Northwest Houston, TX, during the early morning.
West Houston, TX, during the early afternoon.
Northwest Houston, TX, during the early evening.
Summary: The day was warm, wet, and mostly cloudy. Light to really heavy rain drops fell in and around the Houston, TX area during mainly the morning and early afternoon. Isolated light to really heavy rain drops where still falling in some spots in and around the Houston, TX area, during the mid and late afternoon, evening, and maybe night. The sky stayed mostly cloudy. The wind speeds were calm with moderate to moderately strong gusts. I stopped seeing rain sometime during the late morning, or maybe early afternoon/ There was a flash flood watch issued for the Houston, TX area. I didn't see, or hear about any other watchs, warnings, advisories, alerts, or weather statements being issued for the Houston, TX area. The showers and thunderstorms brought flooding to Brazoria County and some isolated spots in and around the Houston, TX area. I didn't see, or hear about any storm damages. The lows were in the 60's and the highs were in the 70's with maybe some 80's.
Locations: Northwest and west Houston, TX.
Thoughts: I was surprised to see the flooding in Brazoria County. I didn't know it rained that much down there.
Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
Versions: 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 3839 40 41 42 43 44 45 46 47
000 FXUS64 KHGX 190217 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 917 PM CDT Tue Apr 18 2017 .DISCUSSION... Overall forecast from previous update is on track but looks like based off model trends showers could develop in the morning with a few storms mainly after 10Z. For now updated the forecast to keep 20 PoPs for the overnight and then ramping up to 30/40 PoPs for tomorrow. Temperature trends look on track for low temperatures in the mid/upper 60s. Given rainfall the last day or two, we may need to monitor for patchy fog for areas that have clearing skies. Overpeck && .PREV DISCUSSION... /ISSUED 709 PM CDT Tue Apr 18 2017/ DISCUSSION...EVENING FORECAST UPDATE Based on radar trends, satellite trends and surface analysis, the overall trend has been for convection to be waning over SE Texas. There is a band of convection between High Island and Port Arthur. Trends have been for this convection to be decreasing. Convection is tied to a moisture gradient with dewpoints in the mid 60s to the west and upper 60s/low 70s to the east. Assuming this boundary becomes more diffuse with time, convection should decrease as result. Overall the thinking is that rain chances should decrease through the night. Water vapor imagery shows a vorticity maximum dropping to the Rio Grande valley. This should help create a shear axis over the area by which any remnants of the MCV will be pushed NE out of the area. This still support some small large scale ascent over SE Texas so will leave some rain chances through the night and tomorrow. Precipitable water values are still around 1.6-1.7 inches which would support locally heavy rainfall. The overall trend in the forecast though supports lower rain chances unless convection ramps up along any outflow boundaries. Main changes to the forecast so far have been to mainly update the forecast for the first 24 hours and we will likely look to update the forecast again around 02-03Z this evening. Overpeck PREV DISCUSSION... /ISSUED 620 PM CDT Tue Apr 18 2017/ AVIATION... Satellite and radar show the results of a bit more stability in the atmosphere after heavy rains last night and this morning, and so have pulled mention of thunder, but still isolated to scattered showers across the area, and expect those to persist into the nighttime hours so the VCSH mentions largely stay. Otherwise, have been a bit more optimistic in ceilings in some spots, and have risen to VFR in the Houston metro, but still come down to MVFR in sites outside the urban core. Some high-res models do spark some seabreeze convection in the afternoon for tomorrow, but given the increasingly unfavorable environment, capped at VCSH from IAH coastward for now. Luchs PREV DISCUSSION... /ISSUED 356 PM CDT Tue Apr 18 2017/ DISCUSSION... After an active 12 hours for the region as a mesoscale convective vortex pushed to near Matagorda Bay from Central Texas, some of the hardest hit areas in terms of rainfall today are receiving some respite. Farther inland (north of Interstate 10), diurnal heating has contributed to isolated to scattered showers but this activity is expected to peter out later this evening with loss of heating. Evolution of the MCV near Matagorda Bay will remain the primary forecast focus for the next 6 to 12 hours as short term guidance continues to struggle with the placement and intensity of the rainfall associated with this feature. Afternoon surface analysis placed the low level circulation associated with this feature near Magnolia Beach. Throughout the day, minimum pressures associated with this low have fluctuated (indicating changes in intensity) with the MCV displaying an overall weakening trend. This has likely been aided by a lack of convection near the center of the MCV (limiting renewed generation of vertical vorticity which is what the MCV needs to maintain its circulation). Additionally, the KHGX VAD wind profiler has shown increasing mid-level winds through the day (10 knots this morning compared to 25 knots this afternoon) and the increased shear associated with this also appears to have helped weaken the MCV. Higher resolution guidance quickly weakens/dissipates the MCV as we head