Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/12/17

Area Forecast Discussion
National Weather Service Albany NY
953 PM EDT Fri Aug 11 2017 .SYNOPSIS... A warm front and an upper level disturbance will bring some showers and thunderstorms to the region tonight. A cold front will slowly approach the region from the west tomorrow with more showers and potentially strong thunderstorms in a humid air mass. The cold front will move east of the region Saturday night with a slightly cooler, but a drier air mass building in for late in the weekend into Monday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Updated forecast to track area of precipitation moving through the CWA. Have used radar data and HRRR to get a handle on movement of showers. As noted in the afternoon package, this activity is supported by 250 hPa jet streak of 75-85 kts with a good plume of upper level divergence. A few cloud to cloud strikes noted a little earlier this evening in Ulster County. 00Z ALY sounding shows about 500 j/kg of most unstable CAPE available. So still allowing for a slight chance of TSRA with activity through the night. Sounding PWAT was 1.44 inches which is about one standard deviation above normal. For the most part rainfall rates across Ulster County have been around 0.25 inch. However, the New York State Mesonet site at Claryville did show about 1.20 inches between 830-930pm. So, generally around 0.25 inch, but up to one inch per hour possible in convective elements. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Tomorrow...A lull in the showers/t-storms is possible in the mid to late morning with the warm front slowly moving through the forecast area. Eastern NY and western New England may get into a mini-warm sector by the early afternoon. Attention shifts to the approaching cold front from southeast Ontario and the eastern Great Lakes Region. There will be a lot of cloud cover around in the morning with some spotty light showers. The 12Z NAM and GFS are hinting at some breaks in the cloud cover with some heating. If this heating occurs, surface-based instability values of 1000-2000 J/kg may be realized by the afternoon, if sfc dewpts in the lower to upper 60s occur. Both the NAM/GFS are showing some steepening of the mid level lapse rates by the mid to late pm in the 6.5C-7C/km /700-500 hPa layer/ and the deep layer 0-6 km bulk shear increases to 30-40+ kts. Some discrete organized convection is possible if the destabilization occurs. There is decent west to southwest flow in the mid-levels, so multicells orienting into a line or two may be possible. It looks like the initial storms could fire with a pre-frontal trough. The SPC Day 2 has the entire area in a Marginal Risk for severe thunderstorms. We added enhanced wording for gusty winds and small hail to the gridded forecasts. Some heavy rainfall is also possible, though a little drying in the wake of the warm front and the short- wave tonight may lower PWATS back to 1-1.5" for Saturday. The risk for some strong to potentially severe thunderstorms looks greatest between 18Z to 01Z/SUN. Any severe convection would be from bowing segments yielding damaging winds, and large hail. Highs on Saturday will generally be in the mid 70s to around 80F over the hills and in the valley locations with mid 60s to lower 70s over the mountains. Saturday night...The showers and thunderstorms will diminish early on as the cold front pushes through the region. The showers may hang on the longest across the southern Adirondacks and the western Mohawk Valley due to the differential cyclonic vorticity advection with the upper trough. Weak cold advection occurs in its wake. Some patchy fog is possible across the region with lows falling back into the mid 50s to lower 60s across the region Sunday...The upper level trough axis needs to move through in the morning. Some isolated to scattered showers are possible from the Capital Region north and west, then better mixing and subsidence will occur in the wake of the trough passage. It will be a breezy and less humid to close the weekend with highs in the mid 60s to mid 70s over the hills and mountains, and mid 70s to lower 80s in the valley areas. Some downsloping with west to northwest winds of 10 to 20 mph will allow portions of the Capital Region and the mid Hudson Valley to still reach the lower 80s. Sunday night...Diminishing winds and mostly clear/clear conditions are expected with high pressure ridging in from the Great Lakes Region. Humidity levels will be comfortable, and lows will be in the 50s. && .LONG TERM /MONDAY THROUGH FRIDAY/... In the mean, a broad upper level trough will be in place across the eastern U.S. during the period. Meanwhile at the surface, high pressure will be the dominate feature for most days. For now, the best chance of rain looks like it will be on Tuesday as a weak shortwave trough approaches and transits the region. Even though Tuesday is the best chance for rain, POPS are only slight chance to chance across the area. Otherwise, Monday, Wednesday, and Thursday look dry with increasing sunshine Wednesday and Thursday. Temperatures and humidity levels will be fairly typical for mid August with highs in the low 80s valleys to 60s and 70s higher elevations. Dew points will generally be in the 50s. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... With no observation since 17Z, AMD NOT SKED introduced at KGFL. Area of RA moving into southern forecast area now. Activity has skirted KPOU. In general looking for MVFR condition to develop this evening at all terminals in RA. It is possible that a terminal could experience a TSRA tonight, but not capable of picking the terminal nor the time, so no mention in TAFs. With lower CIGS and VSBYS expect all terminals to experience IFR conditions in the 06-12Z period. For Saturday, area is in marginal risk for severe thunderstorms. At this time, will not introduce TSRA given lack of confidence in specifying time and location. I have covered with VCSH for Saturday afternoon. In time, this will get more specific. Outlook... Saturday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Sunday: Low Operational Impact. Isolated SHRA. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX. Monday Night: Low Operational Impact. Slight Chance of SHRA. Tuesday: Moderate Operational Impact. Chance of SHRA. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. && .FIRE WEATHER... A warm front and an upper level disturbance will bring some showers and thunderstorms to the region tonight. A cold front will slowly approach the region from the west tomorrow with more showers and potentially strong thunderstorms in a humid air mass. The cold front will move east of the region Saturday night with a slightly cooler, but a drier air mass building in for late in the weekend into Monday. The RH values will increase to 85 to 100 percent tonight and Saturday night. The RH values will only fall to 50 to 65 percent Saturday afternoon. The winds will be south to southeast at 5 to 10 mph tonight and south to southwest at 5 to 15 mph tomorrow. The winds shift to the west to northwest at 5 to 15 mph Saturday night into Sunday with the cold frontal passage. Some gusts in the 20 to 30 mph range are possible on Sunday. Showers are likely tonight with isolated to scattered thunderstorms. More showers and thunderstorms are possible Saturday into early Saturday night with the cold front. && .HYDROLOGY... No widespread problems are expected on the main stem rivers the next several days. Showers and thunderstorms will develop tonight through Saturday night, as the next low pressure system approaches from the Great Lakes region with its associated warm and cold fronts. Because of the scattered nature of the convection tonight through Saturday, basin wide rainfall amounts are expected to be three quarters of an inch or less but localized amounts of an inch or more are possible in thunderstorms with local ponding of water on roadways or poor drainages flooding of low lying areas. The showers and thunderstorms will diminish Saturday night with the cold frontal passage. Only additional light rainfall amounts are possible on Sunday for locations north and west of the Capital Region with a few hundredths to a tenth of an inch with the upper level trough. Drier weather returns Sunday afternoon through Monday with high pressure building in. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Wasula NEAR TERM...OKeefe/Wasula SHORT TERM...Wasula LONG TERM...OKeefe AVIATION...OKeefe FIRE WEATHER...NAS/Wasula HYDROLOGY...NAS/Wasula
Area Forecast Discussion
National Weather Service Birmingham AL
648 PM CDT Fri Aug 11 2017 .UPDATE... Aviation Discussion. && .SHORT TERM... This Afternoon and Tonight. Widespread cloud cover and cooler temperatures this afternoon produced a more stable air mass across central Alabama, limiting areal coverage and intensity of convection. More sunshine across the far southern counties has produced more thunderstorm activity, but the stronger storms have been south and west of Montgomery and Troy. Radar shows a line of stronger storms west of Troy and there may still be a limited threat for heavy rainfall with this activity as it tracks eastward, and possibly sends an outflow boundary northward towards Montgomery. The flash flood watch has been reduced to areas along and south of I-85 and the expiration time is now 7 pm instead of midnight. Minimal shower and thunderstorm activity expected across central Alabama after 9 pm. The lone exception may be the northwest counties as a cluster of storms over northern Mississippi tracks southeast. Latest HRRR model shows this activity holding together a little longer, so rain chances may need to be raised in future updates. Low clouds and fog likely to develop late tonight. 58/rose .LONG TERM... Saturday through Thursday. As we work into the weekend, the big question will be can the next front push through or does it stall out once again across the area. Most of the models now are keeping the front either across our northern counties and then sliding it north by Sunday, or keeping it north of the area the entire time. The Canadian model is now the only model that still pushes the front through. So will once again trend toward the wetter pattern for the extended as there really is nothing that will push it out of the Southeast. So on a whole look for still above normal precipitation with near normal temperatures for the period. 16 && .AVIATION... 00Z TAF Discussion. Isolated showers are beginning to diminish this evening. There is a decaying line of storms moving into Central Alabama from MS, that could leave a boundary and provide a focus for isolated showers this evening. Will leave VCSH in the forecast for northern terminals through 05-06Z. Low clouds and fog are expected overnight, with IFR conditions by sunrise. Will need to watch for localized LIFR conditions. Cigs/Vis will slowly improve through the morning hours, with broken MVFR cigs through the day. By mid day, expect showers and TS to develop across the north, with activity near MGM and TOI by mid afternoon. Winds will be light/variable or calm overnight, increasing to 5-6kts from the southwest to west Saturday. 14 && .FIRE WEATHER... Above normal rain chances are expected through the weekend and into next week. There are no fire weather concerns. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 72 88 71 88 72 / 30 40 30 50 30 Anniston 72 87 72 89 73 / 30 60 30 60 30 Birmingham 74 89 73 90 74 / 30 40 30 50 30 Tuscaloosa 74 91 73 91 74 / 30 50 30 50 30 Calera 73 89 73 90 74 / 30 50 30 60 30 Auburn 73 88 74 89 74 / 30 60 30 60 30 Montgomery 75 91 75 92 75 / 30 60 30 60 30 Troy 73 90 74 91 74 / 30 60 30 60 30 && .BMX WATCHES/WARNINGS/ADVISORIES/... Flash Flood Watch until 7 PM CDT this evening for the following counties: Barbour...Bullock...Lowndes...Macon...Montgomery... Pike...Russell. && $$
Area Forecast Discussion
National Weather Service Taunton MA
1023 PM EDT Fri Aug 11 2017 .SYNOPSIS... Low pressure from the Great Lakes moves E/NE tonight and Saturday. This will draw a warm front up across S New England by Saturday morning, then swing a cold front through Saturday night. With the remainder of the weekend dry, some shower chances emerge through the week, mainly Tuesday, but nothing of a wash out. Overall seasonable conditions with low humidity. However, long- range, may see warmer summertime conditions return. && .NEAR TERM /THROUGH SATURDAY/... Made further changes to the forecast this evening. Primary changes were to rainfall timing, which looks to be well handled by the majority of the near-term guidance. expecting mostly showers across the western half of southern New England through about 2 AM, then overspreading the rest of our region thereafter. Minor tweaks to temperatures to reflect observed trends. Previous Discussion... Turning wet around midnight. Fair amount of theta-E moisture associated with a mid-level vortmax pivoting round the broader troughing regime across the region. Precipitable waters rising especially along the S-coast with values up to 2-inches, some early indications simply given the more soupy airmass pushing into the region with lower clouds and reduced visibility. Have made some modifications to the forecast. A marginal setup given a strong influx via SW flow of higher theta-E within a conditionally unstable airmass. Mainly focused on the rain which has the potential of being heavy, the greater risk of which is along the S-coast in lock step with a H925-85 theta-E gradient along which low-level winds are to a degree convergently focused (though the stronger convergence, if the RAP is correct, remains mainly over the waters). The possibility of a rumble of thunder, mainly leaning higher categorical of rain with lesser threat of thunder. Prevailed with "heavy rain" wording in the forecast. The S offshore Islands at greatest risk, especially Nantucket, of heavy rain. The over-running setup, went with LIKELY to DEFINITE PoPs. A word of caution. A lot of energy and subsequent area of low pressure streaming into the interior NE CONUS parent with the mid to upper level low out of the Great Lakes Region. Though the lower heights are also pulling N the sub-tropical warm front just S/E offshore. Two neighboring areas of low pressure, as we`ve seen before in this situation before someone is going to see very little if anything subsequent of a subsidence