Area Forecast Discussion
Issued by NWS Springfield, MO
Issued by NWS Springfield, MO
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237 FXUS63 KSGF 201946 AFDSGF Area Forecast Discussion National Weather Service Springfield MO 246 PM CDT Mon May 20 2024 .KEY MESSAGES... - Another warm day is in store for the region Tuesday ahead of a cold front then a return to more seasonably mild temperatures. - Chance for a storm or two across central MO into this evening otherwise dry overnight into Tuesday morning. - Severe storms possible late Tuesday afternoon into the evening...with an Enhanced (3 of 5 level) risk over west central and central MO and a Slight Risk for much of the region southward to the Arkansas border. Damaging wind gusts are the primary concern followed by large hail. The tornadop threat is limited. - Potential for another round of severe weather Wednesday toward south-central Missouri (15% risk/confidence). - Unsettled weather may persist through the end of this week and into Memorial Day weekend (daily 30-50% chances for showers and thunderstorms). && .SHORT TERM /THROUGH TONIGHT/... Issued at 215 PM CDT Mon May 20 2024 OVERVIEW... Little change in the overall weather pattern featured by shortwaves rotating through the western trough through the Plains with related surface fronts/outflow boundaries being slow to clear the region. Challenges in this regime exist in timing and intensity of associated convection and culmulative impact of rainfall leading to a flood threat. An early-morning MCS left behind a wake low in eastern Kansas, and pulse-like storms were forming along a boundary of favorable convergence caused by interactions with a mesohigh near Kansas City. These storms have pretty much petered out due to a lack of favorable environment, with a cap developing and limiting convection in west- central Missouri. This cap will likely erode going into the late afternoon hours, but forcing for storms remains questionable, making the thunderstorm potential very conditional for the northern extent of our Missouri counties. Remnant boundaries seen on satellite from morning convection seem both unlikely and unsupported by models to persist into the evening hours, but if any of those are able to withstand synoptic-scale sinking motion, those will be the areas to watch as the primary source of lift for any storms. A low-level jet will advect moisture and potentially provide an additional source of lift for thunderstorms towards the middle of the night, but whether it gets far enough east to become impactful to central Missouri remains to be seen. An additional confounding factor to this conditional setup is moisture- boundaries are set up along mesoanalysis-indicated deep moisture convergence, while mid- and low-level water vapor satellite imagery, in addition to NUCAPS soundings, indicate deep dry air layers which are progged to persist into early overnight hours. Severe threats are slim to none with these thunderstorms; lightning would be the only, if any, impact from evening and overnight convection. Late afternoon temperatures will reach mid- to upper 80s amid southerly flow ushering warm air into the Ozarks region. Winds will remain light through the evening before strengthening overnight, with gusts increasing through the early morning hours. 25-30mph gusts from the south can be expected by early Tuesday morning, with gusts increasing the further west you go. Tuesday: Models continue to track a wave that is coming ashore over the base of the western trough this morning through the Plains, pivoting to a negative tilt as it crosses Nebraska to along the Iowa/Minnesota border by 00z Wednesday. While the combination of instability and kinematics will support stronger convection north of the forecast area...the potential for severe weather will extend southward into the Ozarks. Convective inihibition of 50-100 J/KG at 18z will limit prefrontal convection, though the cap will weaken with afternoon heating, allowing convective development late in the afternoon. GEFS mean SBCAPEs at 00z climbs to near 3500J/kg along the Missouri/Kansas border and 0-6km bulk shear approaching 50 knots will lead to organized severe convection. There may be a period in which discrete supercells form in this high instability; however, considering anticipated hodograph relative to line movement, this period would be limited with the resultant line of storms moving through the forecast area. As for impacts - the high instability combined with h700-h5 lapse rates around 8C/km suggest a period of very large hail will be possible over west central MO before the transition occurs. The supercell tornado threat is lowered by the southwest winds though 0-1km CAPE/shear will need to be monitored for any storms that form out ahead of the line...followed by primarily a damaging wind threat for much of the CWA. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Issued at 215 PM CDT Mon May 20 2024 Tuesday Night - above mentioned convection will continue to track across the forecast area overnight. Storm mode will likely be transitioning from discrete cells to line segments. Wednesday through Thursday - while an outflow boundary from overnight convection may initially serve to become the effective front south of the region...the actual frontal boundary associated with Tuesday`s wave will lag behind as the associated upper wave pivots northward into Canada. Severe convection is anticipated to redevelop along and ahead of either the effective or actual front with the latter leading to the potential vicinity of I-44 early...exiting southern MO late afternoon into early evening. The southwest to northeast orientation of the upper flow combined with the stalling of the front will also potentially set the stage for training storms and excessive rainfall into Thursday. Precipital water will increase to 1.5-1.75" which is 1-2 standard deviations higher than normal for late May. Will need to watch the range of model QPF output though at this point the NBM is generally depicting a 25% chance for more than 1.5" and a 10-15% chance 3" of rain over areas south of I-44 to the Arkansas border from Wednesday-Thursday, on top of earlier rains this week, setting the stage for flooding. Friday into the Holiday Weekend - Southwest to westerly orientated upper stream will continue, and while the main stream of shortwave energy shifts toward the Canadian border resulting in weakening upper flow, successive slow moving frontal boundaries look to periodically serve as the focus for convection. Thus, there will be a daily chance for rain, though not all areas will see rain each day. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1221 PM CDT Mon May 20 2024 Scattered low cumulus deck prevails over Joplin and continues to build upstream, and this deck is beginning to push into the Springfield area and will linger through the afternoon. Southerly winds on the magnitude of 10ish knots will prevail as well, veering a bit as remnant mesoscale circulations to the north wind down before returning to a southerly direction this evening. Winds will be gusty along KS/OK/AR state lines into the overnight hours, with gusts near 25kts starting around sunset and getting stronger overnight, especially near JLN. Low-level wind shear concerns for a brief period between 09Z-13Z at SGF/JLN as a low-level jet pushes into the Plains. Showers and storms will be possible tonight, with little to no impacts to TAF sites expected as the storms should stay to the N/NE of all sites. Winds will get gusty going through the day Tuesday, with gusts as high as 45kts along the KS/MO border, progressively decreasing to the east but remaining strong (between 25-35kts at TAF sites). As the next disturbance moves into the region, some low-level clouds are expected to develop; flight category degradation is not expected by 18Z Tuesday, though this may be fine tuned in future updates. && .CLIMATE... Issued at 100 PM CDT Wed May 15 2024 Record High Temperatures: May 20: KSGF: 90/1964 KJLN: 92/1956 KUNO: 89/1964 May 21: KSGF: 91/1987 KJLN: 91/1987 Record High Minimum Temperatures: May 20: KSGF: 71/1902 May 21: KSGF: 70/1902 && .SGF WATCHES/WARNINGS/ADVISORIES... KS...None. MO...None. && $$ SHORT TERM...Camden/Runnels LONG TERM...Runnels AVIATION...Camden CLIMATE...Burchfield