Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/16/17

Area Forecast Discussion
National Weather Service La Crosse WI
859 PM CDT Thu Jun 15 2017 .UPDATE... Issued at 859 PM CDT Thu Jun 15 2017 Thunderstorms will continue to drift south and eventually away from Chickasaw, Fayette, Clayton, and Grant Counties through 11 PM. Most of the MLCAPE has now pushed south of the forecast area and with the thicker anvil and boundary pushing south across northeast Iowa into far southwest Wisconsin, not expecting much more activity outside of a stray shower or isolated thunderstorm. It appears the severe weather threat has just about ended. Will be holding onto the severe thunderstorm watch just a little bit longer until the last batch of storms in Bremer and Buchanan County in northeast Iowa weaken or shift well to the south. The severe thunderstorm watch will likely be cancelled well before 1 AM for the La Crosse Forecast Area. && .SHORT TERM...(This evening through Friday) Issued at 225 PM CDT Thu Jun 15 2017 At 3 PM, a weak boundary was located across central Iowa. Dew points north of this boundary were in the lower and mid 50s and around 60F south of it. The HRRR and RAP suggest this boundary will slip northeast into northeast Iowa this afternoon and early evening. As this occurs, the mean layer CAPES are forecast to climb into the 500 to 1500 J/kg range. In addition, a 500 to 700 mb speed max will increase the effective wind shear up to 60 knots. While the hodograph is favorable for splitting supercells, any left movers will move quickly into a drier environment, so their impact will be limited. Due to this, the SPC 1630Z Day 1 Convective Outlook moved the marginal risk up to the Interstate 90 corridor and the slight risk into northeast Iowa and a small portion of southwest Wisconsin. This risk is a very conditional and highly dependent upon our dew points getting as high as what the CAM models indicate (around 60F). If convection can develop, the main severe weather threats would be large hail and damaging wind (primarily based on the strong winds aloft and inverted V in the sub-cloud layer). From late Friday morning into Friday afternoon, another short wave trough will move east through the region. The 0-1 km mean layer CAPES climb into the 500 to 1000 J/kg range. While the deep layer shear is not that impressive, the 0-3 km shear does get into the 25 to 35 knot range and there is an inverted V in the sub- cloud layer, so maybe an isolated wind threat. .LONG TERM...(Friday night through Thursday) Issued at 225 PM CDT Thu Jun 15 2017 On Friday night, it continues to look like a mesoscale convective complex will develop in western Iowa on the northern edge of an unstable air mass (2-4K J/kg) in southwest Iowa. This system will then track either southeast through southeast Iowa and northern Illinois or dive south into the Ozarks. In either scenario, this would push the front across Iowa much further south. This has been a trend in the GFS, ECMWF, and GEM. If this does indeed occur, the threat of severe weather for Saturday afternoon and night will likely to shift further south. Even if this does occurs, the combination of a coupled jet and strong short wave trough will still produce showers and scattered storms across the Upper Mississippi River Valley for Saturday afternoon and night. On Sunday, wrap around moisture and cold air aloft will result in the development scattered showers and isolated thunderstorms. Strong cold air advection in the wake of this system will bring much colder air into the region. Temperatures on Sunday and Monday will range from the upper 60s to mid 70s and then slowly moderate as we move into mid week. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 703 PM CDT Thu Jun 15 2017 VFR conditions are expected through the TAF period. Thunderstorms are expected to remain well south of the TAF sites this evening, across northeast Iowa and extreme southwest Wisconsin. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ UPDATE...Wetenkamp SHORT TERM...Boyne LONG TERM...Boyne AVIATION...Wetenkamp
Area Forecast Discussion
National Weather Service Denver/Boulder CO
849 PM MDT Thu Jun 15 2017 .UPDATE... Issued at 849 PM MDT Thu Jun 15 2017 A few echoes showing up on radar over Weld County this evening, but don`t believe much if anything is reaching the ground. High and mid level clouds are increasing, with the CIRA Simulated WRF showing some possible wave clouds later tonight between 08-12Z. Added some additional sky cover to account for this. This may keep lows near the southern foothills warmer than what we already have in there, but will keep what is forecasted just in case they are thinner. Also did minor adjustments to high temperatures tomorrow, mainly in the high country after we warmed up a degree or two over today`s forecasted highs. && .SHORT TERM...(This evening through Friday) Issued at 343 PM MDT Thu Jun 15 2017 Warm dry air moving over Colorado in westerly flow aloft. There will be bands of high clouds, mainly over the northern part of the state, and some high-based afternoon cumulus clouds. Temperatures should warm a little more on Friday despite a bit more cloud cover. The only changes to the existing forecast were to add a little more cloud cover and a little more wind for the mountains. With a little more wind and heat Friday and slightly lower humidities, there will be a few areas approaching Red Flag criteria. This is mainly over the east slopes in places like Fairplay and Georgetown that are prone to winds descending from the higher mountains. With marginal conditions as well as marginal fuel moisture we will not issue a warning. .LONG TERM...(Friday night through Thursday) Issued at 343 PM MDT Thu Jun 15 2017 A short wave trough embedded in the strong westerly flow will race across the Northern Rockies and Northern Plains Friday night and Saturday. Over Colorado, a weak west-northwest flow aloft will prevail. A cold front will enter northeast Colorado late Saturday morning and dive south through the state during the afternoon and evening. Expect temperatures to stay steady or fall a little behind the front Saturday afternoon, so the timing of the front will affect high temperatures Saturday. Southern areas of the forecast area will approach 90. Northern areas will cool off sooner and expect lower 80s for highs. Moisture increases behind the front with precipitable water values around an inch during the late afternoon and evening over northeast Colorado. The increase in moisture and northeast upslope flow behind the front is expected to produce isolated thunderstorms. The lack of large scale forcing and the warm air aloft will likely limit storm coverage to isolated. Sunday will be the cooler with highs in the 80s. Even though there will be some moisture around on Sunday. A strongly capped airmass will prevent showers/thunderstorms from forming. Temperatures will warm next week as an upper level ridge builds over the southwest part of the country. For Tuesday and Wednesday, high temperatures are expected to be in the 90s. The ridges shifts south, which may allow slightly cooler air into the area Thursday, though highs will still be above normal with upper 80s to mid 90s expected. Tough to tell if there will be enough moisture for afternoon/evening thunderstorms. Models hint at isolated convection Wednesday and Thursday, so will have low pops in the forecast. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 849 PM MDT Thu Jun 15 2017 VFR through Friday with ceilings above 12kft AGL. Winds in the Denver area are taking slightly longer to transition to normal S/W drainage winds. RAP and HRRR showing this will likely happen between 04z and 06z now. Winds are expected to veer to the NW Friday after 15Z. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Kriederman SHORT TERM...Gimmestad LONG TERM...Meier AVIATION...Kriederman
