Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/27/20

Area Forecast Discussion
National Weather Service Amarillo TX
628 PM CDT Sun Jul 26 2020 .AVIATION... Several areas of cumulus development this afternoon in response to afternoon heating and dewpoints in the upper 50s. Most of the clouds are struggling to break through the cap, which mesoscale models suggest are around 7 degrees C around 10Kft. The cap is a bit weaker to the far northwest, and that is where we see some convective showers beginning to develop near the TX/NM state line just south of Clayton. Given the cap strength, would expect the storms today to be quite confined to the north and northwest until a front or other lifting mechanism is present. The lifting mechanism will be the awaited cold front, currently expected into the area early Monday. At 23Z, the cold front is located in northwest Kansas / northeast Colorado and will be making slow and steady progress through the evening. By mid morning, between 12Z and 18Z Monday, there will be enough showers or thunderstorms around to warrant at least Prob30 groups within each terminal forecast. Thunderstorm chances will become a bit more widespread during the day on Monday, and are expected to last into Monday night and even Tuesday. For the short term, flying conditions will be decent for the next six to 12 hours, before deteriorating conditions after that. Fox && .PREV DISCUSSION... /Issued 408 PM CDT Sun Jul 26 2020/ SHORT TERM...Tonight through Monday Night... Difficult forecast over the next 24-48 hours. Visible satellite this afternoon shows quite a bit of cloud cover over the area with cumulus filling in everywhere. We already have some pop up showers over eastern Oldham/western Potter Counties. The HRRR has been on it lately and picking up on these little pop up showers. Expect more to pop up by 3pm through the central Panhandles and die off around 6-7pm. Satellite is also showing the thicker cloud cover over New Mexico associated with the tropical moisture from Hanna as it is circulated around the mid-level high pressure over the eastern Panhandles/western OK. The tropical moisture will continue filling into the area and interact with disturbances rotating around the high pressure, the mountains in New Mexico, and a cold front that is progged to push into the area tonight. All these features will create repeated rounds of precip for on and off showers. We have already seen the need for several issuances of flooding products over the last few weeks due to the rain rates with the pop up showers, so with the PWATs running extra high and near record with the tropical moisture, wouldn`t be surprised for the showers to produce significant rain rates to cause flooding issues. The front will add extra lift and any mid-level disturbances will be an added bonus to create enhancements to the precip. The difficult part of the forecast is what to do with the front and the location of these enhancements. The models want to hang the front in the middle of the Panhandles. Feel the cold pool with the storms will likely move the front further south and not hang it up, so tried to progress the pops Monday afternoon. The position of the front and other mesoscale features such as how the Canadian River Valley or being off the Caprock will play a roll in where the higher precip totals will be. May need to do significant updates depending on how the front plays out. Believe no matter how the front moves, there is going to be quite a bit of precip with significant enough rain rates that a Flash Flood Watch is warranted for tomorrow afternoon through the night. Beat LONG TERM...Tuesday through Sunday. For Tuesday and Tuesday night, plenty of moisture should continue to reside over the forecast area. The upper level ridge of high pressure will remain over the southwest states, placing our region in west northwest flow aloft. A minor upper level shortwave trof embedded in the flow pattern is progged to translate east across the area Tuesday and Tuesday night, and should lead to another round of showers and tstms. Highest pops were placed across the far northwest sections with lowest values in the far southeast Texas Panhandle during this time period. Residual showers and tstms with far less coverage is anticipated Wednesday and Wednesday night as the aforementioned minor upper level shortwave trof moves east of the region. For Thursday through Sunday, the upper level ridge of high pressure is forecast to meander around the four corners region during this time frame as seen in latest medium range models. At the same time, an upper level trof of low pressure is progged to develop over the eastern states. This is a continuation of the northwest flow aloft, with a threat for late afternoon and nighttime showers and thunderstorms Thursday through Sunday. The NBM pops during this time period look reasonable and were utilized, with a slight edge upward Thursday night as values looked a bit low given the expected pattern. 02 && .AMA Watches/Warnings/Advisories... TX...Flash Flood Watch from Monday afternoon through Tuesday morning for the following zones: Armstrong...Carson... Collingsworth...Dallam...Deaf Smith...Donley...Gray... Hansford...Hartley...Hemphill...Hutchinson...Lipscomb... Moore...Ochiltree...Oldham...Palo Duro Canyon...Potter... Randall...Roberts...Sherman...Wheeler. OK...Flash Flood Watch from Monday afternoon through Tuesday morning for the following zones: Beaver...Cimarron...Texas. && $$ 14/11
Area Forecast Discussion
National Weather Service La Crosse WI
