Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/24/17


Area Forecast Discussion
National Weather Service Albany NY
1033 PM EDT Sun Jul 23 2017 .SYNOPSIS... The area will receive a widespread rainfall tonight and Monday with chances for showers lingering through Tuesday as a low pressure system approaches and gradually moves across the region. Fair weather is expected for the mid week with more chances for rainfall Thursday and Friday. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... As of 1033 PM EDT...A vigorous short wave will move across the Great Lakes region tonight amplifying the trough and strengthen a surface low moving eastward along the stationary boundary to our south. Bands of convection have been ongoing since this afternoon across western and central NY, although this activity has been weakening as it heads eastward towards our area. At this time, no appreciable rainfall has occurred yet across eastern New York, with a rather stable atmosphere in place. Based on the latest 3km HRRR and NAM, showers will finally spread across our area from west to east after midnight and into the late overnight hours. We will continue to allow for a slight chance to chance of thunder for western and southern areas, as there may be just enough instability to allow for some rumbles in those areas. Otherwise, light rain showers will become more widespread by the late night hours across the whole area. By 3 to 5 AM, most areas should be seeing periods of rain showers. With increasing PWATs and a stregthening low-level jet, some pockets of moderate to heavy rainfall are possible (mainly across far southern areas). This may cause some minor flooding of urban or poor drainage areas, but widespread flash flooding is not expected because of the lower rainfall rates due to the limited amount of deep convection expected our area. Model guidance suggests the heaviest rainfall may just miss our area to the south (closer to the low track), although any subtle changes in this track could bring heavier rainfall closer to our area. Expecting lows in the lower to mid 60s in the valleys with mid to upper 50s across the higher terrain. Light winds will increase tonight especially across the higher terrain where easterly flow is enhanced by the local terrain effects. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Cool and wet Monday with highs 15 to 20 degrees below normal. Trough will sharpen however guidance keeps it positively tilted as it moves gradually across the region through Tuesday evening. Widespread showers are expected to persist across most of the forecast area through much of the day. The local area is expected to remain on the cool and stable side of the system as the surface low passes to our south. QPF amounts are uncertain however indications are the heavier rainfall should occur to the north and south of the local area. At this time, expecting 1 to 1 1/2 inches across the local area with the bulk of the rainfall occurring late tonight into Monday afternoon. Looking at highs only in the 60s with 50s across the higher terrain of the southern Adirondacks and southern Green Mountains. Easterly winds will be at their strongest Monday morning into the afternoon with gusts up to 30 mph in locations where an easterly flow gets locally enhanced by the terrain. Chances for showers will linger Monday night into Tuesday as the upper trough axis moves over the region. It will be cool again Tuesday with highs 10 to 15 degrees below normal mainly in the 60s with some 70s into portions of the mid Hudson Valley. The upper trough axis finally moves off to our east late Tuesday night and fair weather returns as we heads into mid week with near seasonable warmth with highs in the 70s with some 60s limited to the highest terrain of the Western Adirondacks, eastern Catskills and southern Green Mountains. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Unsettled weather looks to return to the region for the late week period, as a frontal system and associated upper level trough moves towards the area from the Great Lakes. Although it should be mainly dry to start for Wednesday night, the chance for showers and thunderstorms look to increase for Thursday into Thursday night, as the cold front approaches from the northwest. With a humid air mass in place ahead of the approaching boundary, some thunderstorms will be possible, mainly for during Thursday afternoon into Thursday evening. Lows on Wed & Thurs night will mainly be in the 60s with highs in the mid 70s to near 80 for Thursday. The models are still rather unclear on the exact timing of this feature and there is the chance that some steady showers (and perhaps some thunder) linger through all of Thursday night and into Friday, especially if a wave of low pressure develops along the frontal boundary. Even if the front does clear through, there still will be a chance for some lingering showers for Friday into Saturday thanks to the cyclonic flow due to the upper level trough overhead. Daytime temps will generally be in the 70s and overnight lows will be in the 60s, along with a partly to mostly cloudy sky. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... A storm system over the Great Lakes will spread towards our area tonight into impact the region through the day on Monday. Flying conditions are currently VFR with bkn-ovc cigs at 5-10 kts. Mesoscale models suggest that rainfall will spread across the area from west to east after Midnight, with flying conditions expected to lower to MVFR by late tonight (mainly for visibility). Some heavier pockets of rainfall (and possible thunder) could occur near KPOU, so have included a PROB30 there for IFR conditions for both vsbys/cigs due to a t-storm by late tonight. Otherwise, it will generally be MVFR with light rainfall for the second half of the overnight hours. E-NE winds will generally be 5-10 kts, although some higher gusts are possible for KPSF by late tonight into the day on Monday. The steadiest rainfall showers will start to taper off by mid to late morning on Monday, but additional on and off light rain showers can be expected through the remainder of the day. With plenty of lingering low-level moisture trapped under an inversion, expect MVFR conditions for cigs to continue through the rest of the day, although some improvement in visibility is expected. NE-SE winds will be around 10 kts for the day on Monday. Outlook... Monday Night: Moderate Operational Impact. Likely SHRA. Tuesday: Moderate Operational Impact. Chance of SHRA. Tuesday Night: No Operational Impact. Patchy FG. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: Moderate Operational Impact. Chance of SHRA...TSRA. Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Friday: Moderate Operational Impact. Chance of SHRA...TSRA. && .FIRE WEATHER... The area will receive a widespread rainfall tonight and Monday with chances for showers lingering through Tuesday as a low pressure system approaches and gradually moves across the region. && .HYDROLOGY... The area will receive a widespread rainfall tonight and Monday with chances for showers lingering through Tuesday as a low pressure system approaches and gradually moves across the region. Expecting QPF amounts from 1 to 1 1/2 inches with the bulk of the rainfall occurring late tonight into Monday afternoon. Some locally heavy rainfall may occur especially for areas west of the Hudson River Valley. Ponding of water on roadways would occur with the heavier rainfall along with some minor flooding of poor drainage and low lying areas possible. Fair weather is expected for the mid week with more chances for rainfall Thursday and Friday. 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...IAA NEAR TERM...IAA/Frugis SHORT TERM...IAA LONG TERM...Frugis AVIATION...Frugis FIRE WEATHER...IAA HYDROLOGY...IAA
Area Forecast Discussion
National Weather Service Amarillo TX
614 PM CDT Sun Jul 23 2017 .AVIATION... 00Z TAF Cycle VFR conditions will prevail at all three TAF sites through 00Z Tuesday. Isolated showers and thunderstorms can be expected across the Panhandles this evening, however low confidence on timing and location and whether any showers or storms will affect any of the three TAF sites. Decided to leave out a TEMPO group for now and instead left in VCTS at the Amarillo TAF site where a little better chance exists amongst the three TAF sites that could be affected. Otherwise, light east and southeast winds will prevail around 5 to 10 knots or less. Schneider && .PREV DISCUSSION... /Issued 421 PM CDT Sun Jul 23 2017/ DISCUSSION... Noteworthy items for this forecast package are limited with no real high impact weather. There is of course several chances for thunderstorms with Tuesday being the only real dry period. Some storms could be strong, but severe weather does not look likely over the next several days. In the near term, Thursday could possibly see some strong to marginally severe storms. Outside of this, temperatures will be right around normal for this time of year. Satellite trend this afternoon has shown a CU field developing over parts of the forecast area. Forcing is very weak with limited shear and instability. Any thunderstorms that form should be below severe criteria. Storms will also be slow movers which could lead to possible localized moderate to heavy rainfall in some areas. The HRRR has been consistently hinting at convection this afternoon across the Texas Panhandle. Showers are forming east of Amarillo and are anticipated to start filling in more across the forecast area, mainly southern parts of the Texas Panhandle. Tuesday in the only dry period--outside of small chances to the northwest--during this entire forecast package. Otherwise, thunderstorms are possible each day, but little to no shear will be our main limiting factor, especially during the afternoon hours. We could see changes in the future forecast packages, but at this time severe weather does not look favorable next week. Guerrero && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$ 11
Area Forecast Discussion
National Weather Service Columbia SC
