Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/07/17

Area Forecast Discussion
National Weather Service Wakefield VA
913 PM EDT Sun Aug 6 2017 .SYNOPSIS... High pressure will push farther off the Mid Atlantic coast as low pressure tracks northeast from the lower Mississippi Valley. A warm front will lift into the local area Monday morning, with a trailing cold front pushing through the region Monday night. This front stalls over North Carolina Tuesday into Wednesday as high pressure builds north of the area. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Latest analysis indicating that sfc high pressure has moved offshore with sfc low pressure centered over NW TN/SW KY and tracking ENE. A sfc trough extends E into NC from the parent low with an associated sfc warm front now across central NC. A Isolated tstms that were not too far S of Bertie Co have now diminished, while main bands of more widespread tstms are confined to the SC coastal Plain. Overall, looks like little forcing through midnight so have removed PoPs through the next few hrs. Latest RAP as well as the 18Z NAM is picking up on developing clouds/increasing WAA aloft over north central NC/south central VA, but is probably a bit overdone later tonight spreading too much in the way of QPF into the AKQ CWA as some of this may go into clouds. Still can`t rule out at least isolated/scattered showers after midnight and will have PoPs gradually expanding to the N and near 40% to 50% over the N/NW and ~20% for the SE coastal zones. This will be mainly just showers as sfc-based CAPE will be limited (especially N), though did include slight chance tstms S after 06Z as there is significant 800-900 mb WAA/and resulting negative showalter indices spreading N. Low temperatures tonight will be mostly in the upper 60s to lower 70s. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Nearly zonal mid/upper level flow Mon. S/W trough will be tracking across the nrn mid- Atlantic region Mon. A weak surface low tracks ENE from KY/TN early Mon...which lifts a warm front across the area (accompanied by SHRAs). The associated cold front then approaches from the NW Mon aftn/evening as the surface low pushes toward the NJ coast. Moisture continues to increase Mon morning. PoPs ramp up to likely (60-70%) Mon morning across mainly nrn-wrn half of the local area during the morning...then 60-80% for the entire area Mon afternoon. There will be a chc of tstms during the afternoon/evening...but the intensity likely to be limited...esp away from SE VA-NE NC (where there may be potential for better instability due to periods of sun in the morning). Most of the FA will have clouds/SHRAs and rather poor lapse rates Mon despite decent deep layer shear. Highs in the u70s-l80s N and central locations...m80s SE. Low pressure exits off the srn New England coast later Mon night with the associated cold front reaching the VA/NC border by 12z Tue. The front then settles across NC by Tue aftn. PoPs remain 40-70% Mon night (highest SE)...locally heavy rainfall possible. At least partial clearing is expected across the N Tuesday as hi pres builds across PA/MD. Clouds and a 30-50% chc of showers will persist across far srn VA/NE NC in closer proximity to the boundary. Highs Tue will mainly be in the upper 70s to low 80s...after morning lows in the u60s N to 70-75F S. Frontal boundary remains S of the FA Tue night into Wed. How much drying/clearing occurs across the (srn) portion of the FA uncertain. Maintaining low PoPs (15-30%) near-S of the VA-NC border for now. Otherwise...partly sunny N...VRB clouds-mostly cloudy S. Lows Tue night 60-65F N and 65-70% S. Highs Wed mainly 80-85F. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Long term period will feature slightly below normal or near normal temps and decent chances for rain, esply Thu thru Sun. A frontal boundary acrs the Carolinas Wed night, will slowly lift back north and into/acrs the region Thu thru Sat, then low pressure and a cold front will approach fm the west Sun into Sun night. Highs will be in the lower 80s Thu and Fri, in the lower to mid 80s Sat, and in the mid to upper 80s Sun. Lows will range fm the mid 60s to mid 70s. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... VFR conditions to prevail through 06Z, with deteriorating conditions thereafter as a warm front begins to lift through the region with lowering/thickening clouds and a chance for some showers. Looks like higher chances for IFR conditions through 12Z would be from RIC and points N/NW, with Cigs likely to stay 3,000-5,000 ft at the other TAF sites. Showers and embedded tstms are likely to overspread the area on Mon. Periodic MVFR conditions are expected with occasional IFR conditions (in Cigs N and in VSBYS w/ heavier showers/tstms all areas). The associated cold front drops through the area Mon night maintaining a chc for SHRAs and degraded flight conditions. The front stalls S of the region Tue-Wed as hi pres builds N of the area. A chc of showers (30-60%) will continue from ORF to ECG Tuesday...w/ the potential diminishing the 15-25% by Wed. Another low pressure system potentially impacts the area late in the upcoming week. && .MARINE... Latest surface analysis has a high pressure centered just off the coast. Obs indicate southeast winds of 10-15 knots over the waters with waves of 1-2 feet and seas of 2-3 feet. Expecting a slight uptick in winds, occasional gusts up to 20 knots across the Bay, this evening and overnight as pressure gradient strengths ahead of an approaching low pressure system. The flow becomes southerly, 10- 15 knots, on Monday as the surface low lifts into the Mid-Atlantic region. Waves build to 1-3 feet and seas 2-4 feet. Expecting an uptick in winds Monday evening due to modest pressure falls and an approaching cold front. Went ahead and put up a SCA for the Bay and Ocean zones for Monday evening into early Tuesday, primarily for gusts up to 25 knots. Winds become northwest behind the front on Tuesday morning. Wind speeds are expected to remain at or below 15 knots Tuesday with waves 2-3 feet and seas 2-4 feet. The front stalls south of the region over the Carolinas Tuesday and Wednesday as high pressure builds over the Northeast. Light E/NE flow is expected for the first portion of the extended period. The frontal boundary lifts back north of the region by the end of the week shifting winds to the south. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory from 4 PM Monday to 7 AM EDT Tuesday for ANZ630>632-634. Small Craft Advisory from 7 PM Monday to 7 AM EDT Tuesday for ANZ633-654-656-658. Small Craft Advisory from 4 PM Monday to 4 AM EDT Tuesday for ANZ650-652. && $$ SYNOPSIS...ALB NEAR TERM...ALB/LKB SHORT TERM...AJZ/ALB LONG TERM...TMG AVIATION...LKB MARINE...AJB
Area Forecast Discussion
National Weather Service Albany NY
1002 PM EDT Sun Aug 6 2017 .SYNOPSIS... High pressure will move east of the Mid Atlantic Coast tonight with clouds increasing from the south and west after midnight. A warm front associated with low pressure moving towards the Ohio Valley tomorrow morning will bring some rainfall into eastern New York and western New England. The low pressure system will pass south of Long Island Monday night with the rainfall ending by Tuesday morning with fairer and drier weather returning for the mid week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... A couple of changes to the forecast for this update. Clear skies in place across much of the CWA with calm winds. Two implications...temperatures outside of urban areas have dropped and are below trends and in some cases approaching overnight lows. I have lowered min temps for those locales in rural areas. Placed lows around 2am given expectation of clouds moving in ahead of next system. Have also introduced patchy fog into the forecast as well. An area of showers/thunderstorms continues to track across Lake Ontario perhaps associated with upper level speed max. HRRR shows some evidence of SHRA/TSRA across northern tier tonight. High clouds will continue to increase after midnight well in advance of the warm front over the Ohio Valley and Mid Atlantic Region, as the sfc high moves offshore. Low pressure associated with the warm front will be moving from the central Plains into central MS River Valley by sunrise. The NAM/GFS/ECMWF/CAN GGEM are all in pretty good agreement slowing down the leading edge of the warm advection light rainfall until more towards daybreak especially south and west of the Capital Region. We introduce slight and low chc pops of very light rainfall with the thickening and lower clouds, as it will take a little time for the column to moisten based on the NAM/GFS model soundings. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... Tomorrow...A positively tilted upper level trough will be approaching the Northeast from the Great Lakes Region and southeast Canada. A short-wave in the northern stream will be approaching the St Lawrence River Valle and eastern Great Lakes Region during the afternoon. Further south, a southern stream short-wave will be approaching from the central MS River Valley and the TN Valley. These short-waves will attempt to phase near Long Island and the southern New England Coast by Mon night. In the meantime, some warm advection or isentropic lift increases ahead of a weak disturbance in the southwest flow ahead of the warm front. The NAM looks to be suffering with some convective feedback and is over doing the QPF. The GFS/ECMWF and GEFS show an increasing southerly low level jet 30-35 kts or so advecting moisture into the forecast area especially for locations from the Capital Region south and east during the late morning into the afternoon. The GEFS have a southerly wind anomaly /+v-component of the wind of 1 to 2+ standard deviations above normal/. The PWATs increase to 1-2 standard deviations above normal especially for the southeast Catskills/Mid-Hudson Valley and NW CT. The best low-level baroclinic zone looks like it will impact the Capital Region/Northern Catskills/southern VT south and east with periods of light to moderate rainfall. This portion of the forecast area will be near the right entrance region of a 100-125 kt H250 jet streak. The isentropic lift will be enhanced by the jet dynamics. There could be a sharp cutoff in the rainfall based on the ECMWF/GFS trends. The Canadian GGEM and NAM are further north with the QPF. Again, we are leaning closer to the GFS/ECMWF/GEFS mean and WPC placement and position with the movement of the sfc low near the MD/PA border during the day and reaching s-cntrl NJ by early evening. It should be noted further north, the northern stream short-wave will likely kick off a few showers and isolated thunderstorms that may graze the western Adirondacks. There are small amounts of MUCAPE of 500 J/kg or less, and we did include a slight chc of thunder there, and also closer to the sfc low passing to the south where MUCAPEs are 300 J/kg or less near the mid-Hudson Valley, southeast Catskills, and NW CT. Likely and categorical POPS were used across the forecast area during the day with cool and damp conditions. Highs will be mainly in the mid and upper 60s in the valley areas, and upper 50s to mid 60s over the hills and mtns. Mon night....Periods of rain continue with some moderate to briefly heavy rainfall from the Capital Region south and east, as the sfc low passes south of Long Island and then lifts north and east towards Cape Cod. The heaviest rainfall looks to be suppressed to our southern most zones. There continues to be good synoptic ascent in the northwest quadrant of the cyclone and its mid and upper deformation zone. A slight chc of thunderstorms was kept in the early evening for the southeast Catskills, mid Hudson Valley, southern Taconics, and NW CT with weak elevated instability. The rain should taper to showers after midnight. Lows will be in the 50s. Overall, Mon-Mon night we are expecting a quarter to half inch of rainfall north and west of the Capital Region with a half an inch to an inch and a half from southern VT, the Capital Region, and the eastern Catskills south and east. The heaviest totals maybe in the southeast Catskills, mid-Hudson Valley and NW CT. Tuesday...The upper level trough and its associated short-wave energy still needs to move across the region, as the sfc cyclone moves toward Nova Scotia. A slight chance of showers was kept in the forecast from Albany north and east. Cool and breezy conditions will occur in the wake of the trough passage, as H850 temps will be in the +10C to +13C range. Clouds in the morning will give way to partly sunny conditions with highs generally in the mid and upper 70s across the lower elevations, and mid 60s to lower 70s over the hills and mountains. Tuesday night...High pressure ridges in from the Midwest and lower Great Lakes Region with cool and dry conditions. Humidity levels will continue to be comfortable for August. Lows will be in the mid 40s to around 50F over the higher terrain, and lower to mid 50s in the valleys. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... In the mean, broad troughing dominates the eastern two thirds of the USA. Starting out, high pressure is in control for Wednesday and Thursday. Generally dry conditions are expected. There is a frontal boundary to the north of the CWA in the picture during at this time. So have low chance pops for northern zones. High pressure tracking across southern Canada on Friday nudges the boundary into the northern CWA bringing chances of showers and thunderstorms. Next weekend,an upper level disturbance transiting the region along with weak surface low pressure brings an increasing chance of showers and thunderstorms. Despite frequent mention of showers and thunderstorms in the discussion, expect a reasonable amount of clear/partly cloudy skies through the period. Temperatures through the period will average near normal. Highs in the 70s to low 80s, and lows in the 50s to low 60s. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... VFR condition tonight will give way to MVFR most terminals on Monday. As a system in the Southern Plains heads northeast, clouds will be on the increase tonight yielding a solid overcast by early morning. Rain associated with this system will approach the area as well. Models indicate somewhat slower precipitation arrival time on Monday, so pushed back RA onset by a few hours at all terminals from 18Z TAFs. Rain should overspread all terminals by early afternoon. Expect all terminals to drop to MVFR conditions in the rain. Exception would be KGFL where only light rain will allow VFR conditions to hold. Another possible exception could KPOU where IFR conditions are possible Monday afternoon. Not enough conviction to place IFR in KPOU TAF now. Outlook... Monday Night: High Operational Impact. Definite SHRA...RA. Tuesday: Slight Chance of SHRA. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: Low Operational Impact. Slight Chance of SHRA...TSRA. && .FIRE WEATHER... High pressure will move east of the Mid Atlantic Coast tonight with clouds increasing from the south and west after midnight. A warm front associated with low pressure moving towards the Ohio Valley tomorrow morning will bring some rainfall into eastern New York and western New England. The low pressure system will pass south of Long Island Monday night with the rainfall ending by Tuesday morning. High pressure returns with dry weather for the mid week. The RH values will increase to 80 to 100 percent Monday morning with rainfall moving into the region. The RH values will remain high during the day in the 65 to 85 percent range. Expect the RH values to be around 100 percent Tuesday night. The winds will become light from the south to southeast at 5 mph or less tonight. Expect south to southeast winds at 5 to 15 mph on Monday, and the winds to shift to the north to northwest at 5 to 15 mph Tuesday morning. A widespread soaking rainfall is expected tomorrow into tomorrow night. && .HYDROLOGY... Dry weather will be over the hydro service area today into most of tonight. A widespread soaking rainfall is expected Monday through Monday night with total rainfall a half an inch to an inch and a half from the Capital Region, southern Vermont, and the eastern Catskills south and east across the Hydro Service Area. A quarter of an inch to a half an inch is possible over the northern most basins. A shift further southward with the sfc wave would lower these rainfall amounts even more. This is expected to be a longer duration rain event for the ground to absorb in the rainfall, and no widespread hydro problems are anticipated at this time. The latest MMEFS guidance shows no problems on the main stem rivers. Some minor within banks rises are expected on the main stem rivers. Some ponding of water and poor drainage flooding is possible on roadways with any heavier bursts of rain especially across Ulster, Dutchess, and Litchfield Counties. Drier weather returns Tuesday afternoon through the mid-week, which allows flows to recede. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Wasula NEAR TERM...OKeefe/Wasula SHORT TERM...Wasula LONG TERM...OKeefe AVIATION...OKeefe FIRE WEATHER...Wasula HYDROLOGY...Wasula
Area Forecast Discussion
National Weather Service Denver/Boulder CO
817 PM MDT Sun Aug 6 2017 .UPDATE... Issued at 802 PM MDT Sun Aug 6 2017 Nern CO is in the right exit rgn of an upper level jet which has been helping produce sct showers and storms mainly along and north of a Greeley to Akron line. Meanwhile there is a bndry moving slowly wsw fm wrn Nebraska which will eventually move into the front range urban corridor by midnight. Hi res data hasn`t been doing a good job with pcpn coverage so far thus have little confidence in pcpn trends the rest of the night. If the right exit rgn of the upper level jet stays in the same general area then the nern plains would have the best chc of additional pcpn thru midnight. && .SHORT TERM...(This evening through Monday) Issued at 340 PM MDT Sun Aug 6 2017 Anticyclonic upslope flow east of the mountains will continue to moisten the high plains airmass next 12-24 hours. In the short term, the extensive low/mid-level cloud cover generated by this flow is largely to blame for the lack of showers/t-storms on the plains today. Within the past 90 minutes isolated t-storms have begun to pop over the higher terrain largely devoid of cloud cover, with their motions principally easterly. With the unseasonably cool, stable air blanketing the plains, the initial wave of storms moving of the Front Range are likely to fall apart. One exception to this would be in the vicinity of the Palmer Divide where skies cleared long enough today to adequately destabilize the boundary layer. T- storms moving off the Tarryall Mtns and srn foothills of Park and Jefferson counties will have the produce to produce at least dime size hail, up to a half inch of rain in under 30 mins and wind gusts to 40 mph as they move out over the Palmer Divide during the next 2-4 hours. Attention turns north this evening with a push of moist northeasterly winds from the Nebraska panhandle. This surge may be all that`s necessary to punch through the sfc based cap on the plains. High res models show this happening around mid-evening with quick development of scattered t-storms and numerous showers as this boundary slides south towards the metro area. HRRR and ARW pretty optimistic with precip amounts from these storms, anywhere from 0.25 to 0.75 inch in an hour`s time. Should these amounts actually materialize, some areas could see some flooding, esply on soils already soaked by yesterday`s rainfall. This bares watching even though the heavy rainfall is not expected to be widespread. Late tonight, models show this precip winding down. I`m not convinced this will occur with continued orographic forcing, but additional rain amounts should drop off considerably during the pre-dawn hours. Towards morning, could see patchy dense fog esply up around Greeley, Ft. Collins and Loveland. Meanwhile in the high country, isolated to scattered t-storms should dissipate not too long after sunset without any sustained forcing aloft. On Monday...the high plains airmass should continue to moisten and with extensive cloud cover, temperatures will struggle to rise more than 10-12 degs above their expected overnight lows. Models show a relatively strong upslope gradient in place for most of the day, and and an east-southeast low-level flow. The bulk of the precipitation tomorrow is likely to be concentrated over and along the Front Range foothills, particularly during the afternoon as it now looks. By late afternoon could see locally heavy rainfall over and near the higher terrain south and west of Denver. Could see isolated storms in this area depositing 1-2 inches of rain in an hour`s time. This bares watching, particularly should this fall on burn scars in the area. For the high country, shower/t-storm chances look better tomorrow as a couple of weak disturbances in west-northwest flow aloft passing over the area. .LONG TERM...(Monday night through Sunday) Issued at 340 PM MDT Sun Aug 6 2017 An upper level trough embedded in the west-northwest flow aloft will track across Colorado Monday night. Lift from the wave and an easterly low level flow ahead of it is expected to produce an area of rain with a few embedded thunderstorms. This activity will shift east across the area with rain ending west to east Monday night and Tuesday. Precipitable water values will be above an inch along the Front Range and across the eastern plains. Locally heavy rainfall will be possible, mainly under stronger storms that form. Models continue to show widespread rainfall totals of a half inch to 2 inches with a few areas around 3 inches tonight through Tuesday morning. Fortunately, the rainfall is expected to be spread out over 1 to 2 days. Localized flooding could become an issue under the heavier storms where rainfall amounts near 3 inches. Drying will occur Tuesday morning due to subsidence behind the exiting system. Airmass becomes unstable during the afternoon with scattered showers and storms expected over the higher terrain. Because of the cool and stable airmass over the plains, storms may have trouble surviving off the higher terrain. Temperatures will be cool again Tuesday with readings in the 70s. For Wednesday through Sunday, upper level ridge axis sets up just west of Colorado, from the Four Corners to the Great Basin. This will keep a west to northwest flow aloft over Colorado. Appears there will be enough moisture and instability for scattered showers and thunderstorms each day. Best chance should be over the higher terrain. Not seeing any embedded troughs to increase precipitation chances, so will stick with scattered pops. Temperatures are expected to stay below normal with highs in the upper 70s to lower 80s. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 802 PM MDT Sun Aug 6 2017 Pcpn has been staying to the north and northeast of DIA so far this evening. A few storms have developed nr Greeley and are moving se but they may stay north of DIA. There is a bndry move wsw fm wrn Nebraska which will eventually move in around midnight. Thus should gradually see lower ceilings dvlp overnight with stratus deck blo 3000 ft by 09z and 1500 ft by 12z. Winds should remain mainly ene overnight. && .HYDROLOGY... Issued at 340 PM MDT Sun Aug 6 2017 Two periods of concern...this evening and tomorrow afternoon. Areas of concern...areas in and near the foothills southwest of Denver and along the Palmer Divide. Slow moving storms training over soils already saturated by rainfall yesterday, could result in localized flooding. Of most concern would be burn scars in this area. Rainfall amounts up to an inch per hour are possible in this area this evening, and from 1-2 inches per hour tomorrow afternoon. It does not appear that this heavy rainfall threat will be widespread, so no flash flood watch at this time. But, this does bare watching during the next 12-18 hours. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...RPK SHORT TERM...Baker LONG TERM...Meier AVIATION...RPK HYDROLOGY...Baker
Area Forecast Discussion...Updated
National Weather Service Billings MT
856 PM MDT Sun Aug 6 2017 .UPDATE... No significant updates to the forecast this evening. BT && .SHORT TERM...valid for Mon and Tue... Northwest flow aloft exists over the region, with a shortwave dropping through eastern MT. Off and on showers/isold TS has been occurring for awhile in our far east, where temps are still only in the mid 60s. Conditions to the west have been dry, though at 230 pm there was some shower activity coming off the Snowies. Have tweaked late afternoon pops a bit, and have ended any chance of showers in our east by 03z. Subsidence and clearing will occur tonight as shortwave ridge builds in from the northwest. Temps tonight will be well below normal. In fact, records at Miles City (47) and Billings (49) may be approached. Also, given the precip in our far east today and current dew points in the lower 50s, there seems to be a risk of patchy fog east of Miles City and Broadus late tonight. Earlier runs of the HRRR were suggestive of this. Dry and warmer conditions on tap for Monday, though easterly surface winds will keep mixing in check and temps still below normal. Look for highs to the upper 70s and lower 80s. Next clipper from western Canada will approach our region Tuesday. We`ll see a bit of pre-frontal warming and temps further into the 80s. Canadian front will begin to make its way into our cwa sometime Tuesday night. Models are in some disagreement with the frontal timing and strength, but could see some light shower activity especially in our west/northwest Tuesday night. JKL .LONG TERM...valid for Wed...Thu...Fri...Sat...Sun... Models are in fairly good agreement from midweek into early next weekend. Models continue to show high pressure ridging over the Pacific northwest Wednesday into Friday which will result in a northwest flow aloft across our forecast area. This will keep temperatures below normal for most of the period. Some weak energy gets trapped under the ridge bringing a slight chance for a shower/thunderstorm basically each afternoon/evening mainly Thursday into Friday. A stronger disturbance may affect the forecast area Saturday but models differ in strength and timing of this disturbance. The GFS brings it across eastern Montana into the Dakotas but the ECMWF shifts it further west into our central and eastern areas. In any case, we will continue with chances for showers and thunderstorms for Saturday. Temperatures for the most part will be in the lower 80s Tuesday through Friday before warming to around normal values in the middle to upper 80s to around 90 degrees next weekend. Hooley && .AVIATION... VFR conditions expected tonight across the region. Some fog and low ceilings possible after 06z through mid morning Monday from KMLS eastward but especially along and near the Dakota borders. Walsh && .PRELIMINARY POINT TEMP/POPS... Mon Tue Wed Thu Fri Sat Sun ----------------------------------------------------------- BIL 051/081 055/083 056/081 056/080 055/084 057/086 058/090 00/U 01/B 12/T 12/T 11/U 01/U 11/U LVM 045/081 048/082 048/080 049/080 048/084 050/087 051/089 00/U 01/B 23/T 13/T 22/T 11/U 11/U HDN 048/082 052/085 056/083 056/083 055/086 056/088 058/092 00/U 01/B 12/T 12/T 11/U 01/U 11/U MLS 050/081 057/086 060/083 057/081 058/083 059/087 060/091 10/U 01/U 12/T 21/B 12/T 00/U 00/U 4BQ 048/081 054/084 056/082 055/082 055/082 055/086 058/090 10/U 01/B 12/T 11/B 22/T 00/U 00/U BHK 045/078 050/083 054/079 052/079 052/080 054/084 055/087 20/U 01/U 13/T 21/B 22/T 10/U 00/U SHR 045/078 050/081 053/079 052/078 052/081 052/084 055/087 00/U 01/B 12/T 13/T 22/T 11/U 11/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service State College PA
