Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/28/20

Area Forecast Discussion
National Weather Service Goodland KS
239 PM MDT Mon Jul 27 2020 .SHORT TERM...(This evening through Tuesday) Issued at 204 PM MDT Mon Jul 27 2020 Through Tonight: Although a marginally unstable, uncapped airmass -- associated with atypically moist low-levels, moist- adiabatic (5.5 C/km) mid-level lapse rates, and late July insolation -- is in place over the Tri-State area early this afternoon, forcing is essentially absent, and convective development has thus far been confined south of Highway 50. Even there, low-level forcing is difficult to discern. The orientation/location of convection currently in Southwest KS and Southeast CO appears to be best correlated with a weak H7 trough/wind shift progressing southward into TX/OK. With the above in mind, little or no convective development (aside from extremely small/brief/isolated showers) is anticipated in Northwest KS. Tue-Tue night: Small amplitude shortwave energy situated over CA/NV this afternoon may progress ENE into portions of the Central/Northern Rockies on Tue (along the N periphery of the upper level ridge over the Desert Southwest) -- then E-ESE to the lee of the Rockies Tue night (along the NE periphery of Desert Southwest ridge). Significant uncertainty exists with regard to the extent of convective development along the Colorado Front Range Tue aft/eve, and significant uncertainty exists with regard to whether or not such activity would propagate into Western KS/Southwest NE -- or SSE through Central/Southeast CO. Simulated reflectivity forecasts via both the 12/18Z NAM NEST suggest little (if any) convection will even be present in Eastern CO Tue aft/eve -- while the 12Z HRRR suggests that there may be some potential for convection to progress downstream toward the CO/KS border Tuesday evening. .LONG TERM...(Wednesday through Monday) Issued at 145 PM MDT Mon Jul 27 2020 Wednesday and Thursday upper level winds return to a northwesterly flow, which will lead to afternoon and evening thunderstorm chances as highs on Wednesday range from the mid to upper 80`s. The main focus for storms on Wednesday will largely depend on if a surface low from the front range of the Rocky Mountains will be able to make it into our area; models are inconsistent if this will occur. A stationary front will stall in the area late wednesday night and will lead to the focus for a better chance of more rain and storms. Models are also inconsistent with the exact placement of the front, but do show measurable precipitation across the area, so a potential for a sharp gradient of precipitation may occur. Thursday will be cooler than Wednesday with high temperatures struggling to make it into the lower 80`s. Leading into the weekend discrepancies exist with the location of an upper level high. A shortwave trough will ride down the eastern portion of the ridge and over the Central Plains. Which may lead to the chance of precipitation. The placement of the system will determine the impact and timing of Fridays weather. A more eastward location will decrease the chance of any rain, while a more westward would enhance the lift over the area and create a better chance of measurable precipitation. Saturday and Sunday will be warmer and dry, but will need to be monitored due to the uncertainty of Friday`s shortwave. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1125 AM MDT Mon Jul 27 2020 Lingering MVFR ceilings are anticipated to lift/scatter to VFR early this afternoon (by 19Z). An isolated shower/storm cannot be ruled out at the GLD terminal this afternoon (18-00Z), however, probabilities are too low to warrant explicit mention with the 18Z TAF issuance. Otherwise, VFR conditions are anticipated to prevail late this afternoon through this evening. IFR-LIFR stratus may develop at both terminals early Tuesday morning, primarily in the 09-15Z time frame. Light (7-13 kt) NE-ENE winds will gradually veer to the E (this afternoon) and ESE-SSE (this evening/tonight). && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...VINCENT LONG TERM...TT AVIATION...VINCENT
Area Forecast Discussion
National Weather Service Indianapolis IN