934 PM EDT Sun Jul 23 2017 .SYNOPSIS... Upper level ridging will weaken across the area today as the upper level trough digs over the eastern US. A bermuda high will provide very warm and humid conditions through Monday with scattered afternoon and evening showers and thunderstorms. A weak cool front will stall over the area Tuesday, then move southward into southern Georgia on Wednesday before dissipating, providing somewhat cooler weather and a continued threat for scattered thunderstorms. High pressure will become re- established for the end of the week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Strong thunderstorms moved through the area late in the afternoon and evening. Satellite and radar trends suggest continued weakening during the late evening as the storms move to the south. Storms produced damaging winds and flooding. 2 to 4 inches rain fell in downtown Columbia. Convection will end during the early morning hours with some mid and upper level debris cloudiness through daybreak keeping low temperatures in the mid to upper 70s for most locations. Low level jet should limit fog late tonight although stratus possible. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... The forecast area will remain on the western edge of the Bermuda high through Tuesday night, while heights aloft slowly drop as a longwave trof becomes established over eastern North America. This combination will lead to hot afternoons with max temps generally in the lower to mid 90s, and maximum heat indices a little above 100. The combination of developing steep low level lapse rates each afternoon and weak vorticity aloft will lead to scattered afternoon and evening convection. PWs will range from 1.8 inches to 2.2 inches across the CWA, so any slow moving convection could dump some locally heavy rain in spots. Min temps will remain quite warm with lows in the mid to upper 70s most places. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... On Wednesday, a weak front will slowly slide through the CWA as a small area of low pressure develops off of the South Carolina coast and moves to the northeast. It`s main impact will be to dry the air out a little bit Wednesday night and Thursday, but max temps on Thursday afternoon will still be in the 90s as an increase in sunshine will offset any weak cool advection that tries to set up. Thursday will also see the lowest chance for afternoon and evening convection for the week. By Friday, the main global models begin to diverge with details, but the overall pattern indicates a digging shortwave will move into the southeastern states on Friday. This will cause an increase in the deep southwesterly flow, allowing moisture to quickly return in the form of clouds and scattered convection, especially during the second half of the day. The weekend contains a lot of uncertainty as the GFS shows a rather strongly amplified pattern for july with a significantly deep trough carving out over the southeastern states, while the ECMWF is much more progressive with the digging shortwave on Saturday and instead is more focused on the next shortwave, which is in the 7-10 day period and not part of this package. I have gone for generally unsettled weather due to the mean trof, without concentrating too much on the individual shortwaves. This means slightly above normal chances for rain and slightly below normal afternoon temps due to increased cloud cover. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... Thunderstorms threat at the terminals will be diminishing by 03z. MVFR conditions should improve to VFR with scattered cumulus and mid/high level ceilings. The hrrr model is indicating the potential for restrictions late tonight. Fog appears a lower threat than stratus due to low level jet...but with rainfall cant rule out visibility restrictions. All sites will be VFR from 14z through the end of the period with cumulus developing during the late morning hours through the end of the period as another round of convection is expected Monday afternoon. EXTENDED AVIATION OUTLOOK...Increasing confidence in restrictions in mainly afternoon/evening thunderstorms through Wednesday. We could also see some morning cig restrictions from stratus by Tuesday and Wednesday. The convection looks to decrease on Thursday, but should pick right back up again by Friday. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
Area Forecast Discussion...UPDATED
National Weather Service Cheyenne WY
959 PM MDT Sun Jul 23 2017 .UPDATE... Issued at 953 PM MDT Sun Jul 23 2017 An evening zone forecast update to remove slight chance PoPs for Converse and Niobrara counties. Recent HRRR radar reflectivity trends keep showers and thunderstorms to the north of these counties late this evening. && .SHORT TERM...(This evening through Tuesday) Issued at 217 PM MDT Sun Jul 23 2017 Pretty quiet and hot weather pattern will be in place through Monday with strong ridging aloft and limited monsoonal moisture. Visible imagery shows scattered cumulus across southeast WY with the best vertical develop along the southern Laramie Range near the Colorado border. While much of the CWA will remain storm free through the evening, the HRRR has been consistent at showing isolated convection developing by late aftn over the Laramie Range, spreading eastward into adjacent plains. Will maintain PoPs around 20 percent through the early evening. With deep boundary layers and high T/Td spreads, thinking that gusty outflow and downdrafts will be the main threat. The pattern will be similar for Monday with ridging/subsidence aloft keeping tstm chances rather limited. It will be the warmest day in the short term with highs rising into the 90s to low 100s across the plains. A sfc trough will stretch from around Laramie to Chadron during the aftn. Not expecting much convective initiation along the trough except in areas near the southern Laramie Range. The models continue to show midlvl flow becoming more southwesterly by Tuesday, which will transport subtropical moisture into the CWA, especially across southeast WY. The GFS has PW values rising to around 1 inch over areas to the west of the Laramie Range by Tuesday aftn. With a weak shortwave trough moving into northwest Colorado, there will be a much better chance of storms, particularly over the western mtns (Sierra Madre/Snowy Range). Heavy rain will definitely be a possibility with deep monsoonal moisture in place. Went ahead and increased PoPs over areas to the west of the Laramie Range by Tuesday aftn. .LONG TERM...(Tuesday night through Saturday) Issued at 217 PM MDT Sun Jul 23 2017 Energetic west-southwest flow aloft will keep an active pattern in place Tuesday night through Thursday. Monsoonal moisture will ride overhead within this flow pattern, so expect to see a good chance for showers and thunderstorms through this time. A front riding south across the forecast area Tuesday night will keep showers/storms ongoing through the night, with upslope stratus a good possibility in the post frontal environment Wednesday morning. The best coverage for convection Wednesday afternoon will be along and west of I-25. Return moisture in low level southeasterly upslope flow looks to combine with moderate values of bulk shear on Thursday to set the stage for a broader coverage of activity across the area, with perhaps a stronger storm or two. A ridge will build to our west on Friday, with a shortwave moving across Wyoming in west-northwest flow. This wave will drag another front south across the area with convection likely to be confined along the front and within the higher terrain. Saturday will be drier overall with warm temps and subsidence aloft. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 518 PM MDT Sun Jul 23 2017 VFR conditions are expected through the period. Light winds for the most part into Monday morning then becoming a bit gusty by late morning over parts of the Panhandle. && .FIRE WEATHER... Issued at 217 PM MDT Sun Jul 23 2017 Minimal fire weather concerns through the middle of next week. With a warm and dry airmass in place, minimum humidity values will drop to 13-20 percent over portions of southeast Wyoming this afternoon and Monday afternoon. We are not expecting any critical fire weather conditions however, as winds will be relatively light. An increase in monsoonal moisture on Tuesday and Wednesday will bring higher relative humidity values and a better chance of wetting rains. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ UPDATE...MAJ SHORT TERM...ZF LONG TERM...RJM AVIATION...RE FIRE WEATHER...ZF
Area Forecast Discussion
National Weather Service Peachtree City GA
802 PM EDT Sun Jul 23 2017 .UPDATE... Numerous showers and thunderstorms continue across the region, especially toward Athens. Those traveling I-85 north and along I-20 east of the metro ATL should heed caution as very strong storms may cross these interstates over the next couple of hours. Gusty winds, heavy rain and frequent lightning are the main threats. We have had some reports of small hail with these storms. Training of storms may also lead to localized flooding. Anticipate this activity to continue to move southeast and diminish through the evening with loss of daytime heating. && .PREV DISCUSSION... /Issued 734 PM EDT Sun Jul 23 2017/ PREV DISCUSSION... /Issued 308 PM EDT Sun Jul 23 2017/ SHORT TERM /Tonight through Monday Night/... Recent analysis of afternoon water vapor imagery reveals a mid level synoptic pattern over the CONUS characterized by a persistent ridge over the western US...and an amplifying cyclonic flow regime over the eastern US. The most notable feature east of the Rockies is a southeastward moving shortwave trough over the western Great Lakes. MEanwhile at the sfc...a weak sfc front extended roughly from the Great Lakes S/SW through IN,IL, MO, and AR...with a weak trough extending down the Piedmont of the Carolinas into Georgia. Rest of today and tonight: Forecast is complicated by numerous outflow boundaries and convectively induced perturbations in the mean flow. This morning`s MCS over KY has diminished...although its outflow boundary has helped several complexes develop over eastern TN and western NC. Think highest concentration of convective coverage will be across north Georgia where any larger scale outflow could be influenced by orographic processes and perhaps the weak sfc trough. Nonetheless...with MLCAPE between 2000-3000J/Kg across the entire CWA...storms could pop up anywhere. Downburst winds the main threat with low level lapse rates over 7C/km and PWs near 2 inches. The HRRR has been consistent in showing redevelopment across KY/TN towards sunset tonight /likely influenced by morning MCS and the weak front/. It is possible some of this convection could impact far north Georgia after midnight...though confidence is low given time of day and weak flow. Showing slight POPs for now to reflect this possibility...with a diminishing trend towards sunrise. Much of the same story for Monday as sfc troughing continues and Great Lakes shortwave moves into New England. Aforementioned weak front will likely be closer to the state...but still far enough away to not have a profound impact on convective initiation. Forecast will be complicated again by outflow boundaries and convectively induced perturbations in the mid levels. All things considered...trend should still remain largely diurnally driven. Temps will be hot...and it will be humid. Kovacik LONG TERM /Tuesday through Sunday/... No major changes to the long term from the previous forecast. A weak trough of low pressure will remain over the CWA early in the long term. This will develop into a closed low over Georgia by Wednesday and as the H5 ridge builds over the middle of the country, this will push the low out of Georgia however there are discrepancies in the models as to how much moisture will be pushed out as well. Due to this will maintain pops across the CWA for the latter half of the week. The next short wave will move out of the upper plains and toward the CWA toward next weekend increasing the chances of precip late in the week and next weekend. Temperatures will remain at or near climate norms through the long term. 17 AVIATION... 