Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/20/21

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
915 PM CDT Sat Jun 19 2021 .UPDATE... Issued at 850 PM CDT Sat Jun 19 2021 One or two showers/thunderstorms have popped up over the CWA in the last few hours, mainly along a boundary across the far northern CWA. Meanwhile, the most significant thunderstorms remain across western South Dakota, in an atmosphere with around 1000 j/kg of ML CAPE and 45+ kts of effective shear. Much less favorable environment over our CWA. Progs are barely squeaking out 500 J/KG of most unstable CAPE over our area. So severe threat remains low. Regardless, still expecting to see an increasing low level jet and better forcing as the upper level trough approaches. So it is logical to expect shower and thunderstorm activity to increase in areal coverage overnight. Made some slight adjustments to the POP forecast, but overall seems to be capturing the general trends well. UPDATE Issued at 638 PM CDT Sat Jun 19 2021 See the updated aviation discussion below. && .SHORT TERM...(This Evening through Sunday Night) Issued at 244 PM CDT Sat Jun 19 2021 A surface high pressure is producing mild temperatures and low dew points across the CWA this afternoon. There is some weak moisture return ongoing over southwest SD where dew points are climbing into the upper 40s and 50s. Better instability is noted over western Nebraska where a mid level shortwave is producing convection. Various CAMS suggest this convection will track eastward tonight, or well south of the CWA. Another shortwave embedded within northwesterly flow aloft should bring showers and thunderstorms into this CWA later this evening and into the morning hours on Sunday. Weak convection over eastern MT, western ND around 0Z should track east-southeast overnight with the northeastern portion of the CWA having the best potential for pcpn, mainly after 6Z. Based on consistency with the past few hours of the HRRR and RAP, have lowered pops over the southeastern CWA throughout tonight, but have maintained higher pops over the northeast CWA. Low clouds and cooler temperatures can be expected behind the storm system on Sunday. With a cloudy sky, isolated to scattered storms, have lowered highs a few degrees, or closer to the 25th percentile of the NBM. Winds will be gusty from the north with gusts of 30 to 35 mph possible. .LONG TERM...(Monday through Saturday) Issued at 244 PM CDT Sat Jun 19 2021 A somewhat amplified upper trof will exist over the eastern CONUS early in the period. However, the amplitude of the pattern will gradually modify through the period, such that the below normal temperatures early in the week are expected to rebound somewhat by mid to late week. At that time a mid-level thermal ridge will again expand across the Northern Plains, with a consequent increase in surface temps, likely going back above normal. Another bit of energy may dive into the Northern Plains late in the week, with another cooldown expected. Temperatures, like mentioned before, will start the period below average, but then should soar back above by mid- week. && .AVIATION...(For the 00Z TAFS through 00Z Sunday Evening) Issued at 638 PM CDT Sat Jun 19 2021 Terminals KABR,KATY,KPIR,KMBG Starting to see isolated convection develop along the WY/SD border this evening. Short term model guidance suggest this activity will remain scattered and continue to track east, reaching the KMBG/KPIR TAF sites around the 04Z-06Z time frame, and the KABR/KATY sites after 06Z. Any thunderstorms could produce MVFR conditions. Could see MVFR CIGS hang across the region into Sunday morning across eastern South Dakota. Meanwhile frontal boundary will switch winds from the south to northwest through the day Sunday. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Serr SHORT TERM...SD LONG TERM...TDK AVIATION...Serr
Area Forecast Discussion
National Weather Service Burlington VT
1013 PM EDT Sat Jun 19 2021 .SYNOPSIS... Isolated to scattered showers and storms will come to an end this evening across the North Country. Dry weather is then expected overnight and Sunday as a weak area of high pressure builds into the region. Highs on Sunday will be a few degrees above seasonal normals, but well above normal on Monday with highs in the 80s to around 90. Monday afternoon and evening will see the threat of showers and thunderstorms increase with some of the storms potentially being strong to severe. && .NEAR TERM /THROUGH SUNDAY NIGHT/... As of 1013 PM EDT Saturday...Minor late evening update made to the forecast to adjust for cloud cover and PoPs for the next few hours. Mid/high clouds pushed a little farther north than previously anticipated, but should recede to the south after midnight as expected. In addition, an isolated shower recently popped up over Lake Placid and based on the 00Z HRRR there is the possibility of a couple more isolated showers from the high peaks of Essex County NY eastward through central VT through midnight. Rest of the forecast remains on track. Previous Discussion...Afternoon convection has died off and all indications continue to point toward ongoing convection south of the forecast area remaining south. Hence, a quiet night is on tap for the North Country with mid/high clouds across central/southern areas clearing out towards midnight. With many areas receiving rainfall either early this morning or this afternoon, we`ll likely see areas of fog develop after midnight under clear skies and light winds. This should mainly be in the favored locations across the Adirondacks and central/northern VT but honestly can`t rule it out anywhere. Temps remain on track to fall into the 50s for most locations, except locally closer to 60 around Lake Champlain. Weak high pressure will be over the area Sunday and Sunday night for a continuation of the dry weather. Highs on Sunday will be in the upper 70s to mid 80s and with developing south to southwest flow Sunday night lows will generally be in the upper 50s to mid 60s. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... As of 356 PM EDT Saturday...Composite analysis continues to show the potential for strong to severe storms Monday afternoon and evening. Thermal axis at 850 millibars extends up across our area with highs getting into the mid 80s to lower 90s. Dew points will also be in the 60s and this should allow for instability to develop in the afternoon. Looking at CAPE values of at least 1500 J/kg ahead of a pre-frontal trough moving into the Saint Lawrence Valley of New York late in the day. Deep layer shear will be increasing over the area as well although the strongest shear lags to the west of the instability axis. Nevertheless there will still be some favorable alignment of instability and shear ahead of the boundary to enhance the potential for thunderstorms, some of which could be strong to severe. Feel portions of northern New York and portions of western Vermont will have the best potential for this greater storm threat, which pretty much lines up with the slight risk that the Storm Prediction Center has for Monday. Eventually the pre-frontal trough and a more defined cold front will move into the area Monday night and showers and isolated storms should be rather widespread across the entire area. Higher axis of precipitable water values will lead to some higher precipitation amounts with values in the half inch to inch range Monday and Monday night. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 356 PM EDT Saturday...A continuation of light rain will be seen through the first half of Tuesday before the upper level trough axis swings through and high pressure quickly builds back across the region. In previous model runs, there was a lot of disagreement amongst the global models on whether or not we would see a period of drier weather across the region with the GFS being the outlier. With the 12Z model package, all models are in good agreement that we will see a period of dry weather extending from Tuesday afternoon and continue through at least Friday. The next storm system appears to be on the horizon sometime next weekend with yet another amplified upper level trough approaching the region. This should bring another nice swath of rainfall to the North Country but exactly when next weekend remains up in the air for now. In the meantime, enjoy the nice seasonal airmass that will bring highs in the mid 70s to mid 80s and lows in the lower 50s to lower 60s through much of next week. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Through 00Z Monday...Aviation challenge tonight will be fog/br potential at SLK/EFK and MSS, after receiving rainfall in the past 12 to 24 hours. Crnt satl shows mid/upper lvl clouds advancing into our region, while northerly sfc winds help to pull drier air southward into our taf sites. Expect mainly clear skies to develop by 03z with light winds. This should allow for temps to reach cross over values with patchy fog developing, especially SLK and EFK. Have utilized tempo group to highlight ifr potential in fog/br at both sites with mvfr possible at pbg/mss btwn 06-11z. Expecting conditions to bounce up and down btwn vfr and mvfr/ifr at mss/pbg, with vfr elsewhere. VFR with light southerly winds develop on Sunday with a few cumulus clouds developing over the trrn toward 18z. Outlook... Sunday Night: VFR. NO SIG WX. Monday: VFR. Chance SHRA, Chance TSRA. Monday Night: Mainly VFR, with local MVFR possible. Likely SHRA, Slight chance TSRA. Tuesday: Mainly VFR, with areas MVFR possible. Likely SHRA. Tuesday Night: VFR. Chance SHRA. Wednesday: VFR. NO SIG WX. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Evenson NEAR TERM...Evenson/Lahiff SHORT TERM...Evenson LONG TERM...Clay AVIATION...Taber
Area Forecast Discussion
National Weather Service Dodge City KS
1059 PM CDT Sat Jun 19 2021 ...Resent aviation... .MESOSCALE DISCUSSION... Issued at 1040 PM CDT Sat Jun 19 2021 An MCS continues to track east across central and southwest Kansas through mid evening. This cluster of storms has produced strong to severe outflow winds across Ellis and Trego counties with severe wind gusts along I-70 in the Hays area over the past hour. Farther south, outflow winds were pushing southeast ahead of an area of weakening thunderstorms and stratiform rain. For the most part, winds behind this gust front should be sub severe with gusts to 40-50 mph, although isolated severe wind gusts could still occur immediately behind the gust front through midnight. .SHORT TERM...(This evening through Sunday) Issued at 319 PM CDT Sat Jun 19 2021 A stationary front that was straddled southwest-east across our area this morning is looking a little more like a warm front this afternoon as expanding mid and high clouds have generally cut the temperates several degrees off the kind of heat we saw yesterday at this time. There is a strong gradient of CAPE across that boundary going northward as the available moisture in the layer is much higher noted by PWATS in excess of an inch and impressive MCS maintenance parameter values north of DDC, as well a extending sw into the Elkhart sfc low area. The HRRR has been showing hour to h our variations of cold pool generated linear convection developing out of eastern Colorado and northwest Kansas entering our west central Kansas counties perhaps by around 830PM CDT / 730PM MDT with best risk potential for 60 to 70 mph wind gusts while weakening along the southern half but having he best chance to maintain and cold pool/updraft convergence zone balance along the I-70 corridor though around 11pm. On Sunday, Thunderstorms may develop along a stalled sfc boundary in the late afternoon with sufficient surface differential heating along the front to trigger updrafts development. If this occurs, the best area will be from around Pratt county to Clark State lake area and quickly moving eastward. Not all of the convective allowing models are onboard with this, however as the most robust organized development is pronounced in all the CAM over far eastern Kansas along the said front. Additionally, leftover outflow boundaries from the previous night`s convection may muddy the waters on certainty with respect to this. .LONG TERM...(Sunday night through Saturday) Issued at 319 PM CDT Sat Jun 19 2021 Sunday night, the northern and central high plains will be in an axis of a sharply amplified upper trough that will quickly transition into northwest upper flow by Monday, placing our area under northwest flow aloft. Additionally, reinforcing, cooler drier high surface pressure airmass will be moving equatorward into the Mississippi valley and central Plains. A combination of forcing for ascent due to the northwest flow jet in a weakly unstable mid level airmass with enough shear present to propagate a few rotating storms across the area Sunday night, and into early Monday morning, possibly resulting in a few marginally severe or more likely...mainly sub severe elevated hail storms. This will lead to much cooler temperatures on Monday owing to both cold advection and leftover moisture from the clouds and precipitation itself. Monday has been dramatically cut to the mid 70s for afternoon highs. The reprieve is very short lived however as the next plume of downslope high terrain air descend onto the central Plains, ramping temperatures likely back into the low 100s on a widespread basis by Wednesday. Dryline convection may become an issue to figure out by Wednesday and Thursday afternoon in out easternmost counties judging by the signals from the global spectral models. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) Issued at 1111 PM CDT Sat Jun 19 2021 Showers and thunderstorms will continue to march across the terminals through midnight. The worst severe storms have begun to spread east of KHYS now. Any strong outflow winds should weaken considerably in the short term period. Otherwise, winds will become N/NE later today in the wake of a fropa. VFR conditions are expected. && .PRELIMINARY POINT TEMPS/POPS... DDC 72 101 61 77 / 40 0 50 20 GCK 67 97 59 76 / 50 0 50 20 EHA 66 99 59 76 / 30 0 30 10 LBL 70 101 61 77 / 30 0 30 10 HYS 69 95 60 77 / 70 0 60 30 P28 76 104 65 79 / 10 10 40 30 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOCALE...Gerard SHORT TERM...Russell LONG TERM...Russell AVIATION...Sugden
Area Forecast Discussion
National Weather Service Goodland KS
