Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/27/19

Area Forecast Discussion
National Weather Service Cleveland OH
948 PM EDT Mon Aug 26 2019 .SYNOPSIS... A warm front will lift north across the area tonight as low pressure tracks east across Ontario. The low will deepen and track to Hudson Bay Tuesday into Wednesday, forcing a cold front east across the area. A secondary trough will move east through the Great Lakes on Wednesday. High pressure will build northeast across the region Wednesday night through Thursday night. && .NEAR TERM /THROUGH TUESDAY/... Update...Made small changes to pops and weather overnight into Tuesday based on current trends and the HRRR output. Dry slot is working into the area from the west a bit ahead of schedule but HRRR suggests showers will also return west before dawn. Also, for the beaches, considered a beach hazards statement but since higher waves will be off shore tonight and Tuesday, decided against it despite the small craft headline. Did however boost the swimming risk to moderate Tuesday for all beaches. Original...Showers continue to overspread the area this afternoon from the southwest as a warm front lifts northeast into the area. Went with categorical pops west/likely pops east through the evening, with a gradual lowering of pops after midnight from west to east as some mid level drying moves northeast into the area and low level forcing moves out of the area. A lull in the precip activity overnight will continue into Tuesday morning before a cold front moves into the area during the afternoon/evening hours. More convective showers, perhaps some thunderstorms with weak instability building northward ahead of the front, will overspread the area west to east after 18Z through the evening/into the overnight. Have a corridor of high likely pops tracking east across the area late afternoon into the overnight hours Tuesday night. The front will push east of the area late Tuesday night into very early Wednesday morning. Lows tonight will be a little warmer and more humid than previous nights, with low to mid 60s expected. Highs Tuesday will range from the mid 70s east to the low 80s west. Low Tuesday night will be slightly cooler and drier behind the front, with low 60s expected. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... A sharp upper level trough will be moving across the Great Lakes Region. A decent surface high pressure system will be building across the Midwest Region on Wednesday. The surface gradient of low pressure over Ontario and the high pressure over the Midwest will develop gusty westerly winds over the area Wednesday. Westerly winds will be around the 10 to 20 mph range. We will see a drier airmass filtering in to the area but temperatures will be just a tad cooler and slightly below averages. As colder air aloft at 850 to 700 mb moves over Lake Erie, some lake effect clouds and a few lake effect showers will be possible Wednesday evening through Thursday morning. The upper level trough become flatten out by Thursday evening. Another cold front will move along with the westerly mid level flow and push through late Thursday night into Friday morning. There may be enough lift and limited moisture to squeeze out clouds and a few showers with the front. Another weak Canadian high pressure builds in for Friday afternoon. && .LONG TERM /FRIDAY THROUGH MONDAY/... A cooler airmass builds in Friday night with a high pressure area coming down from Ontario. Overnight lows away from the lake will be down in the lower to middle 50s. A shortwave will move along the 500 mb westerly flow late Saturday and Saturday night with some clouds and a chance for scattered showers. There is some uncertain with timing amongst the model data as the EURO is a little slower on timing. We will continue to stay in a slight west or northwest flow into early next week with off and on chances for clouds and a few showers. && .AVIATION /00Z Tuesday THROUGH Saturday/... The evening begins with IFR CIGS far west and VFR conditions east. Warm frontal showers will continue to lift north across the area this evening as lowering CIGS drift east. While precip will likely taper off from late evening into the early overnight, CIGS will likely remain restricted with MVFR visibilities in patchy fog and lingering scattered showers. Tuesday expect continued widespread MVFR conditions. Showers and a few thunderstorms will develop and move west to east across the area along and ahead of a cold front. OUTLOOK...Areas of Non-VFR Tuesday night, lingering across far eastern OH/nw PA into Wednesday. && .MARINE... A deepening area of low pressure over the northern Great Lakes region tonight will continue to move into Ontario overnight. A decent low level jet will develop around 925 mb overnight into Tuesday morning. Gusty southerly winds will develop over the lake this evening through at least Tuesday afternoon. South winds 20 to 25 knots will be likely with wind gusts up to 35 knots possible. We have issued Small Craft Advisories late this afternoon through early Tuesday afternoon for these strong gusty winds. Because of the offshore nature of the wind, waves will be generally between 1 and 3 feet. A front will move across the lake Tuesday afternoon with winds shifting to the west 10 to 15 knots by Tuesday evening. Gusty westerly winds increase 15 to 25 knots will develop on Wednesday and Wednesday night with additional Small Craft Advisories likely be needed. Southwesterly winds will be the expected with increasing wind speeds late Thursday and Thursday night ahead of another cold front. Winds may increase 20 to 25 knots again and more advisories will likely be needed again. Another front will move through on Friday with a shift to northerly or northwesterly winds. The main story on the lake this week will be strong gusty winds shifting with several fronts and building high pressure systems. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Small Craft Advisory until 5 PM EDT Tuesday for LEZ142>149. && $$ SYNOPSIS...Greenawalt NEAR TERM...Greenawalt/TK SHORT TERM...Griffin LONG TERM...Griffin AVIATION...TK MARINE...Griffin
National Weather Service Kansas City/Pleasant Hill MO
1035 PM CDT Mon Aug 26 2019 .Discussion... Issued at 241 PM CDT MON AUG 26 2019 The morning/early afternoon thunderstorms that moved through eastern KS and western MO have really altered the environment for any potential afternoon storms. With the storms still going strong south of the forecast area, there is a substantial cirrus shield. There is also a lower level of stratus across east central/northeast KS and northwestern MO that, based on satellite imagery, doesn`t appear to be eroding with any haste. Lastly, the airmass has been stabilized by the storms that went through and because the cloud cover is lingering well into the afternoon, the chance to recover and destabilize is becoming worse with every hour. With that said, there is still strong upper level flow moving into the area associated with an upper trough moving across the northern Plains. This upper system will push a cold front through the area later this afternoon and this evening. With the forcing associated with the front and upper-level shortwave, we should still be able to see scattered to maybe widespread showers and few storms develop. But the lack of instability should keep the severe weather chances lower and really confined to areas south of Highway 50, or even south of the forecast area. The RAP and the HRRR, which finally started to resolve the MCS, show the far southern portions of the forecast area building instability as the front moves into that area around 23Z this afternoon. 19Z observations show very warm temperatures and dewpoints in southeastern KS and southwestern MO. So there isn`t a great distance from weak instability to extreme instability. A little northward advection of this and it`s in the southern portions of the forecast area, like the RAP and the HRRR show. Given this, can`t rule out a severe storm in our far southern counties later this afternoon or early this evening as the front is moving through. Dry weather with cooler than normal temperatures is expected through at least Thursday. Thunderstorm chances return Friday as a surface boundary stalls in the area and a mid-level shortwave moves east across KS. Those chances may linger into Saturday but by Sunday into Monday, it looks like we are back into the cooler, drier weather pattern prevails again. && .Aviation...(For the 06Z TAFS through 06Z Tuesday Night) Issued at 1032 PM CDT MON AUG 26 2019 A cold front has pushed through the area and cleared out the area of the MVFR ceilings. This has created clear skies with light winds and dropping temperatures, but not dropping dewpoints. Due to this we are going to see a few hours of fog potential over the region before the drier dewpoints upstream in Nebraska can make their way into the area around 09Z. I`ve added some MVFR visibility to account for this with some LIFR visibility around KSTJ as they tend to go down quickly with the warmer Missouri River nearby. Once these drier conditions make their way into the area things should stay VFR from there. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ Discussion...CDB Aviation...Barham
Area Forecast Discussion
National Weather Service Green Bay WI
1054 PM CDT Mon Aug 26 2019 Updated aviation portion for 06Z TAF issuance .SYNOPSIS... Issued at 227 PM CDT Mon Aug 26 2019 Showers continuing tonight, then a couple days of blustery weather mid-week. Quieter conditions will settle into the area for the end of the week and start of the Labor Day weekend. Large scale amplification will continue the next few days as the upper trough progressing into the region deepens and closes off into an upper low over western Ontario. The upper flow will flatten later in the week as the bulk of the energy within the trough lifts into northeast Canada. That will result in rising upper heights and a weakening of the cyclonic upper flow across the area. The ongoing precipitation event will account for the bulk of the precipitation that occurs during the period. After that moisture will be limited, so subsequent precipitation events will likely generate scattered light to moderate amounts. Totals for the whole period will probably be near to slightly below normal. A few days ago, it seemed that generally below normal temperatures would be likely after today. It now appears there will be more significant day-to-day variation (cool Wednesday, warmer Thursday, then cooler again Friday and Saturday). It still appears as though readings will probably