00Z Update... Scattered to numerous showers and thunderstorms moving across the northern TAF sites this evening. This activity will work south and likely dwindle with loss of heating. Some lingering isolated thunderstorms across southern TAF sites should decrease to just VCSH the next couple hours. While activity in TN is becoming better organized this evening, feel these thunderstorms will likely diminish as they cross far northern GA. VFR conditions are expected (apart from any precipitation activity) through the overnight as convective debris erodes. Fog/stratus formation seems fairly limited given dewpoint depressions. However, for those that received plentiful rain this afternoon/evening, you may see patchy ditch fog by early morning. CU decks will increase by mid morning tomorrow to around 4KFT. Another convective day in store with development expected by 16-17Z. West winds will continue through the TAF period. //ATL Confidence...00Z Update... Medium confidence on evening/overnight convection potential. High confidence on all other elements. 26 && .PRELIMINARY POINT TEMPS/POPS... Athens 96 75 91 73 / 60 40 50 40 Atlanta 91 75 89 74 / 60 40 50 40 Blairsville 89 69 85 67 / 60 50 50 40 Cartersville 92 73 88 72 / 60 40 50 40 Columbus 95 75 92 75 / 50 40 50 40 Gainesville 91 74 88 73 / 60 40 50 40 Macon 93 75 92 74 / 50 40 50 40 Rome 92 72 89 73 / 60 40 50 40 Peachtree City 92 73 90 72 / 60 40 50 40 Vidalia 92 76 92 74 / 60 40 50 40 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Kovacik LONG TERM....17 AVIATION...26
Area Forecast Discussion
National Weather Service Houston/Galveston TX
950 PM CDT Sun Jul 23 2017 .UPDATE... Convection continues to dissipate this evening across portions of the Piney Woods region and expect mostly dry conditions to persist through the remainder of the evening hours. However, rain chances for the overnight period remain a little more uncertain. Surface analysis shows a southward surging outflow boundary that has crossed the Red River into North Texas, with thunderstorms congealing along this outflow. Pressure rises behind it are not terribly impressive, but the thunderstorms developing along the boundary may support continued maintenance of the cold pool and allow it to reach Southeast Texas in the pre-dawn hours. High resolution guidance has not been terribly excited about overnight rain potential so far this evening, but the latest (01Z) run of the HRRR has begun to indicate a few showers (or maybe a storm) may be able to develop across parts of the Brazos Valley during the early morning hours. Whether or not this is actually from the outflow (or another more subtle boundary already located across the Brazos Valley... where interestingly Hearne has a light northerly wind and College Station has a southerly wind, indicating some weak surface convergence) remains to be seen. As a result, have readjusted rain chances to include 20 PoPs generally north of a Brenham to Cleveland line to account for uncertainty with the evolution of the outflow boundary (and potentially others). Otherwise south to southwest winds 5-15 MPH tonight and partly cloudy skies should keep overnight lows warm again in the mid 70s to mid 80s. Huffman && .PREV DISCUSSION... /ISSUED 637 PM CDT Sun Jul 23 2017/ AVIATION... A few shra/tsra will be possible over northern TAF sites through 03z before all of the precip comes to an end with the loss of daytime heating. Fcst soundings show high clouds hanging around for much of the night and into Monday. Fcst soundings also showing little in the way of saturation on Monday and warmer convective temps so will not mention precip in any of the TAFs on Monday. S-SW winds will not fully decouple tonight and will likely remain moderate on Monday. Could get some brief MVFR cigs Monday morning at northern TAF sites between 13-16z but dry air aloft should mix to the surface quickly and clouds will scatter out by mid morning leaving VFR conds for the rest of the day. 43 PREV DISCUSSION... /ISSUED 401 PM CDT Sun Jul 23 2017/ DISCUSSION... Coverage so far today has been generally north of I-10 and along and east of I-45. Still not ruling out some isolated development over the far NW counties through the early evening hours, but the bulk of the storms will likely remain over the central zones of SE TX. With the upper low near the TX/LA border continuing to weaken tonight, the ridge aloft out west will begin to build into the area tomorrow. Slightly less coverage is expected tomorrow and Tuesday as a result...with a corresponding bump up of daytime high temps. Would not be too surprised to see a few 100s at some of our sites with heat indicies 105-108 for most locations these next couple of days. Slightly deeper moisture progged to move in from the Gulf on Weds and scattered POPS (closer to the coast) will be possible. A return of mostly daytime seabreeze induced activity expected for the rest of the week. As for the extended forecast...models appear to be hinting that we might possibly see the passage of a very weak front. Will likely just leave lowish POPS in for the weekend and hope later runs add a bit more clarity. 41 MARINE... Showers and storms have been largely suppressed over our waters today as the bulk of today`s activity is either over land, or tucked closer to the upper disturbance off the SW Louisiana coast. Water vapor imagery shows that disturbance drifting westward, so parts of the waters off the upper Texas coast can likely look to see activity increase this afternoon and evening. Winds have not really come down significantly today, and so continue the SCEC through the night, as winds should stay up overnight. Of course, winds and waves can be expected to be even higher near any thunderstorms. Winds should gradually diminish and veer slightly as surface high pressure moves over the area. Along with that, waves should also slowly diminish from 2-4 feet to 1-3 feet. Relatively persistent onshore flow should keep tides running several inches above astronomical levels through the week, but should be well shy of tide levels associated with causing flooding issues. Luchs && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 77 98 76 97 78 / 20 20 10 10 10 Houston (IAH) 78 95 77 93 78 / 20 20 10 10 10 Galveston (GLS) 83 90 83 90 82 / 20 10 10 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...High Rip Current Risk until 7 AM CDT Monday for the following zones: Brazoria...Chambers...Galveston. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 5 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...14
Area Forecast Discussion
National Weather Service Jackson MS
348 PM CDT Sun Jul 23 2017 .DISCUSSION... Tonight through Monday: Latest RAP analysis shows only subtle westward movement to the upper- level low along the Louisiana coast so far today. While the broad mid-level subtropical ridge is somewhat evident across the Deep South, it has broken down considerably over the last day or so and become more centered back to our west over the Desert Southwest/Four Corners region. This has allowed for a downward trend in heat issues as a shortwave trough swings through the Great Lakes region. Clouds and an early start to showers and storms today have also helped to keep temps cooler than previous days. The only heat stress issues remain confined to the northwest Delta and western portions of the Hwy 82 corridor where a few sites have been close to or at the 105 degree heat index criteria, so will let the ongoing heat index continue through the rest of the afternoon. Numerous showers and storms are ongoing from GLH to HBG in closer proximity to the upper low and deep moisture axis. The greatest coverage of storms will remain in this area with only scattered coverage expected elsewhere through the rest of this afternoon with activity driven by outflow boundary interactions. Poor lapse rates and vertical totals will preclude a greater risk for mircobursts with updrafts struggling to become deep and sustained, however isolated flash flooding cannot be ruled out, especially with slow/training storms. Storms should dissipate after sunset, however a few isolated lingering showers will be possible through the overnight. Low temps will be generally be in the low to mid 70s. On Monday, the upper-level low that has been plaguing the area will become an open wave and get picked up by the departing shortwave trough lifting through the Great Lakes and into the Northeast. This will help to advect a deep moisture axis, characteristic of 2.25 inch PWATs, across south central Mississippi and increase shower and thunderstorm coverage. Weak 0-3km shear vectors will favor slow/training storms and combined with the aforementioned PWATs, saturated forecast soundings and Q-vector convergence will result in the potential for a few instances of flash flooding, especially along and south of the I-20 corridor and where heavy rain has fallen the past few days. As such, went ahead and added a limited area for flash flooding in the HWO to account for this. Otherwise, cloud cover and precip coverage will hold high temps to the mid to upper 80s. /TW/ Tuesday through Saturday: The weakness in the mid level ridge will begin shifting east during this time frame allowing the ridge to build back in by late week. As this occurs, a daily lessening of convective activity and cloud cover will be seen as max temperatures start creeping back up. Heat stress will become a problem once again by Wednesday as mid 90s heat and mid 70s dewpoints push heat indices above 105. This looks to continue through Friday, but by the weekend, troughiness looks to take shape over the eastern half of the nation with the ridge breaking down somewhat over the area as northwesterly flow back spread back into the region. A surface cold front will be associated with the mid level troughiness and drop through the forecast area Saturday afternoon. Some deep layered shear will exist in the pre-frontal environment, but lapse rates at present are feable./26/ && .AVIATION... 