542 PM MDT Sat Jun 19 2021 .SHORT TERM...(This evening through Sunday) Issued at 340 PM MDT Sat Jun 19 2021 There is potential for severe storms this afternoon and evening. As of 3 PM MDT, storms are beginning to develop along and east of I-25. These storms are mostly isolated to scattered in nature; however, as they move east the storms will develop into more of a line. These storms are being driven by shortwaves moving southeast across the Rockies ahead of an approaching cold front on Sunday. The HRRR is handling the event fairly well, especially with the storm mode evolution. MLCAPE values are in the 1000-2000 j/kg range with a veering wind profile. Shear profiles are favorable with 30-40 kts of EBWD and 30-50 kts of 0-6 km shear oriented to the W/WNW. Mid-level lapse rates are range from 8-8.5 C/km across the area, indicating a favorable environment as the storms move across. The main threat this afternoon/evening is damaging winds up to 75 mph and 1-2" hail. The hail threat is expected to diminish while the wind threat increases as the storms move across NW KS and SW NE. With the recent dry conditions, there is potential for blowing dust and reduced visibilities due to strong outflows from the storms. A brief tornado can`t be ruled out; however, confidence is fairly low. Locally heavy rainfall is possible, especially along the KS/NE border. Given the storm motion and recent dry conditions, I`m not expecting flash flooding to be much of an issue. The storms are expected to exit the area around midnight. Overnight lows are expected to be in the upper 50s to upper 60s tonight with winds shifting to the SW then W behind the line of storms at 10-15 mph. Sunday, a cold front is expected to move southeast across the area during the morning to early afternoon. As this front moves through, winds are expected to increase to 15-25 mph as they shift to the north. A few weak disturbances are expected to move across the High Plains behind the front, which will boost precipitation chances for the late afternoon and evening hours. Thunderstorms are possible; however, the severe threat is fairly low. Showers and storms are expected to impact the area through the overnight hours. Temperatures will be slightly cooler tomorrow, thanks to the cold front, with highs in the 80s to lower 90s and lows in the 50s. .LONG TERM...(Monday through Saturday) Issued at 335 PM MDT Sat Jun 19 2021 NW flow aloft will prevail at the beginning of the long term period.. on the eastern periphery of an upper level ridge over the Rockies and Intermountain West. Flow aloft will back to the west by mid-week as the ridge shifts ESE to the Southern Plains. Split flow aloft is anticipated over the western CONUS by the end of the week.. as an upper level low stalls invof the central Pacific Coast. Expect increasing temperatures Tue-Wed.. as heights rise in assoc/w the ridge progressing from the Rockies to the Southern Plains. Temperatures will level off or slightly cool by late week. At this time, precipitation chances appear very low.. though uncertainty increases considerably by late week into the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 542 PM MDT Sat Jun 19 2021 Vfr conditions are initially forecast at both KGLD and KMCK terminals at the start of the TAF period. The main impact this evening will be a line of thunderstorms pushing through the region from west to east. Timing may need to be adjusted, but current thinking is storms will make it to KGLD around 02z and KMCK around 03z, bringing a brief period of very strong winds and reduced visibilities due to rainfall. Beyond this, conditions will improve overnight, with decreasing clouds as well as light and variable winds. A cold front brings gusty north winds to both sites by mid morning Sunday. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...KMK LONG TERM...VINCENT AVIATION...JBH
Area Forecast Discussion
National Weather Service Grand Rapids MI
1107 PM EDT Sat Jun 19 2021 LATEST UPDATE... Update .SYNOPSIS... Issued at 318 PM EDT Sat Jun 19 2021 - Convection moves out and skies clear tonight - Threat of severe storms and flooding rain Sunday night - Cooler midweek than warming once again with storms returning && .UPDATE... Issued at 1107 PM EDT Sat Jun 19 2021 We will be keeping an eye on fog potential tonight which is obviously quite good given rains from last night into this morning, partially clear skies and light winds. All areas have the potential for fog tonight. Local guidance for ceilings and visibilities show locations to the south of a line from Holland to Alma most primed for more substantial fog. Not out of the question to see some dense fog tonight, especially along the I-94 corridor. At this point not issuing a Dense Fog Advisory, but we will be monitoring trends. Showers and a few storms continue to percolate across our southern CWA, but we expect this trend to continue to be down as we lose daytime heating. && .DISCUSSION...(This evening through next Saturday) Issued at 318 PM EDT Sat Jun 19 2021 - Convection moves out and skies clear tonight The last of the convection from this morning is currently exiting the area as the mid-level shortwave, that created it, is now moving east, out of the area. Water vapor image loops show a considerable amount of dry air following this system. That, in combination with shortwave ridging, will allow for clearing skies by this evening. With light winds and mostly clear skies, plus all the rain that fell near and south of I-96 this morning ( over 3 inches in places), some areas of fog are more than possible toward morning. Any fog that does develop will quickly mix out by mid morning Sunday. Father`s day, will for the most part of the day, features some sunshine with pleasant temperatures for this time of year. That sunshine in the morning is the result of the upper level ridging, that will be building over the Great Lakes, in response to the digging polar jet core over Montana in the morning. - Threat of severe storms and flooding rain Sunday night The threat for strong to severe thunderstorms with locally heavy rain and even a risk of isolate tornadoes moves into this area late Sunday afternoon. This is the result of that same digging polar jet that comes in phase with a digging northern stream jet core. The result of this is an unusually strong surface system for this time of year. The jet core tracks through northwest Lower Michigan Sunday night. That puts southwest Michigan classic position for strong to severe storms. The triple point of the system will track near I-94 during the mid evening hours. Given the upper jet is over Lake Michigan, this results in strong deep layered shear. The southerly winds ahead of the system bring in deep Gulf of Mexico moisture. The means deep, moist lift, with a fair amount of shear over our area. The treat for strong to severe storms will be highest south of I-96 during the evening. As is typically the case, the warm front being where it is, enhances the risk for tornadoes during the evening (near I-94). With all that deep lift and precipitable water values rising to over 1 1/2 inches there is the threat of heavy rainfall. Since the front will be nearly stalled near I-94, it is more than possible the storms will train over the same area for a good part of the night. The HRRR is showing widespread rainfall over 2 inches near I-94 tomorrow night. Given recent rainfall in this area, this may result in some flooding. We will have to watch this closely. Monday morning the cold front comes through and that Will likely have convection associated with it too. Given the strong dynamics of this system strong thunderstorms will remain possible into mid morning Monday. - Cooler midweek than warming once again with storms returning As the system moves through the area Sunday night moves out, a deep eastern trough develops. By Tuesday the polar jet even gets south of this area. This will give us a few days of colder than normal temperatures. There is yet another strongly digging northern stream system will cause another brief building of an eastern upper ridge. That starts on Wednesday. This may lead to some warm air return convection possible on Wednesday. Late in the week another storm system will bring the threat of heavy rain and strong to severe thunderstorms. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 807 PM EDT Sat Jun 19 2021 Some areas of MVFR ceilings are occurring across Southwest Lower Michigan at 00z. This is not expected to become widespread and should lift/scatter out this evening. Overnight however, fog is expected to fill in with at least MVFR conditions at most TAF sites. This should mainly be a visibility issue, but the exception to that is from KAZO to KBTL and KJXN where IFR ceilings will most likely fill in. We may need to hit the IFR ceilings harder at the I-94 TAF sites for the overnight into Sunday morning. The fog and stratus should lift fairly quickly by 15z on Sunday. The next focus is on a strong to severe thunderstorm evening across Southern Lower Michigan Sunday afternoon and evening. Thunderstorms will be sweeping across the TAF sites in the late afternoon and early evening likely between 500pm and 900pm. Timing is still a bit uncertain though and we have held the thunder off for the time being in this set of TAFs at KLAN and KJXN. The potential exists for all hazards in regard to severe weather including strong and damaging winds in excess of 40 knots after 21z on Sunday. && .MARINE... Issued at 318 PM EDT Sat Jun 19 2021 The biggest marine weather issue will be when the cold air comes back on Monday we may need to issue a small craft advisory. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...Duke SYNOPSIS...WDM DISCUSSION...WDM AVIATION...Duke MARINE...WDM
Area Forecast Discussion
National Weather Service Gray ME
1057 PM EDT Sat Jun 19 2021 .SYNOPSIS... A front will move through this evening bringing showers and thunderstorms to the region. High pressure makes a brief appearance tomorrow into Monday but with the caveat of building heat and humidity. Precipitation chances return late Monday through Tuesday night as a frontal complex crosses New England, perhaps picking up some tropical moisture as it does so. High pressure then returns for a cooler and quiet end to the week. && .NEAR TERM /TONIGHT/... 11PM UPDATE... Rather large area of rain across southern New England continues to miss us to the south. However, an area of rain positioned a bit farther north just east of Lake Ontario now stands a better chance of making it into southern NH by around 2AM. Have updated precipitation chances to increase the chances of rain in southern NH to account for this. Otherwise no significant changes to the forecast. 830PM UPDATE... Cold front has made its way to the coast of Maine and the shower and thunderstorm threat has ended. Forecast update was primarily to update the wording in products from earlier thunderstorms as well as make small adjustments to temperature trend tonight. 345PM UPDATE... Made some adjustments to precipitation chances over the next few hours based on current thinking. Low level moisture has lingered roughly from I-95 eastward while dry air has moved in aloft. This has led to greater instability in this area, and more intense thunderstorms. Behind this line, the dry air is mixing down along with warm temperatures. Still a few showers and stray storms in this area, although updrafts will not be as intense here. The drier low level environment, though, will make strong winds possible here as well, though. Should see the stronger activity move offshore and into eastern Maine within the next 2 hours. ORIGINAL DISCUSSION... Cold front and pre-frontal trough crossing the area will bring scattered thunderstorms through this evening. Latest RAP analysis brings an area of effective shear in excess of 35 kts across the area with pockets of effective shear to 55 kts over south-central Maine. This shear will overlap an axis of SBCAPE to 1500 J/kg from interior York County into the White Mountains and then eastward through the Mid- Coast of Maine. It is here where thunderstorms will have the greatest chance to become severe with damaging winds and marginally severe hail through 7 pm this evening. Across the southern half of New Hampshire dry air aloft has mixed to the surface causing dewpoints to drop into the low 50s limiting the chance for thunderstorms south of the White Mountains. The threat for severe storms will diminish after 7 pm with lingering showers and thunder across eastern zones through the first part of tonight. The cold front decelerates tonight and does not clear the area until tomorrow morning. Overnight some convective debris from thunderstorm activity over PA and western NY this afternoon will track across southern New England. This debris will bring increasing clouds tonight across southern New Hampshire with a slight chance for showers. Lingering low level moisture will lead to patchy fog near the Mid-Coast and in northern valleys. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... Cold front will be pushing through southern New England Sunday morning. The cooler air behind the front does not make it into the forecast area and with H8 temps rising to +15C to +16C leading similar high temperatures as today with dewpoints in the 50s. Small surface high crosses the area Sunday afternoon for mostly sunny skies. High pressure shifts offshore Sunday night with higher dewpoint air being advected into the area by Monday morning. This will lead to areas of patchy fog to develop by morning along the coast and in valley locations. && .LONG TERM /MONDAY THROUGH SATURDAY/... No significant changes to the going forecast at this time as latest deterministic and ensemble guidance have not shown any major shifts in mass fields. On Monday a long wave trough will continue to amplify across the midwest/south with heat and humidity increasing on the East Coast in the deep southerly/southwesterly flow ahead of the trough. Heights will gradually fall on Monday as the trough approaches and these will be associated with a SFC cold front. The question thus far has been how fast does the cold front progress during the day on Monday? Most guidance has remained fairly slow, allowing for a dry or mostly dry and hot day on Monday. However, a few pieces of guidance are a little more progressive and give the western zones a shot at strong thunderstorms late in the day. PWATS will be high in any event, so we`ll have to watch for localized flooding if thunderstorms do make it into our region during the day. Other slower solutions have a more widespread convective fropa on Tuesday with some additional tropical moisture infused thanks to what should be the distant remnants of Claudette. As far as our forecast PoPs go Mon/Tue, have hedged a bit toward the slower solution. We`ll cool down for a day or so in the wake of the cold front around Wednesday, but then it appears that we get right back into a summery pattern. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... Short Term...Mainly VFR through Sunday, but could see temp restrictions due SHRA/TSRA this evening at KHIE and KAUG. There is a chance for some patchy fog along the Mid-Coast and in the Connecticut Valley early tomorrow morning, but confidence is not high enough to put in the TAF. There is abetter chance for low cigs and fog Sunday night as low level moisture returns from the south. Long Term...Low cigs/vsbys possible on the coastal plain Monday morning before lifting. Otherwise, there will be a chance of thunderstorms Monday evening across western NH. We expect for low clouds and perhaps fog to move back in Monday night into early Tuesday morning on the coast with moist southerly winds expected. Tuesday may feature more widespread showers and thunderstorms, but confidence on that is low at this time. A return to widespread VFR conditions is likely Tuesday night and Wednesday. && .MARINE... Short Term...S-SW flow will gust 20 to 25 kts this evening ahead of a cold front and will subside early tonight. Seas will run to 5 ft along the outer waters through the first part of the night. Weak high pressure crosses the waters Sunday for quiet conditions. Long Term...SCA conditions are likely, at least outside of the bays, Monday and Monday night as southerly flow increases and brings seas up over 5 feet. There is some possibility that higher swells will continue into midweek as the remnants of Claudette move well to our east. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 2 AM EDT Sunday for ANZ150-152-154. && $$ NEAR TERM UPDATE...Kimble SHORT TERM...Schroeter LONG TERM...Ekster