Area Forecast Discussion
National Weather Service Burlington VT
930 PM EDT Thu Jun 15 2017 .SYNOPSIS... High pressure across the Gulf of Maine early this afternoon will exit south of Nova Scotia this evening. An upstream warm front and mid-level trough across western New York will bring increasing clouds and periods of showers overnight into the day Friday across northern New York and Vermont. Clouds will generally keep temperatures in the 60s Friday afternoon. Thereafter, increasing south to southwest flow will result in building heat and humidity for the weekend, with highs in the mid 80s on Saturday, and upper 80s to lower 90s on Sunday. Isolated thunderstorms are possible both days. An approaching cold front will bring the threat for strong to locally severe thunderstorms on Monday, along with locally heavy rainfall with very moist air mass in place ahead of the front. && .NEAR TERM /THROUGH FRIDAY NIGHT/... As of 930 PM EDT Thursday...Additional updates to massage pops in closer agreement with latest HRRR output which has finally begun to show current rainfall trends across northern NY somewhat closer to reality. Still expecting majority of showers to occur across northern NY through midnight, thereafter spreading across central and northern VT into the overnight and pre-dawn hours. Did opt to raise minimum temperatures slightly in the Champlain Valley where increasing south to southwesterly flow in the lower levels will foster increasing dewpoints and warm advective processes overnight. Prior discussion... Shortwave trough crosses the Champlain Valley and nrn VT during Friday morning, with additional showers producing up to 0.25" additional rainfall. Best forcing shifts east aftn/evening hrs, so should see diminishing PoPs but with lingering stratus/stratocu Friday aftn. Right now, appears cloud cover limits heating with highs only in the 60s, except lower 70s across the St. Lawrence Valley. Will need to monitor as additional sunshine late may allow temps to warm more than currently indicated. Deep-layer south to southwest flow in place Friday night, but in the absence of much convergence/low-level forcing. Should be relatively quiet with variably cloudy conditions as any lingering -SHRA exit ern VT during the early evening period. Lows Friday night generally lower 60s across the Champlain and St. Lawrence Valleys, and 55-60F elsewhere across the CWA. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... As of 330 PM EDT Thursday...Warm front pushes across our forecast area from West to East on Saturday and temperatures will warm into the 80s across our forecast area. Upper level ridge builds over our forecast area and 850 temps will reach the upper teens supporting these high temps. There will be a chance for some showers especially in the higher terrain with weak shortwave energy passing overhead. A little bit of CAPE squeezes into the Dacks and SLV so have continued with mention of some thunder for Saturday afternoon. Warm air advection will continue Saturday night and a mild night is on tap with mins only dipping into the 60s to low 70s. Clouds with a chance for some showers continues overnight. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 345 PM EDT Thursday...Sunday and Monday will be an active period of weather with showers and thunderstorms expected Sunday and especially Monday with locally heavy rainfall possible with a slow moving cold front. Sunday will be another very warm day with continued warm air advection and 850 temps warming to almost 20C. Temperatures will warm in the mid 80s to lower 90s. Surface low pressure system lifts from the Northern Great Lakes to near James Bay by 00z Monday. Timing of cold front will still be critical for potential for strong convective storms and severe potential. Temperatures will warm into the mid 80s ahead of the cold fropa especially across our Eastern zones. It continues to look like some heavy rainers are possible with pwats up around 2", but lack of rainfall the past couple weeks may limit flash flood potential. Forecasters will continue to monitor potential for both severe thunderstorms and flash flooding with this system. The ECMWF is still a bit faster than the GFS with timing of cold front on Monday. The GFS would support potential for some stronger convection. Upper trof will lag behind the surface front and keep some showers in the area for Tuesday as well. The models diverge a bit beyond that feature, but it looks like the weather will remain pretty active through mid week. Temperatures will trend back towards seasonal normals for the end of the week. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Through 00Z Saturday...VFR conditions are in the forecast for the next 24 hours though confidence in remaining VFR through the entire period is low. Models having a very hard time handling convective activity upstream and subsequently spread MVFR cigs into the North Country overnight and into Friday. Based on current satellite and radar trends though, feel this is very overdone so have played a more optimistic card. Still will likely see some light showers around through the period, but flight restrictions should be limited. Higher confidence in winds where variable at 5-10kts this evening increase overnight with sustained winds 10-12kts or so, and gusts 20-22kts at KPBG/KBTV during Friday morning with increasing gradient flow. Outlook... Friday Night: VFR. Slight Chance SHRA...Patchy FG. Saturday: VFR. Chance SHRA...Slight Chance TSRA. Saturday Night: VFR. Slight Chance SHRA...Slight Chance TSRA. Sunday: VFR. Chance SHRA...Slight Chance TSRA. Sunday Night: VFR. Chance SHRA...Slight Chance TSRA. Monday: VFR/MVFR. Likely SHRA...Likely TSRA. Monday Night: VFR. Chance SHRA. Tuesday: VFR. Chance SHRA...Slight Chance TSRA. && .MARINE... Increasing southerly gradient winds will reach the 15-25kt range (and Lake Wind Advisory criteria) beginning around 06Z Friday. Winds peak at 20-30kts around daybreak Friday with southerly low-level jet in place over Lake Champlain. Will see winds gradually decrease during the daylight hours Friday. Waves should peak 3-4ft across the northern end of the broad lake during Friday morning. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Banacos NEAR TERM...JMG/Banacos SHORT TERM...Neiles LONG TERM...Neiles AVIATION...Lahiff MARINE...Banacos
