Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/15/21

Area Forecast Discussion
National Weather Service La Crosse WI
1041 PM CDT Fri May 14 2021 .SHORT TERM...(This evening through Saturday) Issued at 252 PM CDT Fri May 14 2021 A weak 500mb shortwave was generating a loosely organized, north- south oriented band of very light showers/sprinkles from eastern MN down through central IA early this afternoon. Very dry air in the low levels per regional observed soundings and RAP guidance has been limiting how much rain can make it to the surface, but indeed some stations just upstream have been reporting light rain at times - surprising, considering the nearly 30 degree dewpoint depression in place. This large T-Td spread has also led to very low RH in the teens to 20s, but southerly winds have been in check for the most part from a fire weather standpoint with only occasional gusts around 20 mph. The deep, dry mixing and somewhat slower cloud progression has allowed temperatures to climb a bit higher than anticipated, especially east of the Mississippi River where 1 PM readings were in the mid 60s to lower 70s. Any rain that manifests west of the Mississippi this afternoon should be primarily just sprinkles. Forecast soundings start to moisten up in the low levels this evening as mixing diminishes, which will lend itself to a greater chance of steadier rainfall getting down to the surface tonight. Not only that, but a reinforcing shortwave will drop through the region tonight to offer slightly better forcing. That said, we`re not looking at any substantial rainfall potential...those that get any rain will be lucky if they receive 0.1 inch. Nudged low temps upward a bit given widespread cloud cover and weak warm advection tonight. Lows will range from 40s to around 50. The shortwave will be overhead around daybreak Saturday, slowly progressing eastward through the day and taking better precip chances with it. As cloud cover thins a bit from the west, will have to watch for a small amount of instability building ahead of yet another weak wave of energy progged to drop into the area in the afternoon. This feature will be accompanied by a wind shift near the surface that should provide enough low-level convergence and instability to generate a broken line of showers and perhaps a few thunderstorms. Deep layer shear overhead remains weak through late afternoon, so not expecting strong storms. Highs Saturday in the 60s to near 70. .LONG TERM...(Saturday night through Friday) Issued at 252 PM CDT Fri May 14 2021 Rain chances diminish with loss of heating and shortwave energy Saturday evening, with much of Sunday looking dry. Another shortwave passes through Sunday evening into Monday morning, but a second area of shortwave energy moving south of the area looks to focus the better moisture transport and instability south of the area as well. However, portions of northeast Iowa into southwest Wisconsin may still get in on some shower activity. The upper- level pattern looks somewhat messy for early next week, with developing eastern CONUS ridging but some energy working northward toward the area as the ridge develops. This energy is enough for the blend to give small PoPs Tuesday, but given what appears to be a weak lobe of surface ridging with drier east-northeast flow into the area, it wouldn`t be surprising if it ends up being on the drier side for most. Highs look to be in the 70s to possibly even 80s. The NBM deterministic values continue to be lower than much of its percentile guidance would suggest, with NBM 50th percentile a good 3-6 degrees warmer and suggesting widespread 80s to start the week. If things do end up dry with mixing/some sunshine, 80s appear very plausible. Increasing southerly flow will bring in mild and increasingly moist air for Wednesday into the latter half of the week, with the return of shower and thunderstorm chances as a stronger shot of shortwave energy approaches in southwest flow aloft on the back side of the eastern ridge. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1041 PM CDT Fri May 14 2021 Weak disturbance and subtle low level moisture return still triggering patchy showers overnight but ceilings remain in VFR range for most part, especially with such dry air to fight. This might gradually worsen overnight as a few more MVFR ceilings develop, but confidence not the highest given recent drier trends. Other thing to watch will be approach of stronger short wave trough in northwest flow Saturday afternoon. This could trigger some stronger convection with hints of instability and weak shear present. Details will have to be refined as threat draws closer but could see some intermittent MVFR conditions with associated thunderstorms before wave passes going into Saturday evening. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Kurz LONG TERM...Lee AVIATION...Shea
Area Forecast Discussion
National Weather Service Corpus Christi TX
624 PM CDT Fri May 14 2021 .AVIATION... VFR conditions prevail across S TX this evening. MVFR CIGs are expected to develop across S TX overnight with LRD, COT and ALI having prevailing MVFR CIGs and VCT and CRP being more intermittent. The chance for convection will increase across the western areas overnight, then spread east during the day Saturday. MVFR/IFR conditions will be possible in and near storms. The best chance for convection will be across LRD and COT. A weak southeast flow tonight will become moderate with gusts around 25kt on Saturday. && .PREV DISCUSSION... /Issued 335 PM CDT Fri May 14 2021/ SHORT TERM (Tonight through Saturday Night)... Easterly flow off the gulf is beginning to increase moisture across the area. Dewpoints along the coast have increase into the upper 60s to around 70. This moisture advection will continue and enhance through this short term period as flow shifts more around to the southeast. Rain chances this evening and tonight are fairly limited as convection expected to develop over the mountains of Mexico should take a southerly turn as it approaches the Rio Grande moving along the 850-500mb thickness lines. Some convection could clip Laredo, but chances are small...will keep only a 20 PoP. Going into Saturday, the picture isn`t super clear as models have been all over the place with expected convection. Before we get into the details, a little bit of background... A fairly vigorous upper level shortwave will push across the region from late tonight through the day on Saturday. PWAT levels remain pretty unimpressive however, topping out around 1.8 inches which is only about the 75th percentile and well below 2 standard deviations above normal. GFS in particular has backed off on QPF significantly over the past few runs. Meso models are showing scattered convection,but not widespread. In fact, the 06Z HRRR model had basically no convection over our entire forecast area for the daytime Saturday. 