Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/30/18


Area Forecast Discussion
National Weather Service Binghamton NY
902 PM EDT Wed Aug 29 2018 .SYNOPSIS... A passing cold front tonight, will bring cooler temperatures and lower humidity, for the end of the week and the start of the weekend. Showers and thunderstorms tonight, associated with the frontal zone, will generally diminish in coverage Thursday and Friday, as high pressure builds down from eastern Canada. && .NEAR TERM /THROUGH THURSDAY/... 9 pm update... Just minor updates. Temperatures dropped around 10 degrees with the rain. Where they have rain temperatures won`t change much rest of the night. Across the southeast temperatures have fallen enough so that heat indices have fallen out of the 90s. Let the heat advisory expire on time. Tomorrow will be cooler and well below criteria. Thunderstorms from Madison to Steuben Counties will continue pushing east. Models have it weakening in the next few hours but not much sign of that yet. Biggest threat now will be rainfall as multiple thunderstorms go over the same areas. 130 pm update... As expected, showers and thunderstorms are forming over western/northern NY early this afternoon, tied to lake convergence boundaries and an incoming surface trough. Convection allowing models remain consistent in bringing showers/storms across our CNY zones through early evening, with a general diminishing trend in coverage/intensity towards/after midnight. ML CAPE and DCAPE of both 1000-1500 j/kg this afternoon, along with effective shear of 30-35 kt across our northern zones, suggest potential strong wind gusts. The main limiting factors remain warm mid-level temperatures/poor lapse rates, as the best short-wave support/height falls shift across Ontario and Quebec. HRRR depictions also bring some locally heavy rain across parts of CNY from about 23-02z this evening. We`ll continue to monitor, and have strong gusty wind and heavy downpour potential mentioned in our gridded forecasts. Since the actual cold front is not expected to come through until the pre-dawn period, it will be another muggy night, with lows only in the mid 60s-lower 70s. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... 140 pm update... Overall, a quieter period is foreseen. Above mentioned cold front will settle into the mid-Atlantic region by later Thursday, before slowly returning northward and washing out Friday. Any lingering showers/thunderstorms should be relegated to our NEPA zones and Sullivan County NY, lessening as the day wears on. It will also be cooler and noticeably less humid, with highs in the 70s-lower 80s. Thursday night looks mainly dry, under partly-mostly cloudy skies, with lows by daybreak in the 50s-lower 60s. Friday-Friday night, as surface high pressure shifts towards the New England coast, a low-level southeast flow will set up, transporting some moisture back towards CNY/NEPA. Since our region will reside near the southern edge of the westerlies with likely short-wave passages from time to time, we`ve introduced widely separated showers/thunderstorms back into the forecast. Temperatures will not be oppressive, with highs Friday in the 70s, and lows Friday night in the 60s. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... 240 pm update... Large dome of high pressure will build over the central eastern seaboard this weekend and early next week. The nrn edge of the ridge will set up somewhere across the sern Great Lakes into New England. A series of short waves will ride ewd along the periphery of the ridge during this time and interact with an increasingly unstable air mass to produce showers and thunderstorms. The most favorable area for convection will likely be across the nrn tier of counties, but cannot be ruled out anywhere at this point. The most favorable time for precipitation is expected to be during the afternoon and evening hours pretty much every day Saturday through Tuesday...during peak heating when the boundary layer is most unstable. && .AVIATION /01Z THURSDAY THROUGH MONDAY/... VFR conditions persist this evening with scattered showers and isolated thunderstorms dropping conditions to IFR for brief periods of time. Should continue to see the convection diminish in intensity after the cold front passes later this evening. Will likely see low clouds and fog with MVFR/Alternate Required conditions developing after 06Z in the NYS terminals. Fog and clouds lift after 14Z...with VFR conditions through 00Z Friday. Light west winds around 5 kt or less tonight...becoming nw around 5 to 10 kt Thursday afternoon. Outlook... Thursday night through Friday...Main VFR. Friday night through Monday...Mainly VFR. May see restrictions in showers and storms. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...MLJ/TAC NEAR TERM...MLJ/TAC SHORT TERM...MLJ LONG TERM...BJT AVIATION...BJT/RRM
Area Forecast Discussion
National Weather Service Caribou ME
911 PM EDT Wed Aug 29 2018 .SYNOPSIS... Low pressure from Quebec will cross the northern Maine this evening. A trailing cold front will move southward towards the coast late tonight into Thursday morning. Cooler and drier air will move into the area later Thursday and Friday as Canadian high pressure builds southward. && .NEAR TERM /THROUGH THURSDAY/... 9:12 pm update: In collaboration with SPC and WFO Gray we dropped the severe thunderstorm watch around 8:30 pm this evening. There are still a few thunderstorms in the FA, mainly in the Bangor Region and in southeast Aroostook County. A cold front is now pushing into the Saint John Valley with a narrow line of showers, and the front will sweep down to the Downeast Coast by morning. Removed any severe weather mention, but did maintain heavy rain wording for the next few hours. Noted that the KCAR sounding precipitable water was 1.98" this evening and we had a report of 1.4" of rain at Crystal in just 12 minutes earlier this evening. The main update at this time was to the PoPs to account for what is currently being observed on radar along with the expected trends the remainder of the night. Previous discussion: SPC has issued a Severe Thunderstorm Watch for Northern Somerset, Piscataquis and Penobscot County until 11 PM. Radar showed activity apchg the western ME border running into the region where the latest RAP showed MUCAPE of 1500+ joules w/0-6km bulk shear of 50 kts. Meso analysis continues to point to the best area of Severe potential to be across the Piscataquis and Mount Katahdin region into the Penobscot region. This is not without saying that portions of north Maine such as Clayton Lake into Shin Pond. The RAP and the latest LAP soundings showed potential for cells to have Supercell structure w/good rotation. Some storms could deviate to the right showing potential for tornadic