Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/03/18


Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
540 PM MDT Sun Sep 2 2018 .AVIATION... 00Z TAF CYCLE Tstm activity continues to favor the high terrain of the west-central and northern mtns as well as along a few sfc bdrys over the east plains of NM. Brief MVFR conditions can be expected with any of the strong storms as they pass. Removed VCTS across the NW at KGUP and KFMN where new strong convection is not expected to develop the rest of this evening. Some storms could drift into the RGV near KABQ, KAEG, and KONM over the next few hours. The HRRR is depicting an outflow bdry emanating from convection over the Sangre`s SW into the RGV to KSAF down to KABQ later this evening from 02Z-07Z, and can see this already occurring at KLVS. This may keep convection going later toward midnight, but confidence is not high enough to see anything more than a windshift and VCSH from this feature. The east plains may see shower activity continue well into Monday morning. 24 && .PREV DISCUSSION...327 PM MDT Sun Sep 2 2018... .SYNOPSIS... A weak, but broad, trough of low pressure is over the southwestern states with isolated to scattered showers and thunderstorms being observed over portions of New Mexico. Thunderstorms have initially developed over the higher terrain, but are beginning to expand into lower elevations such as the eastern plains of the state. Storms could sustain themselves into the overnight hours in the eastern plains. A fairly similar extent of thunderstorm coverage is expected into Monday and Tuesday while temperatures remain a few to several degrees below average for early September. A weak cold front will then back into the state Wednesday, keeping the cooler trend going. && .DISCUSSION... The longer wave trough over the western states is keeping mid- tropospheric pressure heights lowered over the area and hence cooler than average temperatures are prevailing. Moisture is highest over the eastern and southern tiers of NM, running slightly above average with regards to PWAT climatology, while areas within the northwestern quarter of the state are running near to slightly below average. Despite the cooler temperatures, the boundary layer has destabilized sufficiently for high terrain storms to fire, and these are quickly expanding over the eastern plains. This trend should continue through the evening and overnight per the NAM/HREF/HRRR/RAP guidance. Into tomorrow, the long wave trough will be retained, although an embedded short wave will be lifting northeastward into CO. Similar to today, storms on Monday are expected to initiate over the west central zones surrounding the Continental Divide and and the central mountain chain during the afternoon before expanding into the plains. The southerly flow will back ever-so-slightly to more of a south southeasterly component, allowing Gulf moisture to continue feeding into the plains. The trough will start to lose a bit more definition into Tuesday as the speed max aloft begins to weaken. Again the plains will observe a continued slight backing in the surface winds with moisture being retained best over the eastern plains where PWATs will stay above an inch. The northwest plateau will continue to observe less moisture and lower storm prospects through Tuesday while the area-wide below normal temperatures persist. The weak back door cold front will ease into NM on Wednesday, spreading some of the deeper moisture from the plains westward into the Rio Grande valley and western portions of the state. This will increase storm chances in these areas late Wednesday and into the evening. Recycling of moisture will keep storms in the forecast through Thursday, but as the weekend approaches the strengthening eastern Pacific high (west of southern CA) will begin suppressing storms and cutting off moisture. 52 && .FIRE WEATHER... Afternoon rounds of showers and thunderstorms are expected to continue through most of the week with the focus for the storms to be mostly on the higher terrain. A backdoor front will push down the Eastern Plains on Wednesday, bringing with it a minor increase in winds and slightly higher afternoon RH values. Humidity recoveries are expected to remain excellent through the week with below normal temperatures. A warming and drying trend is expected to being on Friday as high pressure begins to build over the Southwest. 54/Fontenot && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
852 PM CDT Sun Sep 2 2018 .UPDATE... Issued at 851 PM CDT Sun Sep 2 2018 Forecast in fine shape with just a couple minor changes made. HRRR runs this evening continue to advertise a few late night showers so will leave that in the forecast. Temperatures appear fine. && .SHORT TERM...(This Evening through Monday) Issued at 147 PM CDT Sun Sep 2 2018 As of 1 PM, high pressure is over far northeast Montana and northwest North Dakota, with a ridge stretching south into north central SD. The brief period of gusty northerly winds this morning to the present time is tied to the tighter pressure gradient between the departing front and arriving high. These winds should gradually diminish through the rest of the afternoon. Temperatures are currently in the 70s under a mostly sunny. GeoColor imagery from GOES-East does indicate a little bit of smoke over the area and you can get a slight smell of it outside of our office. The high in North Dakota will continue to the east this evening and overnight, leading to low level winds veering to the southeast by tomorrow morning. Should see winds becoming gusty out of the southeast in the afternoon hours tomorrow (mean momentum transfer in upper teens to lower 20s for most locations), as the pressure gradient again increases between the departing high moving into the Great Lakes region and another cold front moving into western ND and far northwest SD by 00Z Tuesday. The other item of concern is the precipitation potential overnight into tomorrow. A mid level ridge axis will shift through the area tonight, shifting winds aloft to the southwest and increasing warm air advection. Some differences in the northward extent of the best mid level moisture, with the NAM showing the greatest moisture and northward extent. Will follow a general model consensus for sky and precipitation potential. Looks like there will be a pocket of clouds and maybe a few showers pushing north along the Missouri River after midnight. Farther east, the departing high may may leave enough low level dry air to attempt to hold off the clouds some. Overall, expect at least partly to mostly cloudy skies tomorrow for most locations. As for PoP forecast, confidence is low on coverage/location, but did try to show some slight chance PoPs for the initial push of warm air advection into the south central part of the CWA (CAMs give varying solutions but all in that general area). There is some instability moving into the area tonight (MUCAPE gradient of 0 J/kg over northeast SD to 500-1000 J/kg near the Missouri River), so will show some thunder potential. If a storm got going, would expect some small hail as they will likely be elevated and based in the mid level warm air advection regime. Finally, another wave of precipitation is possible over the far southeast CWA during the latter part of the afternoon. This precipitation will be tied to a surge of mid level moisture under south-southeast winds aloft ahead of an upper low lifting northeast out of the Four Corners region. .LONG TERM...(Monday Night through Sunday) Issued at 241 PM CDT Sun Sep 2 2018 The long term starts out with a short wave trough out west moving across the northern plains Monday night through Tuesday. At the surface, a cold front will push across our cwa on Tuesday. There will also be weak short wave energy coming into our region from the southwest Monday night and Tuesday. All three of these features will result in chances of showers and storms for Monday night into early Tuesday evening. Otherwise, the upper level flow will be westerly for Wednesday and Thursday. Modest upper level ridging will then move over our region as upper level troughing moves into the western U.S. Friday through the weekend. Thus, Tuesday night into Saturday morning is expected to be mainly dry. Upper level troughing coming through Saturday afternoon into Sunday will bring back some chances of showers and storms. Temperatures through the period will be mostly from near to 5 degrees below normal mostly in the 70s and lower 80s. There will likely be some upper 60s in the northeast on Wednesday. Along with these temperatures will come some fall-like humidity. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) Issued at 653 PM CDT Sun Sep 2 2018 VFR skies/vsbys are expected through the dark hours at all terminals. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...TDK SHORT TERM...SRF LONG TERM...Mohr AVIATION...TDK
