge breaking down to allow the front this far south. So the good news is there should be a cooling trend for highs even if there remains some differences in the location of the boundary. But the 12Z ECMWF has started to show the boundary moving into the forecast area. This may provide a focus for showers and storms even though the better westerlies look to remain north of the forecast area. So the forecast has some small POPs sprinkled throughout the forecast for the end of the week and the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 617 PM CDT Sun Jun 13 2021 High pressure overhead will keep VFR conditions with clear skies and light to calm winds overnight, remaining light through the day tomorrow. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...Wolters AVIATION...Picha