Area Forecast Discussion
National Weather Service State College PA
1057 PM EDT Thu Jun 15 2017 .SYNOPSIS... A warm front will move north of the area overnight. This will keep the mention of showers and thunderstorms in the forecast into the weekend. A cold front will push through early next week and lower the humidity and temperatures for the middle of next week. && .NEAR TERM /THROUGH FRIDAY/... The line of heavy rain and thunderstorms that moved into the Central Mountains has transitioned into a general area of moderate to heavy rain with just some embedded thunderstorms. The HRRR after significant having run to run inconsistencies seems to be settling into a solution where the showers continue to move across and begin to become less organized as we move into early Friday morning. Additional showers moving into Somerset and Cambria counties will move over rain soaked grounds so a new Flood Advisory was issued for that area. The heaviest rains have fallen, but areas that got hit hard earlier could warrant additional flood headlines depending on the evolution of the new convection moving through my SWRN zones, Another muggy night is in store with temperatures and dewpoints in the low to mid 60s. && .SHORT TERM /FRIDAY NIGHT THROUGH 6 PM FRIDAY/... Showers/storms are more than likely tonight for most of the area. The SE may continue to stay dry all night. The threat for heavy rain is greatest tonight when the deep moisture plume gets farther into the area. Thus far, it has remained to our west. The 1.5+" PWATs will be in place and there will be a period of time this evening and early tonight when the relative inflow of moisture will match/balance the storm motion. This can lead to heavy rainers. But, with no specific locations primed with very wet soil, still some time to go, and some uncertainty of where heavy rain is most likely, no flash flood watch will be issued on this shift. The day shift will have a better look at it as the meso models/CAMs begin to reach into that time frame. At this point, the NAM drops point amounts of 2+" QPF in the W and NC mtns. The GFS is lower and more washed out on the QPF amounts. Will hold basin-average QPF to around an inch total in the west and NC mtns. Will continue to mention heavy rain in the wx grids. The most potent trough aloft will be off to the east by sunrise, and forcing wanes. But, lingering boundaries could be foci for SHRA/TSRA on Fri. The LI`s don`t get negative in the northeast on Fri per the NAM and GFS, but dewpoints still high in the east and south, and the CAPE is again progged to be above 1000joules. Will continue to mention thunder with the entire area in general thunder on the SPC Day2 prog. Expect temps to be a little warmer on Friday in the west where it may dry out in the afternoon. The sparse coverage of showers/storms on Friday should preclude any further worries of flooding. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... Model and ensemble guidance remain in good agreement on the development of a modestly strong mid/upper level trough over the Great Lakes by Monday, with multiple waves progressing around the base of the trough and ejecting northeast into Canada. The most likely period for showers and thunderstorms (Sun-Mon) will focus along the associated surface cold front which is progged to slowly push southeast and reach the Mid Atlantic coast by 20/12z. Precipitation will be focused mainly to the west of the Appalachians on Sunday before shifting east on Monday. Temperatures are fcst to trend above average over the weekend with max readings in the mid 80s to low 90s on Sunday. Max heat index is projected to reach the mid/upper 90s across portions of the mid- lower Susquehanna Valley. Unlike the recent heat episode, the duration of hot temperatures will be shorter and last 2 days at most (limited area-SEPA). Lower humidity and near average temperatures are likely following the cold frontal passage into the middle part of next week. Another shortwave is fcst to rotate through the trough around midweek before the upper level pattern turns more zonal by the end of next week. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... The Thunderstorms have all but ended, though rumble is possible along a cluster moving over the Laurels. Showers continue across most of central PA. Cigs have already begun to slowly deteriorate as BFD, JST and AOO are experiencing periods of IFR cigs and VSBYS. Deteriorating cigs will spread over the Western and central TAF sites tonight. The moist southeast flow coupled with rainfall from earlier today, and residual showers affect the region. Expect IFR cigs at times at BFD, JST AOO and UNV to be possible until Friday morning. Conditions will slowly improve, with JST and BFD probably holding onto restricting conditions until around 15Z. Another round of showers and thunderstorms is possible late tomorrow morning. .OUTLOOK... Fri...Low cigs, showers/tstorms possible, mainly in the AM. Sat...AM fog possible. Sun...Patchy AM fog poss east. PM tsra impacts poss west. Mon and Tue...Tsra impacts possible. && .CTP WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch until midnight EDT tonight for PAZ004>006- 010>012-017-018-024-025-033-034. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...Dangelo/Gartner LONG TERM...Steinbugl AVIATION...Ceru/Gartner
Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
910 PM CDT Thu Jun 15 2017 .UPDATE... Minor adjustment to raise convective chances out west into the chance category, as cluster of strong to severe storms near Abilene continue to their march south-east along and just west of the Colorado River Valley, along a strong instability axis. Though CIN continues to increase with nightfall, cannot rule out some scattered coverage S of I-20 and west of U.S. 281 from Stephenville to Lampasas. Nothing severe, as this complex will encounter a more stable and drier mid level environment to it`s east with time through midnight CDT. Cannot rule out some very gusty winds with very warm conditions below the EML, but nothing severe is expected across our western counties. 