Area Forecast Discussion
National Weather Service La Crosse WI
644 PM CDT Sun Sep 2 2018 .SHORT TERM...(This evening through Monday) Issued at 208 PM CDT Sun Sep 2 2018 While there will be showers and storms around the area through Monday, this is looking to be a relative lull in the heavy rain threat. The boundary that had been south of the area the last couple of days has become very diffuse. Still some hint of it across central Iowa where there is a subtle wind shift and slight increase in the dew points. There is also a cold front moving southeast across Minnesota as high pressure builds in behind the front over the Dakotas. Looking at several runs of the RAP and the 03.12Z NAM, it looks like both of these boundaries will be a player for the local area. The weak boundary across Iowa is expected to shift north through the evening while become even more diffuse while the cold front gets pushed to about the Interstate 90 corridor overnight as the high pressure moves east toward Lake Superior. The low level moisture transport axis looks to be from Missouri into lower Michigan, well ahead of the advancing cold front. The ML CAPE axis also looks to remain southeast of the area, but enough remains to maintain at least a threat of thunder. The main axis of showers and storms is expected to gradually shift southeast across the area this evening and primarily be out of the area for much of the overnight hours. The boundary pushed in by the area of high pressure tonight will start to lift back to the north as a warm front Monday. This will allow the moisture transport axis to shift back to the west and while still weak, will be focused more into the area. This should allow for a general increase in showers and storms through the day, especially south of Interstate 90. While there could be a brief period of heavy rain the storms Monday, there does not look to be a threat of widespread heavy rain or flash flooding with the general weak moisture transport and the highest precipitable waters remaining south of the area. .LONG TERM...(Monday night through Sunday) Issued at 208 PM CDT Sun Sep 2 2018 Main concern is possible heavy rain/flood threat through mid-week. The surface boundary is forecast to lift northward across the area as a warm front Monday night ahead of an upper shortwave trough. Warm advection and increasing low-level moisture transport will help to foster showers/storms. The 02.12Z NAM focuses the strongest moisture transport and convection north and west of the area. However, confidence in details in this type of scenario with a boundary lifting north is not all that high at this range given potential contamination from convection. Locally heavy rainfall will be possible with any storms given the environment. If the warm front does lift north of the area could see a relatively quiet Tuesday morning until the cold front approaches from the west. At least modest mid-level height falls ahead of the broad upper will overspread the region Tuesday afternoon and night. Expect showers/storms to increase as the front slowly sags south Tuesday into Wednesday. A very warm, anomalously moist environment will favor the potential for heavy rain/flooding. Some uncertainty remains as to where this potential will be highest and the degree of training of storms that will occur along the front. However, the later Tuesday into Wednesday period will be one to watch closely, though, especially given antecedent conditions. Mid-level flow/shear remains on the marginal side south of the front and lapse rates are weak, but could see a few stronger storms later Tuesday. As the upper waves passes to the east, surface high pressure will begin to build south on Wednesday with drying across northern parts of the area. A generally weak upper flow pattern is expected late this week. Surface high pressure across the northern Great Lakes should lead to a period of drier weather late this week into the weekend over much of the area. However, given the weak flow and suggestion that various shortwaves may lift northeastward in weakly confluent flow on the western periphery of the Southeast/Mid-Atlantic ridge, some shower/storm chances may persist into late week, especially across southern areas. Temps will cool from the 70s to low 80s early this week to the upper 60s and 70s later this week behind the front. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 644 PM CDT Sun Sep 2 2018 Showers and storms are southeast of LSE and RST and should remain there for much if not all of tonight, with winds becoming light as a weakening frontal boundary slides into the area. With earlier rain, light winds, and some breaks in the sky cover at times (just mainly high clouds), fog should be a pretty good bet later tonight, some of which will become dense fog both LSE and RST. Not entirely sure just how fast fog will develop, but a good first guess is roughly 04-07Z, with the thickest fog expected either side of sunrise, when visibility could be 1/4 mile or less, particularly at RST (though possible at LSE as well). Fog will likely lift into a stratus layer for a time Monday morning, perhaps trying to scatter out for the afternoon as some additional showers and storms attempt to develop later in the day. Confidence is low in how much coverage of storms will exist through 00Z, with much better chances arriving into Monday evening and night. && .HYDROLOGY... Issued at 208 PM CDT Sun Sep 2 2018 The highest potential for additional heavy rains and possible flash flooding, appears to be focused on the late Tuesday afternoon into Tuesday night period. The next cold front will be advancing into the area with strong moisture transport focused into the front. An axis of high precipitable waters, possibly in excess of 2 inches, will reside ahead of the front. The concern is how far north will the nose of the moisture transport axis be to focus the heaviest rain threat. Also uncertain how much training there will be ahead of the north/south oriented front that looks to be fairly progressive. Flooding continues along the Kickapoo River and for now, levels continue to go down. See the latest flood statement for more details. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...04 LONG TERM...JM AVIATION...Lawrence HYDROLOGY...04
Area Forecast Discussion
National Weather Service Bismarck ND
952 PM CDT Sun Sep 2 2018 .UPDATE... Issued at 952 PM CDT Sun Sep 2 2018 Latest satellite imagery and surface observations continue to show a mostly clear sky. Surface high pressure centered over the Devils Lake region is now resulting in a weak southeasterly wind across central North Dakota. Did lower overnight temperatures into the 40s for all of central ND based on current trends and dewpoints. Lower level clouds in south central South Dakota still on track to move across the southern border 12z-20z Monday. Have bumped up cloud cover per latest satellite imagery and RAP13 925mb-850mb RH field Monday morning into the afternoon, mostly for the James River Valley. The CAM`s show isolated showers developing later tonight in eastern South Dakota in association with a strengtheninglow level jet. These showers are forecast to weaken as they approach the border mid to late Monday morning. The 00Z model runs are coming in and the NAM is slower and a bit farther west with the convection Monday evening, initiating between 00z-03z; while the HRRR and other CAM`s show an initiation between 22z Monday and 00z Tuesday. And while the thunderstorms are still contained initially in western North Dakota per HRRR, the thunderstorms are farther east than where the NAM places its thunderstorm solution at 03z Tuesday. A few strong to severe thunderstorms Monday late afternoon and evening remain in good standing at this time. UPDATE Issued at 631 PM CDT Sun Sep 2 2018 Latest visible satellite imagery shows a clear sky for all but the far northern tier counties, where mid and high clouds were observed moving from west to east across the southern Canadian prairies. A thin wisp of smoke aloft can also be seen stretching from northern Minnesota back into central North Dakota and portions of Montana. Surface observations show dewpoints in the lower to mid 40s in conjunction with todays high temperatures. These dewpoints usually serve as a good proxy for overnight lows given a decent radiational cooling inversion. Per BUFKIT soundings tonight, central North Dakota should see good radiational cooling with a clear sky and light winds. May need to lower temperatures a few degrees across south central ND given the dewpoints mentioned above, and will monitor the trends this evening before making any changes. Scattered to broken low clouds (3500ft to 6500ft agl) in south central and southeastern South Dakota were shifting north very slowly. The RAP 925mb-850mb RH field captures this well, and as our low level winds turn southerly and increase late tonight, should see some of these clouds reach far south central and the James River Valley after 12z Monday. Current forecast is on track. && .SHORT TERM...