632 PM CDT Sun Jul 26 2020 .SHORT TERM...(This evening through Monday) Issued at 154 PM CDT Sun Jul 26 2020 Surface analysis at 1 pm has a cold front sagging southeast, currently extending from central WI into northeast IA. Radar pretty quiet right now but expecting a broken line of showers/storms to form along the cold front as it progresses southeast through the rest of the area. So, storms this afternoon into this evening look to be confines mainly south of a Richland Center/Boscobel WI to Elkader IA line. MLCape is around 2000J/kg range now and expected to top off in the 2000-3000j/kg as the front pushes through. Bulk shear fairly modest with RAP effective bulk shear around 20kt. So, not expecting much for severe weather but could see a few stronger storms with higher wind gusts and very heavy downpours given very warm/humid airmass. Front and associated storms expected to push south of the area this evening as refreshing Canadian high pressure pushes in. Cooler/much drier airmass over the area through Monday with northwest winds in the the 10 to 20 mph range. Look for highs Monday in the upper 70s to lower 80s with dewpoints in the mid-50s to near 60...ahh! .LONG TERM...(Monday night through Sunday) Issued at 154 PM CDT Sun Jul 26 2020 For those that did not get some rain this weekend, the prospects are not looking good over the upcoming week. The upper level low currently over central Manitoba will track slowly to the east allowing the upper level ridge to build back over the northern Rockies into the High Plains. This looks to leave the Upper Midwest under a relatively quiet northwest flow. What little rain chances there will be are centered on Thursday and Saturday. A weak short wave trough may pass across the Great Lakes region Thursday with the 26.12Z GFS showing a little bit of rain along a weak cold front coming through with the short wave trough. The 26.12Z ECMWF is farther to the southwest with the short wave trough which keeps the rain farther to the southwest as well. By Saturday, another weak short wave trough and cold front look to pass across the region. Again, some differences between the models on the placement of the short wave trough and how much rain may occur across the area. With the northwest flow aloft, there does not look to be any big warmups coming in the next few days. Look for daytime highs to generally be in the upper 70s into the 80s with overnight lows mainly in the 50s to lower 60s. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 622 PM CDT Sun Jul 26 2020 The bulk of the storms have pushed off to the southeast and winds turned to the northwest at 6 to 12kts. The cold front could increase winds for an hour or so with some high gusts to around 15 to 20kts. Any showers/storms will be isolated with the cold front and mvfr conditions patchy ahead of the front. Continued deepening of the mid-level trough Monday and very steep lapse rates favor mixing with northwest wind increasing to 12kts gust to 24kts. Some sct-bkn cumulus fl050-060 and pop-up showers possible 20-24Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...Heat Advisory until 7 PM CDT this evening for WIZ054-055-061. MN...None. IA...Heat Advisory until 7 PM CDT this evening for IAZ010-011-029-030. && $$ SHORT TERM...DAS LONG TERM...04 AVIATION...Zapotocny
Area Forecast Discussion
National Weather Service Denver/Boulder CO
740 PM MDT Sun Jul 26 2020 .UPDATE... Issued at 732 PM MDT Sun Jul 26 2020 Most of the shower and thunderstorms activity has been confined to the southern third of the forecast area, primarily south of Interstate 70. Have dropped the pops to mainly isolated coverage north of the interstate, with mainly scattered coverage to the south. Latest HRRR shows an increase in showers over the northeast corner of the state late tonight so will keep pops going there. Have also added fog to the northeast plains after 3 am. && .SHORT TERM...(This evening through Monday) Issued at 321 PM MDT Sun Jul 26 2020 Shower activity over the forecast area has been increasing over the past couple hours with the heaviest showers up to this point over Park and Lincoln Counties. The surface cold front has moved over the Palmer Divide and will become a focus for additional shower development through this evening. The airmass remains very moist with precipitable waters above 1 inch and surface dew points in the upper 50s to mid 60s. Locally heavy rain will be possible with showers that develop over the frontal boundary. one to two inch amounts over one to two hour periods will be possible. Antecedent conditions should be dry enough to handle the rainfall, so no Flash Flood watches at this point. Local advisories or warnings may be necessary if evening thunderstorms stall. Shower activity should be on the decrease after midnight. Later tonight, continuing moist upslope winds will produce areas of stratus and fog in the South Platte River Valley. Later tomorrow, moisture is expected to linger over the mountains and Palmer Divide, but some drying and cooling is expected over the northeast plains as weak northeasterly flow continues in the wake of today`s frontal passage. As temperatures remain the upper 70s and lower 80s, the airmass will be too stable for very much shower development. .LONG TERM...(Monday night through Sunday) Issued at 321 PM MDT Sun Jul 26 2020 Lingering showers and tstms Mon night will be mainly focused over the higher terrain along and south of I-70. This activity will end by midnight. Looking ahead to Tue, an upper level trough will move across the area. This feature has fairly decent mid level ascent, with it, for this time of the year. As a result, expect widespread showers and storms over the higher terrain with activity spreading across the plains in the aftn and evening hours. MLCAPE over the plains is in the 500-1000 j/kg range and with increasing shear, late in the day, could see some stronger storms. As for highs, readings will be in the 80s over nern CO. For Tue night into Wed, the upper level trough will eventually develop into a closed low over Wyoming. Cross-sections show decreasing moisture over the higher terrain so only expect isold to widely sct tstms. Over nern CO, a lee trough will be over the plains with decent instability over the far nern plains. So this area will probably have the best chc of tstms. As for highs, readings will range from the mid 