FXUS64 KHGX 120932 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 332 AM CST Thu Dec 12 2024 ...New SHORT TERM, LONG TERM, AVIATION, MARINE... .SHORT TERM... (Today through Friday Night) Issued at 311 AM CST Thu Dec 12 2024 Surface high pressure has moved off to the east. As low level southeast winds resume, look for the cloudiness seen off the coast on satellite pictures to make their way back inland during the afternoon and evening hours. Prior to that, mostly sunny skies will allow morning temps in the 30s to rebound into the 60s. Cloudy and warmer conditions tonight with the column below 700mb becoming fairly saturated. Some disturbances in the quasi-zonal flow aloft are forecast to push thru the area late tonight and Friday morning. Look for some associated scattered pockets of -ra/dz across the area as it passes. Friday night, increasing low level jet will continue to transport Gulf moisture into the area and maintain a saturated 700mb-surface column. Scattered -ra/shra look like a decent bet areawide. West and northwest parts of the CWA look to be best positioned under the fetch of deepest moisture and where we should probably see the better overall coverage. In addition, a mid level trof will be passing across the Rockies and into the central Plains. Most of the forcing with this should remain to our north, but some tail end spokes of vorticity may pass close enough to our northern zones to further coverage there as well - especially heading into the late night hours. 47 && .LONG TERM... (Saturday through Wednesday) Issued at 311 AM CST Thu Dec 12 2024 An upper level trough is still expected to fill NE through the Mid/Upper MS River Valley on Saturday, pushing a weak cold front into the vicinity. The front should stall out over north/central Texas before reaching our area, evident by stronger agreement in long range models & ensembles. This will keep SE Texas on the warmer side with highs in the upper 60s/upper 70s with lows in the mid 50s/mid 60s. PWs 1.2-1.5 inches, forcing from the trough and low level confluence ahead of the front should bring showers and isolated storms during the day, with rain chances greatest in areas north of the I-10 corridor. Areas along the coast should be on the lookout for sea fog, especially as observations and model guidance have shown growing confidence in it's development. Water temperatures by in large sit around or under 61 degrees across much of the nearshore waters and bays. Surface dewpoints should have already risen into the 60s by this point, with ensemble means putting them solidly around the mid 60s or higher along the coast. E/SE flow at the surface should provide a favorable flow regime for advecting these warmer dewpoints over the cooler shelf waters. Wind speeds early on Saturday start off around 10-15 knots, enough to possibly limit sea fog from becoming dense. Though, winds should fall under 10 knots by that afternoon as the gradient weakens, increasing the risk of dense Sea Fog for that evening and Sunday morning. Coastal MOS products and LAMP guidance back up the notion of sea fog developing on Saturday as well. SREF vis probabilities add further confidence to this forecast, depicting an increasing chance of visibility <1 SM over the coastline from Saturday through Sunday morning. Mixing, afternoon heating and increasing winds should help improve visibility from any fog for inland areas during the daytime on Sunday. Less so over the bays and nearshore waters, largely in part due to ample cloud cover overhead (indicated by deep moisture under 850mb in dynamic ensemble soundings). Onshore flow and continued WAA should bring highs up into the 70s, though rain chances will be generally lower as a result of less forcing available. Sea fog could develop/fill in again Sunday night through the morning hours of next week. Odds of sea fog (and dense sea fog) may be slightly higher due to lower rain chances and thus less mixing. On Monday another upper level trough should sweep across the North/Central Plains, pushing another cold front into SE Texas late Monday afternoon/early Tuesday (ending the threat of sea fog). This will bring another cool down on Tuesday with highs dropping into the 60s. Larger model & ensemble spread emerges by this point in the forecast, adding greater uncertainty. The NBM and a few long range ensembles suggest a marginal warm-up during the day on Wednesday as the boundary lifts north as a warm front. This should be short lived, as models suggest that another upper level trough will dig through the Plains on Wednesday, pushing another cold front through during the early morning hours of Thursday. 03 && .AVIATION... (12Z TAF Issuance) Issued at 311 AM CST Thu Dec 12 2024 VFR conditions will prevail into the late evening hours. Southeast winds will resume and increase to 10-15kt with some gusts around 20kt possible later today. We will see some 4000-5000ft ceilings move in from the Gulf as the afternoon progresses...trending downward into MVFR territory from south-to-north after 9z or so. 47 && .MARINE... Issued at 311 AM CST Thu Dec 12 2024 Onshore should return today, strengthening to around caution levels later tonight as rain chances return. Patchy sea fog may return early Friday morning to areas around Matagorda bay, though stronger winds should prevent fog from becoming thick. The threat of sea fog expands to the rest of the bays/nearshore waters Friday evening, becoming more likely during the nighttime hours (5pm-11am) over the weekend as winds weaken. A cold front will push off the coast Monday night/early Tuesday morning, bringing northernly winds and ending the threat of sea fog. 03 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 65 52 67 62 / 0 10 20 40 Houston (IAH) 65 52 67 63 / 0 0 20 30 Galveston (GLS) 64 59 68 65 / 0 20 30 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...47 LONG TERM....03 AVIATION...47 MARINE...03