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 180001 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 601 PM CST Wed Feb 17 2021 .AVIATION [00Z TAF Issuance]... Not much change in the forecast. Ceilings between 400 to 700 feet will continue through the night with a breezy north wind. Scattered light freezing drizzle possible across the northern half of the area impacting generally IAH northward beginning around 6z transitioning to scattered light snow showers by the early morning hours through the late morning. LIFR/IFR CIGs will continue through noon, but some improvement to MVFR CIGs around 1500 feet will be possible in the late afternoon. Fowler && .PREV DISCUSSION /Issued 301 PM CST Wed Feb 17 2021/... .SHORT TERM...(Tonight through Thursday Night) Low pressure over the western Gulf has moved east and colder air will funnel into SE TX in the wake of the low. Colder temperatures will continue to surge back into SE TX tonight and only persistent cloud cover will mitigate a stronger temperature fall. That said, MinT values will likely bottom out in the mid 20`s far NW to around 30 over the south. Residual water on area roadways will likely refreeze creating icy conditions on area highways/roads and drivers should exercise extreme caution if venturing out tonight. Ice that accumulated on trees and powerlines will not melt and this could also create some trouble if branches should fall on structures or take down power lines. Since the heavy icing that occurred this morning has ended but the risk from residual icing remains and additional light winter precip is expected later tonight, feel a Winter Weather Advisory is more applicable than a Winter Storm Warning in regards to discussing the ice hazard and possible winter precip. Most of the precipitation has exited the area but weak upper level troughing remains over the state and a weak disturbance embedded in the W-SW upper flow will bring additional precipitation to the region later tonight into early Thursday. Fcst soundings and thickness values support a mixture of light sleet and snow changing to all light snow on Thursday morning. Moisture levels look meager and fcst soundings show a lot of dry air in the 850-700 mb layer so not expecting much more than a dusting. That said, there is some fairly strong 850-700 mb frontogenetic forcing from Columbus to Houston. Sometimes, the forcing is strong to compensate for a lack of moisture so it`s something that bears watching. MaxT values won`t warm much on Thursday and will struggle to reach freezing at KCLL and probably only warm into the upper 30`s at KIAH and points southward. Could get a peak of sun late Thursday afternoon as subsidence develops in the wake of the morning short wave. Skies will clear Thursday night and temperatures will once again plunge to very cold values with mid teens likely by sunrise generally north of a Brenham to Trinity line. Temperatures will fall into the lower and mid 20`s over the southern half of the region. A Hard Freeze Watch will be in effect for Thu Night into early Friday. SE TX will be looking at another 10-16 hours below freezing and probably 8 to 10 hours below 25 degrees north of the Brenham-Trinity line. Another Wind Chill Advisory or Warning may also be required as Wind Chill values are expected to fall into the single digits north and teens central. 43 .LONG TERM [Friday through next Wednesday]... I`ll start off with the bad news. Hard freeze conditions return on Friday morning as surface high pressure settles into the South Central CONUS and northerlies strengthen, with residents of the northern counties expected to experience temperatures in the teens once again as the sun rises while the Houston metro unlikely to break 30 degrees overnight. As a result, we have issued a Hard Freeze Watch for all non-coastal counties during this time. Residents impacted by the current power outage situation should plan to continue to take protective actions as the subfreezing temperatures continue. Highs on Friday afternoon will reach the mid 30s to mid 40s, a slight increase over the previous day as a relaxing surface pressure gradient moderates CAA. The remainder of the long-term forecast period brings some better news. One more night of subfreezing temperatures will arrive on Friday evening, with lows once again dipping into the upper teens to 20s at most locations as clearing promotes more efficient nocturnal cooling. However, by Saturday, an eastward shift of surface high pressure will bring about a long-awaited return to an onshore flow pattern which will gradually work to increase temperatures and dew points through the weekend. Most locations finally see the 50s on Saturday and subfreezing overnight lows finally cease. More seasonable, but still below average temperatures return on Sunday as continued WAA allows for highs in the upper 50s to low 60s. A developing lee cyclone will push into the Great Lakes region as troughing becomes dominant over the Central CONUS by early Monday, and a surface cold front extending from this feature will approach SE Texas. Fortunately, the passage of this feature looks to be relatively uneventful. The main question continues to be the extend to which scattered showers will accompany the approaching front. Latest GFS & Canadian solutions indicate more ample moisture return and as a result more precipitation as the front pushes through the area by Monday afternoon. The EC remains drier with less precipitation coverage. Have included slight chance PoPs for most locations for the time being, but this will likely need adjusting based on model consensus over the next couple of days. Temperatures cool a bit with the fropa though am not currently carrying any subfreezing overnight lows on Monday. Clearer and gradually warming conditions look to persist through mid week with highs on Wednesday breaking back into the 70s. Cady .MARINE... Strong winds continue over the NW Gulf in response to a very tight pressure gradient surrounding the departing coastal low. Sustained winds have been around 25 knots with gusts near Gale force. Seas have increased to 13 feet near buoy19 and marine conditions will not change much overnight with only a gentle relaxation of the gradient expected. Will maintain an SCA for the Gulf and bays through 10z Friday and will continue the SCA for the Gulf waters through 18z. A 1035 mb surface high will build into the southern plains on Thursday and surge into South Texas Thursday night keep the gradient tight. The surface high will drift over the west Gulf on Friday with offshore winds relaxing. The high will move east toward the Tennessee Valley on Saturday. This will allow for onshore winds to return and persist through Sunday. Another cold front will move across the coastal waters late Sunday night with an offshore developing in the wake of the front. Offshore winds will prevail on Monday as surface high pressure settles over East Texas. 43 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 25 32 16 34 18 / 20 20 10 0 0 Houston (IAH) 31 39 26 42 26 / 20 20 10 0 0 Galveston (GLS) 36 41 34 45 39 / 10 10 10 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Winter Weather Advisory until noon CST Thursday for the following zones: Austin...Brazos...Burleson...Colorado...Grimes...Houston
...Madison...Montgomery...Polk...San
Jacinto...Trinity...Walker...Waller...Washington.
Hard Freeze Watch from late Thursday night through Friday
morning for the following zones:
Austin...Brazos...Burleson...Colorado...Fort
Bend...Grimes...Houston...Inland Harris...Inland
Jackson...Madison...Montgomery...Northern
Liberty...Polk...San
Jacinto...Trinity...Walker...Waller...Washington...Wharton.
GM...Small Craft Advisory until 4 AM CST Thursday for the following
zones: Galveston Bay...Matagorda Bay.
Small Craft Advisory until noon CST Thursday 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.
&&
$$Hard Freeze Watch
URGENT - WEATHER MESSAGE National Weather Service Houston/Galveston TX 301 PM CST Wed Feb 17 2021 TXZ163-164-176>179-195>200-210>213-226-227-235-181700- /O.NEW.KHGX.HZ.A.0002.210219T0600Z-210219T1500Z/ Houston-Trinity-Madison-Walker-San Jacinto-Polk-Burleson-Brazos- Washington-Grimes-Montgomery-Northern Liberty-Colorado-Austin- Waller-Inland Harris-Wharton-Fort Bend-Inland Jackson- Including the cities of Crockett, Trinity, Groveton, Madisonville, Huntsville, Shepherd, Coldspring, Livingston, Corrigan, Caldwell, Somerville, College Station, Bryan, Brenham, Navasota, Conroe, The Woodlands, Liberty, Cleveland, Dayton, Columbus, Eagle Lake, Weimar, Sealy, Bellville, Hempstead, Prairie View, Brookshire, Waller, Houston, El Campo, Wharton, Missouri City, Mission Bend, Sugar Land, Rosenberg, First Colony, Pecan Grove, Edna, and Ganado 301 PM CST Wed Feb 17 2021 ...HARD FREEZE WATCH IN EFFECT FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING... * WHAT...Low temperatures will fall into the mid teens north of a Brenham to Huntsville to Trinity line and into the 20`s elsewhere. Temperatures will fall bellow freezing by 8 PM and could remain below freezing for 12 to 15 hours. * WHERE...Portions of south central and southeast Texas. * WHEN...From late Thursday night through Friday morning. * IMPACTS...Frost and freeze conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing. PRECAUTIONARY/PREPAREDNESS ACTIONS... Take steps now to protect tender plants from the cold. To prevent freezing and possible bursting of outdoor water pipes they should be wrapped, drained, or allowed to drip slowly. Those that have in-ground sprinkler systems should drain them and cover above- ground pipes to protect them from freezing. && $$Thoughts: Another round of freezing rain with some possible snowand sleet fell across the Houston, TX area this morningand maybe early afternoon. I believe that my dad said thathe saw some snow flakes sometime this morning. There wasa new formed thin layer of ice covering my car this morningbut not enough to prevent me to try and go to work.Was sent home from work due to a low grade fever.but am doing ok now. Possibly from the dramatictemperature changes that is all. Last round offrozen precipitation expected to fall tomorrowThursday morning. My house in the Cooperfield areahas had power for most of the day. It went outfor a for more then a few hours during themonrning and afternoon but has stayed on sincesometime during the early or mid-afternoon.I am hoping that the power continues to stay onthrough the night but we will see. We stillhave running and hot water. What a mess!!!!!My heart goes out to everyone in this.
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