900 FXUS64 KLUB 302315 AFDLUB Area Forecast Discussion National Weather Service Lubbock TX 615 PM CDT Fri Jul 30 2021 .AVIATION... Isolated showers and thunderstorms should gradually diminish around sunset, with VFR expected through the forecast period. && .PREV DISCUSSION... /issued 246 PM CDT Fri Jul 30 2021/ SHORT TERM... Warm surface temperatures in the 90s and continued ample surface moisture have allowed convective temperatures to easily be surpassed this afternoon, resulting in the development of a nice field of cumulus across much of the CWA. Synoptically, an elongated upper ridge remains in place to our north, roughly extending along a line from SE Wyoming to NW Mississippi. The orientation of this ridge has placed the CWA under southeasterly flow aloft, with satellite analysis revealing a weak impulse within the upper flow moving over West Texas. This wave has acted to modestly increase midlevel moisture and lift in an otherwise weakly subsident environment, resulting in the development of isolated thunderstorms this afternoon. Instability is rather modest with SBCAPE generally less than 1000 J/kg and only weak shear present. Storms today will therefore remain of the unorganized pulse variety, although given decent moisture and skinny CAPE profiles will be capable of producing brief heavy downpours. Expect thunderstorm coverage to decrease this evening as the aforementioned upper wave moves west and daytime heating is lost towards sunset. Saturday will likely evolve in a similar manner to today as the upper ridge flattens and shifts southward. Surface flow will acquire more of a westerly component with the boundary layer drying out a bit as a result. Afternoon temperatures will be slightly warmer than today with deep mixing, allowing convective temperatures to be attained again. Despite a slightly drier boundary layer, midlevel moisture will remain in place and instability will be higher than today, resulting in another chance for isolated pulse-type thunderstorms during the afternoon. Any storms that do develop are expected to be quite limited in both coverage and duration with brief downpours possible. Outside of any convection, expect seasonably hot temperatures under partly cloudy skies. /DWK LONG TERM... Long term forecast continues to focus on the timing of the front for this weekend and continued chance for precipitation through next week. By Sunday morning upper level ridging will be in place across the Intermountain West with troughing across the eastern U.S. This trough will be responsible for sending a cold front through our area however model guidance continues to vary between late Saturday night and Sunday afternoon with frontal passage timing. The timing of this boundary will have impacts on precipitation chances during the Saturday night and Sunday time period as well as afternoon high temperatures for Sunday. Ahead of this front moisture will be on the increase with PWATs generally climbing above 1.5" area wide with some spots exceeding 2". This will set the stage for the potential for heavy rainfall with the front especially if the later solutions end up being correct. This front will also usher in cooler temperatures behind it with temperatures slightly cooler than average for this time of year. The upper level pattern will not change much for next week which will keep our area within northwest flow aloft. Surface winds will become southeasterly for much of next week which will help to keep moisture in place across the region and should lead to monsoonal type convection most afternoons. Additional precipitation chances may be possible during the evening hours as convection moves into the region from the higher terrain of New Mexico. With the subtle hints at forcing this far out it is hard to lock in exact windows of when the greatest precipitation chances will be so maintained ensemble PoP values at this time. With troughing remaining close to the region and the chance for precipitation temperatures should remain near to slightly below average for this time of year for much of next week as well. /WCI && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 55/99/99