18Z TAF discussion: IFR/MVFR stratus lingering through the morning has lifted/scattered to VFR categories at most TAF sites. A few sites have briefly dropped to MVFR ceilings but the prevailing conditions are expected to remain VFR through the rest of today. Once again, scattered to numerous SHRA/TSRA are expected with a few areas already ongoing in the Delta and along the Hwy 84 corridor. VCTS cannot be ruled out at any one location this afternoon and early evening, but activity should dissipate by 24/3z. MVFR ceilings will once again be possible Monday morning at all TAF sites. /TW/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 73 87 73 88 / 29 62 31 52 Meridian 73 89 73 86 / 20 60 34 57 Vicksburg 73 87 73 90 / 38 60 30 40 Hattiesburg 73 87 72 88 / 34 59 41 59 Natchez 73 86 73 89 / 41 58 30 37 Greenville 73 90 74 91 / 28 58 29 38 Greenwood 73 88 74 89 / 23 58 31 44 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...Heat Advisory until 7 PM CDT this evening for MSZ018-019-025-026- 034. LA...None. AR...Heat Advisory until 7 PM CDT this evening for ARZ074-075. && $$
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1117 PM EDT Sun Jul 23 2017 .UPDATE... Issued at 1117 PM EDT SUN JUL 23 2017 Thunderstorms have pushed southeast into Tennessee, with only a few rogue showers and storms currently dotting portions of far southeastern Kentucky. These should exit before midnight, with generally dry weather expected the rest of the night, as deeper moisture has exited. Winds have stayed up enough thus far; however, given the clearing upstream, and plenty of rainfall having occurred along the Cumberland Valley, have played up the fog for the rest of the night. Updates have been sent. UPDATE Issued at 706 PM EDT SUN JUL 23 2017 Freshened up the POPs through tonight based on the latest radar and higher resolution model guidance trends. The best instability gradient has been shifting slightly towards the Tennessee/Kentucky border with time, with more sustained convection aligning from north central Tennessee to southwest Tennessee. Scattered convection has initiated across portions of the Cumberland Valley in the last 15 minutes or so, and will continue to advertise the highest POPs down in this area. Did tighten up the gradient of POPs more so to the north, where the last few runs of the HRRR has been suggesting more limited activity through this evening. Updates will be out shortly. && .SHORT TERM...(This evening through Monday night) Issued at 401 PM EDT SUN JUL 23 2017 MCV crossing east Kentucky into West Virginia has really zapped our instability today. We really don`t see much CU out there. There is a dewpoint/ouflow boundary draped across our far south, near Middlesboro, where instability is much higher to the south of this boundary. This would likely be the best area to see development this evening as dewpoints have remained in the mid to upper 60s back to the north. Temperatures have also remained a bit cooler today to the north. All of this together has really weakened the threat of storms for much of the area. With this in mind, have opted to drop the flash flood watch for the northern counties. Best rain chances will remain in the south closer to that boundary this evening. Should see activity diminish quickly by mid to late evening with dry weather expected overnight. With more clearing expected tonight, we could see a good deal of valley fog tonight. The cold front to the north will drop south tomorrow afternoon/evening and may allow a few showers or storms to pop up along the boundary at that time. Instability is rather weak, but given the middle of the afternoon, can`t rule out an isolated storm. As the cold front sinks to the south tomorrow evening, dry weather will be seen through Monday night. We may see another round of valley fog Monday night pending cloud cover. .LONG TERM...(Tuesday through Sunday) Issued at 440 PM EDT SUN JUL 23 2017 At the start of the period, a shortwave trough is expected to be moving through the Northeast and Mid Atlantic states with an upper level ridge centered over the Southern Plains region. Height rises At the surface, a boundary should continue pushing south of the area with high pressure expected to be centered across the Great Lakes region and Ontario and building into the region. A period of height rises should continue into the start of the period as well. Mid to upper level as well as surface high pressure centered north or northeast of the area is expected to dominate through midweek. The GFS is drier Tuesday into Wednesday compared to the recent ECWMF runs though the 12Z ECMWF has trended drier. With high pressure dominating, generally dry weather is expected for Tuesday into Wednesday though the cap may be weaker near the VA border and a slight chances right along the VA was used each afternoon. Temperatures will be near to slightly above normal on both days with with highs in the 80s on Tuesday and upper 80s to near 90 on Wednesday. Lows will be a bit lower than recent nights on Tuesday night in the mid 60s. The high, however, should move east of the area by late Wed into Wed night, with the boundary that will have stalled south of the area lifting north as a warm front by late Wed and Wed night and leading to increase in dewpoints and humidity. Models continue to indicate a low pressure system moving across central to eastern Canada during the middle to end of the week. An associated cold front should drop south of the Great Lakes and to the OH River on Thursday night. Models continue to indicate the boundary should move south across the area on Friday in advance of a shortwave trough. This boundary should continue to push south of the area Friday night into Saturday. Once the axis of the shortwave trough moves through on Saturday, height rises should occur by the second half of next weekend, with high pressure building toward the area. With the approaching front and shortwave trough more organized convection is expected from Thursday afternoon through Friday evening. Until the shortwave trough axis moves south and east, isolated convection cannot be ruled out over the weekend. Model runs vary with timing this and this will ultimately determine if next weekend ends on a dry note. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 841 PM EDT SUN JUL 23 2017 A broken line of convection has aligned along the Cumberland Valley this evening, but this looks to stay south of the TAF sites. Some isolated convection may threaten the area over the next few hours, and have maintained VCTS. An upper level disturbance will swing through the Ohio Valley tonight, perhaps sustaining some cloud cover. As such, have only allowed for a window of MVFR fog at SME and LOZ. Should more clearing take place, then the potential for more dense fog will increase. Most fog will burn off by 13z, with a return to VFR conditions. Winds will average around 5 kts or less, mainly out of the west southwest. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...KAS LONG TERM...JP AVIATION...GEOGERIAN
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
1054 PM CDT Sun Jul 23 2017 .SHORT TERM...(This evening through Monday) Issued at 312 PM CDT Sun Jul 23 2017 A disturbance across the Tetons will approach the Black hills tonight. The RAP, HRRR and HRRR exp suggest an isolated thunderstorm may affect Pine Ridge. Strong heating and a dryline bulge across Pine Ridge Monday afternoon could spark isolated thunderstorms as suggested by the NAM. The temperature forecast uses blended bias corrected data for lows in the 50s and 60s tonight. The same strategy Monday produces highs into 90s to low 100s. H700mb rise to 12C at North Platte and approach 14C at Valentine where warmest highs will occur. Dry air should keep heat indices below 100 in most areas. .LONG TERM...(Monday night through Sunday) Issued at 312 PM CDT Sun Jul 23 2017 H700mb temperatures Tuesday warm to 13-14C at North Platte and 15C at Valentine. This should support highs of 100 to 105 in these areas. A heat advisory would eventually be needed in some areas. For this forecast it would appear to be generally along and east of highway 83. Outflow dominant storms should fire near or north of the SD late Tuesday afternoon. H500mb winds are about 15kt and the storms will fire along a cold front. The cold front should drift through the forecast area Tuesday night and Wednesday. The SREF was signaling heavy rain and was the fastest model with moisture return. The GFS and NAM are much more modest. The drought could certainly limit rainfall as it has this month in many locations. POPs are 30-50 percent Tuesday night through Wednesday night. Dry and cooler weather should prevail Wednesday through Sunday with northwest flow aloft. The subtropical ridge retreats west into the desert Southwest and h700mb temperature fall to 10-12C supporting highs in the 80s to lower 90s. Rain chances are mostly isolated after Wednesday and none of the models are signaling signficant moisture return. The northwest flow will be strong and back door high pressure will limit moisture return until Friday when a cold front will move through. A second high pressure system moves in Saturday. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1054 PM CDT Sun Jul 23 2017 Mostly clear tonight with lows in the 60s. South winds increase through the day on Monday with gusts to around 20 mph through the afternoon. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION...Power
Area Forecast Discussion
National Weather Service Lake Charles LA
942 PM CDT Sun Jul 23 2017 .UPDATE... Merged regional radar imagery shows that the line of convection that extended across northern Louisiana and northeastern Texas has dissipated just north of the CWA border. Convection has also ended across the CWA with only isolated areas of drizzle remaining late this evening. The latest runs of the of the HRRR and RAP are overdone with regards to convection continuing over central Louisiana and the Texas Lakes region through the next several hours. The consensus of the short term model guidance is that scattered convection could redevelop across areas along and north of US 190 through early morning. Therefore, this update has removed categorical PoPs for southern portions of the region through 3 AM. Otherwise, only minor adjustments to hourly grids were needed to better represent current observations. && .PREV DISCUSSION... /issued 645 PM CDT Sun Jul 23 2017/ AVIATION... Storms near KLCH continue to fall apart this eve as TSTM moves into worked over air fm previous storm earlier. KPOE radar has a weakening line of storms moving down from the north. These storms will move into northern Tyler...Jasper... and Newton counties... and in sw Louisiana northern parishes of Vernon and Rapides. Cloud heights to vary over the next several hours before lifting and falling apart. Overnight storms look to redevelop over the south cntrl La coastal areas. PREV DISCUSSION... /issued 320 PM CDT Sun Jul 23 2017/ SYNOPSIS... Latest Upper air data, water vapor imagery, and LAPS analysis, as of 23/18Z, show a mid level disturbance centered over southwest Mississippi, with shear axis extending westward across the forecast area into eastern Texas. A very humid air mass is also found across the region with subtropical moisture trapped below the shear axis. Surface dew points are in the mid to upper 70s with 23/18Z GPS-MET and LAPS data showing precipitable water values from 2.1 to 2.4 inches and Mean RH over 75 percent. Daytime heating has resulted in the development of clusters of showers and thunderstorms over the forecast area. With very high moisture content, main concern with the convection is potential for torrential downpours with a quick one to two inches of rainfall in a short period of time bringing minor urban type flooding. Also, areas that have seen sunshine and not been worked over from morning convection, are showing CAPE values over 2500 j/kg, so some strong storms are also possible with frequent cloud to ground lightning and downburst winds to over 30 mph. Rua DISCUSSION... Convection is again expected to diminish during the early evening hours with loss of daytime heating. Mid level disturbance is expected to meander around the general region through Monday. Therefore, nocturnal convection is expected to form over the coastal waters late tonight, with some activity reaching the coastline before daybreak, and other nocturnal activity possible late tonight over northern zones closer to center of disturbance. Then activity will develop over land during the late morning into afternoon hours. Expect the best chance and coverage of convection on Monday to be over the northeast and north zones, or in the region closer to the center of the mid level disturbance/shear axis. By Tuesday, the mid level shear axis weakens and gets pushed off to the east. A mid/upper level ridge will then build in its place that will greatly reduce rain chances. The mid/upper level ridge should hold through Friday, with only isolate diurnal convection at best expected. With less convection, more sunshine should be in store resulting in higher daytime temperatures, and with still a south flow at the surface, very muggy conditions. Max afternoon heat index readings are expected to run from 103F 108F degrees, near heat advisory criteria, for Thursday and Friday. A little less confidence for the forecast over the weekend, as differences come about in the possibility of a weak backdoor surface front moving through the forecast area, as upper level trough digs down the east coast. GFS is faster with frontal passage on Saturday, whereas the ECMWF is slower with a frontal passage on Sunday. Unusual for surface fronts to make it through the forecast area at the end of July, so will tend with a slower progression of the frontal boundary, that will call for at-least chance pops on both Saturday into Sunday. Rua MARINE... A weak surface high continues to ridge across the northern Gulf of Mexico and this pattern will persist through the end of the week. Chances for showers and thunderstorms will continue through Monday, before an upper level disturbance weakens and rain chances lower for the remainder of the week. As a result, mainly light onshore flow will continue with relatively low seas. Near any showers or thunderstorms, winds and seas will be locally higher. Rua && .PRELIMINARY POINT TEMPS/POPS... AEX 90 73 91 74 / 60 20 50 20 LCH 86 77 91 78 / 80 20 30 10 LFT 87 76 90 77 / 90 30 40 10 BPT 87 77 91 77 / 70 20 20 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$ PUBLIC...26
Area Forecast Discussion
National Weather Service Medford OR
827 PM PDT Sun Jul 23 2017 .SHORT TERM...An upper low will remain located just off the Northern California coast tonight and Monday. This will bring moisture into the area which combined with instability and forcing will result in showers and thunderstorms. Meanwhile a strong thermal trough at the surface will continue tonight and tomorrow, resulting in strong gusty north winds along the coast in the afternoon and evenings and strong gusty northeast winds over the coastal mountains. Isolated to scattered thunderstorms have developed east of the Cascades this evening and storms occurred earlier over Modoc county. Currently storms are located over far eastern Klamath county and over Lake county. These storms have had gusty winds associated with them along with periods of rain and the potential for small hail. Storms have not developed over the Southern Oregon Cascades. Models continue to show additional showers and thunderstorms possible through tonight east of the Cascades. Showers and thunderstorms may also develop over the Southern Oregon Cascades late tonight. On Monday, models remain on track with scattered storms developing from the Southern Oregon Cascades east and over Modoc county. The GFS and SREF also continue to show a risk for isolated to scattered thunderstorms west of the Cascades, especially in western Siskiyou county and northward into portions of southwest Oregon. The upper low is forecast to remain in place Tuesday, drifting slightly northeast. So expect another day of isolated to scattered thunderstorms. On Wednesday, the low moves inland as an upper trough and shifts eastward. This will result in the focus for thunderstorms becoming more over eastern portions of the area, mainly east of the Cascades. There remains some uncertainty on how much and where storms will develop as this low moves inland though due to model variability on the track and timing of this disturbance as it moves east-northeast. && .AVIATION...24/00Z TAF CYCLE...VFR conditions currently prevail over the area right now, including the waters, and will continue to do so throughout the TAF period. The exception will be along the coast where IFR conditions are expected to return this evening and persist into Monday morning. Isolated thunderstorms have developed over eastern Modoc and southeast Lake counties. Near term models keep thunderstorm activity restricted to this area, progressing it north into Lake county during the evening and diminishing by midnight in this area. However, convection will still be possible overnight, focused along the Cascades. Expect gusty outflow winds in the vicinity of any thunderstorms. Monday will feature more widespread thunderstorm activity. /BR-y && .MARINE...Updated 800 PM PDT Sunday 23 July 2017...A thermal trough will remain near the coast along with offshore high pressure. This combination will produce gusty north winds and steep seas, with gales continuing south of Cape Blanco through Monday night. Very steep and hazardous seas will develop south of Reedsport this evening, expanding to nearly all areas by late tonight. The thermal trough will persist into early next week, though it will weaken Tuesday and Wednesday. Winds will diminish slightly, but seas will remain elevated as fresh swell remains in the area. Hazardous seas and small craft conditions will likely remain in the area through at least Wednesday. /CC && .PREV DISCUSSION... /Issued 227 PM PDT Sun Jul 23 2017/ DISCUSSION...The latest water vapor image clearly shows the upper low off the California coast which has been advertised to happen the last couple of days. The upper low is already tapping into some monsoonal moisture and the result is mid level altocumulus clouds that are moving from south to north into our area. Typically altocumulus clouds are a indicator of increasing instability and moisture and in some cases could be a precursor to thunderstorm activity. PWATS are higher with this mornings sounding showing 1.02 inches. As previously mentioned in earlier discussions, the short range high res HRRR model continues to show first storm development showing up in Alturas County later this afternoon and migrating north into Lake and southeast Klamath County early this evening. This has been consistent with the last several model runs (every hour). Instability will be greatest over the northern Cascades this afternoon. 700mb moisture is not as impressive, but PWATS are expected to increase this afternoon, so still could not rule out isolated storms late this afternoon. The upper flow becoming southeast and this in combination with increasing instability and hotter temperatures will bring an increased risk for at least isolated thunderstorms mid to late Sunday afternoon through Sunday evening. Right now, we think the storms will first develop over the Cascades, Siskiyous and portions of the eastside, then could drift into portions of the westside, including the Rogue, Illinois, Applegate and eastern Douglas County towards Sunday evening. This is because the 700mb flow will be easterly and 700-500mb flow southeast. So we`ll keep a slight chance for these areas, but confidence on exact location of storms in these areas remain low. Meanwhile, the models show greater instability along the northern Cascades Sunday afternoon and expanding south Sunday evening, so the chance for thunderstorms are higher. Confidence is not super high that nothing will happen over the west side where CAPES exceed 1000 J/kg but inhibition should also remain somewhat high. Storms may be quite dry over the east while anything to develop across the west will have much more moisture to work with. Activity tonight should diminish toward midnight but there`s a good chance for isolated storms to continue overnight mainly along the Cascades and portions of the eastside. Of note, SPS lightning progs show a higher probability of 10 strikes stretching west into the Rogue Valley. This looks reasonable given the models are showing some weak shortwaves moving north to northwest around the upper low. Therefore have expanded the slight change coverage to include the Rogue Valley. Elsewhere, we have a slight chance of showers. The models are in general agreement Monday and Tuesday will be the most active days in terms of thunderstorm coverage and chances. The upper low will remain just off the California coast, but it will tap into more moisture on Monday. Instability is still greatest along and east of the Cascades, but there is some evidence portions of the westside, including the Rogue and Illinois Valleys could see more frequent storms. Also there is a better chance for wetting rains as PWATS are expected to increase with a swath of 1+ inches in these areas Monday afternoon. Also winds at 700mb will be lighter, therefore storms could be slow movers. Nocturnal storms again are possible along with lingering overnight showers and some remaining cloud cover Monday night as the upper low slowly moves onshore and multiple shortwaves rotate ahead of it. Right now it`s unclear how the area of storms shapes up, but we could see a fair amount of activity. Tuesday will be another active day with showers and thunderstorms over most of the area as the upper low slowly drifts northeast into Northern California. 700 mb winds are expected to be on the light side (between 5-10 kts) so we`ll once again be dealing with slow moving storms. Moisture is plentiful, therefore the potential for wetting storms are high with locally heavy rain possible where storms are at. The threat for nocturnal storms exist again Tuesday night as the upper low moves over our area. Right now, we think the focus for storms will be over most locations Tuesday evening, then shifting east into Lake and eastern Klamath and Modoc Counties late Tuesday night, but details on this could change, so watch for updates. We do have some lingering thunder chances into Wednesday with wavering confidence on the low actually moving fully out by then. However the latest GFS ensembles mostly support a dry day with storm activity likely off to the east. Dry weather will return Thursday and could last through next weekend. The models have come into agreement showing the ridge building westward into our area in this time period with temperatures heating back up Friday into next weekend with triple digit readings in some inland westside locations and lower to mid 90s east of the Cascades. -Petrucelli FIRE WEATHER...Updated 100 PM Sunday 23 July 2017...The main concern over the next several days continues to be thunderstorms. The current Red Flag Warning will be expanded into more of zone 625 this afternoon. The Watch currently in effect for Monday afternoon and evening will also be expanded in area as well as extended through 18z Tuesday due to forecast nocturnal thunderstorm activity. Finally, a watch as been issued for Tuesday afternoon and evening. The probability and coverage of thunderstorms will peak on Monday evening and Tuesday evening. The increase in instability will be accompanied by an increase in moisture and rainfall with the storms could be near wetting rain. Thunderstorm potential covers a much larger area than described in the Fire Weather Warning/Watch. The area reflects forecasted LALs of 3 or more. The thunderstorm threat will diminish Wednesday afternoon and evening as the upper low moves out to the east of the area and westerly flow develops over the area. This however will likely lead to breezy west winds during the second half on next week. -JRS && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Red Flag Warning until 11 PM PDT this evening for ORZ617-623>625. Red Flag Warning from 11 AM Monday to 11 AM PDT Tuesday for ORZ617-622>625. Fire Weather Watch from Tuesday morning through Tuesday evening for ORZ617>625. CA...Red Flag Warning until 11 PM PDT this evening for CAZ285. Red Flag Warning from 11 AM Monday to 11 AM PDT Tuesday for CAZ284-285. Fire Weather Watch from Tuesday morning through Tuesday evening for CAZ280-281-284-285. Pacific Coastal Waters...Small Craft Advisory until 11 PM PDT Monday for PZZ350-356-370. Gale Warning until 11 PM PDT this evening for PZZ356-376. Hazardous Seas Warning until 11 PM PDT Monday for PZZ350-356-370-376. $$ CC/CC/CC
Area Forecast Discussion
National Weather Service Melbourne FL
916 PM EDT Sun Jul 23 2017 .UPDATE... Tonight...An early start to the convection again today lead to an early finish. The models don`t show any additional precip developing overnight, so will go with a dry forecast. The GFS shows considerable mid/upper level moisture and some convection is forecast in the eastern Gulf of Mexico, so debris cloudiness is not expected to clear out completely. && .AVIATION...VFR expected until Monday when convection initiates again. The HRRR hasn`t been very excited about generating convection yet, but the atmosphere should remain very moist except some drying is shown moving up from the south. The 18z GFS came in a lot drier than the 12z run and lowered POPs across the board. The 00z TAFS showed a lean towards persistence and the local WRF in having VCTS starting 17z inland and 18-19z along the coast, except didn`t include KVRB-KSUA yet. && .MARINE... Tonight-Mon...Atlc ridge axis draped across Lake Okeechobee region will continue to produce a South to southwest flow 10 knots or less, except slightly above 10 knots in the offshore northern waters. Seas have been 1-2 feet nearshore and less than 3 feet offshore. The models show a continuance of lower storm coverage Mon afternoon, but a few should be strong again. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ Forecasts...Lascody Radar/Impact Wx...Combs/Weitlich
Area Forecast Discussion
National Weather Service Mobile AL
708 PM CDT Sun Jul 23 2017 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION... 24/00Z issuance...Isolated SHRA/TSRA this evening along the coast and over the coastal waters, but generally VFR conditions at terminals with VCTS overnight. Toward sunrise Sunday and through much of Sunday morning, expect periods of SHRA/TSRA over southern half of the forecast area, with occasional IFR conditions in and near convection. Surface winds generally southwest at 6 to 8 knots or less overnight, then around 8 to 12 knots during the day on Sunday. 12/DS && .PREV DISCUSSION... /issued 402 PM CDT Sun Jul 23 2017/ NEAR TERM /Now Through Monday/...A broad upper level trough continues to extend from southwest MS through much of LA and into southeastern TX this afternoon, while another weak trough was located in the vicinity of southern GA and northern FL. An axis of moisture extended across much of this region, including central and southern portions of our CWA, where precipitable water values may be ranging between 2.0" and 2.25". Despite this presence of deep layer moisture, overall convective coverage has been low-end scattered at best across the region so far this afternoon. Still some opportunity for additional development across the region through the rest of the afternoon, so will leave chance POPs in place through 00Z. Convection should gradually diminish in coverage over inland areas through the early to mid evening hours. However, high resolution and deterministic model guidance is in agreement that showers and storms will once again re-develop between 06-12Z over southern/coastal portions of the forecast area. The past couple of HRRR runs favors a wet forecast south of a Wiggins to Crestview lines overnight, and a look at the consensus on MOS guidance also lends confidence to trend POPs up a bit to 30-40% overnight south of this line. Little change in overnight lows is expected, with readings in the lower to mid 70s inland, with mid to upper 70s generally anticipated along the immediate coast and beaches. Broad upper troughing will continue to extend from southeast TX through MS/AL during the day Monday, and a very moist airmass will remain in place across our forecast area near this feature, with precipitable water values as high as 2.25". We expect better coverage of showers and thunderstorms to develop inland through Monday afternoon, and will continue to carry likely POPs (60-70%) over most of the area. Highs Monday afternoon will average in the upper 80s to around 90 across the region. /21 SHORT TERM /Monday night Through Wednesday night/...Subtle differences in the synoptic scale in the handling of an upper trough over the Lower Mississippi River. The GFS shifts the axis of the trough quickly southeast, quickly putting the majority of the forecast area under an area of subsidence on the west side of the trough. The NAM and ECMWF shift the trough slowly east, keeping the forecast area under more favorable upper support longer. This results in an upper ridge centered over the Four Corners region building farther east quicker over the Southern Plains and a quicker drying out along with rise in temps. The NAM and ECMWF solutions, with their slower movement of the upper trough, result in a cooler, wetter forecast through mid week. With the 00z GFS ensemble MOS also hinting at a wetter forecast, have leaned towards the NAM and ECMWF for the final solution. THe result is a chance of rain above seasonal(scattered to likely during the day with scattered overnight) into Wednesday, then transitioning to around seasonal (isolated at night with scattered during the day) for Wednesday/Wednesday night. Temps transition from a tighter than seasonal diurnal temp range (upper 80s to around 90 during the day to low to mid 70s overnight) to