Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/09/17

Area Forecast Discussion
National Weather Service Des Moines IA
606 PM CDT Sat Jul 8 2017 ...Updated for 00z Aviation Discussion... .SHORT TERM.../Tonight through Sunday/ Issued at 324 PM CDT Sat Jul 8 2017 Northwest flow continues over Iowa during the short term with several embedded and weak shortwaves riding through the flow. At the surface, high pressure will continue to slide off to the southeast with the axis of the high roughly from Marshall MN to just west of Mason City to Cedar Rapids then southeast. A surface low has developed over central NE with a weak surface trough/boundary extending into west central IA then into south central IA. Though moisture is lacking we are moderately unstable with CAPE`s increasing to 2200 J/Kg this afternoon and maintaining 1000 J/Kg overnight. The models yesterday had accurately depicted an area of lift coincident with this weak surface boundary and a mid level cloud field developed, along with a few sprinkles from west central into south central Iowa. During the evening this area of lift will shift into south central/southeast IA again, coincident with the weak surface boundary. The lift will be amplified to some degree by a weak shortwave passing through mid to late evening which could produce additional light showers or an isolated thunderstorm. This activity, should it develop, would pass to the southeast later this evening leaving the remainder of tonight dry but a little muggy as dewpoints increase solidly into the mid 60`s. There is a couple of items of concern for Sunday. First, the models have consistently developed an MCS over MN tonight and drop it southeast through Sunday morning. Past runs have scraped NE IA with this system through mid Sunday morning but latest runs now carry it well NE of the forecast area. While the trend was good, the chance for storms will still need to be watched based on where the storm complex develops and moves to, as the HRRR still has some semblance of precip scraping far NE IA. As the day progresses the surface low to the west will lift into South Dakota with a boundary extending across MN and WI. The weak surface trough over the East will evolve into a warm front as southwesterly winds increase and deepen. Meanwhile another shortwave will cross Iowa and if the timing is right, will interact with the frontal boundary and aid in the development of thunderstorms across eastern IA from mid to late afternoon into the evening. Models definitely depict a ribbon of theta-e advection along/ahead of this boundary and given the instability and DCAPE`s of 1500 J/Kg, some severe storms with damaging wind will be possible. LCL`s appear too high for much of a tornado least through 00Z. Shear values are best further north where the main boundary will be but are more modest over Iowa so at this point, I`m not real excited about large hail. However, if that warm frontal boundary over eastern Iowa is stronger than forecast, then shear would be much better and hail would have to be considered as a threat. Similarly to tonight, if storms do develop late day across the east, then they will likely intensify Sunday night as a low level jet increases some but should likely be further east of our forecast area. .LONG TERM.../Sunday night through Saturday/ Issued at 324 PM CDT Sat Jul 8 2017 The main forecast concern was focused on severe weather potential late Sunday night into Monday and with the heat building back into the region throughout the week. Models are in good agreement with the timing and location of shortwave to impact eastern Iowa tomorrow night into Monday and utilized a blend. Sunday night into Monday morning...Shortwave embedded within the 500mb northwest flow pushes southeast across southern Minnesota into northeast Iowa/northern Illinois between 06-12z Monday. Instability during this time should still be fairly good with MUCAPE values in the northeast ranging in 2000-3000 J/kg and SBCAPE around 2000 J/kg. DCAPE ranges in the 700-1000 J/k and low to mid level lapse rates in the 7.5 to 8 C/km range per MCW sounding by around 06-09z Monday. 0- 3km shear tops out at 40-50 knots and 0-6km shear over 50 knots tomorrow night per GFS across northeast portions of the forecast area. Mainly unidirectional shear profiles tomorrow night, especially when the shortwave moves across eastern Iowa. Mainly expecting a damaging wind and large hail threat. Storms look to be east of the forecast area by 12-15z and certainly confident enough to increase pops in the Slight Risk area. Monday afternoon through Friday...The heat and humidity build back into the region beginning Monday with highs along and south of Highway 30 likely to be in the 90s for several days. Dew points back into the lower 70s for much of the state should cause for some very uncomfortable heat conditions for an extended period. Heat index values in the afternoon look to top 100 degrees with the hottest day