1201 AM EDT Tue Jul 28 2020 .UPDATE... The AVIATION Section has been updated below. && .SYNOPSIS... Issued at 127 PM EDT Mon Jul 27 2020 A cold front will push across Central Indiana tonight. This will result in showers and thunderstorms this evening across the area. High pressure is expected to build across Central Indiana in the wake of the front on Tuesday and Wednesday providing drier and slightly less humid weather. A warm front is then expected to push toward Indiana on Thursday...bringing chances for additional showers and storms. Chances for showers and storms are expected to persist into the weekend. && .NEAR TERM /Tonight|/... Issued at 127 PM EDT Mon Jul 27 2020 Surface analysis early this afternoon shows a frontal boundary stretching from lower MI across Central IL to MO and OK. GOES16 shows CU development within the warm and humid air mass over Central Indiana. Dew points were in the lower 70s across the area...favorable for convection. Radar Mosaics show Thunderstorms development over IL and more isolated development over NE Central Indiana. Forecast soundings this afternoon and evening reveal a favorable setup for convection ahead of the approaching cold front with CAPE in excess of 2500 J/KG...pwats over 1.8 inches and convective temperatures which have been reached. The HRRR suggests widespread areal coverage of TSRA development late this afternoon..persisting into the evening hours as the cold front approaches. Thus will contain best pops to the 4-9PM time range as heating and upper forcing comes together best at that time. Time heights and forecast soundings suggest strong subsidence arriving within the column by 06Z as the cold front is expected to sag south toward the Ohio river. Thus after very high pops this evening...will trend pops sharply lower...toward dry...overnight in the wake of the front. Pops will linger longest in the southern parts of the forecast area where the cold front will exit last. Given our our expected slight change in air mass...will keep lows close to the NBM. && .SHORT TERM /Tuesday through Thursday/... Issued at 127 PM EDT Mon Jul 27 2020 Models suggest a deep cyclone in place aloft over Quebec and Ontario...influencing weather across the Great Lakes and Indiana. This along with strong ridging expected over the western plains will result in NW flow aloft on Tuesday and Wednesday. This results in subsidence and dry air in place aloft which is indicated within the forecast soundings and time heights. Forecast soundings on Tuesday and Wednesday are very dry with a good mid level inversion in place. Thus mostly sunny/partly cloudy sky will work well. Will not veer far from the NBM on temps given the slightly cooler air mass arriving across the area. On Wednesday Night and Thursday the GFS and NAM suggest a short wave exiting MO and pushing into Central Indiana before exiting late in the day. A weak surface warm front appears to remain in place across the southern parts of the forecast area...remaining a focus for lower level convergence and convective development. Forecast soundings on Thursday return to favorable conditions for precip with the column showing more saturation and pwats once again over 1.80 inches. Thus will trend pops upwards starting on Wednesday night and into Thursday with highest pops found near the front across the southern parts of the forecast area. Given the expected clouds and possible precip will trend highs at or below the NBM. && .LONG TERM /Thursday Night through Monday/... Issued at 228 PM EDT Mon Jul 27 2020 Models are in good agreement through the long term leading to good confidence in guidance output... thus have accepted it. Temperatures will be below normal throughout the period with highs near 80 and low in the mid to low 60s. This is due to predominately N to NW flow aloft. Models do show a couple of systems impacting the area, leading to chance PoPs for much of the time, but most of the lift looks to stay to the south of the forecast area, which is where the bulk of PoPs will be. Best chances of rain and storms for central Indiana look to be Sunday as a low pressure system passes across the area. && .AVIATION /Discussion for the 28/06Z TAF Issuance/... Issued at 1149 PM EDT Mon Jul 27 2020 Ceilings continue to fluctuate from IFR to VFR at TAF sites at this time, but expect this to start leveling out after Tue 06Z. VFR should become the predominant flight category early Tuesday morning. Will continue to monitor showers slowly approaching from the northwest, but they have not intensified over the last few hours and confidence is not high enough to include mention at KIND at this time. Meanwhile, winds will be light and variable. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...Puma NEAR TERM...Puma SHORT TERM...Puma LONG TERM....KH AVIATION...TDUD
Area Forecast Discussion
National Weather Service Louisville KY
