Houston, TX radar, during the early morning.
Northwest Houston, TX, during the mid-morning.
The Galleria area of Houston, TX, during the early night.
Thoughts: Still needing some more sleep. It didn't rain although it looked like it was going to with all of the rain that I saw on the radar, during the early morning.
Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
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000 FXUS64 KHGX 160311 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 911 PM CST Fri Dec 15 2017 .UPDATE... Not much was changed from the previous forecast, just tweaked forecast low temperatures to be better in line with the current trends in cloud cover. We`re still expecting a surface low pressure system to move up the coast tomorrow, potentially bringing some severe weather to the coastal counties. This still depends on where the center of the low tracks, but if the coastal counties get into the warm sector there is more than enough low level shear to get some low topped supercells in play. The time window we`re most concerned about this occurring is between around 5 PM and midnight. Some models still have the low tracking just offshore, but it is worth noting that some of the higher-res models (mainly the TX Tech WRF) have been consistently bringing it onshore. Personally, I`m more inclined to lean towards the onshore solution, but we`ll have more confidence as the event gets closer and more hi-res guidance becomes available. Even if the low stays offshore and there is little to no severe threat, all of SE Texas will have the potential for pockets of heavy rainfall with this system. Nuisance street flooding will be possible, but the system should be moving fast enough to preclude any widespread flash flooding. 11 && .PREV DISCUSSION... /ISSUED 545 PM CST Fri Dec 15 2017/ AVIATION [00Z TAF Issuance]... Quite simply looking at high and mid level clouds through the next 12 hours with light/calm winds. The extended portion of the TAF gets challenging as upper level trough approaches from the west tomorrow. Showers may develop after 18Z Saturday with lowering ceilings through the afternoon. The 21Z Saturday through 06Z Sunday time frame will be the most challenging and may see thunderstorms develop for IAH southward in that time frame. Ceilings will likely lower to MVFR in that time frame as convection moves through the area. TAF ends at 00Z Sunday for all TAFs except IAH for the 30 hour TAF which includes this timing of convection and ceilings. The 06Z TAF update will include similar timing for the rest of the TAFs. Timing will likely be adjusted with 00Z model runs and future TAF updates. Overpeck PREV DISCUSSION /Issued 338 PM CST Fri Dec 15 2017/... NEAR TERM [Through Tonight]... Radar shows most showers have pushed offshore this afternoon, though there may be some light showers or drizzle around Matagorda Bay. However, there`s a good chance that none of these returns are even reaching the ground. Satellite imagery shows overcast skies are beginning to break from north to south, though perhaps too late to allow for much more significant warming this afternoon. Sky cover will be a fairly important consideration overnight as far as overnight temperatures go. At this time things look open enough for the far north to radiate down to the upper 30s to around 40, while the immediate coastline will be hung up around or just above 50, with the rest of the area in the 40s. Rain chances look to be quite low except for a slight chance of showers offshore growing towards dawn. SHORT TERM [Saturday Through Sunday Night]... Northeast winds early look to veer towards easterly or just south of easterly, aided by the development of a weak surface low off the coast towards Brownsville. Look for that low to quickly scoot up the coast Saturday night, and its precise path may become dreadfully important for the severity of any storms in the late night hours. A low that is able to move onshore and track just inland will allow coastal areas to briefly enter into the warm sector - in a window roughly from 3Z-7Z - which will help surge dewpoints above 66 degrees and create a thermodynamic situation which would allow for storms to become surface-based. This track would also severely back surface winds and create a situation with significant low level shear and a very largely curved hodograph - a perfect situation for transient, low-topped supercells with potential for tornadic waterspouts and even some brief tornadoes very near the coast. The Texas Tech WRF would be a prime example of this scenario. On the other hand, a track that stays offshore, or even scrapes right on the coastline would limit the potential intrusion of warmer, moister air. The LLJ in this scenario would actually more likely result in a surface layer inversion, and any thunderstorms would become