Area Forecast Discussion
Issued by NWS Houston/Galveston, TXVersions: 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 38 39 40 41 42 43 44 45 46 47 48 49 50
000 FXUS64 KHGX 120232 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 932 PM CDT Sun Apr 11 2021 .SHORT TERM [Tonight through Monday Night]... Mild night ahead with high clouds and light winds. Warmer and more humid Monday as flow transitions from easterly to southeast with some gustier conditions in the afternoon. Still a very pleasant Spring day on tap Monday. Will be keeping an eye on the next s/w and weak cold front Monday night bringing at least low end rain chances initially. 45 && .AVIATION [00/06Z TAF Issuance]... VFR...swath of cirrus passing through and will continue to increase in coverage tonight as upper troughing works into AZ/NM Monday afternoon. Lower clouds near the stationary front in the Gulf will be slowly shifting west and northwest as the stationary front gets drawn northwest with the falling pressure in the lee of the Southern Rockies Monday morning. Some patchy MVFR ceilings will be possible over PSX/66R areas but for the most part will be looking for VFR ceilings of 3500-5000ft 15z-00z over the southwest expanding north and east. Front should push down close to or even into the CLL area after 09z/Tue (could also be north with outflow getting further southeast) but with sunset 00z/Tue will be looking for lowering ceilings and probably some areas across the south getting below 1500 feet. 45 && .PREV DISCUSSION /Issued 319 PM CDT Sun Apr 11 2021/... .SHORT TERM [Tonight Through Tomorrow/Monday Night]... No major forecast issues for tonight as high pressure remains large and in charge over SE TX. Light east winds are expected to become a bit more variable overnight per this building ridge...then shifting to the the southeast tomorrow morning and strengthening by tomorrow afternoon. Some very patchy fog will be possible over inland locat- ions overnight given the decreased winds/clear skies and slowly in- creasing moisture from the Gulf. Any fog or low clouds that do form should mix out tomorrow morning as winds begin to pick up. These S/ SE winds could be gusty late tomorrow afternoon as a slightly deep- er surge of low-level moisture moves onshore. With the axis of this higher PW tongue is forecast to be over our western CWA, the better (and initial) POPs should be over these locations during the latter part of the afternoon/early evening. Rain chances are progged to be increasingly more favorable tomorrow night (but still low - 20-30%) with the approach of a weak cold front and an associated shortwave. As for temperatures, a mostly cool/dry night tonight with lows from the mid 50s to the lower 60s. Tomorrow could be a warm/humid one as humidity returns under mostly sunny skies. Lows tomorrow night will reflect the increased clouds/moisture/rain chances- i.e. warmer with temperatures ranging from the mid 60s north to near 70 at the coast. 41 .LONG TERM (Tuesday through Sunday)... Weak upper level ridging over the state will flatten as a weak and broad upper level trough over the inter-mountain west approaches. The flow aloft will be zonal with no discernible troughs or ridges through next week. A weak cold front is expected to approach SE TX and stall over the region through Wednesday before inching it`s way into the Gulf. The front will likely serve as a low level focus for showers but the moisture profile looks lackluster and persistent capping is noted in the 850-700 mb layer. Jet dynamics also look weak in the zonal flow so the forecast is going to be strongly dependent on timing the weak perturbations in the upper flow. Both the GFS and the EC show a weak short wave on Tuesday with the EC a bit more amplified with the upper flow and more aggressive with rainfall. Prefer the weaker GFS as the upper flow just does not look supportive for the deeper amplified solution. A weak cold front will meander across SE TX Tuesday through Wednesday and slowly move into the coastal waters Wednesday evening. The front should serve a a focus for isolated to scattered showers but again the upper flow/jet dynamics preclude anything organized or heavy. That said, MaxT values should be able to warm into the lower 80`s on Wednesday and soundings support a convective temperature of only 80 degrees so there should be additional showers in the afternoon courtesy of heating. Thursday looks like the driest day of the week in the wake of the weak cold front over the Gulf. On Friday, a well defined short wave over SE CO will move east and the although the flow over TX will remain zonal, it does appear that the s/wv will induce a weak trough of low pressure to develop at the surface and this feature will set up a pretty well defined zone of convergence that will move across SE TX in the afternoon. Moisture levels increase with PW values reaching 1.75 inches and fcst soundings show a saturated profile with considerably less capping. Rain chances should increase late Friday into Friday night. Another cold front will cross the region late Friday night or Saturday with conditions drying out for Saturday. MaxT values through the week ahead will be near or slightly below climo due to extensive cloud cover and near or slightly warmer than climo overnight due to expected cloud cover. Temperatures will trend a bit cooler for next weekend in the wake of next Friday`s front. 43 .MARINE... The pressure gradient will relax this evening as low pressure over West Texas weakens. A light to moderate onshore flow will prevail through Monday evening as high pressure remains east of the region. A weak coastal trough will develop Monday night while a cold front dips into North Texas. The cold front will likely stall north of the coastal waters through Wednesday and the coastal trough will produce a light to moderate E to SE wind over the Gulf waters. The cold front will finally cross the coastal waters Wednesday night into Thursday with east winds backing to the northeast. A stronger surface high will build into Texas Friday night and reinforce moderate to strong NE winds for next weekend. 43 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 57 85 65 79 64 / 0 0 20 30 50 Houston (IAH) 60 85 69 83 68 / 0 0 20 30 40 Galveston (GLS) 69 81 71 79 70 / 0 10 10 20 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 10 PM CDT this evening for the following zones: Waters from Freeport to Matagorda Ship Channel TX from 20 to 60 NM...Waters from High Island to Freeport TX from 20 to 60 NM. && $$ SHORT TERM/AVIATION...45 MARINE...11
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