05/ && .UPDATE... /Issued 738 PM CDT Thu Jun 15 2017/ A quick update to mainly trim evening low convective chances from everywhere outside of areas west of U.S. 281 from Jacksboro to Stephenville just before midnight. None of this activity is expected to be severe. Though the elevated mixed layer (EML or cap) is slightly more elevated and weaker than 24 hours ago, no surface focus is evident across our northeast counties. Any activity that does get into our far western counties just before midnight will likely be weakening quickly due to moving away from strong instability out west and encountering the aforementioned EML. Otherwise, have left pre-dawn low convective chances going for areas north of I-20, though upwind corfidi vector prognosis indicates a southeast movement of current QLCS across southeast Kansas. There is enough instability that a cold pool could develop, but this is uncertain at this time. In addition, these storms will encounter a weakening and veering low level jet just before sunrise, along with a more dry and stable environment. Main threat with any early morning storms will be lightning strikes and possibly localized gusty winds 35-45 mph with any stronger activity that maintains. Heat index values will push the bottom limits of a heat advisory criteria Friday afternoon from DFW to the Red River. However, Saturday looks to be of higher concern and more widespread, as hotter high temperatures with brief strengthening of the upper ridge combine with continued highs dew pts in the upper 60s to middle 70s. Our overnight crew will take another run on actual forecast dew points and heat index values, then make a determination for any heat advisories either for both days (Friday/Saturday) or just for Saturday. 05/ && .AVIATION... /Issued 656 PM CDT Thu Jun 15 2017/ /00z TAFs/ The benign weather pattern will persist across North Central Texas through Friday, as upper level ridging and subsidence holds sway. As has been the case for the past few days, scattered thunderstorms have again developed along the dryline over West Texas late this afternoon. The trajectory of these storms would theoretically bring them into the western sections of North Texas by 05z, and the HRRR guidance is actually advertising this. However, the cap remains pretty strong in this area and there isn`t a compelling moisture or instability feature to support the maintenance of this activity into Western N TX. Regardless, any storms that do survive will remain well W of the DFW-area or Waco TAF sites this evening, and would only affect the Bowie/Glen Rose corner posts at most. Otherwise, an area of low level stratus will again develop and drift northward to near a Lampasas-Waco-Palestine line by 12z Friday. MVFR ceilings will be persistent along and south of this line during the 10z-15z timeframe, with a brief period of BKN012 conditions expected at Waco within this window. No low clouds are expected farther N at the DFW-area sites. Typical daytime mixing will yield scattered cumulus clouds across the area after 15-16z. With a very steady state surface pattern in place, winds are expected to remain southerly at speeds of 10-15kts through Friday night. Bradshaw && .DISCUSSION... /Issued 327 PM CDT Thu Jun 15 2017/ Our attention over the next 18 hours will be focused on two main areas that may bring rain to parts of North Texas tonight and/or Friday morning. Storm development is already occurring in the Texas Panhandle and in Central Kansas, both on the north- northeast side of the upper level ridge. The storms in the Panhandle are developing along the dryline which is not expected to move much farther east. However, the mean wind flow will carry these storms to the east and southeast. Similar to yesterday evening, these storms may approach our western counties but they should be weakening and dissipating as they approach our western border. However, will keep a mention of low rain chances in our far north and northwest counties tonight. The storms in Central Kansas seem quite a bit far north to track into Texas, but we will be watching the progress of this complex. There is a considerable spread between the models on where this complex will track, but Corfidi vectors for forward propagating MCS activity support a track overnight to the south or south- southeast. In addition, an axis of higher instability is forecast to remain across Oklahoma, which the MCS should favor, and its movement will also be aided by a disturbance moving south. However, as the MCS moves south it will encounter a dry and capped atmosphere that may quickly result in a diminishing of the rain activity. But, at least part of the complex could clip our northeast counties starting early Friday morning and have kept low PoPs in that area for this reason. Have also carried low PoPs through Friday morning mainly east of the Interstate 35 corridor. For the afternoon hours, will retain a dry forecast, but any remnant mesoscale boundaries may warrant an inclusion of PoPs, most likely across the eastern half of the region. If any storms develop Friday afternoon, they could be strong with gusty winds and small hail. The remainder of the weekend should be dry and hot with temperatures reaching just above 100 degrees in our western counties. Heat index values on Saturday may warrant a Heat Advisory with values at or above 105 degrees for approximately half of the region, including Waco and the DFW Metroplex. We will continue to monitor this trend through Friday night. On Sunday, the upper level ridge will still be anchored to our west, but a front will move into the region. The timing of the front will likely be in the afternoon or evening hours, so the day time will still be hot in the 90s. The front isn`t expected to push all the way through Central Texas, but will stall and quickly retreat north on Tuesday. With the front will come a chance for rain. Best rain chances will be Sunday night with some lingering activity on Monday, in particular where the stalled boundary will be located. If the front does push farther south or if convection along the front pushes the front farther south, we could have a drier forecast on Monday. Low rain chances may linger across parts of the region much of next week depending on the upper level pattern, but discrepancies between the larger scale features lean us towards a dry forecast for now. JLDunn && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 79 97 78 98 78 / 20 20 5 0 0 Waco 77 96 77 97 77 / 5 10 5 0 0 Paris 75 94 75 94 76 / 30 20 5 0 0 Denton 75 97 77 97 77 / 20 10 5 0 0 McKinney 77 96 77 96 77 / 30 20 5 0 0 Dallas 79 97 79 98 78 / 20 20 5 0 0 Terrell 76 94 77 96 76 / 20 20 5 0 0 Corsicana 76 93 77 96 76 / 10 20 5 0 0 Temple 76 95 76 97 76 / 5 10 5 0 0 Mineral Wells 74 97 76 100 75 / 20 10 5 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 05/66
Area Forecast Discussion
National Weather Service Huntsville AL