Area Forecast Discussion
National Weather Service Huntsville AL
821 PM CDT Sat Jun 19 2021 .NEAR TERM...(Tonight) Issued at 821 PM CDT Sat Jun 19 2021 The center of T.D. Claudette is south of Tuscaloosa this evening, moving NE at 15 MPH. Although most of the rain across North AL has been pretty light so far, rain has picked up from Arab to Fort Payne, with some additional heavier rain bands rotating back into southern Cullman County. Radar estimates are running about 1-1.25 inches per hour under the northern band, though this may be underdoing the amounts in the tropical environment. RAP model data shows that this heavier rain is forming along the nose of the low-level jet and moisture transport maximum, within a low and mid-level theta-e convergence axis, and with precipitable water values around 2 inches. This convergence of favorable features, plus the blowup of heavy rain and convection near Tuscaloosa, does increase my concern for heavy rain and flash flooding slightly. The HRRR and global models suggest these features will be relatively short-lived, with the jet moving east along with the main circulation. So, a watch will not be issued right now, but we will monitor satellite and radar trends closely. The forecast is generally in good shape with PoPs peaking this evening, then tapering off overnight as the low center moves east. Some minor tweaks were made earlier to reflect the drier situation over NW AL, and these look sufficient for now. .SHORT TERM...(Sunday through Monday night) Issued at 249 PM CDT Sat Jun 19 2021 The initial rain shield from Claudette will continue to taper off and shift off to the northeast. Low stratus will hang around through much of the morning, but do expect some breaks to develop from the late morning into the afternoon. This will allow temperatures to warm up into the mid the upper 80s and result in some surface based instability by the afternoon. With the broad remnant circulation of Claudette still in the general area, some isolated to scattered thunderstorms may redevelop during the afternoon on Sunday. Given the very moist air mass in place, heavy rainfall will be the main threat with this activity along with gusty winds. A stout upper-trough is then progged to dig southward into the lower Ohio Valley on Monday, sending a strong cold front SE into the Mid South and Tennessee Valley Monday afternoon and evening. With plenty of deep tropical moisture to tap into, widespread showers and thunderstorms are expected to develop during this window. Sufficient heating ahead of this system will allow for a moderately unstable environment which could support a line of strong to perhaps marginally severe thunderstorms during the afternoon and evening window. The main threats with these storms will be localized damaging winds, but heavy rainfall and perhaps a localized flooding threat may also be realized in locations where training occurs. The front will slowly progress southeast across the area during the overnight hours, with showers and storms gradually tapering off by early Tuesday morning. .LONG TERM...(Tuesday through Friday) Issued at 249 PM CDT Sat Jun 19 2021 Showers and thunderstorms associated with the frontal system passing through the area Monday will quickly taper off on Tuesday as drier air filter into the region. A fairly cool and dry air mass will settle into the region during the day on Tuesday, with northerly winds helping to keep highs in the upper 70s to around 80 degrees in most locations. After another somewhat cool and dry day on Wednesday, expect a gradual warm up Thursday and Friday as an upper-level high pressure begins to nose in from the west. Our surface winds will veer back to a southerly direction and begin the advection of Gulf moisture back into the area. Sufficient heating should allow for some diurnally driven showers and thunderstorms both afternoons. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 649 PM CDT Sat Jun 19 2021 A tale of two different TAFs tonight due to T.D. Claudette: for KMSL, VFR conditions and no rain through midnight, when MVFR to near- IFR ceilings may develop and persist thru 12Z. VFR conditions largely expected from 12Z onward. For KHSV, more difficult conditions will persist until tmrw aftn. IFR/MVFR ceilings have redeveloped on the edge of the outer rain band, and are likely to fluctuate as edge of the band flirts with the terminal. IFR ceilings will become more persistent by 05Z and stay there until 15Z, when some improvement to MVFR is expected as Claudette moves east. Scattered TSRA are possible tomorrow afternoon at KHSV as well, before clearing finally occurs near the end of the TAF period. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...BCC SHORT TERM...AMP.24 LONG TERM...AMP.24 AVIATION...BCC For more information please visit our website at
Area Forecast Discussion
National Weather Service Jacksonville FL
750 PM EDT Sat Jun 19 2021 .UPDATE... A warm front on the northeastern periphery of Claudette has pushed through our southeast Georgia counties this evening, bringing in muggy dewpoints in the mid-upper 70s and adding just enough extra lift and spin to produce a few mini supercells. Further south, the collision of the Gulf coast and Atlantic coast seabreeze boundaries has ignited scattered storms roughly between Ocala, FL and Folkston, GA. Instability over the area is already beginning to wane again, but can`t rule out another strong storm or two completely. Generally SW flow aloft will continue to keep storm motions northeastward through tonight. Lingering storms from the seabreeze should dissipate by midnight, but as Claudette continues its northeastward trek, there may be an overnight increase in coverage of storms over the upper and lower Suwannee Valley. Temperatures overnight are on track to be muggy and stay in the low-mid 70s. && .AVIATION... [Through 00Z Monday] Collision of seabreeze boundaries this evening brings VCTS near GNV/VQQ/JAX for the next couple hours, then drifting towards SSI/CRG/SGJ as VCSH. Another round of showers and thunderstorm to set up near the TAF sites on Sunday. && .PREV DISCUSSION [308 PM EDT]... .NEAR TERM [Through Tonight]... Tropical Storm Claudette is located west of the area over the Mississippi/Alabama border moving northeast, and clouds spiraling out of the system continue to cover the area. Deep moisture from the tropical air mass has taken hold of the region. This morning`s sounding measured PWAT at 1.99 inches, about 0.4 inches above