end up near of slightly below normal for the period as a whole. && .SHORT TERM...Tonight and Tuesday Issued at 227 PM CDT Mon Aug 26 2019 The latest RAP analysis and satellite/radar imagery show an area of low pressure over northwest Illinois, and an associated warm front extending east across northern Indiana. Several embedded shortwave impulses are sliding north into the region ahead of the low and generating widespread light to moderate rain over much of eastern WI. Meanwhile, a cold front is moving east across Minnesota, with another band of showers and isolated storms along it. As these systems move across the region, precip trends and the possibility of strong storms on Tuesday afternoon are the main forecast concerns. Tonight...The low pressure currently over northwest Illinois will lift northeast and across northeast WI this evening. The main area of rain will continue to shift with the low and exit far northeast WI by midnight. Not out of the question that a rumble of thunder could impact the lakeshore areas until that time, as there are decent radar returns offshore of Sheboygan. With pwats upwards of 1.8 inches, the rainfall will likely be quite efficient and could therefore look at precip totals upwards of 1 inch at some areas. Looking to the west, a solid band of rain will be heading east across the state ahead of a cold front. Most models have this rain band thinning out as it approaches north- central WI by mid- evening. This makes sense in that the forcing via mid- level fgen will weaken as it lifts north into Lake Superior. Elevated instability also is projected to weaken at the same time. Otherwise, should see a cloudy night with lows not falling much into the upper 50s to lower 60s. Tuesday...Winds will turn to the west behind the cold front and becoming gusty during the morning. The influx of drier air and downsloping should lead to partial clearing over eastern WI first during the morning, while north-central WI will be slower to clear. With upper troughing over the northwest part of the state, a potent shortwave will move into Wisconsin during the afternoon. Steepening mid-level and low level lapse rates will result in instability growing to above 500 j/kg in the mixed layer. If it weren`t for the lack of moisture through the column, storms would be a higher bet. Will show storm chances spreading from northwest to southeast through the afternoon. Given the cool temps aloft, could see some brief gusty winds and small hail in any storms. Temps returning to the upper 60s to mid 70s. .LONG TERM...Tuesday Night Through Monday Issued at 227 PM CDT Mon Aug 26 2019 Relatively deep mixing into unidirectional westerly flow will result in gusty winds and blustery conditions during the daytime on Wednesday. Periods of showers are likely mid-week as shortwaves rotate through the area. Although those will be difficult to time, there should also be a diurnal component to the showers so adjusted PoPs and Sky grids with that in mind. A more substantial shortwave pushing across southern Canada mid-week will likely generate a surface reflection. Southwest winds ahead of that feature will bring milder air into the area, resulting in a warmer day on Thursday. Cooler air will settle into the area in the wake of the feature and linger into the start of the weekend as an anticyclone from southwest Canada settles into the region. Overall, the default forecast initialization grids based on a broad-based blend of guidance products seemed reasonable. Some adjustments were made to PoPs and Sky grids for the first few days of the long-term portion of the forecast to account for clouds/showers expected to shift across the area as shortwaves rotate around the base of the deepening upper trough. && .AVIATION...for 06Z TAF Issuance Issued at 1054 PM CDT Mon Aug 26 2019 IFR conditions will continue overnight as a low pressure system continues to bring rain showers to the area as a cold front slides through the area. Behind the cold front, slowly improving cigs are likely over the Fox Valley and Lakeshore late tonight, but central and north-central WI areas may have to wait until Tuesday morning for the improving conditions. With partial clearing, gusty west winds are expected to develop by midday Tuesday, with more storms possible on Tuesday afternoon. The best chance for storms Tuesday afternoon will be across north-central and central Wisconsin. Farther east the chances are too low to include in this set of TAFs. && .GRB WATCHES/WARNINGS/ADVISORIES... Beach Hazards Statement until 7 AM CDT Tuesday for WIZ022-040- 050. && $$ SYNOPSIS.......Skowronski SHORT TERM.....MPC LONG TERM......Skowronski AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Grand Rapids MI