844 PM CDT Thu Jun 15 2017 .NEAR TERM...(Tonight) Issued at 844 PM CDT Thu Jun 15 2017 A weak surface high has settled over the area this evening. The rainfall from the earlier storms will combine with light winds and mostly clear skies and result in a potential for areas of fog tonight. Locations that received the heaviest precip amounts could see dense fog developing after midnight. The one thing that may be a hindrance to fog development tonight is the amount of debris clouds we have over the area from storms to our south. Storms redeveloped over central MS and have sent some high level cirrus clouds into the area but on a whole clouds are beginning to clear out. Latest SREF, NARRE, and HRRR are pointing towards more widespread dense fog over NW AL, in TN, and in the valley locations in NE AL. The rain cooled air has brought temps and dewpoints to within a degree or two and overnight lows may only drop another degree or two. A dense fog advisory might be needed later tonight but want to wait a few more hours to watch the obs trends before sending anything out. .SHORT TERM...(Friday through Saturday) Issued at 320 PM CDT Thu Jun 15 2017 With the area in a minor shortwave ridge position at 500 mb on Friday, a weak subsidence inversion develops which may inhibit deep convective development on Friday. Since it is weak, will opt to keep a low chance in at this time. Temperatures should still warm back into the u80s to l90s. High pressure and upper level ridging remains in place over the southeast into Saturday, as multiple disturbances move into the western portion of the ridge over the area. This will continue to produce scattered shower and thunderstorm activity. Gusty winds, heavy downpours, and frequent lightning will be possible with stronger storms. Models show very warm temperatures at 925 mb developing (between 23 and 27 degrees - especially west of I-65). Since only expecting low chance pops on Saturday, it won`t take much insolation to reach the 92 to 94 degree range in hot spots. This will allow heat index readings to climb to around 102 degrees in some locations. .LONG TERM...(Saturday night through Wednesday) Issued at 320 PM CDT Thu Jun 15 2017 Expect isolated to scattered showers and storms to continue Saturday night. Rain chances do not increase much on Sunday. With similar conditions in place, expect highs again between 92 and 94 degrees. Again, heat index readings look to climb to around 100 degrees in spots. Gusty winds and frequent lightning look to be the main threats with stronger storms. A better chance of rain looks possible Sunday night into Monday, as a longwave trough axis and associated frontal boundary approach and then move through the area. Shear remains non- existent with this system and no low level helicity is forecast. Thus, only expecting some strong storms producing gusty winds, heavy downpours, and frequent rainfall. Thicker cloud cover and higher precipitation coverage should provide a bit of relief to the hot and humid conditions Monday. As drier and somewhat cooler air pushes into the region behind the departed front Monday night into Tuesday lower temperatures and more comfortable conditions are expected. Highs look to return back into the mid to upper 80s and dewpoints into the lower to mid 60s. High pressure will build back over the area on Tuesday and remain in control of the forecast through Wednesday. Isolated shower and storms return to the forecast by the end of the week as additional energy pushes into the western edge of the ridge. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 620 PM CDT Thu Jun 15 2017 Some lingering light rain and low clouds continue across portions of the area and could move briefly over the HSV terminal between 00-02z this evening. Otherwise, expect a clearing trend in cloud cover. The widespread rain this afternoon and clearing skies with light winds tonight is a good setup for fog to form. Some portions of the area could see patchy dense fog of a 1/4 mile or less. Have lowered vsbys at the terminals with models showing more confidence in potential for fog. Fog should clear by 14-15Z Friday morning leaving VFR conditions and SW winds around 5kts. A few isolated storms are possible in the afternoon. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...Stumpf SHORT TERM...KTW LONG TERM...KTW AVIATION...Stumpf For more information please visit our website at
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
900 PM CDT Thu Jun 15 2017 .UPDATE... 900 PM CDT For Evening Update... Cluster of thunderstorms have developed across northeast Iowa since late this afternoon, in association with a mid-level disturbance tracking east across the region. RAP analysis data indicates these storms have developed on the nose of weak but persistent southwesterly 15-20 kt 925-850 mb jet, along the northern edge of a 2000-3000 J/kg MUCAPE axis across southern IA/central IL. While boundary layer is beginning to stabilize with loss of diurnal heat, slightly elevated storms will likely continue to develop and spread east-southeast into the night as mid-level speed maxima propagates eastward. 40-50 kt 0-6 km bulk shear will continue to support organized convection, with some potential for a wind/hail threat especially early. However, the strongest cells northwest of the Quad Cities should tend to propagate more southeast along the edge of the stronger instability gradient. Overall severe threat, while not zero, should decrease with time and eastward extent. Warm advection ascent persists overnight, with many of the high res convection allowing models continuing to develop showers/storms behind the initial batch, lingering into early Friday morning in some spots. Overall, going forecast reflects this with likely pops overnight generally along/north of I-80 over northern IL. Tweaked hourly pops a bit out west for timing, but otherwise have maintained character of previous forecast. Ratzer && .SHORT TERM... 217 PM CDT Through Friday... Short term concerns center on thunderstorm chances and timing later this evening and early overnight hours, and some continued heat and possibly a few storms on Friday. The mid level flow is increasing across the plains on the southern extent of close upper level low across centered near the Manitoba lakes. Several disturbances in the westerly flow are evident in water vapor across the upper midwest and plains, with the speed max of interest across Nebraska/Iowa. Tonight this speed max combined with an increasing southwesterly low level jet is expected to lead an increase in convective coverage from Iowa southwest to Missouri this evening. The first half of the evening across our area appears dry, but this combined ascent atop a modestly unstable airmass (stronger to our west) combined with increasing shear should lead to at least scattered convective clusters spreading across northeast Illinois later this evening and spreading into NW Indiana after midnight. Strong to locally severe storms are possible. There is better co-location of instability and shear across north Central Illinois where the current Marginal risk for severe storms exists. Hail and damaging wind are the main hazards with 1000 J/KG of MUCAPE and 35-40 kt of effective shear available and mid level lapse rates encroaching above 7 deg/km, with the wind concern due to lingering downdraft CAPE. Confidence on storm coverage Friday is pretty low, following this more organized wave overnight. The airmass changes very little into Friday as the lower level flow remains out of the southwest. Have maintained some lower chances of precipitation given the continued train of subtle waves in the active west flow aloft. Temperatures look to still remain warm, but likely shave off a few degrees with some lingering cloud cover and slightly cooler low level airmass. KMD && .LONG TERM... 344 PM CDT Friday night through Thursday... Main forecast concerns are with continued