843 PM EDT Mon Jul 27 2020 .Forecast Update... Issued at 842 PM EDT Mon Jul 27 2020 Forecast remains largely on track this evening. Most convection has tapered down across southern IN and central KY. However, a new area of showers and storms have started to develop in southwestern IN and southern IL. Most of this activity, as well as any that develops across central IN, should push into the region within the next hour or two and likely persist for a good portion of the overnight hours. The biggest concern with overnight convection will be heavy rainfall given the high PWATs in place. It`s possible it could lead to a low- end, isolated minor flood threat where storm training occurs. While individual storms will be unlikely to cause any flooding issues due to modest storm motions (15-20mph), some high-res models like the HRRR show convection developing in a east-west oriented manner that would support a few areas seeing repeated storms over a short duration. && .Short Term...(This evening through Tuesday) Issued at 255 PM EDT Mon Jul 27 2020 Believe it or not, even with precipitable water approaching 1.8 inches, Kentucky is in a local min right now, with PWATs over 1.9 inches in middle Tennessee and right at 2 inches in the Wabash Valley. So unsurprisingly, the favored areas for convection late this afternoon and into early evening will be near the KY/TN line, and more so over southern Indiana. A decent line or storms is making its way from eastern Illinois into west-central Indiana, and with the better dynamics to our north the SPC Marginal Risk makes plenty of sense. Could see a few strong storms into southern Indiana, with a pulse wind threat, but with weak flow and copious moisture, torrential rainfall could be as much or more of a threat. There also appears to be an opportunity for two waves of storms in southern Indiana, which could further support a flood threat with the second round. Tonight a weak cold front will sag into Kentucky, helping to focus showers and storms a bit deeper into the evening. However, with instability waning the convection will eventually die out toward midnight. For Tuesday it appears the front gets enough of a southward push that some slightly lower dewpoints filter into southern Indiana and north-central Kentucky, while the oppressively muggy air and focus for storms end up back across southern Kentucky. Heavy rainfall will remain the primary hazard. .Long Term...(Tuesday night through Monday) Issued at 255 PM EDT Mon Jul 27 2020 As we move into the long term, the main focus will remain on the frontal boundary that is expected to settle across the lower OH Valley for much of the period. For Wednesday, as the environment south of the front remains moist and moderately unstable, expect scattered showers and storms to develop, with best chances over south-central KY. Meanwhile, areas north of the front will see just slight chance PoPs as drier air advects in behind the front. Beginning Thursday, multiple waves of energy are then progged to move along the frontal boundary, resulting in unsettled weather continuing into early next week. As the first wave moves through Thursday, widespread showers and storms will be possible. PWATs are expected to increase into the 2.0-2.2 inch range as a LLJ advects abundant moisture into the area, leading to the potential for heavy rainfall and localized flooding issues. Another wave/closed low is then expected to lift through the OH Valley sometime over the weekend and into early next week, once again bringing chances for more widespread showers and storms to the area. Overall confidence in timing of these waves remains low as deterministic guidance continues to vary between models and runs. Wednesday is expected to be the warmest day of the long term, with highs in the mid 80s to lower 90s. The remainder of the period will then feature temperatures below climatological normals, with highs in the upper 70s to mid 80s. Low temperatures will generally be in the mid 60s to lower 70s. && .Aviation...(00Z TAF Issuance) Issued at 701 PM EDT Mon Jul 27 2020 Isolated to scattered showers and storms may persist for a good portion of the overnight hours as a weak frontal boundary slides into the region. Confidence in the predictability of these showers and storms remains low, but any site that does see one could see brief IFR/MVFR reductions in visibility. IFR/MVFR stratus may develop near sunrise toward the I-64 corridor, and slowly lift during the daylight hours tomorrow. Additional showers and storms may fire off near the frontal boundary in s-central KY tomorrow afternoon. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...DM Short Term...RAS Long Term...JML Aviation...DM
National Weather Service Morristown TN