1010 PM EDT Sun Aug 6 2017 .SYNOPSIS... An area of low pressure will move out of the Tennessee River Valley to near Philadelphia by late Monday. High pressure will bring drier and more seasonably cool temperatures for mid week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Radar continues to show an area of light rain skirting the Mason-Dixon line. The biggest issue overnight will be the timing of the northward advance of the rain ahead of a deepening shortwave dropping into the lower Gr Lakes tonight and Monday. The HRRR shows the rain blossoming northward starting around midnight. The SREF/GEFS agree with this late night expansion north as the upper jet entrance region strengthens from southern NY to the southern New England coastal waters. The ECMWF/GFS also favor my southern zones for the best chance of rain, with the area north of about I-80 seeing the least...if any. I lowered the pre-midnight pops and have basically slowed the progress of the rain as a result. Min temps will vary from the mid 50s NW to the low-mid 60s in the SE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... Rain continues off and on through the day on Monday. Temps will climb just 5-10F during the day Mon, with the greatest rise likely across the far north where rainfall should be relatively lighter. Max temps could hold in the mid 60s from the the Central and NE zones where the steadiest rain is expected to fall into slightly lower dewpoint air well north of the quasi stnry frontal boundary. Both WPC excessive rainfall and SPC severe outlooks place the SErn portion of the CWA into their respective marginal risks. Shear is high enough to support gusty winds, but the lack of CAPE from the initially wet column and cooler-than- normal surface temps should greatly limit the depth and severity of the storms, especially as the sfc low passes near or just SE of our far SE zones late Monday afternoon. Forecast storm total rainfall should stay well below even the lowest 6-hourly FFG values of 1.5 inches, so for now, no flood watch is expected to be issued. PWATs climbing to near 1.8 inches late Monday, could support some periods of rainfall rates between 2-4 tenths of an inch per hour. Rainfall tapers of late Monday/Monday evening and some partial clearing late with just a light NW breeze could lead to patchy fog. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Improving conditions on Tuesday as weather system moves off the coast. High pressure will bring a couple days of really nice weather with temperatures a few degrees below average Tue and Wed. As high moves east and return flow of moisture develops will bring pops back into forecast with more humid conditions to end the work week. Trof will reestablish itself by next weekend with continued unsettled weather and temperatures below mid August norms. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... VFR conditions across Central Pennsylvania this evening. Radar showing increasing moisture and developing rain across the southwest. A few embedded heavier convective cells /maybe an isolated TSRA/ south of KJST. Clouds will continue to lower and thicken as rain overspreads the area overnight from the west. Ceilings and visibilities will drop into the MVFR/IFR range late tonight and early Monday. Widespread MVFR to IFR ceilings with mainly MVFR visibilities are expected Monday in a steady, chilly light to moderate rain. A light southwest to southeast wind across Central PA will become light and variable for tonight, and favor a light southeast direction on Monday at all TAF sites. .OUTLOOK... Mon...Periods of light to stratiform rain. Chance of a few embedded thunderstorms across the central and southern TAF sites between 16Z and 23Z Monday. Tue...Chance of a few light showers early, then improving. Wed...No sig wx. Thu-Fri...Chance of mainly afternoon SHRA/TSRA. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...Lambert LONG TERM...Ross AVIATION...Jung/Lambert
Area Forecast Discussion
National Weather Service Dodge City KS
606 PM CDT Sun Aug 6 2017 ...Updated Aviation Discussion... .SHORT TERM...(This afternoon through Monday) Issued at 1225 PM CDT Sun Aug 6 2017 Satellite imagery at noon shows stratus clouds eroding rapidly in response to early August sunshine. A beautiful afternoon on tap, with sunshine and mild temperatures for this time of year, ending up within a few degrees of 80 (normal is lower 90s). All locations dry through 7 pm, at least. With a continued light moist easterly upslope wind, have high confidence that stratus will return to SW KS tonight. Latest HRRR iterations forecast numerous thunderstorms along the Colorado Front Range by 7 pm, with these storms weakening as they arrive at the KS/CO border around midnight. 12z NAM shows a similar scenario, but is slower, showing convective leftovers arriving in the western zones in the predawn to sunrise hours Monday. As such, chance/scattered pops for rain showers and isolated thunder favor the western counties (west of Dodge City) through sunrise. These showers are expected to prohibit any fog formation, but can`t rule out some patchy fog again with the anticipated widespread stratus (especially eastern zones). Lows Monday morning in the lower 60s. Monday...Cloudy and unseasonably mild, decidedly unusual for early August. Clouds expected to hold tough much of Monday; even if/when the stratus erodes, forecast soundings show an overcast near 10-15k ft that will limit insolation. As such, forecasting highs only in the mid to upper 70s for most locales. With upslope E/NE wind components persisting, coolest temperatures west and warmest (lower 80s) near Medicine Lodge. Models agree that scattered afternoon convective coverage will favor the western/NW zones Monday afternoon/evening, and arranged pop grids accordingly. .LONG TERM...(Monday night through Sunday) Issued at 207 PM CDT Sun Aug 6 2017 Long term continues to look wet, with multiple rounds of showers and thunderstorms expected. Medium range models show a very stagnant synoptic pattern, with the main steering features (flat ridge over the SW, broad trough over the northern plains) changing very little in location or amplitude all the way through next week. As such, W/NW flow aloft will be locked in over SW KS for the next several days. With the medium range models unanimously in agreement on this pattern, the FB starting point pop grids were in decent shape, showing a chance of showers and/or thunderstorms virtually constantly Tuesday through next weekend. It will not rain the entire week; no need to build an ark. Numerous, difficult to time, shortwaves embedded in the flow will pass occasionally, and how these waves interact with the diurnal heating cycle and various surface boundaries will determine thunderstorm coverage and placement on a daily basis. Bulk shear provided by moderate W/NW flow aloft will combine with sufficient CAPE to support multiple rounds of thunderstorms, along with probable periodic MCS generation. Some severe weather and/or heavy rain is likely, with these threats of course most likely during the late afternoon into the overnight hours. 12z ECMWF still cranks out 1-2" of QPF cumulatively for SW KS for the upcoming week. 12z GFS is even wetter, at 2-4". With plentiful clouds and precipitation, afternoon temperatures will remain mild. Struggling to get to 80 on Tuesday, and holding in the 80s through this forecast period. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 604 PM CDT Sun Aug 6 2017 Surface winds will gradually veer more east to southeasterly overnight as a surface ridge axis crosses the Central Plains. This east to southeasterly wind in the lower levels overnight will draw more humid air back into southwest Kansas which will give rise to another round of low MVFR and IFR stratus along with some MVFR visibilities in patchy fog. In addition to the increase low clouds overnight there will also be a chance for scattered showers and thunderstorms as an upper level trough crosses southwest Kansas between 09z and 15z Monday. Areas most favorable for this convection late tonight will be west of a Hays to Dodge City to Liberal line. Confidence is not high on timing and just how far east these storm will move late tonight through Monday morning so have decided to stay close to the latest HRRR, ARW, and NMM on timing and eastward progression for now. && .PRELIMINARY POINT TEMPS/POPS... DDC 61 78 61 78 / 20 30 30 30 GCK 62 77 61 75 / 40 40 40 40 EHA 60 73 60 77 / 40 50 40 30 LBL 64 77 63 78 / 30 40 30 30 HYS 62 76 61 75 / 30 30 20 40 P28 65 83 64 82 / 10 10 10 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Turner LONG TERM...Turner AVIATION...Burgert
Area Forecast Discussion
National Weather Service Des Moines IA
640 PM CDT Sun Aug 6 2017 .SHORT TERM.../Tonight through Monday/ Issued at 330 PM CDT Sun Aug 6 2017 Showers struggled to develop across both southern and northern Iowa throughout the day due to a general lack of forcing and moisture depth. CAMs were slow to catch on, but eventually did so and show lack of activity throughout northern and southern Iowa into early this evening. Not inclined to disagree with better forcing located both further north and south. Better forcing will move into NW Iowa this evening as a mid-upper level shortwave/vort max approaches. Unfortunately, synoptic models and CAMs not in great agreement with various progressions, coverage, and intensities. The general consensus would suggest a more progressive movement with entrance into NW Iowa around 06z and southward progression through the morning and afternoon. Have leaned that way with the forecast. A few solutions indicate slower progression and would hold onto POPs state wide through peak heating, but do not see that as the most viable given surface high pressure moving in with ample dry air. Showers that form will ultimately be inconsequential. Overnight primarily just showers then a few lightning strikes possible in a daytime environment of just a few hundred J/kg MLCAPE. Backing up, fog potential tonight proving tough to nail down. Cloud cover the wild card in this case with light winds and low level moisture around in enough abundance. Current cloud trends suggest partly cloudy to clearing skies through central Iowa this evening, with both northern and southern Iowa still relatively entrenched in cloud cover. Uncertainty reflected in short term models, with 12z ARW and NMM both aggressive with fog coverage, while 18z RAP and HRRR less so, but still keying on southern and southeast areas. Given uncertainty, have put a smattering of fog in the grids, with greatest coverage/density over the S and SE. .LONG TERM.../Monday night through Sunday/ Issued at 330 PM CDT Sun Aug 6 2017 Weak shortwave ridging and subsidence will be in place Monday night into Wednesday morning as surface ridge slides through the state. Temperatures will remain below normal during this time with dry cool Canadian air statewide. Warm advection will intensify on Wednesday ahead of the next shortwave dropping into the northern Plains. Moisture transport will increase across Nebraska into the Dakotas where the bulk of storms are expected by Wednesday afternoon. The low level flow will begin to veer on Wednesday night with instability axis shifting east toward Iowa and storm chances will increase Wednesday night into Thursday morning. Severe chances remain relatively low with limited instability during this time. This system will depart into Thursday evening with another break in activity. Temperatures are expected to remain unseasonably cool during this time with airmass behind the system from Canada. Models begin to diverge toward the end of the period with Euro a bit more active by next weekend vs the drier GFS. In both instances, temperatures will remain below normal. && .AVIATION.../For the 00Z TAFS through 00Z Monday evening/ Issued at 630 PM CDT Sun Aug 6 2017 Main concern for the latest TAF package is the potential for MVFR or lower cigs/visby late tonight into tomorrow morning. The spatial coverage of low to mid level cloud cover will have an impact on fog formation and visby reduction. Forecast confidence continues to be hindered as model guidance has yet to come into a sound consensus. Latest trends point to southeastern Iowa as the most favorable area for fog and significant visby reductions. This includes KOTM where IFR or LIFR conditions are possible at times. Further north, bkn to ovc cigs may inhibit widespread fog development, so the forecast remains with IFR or higher visby for now. Warmer temperatures in the DSM metro overnight may limit the fog potential altogether, but MVFR cigs remain possible. Improvement to VFR conditions is expected across the area by mid to late morning, and persist through the remainder of the day. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Curtis LONG TERM...Cogil AVIATION...Martin
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