potential. Sfc warm front was lifting nne as dewpoints were climbing. Heat index values reached 90-95 across portions of interior Downeast thanks to more heating and dewpoints around 70. As clouds move in later, readings will drop off. One other note to make is that PWs are nearing 2" and w/cells possibly aligning w/wsw flow aloft leading to training w/heavy rain. This will need to be assessed. Cold front is slated to push across the region later in the evening as sfc low rides across northern ME. There appears to be a decent amount of rain w/0.25 to 0.50 inches. across portions of western and northern areas. Cooler and drier air to follow behind the front overnight into early Thursday morning. The downeast region will be the last to see this drier and cooler air. Thursday will definitely have a much different feel to the day w/breezy conditions and much cooler temps. Might see some stratocumulus development through the day but any shower activity will be in the morning. Daytime temps will run into the upper 60s to lower 70s north and west w/central and Downeast areas in the 70s. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... High pressure builds through the period. On Friday night, lows will dip to the upper 30s to lower 40s in the Allagash with a steep radiation inversion, but remain in the mid to upper 50s for Bangor and the coast as winds are expected to prevent as steep of an inversion. With the high to the north, H925 to H850 moisture moving eastward is always a concern. At this time, will add some clouds along the coast Friday morning, but clear it out by afternoon. Highs will be mostly in the lower 70s. On Friday night, all areas should radiate well with widespread lows in the 40s. The high continues to strengthen in the Canadian Maritimes into Saturday. H850 temps look slightly warmer on Saturday...supporting surface highs creeping back to the low to mid 70s. Overall H850 moisture looks more widespread on Saturday and will go with partly sunny for most of the area. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Forecast for the latter half of the weekend and into next week remains similar to previous shift`s thoughts. High pressure remains parked off the coast of North Carolina with anticyclonic flow aloft guiding shortwave disturbances around it. These will intermittently train across Maine. Lingering showers Saturday night cross central ME and Downeast. Another shortwave boundary approaches Sunday, crossing Monday/Monday night with GFS and ECMWF most aggressive, while the GEM is weaker in precipitation coverage. Kept PoPs slight to low chance. High pressure slides north of the region Wednesday, with continued slight chances of showers. && .AVIATION /01Z THURSDAY THROUGH MONDAY/... NEAR TERM: Generally VFR at the Downeast terminals tonight and Thursday with briefly lower conditions possible in any showers and thunderstorms. Conditions will lower to IFR to MVFR at the northern terminals late this evening and overnight, but will improve to high end MVFR to VFR Thursday morning. SHORT TERM: VFR into Sunday w/a brief period of MVFR by Sunday morning mainly for KBGR and KBHB. && .MARINE... NEAR TERM: No headlines w/winds 5 to 10 kts tonight picking up to 10-15 kts and veering to the nnw as the front drops across the waters Thursday morning. Seas will stay around 2-3 ft. SHORT TERM: No headlines expected for this term. Winds will drop off by Friday to 5 to 10 kt as high pres moves in and look like they will hold that way into Sunday. Seas will remain 2-3 ft. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...CB/Hewitt Short Term...MCW Long Term...Cornwell Aviation...CB/Hewitt/MCW Marine...CB/Hewitt/MCW
Area Forecast Discussion
National Weather Service State College PA
1133 PM EDT Wed Aug 29 2018 .SYNOPSIS... A cold front over the Great Lakes will push southeast into Pennsylvania tonight and move very slowly to the south on Thursday. The front will stall out just south of the region Friday and Saturday, then return north as a warm front late in the weekend. A building subtropical ridge is expected over the Mid Atlantic region early next week. && .NEAR TERM /UNTIL 8 AM THURSDAY MORNING/... Winds along the lakeshore are srly now with real wind shift now somewhere over the lake. Big line of showers is breaking up as they weaken considerably. Any clearing will likely be brief in the NW, with lower clouds across the ponds and higher clouds streaming in from the southwest. Really low clouds in GKJ and JHW. The lone cell in srn Franklin Co has moved thru Adams Co and has started to break up, but is still going into York, now. All is well in the general scheme of the forecast. Only some tweaks to very near- term POPs and Wx. Prev... Quick hitter of strong to severe storms this evening. Loss of heating is weakening things as the storms also drop into much lower shear. HRRR, HREF, RAP all break this stuff up quickly, generally before 10 PM. All guidance also indicates a very low chc of a shower through the night over the NW/mtns. After some brief clearing behind this line of showers/storms, clouds will move into the NW, and may not leave for quite a while. It will be muggy overnight as wind will be light, even for those areas that manage to clear. Dewpoints stay in the upper 60s and lower 70s over most of the area. Perhaps only the NW will get below 65F dewpoint, but they`ll have the clouds. Prev... Another very warm and uncomfortably humid late summer afternoon across central PA. Convection has been inhibited by warm temps aloft and a ribbon of relatively lower pwats over the Alleghenies keeping the day rain-free for most. Saw a lone shower cell fire over the Lower Susq at mid afternoon before collapsing within 30-45 minutes. The best chance of showers/storms will come this evening across the northwest counties as slowly approaching cold front and prefrontal lake breeze boundary push into my northwest counties. Sufficient mid level flow and shear noted ahead of this feature may still support an isolated stronger storm this evening over the northwest. In addition, a few rogue cells may reach into the Laurel Highlands but these are increasingly encountering warmer mid levels and will likely dissipate before reaching my area. Heat Advisory remains in effect for our Susq Valley and Scent Zones through this evening. After the evening diurnal maximum, expect a broken line or two of showers with isold tsra to be tracking through the northwest and central mountains late tonight into the pre dawn hours Thursday as the front slowly advances. Aside from an isolated evening shower or storm, the east and south should remain dry overnight. && .SHORT TERM /8 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... Secondary surge of cooler air will push the stalling sfc front into my southeastern counties on Thursday morning through midday. Although the large scale forcing is less than impressive, diurnal heating of moist/unstable air mass is likely to support scattered convection across the southern counties during the late morning and afternoon. Shear is meager, so limited threat of organized severe weather at this time. The most pronounced cooling Thursday will be across the northwest mountains, where model soundings suggest the day will begin with upsloping stratus/patchy drizzle. Brightening skies are expected by afternoon, but model blends only indicating highs in the low 70s. Meanwhile, warm and humid conditions are likely to persist ahead of secondary cold front with highs in the mid to upper 80s over the Lower Susq Valley. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... The medium range guidance has the high continuing to be pushed off shore as a shallow trough moves through and should bring break from the heat Friday and Saturday. High pressure tracking across New England will push frontal boundary south of the region and result in a cooler southeast flow off the Atlantic. Model soundings indicate there will be a fair amount of cloud cover both days, along with the chance of showers, primarily in the region of best orographic forcing over the south central mountains/Laurels. Both the 12Z NAEFS and ECENS indicate a return to very warm and humid conditions Sunday through Tuesday, as surface high drifts southeast off the east coast, allowing the stalled frontal boundary to lift north as a warm front. A subtropical ridge over the western Atlantic is progged to retrograde, taking up residence over the Mid Atlantic coast by early next week. Under the influence of this feature, expect above normal temperatures, high humidity and a daily chance of PM convection. && .AVIATION /04Z THURSDAY THROUGH MONDAY/... Late evening update, minor adjustments for weakening line of showers and storms. Earlier discussion below. Weakening line of showers and storms to the west. Did push thunder into JST, AOO, UNV, and IPT for 00Z TAF package. Left out of MDT and LNS. Main issue late tonight into Thursday morning will be low clouds and fog. Expect conditions to improve by late morning or early afternoon on Thursday. Slightly cooler and less humid across the north. Thus only have showers in for the southeast, where front is likely to stall. .Outlook... Fri...AM restrictions (as low as IFR or LIFR) in fog/stratus, then VFR. Sat...MVFR cigs with chc -shra and areas of drizzle. Sun...Chance of showers and storms. Mon...Still a chance of showers and storms. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...DeVoir NEAR TERM...Dangelo/DeVoir SHORT TERM...DeVoir LONG TERM...Fitzgerald/Ceru AVIATION...Martin
Area Forecast Discussion
National Weather Service Hastings NE
809 PM CDT Wed Aug 29 2018 ...Short Term Update... .UPDATE... Issued at 801 PM CDT Wed Aug 29 2018 Sent a forecast update to remove the drizzle from the forecast for tomorrow morning. Still expecting fog and stratus to move into the area, but forecast soundings from the RAP and HRRR make me doubtful that near-surface moisture will become deep enough for drizzle before increasing winds begin to mix out the boundary layer. Also made minor tweaks to shower/thunderstorm chances tonight and tomorrow morning. HRRR and NAMnest keep activity southeast of the area, so I`ve restricted PoPs to only our Kansas counties for a short window from 5-9am. && .SHORT TERM...(This evening through Thursday) Issued at 241 PM CDT Wed Aug 29 2018 Today has been the transition day between the post frontal/cooler conditions Monday and the return of more humid and warmer air for the latter part of the workweek. The pattern aloft featured fairly zonal flow across the CONUS, while at the surface, high pressure was centered in east central Nebraska. As we head into tonight, the surface ridge axis will migrate eastward, allowing for return flow of southerly winds. This will draw moisture northward with dewpoints climbing back into the 60s Thursday. Low cloud cover is expected to develop and spread north overnight and hold firm through at least the morning on Thursday, with some gradually clearing southwest to northeast. This being said, some models hold onto clouds in our far northeast through the day and some areas may not see much sun before dark. Have added patchy fog/drizzle to the forecast late tonight into Thursday morning with the increasing low level moisture and lift. Precip chances are not overly high and definitely not widespread, however shower and isolated storm development is not out of the question on the nose of the low level jet in our southeast zones late tonight, with small chances for a hit or miss shower/storm carrying into Thursday in the warm air advection regime. Cloud cover could impact high temperatures Thursday and have lowered readings in our eastern areas where clouds will be slower to depart. As stated above it could be a late day warmup given timing of cloud departure, with 70s expected in our east and 80s in the south/west. .LONG TERM...(Thursday night through Wednesday) Issued at 241 PM CDT Wed Aug 29 2018 Precip chances shift east Thursday night as the axis of the low level jet orients towards the Missouri River. Friday is still shaping up to be the warmest of the week with highs near or in the 90s ahead of an approaching cold front, while the pattern aloft transitions southwest ahead of an upstream trough. Friday will also be noticeably humid with dewpoints in the upper 60s/near 70F combining with the warm temps to produce head indices in the mid/upper 90s in the afternoon/early evening. The surface trough and cold front remain to our west through the day Friday, then chances for storms return Friday night as the cold front arrives. This frontal boundary will be the focus for showers/storms into the Labor Day holiday weekend with the better chances for convection expected in the late day/overnight hours aided by a strong low level jet. Look for temps to cool back to more seasonal readings by Saturday behind the front with readings forecast in the low/mid 80s through Monday. Next week the pattern continues to favor west/southwest flow aloft with intermittent chances for storms continuing due to disturbances in the flow and boundaries in the area. The pattern looks to change around the middle of the week, trending cooler and wetter with a arrival of a stronger cold front associated with a Canadian upper trough. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday) Issued at 619 PM CDT Wed Aug 29 2018 Expect stratus to move into the area around dawn on Thursday. IFR ceilings are likely. Short-term models are also indicating a threat for fog, mist, or possibly light drizzle for a brief period on the leading edge of the stratus. This reduced visibility should be relatively brief, and will end as winds pick up by mid morning. Low clouds will continue to be the main impact into the afternoon, with ceilings only slowly rising and scattering out by Thursday evening. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ UPDATE...Mangels SHORT TERM...Fay LONG TERM...Fay AVIATION...Mangels