(This evening through Monday) Issued at 229 PM CDT Sun Sep 2 2018 Main forecast issue in the short term period will be temperatures and thunderstorm chances late Monday. Currently, high pressure is situated over western and central North Dakota with nearly full sunshine over the entire forecast area. Northerly winds were diminishing east with light and variable winds west. Last night was a good radiational cooling night with morning lows this morning dropping into the upper 30s over portions of the west. It looks to be another good radiational cooling night tonight over central North Dakota, although we should remain in the 40s. In the west it should cool quickly this evening but we will see an increasing return flow on the back side of the surface high late tonight. Adjusted lows downward most areas, especially east and normally cool areas of the west. A shortwave trough moving tracking across the southern Canadian provinces will induce lee side cyclogenesis over the Canadian and northern Rockies late tonight with the surface trough tracking east to the Montana/North Dakota border by 00 UTC Tuesday. This should allow for plenty of heating over easter MT and western ND Monday afternoon within the thermal trough under sunny to mostly sunny skies. This will set the stage for convection late in the day on Monday, but moreso Monday night. We did raise high temperatures across much of the central and especially western ND Monday with some areas of the far west reaching the upper 80s. We kept some slight chance pops in the far west but limited them to the 21-24 UTC timeframe. .LONG TERM...(Monday night through Sunday) Issued at 229 PM CDT Sun Sep 2 2018 An unstable but capped airmass is expected Monday afternoon along and ahead of the aforementioned surface trough. We expect a moderately unstable airmass with steep lapse rates developing over western North Dakota Monday afternoon. Initially capped, the heating along the trough, the forcing from the mid level trough and trailing cold front is expected to generate convection over western ND late Monday afternoon into early Monday evening. Although not perpendicular, the bulk shear appears to be at enough of an angle to the surface trough that convection may be discrete when it initially develops with shear becoming more parallel to the trough and the cold front late in the evening and overnight. Bulk shear is reasonable around 30 to 40 knots early Monday evening. Thus during the first half of the evening we think discrete supercells possibly transitioning to multicellular clusters are possible. Large hail up to half dollar size and wind gusts to 70 mph would be the main threats with cells that can maintain a rotating updraft within this deeply mixed boundary layer. Although directional shear and low level helicity is present, the expected high bases, and high LCL`s should limit the tornado potential. As convection tracks into central ND, it will meet up with a more strongly capped environment and by this time with the diurnal trend in a downturn, surface based instability will be diminishing. Thus our confidence for severe convection as the mode transitions to possibly more of a QLCS structure, is less. With the SPC upping the severe potential to a slight risk over western and a bit of central ND Monday evening, we did add the mention of severe wording in the gridded forecast and messaged this in social media posts. Later shifts can adjust as needed over central ND as we move closer to this timeframe. Certainly as we go toward Tuesday morning models suggest convection diminishing as it pushes into eastern portions of central ND as the cold front outraces the convection. However showers and isolated thunder chances will remain over the southern James River Valley into early Tuesday afternoon. By Tuesday evening, cool Canadian high pressure buildings in. This will give us another taste of fall, with highs in the mid 60s to lower 70s and lows in the upper 30s and 40s through Wednesday night. Flow aloft will become zonal through mid-week, but no disturbances are currently being resolved by long-range guidance. A return to more active weather appears likely heading into next weekend as an upper-level shortwave moves onto the Pacific Northwest coast. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 631 PM CDT Sun Sep 2 2018 A strong cold front will begin to approach the western terminals towards the end of this taf period. Vfr cigs/vsbys are expected, however, cigs around 3500ft agl are anticipated at KJMS by 18z Monday as low level moisture and clouds shift from southern South Dakota into southern North Dakota Monday morning. A vcts was added to KISN/KDIK toward 00z Tuesday, which will be ahead of the advancing cold front posing a risk for severe thunderstorms from 00z through 06z Tuesday. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...TWH LONG TERM...TWH AVIATION...KS
Area Forecast Discussion
National Weather Service Brownsville TX
316 PM CDT Sun Sep 2 2018 .SHORT TERM (Now through Monday Night): Satellite and radar images continue to indicate convection developing along the northern edge of the CWA as well as across the Mexican plateau this afternoon. The 500mb low across the upper Texas coast and the 500mb high across northeast Mexico is providing subsidence across deep south Texas but monsoonal moisture to the west and moisture with the broad circulation associated with the upper level low to the northeast warrant a mention of isolated showers and thunderstorms across the northern ranchlands late this afternoon and across the western portions of the CWA early this evening especially as the HRRR continues to prog convection developing across western and northern portions of the CWA late this afternoon into early this evening. Low to mid level moisture will remain high to the northwest and northeast of deep south Texas Monday with the upper level ridge across northeast Mexico providing subsidence across the Rio Grande valley. Will likely see a repeat of today as far as temperatures and rain chances so will go with persistence for temps and POPS Monday and Mon night. LONG TERM (Tuesday through Sunday): Deep tropical moisture will increase across the eastern portions of deep south Texas on Tuesday, with precipitable water values over two inches by Wednesday. The elevated moisture will support higher rain chances across the CWA Tuesday and Wednesday. The long term forecast will remain challenging as the global models forecast, with high certainty, a tropical system moving across the northeastern Gulf of Mexico Monday through Wednesday. The system will then move inland along the north Gulf Coast, where heavy rainfall will be possible. Impacts to the CWA will remain scant at this writing. As such, isolated to scattered showers and thunderstorms will continue locally through the rest of the period as moisture lingers in the area under modest mid level ridging. Warmer than average temperatures will continue, with lows from 75 to 80, and highs from the mid 90s east to triple digits west. Heat index values will be mostly in the 103 to 108 degree range. && .MARINE (Tonight through Monday night): Seas were near 3 feet with south to southeast winds near 8 knots at buoy020 this afternoon. Moderate to strong southeast winds will develop offshore the lower Texas coast tonight as surface low pressure across northeast Mexico and surface high pressure across the eastern Gulf of Mexico provides a strong pressure gradient across the western Gulf. Will word SCEC for the offshore waters tonight as a result. Winds will diminish across the coastal waters Monday as the pressure gradient weakens across the lower Texas coast slightly but winds will be slightly higher across the bay waters than offshore. Winds will increase offshore the lower Texas coast Mon night but not as strong as tonight. Tuesday through Friday night: Light to moderate east to southeast winds and low to moderate seas will prevail through the long term. The current wave models do not develop much in terms of swell from the system forecast to strengthen while moving into and across the northeast Gulf during the upcoming wk. Scattered to numerous showers and thunderstorms will however move toward and over the lower Texas coastal waters. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 81 97 80 93 / 10 10 20 30 BROWNSVILLE 81 97 78 96 / 10 10 20 30 HARLINGEN 78 100 77 96 / 10 10 20 30 MCALLEN 81 102 80 99 / 10 10 10 20 RIO GRANDE CITY 81 103 79 101 / 20 10 10 20 SOUTH PADRE ISLAND 82 92 81 88 / 10 10 20 30 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV 61/54/62
Area Forecast Discussion
National Weather Service Cheyenne WY