80s to lower 90s across the plains. By Thu, the upper low will move southeast into Nebraska, with rather stg subsidence over the area. Cross-sections show some moisture mainly over the far ern plains. Not sure why blended solution is showing chc pops over the higher terrain based on current data. Meanwhile, depending on the position of the upper level low, there could be some threat of showers and storms over the far ern plains. As for highs, a front may affect nern CO which would keep highs mainly in the 80s. Looking ahead to Fri, the upper level low will continue to move slowly southeast and be over ern KS. Cross-sections show a rather dry airmass over the area which would keep any tstm activity rather limited. Meanwhile will keep highs near seasonal normals. For Sat an upper level ridge will begin to build into the area from the swrn US. This would lead to warmer temps along with only a slight chc of tstms. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 732 PM MDT Sun Jul 26 2020 Weak upslope flow will probably generate areas of stratus and possibly fog around the Denver area and up the South Platte River valley after 4 am. IFR ceilings and visibilities may occur from about 4 AM through 8 or 9 AM Monday morning. Southerly winds developing after sunrise tomorrow should begin clearing out the stratus by late morning. VFR by midday with a chance of showers in the afternoon. Isolated thunderstorm at best so vcsh will suffice in the terminals for Monday afternoon. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Cooper SHORT TERM...Dankers LONG TERM...RPK AVIATION...Cooper
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
634 PM CDT Sun Jul 26 2020 .AVIATION... A few widely scattered showers this evening across the area as well as occasional thunder could potentially impact the San Antonio sites through about 02Z before the loss of daytime heating leads to these cells dying off. Expecting VFR conditions to deteriorate to MVFR at the I-35 sites late tonight with IFR cigs likely at AUS, and some light fog can`t be ruled out there either. For SAT/SSF, IFR cigs are possible but less certain, and at DRT VFR conditions are likely to prevail although cigs may come near thresholds late tonight into Monday morning so a brief period of MVFR cannot be completely ruled out. Should see the usual improvement by mid- morning (15-16Z). A few redeveloping showers will again be possible during the day Monday. && .PREV DISCUSSION... /ISSUED 219 PM CDT Sun Jul 26 2020/ SHORT TERM (Tonight through Monday Night)... Deep tropical moisture continues to stream over South Central Texas as Tropical Storm Hanna moves westward into northeastern Mexico. Pwat values of 2.0 to 2.4 inches have pooled over much of the region and daytime heating has reinvigorated the outer and far reaching rain bands of Hanna. Storms seem to be generating along the coast and over the Coastal Plains, likely from frictional convergence, and push further into the CWA as light to moderate rain showers. Bands of rain have been quick moving throughout the day. So even under the heaviest rain showers, certain isolated areas have only picked up about 2 inches of rain. High resolution guidance have some disagreement on handling convection later this afternoon with the NAM NEST showing a lull in activity till daytime heating gets going tomorrow but the latest 18Z HRRR and Texas Tech WRF show continued isolated activity through this evening. Keeping rain/storm chances in the forecast for much of the area given the sporadic nature of showers and storms the last 36 hours. Trimming back chances for rain overnight to areas along and south of I-10 and US 90. Moisture values remain elevated through the day on Monday but coverage of showers and storms should be less than what was seen today. Less cloud cover and less chances for rain will spell a bump back up in afternoon temps into the mid 90s, far southern zones may only make it to the upper 80s or low 90s with better chances for rain. Upper level pattern will remain slightly unstable with the subtropical ridge attempting to build in from the Desert Southwest but not close enough at the end of the long term to have any dominate features of the weather pattern. LONG TERM (Tuesday through Sunday)... Afternoon rain chances continue for Tuesday and Wednesday before the upper ridge gets hold of the area on Thursday. While under upper ridging, the forecast becomes dry and a warming trend ensues. The the end of the week and into the weekend, temperatures have crept back up to the triple digits for a good part of the area. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 74 95 75 93 76 / 20 30 - 20 - Austin Bergstrom Intl Airport 74 94 74 93 75 / 20 30 - 20 - New Braunfels Muni Airport 74 93 74 92 74 / 30 40 10 30 - Burnet Muni Airport 72 93 73 93 74 / 20 20 - 20 - Del Rio Intl Airport 74 95 76 96 76 / 30 30 20 20 10 Georgetown Muni Airport 74 94 75 94 76 / 20 20 - 20 - Hondo Muni Airport 73 94 74 95 75 / 30 30 10 30 10 San Marcos Muni Airport 74 93 74 93 74 / 20 30 10 30 - La Grange - Fayette Regional 75 94 76 94 76 / 20 40 20 30 - San Antonio Intl Airport 75 94 76 94 76 / 30 40 10 40 10 Stinson Muni Airport 74 93 75 93 76 / 30 40 10 30 10 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term/Aviation...KCW Long-Term...04
National Weather Service Sioux Falls SD
610 PM CDT Sun Jul 26 2020 .SHORT TERM...(This Evening through Monday) Issued at 239 PM CDT Sun Jul 26 2020 Mid afternoon surface observations show a weak cold front is situated roughly from Spencer to Sioux City Iowa and continues to progress southeast through the region. Radar and satellite imagery show an area of showers and storms developing with a weak shortwave disturbance across western NE, and some scattered showers and storms along and ahead of the front. Did keep slight chances of showers and storms across a portion of northwest IA to account for this and/or any additional isolated showers or storms developing before the front progresses southeast out of the forecast area. The latest few HRRR runs suggest activity across NE will progress eastward toward east central NE and west central IA this evening, remaining south of the forecast area. Suspect the majority of the region will remain dry through the rest of the afternoon and evening with decreasing clouds overnight. The axis of the upper trough tracking east through the Canadian prairie provinces will progress through the Northern Plains tonight, spreading notably drier air into the region for a pleasant Monday. The passage of the upper trough places the region in drier and milder northwest flow aloft. Dew points will fall to a more comfortable mid 50s to lower 60s by morning (vs 70s from the weekend). Surface high pressure will build through the forecast area overnight, resulting in lighter winds for at least early Monday. Expect a mild day with highs to reach the 80s for most locations under abundant sunshine. .LONG TERM...(Monday Night through Sunday) Issued at 239 PM CDT Sun Jul 26 2020 No impactful weather is expected until at least Wednesday as drier northwest flow aloft persists. For Tuesday and Wednesday, southerly flow and weak warm air advection develop, continuing high temperatures in the 80s to near 90 degrees. These days may gradually feel warmer as dew points creep back into the mid to upper 60s and perhaps lower 70s. For Wednesday night through Friday, there is good model agreement in a broad upper level trough digging into the central U.S. in northwest flow aloft. This system brings increased cloud cover and periodic chances for showers and storms, but there is significant uncertainty in the timing and general progression of the system. Ensemble guidance favors lower rainfall amounts for the late week period, less than a quarter inch on any given day for most locations. Some solutions have very little to no rain during this period. Thus late in the work week doesn`t look to be a total wash by any means, as the bulk of the precipitation is favored to track well south of the forecast area this point. Temperatures late week are expected to remain near normal values with highs in the 80s, but cloud cover and timing of the precipitation will bring some day to day subtle variations. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 610 PM CDT Sun Jul 26 2020 VFR conditions expected through the period. North-northwest winds will prevail at or below 10kt through mid-morning Monday, with occasional gusts nearing 20kt in southwest Minnesota at times Monday afternoon. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...BP LONG TERM...BP AVIATION...JH
Area Forecast Discussion
National Weather Service Goodland KS
538 PM MDT Sun Jul 26 2020 .SHORT TERM...(This evening through Monday) Issued at 1259 PM MDT Sun Jul 26 2020 18Z Surface observations and RAP analysis indicated pre frontal trough across the southeast corner of the forecast area. Observations as well as visible satellite indicate cold front steadily advancing south and was located between Wray and St Francis. Main concern will center around heavy rain through this evening and potential for localized flooding. Morning raobs continue to indicate near record values of precipitable water in place all around the area. The ample moisture combined with relatively deep warm layer and slow storm motions some what parallel to initial forcing provides a good set up for very efficient, heavy rain producing thunderstorms. Already have convective initation along trough and with continued forcing along front expect storms to steadily increase in coverage through the afternoon. While the initiation points are somewhat apparent, CAM`s suggest that once storms start, new development will be heavily driven by new outflows which will really lower the predictability with respect to location as storms evolve. Stayed closely to HREF mean representation of precipitation evolution but expect the details will remain somewhat murky. With very favorable environment and low FFG values, flash flood watch looks to be in good shape with the most likely area highlighted. Rest of the area should be on lookout for flash flooding as well as environment favorable over much of the area. As colder air works into area tonight, expect storms to gradually shift to the south through the overnight and morning hours. Atmosphere remains unstable to near sfc parcels through the night however, so storms may linger much longer than usual. Fog, low stratus and cooler temperatures will build into the area in the morning which will diminish precipitation threat. Atmosphere becomes capped through at least 22Z, so do not expect a lot of redevelopment, if any, until late afternoon. .LONG TERM...(Monday night through Sunday) Issued at 135 PM MDT Sun Jul 26 2020 Long range guidance suggests that WNW to NNW flow aloft will prevail over the Central/Northern Plains in this period -- on the N-NE periphery of an amplifying upper level ridge over the Desert Southwest/Intermountain West. A variety of small amplitude waves and/or convectively generated features may be present within WNW- NNW flow aloft over the Central/Northern Plains this week... none of which can confidently be anticipated at this range. With the above in mind, significant forecast uncertainty persists... particularly with regard to precipitation chances (i.e. location/ timing/coverage/evolution of convection). && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 508 PM MDT Sun Jul 26 2020 Expect TSRA at GLD through about 07Z with a transition from VFR to MVFR due to low ceilings and visibility by 07Z that may include intermittent LIFR due to lower ceilings between 11-13Z. MVFR conditions will improve to VFR again after 19Z Monday. MCK will see a few light showers and thunderstorms with VFR conditions through 09Z. Ceilings will lower to produce MVFR conditions after 09Z with intermittent IFR conditions between 11-14Z. Expect a return to VFR conditions after 18Z Monday. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...Flash Flood Watch through Monday morning for KSZ003-004-014>016- 028-029. CO...NONE. NE...NONE. && $$ SHORT TERM...JRM LONG TERM...VINCENT AVIATION...LOCKHART
Area Forecast Discussion
National Weather Service Indianapolis IN
1134 PM EDT Sun Jul 26 2020 .UPDATE... The AVIATION section has been updated below. && .SYNOPSIS... Issued at 400 PM EDT Sun Jul 26 2020 A cold front will move into the region Monday, bringing showers and thunderstorms to the area. This boundary will settle into the Ohio Valley and remain there for much of the week, producing chances for thunderstorms many days, with the highest chances in the south. The front will bring a welcome reprieve from the recent heat to the area. && .NEAR TERM /Tonight/... Issued at 400 PM EDT Sun Jul 26 2020 Most of the night should be quiet across central Indiana. There is some hint from the HRRR that weakening convective activity could sneak into northwestern portions of the area late tonight, and will carry some very low pops to account for this. Otherwise, expect mainly a gradual increase in mid and high cloud overnight. NBM temps appear reasonable and were generally accepted. Should see temps drop only into the low 70s overnight owing to increasing cloud cover and high dewpoints. && .SHORT TERM /Monday through Wednesday/... Issued at 400 PM EDT Sun Jul 26 2020 Main focus during the short term will be on Monday. Expect widespread convective activity along the front as it slowly moves through the area tomorrow. Instability should be plentiful, but shear will be quite modest at best. Primary convective mode should be disorganized multicell clusters...and the primary threat will be isolated downbursts/damaging wind gusts. Precipitation efficiency should be fairly high with a freezing level around 14kft and precipitable water values potentially in excess of 2 inches...or nearing plus 2 standard deviations for the time of year. Given the relatively weakly sheared environment, there will be a threat for flooding. Most thunderstorm activity will be south of the area by Tuesday morning. Will have to maintain low pops Tuesday but this is primarily on the chance that some activity near the boundary manages to sneak into our far south. Looks as though most of the area will be dry Tuesday into Wednesday. Temps look reasonable and required only minor adjustments through the period. && .LONG TERM /Wednesday Night Through Sunday/... Issued at 212 PM EDT Sun Jul 26 2020 The frontal system that is expected to move through the area tomorrow and stall Tuesday will slowly meander for much of the week. This front will interact with several weak upper level waves to bring isolated to scattered showers and thunderstorms. Confidence is fairly low in precipitation at any time, but is highest in the southern counties where the frontal system is more likely to be based on latest model guidance. A more substantial upper level wave is possible this weekend which could bring more widespread rain to the area. With northwesterly flow through the week, temperatures will be below average. && .AVIATION /Discussion for 27/06Z TAF Issuance/... Issued at 1134 PM EDT Sun Jul 26 2020 A cold front is expected to approach KLAF from the northwest after 21z. The front will interact with a hot and humid air mass and result in numerous MVFR or worse thunderstorms after 14z. Otherwise, good confidence in dominated VFR conditions tonight. Winds will start off southwest tonight and shift to the west after 21z. Wind speed with be around 10 knots much of the time with higher gusts in thunderstorms. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Nield NEAR TERM...Nield SHORT TERM...Nield LONG TERM....White AVIATION...MK
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
958 PM CDT Sun Jul 26 2020 .UPDATE... 955 PM CDT The loosely-defined, more outflow-driven MCS has gradually weakened as it has progressed southeast in our area. Some gusts with the outflow moving over far northwest Indiana and the southern Chicago suburbs are still 30+ mph, but these will continue to ease as they approach the Kankakee River Valley. On the southwestern periphery of this once MCS, there has been re- developing convection where 25-30 kt of 850-925mb flow (as sampled on the 00Z DVN sounding) is offsetting the weakening cold pool push. This has resulted in training convection over southern Lee and northern LaSalle Counties. Radar estimates of over 2 inches of rain, and at least one private gauge, has indicated this since 830 pm. Some flash flood guidance values are over 100 percent for parts of that area, but considering the more rural area and not extremely wet recently, have issued a Flood Advisory for now for mainly expected localized/minor flooding impacts. This should gradually sag east-southeastward after 11 PM. Otherwise going into the overnight, some warm advection aloft above 850 mb will continue impinging on and above the outflow boundary. The air mass will remain moist as the cold front is still well upstream (not passing until late morning/early afternoon), and there will be ample MUCAPE (>1500 J/kg). In addition there will be general lift from the right entrance region of a 100+ kt upper jet over the northern Great Lakes. However, there is not a well defined short wave, and the true low-level jet looks to be largely cut off by the broad swath of convection over Kansas into southern Nebraska and southwest Iowa. MTF && .SHORT TERM... 208 PM CDT Through Monday night... It`s definitely a hot and humid one out there this afternoon with dewpoints pretty homogeneously in the 74-77 degree range, although quite a bit lower across the more urbanized Chicago corridor owing to the increased/deeper mixing there. With the injection of this additional moisture (and through a not unsubstantial depth), cumulus has been percolating over the last hour or two. Noting a few areas of somewhat more agitated development where near-surface convergence is maximized, as well as an area from near Lincoln to Fowler where moisture is even a bit higher (dewpoints in the upper 70s to near 80 degrees). We`ll get some area-wide 20% PoPs going here by 3-4 PM, although coverage at least through 5 PM or so across most of the area may remain more of the 10-20% variety when taken as a whole. An outflow boundary exhausted from overnight/early-morning convection to our north has washed out quite a bit with the strong mixing chewing away at the shallow cold pool. Still, this feature appears to be evident in visible satellite imagery approaching a Cedar Rapids-Madison line with another more defined convergence axis about 30 miles farther northwest from there. We are effectively uncapped area-wide now, so any subtly enhanced convergence near these approaching boundaries or more developed Horizontal Convective Rolls could serve as a focus of initial isolated-scattered thunderstorm development through the rest of the afternoon. Latest thinking here is that we like the look of the 12z 3 km NAM, but just sped up by an hour or two based on the location of the upstream convergence axes with the other hires members trending more towards a solution we`d expect given the amount of instability present--even though we`re somewhat lacking in the large scale forcing for ascent department. 18z SPC Mesoanalysis plots depict DCAPE values have diurnally-built north of 1000 to almost 1500 J/kg in spots. This, combined with 0-3 km theta-e deficits approaching 35 K will support at least an isolated gusty/damaging wind threat into this evening. Should convection amass into a sufficiently robust complex to our north (and latest indications do point to that being a distinct possibility), this could locally enhance the gusty wind potential for our northwestern locales northwest of a La Salle to Evanston line and this is nicely demarcated by the most recent SPC Day 1 outlook. Given the dearth of faster mid-level flow (and any deep layer shear really oriented boundary-parallel), any hint at cold pool development would allow an outflow boundary to relatively quickly surge south and eastward this evening with limited potential for additional storm organization. As such, any localized severe threat should wane with time towards the midnight hour, and thunderstorm chances will commensurately follow on a downward trend. What happens very late tonight and into Monday morning remains a little unclear given the most recent CAM guidance. Coarse- resolution guidance is in good agreement that upper jet divergence will actually start to increase towards 5-7 AM on Monday within a still richly-moist airmass with the cold front probably just entering northwest Illinois. RAP guidance develops quite a bit of dry air in the 850-700 mb layer, while the ECMWF and others remain more saturated during this period. As such, suspect we may see some renewed development or at least some "festering" of lingering showers/storms. Don`t necessarily like the look of the NAM trying to lay out convection west-to-east during this period but, unlike the situation south of Minneapolis last night where training convection produced upwards of 6-8" of rain, we really don`t see indications of the 925-850 mb flow strengthening or backing sufficiently to support a big blob of low-level warm advection atop whatever composite outflow/frontal boundary may be nearby. With this in mind, have attempted to inflate PoPs a bit very late tonight and into Monday morning with a continued message of a threat for locally heavier rainfall corridors. Drier air will finally invade through the afternoon hours, but we`ll likely continue with showers/storms at least south and east of I-55 into the mid-afternoon hours. Main instability axis looks to push just southeast of our area, likely limiting any severe threat but sporadic gusty winds will certainly be possible within any more precip-loaded downdrafts. Clearing and more quiescent conditions roll in for Monday night. A lingering slight breeze through the night may ultimately help hold temperatures up a bit, but wouldn`t be surprised to see some mid- upper 50 degree readings near out outlying/typical cool spots. Carlaw && .LONG TERM... 229 PM CDT Tuesday through Sunday... Generally dry conditions with more seasonable temperatures are expected through much of this period as broad troughing drifts east across Ontario and Quebec this week. Weak low-level WAA from northern Iowa into northern Ohio late Tuesday afternoon through Wednesday will act on a pocket of Pacific moisture with some enhancement from the Gulf of Mexico. Have opted to keep the forecast dry during this time with the expectation of very low coverage with enhanced cloudiness. A more pronounced trough axis rotating south around the eastern Canadian trough will interact with a group of troughs meandering across the Rockies and southern Great Plains, including some of the remnants of/moisture from Hurricane Hanna, will interact with the northern trough across the Ohio River Valley by Thursday. The northern fringes of the resultant system may affect southern portions of the CWA late Wednesday night into Thursday night. Meanwhile, stronger north to northeast winds in a weakly stable environment over Lake Michigan Thursday into Friday will promote increased wave action and potentially dangerous swim conditions for the IL/IN beaches. Troughing then builds back into the region for the weekend with the potential for a weak embedded shortwave bringing a focused period of precip chances, but given model differences and an increasingly complex pattern across the CONUS, targeting a specific period (if there is one) is not possible at this time. Kluber && .AVIATION... For the 00Z TAFs... The concerns for the Chicago area airports are: - Gusty storms for a 1-2 hour evening period, with the likelihood of gusty outflow reaching 30-60 minutes prior to the storms - Gusty southwest winds turning