wedge. Looking at a region SW to NE across S New England. Places such as Boston up the NH/ME coastline may only see wet-weather associated with the main vortmax sweeping through around midnight into the early morning hours on Saturday then very little after that. Something to monitor as we go through the next 24 hours. Mild night, soupy along the S-shoreline with a greater propensity of low clouds and fog. Lows in the 60s. && .SHORT TERM /SATURDAY NIGHT/... Saturday morning... The first shortwave moves past New England during the morning. This may be enough to move the warm front through our area and bring us a more humid airmass. Expect showers to continue during the morning, and then most will taper off as the warm front moves past. Saturday afternoon and night... The second shortwave approaches from the Midwest Saturday evening and crosses New England toward Sunday morning. The cold front associated with this shortwave will cross NY and PA during the afternoon and then cross New England Saturday night. Difficult to determine the presence of a pre-frontal surface trough ahead of the front, one that could be a focus for convection to fire. Model theta-e fields do show a theta-e ridge crossing the Northeast Corridor Saturday afternoon/evening. After a short break early Saturday afternoon, expect a second round of showers mid to late afternoon. Totals are forecast at 47-51 after 18Z, with lifted index sub-zero. So along with the showers, we should also have a few thunderstorms. Winds aloft are rather light for generating any damaging gusts, although 500 mb winds do increase to 50 knots around midnight. This is a little late for us regarding any severe weather. So at this time we are not thinking of any severe storms in our area. Total rainfall amounts through Saturday night should generally range between one-half and one inch, with the greatest amounts toward the south coast, including the Cape and islands. Once the cold front moves through, expect winds to shift out of the west and showers/storms will move off. && .LONG TERM /SUNDAY THROUGH FRIDAY/... */ Highlights... - Overall dry pattern, some shower chances, but nothing drenching - Seasonable conditions with low humidity overall - Long-range pattern change, could see warmer temperatures return */ Overview... A downstream cascade of outcomes. Within the mid- to upper-levels, progressive deep troughing over N-Central Asia acts to cut off an area of low pressure near the Kamchatka Peninsula. Both continuing E subsequently flip the dipole over the N Pacific with lower pressure building into the Aleutians and high pressure developing over the Gulf of Alaska. The subsequent breakdown seemingly has implications downstream with flow becoming more zonal across the CONUS with less amplification of preferred troughing over our region. Subsequently there are indications of a slight warm-up across the region at times interrupted by continued weak Pacific-origin impulses and chances of wet-weather. Overall though it would appear that the sub-tropical airmass and more sultry air is buffered offshore, thus conditions do look to remain comfortable. Will hit on specifics below. */ Details... Sunday into Monday... Lingering showers early Sunday, turning dry. Sunday morning cool frontal push along with a mid-level trough axis, much drier air builds into the region. Increasing confluence of mid to upper level flow aloft, surface high pressure builds across the region Monday, light winds contributing to onshore sea-breezes. Scattered to broken cloud decks associated with some mid-level energy through the confluent flow. Overall a dry period of weather with near-seasonable temperatures and low humidity. Tuesday into Wednesday... Possibly our next best chance of wet-weather. Confluent mid to upper level flow becoming lax, deeper troughing and attendant vortmax energy sweeping the region. Model forecast guidance mixed as to whether the offshore sub-tropical quasi-stationary boundary lifts back to the N or rather shower / thunderstorm activity developing over the N/W interior of the NE CONUS impacts our region. Could be a situation where S New England is wedged-out within subsidence being neighbored by two areas of lower pressure. Will keep the mention of chance PoPs on Tuesday given better moisture availability, also lean warmest conditions for the week. Wednesday looks to remain dry with the majority of forcing/lifting mechanisms swept through the region behind which cooler, drier air builds in. Thursday into Friday... Dry, near-seasonable, slight warm-up by day. High pressure building across the region yet again. Cooler airmass in place on Thursday which is quickly replaced Friday by warmer, S flow. Both days the winds have the potential of being light to allow onshore sea-breeze winds. Increasing clouds late on Friday with the chance of showers overnight ahead of a warm-frontal boundary. Weekend... Potentially wet on Saturday, dry Sunday. A warm front looks to lift through the region, hanging along the coast up against the cooler waters. S flow increasing as the mid to upper level pattern exhibits less troughing, looking at a possible slow build up of heat and humidity with the chances of showers and thunderstorms into early next week. Way out there, very early to say, so a low confidence forecast. But if the mid to upper level pattern is changing as was addressed in the overview, the pattern we`ve seen as of late of continued N flow of cooler and drier air may become relaxed allowing warmer Summer conditions to return as hinted by the Climate Prediction Center`s 6-10/8-14 day outlooks. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Saturday Night/... Tonight...Moderate confidence. VFR lowering towards MVFR into morning for most terminals. South coastal terminals in a IFR-LIFR soup already. Light S winds. Light RA spreading SW to NE overnight, could be RA/+RA along the south coast by morning. Saturday...Moderate confidence. MVFR lifting back to VFR across the interior, but the IFR-LIFR soup continues to plague S-coastal terminals. ACK at the highest risk of remaining in low clouds all day. Increasing S winds. -RA and possible TSRA encroaching from the S/W late, potentially impacting the W terminals, sliding along the S-coast into evening. From roughly BDL-ORH and terminals N/E up through BOS may have no issues at all. Saturday night... VFR lowering back down to MVFR briefly across the interior before winds shift back out of the W. IFR-LIFR continues to plague S-coastal terminals, clearing out towards Sunday morning with the wind shift. KBOS Terminal... Will keep with VFR lowering to MVFR shortly after midnight with -RA. Feel the terminal may not experience much in the way of issues through the TAF period over the next 30 hours. KBDL Terminal... VFR lowering to MVFR with likely rain around midnight. There is the possibility of RA/+RA though feel the better risk will hold to the S of the terminal overnight. Though no mention, there is a risk of TSRA late Saturday from the W/SW. Outlook /Sunday through Wednesday/...Moderate confidence. Sunday...VFR. Lingering SHRA across S/E coastal terminals, otherwise dry. N/W winds breezy during the day, lax overnight. Monday...VFR. Light winds. Sea-breezes possible. SCT-BKN mid- high CIGs. Tuesday... VFR. S winds, breezy. Possible SHRA/TSRA, better chances N/W. Wednesday...VFR. Winds shifting N/W, initially breezy, becoming light. Sea- breezes possible. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Saturday Night/...High confidence. A Small Craft advisory may be needed on the southern outer waters Saturday night. Southerly winds tonight and Saturday shift from the west later Saturday night as a cold front moves across the waters. Winds remain less than 20 knots through Saturday night. The sustained south flow prior to that may build 5 foot seas on the southern outer water by Saturday night. Showers and areas of fog will bring reduced visibility through much of Saturday night. Outlook /Sunday through Wednesday/...Moderate confidence. Showers clearing out over the waters early Sunday making for a nice weather the remainder of the day, though breezy out of the N/W. For the small boaters especially, can`t rule out gusts up to 20 kts. Will see winds diminish into Monday with high pressure. Monitoring for possible encroaching rain from the S on Tuesday with perhaps some breezy SW flow, otherwise Wednesday looks to be good boating weather with N/W winds behind a Tuesday night cool frontal passage. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...WTB/Sipprell NEAR TERM...WTB/Belk/Sipprell SHORT TERM...WTB LONG TERM...Sipprell AVIATION...WTB/Sipprell MARINE...WTB/Sipprell
Area Forecast Discussion
National Weather Service Cheyenne WY
510 PM MDT Fri Aug 11 2017 .SHORT TERM...(This evening through Sunday night) Issued at 120 PM MDT Fri Aug 11 2017 Forecast challenges with this package deals with severe thunderstorm potential both today and Saturday. Currently...Upper ridge remains stationary over the northern Rockies from northern Idaho to northern Utah into southwestern Colorado this afternoon. Water vapor imagery showing a small disturbance moving through the ridge into south central Wyoming this afternoon thats interacting with low level moisture and the tail end of a stationary front on surface analysis. A stronger low pressure system can be seen on water vapor imagery over north central Montana that will have some impacts on us tomorrow. Latest mesoanalysis showing surface based CAPE up to 1500 J/KG over Converse and Niobrara Counties this afternoon at 1PM. Radar is starting to light up on convection mainly in this area, extending south into northern Platte County. Latest HRRR simulated radar showing the area of convection over Converse County dropping south as the afternoon progresses and this is what the SPC mesoanalysis page also shows with increasing CAPE. We could see a few severe thunderstorms down here in Laramie County late this afternoon just east of Cheyenne if the HRRR forecast comes true. Forecast CAPE up to 1500 J/KG by 23Z across Laramie County. Better chances for severe thunderstorms Saturday as that Montana low tracks southeast into western South Dakota. By late Saturday afternoon, upper low near Rapid City with a cold front moving south into Converse and Niobrara Counties. Afternoon MUCAPE from NAM up to 2500 J/KG. Pretty high shear values as well with northeast surface winds at 10kts and upper level winds at 65kts at 350mbs. Agree with SPCs Slight Risk area they have identified for the Panhandle and would only maybe shift it a little further west into Wyoming. Good shear means we will likely see a few severe thunderstorms with very large hail. Did introduce severe thunderstorms into the weather grids for the Panhandle and extreme southeastern Wyoming for tomorrow afternoon/early evening. Also updated HWO and weather story to reflect current thinking. Sunday may be a little drier with upper ridge starting to move into western WYoming. Most of the precip should be down over Colorado Sunday, but we could see a few thunderstorms coming off the mountains Sunday afternoon, so kept low chance PoPs going. .LONG TERM...(Monday through Friday) Issued at 120 PM MDT Fri Aug 11 2017 Monday...Expect to see a decrease in afternoon and evening shower and thunderstorm coverage as a ridge aloft moves overhead. Still though, enough low and mid level moisture for isolated to widely scattered afternoon and evening showers and thunderstorms. Definite warming trend with more sunshine and a moderating airmass. Tuesday...With a shortwave trough aloft moving overhead in the afternoon, and adequate low and mid level moisture, expect to see scattered showers and thunderstorms develop, especially east of Interstate 25. Wednesday...In the wake of the shortwave trough aloft, will see some low and mid level drying, thus minimal chances for showers and thunderstorms in the afternoon and evening. Warming trend continues with more sunshine and downslope winds. Thursday...Continued mild per thicknesses and mid level temperatures. Flow aloft becomes northwest and with limited low and mid level moisture, minimal chances for showers and thunderstorms. Friday...Continued dry and seasonably mild with the flow aloft backing to zonal, west to east, and limited low and mid level moisture to fuel any showers or thunderstorms. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 510 PM MDT Fri Aug 11 2017 Wyoming TAFS...VFR prevails, with thunderstorms near terminals until 02Z producing wind gusts to 35 knots and again after 20Z on Saturday. Although low stratus and fog are possible at KCYS, confidence is pretty low at this time. Nebraska TAFS...VFR prevails, with thunderstorms until 04Z producing wind gusts to 45 knots. Low CIGS are possible by early Saturday morning, but confidence is rather low at this time. && .FIRE WEATHER... Issued at 120 PM MDT Fri Aug 11 2017 Minimal fire weather concerns as a cool and unsettled weather remains in place across southeast Wyoming and Nebraska Panhandle. Upper ridge over the northern Rockies will keep a northwest flow over the area with disturbances moving across our area from the northwest on a daily basis. Rainshowers and thunderstorms look to occur on a daily basis with these disturbances, so most areas should see measurable rainfall at least Tuesday before drying out towards the end of next week. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...GCC LONG TERM...RUBIN AVIATION...RUBIN/TT FIRE WEATHER...GCC
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
