Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/12/24


Area Forecast Discussion
National Weather Service La Crosse WI
1041 PM CDT Thu Jul 11 2024 .KEY MESSAGES... - Some fog potential overnight, otherwise a quieter day expected for Friday. - Temperatures increasing into the weekend with highs in the upper 80s to low 90s and heat indices nearing 100 by Sunday. - Monitoring how the risk for severe weather unfolds for Saturday evening through Tuesday. The forecast remains complex and of lower confidence. && .DISCUSSION... Issued at 318 PM CDT Thu Jul 11 2024 Rest of Today - Tomorrow: Currently, GOES-16 water vapor imagery and 11.14z RAP 500mb heights shows a synoptic trough slowly pushing eastbound with a shortwave ridge positioned to our northwest. As we head through the afternoon, increasing instability (1000-1500 J/kg of MLCAPE) and some weak cyclonic flow may help develop showers, maybe an isolated storm. However with very weak shear profiles in the 11.14z RAP, would not expect any convective development to maintain in any organized fashion. However, with the 11.12z HREF showing ensemble max values for 3-hr QPF of up to around 1", could not completely rule out extremely localized areas receiving some higher totals. As we head into tonight, subsidence builds in with the aforementioned ridge allowing for more clearing in sky cover and calming winds. As a result, expecting some fog formation overnight, primarily in river valley locations and in central Wisconsin. Still some questions for coverage and density for fog with the 11.12z NAM trying to hold onto some saturation at 850mb in addition to some increased low-level winds at 925mb to around 10 kts. Regardless, with the aforementioned subsidence in place, should be a drier forecast for Friday outside of a few possible sprinkles across north- central WI with temperatures reaching into the middle 80s for most. Saturday - Sunday: A challenging forecast remains for the weekend as we monitor the potential for storms. The ridge that has persisted over the West is forecast to build towards the region on Saturday with a series of upper level shortwaves riding around it. With increasing moisture and warm air advection beneath an EML, strong instability looks to build across the region. Some indication in model guidance for elevated convection to develop early as one of the aforementioned waves moves through. However, as we continue to move into the day there remains some concern revolving around capping. Latest ensemble guidance, as an example/proxy, keeps us right on the eastern edge of the 700 mb temperature probabilities for 12C+ with model forecast soundings showing a bit less of a capped environment in the east. With a weak moisture transport convergence signal into southern Wisconsin along with the warm front, guidance suggests this could be enough to get showers and thunderstorms to develop. However, there seems to still be plenty of variability on how that evolves. Will need to continue to monitor trends over the next day or so, especially as we remain in a slight risk for severe weather from SPC. The story remains the same as with previous forecasts for Sunday, which will be dependent on Saturday`s convection as well as the strength of the cap building across the area. Model guidance again diverges quite a bit on how exactly this unfolds and where storms track. Overall though, current thinking would be that storms will track along the gradient of the instability pool and weaker capping (potentially favoring more north/northeast). With the strong instability and better shear to work with will be closely monitoring over the next couple days for the potential for severe weather. Of higher confidence is for increasing temperatures into the weekend. Sunday still looks to be the warmest day coming up, with current forecast high temperatures in the upper 80s to low 90s. This is supported by quite low spread (~2-3 degrees) between the 25th and 75th percentiles of the blended model guidance. There does not look to be much relief for the overnight as temperatures only drop into the 60s to low 70s. With the addition of increased dewpoint temperatures, heat indices may rise into the 90s to near 100 for some especially Sunday. Now, will note that one wrench in this would be any impacts from potential convective systems Saturday night into Sunday morning. Something to monitor as these details become more clear, but for now will continue to message the heat. Into Early Next Week: Some signal for an upper level trough to move across the region with additional showers and storms possible. However, it is uncertain how any convection on Sunday will impact storms on Monday. Otherwise, the heat does not look to last long as temperatures drop back to the 70s by mid-week. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1028 PM CDT Thu Jul 11 2024 Primary concern remains to be valley fog along the Mississippi and Wisconsin rivers and their tributaries. Light wind layer and clear skies at 12.06Z TAF issuance increases confidence for dropping into LIFR visibilities and ceilings. Therefore, have introduced BR and 003 ft ceilings. Otherwise, VFR with light winds through Friday. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...EMS AVIATION...JAR