1034 PM EDT Mon Aug 26 2019 LATEST UPDATE... Update .SYNOPSIS... Issued at 330 PM EDT Mon Aug 26 2019 -Rain showers tonight into Tuesday morning -Dangerous swim conditions Tuesday, worse Wednesday -Beach erosion and lakeshore flooding possible Wednesday -Temperature mostly below normal through Labor day && .UPDATE... Issued at 1035 PM EDT Mon Aug 26 2019 Little question it will continue to rain across the area through midnight or so. However based on SPC Mesoscale Analysis at 10 pm, there clearly is very little instability for thunderstorms. Monitoring our radar echos near the -10c isotherm, none of the echos that reach that level have been strong enough for lighting production. Since the 9 pm run of the RAP model had the most unstable cape below 200 j/kg as the upper wave tracks across our CWA and we are in the right exit region of the incoming upper jet, all of these things tell me thunderstorms are rather unlikely. So I have taken them for the most part out of the forecast. I did leave a small chance near I-94 for a few hours just in case. Otherwise the on-going forecast is doing nicely. Most of the rain should be east of our CWA by 2 - 3 AM this morning. && .DISCUSSION...(This evening through next Monday) Issued at 330 PM EDT Mon Aug 26 2019 Showers expected to become more numerous this evening as negative tilt shortwave lifts northeast from nrn Illinois. Can`t rule out an isolated tstm tonight, but not much lighting has been noted upstream today and cape progs are not impressive. The RAP and NAM do however show 600-800 J/KG capes after midnight. Although an extremely low probability scenario, it should be noted that a brief spin up tornado or two cannot be ruled out tonight. Tremendous low level wind shear exists thanks to backed /southeasterly/ sfc flow and increasing SSWly low level just above the sfc. If any sfc based instability can sneak into Southwest Michigan tonight it`s possible that even a rain shower could drop a quick, weak tornado. best time frame would be 00Z to 06Z, but again this is a really low possibility. Also still can`t rule out some locally heavy rainfall amounts of up to two inches tonight, although confidence in that is low since model qpfs have trended down a bit. Looks like we dry out Tuesday afternoon and sunshine emerges as dry slot sweeps in from the west, although perhaps some gusty winds to 25 mph developing once deeper mixing develops. We may flirt with 80 degrees, especially from GRR south and east, since the good cold advection holds off until late Tuesday night-Wed. Cooler and breezy as main upper trough arrives late Tuesday night and Wednesday. This should also lead to increasing cloudiness with some isolated showers possible. We begin warm advecting again on Thursday, then another cold front brings a chance of rain on Thursday night. Cooler than normal temps expected as we move into Labor Day weekend but only low precipitation probabilities at this point. Latest ECMWF wants to generate some rain on Sunday south of I-96 as a wave moves along the sfc front which will be south of MI. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 745 PM EDT Mon Aug 26 2019 Expect for the most part IFR conditions through 12z as the frontal system moves through the area. There is a large area of IFR cigs over most of central and southern Lower Michigan at 00z that extends south into Ohio and eastern and central Indiana. There is also a band of convection moving east over Lake Michigan that will move through all of the TAF sites in the 01z to 06z time frame with rain that may be heavy at times. Surface winds will remain gusty until the back edge of the rain band moves through and winds will be lighter and more from the south. The cold front will come through during the mid morning hours and may have a few showers with it. After it comes through winds will turn more westerly and skies will clear rather quickly. && .MARINE... Issued at 330 PM EDT Mon Aug 26 2019 Have extended beach hazard statements and small craft advisories into Wednesday, which looks like the worse of the next two days. In fact we may also need lakeshore flood advisories for wednesday to highlight the high risk of beach erosion. Current strong southeast flow goes southerly tonight then west-southwest for Tuesday. The flow on Wednesday will be westerly which is a prime direction for some erosion issues with waves near 8 feet forecast. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement from 6 AM EDT Tuesday through Wednesday evening for MIZ064-071. Beach Hazards Statement through Wednesday evening for MIZ037-043- 050-056. LM...Small Craft Advisory until 8 PM EDT Wednesday for LMZ844>849. && $$ UPDATE...WDM SYNOPSIS...Meade DISCUSSION...Meade AVIATION...WDM MARINE...Meade
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
943 PM CDT Mon Aug 26 2019 .UPDATE... 943 PM CDT Showers and isolated t-storms have generally pushed south and east of our CWA as of mid evening. Can`t rule out an isolated shower or two the rest of tonight, especially far southern CWA, as the main upper trough moves through the region, however guidance has largely trended dry tonight. In addition, DVN sounding this evening confirmed what GOES water vapor imagery depicts, and that is an abundance of dry air in the mid-upper levels. Given this data, have removed precip chances over most of the CWA for the remainder of tonight, the one exception being very far southern portion of the area where I hung on to some chance pops in case some showers develop northward as weak shortwave trough in MO moves eastward. - Izzi && .SHORT TERM... 235 PM CDT Through this afternoon... Showers have expanded in coverage early this afternoon as a surface circulation tracks northeast across north-central Illinois. This has pushed a warm frontal boundary further north into the area. Low level instability is maximized ahead of the surface low with decent low level shear