641 PM CDT Fri Aug 11 2017 .AVIATION.../00Z TAF CYCLE/ VFR conditions prevail are and expected through the the 24-30 hour period. While the NAM continues to be more aggressive with low-level moisture Saturday morning, both the GFS and recent time-series of the HRRR suggest lower saturation levels. Have continued the SCT010 grouping for KAUS/KSAT/KSSF sites given the low probability of MVFR ceilings. Some very patchy MVFR/IFR ceilings could occur west across the higher terrain of the Escarpment region but actual TAF sites should remain VFR. will need to monitor HRRR trends overnight to see if KSAT/KSSF could briefly go MVFR in the 11-15Z time-frame. OVerall confidence is low at this time. Surface winds will be south to southeast at 5-10 knots overnight with some periodic gusts to near 15-20 knots near KDRT by Saturday afternoon. && .PREV DISCUSSION... /ISSUED 153 PM CDT Fri Aug 11 2017/ SHORT TERM (Tonight through Saturday Night)... The mid and upper level ridge will continue to stretch from west to east across the southern U.S. through the weekend. The ridge axis is just about right over south central Texas, so we expect little change in conditions from today through Sunday. A little drier air will work into the northern portions of the area for Saturday and Sunday, so the Heat Advisory area will be scaled back to counties east of Interstate 35 for those two afternoons. LONG TERM (Sunday through Friday)... The ridge begins to break down and thin out, with easterly flow becoming established across the northern Gulf by midweek. This onshore flow will increase PW and allow easterly waves to enter the state. With typical summertime instability already in place, the ingredients will then be present for isolated to scattered showers and thunderstorms. The best chances will be Tuesday and Wednesday across the coastal plains, but many locations in south central Texas will remain hot and dry through the end of next week. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 76 100 76 100 77 / - 0 0 0 0 Austin Bergstrom Intl Airport 75 99 75 100 76 / - 0 0 0 0 New Braunfels Muni Airport 75 99 74 100 75 / 0 0 0 0 0 Burnet Muni Airport 74 97 74 98 74 / 0 0 0 0 0 Del Rio Intl Airport 78 101 78 103 78 / 0 0 0 0 0 Georgetown Muni Airport 76 98 75 98 76 / 0 0 0 0 0 Hondo Muni Airport 75 100 75 102 76 / 0 0 0 0 0 San Marcos Muni Airport 75 99 75 100 76 / - 0 0 0 0 La Grange - Fayette Regional 77 99 76 99 77 / 0 0 0 - 0 San Antonio Intl Airport 76 99 76 101 77 / 0 0 0 0 0 Stinson Muni Airport 76 99 76 101 77 / 0 0 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 7 PM CDT this evening for the following counties: Atascosa...Bastrop...Bexar...Caldwell...Comal...De Witt... Fayette...Gonzales...Guadalupe...Hays...Karnes...Lavaca...Lee... Travis...Williamson...Wilson. Heat Advisory from 2 PM to 7 PM CDT Saturday for the following counties: Atascosa...Bastrop...Caldwell...De Witt...Fayette... Gonzales...Guadalupe...Karnes...Lavaca...Lee...Wilson. && $$ Mesoscale/Aviation...Allen Synoptic/Grids...Oaks Public Service/Data Collection...30
Area Forecast Discussion
National Weather Service Green Bay WI
1046 PM CDT Fri Aug 11 2017 Updated aviation portion for 06Z TAF issuance .SHORT TERM...Tonight and Saturday Issued at 210 PM CDT Fri Aug 11 2017 Cyclonic flow over the region were keeping clouds around along with cooler afternoon temperatures. Various models including the short range runs continue to develop isolated light showers across the area during the remainder of the afternoon, but so far only spots of drizzle or sprinkles were noted. Local radars show light showers over the area, with more numerous showers with isolated storms over Lower Michigan. The HRRR even produces a few light showers over Door County late tonight, where the cyclonic flow may linger a bit longer and some instability contribution with the cooler air flowing over the Great Lakes region. Will leave dry for now due to limited coverage of showers this afternoon. High pressure approaching from the west along with drier air on northwest winds were gradually eroding the clouds or increasing the base height over central and north central Wisconsin early this afternoon. Appears this trend of clearing is lagging so will slow down this trend this afternoon and evening across northeast Wisconsin. Eventually clearing skies and diminishing winds will prevail across much of the area, and allow temperatures to fall. Typical Climatological cool spots of central and north-central Wisconsin may make a run toward the upper 30s to around 40. High pressure settling over the area Saturday will allow abundant sunshine and allow temperatures to return closer to normal. .LONG TERM...Saturday Night Through Friday Issued at 210 PM CDT Fri Aug 11 2017 A fairly stable pattern will be in place across North America over the next week, consisting of a potent ridge slowly moving east over central Canada. Will therefore see mainly quiet conditions until this ridge passes to our east, which will allow the deep layer flow to turn back to the southwest and increase precip chances. Plenty of differences in the models by this time, and prefer a solution closer to the gfs. Saturday night through Monday...Conditions will start out quiet on Saturday night with a large area of high pressure in control. Dry conditions will probably continue into Sunday morning, but clouds will be on the increase as weak shortwave energy moves into the region. This shortwave will move across the region during Sunday afternoon into Sunday night. Progged soundings indicate that the atmosphere will struggle to saturate below 700mb, so cannot see much more that scattered light showers and sprinkles during this time. Clouds will then decrease behind the shortwave for late Sunday night into Monday morning. Scattered high based cu is likely to form on Monday, but precip chances look too low to mention at this time. Comfortable temps near normal over this period. Rest of the forecast...High pressure is then projected to stick around for Tuesday into much of Wednesday. The flow will be shifting more to the southwest aloft during this time, so think precip chances will gradually ramp up late Wednesday into Thursday. Temps and humidity levels will also be slowly increasing during this time. && .AVIATION...for 06Z TAF Issuance Issued at 1046 PM CDT Fri Aug 11 2017 Clouds should exit northeast Wisconsin by around 12z Saturday. Some MVFR ceilings are possible east of an Iron Mountain to Green Bay line, but it will mostly be VFR. Good flying weather is expected Saturday through Sunday except for areas of ground fog Sunday morning between 09z and 12z. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....TDH LONG TERM......MPC AVIATION.......RDM
Area Forecast Discussion...UPDATED
National Weather Service Huntsville AL
816 PM CDT Fri Aug 11 2017 .NEAR TERM...(Tonight) Issued at 816 PM CDT Fri Aug 11 2017 Loosely organized MCS was moving southeast through southern TN and north central AL. Radar trends indicate that the intensity of the rainfall has diminished somewhat. We have had reports of 1.5-2.75 inches of rain in and around HSV in the past couple of hours, with 2.60 at UAH/MIPs adjacent to here at the NWS office. The HRRR trends indicate a similar trend of further weakening/dissipating over the next couple of hours as the system moves southeast. Have updated PoP/Wx grids to account for this trend. Will leave a 20-30 PoP after 06Z given the very moist and unstable airmass we have in place. Otherwise, low clouds will once again redevelop and plague the area late tonight into Saturday morning. .SHORT TERM...(Saturday through Sunday) Issued at 230 PM CDT Fri Aug 11 2017 Overall the model chaos continues in the short term. The guidance all agrees that a series of shortwaves/embedded vortices will round the base of the longwave trough across the Mid Mississippi Valley and across the Tennessee Valley sometime in the Saturday-Sunday time frame. Unfortunately, in this type of pattern the timing is all over the place. The 12z ECMWF swings a rather notable s/w across the area on Sunday while the NAM/GFS are subsident on Sunday. Conversely the GFS/NAM have a much stronger shortwave on Saturday while that feature is not as well depicted in the ECMWF. For now, will have slightly higher pops overall for Saturday (where PWATs will be similar to the past 24 hours) but generally mid range both days. Given high PWATs and saturated soils, the largest concern will continue to be heavy rainfall/flash flooding. Temperatures will also continue to run 5-7 degrees below normal through the weekend. .LONG TERM...