Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/09/18

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
821 PM CDT Fri Jun 8 2018 .DISCUSSION... Think we may be in for a repeat performance of sorts of last night. An outflow boundary is slowly moving west and will meet up with convection as it moves into the NW Panhandles. This may invigorate this line of storms briefly, but SFC analysis again shows an area of SFC divergence east of the boundary that should weaken and greatly limit coverage of storms that make it much out of the western column of COs. The HRRR basically shows this is exactly what happens despite the favorable H7 theta-e ridge across the WRN half. Have updated to raise POPs in the NW but decreased or eliminated POPs in the east. Can`t totally rule out a storm making it to AMA or outflow causing a storm to develop near AMA similar to last night, but it is not looking very promising. && .AVIATION... Main concern for the period continues to be potential for storms to impact the TAF sites in the evening/overnight periods tonight and again Saturday. DHT is most likely location to be impacted, and have included tstms in TAF their tonight. Chances are not high enough for mention any other location attm. && .PREV DISCUSSION... /Issued 359 PM CDT Fri Jun 8 2018/ SHORT TERM... Outflow from this morning`s thunderstorm activity with increasing pressure gradients resulting from it has kept winds elevated through the morning and early afternoon hours. Surface analysis still shows the dryline currently set up in eastern New Mexico with dewpoints in the 50s and 60s across the entire region. This, along with an upper level shortwave trof is riding over the ridge this afternoon, will serve as a focal point for thunderstorm development. More isolated thunderstorm development is possible along the westward advancing outflow boundary now just east of Amarillo to near Perryton. Timeframe for any convection favors the late afternoon and evening hours, with most activity expected to be in the western Panhandles by around 6 PM CDT and persisting through about midnight. A few storms are already developing in the Raton Mesa vicinity as of 2000z. Storm motions will be a bit slow, as morning sounding indicates steering flow will be roughly 5 to 15 kts from the west to southwest. Given this slow storm motion, thunderstorm activity will have difficulty making it into the eastern Panhandles. Any storms that develop will be working with a dry surface boundary layer and, if the sounding is modified for current conditions, presents with DCAPE values that exceed 1600 J/kg. As a result, hazards with any thunderstorms will be wind for short-lived storms and those that cluster into linear modes, and hail should any storm maintain a pronounced updraft for a prolonged period of time. Storms could be strong to severe given the hazards analyzed. Updates were made to PoP grids to refocus best chances out west, wind grids due to increased pressure gradients, and dewpoint temperatures to account for present trends. Bieda/Ward LONG TERM... Broad upper level trough currently advancing towards the Pac NW coast is progged to stall over the Great Basin for the next few days. The mid level ridge is currently centered over southeast New Mexico and is not expected to change much through Saturday. This will keep the Panhandles in weak zonal to northwest flow aloft. For Saturday, temperatures should be similar to Friday, if not a few degrees cooler. Convection will be possible in the western zones in response to a subtle perturbation riding around the ridge in the region of the surface trough. While convective inhibition does not look to be a major issue, storms will be fighting some dry air entrainment in the H5 to H3 region based on latest model soundings. Otherwise, a few storms could become strong with high- based MLCAPE around 1000 J/kg and steep low level lapse rates. Shear does not look impressive given weak mid- level winds, so large hail does not look likely. Downdraft winds would be the the main possibility with single cell to perhaps multicell modes. Deterministic guidance slowly advances the Great Basin trough eastward as it takes on a negative tilt Sunday. While the main trough stays well north and northwest of the Panhandles, there is indication of a shortwave ahead and south of the trough that crosses the Panhandles. The timing of this feature will largely determine when and who might see some thunderstorm development. It does look like a more defined dryline tries to take shape as lee cyclogenesis begins in eastern CO Sunday afternoon. The dryline would be the main area of concern for convective initiation with around 1000 to 1500 high-based MLCAPE and weak shear given overall weak kinematic field. There some veering in the lowest 500mb which may lend to some organization at times. Thus, storms should be of pulse nature to perhaps some multicell clusters with wind and hail being the main threat. The aforementioned surface low ejects east into KS/NE with trailing cold front on Sunday night into Monday. There are differences on how far the front will advance before stalling, so Monday will be tricky on both temperatures and pops. For now confined pops to the southeast zones where better moisture is expected and kept temperatures coolest in the northern zones. The ridge starts to re-center over west Texas as zonal flow dominates the northern plains. Temperatures are expected to surge back up into the upper 90s to near 100 Tuesday into the middle of next week. Differences in the guidance abound especially beyond Wednesday. The overall trend, however, is hot and mostly dry. Ward && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$ 88/88
Area Forecast Discussion
National Weather Service Bismarck ND
940 PM CDT Fri Jun 8 2018 .UPDATE... Issued at 928 PM CDT Fri Jun 8 2018 The main challenge for the remainder of the night is the potential for additional convection across the southwest and far south central. The 01 UTC HRRR, 00 UTC ESRL Experimental HRRR and Hi-Res ARW, and the 18 UTC NAM/GFS all signal the potential for isolated elevated cells developing between 04-09 UTC. The forcing mechanism is the main question, especially with the lack of a low level jet. However, a few weak mid level impulses will propagate through the area overnight, along with possible outflows from convection across southeast Montana and northwest South Dakota. With ample instability and shear an isolated storm or two are possible, with a marginal risk for severe hail. However, the threat is highly conditional and confidence is low. UPDATE Issued at 623 PM CDT Fri Jun 8 2018 Little change with this update outside of observed trends through 23 UTC. Other than an isolated rain shower or thunderstorm across the far southwest through sunset associated with the agitated cumulus field, which has shown a few attempts at convective initiation the past hour or so, maintained a dry forecast for the remainder of western and central North Dakota this evening and tonight. && .SHORT TERM...(This evening through Saturday) Issued at 300 PM CDT Fri Jun 8 2018 A short wave was triggering scattered thunderstorms over eastern North Dakota late this afternoon and they were east of the Bismarck forecast Area and moving northeast. Another weak wave moves in overnight tonight and although an isolated shower or storm is possible it is not likely. To blanket large areas with a 20 pop would be a dis-service. Mostly sunny on Saturday and very warm ahead of Sunday`s cold front with highs in the 80s. .LONG TERM...(Saturday night through Friday) Issued at 300 PM CDT Fri Jun 8 2018 Ahead of Sunday`s cold front the thermal ridge, significant with h8 temperatures of +26 degrees C, pokes over the forecast area. This will result in mild overnight lows Saturday night and another very warm day Sunday. Later shifts will need to monitor for forecast highs Sunday possibly not being high enough. With that sharp cold front, and increasing moisture ahead of it, instability will be significant, and with slow moving storms heavy rain along with the typical risks of large hail and damaging winds should will expected. Much cooler then for early next week and much more stable. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 928 PM CDT Fri Jun 8 2018 An isolated thunderstorm is possible across far southwest and far south central North Dakota tonight. Otherwise, dry and VFR conditions are forecast across western and central North Dakota for the 00 UTC TAF cycle. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...PA SHORT TERM...JPM LONG TERM...JPM AVIATION...PA