922 PM CDT Sun Aug 6 2017 .EVENING UPDATE... Continuing to evaluate the overnight PoP/Wx/QPF potential for the northern half of the CWA. Run to run consistency of the HRRR/HRRRX/TTU-WRF have proven to be poor in handling the overall evolution of the convection to our north currently. However, analysis of the mesoscale environment indicates still 1000-2000 J/KG of SBCAPE just north of the Austin area but instability has been trending down quickly. Additionally, low level lapse rates are beginning to decrease with the loss of diurnal heating. Thus, believe convection located immediately north of the Burnet/Llano area will continue their downward trend in intensity over the next hour or two. However, more intense convection farther north continues to overachieve compared to mesoscale model solutions and confidence is increasing in this complex slowly dissipating over the next several hours but making it far enough south to bring showers and storms into the northern tier zones, possibly including Austin around 05-06Z. The biggest concern would be heavy rain potential given VAD wind profiles indicating weak mid level flow and PWAT values 2"+ according to RAP mesoscale analysis. However, this should mostly be lifted by outflow and will lack thermodynamic support, so believe flash flood potential should be minimal but a quick inch or two of rain could be possible. Gusty outflow winds of 30-40 mph could also be a secondary concern. && .PREV DISCUSSION... /ISSUED 653 PM CDT Sun Aug 6 2017/ UPDATE... See below for the 00z aviation discussion... AVIATION... Currently VFR at all terminals under partly cloudy skies with southerly surface winds. Shower activity never materialized at the Interstate 35 sites, and with daytime heating beginning to diminish, have elected to remove VCSH from AUS/SAT/SSF. Strong convection just west of Del Rio from this afternoon has also since dissipated. VFR conditions should prevail for the rest of the afternoon and evening hours at all terminals. MVFR ceilings are expected to develop around 7z at AUS and by 9z at SAT/SSF before returning to VFR by late Monday morning/early Monday afternoon. The attention then turns to precipitation chances at the Interstate 35 sites. With ample moisture in place and the cold front/stationary front sagging further southward toward central Texas, it looks like a pretty strong bet that AUS will see scattered to widespread rain showers beginning somewhere in the 9z ballpark with thunderstorm chances coming later in the day by around 16z. Confidence for rain/storms is less for the San Antonio region, but have VCTS in the TAFs beginning at 15z and continuing through the afternoon hours. DRT is expected to remain VFR for the entire forecast period. Some high-res models suggest a chance for some isolated showers and thunderstorms Monday evening, but confidence in this was not high enough to include in the TAF. Winds will remain generally out of the south/southeast between 7 and 12 knots for the TAF forecast period. PREV DISCUSSION... /ISSUED 246 PM CDT Sun Aug 6 2017/ SHORT TERM (Tonight through Monday Night)... A frontal boundary stretches from central Oklahoma to southeastern New Mexico this afternoon This boundary will move slowly southward during this period and be the primary driver of our weather. Ahead of the front low level winds have been and will continue to be from the south to southeast. This has dew point temperatures in the 70s across our CWA. With ample moisture in place the front bring increasing chances for showers and thunderstorms during the period. There will be higher POPs tonight in the northeast and these will spread south and west Monday and Monday night. Deep moisture will mean there could be some heavy downpours in spots, but we do not expect widespread heavy rain. Heavier rain will likely be across the north central and northeast. LONG TERM (Tuesday through Sunday)... The front will stall and linger across central Texas north of our CWA Tuesday and Wednesday and rain chances will remain elevated for those days. The boundary will push back to the north away from our area Thursday. This will return us to the more typical summertime pattern with isolated to scattered showers and thunderstorms during the afternoon and evening Thursday and Friday. The upper level ridge will move over the region for the weekend bringing an end to rain chances across our CWA. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 78 95 76 93 75 / 40 70 70 50 40 Austin Bergstrom Intl Airport 78 94 75 92 74 / 40 60 60 50 40 New Braunfels Muni Airport 77 95 76 93 74 / 40 50 50 30 30 Burnet Muni Airport 75 92 72 88 72 / 50 70 70 50 40 Del Rio Intl Airport 79 98 77 93 77 / 40 30 40 30 30 Georgetown Muni Airport 77 93 74 90 73 / 50 70 70 50 40 Hondo Muni Airport 78 98 76 95 74 / 20 40 50 30 30 San Marcos Muni Airport 77 95 74 91 74 / 40 60 50 40 40 La Grange - Fayette Regional 79 94 76 92 75 / 30 60 50 50 30 San Antonio Intl Airport 79 96 77 93 76 / 30 40 50 30 30 Stinson Muni Airport 79 97 77 94 75 / 30 40 50 30 30 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Mesoscale/Aviation...Williams Synoptic/Grids...TB3 Public Service/Data Collection...YB
Area Forecast Discussion
National Weather Service Hastings NE
625 PM CDT Sun Aug 6 2017 .SHORT TERM...(This evening through Monday) Issued at 251 PM CDT Sun Aug 6 2017 It`s been a cool day under low clouds/stratus through the morning and well into the afternoon. While not a complete clearing line, visible satellite shows the breaks in cloud cover are near Ord, Kearney and Elwood. In areas of with more insolation, temperatures have risen to the mid/upper 70s while in areas of cloud cover readings averaged in the upper 60s to around 70F. Light rain showers have been weakening across north central Kansas this afternoon and should diminish by evening. The pattern aloft continued to feature northwest flow across the Central Plains with a broad trough from Alberta to Quebec south through the Ohio Valley region. Farther upstream, a low pressure system was moving into Oregon/northern California with weak ridging in British Columbia. With little change in the pattern, temperatures will remain cool and below normal for August. This evening and tonight, subtle disturbances embedded in the northwest flow regime are expected to generate showers and thunderstorms across the high plains and northern Nebraska. The brunt of the convection should remain to our north/west this evening, then reach our western zones overnight into Monday morning. Not looking for any of the storms to be strong or severe with instability generally 500 j/kg overnight. Low cloud cover is also expected to settle back in tonight and the potential for fog remains a concern and some areas could see a period of dense fog. Models are not in great agreement where the lowest visibilities will be with the SREF/NSSL WRF suggesting the lower visibilities along the Platte River mainly Kearney east, while the RAP keeps the lowest visibility`s across western Neb. Have focused the potential for lower visibilities east of where rain may be falling, generally along/east of Hwy 281 and north of I80, but will need to monitor trends. Rain showers/isolated thunderstorms chances continue into the first part of the day Monday mainly in our western/southern zones, keeping conditions cloudy/cool again for several hours before recovering in the afternoon. Temperatures will see little change from the weekend with highs averaging in the 70s. .LONG TERM...(Monday night through Sunday) Issued at 251 PM CDT Sun Aug 6 2017 The extended periods will remain in a northwest flow regime aloft, with the broad trough across Canada into the Northern/Central Plains, on east to the northeast CONUS. The cooler Canadian airmass will keep temperatures below normal through the workweek into next weekend with highs averaging in the 70s for the most part, and lows near 60. A series of disturbances translating southeast through the flow will bring periodic chances for showers and thunderstorms with the better chances focused in the Tuesday night/Wednesday time and again Friday/Friday night when stronger shortwave troughs are forecast to cross our region. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday) Issued at 623 PM CDT Sun Aug 6 2017 There are a couple of concerns for tonight. There will be some low clouds and visibilities will drop and IFR conditions are expected toward morning. The other is that there could be a few thunderstorms around the terminals. KEAR has a better chance for some than KGRI. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Fay LONG TERM...Fay AVIATION...JCB
Area Forecast Discussion
National Weather Service Goodland KS
542 PM MDT Sun Aug 6 2017 .SHORT TERM...(This afternoon through Monday) Issued at 205 PM MDT Sun Aug 6 2017 NW flow aloft transitions to more of a west-southwest flow, with a coupled upper level jet structure forecast to build over the Central High Plains late tonight through Monday. Moist southeast flow will continue to feed into the region, and as upper level forcing increases widespread showers and thunderstorms should develop from the west to the east overnight tonight. I can`t rule out an isolated thunderstorm this afternoon, but with subsidence in place at this time and main forcing still well west before 00Z it`s hard to say where this would be favored. There might be a brief period of subsidence in the afternoon Monday between mid level vort maxes that could create a lull for parts of our CWA, but we may still have lingering showers across our west and only a decrease in intensity. Regarding severe threat: SPC Mesoanalysis already shows 1500 J/KG ML CAPE along CO/KS border, match trends from earlier RAP and through the early evening moderate instabilty may be in place. Bulk Effective shear is forecast to be in the 30-45kt range, so there could be a window for a few organized severe cells before instability drops off before 03Z. Favored locations are going to be west based on expected thunderstorm timing/favored location during this limited window. Regarding heavy rain threat: PWATs 1-1.5" will combine with favorable thermal and "skinny" CAPE profiles to support very efficient rain processes. Models are showing strong overlap with high QPF across our west for the 36hr period. Considering the potential for slow thunderstorm motion or backbuilding we could have localized flash flood threats. The question will be how widespread and where if there is a heavy rain threat, with instability limited at times across our CWA. Ultimately this may end up being a prolonged moderate rain event where the totals are spread out, and instantaneous rates remain less than flash flood guidance. I leaned against a flash flood watch during this update, but I did play up wording in both forecast and HWO. .LONG TERM...(Monday night through Sunday) Issued at 205 PM MDT Sun Aug 6 2017 Shower and thunderstorm chances persist throughout the long term period as weak shortwaves move through the west to northwest flow aloft. A stronger disturbance continues across the High Plains from the Rockies Monday night through Tuesday night, generating showers and thunderstorms. With abundant moisture filtering into the region and PWATS in the 1 to 1.5 inch range, locally heavy rainfall will be a concern during this timeframe and flash flooding will need to monitored. Conditions dry out midweek behind the passing disturbance, but with persistent northwest flow, patchy precipitation chances are strewn throughout the forecast area. Predictability of locations and timing are made difficult by the variability of this weather pattern. It is even tougher to have confidence in periods further out. That being said, guidance suggests that a shortwave will travel through the Plains at the end of the work week as a cold front approaches from the north, crossing the area by Sunday. Cannot rule out precipitation through the weekend. Temperatures gradually warm during the long term period, but remain below normal. Highs start in the low/mid 70s on Tuesday and climb into the low/mid 80s by Friday. Lows remain in the mid 50s to low 60s. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 533 PM MDT Sun Aug 6 2017 VFR to IFR conditions forecast for the TAFs. Primary focus is the timing of rainfall and associated lower ceiling. Have more confidence of when the rainfall/low ceiling will begin and duration for KGLD than KMCK. May end up needing to place rainfall in a prevailing group for KMCK, but do not have high enough confidence for this TAF. Moderate to heavy rainfall is likely to occur at KGLD during the overnight, just not enough confidence of when an how long it will last to mention in this TAF. For both sites the ceiling may be IFR longer into the morning than currently forecast, but have ceiling improving based on trends this morning and what is typical for both sites. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...JBH AVIATION...JTL
Area Forecast Discussion
National Weather Service Houston/Galveston TX