(Sunday night through Thursday) Issued at 230 PM CDT Fri Aug 11 2017 The extended seems like a rinse and repeat with unsettled weather lingering through the week and nearly steady temps. An upper-level trough will dig out of the Northern Plains on Monday and as a sfc low lifts through the OH Valley, a front will stall near the TN Valley. Heavy rainfall and gusty winds will be the main threats with these storms as once again, moisture will not be a problem with PWATS ~2 inches and a lack of shear. Rain chances will decrease as we head into the middle of the week as Great Lakes sfc high pressure builds a little bit into the region. As for temps, look for daytime highs in the mid/upper 80s with overnight lows around 70. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 558 PM CDT Fri Aug 11 2017 Clusters of thunderstorms and showers will occur this evening, mainly before 03Z. Visibility may be reduced to 2sm or less in heavy rainfall with ceilings at or below 025agl. Given the very moist airmass, low clouds are again expected to develop late tonight into Saturday morning. Ceilings of 010-015agl are likely, and could drop to around 006agl in some areas. The ceilings should lift slowly Saturday morning, with VFR conditions returning by around 18Z with scattered cumulus of around 040agl. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...17 SHORT TERM...15 LONG TERM...JMS AVIATION...17 For more information please visit our website at
Area Forecast Discussion
National Weather Service Wichita KS
608 PM CDT Fri Aug 11 2017 .SHORT TERM...(This evening through Monday night) Issued at 245 PM CDT Fri Aug 11 2017 Cold front that pushed through KS late last night is currently situated down along the Red River with a slightly cooler and drier airmass spilling into the region. Water vapor imagery shows an impulse embedded in the moonsonal flow over the desert sw and lifting to the northeast. Made some fairly significant changes to precip chances for tonight and Sat to basically decrease chances. Best storm chances tonight now look to remain southwest of the forecast area where better 850-700mb moisture transport will be situated. Models also in good agreement that shower/storm chances associated with the moonsonal impulse, will be very slow to work back to the northeast for Sat, keeping the bulk of the activity down in OK. So feel that most of the area will remain dry Sat with the exception of southwest portions of the forecast area. Will hold onto some storm chances Sat night but confidence is much higher for locations across far southern KS and especially OK. For Sun there is good model agreement that shortwave energy will be tracking across the northern Mississippi Valley and approaching the western Great Lakes region. Meanwhile, the Plains will remain in unseasonably strong west/nw flow with a series of weak perturbations sliding through. Will maintain some small precip chances for Sun into Sun night but confidence is very low at this time and would not be surprised if precip chances are removed for Sun with later forecasts. The GFS is much more aggressive than the ECMWF, and somewhat the NAM, in tracking upper energy out of the Rockies and across KS Mon into Mon evening. Meanwhile, the ECMWF and NAM keep the bulk of the precip south of the forecast area. Once again, will hold onto storm chances Mon-Mon night with low confidence in this occurring. Confidence is much higher with regards to temps as they will remain well below seasonal averages as they top out in the 80s. .LONG TERM...(Tuesday through Friday) Issued at 245 PM CDT Fri Aug 11 2017 Pattern looks to remain unsettled through at least mid week before upper ridging starts to strengthen over the southern Plains which will push the stronger westerlies north. So at this time feel the better precip chances will be through Wed night, before we enter a less progressive pattern. Should also see a return to more seasonal temps by the end of the work week as we get highs back to the low 90s. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) Issued at 610 PM CDT Fri Aug 11 2017 High pressure ridging into the area will continue this evening. Overnight, several of the latest runs of the HRRR have produced an MCS moving into the region overnight. Arrival will be at GBD by 10z and areas east of there (HUT/ICT) by 12z. Introduced a VCTS for GBD but will hold off until more confident for TAFs east of there. What happens with this convection will drive much of Saturday. Any precipitation will be south of I-7o in eastern KS. && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 66 80 66 82 / 10 20 30 20 Hutchinson 65 79 64 82 / 10 20 30 20 Newton 64 78 64 81 / 10 10 20 20 ElDorado 65 79 64 81 / 10 10 20 30 Winfield-KWLD 67 80 66 82 / 10 20 30 20 Russell 62 81 64 83 / 10 30 30 20 Great Bend 63 80 64 83 / 20 40 30 20 Salina 63 82 64 84 / 10 10 20 30 McPherson 64 80 63 82 / 10 20 20 30 Coffeyville 64 82 67 80 / 10 10 40 60 Chanute 63 81 65 80 / 10 10 20 40 Iola 63 81 65 80 / 10 10 20 40 Parsons-KPPF 63 82 67 80 / 10 10 30 50 && .ICT WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...RBL LONG TERM...RBL AVIATION...CWH
Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
1016 PM CDT Fri Aug 11 2017 .UPDATE... A batch of scattered showers and t-storms have developed along a confluent zone across the central and eastern South Plains in conjunction with a larger-scale outflow boundary moving southwest from the Rolling Plains onto the Caprock. This activity will continue to move northeast over the next few hours, although we can`t rule out some additional isolated development along the outflow boundary. Of greater concern is the t-storm activity in New Mexico associated with a mid-level vortmax. The latest satellite and radar imagery shows one MCS taking shape across northeast NM leaning into the western Panhandles, with indications of another developing in the vicinity of the Sacramento Mtns in south- central NM. The latest high-res guidance including the HRRR and TTU-WRF along with the 00 UTC NAM suggest that this activity will progress across much of our forecast area in the early morning hours Saturday - although there is quite a bit of difference in the details. We have the highest confidence of storms affecting our western and northern counties, but the picture becomes more murky to the south and east as the LLJ will be weakening by the time storms approach that area - likely leading to their weakening as well. Some pockets of heavy rainfall are certainly possible across the southwest Texas Panhandle and western South Plains. PoPs have this scenario well represented and we`ve made only a few minor adjustments. && .PREV DISCUSSION... /issued 649 PM CDT Fri Aug 11 2017/ AVIATION... Isolated