Port Aransas to Matagorda Ship Channel Marine Forecast
|Rest Of Today...East Wind 20 To 25 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Showers And Thunderstorms.|
|Tonight...Northeast Wind 15 To 20 Knots Becoming Northwest 20 To 25 Knots After Midnight. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. Showers And Thunderstorms In The Evening, Then A Slight Chance Of Showers And Thunderstorms After Midnight.|
|Sunday...North Wind 15 To 20 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet.|
|Sunday Night...North Wind 20 To 25 Knots. Seas 5 To 7 Feet With Occasional Seas Up To 9 Feet.|
|Monday...North Wind 20 To 25 Knots. Seas 5 To 7 Feet With Occasional Seas Up To 9 Feet.|
|Monday Night...North Wind 15 To 20 Knots Becoming Northeast 10 To 15 Knots After Midnight. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet.|
|Tuesday...East Wind 5 To 10 Knots Shifting Southeast In The Afternoon. Seas 2 To 3 Feet.|
|Tuesday Night...South Wind 10 To 15 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. A Slight Chance Of Showers.|
|Wednesday...Southeast Wind 10 To 15 Knots Shifting Northeast In The Afternoon. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. A Chance Of Showers.|
|Wednesday Night...North Wind 10 To 15 Knots Increasing To 15 To 20 Knots After Midnight. Seas 6 To 8 Feet With Occasional Seas Up To 10 Feet. A Chance Of Showers.|
| Synopsis for Middle Texas coastal waters from Baffin Bay to Matagorda ship channel - GMZ200|
1219 PM CST Sat Nov 28 2020
Numerous showers and thunderstorms are expected today. A few storms may be strong with gusty winds, frequent lightning and heavy rainfall. Away from thunderstorm activity, prevailing moderate to strong onshore flow is expected this afternoon, then weaken this evening in advance of a cold front. The front will move offshore tonight with moderate to strong offshore flow developing in response. Rain chances will diminish from west to east Sunday morning as drier air arrives. A surge of even drier air by Sunday night will maintain strong offshore flow, before winds finally taper Monday night. There remains additional chances for showers from Wednesday through late week ahead of the next upper disturbance and cold front, but confidence in this system is low at this time. This front may again create strong offshore flow with higher seas from Thursday through Friday.
| Area Forecast Discussion|
National Weather Service Corpus Christi TX
1235pm CST Sat Nov 28 2020
Updated Waters again to hoist a Small Craft Advisory for the northern Coastal Waters, owing to wind nearshore, and wind/seas offshore. Expect the MSLP gradient over the Waters to persist, and possibly increase owing to upper jet dynamics. In addition, the tide level at Bob Hall Pier is increasing at a greater rate than the increase in the astronomical level, suggestive of possible Ekman forcing associated with persistent NE flow. However, unsure of coastal flooding given expectation of offshore flow tonight in response to the front.
Increased wind over the Waters to account for current and predicted (GFS/NAM/ECMWF (European Centre for Medium-Range Weather Forecasts) deterministic) meso/synoptic scale MSLP pattern/gradient over the region. Anticipate predominately Small Craft Exercise Caution conditions. Updated the CWF.
AVIATION... Showers and thunderstorms are expected periodically throughout the day across S TX. A few strong storms with gusty winds, small hail and heavy rainfall will be possible. The convection will lead to a mix of MVFR (Marginal Visual Flight Rules) and IFR conditions through the day, becoming primarily IFR this evening. A surface trough/cold front across the area today will lead to north to northwest winds across the western areas and east to northeast winds across the eastern areas this afternoon, becoming predominantly north to northwest tonight as the cold front exits the region. The convection is also expected to end late tonight into early Sunday morning from west to east as drier air filters across the area from the west. VFR conditions are expected by early Sunday morning across LRD and COT.
SHORT TERM (Today)... Showers and a few thunderstorms are filling in across S TX this morning per radar. This is in response to embedded weak short waves tracking east-northeast across the region and combining with deepening moisture. The heavier rainfall has generally been across the northern portions of the CWA this morning. The better instability per LAPS analysis is currently across the southern coastal bend where minimal precipitation has occurred so far, but the rainfall should increase in this area as well, over the next 2-4 hours.
