109 FXUS64 KMOB 202326 AAA AFDMOB Area Forecast Discussion...UPDATED National Weather Service Mobile AL 626 PM CDT Fri Apr 20 2018 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION... 00Z issuance...Surface high pressure well north of of the forecast area will shift to over the East Coast overnight, bringing a shift in low level flow from northeasterly to easterly overnight, then southeast by the end of the forecast. With the shift in winds to easterly, guidance is advertising a slug of low level moisture (centered around 950mb) moving over the area beginning around sunrise. This will bring a drop in CIGs from general VFR to mid MVFR beginning around sunrise, the a rise back to VFR by 18z as the boundary layer deepens and the moisture layer mixes out. Am not anticipating any low end MVFR/IFR CIGs/VISBYs affecting operations with this package. /16 && .PREV DISCUSSION... /issued 353 PM CDT Fri Apr 20 2018/ NEAR TERM /Now Through Saturday/...A shortwave upper ridge will move eastward across the central Gulf Coast through Saturday. This will allow for a slight increase in high temps Saturday, while maintaining dry conditions. Meanwhile, southeasterly low level flow will increase through the day as a cold front begins to approach from the west. Moisture levels are expected to increase enough near the coast for the possibility of a few light showers by the afternoon. Lows tonight will range from the upper 40s and low 50s inland to upper 50s along the coast. Highs on Saturday will climb into the low to mid 70s. /13 SHORT TERM /Saturday night Through Monday night/...An upper level low over the south Plains pushes east into the lower Mississippi River Valley and Mid South Saturday night into Sunday. Upper level height falls ahead of this system, in conjunction with upper diffluence associated with the left exit region of a jet max rotating through the base of the trough, will serve to increase deep-layer ascent along and ahead of an attendant surface front. A quickly moistening warm sector ahead of this front should see enough destabilization (~500 J/kg MLCAPE) to support showers and thunderstorms, with the best potential for thunder coincident with the greatest forcing and instability along the front and near the coast. Veering deep layer wind profiles and effective bulk shear magnitudes at or above 40 knots could allow any stronger cells to become better organized and capable of producing severe weather. Given the uncertainty in available instability, however, only a marginal threat is in place at this time. Generally expecting rainfall amounts of up to 2 inches with this system, with local amounts up to 3 to 4 inches not out of the question. These totals may not appear heavy at first glance, but it should be noted that those who received significant rainfall with the previous system (i.e., interior southeast Mississippi and southwest Alabama) are likely to be more vulnerable to flooding than normal, as this additional rainfall only exacerbates the already elevated rivers and streams. The cold front pushes through Sunday night into early Monday as the upper low weakens and pushes off to the east, eventually settling over the southeastern states Monday and Monday night. The passage of this front should mark the end of precip for most, particularly near the coast. Farther inland, could see some light showers continue throughout the day Monday in the wraparound region of the surface low. /49 LONG TERM /Tuesday Through Friday/...The upper low stalls over the southeastern states as another quick-hitting shortwave rotates through the region to start the long term period. Lingering wraparound moisture over inland and western portions of the area should be enough to squeeze out some showers as this shortwave passes through Tuesday. The first in a series of troughs digs from central Canada southeast into the upper Mississippi River Valley and Midwest on Wednesday, helping to finally push that stalled upper system over the southeastern states east and away from the area. As the former trough continues to dig into the eastern CONUS, it pushes another cold front southeast towards the Gulf coast. We see a bump in rain chances along and ahead of that front Wednesday night before it passes through and brings dry conditions Thursday. Dry weather will be short lived, as the next in the series of upper troughs digs into the upper Midwest Thursday night. This pushes yet another front towards the area, with moisture quickly returning and rain chances increasing Friday ahead of the front. /49 MARINE...A moderate easterly flow tonight will increase on Saturday as a cold front approaches from the west. A moderate to sometimes strong southeast to south flow develops Saturday night ahead of the front. Winds become westerly in the wake of the front by Monday, with a light to moderate west to northwest flow then continuing into the middle part of mid next week. /13 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...None. FL...None. MS...None. GM...None. && $$ This product is also available on the web at: http://weather.gov/mob