Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
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344 FXUS64 KHGX 290535 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 1235 AM CDT Mon Apr 29 2024 ...New AVIATION... .UPDATE... Issued at 918 PM CDT Sun Apr 28 2024 The Tornado Watch was extended until 11pm for parts of the area. Though isolated severe cells are occurring, and will probably continue for a while, this appears to be transitioning to a flooding event. Scattered cells have evolved into more of a east- west oriented linear line...perpendicular to the 30-35kt llvl inflow from the Gulf. IR imagery depicts a classic "<" from the Brazos Valley across the northern 1/3 of our counties. This implies a favorable environment for training heavy rain. Widesrpead2-5" has fallen across northern parts, with a TRA gage at Caney Creek @ Fryday measuring 8.24" as of this writing (and still raining). We`ve seen 5 minute rainfalls of about 1/2". Expect some very serious flooding to occur over parts of the area...exceptionally dangerous because it is at night. This system isn`t in a hurry to go anywhere. Cold pool should eventually nudge it south overnight into the metro area and eventually off the coast. Have pulled the Flash Flood Watch south into Montgomery and Liberty Counties. Have held off, for now, adding locations further south. Reason being the low level jet and higher PW axis should be trending eastward after midnight. Will be closely monitoring things overnight, and cannot rule out a further southward flood watch expansion into the metro area. Regardless, Houston metro and coastal areas should still anticipate some localized heavy rain and the associated impacts (local street flooding, rises on some creeks/streams/bayous). A very strong reminder...don`t drive into water covered roadways! 47 && .SHORT TERM... (This evening through Monday Night) Issued at 405 PM CDT Sun Apr 28 2024 ...FLOOD WATCH IN EFFECT THROUGH MONDAY MORNING... Light showers are currently ongoing across portions of SE Texas this afternoon, with stronger/severe storms ongoing over portions of Northeast Texas. SPC`s mesocale analysis depicts ample instability across SE Texas, with SFC CAPE values of 2500-4000 J/KG, 3km ML CAPE of 5-150 J/KG. MU LIs of -6 to -8, LCL heights of 500-1000m, and midlevel lapse rates of 6.5-7.5 DegC/km. Ample shear remains present throughout the region as well, with Effective Bulk shear around 40- 50 knots and 3km SRH of 150-250 m2s2. 3km EHI values range from 3-5, Supercell Composite values of 8-12, Sig Tor Parameter values of 1-2, and Large Hail Parameter values of 8-16. Enhanced Stretching Potential values of 1-2 are currently focused west of I-45 just north of the US-59 corridor right now, coinciding with higher VTP values of 2-4. Model consensus and current observations suggest isolated/scattered shower/thunderstorm development across SE Texas this afternoon, with a larger line/cluster of storms forming this evening over portions of the Brazos Valley/Piney Woods along a frontal boundary. This complex of thunderstorms should move east/southeasterly overnight, pushing offshore Monday morning. A Tornado Watch is in effect for areas north of the US-59 corridor until 9 PM Tonight. These discrete storms will be capable of producing all severe hazards, including damaging winds, large hail, and even a few tornadoes. Additionally, these storms will also be capable of producing locally heavy rainfall, with some models suggesting the potential for training storms. A Flood Watch is currently in effect across the northern third of our CWA until 10 AM Monday. Rainfall totals will largely be up to 2" though isolated higher amounts of 3-5" or higher will be possible. Locations outside of the current watch areas will still be under a Marginal to Slight Risk of Severe Weather/Excessive rainfall tonight into Monday morning. Keep an eye on the forecast for additional updates, and be sure to have multiple ways of receiving warnings tonight. The severe weather & heavy rainfall threat come to an end on Monday as this complex of thunderstorms pushes offshore. Isolated showers & storms will be possible Monday night/early Tuesday due to lingering moisture. Otherwise, expect much more benign weather with highs in the 80s and lows in the 60s to lower 70s. 03 && .LONG TERM... (Tuesday through next Saturday) Issued at 405 PM CDT Sun Apr 28 2024 With an active west to southwest flow aloft, a series of disturbances will be moving across the area through much of this period. With precipitable water values remaining on the elevated side, a persistent onshore flow, and a stalling cold front, look for periods of showers and thunderstorms across the area for much of the week, generally higher inland (up north) and lower closer to the coast. Each day, expect high temperatures in the 80s and low temperatures in an upper 60s to lower 70s range. 42 && .AVIATION... (06Z TAF Issuance) Issued at 1229 AM CDT Mon Apr 29 2024 Line of training heavy rain/storms from CLL-UTS and eastward will be sagging southward into the metro and coastal areas as we head into the next 4-6 hours. Reduced visibilities, very heavy rain and gusty winds will be associated with these storms. Bulk of activity will be transitioning off the coast 5-7am. Gradual improvement in cigs will occur as we head into mid morning...eventually becoming VFR from north-south during the late morning and early afternoon hours. 47 && .MARINE... Issued at 405 PM CDT Sun Apr 28 2024 Moderate to strong onshore winds (still at around 20 knots this afternoon) and hazardous seas (10 feet at Buoy 42019 at 2 PM CDT) will continue through late tonight. Minor coastal flooding is expected in vulnerable locations at times of high tide (mainly during the day today). There is a chance of showers and thunderstorms, with the best chances from this evening through Monday morning, and then again during the day on Tuesday (look for higher winds/seas/bays in and near any storms). Winds will gradually decrease late tonight into Monday, with lingering high seas keeping conditions hazardous through much of the day on Monday. Generally moderate onshore flow will persist through the rest of the upcoming week. 42 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 68 84 71 84 / 10 30 10 30 Houston (IAH) 71 84 71 84 / 20 50 10 30 Galveston (GLS) 72 79 72 79 / 20 50 10 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Flood Watch until 10 AM CDT this morning for TXZ163-164-176>179- 195-196-198>200. Beach Hazards Statement until 10 AM CDT this morning for TXZ436>439. GM...Small Craft Advisory until 10 AM CDT this morning for GMZ330-335- 350-355-370-375. && $$