918 PM EDT Mon Jul 27 2020 .UPDATE... EVENING UPDATE. && .DISCUSSION... Current radar imagery indicates an isolated storm across Claiborne Co. Elsewhere, scattered showers/storms have come to an end. For the update, increased PoPs in Claiborne and Hancock Counties to account for the lone storm and decreased PoPs in the near-term over the remainder of the forecast area. Overall, expect this storm will dissipate in the next hour or two. Expect the forecast area will remain dry overnight with patchy fog developing late tonight into early tomorrow morning. Due to the limited coverage of precipitation this afternoon and evening, do not expect any widespread or dense fog overnight. Overnight lows will generally be in the upper 60s to low 70s across the region. MA && .AVIATION... 00Z TAF DISCUSSION. VFR conditions currently across the terminals. Just a few lingering showers/storms across the area and do not expect any precipitation at the terminals this evening into the overnight hours. Patchy MVFR fog will be possible at TRI again late tonight into early tomorrow morning. Conditions should improve to VFR shortly after sunrise. Expect coverage of showers/storms will be more widespread tomorrow afternoon as an upper level trough moves across the region. MA && .PREV DISCUSSION... /ISSUED 319 PM EDT Mon Jul 27 2020/ SHORT TERM...(Today and Tuesday)... Upper level RAP analysis depicts two area of high pressure aloft, one centered over the four corners, and the second across the western Atlantic. This places the region between the two areas of high pressure with lowering heights in response to a trough sinking southward into the Great Lakes. At the surface, a cold front remains to the north across the Ohio valley. Infrared imagery and regional radar loops show convection has developed quickly early this afternoon in areas of 0-2km moisture flux convergence and differential heating owing to orographic effects. Thus far this convection has remained below severe limits with the highest 50 dbz echo tops only reaching ~20kft. While instability remains high, with CAPE values in excess of 3,000 j/kg, overall shear remains very weak. Area VWP`s only show 5-10 knot winds across the lower troposphere. This will keep organized strong to severe storm potential very low. However, cannot rule out localized gusty winds today with any downdraft. PWATs continue to run high today, generally around 1.50-2.00 inches. Localized heavy rainfall and possible flash flooding is also possible. Convection will wane with loss of daytime heating as we go into the night. Height falls overnight and low level convergence will present slight chance to chance PoPs through the night but any showers should remain fairly isolated. Lows tonight will range from the upper 60s to low 70s, a few degrees above climo. Tuesday, the shortwave continues to move through the local area with a cold front surging south into Kentucky before stalling out Tuesday afternoon. Another day of scattered showers and thunderstorms will develop in a moist and unstable airmass. Slightly stronger convergence from 925-800mb should help to increase coverage of showers and thunderstorms than what has been observed today. There is a slightly heightened threat for heavy rainfall and flash flooding on Tuesday given the increase in moisture through the column. Guidance has been showing the highest QPF axis across the Plateau, which is where the 925-850mb theta-e ridge is placed. Will continue to highlight a threat for flash flooding in the HWO. Highs tomorrow should be a couple of degrees cooler than today with highs in the low 80s to near 90. Diegan LONG TERM...(Wednesday through Monday)... The extended range fcst period kicks off on Tuesday evening amidst broad eastern CONUS H5 troughing, while ridging prevails over the western Atlantic and in the GOM. At the surface, troughing will extend southward across the Mid-Atlantic while a weak slowing cold front lays nearly atop or just west of the southern Appalachians, both extending from a parent low pressure system over the northeast. The aforementioned frontal axis looks to lay out across East TN and southwest VA/NC overnight into Wednesday, providing a focus for pulse convection through the day. Meanwhile the upper trough will slowly lift out of the southeast with deep layer flow backing swly as heights become more zonal by Wednesday into Thursday. With that, a shortwave and it`s associate surface reflection will traverse the mean flow aloft across the mid MS Valley into the TN Valley Thursday into Friday effectively surging the old boundary northward as a warm front allowing for improved/deeper (GOM sourced) moisture advection into the southern Appalachians per latest moisture transport vectors. Thus, model pwats surge into the 2.0-2.5 inch range regionwide which will present an increased threat for moderate to heavy rainfall with fcst QPF in 3-4 inch range through Friday night. Moving into the weekend, the initial shortwave will eject eastward while another H5 trough digs across the Plains states on Saturday, moving across the MS River into the OH/TN Valley region on Sunday. Height falls aloft will favor surface cyclogenesis with a surface low tracking east/northeast along the OH river, eventually dragging another cold front across the TN Valley on Monday. Confidence in the pattern late in the weekend remains low given some operational model discontinuity. Temperatures through the period will remain at or just below normal levels. CDG && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 73 90 72 87 73 / 20 60 50 70 70 Knoxville McGhee Tyson Airport, TN 72 89 72 89 72 / 20 60 60 70 60 Oak Ridge, TN 71 88 71 89 71 / 20 60 60 70 60 Tri Cities Airport, TN 69 85 68 87 69 / 20 60 50 70 50 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$