appearing to be Wednesday with mid-90s for temperatures and near 105 heat index readings for the southern half of the forecast area. If storms and cloud cover clear out quick enough on Monday, the temperatures/humidity will have a chance to recover even more so than the current forecast. Some relief is possible with a pop-up thunderstorm Tuesday afternoon and Thursday. && .AVIATION.../For the 00Z TAFS through 00Z Sunday evening/ Issued at 606 PM CDT Sat Jul 8 2017 VFR conditions will prevail through the period. While there may be an isolated thunderstorms this evening, confidence is low in this impacting any given terminal and have removed VCTS wording. The next chance for thunderstorms is Sunday afternoon over southeast Iowa, but have not mentioned at this time. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...FAB LONG TERM...Podrazik AVIATION...Ansorge
Area Forecast Discussion
National Weather Service Hastings NE
656 PM CDT Sat Jul 8 2017 .SHORT TERM...(This evening through Sunday) Issued at 252 PM CDT Sat Jul 8 2017 The main concern in the short-term is the potential for thunderstorms late this afternoon through the overnight. An ill-defined cold front/sfc trough is situated roughly from Lexington to O`Neil, NE. A weak perturbation aloft is also visible as an area of drying on the mid-level water vapor channel. Short-term models are in a bit better agreement that isolated to scattered showers/storms should begin to develop in this vicinity around 4PM, gradually shifting southward into the evening. The most robust convection should be west of a line from Central City to Red Cloud, where the RAP shows the highest corridor of instability along with ~30 kts of bulk shear. While not overly concerning from a severe weather perspective, there could be a few strong to marginally severe storms. Models quickly wrap up this activity by around 10PM, and most of the forecast area will likely remain dry, especially south of I-80. After midnight, a few additional showers or storms may redevelop east of Highway 281, where an area of isentropic upglide will persist through the overnight before gradually shifting to the east of the area by early tomorrow morning. Dry conditions should prevail through the day Sunday. The warmest stretch we`ve seen so far this summer begins tomorrow. Highs will reach the mid to upper 90s across most of central Nebraska and will approach 100 degrees in north-central Kansas. Because of relatively mild dewpoints (upper 50s to 60s), heat index values will "only" be in the upper 90s to around 100 degrees though. .LONG TERM...(Sunday night through Saturday) Issued at 252 PM CDT Sat Jul 8 2017 We will have to watch for a stray thunderstorm or two moving out of the Sandhills Sunday evening, but dry conditions are expected to prevail for now. The main story of the extended forecast is the impending heat wave. It still appears that Monday through Wednesday will be the warmest days, with highs in the upper 90s to low 100s for most of the area. Like Sunday, the humidity won`t be overly oppressive, so heat indices should max out in the low 100s each afternoon. We also may get some relief in the way of breezy southwest winds on Tuesday. Precipitation chances continue to be nebulous and a little difficult to pin-down as we transition to more zonal flow aloft. Superblend brings us the best chances for precipitation Tuesday night and again on Wednesday night. This seems reasonable given that the GFS brings weak upper-level waves through the area during these periods along with a favorable LLJ location. There are still no particularly strong signals for much of severe threat during the upcoming week, but given the time of year, we will continue to watch this closely. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday) Issued at 650 PM CDT Sat Jul 8 2017 Could be some TSRA activity around in the first hour or so, but support decreases rapidly. Bases should still be VFR, or mostly so. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Mangels LONG TERM...Mangels AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Wilmington NC
1124 PM EDT Sat Jul 8 2017 .SYNOPSIS... A weak cold front will stall across the area Sunday, enhancing the risk for thunderstorms and excessive rainfall. The front will slowly dissipate Monday and Tuesday as the Bermuda ridge builds back across the Carolinas. The Bermuda ridge and Piedmont trough will allow summertime heat and humidity to return, peaking Wednesday through Friday. A cold front will approach next Saturday. && .NEAR TERM /THROUGH SUNDAY/... As of 1130 PM Saturday...Except for the cell in Pender County, NC, convective activity is weakening as it approaches the coast. There is still quite a blast of west to northwest winds as the massed outflow of the last few hours worth of storms moves off the coast. Winds at both Myrtle Beach airports have gusted to 30+ mph with this outflow, which should also moves through the coastal Cape Fear area in the