into the overnight hours, however the convective parameterization schemes of these models (RAP/HRRR) often cause them to struggle with the development and/or evolution of these features and until the MCV completely dissipates, confidence in any one of these solutions is low. So what`s the forecast for tonight? Given the environmental trends with the MCV, anticipate it to continue to weaken through the overnight hours but expect to see periods of showers and thunderstorms associated with this feature to move across the coastal waters and possibly move as far inland as the Interstate 10 corridor. One of these bands (which high resolution guidance had been attempting to develop along the Interstate 45 corridor earlier this morning) is currently pushing north-northeast towards Galveston Bay and may move into Galveston, Chambers, and Liberty counties later this afternoon. For the aforementioned reasons, confidence in timing or placement in any one of these bands is low (hence the 50 PoPs or less for tonight) but that does not mean the potential for heavy rain has ended. MCVs are warm core systems and should this feature wobble any farther inland, nocturnal cooling of land would actually result in falling pressures and help increase the pressure gradient surrounding the center of this feature... and this would actually result in enhanced convergence near the center or the MCV (and greater rain chances than currently advertised). Atmospheric moisture content still remains very high (in excess of 1.5 inches) and with forecast soundings maintaining these moisture levels (1.5-1.7 inches) through the overnight hours, at least locally heavy rain will still be possible. As far as surface analysis has shown, there are no remnant outflow boundaries along the coast that would serve as a focusing point for overnight rain (which is what resulted in nearly 8-10 inches of rain falling in Brazoria and Galveston counties this morning), so rainfall expectations overnight are much, much lower than what was observed this morning. Additional 1 to 3 inch amounts cannot be ruled out through tonight with the usual caveats of higher amounts possible should any boundary collisions or training occur. Otherwise, expect lows in the mid 60s to lower 70s tonight. As an upper level disturbance near the Texas Coastal Bend drops farther south towards the Bay of Campeche tomorrow, shower and thunderstorm activity will be more diurnally driven with isolated to scattered coverage from late morning through early evening. Atmospheric moisture will again remain high tomorrow (1.5-1.7 inches) and again, with weak overall flow promoting slow storm motions, locally heavy rain will be possible during the day on Wednesday as well. Expect highs to rise into the mid 70s to lower 80s. Upper ridging builds in from the west on Thursday, limiting shower and thunderstorm coverage mainly to the seabreeze. This ridging is expected to flatten by Friday as a shortwave trough reaches the Southern Plains, with this trough crossing Southeast Texas on Saturday afternoon and night. Medium range guidance continues to decrease QPF along the front (likely as the result of anticipation of the presence of a cap advecting across the region as southwest winds allow 700 MB temperatures to climb near 10 degrees C), but cannot rule out a few showers or thunderstorms as the front reaches Southeast Texas. The trough axis clears the region on Sunday with upper ridging building across the region Monday and Tuesday allowing for dry conditions to resume. The next period of unsettled weather looks to become established by mid to late next week as the next upper trough approaches the region. Huffman MARINE... Mainly south to southeast winds will persist through the remainder of the week. Caution flags are likely and advisories might be needed Saturday night through Sunday morning or Sunday afternoon in the wake of a cold frontal passage. Look for winds to shift to the north beginning Saturday afternoon after the front moves off the coast. The offshore flow behind the front will last until Monday when high pressure moves off to the east and onshore winds return to the area. 42 HYDROLOGY... Rises to action stage are ongoing along the Lavaca and Navidad river basins. Additional rainfall could lead to rises to action and possibly minor along the Lavaca, Navidad, and San Bernard as early as tonight or tomorrow morning and continuing through the end of the week. Additional rises to near action are possible along the Colorado and tributaries of the Brazos River. KLG && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 66 82 67 84 67 / 20 30 10 10 10 Houston (IAH) 67 82 68 84 68 / 30 40 10 20 10 Galveston (GLS) 72 79 72 79 73 / 40 30 10 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ Discussion...39
Hazardous Weather Outlook
Hazardous Weather Outlook National Weather Service Houston/Galveston TX 613 AM CDT Tue Apr 18 2017 TXZ200-210>214-226-227-235>238-191115- Austin-Brazoria-Chambers-Colorado-Fort Bend-Galveston-Harris- Jackson-Liberty-Matagorda-Waller-Wharton- 613 AM CDT Tue Apr 18 2017 This hazardous weather outlook is for portions of Southeast Texas.. .DAY ONE...Today and Tonight Overnight storms are expected to persist and become more widespread the rest of this morning. These storms could produce additional rainfall amounts from 2 to 3 inches with isolated totals from 4 to 6 inches possible through this afternoon. .DAYS TWO THROUGH SEVEN...Wednesday through Monday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activations may be needed. $$
No comments:
Post a Comment