Area Forecast Discussion
Issued by NWS Little Rock, AR
Issued by NWS Little Rock, AR
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361 FXUS64 KLZK 302014 AFDLZK Area Forecast Discussion National Weather Service Little Rock AR 314 PM CDT Thu May 30 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (This evening through Saturday) Issued at 311 PM CDT Thu May 30 2024 Fairly quiet across the FA this aftn, but cont to monitor ongoing convection slowly apchg fm OK and NE TX. A stationary bndry was situated close to SW AR, where sfc dewpoints were arnd 70. Drier air was noted further to the NE ovr our FA, with corresponding readings in the mid/ upper 50s. Basically, an unsettled weather pattern is in store for the area in the coming days. Several upper SWT`s are progged to traverse the area into Sat, resulting in several rounds of convection affecting the FA thru Sat. Timing and placement of smaller scale boundaries always tend to lessen fcst confidence is these situations regarding temps and PoPs. CAMS cont to show the aforementioned convection working into western AR this evening, but shows some signs of weakening with loss of daytime heating. However, additional storms are fcst to impacts OK and TX later tngt, with some of this activity likely affecting much of the area heading into Fri. Again, depending on meso-scale features, there is the potential for some strong/severe storms on Fri. Rain chcs wl cont on Sat, with a brief break possible Sat ngt, but that wl be short-lived to close out the weekend. Heavy rainfall wl cont to be a concern for localized flash flooding. However, opted to hold off with any Flood Watches for now, but wl cont to monitor. && .LONG TERM... (Saturday Night through next Thursday) Issued at 311 PM CDT Thu May 30 2024 In general west-northwest flow aloft will be in place over the central CONtinental United States (CONUS) from Saturday night through Wednesday. In the absence of a powerful upper level trough or ridge, shortwave troughs will generally provide the perturbations that cause the geostrophic flow aloft to alternate between pure westerly and shifts to northwesterly flow aloft. These shifts are important because they will have a cascading impact on surface weather conditions east of the Rockies to the Mississippi River. When the flow aloft is oriented westerly, as the westerly flow moves from the high terrain of the Rockies to the lower terrain of the plains, the atmospheric column expanding in depth will cause a surface trough to develop over the higher plains east of the Rockies. This is due to the conservation of potential vorticity which effectively creates surface troughing due to the atmosphere moving from a compressed to expanded vertical state simply due to elevation change alone. With westerly flow aloft causing cyclogenesis over the high plains, periods of northwest flow aloft will drive weak/Pacific type cold frontal boundaries southeast, providing synoptic scale lift east of the surface cyclones or troughs that develop during conditions of westerly flow aloft. The western troughs will cause south or southeasterly low-level flow to set up over Arkansas pumping moisture rich Gulf of Mexico air north across the state. Because this period exists in early June, the sun angle is just about as high as it gets over the CONUS leading to extremely efficient heating each day. The positive moisture flux combined with the efficient daytime heating will be consistent drivers of thunderstorm energy across the state Sunday through Wednesday. Everytime one of the pacific type cold fronts interacts with this energetic airmass, it will kick off a line of thunderstorms that will continue downstream into the axis of hot and humid air. As a result, this type of pattern is well known to send multiple linear mesoscale convective systems (MCSs) across the central CONUS this time of year. Each linear MCS will bring with it a threat for damaging winds and at least a marginal threat for hail and quick spin up tornadoes. Localized flooding is also possible, but widespread flooding is not common because these types of storm systems tend to move and don`t sit in one place all that long. This cycle of linear MCS, reset the atmosphere with southerly winds, just in time to allow another linear MCS roll through will continue throughout the extended forecast period will continue through Monday when a stronger upper trough digs southeast over the western Great Lakes region driving a Pacific type cold front well south of Arkansas interrupting the moisture reloading cycle of this weekend through early next week. After Wednesday drier air will move across the state leading to a period of drier weather beginning Thursday and likely continuing into next weekend. Cavanaugh && .AVIATION... (18Z TAFS) Issued at 1245 PM CDT Thu May 30 2024 VFR conds wl prevail this aftn acrs the FA. CU field wl cont to dvlp from aftn heating, esp acrs the SW part of the area where higher sfc dewpoints reside. CAMS cont to show the remnants of ongoing storms to the west of AR, could affect some of the central terminals by this evening. Opted to go with VCTS at these sites for now and see how things play out. MVFR conds wl return to most areas later tngt and Fri as additional convection impacts the FA, with some IFR conds possible Fri mrng. .LZK WATCHES/WARNINGS/ADVISORIES... None. && .PRELIMINARY POINT TEMPS/POPS... Batesville AR 64 76 66 82 / 30 70 70 60 Camden AR 68 81 66 83 / 50 90 70 60 Harrison AR 62 73 63 80 / 40 80 70 30 Hot Springs AR 66 78 66 84 / 50 90 70 50 Little Rock AR 69 80 68 85 / 60 80 70 60 Monticello AR 69 83 68 84 / 30 70 70 80 Mount Ida AR 65 78 65 85 / 60 90 70 50 Mountain Home AR 62 73 64 80 / 30 80 70 40 Newport AR 66 78 68 83 / 20 60 70 70 Pine Bluff AR 68 81 67 84 / 40 80 70 70 Russellville AR 67 78 66 84 / 50 90 70 40 Searcy AR 65 76 66 83 / 50 70 70 60 Stuttgart AR 69 80 68 83 / 50 70 70 70 && .LZK WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...44 LONG TERM....66 AVIATION...44