Area Forecast Discussion
National Weather Service Phoenix AZ
524 PM MST Mon Jul 27 2020 .UPDATE...Aviation discussion. && .SYNOPSIS... Isolated showers and thunderstorms will remain a threat across Phoenix and the surrounding higher terrain through Tuesday. Further west across southwestern Arizona and southeastern California, dry conditions will persist. High pressure will build across Arizona during the week, resulting in a continuation of the above normal temperatures and below normal precipitation chances. && .DISCUSSION... Latest water vapor imagery reveals a large swath of relatively dry air from the eastern Pacific, which is being transported northeastward into the Desert Southwest between an anticyclone across New Mexico and a trough along the CA coast. At the lower levels, latest observations indicate a relatively sharp gradient between drier air across western Maricopa County and higher dewpoint air near the Mazatzals. Meanwhile, isolated convection has already initiated in the moisture-rich environment across the Superstitions, which extends northwestward in a broken line all of the way into a low pressure system across the Great Basin. Morning KPSR sounding indicated a weak warm layer near 550 mb, which is still evident on the afternoon ACARS soundings. Further east, the environment remains more favorable for convection from eastern Maricopa County eastward where low-level mixing ratios exceed 12 g/kg and mid-level lapse rates are steeper. Pops were increased above the NBM across the higher terrain east of Phoenix for this afternoon. Main uncertainty is whether activity will spread into the Valley. Latest HREF continues to indicate a westward-propagating outflow boundary is likely. Main impact will be strong, gusty winds behind the gust front. However, instability should be sufficient for at least isolated storms in the foothills and perhaps in the Valley as well, which is suggested by some CAMs, including the U of A WRFs, HRRR and NAMNest. Although the setup is far from ideal, any storms that develop across Pinal would have the potential to produce areas of blowing dust. && .PREVIOUS DISCUSSION... During the week UL high repositions even further west over the Desert Southwest and AZ. As is does H5 heights and thicknesses increase to near 596-598 and 591-592 dam respectively by the end of the week. The high will be well positioned for the second half of the week to block moisture and storm chances for much of area. In addition this will really turn up the heat and the warm-up. Tonight and for the last several days models continue to trend even warmer. As a result an excessive heat watch has been issued for the lower deserts of AZ and SE CA for Thursday morning through Saturday evening. Highs across the lower deserts and Phoenix could now reach 111-112 through Wednesday, and 113-115 or possibly warmer for Thursday through Saturday with near record heat possible. High temperatures out west could reach upwards of 115-117 degrees. && .AVIATION...Updated at 0024Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: A couple outflow boundaries from the east/southeast are currently moving towards the Phoenix terminals. Thunderstorm activity has been struggling to survive along the boundaries, and thus it appears that these outflows will be the main story tonight. Wind gusts behind the boundaries are mainly in the teens, and speeds should continue to weaken as these boundaries continue to progress to the west-northwest. The first outflow should be making it into KIWA as we type this, and then there is still a little uncertainty on if either of the boundaries will make it to the rest of the terminals. If they do, it would be sometime between 1Z and 3Z. Once/if the boundaries go through, the winds should stay out of the southeast for the reminder of the evening before switching to a more westerly component early tomorrow afternoon. Few-scattered cloud decks near or above 10 kft should persist through the TAF period. Thunderstorm activity looks less active tomorrow afternoon. Southeast California/Southwest Arizona including KIPL and KBLH: Clear skies will persist at KIPL and mostly clear skies, with a few clouds around 10 kft, will persist at KBLH. Winds will favor the south-southwest at KBLH. At KIPL, winds will favor the southwest to west, before favoring the southeast tomorrow afternoon. && .FIRE WEATHER... Thursday through Monday: High pressure will build across Arizona, resulting in relatively dry conditions and well above normal temperatures with lower desert highs near 110-115 each day. Wetting rains are generally not anticipated Thursday and Friday. Thereafter, moisture will be on the increase during the weekend, which will be sufficient for at least isolated storms, particularly north and east of Phoenix. Min RHs will generally fall into the teens each afternoon. Overnight max RH should range around 25-40 percent. Meanwhile, winds will be mostly light and diurnal each day, except in the vicinity of thunderstorms. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Watch from Thursday morning through Saturday evening for AZZ530>556-559>562. CA...Excessive Heat Watch from Thursday morning through Saturday evening for CAZ561-563>570. && $$ DISCUSSION...Hirsch PREVIOUS DISCUSSION...Sawtelle AVIATION...Feldkircher/AJ FIRE WEATHER...Hirsch
Area Forecast Discussion
National Weather Service Pueblo CO
309 PM MDT Mon Jul 27 2020 .SHORT TERM...(This evening through Tuesday) Issued at 306 PM MDT Mon Jul 27 2020 Currently... Quite a few showers and isold thunder was occurring over the plains. Some of these relatively small showers were packing a punch, as several reports a quick inch of rain has occurred via gauge and spotter reports. Over the mtns the activity was more isolated but a few red pixels have started to show up in the last several volume scans. Obs show the atmosphere was quite moist as pwats per sat pix estimation were running about 150% above normal. Dewpts were in the mid 50s to mid 60s across the plains and 50s in the valleys. CDOT pics and pics on twitter show some flooding along the US50 corridor east of La Junta and in Lamar. Rest of today and into tonight... Main concern is flash flooding, with the primary concern over the burn scars. Guidance continues to indicate the best potential for heavy rain is going to occur in the Decker/Hayden Pass Burn scar areas, although a large area in Saguache county and Fremont county may get quite a bit for heavy rain per latest several HRRR runs. Will have to also keep a close eye on the plains as they storms are very efficient rain producers, and have already caused high water in places. Short range guidance shows the activity over the plains should gradually decrease as it moves southeast. Over the mtns, showers and storms will continue to increase, especially in areas from N Saguache county, western Fremont county and Chaffee county. This increasing rainfall will have the potential to cause flash flooding, especially in the burn scar areas. Areas of heavy rain capable of causing flooding will also occur in the San Juans. The showers and storms will likely continue in the mtns, especially along the divide, into the late evening and overnight hours. Over the plains, only isolated activity is anticipated. Tomorrow... Weather will return to a more classic pattern as storms will initiate in the mtns by late morning, with a band of showers and storms moving out onto the plains by afternoon. The only difference is that there will be a lot more moisture in the air then usual so we are likely going to have some flash flood problems in the mtns and plains tomorrow. Although storm should be moving to the east at a steady clip tomorrow, flash flooding will still be an issue over the burns scars. Guidance is hinting at a pretty robust MCV moving along the US50 corridor and this may lead to flash flooding issues over the US50 lower ark rvr valley area during the late afternoon and evening time period. Drier air should begin to move into the mtns by mid afternoon tomorrow, decreasing the heavy rain threat over the higher terrain. Since there is uncertainty in the guidance, will let later shifts decided if a flash flood watch is warranted for tomorrow. /HOdanish .LONG TERM...(Tuesday night through Monday) Issued at 306 PM MDT Mon Jul 27 2020 On Wed the upper level ridge center is expected to be over western AZ, with much drier conditions over southern CO. Just some isolated showers/storms will be possible, mainly over the far southeast plains and maybe over El Paso County and some of the mtns. With drier air in place, the temps will be warmer, with highs in the upper 80s and lower 90s over the plains, and in the upper 70s and lower 80s in the high valleys. Thu the upper ridge remains centered west of CO and a disturbance is forecast to move thru eastern CO, NE and KS during the afternoon and evening. With this disturbance, there may be some isolated to scattered storms over the far eastern areas. Afternoon low level upslope flow on Thu may help a few storms develop along the eastern mtns as well. High temps Thu may be