Area Forecast Discussion
National Weather Service Columbia SC
706 PM EDT Fri Jun 8 2018 .SYNOPSIS... An increasing onshore flow over the weekend and into the beginning of next week will increase the chance of mainly afternoon and evening thunderstorms. Temperatures will be near or slightly above normal. && .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... Expect isolated shower and thunderstorm coverage this evening with dry air aloft and weak surface forcing. The HRRR continues to show little in the way of coverage increasing confidence. The threat of severe weather is low with deep convection struggling to develop through the dry mid-levels. Any lingering showers and thunderstorms will diminish by late this evening with loss of heating. Lows tonight will be around 70 degrees. && .SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Upper trough over the Pacific Northwest will advance toward the Rockies over the weekend with an upper ridge over the southern Plains and upper weakness over Florida and Southeast coast. Moisture will be deeper on Saturday and Sunday than on Friday with PWAT values up to 1.8 inches. Isolated to scattered diurnal convection is expected both days with the highest chance east. The severe threat appears low given weak to moderate instability and weak shear. Temperatures will be near to slightly above normal over the weekend, with highs in the lower 90s and overnight lows around 70. && .LONG TERM /MONDAY THROUGH FRIDAY/... A backdoor cold front will move into the northern portion of the forecast area on Monday and gradually sink southward into Tuesday bringing increased chances of showers and storms. Lingering moisture will remain across the region through the end of the work week with mainly scattered diurnal convection expected each day. Models show shortwave energy in the area on Wednesday which should enhance convective activity. High temperatures are forecast in the upper 80s to lower 90s through the period with overnight lows around 70. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Expect mainly VFR conditions during the 24-hour TAF period. There will be a weak pressure gradient in the forecast area through tonight with ridging northeast of the area and weak troughing near the coast. Deepest moisture should remain east and south of the area ahead of the trough and low near the Southeast Coast and northeast Gulf of Mexico. Shower and thunderstorm coverage has been isolated. Thunderstorms not expected to impact terminals this evening. So scattered cumulus diminishing during the evening. Nocturnal cooling and low-level moisture may lead to fog or stratus mainly in the southeast Midlands near OGB and AGS. The latest HRRR model and Lamp suggest a higher stratus threat near OGB, but confidence remains low for IFR conditions. Will continue MVFR conditions 09z-12z at those locations. Scattered cumulus again tomorrow with little change in air mass. With weak instability and limited moisture showers and thunderstorms should remain isolated or widely scattered with focus in the east associated with sea breeze. EXTENDED AVIATION OUTLOOK...There may be restrictions in stratus and fog during the early morning hours and also in mainly afternoon and evening thunderstorms. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service State College PA
1028 PM EDT Fri Jun 8 2018 .SYNOPSIS... A weak cold front that moved across the state today will stall out to the south of Pennsylvania heading into this weekend. After an unsettled weekend, mainly dry conditions will return for early next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Weak stationary boundary lies along and just north of the I80 corridor in central PA late this evening...with dewpoints in the lower 60s to its south. Dewpoints to the north of it are in the low to mid 50s. Showers made a run at my southeast counties at mid evening but died as they tried to cross into Somerset County. A stray shower or thunderstorm still cannot be ruled out there overnight given the nearby moisture axis and the aforementioned front which is expected to sag southward through 12z Sat...and the HRRR still shows shows very isolated activity so POPs are very minimal. If skies clear out sufficiently, patchy fog could become an issue. It will be milder than normal ranging from around 50 along the NY border to a couple of degrees either side of 60 over southern areas. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... The warm front will be stalled along or just south of the MD border for Saturday. It`s a weak front and the models cook up some modest instability north of it up into about the southern 1/2 of the CWA. The main problem will be the extent of convective initiation upstream that will/might slide SE through this unstable air during the peak heating. There is very little if any agreement between the 12Z models on where the best chance of rain will be. Both the SREF and GEFS show the PWATs recovering to a bit above normal over about the southern 1/2 of my CWA by the afternoon which is where I painted my highest POPs. But it`s hard to find a coherent mid/upper level trigger to increase my confidence on timing or placement. Highs Saturday will vary from the low to mid 70s northern tier to around 80 degrees in the lower Susq valley. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Pattern overview: High amplitude/blocky trough/ridge/trough configuration across the northern tier U.S. during the first part of the period is forecast to transition toward a more zonal/progressive flow by the middle to second half of next week, as the main belt of westerlies undercut an anomalously strong/closed northern Canada upper high. A wavy surface frontal boundary extending from the Mid Atlantic back into the Upper Midwest will remain a focus for repeated showers/storms this weekend into early next week. A cold front will enhance rainfall probs around the middle of next week. Model guidance/Predictability Assessment: Models are having their usual difficulty with details (timing/location) but seem to be in somewhat of a consensus in tracking one or more rounds of showers/T-storms across southwest/south central PA Saturday night-Monday. Global models tend to be too far north with this type of activity vs. the hires CAMs. There are timing differences with the frontal passage next Wednesday with GFS faster than the ECMWF. Weather Highlights/Hazards/Potential Impacts: Isolated/marginal risk for strong to severe storms with potential rounds of heavy rainfall appear be focused across south-central PA Sat. night into Mon. Daytime highs will be cooler than avg Sun-Mon but should moderate through the end of next week. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Widespread VFR conditions and a light breeze will continue through the remainder of the evening hours. A frontal boundary extending west to east across the state will be the focus isolated showers or thunderstorms into late this evening. Convection and associated sig reductions should be confined to southwest corner of the central PA airspace, south of KJST. However, some lower VFR cigs could push into KJST through 03Z. Other than some patchy valley fog overnight, no sig weather is expected into Saturday morning. .Outlook... Sat-Mon...Scattered showers/thunderstorms, mainly over southern portions of the flying area, with locally reduced conditions. Tue...No Sig Wx. Wed...Scattered showers and thunderstorms with localized reduced conditions. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...DeVoir/La Corte SHORT TERM...La Corte LONG TERM...Steinbugl AVIATION...La Corte/Gartner