in place as well. Some of the better organized showers have exhibited some weak low level rotation across Kane Co. which may be due to somewhat better low level convergence with south-southeast winds across much of the Chicago metro. Better overall instability is to the south and supportive of stronger updrafts but low level convergence is less favorable. Best potential for lightning is to the south. A low chance for an isolated funnel or perhaps brief tornado is probably between the I-80 and I-90 corridors with somewhat deeper showers but this chance is pretty minimal. Decent rainfall is also occurring with the very moist airmass with radar estimates of around 0.5 in/hr with some isolated amounts closer to 0.75-1.0/hr likely occurring. The bulk of the activity should exit to the east and northeast late this afternoon. MDB && .LONG TERM... 235 PM CDT Tonight through Monday... The second of two shortwaves embedded within the larger scale cyclonic flow aloft will be approaching the area this evening then gradually swinging through overnight. Presently the activity associated with this wave is focused in two different areas. To the north and closer to a surface low over Manitoba is a line of convection along a cold front pushing through Minnesota and northern Iowa. Farther south near another low center, or more of a meso-low, over Missouri is a line of stronger convection that dropped out of Nebraska and is moving southeast. In between, the low level convergence appears much more marginal. It is possible that portions of the forecast area will not see additional showers and thunderstorms as the frontal zone moves through tonight. This is actually the scenario depicted by the HRRR which seems to be handling the existing activity reasonably well and favors southern portions of the forecast area as being most likely to see later development. All of this thinking appears to align with existing forecast trends which show a break in activity toward early evening and then an uptick overnight and into the predawn hours Tuesday, mainly south. Tuesday morning the cold front pushes off to our east which should bring an end to any lingering shower activity. High pressure then settles in at the surface and keeps a lid on additional development until late in the week. The exception could be Wednesday afternoon when the longwave trough axis pushes through overhead and low levels become well mixed on the northeast periphery of the surface high. The GFS and ECMWF both hint at some afternoon showers just to our north, farther from the influence of the ridge, but forecast soundings over the local area suggest development would be limited to the boundary layer. Even so, both Wednesday and Thursday appear to be well mixed at the surface and tapping into some stronger gust potential from 20+ knot westerlies just above the boundary layer. Confidence decreases from late week into the holiday weekend, though deterministic NAM/GFS/ECMWF solutions all agree in pushing the next frontal zone toward the region by late Thursday or more so into Thursday night. Ahead of this feature, Thursday appears to be the warmest and most humid day of the week, though heat indices only top out in the low to mid 80s. The GFS/ECMWF then drop the front south of the area for the late week and early weekend with another high settling overhead. If it drops far enough south, this would bring a brief period of showers or thunderstorms on Thursday night then keep at least Friday and the early part of Saturday dry. However, if the front stalls just to our south and lifts north again later on Friday into Saturday it would be the focus for ongoing development during this period. Specifics are too uncertain to pin down at this range, though it does appear the position of this boundary will be one of the keys to monitor for the weekend. Until things are more clear, plan to carry chances of precip both Friday and Saturday, with the late weekend drier for now. MDB && .AVIATION... For the 00Z TAFs... 707 PM...Forecast concerns include... Scattered showers this evening. Mvfr cigs through Tuesday morning. Possible ifr cigs/fog overnight. Gusty westerly winds Tuesday. Scattered showers will continue across the terminals this evening with briefly lower vis into mvfr. Not expecting any thunder with this activity. Any additional showers or isolated thunderstorms later tonight are expected to remain well south of the terminals. There may also be a few showers Tuesday afternoon but expected coverage will be isolated. Cigs have remained generally vfr with some patchy mvfr through late afternoon but are expected to trend into mvfr this evening and lower to low mvfr overnight with ifr possible. But confidence for ifr cigs is low and have only included scattered mention for ord/mdw. Cigs will lift through mvfr Tuesday morning with a low vfr deck expected Tuesday. West/southwest winds 10-15kts with higher gusts will continue this evening and slowly diminish overnight. Winds will turn more west/ northwest Tuesday morning with speeds increasing and gusts to 20kts possible for the afternoon. cms && .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 Memphis TN
918 PM CDT Mon Aug 26 2019 .UPDATE... A lull in convection is occurring the Mid-South at this time. Some clearing has occurred over portions of the area which may lead to some fog development. After midnight, convection that is currently occurring along the I-44 corridor in Missouri will begin to push into Northeast Arkansas. The convection may be moving into the Memphis Metro area around sunrise. Have adjusted POPS for the overnight into the morning and added mention of fog. Rest of forecast looks good. KRM && .DISCUSSION... /issued 344 PM CDT Mon Aug 26 2019/ An unseasonably deep upper low will lift from southern Manitoba to northern Quebec this week. This feature will remain sufficiently broad to result in northwest aloft across the Midsouth, which will aid in a surface cold frontal passage late tonight. No significant cooldown associated with this front, but drier air (dewpoints in the upper 50s to mid 60s) will begin spreading into the Midsouth late Tuesday, and persist into late week. The drier air will allow for overnight lows to cool as the low as the upper 50s in the valleys near the TN River. In the interim, short term convective trends remain the primary forecast challenge. Midafternoon regional radar mosaic showed a semi- linear cluster of storms dropping into southern MO, well ahead of the short term convection-allowing model (CAM) guidance. The 19Z HRRR model finally initialized the position of the MCS, but depicted the storms dissipating over southeast MO by 00Z/7PM CDT. SPC Mesoanalysis showed less instability and weaker shear toward the MO bootheel at 20Z, but no so much as to preclude thunderstorms. Reality may lie somewhere in between, with loss of surface heating resulting in stronger capping and storm dissipation over northeast AR toward midevening. Afternoon forecast package relies less on short term CAM guidance and more on extrapolated convective trends. For the overnight, attention remains on eastern KS for early evening convective-initiation. This area is where CAM consensus generates an additional MCS, fed by a post-sunset 35kt low level jet. Resultant storms would move southeast into AR and perhaps west TN through sunrise. This secondary MCS would have a synoptic cold front on which to focus convection initially. This front had just exited the southeast corner of Nebraska at 3PM CDT today. The front will likely slow over north MS Tuesday, where dewpoint pooling and surface heating will provide a chance of storms. Thereafter, an extended dry period is forecast through Saturday. An upper level ridge building in from the southern plains will bring warmer and predominately dry weather to the Midsouth on Labor day, toward the middle of next week. PWB && .AVIATION... 00Z TAfs Confidence growing that convection in southern Missouri will weaken over the next couple of hours while a new line develops farther back along an approaching cold front. This new line will affect the sites later in the period so timing of convection has been adjusted. VFR to start but conditions will drop to MVFR and IFR. Before convection fog may form at MKL and TUP with possible LIFR. Showers taper off late with VFR cigs. Light south winds veering westerly late. Higher gusts near T-storms. JAB && && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
939 PM CDT Mon Aug 26 2019 .DISCUSSION...See updated information for land areas below. && .UPDATE...Current forcast has been updated to reflect current downtrend in precipitation coverage over the forecast area. Latest guidance still advertising an increase in rain coverage after 06Z as a piece of shortwave energy moves through an upper trough stretching ssw across the region. With limited instability, have cut back on the rumbles in the weather from previous forecast. Temperatures are on track, so no adjustments needed there. Updates out shortly. /16 && .PREV DISCUSSION... /issued 644 PM CDT Mon Aug 26 2019/ DISCUSSION...Updated for latest aviation discussion below. AVIATION... 00Z issuance...General mid-MVFR and VFR conditions were observed across the forecast area at 23z, with rain covering most of the area. Local drops to IFR or lower in the heavier rain over areas east of the Alabama River were also noted. As the forecast progresses into the evening, rain coverage will continue to decrease in strength and coverage, though abundant mid/upper level cloud will help to limit fog formation and low end MVFR or lower VISBYs through the overnight hours. Southerly winds of 5 to 10 knots are expected to last through the night. Tuesday, showers are expected to develop close to sunrise, and become thunderstorms late morning into the afternoon. MVFR conditions are expected to start the day, becoming general VFR, with local MVFR in the convection. Southerly winds around 10 knots are expected during the day. /16 PREV DISCUSSION... /issued 400 PM CDT Mon Aug 26 2019/ NEAR TERM /Now Through Tuesday/...Upper-level energy and the deep plume of tropical moisture previously located off the SW Louisiana coast has triggered widespread convection as it moved over the area today. Convection is expected to gradually diminish in the evening to late night hours as the airmass stabilizes and the main forcing for ascent eventually shifts east. The HRRR projects the last robust band of convection now moving eastward into SW MS to move eastward through SE MS by early evening and across S AL and NW Florida during the evening to a little after midnight. Weak