Area Forecast Discussion
Issued by NWS Houston/Galveston, TXVersions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
618 FXUS64 KHGX 130021 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 621 PM CST Fri Mar 12 2021 .AVIATION... VFR cigs expected to start out the TAF period but a gradual lowering of ceilings is expected around 06z with a mix of MVFR and IFR ceilings between 06-12z as low level moisture deepens under a low level cap. Conditions should mix out between 15-17z Saturday with generally VFR ceilings over the area. Water temp is now 64 and dew points are 65 at KGLS so there is some potential for sea fog but not enough of a signal to hit the KGLS TAF hard with fog overnight. 43 && .PREV DISCUSSION... /ISSUED 306 PM CST Fri Mar 12 2021/ SHORT TERM [Through Saturday]... Slightly drier llvl air, which has allowed for more breaks of sunshine and warmer highs today, will continue to filter in from the Gulf overnight. This along with lower wind speeds and a pcldy start to the night, should allow for slightly cooler lows tonight compared to the previous few. Still anticipate the lower clouds to fill back inland (along with some sea fog closer to the coast), but that should occur a bit later. Base of upper trof over southern Ca/NV will make its way across the Desert Southwest and into the Southern Plains by Sat evening. Could see some spotty afternoon shra, but much better precip chances arrive for most of the area late Sat night & Sun. 47 LONG TERM [Saturday Night Through Friday]... Getting tired of the same old weather pattern we`ve had throughout most of the week with above normal temperatures and an overall feel of mugginess? Well we do have a couple of cold fronts to talk about that will offer some relief, but the first one is not all that impressive. Before that though, we`ll have to make it through another mild night on Saturday with lows in the low-to-mid 60s. For our far northwestern counties, temperatures will be able to drop into the mid 50s as the first cold front passes through right around sunrise. As previously mentioned, this cold front won`t offer much in the form of a cool down since it is of Pacific origin, but it will bring a line of showers and thunderstorms as it passes through on Sunday morning/afternoon. There will be plenty of moisture ahead of the front with PW values ranging from 1.4" to 1.6" combined with suitable low-level convergence along the frontal boundary. SPC has backed off on the severe risk for the area on Sunday, likely due to the lack of upper-level support as the jet streak will be too far north and west to provide divergence aloft. Instability is also lacking too, but should be enough for at least a few rumbles of thunder. High temperatures on Sunday will run on the cool side with highs in the upper 60s/low 70s. Clouds begin to clear out for the northern half of the CWA on Sunday night, which will be enough to get radiational cooling to push these areas down into the upper 40s. Partly to mostly cloudy skies remain for the southern half as the front becomes washed out along the coast, so lows will be a bit warmer in the low-to-mid 50s. The front comes back ashore as a warm front by Monday night, so rain chances will linger off the coast. The heat and humidity makes a comeback early next week with 850mb temperatures creating suitable conditions for highs in the 80s for Monday and Tuesday. With increasing cloud cover and strengthening WAA on Monday night, leaned overnight temperatures a bit higher than guidance with lows in the upper 50s/low 60s. Rain chances pop up once again on Tuesday afternoon as a few models are hinting at warm air advection showers/storms ahead of the next cold front. Another 500mb low will swing down from the Four Corners region and develop a surface low near the OK/TX panhandles. Models are in agreement that there will be a lot more instability in place, but slightly disagreeing on timing with the ECMWF about 6 hours faster than the GFS with FROPA on Wednesday morning/afternoon. The ECMWF also dries out the area quicker than the GFS which would mean a quicker drop off in PoPs. In short, expect another line of showers and thunderstorms to accompany Wednesday`s front and cooler temperatures behind it. With clouds clearing out and dry air filtering in going into Wednesday night, we will be in for a pleasant second half of the work week with temperatures becoming more seasonal with highs in the low 70s, and lows in the 40s/50s. Temperatures over the weekend will depend on how quickly surface high pressure pushes off to the east and places the region back into onshore flow. Batiste MARINE... Anticipate another round of sea fog to develop overnight...with the potential for the locally dense variety possible generally east of Sargent. It`ll retreat back into the Gulf during the morning hours Sat. Rinse/repeat Sat night. Otherwise, light-moderate onshore winds will gradually increase Saturday night ahead of an approaching storm system. A combination of SCEC/SCA flags will probably be required into Sunday morning. The tail end of a weak Pacific front will make its way west-east into the coastal waters Sunday afternoon and evening. Winds will briefly switch to an offshore direction as this occurs, but southeast winds should quickly resume Monday. Light-moderate onshore winds then prevail until another front pushes through later Wednesday. A Spring Break reminder if going to the beach: swim near a lifeguard. Stay away from rocks, jetties, piers where there are always rip currents. Don`t swim on the eastern & westernmost tips of Galveston Island where there are also hazardous currents. 47 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 64 80 56 67 48 / 10 10 50 70 10 Houston (IAH) 64 80 65 72 52 / 0 10 30 70 10 Galveston (GLS) 65 74 64 71 60 / 10 10 10 60 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ Discussion...99 Aviation/Marine...99
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