the daily average. Bands of showers will continue through tonight, and we could potentially see some storms this evening if clouds break up enough to allow sufficient surface heating and sea breeze development. The HRRR model suggests a weak Atlantic sea breeze could form and be strong enough to trigger a few storms along the I-95 corridor. Claudette is expected to weaken to a Tropical Depression overnight and move to the northwest of our area. Precipitation chances will continue overnight with highest chances in Southeast Georgia and the Suwannee Valley. Overnight low temperatures will be mild due to cloud cover limiting cooling. Lows will be in the low-to-mid 70s. .SHORT TERM [Sunday Through Monday Night]... Claudette will move to from our northwest to north of the area through Sunday evening while tracking across Georgia. Bands of showers and storms will cross the area throughout the day. Coverage and intensity will be highest over Southeast Georgia closer to the center of Caludette`s track. The Storm Prediction Center has issued a Marginal Risk of severe thunderstorms for Southeast Georgia on Sunday. There will be ample low level moisture and shear that could lead to isolated severe storms with enough daytime heating. Claudette will track over the Carolinas and exit into the Western Atlantic on Monday. Our area will be between a ridge of high pressure to the southeast and a trough of low pressure to the northwest on Monday, which will continue southwesterly flow and continue to bring moisture to the area from the Gulf of Mexico. Scattered showers and storms will be possible again during the day on Monday. High temperatures will be near to slightly below average and low temperatures will be near to slightly above average due to continued cloud and shower coverage. Sunday highs will be in the middle 80s to near 90 with the warmest temperatures closer to the coast. Monday highs will be a couple degrees warmer in the middle 80s to lower 90s with the warmest temperatures closer to the coast again. Overnight lows Sunday and Monday night will be in the low- to-mid 70s. .LONG TERM [Tuesday Through Saturday]... The trough to the northwest will move over the area while weakening Tuesday night into Wednesday. A frontal boundary will approach the area from the northwest Wednesday into Thursday, and it is expected to stall across the area and weaken as weak high pressure builds into the area late in the week. Daily shower and thunderstorm potential will continue through the forecast period, mainly driven by diurnal instability and sea breeze interactions. Showers and storms are expected to be numerous to widespread Tuesday and Wednesday due to increased convergence and moisture associated with troughing over the area and the approaching frontal boundary. Shower and storm coverage is expected to decrease towards the end of the week. Temperatures through the long term period will trend near to slightly below average. .MARINE... High pressure is located to the east of the area waters while low pressure from Tropical Storm Claudette is to the west over the southern US. Claudette is expected to move northeast towards the Carolinas through Sunday and exit into the Western Atlantic on Monday. Winds will increase from the south to Small Craft Exercise Caution levels early on Sunday with the strongest winds over the Southeast Georgia waters. High pressure will shift to the southeast through early next week and winds will shift to become southwesterly. A frontal boundary will approach the area from the northwest mid-week and is expected to stall over the area waters late in the week. Rip Currents: Moderate risk of rip currents at all area beaches will continue through Sunday. .FIRE WEATHER... The area is between high pressure to the east and low pressure from Tropical Storm Claudette to the west. Low pressure will move to the northwest tonight and to the north by Sunday night. Shower and storm potential will continue across the area with higher chances over Southeast Georgia. Winds will become southwesterly Sunday and Monday, and increased transport winds will result in areas of high dispersions over Southeast Georgia on Sunday and Monday. Daily thunderstorm chances continue with highest chances in the afternoons and evenings. No significant fog formation expected. && .PRELIMINARY POINT TEMPS/POPS... AMG 73 87 71 90 72 / 50 60 40 40 20 SSI 76 88 76 90 76 / 50 40 30 30 10 JAX 74 88 74 91 74 / 40 50 30 40 20 SGJ 75 88 74 89 74 / 50 40 30 30 10 GNV 74 86 72 87 71 / 30 50 50 50 20 OCF 75 88 74 89 73 / 20 40 40 50 20 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. &&
Area Forecast Discussion
National Weather Service North Platte NE
653 PM CDT Sat Jun 19 2021 .SHORT TERM...(This evening through Sunday night) Issued at 137 PM CDT Sat Jun 19 2021 A modest upstream shortwave is evident across central WY per water vapor imagery early this afternoon. Meanwhile at the surface, a warm front was analyzed across KS. The better moisture (surface dew points 65-70) are located near and pooling just to the north of this boundary roughly along the I-70 corridor across northern KS. This moisture will try and work northward late this afternoon and early this evening as the low-level flow veers more to the southeast. Even so, dew points will struggle into the upper 50s along and south of I80 and less to the north of I80. The limited moisture return will be of concern as convection moves east-southeastward out of the Panhandle ahead of the WY shortwave late this afternoon and evening. The Hi-Res short term models are hinting that the stronger and potentially severe storms will likely stay mostly along and south of I80, where the better moisture will reside. The main severe threat seems to be from strong wind potential and a lesser threat for hail. HRRR advertises a swath of significant gusts of 45-55 kts this evening south of I80 as the line of storms progresses across the area. Late tonight a cold front will begin to move southeast into northwest Nebraska driven by a potent shortwave moving southeast into the Dakotas. This front will cross the area Sunday ushering in a cooler and drier airmass from Canada. It will take some time for this airmass to fully move into the area, but northwest Nebraska will only see highs in the mid 70s Sunday with lower to mid 80s across the central and southwest portions of the state. A quick moving disturbance within northwest flow aloft will cross the central Rockies into the western High Plains Sunday night. Warm/moist advection ahead of this wave could trigger a round of elevated thunderstorms Sunday night across the Panhandle through southwest Neb. and current pops will be maintained. .LONG TERM...(Monday through Saturday) Issued at 137 PM CDT Sat Jun 19 2021 The brunt of the cooler airmass will be located across the region on Monday. H85 temps will range from 14-19C from northeast to southwest across the area, which will yield highs generally in the mid to upper 70s. Ridging aloft quickly builds in TUE-THU with highs back into the 90s. Then towards the end of the week and next weekend, models have been advertising an upper level long wave trough crossing Canada into the Northern Plains. Models have been struggling with the amount of cooler air that may filter south with this feature, but at least a few degrees of cooling seems likely. Ensemble means of both the GFS and ECMWF are in the mid 80s for Friday and Saturday. The official forecast is just a few degrees higher than that at this point. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 651 PM CDT Sat Jun 19 2021 VFR conditions are expected to largely prevail through tomorrow afternoon. The lone exception will be this evening, when thunderstorms move through southwest NE and may lead to brief local MVFR. Storms across southwest Ne will have a risk for strong wind gusts and hail. These storms quickly exit the area from west to east tonight. Some northerly LLWS looks to develop across portions of northern Nebraska overnight. Otherwise, expect winds to back from southeasterly to northerly and remain gusty as a cold front passes tomorrow morning. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Taylor LONG TERM...Taylor AVIATION...Roberg