next 30-45 minutes. This appears to be our only wave of storms tonight, and I have sharply reduced PoPs behind this current activity as the atmosphere is stabilized back to the west. Discussion from 1000 PM follows... New storms have blossomed along I-95 from Florence northward across Dillon and Lumberton within the past hour. The activity south of Florence affecting Kingstree, Lake City, and the Brittons Neck region of Marion County should continue to produce the heaviest rainfall and the highest potential of severe weather over the next couple of hours as it pushes eastward toward the coast. Based on radar presentation, PoPs have been increased again to 60 percent along the Cape Fear coast, and to 70-100 percent along South Carolina`s Grand Strand beaches. Tonight`s severe weather risk will continue to be assisted by dry air aloft: model analyzed DCAPE values of 1000-1200 J/kg shows just how much negative buoyancy exists to strengthen convective downdrafts and produce strong, potentially damaging winds. Both the 23Z and 00Z HRRR initialized poorly with convection and were thrown out. It looks like the 18Z NAM (3 km) has the best depiction of storms and has become our model of choice. Discussion from 845 PM follows... A pair of vorticity maxes aloft plus a synoptic cold front moving into the area from the north will set the stage for a stormy night across eastern North and South Carolina. After another hot and humid day with temperatures in the 90s, the atmosphere remains quite unstable with surface- based CAPE still nearly around 2000 J/kg, and sufficient depth of moisture to allow convectively unstable parcels to originate from anywhere within a layer from the surface up through 6000 feet AGL. I have increased PoPs to 80-100 percent in a zone out ahead of the storms near Kingstree, SC as they move east-northeastward toward Conway, eventually sagging southeastward to cover most of Williamsburg, Georgetown, and Horry Counties through midnight. Over an inch of rain is forecast across this area as well, and I`ve added "heavy rain" to the forecast through midnight. I`m also closely watching an area of storms dropping southeastward through the NC Sandhills well out ahead of the actual surface cold front. High chance PoPs have been maintained here given what appears to be outflow possibly outrunning the convection and stabilizing the atmosphere at least temporarily. Storm organization should remain poor overnight as the main belt of strong mid-level winds remains well to our north. Boundaries will largely determine where storms track with virtually no change anticipated in steering flow. The 21Z and 22Z HRRR runs looked good, but the 23Z run did not initialize quite as well with the South Carolina convection. Little change has been made to overnight low temps, still expected to fall to 73-75 inland, and 75-78 near the coast. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 300 PM Saturday...The mid level pattern featuring troughing over the Ohio Valley and ridging out west will remain in place throuigh the short term period. If anything, the pattern weakens by Tuesday morning. The trough is not deep enough to push a cold front though the area and this front will dissipate slowly through the period. This will provide a focus for intervals of showers and thunderstorms. Some mid level drying may ease into the northwest zones late in the period hence the slightly lower pops in these areas at that time. Thermal profiles do show slight cooling for daytime highs Monday and depending on cloud cover some areas may struggle to reach the ninety degree mark. Overnight lows remain steamy however in the middle 70s. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 300 PM Saturday...A surface cold front will have dissipated across the area on Tue with the Bermuda ridge building back across the Carolinas mid and late week as the Piedmont trough sets up again. A cold front will approach the area next Saturday. A typical summertime pattern will be in place for much of the period. This means hit and miss showers and thunderstorms each afternoon and eve. A lingering mid-level trough Tue may help to enhance showers and thunderstorms. Then POPS will be trending higher with the approach of a cold front Sat and Sat night with several weak perturbations aloft helping to increase the coverage and longevity of convection. Highs will be warmest Wed through Fri, lower to mid 90s. Afternoon and early eve heat index values during this time will approach Heat Advisory criteria. Lows will be in the muggy 70s through the period. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... As of 00Z...Anticipate a mixture of VFR/MVFR through into Sunday afternoon with isolated periods of IFR as scattered showers and thunderstorms, and intermittent low cigs, move across the area ahead of an approaching cold front. With the cold front draped across the western portions of the Carolinas this evening, latest radar imagery depicts widespread SHRA/TSRA activity just to the southwest and around to the northwest, as a few showers are already moving into the forecast area. Expect increasing SHRA/TSRA chances tonight inland as the front moves closer, thus have carried VCTS at all terminals. Anticipate a lull in the activity towards the morning hours, with activity becoming widespread again as the frontal boundary stalls near the area. As a result, expect VCSH/VCTS with periods of MVFR/IFR to return and gusty variable winds on Sunday. Heavier downpours may reduce visibility temporarily at times. As for winds, gusty southwest winds may continue into the early overnight hours, before decreasing, with sustained winds around 10 kts. Into Sunday, winds will become variable and gusty at times. Extended Outlook...MVFR/IFR conditions are possible from thunderstorm activity, especially each afternoon and evening thru Wednesday. Flight restrictions will become longer in duration Sunday and Monday when thunderstorms are expected to be most numerous. && .MARINE... NEAR TERM /THROUGH SUNDAY/... As of 1130 PM Saturday...Showers and a few t-storms are moving offshore, preceded by a blast of northwest winds gusting as high as 25 knots. These offshore winds should veer back to the south and southwest by 1-2 AM as the synoptic wind gradually reestablishes itself. Discussion from 1000 PM follows... Models show the cold front currently sinking southward through the central Carolinas should stall before reaching the coast late tonight. Two large areas of thunderstorms, one across the NC Sandhills and another over the South Carolina Midlands, may act in concert to push a pulse of westerly winds out across the waters after midnight, but the actual front is expected to remain inland. These thunderstorms should reach the coastal waters later this evening with coverage ranging from 40 percent near Surf City to 80 percent near Myrtle Beach. Current observations show we are still experiencing winds near 20 knots from just east of the beaches all the way out to the Frying Pan Shoals buoy offshore, and these conditions are expected to persist until early Sunday morning. Seas are currently 3-4 feet nearshore, and a solid 4 feet offshore with some 5-footers possible near Frying Pan Shoals. SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 300 PM Saturday...No real surprises across the coastal waters through the period. Winds will remain from the south/southwest at 10- 15 knots. There may be an observation or two just eclipsing 15 knots overnight Sunday into Monday morning when the low level jet is diurnally enhanced but these should be short lived. Significant seas will remain 2-4 feet. LONG TERM /TUESDAY THROUGH THURSDAY/... As of 300 PM Saturday...A cold front will be dissipating upstream of the waters Tue as the Bermuda High rebuilds across the waters. The Bermuda High and Piedmont trough will act in unison to keep wind speeds in the range of 10 to 15 kt for much of the period and around 15 kt late Thu and Thu night. Seas will be mainly 2 to 3 ft, but building to a solid 3 ft later Thu and Thu night. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...SHK NEAR TERM...TRA SHORT TERM...SHK LONG TERM...RJD AVIATION...SGL
Area Forecast Discussion
National Weather Service Jacksonville FL
745 PM EDT Sat Jul 8 2017 .UPDATE...Early this evening...radar still showing band of scattered showers over Columbia and Gilchrist Counties...and areas of light rain over our far nrn counties in s-ctrl GA. Elsewhere precipitation has diminished. Have updated hourly POP/weather grids. Latest HRRR runs keep suggesting new convective development along boundaries after 00z...but think environment will stabilize enough after 00z to prevent anything more than isolated showers....covered by hourly 10 POPs. Low temp forecast Tonight looks fine. && .AVIATION...VFR next 24 hrs...except locally lower in afternoon TSRA Sunday. Included VCTS in TAFs after 19z Sunday for now. Next shift can look at 00z data to assess need for TEMPO group for TSRA in subsequent TAF issuances. && .MARINE...High pressure over the central Atlantic will drift northward over the next several days. A weak frontal boundary will approach the southeast Georgia/northeast Florida waters tonight and stall out across the area. This will keep increased chances for thunderstorms through Monday. Onshore flow will increase on Tuesday, with only isolated thunderstorms expected for the rest of next week. Rip Currents: Low risk Sunday. && .PRELIMINARY POINT TEMPS/POPS... AMG 74 93 74 92 / 30 60 40 70 SSI 78 89 78 88 / 20 50 40 60 JAX 75 92 76 91 / 10 60 30 70 SGJ 75 88 76 89 / 10 50 30 40 GNV 74 91 73 92 / 20 60 30 60 OCF 73 89 73 92 / 20 60 30 50 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ Wolf/Kennedy/Corless
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