periodic thunderstorm chances through the period, with above normal temps expected into the start of the weekend. The threat of thunderstorms will remain at the start of the period, once again, stemming from whatever develops during the day. Confidence with overall coverage is lower for Friday night, but the potential for at least scattered thunderstorms seems probable given the instability/moisture in place and with continued large scale ascent likely. Also, some threat for at least a stronger storm will also continue during this time. The period to continue to keep an eye on will be Saturday into Saturday night as guidance is advertising the potential for additional severe weather across the region. Of course, details to still fall out with successive forecasts/updates. However, a dynamic system with strong mid and upper level flow is anticipated to be in place, as a more amplified pattern swings a deepening surface low across the region. At this time, potential shear in a strongly unstable environment in this pattern would continue to suggest that all severe weather hazards are possible. Although this is possible, will continue to watch some limiting factors such as exact placement/evolution of the surface low as well as the possibility for morning convection that could complicate exactly how the day will unfold. At this time, the highest threat of severe weather looks to be later in the day Saturday into Saturday night. Once again, this is a period worth monitoring given the potential severe threat. A cooler and drier air mass expected by Sunday with the potential for thunderstorms expected to lower. This is as a large upper level trough settles overhead into early next week. Chances for precip do lower for this period but with the region remaining in cyclonic flow, scattered showers and an isolated thunderstorm can`t be ruled out. Warm and moist pattern looks to return by mid/late week next week, with an active pattern once again appearing possible. Rodriguez && .AVIATION... For the 00Z TAFs... 637 pm...Main forecast concern is thunderstorms this evening into early Friday morning. Area of thunderstorms developing over northern IA will continue moving east/southeast this evening reaching northwest IL by mid evening and the Chicago area terminals toward midnight. Confidence is high for scattered thunderstorms and timing but they should be in a slow weakening trend as they move across the terminals. Thus there could be breaks in the convection. An outflow boundary is possible ahead of these storms but confidence is low. If there is an outflow...its likely to be from the west/northwest and trends will need to be monitored as the storms approach. There appears to be at least isolated coverage showers and thunderstorms that may fester through sunrise and extended the vicinity mention for this potential but confidence is low. Trends seem to support any additional thunderstorm development Friday remaining south of the terminals during the day...with the potential for another round of thunderstorms late Friday evening into early Saturday morning. A lake breeze remains just east of mdw and appears to be generally stationary. With time...expect this boundary to move west and then dissipate after sunset. Winds will likely turn light southeasterly this evening and then settle to light southwesterly overnight with south/southwest winds increasing to 10-15kts Friday. cms && .MARINE... 344 PM CDT As low pressure over Manitoba slowly moves northeast to James Bay through Saturday, expect generally southerly flow to be in place across the entire lake with speeds likely staying confined to 10 to 20 KT. In the near term, dense fog remains in place mainly across the northern third of the lake. As it appears to remain in place for several more hours, have issued a dense fog advisory through this evening. Although some lower confidence as to when this dense fog will diminish, the more widespread dense fog should should diminish this evening. Will likely see an increase in speeds this weekend, later Saturday into Saturday night. Some potential for winds around 30 KT, however, lower confidence with this possibility. The likelihood of thunderstorms will complicate the wind field across the lake during this time. Rodriguez && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Omaha/Valley NE
328 PM CDT Thu Jun 15 2017 .SHORT TERM...(Tonight through Sunday) Issued at 327 PM CDT Thu Jun 15 2017 The chance for convection through Saturday is the primary forecast concern. Zonal mid level flow pattern will continue into Saturday before stronger shortwave swings through the Plains, bringing northwest flow aloft for the end of the weekend. Several perturbations rolling through the westerlies could trigger scattered thunderstorms across our area beginning this evening through Friday before better forcing with aforementioned stronger shortwave Saturday afternoon/night. Surface front was analyzed extending from northeast Nebraska into northwest Iowa at noon today. Front will settle south later this afternoon, helped along by weak mid level impulse noted by enhancement in western/central Nebraska on water vapor imagery. RAP analysis also shows weak ripple in 500mb height fields here as well. Low level moisture was pooled from southeast Nebraska south into Kansas where lower 70s dew points were noted. However 850mb moisture was suppressed farther south from northern Oklahoma into western Kansas. Virtually clear skies into the early afternoon has allowed temperatures to climb well into the 90s in Kansas where 850 moisture was expected to expand north with approach of mid level wave. Thus best theta-e convergence area where storms have initiated was west central/north central Kansas where MLCAPE values 3000-4000 J/kg were noted. As eastern Nebraska frontal boundary sags south, 850 moisture should expand northeast ahead of it where surface moisture is already in place. Slight cooling aloft under mid level wave will yield MLCAPE values 2500-3000 J/kg there, suggesting northeast development of convection from Kansas activity into southeast Nebraska and southwest Iowa just ahead of surface front is likely. Given buoyancy forecasts, large hail is a concern for several hours this evening before front settles south ushered along by convective outflows. Frontal boundary is forecast to wash out overnight southerly low level flow expands north through eastern Nebraska and western Iowa, bringing mid 60s to lower 70s dew points back into our area by Friday morning. Another shortwave noted by several synoptic-scale models is expected to move into eastern Nebraska during the afternoon, nudging surface trough/dryline along with it. Meanwhile, MLCAPEs are forecast to range from 2000-4000 J/kg across most of our area as convective inhibition dwindles between 18Z and 21Z. Expect convection to fire along dryline from northeast to south central Nebraska before 21Z, then progress southeast with time during the afternoon and evening. Given expected instability, could see other storms pop up ahead of this main surface feature where lingering outflows/boundaries remain/set up. In any case, all storms will have potential for large hail and damaging winds with high CAPE and bulk shear near 40kt. Also see SPC`s Day 2 outlook as the early afternoon update upgraded part of southwest Iowa and east central Nebraska to an Enhanced Risk for severe. By Saturday, severe risk is more conditional on where surface moisture/fronts will lie after Friday night convection. Stronger upper trough is scheduled into the Northern Plains by mid day Saturday, and most model output shows westerly surface wind component across all of eastern Nebraska and southwest Iowa by 18Z. Thus moisture/instability profiles conducive for convection and severe will be east and south of our area during time of max heating. However, timing of these features is questionable at this point, and a slower advancement would place southwest Iowa and southeast Nebraska under threat for severe for a few hours in the afternoon. Otherwise we are looking at post-frontal showers and a few thunderstorms rolling in from the west as right entrance region of mid level jet enhances isentropic upglide from southwest Nebraska late afternoon into the southern half of eastern Nebraska and into southwest Iowa late Saturday evening and overnight. By Sunday, precipitation chance should be minimal as northwest flow through the atmosphere ushers in cooler and drier air. Highs Sunday look to tip to the cooler side of normal for a changes, with temps from the mid 70s north to the lower 80s south. .LONG TERM...(Sunday night through Thursday) Issued at 327 PM CDT Thu Jun 15 2017 While the week will start off dry and cool under northwest flow aloft, a gradual return to warmer temperatures, a little more humidity, and sporadic thunderstorm chances as flow becomes more zonal by mid week. Highs Monday in the lower 80s will gain several categories Tuesday through Thursday, reaching the upper 80s to middle 90s those days. Precipitation chances should increase Tuesday night as a first in a series of mid level shortwaves rolls into the region. Timing of each round of potential convection will be impossible to pin down this far out, but there is at least some chance right on through Thursday. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 1221 PM CDT Thu Jun 15 2017 VFR conditions are expected through the TAF period at all 3 sites. Scattered thunderstorms are forecast to develop across portions of far southeast Nebraska this evening but should remain out of the TAF sites. Did add a broken mid-level deck at KLNK to account for this. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Dergan LONG TERM...Dergan AVIATION...Kern
Area Forecast Discussion
National Weather Service Pueblo CO
304 PM MDT Thu Jun 15 2017 .SHORT TERM...(This evening through Friday) Issued at 303 PM MDT Thu Jun 15 2017 Overall, dry wly flow across CO today with temps climbing a few degf most areas versus yesterday. Back edge of unstable air mass and diffuse boundary from convection in KS lies near the CO border at mid-afternoon, with vis satellite loop showing some cumulus development into Kiowa county as of 21z. HRRR forecasts boundary and instability to drift into KS through early evening, and will keep tsra out of the forecast for all areas, though convective developments in KS could send some fairly healthy outflow westward across the plains this evening. Flow then gradually becomes more nwly overnight and through the day Friday as ridge builds over the desert SW, with max temps climbing 2-5 degf most locations as heights begin to increase. Could see some near 100f readings return to areas along the lower Ark Valley, with 90s elsewhere on the plains, 80s interior valleys and mainly 70s/80s in the mountains below 10k feet. .LONG TERM...(Friday night through Thursday) Issued at 303 PM MDT Thu Jun 15 2017 Friday night-Sunday night...Weak to moderate northwest flow aloft progged across the state with an embedded short wave translating across the Northern Tier and into the Upper Midwest. Passing wave sends a front across Eastern Colorado Saturday afternoon and evening, with moisture pooling along and behind the front helping to produce a few showers and thunderstorms late Saturday afternoon across the Pikes Peak region, with the potential for storms spreading south and west across the eastern mountains and plains through the evening hours. Timing of the front does not look to bring relief in the hot temperatures on Saturday, with highs expected to be in 90s to around the century mark across the plains, 70s and 80s across the higher terrain and in the 50s to 60s at the peaks. Sunday continues to look cooler, especially across the eastern plains, with increased low level moisture within breezy low level upslope flow into the afternoon. Some differences in how far west available works back, though cant rule out a few afternoon and evening storms across the southern mts and adjacent plains on Sunday, with temperatures mainly in the 70s and 80s across the area, with 50s at the peaks. Monday-Thursday...Upper ridging rebuilds back across the Desert SW and into the Great Basin, keeping generally week west to northwest flow aloft across the state. This will allow for temperatures to warm to above seasonal levels once again, and keep at least a chance of a few afternoon and evening storms in the forecast through the period. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 303 PM MDT Thu Jun 15 2017 VFR conditions expected tonight and Friday at all taf sites, with typical diurnal wind cycle. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PETERSEN LONG TERM...MW AVIATION...PETERSEN
Area Forecast Discussion
National Weather Service San Angelo TX
722 PM CDT Thu Jun 15 2017 .UPDATE... Increased shower and thunderstorm chances to likely for complex of storms moving southeast into the Country. HRRR has the storms complex continuing move southeast into the Big Country and northern Concho Valley...and as far east as Brown and San Saba Counties. Some could be severe...with large hail and damaging winds the main threats. 