Area Forecast Discussion
Issued by NWS Oklahoma City, OK
Issued by NWS Oklahoma City, OK
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191 FXUS64 KOUN 162346 AFDOUN Area Forecast Discussion National Weather Service Norman OK 646 PM CDT Tue Jul 16 2024 ...New AVIATION... .SHORT TERM... (This evening through Wednesday) Issued at 343 PM CDT Tue Jul 16 2024 Current Heat Advisory remains in effect through 8 PM with heat indices currently 105-108 degrees across much of our area. Storm chances return late this afternoon through tonight across parts of northern, central, and western Oklahoma with severe storms possible. A mid-level shortwave rotating through a synoptic ridge over much of the Western U.S. will be moving across the Central through Southern High Plains this evening and across northern OKlahoma late tonight. Meanwhile further north, a fairly large amplitude trough in the main jet flow across the U.S. Northern and Central Plains to the Upper Midwest Regions will be pushing a summertime cold front/surface boundary across our area. The surface boundary had been stalled out across southeast Kansas to the Oklahoma Panhandle but is now starting to push into far northwest Oklahoma. Surface & elevated instability is strong up to 3000-3500 J/kg within the trough where lapse rates are steeper while slightly weaker to more moderate values south of the surface boundary in the warm sector. Deep-layer shear is marginal across the Central Plains although weakens into northern Oklahoma so overall our area is in a high CAPE/weak sheared environment with tonight`s system as far as severity. We`ll likely see two periods/mechanisms of convection developing, the first could be triggered by diurnal heating late this afternoon till sundown in the warm sector extending from I-40 up to the Kansas state line. These first round of storms could be more isolated and short-lived although the environment could produce strong to severe downburst wind gusts. The stronger nighttime convection will be the second round as an MCS associated with the mid-level shortwave rotating through, with additional surface-based storms along the cold front when it starts pushing through. Although models have the MCS activity ramping up after midnight, there could be a brief lull in the activity after sundown unless the surface boundary starts pushing through. This MCS will mainly impact northern Oklahoma with heavier rainfall and a potential of severe storms. The weak shear environment should inhibit any organized severe weather but could still see severe damaging wind gusts as DCAPE values will be sufficient and can`t rule out some low-end severe hail (quarters) across far northwest Oklahoma. Overall, a Marginal risk for severe storms late this afternoon until after sundown across the northern two-thirds of our CWA with a 20-30% probability of storm development. A Marginal to Slight risk across the northern one-third of our CWA late tonight with a 40-60% probability of storms developing. Our CWA should be post-frontal by Wednesday afternoon with the exiting MCS keeping storm POPs generally along and east of I-35. Although slightly cooler on Wednesday with temperatures becoming more seasonable average (90s), not seeing any dry air behind the front so will still be quite muggy with near 70 degree dewpoints. Although a stronger cap south of the Red River, diurnal heating under a weak cap to the north could fire some late afternoon convection across much of our Oklahoma CWA so will keep low storms POPs into the evening, although weak surface-based instability should keep any isolated storms weak should any pulse up. && .LONG TERM... (Wednesday night through next Monday) Issued at 343 PM CDT Tue Jul 16 2024 The upper ridge will persist over the Western U.S. through the Southern Plains at least through Friday as temperatures should remain near seasonably average although still humid. This should keep our heat indices below triple digits. As far as rain/storms, could see another MCS Wednesday night with another shortwave rotating through the closed ridge although models project that wave over eastern New Mexico and less impactful in our area. However, a weak trough digging into our area could result in some non-severe elevated storms on Wednesday afternoon and overnight mainly south of I-40. South winds return on Saturday with another trough digging through from the north which could be pushing our next summertime cold front through on Sunday. Rain/storm POPs will return Saturday into Sunday and fairly widespread across our area with this weekend system coming through. We could see cooler than average temperatures by Sunday into early next week with highs in the 80s with less humid air filtering in behind it at least affecting the western half of our CWA. && .AVIATION... (00Z TAFS) Issued at 646 PM CDT Tue Jul 16 2024 There are some scattered thunderstorms this evening across western Oklahoma, generally south of KWWR and at least right now mostly north of KCSM, but may affect the KCSM vicinity as they drift slowly southeast. These initial storms may decrease in coverage early this evening after sunset, but a thunderstorm complex developing in southeast Colorado and the western Oklahoma panhandle is expected to move east and affect the northern Oklahoma TAF sites. There could be severe weather with these storms this evening, primarily strong winds. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 74 89 68 88 / 30 30 20 10 Hobart OK 74 92 68 91 / 20 30 20 20 Wichita Falls TX 79 96 71 92 / 0 20 30 20 Gage OK 69 89 64 88 / 60 30 10 10 Ponca City OK 72 88 66 87 / 60 40 10 0 Durant OK 79 97 71 92 / 10 30 40 30 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...Heat Advisory until 8 PM CDT this evening for OKZ007-008-012-013- 016>048-050>052. TX...Heat Advisory until 8 PM CDT this evening for TXZ083>090. && $$ SHORT TERM...68 LONG TERM....68 AVIATION...26