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1140 PM EDT Thu Jul 11 2024 .KEY MESSAGES... - Hotter conditions make a comeback as we move into the weekend and for next week. - The next significant chance of rain will hold off until the middle of next week. && .UPDATE... Issued at 1140 PM EDT THU JUL 11 2024 A weak mid-level wave is pushing across the Ohio Valley. This continues to lead to a few showers right along our CWA border mainly in Rockcastle and Pulaski counties. Did keep this for a few more hours in these areas, but these are expected to dissipate later this evening into the overnight. The NBM PPI continues to be of little help in the situation and favored some of the other short term models and blends for adding these PoPs in longer. Outside this very minor updates needed for the latest obs and trends. UPDATE Issued at 819 PM EDT THU JUL 11 2024 A few rain showers have developed right along our CWA border near Pulaski and Rockcastle counties. Given this opted to add in around 15 to 20 percent chance of rain in these locations. Outside of that no big changes needed. UPDATE Issued at 558 PM EDT THU JUL 11 2024 The surface analysis shows high pressure continues to work into the Great Lakes this afternoon. In the mid-levels, a shortwave trough is pushing across portions of the Ohio Valley. This is aiding in sparking off a few showers and thunderstorms to the northwest of eastern Kentucky. Most of the CAMs have this activity decreasing through the evening, but the HRRR has shown some signs this could maintain and get closer to the area late this evening. Right now leaning toward dry weather through the evening, but did opt to increase cloud cover given the latest trends on Satellite. Outside this overall minor updates were made to the forecast. && .SHORT TERM...(This evening through Friday night) Issued at 320 PM EDT THU JUL 11 2024 Current surface analysis has surface high pressure situated over the much of the eastern CONUS. The remnants of Beryl is exiting off the northeastern coast and a weak surface low is tracking across the Central Plains with a wavering frontal boundary extending into the Ohio Valley. Locally, high pressure is keeping the CWA warm and dry with a widespread field of fair weather cumulus clouds. Aloft, troughing is situated over the Great Lakes with the CWA under the regime of the upslope side of the trough. Through the afternoon into Friday, the trough will pivot through the area. At the surface, high pressure will remain in place but a few showers and storms may try to develop this afternoon along the aforementioned frontal boundary but those PoP chances will largely remain confined to areas west of the CWA. Clouds will decrease overnight and a decent ridge- valley split will set up tonight; as well as, areas of patchy dense valley fog. Friday brings much of the same weather as surface high pressure remains in place. The upper-level trough will pivot through the area but once again, not expecting much in the way of PoPs. CAMs try to bring a few isolated showers or storms to the I-75 corridor but chances are less than 15% in those areas. Similar to Thursday night, a mostly clear night is expected again Friday into Saturday where a ridge-valley split sets up and valley fog will develop and persist through early Saturday morning. Overall, the period will be dry with passing clouds. Highs are forecast to be in the mid to upper-80s today before climbing into low 90s for Friday. Overnight lows will remain mild across the area too, as lows tonight will drop into the low to mid-60s and mid to upper-60s for Friday night. .LONG TERM...(Saturday through Thursday) Issued at 320 PM EDT THU JUL 11 2024 The first several days in the extended should be hot and mostly dry, as high pressure settles over portions of the southeastern and southern CONUS. We might see a few showers and storms Sunday afternoon north of Highway 80, and again Monday evening, as a couple of weak disturbances pass by to our north. Our next good chance will likely not arrive until late Tuesday, as a more substantial system moves across southern Canada, and drags a cold front through the Great Lakes and Ohio and Tennessee Valleys. It appears that the front will get hung near or over our area by Wednesday, keeping rain chances in the forecast through near the end of the week. Weak impulses moving along the sluggish boundary will be triggers for showers and