Area Forecast Discussion
National Weather Service Cheyenne WY
851 PM MDT Fri Jun 8 2018 .UPDATE... Issued at 850 PM MDT Fri Jun 8 2018 Upon coordination with the Storm Prediction Center, we have cancelled the Severe Thunderstorm Watch for our Wyoming and Nebraska Counties that were affected. Updated gridded forecasts have been sent. UPDATE Issued at 304 PM MDT Fri Jun 8 2018 THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH 163 IN EFFECT UNTIL 10 PM MDT THIS EVENING FOR THE FOLLOWING AREAS IN NEBRASKA THIS WATCH INCLUDES 3 COUNTIES IN WESTERN NEBRASKA BOX BUTTE DAWES SIOUX IN WYOMING THIS WATCH INCLUDES 2 COUNTIES IN EAST CENTRAL WYOMING NIOBRARA IN SOUTHEAST WYOMING GOSHEN THIS INCLUDES THE CITIES OF AGATE, ALLIANCE, CHADRON, CHADRON ST PARK, HARRISON, LUSK, REDBIRD, AND TORRINGTON. .Mesoscale Update... Storms are developing along the Laramie Range and in a maturing CU field across the Nebraska Panhandle. LAPS and observations showed mid to low 60s dewpoints across Nebraska and mid 50s across southeast Wyoming. This moisture under steep mid level lapse rates was generating 5500 j/kg of SBCAPE. Shear is on the weaker side with 0-6km Bulk shear at or about 30 kts. This should favor a mixed multicell/weak supercell mode with the threat for large hail, damaging winds, and an isolated tornado. The tornado threat in particular appears fairly marginal with about 100 m2/s2 0-3km helicity. Storms will mature rapidly in the large CAPE environment and will likely congeal into a more solid line later this evening. This line/ MCS would have the potential for a damaging wind threat as it translates east southeast. && .SHORT TERM...(This evening through Sunday night) Issued at 235 PM MDT Fri Jun 8 2018 A few forecast concerns in the short term forecast today. First off, severe thunderstorm potential today, then winds and fire weather concerns this weekend. Currently...Surface low pressure system being analyzed on analysis near the northeast corner of Niobrara County this afternoon. A Dryline being analyzed near the Wyoming/Nebraska border extending south along the Front Range. IR Satellite imagery showing supercells developing across northeast Wyoming into western South Dakota. SPC Mesoanalysis page showing surface based CAPE around 5500 J/KG over most of the Panhandle with around 3000 J/KG up to the I-25 Corridor in southeast Wyoming. Very humid in the Panhandle with 2PM dewpoints in the mid 60s at Chadron, 60 at Sidney and 68 at Alliance. Storms are beginning to form on radar along the Laramie Range, especially up near Douglas. Latest HRRR showing convection becoming severe here shortly across northern Goshen County and then moving northeast into the richer CAPE/instability. Likely intensifying as they track across the northern Panhandle. Bowing structure/squall line signature being seen on simulated radar across the northern Panhandle after 00Z, so strong winds and hail look to be the primary hazards. Looks like convection ends/moves east by 03/04Z this evening. For Saturday, southwest winds are going to be on the increase across Carbon County. GFS 700mb winds increase to 30-35kts. Forecast soundings show mixing up to 525mbs, so its going to be windy across Carbon County. Afternoon humidity down into the single digits with these winds. Fuels were just turned over to Yes for 305, 307 and 309, so a Red Flag Warning was warranted for 305 and 307. Even stronger winds Sunday as a dry cold front moves across the area. GFS 700mb winds up to 50kts and soundings showing winds mixing at 500mbs of 50 to 55kts. So we could be flirting with high wind criteria along with critical fire weather conditions. Issued a Fire Weather Watch for 305, 307 and 309. .LONG TERM...(Monday through Friday) Issued at 235 PM MDT Fri Jun 8 2018 Dry, breezy and cooler Monday as the upper trough axis swings well east of the area and surface high pressure builds into the region. Dry conditions should then continue through Weds as the CWA resides under westerly upper flow with temperatures warming. A passing weak impulse may set off a bit of convection Thursday as moisture begins to increase. Friday should see the approach of the next upper shortwave from the northwest with a little better chance for convection late in the day. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 547 PM MDT Fri Jun 8 2018 Wyoming TAFS...VFR at Rawlins with wind gusts to 25 knots through 03Z and to 32 knots after 15Z Saturday. VFR at Laramie with isolated thunderstorms in the vicinity through 02Z and wind gusts to 23 knots through 02Z and to 23 knots after 15Z. VFR at Cheyenne with isolated thunderstorms through 02Z producing wind gusts to 40 knots. Wind gusts to 20 knots after 15Z Saturday. Nebraska TAFS...VFR at Chadron, Alliance and Scottsbluff with isolated thunderstorms through 03Z producing wind gusts to 45 knots along with brief MVFR. Wind gusts to 26 knots after 15Z Saturday. VFR at Sidney with thunderstorms in the vicinity through 03Z and wind gusts to 20 knots through 03Z and to 24 knots after 15Z Saturday. && .FIRE WEATHER... Issued at 235 PM MDT Fri Jun 8 2018 Fuels have been reported ready in FWZs 305, 307 and 309 just today. Expect a windy period for Saturday through Monday, initially beginning across Carbon County Saturday. These winds will become more widespread Sunday across much of southeast Wyoming and Nebraska Panhandle as a dry cold front approaches. The front looks to move through the area Sunday evening with winds shifting from west to northwest. In the meantime, strong winds and very low humidity is expected to create critical fire weather issues for FWZ 305 and 307 Saturday and 305, 307 and 309 Sunday. Red Flag Warnings are in effect for 305 and 307 Saturday, with watches in effect 305, 307 and 309 Sunday. Most other areas in southeast Wyoming and Nebraska Panhandle will see the strong winds and low humidity, especially Sunday. But fuels are still reported not receptive. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Red Flag Warning from 11 AM to 8 PM MDT Saturday for WYZ305-307. Fire Weather Watch from Sunday morning through Sunday evening for WYZ305-307-309. NE...None. && $$ UPDATE...RUBIN SHORT TERM...GCC LONG TERM...RE AVIATION...RUBIN FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Des Moines IA
648 PM CDT Fri Jun 8 2018 .SHORT TERM.../Tonight through Saturday/ Issued at 359 PM CDT Fri Jun 8 2018 Visible imagery and surface observations shows a warm front stretched from Sac City to near Des Moines to Ottumwa with cumulus south of this boundary. A remnant mesoscale convective vortex less obvious in satellite imagery than yesterday is also over northwest Iowa and 19z SPC mesoscale analysis shows a 500mb vorticity max in this area. Additionally, south of this boundary MUCAPE values are 2500 J/kg or higher with little in the way of inhibition, but overall shear is weak with maybe 30 knots of deep layer shear and 25 knots of effective shear. Surface convergence is spotty and weak as well , but there are isolated showers or thunderstorms trying to develop along this boundary. A few storms have pulsed up with warnings for hail the main concern over the last hour or so. Convective allowing models like the HRRR and ESRL HRRR have been unrepresentative of the current atmosphere, but overall thinking is that isolated to perhaps scattered storms will continue through the remainder of the afternoon along this boundary. Hail will continue to be the main concern along with the possibility of strong, gusty winds if storms are unable to maintain separate updrafts and downdrafts. Thunderstorms should exit the area later this evening and attention then turns to the west where a thunderstorms complex should develop aided by a mid-level shortwave trough tonight. These storms are shown to be reaching our western forecast area after midnight tonight and probably closer to sunrise for much of our area. These storms should be trended downward in intensity, but still could pose a threat of heavy rainfall and perhaps a few damaging wind gusts. The atmosphere will have copious amounts of atmospheric moisture with the 08/00z NAEFS showing upper 90th percentile for specific humidity with precipitable water values in the 90th percentile. These percentiles mean precipitable water values (as shown by NAM/GFS) of 1.5 to 2 inches. Warm cloud depths will once again be over 3500 to near 4000 meters. 850-300mb flow is weak again with 10 to maybe 20 knots will spell overall slow storm speed. As for any Flash Flood Watch, thinking is the corridor of heavier rainfall will be south of where the heaviest rain fell Thursday night into this morning. After these storms dissipate or move east of the area, expect another chance of storms late in the afternoon to develop with favored area over the eastern forecast area. These storms, too, will have the possibility of heavy rainfall with high precipitable water values, weak mean flow, and deep warm cloud depths. .LONG TERM.../Saturday night through Friday/ Issued at 359 PM CDT Fri Jun 8 2018 .../Saturday Night through Monday Night/ Confidence: Low to Medium Little change from previous forecast. Active weather pattern remains during the period and with likely meso and synoptically forced interactions dominating the period... the forecast confidence will once again be limited to no more than a 12 to 18 hour period through this portion of the extended. Models continue to offer slightly different solutions and locations of potential MCS through Sunday night/early Monday morning. There is a general consensus of Saturday afternoon MCS activity over north central/central Iowa to dive southeast across southeast/central/east central Iowa during the evening and possibly overnight hours. As mentioned appears that a break will occur later Sunday morning and the remainder of the day as the next upstream wave approaches. This should push the warm front/preferred area of lift north of the region Sunday afternoon. By Monday the stronger upper level system and cold front will quickly move into the area by later in the afternoon...resulting in possible severe storms Monday evening into the overnight hours. Rainfall amounts over the 48 hour period from Saturday night to Monday night will again vary quite a bit...but with the expected warm cloud depths, high PWAT and active weather... conceivably looking at general 1-2 inch totals in areas that see thunderstorms...with excess rainfall of 3 or more inches in training or MCS storms. 12z subjective H850 analysis showed favorable pattern continuing over the Central Plains/Midwest for locally heavy rainfall. Great Lakes high anchored with mid to upper level trough in the lee of the Rockies. H850 low level jet 30 to 45kts southwest into the Panhandle earlier today. Moisture analysis showed 10 to 15 degree dewpoint ribbon moving north toward upper level boundary over MN earlier today. .../Tuesday through Friday/ Confidence: Medium The upper level pattern is still forecast to become more progressive and zonal with slightly cooler H850 temperatures rolling across Iowa from Tuesday through Friday. There is still a signature for another weak wave by late Wednesday with additional warm air advection and thunder potential for Thursday night into Friday as more shortwave energy moves through the flow. Overall highs will be more seasonal...and slightly cooler overall highs and lows overall through Thursday. Highs will trend upward for Thursday and Friday as warmer air moves back toward the region at that time. && .AVIATION.../For the 00Z TAFS through 00Z Saturday evening/ Issued at 648 PM CDT Fri Jun 8 2018 Difficult TAF forecast. Prevailing conditions will be VFR however storms this evening may drift into KFOD, KDSM and KOTM which may produce wind gusts and high end MVFR cigs. Overnight a complex of storms will push in from the west with low confidence as to how far east they will get before dissipating. MVFR conditions likely with the left over stratocu. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Ansorge LONG TERM...REV AVIATION...FAB
National Weather Service Kansas City/Pleasant Hill MO
620 PM CDT Fri Jun 8 2018 .Discussion... Issued at 309 PM CDT FRI JUN 8 2018 As of 19Z, there were several mesoscale features to track that could influence our weather this afternoon and tonight. First, there appears to be an outflow boundary, or some surface convergence zone, running from northeastern MO northwestward into western IA. In western IA there also appears to be an MCV that is tracking to the southeast. Storms have already developed along the outflow boundary/convergence zone in far northeastern MO and southeastern IA. With CU building along the boundary to the northeast, it seems like this will be the most likely area for storms during the afternoon. So for our forecast area, have gone generally dry through the afternoon hours. Later this evening and tonight, as the MCV starts to move into the area, it`s possible storms could form along/ahead of it. The HRRR and the ESRL HRRR both show this, to some extent. The HRRR is much more aggressive building storms southward southern extent of the MCV. The ARW and NMM show something similar but without the update frequency the HRRR/ESRL HRRR, the track of the MCV seems off. This MCV tracking into northern MO is what seems most likely to bring thunderstorms to the forecast area. Have reconfigured low PoPs to account for this possibility. The forecast gets murkier for the weekend. First, it looks like that despite broad and somewhat flat ridging, the thermal ridge shifts to the west into the Plains. So it looks like places to our west will really heat up. This may spread into western portions of the forecast area as well. But in the eastern portions of the forecast area, where there isn`t as warm of air aloft, it looks like thunderstorms could develop Saturday and potentially linger into Sunday. So highs in the middle 90s look likely in our west Saturday and Sunday while highs in the upper 80s look likely in our east given the pattern and the potential for precipitation. For next week, hot and humid conditions will continue Monday with some relief through the middle of the week. For Monday, the thermal ridge will strengthen and spread east ahead of a cold front. So much of the area will see middle 90 degree readings for highs. Then with the front moving through late in the evening, thunderstorms should develop within an extremely unstable air mass. While shear is not all that strong, it`s not nonexistent like it is today and this weekend. So it`s possible there could be strong to potentially severe storms Monday evening and overnight. Cooler temperatures, in a relative sense, are likely Tuesday - Thursday, in the wake of the front. While temperatures in the mid to upper 80s will fee better the middle 90s, it looks like dewpoints will be lower so the air mass will be less humid. && .Aviation...(For the 00Z TAFS through 00Z Saturday Evening) Issued at 617 PM CDT FRI JUN 8 2018 VFR conditions are expected throughout the period, with a slight wind shift from SE to SW overnight. Some isolated thunderstorms are possible over northern Missouri late this evening through the early morning timeframe, mainly effecting the Kirksville airfield. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ Discussion...CDB Aviation...Barham
Area Forecast Discussion
National Weather Service Hastings NE
625 PM CDT Fri Jun 8 2018 .SHORT TERM...(This evening through Sunday) Issued at 354 PM CDT Fri Jun 8 2018 The main forecast concern is the chances for thunderstorms this evening and overnight. An upper level disturbance will move across the Northern Plains and help to induce thunderstorms this evening. Thunderstorms have already fired in the Black Hills and western Wyoming as of this issuance. The high-resolution guidance has continued to indicate the chance for a MCS to develop from this activity in the High Plains and track southeast across Nebraska. The question now though is, how exactly will this convection evolve? The NAM and GFS seem to be struggling some what, but ultimately develop a MCS and track it east/southeast during the overnight aided by low level moisture transport. These guidance keep the bulk of the QPF north of the forecast area, over northern Nebraska. The higher resolution NAMNest shows a squall line developing and tracking south across the heart of Nebraska, including much of the forecast area. The HRRR indicates the potential for convection developing off the High Plains of the Nebraska Panhandle moving east and merging with the squall line from SD and moving across Nebraska. There are a lot of solutions and as mentioned, which will occur? While the details are a bit hairy, the main take away is that there is a decent chance for thunderstorms to impact central and parts of south central Nebraska. The best chance will be along and north of I-80, but cannot rule out the possibility for the remainder of Nebraska. North central Kansas looks like it will stay mostly dry. A marginal and slight risk encompass the forecast area. Think the best chance will be for severe wind vs. hail during the overnight hours. Timing: 10pm-6am. Saturday and Sunday: The main concern for the weekend is the heat. With the upper ridge square overhead, temperatures will soar. Highs will be in the 90s and even breaching the triple digits in north central Kansas. Sunday will be hotter than Saturday across the area. Heat indices will approach 100. There is a small chance for thunderstorms during the day Saturday as it gets warm enough, but upper level support is minimal. The forecast is dry for the whole weekend, but a Marginal Risk is overhead for Saturday. Cannot rule out a convectively induce brief thunderstorm, but for most the chances are better it will remain dry. .LONG TERM...(Monday through Friday) Issued at 354 PM CDT Fri Jun 8 2018 An upper disturbance will be rotating around the upper trough across the northern Rockies/Plains and kick out a cold front across the area for early Monday. With this trough the upper pattern will become more zonal. Temperatures will begin to moderate back to climatic norms in the low 80s. This frontal passage Monday is expected to be mostly dry. There are scattered precipitation chances through the work-week, but the best chance looks to be Tuesday night through Wednesday as a wave moves across the Northern Plains. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday) Issued at 610 PM CDT Fri Jun 8 2018 Expect VFR conditions for most of the forecast period although will need to monitor possible MCS formation to the northwest this evening that could push through the terminals between 05 and 10Z. This could bring vsby down with brief heavy rain. Some gusty outflow winds are also possible ahead of any tstms that do develop. Confidence in MCS making it this far south is medium so will just go with VCTS for now. Otherwise winds should remain southerly with high pressure east and lee troughing west. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Billings Wright LONG TERM...Billings Wright AVIATION...Ewald
Area Forecast Discussion
National Weather Service Grand Rapids MI
1003 PM EDT Fri Jun 8 2018 LATEST UPDATE... Update .SYNOPSIS... Issued at 302 PM EDT Fri Jun 8 2018 Chances for showers and storms will remain possible over the weekend, however it will not be raining the entire weekend. Showers and storms will become likely overnight tonight, and will linger into the first half of Saturday. Rain chances will increase a bit again on Saturday night for areas further South and West. Rain chances then should diminish on Sunday. There is a good chance most of the area will remain dry on Monday with mild temperatures. This break will be short as the next system will arrive on Tuesday with chances of showers and storms. && .UPDATE... Issued at 1052 PM EDT Fri Jun 8 2018 A narrow area of showers that will likely become thunderstorms have developed from Coopersville to Grand Haven then about 10 miles off shore and that band is moving northward. These storms developed on the outflow boundary that moved north over western Lower Michigan, near the Lake shore, from the late afternoon convection south of Michigan in northern Indiana. It ran into an area of good 1000/805 moisture transport and some weak instability not to mention there is a MESO LOW centered near Grand Haven at 930 PM helping the cause with low level convergence. The upstream MCV moving into the area will help the cause to. So this area of convection should continue to move northward over the next few hours. Expect brief heavy rainfall with this convection mostly west of US-131 and from Muskegon northward. Additional showers will move into the area after midnight from the MCV currently over Wisconsin. The latest RAP models shows excellent moisture transport between 5 am and 10 am into our central CWA. So I would expect more widespread showers / thunderstorms at that time. && .SHORT TERM...(This evening through Sunday night) Issued at 302 PM EDT Fri Jun 8 2018 Our focus of the forecast is to try to figure out shower/storm trends through the weekend. As has been mentioned previously, weak features based on upstream convection will keep the forecast somewhat uncertain through the weekend. We have one short wave/MCV that is currently just exiting Chicago, which is supporting the showers and storms near and south of the MI/IN border as of 19z this afternoon. A few spotty showers or storm may affect the I-94 corridor through mid-evening, however most areas north of that should remain dry through sunset. Better chances for rain will come after midnight, and will linger likely into the first half of Sat. These shower/storm chances will be the result of another wave that is exiting IA near the Quad Cities this afternoon. This wave will spread pcpn into the srn counties overnight as the nose of the low level jet moves along I- 94. The models are fairly consistent in bringing most of the CWFA rain as an area of mid level fgen moves through the central and northern portions of the area, likely due to the H850 front over the area in a NW-SE orientation. Instability will pretty much be all elevated in nature, limiting the severe threat. Pwats over 1.5 inches will allow for locally heavy rainfall to be the main threat, especially south. Tonight`s wave will slide east of the area by Sat afternoon, allowing a likely break from rain. This will be short lived as another wave that is expected to come out into the Central Plains this afternoon will approach Sat night. This looks to stay a little further south than tonight, as the sfc and elevated thermal gradients/fronts sink south a little behind the wave tonight. We can not rule out additional rain chances on Sunday over the far South and West as the fronts are not too far away. The difference for Sunday is that the upper ridge to our west sharpens up due to the western low, and yields more of a NNW flow aloft to keep pcpn further west. We will keep some low chances of rain in to account for this. .LONG TERM...(Monday through Friday) Issued at 302 PM EDT Fri Jun 8 2018 An upper ridge shifts east early next week and height falls are accompanied by sfc low and trailing cold front pushing through the Great Lakes region with showers and thunderstorms on Tuesday moving off to the east and ending on Wednesday. There could be a few strong storms on Tuesday if there is enough sfc heating to generate instability. CAPE could spike over 1500 with a moist airmass in place and sfc dew points near 70. Forecast wind profiles look to be weak however, with only about 20 to 25 knots of deep layer shear. The main threat will be localized heavy rain and high wind gusts. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 736 PM EDT Fri Jun 8 2018 VFR currently prevails over all of the GRR TAF sites and through 06z I would think that would remain so. The main question is how the convection evolves overnight as a disturbance aloft moves over our area at that time. I based my forecast on a consensus of HRRR, HRRRX, NAMnest, and RAP model. These show the greatest likelihood of showers to be around sunrise. There is good agreement with these models that MVFR or IFR cigs will prevail then too. Seems the low clouds get trapped and may hang around a good part of the day once they move in. && .MARINE... Issued at 302 PM EDT Fri Jun 8 2018 We are not expecting any marine headlines to be needed through this weekend. Winds will be elevated somewhat, but should generally remain under 20 knots through the weekend. Winds will also generally have an offshore component which will limit wave heights. The exception to this will be possibly higher near any storms that move through. The better chance of that happening will be further south. && .HYDROLOGY... Issued at 302 PM EDT Fri Jun 8 2018 Excessive rainfall remains a small possibility late tonight and Saturday as pool of higher precipitable water values currently over nrn IL nudges this way. Latest RAP guidance is suggesting the development of a 25-30 kt low level jet aimed into southwest Lwr MI by early Saturday morning along with PWATs of 1.75 to 2 inches. It seems like the better potential for excessive rain should be south of I-96 closer to the frontal boundary, but any mesoscale feature emanating out of upstream convection could set off some slow moving/training cells containing locally heavy rain just about anywhere in our area late tonight and Saturday. The possibility of localized 1-3 inch rainfall amounts continues to be a low confidence scenario in weakly sheared environment, but if and where it occurs we may see some small stream and poor drainage flooding. Larger basin averages such as the Grand and Kalamazoo would likely be limited, unless overall areal coverage of rain is higher than expected. Thus no big rises are expected on the mainstem rivers at this time. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...Ostuno AVIATION...WDM HYDROLOGY...Meade MARINE...NJJ
Area Forecast Discussion
National Weather Service North Platte NE
626 PM CDT Fri Jun 8 2018 .SHORT TERM...(This evening through Saturday) Issued at 328 PM CDT Fri Jun 8 2018 A severe MCS is forecast to develop early this evening, and move quickly east-southeast. SPC continues to suggest an enhanced wind damage threat this evening into the early morning. Isolated storms expected to initiate in northern Sheridan County, followed by scattered storms moving east into the northern panhandle. As suggested by the latest and recent HRRR model runs, a small convective cluster should begin to take shape across the nw Sandhills by 8 pm CDT. While damaging straight line winds the primary hazard, there is also the potential for some large hail. The thunderstorm forecast carries likely POPs across much of north central Nebraska this evening, and into portions of central Nebraska crossing midnight. The southward extent of chance POPs extend south to near Ogallala thorugh Stockville, with just a slight chance south of there. The severe weather potential is based on ML CAPES +35000 J/KG and 0-6km shear values of 25 kts. A dry layer around 850 mb will enhance the wind damage threat. The convective system should exit the eastern zones by 6 am CDT. Depending on the size and intensity of the system, locally heavy rainfall is also possible. A half to three quarters of an inch is possible across much of north central into parts of central Nebraska. Although not an immediate concern, localized flash flooding is possible mainly east of O`Neill through Burwell. On Saturday, the atmosphere should become fairly stable in the wake of tonights system, as the upper ridge axis extends across the Plains. Warm 700 mb temps near 15C across the Panhandle and southwest should act to inhibit any thunderstorms late afternoon as highs reach or exceed 90 degrees most areas. .LONG TERM...(Saturday night through Friday) Issued at 328 PM CDT Fri Jun 8 2018 A slight chance for storms Saturday evening across the northwest Sandhills as height falls begin to work into the region. Backed southeast winds into the Blackhills region to be favorable for storm initiation, which may move into the northwest Sandhills. Sunday will be hot with daytime highs reaching well into the mid 90s with upper 90s across parts of southwest Nebraska. The upper trough will force the cold front through the forecast area Sunday night or early Monday morning. With height falls occurring, and the associated cold front, thunderstorms are possible across the northwest half of the area overnight, although a few storms could develop further east. Cooler and more stable air will reside behind the front for dry seasonal conditions Monday and Tuesday. Highs in the upper 70s to lower 80s. By Wednesday, an upper ridge begin to build in, with a warm front lifting north across the plains. Temperatures warm into the mid and upper 80s Thursday-Friday. Thunderstorms chances return late Tuesday into Wednesday, as fast zonal flow interacts with a warm front lifting north. Another chance arrives Thursday night. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 626 PM CDT Fri Jun 8 2018 Forecast challenge involves extent of developing MCS in area and time of departure. Current thinking is for the storms in SD to move southeast once an organized large scale cold pool develops which is ongoing now, following the theta-E axis that is currently outlined by the cu field in satellite. Good moisture inflow and evolving LLJ should sustain the storms as they head further south. Did not bring them as far south as KLBF until after 04Z though that will have to be evaluated as the night progresses with consideration of additional storms to the west moving in. SREF probs not indicating much potential for widespread IFR cigs in the post-MCS environment toward morning though that is always a bit of a concern. Have left out for now. Once organized system moves out there should be mainly convective debris for the morning but mainly in the form of high level cloudiness. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Roberg LONG TERM...Roberg AVIATION...Stoppkotte
Area Forecast Discussion
National Weather Service San Francisco Bay Area
859 PM PDT Fri Jun 8 2018 .SYNOPSIS...Cool and breezy weather is forecast region-wide on Saturday as an upper level system pushes inland to our north. Slight warming is forecast for Sunday, although breezy conditions will continue. Robust warming is then expected on Monday and Tuesday as high pressure builds over California. Temperatures are expected to return to near seasonal during the second half of next week. && .DISCUSSION...As of 8:55 PM PDT Friday...Evening satellite shows an unseasonably deep and cold upper trough off the coast of the Pacific Northwest. A surface cold front is currently spreading rain into coastal Washington and Oregon. Latest NAM and HRRR models show rain with the cold front making it as far south as Point Arena by late tonight, but not quite making it into Sonoma County. In any case, we may see some patchy drizzle overnight and into early Saturday as the surface boundary interacts with the marine layer. The primary impact of this incoming system will be cooling tomorrow, along with breezy conditions. Highs on Saturday are forecast to be as much as 15 degrees cooler than today as 850 mb temperatures drop as low as 4 degrees C in the North Bay. West to northwest winds will increase by midday tomorrow and breezy to locally blustery conditions are expected by afternoon. Wind gust of between 30 and 40 mph are likely during the afternoon and evening hours. The marine layer will definitely mix out by midday tomorrow. The upper trough is forecast to move well off to our east by Sunday and slightly warmer temperatures are expected during the second half of the weekend. However, breezy conditions are expected to persist through Sunday evening. The models agree in building an upper ridge over California on Monday and Tuesday and reducing onshore flow as well. The result will be a robust warming trend early in the work week, especially inland. For example, Livermore`s high is forecast to increase from the lower 70s tomorrow to the mid 90s on Tuesday. Persistent onshore flow will keep most coastal areas from warming above the mid 70s on Monday and Tuesday. The ridge is forecast to weaken by the middle of next week as a trough moves inland to our north. Temperatures will begin to cool on Wednesday and then drop back to near normal by Thursday and Friday. && .AVIATION...As of 04:42 PM PDT Friday...For 00z tafs. Satellite imagery showing stratus developing along the coast. The marine layer is around 1200 feet but is expected to deepen late tonight as an upper trough moves through. MVFR cigs expected to move in late tonight, although confidence on exact timing and extent of intrusion is low. Winds remain gusty across the region this afternoon, especially around the SF Peninsula. Winds will begin to subside later tonight but will be similarly gusty again by late tomorrow morning and last into the evening. Vicinity of KSFO...05:30 PM PDT UPDATE...Strong westerly winds are causing bits of stratus to drift over the terminal, creating IFR conditions. This will likely continue as long as the winds remain gusty. VFR conditions should return this evening once the winds begin to ease. MVFR cigs are expected late tonight at around 10-12z. An Airport Weather Warning was issued due to gusty westerly winds until 03Z this evening. Gusts over 35 kt have already been observed. Winds will remain gusty into the evening before easing overnight. Westerly winds will increase once again late tomorrow morning. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...VFR conditions will prevail through tonight. Confidence is low on the timing of low clouds returning. Westerly winds around 15 kt will continue into the evening before subsiding overnight. Expect gusty westerly winds once again by late tomorrow morning. && .MARINE...As of 8:46 PM PDT Friday...Gusty northwest winds will continue across the coastal waters as an upper level trough and associated cold front move through the region tonight. Winds will remain gusty through at least the weekend as high pressure sits over the eastern Pacific. Afternoon and evening winds are expected to be gusty across the bays as well. Strongest winds are forecast along the coast, especially along the Big Sur coast where gale force winds will be possible starting tomorrow afternoon. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Pt Arena to Pt Reyes 0-10 nm SCA...Pt Reyes to Pigeon Pt 0-10 nm SCA...Pigeon Pt to Pt Pinos 0-10 nm SCA...Pt Arena to Pigeon Pt 10-60 nm && $$ PUBLIC FORECAST: Dykema AVIATION: AS MARINE: AS Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Omaha/Valley NE
602 PM CDT Fri Jun 8 2018 .SHORT TERM...(Tonight through Monday) Issued at 330 PM CDT Fri Jun 8 2018 Forecast concerns tonight and Saturday will be ongoing convection this evening, then the evolution of a mesoscale convective complex (or combination of complexes) forecast to develop over South Dakota/central Nebraska that move eastward overnight. Storm potential Saturday afternoon and evening along the front/outflow boundaries...chance for storms late Sunday night and Monday as a warm front lifts north and a cold front pushes across the forecast area. A midday...we did have some echoes develop along the Missouri River and in western Iowa and visible satellite imagery/obs had towering cumulus. The 17Z GRAINEX sounding around Ulysses showed that we had around 2800 J/kg with no cap and very steep lapse rates. Cloud layer shear was from 290deg at 12kts. PWAT was around 1.29 inches. Water vapor satellite imagery highlights the moisture from the southern Plains into the Ohio/PA Valley, over parts of the Central Plains, and moving onshore with the large closed low over the Gulf of Alaska. By 20Z...visible satellite imagery showed rapidly developing thunderstorms in northwest Iowa where SBCAPE is around 4000J/kg and pwat is pooled at 1.7 inches/surface convergence near the boundary and a mesoscale vorticity center. The SPC HRRR maintains convection in this area and drops it southeast this afternoon and early evening, so will maintain isolated thunderstorms in western Iowa and could try to build toward OMA. The models have a variety of solutions for how things will evolve overnight. The NAM/HRRR/ExpHRRR have thunderstorms develop in southwest South Dakota spreading eastward. A second area of convection is forecast to develop over central Nebraska and move east lasting into the early morning hours. The GFS has something similar and the EC splits the storms with one area going north of Nebraska and the other over central Nebraska shifting east. After any isolated evening convection, storms should hold off until toward midnight, then have scattered thunderstorms pushing across the forecast area overnight. The mid level warm temperatures could lessen the coverage as they move south of I80, however the moisture/wind fields are supportive of scattered thunderstorms with gusty winds possible. The H7 dewpoints of 8 to 10 deg could lead to heavy downpours of rain. Forecast soundings try to weaken then between 12-15Z...however instability returns for Saturday afternoon. The shortwave that helped to initiate and sustain the convection will be moving east of the area during the afternoon, however there may be a few lingering storms or storms that form on any outflow boundary. Highs Saturday should be in the upper 80s to lower 90s with heat indexes in the 90s with 90 to 100 south of I80. Isolated storms are possible Saturday night and a few storms could develop Sunday as the warm front lifts north. High Sunday should be even warmer with highs in the mid 90s and HIs around 100. Sunday night into Monday a cold frontal passage will bring more showers and thunderstorms with it. Highs in the 90s ahead of the front and lower to mid 80s behind it. .LONG TERM...(Monday night through Friday) Issued at 330 PM CDT Fri Jun 8 2018 Behind the cold front Monday night, surface high pressure builds and highs in the 80s are forecast for the next several days. A weak ripple Tuesday night and Wednesday could touch off a few storms. Ridging is forecast for Thursday and Friday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 602 PM CDT Fri Jun 8 2018 An MCS currently evolving over south-central SD will track southeast tonight, likely affecting KOFK in the 06z-10z time frame, and the KLNK and KOMA areas between 08z-13z. This system will likely be attended by variably gusty winds of 20-30+kt and temporary visibility reductions to 2-3SM. Cloud heights should lower to around FL040 within the thunderstorms. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Zapotocny LONG TERM...Zapotocny AVIATION...Mead
Area Forecast Discussion
National Weather Service Paducah KY
853 PM CDT Fri Jun 8 2018 .UPDATE... Issued at 853 PM CDT Fri Jun 8 2018 Based on the most recent radar trends and CAM data, the forecast has been updated to remove all PoPs until after daybreak. We will have to monitor the convective activity in northern Missouri closely, but the 00Z HRRR has a decent handle on it and kills it off before it gets to the KSTL area. UPDATE Issued at 650 PM CDT Sat Jun 8 2018 Updated aviation discussion for 00Z TAFs. && .SHORT TERM...(Tonight through Sunday night) Issued at 213 PM CDT Fri Jun 8 2018 Holding out and not including PoPs so far has worked out. RAP soundings hint of a CAP, especially west KY where other models did not. Seems to be holding. Would not rule out an isolated shower, but Red Channel vis showing little vertical development. Will keep PoPs 10 percent or less and continue to monitor. CAM`s models for the 19z time frame definitely over done (no surprise). NAM handling things fairly well. Otherwise, we will remain in a weak NW flow aloft with waves of weak energy moving over the region. At the surface, a frontal boundary will remain just north of the region. The result will be continued above normal temperatures, and a chance of convection through the period. Marginal severe weather risk per SPC will be mainly isolated strong winds and perhaps marginally severe hail. Locally heavy rain possible. .LONG TERM...(Monday through Friday) Issued at 213 PM CDT Fri Jun 8 2018 Medium to high confidence in the extended concerning continued heat and humidity. Fairly high confidence in isolated to scattered thunderstorms each day or night. Low confidence on the exact timing of the storms. Models continue hold the upper high over the southwest but it does indicate some building to the east during the week. However the northwest flow over the forecast area appears to hold in place over the area. We will start Monday with a stalled cold front bisecting the area...lifting back north as a warm front in tandem with the high building eastward. This will create at least a chance of thunderstorms mainly east or northeast portions of the region. Tuesday we will be in the warm sector with a low to our north and a cold front to our west and a trough over the mid Mississippi Valley. This will rain chances going for Tuesday. By Wednesday the trailing cold front will move into the forecast area and stall...keeping rain chances going. Thursday the front will remain stalled over the region. Friday into the weekend the upper level trough finally starts to rotate out of the region This could end or at least mitigate the rain chances as we head into the weekend. Through the addition to the synoptic scale kickers...we will also have outflow boundaries and possibly MCV to move through the area. We expect diurnal chances of storms during max heating of the day...but these other features I mentioned could come through in the night time hours keeping rain chances going even after peak heating. In addition daytime CAPE values will range from 3k to 4k j/kg2 with LI`s approaching double digits. So any storms that do get going will have the potential to be strong or even severe. In contrast the most widespread threat will be heavy rain and lightning. The wind shear or profiles do not appear as much of a threat as typical with this summer like air mass. Temperatures will remain above normal through the extended for both highs and lows. && .AVIATION... Issued at 650 PM CDT Fri Jun 8 2018 VFR conditions are forecast to persist through the period with light SSW winds. Isolated convective chances are also present as a weak wave of energy acts upon an increasingly humid air mass. Best chance is timed with PROB30 groups from late morning through mid afternoon in coincidence with peak heating. While more mid and high clouds are expected through the period, expect low cumulus to remain few to scattered, except near thunderstorms. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ UPDATE...DRS
Area Forecast Discussion
National Weather Service Shreveport LA
1047 PM CDT Fri Jun 8 2018 .UPDATE... While storm intensity has weakened over the last couple hours, still dealing with scattered convection across Southeast Oklahoma and Southwest Arkansas late this evening. An MCV has formed across SW AR in response to this convection which is helping to sustain the coverage at such a late hour. For this reason, will need to carry pops into the remainder of the overnight hours in the vicinity of SE OK and SW AR. The HRRR even depicts the possibility of new development overnight south of this area closer to the LA/AR border in the vicinity of a remnant outflow boundary left over from this convection. Cannot rule this possibility out either for the remainder of the night. Concerning temps, updated hourly fcst temps to reflect current temps from the rain cooled airmass across our northern zones. Should not see much more falling of these temperatures overnight. Also had to adjust dewpoint and sky grids to account for current trends as well. Update out shortly...13. && .PREV DISCUSSION... /issued 628 PM CDT Fri Jun 8 2018/ UPDATE... Will need an update to add pops to the evening hours across SE OK and SW AR where a weak disturbance aloft continues to interact with late afternoon heating to produce strong thunderstorms. This activity has shown very little movement over the last hour but outflow emanating from the storms may result in additional storms developing further south and west of present convection. For this reason, have only gone with high end chance pops across our extreme northern zones bringing slight chance pops as far south as a few parishes in Northern Louisiana north of the I-20 Corridor. This convection, much as was the case last night, should begin dissipating in coverage and intensity over the next 3 hours or so. Update out shortly...13. PREV DISCUSSION... /issued 437 PM CDT Fri Jun 8 2018/ AVIATION... Convection currently across Central Arkansas associated with a weak upper level shear axis. This feature is providing the lift necessary along with the instability of afternoon heating to produce scattered thunderstorms. HRRR suggests that this activity could push southward towards the TXK/ELD terminals so for the 00z TAF package, have prevailed VCTS until 02z when the convection should begin dissipating in coverage and intensity. Otherwise will just be dealing with debris cloud cover from this convection across some terminal locations overnight. Otherwise, VFR conditions are expected to prevail through the next 24 hours. Light southeast winds overnight will become S/SE near 10kts or less beyond 09/14z. 13 .PRELIMINARY POINT TEMPS/POPS... SHV 74 94 73 93 / 10 10 0 0 MLU 72 93 72 93 / 10 10 10 10 DEQ 70 92 69 92 / 60 10 0 0 TXK 74 91 72 93 / 30 10 0 10 ELD 72 92 71 93 / 30 10 0 10 TYR 74 92 73 92 / 10 10 0 0 GGG 74 93 72 93 / 10 10 0 0 LFK 72 94 73 92 / 10 10 0 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 13/13/13