000 FXUS64 KHGX 130140 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 840 PM CDT Wed Apr 12 2017 .DISCUSSION... Shower and thunderstorm activity was a bit more widespread and robust today than I thought would happen last night. Several interesting features on visible imagery that showed an outflow boundary over Galveston County pushing west with the tail end of that boundary intersecting a weak residual outflow boundary from yesterday`s convection enhanced by weak sea breeze extending from Central Brazoria county toward Palacios. Convection was enhanced in central Brazoria into central Wharton counties with the brief funnel cloud reports as the two boundaries collided. Much calmer now and conditions will remain quiet overnight as drier air begins to filter into the region from the east. SREF ensemble guidance suggests more fog possible overnight and with wet ground and light winds, it seems more than plausible. Will add patchy/areas of fog to the weather grids. Will also tweak sky grids and clean up evening PoP verbiage. Otherwise, the rest of the forecast looks on track through the weekend. 43 && .PREV DISCUSSION... /ISSUED 626 PM CDT Wed Apr 12 2017/ AVIATION... The shower and thunderstorm activity has moved west of all but KLBX at 23Z. Do expect the vicinity showers at KLBX to be west of that area by 00Z. The main issues for this forecast will be the onset of MVFR/IFR or lower conditions later tonight, and then the timing of when the conditions will lift to VFR. Winds may become an issue tomorrow (Thursday) afternoon. Model sounding forecasts show the best potential for MVFR conditions to be between 06Z and 15Z. Best potential for IFR or lower will be generally from 08Z to 14Z. As the low-level temperature inversion breaks toward midday on Thursday, winds should pick up for the afternoon. Most inland sites should experience breezy southeasterly winds after 18Z. This should diminish around sunset. After the previous 12 hours, did a double check to make sure the models were not showing signs of any rain chances for Thursday. On the contrary, drier air looks to be moving into SE Texas which should limit any shower development. 40 PREV DISCUSSION... /ISSUED 340 PM CDT Wed Apr 12 2017/ DISCUSSION... Fairly active with convection across the upper coastal areas this afternoon, with slow moving scattered showers and isolated thunderstorms producing locally heavy rainfall. A small mid-level disturbance combined with a subtle sea/bay breeze to produce a narrow corridor of 1 to 3 inches of rain. Expect most of this activity to diminish by the early evening hours, but there could still be isolated showers around across w/sw portions of SE TX remaining into the eve. Expect a dry day tomorrow as a drier airmass advects in from the east with precipitable water values dropping to below an inch areawide. Another short wave mid/upper trough will move NE from west TX into the southern plains on Thu/Fri. Showers and thunderstorms associated with this feature should remain W/NW of SE TX. On Saturday expect a chance of rain across eastern areas due to an upper level disturbance lifting northward from the Gulf and combining with deeper moisture. Sunday and into early next week, expect a series of weak mid/upper disturbances to move west to east across the area and produce a slight chc/chc of rain. Hard to time any convective events for early next week. No significant chgs are expected to the temps during the forecast period. Mins will be in the 60s and highs in the lower to mid 80s. 33 MARINE... Persistent southeasterly winds 8-14kts with seas of 3 to 5 feet will be the pattern through Tuesday. Ridge of high pressure remains over the SE US and maintains this onshore flow. As a disturbance moves into the state Sunday/Monday expect to see a least a few knot increase to the winds. 45 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 63 82 61 82 62 / 20 10 10 10 10 Houston (IAH) 64 82 63 82 66 / 20 10 10 10 10 Galveston (GLS) 70 78 70 79 71 / 10 10 10 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ Discussion...43
000 FXUS64 KHGX 120205 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 905 PM CDT Tue Apr 11 2017 .DISCUSSION... A meso-low or wake low developed early this evening behind the departing area of convection. Winds were gusting to near 40 mph at times. A Small Craft Advisory was issued earlier to cover the briefly higher winds. Winds are expected to decrease shortly as the meso-low begins to fill. The other dilemma tonight is whether low clouds of fog develops. The SREF is hitting the northern zones rather hard with visibility dropping below a mile generally north of Hwy 105. KCXO and KLFK are both currently less than a mile. Will add areas of dense fog to the wx grids for areas north of a Columbus to Cleveland line for tonight. Min temps look on track. A disturbance should approach SE TX from the east tomorrow and this feature could trigger some scattered showers. 20/30 PoPs seems reasonable for this. 43 && .PREV DISCUSSION... /ISSUED 613 PM CDT Tue Apr 11 2017/ AVIATION... The area of rain was moving over the coastal areas at 23Z and expect the rain to be out of KGLS and KLBX by 01Z. Confidence in the forecast for the rest of the evening through 15Z tomorrow was moderate at best. Satellite trends for the next few hours show that some clearing can be expected or, at least, VFR conditions. However, model output and guidance show the potential for the development of MVFR to IFR conditions between 08Z and 10Z. At least one model was showing the potential for IFR or lower this evening before 08Z. Best chances for IFR or lower will be from 08Z to 15Z. Ceilings should then gradually lift to VFR by 18Z at the earliest. 40 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 61 80 62 82 60 / 20 20 10 10 10 Houston (IAH) 64 81 63 82 63 / 20 20 10 10 10 Galveston (GLS) 69 79 69 79 68 / 50 20 10 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 11 PM CDT this evening for the following zones: Galveston Bay...Matagorda Bay. Small Craft Advisory until 11 PM CDT this evening for the following zones: Coastal waters from Freeport to the Matagorda Ship Channel out 20 NM...Coastal waters from High Island to Freeport out 20 NM...Waters from Freeport to the Matagorda Ship Channel from 20 to 60 NM...Waters from High Island to Freeport from 20 to 60 NM. && $$ Discussion...43
Hazardous Weather Outlook National Weather Service Houston/Galveston TX 633 AM CDT Tue Apr 11 2017 TXZ163-164-176>179-195>200-210>214-226-227-235>238-121145- Austin-Brazoria-Brazos-Burleson-Chambers-Colorado-Fort Bend- Galveston-Grimes-Harris-Houston-Jackson-Liberty-Madison-Matagorda- Montgomery-Polk-San Jacinto-Trinity-Walker-Waller-Washington- Wharton- 633 AM CDT Tue Apr 11 2017 This hazardous weather outlook is for portions of Southeast Texas.. .DAY ONE...Today and Tonight There are high chances for scattered thunderstorm activity today but confidence is very low on the timing and location of any strong to severe storms. Daytime heating within a moist and somewhat unstable environment...with a possible gust front emanating from northwestern thunderstorm activity...may fire mid morning through late afternoon thunderstorm activity. All elements are in play from any strong storm...gusty winds...hail to quarter size...an isolated tornado...with any storm moving less than 20 mph producing 1 to 3 inch per hour rates that could lead to localized flash flooding. The severe weather threat will quickly come to a close around sunset. .DAYS TWO THROUGH SEVEN...Wednesday through Monday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter awareness may be needed later this morning or during the afternoon. $$
000 FXUS64 KHGX 110322 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 1022 PM CDT Mon Apr 10 2017 .UPDATE... A challenging forecast continues to unfold for Southeast Texas this evening with surface analysis showing a nearly stationary cold front draped north and west of the region (roughly along a Dryden- Lampasas- Mount Pleasant line). Regional radar mosaic shows thunderstorms continuing to develop and intensify along this line, possibly aided by upper level lift from a disturbance lifting into West Texas from New Mexico. With these aforementioned features remaining well removed from the region and aircraft soundings out of Houston showing a persistent capping inversion around 700 mb, shower and thunderstorm activity near the region diminished with loss of heating earlier this evening and has remained minimal. Have lowered rain chances and rain totals through the remainder of the evening as a result. Other changes to the forecast include updating temperatures and dew points based on hourly trends with overnight lows in the 60s to near 70 under mostly cloudy skies. Convective evolution for the overnight period and through most of the day Tuesday still contains considerable uncertainty. High resolution guidance has been indicating that the disturbance over West Texas may provide enough lift to allow thunderstorms along the front to grow upscale and generate a strong enough cold pool to allow this complex to propagate away from the front and into Central or Southeast Texas tonight and into tomorrow morning. However, this guidance continues to struggle with placement and timing of this feature... likely owing to the presence of the strong cap in place across Southeast Texas. Were this system to develop, anticipate it to lose much of its intensity during the early morning hours as it approaches the Interstate 10 corridor as a result of the cap in place. The frontal boundary north of the region is not expected to make much southward progress overnight, but maintaining the Flash Flood Watch in place across the northern two tiers of counties given the potential for activity along the stalled frontal boundary to move off of the boundary. Environmental conditions still remain very favorable for a flash flood threat to materialize across these areas (SPC Mesoanalysis showing precipitable water values across the Flash Flood Watch area 1.5-1.7 inches), but the focusing mechanism for thunderstorms capable of heavy rain development is still uncertain at this time with the front still north of the region and any potential thunderstorm complexes having not yet developed. With the disturbance over West Texas reaching East Texas sometime during the day tomorrow (possibly as late as tomorrow afternoon), the stalled frontal boundary should receive enough of a push to move into the region. This would result in another round of shower and thunderstorm development (especially if the front were able to move through late enough in the day to take advantage of any destabilization from diurnal heating) but timing for this potential round remains uncertain at best... sometime Tuesday morning or later, depending on the speed of the disturbance. Huffman && .PREV DISCUSSION... /ISSUED 612 PM CDT Mon Apr 10 2017/ AVIATION... Confidence remains low with regard to convective potential tonight. Will maintain the tempo for thunder at both KCLL and KUTS but confidence wanes quickly for TAF sites south of these airports. Prefer to take a cautious approach and just mention VCSH/VCTS after 09z for the Houston terminals southward. The latest HRRR and RAP want to take the precip west of the region and fcst soundings show the best potential for precip to be early Tuesday morning between 10-16z. AMDAR soundings currently show a very stout cap in place over Houston. Fcst soundings keeps skies generally cloudy with MVFR cigs. Think there will be enough mixing to of dry air above 800 mb to create VFR conds by late aftn. 43 PREV DISCUSSION... /ISSUED 340 PM CDT Mon Apr 10 2017/ DISCUSSION... Obs at 20Z show cold front now from San Angelo to the DFW Metroplex. Convection is forming along the front but not very strong. A strong/severe storm has formed over Milam County in central Texas so we getting some indication that the capping inversion from the elevated mixed layer may be eroding. AMDAR and CRP/DRT/LCH soundings this morning all had a strong cap around 850-700mb. AMDAR soundings do show that capping inversion still in place but weaker north of Houston. Weak ascent from ageostrophic circulation with the cold front may indeed be enough to locally weaken the cap allowing for surface based storms in the warm sector. Aloft water vapor imagery really does not show much in the way of a jet streak for shortwave for lift so overall neutral vorticity advection. There is a shortwave back over Arizona which could impact the area Tuesday morning. Severe Threat Tonight...With at least some heating, cap slowly eroding, dewpoints in the low 70s and the front pushing south, there is a window for severe weather this evening and tonight mainly north of a Wharton/Cleveland line. The main threat will be more closer to Brenham/Livingston northward, but should the line of storms evolve like the HRRR suggests with its many recent runs, a line of storms could push south. With capping stronger to the south, the line of storms would likely decrease in intensity but still pose a threat for hail/wind. Instability at least for the next 4-6 hours with day time heating will support CAPE of 2000-3000 J/kg over much of the threat area. Lapse rates are steep on area soundings so large hail will be a threat. Deep layer shear should be strong enough to support rotating cells like the one in Milam County which will help with hail threat. Look for any supercell to eventually gust out and possibly form into a line or bowing segment. Basic timing for the storms will be mainly from now through midnight. After midnight HRRR keeps most of the convection over central Texas with a line of storms driving south. Heavy rainfall threat...main threat for heavy rainfall and flash flooding exists again over the same area for severe weather. This area is mainly from Brenham to Livingston. Storm motions will be around 20 knots so storms with rain rates of 1-2 inches an hour could produce locally heavy rainfall. If rain rates are higher, flood threat will only increase. There should be plenty of moisture with 1.6-1.8 inches of precipitable water. Of particular interest is the increase winds on KHGX VAD wind profile at 1000-4000FT AGL with now 35 knots at 2000-3000FT. This will certainly help with heavy rainfall threat if this LLJ can be maintained through the night and provide