519 PM MDT Sun Sep 2 2018 .SHORT TERM...(This evening through Tuesday night) Issued at 150 PM MDT Sun Sep 2 2018 Tonight...Cumulus field bubbling up nicely over the mountains. CAPES of 500 to 1500 J/kg exist over the southern Nebraska Panhandle. With best cumulus development over the southern Laramie Range, will hold onto isolated thunderstorms into the evening over the southern Laramie Range, and dry elsewhere based on cumulus development seen on visible satellite imagery. Labor Day...A slow moving shortwave trough aloft moves to southeast Wyoming in the afternoon with a surface convergence axis setting up just south of the Colorado state line, thus will continue with isolated afternoon thunderstorms along and just north of the Colorado state line. Monday night...Isolated thunderstorms continue into the evening near the Colorado state line, then end. Tuesday...Weak westerly flow aloft with low level easterly upslope over our counties. With a well defined low and mid level theta-e ridge axis over our counties, expect isolated to scattered afternoon showers and thunderstorms south of a Rawlins to Lusk line. NAM and GFS MOS differ considerably on maximum temperatures, so will compromise between the models for high temperatures. Tuesday night...With plenty of low and mid level moisture continuing over our counties and weak upslope, will continue with isolated to scattered showers and thunderstorms all night, mainly along and east of Interstate 25. .LONG TERM...(Wednesday through Sunday) Issued at 150 PM MDT Sun Sep 2 2018 12Z medium range models/ensembles show the persistent upper level trough over the central Rockies finally exiting into the Great Plains by the end of the week. Until then, the weather pattern will remain somewhat unsettled, with widely scattered showers/tstorms and cooler than normal temperatures. High pressure at the surface and aloft will bring drier conditions and normal temperatures by Saturday. It will be breezy west of the Laramie Range Saturday ahead of a upper level trough over MT. The trough moves east along the US/Canadian border, driving a cold front southward into the CWA. The GFS develops scattered convection along/behind the front, with the Euro depicting little or no precipitation. Kept next weekend/s forecast dry. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 516 PM MDT Sun Sep 2 2018 Confidence increasing that we will see some low stratus over the southern Nebraska Panhandle tonight as moist southeasterly flow develops. Main terminal to be impacted look to be KSNY and KAIA. HRRR has timing around 10Z for KSNY and 12Z for KAIA. Will see what happens with KBFF, but for now, kept them VFR. && .FIRE WEATHER... Issued at 150 PM MDT Sun Sep 2 2018 Will need to watch Carbon County through early evening with near critical conditions, i.e., low humidities and wind gusts approaching 25 mph. Low humidities expected Labor Day afternoon over Carbon and Converse counties, though fortunately winds will likely be under warning threshold criteria. Minimal concerns Tuesday through Thursday as humidities increase. Humidities lower once again over our western counties Friday and next weekend. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...RUBIN LONG TERM...MAJ AVIATION...GCC FIRE WEATHER...RUBIN
Area Forecast Discussion
National Weather Service Goodland KS
625 PM MDT Sun Sep 2 2018 .UPDATE... Issued at 625 PM MDT Sun Sep 2 2018 Despite the moist, moderately unstable (1000-1500 J/kg mlcape), and uncapped airmass in place over the Tri-State area this afternoon -- scattered convection has largely been confined south/east of Goodland and, even there, coverage has decreased significantly between 22-00Z. The limiting factor this evening appears to be forcing. Regional radar trends and the latest HRRR simulated reflectivity guidance suggest little potential for convection over the Tri-State area for the remainder of this evening into tonight. The relative best potential for isold convection between 00-06Z will be in far eastern portions of the forecast area (Gove/Graham/Norton counties) -- in closer vicinity to outflow attendant widespread convection in central KS -- and where richer low-level moisture and near moist adiabatic mid-level lapse rates are more likely to foster/sustain additional updraft development. && .SHORT TERM...(This evening through Monday) Issued at 204 PM MDT Sun Sep 2 2018 Little has changed in the overall setup, with a broad trough over the central Rockies and embedded waves contributing to weak synoptic scale forcing. At the surface, front has stalled over the northwest corner of the forecast area with low level southeasterly flow advecting moisture into the area. Shear/instability parameters are best over the far eastern areas where there is a slight risk for severe storms capable of producing large hail/ damaging winds through the evening hours. In other areas, slow storm motions, the mean 0-6km wind is near zero, combined with the anomalously high moisture in place will result in localized heavy rainfall/flash flooding. Storm coverage/intensity will gradually diminish through the overnight hours. Areas of fog will develop towards sunrise as boundary layer cools/saturated, with fog gradually dissipating through Monday morning. On Monday, looks like more of the same with little change in the overall pattern. Southern areas again see the best combination of shear/instability so may see a severe storm or two there. Storm motions are higher compared to today, 0-6km mean winds actually increase to near 20kts by the afternoon, which may mitigate flash flooding concerns. Nonetheless, model QPF still showing some 1-2 inch bullseyes so cannot completely rule out the heavy rain/flash flooding threat on Monday. Temperatures will be slightly below normal due to persistent cloudiness. .LONG TERM...(Monday night through Sunday) Issued at 104 PM MDT Sun Sep 2 2018 An upper-level ridge will be centered over the Mid-Atlantic United States Monday evening while a broad upper-level trough will dip into the southwest United States. This will promote relatively strong south-southwesterly upper-level winds over the Central High Plains Monday through Wednesday. There is increasing confidence that this set up could lead to heavy rainfall and potentially flash flooding across the Tri-State area during this time period. Instead of a typical diurnal pattern of afternoon showers and thunderstorms, showers and thunderstorms will be possible essentially throughout the entire time period between Monday night and Wednesday night for most of the Tri-State Region. With measurable precip over the past couple days and more expected today, the ground will be relatively saturated when these potentially heavy rains come in the beginning of the coming week. This increases the confidence that flooding will be a concern in the next few days, especially in urban areas or eastern portions of the area where more rain has fallen during the Labor Day weekend. With a few days before the heaviest rainfall expected Tuesday evening and into Wednesday, there is still a lot of uncertainty about how much rainfall there will be and where that rainfall will be located. It appears likely that some locations will record up to an inch or more of rain Labor Day through Wednesday. Upper-level winds will begin to decrease in intensity towards the latter half of the coming week, but they will generally remain southerly or southwesterly until Friday evening when an upper-level trough will usher in weak northwest flow aloft over the Central High Plains. Scattered showers and thunderstorms will remain a possibility through early Friday. At this point, there is significant disagreement among model guidance about the chances for showers and thunderstorms next weekend. With the GFS keying in on an approaching strong longwave trough progressing eastward from the Pacific Northwest, vertical wind shear would increase and there would be some dynamic support for showers and thunderstorms late next weekend. However, the ECMWF model for example is less bullish on this approaching trough and would tend to keep the Central High Plains dry on Saturday and Sunday. For now, keeping a slight chance of showers and thunderstorms over eastern portions of our area for Sunday. High temperatures will start out in the upper 70s to low 80s Monday and Tuesday, before cooling off to the low 70s for Wednesday and Thursday after the heavy rains/abundant cloud cover expected on Tuesday and Wednesday. After that, highs slowly warm up to the mid 70s Friday and low 80s for the weekend. Similarly, low temperatures will be in the low 60s for Tuesday and Wednesday, then cool a little to the upper 50s for Thursday through the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 625 PM MDT Sun Sep 2 2018 VFR conditions will rule through this evening at both terminals. Fog and/or low stratus is expected to develop across portions of northwest KS and southwest NE overnight, with IFR/LIFR conditions possible between 09-13Z. At this time, the relative worst conditions are expected at the MCK terminal. Expect fog/stratus to lift/scatter to VFR by 15Z. Scattered thunderstorms may affect either terminal Monday aft/eve, though confidence in convective coverage/evolution remains too low to warrant explicit mention with the 00Z TAF issuance. E or SE winds ~10 knots will prevail this evening, followed by light/variable winds overnight, then SE/SSE winds at 10-15 knots Monday afternoon. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...VINCENT SHORT TERM...024 LONG TERM...PATTON AVIATION...VINCENT