Area Forecast Discussion
National Weather Service Goodland KS
623 PM MDT Wed Aug 29 2018 .UPDATE... Issued at 610 PM MDT Wed Aug 29 2018 Latest high resolution guidance is showing a significant increase low level moisture across the area after midnight. This will lead to fog developing and spreading across much of the area. The fog will continue through the morning hours on Thursday. The great coverage of fog and best chance of dense fog will be along and west of the Colorado border. In addition to the fog am expecting skies to become mostly cloudy to cloudy. && .SHORT TERM...(Through Thursday night) Issued at 330 PM MDT Wed Aug 29 2018 Overview: The Tri-State area will remain at the southern fringe of the westerlies -- on the northern periphery of an upper level ridge over TX and the Desert SW. Today: Isolated convection has developed in far western NE (north of Kimball) this afternoon, presumably in association with low- level upslope flow and weak DPVA attendant a small amplitude wave at 300 mb (per 20Z SPC mesoanalysis). Expect the aforementioned convection to remain isolated and eventually weaken/dissipate as activity progresses east into an increasingly hostile thermodynamic environment. Tonight: Airmass modification will begin in earnest tonight as high pressure shifts northeast from Iowa to the Great Lakes and southerly return flow strengthens over the High Plains. Strengthening warm advection will aid in moderate nocturnal destabilization overnight as increasingly rich low-level moisture advects beneath a pristine EML (H7-H5 lapse rates 8-9 C/km). HRRR and NAM NEST simulated reflectivity forecasts suggest that elevated convection may develop east of Highway 83 between 09-12Z Thu morning -- coincident with the strongest low-level warm advection in northwest KS -- though the best forcing (and best overall potential for convection) should be along/east of Highway 283. Thu-Thu night: Any elevated convection that develops Thu morning should shift E/NE away from the Tri-State area during the day -- in concert with the strongest low-level warm advection. Expect dry conditions to prevail otherwise, with noticeably warmer highs in the upper 80s (east/northeast) to lower 90s (west/southwest) and lows ranging from the upper 50s to upper 60s, warmest in the east. .LONG TERM...(Thursday night through Wednesday) Issued at 129 PM MDT Wed Aug 29 2018 The forecast period begins with a weak synoptic pattern. The jet stream is largely confined to Canada with a weak jet finger entering the CONUS through central California and flowing over the forecast area before terminating in Iowa. Two large high height circulations are noted, one off the New England coast and another over Texas. This is creating a large area of confluence over the Central CONUS. Subsequently, an area of upper-level divergence exists over the border SD/NE over where a low pressure circulation has formed. Frontogenesis has occurred off the low circulation and as of Friday morning, a relatively weak cold front approaches the area from the north. With the Gulf of Mexico being open, southerly flow has created a notable dew point gradient over Kansas and Nebraska. The front will tap into the available moisture and set off showers and thunderstorms Friday evening and every subsequent evening thereafter as it becomes stationary and hovers over the forecast area before receding north by Monday evening. It is noteworthy that the theta-e gradient also recedes along with the frontal boundary and continues to recede westward throughout the forecast period. Friday: Precipitation begins in the evening with chances hovering around 20% with higher PoPs NE of the forecast area. Showers and storms are more likely and will be stronger in the northeastern counties. SBCape gradient increases in intensity up to 3800 j/kg according to the GFS and over 4800 j/kg according the NAM in the NE trajectory as well as the 0-6km bulk shear which is projected at up to 45 kt. GFS soundings indicate DCape over 1400 j/kg and NAM soundings estimate it at almost 1800 j/kg. Precipitable water is also high with both models agreeing at just under 1". At this time low confidence remains in forecasting any severe cells, however, based on the aforementioned information, this should be further investigated with subsequent model runs to see if severe criteria still exists. Saturday: Most of the day will be wet with storms tapering off due to diurnal cooling and reigniting with diurnal heating as the boundary is now forecasted to become stationary and mid-level disturbances move over the area. SBCape values and PW values increase for Saturday`s convection. Sunday-Wednesday: The pattern will remain very similar with subtle differences in timing of the onset of precip which intensifies in the afternoon and evening hours. Showers/TStorms will likely diurnally driven until further notice. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 610 PM MDT Wed Aug 29 2018 For Kgld, south winds of 8 to 13 knots will continue through Thursday morning. Around 09z and continuing until 16z mvfr conditions are expected due to fog and low ceilings. After 16z vfr conditions will return. At 18z, the southwest winds near 7 knots will continue until 21z when they shift to the southeast at 8 knots. For Kmck, vfr conditions and southeast winds near 9 knots are expected through 12z. At 12z the winds will shift slightly to the south as mvfr ceilings will develop at the site. The mvfr with occasional ifr conditions are expected into early afternoon. At 20z, south winds near 7 knots and vfr conditions are expected and will continue through the end of the period. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...VINCENT LONG TERM...SANDERSON AVIATION...BULLER
Area Forecast Discussion
National Weather Service Jackson MS
943 PM CDT Wed Aug 29 2018 .UPDATE... Updated for evening discussion. && .DISCUSSION... Latest regional radar/satellite showing showers/thunderstorms across much of the northeastern half of the CWA. Convection should start to die down over time as the boundary layer stabilizes. Dew points are forecast to hover around 70, which will make for a muggy overnight. After midnight, included some patchy fog in the Hattiesburg area which should fill in a bit more with the moisture-rich soil from recent rainfall. We may have to watch that area for possible dense fog, as well. For tomorrow, high pressure centered just off the North Carolina coast will dominate the weather, with temps again getting into the upper 80s to low 90s. HRRR does depict some showers or storms as early as 12z from an old MCV or disturbance, so added some slight showers in the northeastern third of the CWA. /TWP/TW/ Prior discussion below: Current afternoon storm activity is working out mostly as expected, the exception being the better coverage across the NW areas. Look for activity to slowly evolve through 5pm with a downward trend between 6-8pm. There remains some potential for strong storms and possibly a few reaching severe limits. Updrafts have been a bit more robust than yesterday, but they are still falling short. The evening will be quiet with persistence being the rule for low temps. For Thu, model consensus has trended to lesser in the way of PoPs and I have followed that suggestion. There will still be activity and no area can be ruled out, but better chances look to be across the N/NE/E parts of the forecast area. Like today, some strong storms will be possible with gusty winds being the main threat. Temps aloft will again be on the cooler side, but not as cool as today which supports the expectation of strong storms. As for temps, like with lows, a persistence approach is best and highs will mainly range from 90-93. /CME/ Thursday night through next Tuesday: Warm and humid conditions will continue across the area through the period, as high pressure off the east coast will result in east to southeast flow. High temperatures will range from the upper 80s to mid 90s, with overnight lows mainly in the 70s. The humidity should remain low enough to keep heat index values below 105 degrees. As for precipitation, decent chances for afternoon and evening showers and thunderstorms will persist through the period. This activity looks to dissipate during the evening hours, with quiet weather expected during the overnight hours. /27/ && .AVIATION... 00Z TAF discussion: Showers and storms continue to occur around the region, with some potential for affecting TAF sites. Any site that sees SHRA/TSRA can expect brief vis and ceiling restrictions. A return to VFR conditions should occur following storms, all of which should diminish through the evening and lead to a quiet overnight. There is some low end potential for some MVFR conditions at PIB/HBG/JAN/HKS between 11-15z, with a return to VFR conditions at all sites after that. /28/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 71 91 71 92 / 20 25 19 41 Meridian 71 89 71 92 / 19 34 27 43 Vicksburg 71 93 72 93 / 20 20 20 34 Hattiesburg 71 88 71 90 / 20 49 27 51 Natchez 71 90 72 92 / 20 25 21 38 Greenville 73 89 72 90 / 21 25 14 37 Greenwood 73 90 72 92 / 58 28 16 39 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ TW/27/28/CME
Area Forecast Discussion
National Weather Service Jacksonville FL
930 PM EDT Wed Aug 29 2018 .UPDATE...Showers and storms have decreased in coverage and intensity across inland areas due to loss of daytime heating. However...scattered showers and isolated storms continue across the coastal waters and portions of Ne Fl due to a moist and unstable Se flow. This activity will move northwest affecting coastal areas the next several hours. Brief periods of heavy rain and gusty winds possible. High- res HRRR indicating a re-surgence of scattered showers/isolated storms along the Ne Fl coast during the pre-dawn hours on Thu. && .AVIATION...Scattered showers continue to move northwest across the area and have VCSH at all terminals til 06Z. Patchy late night fog possible and continued previous fcst of ocnl MVFR vsby at GNV and VQQ between 09Z-11Z. && .MARINE...Scattered showers and isolated storms will continue to move northwest across the waters. Winds south to southeast around 10 knots. Seas 2 to 3 feet. Rip Currents: Moderate risk expected for Thursday. && .PRELIMINARY POINT TEMPS/POPS... AMG 71 91 73 91 / 20 20 30 30 SSI 75 87 76 88 / 20 20 20 30 JAX 73 90 74 91 / 40 20 20 20 SGJ 75 87 74 88 / 40 30 20 20 GNV 72 90 73 90 / 50 60 20 40 OCF 72 90 73 91 / 60 60 20 40 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ PP/NM/KB
Area Forecast Discussion
National Weather Service Louisville KY
835 PM EDT Wed Aug 29 2018 .Forecast Update... Issued at 830 PM EDT Wed Aug 29 2018 Diffuse surface front is currently draped WSW to ENE across Kentucky and isn`t expected to move much overnight. This area is in a gap between the progressive impulse pushing well into the eastern Great Lakes, and another slower-moving disturbance supporting convection over the Ozarks. This trend is not well handled by the synoptic models. Hi-res models tell a different story, with the SPC HRRR continuing to show convective regeneration across south-central KY beginning around 03Z, and then expanding NE overnight. With this in play, we can`t rule out storms overnight, especially south of the Western Kentucky and Bluegrass Parkways. However expect these to be garden- variety storms with minimal SVR threat as the shear is weak and the instability will be nearing diurnal min. && .Short Term...(This evening through Thursday) Issued at 220 PM EDT Wed Aug 29 2018 A surface analysis this afternoon showed low pressure over the eastern Great Lakes region with a cold front extending southwest through Ohio, central Indiana, and southern Illinois. Ahead of this boundary, warm and moist air prevailed. GOES-16 sounder data suggests PWATs are running 1.6 to 1.7 inches while regional observations show dewpoints in the lower to middle 70s. Recent RAP mesoanalysis puts MLCAPE values of around 2000 J/kg. Scattered showers and storms have be forming since early this morning along and ahead of the surface boundary. The forecast in the near term is a bit unsettled with the front expected to slowly sag into central Kentucky this evening and stall/wash out across the area through Thursday. For the remainder of this afternoon, a few stronger storms will be possible across southern Indiana and north central Kentucky where the pool of MLCAPE is expected to be the highest. DCAPE values of around 1000 J/kg also suggest the potential for wet microbursts. There is a threat of heavy rain given the high PWATs, especially if storms train over the same areas. There will be a downward coverage trend with convection by early this evening with the loss of daytime heating but the atmosphere will remain unstable through tonight given the front in the vicinity, so will maintain a 20-30 percent chance of showers into Thursday morning. Forecast soundings and time heights show pooling of low level moisture across the area which could end up being a thick stratus layer by sunrise Thursday. These low clouds could hang around for much of Thursday morning, especially along/north of the KY Parkways. Showers and storms on Thursday will be mainly confined to south central and central Kentucky (generally along/south of the front). No organized severe weather is anticipated but if instability builds due to clearing skies then a few stronger storms producing gusty winds are possible. Highs will be closer to normal with the clouds and threat of rain and are expected to top out in the lower to middle 80s. .Long Term...(Thursday night through Wednesday) Issued at 210 PM EDT Wed Aug 29 2018 Thursday night, our region will be between two ridges, one centered over near TX and the other the typical Bermuda High. In between is a weak col, with a surface front also either over or just south of south central KY. Drier air will try and filter into our southern IN and north central KY stations, but won`t last too long. Rain chances will be limited to closer to the TN border. Friday, the western ridge weaken a little as a broad trough moves in from south central Canada. We still could have a pocket of drier air over the region, but the cooling heights aloft may allow for more storm coverage up to the Ohio River. Pattern should persist to Saturday. From Sunday on, our forecast still depends on the strength and location of the Bermuda High in our area. 00Z Euro has that ridge axis right over us, even on Saturday afternoon to perhaps a little north of the region by midweek. 00Z GEFS is similar in location, with mean QPFs all less than a tenth of an inch, a usual indicator of widely scattered to isolated storm coverage. Will keep lower pops, a little under the blended guidance. && .Aviation...(00Z TAF Issuance) Issued at 710 PM EDT Wed Aug 29 2018 Pre-frontal trof has pushesd into the Ohio Valley, with southern Indiana and central Kentucky sitting in a gap in the convection. Will initialize with just cirrus ceilings as diurnal Cu dissipates around sunset. Hi-res models continue to develop showers and a few storms along the slow-moving boundary overnight, but forecast confidence is low, so will only carry VCSH and high-end MVFR ceilings in BWG and LEX for now. By Thu morning, a shallow and slightly cooler air mass will try to nose southward into HNB and SDF. However, with only a minimal drop in sfc dewpoints stratus/fog are a definite concern. Will hit HNB the hardest with several hrs of IFR ceilings and vis, while the heat island keeps SDF in MVFR but still fuel-alternate. Look for a gradual improvement to at least high-end MVFR by the afternoon. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...RAS Short Term...ZT Long Term...RJS Aviation...RAS
Area Forecast Discussion
National Weather Service Marquette MI
717 PM EDT Wed Aug 29 2018 .SHORT TERM...(This evening through Thursday) Issued at 400 PM EDT WED AUG 29 2018 WV imagery and RAP analysis indicated a low amplitude pattern with a shallow mid/upper level trough from nrn Ontario into the nrn Great Lakes. At the surface, high pressure over the Upper Mississippi valley was gradually building into the region with drier air filtering into Upper Michigan on anticyclonic northwest flow. However, leftover low level moisture and 850 mb temps near 5C supported abundant cu/sc over the area with some clearing only gradually moving into the west. Tonight, Satellite trends and low level RH forecasts suggest that clouds should continue to clear and thin out the rest of the afternoon into the evening. With mostly clear skies and diminishing winds, favorable radiational cooling conditions (PWAT values below 0.50 inch) should allos temps to drop toward the lower end of guidance with inland readings to around 40. Some mid 30s may be possible in isold traditional cold spots. Patchy fog should also develop inland that may become locally dense. Thursday, Mostly sunny skies will boost temps to around 70. Light southerly winds developing as the high moves off to the east will lake breezes to develop. .LONG TERM...(Thursday night through Wednesday) Issued at 354 PM EDT WED AUG 29 2018 Active weather with multiple rounds of showers/t-storms could affect Upper Michigan Fri through next Tue. Decent agreement from the models that best chances for rain over Upper Michigan are Fri-Fri Night and again late Tue into Tue night. Some potential late Sun through Mon period could also be active depending on where more active west to east oriented frontal boundary and associated moisture advection and instability gradient develops. PWATS with initial system Fri night are around 1.5 inches but these values climb to around 2 inches by early next week along the frontal boundary. Through this time frame it is certainly reasonable some areas in the region will see heavy rain along with possible severe weather. Fri-Sat...Broad troughing aloft approaching Upper Great Lakes on Fri dampens out on Sat. Main sfc trough slowly approaches by Fri night exiting south and east on Sat afternoon. May see showers/t-storms as early as Fri morning over western Upper Michigan due to warm air and moisture advection. Strongest advection will remain well southwest of Upper Michigan though. Forecast soundings indicate that initial activity may fall apart while heading into central Upper Michigan by Fri afternoon. Could be just lower clouds with light showers or sprinkles, though not quite sure on that yet. Based on possible lower clouds, only increased temps toward upper 70s over far east where there could be some sunshine early in the day. Another round of showers/t-storms probably develops along trough Fri evening or Fri night though greater instability is forecast to remain south into WI with low-level jet veering SW to WSW after midnight. Right entrance of jet streak aloft could support rain farther north than that but could see the thunder chances ending up on the lower side. SPC Day3 outlook clips western Upper Michigan with marginal risk on Fri/Fri night with greater risk farther south and west. Lingering rain should be mostly over east half of U.P. on Sat morning with drying trend into western U.P. Temps mainly in the 70s for the day but could be cooler along Lk Superior if stronger NW winds develop behind the trough. Sun-Labor Day...Think most of Sun ends up dry as ridging briefly returns. Better chance of sunshine and winds mainly southerly so raised temps over consensus into the upper 70s/near 80F. Some pop- up showers may develop as previous EC showed, but think if rain occurs it likely holds off til Sun night. 