12Z came in looking a little better. The NAM seems to have some convective feedback or suspicious mesoscale features which has made it seemingly unreliable. That said... Have lowered PoPs a bit for Saturday period, but will still keep a high end chance at times, mainly west. CAPE is sufficient with limited CIN that thunderstorms would be expected within the convection. Chances spread east for late Saturday into Saturday night. Below normal temperatures will continue with abundant cloud cover developing late tonight and continuing through the end of the short term period. LONG TERM (Sunday through Friday)... No major changes were made from the previous forecast. A series of shortwave disturbances will push through Texas through the week in advance of a couple of deeper lows/troughs slowly moving eastward. Onshore flow will persist at the surface, increasing low-level moisture with PWATs ranging from 1.5" to 2.0" through the period. There is still quite a bit of uncertainty regarding the progression and southern extent of the energy aloft associated with the disturbances. The majority of energy aloft will be north of us and if the disturbance shifts further north, then we won`t have much upper-level support and will lack precipitation potential. Rain coverage will be sensitive to where shortwaves develop and where bands of energy aloft drape across South Texas. Yes there`s moisture in place, but there lacks surface lift while under mostly cloudy skies. It`s certainly possible that with some isentropic lift support along with the seabreeze, a few showers and thunderstorms could develop. If mid and upper-level dynamics become more favorable with divergence and vorticity in the area, we`ll see rain coverage increase. At 850mb, winds remain out of the SSE, reducing the strength of the cap to near none in the afternoon. Instability looks to be favorable for convection throughout the period, with CAPE ranging from 1500-3000+ J/kg. Overall, this forecast has a low confidence in location and amount of precipitation. Reduced rain chances on Sunday to a max of 60% near the Victoria Crossroads, latest guidances have shown a greater focus over this region; scattered showers and thunderstorms over the rest of South Texas. Only isolated showers and thunderstorms Sunday night through Monday night as a mid-level ridge between shortwave troughs runs over the area. Rain chances increase Tuesday as the mid to upper level low/trough centers over the TX Panhandle, with greatest chances of rain occurring Tuesday night through Wednesday. Another shortwave follows in wake of the main low pressure system, allowing for isolated to scattered showers and thunderstorms through the work week. High temperatures will generally range from near 85 over the Victoria Crossroads to the mid to upper 90s over the Brush Country through the period. Heat indices may exceed 105F Monday and Tuesday over the Brush Country. An increase in rain and cloud coverage could reduce these high temperatures. Lows will remain in the low to mid 70s. MARINE... A series of mid to upper level disturbances will combine with increased moisture to produce isolated to scattered showers and thunderstorms through the week. There could be a brief break in rain potential Monday night. Breezy to windy onshore flow will lead to periods of Small Craft Exercise Caution and Small Craft Advisory conditions through next week. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 72 83 73 84 75 / 10 40 40 40 20 Victoria 67 84 71 82 73 / 10 20 50 60 30 Laredo 73 89 73 95 75 / 30 50 30 20 10 Alice 70 86 72 89 75 / 20 40 40 40 10 Rockport 74 81 74 85 76 / 10 20 40 50 20 Cotulla 72 88 73 93 75 / 20 50 50 30 10 Kingsville 71 85 73 87 75 / 20 50 40 40 10 Navy Corpus 74 81 74 84 76 / 10 30 40 40 20 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ TE/81...AVIATION
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
634 PM CDT Fri May 14 2021 .AVIATION (00Z TAFs)... VFR conditions currently prevail across South Central Texas. MVFR ceilings are forecast to develop 05Z-08Z and then lower to IFR across the Hill Country, Rio Grande, and into San Antonio metro, including DRT and SAT. Ceilings are forecast to gradually rise back to VFR after 18Z. A shortwave will provide for a chance of scattered SHRAs and TSRA on Saturday. The best chances for convection will be from DRT to SAT. A tempo TSRA has been included at DRT in the morning and at SAT in the afternoon. && .PREV DISCUSSION... /ISSUED 239 PM CDT Fri May 14 2021/ SHORT TERM (Today through Saturday)... After a short break in the clouds over most of the Hill Country and areas along Interstate 35 late this morning, clouds have built back into the area. That is because increased moisture continue to arrive across the region from the Gulf of Mexico. This trend is expected tonight into Saturday morning and reflected in the overnight lows which are ranging from the mid 60s to lower 70s. These are the warmest low temperatures across most areas at least for the last 4 mornings. There is a slight chance for showers and an isolated thunder or two across the Rio Grande by day break Saturday. Both global and HiRes models suggest a mid level short wave moving across the northeast part of Mexico into the Rio Grande. Latest HRRR solution has the precipitation to the east and southeast of Del Rio on Saturday morning. Other HiRes models suggest the activity over the Eagle Pass area and to the southeast. Also, some ensemble models suggest a mid level circulation developing near Uvalde and pushing to the southeast before splitting. Okay, let us break this in three possible scenarios; could bring heavy rains for Bexar County and surrounding locations before pushing to the southeast Saturday afternoon...two...the cluster of storms could miss Bexar County for the most part with limited rainfall accumulations...three...the cluster of storms could slowly push across Bexar County and then splits sending a pulse of energy along the I-35 and produce a round of showers and storms across the Austin area late Saturday afternoon. Long story short, we could see little rain or up to one inch of rainfall with a spot or two with higher amounts mainly Saturday afternoon and evening. With saturated soils over many locations from previous rains, any additional rain in a short period of time could lead to flash flooding. Hoping to have a better picture overnight with the 00Z data for the short term period to offer more specifics to you all. Along those lines, another round of showers and storms is forecast to push across the Val Verde area on Saturday evening and push to the southeast. Some of these storms could be strong to severe and therefore, SPC Day 2 Outlook highlights most areas across the Edwards Plateau and Rio Grande under a marginal risk for severe thunderstorms. Also, WPC Excessive Rain Day 2 Outlook highlights similar area with a marginal risk of rainfall exceeding flash flash guidance. The wet pattern continues into late next week. More details below. LONG TERM (Saturday Night through Thursday)... An active period is setting up for Saturday night through much of the following week. As of now it looks like the `worst` day will be Tuesday evening into Wednesday morning with many questions in the forecast beyond Wednesday. At the start of the long term period a shortwave trough will be moving through the area as a large upper level low pressure system moves from Southern California into norther Arizona. Other than the very went 12z ECMWF, the NAM, GFS, and Canadian have shifted much of the QPF for Sunday to the east as the shortwave exits. If this trend continues current PoPs for Sunday may be overdone, especially for areas to the west of Interstate 35. Monday too is generally drier forecast wise in between the two systems. Areas to the north and east have the best chances for rain as the shortwave exits. The Canadian wants to bring a southwestward moving MCS into areas around San Angelo off of likely outflow boundaries produced by an MCS across north Texas on Sunday...but this solution is unlikely. While model soundings show modest CAPE for Monday, many models show a cap (although a weak one in place for much of Monday). The `fun` returns on Tuesday. The term `fun` is very much used loosely here as we have already had a busy spring in terms of severe weather and Tuesday looks like another busy day. The upper low will slowly move closer to Texas during the day and be close enough to provide lift across much of the area. While upper level winds look more favorable across the Panhandle and to our west over Mexico forecast soundings are very juicy across much of the area for Tuesday. Forecast soundings show 2000-3000 j/KG of CAPE and very good lapse rates. The one limiting factor may be the lack of overall shear with model soundings only showing 30 knots, as opposed to the typical 60 knots. The overall location of the upper low as it ejects into the Central Plains late Tuesday may also ultimately come into play. The GFS remains the strongest solution with a broad upper level low Tuesday into Wednesday moving across the Texas Panhandle. The ECMWF and Canadian have the upper low further north, across Colorado and Kansas. If this solution verifies the better severe chances may be more to the north on Tuesday. SPC mentioned the threat in their day 4-8 outlook, but wanted to see run-to-run consistency in the models before drawing an outlook area. The other big concern will be the heavy rainfall threat. We have seen several events already this spring with very heavy rainfall rates. This event looks now different. Precipitable water values from model soundings and the GFS ensemble all show 1.5 to 1.6 PW values which are close to or exceeding the seasonal max values. Interestingly the Ensemble Awareness Tables which show the standard deviations of the model PW values is not pegging Tuesday yet, but rather showing this weekend and late in the week as days of higher concern. Regardless GEFS ensembles are centering around 2-4 inches of rainfall, with 12z model averages of 3-4 inches through Wednesday. Some higher totals up to 5 inches are certainly possible, especially when you tack on Thursday and Friday. Speaking of Thursday and Friday models differ on how they handle the shortwave that follows the big upper low. What is certain is that the rainy pattern will continue. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 66 82 68 81 71 / 0 30 40 60 30 Austin Bergstrom Intl Airport 65 82 68 81 71 / 0 30 40 60 30 New Braunfels Muni Airport 66 83 69 83 72 / 0 40 40 60 30 Burnet Muni Airport 65 80 67 80 69 / 0 30 50 60 30 Del Rio Intl Airport 70 85 70 89 73 / 10 50 50 30 10 Georgetown Muni Airport 64 82 67 81 70 / 0 20 40 70 30 Hondo Muni Airport 67 82 68 85 72 / 10 60 50 40 20 San Marcos Muni Airport 65 82 68 82 71 / 0 30 40 60 30 La Grange - Fayette Regional 65 85 70 83 73 / 0 10 30 70 30 San Antonio Intl Airport 68 82 68 83 71 / - 50 50 50 30 Stinson Muni Airport 69 83 70 84 72 / - 50 50 50 20 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term/Aviation...Runyen Long-Term...Oaks Decision Support...33
Area Forecast Discussion
National Weather Service Grand Forks ND
1001 PM CDT Fri May 14 2021 .UPDATE... Issued at 1000 PM CDT Fri May 14 2021 From satellite, 500 mb system near Bemidji. Pocket of lower clouds near this rotating around Bemidji/Waskish area. Remaining showers just west of Grand Forks weakening as are the leftover showers in far NW MN. Atmosphere not condusive for continued showers overnight so will continue to see slow weakening. UPDATE Issued at 713 PM CDT Fri May 14 2021 Showers and thunderstorms are diminishing after peaking in intensity between 430 and 630 pm. Slow diminishing trend this evening will continue. 500 mb short wave moving very slowly and is near the SD/MN/ND border and this area did have more instability and a bit more coveage of storms and storms with mainly small hail. Shower/t-storm chances will diminish thru midnight. Cloud cover Bemidji to Park Rapids area prevented as much heating and that area has seen little in the way of rainfall today and this trend should continue. Will update pops a bit for current and forecast thoughts. && .SHORT TERM...(This evening through Saturday night) Issued at 339 PM CDT Fri May 14 2021 Isolated severe thunderstorm potential this afternoon/early evening over the far southern RRV into west central MN, with primary threats 1" hail and winds to 50 mph. There is also a very low potential for funnels or even a non supercell tornado near the SD state line this afternoon (very low confidence in occurrence/impacts). 700 MB close low and associated mid level vorticity advection is moving over our CWA, and with peak heating/steep low level lapse rates clusters of showers/weak thunderstorms have developed. RAP objective analysis indicates MU CAPE values with elevated parcels near 1000 J/KG in our far south, with effect shear values under 20kt. Freezing levels between 6500-8000 FT AGL is low enough that it shouldn`t take a particularly tall updraft to produce at least small hail if not a few isolated reports of 1" hail before sunset. DCAPE is minimal (around 500 J/KG), so while severe wind isn`t anticipated there is still potential with inverted-V type soundings for wind gusts 40-50 mph with taller cores. Storm motions are tending to be very slow with variable motions due to low shear and mid level center overhead. Mid level lapse rates/cold pool aren`t particularly impressive, but with this rotation in place and surface vorticity increasing in our south there is a very low potential for a few funnels. Non supercell tornado parameter is positive near the SD where 0-3km CAPE and surface vorticity are maximized and "if" there was a funnel in this environment there may be enough stretching for brief tornado development. This is highly conditional/uncertain and not an ideal set up. Still, worth monitoring thorugh the peak heating period of the afternoon (next few hours). We should see a rapid decrease in intensity and eventually coverage with the loss of daytime heating. Eventually the the shortwave moves east and any lingering showers in our east should taper off. There are a few subtle mid level impulses Sunday near the International Border that may spark a few afternoon showers (very light) otherwise drier conditions are expected again. Warm temperatures continue and with less cloud cover potential is there for most locations to reach the 70s if not close in on 80 within the RRV (near 70 favored in the east). This may also result in lower RH values in the 20-30 percent range, but with lower wind (gusts generally around 15 mph) near critical fire weather is currently not anticipated (will monitor). .LONG TERM...(Sunday through Friday) Issued at 339 PM CDT Fri May 14 2021 Warmer temperatures and rain chances dominate the forecast for next week. After this weekend`s rain chances, the upper levels shift into a ridging pattern. This will be conducive to warming temperatures getting into the 80s and quiet weather for the first half of the work week. Once we reach mid-week, rain chances return to the region. Showers and thunderstorms will be possible for the remainder of the forecast period as a low pressure system develops to our west and then moves into Canada. Precipitation amounts appear to be minimal in the ensembles. Guidance is not conclusive on timing, path, and amounts but will start to get a better handle on the event as we get closer in time. Rain will not do any good for our temperatures though, as highs are expected to remain in the upper 70s and low 80s. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 713 PM CDT Fri May 14 2021 Bemidji area in a region of MVFR clouds and tendency for these to hold steady thru the night. Otherwise VFR thru the pd with scattered cloud layers, CU field in the 6000 ft agl range with some mid and high level moisture above. Winds this evening south- southeast RRV and east and more northeast to north west of the RRV as weak surface low moves through. Trend will be for all winds to diminish to 5 kts or less overnight and be variable even into Saturday daytime. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. $$ UPDATE...Riddle SHORT TERM...DJR LONG TERM...AK AVIATION...Riddle
National Weather Service Sioux Falls SD
1035 PM CDT Fri May 14 2021 .SHORT TERM...(This Evening through Saturday) Issued at 245 PM CDT Fri May 14 2021 Focus for the remainder of the daytime hours will be on a weak surface trough/wind shift currently located across central SD. Mid afternoon RAP mesoanalysis suggests a ribbon of 100-300 J/kg of MLCAPE and perhaps up to 1000 J/kg of SBCAPE near and ahead of this convergence zone with a bubbling Cu and weak radar returns from NE SD to Huron to Winner. Earlier outlooks from SPC had highlighted areas just west of I-29 in a Marginal risk for severe weather although with effective shear running around 35 kts or less (and high cloud bases), organized severe weather seems unlikely and that risk area was removed in the mid-day issuance. With that said, in the presence of a relatively low freezing level and marginal instability, can`t completely discount the idea of a stronger storm or two producing hail approaching severe criteria. Additionally, winds through the lowest 10-15 kft are fairly light so not much to mix down, however inverted-V-type soundings may allow for an occasional gust up to 40 mph with any stronger activity. This all should be largely diurnally driven and thus suspect after sunset a rapid decrease in any activity that may exist. Overnight period may bring some fog to the region with a moistened boundary layer and light winds. High-res guidance has varying degrees of this potential with SREF probabilities highest east of I- 29. Could see some mid-upper level clouds overhead as well which would likely temper this fog potential. Have added in some patchy mention for now and will monitor trends going forward. We should be able to shake any morning cloud cover/fog by mid to late morning with a fair amount of sunshine by Saturday afternoon. With some weak uncapped surface based instability, may also see additional Cu bubble up. A handful of the high-res guidance tries to generate some weak convection under these conditions and thus have introduce some slight chance POPs. With some upper level subsidence by mid to late afternoon, this seems like a low probability scenario however. Otherwise, widespread temperatures in the 70s expected. .LONG TERM...(Saturday Night through Friday) Issued at 245 PM CDT Fri May 14 2021 A compact wave may allow for a blossoming area of showers and thunderstorms off of the Black Hills by Saturday night that will drift eastward into Sunday morning. However with the better instability shunted well south, these will likely have a fading tendency as they approach our area. Additionally, this wave generally shears/weakens through the day Sunday and while can`t discount some low end chance level POPs for Sunday, the better chances appear to be from the MO River Valley and points south. Temperatures again a few degrees either side of 70 although any lingering precipitation may contaminate temperatures as well. Northern stream jet pushed into Canada for early next week with broad ridging as a cutoff low fills across the Desert Southwest. Some indication that a fractured southwest flow regime sets up by Tuesday into next week that may lift various disturbances into our area but with an interrupted moisture and instability plume wouldn`t expect anything in terms of any significant convection. Timing in the arrival of these shortwaves is also inconsistent from model to model and run to run leading to a smeared period of POPs that are likely too robust temporally. In other words, would characterize this period as potentially active in terms of precipitation but far from a washout. Temperatures will again be dependent on precipitation timing/coverage but 70s seem like a good starting point for highs. Perhaps some better signal for west coast upper level troughing by late in the week which should help to usher higher moisture content air into our region which is also denoted by PWATs finally sneaking into the upper quartile of climatology. This may also provide some modest increase in our severe weather chances which is also reflected in CIPS analogs. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1030 PM CDT Fri May 14 2021 Scattered convection will continue across portions of southwest Minnesota into the early overnight hours as a subtle wave moves through. Elsewhere, VFR conditions continue into the overnight hours. Fog probabilities have fallen slightly due to the increased cloud cover, and have backed off slightly in current TAFs. Winds will remain light on Saturday, with the quick development of a CU field by mid-day and through the afternoon. Should convective temps in the 70s be met, then a few pop-up storms could be possible. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...Kalin LONG TERM...Kalin AVIATION...Dux
Area Forecast Discussion
National Weather Service Goodland KS
925 PM MDT Fri May 14 2021 .UPDATE... Issued at 924 PM MDT Fri May 14 2021 The severe thunderstorms watch for the area has been cancelled. The area of severe storms has moved out of the area and no additional severe storms are expected to move into the area during the remainder of tonight. && .SHORT TERM...(This evening through Saturday night) Issued at 243 PM MDT Fri May 14 2021 Satellite and 500 mb RAP analysis showed northwest flow over the region early this afternoon, with a shortwave moving into Colorado. Weak ridging was observed from the Four Corners region up towards the Great Basin. Mid to high level clouds developed off the Rockies as the shortwave approached, gradually pushing into the region while storms form along the Front Range. At 2 PM MT, northeast winds were observed at 10 to 15 mph with temperatures in the upper 60s to low 70s. A few thunderstorms are expected to move into eastern Colorado during the mid to late afternoon hours. Storms are expected to increase in coverage (likely becoming a cluster or two) as they progress east into northwest Kansas and extreme southwest Nebraska during the evening hours and the shortwave kicks through the area. Shear near 40 knots (increasing to near 60 knots in the evening), CAPE of 1000 to 2000 J/kg, and steep lapse rates will support severe thunderstorms this afternoon and evening. The main hazards initially appear to be large hail and damaging winds. Although a tornado cannot be ruled out, dry air at the surface and high LCLs will really limit tornado development for this event. As storms transition to a complex tonight, concern turns more towards a damaging wind and heavy rainfall threat. PWATs nearing 1 inch (with 1.25" not out of the question for eastern portions of the area), suggest that locally heavy rainfall will need to be monitored. Thunderstorm activity slowly exits the region to the east/southeast overnight into early Saturday as temperatures fall into the mid 40s to mid 50s. Another point to quickly mention...There appears to be a signal for fog returning to the region late tonight into early Saturday, although it looks more widespread than previous nights. The fog and stratus are forecast to set in after midnight. Reduced visibilities could cause hazardous travel for the morning commute. However, locations that will be most impacted is uncertain at this time. For Saturday, some guidance shows showers and storms lingering along the Nebraska border and eastern part of the area into the morning hours. There should be a lull midday before another round of thunderstorms develops in the afternoon. The setup will be similar to today. Looks like a few storms will initiate along a surface trough in eastern/central Colorado during the afternoon before pushing east and forming a cluster once again. While shear appears to be lower, steep lapse rates and good instability indicate that large hail and damaging winds are potential hazards. Otherwise, expect highs in the upper 60s to low 70s tomorrow, and lows in the 50s Saturday night. .LONG TERM...(Sunday through Friday) Issued at 155 PM MDT Fri May 14 2021 The long term period is looking unsettled with near constant chances for rain through the week. Temperatures look to be near average with highs around 70. Sunday starts with slight ridging aloft at 500mb that will transition to more of a laminar flow out in front of an advancing cut-off low. The cut-off low will then slowly move towards and into the area during the early week before diffusing out into the larger flow. The end of the week looks to have the ridge set up over the Eastern CONUS while a trough moves into the Western CONUS. This pattern may provide some slight synoptic support for storms but looks to be relatively weak in flow and potentially even split the flow. Near the surface, the Tri-State area appears to be between two larger areas of high and low pressure with higher pressure to the east under the upper ridge and lower pressure to the south and west as the cut-off low moves closer to the area. With lower pressure to the south, moisture is forecasted to be pulled from the Gulf of Mexico north into the area. The question becomes how much of this moisture will be realized and actually pulled into the area. Guidance has been shifting the lower pressure further south in more recent runs and the precip appears to be shifting south with it. Also making things more interesting is a nearby cold front that passes through Sunday and cools temperatures slightly going forward. What all of this means is that the current forecast calls for rain and storms for most of the week with the greater rain chances and amounts currently arriving on Sunday after the front. The rest of the week may have similarly high chances, but confidence in coverage and higher rain amounts is low due to the general shifting of the lower pressure south. Without the support for lift and if cloud cover from the system in the area limits daytime heating, storms will likely be lesser in coverage and intensity. Temperatures are expected to be relatively steady until the end of the week with highs forecasted in the 60`s and 70`s. There could be some variations due to cloud cover or lack there of in certain locales but this will be clearer as each day gets closer. While severe threat currently looks to be low for much of the week, there could still be a chance if clouds break for daytime heating. There also could be a chance next weekend as a similar setup to recent days is appearing in guidance with a Front Range low and southerly flow bringing moisture north. Still plenty of uncertainty with that solution. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 510 PM MDT Fri May 14 2021 GLD will remain VFR as thunderstorms move through the vicinity between 01-06Z this evening. Expect -TSRA to be a prevailing conditions between 03-04Z with intermittent moderate to heavy rain along with gusts to 45kts as storms are expected to pass over the TAF site. After storms pass, conditions are expected to transition to IFR between 10-15Z due to low ceilings and areas of fog that will bring visibility down to around 2 miles. Fog is expected to dissipate with lifting ceilings by 15Z with a transition up to MVFR conditions followed by VFR conditions after 20Z. MCK will have VFR conditions with thunderstorms moving through the vicinity between 03-08Z. A short period of more storms moving across the site is expected between 03-04Z with moderate to heavy rain and wind gusts to 40kts. Between 08-14Z, conditions are expected to drop to IFR due to lowering ceilings and areas of fog that will bring visibility down to around 2 miles. Conditions improve to MVFR after 14Z as fog dissipates and ceilings raise, and VFR after 19Z and ceilings continue to raise. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...LOCKHART SHORT TERM...JBH LONG TERM...KAK AVIATION...LOCKHART
Area Forecast Discussion
National Weather Service Gray ME
1029 PM EDT Fri May 14 2021 .SYNOPSIS... After a cool and calm night tonight, warm weather continues over the weekend into early next week, although healthy sea breezes will develop during the afternoons and keep conditions cooler near the coast. We will be in a pattern over the weekend into next week where abundant morning sunshine will lead to enough instability to bring chances for afternoon showers and a few thunderstorms each day. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Update... Isolated showers will continue to diminish across the forecast area per latest radar imagery as of 0238Z. Just about all of the precipitation is not reaching the ground late this evening as surface dew points remain very low this evening. The latest HRRR has this precipitation diminishing as well over the next hour. Temperatures will be monitored closely this evening as there will be rapid drops in readings overnight as winds decouple under clearing skies. Frost at this time should be limited however over central sections and mainly confined to northern zones which have yet to set the frost/freeze program. Prev Disc... After a warm day today, with spotty showers providing brief wind gusts to 20-30 mph, winds will calm and temperatures will cool into the upper-30s to mid-40s tonight. While low dewpoints today, in the upper-20s to mid-30s at this hour, leave plenty of room to drop tonight, I do anticipate lingering cloud cover and a few-millibar surface PGF to prevent temperatures from cratering too much tonight. At any rate went with the coolest guidance, but no lower. Will have to watch trends in guidance in case a frost advisory becomes necessary, at this juncture most likely for the Connecticut River Valley. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Tomorrow will be awfully reminiscent of summertime for the region. Temperatures are expected to warm quickly into the 70s late in the morning, perhaps flirting with 80 over interior southern New Hampshire. High pressure however will be overhead with a weak PGF... which will open the door for a healthy sea breeze to form early, slowing the warming trend along the coast. Regardless, the warmth and initially mostly sunny skies, coinciding with the fact that it`s Saturday, will likely encourage many to flock to the mountains, lakes, and beaches. Since inland lake and oceanic temperatures remain in the upper-40s to low-50s, a Beach Hazard Statement was coordinated with the USCG along the New Hampshire Seacoast and the southern and Mid-coast of Maine. An information statement for inland cold water will be issued later this evening. Besides those sensible weather impacts, am also expecting another day of diurnally driven shower and thunderstorm activity. Showers start to pop mid- to late-morning along a zone of convergence over western Maine, then grow in coverage through the day, coming to an end late in the evening. An upper level wave over Quebec will provide some upper level support, and also steepen lapse rates a bit aloft, which will allow for greater coverage in and north of the mountains into central Maine. These will again be capable of producing gusty winds with dry low- levels offering a few hundred J/kg of DCAPE... although tall- skinny CAPE and weak shear don`t offer much in the way of updraft strength or duration. Dry air remaining over the Connecticut River Valley into extreme southwest Maine will make it tougher for these showers to form, let along reach the ground. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Overview...The first half of the long term looks decidedly more active than the first half as a weak frontal boundary lingers near or over the region. A frontal passage on Tuesday should bring an end to the daily chances for showers and thunderstorms Sunday through Tuesday. Some of the stronger storms on Sunday (and possibly on Monday and Tuesday as well) could produce gusty winds and small hail. Temperatures look set to warm up well above normal through mid- week before potentially coming back closer to normal toward the second half of the week. Impacts...Stronger storms on Sunday could produce gusty winds and small hail. These hazards will again be possible in any stronger storms on Monday and Tuesday. Forecast Details...Looking at the first half of the long term, expecting the bulk of any precipitation over the period to fall over these three days. All of this will occur from showers and thunderstorms, so not expecting widespread significant amounts with some locations receiving more then others...typical of diurnal convection. Sunday remains the most favorable day for both coverage of showers and thunderstorms and potential for stronger storms to produce gusty winds and small hail. Isolated thunder looks possible all the way down to the coast, though any inland progression of the sea breeze may ultimately hinder any storms that manage to make it there. The best chance for thunder will be in northern and western areas...and these areas are the best best to see any gusty winds or small hail from any storms. All activity should diminish pretty quickly with the loss of daytime heating. Monday looks similar to Sunday, but with less upper level support from building ridging aloft, not expecting quite as much coverage or intensity compared to Sunday. Northern areas again stand the best chance to see thunder and potentially gusty winds or small hail. Tuesday sees the passage of a cold front with yet another chance for showers. Do think that there could be a few thunderstorms as well, mainly along the international border. After the frontal passage, the remainder of the period looks rather dry with perhaps some afternoons showers possible on Wednesday and Thursday. Temperatures will be on a gradual warming trend into mid-week with the warmest temperatures of the season possible on Wednesday and Thursday. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Short Term...VFR for all terminals through tonight with gusty west to northwest winds today going light and variable to calm tonight. A general westerly wind after sunrise tomorrow will relent to onshore flow for coastal terminals by mid-morning, reaching interior locations like AUG/MHT/CON by mid-day. Brief restrictions are possible in -SHRA/isolated TSRA during the afternoon and evening hours with greatest likelihood of this occurring at KAUG and KHIE... least likely for southern terminals. Long Term...VFR conditions expected at all terminals, outside of any brief restrictions from showers or thunderstorms. With high pressure dominating, winds will generally be light. && .MARINE... Short Term...High pressure gradually moves out over the waters through tonight and into tomorrow, which will keep seas and winds suppressed below SCA thresholds. Otherwise afternoon and early evening showers forming over land may track over the coastal waters before dissipating today and tomorrow with a low, but non-zero, change for a thunderstorm. Long Term...Winds and seas expected to remain below small craft criteria through the period. There is a chance that a few isolated showers, and possibly a thunderstorm or two, affect the waters Sunday and Monday afternoons. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Beach Hazards Statement from 8 AM EDT Saturday through Saturday evening for MEZ023>028. NH...Beach Hazards Statement from 8 AM EDT Saturday through Saturday evening for NHZ014. MARINE...None. && $$ NEAR/SHORT TERM...Cannon
Area Forecast Discussion
National Weather Service Wichita KS
656 PM CDT Fri May 14 2021 .SHORT TERM...(This evening through Sunday night) Issued at 317 PM CDT Fri May 14 2021 Currently have northwest flow aloft over the Plains with weak upper troughing over southern CA. At the surface, high is situated over the Ohio Valley with return flow ramping up across the Southern Plains. There looks to be a weak warm front stretching from NW KS into far southern Nebraska. Elevated storms lingered this morning over south central KS with additional development early this afternoon near Wichita. This activity is making it`s way off to the southeast with the stronger storms producing small hail. This activity has been driven by persistent theta-e advection in the 700-600mb layer and should continue to push east late this afternoon and weaken as it runs into less instability. Storm are then expected to develop out over western KS/eastern CO early this evening due to increasing low level moisture over this area along with some upslope enhancement. Weak warm front will also remain situated over northwest KS which could help increase convergence necessary for initiation. Anything that develops out west will track east/southeast tonight. In addition, 850-700mb moisture transport looks to ramp back up after dark and will either help storms hold together as they track east or allow for additional development. 1000-1500J/KG of elevated CAPE and 25-30kts of effective shear should allow for some low end severe criteria for the stronger storms tonight. Right now it appears this activity would reach the Wichita area generally after 1 am. Very difficult convective forecast setting up for Sat, as much of it will depend how widespread storms are tonight and how far south the weak cold front ends up being pushed. Right now going with the thinking that overnight elevated activity will be moving into eastern KS by the late morning hours with a lull in activity Sat afternoon. Then expecting the potential for storms to develop along the front near the KS/OK border late Sat afternoon or early Sat evening. While feel the better chances for surface based storm initiation Sat will be further west over the high Plains, can`t rule out a few storms over far southern KS due to lack of capping and plenty of instability. Even with less than ideal shear for severe storms, still feel there will be enough instability for any storm that develops to become severe. There looks to be some model agreement on slowly lifting an upper impulse out of the southern High Plains Sat evening and across central/eastern OK during the day Sun. This will keep showers and storms in the forecast for Sun morning with the better chances moving into eastern KS by Sun afternoon/evening. .LONG TERM...(Monday through Friday) Issued at 317 PM CDT Fri May 14 2021 By Mon morning, upper impulse will be lifting into MO with a closed upper low slowly migrating across the Desert Southwest. So we may see a lull in activity for Mon as our forecast area will be in-between the two low pressure systems. Southwest CONUS upper low will start to directly impact the forecast area late Mon night with the highest precip chances looking like Tue night into Wed as we get into an area of decent upper diffluence. While confidence is high we are not looking at a widespread severe weather episode, it`s tough to completely rule out a strong or severe storm given the time of year. Should see another overall decrease in storm potential for Thu afternoon into Fri as the shortwave lifts off into the Upper Mississippi Valley. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 653 PM CDT Fri May 14 2021 Challenging aviation forecast with location/timing of storms and potential for MVFR or IFR ceilings late tonight and Saturday morning. Best estimate based on recent high resolution models and verification of said models last night, suggest a line or cluster of storms will traverse the KGBD-KHUT-KCNU axis late this evening and overnight fairly quickly. Uncertainty will result in at least a mention of storms at all sites during the night. Beyond that confidence dwindles. Much of the ceiling issues revolves on boundary layer moisture forecasts, of which HRRR is one of the driest and many are quite moist. Suspect the higher relative humidity is a function of model bias to over saturate boundary layer in upslope flow. Given skepticism opted only to go MVFR for now. Also some potential for showers to develop along and north of outflow boundary or along elevated front late tonight and into the morning, but lack of confidence resulted in VCSH at most. -Howerton && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 58 72 61 72 / 70 50 70 70 Hutchinson 57 72 59 72 / 80 40 60 70 Newton 57 70 60 72 / 80 50 70 70 ElDorado 57 70 60 72 / 80 60 70 80 Winfield-KWLD 58 74 62 72 / 50 60 70 80 Russell 56 72 56 72 / 80 30 50 70 Great Bend 56 73 57 72 / 80 30 60 70 Salina 56 72 58 72 / 80 40 60 70 McPherson 56 71 59 72 / 90 40 60 70 Coffeyville 56 73 61 73 / 70 70 80 70 Chanute 56 68 61 72 / 90 80 70 80 Iola 55 67 60 72 / 90 80 60 80 Parsons-KPPF 56 71 61 72 / 80 70 70 70 && .ICT WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...RBL LONG TERM...RBL AVIATION...PJH
Area Forecast Discussion
National Weather Service Marquette MI
634 PM EDT Fri May 14 2021 .SHORT TERM...(This evening through Saturday) Issued at 327 PM EDT FRI MAY 14 2021 Latest WV imagery and RAP analysis reveals a shortwave moving across the Upper Great Lakes with maybe another couple of shortwaves upstream over the Dakotas and eastern MT. Increased mid-level moisture and weak forcing from the shortwave moving over the area combined with merging lake breeze boundaries have resulted in the formation of isolated showers over mainly the east half of the U.P. this afternoon. There were even a couple of lightning strikes over portions of southern Schoolcraft County. Generally expect these isolated showers to continue over the east half of the U.P. into early evening as MLCAPEs remain in the 100-200 j/kg range. Deep mixing over the interior west half has resulted in dewpoints in the low 20s with min RH values lowering to around 20 pct. Light winds however will ease fire wx concerns. Highs across the area have generally been in the 60s, although a few spots have topped the 70F mark. Tonight, any showers and most of the clouds will diminish during the evening. Expect enough radiational cooling overnight to drop min temps to around 40 inland and to the mid and upper 40s along Lake Superior where weak downslope southerly flow prevails. Shower chances associated with an approaching the west ahead of an approaching shrtwv and sfc trough should hold off until Saturday. Saturday, next shortwave approaches from the western/northern Plains. Weak isentropic ascent and theta-e advection ahead of the shortwave should result in scattered light showers, especially west half and south central portions in the afternoon. Expect highs to range from the lower to mid 60s west half under more clouds to the upper 60s east where there should be a bit more sun. More sunshine east should result in deeper mixing, lowering min RH values into the 20 to 25 range. The dry conditions combined with a bit stronger, and perhaps gustier, southerly gradient winds could result in borderline elevated fire weather concerns over the eastern counties on Saturday. .LONG TERM...(Saturday night through Friday) Issued at 534 PM EDT FRI MAY 14 2021 The medium to extended forecast will trend toward normal to above- normal temperatures, and near normal precipitation chances for the next two weeks. Zonal to upper level ridging will be present over the Great Lakes overall, with multiple shortwave disturbances riding along the flow to create the opportunity for occasional showers at times, but not amounting to much for precipitation. Saturday night through Sunday night will trend towards a couple of shortwave disturbances riding along the 500mb upper level zonal flow. The zonal flow will trend toward weak ridging, thus allowing temperatures to remain warm on Sunday. PWATs look rather low for the moisture source on Sunday afternoon/evening as the shortwave propagates aloft with 0.5-0.75". A few vorticity maxes may propagate through the area enhancing the dynamics for any showers that develop over Upper Michigan, but wind shear isn`t there to assist with stronger convection development at this likely to be more of the same as Saturday with showers. Upper level ridge will begin to intensify on Monday over the Great Lakes, limiting chances of diurnal shower activity from occurring, albeit warmer temperatures can be expected to start the week. An upper level low will become closed off from the main jet energy on Sunday/Monday over the 4 corners region of the CONUS, so there will be temporary split flow aloft between the northern and southern streams of jet energy. As this upper level low slowly propagates over the 4 corners to the southern Rolling Plains from Monday into Tuesday, it will begin to be absorbed back into the main jet energy. This will allow for a shortwave trough to become negatively tilted over the Central CONUS. At the same time of the shortwave trough deepening, the potential increases for a weak omega block feature to develop as an upper level ridge will become elongated from the southeast further upstream toward the Great Lakes/Canadian Provinces. Model guidance begins to differ by Wednesday, with different signals of where the placement of possible convection over the Upper Mississippi Valley and Great Lakes may occur. Trends continue with warm temperatures from Monday into next weekend where chances of afternoon convection and above average temperatures are possible for the latter portion of the week. Long range guidance of 850mb temperatures over Upper Michigan on Thursday through Saturday are upwards of 18C-20C. This would easily put diurnal maximums at the 80+ degree threshold for several areas across Upper Michigan. We will continue to monitor the long range guidance in the event that signals for more organized convection with the weather system next week look marginal or better. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 633 PM EDT FRI MAY 14 2021 VFR conditions will continue at CMX and SAW through the forecast period. IWD will be VFR into Sat morning before MVFR cigs come in with a small chance for showers Sat afternoon. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 327 PM EDT FRI MAY 14 2021 High pressure will remain over the Great Lakes for the next several days, limiting wind gusts over the lake to 15 knots or less into much of next week. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Voss LONG TERM...BW AVIATION...07 MARINE...Voss