northwest with the storms, then becoming light west-southwest into overnight before turning northwest on Monday late morning - Chance for showers and MVFR ceilings Monday morning - Chance for a lake breeze at MDW later Monday afternoon An area of semi-organized storms in southern Wisconsin to northwest Illinois will move slowly southeast through the evening and is expected to have a gradual weakening trend. This is outflow-dominant, in that it is pushing rain-cooled air out ahead of it, with gusts to 25+ kt possible with just this outflow. Underneath the storms themselves some gusts to 35 kt are possible at ORD and MDW and likely at RFD. Also rainfall rates under any of these storms, despite weakening, should present some brief visibility into the IFR category. Confidence on storm trends and timing in the TAFs is medium-high. Behind the main area of storms, scattered showers are likely to linger. There are signs that showers may pick up some very late tonight into early-mid Monday morning. Confidence on that is low, but the signal for thunder during that time is also on the lower end. Patches of MVFR ceilings seem probable tonight into Monday morning, but the signal has diminished. After the wind effects of the evening storms, winds will turn west-southwest for a period overnight and mainly light. With a cold frontal passage Monday morning, the winds will then turn northwest with some sporadic gusting likely in the afternoon. A lake breeze will develop, mainly into northwest Indiana, but some of northeast Illinois within a few miles of the shore will see the wind shift and it may reach MDW later in the afternoon. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Paducah KY
522 PM CDT Sun Jul 26 2020 .UPDATE... Issued at 518 PM CDT Sun Jul 26 2020 Updated Aviation discussion for 00Z TAF Issuance. && .SHORT TERM...(Tonight through Tuesday night) Issued at 308 PM CDT Sun Jul 26 2020 Convection got off to an early start today, and as expected the thunder has been most prevalent over west Kentucky this afternoon. It should push east of our area by 21Z. A few light showers will remain across the region, and an isolated thunderstorm cannot be ruled out through sunset. We should be dry and mostly clear tonight, but HRRR runs have been consistently trying to bring some convection eastward along I-64 in southern Illinois toward sunrise. Confidence is not high enough to add it to the forecast right now. The cold front is still expected to reach the area generally after 21Z Monday. Not sure how much convection there will be ahead of it, but figure on widely scattered showers and storms possibly beginning before noon, especially across the north. The flow will be weak, so any storms will be of the pulse variety and should not lead to any damaging winds or significant flooding issues. The hi-res guidance has consistently shown a major downward trend in coverage and intensity as the frontal-related convection moves south through the northern half of our region in the 21Z-03Z time frame. The shear will remain weak and instability will not be much better than we have had recently, so severe storms would be quite the stretch, but a stray downburst cannot be ruled out, especially along I-64 in the late afternoon. Also should not see much of a heavy rainfall and flooding concern. Not sure how much, if any, convection will make it into southern portions of the area heading into the overnight hours, but PoPs will drop to chance levels by late evening and remain there overnight. Not sure where the actual synoptic boundary will be Tuesday morning, but it is not likely to clear west Kentucky. Given the uncertain convective coverage overnight, the outflow may not even clear the area. Regardless, convection is likely to develop in the vicinity of the cold front and any outflow boundaries by late Tuesday morning. This will be the best chance for convection over the southeast half of the area. Once again, there will not be enough shear to organize it, so more non-severe, pulsy storms are expected. Given a nearly stationary boundary, the heavy rainfall threat will be a bit higher Tuesday. Far northern portions of the region should be dry Tuesday afternoon, but will leave a small chance just in case the cold front holds up a bit farther north than expected. The convection Tuesday should be widespread enough to push the effective surface boundary south of the area by Tuesday night, so most if not all of the region will be dry Tuesday night. Temperatures Monday will feel similar to the last few days, with high temperatures around 90 and heat indices topping out near 100. With the front and associated convection and cloud cover, Tuesday will be noticeably less hot, especially across the north. .LONG TERM...(Wednesday through Sunday) Issued at 308 PM CDT Sun Jul 26 2020 The extended forecast period looks rather unsettled. However, the details regarding the timing and duration of significant POPs remain murky at this time. Forecast confidence is high to start the period, but declines for next weekend. From Wednesday through at least Friday, a stalled surface boundary will be positioned along the southern border of the CWA. Aloft, the region will be under the influence of northwest flow, with pieces of energy disseminating from a trough digging into the Northern Rockies bringing chances of scattered thunderstorms. By Thursday and Friday, a surface inflection will organize over the Southern Plains and traverse along the stationary boundary. This system could bring multiple rounds of locally heavy rain to the CWA. Ensemble guidance shows PWATs above the 90th percentile during much of this period, so efficient rainfall processes are possible. Latest QPF shows widespread 2-3+" totals by Saturday evening. This is still subject to change at this range, however. Deterministic model guidance has trended wetter for Saturday (possibly into Sunday as well). This is due to the progged development of a secondary area of low pressure along the stationary boundary. We thought the NBM solution of chance POPs for Saturday was an acceptable solution for now. Temperatures will trend cooler through the forecast period, owing to the ample cloud coverage and precipitation chances. High temperatures will generally be in the lower to middle 80s, with overnight lows in the upper 60s. Dew point temperatures will not come down much, so it will still feel quite humid outdoors. && .AVIATION... Issued at 518 PM CDT Sun Jul 26 2020 Widely scattered convection continues in the late day heat, and will remain a vicinity possibility until sunset or shortly thereafter. Will let latest radar trends dictate its inclusion. Otherwise, another scattering of VFR skies tonight is expected, with a repeat (diurnal) scenario tmrw as cu field develops by mid-late morning. Short res models suggest we might see early convection coming in from the northwest, so included vicinity mention with VFR cigs/bases at KMVN for this writing. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$
Area Forecast Discussion
National Weather Service Pueblo CO
1002 PM MDT Sun Jul 26 2020 .UPDATE... Issued at 1002 PM MDT Sun Jul 26 2020 Updated the forecast to add another flash flood watch for tomorrow afternoon and evening for the area burn scars. With the monsoonal moisture in place, we are expecting for another round of slow moving thunderstorms tomorrow afternoon. This will combine with areas of saturated soils from previous days precipitation for the potential of flash flooding once again, especially for the burn scars. && .SHORT TERM...(This evening through Monday) Issued at 237 PM MDT Sun Jul 26 2020 Currently Scattered thunderstorms and numerous showers were noted over the forecast area at 2 pm. The strongest storms were noted in the KTAD area and across eastern Baca County. Other showers and storms were noted over the mtns/plains interface. A cool front was on the Palmer Divide and was about to move into El Paso county. Rest of Today and into Tonight... Main concern is what is going to happen in the next several hours. Cool front will continue to push south in the unstable airmass over southeast CO. Between 500 and 2000 J/kg of mixed CAPE were noted over the region with the most unstable air over the far SE Plains. HRRR continues to indicate (as it has been doing since I got into the WFO at 8 AM) to show the strongest activity in the mtns is going to occur over the mtns/plains interface. In addition, storms over S Lincoln County have put out a boundary and it was pushing west and south, and storms in the KTAD area are likely going to push a boundary northward. Likewise, I would not be too surprised to see some strong storms fire in the Pueblo County area and eventually push east later this afternoon. Based on the HRRR guidance, a significant flash flood threat is still possible for all of the burn scars along the Wets and Sangre mtns, especially once the main front moves down into that region. For the rest of the period, storms will slowly subside over the higher terrain this evening while a cluster of storms slowly pushes east across the plains. These storms may linger well into the evening and early morning hours. We will likely see quite a bit of clouds with areas of low cigs over the plains tonight. Tomorrow... Main change to the fcst is the potential for less precip over most of the region tomorrow. Temps are going to be rather cool tomorrow 70s and 80s plains) and this is likely going to stabilize the atmosphere. I have cut back pops quite a bit on the plains, but later shifts may need to cut them back even more. In the mtns, especially along the contdvd, the threat of locally heavy rain will still be with us and kept high pops over this region. /Hodanish .LONG TERM...(Monday night through Sunday) Issued at 237 PM MDT Sun Jul 26 2020 On Tue the upper level ridge is expected to be centered near the southern CA coast, while an upper disturbance moves thru WY and northern CO. There will be a little less moisture over the area Tue, but still plenty around for scattered showers/storms over and near the mtns, then spreading over the plains in the evening hours. Wed the upper ridge becomes centered over AZ, with northwest flow aloft over the forecast area. Moisture is expected to be lacking on Wed, but the far eastern plains may have the best moisture and some isolated storms may be possible. There could also be some isolated showers/storms over some of the mtns as well. A disturbance moves into KS on Thu, while the upper ridge becomes centered near the Four Corners. Little moisture is expected over the area on Thu but there could again be some isolated showers/storms, especially near the eastern border. Fri and Sa the upper ridge center is expected to be over northeast AZ and a little more moisture is expected over the mtns, especially the eastern mtns, so maybe scattered showers/storms may form over the mtns and portions of the I-25 corridor in the afternoon and possible over the southern plains in the evening. Sun the upper ridge may shift westward and the models show a disturbance affecting the area and potentially bringing better chances for precip. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 237 PM MDT Sun Jul 26 2020 Thunderstorms, some with very heavy rain, are still a threat for later this afternoon and evening at all 3 taf sites, KPUB, KALS and KCOS. The heaviest rain threat will be at KCOS and KPUB. Another concern will be low cigs tonight given the abundant low level moisture over the plains. Storm threat for tomorrow afternoon is decreasing at all 3 taf sites as more stable air is fcst to move into the region. && .PUB WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch until midnight MDT tonight for COZ061-062- 072>075-077-079-080-087. Flash Flood Watch from Monday afternoon through Monday evening for COZ061-062-072>075-077-079-080-087. && $$ UPDATE...MW SHORT TERM...HODANISH LONG TERM...28 AVIATION...HODANISH