Area Forecast Discussion
National Weather Service Lincoln IL
1048 PM CDT Sun Sep 2 2018 .UPDATE... Issued at 845 PM CDT Sun Sep 2 2018 The main area of convection remains anchored to our northwest this evening, although we have noticed a slight east movement in the convective band over the past couple of hours. The HRRR has been consistently weakening the southern portion of the complex thru late this evening and keeping the bulk of the activity to our north, with additional development taking place, possibly along the outflow boundary across our north late tonight which may tend to increase the coverage over the far northern areas. Otherwise, the rest of the forecast area should stay away from the rain and remain warm and humid overnight with early morning lows holding in the low to mid 70s. The upper level ridge to our east at 500 mb is forecast to push a bit further west into the Midwest on Monday which would keep any convection widely scattered during the day. Several weak shortwaves seen on the water vapor loop this evening to our southwest which are forecast to track northeast along the western periphey of the ridge and affect mainly west central and central Illinois on Monday. This will result in a continuation of the low POPs (isolated to widely scattered thunderstorms), especially during afternoon and early evening hours. Another hot day again across the region with afternoon temperatures well above normal for the first week of September with highs in the upper 80s to lower 90s, and heat index values in the mid to upper 90s. Only minor adjustments made to POPs across the forecast area for tonight along with some tweaks to the evening temperatures in the grids, otherwise, the rest of the forecast is in good shape. No ZFP update needed at this time. && .SHORT TERM...(This evening through Monday) ISSUED AT 305 PM CDT Sun Sep 2 2018 The forecast remains hot and humid with periodic chances for showers and thunderstorms to wrap up the holiday weekend. Overall, the forecast area is trapped between a more progressive southwesterly flow from a general trough at 500mb over the western half of the CONUS... and an upper ridge over the southeast. The rest of the forecast relies on the interaction between the two to drive the local weather...as well as the interaction with a weak tropical system moving moisture into the region for the latter half of the week. Continued southerly flow at the surface further reinforcing the warm temps streaming into the midlevels. Temps definitely on the warmer side of guidance through today. With continuity in mind, have gone more diffuse with the pops for tomorrow, with a diurnal assist with heat of the day. Best chances for impact may be NW of the IL River Valley with the more active southwesterly flow, general airmass showers/TS still cropping up with the unstable airmass. Overnight lows today, once again, not dropping far, into the low to mid 70s. Tomorrow a very similar day to today...hot, humid, increasing clouds translating into afternoon chances for showers/thunderstorms. .LONG TERM...(Monday night through Sunday) ISSUED AT 305 PM CDT Sun Sep 2 2018 Models still having some issue with the showers to the NW and how far they creep while the upper ridge strengthens and pivots the flow aloft to a more longitudinal direction by midweek. Low chance pops are all over the place beyond midweek, reflecting the uncertainty, as well as the general unstable airmass in the afternoons. Furthermore, the development of a tropical system in the Gulf pushing into the ridge may further complicate the extended, as moisture is pulled into the Miss River Valley from that system. Until the pattern evolves later in the week, the region will not get out of the hot/humid/chance thunderstorms regime. After midweek, the forecast is starting to morph with both the influence of the Gulf system moving onshore, as well as another trough moving across southern Canada, and potentially trying to dislodge the hot airmass in place. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1045 PM CDT Sun Sep 2 2018 VFR conditions are expected this forecast period. The large area of convection that occurred to our west and northwest into early this evening produced an outflow boundary which has pushed south and east of GBG late this evening. Isolated showers and storms were trying to develop ahead of this wind shift line but are struggling due to poor mid level lapse rates. Will keep an eye on the progress of the development and may need to add VCTS to PIA but will make that a last minute decision. Otherwise, little change from previous thinking with quite a bit of cirrus moving in from the west from the weakening storms, which looks to affect mainly PIA and BMI. Forecast soundings indicate quite a bit of cumulus will once again develop by early Monday afternoon, which may lead to a widely scattered TSRA but where that may occur is a low probability occurrence this far out in the forecast period, so will hold off including in this set of TAFs. Light southerly flow tonight at 10 kts or less, will increase out of the south on Monday to 10 to 15 kts with a few gusts up to 20 kts possible in the afternoon, before diminishing to 10 kts or less by 00z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Smith SHORT TERM...HJS LONG TERM...HJS AVIATION...Smith
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
1104 PM CDT Sun Sep 2 2018 .SYNOPSIS... Issued at 312 PM CDT Sun Sep 2 2018 A stagnant H5 pattern remained in place across the lower 48 this morning. High pressure was located over sern Virginia. HT rises in association with the high were relatively minor this morning with rises on the order of 10 to 30 GPM. Those Ht rises were focused across the mid atlantic states. Further west, a broad trough of low pressure extended from a closed low in Saskatchewan, south into the swrn CONUS. East of this trough, swrly flow aloft was present from the swrn CONUS to the central and srn Plains. Within this swrly flow, a shortwave was noted across western Kansas and it has since moved into swrn Nebraska per WV imagery. Some light precipitation was occurring during the late morning hours across far southeastern areas of the forecast area. Elsewhere, skies were partly to mostly cloudy and 3 PM CDT temperatures ranged from 72 at Gordon to 84 at North Platte. && .UPDATE... Issued at 741 PM CDT Sun Sep 2 2018 Just an isolated rain chance overnight and Monday morning according to a blend of the HRRR, RAP, HREF and model consensus. Rain chances should increase Monday afternoon. A new forecast is in place for the rain chances and fog overnight and Monday. UPDATE Issued at 635 PM CDT Sun Sep 2 2018 The model consensus is showing a strong signal for very low ceilings and fog Monday morning, mainly across the higher elevations of the Sandhills and southwest Nebraska. A new forecast is in place for areas of fog late tonight and Sunday morning. && .SHORT TERM...(This evening through Monday) Issued at 312 PM CDT Sun Sep 2 2018 Tonight and Monday...Precipitation chances are the main forecast challenge over the next 24 hours. For Tonight: Another round of showers and embedded thunderstorms, some with heavy rain will cross the Central Plains tonight. The latest GFS, NAM12 and HRRR solutions have the best forcing just off to the south and southeast of the forecast area tonight. The WARW soln however, does develop some precipitation along the the surface boundary, which currently extends from far swrn Nebraska, into central and the far northeastern portion of the forecast area. That being said, with the surface boundary in play and weak forcing INOVF the boundary, did not totally eliminate pops from the fcst tonight in the southern and eastern portion of the forecast area. Elsewhere, scaled back pops or eliminated them all together in the west and northern forecast area as forcing is limited, along with the entrainment of drier air from across the border in South Dakota. On Monday, a second round of precipitation will begin to push into southwestern then central Nebraska late in the day. The latest NAM12 and GFS solutions lift some decent forcing across central Colorado, which then approaches northeastern Colorado and swrn Nebraska late in the day. With good agreement between the NAM12 and GFS solutions, as well as support from the WARW, decided to increase precipitation chances from swrn into central and north central Nebraska for Monday afternoon/Monday night. Right now, the threat for severe storms appears fairly low, with the main threat being heavy rain. Looking at fcst PWATS for tomorrow afternoon they are running 1.0 to 1.5 inches, so localized heavy rain is possible and will continue to mention the threat in the HWO. .LONG TERM...