####018006539#### FXUS63 KFSD 241110 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 610 AM CDT Wed Apr 24 2024 .KEY MESSAGES... - Chances for rain and storms return late Thursday and persist through the weekend. Strong to severe storms are possible on Friday. - Beneficial rainfall is possible Thursday night, with a 50-80% chance for exceeding a half an inch of rain. && .DISCUSSION... Issued at 342 AM CDT Wed Apr 24 2024 Today will be a quiet day across the area as a surface ridge slowly pushes through the Northern Plains and into the Upper Midwest. Light winds will begin the day out of the east and slowly turn southeasterly throughout the day. Soundings do show a small moist layer between 700-600 mb which is expected to result in some mid level clouds. This mid level cloud deck will develop over south central South Dakota and push eastwards throughout the day. With dry low levels beneath the cloud deck, do not expect any rain to reach the surface. This mid level cloud deck will keep high temperatures just a touch cooler with highs warming to the 60s this afternoon. The near seasonal temperatures and light winds will make for a solid day for outdoor activities. Get out there any enjoy it if you can! Elevated southeasterly winds will persist through the night and keep low temperatures on the mild side, only falling down to the 40s to perhaps 50 degrees F. A strong upper level wave will begin to eject into the Plains states on Thursday. The best lift with the wave looks to stay south and west of the area during the daylight hours, keeping conditions mostly dry. High temperatures will remain in the 60s but dew points will slowly moisten to the 40s. Southeasterly winds will remain gusty with gusts as high as 30-40 mph. As the wave begins to encroach on the Northern Plains, warm air advection (WAA) will strengthen in response to an intensifying low level jet (LLJ). This will set the stage for increasing precipitation chances Thursday evening and night. The WAA will encounter an elevated warm front around 850 mb which should allow for weak elevated convection to develop. Strong to severe storm chances Thursday night looks low (<30% chance) as instability will be lacking with only a few hundred J/kg of CAPE. The other aspect to Thursday night is that 850 mb moisture transport will increase due to the strong LLJ in place, which will set the stage for beneficial rainfall. Ensembles have slightly increased their probabilities, now up to a 50-80% chance for exceeding a half an inch of rain Thursday night. The upper level wave pushes into the Northern Plains on Friday, bringing the potential for strong to severe storms with it. Questions still remain regarding the severe storm potential as overnight storms could limit diurnal destabilization during the afternoon hours via storm outflow cooling the low levels and cloud cover. Along with potential destabilization issues, medium range guidance continues to vary how far north the surface warm front gets. If the warm front is able to push into the Missouri River Valley, then severe storms may be possible. If not, perhaps elevated storms will be possible. The deterministic Euro, GFS, and NAM are generally in support of stable low levels and thus the potential for elevated convection. However, cluster analysis reveals that the most favored cluster has the warm front getting into the Missouri River Valley and about 1,000 J/kg of CAPE and minimal convective inhibition (CIN). Latest hi-res ensemble does show convection firing along the warm front as well. Despite some CIN in place, think that the ensemble develops convection due to strong positive vorticity advection (PVA) from the wave finally pushing into the forecast area. On top of the PVA, an upper level jet streak will reside over the surface warm front which could result in a coupling of the frontal circulation and the jets indirect thermal circulation via the lift in the left exit region. Will continue to monitor severe storm trends. Aside from storm chances, Friday will continue the trend of near seasonal high temperatures in the 60s and perhaps 70s, again depending on cloud cover. Dew points will moisten into the 50s which will make for the first humid day across the area this Spring. With the previously mentioned LLJ remaining strong throughout the day, gusty southeasterly winds will continue with gusts up to 30-40 mph. Low temperatures will only fall to the 40s and 50s overnight. Another upper wave will eject into the Plains on Saturday brining renewed chances for rain and storms. This chance for storms will depend on where the surface front sets up. As of now, ensembles keep the front southeast of the forecast area. This can still change so trends will be monitored but the fronts position suggest a minimal chance for severe storms on Saturday. Sunday will be a similar day as the base of the upper level trough will push through the region. Severe storm chances will again depend on the waves evolution and surface front location. Ensembles do show nearly a 100% chance for exceeding a tenth of an inch of liquid QPF over the weekend, but with details uncertain, have stuck with model blended PoPs. High temperatures look to remain in the 50s and 60s for the weekend. Dry conditions look to return on Monday as the wave lifts north and subsidence prevails on the wave's backside. The dry conditions look to persist into the middle of next week along with warmer high temperatures, potentially into the 70s as supported by the ensembles. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 610 AM CDT Wed Apr 24 2024 VFR conditions are expected for the TAF period. Light and variable winds will slightly strengthen out of the east/southeast today with speeds between 5-15 knots, strongest west of the James River. A mid level cloud deck will develop across central South Dakota and push eastwards through the day, based around 10,000 ft. Southeasterly winds further strengthen this evening and night with gusts up to 15- 25 knots to end the TAF period. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...Meyers AVIATION...Meyers ####018006516#### FXUS63 KLBF 241113 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 613 AM CDT Wed Apr 24 2024 .KEY MESSAGES... - Thunderstorms possible tonight, mainly west and south. - Severe thunderstorms possible Thursday night over most of the forecast area. - Wetting rains expected Friday, and again on Sunday with a reprieve Saturday in between upper level systems. - Mainly dry and seasonal Monday into Tuesday. && .SYNOPSIS... Issued at 346 AM CDT Wed Apr 24 2024 H5 pattern tonight had a fairly low amplitude pattern across the CONUS. A shortwave trough of low pressure was present from the UP of Michigan south to around Chicago. Low amplitude ridging was present from northern New Mexico, north-northwest into Alberta Canada. Further west, a closed low was located approximately 600 miles off the central coast of California. Overnight, some mid and high level clouds, in association with a weak upper level disturbance, were traversing the central plains. Across southwestern Nebraska into northeastern Colorado and northwestern Kansas, some showers were present on radar with the bulk of this activity not reaching the surface. At the surface, weak high pressure was present over north central Nebraska overnight. Skies were partly to mostly cloudy with thicker clouds noted in SW Nebraska. Temperatures as of 3 AM CDT, ranged from 33 degrees at Broken Bow to 48 degrees at Imperial. && .SHORT TERM /THROUGH THURSDAY/... Issued at 346 AM CDT Wed Apr 24 2024 Surface high pressure will track into the upper Mississippi valley today. On the back side of the exiting high, southerly winds will increase, and by afternoon, we could see some gusts eclipse 30 MPH in the west per the latest NAM12 bufkit sounding data. With the increasing southerly winds this afternoon and favorable mixing, highs should reach into the lower 70s across the west. Further east with lighter winds, highs will be in the mid to upper 60s. Mid level ridging will become centered from the Texas Panhandle north into the western Dakotas tonight. Southerly winds will continue across the area, which will make for a mild night across the area with lows in the middle to upper 40s. Mid level warm air advection will increase this evening in the panhandle, transitioning to the east southeast overnight. This will lead to an increased threat for elevated thunderstorms tonight from the panhandle into southwestern and south central Nebraska. This convection will also be supported by a the development of a low level jet later tonight. ATTM, this appears to nose into south central Nebraska. The 06z HRRR, 00z NAM12 and the 00z GFS show an area of QPF from the panhandle into north central Kansas and south central Nebraska overnight. With this in mind and the degree of elevated forcing, will opt for some chance pops tonight in the before mentioned areas. As for the severe threat, steep mid level lapse rates are noted later tonight, particularly from southwestern Nebraska into northwestern Kansas. This would favor a hail threat. Confidence in this threat however is low as low level moisture return will lag this forcing, not expected to arrive until the day on Thursday. On Thursday, a strong mid level trough will lift into the southern Rockies. This feature will deepen a surface low over east central Colorado. During the day, increasing southeasterly winds will force low level moisture into the area along with a good chance for low level cloudiness Thursday. The latest high res models continue to hint at this low level cloudiness with it expected to persist into the afternoon hours. This will lead to cooler highs with readings in the lower 60s forecast for Thursday. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Issued at 346 AM CDT Wed Apr 24 2024 Based on the latest CAMS, convection should develop INVOF the dryline around 23z Thursday. This feature is expected to extend from Sterling Colorado, south to just east of the Colorado/Kansas border. As this activity lifts to the northeast into southwestern and south central Nebraska, very steep mid level lapse rates will support a large hail threat. There will also be a tornado threat, mainly across far southern portions of the forecast area, where low level helicities are most favorable. This may become enhanced further, if a warm front resides in the vicinity of this helicity max. The upper level trough and low will lift from northeastern Colorado, crossing Nebraska on Friday. This will be the best chance for wetting rains with this system. After quieter conditions Saturday, a second upper level trough will cross the area Saturday night into Sunday. With the track of this system, the main severe threat will be well east of the forecast area. However, another round of wetting rain appears likely as a nice zone of deformation precipitation develops across the area. The latest NBM probabilistic forecast for 72 hr precip. ending at 12z Sunday has an 85-95 percent chance of better than a half an inch of QPF across the entire forecast area. At a threshold of 1 inch, the probability drops off to 40 to 60 percent. In addition, we may need to watch the southwestern portion of the CWA as there is now a slight risk for excessive rainfall from 12z Saturday through 12z Sunday. Beyond Sunday conditions will dry out with highs Monday in the mid 60s and lower 70s and Tuesday's readings in the 70s. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 606 AM CDT Wed Apr 24 2024 VFR conditions prevail across western and north central Nebraska through the period. Winds will strengthen out of the southeast mid-morning with widespread gusts of 20 to 30 kts expected through this evening. Shortly thereafter, the gusty winds will begin to diminish, though still remaining breezy at generally 20 kts or less. SCT to BKN mid and high level clouds will continue through late in the period with ceilings beginning to fall to low-end VFR and potentially MVFR by 12Z as a stratus deck moves northward into southwest Nebraska. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Buttler SHORT TERM...Buttler LONG TERM...Buttler AVIATION...Viken