824 PM CDT Sun Aug 6 2017 .UPDATE... After some storms - some rather feisty, prompting a severe thunderstorm warning - earlier this afternoon, the radar shows only a few remnant sprinkles in the area late this evening. As such, have pretty significantly trimmed back PoPs through the first part of the night while tweaking temperatures and dewpoints for observations, as rain cooled things off slightly more quickly this evening. Attention now turns to the MCS over North Texas. The HRRR seems pretty off on intensity, and roughly an hour behind on timing. This is not particularly surprising as the model often seems to propagate MCSs too slowly, severely impacting timing forecasts at longer range. So, what is progged to reach our northern areas, including College Station, around 4 or 5 am, may be sooner. Because of this, went above guidance on PoPs for the latter half of the night. This blends pretty closely with FWD and SHV to our north. While intensity is not a particularly big concern, there could be a marginal threat for strong to severe wind gusts up north while the low level jet is tangential to the line until it weakens and veers towards sunrise. Despite the buzz on social media, sharknado threat for Southeast Texas will be nil tonight. Luchs && .PREV DISCUSSION... /ISSUED 647 PM CDT Sun Aug 6 2017/ AVIATION... Quiet and VFR this evening at area TAF sites as daytime activity continues to dissipate. Eyes turn to our N and NW as north Texas SHRA/TSRA and associated boundaries work their way closer to our area later tonight and on into tomorrow morning and potentially bring MVFR ceilings/visibilities to the area. Generally expecting S winds under 10 knots tonight and around 10 knots tomorrow outside of the storms. 42 PREV DISCUSSION... /ISSUED 339 PM CDT Sun Aug 6 2017/ DISCUSSION... A weakness in the subtropical ridge will continue to allow westerly upper level shortwave troughs to bring good chances for showers and thunderstorms to Southeast Texas on Monday and Tuesday. By Wednesday the models show the ridge of high pressure drifting northward and building into the area; although, with still a weakness in the ridge overhead. This ridge will likely continue to build overhead through the end of the week. Early next week there are indications that the center of the ridge will weaken enough for either a westerly upper level system to dig down into the Southern Plains or an easterly wave to move into the Upper Texas coastal waters. Or, there will be a combination of both. The scattered thunderstorms occurring this afternoon should diminish in coverage by early this evening. Overnight tonight do expect chances to increase once again, especially over the northern counties as the frontal boundary over the Red River Valley drifts southward. An upper level shortwave trough will then help enhance the rain chances areawide on Monday. CAPE values around 4100 and PWs near 2.3 inches show the potential for isolated strong storms with some potential also for locally heavy rainfall. The models keep the weakness and shear axis aloft on Tuesday, leading to continued chances for rain and thunderstorms. Forecast PWs continued near 2.3 inches; however, forecast CAPE values were lower--about 2.1 inches--and sounding showed a more skinny CAPE profile. Rain chances will diminish during the mid and latter part of the week as the ridge builds overhead with least chances Thursday through Saturday. This should lead to slightly higher daytime temperatures and for the heat index to reach into the 104 to 107 degree range each day from Thursday through Sunday. On Sunday rain and thunderstorm chances will be on the increase once again. MARINE... The SCEC has been extended for nearshore and offshore waters until 12Z tomorrow morning as south winds should continue in the 15 to 20 knot range with seas running 3 to 4 feet. Widely scattered showers and thunderstorms will continue primarily during the morning hours over the coastal waters through the first half of the upcoming week. Mariners should continue to monitor the progress of a tropical disturbance as it moves westward across the Yucatan Peninsula and into the Bay of Campeche towards the middle of the week. This disturbance will likely remain well to our south, increased swell could begin impacting the offshore waters as early as Wednesday. 44 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 78 91 75 92 75 / 50 70 60 50 40 Houston (IAH) 80 91 77 90 76 / 30 60 40 60 30 Galveston (GLS) 82 90 81 89 81 / 30 40 30 50 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 7 AM CDT Monday for the following zones: Coastal waters from Freeport to the Matagorda Ship Channel out 20 NM...Coastal waters from High Island to Freeport out 20 NM...Matagorda Bay...Waters from Freeport to the Matagorda Ship Channel from 20 to 60 NM... Waters from High Island to Freeport from 20 to 60 NM. && $$ Discussion...25
Area Forecast Discussion...UPDATED
National Weather Service Huntsville AL
908 PM CDT Sun Aug 6 2017 .NEAR TERM...(Tonight) Issued at 908 PM CDT Sun Aug 6 2017 A weak mid-level shortwave will continue to push into the southern Tennessee Valley late this evening and through the overnight hours. This feature will serve as a lifting mechanism for shower and thunderstorm activity in this very moist air mass. There is still a bit of uncertainty as to exactly how expansive coverage will be, however. The current round of showers and storms are moving in slightly earlier than anticipated and there may be a break in the activity at so sometime after midnight. However, one aspect aiding in further redevelopment (and thus a wetter forecast) is the deep Gulf moisture in place as dewpoints are in the low to mid 70s, with PWATs close to two inches. Given this and the aforementioned boundary close by to focus this moisture, think that we should not have too much trouble maintaining fairly consistent, widespread showery activity through the night. Have adjusted PoPs to Categorical in the near term west of I-65 and south of the Tennessee River (to account for the latest trends on radar) and have likely PoPs prevailing through most of the night given the latest guidance from the RAP and HRRR. The main impacts from this activity will be locally heavy rainfall and lightning. Given the lack of appreciable instability, think the threat for a strong or severe storm is fairly low. Given this very soupy air mass, low temperatures will only drop into the lower 70s. .SHORT TERM...(Monday through Monday night) Issued at 226 PM CDT Sun Aug 6 2017 A cold front will move east of the Mississippi River by daybreak on Monday, as the surface low moves into he Ohio Valley. This front is expected to move eastward and reach the I-65 corridor by 18Z. Mid and upper level flow will generally remain zonal and therefore the front will have a hard to making much progression. Once again, forecast models differ on when and just how far south the front makes it, but feel pretty confident that it will at least make it through most of the forecast area on Monday. Convergence along the front will be sufficient to keep scattered to numerous showers and thunderstorms going tomorrow, with chances decreasing as the front passes through. As it continues to pass through NE Alabama, the mid level shortwave will intensify and aid in the forcing along the front. This may help produce some heavier rainfall, but whether that produces flash flooding will greatly depend on rainfall accumulations through Monday morning. The severe threat may be slightly higher across areas east of I-65 Monday afternoon, but still not looking at much of an organized severe threat. Not overly confident on how much destabilization we will realize, given the prolonged period of cloud cover and rainfall. So, if we are able to realize some instability tomorrow afternoon, gusty winds will be possible within any storm that is able to maintain a strong updraft. Although there are some model differences, the front is expected to push southeast of through the overnight hours on Monday and into Tuesday morning. This will bring an end to the more widespread precipitation across the TN Valley. However, lingering scattered thunderstorms will persist through much of the overnight hours, as the front meanders through and the airmass behind the front does not really modify too much. Given the lingering moisture and additional upper level disturbances moving in the near zonal flow aloft, have kept the scattered pops in through the 12 hour period. .LONG TERM...(Tuesday through Saturday) Issued at 226 PM CDT Sun Aug 6 2017 The forecast from 12Z Tuesday onward is relatively unchanged from yesterday: a broad trough pattern over the eastern CONUS with a quasi-stationary front wavering back and forth over the Tennessee Valley. There is strong agreement on the overall pattern, but details (such as small shortwaves) will matter greatly, and such details often can`t be resolved at this time range. There is good consensus that the front will have pushed across much of the area (if not all of it) by 12Z Tuesday, so blended model guidance creates a tight PoP gradient from SE to NW. However, this slight cool/dry shift should be short-lived, as the driving shortwave lifts NE and the front lifts back ever so slightly towards the AL-TN state line. Beyond that, it is difficult to pinpoint the surface wind shift and the moisture gradient relaxes. While the front may become rather diffuse, the combination of minor convergence with subtle, weak shortwaves will be enough to aid convective initiation. Indeed, blended guidance pinpoints Thursday as a time period of interest due to a slightly-stronger shortwave-- but again, these are details that won`t be resolved well at this time range. So beyond Thursday, PoPs are capped at 50%. Temperatures will be largely persistence with no more than 3-5 degree variation for highs, and no more than ~3 degree variations for lows. It is entirely possible that some days end up being drier and hotter than model/ensemble consensus predicts right now. Precipitable water values will remain high throughout this uncertain period, so pockets of heavy rainfall will be a concern. At this point there is no synoptic signal for organized, persistent heavy rain, but mesoscale effects or repeated heavy rainfall could create a localized flash flood threat. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 640 PM CDT Sun Aug 6 2017 A stalled frontal system will produce periods of showers and thunderstorms across the region overnight, with prevailing MVFR visibilities and ceilings likely after midnight. After sunrise, uncertainty increases with where the frontal boundary will set up and how extensive coverage will be. Think that TSRA will be more likely from the late morning through the afternoon, but due to the aforementioned uncertainties, have maintained VCTS for now. Kept continued low ceilings through the end of the period. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...AMP.24 SHORT TERM...73 LONG TERM...BCC AVIATION...AMP.24 For more information please visit our website at
Area Forecast Discussion
National Weather Service Wilmington OH
958 PM EDT Sun Aug 6 2017 .SYNOPSIS... Occasional showers are expected tonight into Monday as a low pressure system moves east across the Tennessee Valley. High pressure and a drier airmass will then build into the region through mid week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Isentropic lift continues to support a west-east oriented band of light rain across southeast IN/northern KY/extreme southern OH this evening. Rain has been falling out of a mid-cloud deck, and measurements have been light -- mainly on the order of a tenth of an inch or less over the last several hours. Initially will follow the HRRR, which shows this band affecting the same area through the rest of the evening, possibly with a slight nudge to the north -- but given the tight gradient, areas near/north of Interstate 70 will likely stay dry through midnight as there is still some residual influence from a weak surface high. As low pressure tracks into western TN overnight, this will help the warm front (currently across southern KY) to lift north closer to the Ohio River. As such, expect lift to spread north and support some rain making it into western/central Ohio later at night, and PoPs reflect this trend. Have also continued the mention of isolated thunderstorms across the southern FA. Can already see convective elements downstream which when extrapolated would affect areas near/south of the Ohio River (where very weak instability may reside). While the heaviest rain looks to occur south of the FA, convection may produce periods of moderate rainfall overnight across portions of northern Kentucky/extreme southern Ohio. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... Pcpn will likely linger into Monday morning before tapering off from northeast to southeast through early afternoon as the low moves off to the east. A fair amount of cloudiness will likely linger though so will trend temperatures down a bit with highs in the low to mid 70s. High pressure will begin to build into the area Monday night, leading to decreasing clouds and lows in the mid 50s to lower 60s. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Upper flow becomes zonal by mid week as a trough pushes east. Surface high pressure developing under the confluent westerly flow aloft will move across the Ohio Valley Tuesday and Wednesday, bringing a period of dry weather. For Thursday, a pattern shift begins when the air becomes more humid in the circulation behind surface high, and the upper flow turns southwest ahead of the next trough. A few thunderstorms may develop Thursday in increasing moisture and forcing, affecting mainly southeastern locations. A low chance for thunderstorms will linger Friday as the system works east. Additional cooling aloft coupled with persistent moisture may lead to more prevalent thunderstorm activity Saturday and Sunday, but model inconsistency allows for below average confidence in this scenario. Lower than average geopotential heights through the period point to cooler than normal temperatures, with the temperature regime reinforced by periods of cloud cover and precip. Highs starting in the upper 70s Tuesday are expected to rise slightly to the lower 80s for the rest of the period, staying a bit below the normal mid 80s. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... Persistent band of steady but light rain continues to stretch from southern IN through northern KY/southern OH early this evening, affecting KCVG/KLUK. In fact, ceilings are still close to 10K ft in the light rain. Meanwhile, a sharp gradient to the rainfall has the remaining terminals dry at 23Z. Per HRRR, expect light rain to continue to affect Cincinnati terminals over the next few hours. Then the HRRR suggests that this initial band weakens/dissipates before low pressure passes south of the area and begins supporting more rain (further north) late tonight and Monday morning. Certainly agree with the latter, but am leery of the HRRR dissipating the initial band and thus continue light rain at KCVG/KLUK through the night, which will help to moisten the column and eventually support lower ceilings. How much ceilings drop is one of the main forecast challenges for this TAF cycle. Some guidance suggests ceilings dropping to IFR across most terminals. This is a plausible solution but confidence is low given the amount of moistening the column will need to achieve, particularly further north. Therefore, kept ceilings in the MVFR category, with visibilities following suit, later tonight and Monday morning as the second round of showers closer to the low affect the area. MVFR ceilings may linger for a while into the afternoon even after the rain ends. OUTLOOK...No significant weather expected. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...JGL NEAR TERM...BPP SHORT TERM...JGL LONG TERM...Coniglio AVIATION...BPP