Area Forecast Discussion
National Weather Service Louisville KY
933 PM EDT Sat Jun 19 2021 .Forecast Update... Issued 930 PM EDT Sat Jun 19 2021 Muggy conditions ongoing for the Ohio Valley region, with a pool of low 70s dewpoints along and west of I-65 and readings more around 70 for the rest of the state, per the Kentucky Mesonet. Atmosphere appears still capped over our region, but SPC mesoanalysis shows some instability peaking just to our north, over central IN. Some subsidence is occurring here now though, thanks to the stronger cells that are over the MO/IL border area tonight. Still cannot rule out a very isolated storm popping up overnight, but trimmed those chances even farther north, to a roughly Paoli, IN to Bedford, KY line. Issued 555 PM EDT Sat Jun 19 2021 Warm air above an inversion at 900 mb has kept most of the region capped through the afternoon. AMDAR sounding from 19Z sounding showing this well, and RAP forecast soundings agree for SDF. Over near HNB the RAP shows a weaker cap, with convective temperatures of 89-90. Current reading there is in upper 80s, so its not out of the question that we could get an isolated storm to pops out of the cumulus field that has popped up near there. Rest of the region should be harder to see development given extensive cloud cover streaming northward from TC Claudette. Did go in and change the point and click forecast to lower pops to slight chance along and north of I-64. && .Short Term...(This evening through Sunday) Issued at 245 PM EDT Sat Jun 19 2021 Widespread mid and high clouds from both TS Claudette and a couple rounds of showers and thunderstorms have kept temperatures in the 70s over southern Indiana and some of far north central Kentucky this afternoon, keeping convective redevelopment in check. Winds aloft weaken significantly tonight and little if any thunderstorm development is expected. The best chance for something to pop would be isolated development along and north of the I-64 corridor. Low temperatures tonight should generally be in the 65-70 degree range with a light SSW breeze. Tomorrow an upper level impulse is expected to move from Missouri to Indiana by afternoon. However, sounding progs are showing warm temperatures in the 850-700mb layer and 700mb charts show temperatures warming to around 11-12C by afternoon. Atmospheric cross-sections show some subsidence on the northwest side of former Claudette as the tropical remnants move into the southern Appalachians. The front to our northwest will remain well to our northwest. Will allow for an isolated thunderstorm in southern Indiana, but otherwise keep things dry. Sunday will be hot and muggy with afternoon highs in the upper 80s and lower 90s on 10-15 mph southwest winds. Afternoon heat index readings will peak in the 90s. .Long Term...(Sunday night through Saturday) Issued at 257 PM EDT Sat Jun 19 2021 ...Strong Storms and Heavy Rain Possible Monday... Long term forecast likely begins dry Sunday evening, but a strong cold front will be in the process of pushing southeast across the Midwest. A tightening pressure gradient and warm SW flow will result in a warm night with lows ranging through the 70s. Deep convection is likely to initiate along the cold front late in the day Sunday and surge southeast in a linear mode Sunday night. Weakening storms could pose a gusty wind threat in our southern Indiana counties by 09-12z Monday. Monday afternoon and evening, an amplifying upper level trough swings eastward over the mid-Mississippi Valley. Plenty of mid-level PVA over the warm sector and sfc cold front will result in plenty of lift for renewed development. Sfc cold front could be near the Ohio River as early as 15z Monday, so portions of central and eastern KY may see the strongest destabilization prior to fropa. There is a modest increase in WSW flow aloft, but deep-layer shear is generally 25-30 kts in the warm sector with stronger shear lagging the cold front slightly. Given the linear forcing and largely unidirectional wind profile, the main concern is damaging winds. A very moist airmass will support torrential rainfall rates and a marginal risk for flash flooding as well. Highs Monday will be in the mid 80s to around 90. Showers and storms exit off to the east late Monday night/early Tuesday, and temperatures drop into the mid 50s to lower 60s by daybreak Tuesday. Upper trough axis remains overhead Tue with cool, northerly low-level flow and sfc high pressure building in from the west. Afternoon highs likely only top out in the low to mid 70s for most, perhaps upper 70s near Bowling Green. Tue night looks cool with light winds and lows in the low to mid 50s. Upper level ridging builds over the southern Plains Wed and Thu with heights rising from the SW. Expect warmer temps Wednesday afternoon, but still really comfortable with highs in the upper 70s/lower 80s and dewpoints in the 50s. Mid/upper 80s highs look more likely Thursday, and the atmosphere does begin to moisten ahead of the next low pressure system. Expect increasing shower and storm chances late in the week and heading into next weekend. && .Aviation...(00Z TAF Issuance) Issued at 715 PM EDT Sat Jun 19 2021 Expect a steady south to southwest wind most of this period as we remain nestled in between high pressure to our east and low pressure over the Midwest. Some warm air above the surface should keep storm threats out of the region for this period. Cannot rule out some brief stratus overnight/early Sunday, but forecast soundings show this should remain above no aviation concerns there. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...RJS Short Term...13 Long Term...EBW Aviation...RJS