just a couple/few degrees cooler than Wed over the plains, and slightly warmer in the high valleys. Fri and Sat the upper ridge center is forecast to be over northern AZ. It look fairly dry over southern CO on Fri with maybe just some isolated or scattered showers/storms over the higher terrain. Then on Sat the models show a disturbance in the flow coming over the top of the ridge. The models disagree on the strength and the mstr expected over southern CO, but there could be scattered pcpn over and near the mtns. For Sun and Mon the area remains on the front side of the upper high which is forecast to be centered over UT and AZ, with enough moisture over our area for at least scattered afternoon/evening pcpn, mainly over and near the mtns. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 306 PM MDT Mon Jul 27 2020 Afternoon showers and tstorms will be possible the rest of today and tomorrow. Locally heavy rain and gusty winds will be possible both time periods. Some low clouds will be possible at KCOS and KALS late tonight into tomorrow morning. A fairly robust line of convection may move across KCOS and KPUB late tomorrow afternoon or early tomorrow evening. && .PUB WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch until midnight MDT tonight for COZ061-062-067- 068-072>075-077-079-080-087. && $$ SHORT TERM...HODANISH LONG TERM...28 AVIATION...HODANISH
Area Forecast Discussion
National Weather Service Tulsa OK
720 PM CDT Mon Jul 27 2020 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. The main concern during this TAF period is going to be the redevelopment of showers and thunderstorms overnight tonight over the northern Oklahoma TAF sites. An MCV currently near the OK/KS border will continue to drift to the southeast into the overnight hours. Latest guidance suggests that TSRA activity will increase overnight across the northeast OK TAF sites and move east into northwest AR around or just after daybreak Tuesday. Expect prevailing MVFR conditions with embedded IFR conditions in the heavier thunderstorms. Elsewhere VFR conditions should prevail throughout much of the period with the possibility of more TSRA development Tuesday afternoon primarily for the eastern OK TAF sites. && .PREV DISCUSSION... /Issued 622 PM CDT Mon Jul 27 2020/ UPDATE... A flash flood watch has been issued for portions of northeast Oklahoma thru midday Tuesday. PoPs and QPF have also been increased across the region. See discussion below. DISCUSSION... The main player in the forecast for tonight into Tuesday morning is an MCV which is currently spinning near the OK/KS border to the northwest of Tulsa. The diurnal convection on the southeast fringes of the system in the more unstable air is waning across eastern OK, but not before dropping locally heavy rainfall /possibly as much as 3-4 inches/ in spots. Convection has recently fired up across northwest Arkansas, and this activity should wane as we head into the evening. The focus then turns back to northwest closer to the MCV, which should be drifting south or southeast tonight. A lot of CAM guidance suggests that storms will redevelop on its eastern and southern flanks overnight, more than likely affecting portions of northeast Oklahoma. Slow moving storms in an environment characterized by PWATs near or in excess of 2" suggests efficient rain production. In addition, portions of northeast Oklahoma have already picked up some heavy rainfall from this afternoon`s storms. Therefore, it is prudent at this point to issue a flash flood watch for portions of northeast Oklahoma thru midday Tuesday to cover the threat. Lacy PREV DISCUSSION... /Issued 302 PM CDT Mon Jul 27 2020/ DISCUSSION... An MCV to our west will be the focus for locally heavy rainfall overnight. The models differ in the placement of the heaviest rainfall, with all but the HRRR suggesting that the highest amounts will fall west of our forecast area. As such, will hold off on a flash flood watch at this time, but this will continue to be monitored. An upper ridge will continue to retrograde over the next few days, with an upper trof taking its place over the plains. Numerous rounds of showers and thunderstorms will be the result for the rest of this week, with locally heavy rainfall possible. Flood watches will become more likely as the week progresses. Temperatures will remain unseasonably cool with all the clouds and rain. The upper trof will shift east of the area by late this weekend into early next week, bringing clearing skies, but temperatures will remain below normal for the first of August. Stayed close to the National Blend of Models forecast. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...Flash Flood Watch through Tuesday afternoon for OKZ054>057- 059>061-064>066. AR...None. && $$ AVIATION.....04