12z GFS looks quite aggressive compared to recent GFS runs along with other models and GEFS in bringing mid level moisture advection and resulting heavier swath of QPF of 1-2 inches into western Upper Michigan Sun night into Mon. More likely scenario is scattered showers and t-storms mainly over southern Upper Michigan along stronger dwpnt/instability gradient. Seems that whatever is around late Sun night moves out early on Labor Day. Suppose we cannot rule out pop up showers/t-storms in the aftn on Labor Day as front/edge of instability will be just to the south with dwpnts pushing toward 70F into that boundary. Weak winds could also result in lake breezes which may help trigger a shower or t-storm during peak heating. With more clouds and front close by, expect high temps on Labor Day generally in the low to mid 70s. Tue-Wed...Stronger low pressure system and sfc trough comes in later Tue into Tue night. Higher dwpnts/PWATs pool ahead of that system which could set stage for stronger t-storms and increased potential of heavy rain. Still differences in main upper level pattern/timing of trough which will no doubt affect coverage and intensity of t-storms but Tue does look like a day that bears watching in terms of t-storms/heavy rain. Decent agreement high pressure eventually builds back over region by middle of next week but not sure if that occurs Wed or Thu so will keep low chances for showers along with smaller risk of t-storms in forecast for Wed. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 705 PM EDT WED AUG 29 2018 Drier air filtering into the area associated with building high pres from the west, has finally allowed low clouds to clear out of KSAW in the past hour or two. Fog is expected to develop late tonight, and may become locally dense over the interior west but should generally remain inland from the TAF sites. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 400 PM EDT WED AUG 29 2018 Winds will diminish tonight, and will remain at or below 15 knots until late Thursday evening, when they will increase up to 20 knots by early Friday morning across much of the lake and 25 knots Friday night over the east half. Winds will then remain below 15 knots until Tuesday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Beach Hazards Statement until 8 PM EDT this evening for MIZ005- 006. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...Voss MARINE...JLB
Area Forecast Discussion
National Weather Service Paducah KY
656 PM CDT Wed Aug 29 2018 .UPDATE... Issued at 655 PM CDT Wed Aug 29 2018 Updated the forecast to substantially lower the chance of showers and thunderstorms tonight. With the loss of daytime heating and corresponding atmospheric stabilization already underway, the thunderstorm potential appears to be very slim at this point. However, the HRRR still signals some potential for redevelopment this evening, especially in western Kentucky. It`s hard to argue completely against keeping a slight chance with a weak frontal boundary making passage. Anything that occurs should be during the evening, with dry weather expected overnight. Added a mention of patchy fog late tonight and early Thursday morning with the aviation forecast package, and this will be reflected in the ZFP shortly. Remainder of forecast is unchanged. Also updated aviation discussion for 00Z TAFs. && .SHORT TERM...(Tonight through Friday night) Issued at 203 PM CDT Wed Aug 29 2018 Fair confidence in the short term. Models have a wide range of solutions in the short term but a chance of rain or storms can not be ruled out. Most of the CAMS have us getting very little rain but the HRRR is probably the one with the most qpf. The NAM has absolutely the most qpf of any of the models but it indicates this evening is the best time. With the loss of heating find this solution difficult to accept. A cold front is expected to move into the area today and this evening which would be the focus for storm development. It may stall over the southern portions of the area or make it just south into TN overnight. Any storms that do fire this afternoon will have the potential to be strong or even isolated severe. The GFS seems too extreme with its severe parameters. However the NAM does indicate LI`s to negative 7 and CAPES of 2k 3k j/kg2. Also shows PWATs exceeding 2 inches. The wind profiles are somewhat benign and the freezing level is around 15k feet. So the main threat with any storms would be wind/downburst and heavy rain. With the loss of heating I expect convection will end overnight. Friday the cold front starts to lift back north as a warm front returning storm chances to the area once again Friday. Severe weather is not expected with this feature. Then once again rain chances diminish as we lose the heating Friday evening. Thursday temperatures will be near normal after Thursday temperatures will return to above normal. .LONG TERM...(Saturday through Wednesday) Issued at 203 PM CDT Wed Aug 29 2018 The long term portion of the forecast will be dominated by a summer like synoptic pattern, with High pressure aloft over the southern and/or eastern CONUS for the duration of the period. Heat/humidity underneath the High will be sufficiently summer like as well, with near daily Highs/Lows around 90/70, or within a degree or two each day. Rimfire convection and/or diurnally driven convection when/where the High aloft, or reflected surface High, is not directly overhead will also be a daily occurrence. This should keep daily storm hazards mainly lightning/locally heavy rain, and overall, daily storm chances low. There is little to suggest any other pattern change for the foreseeable future, so summer-time continues into September and thru the Labor Day Holiday weekend. && .AVIATION... Issued at 655 PM CDT Wed Aug 29 2018 Removed all mention of precipitation from forecast terminals as any additional potential appears to be more probable south and east of the terminal locations. While VFR conditions are forecast through much of the period, guidance suggests the potential for MVFR and possibly IFR ceilings and/or visibilities late tonight and early Thursday morning. Lingering fog should burn off by mid morning, but MVFR ceilings may linger through late morning before lifting to VFR in most locations by afternoon. Winds will become light northerly behind the front tonight, then northeast around 5 knots on Thursday. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ UPDATE...RJP SHORT TERM...KH LONG TERM...DH AVIATION...RJP
Area Forecast Discussion
National Weather Service Pueblo CO