(Monday night through Sunday) Issued at 312 PM CDT Sun Sep 2 2018 High pressure aloft will remain anchored across the Mid Atlantic through Thursday. This will place the forecast area in west southwesterly flow aloft through mid week. This along with abundant low level moisture, will be favorable for off and on rain for the bulk of the upcoming week. Confidence in drier conditions really doesn`t materialize until after Friday as the high finally breaks down in the east. A midlevel trough of low pressure, will track through the Central Plains Saturday, forcing much drier air into western and north central Nebraska late Saturday into Sunday. In the meantime, precipitation chances will be fairly high and temperatures at or slightly below normal for the week. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1104 PM CDT Sun Sep 2 2018 The model consensus continues to show a strong signal for very low ceilings and fog Monday morning, mainly across the Panhandle, the Sandhills and southwest Nebraska. IFR/LIFR in fog and very low ceilings is expected 09z-15z Monday. MVFR/IFR ceilings are expected 16z-22z Monday across areas along and east of highway 83. VFR is expected elsewhere. Isolated showers and thunderstorms are expected overnight until 21z Monday. Scattered showers and thunderstorms are possible after 21z Monday, mainly across swrn and ncntl Nebraska. Thunderstorm chances are expected to increase Monday evening with the approach of an upper level disturbance, currently across New Mexico. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...CDC SYNOPSIS...Buttler SHORT TERM...Buttler LONG TERM...Buttler AVIATION...CDC
Area Forecast Discussion
National Weather Service Lake Charles LA
801 PM CDT Sun Sep 2 2018 .UPDATE...A flash flood risk remains in area this evening, even though the overall convective structure has decayed. A nocturnal flare up is expected later tonight into early Monday which may result in high rainfall rates and totals. The main focus is expected to be generally west of a DeRidder to Pecan Island line. The hi-ress HRRR depicts a wide swath of greater than 2 inches with some totals over 8" for multiple runs and for this reason WPC has upped the risk to moderate for tonight/early Monday. Rainfall totals in the FAA have been upped to reflect this, however the areal/spatial coverage of the watch has not changed. && .PREV DISCUSSION... /issued 644 PM CDT Sun Sep 2 2018/ DISCUSSION... For the 03/00Z TAF Issuance. AVIATION... A mid/upper level swirl noted along the coast near the Texas/Louisiana border will slowly move west into Southeast Texas tonight into early Monday. Plenty of tropical moisture is noted with this feature. As is typical for these systems, beginning to see a slow decrease in shower activity this evening through about 03/03Z. Then nocturnal shower activity will again re-developed and become more focused near the center during the overnight. Therefore, prevailing shower activity is expected to move back into the KBPT/KLCH by 03/08Z and continue through 03/18Z. Shower activity will develop at other sites with daytime heating between 03/12Z and 03/18Z. Mainly MVFR conditions are expected, however, occasional IFR to LIFR will be possible in the stronger showers. Rua PREV DISCUSSION... /issued 400 PM CDT Sun Sep 2 2018/ DISCUSSION... Water vapor/88D imagery show mid/upper-level low spinning over the coastal waters just south of Jefferson County this afternoon, while sfc analysis shows a coastal trof in place from the middle TX coast newd. Combo of these features in a very moisture-rich airmass is producing, as expected, widespread showers with scattered storms across the entire region. Latest scan of hourly rates shows heaviest rains likely only producing amounts around 1 inch/hour and this has been the trend for much of the day. On the plus side, much of the area has remained in the 70s under dense cloud cover and precipitation. Needless to say, a messy forecast today. In the short-term, will continue to see widespread showers/few storms through the remainder of the afternoon and past sunset as the mid/upper low continues its slow wwd trek. High res guidance is indicating a marked increase in precip again later tonight, mainly over sern TX. As we move through Labor Day, the low is progged to open up as it gets pulled into the wswrly flow aloft, ejecting enewd... leaving the area in a weakness aloft. A continued deep srly flow will maintain a very moisture-rich airmass with forecast soundings indicating PWAT values remaining well above 2.0 inches. Therefore very elevated POPs remain in the forecast for tomorrow, with best QPFs lingering across the wrn portions of the forecast area. As far as flood watches go, here is the current plan for the WFO LCH CWA...we will be maintaining the current Flash Flood Watch for Acadiana and portions of swrn LA through its scheduled expiration time of 00z/19CDT. Shortly thereafter, we will likely be issuing a new Flash Flood Watch, this time for all of sern TX plus the swrn 1/2 of our LA zones (essentially Beauregard to Jeff Davis to Vermilion) which will run until 00z tomorrow evening. Mean areal QPFs of around 4 inches are noted for coastal sern TX, then tapering downward as you head ewd. Of course likely higher amounts are expected. Next up...newly minted Potential Tropical Cyclone #7 off the sern coast of FL is forecast to continue moving nwwd while steadily strengthening as it moves into the ern Gulf. Latest track guidance indicates this system moving ashore near the mouth of the MS River early Wednesday as a strong tropical storm (named Gordon). On this track, the primary impacts for our forecast area would be another round of elevated rain chances, with highest POPs over the Atchafalaya Basin, starting Tuesday and lingering through mid-week as the system continues nwwd across the MS Delta and into nwrn LA. Current mean QPFs show the potential for another 1-2 inches across the ern 1/2 of the area, but obviously this will be tweaked as we move closer to the event. Things don`t look to improve much once Gordon departs the region as the area remains under a weakness aloft...combined with continued copious moisture, expect elevated rain chances to linger right on through the end of the forecast period. MARINE... For now, no headlines are included on the coastal waters as progged wind speeds remain below 20 knots. Will have to monitor over the next day or so to see how wave height forecasts go for swell purposes. CLIMATE... A quick recap of some climatological Summer (June through August) statistics. Lake Charles (records date back to 1895) -3rd warmest Summer (84.3 degrees - record: 85.3/2011) Lafayette (records date back to 1893) -6th warmest Summer (83.6 degrees - record: 85.2/2011) New Iberia (records date back to 1948) -7th warmest (tie) Summer (83.0 degrees - record: 84.9/2011) Beaumont/Port Arthur (records date back to 1901) -8th wettest Summer (26.14 inches - record: 71.42/2017) -10th warmest (tie) Summer (84.3 degrees - record: 86.3/1902) Alexandria (records date back to 1892) -finished just outside the top ten warmest Summers && .PRELIMINARY POINT TEMPS/POPS... AEX 72 88 71 90 / 40 60 20 30 LCH 74 84 74 87 / 70 80 30 50 LFT 74 87 74 89 / 50 60 20 50 BPT 77 84 76 86 / 80 80 40 50 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...Flash Flood Watch through Monday evening for LAZ030-041-042-052- 073-074. TX...Flash Flood Watch through Monday evening for TXZ180-201-215-216- 259>262. GM...None. && $$ PUBLIC...05
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
