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 112351 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 551 PM CST Thu Feb 11 2021 .AVIATION [00Z TAF Issuance]... Scattered showers and isolated thunderstorms are spread out across the area as a cold front moves through the area. Precipitation activity should slide towards the coast ending the chances at all terminals besides GLS and LBX by midnight, with the precipitation clearing those coastal sites by the morning. Ceilings of 700 to 1000 ft are also seen across the area currently with visibilities ranging from 3 and 6 miles due to either heavy rain or fog. The IFR CIGs will persist through the night with patchy fog, but the area should begin to see some improvement to MVFR conditions by the afternoon. Fowler && .PREV DISCUSSION /Issued 320 PM CST Thu Feb 11 2021/... .SHORT TERM [Tonight through Friday Afternoon]... Winter weather advisory for the northwestern-most counties extended until 10 pm. Cold front has pushed out well south of the coastal waters and winds have come up a few knots moreso with gusts - 15 to 20 mph sustained with wind chills of 29 to 37 were commonplace at 2 pm. Short wave moving through the Hill Country is producing more widespread wintery precipitation over the Hill Country and the eastern edge will impinge on SETX late this afternoon and tonight as the s/w shifts eastward. More widespread liquid rainfall is expected across SETX late this afternoon and tonight spreading east then southeast tonight and tapering off from the northwest. Areas across Madisonville to Caldwell will continue to have patchy freezing light drizzle/freezing rain/sleet/rain into mid evening before it tapers off. The advisory is set to expire at 10 pm but temperatures at 10 pm may hold at 30-33 degrees there which would indicate that any icy roads may not improve even though the precipitation (and Advisory) have ended. Low temperatures overnight will be a slow slide down to 30-37 north of I-10 and 38-42 south of I-10. Friday morning the rain should be confined to mainly the 59 corridor southeastward with scattered/numerous showers and isolated thunderstorms possible well offshore near the 850 front. But inland in the afternoon it should be just chilly with some patchy light rain in the upper 30s/lower 40s. 45 .LONG TERM [Friday Night Through Thursday]... *** OVERVIEW *** * Surge of Arctic air arrives on Saturday with temperatures approaching freezing across most of the area by Sunday night. * First of two disturbances arrives on Saturday, bringing mostly rain with higher chances of mixed precip north of I-10. * Second system arrives late Sunday into early Monday. With colder temperatures in place, widespread wintry precipitation could impact most of the area during this time. * Behind the second system, prolonged stretch of below freezing and potentially historically low temperatures will last well into next week. Another round of precipitation may arrive by mid-week. A highly impactful and potentially historic period of prolonged cold temperatures with multiple episodes of winter precipitation is expected to impact SE Texas over the next week. With persistent deep surface high pressure in place over the central CONUS, arctic air will continue to push into the area as we head into the weekend. By Saturday, high temperatures are unlikely to break out of the mid-40s with lows approaching freezing north of the Houston metro. Our first shot at winter precipitation will arrive on Saturday evening as an upper shortwave trough pushes through the area. Precipitation type will be highly dependent on the timing of this feature, though a period of freezing drizzle/mixed-phase precipitation may occur north of the Houston metro but elsewhere to the south model soundings continue to favor a cold rain. Our main area of focus continues to be the arrival of a second, more amplified shortwave on late Sunday into early Monday. As this feature pushes towards SE TX and develops a slight negative tilt, GFS/EC solutions indicate the formation of an associated coastal low over the western Gulf of Mexico. PWs will remain in the vicinity of 1-1.25 in as this feature continues to develop, and model soundings remain well-saturated. With lows on Sunday evening expected to dip into the 20s to low 30s across the overwhelming majority of the area, an impactful winter precipitation event is anticipated. While precipitation type will remain highly dependent on the timing of this system`s arrival and the exact vertical temperature profiles present across the area (i.e. the presence and extent of an elevated warm layer), we are becoming increasingly confident in a widespread mixed-phase event beginning Sunday night and persisting into Monday. Global deterministic solutions continue to indicate the possibility of snow, sleet, and freezing rain impacting portions of the area during this time. This will make for a particularly hazardous commute on Monday, particularly for those who travel on elevated roadways or bridges. Surface streets may become involved as well given these persistent cold temperatures. Travelers are urged to pay close attention to the latest forecast as this situation develops. Over the next few days, timing, amounts, and types of precipitation will become more refined as higher- resolution guidance becomes evaluable. Upon the exit of the second system and subsequent clearing, SE TX looks to experience its coldest night in many years on Monday evening. Low temperatures across the Brazos Valley and other northern zones remain progged to drop into the single digits, while the Houston metro is expected to reach the low to mid 10s. Along the barrier islands and coast, temperatures will still remain well below freezing. Daily records are likely in play for several days at each of our climate sites. These conditions will be extremely hazardous to the "4 P`s" - people, pets, plants, and pipes. Consider the actions you will need to take to ensure the protection of each of these things. Risk may be further compounded by the possibility of power outages given the expected winter precipitation earlier in the day and increased energy demand for the heating of buildings. Freezing temperatures are expected to last well into the upcoming week, with lows remaining in the 20s for at least parts of the area through next Thursday. Another episode of winter precipitation is possible on Wednesday/early Thursday as a third upper trough pushes through the area, though the timing of this system and temperature profile across the area remains highly uncertain across model solutions. Now is the perfect time to prepare for this period of hazardous weather. Be sure to have multiple ways to receive weather information and continue to monitor the forecast, particularly if you must travel this weekend and early next week. Cady .MARINE... Moderate to strong offshore winds in the wake of the cold front will continue through the weekend. SCA flags for winds near 20 knots with seas of 4-9 feet. High pressure continues to push south Friday and will help to create a swath of concentrated elevated showers and thunderstorms between the 850 and 975mb front in a zone of favorable frontogenesis into early Saturday morning. Potent s/w rotates through Saturday night which should help to lessen the coverage of showers but lingering light rain will remain as moderate to strong isentropic upglide commences Sunday morning with a coastal low taking shape Sunday evening near Brownsville. This low tracks northeast and the arctic airmass plunges southward and into the coastal waters Monday morning. This is likely to the be coldest airmass to move out over the Upper Texas Coastal Waters in more than a decade and in fact perhaps since the 80s. Gale conditions are very likely with sustained winds of 30-35 knots and gusts of 45 to 50 knots. Bitter cold wind chill readings will plague the area Monday and Tuesday. Freezing spray on the bays may even become an issue with air temperatures of 15-23 degrees howling across the bays Monday night. Wind chill readings of 8 to 20 degrees extending well offshore. The gale force winds should begin to relent Tuesday with SCA conditions coming to end by late Tuesday. Next system will bring back moderate southeast/easterly flow Wednesday morning. 45 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 30 37 34 39 31 / 80 20 10 20 30 Houston (IAH) 37 42 38 44 34 / 70 30 20 20 30 Galveston (GLS) 42 44 43 47 39 / 80 50 30 20 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Winter Weather Advisory until 10 PM CST this evening for the following zones: Brazos...Burleson...Madison. GM...Small Craft Advisory until 6 AM CST Friday for the following zones: Galveston Bay...Matagorda Bay. Small Craft Advisory until midnight CST Friday night 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. && $$
No comments:
Post a Comment