storms as well. As for temperatures, it looks like we will see a return to hot and muggy conditions in the extended. The latest run of the NBM was way too hot for Monday and Tuesday, and initially had highs on those two days maxing out in the mid to upper 90s, which would be incredibly difficult to achieve in our area. Even with dewpoints expected to rise into the upper and lower 70s, we should still see daily highs mainly in the lower 90s, with a few locations perhaps reaching the mid 90s. We should see a nice cool down at the end of the period, as the cold front drifts to our south and persistent rain and clouds are in place. Highs next Thursday should only be in the low to mid 80s. As far as weather concerns go, we will keep an eye on just hot and humid conditions become the first few days next week. If any concerns arise with regards to the heat, we will keep everyone informed. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) ISSUED AT 731 PM EDT THU JUL 11 2024 The period will remain mostly VFR across eastern Kentucky. We have seen cumulus develop this afternoon at around 5 to 6 kft. These have been producing some showers just to the west of eastern Kentucky, but not expecting any showers to affect TAF sites at this point. We could see these clouds stick around through the evening before dissipating later tonight. Once clouds dissipate we will see the potential for valley fog developing under clear and calm conditions. Given this added in fog at SME, but otherwise kept other sites VFR for now. This fog is expected to dissipate around 12Z and VFR will return area wide for the remainder of the period. The winds will remain light and variable for the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DJ SHORT TERM...VORST LONG TERM...AR AVIATION...DJ
Area Forecast Discussion
National Weather Service Springfield MO
654 PM CDT Thu Jul 11 2024 .KEY MESSAGES... - Scattered showers and thunderstorms into Friday. A few storms may produce wind gusts up to 60 mph and hail to the size of quarters into this evening. - Heat indices climb into the 100-107 degree range from Sunday through Wednesday. - A cold front will bring the potential for more thunderstorms to the region next Wednesday or Thursday along with cooler temperatures. && .SHORT TERM /THROUGH FRIDAY/... Issued at 154 PM CDT Thu Jul 11 2024 Synoptic Scale Pattern and Current Conditions: Water vapor imagery depicts a short wave trough diving southeast across the Great Lakes with a secondary lobe of vorticity dropping south across the Corn Belt. At the surface, a front has stalled out in the vicinity of the I-70 corridor from northeast Kansas into Missouri. An outflow boundary from morning storms is dropping south through central Missouri and is becoming more diffuse with time. A loose cluster of showers and thunderstorms that persisted for much of the morning, has now almost vanished in the vicinity of Rolla and Dixon. Sky conditions as of 2 PM range from mostly sunny to partly cloudy. Temperatures over most areas have warmed into the middle 80s to lower 90s. A few locations across central Missouri remain in the lower 80s due to slightly greater cloud coverage. Thunderstorm Potential through Mid-Evening: Upper level ascent will increase as that short wave trough in the Corn Belt moves into northern Missouri. In addition to the upper level ascent, surface temperatures will near convective temperatures which are in the upper 80s to lower 90s per the 12Z KSGF RAOB as well as short term RAP initializations. These factors along with weak convergence along that outflow boundary will result in widely scattered thunderstorm development into early this evening. MLCAPE values ahead of the outflow boundary will be in the 1500-2500 J/kg range with deep layer shear of 25-30 knots. This will be supportive of a few storms potentially reaching marginally severe levels. Hail to the size of quarters and damaging wind gusts to 60 mph will be the primary potential severe weather hazards. Low temperatures tonight will range from the middle 60s across the eastern Ozarks to the lower 70s around Joplin and Neosho. Thunderstorm Potential from Late Tonight into Friday Morning: That surface front will remain stalled somewhere near or just south of I-70. Meanwhile, short term models are in good agreement that a low-level jet will develop and strengthen across Oklahoma and eastern Kansas starting late this evening. This feature will then veer into far western Missouri starting late tonight. Lifting parcels from planes in the 850-750 mb layer yields 800-1600 J/kg of CAPE with little in the way of inhibition. We therefore think that isentropic upglide will initiate widely scattered elevated thunderstorms across western and central Missouri after midnight. This activity will then slowly work east across the Missouri Ozarks through Friday