04 && .PREV DISCUSSION... /issued 629 PM CDT Thu Jun 15 2017/ AVIATION... /00Z TAFS/ VFR conditions continue across West Central Texas early this evening, but complex of storms across the South Plains should move southeast and approach the area later this evening. Latest hi-res models suggest that KABI (Abilene) will be the most likely one to see any of these storms and will continue the VCTS for now. May need to update once storm trajectory becomes more certain. Otherwise, will leave storms out for now. MVFR cigs will return by morning and will largely us the timing from this morning as a start and stop point on the low clouds. PREV DISCUSSION... /issued 332 PM CDT Thu Jun 15 2017/ SHORT TERM... (Tonight and Friday) As of mid afternoon, widely scattered thunderstorms have developed across the dryline in Lubbok`s CWA as indicated by many of the short range models this morning. These storms are expected to continue to develop towards the southeast and be located near the Big Country by early evening. Additional storms may develop near Midland later this afternoon in a manner similar to yesterday and could reach the western border of our CWA later this evening. MLCAPE values near 3700-4200 j/kg coupled with 30-40 kts of 0-6 km shear will allow for the possibility of some of these storms to become severe. If the stronger cells hold together and move into our CWA, the primary hazards will be large hail and damaging winds. The storms will likely dissipate by midnight, leaving the best rain chances along the western border of the CWA and the Big Country. For tomorrow, rain chances will have diminished overnight. The heat will once again return to West Central Texas bringing high temperatures into the upper 90s to 104. Low temperatures tonight are expected to drop into the low to mid 70s. LONG TERM... (Friday night through Thursday) An upper level ridge will centered across northern Mexico or the Southwest U.S. through the extended forecast, with its influence extending into the western half of Texas. Well above normal temperatures are forecast both Saturday and Sunday. High temperatures on Saturday will mainly be in the 100 to 105 range. A heat advisory may eventually be needed, as several locations may reach or exceed 103 degrees. An upper level trough will swing across the Plains Sunday, sending a cold front into the Big Country Sunday afternoon. High temperatures on Sunday will be dependent on the eventual strength and speed of this cold front. Ahead of the front, compressional heating will result in triple digit temperatures, while temperatures in the 80s will be possible behind the front. For now, only minor changes were made to temperatures, but these temperatures may need to be trended down, especially across the northern half of the forecast area. Slightly cooler temperature are forecast on Monday behind the front, with highs mainly in low to mid 90s. Upper level ridging will build back into West Central Texas for the middle to latter part of the work week. This will result in mainly dry conditions and temperatures above seasonal normals. && .PRELIMINARY POINT TEMPS/POPS... Abilene 75 101 76 102 / 60 10 0 5 San Angelo 75 102 75 104 / 20 10 0 5 Junction 73 98 73 100 / 0 5 0 0 Brownwood 74 98 73 100 / 30 10 0 0 Sweetwater 74 101 75 102 / 70 10 0 5 Ozona 73 99 74 101 / 20 10 5 5 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ 99/04
Area Forecast Discussion
National Weather Service Tallahassee FL
901 PM EDT Thu Jun 15 2017 .NEAR TERM [Through Tonight]... The 7 pm regional mesosanalysis showed a well-defined outflow boundary extending across central GA into southeast AL. The latest HRRR runs appeared to handle this feature reasonably well, though they were a little slow. Judging from this evening`s Tallahassee RAOB, CAPE values will only be in the 500-1000 J/kg range (depending on what level a parcel is lifted), and these parcels will need to overcome about 50 J/kg CIN from a warm layer at 800 mb. The HRRR obviously thinks the approaching cold pool can overcome this CIN, though based on recent weakening trends in the radar imagery, we suspect the HRRR is a little overdone. Nevertheless, we have increased PoPs significantly across our region for this evening, from 100% in southeast AL & southwest GA, to likely around Tallahassee, Panama City, and Valdosta, to 50% around Perry and Cross City. Given the marginal thermodynamics and poor deep-layer shear, we expect mainly showers and a few thunderstorms, and do not expect wind gusts to exceed 35 MPH. && .PREV DISCUSSION [821 PM EDT]... .SHORT TERM [Friday Through Saturday Night]... Summertime pattern will continue across the area through Saturday with weak upper trough in place. Deep-layer moisture will remain plentiful on Friday, which will support relatively high rain chances once again. By Saturday, guidance suggests some mid/upper dry air will move in from the southeast. This will likely limit coverage compared to the past several days. Near normal temperatures are expected with highs in the upper 80s and lows in the lower 70s. .LONG TERM [Sunday Through Thursday]... Significant disagreement exists for the extended period forecast, generally centered around the area of disturbed weather over the NW Caribbean Sea. The 12Z UKMET/ECMWF both develop a weak area of low pressure near the Yucatan peninsula and track it slowly west northwestward into the southern Gulf of Mexico. This evolution would have little impact on the local area, with the typical summertime convective pattern prevailing. The GFS develops an elongated trough which rotates into the northeastern Gulf by late Monday into Tuesday. While the trough is not very deep, the strength of the Bermuda high to the west would create a rather tight gradient along the west coast of Florida into the Big Bend. Along with copious amounts of tropical moisture, this could lead to breeze conditions and the potential for widespread heavy rain. Analysis of the GFS precip/vorticity fields suggests that this solution might be impacted by convective feedback issues within the model, leading to over development of the surface trough. The non-GFS solution appears to be more realistic at this point, so have hedged in that direction for the extended period with lower winds and PoPs. .AVIATION [Through 00Z Saturday]... Thunderstorms along an outflow boundary will impact DHN and ABY early in the forecast period and could make it as far as ECP, but uncertainty is too great to include at TLH and VLD at this time. These storms should be weakening with time, but could still cause a brief period of IFR or MFR ceilings and visibilities and gusty winds. A period of IFR ceilings is expected to develop during the pre-dawn hours at DHN, ABY and TLH and lift around 14Z. Another round of scattered afternoon convection is expected Friday afternoon. .MARINE... Winds and seas will generally be low through the weekend, except near scattered showers and thunderstorms. Winds and seas may begin to increase early next week as a tropical wave moves into the southern Gulf of Mexico. .FIRE WEATHER... No concerns. .HYDROLOGY... Scattered afternoon showers and thunderstorms are expected for the next several days. Rainfall accumulations will generally be around 1- 2 inches through Sunday, but isolated areas could receive that in a single afternoon. Due to the scattered nature of the storms, widespread river flooding is not expected, however, isolated flooding will be possible. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 72 88 70 88 69 / 60 60 30 40 20 Panama City 74 84 75 84 76 / 70 30 30 30 20 Dothan 71 88 72 88 72 / 100 50 40 30 30 Albany 72 89 72 89 73 / 80 50 50 40 30 Valdosta 72 88 71 88 71 / 60 60 30 50 30 Cross City 73 87 72 87 71 / 50 40 20 30 20 Apalachicola 75 84 74 84 74 / 50 30 30 30 20 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...Fournier SHORT TERM...Camp LONG TERM...Camp AVIATION...Wool MARINE...Camp FIRE WEATHER...Fournier HYDROLOGY...Camp