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
000 FXUS64 KHGX 010536 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 1136 PM CST Thu Dec 31 2020 .AVIATION [06Z TAF Issuance]... MVFR ceilings remain for most of our TAF sites besides our coastal sites which have VFR conditions. Conditions overnight improved to MVFR faster than originally predicted and that pattern may continue, however keeping MVFR/VFR conditions for now. For our northernmost terminals, MVFR ceilings will remain throughout the TAF period, but they may briefly switch back and forth between IFR and VFR. Sites south of IAH are expected to reach IFR conditions near 09Z but remain gusty until drier, and more calm NW winds push in by the afternoon. KBL && .PREV DISCUSSION /Issued 605 PM CST Thu Dec 31 2020/... .DISCUSSION... .SHORT TERM [Through Friday Night]... Showers and thunderstorms are moving slowly out of the area this afternoon. As the low tracks from southwest to northeast, the associates cold front will drag along with it. Areas of training showers and storms are still a possibility in the eastern counties as the frontal boundary makes its way through the area. Radar is showing the end of the showers in the southwestern counties and will continue to progress through the afternoon with showers ending in the Greater Houston area around 3-4pm and exiting the northeastern CWA around sunset. In the wake of the front, westerly winds will begin to shift more northwesterly, bringing in drier and cooler air along with mostly clear skies through the night. Temperatures are expected to reach the mid 30s west of I-45 and in the low to mid 40s east of I-45; the main driver of this being the amount of time with cloud-free sky, allowing more radiational cooling. .LONG TERM [Saturday Through Thursday]... More cold/dry weather will be on tap as high pressure lingers over the region Sat night/Sun. As this high begins to drift east, winds will be slowly shifting to the SW (Mon) and then to the S/SE (Tue). This return of onshore winds should allow for the return of warmer temperatures and increasing low-level moisture. Rain chances could begin as early as Tues night in the form of WAA-type showers along the coast (as the gradient tightens in response to the falling low pressure over the Southern Plains), but the better chances will be on Weds with the arrival of the next cold front. Another cool down with drier air is then progged for SE TX for the rest of the week. .MARINE... Winds are veering from southeasterly to northwesterly this afternoon as low pressure begins to pull away from the area, leaving our waters in the wake of a cold front. Winds are also strengthening as post-frontal winds kick in, prompting a Gale warning on the Gulf (and a small craft advisory on the bays) through tonight. Though not issued yet, a small craft advisory is also going to be needed tomorrow on the Gulf as winds and seas gradually diminish. Additionally, the gusty northwest winds will prompt a low water advisory for at least one low tide cycle tomorrow morning. Winds should be weak enough by Saturday morning to preclude the need for a low water advisory through that tide cycle, but it will be close - and if winds are slow to die down, could possibly be needed for one more day. Beyond tomorrow, look for winds and seas to become more quiescent, with onshore flow returning by Monday afternoon at the latest. Light to moderate onshore flow is expected to prevail until the next front in the middle of next week. .HYDROLOGY... Heavy rain has exited to the east, but a handful of area streams and rivers are approaching or into flood stage. The San Bernard River at East Bernard is already in flood, with downstream points likely to follow as water is routed downstream. Additionally, a couple points on channels draining into Matagorda Bay are forecast to reach flood stage. Finally, while most of the bayous in and around Harris County have stayed in their banks, there are some locations where this is not the case, and flood warnings have been issued to indicate where minor flooding is most likely. These are along Spring Creek from Field Store to Hegar Road, along with its tributaries in Waller County; in central Waller County, including Mound Creek and Irons Creek; and in Brazoria County along Chigger Creek and Cowarts Creek downstream to Clear Creek. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 48 37 51 35 56 / 0 0 0 0 0 Houston (IAH) 70 40 55 39 55 / 0 0 0 0 0 Galveston (GLS) 69 43 54 44 54 / 0 0 0 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...High Rip Current Risk until midnight CST tonight for the following zones: Brazoria Islands...Galveston Island and Bolivar Peninsula...Matagorda Islands. Wind Advisory until 6 AM CST Friday for the following zones: Brazoria Islands...Galveston Island and Bolivar Peninsula...Matagorda Islands. GM...Low Water Advisory from 6 AM to 6 PM CST Friday for the following zones: Galveston Bay...Matagorda Bay. Small Craft Advisory until 6 AM CST Friday for the following zones: Galveston Bay...Matagorda Bay. Gale Warning until 6 AM CST Friday for the following zones: Coastal waters from Freeport to Matagorda Ship Channel TX out 20 NM...Coastal waters from High Island to Freeport TX out 20 NM...Waters from Freeport to Matagorda Ship Channel TX from 20 to 60 NM...Waters from High Island to Freeport TX from 20 to 60 NM. && $$