troughing aloft remains over the area tomorrow with elevated PWATS of 2 to 2.25". Expect scattered to numerous showers and thunderstorms to again develop with surface heating and low level lift courtesy of the lingering outflow boundaries generated by today`s convection. Breaks in cloud cover tomorrow should allow daytime temperatures to climb into the upper 80s to lower 90s. /08 SHORT TERM /Tuesday night Through Thursday night/...As stability increases during the evening hours convection will decrease with only a slight chance of thunderstorms expected across most of the area. A chance will remain along the coast as storms are expected to continue to form over the warm Gulf waters overnight and potentially move over coastal areas before dissipating. A cold front approaches from the northwest and pushes southward across the area Wednesday and moves out over the Gulf Wednesday night. Scattered to numerous showers and thunderstorms develop during the day along and ahead of this boundary shifting south over the marine area during the evening hours. A drier, northerly flow will follow in the wake of this system. Cooler overnight lows anticipated Wednesday night, falling into the mid 60s to near 70 over northern inland locations and low to mid 70s closer to the coast. A drier airmass settles over the area through Thursday night and subsidence from the low and mid-level ridge over the region should suppress the development of convection. The lack of showers and sunny skies will allow temperatures Thursday afternoon to climb to around 90 and possibly into the mid 90s. Fair skies and drier air Thursday night will lead to relatively cool overnight lows...low to mid 60s inland to upper 60s low 70s closer to the coast and mid 70s along the immediate coast. /08 LONG TERM /Friday Through Monday/...A moist low level return flow starts to develop late Friday as surface high pressure to the north shifts eastward into the western Atlantic. By Saturday deep layer moisture starts to pool over the region as onshore flow increases and the region lies in between the ridge aloft to the east and west. Diurnally driven afternoon convection is expected to begin Saturday and continue into Monday. Temperatures are forecast to trend near to a little warmer than climatological norms. In the tropics, Tropical Storm Dorian is forecast by the National Hurricane Center (NHC) to impact the Lesser Antilles tonight and tomorrow and then follow a northwestward track and move in the vicinity of the Bahamas by this weekend. There still remains a great deal uncertainty and inconsistencies among the models on how this system will evolve and the track it will take through the week. We will continue to monitor the evolution of Dorian closely and provide updates as needed. /08 MARINE...A light to moderate onshore flow will continue through Tuesday night with an offshore flow developing Wednesday and becoming easterly by this weekend. Periods of scattered to numerous thunderstorm activity are expected through Wednesday. A weak cold front will approach from the north and move southward across the Gulf Wednesday night. Shower and thunderstorm activity will decrease following its passage but will return to the marine area this weekend. /08 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...None. FL...None. MS...None. GM...None. && $$ This product is also available on the web at:
Area Forecast Discussion
National Weather Service Paducah KY
1100 PM CDT Mon Aug 26 2019 .UPDATE... Issued at 1100 PM CDT Mon Aug 26 2019 Updated aviation discussion. && UPDATE... Issued at 921 PM CDT Mon Aug 26 2019 The next round of convection is already firing up over central Missouri. The latest HRRR output is too slow and likely too intense, but the 00Z WRF runs seem reasonable for the more organized convection just after 06Z. Figure the thunder will be focused over southeast Missouri, with the best chance of severe winds running along the southwest edge of this afternoon`s storms. Still expecting a weakening, if not dissipating, trend as it moves farther east into the area. The Ft Campbell area may not get wet at all. && .SHORT TERM...(Tonight through Tuesday night) Issued at 237 PM CDT Mon Aug 26 2019 MCS over south central MO moving ESE at 45 mph. None of the models handled this activity at all. So needless to say our PoPs are geared toward reality. The area should enter southeast MO from 4 to 430 PM. How far east it makes it is very much in question. Given mesoscale trends, would not be surprised if it continues into southern IL and west KY for finally winding down a bit. There is a chance of severe thunderstorms mainly over southeast MO. The airmass is unstable and the activity is being supported by a 40-50kt mid level wind max. After this activity is no longer a factor, the convective allowing models continue to show more activity later tonight with the front, with chances continuing into Tuesday morning, ending in the afternoon across the KY Pennyrile region. Temps will be a blend of existing numbers and the latest NBM output. .LONG TERM...