Area Forecast Discussion
National Weather Service Northern Indiana
730 PM EDT Sun Aug 6 2017 .SYNOPSIS... Issued at 725 PM EDT Sun Aug 6 2017 There is a chance for light showers across the region overnight with most showers confined to areas south of route 24. A second system will bring another chance for light showers on Monday...especially in the afternoon. Lows tonight will drop into the 50s. Highs on Monday will be in the 70s. High pressure will move back into the Great Lakes and Ohio Valley region Monday night and continue through Thursday with dry and comfortable conditions. The next chance for rain is expected for next weekend. && .SHORT TERM...(This Evening through Monday) Issued at 213 PM EDT Sun Aug 6 2017 Lead weak short wave moving from plains through the Great Lakes region today generating some light showers across mainly southern areas. Precipitation has struggled to move north given limited moisture advection and weak dynamics/kinematics aloft. Hires guidance has this handled fairly well and shows mainly scattered light showers across southern third to half of forecast area into this evening then pivoting east Monday morning with weak theta-e surge and some possible increase in coverage far southeast. Current forecast has this trend handled and only making some minor adjustments to PoP gradient based on latest hires models. Main trough axis to drop south on Monday with decent vorticity advection and some residual low level moisture along with mid-level lapse rates hovering around 6-6.5 C/km . Timing with diurnal heating and residual theta-e air may lead to another afternoon with isolated to scattered showers...especially central and southeast. Once this trough moves through clearing and drier conditions expected. && .LONG TERM...(Monday Night through Sunday) Issued at 213 PM EDT Sun Aug 6 2017 Mostly quiet and tranquil weather this week with normal to slightly below normal temperatures expected. Large area of high pressure to set up across the region through Thursday. This high finally slides east as another short wave begins to drop south from the northern Plains towards Friday and the upcoming weekend. Weak troughiness and surface low pressure may hang around for the weekend leading to low pcpn chances at this projection time. Will follow blends and keep low chance pops for the Fri-Sun periods. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) Issued at 729 PM EDT Sun Aug 6 2017 VFR conditions anticipated through the forecast period. Primary focus for showers to likely remain north/south of forecast sites. Improved conditions over prior KFWA forecast with lesser potential for MVFR cigs per latest model cross sections. Shortwave energy also to likely shunt south of northern Indiana terminals on Monday per the latest trends in HRRR signals and maintain dry forecast, though concede some sprinkles/brief shra possible. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...Murphy SHORT TERM...Lashley LONG TERM...Lashley AVIATION...Murphy Visit us at Follow us on Facebook...Twitter...and YouTube at:
National Weather Service Jackson KY
1201 AM EDT Mon Aug 7 2017 .UPDATE... Issued at 1201 PM EDT SUN AUG 6 2017 With widespread rain overspreading the area, have opted to increase pops to categorical across the board and max them out. In fact, we are seeing some decent rainfall rates with 1.34 in the last hour and a half at the McCreary county mesonet station. Dual Pol estimates are indicating even more than that to the north of that station. Potential for some minor flooding will be possible overnight given these rainfall rates. Areas that are dry now, should see rain move in over the next hour or two. Also updated to decrease thunder chances in the north with most of the thunder confined to the south. UPDATE Issued at 946 PM EDT SUN AUG 6 2017 HRRR model is not exactly consistent run to run in forecasting the evolution of precip across the area tonight, but is consistent in bringing rain at some point. Showers and thunderstorms are currently moving in from the southwest. Have timed these into the region for the next couple of hours while blending into a more generalized forecast. UPDATE Issued at 557 PM EDT SUN AUG 6 2017 Rain has become prevalent over the northern part of the forecast area late this afternoon, and the POP has been raised to reflect obs in that area. The precip has also suppressed the temps there, and adjustments have also been made for this. && .SHORT TERM...(This evening through Monday night) Issued at 436 PM EDT SUN AUG 6 2017 A center of surface low pressure is currently moving eastward across southern Missouri this afternoon, and should continue along this track, traversing the state of Kentucky during the short term period of the forecast. A warm front associated with this low is currently lifting north into the state as well, where it is expected to linger tonight and into the day Monday before the low pressure center pushes it eastward in the afternoon. Monday night the low and associated frontal boundary are expected to exit the state, leaving behind drier northerly flow in its wake. As for sensible weather, scattered to numerous showers and isolated thunderstorms are ongoing across much of Kentucky, mainly the northern half as of 4pm. Storms are now also starting to fire across south west and south central KY. As the warm front continues to lift toward the JKL CWA this evening and overnight, expect showers and thunderstorms to become more numerous in nature, peaking just ahead of the low pressure system Monday morning (highest POPS in the southern and eastern portion of the CWA). High pops will then slowly shift east of the area through the remainder of the day Monday and into Monday night as the low pressure system exits. The best chance for thunder activity will be along and just ahead of the warm frontal passage, where the best WAA will be found. As such, kept mainly rain in the northern half of the CWA through this afternoon until the warm front lifts farther north overnight. Chances of thunder were mentioned through the day Monday, but as the low pushes eastward, winds should quickly shift to a more Nrly direction on the backside. This should usher in cooler and more stable air, cutting off best convective potential across all of eastern KY. Therefore, removed any chance for thunder Monday evening/night for the lingering moisture/precip. Any thunderstorms that occur during the day tomorrow could be strong with heavy rains, gusty winds and frequent lightning, however not looking too much in the way of severe activity as the best wind shear/cape/and drying aloft do not seem to line up at the same time. Can`t rule out some isolated events however. SPC only included a general thunderstorm outlook across our area tonight through tomorrow. There is some concern about the amount of rainfall that will occur with this system. While heavy rain will be likely given our proximity to the low pressure center and strong WAA from the south, it is still somewhat uncertain as to exactly how much. The latest NAM12 is the most robust, with 2 to 2.25 inch PWATs Sunday night into Monday. Meanwhile the GFS shows around an inch or less. WPC notably upped their guidance with their afternoon issuance as some model trends have done the same. That being said, was a bit concerned these amounts (nearly 2 inches over a 12 to 18 hour time period across the central and southern CWA) were too high for that widespread of an area. Though, isolated instances in the heaviest storms will be possible. Superblend seemed to have a more reasonable toned down approach, so ended up blending the two, leaning a bit more towards Superblend. Thereby this gave generally between 1 and 2 inches across much of the central and southern CWA (highest amounts far south). Amounts in the north will generally be around an inch or less due to having less time in the warm sector, and rain tapering off here more quickly. .LONG TERM...(Tuesday through Sunday) Issued at 417 PM EDT SUN AUG 6 2017 The long wave pattern continues to look rather stagnant across the CONUS through the period. Broad troughing will hang around across most locations east of the Rockies, while ridging remains locked in the across the Desert Southwest. A surface boundary will also remain in the vicinity of the Tennessee and Ohio valleys through the period. The weather will begin a little quieter across eastern Kentucky, with a few showers gradually diminishing from north to south, as a cold front slips south into the Tennessee Valley, while high pressure moves across the Ohio Valley through Tuesday night. Through the rest of the week, this frontal boundary will move back north, and looks to remain in the vicinity of our area from Wednesday through Sunday. Have not played up any individual shot of better forcing, given the detail uncertainties this far out. As such, allowed for more of a diurnal influence to the POPs each day, with chances peaking around 50 percent at times in the afternoon. Temperatures will average near to just below normal through the period, with highs generally in the low to mid 80s and lows in the low to mid 60s. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 839 PM EDT SUN AUG 6 2017 VFR conditions were present almost everywhere at the start of the period. A bit of light rain was present near and north of I-64, but was not presenting much in the way of restrictions. However, the situation should change during the night. Showers and thunderstorms over middle TN and south central KY will continue to head toward the northeast, bringing IFR or worse conditions with them to the JKL forecast area overnight. The poor conditions are expected to last into the day Monday. Some improvement is expected during the course of the day, but the extent is uncertain. At this point the forecast calls for most places to go to MVFR in the afternoon. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...JMW LONG TERM...GEOGERIAN AVIATION...HAL
Area Forecast Discussion
National Weather Service North Platte NE
637 PM CDT Sun Aug 6 2017 .SYNOPSIS... Issued at 300 PM CDT Sun Aug 6 2017 At H5 strong closed low over the ridge all the way into the Yukon. Quasi blocking pattern developing over the west coast. Quasi blocking pattern to the south of Greenland. These features are allowing a broad trough across the Northern CONUS. && .SHORT TERM...(This evening through Monday) Issued at 300 PM CDT Sun Aug 6 2017 Models in fair agreement in the near term...will trend towards short term HRRR solutions and NAM. HRRR shows this mornings area of rainshowers exiting southwest Nebraska and then subtle weak waves moving east through the upper flow regenerating thunderstorms over northern Nebraska this afternoon and continuing through the evening. Stronger wave moving across northeast Colorado will bring thunderstorms to southwest Nebraska tonight as surface high pressure moves south into the central plains. Areas of fog to develop over southern Nebraska again Monday morning. Continuing chances rainshowers and thunderstorms through the day on Monday. Lows tonight in the 50s and highs on Monday in the 70s. .LONG TERM...(Monday night through Sunday) Issued at 300 PM CDT Sun Aug 6 2017 The current upper air pattern will hold through the end of the work week till it begins to transition as the upper ridge to the west begins to shift east. As a storm moves across the southern Gulf through the week upper high over northern Mexico will build and move north into the Desert Southwest allowing waves to move out of the base of the trough along the west coast and move over the central Rockies into Western Kansas. This will enhance chances for thunderstorm development over southwest Nebraska through Friday. A stronger wave moves south out of Canada into the northern plains Friday with increased chances for precipitation over northern Nebraska Saturday. Warmer and dry Sunday. Temperatures through mid week in the 70s with lows in the 50s. Highs tough the weekend around 80 and lows around 60. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 609 PM CDT Sun Aug 6 2017 Local radar display shows scattered showers and thunderstorms mainly over the Sandhills moving southeast. A few storm may strengthen and become strong, otherwise storms will largely be low-end with gusty winds and brief heavy rainfall expected with them. Showers and thunderstorms will continue southeast and move across north central-central NEB and limited portions of southwest NEB through the early and mid evening hours. Current thinking is development on the southern edge of the convective activity may pose a threat in terms of -TSRA to the KLBF terminal early this evening thus the use of TEMPO. Otherwise, KVTN TAF will carry VCTS given unorganized nature and present activity in vicinity and upstream. Potential for low ceilings to MVFR beginning late tonight, after Midnight central, increases across northern NEB then to southwest NEB. Conditions improve to VFR anticipated through mid-late morning. && .HYDROLOGY... Issued at 300 PM CDT Sun Aug 6 2017 Due to releases from Lake McConaughy river levels will remain high on the North Platte River at North Platte. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Power SHORT TERM...Power LONG TERM...Power AVIATION...ET HYDROLOGY...Power
Area Forecast Discussion
National Weather Service Memphis TN
932 PM CDT Sun Aug 6 2017 .UPDATE... A warm front remains across Northeast Arkansas, the Missouri Bootheel, and Northwest Tennessee this evening. The front will gradually sink back southward overnight. Latest HRRR runs shows best chances for rain will occur over West Tennessee near the Tennessee River and portions of North Mississippi during the overnight hours. Will update to adjust POPS accordingly. Will also mention patchy fog for northwestern portions of the CWA. Update will be out shortly. KRM && .DISCUSSION... /issued 320 PM CDT Sun Aug 6 2017/ Skies are partly to mostly cloudy across the forecast area this afternoon with temperatures ranging from the mid 70s to around 90 degrees. A warm front continue to move north through the region with only portions of northeast Arkansas remaining north of the boundary. Some showers have already moved into the forecast area this afternoon. The warm front will continue to move north during the remainder of the afternoon before a cold front starts to move into northwest Arkansas this evening and into central Arkansas overnight. As a result, more showers and thunderstorms are expected to develop tonight. Temperatures will be a little warmer than the last couple of night with lows Monday morning in the low to mid 70s. On Monday, the cold front will start to drop south into the forecast area reaching north Mississippi by late afternoon. This will mean more showers and thunderstorms especially over portions of north Mississippi. Temperatures will be cooler than today with highs in the low to mid 80s. By Monday night, the cold front will drop further south reaching into central Mississippi by Tuesday morning. There will still be a chance of thunderstorms over much of north Mississippi with dry weather expected over northern sections of the forecast area. Temperatures will be a little cooler Monday night with lows Tuesday morning in the mid 60s to lower 70s. The frontal boundary will remain south of the forecast area for both Tuesday and Wednesday but there will still be a small chance of thunderstorms both days with north Mississippi seeing the higher chance of rain. The front will start to move north into the forecast area on Thursday and stall out and weaken on Friday so there will still be a chance of thunderstorms both days. A new cold front will move into the central plains on Saturday and move into the forecast area next Sunday. This will mean more showers and thunderstorms will be possible both days. Temperatures will be rather warm but remain below normal levels from Wednesday through next Sunday. ARS && .AVIATION... An MCV is moving through the area resulting in scattered SHRAs and a few TSRAs. This activity will continue to push east and diminish this evening. Expect low clouds to develop across the area after midnight with IFR and possibly LIFR conds at KMKL and KJBR. Some light fog is also possible. Conds will gradually improve on Monday. Best chances for SHRA and TSRA activity will be at KTUP in the afternoon. SJM && && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion...UPDATED
National Weather Service Miami FL
1158 PM EDT Sun Aug 6 2017 .UPDATE... As of 1158 PM EDT...Quick update to the forecast to bump up PoPs along the east coast to chance overnight, as latest mesoscale model guidance and radar trends suggest slightly higher coverage in shower/storm activity overnight streaming in off the Atlantic. Most of this activity will be light in nature, but a few of the showers will be capable of brief heavy downpours. Rest of forecast on track with no further updates needed at this time. && .PREV DISCUSSION... /issued 808 PM EDT Sun Aug 6 2017/ AVIATION...Isold SHRA/occasional TSRA will affect east coast terminals from KFXE southwards through around 03Z. TS affecting KAPF and VCNTY should diminish after 01Z. Can`t rule out a few ATLC SHRA, but overall expect dry conditions overnight beyond current activity. East coast sites remain ESE 8-12kts overnight, picking up to 10-15kts after 13Z. SHRA activity picks up after 15Z. For KAPF, Gulf breeze looks unlikely again Mon, with SCT TSRA in VCNTY after 19Z. UPDATE... NWS radar loop displays hit and miss showers streaming over the peninsula from the southeast, with the overall trend in coverage decreasing. Short term models prog deeper moisture to advect in off the Atlantic tonight, maintaining at least the threat for light to moderate showers along the east coast metro region through Monday early morning. A warm and muggy atmosphere will once again lead to elevated minimum temperatures. Along the east coast, temps may only fall into the low 80s, tying or exceeding various high minimum record values. PREV DISCUSSION... /issued 406 PM EDT Sun Aug 6 2017/ DISCUSSION...Latest visible satellite imagery shows scattered cu streaming in from the southeast. Most of this cloud cover has produced little in the way of precipitation, but a few light to moderate showers have been rung out. Though the PWAT value on this mornings sounding was just shy of 1.50", models continue indicate deeper moisture advecting over the region from the southeast this afternoon and into the evening. Short term models, including the HRRR and NAM12 and WRF show isolated showers over the Atlantic, increasing in coverage through late this afternoon. Another area of slightly more significant shower and storm development is expected from the Gulf to the western interior, where the weak Gulf breeze collides with southeast flow. The main impacts from any storms that develop will be brief heavy downpours and cloud to ground lightning. A strong and elongated cell of high pressure stretching from the Gulf to the western Atlantic will provide subsidence, and very warm conditions at the surface. Maximum temperatures will generally top out in the low to mid 90s, a few degrees higher than seasonal norms. Tonight, moist southeast flow will allow shower activity to continue over mainly the Atlantic waters, periodically affecting the east coast metro. Minimum temperatures will only dip into the low 80s, once again tying or potentially breaking high minimum temperatures records. Monday through Friday: A fairly stagnant synoptic weather pattern will hold with high pressure aloft to the northeast of the region and surface high pressure centered near Bermuda. This will allow for brisk southeast winds to continue through mid week. Low level moisture and instability should be sufficient enough to produce afternoon and evening thunderstorms mainly over the interior and Gulf region. Expect warm and muggy nights with the shower potential continuing along the east coast metro region. Thursday into Friday, both the GFS and ECWMF prog a TUTT low pressure system to approach southern Florida from the east. This feature should act to further increase moisture and instability over the CWA and bring more a widespread precipitation threat. MARINE...Increasing east southeast flow tonight, 15 to 20 kt, will lead to small craft need to exercise caution, mainly for the Atlantic waters and outer Gulf waters. Expect choppy seas. For the remainder of the week, seas will generally be 3 feet or less, except 4 feet at times in the Gulf Stream. Isolated to scattered showers and storms will be possible over the next few days, especially during the nighttime hours, with increasing chances towards the end of the work week. BEACH FORECAST...Persistent southeast winds around 15 mph tonight into Monday afternoon will lead to moderate to high chances of strong rip currents along the east coast beaches of Palm Beach, Broward, and Miami-Dade counties. && && .PRELIMINARY POINT TEMPS/POPS... West Palm Beach 82 92 82 92 / 30 40 30 30 Fort Lauderdale 82 91 82 91 / 30 30 30 30 Miami 81 92 81 92 / 30 30 30 30 Naples 77 94 78 92 / 20 50 30 50 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. GM...None. && UPDATE...92/IRL DISCUSSION...27/JT MARINE...27/JT AVIATION...23/SK BEACH FORECAST...27/JT
Area Forecast Discussion
National Weather Service Reno NV
902 PM PDT Sun Aug 6 2017 .UPDATE... Showers and thunderstorms remain over the far northern and eastern portions of the forecast area this evening...but the intensity has decreased quite a bit. Earlier...satellite imagery indicated quite a lot of low level dry air moving into the western parts of the forecast area. While not reflected in lower dew points based on surface observations...this area did see a marked decrease in convective activity as the drier air moved in. The latest High Resolution Rapid Refresh model...and the latest NAM and a decrease in activity overnight with the main concentration over the far north and the eastern third of the forecast area. Some lingering showers are also possible over southern Mono and Mineral counties. We will update to the reflect that forecast trend. We will also drop the Flash Flood Watch as the threat of additional heavy rain causing flash flooding has ended. Updates out soon. && .PREVIOUS DISCUSSION... /Issued 1221 PM PDT Sun Aug 6 2017/ SYNOPSIS... Low pressure stalled over northern California will produce thunderstorms with heavy rainfall possible through midweek. A few storms could become severe and produce flash flooding this afternoon and evening. Drier weather returns late in the week. Temperatures will remain slightly below average through Wednesday, followed by some warming. SHORT TERM... Upper area of low pressure remains nearly stationary over northern California, keeping a steady stream of moisture into the Sierra and northwest Nevada. With clear skies to start the morning, outside of central NV eastward, it helped to destabilize the atmosphere further. The 12z and 18z KRNO soundings showed a cap around 500 mb, which may hold off initial convection until early afternoon, but will also allow storms to get going faster once it breaks. The HRRR agrees with this idea with rapid storm development after about 20z, or 1 pm local time. When modifying the KRNO sounding, was able to get 500-1000 J/kg of CAPE and -4 LI, which lines up with forecast model soundings as well. Forecast soundings are also indicating increasing PWATs through the day, pushing toward nearly 1" by late afternoon. This value, climatologically, is indicative of increased flash flood risk, especially given the fact that storm motions overall will be less than 10-15 kts. A Flash Flood Watch remains in effect through this evening for much of northeast California and northwest Nevada, with a heightened risk for recent burn scars and steep terrain. The Tahoe Basin and eastern Sierra was kept out of the watch due to the westerly zephyr afternoon winds helping to push any storms that do develop eastward. The greatest storm risk today will be locally heavy rainfall. Gusty outflow winds in excess of 50 mph, small hail, and frequent lightning area all risks as well. Today may bring a mix of severe storms and flash flooding based on the current forecast parameters. Showers and isolated thunderstorms are likely to continue into the overnight hours as well. PWATs remain high, just over 1" according to KRNO forecast soundings, through midweek with the upper low remaining over north central California. The big question at this time is the amount of lingering cloud cover. Frequently, we can become clouded over once the atmosphere becomes that moist, which then ends up limiting thunderstorm coverage; this was what happened Saturday. Forecast models and sounding are indicating increasing amounts of CAPE through Wednesday, however extensive cloud cover could keep this from being fully realized. Will maintain scattered thunderstorm coverage in the forecast Monday-Wednesday at this time with locally heavy rainfall likely to be the greatest threat. -Dawn LONG TERM... Upper low begins to shift eastward by the end of the week with some increase in southwest flow. This will finally start to bring a drying trend to the region, however there will be enough lingering moisture and instability for a few storms to form Thursday and Friday afternoons, especially near favorable convergence zones. A warming trend is also on tap for the end of the week going into the weekend, with high temperatures about 5 degrees above normal. An upper low moves into the Pacific Northwest coast for the start of next week which is likely to increase southwest to west winds across the eastern Sierra and northwest Nevada. The current forecast position of the low should keep a dry and stable airmass over the region and thunderstorms are not anticipated. -Dawn AVIATION... Fairly widespread showers and thunderstorms are expected this afternoon and evening bringing locally heavy rainfall, gusty and erratic outflow winds of 40 kts or greater, small hail, and frequent lightning. Storms are expected to form between 19-21z and continue through approximately 04-06z this evening. A few showers with isolated thunderstorms may continue through the night. Storms may obscure terrain and bring localized MVFR-IFR conditions. Chances for a thunderstorm to pass over a terminal and best timing for each location today (Sunday) are: KRNO and KCXP: 60% 20z-01z KTVL and KTRK: 40% 20z-23z KMMH: 50% 19z-00z KLOL and KNFL: 60% 21z-04z Ongoing wildfires continue to bring hazy conditions to the region, but the overall flow and recent precipitation has helped to improve visibility today compared to Saturday. -Dawn && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ For more information from the National Weather Service visit...