A weakening outflow boundary that moved south across the area this morning has led to a surface trough along the coast. The cold front has become less defined as a result due to northeast winds across S TX. However, the colder and drier air will be lagging behind the windshift/trough axis.
The main upper low is moving eastward toward the TX Panhandle and should be crossing the panhandle throughout the day. This will help deepen the surface trough which models prog to occur through the morning and early afternoon, but differ somewhat on just where the trough axis will be located as it waffles across the area later this morning. The overall consensus is that the trough axis should be east of the Brush Country.
A strong upper jet will shift farther southeast and place the RRQ across S TX by late morning into early afternoon. This will provide good upper support for thunderstorms. Weak instability will remain generally across the Coastal Bend with the surface trough providing low level support. The trough is forecast to lift northeast by late afternoon, with colder, drier air building across S TX from northwest to southeast in its wake.
As for the rainfall, the heavier rainfall is forecast to be across the Victoria Crossroads, but could also extend farther south across the Coastal Bend due to the trough. The heavier rainfall may train across eastern portions of S TX which may lead to localized flooding today. Total rainfall amounts today through tonight are expected to range from 1/2 an inch along the Rio Grande to 1 to 2 inches across the eastern portions of the area. Highest amounts are expected to be across the Victoria Crossroads and along the coast with around 2 inch amounts expected. Isolated higher amounts are possible, especially across the Victoria Crossroads where there is a slight risk of excessive rainfall. The slight risk of excessive rainfall extends into Houston's area. Given the dry soils, widespread flooding is not anticipated at this time, but localized flooding is possible.
LONG TERM (Tonight through Friday)... Tonight, the upper low over the TX Panhandle and its attendant trough axis will glide east and in the process accelerate the cold front offshore ahead of markedly drier northerly breezes. However, this drying will initially be confined to a shallow near- surface layer all the while the right rear quadrant of a mid and upper jet streak will maintain some lift likely resulting in at least some light post-frontal showers. Barring a few rogue showers in our southern coastal counties early Sunday morning, this window for post- frontal precipitation should be closed as surface ridging and low theta-E invades the region. What's most dramatic is that exceptionally dry air is set to arrive on Monday from an even stronger surface high. With surface dewpoints cratering into the teens and 20s under deep moisture deficits, models show PWATs (Precipitable Waters) as low as 0.07 inches which is uncommon for this region. This combined with light northerly winds Monday night is looking to set the stage for a widespread freeze for most of our inland counties.
Once dry surface ridging departs on Tuesday, moist isentropic ascent unfolds ahead of the next upper low to our northwest. The behavior of this low remains at odds among the models, but in general the blocky synoptic pattern would tend to favor a slightly slower and more amplified low evident on the CMC and ECMWF, although the ECMWF is a bit of an extreme outlier with its N-S moist axis about 100+ miles west of the CMC. Models are also probably too bullish in moistening the previously bone-dry column, so saturation could easily be delayed in many areas which is why we'll continue to undercut the NBM's generous PoPs. Another cold front will sweep south at some point Wednesday or Thu as the upper low shifts across the Red River, but uncertainty in this front's timing warrants at least some low shower chances as late as Thu before drying out thereafter.
Scattered to numerous showers and thunderstorms can be expected today. A few storms may be strong with gusty winds, frequent lightning and heavy rainfall. Outside of the thunderstorms, a weak to moderate onshore flow can be expected ahead of a cold front. The cold front will move offshore this evening with moderate to strong offshore flow and Small Craft Advisory conditions developing overnight. Rain chances will diminish from west to east on Sunday morning as drier air arrives. A surge of even drier air by Sunday night will maintain strong offshore flow, before winds finally taper Monday night. There remains additional chances for showers from Wednesday through late week ahead of the next upper disturbance and cold front, but confidence in this system is low at this time. This front may again create strong offshore flow with higher seas from Thursday through Friday.
NOAA Corpus Christi TX Office: Watches - Warnings - Advisories
TX...None. GM...Small Craft Advisory until 6pm CST this evening For the following zones: Coastal waters from Port Aransas to Matagorda Ship Channel out 20 NM...Waters from Port Aransas to Matagorda Ship Channel from 20 to 60 NM.