(Wednesday through Monday) Issued at 237 PM CDT Mon Aug 26 2019 Although not depicted properly early on by the NBM (National Blend of Model) guidance, the NBM has finally settled on a dry solution for the latter half of the week and into the weekend for the WFO PAH forecast area. Most of the numerical model suite keeps the local forecast area of the influence of High Pressure through Friday, with another surge of high pressure building into the area over the weekend. The lack of deep layer moisture across the area, combined with a flattening of the eastern Canada/Hudson Bay trough, will definitely keep the WFO PAH forecast area dry through Friday. The preferred CMCnh (Canadian) guidance does sharpen the trough over the Middle Mississippi Valley Saturday night into Sunday, but moisture is lacking over the area during this time, so the potential for measurable PoPs is quite limited. Hesitated to drop PoPs for Saturday, given the small potential entered in previous forecasts. However, given the limited PoP potential to begin with, opted to keep a dry forecast in place with this forecast package. Will be interesting to see if T.S. Dorian has any impact beyond this forecast period per medium range model guidance solutions. Will monitor official NHC forecasts for trends. && .AVIATION... Issued at 1100 PM CDT Mon Aug 26 2019 Overnight, winds are forecast to return to southerly at less than 12 knots sustained, as more shower and tstm activity associated with a cold front moves in from the west. Toward daybreak and into Tue morning, MVFR cigs are likely across the region, with some flirtations with IFR. Under stronger showers/tstms, brief IFR vsbys are possible, otherwise vsbys should be VFR most of the time. Winds are expected to begin a turn to the northwest after daybreak Tue, with the wind shift progressing northwest to southeast. Scattered shower and tstm activity will diminish and sky conditions will improve with the wind shift during the day Tue. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ UPDATE...DRS AVIATION...DB
Area Forecast Discussion
National Weather Service Topeka KS
808 PM CDT Mon Aug 26 2019 .UPDATE... Issued at 800 PM CDT Mon Aug 26 2019 With the H850 trough having passed through the area, the threat for thunderstorms has shifted south and east of the forecast area. Have removed mention of storms from the grids and products. Fog threat seems very limited in scope and coverage given the 2-4 mb pressure difference across the forecast area through the overnight hours and ongoing negative theta-e advection. Winds at the top of the very shallow BL inversion should remain in the 10 to 15 kt range, which should help keep the airmass mixed enough to hinder fog formation. && .SHORT TERM...(This evening through Tuesday) Issued at 332 PM CDT Mon Aug 26 2019 A surface cold front is moving eastward across the forecast area this afternoon. As of 20Z, the front was located from around Hiawatha to just east of Manhattan to near Council Grove. Thunderstorms will likely develop along the front, but there remains some uncertainty as to exactly where and when storms will initiate. This morning`s convection left an area of cloud cover over the region and expected instability has not been realized so far today. The HRRR now confines the best surface based instability to areas along and southeast of I-35, where the model shows over 3000 J/Kg of CAPE with no inhibition at 21/22Z ahead of the front. The RAP has also started to trend southward with the best dynamics for thunderstorms, which makes sense given the location of the outflow from earlier activity. As such, it looks like the most likely area for thunderstorm activity this afternoon will be along and south of I-35. The front will clear the area by around 00/01Z, taking storms with it. A few gusty winds will be possible just behind the front with a tight pressure gradient in place. Surface ridging will commence following fropa, and winds will quickly relax by this evening. Drier air will move in tonight with dewpoints dropping into the upper 50s north of I-70 by sunrise Tuesday. With light winds, clearing skies and dewpoint depressions of only a few degrees, patchy fog will be possible by early tomorrow morning, especially in areas that received rainfall this morning and areas that receive rainfall this afternoon. Higher pressure will continue to work into the area tomorrow with the center of the surface high located directly over central KS by Tuesday night. Temperatures will only warm to near 80 degrees under sunny skies, making for very enjoyable conditions tomorrow afternoon. .LONG TERM...(Tuesday night through Monday) Issued at 332 PM CDT Mon Aug 26 2019 High pressure will stay in control of our conditions through midweek before it begins to move southeast of the region on Thursday. Southerly winds on the back side of the surface ridge will begin to advect moister and warmer conditions into the CWA on Thursday. The next chance for rain and storms appears to be late Thursday or early Friday when the next front is forecast to move into northeastern portions of Kansas. A more active pattern could persist into early next weekend so will monitor those trends through the week. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 640 PM CDT Mon Aug 26 2019 MVFR stratus clears from northwest to southeast this evening, with no restrictions expected tonight or on Tuesday. Winds will be from the north to northwest at 5 to 10 kts. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Skow SHORT TERM...Teefey LONG TERM...Teefey AVIATION...Skow