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 310216 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 816 PM CST Sat Jan 30 2021 .AVIATION [00Z TAF Issuance]... Still have lingering MVFR ceilings from around ARM-CXO southward to near the coast including the HOU/IAH areas. Pre-frontal trough has moved through and waiting on the cold front. Winds were south and southwest over SETX with the cold front in the AUS-HDO area pushing southeast. In addition quite a bit of dust got picked up by the dry downsloping winds over W TX and will move into SETX overnight. Much of it is elevated but expect that at sunrise will still have dusty skies here (possibly some slant visibility issues). As the front nears the area expect the ST deck in the southeast to fill in then shift east. By 07-11z much of it should be out of the area except perhaps along the coast. Winds being lighter ahead of the boundary may also lead to patchy fog near the coast but not expecting widespread thick fog just more of the patchy stuff. For now will hold off on all but GLS in mentioning it. NW winds in the wake of the front increasing 12-15z and deep strong mixing should make for gusty north- northwest wind day across the region. 45 && .PREV DISCUSSION /Issued 303 PM CST Sat Jan 30 2021/... .SHORT TERM [Tonight through Sunday Night]... The upper-level low that has brought abundant cloud cover and warm conditions was centered over OK/AR region early this afternoon. Per satellite, the pre-frontal boundary was located across our northwest counties as of 2PM, leading to a sharp clearing and strong dry air advection behind it. TDWR-IAH and HOU radars are only indicating a swath of isolated showers as this boundary moves through. With strong dry air prevailing above 850mb and limited instability, expect only isolated rain through late this afternoon/early evening. Warm southerly flow ahead of the cold front has also led to gusty conditions today with gusts from 25 to 35 mph. Coastal areas have reported gusts up to 40 mph. Winds will gradually diminish early this evening as the cold front arrives. Speaking of, the front/wind shift will move across the region mainly after midnight, reaching the coastal waters by daybreak. Strong dry air advection will be in place in the wake of the aforementioned frontal boundary. Surface dewpoints will quickly fall into the 30s and 40s overnight. Dry and cold northwest flow will lead to a relatively quiet and pleasant Sunday. It will be breezy, but not as quite as gusty as today. Highs will generally be from the upper 50s to upper 60s. Winds decrease by early Sunday evening as the pressure gradient relaxes. Light northwest winds, mostly clear skies and a persistent dry/cold airmass will lead to a cold night Sunday night into Monday. Overnight lows will range from the mid 30s to mid 40s. 05 .LONG TERM... (Monday through Saturday) Cooler temperatures and clear skies are expected on Monday as a 1032 mb high settles over the southern plains. The high will shift east on Monday night and be east of the region on Tuesday. A subtle warm up will begin on Tuesday as onshore winds return on the back side of the retreating high. Temperatures begin to warm more on Wednesday as 850 mb temps warm and weak ridging at 500 mb develops over South Texas. MaxT values on Wednesday should warm into the upper 60`s to possibly lower 70`s. Warm air advection should lead to an increase in cloud cover during the afternoon. On Thursday, the upper ridge begins to flatten as a short wave over CA moves east to southern NM. The flow aloft should become SW and the combination of weak WAA and the SW upper flow should lead to a few showers by afternoon. Capping is strong at 850 mb and its also very dry above the inversion layer so only light showers beneath the cap are expected during the afternoon. A surface cold front will enter the state on Friday and there are still some significant timing differences between the faster ECMWF and the slow GFS and Canadian models. Have slowed the front down a bit and tried to average out the differences and will bring the front through Friday evening with a wind shift to the N-NW and a surge of much cooler temperatures for next Saturday. 43 .MARINE... A Small Craft Advisory is in effect for the offshore waters through 12z Sunday as a tight pressure gradient has fostered a strong onshore flow of 20 to 25 knots. Seas exceed 8 feet and even though the gradient will relax later tonight and winds subside, the seas will take some time to dampen out. The SCA has been extended for elevated seas. The strong onshore flow las also created strong rip currents and Rip Current Statement is in effect through 03z. A cold front will cross the coast later tonight with a moderate to occasionally strong offshore flow developing in it`s wake. Another SCA (or an extension) may be required for the Gulf waters on Sunday. Cooler air over the warmer water should keep strong winds and elevated seas going Sunday night. Winds should relax on Monday as high pressure settles over over the southern plains. As the high shifts east, an onshore flow should develop on Tuesday. Onshore winds will then persist into Friday. Wind speeds will increase Wednesday night through Thursday night as low pressure develops over the TX panhandle. The next cold front should across the coastal waters Friday night. 43 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 46 62 38 62 35 / 0 0 0 0 0 Houston (IAH) 51 64 41 62 39 / 10 0 0 0 0 Galveston (GLS) 57 65 46 60 48 / 10 0 0 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...High Rip Current Risk until 9 PM CST this evening for the following zones: Brazoria Islands...Galveston Island and Bolivar Peninsula. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until midnight CST tonight 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. Small Craft Advisory until 6 AM CST Sunday for the following zones: 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. && $$ AVIATION...45
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