elevated and unable to tap into any low level shear. We`d still see storms, and potentially locally heavy rain - indeed, of the models that follow this scenario, some use convergence on the northeast side of the quickly moving low to generate or at least imply something like a QLCS that could have some briefly torrential rain. On the plus side here, the dynamic wind fields involved should keep everything moving quickly. While isolated points of street flooding could occur, it seems unlikely that we`d see anything worse than that as we just won`t have time for rain to pile up. With the low clearing out quickly on Sunday, that day should generally be quiet, though perhaps with some lingering shower potential near the coast. But, winds will also very quickly become onshore Sunday night, and begin to pump warmer, high moisture air back in. Because of this, we could see the development of sea fog overnight, and low temperatures across the area look to stay above 50 degrees. LONG TERM [Monday Through Friday]... As we go into next week, the closed upper low near Mexico`s Pacific coast should start to eject, though there is some difference of opinion as to how much interference/phasing we`ll see with the northern jet as it does so. Beneath that low, a surface low, or at least a trough may develop that will result in upglide from the onshore Gulf flow and result in a new bout of showers. Monday looks pretty solid for some of this rain, while Tuesday is a little more up in the air. The GFS has a pretty solid surge of northwesterly winds Monday night as the upper trough moves quickly by and dries us out very rapidly. The Euro is a bit more deliberate with the upper low, and though perhaps it has a better defined surface low, a post- frontal northwesterly surge doesn`t look as significant, keeping us from drying out until Tuesday night. Though I would tend towards a slower evolution when it comes to these closed/cutoff lows to our west, I did tamp down PoPs somewhat for Tuesday as the GFS` solution is at least plausible. There will be time to adjust up (or, perhaps down) as we gain greater consensus on this evolution. Despite some deviation here, there is strong consensus in a quick return to onshore flow for the back half of the week. Thursday looks to be relatively drier, but there is a slight chance of a shower. However, potential should increase Friday as lee cyclongenesis over the Oklahoma Panhandle should result in the development of a new low and trailing cold front that is on our doorstep by Friday morning. Look for showers to develop near the front and persist for some time in the front`s wake. This will set the stage for an unsettled period leading up to Christmas. And while there`s fairly high confidence in that, and generally good confidence that colder air will push into the area, there is significant uncertainty about how that may translate into wintry precipitation. At this point, there is so much inconsistency both between models and between individual runs of the same model, that it`s impossible to state much beyond that it will be colder, there will be periods of precipitation, and some sort of wintry precip is possible (but by no means certain!). Indeed, just to make things more fun, the GFS doesn`t even bring the 850 front far into our area, if at all, keeping 850 temps well above freezing for all but our northwest. In the words of my esteemed shift partner, this is a "warm and gross rain" scenario. Not so sure I`m convinced about this as reality compared to the Euro, but I put it there to illustrate that in a place where wintry weather hangs on razor thin margins, those margins are totally swamped by range of potential scenarios at this time. Much like in tropical season with potential threats in the extended period, keep calm, make sure you have a plan, and stay tuned. MARINE... Offshore winds will continue to decrease this afternoon and tonight, but veer to the east and increase back to near advisory levels during the day Saturday as surface low pressure lifts up the Texas coast. Scattered to numerous showers and thunderstorms will be possible as this low shifts towards the east Saturday night with a few stronger thunderstorms capable of producing waterspouts Saturday night through early Sunday morning. A brief period of offshore flow behind this front will quickly become onshore by Sunday night with warmer, moist air moving across the cooler shelf waters resulting in periods of sea fog through Tuesday or Wednesday before a cold front moves off the coast. Huffman && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 40 55 45 67 53 / 0 70 90 10 20 Houston (IAH) 43 58 49 69 58 / 0 40 90 20 30 Galveston (GLS) 52 60 57 66 62 / 0 20 90 40 50 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ Discussion...11
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