Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/21/19

Area Forecast Discussion
National Weather Service Bismarck ND
923 PM CDT Sat Jul 20 2019 .UPDATE... Issued at 921 PM CDT Sat Jul 20 2019 The forecast for tonight remains in good shape. Blended latest observations to hourly forecast elements for this update. Still on track for increasing chances for precipitation overnight. UPDATE Issued at 614 PM CDT Sat Jul 20 2019 Main change for tonight and into Sunday morning was to increase POPs a bit as a strong S/WV trough swings across the Northern Plains. Models are nearly in sync with each other with QPF placement and timing. This change resulted in likely shower mention across the southwest and far south central late tonight through the Sunday AM hours. Will keep thunder wording as a `chance` with scattered activity expected. Otherwise, the forecast for tonight remains in good shape. && .SHORT TERM...(This evening through Sunday) Issued at 123 PM CDT Sat Jul 20 2019 The main forecast issue in the short term period will be shower and thunderstorms chances on Sunday, and daytime highs Sunday. Latest satellite imagery shows sunny skies across western and central North Dakota. There was some shower activity over southern portions of Saskatchewan and Manitoba that may yet sneak across the border later this afternoon or early evening. Think this will be very isolated in nature and latest RAP soundings show instability is pretty much capped above 10-12K ft so if anything we could see a brief shower or sprinkle. Current shower activity will be moving into a drier environment as the approach the ND border. A closed upper level low currently located over far northern Idaho will move east across Montana tonight and is forecast to be over northeast Montana by 12 UTC Sunday, and will move east along the International border into northwest Minnesota by late Sunday afternoon. The upper low weakens through this entire period. However, the low itself, and a strong compact upper level jet rotating around the base of the low will produce scattered showers and possibly some isolated mainly afternoon thunderstorms. The most likely area for precipitation early Sunday will be the far southwest and south central, which will be under the right entrance region of the aforementioned jet. Lighter precipitation will be confined to near the International border, near the mid- upper level circulation. With daytime heating, we should see some marginal CAPE of around 500-800 J/kg, enough to support a few thunderstorms. Possibly from around Williston and Minot southeast to Bismarck and Jamestown, with lesser chances over southwest North Dakota. Shear is quite strong earlier in the day but diminishes quickly by the afternoon, so at this time severe weather is not anticipated. The increased cloud cover with this upper level system will result in high temperatures generally in the low to mid 70s on Sunday. Lingering convection over the south central will diminish Sunday evening, then mostly clear conditions late with overnight lows mainly in the 50s. .LONG TERM...(Sunday night through Saturday) Issued at 123 PM CDT Sat Jul 20 2019 Dry with warming temperatures highlight the extended forecast period. Monday through Wednesday will see the development of a large downstream h500 trough east of the Mississippi Valley, with an upstream h500 ridge over Montana/Idaho. This pattern will bring broad subsidence to the region and maintain dry weather for the northern plains through Wednesday. We expect a slow warming trend also during this period as the ridge axis slides east, from the 70s to around 80 on Monday, to the lower to middle 80s Tuesday, to the 80s to around 90 Wednesday and Thursday. Another cold front is expected to arrive on Thursday night and Friday bringing a bit cooler air and scattered thunderstorms to the region. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 614 PM CDT Sat Jul 20 2019 VFR conditions are expected through the forecast period. We will see showers and a few thunderstorms move into southwest North Dakota early Sunday morning and spread east and slightly north. This continues Sunday afternoon central and east. Will keep VCTS out of the terminal forecasts for now due to their low predictability. Will continue to carry a VCSH for those terminals likely to see some rain. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...TWH LONG TERM...TWH AVIATION...NH
Area Forecast Discussion...UPDATED
National Weather Service Cheyenne WY