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1014 PM CDT Sat Jun 19 2021 .MESOSCALE DISCUSSION...| 1013 PM CDT Mesoscale Update... Isolated convective cells continue to develop late this evening, along a southward moving combined cold front/lake breeze along and south of the I-80 corridor across northeast IL and northwest IN. Expectation is that these may fester through late evening as the boundary drifts south, before diminishing/decaying around midnight. Cells along the boundary on the Illinois side of the state line appear to have benefited from a slight increase in flow above the boundary layer with diurnal cooling after sunset. While parcels appear to be capped with respect to surface-based instability, SPC mesoanalysis indicates 2000-3000 J/kg of MUCAPE south of the frontal boundary for elevated parcels along with 30-35 kts of effective deep shear. Not surprisingly, some supercellular structures have been noted this evening with the more robust updrafts farther east in northern IN. Less robust nature of updrafts along the boundary farther west into IL may be linked to slightly warmer mid-level temps, with a pronounced warm layer around 700 mb evident to the northwest in a comparison of DVN and ILX 00Z RAOBs. RAP forecasts indicate a gradual warming of 700 mb temps into east central IL and northwest IN late this evening/midnight hours, which would suggest thermodynamic profiles may become less favorable for continued deep convection with time over the next couple of hours. More robust cells from the LOT/IWX border eastward may be capable of torrential downpours (especially given repeated development along the western flank) and some wind/hail potential. Farther west into our area the main impacts would likely be isolated brief downpours and a few lightning strikes. Ratzer && .SHORT TERM... 234 PM CDT Through Sunday night... Focus remains on the severe weather potential across northern Illinois and northwest Indiana Sunday afternoon and evening. A strong trough digging into the northern Rockies this afternoon will pivot across the central Great Plains and into the western Great Lakes through Sunday night. Meanwhile, the slow-moving cold front over the northern CWA early this afternoon is expected to stall across central Illinois tonight, then lift back north as a warm front on Sunday ahead of the advancing trough and associated surface low pressure. A cold front will then sweep SE across the region Sunday night. While the overall synoptic set-up is fairly straight-forward, evolution of upstream convection introduces some significant complications with the forecast. But, the overall severe thunderstorm threat on Sunday hinges the most on two things: 1) The potential development and subsequent track of an MCV over the central Plains into the western Great Lakes 2) Ultimate position of the warm front by late Sunday afternoon. By early Sunday morning, steeper mid-level lapse rates will have advected back over the region. Subtle low to mid-level isentropic ascent supports the potential for isolated elevated convection lifting northeast across the CWA from around daybreak through mid- morning. While a poor moisture profile through the column suggests this period should remain dry, any narrow layer of moisture non- resolved by current forecast guidance would be enough to fuel convection (as was seen a couple days ago). Focus then turns to the possible MCV tracking into the region during the later morning through mid-afternoon. While not surprising, there are significant disparities in how guidance is handling this feature. However, the envelope of scenarios favors the MCV shifting ENE into northern Illinois by mid-afternoon. By this time, the environment will have sufficiently destabilized south of the warm front to support organized severe convection with any stronger MCV. A hybrid of multicell bowing clusters with embedded supercell features would be expected. Damaging winds, isolated very large hail, and a brief tornado near the warm front are all possible. More deep convection is then expected to develop on the cold front as it shifts southeast across the area Sunday evening. Again, the evolution of the afternoon MCV will determine how far north or how worked-over the environment is ahead of the front. But conditions favor development of a QLCS that will feed off a quickly recovering low-level airmass on a 50-60kt LLJ. Embedded bowing segments and possibly supercell structures support a damaging wind threat across northern Illinois through the evening hours. A few embedded tornadoes are also possible with the increasing low-level shear and nature of the QLCS. While this forecast provides the most likely scenario, the overall evolution will remain less clear until convection initiates in the central High Plains this evening and begins to (or fails to) develop a small convective cluster. Make sure to continue to check forecast updates over the next day. Kluber && .LONG TERM... 249 PM CDT Monday through Saturday... After the frontal zone clears the area Sunday night, northwest flow at the surface becomes established ahead of a broad dome of high pressure across the Central Plains. This will bring a drier and cooler airmass into the area for the start of the week. Southerly flow then returns by Wednesday as the surface ridge slides east into the Ohio Valley. Despite the warmer and more humid airmass, precip chances do not climb significantly until later in the week when the upper ridge also breaks down and models show another cold front gradually making its way toward the area. If trends hold, presently Friday appears to be the best bet for widespread showers and thunderstorms with the passage of the front. Lenning && .AVIATION... For the 00Z TAFs... Aviation Forecast Concerns: * Combination lake breeze/back door cold front moving across Chicago terminals at this time producing a wind shift to northeast. * Current frontal boundary lifts back near/across terminals Sunday as a warm front, though confidence on exact location and wind directions is relatively low. * Potential for two periods of strong to severe thunderstorms across the area Sunday afternoon and Sunday evening. Combined lake breeze/cold front was pushing south across the Chicago terminals as of 6:30 pm. Winds have shifted northeast at KORD and KMDW and will remain there through the evening/overnight. A few isolated showers and thunderstorms have been percolating along the boundary, though these should be mainly southeast of the terminals shortly with no additional activity expected in the immediate vicinity through tonight. Winds will become light easterly overnight, trending southeasterly Sunday morning. A trough of surface low pressure will then develop eastward across the Plains later tonight and into the upper Midwest on Sunday. Developing southerly return flow will lift our current cold frontal boundary back north as a warm front Sunday. Winds will turn southeast in the morning ahead of the warm front, with winds becoming gusty south-southwest south of the boundary by afternoon. Models are a little different in depicting how far north the front lifts however, offering somewhat lower confidence at this time with exact wind directions for the terminals (more southeast if the boundary is to the south, more south-southwest and stronger if the boundary lifts north). For now have indicated the boundary lifting north of KDPA-KORD by early afternoon. Looking much farther to the west this evening, a large complex of thunderstorms has developed off the front range of the Rockies in association with an eastward-moving mid-level disturbance. Models have been steadfast in propagating this convectively-enhanced disturbance east across the Plains overnight and across our area on Sunday. Initially this looks to present the potential for some light showers or sprinkles by mid-Sunday morning from a VFR mid level deck, but with increasing strong thunderstorm chances by mid-afternoon as the warm, humid and unstable air mass along and south of the warm front destabilizes. This threat looks to be primarily during the mid-late afternoon hours Sunday, with a break toward evening as the mid-level wave passes. Thunderstorm potential then looks to increase again toward mid-evening as another upper wave and a surface cold front approach the area. Both periods of thunderstorm potential could include strong to severe storms. Surface wind field may be convectively disturbed between rounds 1 and 2 as well, lending low confidence in wind directions during the late afternoon/evening hours. Ratzer && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at: