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
000 FXUS64 KHGX 090013 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 713 PM CDT Sat May 8 2021 .AVIATION [00Z TAF ISSUANCE]... SFC high pressure situated over the Eastern Gulf of Mexico and SFC low pressure shifting east across OK/KS will keep the local pressure gradient tight, maintaining moderate to strong southerly winds for most of the TAF period. Expect wind speeds to range between 15-22 KTS and gusts between 23-30 KTS. Winds relax to around 10 KTS Sunday night. Cigs will be turning from VFR to MVFR tonight across most of the SE Texas region and may scatter out Sunday late afternoon and evening (sooner for the coastal sites). BKN/OVC cigs look to return Sunday night. In regards to wx, there is a chance for some showers and storms to develop along the NE quadrant of the CWA on Sunday and could at times affect KUTS/KCXO and possibly KIAH. Forecast soundings do continue to hold strong capping for most of the region Sunday, thus, development will likely be limited. However, if storms do get to surpass the cap and develop, hazards may include strong gusty winds and small hail. 24 && .PREV DISCUSSION... /ISSUED 320 PM CDT Sat May 8 2021/ SHORT TERM [Tonight through Sunday Afternoon]... Warm and breezy this afternoon with a 1020 high over the FL Panhandle and 996 mb low over SE CO with a strong cold front diving into the Central Plains. Yes it is snowing in North Dakota at this hour! Sadly though that cold air isn`t quite going to make it here without a lot of modification. Tonight the warm breezes will continue and should hold the temperatures up in the 70s overnight beneath a strong cap. The low over CO will be moving out into the Southern Plains and filling as the upper support pulls away. The cold front drops south and will likely be just across the Red River by sunrise on Mother`s Day. SETX will still be solidly in the WAA pattern and could see some very isolated sprinkles. Through the day on Sunday the cold front sags slowly southward and the hot dry air coming off the Mexican Plateau spreads over SETX capping the area until the mid to late afternoon hours. Again with the LLJ overhead drawing northward the moisture beneath the cap some very light sprinkles or showers will be possible. By around 2-4 pm the possibility that the cap starts eroding over the northeastern counties increases as does the thunderstorm threat. If (may be a very big if) the cap erodes then storms will intensify quickly with fairly steep lapse rates aloft but that southwest and west- southwesterly flow further up in the atmosphere should limit the severe threat to marginal hail or less likely strong wind threat. The more likely scenario is one with spotty fast moving showers. Temperatures over the south should easily reach the 84-87 degree mark but across the far north could top out in the lower 80s if the storms develop. Breezy/gusty conditions again Sunday so if you are planning on an outdoor lunch for Mom...tie down the sun shades. 45 LONG TERM [Sunday Night through Saturday]... Trends in the guidance has been to keep the slow approaching, then stalled cold front just north of our area Sunday night. This will keep the majority of showers and thunderstorms out of our region. However, wobbles and kinks in the stalled boundary cannot be ruled out keeping the chance of precipitation for Huntsville northwards. SPC continues to keep this area in a Slight Risk of severe weather Sunday night as any thunderstorms that do manage to develop will have a possibility to become strong to severe. There remains a chance of scattered showers and thunderstorms on Monday as daytime heating could help trigger in a moisture-rich environment. There is a possibility that the cap cannot be broken, suppressing any thunderstorms development. If this happens, then expect a muggy, overcast day with isolated, short lived showers popping up. SPC does keep most of the area in a Marginal Risk for strong to severe thunderstorms developing on Monday as the region will have healthy shear and moderate lapse rates helping to support thunderstorms - again, this is if storms are able to break through the cap at all. Rain chances do increase Monday night into Tuesday as a shortwave trough moves over Texas invigorating showers and thunderstorms along the still stalled boundary thats draped across Southeast Texas. Yet another system passes by on Wednesday continuing the wet weather for the region. The boundary finally pushes east of the region late Wednesday as high pressure builds over North Texas. This will lead to a drier end of the week as this high pressure slides into the Northern Gulf Coast by Friday night. Southeasterly flow redevelops on Saturday with this high pressure to the east, starting the cycle of increasing moisture into the region. The increased southeasterly flow on Monday will lead to high temperatures climbing into the upper 80s across most of the area. The exception being in northern Houston County where cooler temperatures behind the stalled front keeps highs in the upper 70s to low 80s. If this boundary sags a bit further south, expect those cooler temperatures to follow. Increased precipitation Tuesday and Wednesday will keep temperatures on the cooler side across the area with highs in the mid to upper 70s. The cooler temperatures persist into Thursday thanks to CAA behind the finally departed front with a gradual warm up back into the 80s by Saturday. Low temperatures Sunday night through Tuesday night will be on the mild side (upper 60s to mid 70s) due to not only the southerly flow, but also cloud cover limiting radiational cooling. Lows then dip down into the 60s across the area Wednesday night through Friday night with the cooler, drier air following the frontal passage. Fowler MARINE... Onshore flow of 15 to 20 kts will increase to 20 to 25 kts this evening and continue through Sunday morning. Caution flags are currently in place for all waters through the late afternoon, but will get transitions to Small Craft Advisories this evening through Sunday morning due to the increased winds, and for wave heights climbing to five to seven feet in the coastal waters. Winds and seas will decrease through the day on Sunday, likely transitioning the SCAs back to SCECs. Though onshore flow will persist through midweek. This will lead to increased rip current risk through midweek along Gulf facing beaches. The persistent onshore flow is due to an approaching cold front that stalls inland on Sunday and stays stalled through Tuesday. It finally slowly enters the coastal waters through late Monday into Wednesday increasing the chance of showers and thunderstorms. High pressure builds in on Thursday bringing back light winds and dry weather through the end of the week. Fowler AVIATION [18Z TAF Issuance]... VFR and breezy with S winds 10-18ktG15-28kt this afternoon. Winds relaxing this evening but remaining elevated throughout the night. MVFR deck redeveloping over the west/southwest areas 1500-2500 ft and expanding quickly north. CLL/UTS area may flirt with LLWS conditions after 06z above 1500 ft. 45 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 72 86 72 86 65 / 10 20 20 30 40 Houston (IAH) 73 87 74 89 72 / 0 20 20 20 40 Galveston (GLS) 75 83 76 81 75 / 10 10 10 10 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...High Rip Current Risk through Sunday evening for the following zones: Bolivar Peninsula...Brazoria Islands...Galveston Island...Matagorda Islands. GM...Small Craft Advisory until 10 AM CDT Sunday for the following zones: Coastal waters from Freeport to Matagorda Ship Channel TX out 20 NM...Coastal waters from High Island to Freeport TX out 20 NM...Galveston Bay...Matagorda Bay... 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. && $$ Aviation...24
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