756 PM MDT Sat Jul 20 2019 .MESOSCALE UPDATE... Issued at 756 PM MDT Sat Jul 20 2019 We cancelled the Severe Thunderstorm Watch for Laramie County given instability is dropping and diminished risk for getting stronger updrafts. We will leave PoPs in the 50 percent or so range given scattered showers moving in from the west. Also will raise PoPs a bit for the Chugwater and Wheatland areas next couple of hours. Otherwise...raised PoPs a small bit farther east into the Nebraska Panhandle as this area of showers and isolated thunderstorms moves east late this evening and overnight. && .SHORT TERM...(This evening through Sunday) Issued at 232 PM MDT Sat Jul 20 2019 Latest satellite loop was showing some towering cumulus developing over the Laramie Range. However, the bulk of the convection is currently along the Colorado Front Range. The Colorado Front Range does not appear to be as capped as our forecast area today. Low clouds have been fairly stout this afternoon due to CINH values (200-300j/kg) after the passage of the frontal boundary earlier this morning. Therefore, we are thinking that this convection developing over the Laramie Range may weaken a bit as it pushes east into the capped region during the next hour or so. However, as the afternoon wears on, the cap should begin to weaken resulting in better upscale growth. The latest HRRR guidance was showing the convection being delayed from previous runs. This may be a result of it underdoing the cap. The NAM depicted this cap being a little stronger today and keeps most of the convection along the Laramie Range and mostly west of Cheyenne. However, during the last hour or so, we have seen a bit more thinning of the clouds which is indicative of the cap trying to erode. SPC just issued a watch for Laramie county through 11pm, but at this point we believe that the best threat for this convection will be between 6pm and 9pm with the main threat being large hail, due to it being more elevated. Later tonight we will most likely see low clouds/patchy fog develop along and east of the Laramie Range, due to copious amounts of low level moisture in place. In fact, we may have some dense fog along the foothills and I-80 summit. Another frontal boundary is progged to move through the area on Sunday. Tough to say how deep this boundary will be, but the moisture will continue be quite deep. Therefore, one cannot rule out more thunderstorm development along the Laramie Range. .LONG TERM...(Monday night through Friday) Issued at 257 AM MDT Sat Jul 20 2019 The extended forecast period will be characterized by a typical mid- July weather pattern across the central Rockies, w/ quasi-zonal flow aloft on the northern fringe of broad & flat ridging anchored across the southwestern CONUS. Numerous mid-level disturbances are expected to traverse the flow, but in general we can anticipate daily chances for convection across southeast WY and the western NE Panhandle thru much of the week, mainly in the afternoons & evenings. Any risks for severe storms will depend on the timing of individual waves, but the potential will exist for parts of the area next week. Otherwise, the general outlook features afternoon highs in the 80s (perhaps low 90s in the Platte River Valley), and light winds each day. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 756 PM MDT Sat Jul 20 2019 Will keep mention of showers going for Laramie and Cheyenne, with a showers or thunder vicinity farther east into the Nebraska Panhandle. Brought in a period of IFR/LIFR ceilings with MVFR ceilings to most of the Panhandle late tonight into tomorrow morning given favorable moisture and wind profiles. && .FIRE WEATHER... Issued at 232 PM MDT Sat Jul 20 2019 Fire weather conditions will be quite minimal this weekend, due higher daytime humidities. However, if we do receive a lightning start we may have some potential for gusty northeast winds resulting in larger spread. Drier conditions are anticipated next week. This combined with afternoon thunderstorms may result in the potential for any start to become more explosive. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ UPDATE...JG SHORT TERM...REC LONG TERM...CLH AVIATION...JG FIRE WEATHER...REC
Area Forecast Discussion
National Weather Service Grand Junction CO
549 PM MDT Sat Jul 20 2019 .SHORT TERM...(Tonight through Sunday night) Issued at 306 PM MDT Sat Jul 20 2019 A weak shortwave, that brought some early morning thunder to the region, continues to move across Colorado at this hour bringing more showers and storms to the San Juans and areas along the Continental Divide. A few stray returns are showing up for the Grand Mesa and Moffat county so bumped up PoPs a bit to account for this. Later shifts will need to keep an eye on this convection and bump up PoPs, if appropriate. The NAMNEST and HRRR are both handling this convection fairly well and have all showers and storms ending by 8PM. As peak heating ends, and the upper level support shifts to the front range, it follows that convection will die so forecast follows suit. Winds will become more northerly, for the most part, which will usher in some drier, and cooler, air. A drier day is in the forecast on Sunday as PWATs lower. Light westerly flow is expected aloft with light west to southwest flow at the surface. An isolated shower or storm can not be completely ruled out along the divide given a bit of remaining instability to the east, however any showers will diminish quickly before sunset. Expect similar high temperatures across the western slope on Sunday as were seen on Saturday. .LONG TERM...(Monday through Saturday) Issued at 306 PM MDT Sat Jul 20 2019 A large amplitude area of high pressure will be centered over our CWA Monday and persist through much of the week. Subsidence aloft will cap most convection as well as decreased moisture though a stray shower or storm may be possible along the highest peaks of the Continental Divide for Monday and Tuesday. While we remain mostly dry, models continue to indicate a stream of moisture moving up from the south but only reaching Arizona and New Mexico through midweek. Wednesday onwards, this moisture looks to get entrained in the anticyclonic flow and as a weak wave drifts across the northern tier states, this moisture finally moves into our area. Mid to long term models have been fairly consistent showing an uptick in convection and rainfall Wednesday through Saturday. While the moisture tap isn`t as apparent, some hints of it remain. Expecting most of the convection to be recycled moisture from the initial push. Temperatures will start out fairly warm and from midweek onwards, increased clouds and precip will drop daytime highs a few degrees. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 541 PM MDT Sat Jul 20 2019 Showers and thunderstorms will diminish in intensity through the evening in northern and central Colorado. HDN, EGE, RIL and possibly ASE may see a few more brief bouts of rain with some thunder before things die down around sunset. CIG and VIS will remain VFR, however an isolated heavier storm could briefly reduce HDN and EGE to MVFR or break ILS CIG thresholds. Expect clearing overnight with VFR at at all terminals throughout the day on Sunday. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...TGR/MAC LONG TERM...TGR AVIATION...MAC
Area Forecast Discussion
National Weather Service Lincoln IL
737 PM CDT Sat Jul 20 2019 .UPDATE... Issued at 737 PM CDT Sat Jul 20 2019 Had to make some significant updates to the forecast for the western CWA for tonight. MCS across Iowa continues to grow, with storms riding along the earlier mentioned outflow boundary. Latest radar imagery shows the line of storms starting to cross the Missouri border, and is likely to clip the western CWA in a couple hours. Severe thunderstorm watch was recently issued from about Peoria-Petersburg westward to account for this possibility. The boundary itself is now edging into the far northern CWA, and should provide a significant cooldown as it makes it further into the area. In terms of other headlines, the northern half of the Excessive Heat Warning was allowed to expire at 7 pm. The southern half remains in effect through Sunday, though as previously mentioned, there is considerable uncertainty with the portion north of I-70. Will defer to the overnight shift for any changes after the evening models arrive. && .SHORT TERM...(This evening through Sunday) ISSUED AT 328 PM CDT Sat Jul 20 2019 A well-defined outflow boundary generated by a cluster of convection that tracked from northern Iowa to the Illinois/Wisconsin border is sinking southward this afternoon...with 20z/3pm satellite/radar imagery showing it extending from north of Moline to near Omaha. A few thunderstorm cells have developed across northeast Iowa over the past couple of hours; however, the remainder of the boundary is inactive. With a well-capped airmass to the south characterized by a maximum warm layer temp of 23C at 850mb, think additional development is unlikely. As a result, will carry dry conditions across the board through the evening hours. Additional convection will develop on the nose of a low-level jet across central/eastern Iowa later this evening...with this activity gradually developing southward into the northern KILX CWA overnight. Model solutions vary, but a clear slowing trend has been noted on successive runs of the HRRR indicating storms may not arrive in the Peoria area until dawn Sunday. Have scaled back PoPs accordingly...with likely limited to locations along/northwest of a Rushville to Minonk line well after midnight. The consensus of CAMs suggests the early morning convection will tend to dissipate north of the I-72 corridor Sunday morning, with perhaps little re-development until late afternoon across the SE CWA. Based on good model agreement, have carried likely PoPs along/northwest of a Rushville to Minonk line through early morning, then along/southeast of I-70 after 21z as storms fire along the prevailing outflow boundary from the morning convection. Due to cloud cover and scattered showers/storms, temperatures will be considerably cooler on Sunday...with highs remaining in the 80s across the northern half of the area. Given expected cooling, have dropped McLean, Logan, and DeWitt counties from the Excessive Heat Warning on Sunday. If current trends continue, additional counties will need to be dropped as well...with 100 plus heat index values limited to locations along/south of I-70. .LONG TERM...(Sunday night through Saturday) ISSUED AT 328 PM CDT Sat Jul 20 2019 The outflow generated convection will exit the SE CWA by early Sunday evening; however, additional scattered activity will be possible Sunday night into Monday morning as the trailing upper short-wave tracks through the region. Once this feature and its associated cold front pass, all solutions point to deep N/NW flow and a period of below normal temps for much of next week. In fact, the latest MEX guidance suggests highs struggling to reach 80 degrees Monday through Wednesday...with overnight lows dipping into the upper 50s and lower 60s. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 624 PM CDT Sat Jul 20 2019 Quiet in the very short term, but some challenges with wind shifts and convective chances further into the evening. Latest surface obs and radar show a well defined wind shift dropping southeast toward KGBG. Time-of-arrival tool would suggest it reaching KPIA toward 04-05Z if it keeps on the current track. Meanwhile, thunderstorms across central Iowa have been moving southeast toward the western extension of the boundary. Most of the high-res models aren`t handling that very well, though the GFS is close and hints at an arrival at KPIA around mid to late evening. Have added a mention of VCSH there beginning 04Z and moved up the TEMPO MVFR period as well. Elsewhere, have kept the mentions more vague (VCTS/VCSH) for now, with some adjustments in time. By late Sunday morning, winds will be shifting toward the north as a cold front pushes through, which should mark an end to the rain chances. && .ILX WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 7 PM CDT Sunday for ILZ044>046- 049>057-061>063-066>068-071>073. && $$ UPDATE...Geelhart SHORT TERM...Barnes LONG TERM...Barnes AVIATION...Geelhart
Area Forecast Discussion
National Weather Service Melbourne FL
905 PM EDT Sat Jul 20 2019 .DISCUSSION... Diurnal convection has concentrated over the west FL Peninsula this evng...over east central FL it has all but burned itself except for isold shras/tsras over west Okeechobee county. Latest RAP40 analysis shows the H100-H70 Bermuda Ridge axis bisecting the FL Peninsula from E/NE to W/SW...generating 5-10KTS of S/SE flow acrs the CWA. Low/mid lvl moisture is on the modest side with H100-H70 mean RH values btwn 70-75pct, H85-H50 avg dewpoint depressions btwn 5-7C. Dynamic support is weak with upstream mid lvl vort/omega fields and upr lvl divergence fields largely flat...strong pockets of these fields are noted over the west central and northeast peninsula, but are assocd with lingering diurnal convection and will diminish once these storms dissipate. With the mean H100-H70 lyr as weak as it is, modest low lvl moisture, and negligible mid/upr lvl support, tsras over land seem too low to mention. The HRRR outperformed the 6KM WRF and it keeps the CWA more or less dry. Update will limit areal precip to the Treasure Coast, and only a slgt chc at that. && .AVIATION...Thru 22/00Z. Sfc Winds: Thu 21/04Z...E/SE 4-7KTS bcmg vrbl AOB 3KTS. Btwn 21/12Z- 21/15Z...bcmg S/SE 5-8KTS. Btwn 21/15Z-21/18Z...coastal sites bcmg E/SE 8-12KTS. Btwn 21/18Z-21/21Z...KMCO/KSFB/KISM bcmg E/SE 6- 10KTS...KLEE bcmg W/SW 6-10KTS. Vsbys/WX/Cigs: Thru 21/12Z...E of KVRB-KOBE slgt chc MVFR shras. Btwn 21/12Z-21/16Z...coastal sites slgt chc MVFR shras/IFR tsras. Aft 21/16Z...chc MVFR shras/IFR tsras all sites. && .MARINE... Favorable boating conds overnight as the lcl Atlc remains directly under the Bermuda Ridge axis. Light to gentle SErly breeze with seas AOB 2FT. Scattered showers/isold tstms south of the Cape. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ Bragaw/Sedlock
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
800 PM EDT Sat Jul 20 2019 .UPDATE...Latest RAP model has Atlantic high pressure stretching west across much of the Gulf of Mexico...with an axis through north-central FL through Sun. This will maintain abundant moisture...with model PWAT values around 2 inches and a prevailing southeasterly lower level flow. Although winds shift to onshore in Sun afternoon sea breezes. Sun is expected to be similar to today - sunny to mostly sunny in the morning then increasing clouds as showers and thunderstorms form mainly inland early afternoon and increase and congregate along the Gulf coast mid to late afternoon. The strong to severe thunderstorms of this afternoon are now winding down and slipping out over the Gulf and should exit coastal areas between 8 and 9 pm. However cloudiness and mostly light rain/showers will continue a bit later for some locations...clearing out by midnight. Overall the forecasts look good but will make minor near term adjustments to better refection ongoing conditions. && .AVIATION... 21/00Z TAFs. Afternoon convection has just about cleared all the terminals but will keep VCNTY remarks TIL 02-03Z from SRQ northward. Anticipate TSRA with PSBL MVFR/LCL IFR AFT 18Z. Winds become VRBL/easterly for overnight then pick up during Sun as they shift to SE then S or SW. && .MARINE... Prevailing southeast winds...except shifting to onshore an an afternoon sea 10 knots or less with seas 2 feet or less for the rest of the weekend. Main concern will be thunderstorms with locally higher winds and seas. High pressure currently across north-central FL settles down over south FL early next week with a southwest to west flow pattern setting up. && .Preliminary Point Temps/PoPs... TPA 76 91 76 91 / 30 40 30 40 FMY 75 91 75 91 / 20 50 40 50 GIF 75 93 74 93 / 30 60 10 60 SRQ 75 91 75 91 / 30 30 40 40 BKV 73 92 72 92 / 30 40 20 40 SPG 76 91 76 91 / 30 30 40 40 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE/AVIATION/MARINE...09/Rude UPPER AIR...27/Shiveley DECISION SUPPORT...13/Oglesby