257 PM MDT Wed Aug 29 2018 .SHORT TERM...(This evening through Thursday) Issued at 236 PM MDT Wed Aug 29 2018 An upper level ridge will remain centered over NM tonight through Thu, keeping the weather mainly dry. Late tonight some high level clouds are expected to move over southern CO. On Thu, the NAM shows the potential for a couple spots of precip over some of the mtns in the afternoon and the HRRR is dry. Will not mention any chance for precip in the forecast. Temps will be warmer on Thu, with 90s over most of the plains and lower to mid 80s in the San Luis Valley and the Upper Arkansas River Valley. .LONG TERM...(Thursday night through Wednesday) Issued at 236 PM MDT Wed Aug 29 2018 There is quite a bit of uncertainty with the evolution of the upper pattern through the extended period. Both the operational GFS and ECMWF similar in that they both have varying degrees of troughing over the western states and high pressure along the east coast. Ensembles have a high spreads leading to reduced confidence in the evolution of the extended forecast. Thursday night...generally dry conditions are expected across the region while a weak disturbance tracks across northeast Colorado. This may help generate isolated thunderstorms over the Palmer Divide during the evening hours, which will shift east and dissipate with sunset. Overnight lows will fall into the upper 50s to lower 60s for lows. Friday...models in decent agreement with an upper trough digging south across the Great Basin and flow turning more southwesterly across Colorado. A weak upper disturbance is forecast to move across the region during the afternoon and evening hours, while a cold front drops south across the Plains by the evening. A slight increase in moisture will likely lead to shower and thunderstorm development over the mountains during the afternoon, while the front generates thunderstorms into the evening hours. For the most part, expect showers and thunderstorms across the Plains to remain south of Highway 50. Temperatures will be hot across the area with mid 90s over the lower elevations. Saturday through Wednesday...by Saturday, the broad upper trough will drop south into the Desert Southwest and take up residence there. This will keep flow aloft southwesterly. Several embedded disturbances are forecast to move across the area through this period. The GFS has strong waves moving north out of New Mexico on Saturday, Sunday and Tuesday, each leading to widespread shower and thunderstorm coverage across the region. Locally heavy rainfall will be possible and flash flooding on area burn scars will have to be watched. Lightning and gusty outflow winds will also be concerns. Temperatures will be cooler over the region with generally mid 80s across the Plains. The ECMWF is similar to the GFS with weak troughing over the western states, however, has much weaker disturbances lifting north across Colorado. While showers and thunderstorms can still be expected, coverage does not appear to be as great as the GFS. Mozley && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 236 PM MDT Wed Aug 29 2018 VFR conditions are expected the next 24 hrs at KALS, KCOS, and KPUB. The winds will decrease this evening, and then late tonight, high level clouds are expected to move over southern CO. Breezy southwest winds are expected at KALS Thu afternoon, with breezy south winds at KCOS and KPUB. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...28 LONG TERM...MOZLEY AVIATION...28
Area Forecast Discussion
National Weather Service Tallahassee FL
829 PM EDT Wed Aug 29 2018 .UPDATE... This evening rain and thunderstorms will be slow to dissipate. In the early morning hours showers and storms will form near the coast and over the Gulf. No significant changes were made to the overnight forecast. .AVIATION [Through 00Z Friday]... Inland convection will continue to gradually diminish through the evening hours. Some low ceilings are expected to develop late tonight through the mid-morning hours Thursday with MVFR to perhaps IFR conditions. Scattered convection is expected again for Thursday afternoon. && .PREV DISCUSSION [745 PM EDT]... .NEAR TERM [Through Tonight]... Local radars show convection increasing rapidly across the Florida panhandle and Big Bend early this afternoon. Also, additional showers and thunderstorms from the east coast sea breeze are approaching from the Suwannee Valley. Looks like a very active remainder of this afternoon with the HRRR showing convection continuing at least into late evening much like we saw yesterday. Likely PoPs across the Big Bend and portions of the panhandle until 06z with chance PoPs elsewhere. Lows in the lower to mid 70s. .SHORT TERM [Thursday Through Friday Night]... Through the end of this week, the persistent ridge of high pressure that has been residing just east of the mid-Atlantic states will continue to produce moist east and southeasterly flow. This will keep scattered showers and thunderstorms in the forecast each afternoon along with enhanced coverage along the Gulf and Atlantic seabreezes as they move north and west respectively. Meanwhile, during the early morning hours coverage of showers and thunderstorms will be more likely over our coastal waters. .LONG TERM [Saturday Through Wednesday]... The synoptic pattern for the rest of the forecast period will remain very similar. The aforementioned ridge of high pressure will continue to produce large scale easterly and southeasterly flow. This setup will allow for increased rainfall chances slightly- above normal and temperatures at or slightly below seasonal levels due to enhanced cloud coverage. The NHC is currently monitoring a tropical disturbance located near the Lesser Antilles. This system will move northwest towards the Bahamas for the next few days. .MARINE... East and southeast winds around 10 knots along with seas around 1 to 2 feet is expected today and tonight. Winds pick up slightly through the rest of the week and into the weekend with winds ranging from 10 to 15 knots and seas increasing to around 2 to 3 feet. Expect scattered to widespread showers and thunderstorms through the next week with most activity tied to the morning and early hours. .FIRE WEATHER... Low dispersions less than 20 are possible tomorrow afternoon. Patchy fog is possible in the early morning hours. .HYDROLOGY... The active convective pattern will continue through the period with increased chances of showers and thunderstorms expected over the CWA during the afternoon hours. Although widespread precipitation is not expected, given the current moist regime slow moving moving storms with high rain rates could cause localized flooding in low- lying and poor-drainage areas. .SPOTTER INFORMATION STATEMENT... Spotter activation is not requested. However, spotters are always encouraged to safely report significant weather conditions when they occur by calling the office or tweeting us @NWSTallahassee. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 72 86 73 89 73 / 40 50 30 40 20 Panama City 74 86 73 87 75 / 40 50 40 50 30 Dothan 72 87 71 89 71 / 40 50 20 40 20 Albany 72 90 72 90 73 / 50 50 20 40 20 Valdosta 72 89 72 90 72 / 50 40 30 40 20 Cross City 73 89 73 90 74 / 40 50 30 40 30 Apalachicola 76 85 75 86 77 / 50 50 40 40 30 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ UPDATE...McD NEAR TERM...Barry SHORT TERM...DiCatarina LONG TERM...DiCatarina AVIATION...DVD MARINE...DiCatarina FIRE WEATHER...McD HYDROLOGY...DiCatarina