Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
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196 FXUS64 KHGX 011155 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 655 AM CDT Wed May 1 2024 ...New AVIATION... .SHORT TERM... (Today through Thursday Night) Issued at 243 AM CDT Wed May 1 2024 Active weather pattern returns today and Thursday with periods of showers and thunderstorms, especially during the overnight hours through Thursday. In the near term, stratus and patchy fog will continue to develop across portions of SE TX early this morning. Fog is not expected to be as widespread as yesterday, and is expected to burn early this morning. Low clouds/stratus, on the other hand, will continue through the day, with just some improvement in the afternoon. Increasing warm air advection, and daytime heating will help to spark isolated to scattered showers and thunderstorms late this morning into the afternoon hours. The primary concerns in the short term portion of the forecast revolve around excessive rainfall and convection risks this evening into Thursday. Model guidance continues to support scattered to numerous thunderstorms developing across north central Texas and into Southeast TX later today as a strong upper-level trough moves through on the nose of a strengthening LLJ. West to southwest flow aloft, strong forcing and instability and 0-6 km bulk shear around 25-40 knots will support strong updrafts with these storms. There is a moderate to high probability that this activity will initiate with a supercellular development to our west, eventually evolving into a linear MCS as storms move over our forecast area. Damaging winds will be the primary threat with any strong to severe thunderstorms. This system is progged to be progressive; but latest trends continue to show excessive rainfall over areas where recently had significant rainfall/flooding. For this reason, WPC placed us under a Moderate Risk (level 3 of 4) and a Slight Risk (level 2 of 4)of excessive rainfall today/tonight in their Day 1 Outlook and in a Slight Risk in their Day 2 (Thursday). Most of this activity is progged to be north of I-10. Widespread rainfall totals of 2 to 4 inches can be expected north of I-10, with isolated higher amounts of 5 to 8 inches possible. Up to an inch of rain will be possible for areas south of I-10 (lower amounts towards the coast). The greatest threat of heavy rainfall and strong to severe storms should gradually diminish on Thursday during the day. A Flood Watch has been issued generally for counties north of the Houston metro area from late this evening through Thursday evening. Those living in areas prone to flooding should be prepared to take action should flooding develop. JM && .LONG TERM... (Friday through Tuesday) Issued at 243 AM CDT Wed May 1 2024 Several mid to upper level disturbances embedded in the quasi zonal flow aloft will continue to move over the region through early this weekend. During the early morning hours on Friday, another pulse of low level moisture will move in from the Gulf waters maintaining PWs between 1.5 to 1.8 inches, in particular over the Piney Woods region. In addition, there`s the indication of mid level vort maxes moving over the northern half of Southeast Texas on Friday. Another thing to note is that although the low level jet is at its strongest on Thursday, it may still be present on Friday. Based on this set up, confidence of seeing a few more rounds of showers and thunderstorms on Friday is increasing. For now, the best chances for showers and storms would be Friday morning into early afternoon. Models show very dry air along the mid levels moving into the region in the afternoon and could help suppress some of the rainfall, however, good instability and low level moisture remains throughout the day and could combine with the vort maxes to help maintain isolated to scattered storms over portions of Southeast Texas through late afternoon or early evening. A lull in activity can be expected Friday night and Saturday morning, although we will need to keep an eye on a few more vort maxes that are to pass through Saturday morning. On Saturday afternoon, another round of storms look to develop mainly over the Brazos Valley and Piney Woods region, where moisture and instability remains highest. There will be some capping in place, thus, hopefully PoPs may not be as high as they are currently forecasted (~30-50%). One important thing to note is that the higher PoPs are once again located along and east of I-45 and north of I-10. With the expected rainfall to occur today and Thursday (in particularly over the Brazos Valley and Piney Woods region) along with the potential for localized flash flooding and river flooding, the additional rainfall on Friday and Saturday could aggravate the situation even more. Remember, rivers can see water levels increasing several hours to days after the main rainfall event. Please continue to monitor the latest forecast and have multiple ways to receive warnings. By early next week, fairly tranquil conditions can be expected as mid to upper level riding dominates the local weather pattern. This will result in dry but warmer conditions with highs reaching the upper 80s to low 90s early next week (some locations may reach the mid 90s). PWs will range between 1.4 to 1.8 inches and with dewpoints mainly in the low 70s, conditions will feel even warmer as well as muggy. 24 && .AVIATION... (12Z TAF Issuance) Issued at 648 AM CDT Wed May 1 2024 MVFR to occasional IFR conditions due to low clouds/stratus will continue to develop and surge northward during the day. Isolated to scattered showers and storms will be possible with the best chances overnight. Gusty erratic winds and reduced visibility can be expected with any strong storm. Southeasterly winds will strength this afternoon around 10 to 15 knots. JM && .MARINE... Issued at 243 AM CDT Wed May 1 2024 Moderate onshore winds are expected through much of the forecast period. Winds may flirt with Advisory levels on Thursday. Seas will generally range between 4 to 6 feet over the offshore waters and 2 to 5 feet over the nearshore waters. Also, strong rip currents could occur across the Gulf facing beaches over the next few days. Periods of showers and storms can be expected through the end of the work week. 24 && .HYDROLOGY... Issued at 243 AM CDT Wed May 1 2024 River flooding continues, particularly along portions of the Trinity and San Jacinto rivers. The following river points continue to remain at or above flood stage as of this morning: - Trinity River (Goodrich): Major Flood Stage - Trinity River (Liberty): Moderate Flood Stage, rising to Major Flood Stage today - Trinity River (Riverside): Moderate Flood Stage - Trinity River (Romayor): Action Stage, rising to Minor Flood Stage today - Trinity River (Moss Bluff): Minor Flood Stage - Menard Creek (Rye): Moderate Flood Stage - San Jacinto (New Caney): Major Flood Stage Additional rainfall over the next few days, both over the area and upstream, may result in further water level rises and prolonged river flooding. Remember to heed any instructions from your local officials and to never travel through flooded areas or roadways. Please monitor updated forecasts via the NWS AHPS website and/or the new NWS NWPS webpage (https://water.noaa.gov/) as the river flood threat continues. 24 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 85 70 83 72 / 40 70 60 30 Houston (IAH) 84 72 84 72 / 30 40 40 30 Galveston (GLS) 80 73 80 73 / 30 20 20 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Flood Watch from this evening through Thursday evening for with gusts TXZ163-164-176>179-195>200-300. GM...None. && $$ SHORT TERM...JM LONG TERM....24 AVIATION...JM MARINE...24