847 PM CDT Sun Sep 2 2018 .UPDATE... 847 PM CDT Evening Update... Locally heavy rainfall threat remains across far northern IL this evening/overnight, while severe thunderstorm threat diminishes. No changes planned to flash flood watch extent at this time. Linear complex of thunderstorms stretches from the Quad Cities to far southeast WI per regional radar at mid-evening. LOT 88-D depicts an outflow boundary which has surged east-southeast from these storms, slowing their eastward progress, with a weaker and largely elevated nature to convection than had occurred to our northwest earlier this afternoon/evening. Despite RAP analysis of 2000 J/kg of MLCAPE ahead of this complex of storms, the advancing outflow boundary, decreasing deep layer shear to the east/southeast and a slowly cooling nocturnal boundary layer will likely limit the potential for localized severe wind gusts with these storms. Locally heavy rainfall amounts are thus the primary concern with these storms through late evening, as they remain organized in a southeast to northeast fashion parallel to the low- mid level wind field. With storms currently across portions of north central IL which saw heavy rainfall last night, and early Friday, will have to watch for any additional flood concerns. Dual-Pol data suggests weaker convective elements have resulted in a decrease in instantaneous rainfall rates over the past 1-2 hours, though slow movement of line will maintain potential for training across portions of the area. Had issued a flood advisory for this area earlier as convection moved in, though will continue to monitor trends over next few hours in case upgrade to flash flood warning headlines become necessary for a smaller portion of the advisory area. High-res guidance indicates an overall weakening trend to storms over the next few hours, though with focus for additional development remaining over the northwest half of the cwa into the overnight hours. Ratzer && .SHORT TERM... 230 PM CDT Through Tonight... The main concern will once again be heavy rainfall potential across north/northwest portions of the forecast area. Not much has changed synoptically from yesterday with a large high parked over the eastern half of the country with a cutoff upper trough over the west and active flow across Canada and the northern Plains. The area has become quite unstable but there is little in the way of forcing currently overhead aside from some weak forcing lifting northward into the southern CWA. Have seen a few showers pop up down towards Kankakee but with fairly week deep layer shear these have not been able to maintain themselves. Larger scale forcing is to the west across Iowa and moving toward the northwest section of the forecast area. Thus expect northwest areas to see better development of isolated to scattered showers and thunderstorms through the afternoon, though something may pop op elsewhere in the forecast area. The impulse from Iowa will draw nearer this evening and expect that there will be much higher coverage of showers and thunderstorms, this evening and into the early overnight hours over the northern and western forecast area. Expect a more southwest to northeast orientation of storms, at least initially, but this may become more west to east with time. Training cells with very heavy rainfall are expected once again and will issue a Flash Flood Watch for Ogle, Winnebago, Boone, McHenry and Lake Counties for this evening and overnight. Many of these areas received 3 to 5 or more inches of rain yesterday and last night. Am a little less confident in the eastern extent of the watch as the more persistent activity may be just to the west but given earlier rainfall and higher degree of urban landscape opted to include these areas in the watch. Any storm may bring very high rainfall rates and training of cells would bring the potential for several inches of rain where it persists. Will also need to monitor severe potential though lower end deep layer shear may be a limiting factor, though downdraft CAPE values are increasing. Damaging wind gusts would be the main severe threat with a lesser hail threat given the warm atmosphere but strong instability. May see some of the shower and thunderstorm activity spread south and east late tonight but am not terribly confident in this occurring. MDB && .LONG TERM... 230 PM CDT Monday through Sunday... An active period of weather looks to continue over portions of northern Illinois and northwest Indiana through the upcoming week. Northern Illinois and northwest Indiana will remain hot and humid through midweek with periodic precip chances as we remain on the periphery of a strong upper ridge centered over the mid Atlantic Coast. Quasi-stationary boundary that has been over the area a couple days now is forecast to be in the vicinity of far northern Illinois once again on Monday, serving as the focus for the greatest thunderstorm potential. Farther south, expect a mix of sun and clouds in the warm sector, but otherwise hot and humid conditions with temperatures pushing into the upper 80s to near the 90 mark. Low to mid 70 dew points will persist resulting in heat indices in the mid to upper 90s. Guidance indicates the jet will shift north to northern Wisconsin which leaves sub-marginal deep layer shear locally. Depending on how much diabatic heating occurs given the usual limiting factors of convective debris and cloudiness, it`s still possible that we see moderately strong instability develop during the afternoon which would support at least a localized severe threat. The ECMWF continues to have a good signal for dry weather on Tuesday as the upper ridge axis retrogrades slightly towards the Appalachians and precip chances shift farther north and west as a result. Meanwhile, the GFS is indicating its typical broad-brushed afternoon convection despite showing the best forcing to our west and north. Favoring the dry European solution for Tuesday, which given the closer proximity to the upper ridge and lower precip chances/cloud cover should present the best chance for some more widespread 90 degree temps over the CWA with resulting heat indices near 100F. Pattern is expected to become slightly more progressive by Wednesday as strong vort moves east across Canada and upper ridge axis gets nudged back east. Stalled frontal boundary over MN/WI should start to sag back south again Wednesday with precip chances returning locally. Strong surface ridge building across the Upper Midwest will help to drive some cooler air into the Great Lakes with baroclinic zone stalling over the region through the remainder of the week. The end result will be a decent north/south temperature gradient over the CWA from Thursday into next weekend with additional precip chances in the vicinity of the baroclinic zone. Deubelbeiss && .AVIATION... For the 00Z TAFs... 645 pm...Two primary forecast concerns are thunderstorm chances through the period and wind directions Monday. Isolated showers developed across the Chicago terminals earlier this afternoon and are lifting northeast. Trends would support mainly dry conditions for the Chicago terminals for the next few hours. Focus is for a line of thunderstorms from eastern IA into southern WI which will slowly sag into the rfd area in the next few hours. This line is expected to remain northwest of dpa/ord into this evening. Additional thunderstorms are expected in this same area later this evening into the overnight hours. Its possible that some of this later activity moves toward the Chicago terminals Monday morning...perhaps after sunrise. Confidence is too low for any mention during this time period. All of this convection is likely to push some larger outflow boundary south into northern IL by Monday morning making for a difficult wind forecast. Southerly winds are likely to continue this evening with some type of shift east or northeast by morning. Wind directions may be quite variable depending on this outflow...where it moves and any ongoing convection. Whether from this boundary or with a traditional lake breeze...easterly winds are then expected at the Chicago terminals by mid/late Monday afternoon. Changes to the wind forecast can be expected with later updates. This boundary or other outflows from morning convection will likely allow new thunderstorm development Monday afternoon. While the current Chicago area tafs are dry...the best timing for any additional thunderstorms appears to be Monday afternoon. Thus... later tafs may need thunder mention for Monday afternoon. Mvfr cigs are possible toward morning and then through late Monday morning before lifting to a low vfr deck. Maintained scattered mention as confidence remains low. cms && .MARINE... 230 PM CDT Low pressure will move east across the Great Lakes through Monday while a cold front sags south across Lake Michigan through the day Sunday. Fresh south breeze will prevail out ahead of the front for today and tonight, then expect winds to veer to the northeast and east behind the weak front on Monday. Another low is expected to lift from the central Great Plains Tuesday to northern Lake Michigan Tuesday night. Fresh to strong southerly breeze is expected ahead of the front through the day Tuesday. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...Flash Flood Watch...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008 until 7 AM Monday. 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 Pueblo CO