a bit above seasonal for Wednesday as the upper trough moves east of the forecast area, but the airmass remains seasonably soupy. Highs and lows a bit above seasonal expected as the Plains ridge begins to nose east over the Lower Mississippi River Valley. Highs in the low 90s, lows in the low to mid 70s expected. /16 LONG TERM /Thursday Through Sunday/...A temporary return of seasonal rain chances returns for Thursday into Friday, but guidance is advertising a shortwave diving into the now over the East coast upper trough Friday into friday night, with another Saturday into Sunday. The GFS is advertising this energy deepening the eastern upper trough than the ECMWF, which allows the Plains ridge to build southeast over the Western Gulf of Mexico. With inconsistent timing/path/strength, have went with a blended approach. Result is temps a bit above seasonal for Thursday transitioning to below seasonal for the weekend with a chance of rain transitioning from a bit below seasonal to around seasonal for the weekend. /16 MARINE...Additional scattered to numerous showers and thunderstorms are expected to re-develop over the marine area again late tonight into Monday morning, and the pattern of mainly nighttime and morning showers/storms will continue into midweek. Southwesterly to westerly winds otherwise increase to 10-15 knots, with seas building to 2 to 3 feet through the middle part of the week. /21 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...None. FL...None. MS...None. GM...None. && $$ This product is also available on the web at: http://weather.gov/mob
Area Forecast Discussion
National Weather Service Nashville TN
854 PM CDT Sun Jul 23 2017 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Some storms continue east of I-65 with an upper impulse that is sweeping through the area. These storms are not as intense as they were a couple hours ago. Still can`t rule out a gusty storm over the next hour. HRRR has consistently shown this activity will continue to decrease over the next few hours. Pops were adjusted down west of I-65 and north of I-40 where the atmosphere has not recovered from earlier storms. Only other changes to the forecast were hourly adjustments to temperatures and dew points. && .AVIATION... 18Z TAF DISCUSSION. Upper level impulse will approach from the northwest by late this afternoon. pva enhancement over the middle TN area will lead to an increase in shower and tstm activity by 00z. Will include vcts and prob 30`s to cover the convection. Activity not quite expected to be widespread enough to warrant tempo. Rainfall chances will diminish after 06z with fog vsbys dropping to as low as 3-5sm late. Look for partial haze during the 12z-18z timeframe. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......Reagan AVIATION........Shamburger
Area Forecast Discussion
National Weather Service Pueblo CO
757 PM MDT Sun Jul 23 2017 .UPDATE... Issued at 757 PM MDT Sun Jul 23 2017 Updated forecast based on radar coverage. && .SHORT TERM...(This evening through Monday) Issued at 255 PM MDT Sun Jul 23 2017 Monsoon plume still resides over the region though layer specific humidity values are lower than the past couple days, particularly across northern and eastern portions of the area. Still enough moisture present however for diurnally driven convection which is what models portray. Doesn`t appear to be much forcing today...though area of cloudiness in the San Luis Valley and Southwest mountains appear to be related to an upper level shear axis around southern side of the upper high. So expect evening thunderstorms to be confined mainly to the mountain areas today with weak north to northeasterly and even easterly steering currents generally keeping convection over the mountains. The hrrr runs suggest an isolated thunderstorm or two could develop over the Palmer Divide this afternoon as well so will keep some isolated pops across that area as well. Elsewhere across the plains looks dry. Mtn convection should wind down this evening with some lingering showers possible across the southwest mountains overnight in proximity to deeper moisture associated with the monsoon plume. Monday looks similar to today, though a few degrees warmer. Once again mountains and adjacent I-25 corridor will see the best chance for TSRA. Layer specific humidities increase a bit across the southwest mountains so this area will be most at risk for heavy rain produced flash flooding. But certainly all storms both today and Monday will carry that risk should they impact burn scars, urban areas or locations with saturated soils. -KT .LONG TERM...(Monday night through Sunday) Issued at 255 PM MDT Sun Jul 23 2017 No big changes to ongoing forecast with weak west to southwest flow aloft remaining across the area Monday night and Tuesday, as the upper high across the region continues to build south and east into the Southern High Plains. Monsoonal moisture continues to work back into the state through the period, leading to increasing chances of afternoon and evening showers and storms, especially across the western half of the area. The latest models are also indicating a weak disturbance moving across the Great Basin Monday night, which could keep showers and storms going through early Tuesday morning, especially along and west of the ContDvd. The increasing moisture and weak steering flow aloft will continue to support locally heavy rainfall and the potential for flash flooding, especially over and near area burn scars. Temperatures across the area are expected to be near to slightly above seasonal levels, especially across the eastern plains. A more active period across all of south central and southeast Colorado remains on tap for the Wednesday through Thursday timeframe, as a minor disturbance moving across the northern fringe of the high across the Northern Rockies sends a cold front across the eastern plains through the day Wednesday. The front will be a focus for convection across the eastern plains on Wednesday, with moist low level upslope expected to persist through the day on Thursday. This, along with the monsoonal plume across the area, will lead to widespread afternoon and evening showers and storms with the greatest coverage expected to be over and near the higher terrain. Again, the main storm threats will be locally heavy rainfall and the potential for flash flooding, though cant rule out gusty outflow winds and small hail throughout the period. With the expected increase in convection, temperatures look to cool to below seasonal levels, especially across the eastern plains. There looks to be a slow warming and drying trend for the end of the work week and into next weekend, as monsoonal moisture gets shunted south and west of the area the upper high again retrogrades into the Desert Southwest. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 255 PM MDT Sun Jul 23 2017 Scattered thunderstorms will continue into the evening hours with an isolated storm or two possible across El Paso county. Main threat with thunderstorms with be brief MVFR conditions along with erratic wind gusts up to 40 kts. KALS will see the highest chance for -TSRA to occur at the terminal, with KCOS seeing a less likely VCTS possibility. KPUB will see the lowest probability for thunderstorms so will keep that TAF site dry. Best chance will be before 02z...then skies will clear out overnight. Will carry VCSH in at KALS until 05z as this area will be under the richer monsoon moisture plume. Monday looks similar to today with most thunderstorms tied to the mountains. There is a slightly better chance for one or two to drift off into the adjacent plains during the late afternoon and evening affecting the KCOS and KPUB taf sites. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MW SHORT TERM...KT LONG TERM...MW AVIATION...KT
Area Forecast Discussion
National Weather Service Blacksburg VA
912 PM EDT Sun Jul 23 2017 .SYNOPSIS... A slow-moving cold front will drift southward over the Mid Atlantic during tonight into Monday. This frontal boundary will stall and eventually head back north as a warm front later in the week. && .NEAR TERM /THROUGH MONDAY/... As of 910 PM EDT Sunday... Ill defined weak frontal boundary being pushed along by shortwave energy aloft is helping to trigger convection in a pool of residual instability extending from far southwest Virginia back through Tennessee. HRRR meso guidance has been handling the situation quite well and will lean heavily on it to structure POPs overnight. Expect the showers and thunderstorms to spread eastward early tonight, then fade after crossing the Blue Ridge after Midnight. The threat for severe weather will be quite low and rely on outflow boundary interactions in clusters of storms. Lows tonight will remain warm with low/mid 70s east of the Ridge and mid/upper 60s west. Previous discussion... Chances of showers and thunderstorms appear lower for Monday afternoon, and any activity that does develop will be isolated at most. The best chances for any development appear to be in the northwest North Carolina mountains. Most locations should remain dry on Monday, but it will be hot and humid once again by the afternoon. Roanoke will more than likely reach its 15th consecutive day of having a high temperature of 90+ degrees on Monday. At that point, this streak would take sole possession of fifth place for the all-time longest streak of 90+ degrees since records began in 1912. However, this streak would have to reach 22 consecutive days to tie the longest streak on record that occurred during June 23rd through July 14th back in 1966. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... As of 300 PM EDT Sunday... Upper trough over the Northeast at the outset of this period will be lifting out with a trailing cold front stretching from just off the Atlantic coast back though central VA. This front is expected to make progress to the south and east over the ensuing 24-hour period reaching to about South Carolina where it is expected to stall out. The surface high over the Great Lakes will also slide toward the east and should usher in a slightly drier and cooler air mass into the region. Did not go quite as aggressive as the model blend in lowering dewpoints but possibly a 3 to 5 degree F drop by Tuesday night into early Wednesday, which should be noticeable. Overnight lows Monday range from low 60s NW to low 70s SE. Highs Tuesday near climo norms for late July l/m 80s NW and low 90s SE. Chances for rainfall will be low with the only PoPs at slight or higher compressed to the far southern reaches of the CWA where somewhat better moisture/instability will reside. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 1100 AM EDT Sunday... Wind flow around high pressure centered over New England will result in an easterly breeze on Wednesday, bringing cooler Atlantic air into the region. As such, afternoon high temperatures will likely be the coolest of any day this week, ranging from the mid/upper 70s west to low/mid 80s east. The upslope wind flow will also support spotty showers/thunderstorms during the afternoon and evening, with greater coverage across the mountains and foothills. High pressure will shift off the New England coast Wednesday night, allowing winds to turn more southerly across the mid- Atlantic by Thursday, making for a return of warmer, more humid air. Strong daytime heating will support pulse variety showers and thunderstorms, a few of which will likely become strong for brief periods of time during the afternoon and evening. A cold front will make its way across the mid Atlantic on Friday, triggering more organized/widespread shower and thunderstorm activity. Latest run of the weather forecast models indicate that the front will clear our area to the south by Saturday morning, bringing drier air in its wake. Have therefore lowered rain chances for next weekend, though isolated showers/storms cannot be ruled out. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... As of 735 PM EDT Sunday... The main short wave associated with the upper trough moving slowly across the Great Lakes was moving into the CWA from the west this evening, triggering another more significant round of convection. Following the HRRR and other short range/HIRES models, would expect convection to track into far southwest VA/southern WV over the next few hours before dissipating toward midnight near the Blue Ridge. Will include VCTS at BLF and BCB and VCSH at LWB/ROA until better expectation of how far thunder will go before including further east. Expect mostly VFR ceilings, except brief basically unpredictable MVFR-IFR ceilings in evening thunderstorms. Overnight, upslope westerly flow behind the upper trough should result in MVFR cigs developing from LWB to BLF and possibly BCB as well, breaking up and becoming scattered 14Z-15Z with VFR expected the rest of the day. Confidence in any convection Monday afternoon is too low to include in the TAFs at this time. Have not included fog at this time because of cloud cover, wind, and precipitation expected overnight. Will need to watch across the Piedmont. Winds will remain WSW-WNW 5-10kts through most of the TAF valid period, but low end gusts are expected after 14Z Monday mainly west of the Blue Ridge. Medium confidence in ceilings through the TAF valid period. Medium to high confidence in visibilities through the TAF valid period. High confidence in wind speed/direction through the TAF valid period. Aviation Extended Discussion... A slow-moving cold front should slowly sag south of our region by Monday afternoon into Monday night. This frontal boundary should stall to the south by Tuesday and eventually return northward as a cold front later in the week. Although convection should become more isolated for most of this period, the weather patten will still remain unsettled to some extent. High pressure wedging southward on Wednesday could bring some MVFR/IFR ceilings, which should quickly vanish by Thursday. Aside from any early morning fog and isolated convection, VFR conditions should prevail through most of this week. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PW NEAR TERM...MBS/RAB SHORT TERM...WP LONG TERM...NF AVIATION...PW/RAB
Area Forecast Discussion
National Weather Service Las Vegas NV
105 PM PDT Sun Jul 23 2017 .SYNOPSIS...Wet weather pattern is expected to begin developing tonight as a significant push of monsoon moisture spreads northward across the area. Periods of showers and storms can be expected across much of the area tonight through Tuesday night, especially across northwest Arizona and southern Nevada, before a drying trend begins mid to late this week. && .SHORT TERM...Today through Tuesday Convection is slow to get going this afternoon but starting to see some better organized activity across the southern Great Basin. A couple showers are also underway near the Spring and Hualapai mountains. Continued destabilization should result in activity increasing later this afternoon, with most widespread activity across Lincoln and central Nye counties. By this evening, attention will shift to more robust activity across Northern Arizona which will gradually drift westward through the overnight. Some of this activity will have the potential for very heavy rainfall given Precipitable Water Values of 1.25-1.75 creeping northward. Given the relatively slow storm motion and anomalous moisture, went ahead with a Flash Flood Watch for Mohave county through the night. In fact, latest runs of the HRRR break out widespread convection across Mohave county and far eastern San Bern county after midnight, and this seems reasonable given an approaching wave moving in from Arizona. Tomorrow the moisture will surge northwestward across Southern Nevada and Eastern California, with near record Precipitable water values pushing into the region. Was inclined to issue a Flash Flood Watch for far southern Nevada and Eastern San Bern county, but considering potential sky cover issues and coordination with the AZ offices, have held of for now. One feature of note is the GFS brings a vort max northward up the Colorado River valley tomorrow, reaching near Lake Mead by tomorrow evening. This could be a focus of convection tomorrow, and if we can get enough daytime heating in advance of this feature, exceptionally heavy rainfall will be a possibility. Alternatively, if we wake up to abundant clouds, we may have a hard time generating strong convection and hence, we`d have a reduced flash flood threat. Shower and thunderstorm activity will tend to lift north tomorrow night but it will remain fairly moist and unstable across southern Nevada and far northern Arizona well into Tuesday. Stay tuned for the possibility of additional Flash Flood Watch issuance`s and be prepared for locally heavy rainfall with any thunderstorm activity that develops over the coming days. Just keep in mind the convective evolution will be highly dependent on cloud cover trends. In addition to the rain chances, increased clouds will work to keep temperatures below normal for the eastern two- thirds of the forecast area Monday through Wednesday. .LONG TERM...Wednesday through Saturday. Gradual drying and warming is expected for the Wednesday and Thursday as weak southwest flow returns to the region. Enough moisture is likely to remain in place for afternoon showers/storms over favored high terrain. By Friday, high pressure once again pushes back to a favorable location near the Four Corners, allowing for a moist southeasterly flow into the region. However, this is where guidance begins to diverge, with the GFS keeping the high and favorable flow well into the weekend while the ECMWF is significantly different, pushing the high to near Reno and keeping much of the moisture to the south of Las Vegas. For now I`ve split the difference, increasing dew points, and PoPs over the area, but with a emphasis on areas south of Las Vegas. && .FIRE WEATHER...Isolated thunderstorms will again be possible today, mainly across the Sierra...Southern Great Basin...and Northwest Arizona. A stray storm or two can be expected in the Spring and Sheep range as well. An influx of moisture will arrive tonight and tomorrow across Southern NEvada and far eastern California, resulting in an increase in humidity and cloud cover, and better chances for thunderstorms with wetting rains. Conditions will gradually dry out midweek onward, with thunderstorms decreasing in coverage each day. Temperatures will be near normal to somewhat below normal through Wednesday, before returning to slightly above normal late in the week. && .HYDROLOGY... Creeks, streams and rivers in northern Inyo County have shown decreasing flows over the last couple of days. However, some road closures continue in the area. Bishop Creek Bypass and Big Pine Creek Bypass continue to be utilized to minimize flows through Bishop and Big Pine. Remember, never drive through flooded roadways or around barricades. Also, pastureland or farmland adjacent to creeks, streams or rivers could experience areas of standing water. && .AVIATION...For McCarran...East to southeast winds under 10 knots are expected through early this evening. Confidence in winds later this evening and overnight is low. They may try to trend toward typical night time south/southwest drainage at 10 knots or less but several forecast models are indicating potential for a stronger push of southeast winds due to thunderstorms over northwest Arizona for the late evening hours. Mainly southeast winds around 10 knots are expected Monday. Thunderstorm chances will be increasing in the Las Vegas Valley Monday with a chance of storms at the terminal mainly Monday afternoon and evening. Cigs with storms could drop to 5 kft briefly with stronger storms. Otherwise cigs will mainly be AOA 10 kft. For the rest of southern Nevada, northwest Arizona and southeast California...Most areas will see south to southeast winds 5-15 knots through Monday. Showers and storms are expected across Mohave and Lincoln counties once again along with the higher elevations of Clark County and the southern Sierra through this evening. Overnight storms will be possible tonight into early Monday mainly across southern Mohave, and southeast San Bernardino counties. Gusty and erratic winds can be expected near any thunderstorms. Thunderstorm chances will spread across the entire area as the day progresses Monday. Cigs with stronger storms could drop to around 5 kft. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather and especially flood impacts the next several days as an active monsoon pattern unfolds. && $$ SHORT TERM/FIRE WEATHER...Outler LONG TERM....Wolcott AVIATION...Harrison For more forecast information...see us on our webpage: http://weather.gov/lasvegas or follow us on Facebook and Twitter