morning. The main potential hazards with overnight and Friday morning activity will be hail to the size of pennies and perhaps wind gusts to 50 mph if wind can penetrate the nocturnal inversion. Friday Afternoon and Friday Night: Morning activity may very well survive into the afternoon as it pushes into the eastern Ozarks. Otherwise, a few pop-up storms will be possible (20- 30% chances) primarily across the eastern Ozarks during peak heating. A capping inversion may limit, or completely eliminate any potential for convective development in the afternoon along and west of the Highway 65 corridor. The experimental Ozarks Pulse Severe Thunderstorm Index indicates that any storms that form across the eastern Ozarks Friday afternoon will have the potential to produce damaging downbursts and perhaps hail to the size of quarters. Until we can get a better feel for thunderstorm potential Friday afternoon, we are going to continue adverting wind gusts to 50 mph and hail to the size of pennies as the primary convective hazards across the eastern Ozarks. Wind gust and hail size values may need to be nudged upward in future forecasts. A slow warming trend will continue into Friday as a ridge over the western U.S. slowly continues to build east. The NBM shows tight clustering with high temperatures on Friday. Thus, confidence is high that temperatures will range from the middle and upper 80s across the eastern Ozarks to the lower and middle 90s along the I-49 corridor. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... Issued at 154 PM CDT Thu Jul 11 2024 Friday Night into Saturday: That warm front will lift north as the upper level ridge continues to build east. Most ensemble members keep the Ozarks dry for this period with thunderstorm activity well north and east of the area closer to that lifting warm front. One alternative scenario depicted by some short term ensembles is the development of elevated convection and potentially even an MCS across northern Missouri from late Friday night into Saturday morning. If the MCS scenario were to materialize, wind fields would support the MCS dropping south into central Missouri and the eastern Ozarks. If we remain dry with little in the way of cloud cover (the most likely scenario) on Saturday, we will have no problem continuing our warming trend with most areas warming into the lower and middle 90s. If the MCS scenario does indeed come to fruition, we would see slightly cooler temperatures due to the precipitation and cloud cover. Sunday into Tuesday: Global ensembles show strong agreement that the upper level ridge will continue to build east into the area. Dry weather and hot conditions will be the result. Highs by Monday and Tuesday will be in the middle 90s to around 100 degrees with the warmest readings along the I-49 corridor. Confidence is high in these temperatures given that the NBM statistical data only has 2-4 degree spreads between its 25th and 75th percentiles. We are still expecting afternoon heat indices of 100-107 degrees early next week as dew points remain in the middle 60s to lower 70s. Heat headlines will correspondingly be in play. Wednesday and Thursday: Global ensembles continue to depict a large amplitude upper level trough diving southeast through Hudson Bay and the Great Lakes. We are becoming increasingly confident that this trough will drive a cold front south either into or through the Missouri Ozarks. This is supported by the vast majority of global ensemble members. The passing front will bring us our next shot at showers and thunderstorms along with a return to near or slightly below normal temperatures. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 654 PM CDT Thu Jul 11 2024 Isolated showers and storms will continue to develop across portions of west central and central Missouri this evening. The better potential for this activity will remain north of the TAF sites this evening so have not included any mention for convection in the TAFs for this evening. Even with the storms remaining north of the area it is possible that outflow from the storms could move south into the TAF sites this evening and result in a brief wind shift. Other wise south to southeasterly winds will occur through the TAF period. Additional scattered storms will be possible across the area late tonight into Friday morning as lift moves into western Missouri. Have PROB30 group for this thunderstorm potential in both the Joplin and Springfield TAFS. Brief MVFR to IFR conditions and erratic winds will be possible with any storms. && .CLIMATE... Issued at 154 PM CDT Thu Jul 11 2024 Record High Minimum Temperatures: July 15: KSGF: 79/1954 July 16: KSGF: 81/1914 July 17: KSGF: 79/1934 && .SGF WATCHES/WARNINGS/ADVISORIES... KS...None. MO...None. && $$ SHORT TERM...Schaumann LONG TERM...Schaumann AVIATION...Wise CLIMATE...Schaumann