Area Forecast Discussion
National Weather Service Tucson AZ
841 PM MST Sat Jul 20 2019 .SYNOPSIS...High pressure and warm temperatures aloft will limit thunderstorm development this weekend with just a few storms in the White Mountains and near the International Border. Increased moisture and a more favorable flow should result in an increase in thunderstorm coverage Monday and Tuesday before some drier air moves in around Wednesday and Thursday with reduced thunderstorm chances. && .DISCUSSION...For those of you in Tucson experiencing thunderstorm withdrawal, don`t look at the 21/00Z sounding. It`s not a pretty sight. PW is down around 1.1" without even a sliver of instability. That being said, some very impressive thunderstorm complexes developed this afternoon/evening in northern Sonora. This was the result of an inverted trough working through the Gulf of California and moisture should be increasing across our area due to these features. Dew points near Yuma are back into the 60s. Looking closer to home, it wasn`t a total shutout as a handful of storms developed and hugged the International Border in Santa Cruz County, but no gauges measured more than a few hundredths. Not expecting to see any activity overnight and tomorrow should favor our southern border yet again. For additional details about improving rain chances next week, please see the previous discussion below. && .AVIATION...Valid through 22/06Z. SCT-BKN clouds 12k-18k ft MSL this evening mainly along the International Border. Cloud cover will diminish overnight before SCT- BKN decks return Sunday afternoon, with isolated -TSRA/-SHRA south of KTUS. Surface winds generally less than 12 kts through the period, favoring WLY-NWLY direction Sunday afternoon with gusts up to 20 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Expect gusty afternoon northwest winds on Sunday across the Upper Gila River Valley. 20-foot winds elsewhere will generally be under 15 mph. The general trend of reduced shower and thunderstorm activity continues this weekend, with isolated cells along the International Border and across the White Mountains. Scattered to numerous thunderstorms are expected Monday afternoon and evening over much of southeastern Arizona. Broad thunderstorm coverage remains on Tuesday, decreasing by the middle of the week. && .PREV DISCUSSION...Another low grade monsoon day with below average moisture for late July. Precipitable water values around 75 to 80 percent of normals at 1.1 to 1.2 inches, but much deeper moisture is not far away. 1.5 inches in far northern Sonora with 1.8 inches as far north as the central Gulf and Hermosillo. For today we`ll have to settle for mainly border storms. We`re seeing some really good signals that will change things by late Sunday into Monday. First of all we`re seeing the start of a surge through the lower western deserts with Yuma dew points jumping back into the middle 50s (up 20 degrees over the past 24 hours). KYUX wind profile shows it`s just seeping in at this point with only 5 to 10 kts up to 5k feet. Storms are organizing quite nicely just south of the border with strong outflows pushing deep into our area on the HRRR ensembles this evening. The easterly impulse pushing from the Mexican coast into the southern half of the Gulf of California should help push the intensity of the surge over the next 36 hours. This alone would indicate a strong upturn in activity, but the best thunderstorm days for our corner of the state also engage an easterly moisture source. I like the latest NAEFS mean integrated WV transport with a push from southwest New Mexico and northern Chihuahua Monday and Monday night. GEFS plumes suggest at least 1.45 inches precipitable water by Monday afternoon, with operational GFS as high as 1.6 inches. NCEP SREF plumes argue for for a ML CAPE only in the 800-1k range, and H5 theta-e values are a tad high, but vigorous southerly outflow is likely from initial storm formation Monday afternoon. Interesting to note effective vertical wind shear in the 25-30kt range on SREF plumes as well. The main story for the lower deserts may end up being a strong chance at deep outflow from the Mogollon Rim as well for Monday afternoon and evening. That would put prime time for Pima and Pinal county valley locations after 5 PM. Dust could end up being a concern. Tuesday would likely be a recovery day if the Monday forecast works out. We`ll see on that. We will still have plenty of boundary layer moisture to recycle the second half of next week, but are unlikely to maintain a deep fetch of moisture with an easterly component to our mid level flow periodically drying out (with limited Gulf of Mexico influence). However, with the high center finally in a position where it wobbles back and forth overhead to northwest to northeast of us, the overall trend will be better. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Howlett Prev Discussion...Meyer/Pawlak Visit us on Facebook...Twitter...YouTube...and at