inflow to storms moving along the cold front. Since the environment supports the potential for flash flooding, a flash flood watch has been issued for the northern 1/3 of counties in SE Texas and matches up with the watch for central Texas. Rainfall amounts in the watch area will likely be 2-3 inches but a few HRRR runs shows isolated amounts of 4-6 inches. Given the environment this may be the upper end of rainfall amounts but enough for a flood threat. Tuesday is a challenging forecast since it largely depends on what happens tonight. There is a shortwave trough coming across Texas from Arizona. Seems to reason that there will be another round of storms for the area so will keep some rain chances going for the forecast. But the mesoscale could really mess up the forecast. Overnight convection with a squall line could very well stabilize the boundary layer for much of the day Tuesday and lead to a rain cool but dry day with no rain. For now rather count on the shortwave trough acting as a trigger for more convection assuming there may be enough recovery of moisture/instability from previous convection. Overpeck MARINE... A moderate/strong onshore flow will persist across the marine areas the rest of the this afternoon into this evening. We should see the gradient relax overnight as a cold front approaches from the north. This boundary is expected to stall just north of SE TX, but a large area of storms developing along this system could track south into SE TX. However, not expecting these storms to reach the coastal waters at this time. This front should wash out/move back to the north by Wed. Generally moderate onshore winds will persist the remainder of the week. 41 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 65 76 63 82 64 / 70 60 20 20 10 Houston (IAH) 67 77 64 82 65 / 40 50 20 20 10 Galveston (GLS) 72 76 70 79 70 / 20 30 20 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Flash Flood Watch until 7 AM CDT Tuesday for the following zones: Brazos...Burleson...Grimes...Houston...Madison... Trinity...Walker...Washington. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 1 AM CDT Tuesday for the following zones: Galveston Bay...Matagorda Bay. SMALL CRAFT SHOULD EXERCISE CAUTION until 5 AM CDT Tuesday for the following zones: Coastal waters from Freeport to the Matagorda Ship Channel out 20 NM...Coastal waters from High Island to Freeport out 20 NM. Small Craft Advisory until 5 AM CDT Tuesday for the following zones: Waters from Freeport to the Matagorda Ship Channel from 20 to 60 NM...Waters from High Island to Freeport from 20 to 60 NM. && $$ Discussion...14
Hazardous Weather Outlook National Weather Service Houston/Galveston TX 255 PM CDT Mon Apr 10 2017 TXZ163-164-176>179-195>200-210>214-226-227-235>238-112000- Austin-Brazoria-Brazos-Burleson-Chambers-Colorado-Fort Bend- Galveston-Grimes-Harris-Houston-Jackson-Liberty-Madison-Matagorda- Montgomery-Polk-San Jacinto-Trinity-Walker-Waller-Washington- Wharton- 255 PM CDT Mon Apr 10 2017 This hazardous weather outlook is for portions of Southeast Texas.. .DAY ONE...This Afternoon and Tonight Strong to severe storms will be possible tonight over southeast Texas mainly north of a Columbus...Conroe...Livingston line. The main threats will be large hail and damaging winds. These storms may also produce heavy rainfall which could lead to flash flooding. A flash flood watch has been issued through tomorrow morning for the area. Severe weather and flooding is not expected to push into the Houston and coastal areas, but we will be monitoring for the possibility of a line of storms to push into the area later tonight. This line may weaken as it pushes south. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Hazardous weather is not expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed tonight. $$
TXZ213-237-238-080500- AIR QUALITY ALERT MESSAGE TEXAS COMMISSION ON ENVIRONMENTAL QUALITY RELAYED BY NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 136 PM CDT Thu Apr 6 2017 ...OZONE ACTION DAY FOR FRIDAY... THE TEXAS COMMISSION ON ENVIRONMENTAL QUALITY (TCEQ)...HAS ISSUED AN OZONE ACTION DAY FOR THE HOUSTON...GALVESTON...AND BRAZORIA AREAS FOR FRIDAY APRIL 7TH. ATMOSPHERIC CONDITIONS ARE EXPECTED TO BE FAVORABLE FOR PRODUCING HIGH LEVELS OF OZONE POLLUTION IN THE HOUSTON...GALVESTON AND SURROUNDING AREAS ON FRIDAY. YOU CAN HELP PREVENT OZONE POLLUTION BY SHARING A RIDE...WALKING...RIDING A BICYCLE...TAKING YOUR LUNCH TO WORK...AVOIDING DRIVE THROUGH LANES...CONSERVING ENERGY AND KEEPING YOUR VEHICLE PROPERLY TUNED. FOR MORE INFORMATION ON OZONE: OZONE: THE FACTS (WWW.TCEQ.TEXAS.GOV/AIRQUALITY/MONOPS/OZONEFACTS.HTML) EPA AIR NOW: (WWW.AIRNOW.GOV/INDEX.CFM?ACTION=AIRNOW.LOCAL_CITY&CITYID=236) TAKE CARE OF TEXAS: (WWW.TAKECAREOFTEXAS.ORG/AIR/AIRQUALITY) $$