convection has recently been attempting to develop between KPVW and KCDS along a residual boundary, but this activity will likely fade out later this evening without impacting either terminal. Of greater concern is more widespread convection currently over central New Mexico. There is a good signal that a large batch of showers and thunderstorms will move eastward out of New Mexico late tonight and across parts or much of the South Plains region Saturday morning as it gradually decays. Given this we have decided to include PROB30 remarks at all three terminals valid Saturday morning at KLBB and KPVW (for thunder) and at KCDS (for showers) from late morning into the early afternoon. Increasing moisture may also support the development of sub-VFR ceilings at times Saturday morning, while light winds prevail outside of any thunderstorm influences. PREV DISCUSSION... /issued 402 PM CDT Fri Aug 11 2017/ DISCUSSION... The biggest change with this forecast iteration was to boost PoPs considerably late tonight through Sat morning over much of the Caprock. Rationale for this is tied to a well defined mid-level vorticity maximum exiting southeast AZ. Water vapor imagery shows an axis of deeper ascent ahead of this impulse - the leading edge of which should reach our western zones after midnight. Until then, the main focus for rain chances appears to favor the southern Panhandle near a stationary front partially reinforced from overnight storms. Visible satellite shows agitated Cu near Tulia just after 3 PM which could easily manifest into some storms with max heating/convective temps just around the corner. Continued light upslope winds should also aid in low level ascent for at least spotty storms despite prevalent upper ridging. As the aforementioned impulse exits NM on Saturday, the upper ridge will completely erode as 20-40 meters worth of mid-level height falls unfold. Such forcing this time of year is sizable enough to sustain the early A.M. precip through most/all of the morning. Pending the behavior of the lingering frontal boundary, models favor the brunt of precip to affect our N-NW zones. PWATs of 1.5 inches on the Caprock would easily breed some heavy rainfall at times, but sufficient W-SW flow aloft should keep precip progressive enough to stave off a larger flooding threat. This more definitive round of morning precip and thicker clouds could deal a blow to PoP chances later in the day, particularly behind the departing impulse. Opted to trim PoPs a bit lower in the afternoon compared to the morning to reflect the departing wave and generally more stable conditions. High temps were also scaled a bit lower for Saturday`s thicker clouds and rain chances. On Sunday, steady height rises initially are progged to be replaced by another respectable trough in westerly flow. Favorable SE low level flow ahead of this wave will maintain good PWATs of 1.5 to 2 inches from W-E across the CWA, so once forcing arrives later in the day (along with a stalling cold front) we should see our next good opportunity for rain and perhaps even some flooding. Thereafter, westerly winds aloft will back more SW as mean troughing occupies the western CONUS. Such a pattern looks favorable for directing a monsoonal plume over West Texas, but subtle day-to-day variations could easily hinder the otherwise generous Superblend PoPs through late week. Opted to lower these Superblend values a bit for obvious uncertainty, but max and min temps look to fall close to climo most days. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 23/33
Area Forecast Discussion
National Weather Service Melbourne FL
852 PM EDT Fri Aug 11 2017 .DISCUSSION... Currently/Tonight...The weak surface low continues to pull slowly to the north of the area, which is allowing the surface ridge to build across the southern peninsula. Sandwiched in between is a slug of very high precipitable water around 2.2 inches. Diurnally driven convection is diminishing but the high moisture and a few lingering boundaries may continue to generate isolated-scattered showers across the north. We have chance POPs there until midnight which still seems prudent. A large area of stratiform rain across the south third will gradually diminish through late evening. Thereafter, the HRRR and local WRF don`t show any further precip chances. With all the moisture in the atmosphere, considerable cloudiness should linger through the night. Only minor changes have been made to the previous forecast. && .AVIATION...Lingering stratiform rain across the southern terminals will diminish through late evening. Low levels will be very moist but considerable debris cloudiness should preclude any significant periods of low stratus. How long the cloudiness persists into Sat will determine time of convective onset. Have gone with 17-18z for now, but could be sooner in some spots if clouds break up quicker. && .MARINE... Tonight-Saturday....Weak surface low lifting north of the waters and ridge building in across the south will gradually ease the pressure gradient tonight and by Sat we should have a southwest wind flow 10 knots or less across the waters. This will result in rather benign seas on Sat. Some strong storms should push off the coast in the afternoon though. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ Forecasts...Lascody Radar/Impact Wx...Sedlock/Smith
Area Forecast Discussion
National Weather Service San Angelo TX
614 PM CDT Fri Aug 11 2017 .AVIATION... /00Z TAFS/ VFR conditions will continue across West Central Texas terminals through Saturday morning. A few of the high res models (Specifically the HRRR) are showing a chance of showers and storms moving across the area and its terminals n Saturday afternoon. This not really supported by the other models or the current forecast and will not include a mention of these storms at this point. Have plenty of time to watch and update the late forecasts if the trend of the HRRR continues. Otherwise, light winds will prevail. && .PREV DISCUSSION... /issued 345 PM CDT Fri Aug 11 2017/ SHORT TERM... (Today and Saturday) An upper level high centered over central Texas will lead to another warm and mainly dry night across our area. An isolated shower or thunderstorm, however, cannot be ruled across the northern Big Country mainly north of I-20. Otherwise, expect mostly clear skies with lows in the lower to mid 70s. On Saturday, the upper high will remain centered across the southern half of the CWA. Meanwhile, a frontal boundary draped across the Red River will sag slowly southward and lie near the northern Big Country by the late afternoon. Hi-res model guidance indicates scattered thunderstorms developing mainly north of the I-20 corridor along the boundary. The Storm Prediction Center does have Haskell and Throckmorton counties outlined in a slight risk for severe thunderstorms with the primary threat being damaging downburst winds. Otherwise, expect another hot afternoon across the CWA with highs in the mid to upper 90s. LONG TERM... (Saturday night through Friday) A cold front is forecast to stall across North Texas Saturday night, with shower and thunderstorms development across much of North Texas/Oklahoma. Some of this activity may move into portions of the Big Country, although the bulk of the convection will remain north of the area. In addition, isolated to scattered showers and thunderstorms are forecast to develop across West Texas during the early evening hours. Some of this activity may drift into western portions of the forecast area, before dissipating by mid to late evening. A few of these storms may become strong to severe, with hail, strong gusty winds, and locally heavy rainfall being the main concerns. Sunday into the first part of next week, scattered showers and thunderstorms will once again be possible across North Texas in association with the remnant cold front, with isolated to scattered showers and thunderstorms possible across portions of West Texas due to a continued surface trough. Some of this activity may approach our northern and western counties during the late afternoon/evening hours. The influence of an upper level ridge centered across South Texas will preclude this activity from making it too far south and east into the forecast area. Highs through this period will remain in the mid to upper 90s, although a few locations may approach the century mark. Overnight lows will mainly be in the mid 70s. Upper level ridging will build back into the area for the middle to latter part of the week, resulting in hot and dry conditions && .PRELIMINARY POINT TEMPS/POPS... Abilene 75 98 75 98 / 10 10 30 20 San Angelo 74 100 75 100 / 5 5 10 10 Junction 73 98 74 99 / 5 5 5 5 Brownwood 74 99 75 99 / 5 10 10 20 Sweetwater 74 96 74 96 / 10 20 30 30 Ozona 73 96 73 98 / 5 10 5 10 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ 07
Area Forecast Discussion
National Weather Service Tulsa OK
853 PM CDT Fri Aug 11 2017 ...UPDATE... .DISCUSSION... Forecast is largely on track for tonight, with only a few tweaks to cloud cover required. Very isolated diurnal showers/storms across far eastern Oklahoma and western Arkansas have dissipated with sunset, and most areas should remain dry through the night. The HRRR continues to show some development toward sunrise across portions of southeast Oklahoma, in response to increasing low level warm advection. The existing slight chance POPs should cover this potential, as the better chances and greater coverage should hold off until tomorrow. Updated products already out. && .PREV DISCUSSION... /Issued 642 PM CDT Fri Aug 11 2017/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. Few to scattered mid/high clouds should remain common across Eastern Oklahoma and Northwest Arkansas overnight. Parts of far Northwest Arkansas may develop some MVFR cig/vis early Saturday morning...though conditions should lift back to VFR mid to late morning Saturday. During the day Saturday...increasing mid and high clouds are forecast to spread across the CWA with east to northeasterly winds. Some precip chances could become possible during the afternoon hours and have added a Prob30 group to MLC as Southeast Oklahoma looks to have the greater potential. PREV DISCUSSION... /Issued 321 PM CDT Fri Aug 11 2017/ DISCUSSION... Overnight convection has essentially worked over the atmosphere today and also shoved the synoptic boundary well south of the forecast area. Thus...chances of any convective redevelopment the remainder of the day will be slim. Models continue to struggle with the placement of the heaviest rainfall through the weekend/early next week...although current indications point to the Red River area as the favored area beginning late Saturday. The aforementioned frontal boundary is expected to lift a bit north tomorrow...with increasing convection north of the boundary by the afternoon as a well-defined mid-level wave traverses the southern Plains. This activity should continue to organize and peel east-southeast...impacting areas mainly south of I-40 during the evening and overnight hours. Some severe weather will be possible along with locally heavy rainfall given forecast PWATs near 2 inches. Have held off on any flood headlines at this time as the event is still a good 24-30 hours away...although evening/overnight crew will need to revisit. The GFS and ECMWF diverge significantly with their respective QPF later Sunday into early Monday...with the GFS much farther north with the axis of heavy rain. Will lean toward a farther south solution at this time (essentially blending the two solutions)...which places additional heavy rainfall along the I-40 corridor. The upper pattern is expected to become a bit more southwesterly going into mid-week...which should eventually lift the synoptic boundary north of the area along with decreasing rain chances. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ SHORT TERM...22
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
531 PM MDT Fri Aug 11 2017 .DISCUSSION...(This Evening Through Friday) Issued at 135 PM MDT Fri Aug 11 2017 Upper trough continues across the eastern half of the CONUS...while ridging remains over the west coast. A series of shortwaves are pushing southeast across the northern High Plains...all the way into Canada. This will allow for active weather over the next couple days. Storms have quickly developed over the last hour across northeast WY and the Black Hills area. Models continue to show relatively weak CAPE of 800-1200 J/KG and decent shear. A few storms could end up severe...but generally most storms are expected to be weak to moderately strong with small hail and gusty winds. HRRR shows the developing line of storms moving eastward over the next 6 hours crossing the Black Hills area...then pushing into central SD through the evening. Surface high pressure across the MS Valley will keep south/east flow across the area Saturday as a shortwave crosses the region. A surface trough will straddle the CWA through the day with the best instability across southwest to south central SD. MLCAPE of 1500- 2500 J/KG is expected with decent...but not great...shear. It will enough for some storms to become strong to severe Monday afternoon and evening. Highs will be in the 70s to low 80s. Upper wave will push east of the area Sunday with drier weather expected. The ridge axis will cross the northern plains Monday morning with southwest flow developing by Monday evening. Another round of storms are possible Monday evening with some severe storms possible as a strong upper wave crosses the region along with a surface trough. Daily chances for storms are expected next week as a broad upper trough slowly crosses the region. && .AVIATION...(For the 00Z TAFS Through 00Z Saturday Evening) Issued At 526 PM MDT Fri Aug 11 2017 A broken line of thunderstorms will continue to shift east across the southeast third this evening. Gusts to 45 knots will be possible with these storms. Other isolated TS are possible across NW SD this evening, with large hail and gusts over 45 knots possible there. Local IFR conditions are possible with the thunderstorms. There may be some patchy fog in the early morning adjacent to the Hills. Otherwise, TS will develop once again across western SD, esp scentral SD Sat afternoon. A few strong to severe storms will be possible as well as local MVFR/IFR conds. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION...13 AVIATION...JC