Area Forecast Discussion
National Weather Service Blacksburg VA
1123 PM EDT Sun Aug 6 2017 .SYNOPSIS... Low pressure developing over the Central Plains this morning will track north and east today and tonight, pushing a warm front north through the Mid Atlantic region during the overnight hours. By late Monday, the low will be over Pennsylvania with a front trailing back into Texas. The front will remain across the Tennessee Valley and Carolinas Tuesday through Thursday. && .NEAR TERM /THROUGH MONDAY/... As of 1115 PM EDT Sunday... Updates this evening have been mainly to adjust pops to better match current radar and satellite trends as well as hires HRRR guidance. HRRR is in good agreement with current trends of showing leading edge of expanding precipitation area to our southwest entering the southwest part of the CWA around 06Z, then overspreading the entire forecast area from southwest to northeast in the 08Z to 12Z time frame. Have trended pops from slight chance to categorical during this time frame, from southwest to northeast. No thunder mentioned in this time frame, but will need to watch the northwest NC area as there are a couple of lightning strikes in the activity just south of the CWA border at this hour. Temperatures will be much warmer tonight than last night thanks to the significant increase in low-level moisture, and cloud cover. The bulk of the cooling may wait until the rain arrives later tonight. Only minor adjustments were needed to the T and Td readings. As of 300 PM EDT Sunday... A broad upper trough remains over the central and eastern United States through tonight. This should allow a more focused synoptic lift to reach the forecast area in the form of a short wave approaching from the Tennessee Valley, and general upper diffluence strengthening across the northern portions of the Middle Atlantic. A surface low now situated near the AR/MO state boundary and it`s associated warm front extending into Georgia and the Carolinas will move north and east tonight, overspreading widespread rainfall throughout the forecast area. This will also provide a wind shift around to the southwest and a further influx in low level moisture, providing a healthy boost in dewpoint temperatures. As a result, radiational cooling will be limited, all the while precipitable water values will be on the rise, with 2.0 inch values reestablishing for areas east of the Blue Ridge Mountains. Best probability of precipitation will be after midnight in the west, with a general spread eastward lasting most of the daylight hours on Monday. Precipitation amounts have the potential to top the one inch amount through this period, with locally higher amounts possible. The best axis of precipitation will likely fall near the VA/WV border with higher POPs as you progress south to near TN. Isolated ponding or flooding will be possible, but dry antecedent conditions should work in our favor here. A rumble of thunder is certainly not out of the question in the southern and eastern portions of our forecast area Monday afternoon and evening, however, abundant cloud cover and persistent showers will likely work to inhibit convective instability. With that being said, if a few breaks in the cloud cover are able to occur, a strong storm or two in these areas who will be privileged to the warm sector of the forming cyclone will be possible. Hence the marginal risk by the SPC. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 300 PM EDT Sunday... High pressure will move out of the upper midwest behind the front and briefly wedge down east of the Appalachians by Wednesday. This will help push the frontal boundary just to our south but also set up some isentropic lift that will keep a chance of precipitation around for Tuesday and Wednesday, mainly south and west where there will also be a chance for thunder along the western/southern fringes of the wedge. The actual baroclinic zone with the old frontal boundary will become diffuse and rather ill defined as it lurks just off to our south. As the surface high translates eastward and the wedge loosens up, the broad frontal boundary will start to lift back northward into the region later on Wednesday with support from an upper level short wave increasing our chances for precipitation from southwest to northeast through Wednesday night. Expect temperatures to be on the cool side through midweek as the wedge keeps highs 5 to 10 degrees below normal. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 300 PM EDT Sunday... Short wave energy rounding the base of the shallow upper trof over the eastern US will drive a surface wave from from the lower Mississippi valley to the mid Atlantic region, nudging the diffuse frontal boundary to the north and placing the region into unstable moist air, before the wave forces the boundary back through as a cold front Thursday night. The combination of instability and synoptic lift associated with the passing wave and frontal boundary will bring a good chance of showers and thunderstorms. The low amplitude upper pattern will not be conducive to giving a good push to the frontal boundary, leaving it to stew just off to our south as another high wedges down east of the Appalachians for the end of the week. This will keep a good chance of showers/storms across Southside VA Friday with decreasing POPs to the northwest. As the surface high moves off the mid Atlantic coast on Saturday, the wedge will loosen and allow broad southerly flow to bring moist and unstable air and a good chance for showers and thunderstorms back to the forecast for the weekend. Given the overall unsettled conditions expected this week and potential for several wet periods with convective precipitation, a cumulative hydro threat may materialize in time. The combination of expected cloud cover and another wedge, temperatures will remain a few degrees below normal through the period. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... As of 745 PM EDT Sunday... Poor sub-VFR conditions expected through much of the TAF valid period. A warm front was lifting northward through the southeast states, which will spread deeper low-level moisture, clouds, and showers into the area from the south after midnight. Widespread rainfall and accompanying low ceilings and visibilities can be expected in place at most TAF sites by or after 08Z Monday morning. Little to no improvement in conditions is expected throughout the remainder of the TAF valid period as a strong upper-level disturbance approaches from the west during the afternoon. Given the extensive cloud cover and precipitation expected during the morning into the afternoon, instability will be minimal leading to low confidence in thunderstorms, although an embedded rumble of thunder during the afternoon cannot be ruled out, just not enough confidence to place in the TAFs at this time. Ceilings will be low end VFR until the rain arrives from the south in the 06Z-09Z time frame from southwest to northeast, after which point expect widespread MVFR-IFR ceilings and MVFR to IFR visibilities. Winds will be light and variable overnight into the morning hours Monday, favoring a southeasterly direction, then becoming SSW-SSE 4-6kts at most TAF sites by Monday afternoon. Medium confidence in ceilings and visibilities through the TAF valid period. Medium confidence in wind direction and speed through the TAF valid period. Low confidence in thunderstorm potential Monday. Extended Aviation Discussion... The frontal boundary will be briefly pushed south of the area Tuesday allowing for some improvement in aviation conditions. However, the front will return north Wednesday. A broad upper trough will remain in place across the Great Lakes dominating much of the eastern two-thirds of the U.S. A series of disturbances will rotate through the base of the trough and interact with the quasi-stationary boundary draped across or oscillation north and south across the region through the later half of the week. This will keep unsettled conditions in place much of the week with frequent periods of sub-VFR ceilings/visibilities, especially late night/early morning hours due to fog and low clouds. && .EQUIPMENT... As of 200 PM EDT Friday Aug 4... KFCX doppler radar will be down for the rest of the month due to a failing bull gear. The radar will only be made operational for brief periods if an imminent significant widespread severe weather and/or hydrologic event occurs. Operating the system for any amount of time until the bull gear is replaced risks a catastrophic failure that would further extend system downtime. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS/JM/RAB SHORT TERM...DS/MBS LONG TERM...MBS/WP AVIATION...JM/RAB EQUIPMENT...WERT
Area Forecast Discussion...UPDATED
National Weather Service San Angelo TX
950 PM CDT Sun Aug 6 2017 .UPDATE... The forecast has been updated to reduce PoPs to some extent across most of the southern half of our area for tonight based on trends in radar imagery, and to have increased cloud coverage. Showers and thunderstorms over San Saba County are about to merge with a larger area of convection moving south-southeast across central Texas. Heavy rainfall accompanies this convection. Other showers and a few thunderstorms are developing south-southeast into the far northern part of our area. The cold front should sag south into the Big Country overnight, and this is where much of the shower and thunderstorm activity should occur overnight. && .PREV DISCUSSION... /issued 704 PM CDT Sun Aug 6 2017/ AVIATION... /00Z TAFS/ Scattered thunderstorms continue this evening across our northern and central counties, with new development now occurring into the southern third of the area. Carrying a mention of thunderstorms in the KABI and KSJT TAFs at the start of the 00Z TAF period. Gusty winds remain possible in and near the thunderstorms. Temporary reductions in visibility and ceiling are possible in locally heavy rain accompanying the convection. Additional shower/ thunderstorm development is expected tonight. Carrying VCTS in the area TAFs, and will monitor radar imagery for TAF updates. A cold frontal boundary will make southward progress tonight and Monday, and carrying wind shifts at KABI (10Z) and KSJT (12Z). Additional convective development is expected during the day Monday, but timing and placement uncertainties preclude carrying more than VCTS at any of our TAF sites for now. Low cloud development early to mid-morning Monday across the Big Country should affect KABI with MVFR ceilings. PREV DISCUSSION... /issued 244 PM CDT Sun Aug 6 2017/ SHORT TERM... (Tonight) .Heavy rain and severe thunderstorms possible... Last nights convection/MCS over Oklahoma has produced an outflow boundary that is moving southward across the southern panhandle. This boundary, coupled with a slow moving east-west oriented cold front will bring widespread showers and thunderstorms across the area this afternoon and into the evening, with some storms becoming severe. Storm Prediction Center (SPC) has much most of the area in a marginal risk for severe thunderstorms. With temperatures climbing into the upper 90s and dewpoint values greater than 64 degrees under southwesterly flow. CAPE values have climbed in the 3000-3500J/kg range. Upper level support is rather weak, but with the added lift from the approaching cold front and the inverted surface trough, expect rapid thunderstorm development with strong updrafts. The main hazards with these storms will be the potential for strong downburst winds in excess of 55mph. Heavy rainfall will also be possible with these storms as PWAT values have climbed above 1.85". Both the HRRR and the TTU-WRF model show large clusters of showers and thunderstorms moving ESE across the Concho Valley and big County through the evening. This will be the start of the heavy rainfall event. Localized minor flash flooding is possible especially in poor drainage and low lying areas. Rainfall totals through the evening will be between a half to three quarters of an inch with localized heavier amounts of up to one inch. (Monday) Showers and thunderstorms look to be fairly widespread across West Central Texas, especially during the afternoon. Appears best push on the front may be east of the area late tonight where a MCS may be rolling across Central and East Texas. This would allow the front to hang up across West Central Texas, combining with a little afternoon heating and abundant moisture. After perhaps a lull in the thunderstorm chances for the morning, showers and storms should bubble up through the afternoon and become more widespread, especially along and south of I-20. Will keep the PoP chances for Monday at likely for most locations, and with precipitable water values up over 2 inches for most areas and storm movement expected to be slow, will continue the mention of locally heavy rainfall. Not everyone will see big rain totals, but some areas will likely see 1 to 2 inches pretty easily. As for temperatures, what may end up as a mostly dry morning will allow readings to climb, with afternoon highs in the 80s to near 90 still looking reasonable. LONG TERM... (Monday night through Saturday) A weak cold front will remain stalled somewhere across the central or southern portions of West Central Texas late Monday into Tuesday night. This will remain a focus for shower and thunderstorm development, so high end chance to likely PoPs were continued for this period. Precipitable water values will generally be in the 2- 2.25 range, with some higher values. This abundant moisture will result in the possibility of locally heavy rainfall. In addition, a few strong storms will be possible, with strong gusty winds being the main concern. High temperatures on Tuesday will be below seasonal normals, in the mid to upper 80s. The remnant weak cold front will still be in the vicinity of West Central Texas on Wednesday, so isolated to scattered showers and thunderstorms will once again be possible. Highs on Wednesday will be slightly warmer, generally in the upper 80s to near 90 degrees. Thursday into the weekend, weak upper level ridging will build across West Central Texas. Disturbances are forecast to rotate around the northern periphery of the ridge, resulting in shower and thunderstorm development. At this point, it looks like the majority of this convection will remain north and west of the forecast area, but slight chance/low end chance PoPs were continued for mainly the Big Country. && .PRELIMINARY POINT TEMPS/POPS... Abilene 73 86 70 86 / 70 60 50 50 San Angelo 74 90 71 88 / 50 60 60 60 Junction 73 92 72 88 / 20 60 60 60 Brownwood 73 89 71 87 / 70 60 60 70 Sweetwater 73 85 69 84 / 60 70 50 40 Ozona 72 90 71 87 / 30 40 60 60 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$