624 PM CDT Sat Jul 8 2017 .UPDATE... Issued at 538 PM CDT Sat Jul 8 2017 The 18z MAV guidance came with 101 and 99 for highs at KVTN and KLBF Sunday. This guidance has been 2 or 3 degrees too cool lately. The deterministic 18z GFS has 104 and 102 for Sunday and a new forecast is in place using the GFS which is close to the HRRR EXP model. && .SHORT TERM...(This evening through Sunday) Issued at 236 PM CDT Sat Jul 8 2017 A weak surface low centered between Ainsworth and Broken Bow this afternoon will weaken this evening. Isolated to widely scattered thunderstorms will be possible this evening in the vicinity of the low, where weak surface convergence is noted along a couple of surface boundaries. Otherwise a mostly clear sky is expected with lows in the upper 50s and 60s. Hot weather is expected Sunday to the west of surface trough which will be located just east of the area. Mid to upper 90s are likely at most locations, along with drier air as dew points fall into the mid 40s to mid 50s as southwest winds advect drier air northeast across the area. Have removed all pops for Sunday as really no focus with surface trough to our east. .LONG TERM...(Sunday night through Saturday) Issued at 236 PM CDT Sat Jul 8 2017 Upper level high pressure centered across the southern Rockies, will slowly drift north and be centered across the central Rockies by weeks end. This keeps flow aloft mostly northwest through the period. Gradually rising heights aloft through the week will keep thunderstorm chances low, but not zero. Subtle waves within northwest flow will have to be evaluated on a daily basis to see where and when a few thunderstorms could develop. Otherwise very hot week in store, with GFS ensemble indicating highs potentially around 100 give or take a few degrees through the entire upcoming week. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 624 PM CDT Sat Jul 8 2017 VFR is generally expected all areas overnight through 22z Sunday. A stray thunderstorm or two may form this evening. The area of concern is a frontal boundary stretching from Stockville to Brewster to Burwell. The boundary is expected to translate east this evening with thunderstorm chances ending around 03z. A dryline bulge shown in the NAM and HRRR EXP may spark a few thunderstorms Sunday afternoon. The area of concern is generally Along and east of a line from KBBW-KANW-KVTN. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...CDC SHORT TERM...Taylor LONG TERM...Taylor AVIATION...CDC
Area Forecast Discussion
National Weather Service Miami FL
811 PM EDT Sat Jul 8 2017 .UPDATE... Similar to yesterday evening, the convection continues to diminish across the peninsula with the loss of diurnal heating. Winds are expected to become light and variable overnight in the interior with light southeast winds persisting along the east coast. Short term model guidance generate a few showers with possibly some embedded thunderstorms developing during the late night over the Atlantic, then advect these storms towards the east coast by early Sunday morning. These showers should diminish quickly as they move inland. Thus, in the update, decreased PoPs over the interior tonight. Otherwise, besides loading in the latest short term wind guidance, all other variables appeared on track. && .PREV DISCUSSION... /issued 742 PM EDT Sat Jul 8 2017/ AVIATION... VFR expected to prevail at all terminals tonight and through Sunday morning, along with mainly light and variable winds. Another round of afternoon thunderstorms may bring periods of MVFR cigs/vis, especially over APF. Some outflow boundaries could produce brief periods of strong and variable gusty winds. PREV DISCUSSION... /issued 414 PM EDT Sat Jul 8 2017/ DISCUSSION... Latest IR imagery from this afternoon shows broad troughing over the Tennessee Valley and an elongated upper level high pressure ridge over the Western Atlantic waters, near Bermuda. The flow pattern into South Florida is from the south southeast, with the region currently sandwiched between the influence of the Bermuda high and a weak upper level low in the eastern Gulf. The latter feature in the Gulf has allowed for 500 mb to lower slightly, down to around -7.0 C (which is average or slightly below for this time of year). Similar to the last couple of days, convection is concentrated over the interior and Gulf coast. This activity continues to propagate in various directions, based on colliding outflow boundaries. The strongest storms so far today have produced wind gusts mainly in the 30 mph range with brief heavy rain and frequent lightning. Short term models, such as the HRRR and Hi-Res WRF, prog this activity to maintain over the peninsula, including portions of the east coast metro, through early this evening, then diminish with the loss of diurnal heating. Wind will become light and variable over the interior tonight with southeast winds 5 to 10 mph persisting along the east coast metro region. Showers with an occasional embedded thunderstorm may develop once again over the Atlantic waters and drift towards the eastern portion of the peninsula by early Sunday morning. Sunday through mid next week: Little changes synoptically on Sunday, leading to a very similar weather pattern as today. Expect light southeasterly flow with both the east and west coast sea breezes developing. Thunderstorms generated off of this boundary will propagate in random directions, based on the local effects of the outflow boundaries and their collisions. The main threat threat with the storms will again be frequent lightning, brief heavy rain, and gusty/erratic winds. GFS forecast PWATs drop to between 1.50"-1.75", so this may translate to slightly less afternoon convection. With high pressure dominating near Bermuda from early to mid week, rounds of increased moisture will advect over the peninsula from the southeast through the period. The arrival of deeper atmospheric moisture may lead to increase of shower/storm coverage by Wednesday/Thursday. Maximum temperatures through the period will remain around 90 degrees with low temperatures in the mid 70s in the interior to near 80 along the east coast metro. These values near normal for this time of year. MARINE... Prevailing east-southeast winds around 10 knots will continue across the South Florida waters through Sunday as high pressure remains to the north of the region. Both the Gulf and Atlantic seabreezes are expected to develop each afternoon, leading to locally higher winds near the coast. Isolated to scattered showers and thunderstorms are possible each day, with locally higher winds and seas as well as lightning near any thunderstorms. AVIATION... The next few hours will be dominated by weak synoptic flow, and shifting wind directions due to thunderstorm outflow boundaries. Thunderstorms are expected to migrate inland and away from east coast terminals by 20Z. APF could see some storms during the afternoon. Terminals should remain VFR but brief MVFR is possible during any strong thunderstorms. Storms and winds calm down for the overnight hours. A similar pattern is expected for tomorrow in terms of shower/thunderstorm timing for east coast terminals. && .PRELIMINARY POINT TEMPS/POPS... West Palm Beach 77 91 79 90 / 30 30 30 40 Fort Lauderdale 79 89 80 89 / 30 30 40 40 Miami 78 90 79 90 / 30 30 50 40 Naples 75 90 76 92 / 20 50 30 50 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. GM...None. && DISCUSSION...27/JT MARINE...27/JT AVIATION...17/AR
Area Forecast Discussion
National Weather Service Norman OK
1052 PM CDT Sat Jul 8 2017 .UPDATE... Adjusted precipitation chances and temperatures. && .DISCUSSION... Increased and added precip chances to portions of western north Texas to account for the ongoing, yet weakening, convection persisting across Texoma. Removed chances after 2 AM CST from Oklahoma and Texas as overall conditions continue to be unfavorable for development. Looking up stream, in western Kansas, not much in the way of convective activity. Instability will continue to wane through the overnight and with a lack of forcing, not expecting much in the way of precipitation. The latest HRRR has bought into this trend, backing way off on development, the RAP, to a lesser extent, concurs. Really, based off going conditions and trends, feel confident to drop categorical precipitation chances for the early morning hours across the region. Kurtz && .PREV DISCUSSION... /issued 1026 PM CDT Sat Jul 8 2017/ DISCUSSION... AVIATION... Scattered rain and thunderstorms over the southern third of Oklahoma will dissipate before sunrise. South winds and VFR conditions are expected apart from thunderstorms. PREV DISCUSSION... /issued 648 PM CDT Sat Jul 8 2017/ DISCUSSION... AVIATION... Scattered rain and thunderstorms over the southern half of Oklahoma will dissipate before midnight. South winds and VFR conditions are expected apart from thunderstorms. PREV DISCUSSION... /issued 240 PM CDT Sat Jul 8 2017/ DISCUSSION... A MCV continues to produce elevated showers NW of OKC this afternoon. Looking at visible imagery and surface observations, it appears this feature will interact with a remnant boundary near the I40 corridor through early this evening. A few of the storms could become severe before sunset (mainly wind threat) near and south of OKC where heating hasn`t been as inhibited by cirrostratus. Most of this activity should wane as it moves SE after dark. Additional chances will return late tonight through early Sunday morning, mainly over southern OK, as a weak mid level shortwave trough progresses southward. Isolated, diurnal development will then be possible along and south of I40 during the afternoon and evening Sunday. Rain chances will likely drop significantly by Mon as heights increase with an expanding upper ridge from the west. A few showers and storms may be possible on its southern/SE periphery Tue as a mid to upper trough slides westward over central TX. Otherwise, expect a drying trend with regards to precip through most of the week as the upper ridge expands over the central CONUS. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 70 94 73 96 / 20 20 10 10 Hobart OK 72 98 74 97 / 10 20 10 0 Wichita Falls TX 74 98 74 97 / 40 20 20 10 Gage OK 68 98 72 100 / 10 10 10 0 Ponca City OK 71 95 73 95 / 10 10 10 0 Durant OK 72 91 73 94 / 30 30 20 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ 04/09
Area Forecast Discussion
National Weather Service Pueblo CO
313 PM MDT Sat Jul 8 2017 .SHORT TERM...(This evening through Sunday) Issued at 313 PM MDT Sat Jul 8 2017 Isolated to scattered -tsra have developed over the mountains at mid- afternoon, with a few storms moving out across El Paso county as well. While instability looks plentiful (CAPEs 1000-1500 J/KG), shear is rather weak (0-6km 20-30 kts), suggesting most storms will stay sub-severe into the evening. Latest HRRR is considerably more aggressive building storms eastward across the plains this evening, as convective outflows may serve to consolidate convection east of I- 25. Will boost pops over the plains to account for this possibility, with most storms then ending in the 03z-06z time frame. On Sun, pocket of drier air will rotate southward across CO, leading to a downturn in convection, especially over the I-25 corridor and on the plains. Mountains will see isolated to scattered storms once again, though drier low levels suggest precip amounts will be rather light most areas. Max temps will begin to climb as mid level temps rise, leading to mid/upper 90s reappearing on the plains by late afternoon. .LONG TERM...(Sunday night through Saturday) Issued at 313 PM MDT Sat Jul 8 2017 Extended models are in fairly good agreement on keeping high pressure in some form across the region through the long term, with mainly diurnal convection in play. Expect scattered to likely convection over the higher terrain each aftn and eve, and isolated to low-end scattered pops across the eastern plains. Sunday night through Tuesday...A relatively flat ridge of high pressure will remain across the region, stretching from the Great Basin to the central US plains. Both Mon and Tue will be very hot days, the hottest of the extended period, with max temps in the mid to upper 80s for the high valleys, and 90s to around 100F for the eastern plains. Any storms that form over the mts during the aftn hours will likely be slow to move, and area burn scars will need to be monitored for heavier rainfall amounts. Wednesday through Saturday...Models agree on the upper ridge amplifying once again and edging to the west, though the GFS is much farther west with the location of the ridge axis. The GFS places the ridge axis along the UT/CO state line, while the EC places the axis over CO. Continued diurnal convection is expected, though the storms will probably move a bit faster off of the higher terrain once they form. Temps will remain hot, though with about 5 degrees of cooling should be more seasonal in nature. Look for max temps in the 80s for the high valleys, and mid 80s to mid 90s for the eastern plains. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 313 PM MDT Sat Jul 8 2017 Scattered tsra will persist into this evening across the area, and will continue with vcts at all taf sites until 02z-03z. With increased moisture, cloud bases and vis with any storms will likely be lower than yesterday, with brief MVFR or even IFR under the strongest storms. Storms then end 03z-06z, with clearing skies and VFR conditions overnight and through the first half of Sun. Isolated -tsra will develop over the mountains 17z-18z Mon, though drier air moving south through state will keep storms weak and tied mainly to higher terrain through the afternoon. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PETERSEN LONG TERM...MOORE AVIATION...PETERSEN
Area Forecast Discussion
National Weather Service Las Vegas NV
648 PM PDT Sat Jul 8 2017 .SYNOPSIS...The first significant push of monsoon moisture is expected to bring expanding thunderstorm chances to the area over the next few days. With the increasing moisture and cloud debris, daytime temperatures for Sunday and Monday are expected to be cooler before most of the area gradually warms up and drys out Tuesday onward. && .UPDATE...Scattered thunderstorms extending from Dolan Springs to south of Wikieup are slowly moving to west and are expected to move over the Colorado River Valley over the next couple of hours. The latest HRRR supports tstorm activity from this line moving to eastern San Bernardino County before diminishing. Expanded thunderstorm chances further west to account for this. -Salmen && PREVIOUS DISCUSSION...253 PM PDT... .SHORT TERM...through Monday night. Thunderstorm activity will be on the increase through Monday as monsoon moisture pushes into the area from Arizona. Precipitable water values greater than an inch currently encompass much of the SE CWA and are forecast to expand to much of the southern half of the area on Sunday and Monday. A juicer airmass is on our southern doorstep with surface dewpoint temperatures in the 50-60 degree range. A large thunderstorm complex over south central Arizona this afternoon is moving westward with the general 850-700MB flow directing it towards our area. The latest HRRR surface wind analysis and forecast suggests outflow winds from this activity as well as other convection over central Arizona reaching the eastern Mohave County border late this afternoon and spreading west into Clark County this evening. In addition, the HRRR brings thunderstorm outflow winds to Lincoln and Clark counties from storm activity over southwestern Utah which could bring storm activity to the Las Vegas Valley later this evening. All and all, it should be interesting to see how this all plays out. .LONG TERM...Tuesday through Saturday. Upper high shifts further east into the central states Tuesday- Thursday allowing southwest flow associated with Pacific Northwest trough to bring a drier/more stable air mass to parts of the region. The probability of thunderstorms decrease Tuesday-Thursday across San Bernardino County and southern Nevada, more so across Mohave County Wednesday and Thursday. The troughing influence will allow for a slight chances of thunderstorms across northern portions of Inyo and Esmeralda Counties. The models show the high center shifting west becoming established once again over northern Utah Friday/Saturday. Easterly flow south of the high center combined with an inverted trough over northwest Mexico should have low level moisture pushing back west into Mohave County by next weekend. Near to slightly above normal temperatures early-midweek will begin to rise late week. Tropical Storm Eugene in the eastern Pacific is forecast to become a Hurricane Sunday. Then Hurricane Eugene will move northwest well away from the Baja Peninsula through Monday before dissipating in colder waters by Wednesday. None of the models at this time show any injection of moisture into the region from Eugene but its something we`ll be monitoring closely. Temperatures will be around normal Tuesday through Thursday, but will once again warm to around 5-7 degrees above normal by Friday as the high rebuilds back to the west. && .AVIATION...For McCarran...Gusty outflow winds will impact the airport early this evening. South winds around 20-30 kts are likely with the initial outflow boundary late this afternoon, but its possible that a second outflow boundary from Arizona will impact the terminal early this evening. Models are indicating the potential for southeast winds 20-30 kts occurring between 01-03z this evening. If they occur they would likely last through 04-05z before shifting back to the southwest with speeds around 10 kts overnight. Thunderstorms are likely to be more scattered Sunday with gusty and erratic outflow winds impacting the terminal at times during the afternoon and early evening. No operationally significant ceilings are forecast, but localized turbulence and icing hazards can be expected with any shower/thunderstorm activity. For the rest of southern Nevada, northwest Arizona and southeast California...Generally light winds following typical summertime diurnal trends expected at most terminals once again, outside of thunderstorm influences. Thunderstorms are possible once late this afternoon and evening, mainly focused on higher terrain, with low chances of impacting the terminals. Gustier winds are possible by the evening, especially east of a DAG-LAS-CDC line where consolidated thunderstorm outflow looks likely. Isolated to scattered thunderstorms are forecast Sunday with slightly better coverage. Gusty outflow winds will be the main impact, but brief heavy rain will be possible. && .FIRE WEATHER...Monsoon moisture will bring an increase in lightning activity to the area over the next few days with the initial round of storm activity possibly dropping very little rain resulting in an increasing potential for new fire starts. As moisture increases and deepens, there will be better chances for wetting rains from thunderstorms. A drying and warming trend will commence by Tuesday through the end of the week. && .HYDROLOGY...Isolated thunderstorms over the eastern Sierra over the next few days may aid snowmelt runoff and keep some drainages elevated with ongoing minor flooding possible. Remember, never drive through flooded roadways or around barricades. Also, pastureland or farmland adjacent to creeks, streams or rivers could experience areas of standing water. && .SPOTTER INFORMATION STATEMENT...Increasing monsoonal moisture will lead to increasing thunderstorm chances and cooler temperatures Sunday and Monday. Conditions are not currently forecast to be favorable for widespread flash flooding risks, however, spotters are always encouraged to report significant rainfall amounts as well as any reports of damage or flooding. && $$ Short Term...Salmen Long Term/Aviation...Gorelow For more forecast information...see us on our webpage: or follow us on Facebook and Twitter