259 PM MDT Sun Sep 2 2018 .SHORT TERM...(This evening through Monday) Issued at 256 PM MDT Sun Sep 2 2018 Currently... Showers and a few thunderstorms were noted over the higher elevations of the forecast area at 2 pm. Over the valleys and plains, mainly variable high cloudiness was noted. Radar indicated an MCV feature was still spinning over NC Pueblo/SC El Paso county. Dwpts across the region were around 60 along the KS/CO border/50s across most of the plains and 30s and 40s in the valleys. SPC meso page shows about 1000 J/kg of cape was advecting into the Pikes Peak region from the northeast. CAPE values of 500-1000 were noted over most of the SE Plains. Bulk Shear was modest along the CO/NM border with values approaching 40 knots. This shear was associated with a jet pushing across the s tier. Rest of Today into Tonight... HRRR has been persistent all day showing showers and storms initiating along the I-25 corridor, and see no reason to believe this will not happen. MCV over Pueblo/EL Paso county will likely be the initiating point in an hour or so. Higher CAPE advecting towards this feature should allow for sufficient juice to keep storms going once they develop. Given that the better shear is farther south, storm intensity should remain below severe limits although gusty winds will be possible. As afternoon progresses into early evening, expect more storms to fire along the entire corridor. Radar has shown storms moving towards the west all day. Believe this may change a bit as storms become deeper, and outflow may allow them to propagate slowly eastward later this evening. Storms over the far eastern plans may be few and far between early this evening but should pick up later this evening. Short range guidance shows that another mid level circulation is likely to develop around the Trinidad/Walsenburg region later this evening and move slowly north. This will help deepen the easterly flow over north of the low. This should keep showers and storms going on the plains, especially in the greater Pueblo/Pikes peak region through the nighttime hours. For this reason, kept rather high pops over parts of the region throughout the night. Without saying. most of the night will remain cloudy over the fcst area. Given the moist flow over the area and the circulations in the area, some localized heavy rain will be possible, and burn scar flooding will be possible. Tomorrow... Circulation will lift into NE CO tomorrow. Guidance products show modest drying as flow becomes WSW throughout a good part of the column over most of the area by tomorrow afternoon. This should limit the amount of precip over the region, with the overall best chance of precip over the higher terrain tomorrow. Area will still be in cyclonic flow aloft so this should keep a bit of synoptic lift over the fcst area. far east plains during the afternoon may also see a bit better chance of precip as compared to the rest of the plains. Temps tomorrow will be a bit cooler than today with highs in the 70s to L80s plains and 60s and 70s valleys. .LONG TERM...(Monday night through Sunday) Issued at 256 PM MDT Sun Sep 2 2018 Unsettled weather will continue Monday night into the middle of the week with southwesterly flow aloft continuing to bring a series of weak disturbances across southeast Colorado. Abundant moisture and the weak disturbances will combine to produce showers and thunderstorms across much of the forecast area. The primary concerns with any thunderstorms will be locally heavy rainfall which could cause problems for area burn scars, but severe weather appears unlikely. A cold front moves south through the eastern plains, bringing cooler temperatures Wednesday and Thursday. Expect highs to be in the 70s at the lower elevations both Wednesday and Thursday. The chance for showers and thunderstorms will continue each afternoon and evening through about Thursday. By Friday, the upper level ridge axis begins spread across the four corners region and into Colorado. The moisture plume shifts eastward and drier and warmer conditions will be on the way for Friday, Saturday and Sunday. Expect highs to warm from the upper 70s and 80s Friday on the plains to the 80s and around 90 degrees on the plains by Sunday afternoon. Stark && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 256 PM MDT Sun Sep 2 2018 Lots of clouds will be over the region, especially tonight and into tomorrow morning. A Monsoon disturbance will move across the region tonite and this will likely keep showers going through the nighttime hours, especially at KCOS. Main concern is how low cigs will get at KCOS and KPUB, and this will be dependent on how saturated we can get the lower atmosphere. Best chance for lower cigs will be up at KCOS, and these lower cigs/showers may last into mid morning. By tomorrow afternoon, VFR conditions anticipated across the entire region. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HODANISH LONG TERM...STARK AVIATION...HODANISH
Area Forecast Discussion
National Weather Service Tulsa OK
938 PM CDT Sun Sep 2 2018 .DISCUSSION... Much of the scattered convection that developed across the area this afternoon has dissipated this evening. Some activity continues across south central Kansas and central Arkansas. Available guidance suggests that it is not out of the question for a few showers to redevelop overnight in our area, and thus, we see no reason to remove the slight chance POPs in the ongoing forecast. Temperature trends seem reasonable as well. Latest HRRR and NAM continue to spread low clouds into srn areas late tonight and then northward Monday morning. Have made slight adjustments to sky trends to reflect a later arrival of low clouds. Latest data continues to support an increasing coverage of showers and thunderstorms Monday/Monday night as precipitable water increases to about 2.0" during this period (near the max average for this time of year) and upper low over sern TX approaches. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ SHORT TERM...69
Area Forecast Discussion
National Weather Service Tucson AZ
305 PM MST Sun Sep 2 2018 .SYNOPSIS...Scattered thunderstorms mainly from Tucson eastward through Labor Day. A slightly drier regime occurs Tuesday into Friday with isolated thunderstorms mainly near the New Mexico border. High temperatures will be a few degrees below normal through Wednesday, warming to near normal Thursday into next weekend. && .DISCUSSION...Satellite imagery this afternoon showed partly cloudy skies across much of southeast Arizona. A few showers and thunderstorms had also developed mainly east of a line from about Gila Bend to Sierra Vista. Surface temperatures ranged from the low 90s around Tucson to the mid 70s across Cochise County where cloud cover has limited the extent of heating so far today. The pattern was defined by an upper trough draped across the southwestern states, which is progged by various NWP models to deepen slightly as it pushes very slowly eastward into NM over the next few days. As such, additional dynamics for storm development will be in place today into Labor Day, with isolated to scattered showers and storms in the forecast into tomorrow evening. In the near term, this thinking was consistent with the latest solutions from the HRRR, U of A and other local WRFs. The best chance for measurable rainfall at KTUS is thought to be this afternoon or this evening as suggested by the 02/20Z HRRR and 02/12Z U of A WRFNAM. However, the continued robust westerly flow will work to push deeper moisture eastward by Tuesday, confining convection to areas mainly east and south of Tucson, and especially near the AZ/NM border. This trend is expected to continue through Friday, when the trough finally moves out and high pressure off the southwest coast of California advances eastward. This will draw drier air into the state on northerly flow aloft. There will still be some low level moisture capable of supporting a few buildups, but activity should by and large be limited this weekend. High temperatures through Wednesday will be 3-5 degrees below average. An increase in heights will then warm temperatures to within a degree of average Thursday into next weekend. && .AVIATION...Valid through 04/00Z. Scattered -TSRA/-SHRA mainly from KTUS vicinity eastward to the New Mexico state line into Monday morning. Cloud decks from KTUS eastward 8-12k ft AGL along with SCT-BKN clouds AOA 20k ft AGL. West of KTUS, FEW-SCT clouds around 10k ft AGL. SELY/SWLY SFC wind generally less than 12 kts, except gusts up to 40 kts near stronger TSRA. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered thunderstorms mainly from Tucson eastward to the New Mexico state line through Monday. A drying trend will then occur Tuesday into next weekend, with only isolated afternoon and evening thunderstorms east of Tucson. Expect terrain driven 20- foot winds at less than 15 mph, with brief strong gusts possible near thunderstorms. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Carpenter/Pegram Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson