Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/13/21

Area Forecast Discussion
National Weather Service Amarillo TX
629 PM CDT Sat Jun 12 2021 .AVIATION... There is still some uncertainty about the potential for some thunderstorms to make it into the Oklahoma and Texas Panhandle from New Mexico. Main timing will be from about 02Z for KDHT, 04Z for KGUY, and 06Z for KAMA if they are to be impacted. Have VCTS in the TAF as confidence is still not very high if these storms will maintain themselves or how wide spread they will be. If thunderstorms do make it into the area this could create concern for LLWS even if they are up to 5 miles away. Surface winds will be out of the east to south around 5 to 15 kts, without interference from outflows. CIGs should also remain above 9k ft outside of any active thunderstorm. Hoffeditz && .PREV DISCUSSION... /Issued 349 PM CDT Sat Jun 12 2021/ SHORT TERM...Tonight through Sunday Night... H5 ridge axis extends from NRN Mexico into W Texas. Two subtle ridge riding S/WVs can be seen in WV imagery in NRN NM and ERN AZ and these are forecast to cross the region through the overnight hours. The low level flow has returned to a more easterly direction behind yesterdays front which is now located near a Hereford Wichita Falls line, but will slowly lift and become more diffuse through the night allowing winds to turn more SE. Abundant low level moisture remains near and north of the boundary and Tds are in the 60s with even some low 70s. Models agree that H7 moisture advection has been occurring through the day with an H7 theta-e ridge setting up near the WRN Panhandles. MLCAPE is around 2500-3500 J/KG and the SPC RAP shows an impressive 3000-4000 MLCAPE by 01 UTC. While this seems high, it should be noted that the 12Z sounding showed observed MLCAPE of just over 4000 J/KG which might be a record for the station! Effective bulk shear is forecast to the be 30-35 tonight while the 0-3km helicity increases to 200-300 with the help of a 30 kt LLJ. This all seems to be setting the stage for a TSTM event and assoc severe chcs with discrete cells possible early in the evening possibly congealing into an MCS, HOWEVER there is one major caveat - there is a cap. While all the momentum was towards the more agressive models 18-24 hours ago, that has come to a screeching halt since then and models have reverted to extremely different solutions regarding how tonight will play out. Although the GFS remains extremely agressive (and persistent), am somewhat dubious of this solution given what appears to be convective feedback that significantly strengthens the S/WV over the WRN Panhandles before it crosses to the east. The FV3 Hi-res is one of the more agressive CAMs (GFS influence?) and SPC HREF is relatively excited as well with developing an MCS, but HRRR, NAM and others are not (HRRR not at all). SPC has expanded the SLT risk through the day and it now includes the entire WRN Panhandles (including a hatched area for wind west), but there is still significant uncertainty given huge spread in model guidance that ranges from an MCS impacting much of the area to nothing holding together vs the cap and very little or nothing happening. Current forecast is closest to the TTU WRF which is a nice compromise solution. Forecsat is showing SCT TSTMs in the west this evening (40-50% coverage) and lesser coverage in the east as things weaken (20-30%). There would be a threat for large hail and damaging wind and and a very low tornado potential in this case. If the most aggressive CAMs verify, a significant MCS would provide even higher wind and heavy rainfall threat which is why SPC is also highlighting a significant wind threat (hatched area) in the SWODY1. H5 ridge builds north towards the Four Corners with mid level flow becoming more NNW on Sunday. This flow regime does not favor NM mountain convection crossing the border, but CAPE remains very high and wind shear is sufficient that we can not rule out influence from mountain generated storms further north than normal. S/WVs riding this ridge also could cause cap to break allowing isolated storms to form locally. Without presence of a boundary to provide low level forcing, POPs have been limited to SLT CHC tomorrow and tomorrow night but are above the NBM forecast POPs which are less than 15 across the board. Even though we are not seeing heat advisory level temps or heat index, we have received word regarding heat related issues occurring in the Canyon (heat index near 102 there). These dewpoints are extremely high for the area and it is apparent, we are not used to it. Gittinger LONG TERM (Monday through Friday)... Overall, pretty quiet forecast in the extended. Seasonable temperatures are forecast with mostly dry conditions. Friday is our next best shot at seeing rainfall. High temperatures will be mostly in the 90s next week with a few locations flirting around 100 degrees. On Monday, the H5 high will be centered over the Four Corners region, and will sit over in this general area for several days before eventually flattening out by the end of the work week. This will result in a northwest flow pattern aloft. This pattern is pretty typical for summer time convection here in the Panhandles, and there will be a chance for thunderstorms to come off the higher terrain to the west. There is also a chance for a cold front to makes its way into the region, but models differ a lot on the southward progression. The GFS is pretty aggressive bringing it all the way into the Panhandles. If this comes to fruition, we will have small perturbations within the northwest flow which may interact with the cold front. This could result in widespread rainfall. However, the GFS seems to be the outlier here with several other models holding the front up in Kansas. We will have to watch how this trends going forward. Otherwise, the long term is pretty quiet with lots of sunshine and relatively light winds speeds. Guerrero && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$ 36/11
Area Forecast Discussion
National Weather Service Cleveland OH
1001 PM EDT Sat Jun 12 2021 .SYNOPSIS... Weak low pressure and an associated cold front will slowly move east across the area tonight through Sunday. High pressure will briefly build across the region Sunday night before another low and a cold front moves southeast across the region Monday. && .NEAR TERM /THROUGH SUNDAY NIGHT/... 1000 pm update... No significant changes were needed to the ongoing near term forecast this evening and overnight. Previous Discussion... The cumulus field south of the lake breeze remained benign through the afternoon. Regional radars showed isolated thunderstorm complex over northern Indiana and just northwest of Detroit. HRRR show more convection moving across Michigan and northern Ohio after midnight. Afternoon package captures this feature with some weakening after midnight. The activity over northern Indiana is worth watching. As this activity and upstream cold front progresses east overnight, activity should continue to weaken and become more isolated/scattered, with slight chance pops progressing eastward across the area overnight. Previous Discussion... The cold front will push through the area on Sunday. Destabilization ahead of the front will support another round of showers/storms developing by the afternoon hours, and the impact on the local area will be contingent on the speed of the front. Model consensus shows the bulk of any destabilization and associated convection occurring just east or on the eastern periphery of the forecast area tomorrow afternoon. Upwards of 2000 j/kg SBCAPE may build into the far eastern part of the area before the front moves through, but currently thinking the bulk of the severe threat and convective activity will be just east of the area. High pressure will briefly build across the area late Sunday through Sunday night, although rain chances may sneak back into the northwest part of the area late Sunday night as a stronger wave quickly pushes southeast through the Great Lakes. Highs on Sunday will again be in the low to mid 80s across the area. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... An upper-level trough will deepen as it moves east across the Great Lakes Monday and Tuesday and a steep ridge begins to build east into the Plains. Lingering moisture will provide sufficient instability for shower and thunderstorm development across the area late Monday morning through early Monday evening and any precip chances should quickly diminish Monday night as dry air begins to build east over the area. Temps will be in the 70s across NW PA/NE OH and the upper 70s to low 80s across NW OH. Although drier air will manage to seep in from the west by Tuesday, there may be just enough moisture and instability to support a slight chance of isolated diurnal showers and thunderstorms during peak heating Tuesday afternoon. Otherwise, Tuesday will be quiet with highs in the 70s to near 80 degrees in the northwestern reaches of the CWA. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... The start of the long term period will be characterized by dry weather as weak cold air advection develops over the area on Wednesday. Temperatures in the 70s with dew points in the 40s will provide some relief from the recent heat and humidity through Thursday, although temps may creep into the 80s in NW OH Thursday as a ridge builds over the area from the southwest. Temps will briefly increase Friday, with highs climbing back into the 80s. The next significant chance of rain will arrive as a shortwave moves across the area Friday and a cold front may skirt across the area Saturday. Depending on the timing of the cold front, temperatures may fall back into the 70s on Saturday. && .AVIATION /00Z Sunday THROUGH Thursday/... VFR conditions are expected through most of the forecast period. There is an outside chance of SHRA/TSRA after 00Z due to approaching convection over northern Indiana. Otherwise, conditions will be dry through the period. Some MVFR to potentially IFR cigs/vsby may develop at KCAK, KYNG, and KERI after 06Z tonight before weak cold front cross the area near the end of the period. Light/variable winds are expected overnight becoming northwesterly on Sunday. Outlook...Non-VFR possible in thunderstorms Sunday morning into mid afternoon, mainly at eastern terminals. Non-VFR also possible Monday afternoon/evening in showers/thunderstorms. && .MARINE... Northeasterly winds will persist over the lake through tonight, but should remain below 12 knots. Flow will become northwesterly Sunday as a trough crosses the area and onshore flow should persist through the first half of the week. Winds may increase to 15 to 20 knots Tuesday evening through Wednesday morning, and a Small Craft Advisory may be needed if onshore wind speeds trend higher than the current forecast. Otherwise, no marine headlines are expected. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...FZ/Greenawalt NEAR TERM...FZ/Greenawalt SHORT TERM...Maines LONG TERM...Maines AVIATION...FZ/Greenawalt MARINE...Maines
National Weather Service Hastings NE
638 PM CDT Sat Jun 12 2021 ...AVIATION UPDATE... .DISCUSSION...(This evening through Saturday) Issued at 310 PM CDT Sat Jun 12 2021 Overall...a fairly nice day across the local area with sunny skies, seasonably warm temperatures and low dew points. In the upper levels of the atmosphere...high pressure across the the desert southwest is expected to expand northeastward over the next few days...with southerly flow at the surface gradually increasing dew points across the area. This will result in a rapid return well above normal temperatures...with lower 90s returning tomorrow...gradually increasing to mid and upper 90s by the middle of next week. A weak cold front could then bring a slight cool down late next week. At the same time...multiple disturbances are expected to round the top of the ridge and clip the local area...bringing multiple small chances for thunderstorms to the region. The overall best chance for thunderstorms appears to be with an MCS rounding the ridge Sunday night...bringing a fair chance for thunderstorms to areas west of Highway 281...with the main focus expected to be just west of the outlook area where a marginal risk for severe weather exists Sunday night. Given that the forecast was dry for this time period just 24 hours ago...confidence isn`t the highest in precip locally...and capped chances at 40 percent across our western counties. That said...more and more models are capturing this MCS...with the NAMnest, NAM and HRRR all clipping the western half of the local area Sunday night. If strong or severe thunderstorms do impact our area...winds appear to be the primary concern Sunday night...with a lesser threat of hail...although that threat is non-zero given the elevated instability in place across the local area. Thereafter...additional multiple disturbances will round the ridge and bring small chances for thunderstorms again Monday night, Thursday night and Friday night. These chances appear a bit more spotty than Sunday night...and are much less confident. So overall...expect warm temperatures to return with multiple small chances for thunderstorms...although it is very possible parts of the local area will not receive any precip over the course of the next 7 days. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday) Issued at 636 PM CDT Sat Jun 12 2021 No significant weather. VFR conditions will prevail through the period with hardly a cloud in the sky. Winds will gradually veer from ESE to S and generally remain between 5-10kt. Confidence: High. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ DISCUSSION...Rossi AVIATION...Thies
Area Forecast Discussion
National Weather Service Goodland KS
952 PM MDT Sat Jun 12 2021 .SHORT TERM...(This evening through Monday night) Issued at 231 PM MDT Sat Jun 12 2021 500mb RAP analysis and satellite imagery showed west to southwest flow over the High Plains, with a broad ridge spread over the CONUS. An area of high pressure could be seen over west Texas and southern New Mexico. Sunny to mostly sunny skies were observed across the region this afternoon, with fields of cumulus clouds along and south of Interstate 70. At 2 PM MT, southerly winds were at 10 to 15 mph, gusting around 20 mph, and temperatures were mainly in the 80s. For tonight, the upper ridge begins to amplify along the Rockies as upper high pressure moves further into the Desert Southwest. Temperatures fall into the low/mid 60s under mostly clear to partly cloudy skies. A disturbance rotates around the ridge overnight, generating storm chances south of the area. There will be a brief window between roughly 3 AM and 7 AM MT that a few storms could develop in the southeastern portion of the region (generally Logan and Gove counties), but severe weather is not expected. On Sunday, the ridge builds along the Rockies and Plains as a trough deepens along the west coast. This results in the start of a warming trend, with highs in the upper 80s and low 90s. Meanwhile at the surface, high pressure gradually pushes eastward. While the ridge axis straightens along the Rockies midday, moisture increases and a few storms could fire off the Front Range by the late afternoon. As this activity progresses southeast, additional storms may develop along a cold front situated in northern Nebraska. This second area of thunderstorms is shown to track east southeast through western Nebraska, forming a cluster, and crossing the region late Sunday night into early Monday. At this time, confidence in storms occurring is low. However, shear of 20-35 knots, as well as moderate lapse rates and instability, suggest that a few strong to severe storms are possible if storms do in fact occur. The favored area for severe weather is generally west of a line from McCook, NE to Gove City, KS. Damaging winds are the primary threat, with a lesser threat of large hail. With PWATS in the 1 to 1.5 inch range, would need to monitor for heavy rainfall as well if storms develop. Again, confidence is low. Otherwise, temperatures fall into the low to mid 60s once again. Storms may linger into Monday morning, followed by decreasing cloud cover and sunny skies. Northwest flow prevails on the eastern side of the upper ridge which remains centered along the Rockies. Temperatures continue to warm, reaching the low 90s region-wide. Another disturbance rotates around the ridge Monday night, generating precipitation chances just to the northeast of the region. Have kept the forecast dry for now thinking the ridge will suppress activity, but will monitor for the potential that chances need to be brought south. Lows range in the 60s. .LONG TERM...(Tuesday night through Saturday) Issued at 234 PM MDT Sat Jun 12 2021 Hot, warmer than average temperatures around the century mark, will dominate the Long Term period from Tuesday through Thursday prior to the passage of a cold front on Friday that brings temperatures back closer to normal for this time of year on Saturday. The high amplitude upper ridge over High Plains region on Tuesday moves into the central U.S. on Wednesday as it begins to flatten in response to the upper low center moving eastward across southern Canada. While the upper ridge may flatten, the large upper high over the western U.S. remains centered over the 4-corners region through Thursday. As the low continues across Canada with a series of individual short waves circulating through the Upper Midwest and Great Lakes region, a weaker ridge reamplifies briefly further west over the U.S. Weakly northwest flow aloft over the central High Plains will usher in a series of short waves aloft that move east of the Rockies and across the High Plains late each day as well as a cold front that moves through the region early Friday to help bring down the hot temperatures by next weekend. With the upper ridge and high center over the region, temperatures will remain hot with highs in the mid 90s to the century mark on Tuesday through Thursday with some relief to come on Friday behind a cold front. Highs Friday will range from the mid 80s to lower 90s with mid to upper 80s on Saturday. Relative Humidity values are not expected to be as high as they have been over the last week, so the Heat Index values will stay close to the ambient air temperatures through the hottest days. Dry conditions are expected through the day on Thursday with a slight chance of thunderstorms showing up late Thursday as a weak short wave trough moves through the upper flow ahead of the cold front expected early Friday. There is a slightly better chance of thunderstorms on Friday and Saturday afternoon and evening as slightly stronger short wave troughs move across the region. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) Issued at 950 PM MDT Sat Jun 12 2021 From a pattern recognition standpoint.. increasing moisture and SE-SSE low-level flow would suggest some potential for sub-VFR ceilings AOA sunrise Sunday morning (mainly at the GLD terminal).. though confidence is low. Otherwise, VFR conditions are anticipated to prevail through the TAF period.. with SSE to SE winds at 10-15 knots.. increasing to 15-20 knots Sunday afternoon. Thunderstorms.. perhaps severe.. may approach the region from the north near the end of the TAF period (~06Z Monday). && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...JBH LONG TERM...LOCKHART AVIATION...VINCENT
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
851 PM CDT Sat Jun 12 2021 .UPDATE... Updated for evening discussion. && .DISCUSSION... The potential for any severe weather has ended. However, an outflow boundary in western Alabama pushed convection into east central Mississippi. Have increased pops and cloud cover over our eastern most counties the next several hours to account for this activity which is not expected to push much farther west before dissipating. Satellite imagery shows only a few high thin cirrus elsewhere over of our CWA. /22/ Prior discussion below: Tonight and Sunday: Convection has been slow to develop in the south as low level inversion has yet to be overcome in most places. To the north, strong subsidence in the wake of morning MCV passage has suppressed the CU field through much of the day with visible imagery only now beginning to show some. Based on latest satellite trends, the best convective potential going into the evening will be over the southeast. With the ridging continuing in the west and northerly mid level flow over the area, not much airmass change will occur through Sunday. While the low level inversion will drastically limit convective potential in the west, ridging aloft over the mid MS valley may begin to limit shortwaves/convection dropping south in the flow. The HRRR seems to indicate this with little convection in recent simulated runs. /GG/ Monday through Saturday: Starting off the new work week, the flow aloft will become northerly as a stout ridge over the Rockies amplifies and tilts eastward. A sequence of shortwave troughs rounding the ridge axis and diving south will reinforce a generally drier pattern, while at the surface a weak "cold" front will be marked by lower dew points and higher surface pressure. POPs will be focused along the Gulf Coast in the first half of the week, trending to below mentionable values by Wednesday and Thursday. Guidance remains in fairly decent agreement with this overall pattern, and a consensus blend of forecast elements looked reasonable. Before the front arrives, daytime max temps in the lower to mid-90s can be expected on Monday and Tuesday. Combined with lingering humidity, dangerous heat conditions are possible mainly south of I-20 on Monday and could develop again on Tuesday. For the back half of the work week, the upper-level flow looks to break down some as the axis continues to shear and tilt to the east and a deeper trough dives into the Upper Midwest region. While all this is going on in the westerlies, a broad area of showers and storms over the Bay of Campeche in the southwestern Gulf of Mexico should continue to wobble in that vicinity for a few days before slowly advancing northward. These broad systems are hard to predict in fine detail, but the environment will generally support some organization over the next few days. A Tropical Depression is possible to develop within the circulation, and that potential will have to be monitored. It is still too early to pin down any potential impacts around the central Gulf Coast region, but some increased chance for heavy rain and stronger winds will exist along the Gulf Coast near the tail end of the current 7-day forecast. Stay tuned for updates throughout the week, especially if traveling along the Gulf Coast late this week and early next week. /NF/ && .AVIATION... 00Z TAF discussion: Radar showed a band of TSRA in western Alabama that may spread west and come in vcty of MEI by 02Z. This activity is expected to remain se of GTR and dissipate before reaching PIB-HBG. Otherwise, VFR conditions are expected to prevail through Sunday afternoon. There is the potential for TSRA to come in vcty of the eastern and cntrl TAF sites by 21Z Sun. /22 && .PRELIMINARY POINT TEMPS/POPS... Jackson 74 92 74 93 / 8 45 15 21 Meridian 72 92 72 92 / 75 42 14 24 Vicksburg 75 93 75 93 / 8 38 15 19 Hattiesburg 74 93 74 93 / 14 43 19 44 Natchez 75 92 74 92 / 9 38 19 29 Greenville 74 93 74 91 / 9 33 14 13 Greenwood 73 92 73 92 / 12 48 14 13 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ NF/22/GG
Area Forecast Discussion
National Weather Service North Platte NE
653 PM CDT Sat Jun 12 2021 .SHORT TERM...(This evening through Sunday night) Issued at 320 PM CDT Sat Jun 12 2021 Moisture across wrn KS this afternoon is progged to return north into wrn Nebraska late tonight and Sunday afternoon. This is the result of sfc high pressure across ern SD/ern Neb moving south and east into Missouri by Sunday afternoon. The models are in good agreement showing sfc dew points across wrn Nebraska rising into the low to mid 60s Sunday afternoon. The short term model blend backed by the HREF, NAM12 and NAMnest all show a fairly robust area of outflow dominant thunderstorms forming early Sunday evening. The resultant cold pool from the outflow and moist southerly inflow would appear to drive storm development south and east through swrn and scntl Nebraska. POPs for Sunday evening are set at 40 percent. This is less than the short term model blend which suggested likely POPS of 60-70 percent. There a few factors which could limit convection. One limiting factor is the lack of synoptic scale forcing. A weak subtropical disturbance across nrn AZ this afternoon should lift north through Colorado/WY tonight and then move east Sunday as it rounds the top of a building upper level ridge centered over NM this afternoon. The forcing from the disturbance appears to be very modest. Another potential problem is the models may be too strong and too fast with moisture return. Lastly, the GFS, ECM and RAP models which are different from the convection allowing models listed above, generate much less convective coverage. On the other hand, there is an excellent focus for storm development. A Pacific high pressure system and associated sfc cold front should drift through SD late tonight and be located near or just north of the SD/Neb border Sunday afternoon. Temperatures aloft at h700mb are also fairly cool, near 11C, suggesting a weak cap will be present. Given the weak winds aloft, 20kts at h500mb, the threat of supercell development is low. The bulk effective shear, the result of strong inflow, is 35 to 40 kts and BUFkit suggested briefly severe storms which would quickly evolve into a multicell system. SPC suggested a marginal or 5% severe weather risk Sunday evening. .LONG TERM...(Monday through Saturday) Issued at 320 PM CDT Sat Jun 12 2021 Northwest flow aloft develops tonight and continues through Wednesday. The GFS suggests the potential for storms to develop off the Black Hills or the Big Horns Monday which would certainly be steered through ncntl Nebraska Monday night. Chance POPs are in place for this event. The ECM and NAM are mostly silent with storm development so forecast confidence is on the low side. The rest of the forecast contains isolated thunderstorm chances at times. The notable feature of the extended forecast is temperatures in the mid and upper 90s Wednesday and Thursday. The models are in good agreement warming h700mb temperatures to around 17C both days. Although mixing heights would probably remain below that level, temperatures should rise well into the 90s Wednesday- the warmest day. A Pacific cold front moves part way through wrn and ncntl Nebraska Thursday and just srn Nebraska heats up. A check on heat indices indicates Wednesday will be a potential Heat Advisory day but only marginally so with dew points in the lower 60s. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 648 PM CDT Sat Jun 12 2021 VFR conditions will prevail across western and north central Nebraska tonight into Sunday. Winds will generally be around 10 kts or so from the south to southeast. Some chance for thunderstorm development late Sunday afternoon across northwest Nebraska. Those storms would then move southeast across western Nebraska Sunday evening. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION...Taylor
Area Forecast Discussion
National Weather Service Pueblo CO
639 PM MDT Sat Jun 12 2021 .UPDATE... Issued at 616 PM MDT Sat Jun 12 2021 ...TORNADO WARNING CURRENTLY IN EFFECT FOR NORTHERN CENTRAL LAS ANIMAS COUNTY, DOPPLER RADAR INDICATED ROTATION WITHIN THIS STORM, WHICH IS NEARLY STATIONARY AND SLOWLY MOVING SOUTH. THIS STORM IS CAPABLE OF PRODUCING A TORNADO, ALONG WITH 2.5 INCH HAIL, AND WINDS IN EXCESS OF 70MPH. SEVERE THUNDERSTORM WARNING IS ALSO IN EFFECT FOR NORTHWESTERN LAS ANIMAS COUNTY, SOUTHWESTERN OTERO COUNTY, AND SOUTHEASTERN PUEBLO COUNTY...THIS STORM IS CAPABLE FOR PRODUCING HAIL OF 1.5 INCHES IN DIAMETER IN WIND GUSTS OF 70MPH. PoPs and QPFs have been updated to account for newly developed areas of convection. && .SHORT TERM...(This evening through Sunday) Issued at 254 PM MDT Sat Jun 12 2021 Currently... Some cumulus clouds are forming over the Raton and Southern Sangres. meanwhile, the far southeast plains are seeing dewpoints in the mid- 60s. Latest HRRR runs seem to be drying things out but strengthening southeast winds and high dewpoints suggest otherwise... Rest of Today and Tonight... The upper ridge will continue to build in over the region through the rest of today and tonight, keeping flow west-southwest aloft and advecting more dry air into our mid-levels. Along with that, surface flow over the southeast plains will be from the southeast, which means the lower levels will be getting more moisture, which will assist with instability; dewpoints in the low-mid 60s are already present in Baca County. The moist southeast surface flow will be enhanced orographically, and with the dry mid-levels supporting near-dry adiabatic lapse rates, most of the models are in agreement of convection initiating over the Raton Mesa and southern Sangre de Cristo Mountains by 3-4PM this afternoon. CAPE will be sitting between 1000-1500 J/kg as well, and storms will likely have few problems breaking any cap. Given pretty potent-looking inverted-V soundings, and considering the lapse rates, strong wind gusts of over 60 mph and hail up to 1 inch in diameter will be possible with these initial storms. As storms head further east towards the Kim area between 4-6PM, the environment will start looking a bit more favorable the further east the storms move. CAPE around Las Animas County is expected to sit between 1500-2000 J/kg, with bulk shear topping off over 30 knots. Overall, shear and instability will be more supportive of stronger storms, and hazards in this area will likely increase to 70 mph wind gusts and 1.5 inch hail as possible threats. Hodographs appear to still be pretty straight, and although there is some SRH present in the environment, the tornado threat is relatively low, although still non-zero given the shear profile. Finally, storms will head towards Baca County after 6-7PM, where there will be higher CAPE (2000+) along with better shear and increased environmental helicity. The wind and hail threats will continue, but with the increased parameters there is the chance for an isolated tornado to form. Severe thunderstorm chances diminish greatly after 8PM or so, but a few weaker residual storms could stick around for a few extra hours. Confidence in storms reaching Baca county has fluctuated over the last several hours, with some short-term models (looking at the HRRR specifically here) have been coming in dry for the last few runs, suggesting that storms may have a problem breaking the cap out there and accessing the stores of instability available. Will monitor going forward. While the ingredients for stronger storms are still present in Baca County (CAPE, shear, helicity, etc.) there is rising confidence that storms may unable to break that cap. So overall, while confidence in longer lived storms out east has decreased, if storms do manage to persist out there, they will likely be strong to severe in nature. Other than the main severe threat, there is a low-end chance for some weaker storms to form near Pueblo and the highway 50 corridor, where the main concerns would be gusty winds. Temperatures are expected to be above average once again, with high-80s to low-90s forecasted over most of the area. Lows tonight will dip into the 40s over the valleys, but over the plains things should stick around the low-60s. Sunday... On Sunday, a disturbance to the flow will pass through the upper high over our area, bringing some increased ascent to the I-25 corridor and adjacent areas, increasing chances for more widespread thunderstorms during the afternoon hours. The wind shear setup will be similar to today`s with moist southeast flow at the surface contributing to higher moisture content, while at mid levels more westerly flow will advect in dry air and assist in steepening mid- level lapse rates. Bulk wind will also increase from today, hitting 30-45 knots in places over the southern I-25 corridor. CAPE should be more widespread thanks to the influx of 50s-60s dewpoints expected at the surface, so most of I-25 will be sitting near 1500 J/kg by Sunday afternoon. However, a surface inversion and decent amounts of CIN could limit not only thunderstorm extent but also the potential strength, so these conditions will have to be watched going forwards. Should a thunderstorm overcome these two factors and reach its full potential, it would likely become a supercell, capable of producing large hail, severe outflow winds, and a tornado or two. .LONG TERM...(Sunday night through Saturday) Issued at 254 PM MDT Sat Jun 12 2021 ...Heating up with another uptick in thunderstorms late week into next weekend... Thunderstorms will continue into the evening hours across the southeast plains as one or more convective clusters develop across the plains as the low level jet intensifies. With MlCAPE around 2000 J/kg and deep layer shears around 30-40 kts, one or two severe storms will be possible into the evening hours. LCLs look a little higher than the previous day, so still think primary risks will be large hail and damaging winds into the evening hours. However with such stout CAPE aloft, and decent low level shear can`t rule out a brief tornado. The Palmer Divide and Raton Ridges tend to be the higher probability locations due to terrain induced boundaries where resident surface vorticity can get stretched. So although a low probability event, it will still bear close watching. Best low level moisture looks to be across the Palmer Divide right now, so that may be the higher probability location. High res models drive a westward propagating outflow boundary into southeast CO overnight originating from convection in KS and have maintained some isolated pops across far eastern areas to account for the potential of thunderstorms to linger past midnight. Monday...the upper high will continue to build northward over the Rocky Mountain region and temperatures will heat up once more...particularly out west. Nam12 maintains some higher dew points across the plains vs other models which do not appear to resolve the Sunday night convection/outflow boundary. Deep layer shear weakens with the upper high overhead but with upslope flow can`t rule out an isolated thunderstorm across the southeast mountains/adjacent plains on Monday. Almost due southerly storm motions should keep any isolated activity tied to the mountains, as the southeast plains appear capped for now. GFS is more robust with mixing out the surface dew point in spite of southeast low level flow and therefore keeps all of southern CO dry. Plan to keep some isolated pops in and near the southeast mountains for now and will need to watch how this evolves. With high LCLs, around H6, gusty winds and lightning would be the primary storm risks. Upper high stays locked in over the 4 corners region through mid to late week, gradually moistening in the mid and high levels as recycled moisture from thunderstorms across the western U.S. get entrained within the upper high. Southeast plains may see periodic intrusions of low level moisture from westward propagating boundaries originating from central plains MCSs...with GFS advertising the next one for Monday night. However low level moisture is advertised to mix out each afternoon with temperatures soaring to around 100 across the plains again through mid week. Overall, will keep isolated thunderstorms in the forecast each day mainly for the mountains, with an uptick towards mid to late week as mid and high level moisture increases. An upper trough to the north will clip through the the northern high plains, shifting the upper high westward and allowing a cold front to drop through the southeast plains late in the week. This will bring a cool down for Friday and another potential uptick in thunderstorms across the southeast mountains and adjacent plains into next weekend. With northwest flow over the region, we could see another round of strong to severe thunderstorms along the I-25 corridor if low level moisture return is sufficient Friday and southeast surface winds beneath northwest flow aloft is a classic severe weather pattern for southeast CO. -KT && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 254 PM MDT Sat Jun 12 2021 VFR conditions are expected at KALS, KCOS, and KPUB over the next 24 hours. There is a low chance that a thunderstorm could develop near KPUB around 00-02Z tonight, but confidence is low enough to not include it in the TAFs. If a storm were to form nearby, gusty, erratic winds and MVFR conditions from heavy rain would be possible. Overnight tonight KCOS could get some low clouds that could lower flight category from cigs, but it will largely depend on how strong the southeasterly flow gets later tonight, so left things at VFR for now. Winds at KCOS and KALS will be gusty, up to around 25 mph, this afternoon through around 03Z tonight. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...STEWARD SHORT TERM...GARBEROGLIO LONG TERM...KT AVIATION...GARBEROGLIO
Area Forecast Discussion
National Weather Service Blacksburg VA
720 PM EDT Sat Jun 12 2021 .SYNOPSIS... Expect one front to move south of the area tonight, while another front sinks southeast to region by Monday morning. This front will bring a return of less humid weather as high pressure builds in to the Mid Atlantic region for the middle of the week. && .NEAR TERM /THROUGH SUNDAY/... As of 715 PM EDT Saturday... Big decrease in rain and thunderstorm activity within the last hour or so as instability wanes. Only a few remaining showers along the western slopes of West Virginia, extending down to northwest North Carolina. Expect most of this to continue to diminish through the evening. Fog and low clouds still expected to develop overnight and into the early morning hours. As of 230 PM EDT Saturday... Expect bands of showers/few storms across the west through this evening then foggy overnight, followed by a few more storms Sunday... High-res convective allowing models handling setup this afternoon fairly well with corridor of deep moisture convergence and some upper difluence from the Greenbrier Valley/Alleghanys south through the New River Valley, into the NC mountains/foothills. The HRRR has been so far doing the best with this, and hangs onto showers/few storms into this evening in the same location. Downpours are limited to shorts amount of time due to speed and size of cells, so at the moment do not see a need for flash flood watch, but not out of the question to have localized flooding, especially if storms train or move slower over an urban area like Galax/Radford/Wilkesboro. Convection wanes fast this evening to just showers then limited coverage by 10pm, to nothing overnight. Fog and low clouds are likely overnight as drier air aloft works in while boundary layer/surface stay moist. Could see a dense fog advisory for the mountains, but will let the next shift examine parameters and see how we clear out if at all overnight. Sunday, we will be a northwest flow aloft with upper divergence, and limited upper forcing per models. At the surface a cold front works from Ohio/KY Sunday morning slowly into the central Appalachians mid afternoon. By late in the afternoon, models develop convective induced vorticity across the Alleghanys. With a little more wind speed aloft, a marginal risk for severe storms exists mainly along/north of I-64 with best threat for severe storms further north. Limiting factor could be the low clouds/fog early but models showing more sunshine by midday, though the Nam is a little higher on cloud cover. Lows tonight will be slightly lower than this morning with lower to mid 60s most places. Warmer Sunday with more sunshine, with 80s areawide, except 70s higher elevations. Forecast confidence in temperatures and wind are high, pops through this evening high, but average on threat and coverage of storms Sunday with best chance along/north of BKW-LWB-ROA. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... As of 230 PM EDT Saturday... Chances of rain Sunday night...Monday and Tuesday drier... A cold front passes overhead late Sunday and brings chances of rain showers for the whole area, but showers are more likely for those west of the Blue Ridge towards eastern WV. A cutoff upper low forms over eastern Canada turning our upper flow to the northwest. This advects cooler, dry, continental air into the Mid-Atlantic. Temperatures will drop marginally, to near normal for mid- June, but humidity will be less. More impactfully, chances for showers on Monday and Tuesday will be low as there is no deep moisture to tap into as there was last week. Any showers that form up will be light and likely short lived. With the drier air aloft, skies will clear up. Monday and Tuesday will be sunny with highs in the 70s west of the Blue Ridge, 80s east. It will feel more comfortable outside as dewpoints also drop and relative humidities in the afternoons will be in the 40-50% range. Lows will be in the 50s and low 60s both nights. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 230 PM EDT Sunday... Quieter weather through the week, with a front approaching over the weekend... Drier air from northwest flow as well as surface high pressure will keep the skies inactive for the second half of the week. The nights could get rather cool, with lows on Wednesday and Thursday in the mountains reaching down into the 40s. On Saturday another upper low makes its way into eastern Canada, and brings with it an associated surface low and trailing cold front. PoPs start to come back up again on Saturday with the chance for some pre-frontal showers. Next weekend will be the most active weather we`ll have seen since the start of the week. && .AVIATION /23Z SATURDAY THROUGH THURSDAY/... As of 715 PM EDT Saturday... VFR this evening with most shower/storm activity beginning to diminish. Cigs and vsbys get lower overnight thanks to a stable but moist low level airmass. Could see dense fog at LWB/BCB/BLF, but perhaps even LYH, but confidence is not high enough for LYH yet. So looking at IFR or worse at all taf sites overnight. Will see cigs/vsbys improve to VFR between 12-15z. Another front pushes south for Sunday. Any storms on Sunday will likely hold off til after 18z, and mainly northwest of a line from BLF-BCB-LYH. Confidence is not high enough to mention in the TAFs yet. High confidence on poor cigs late tonight. Otherwise average confidence for ceiling, visibility and wind. Extended Aviation Discussion... Mainly VFR into Thursday 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...WP NEAR TERM...BMG/WP SHORT TERM...VFJ LONG TERM...VFJ AVIATION...BMG/WP