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 262335 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 635 PM CDT Fri Mar 26 2021 .AVIATION... Lowering ceilings/visibilities to IFR/LIFR expected tonight/overnight as warm front continues to move further inland. Could see some -DZ too. Improvements expected to begin mid to late morning hours tomorrow as south winds increase across the area. Might get some SHRA development (mainly north around CLL-UTS areas) tomorrow afternoon, but better chances (maybe even some TSRA) are anticipated late tomorrow night and on into Sunday morning as cold front moves into the area. 42 && .PREV DISCUSSION... /ISSUED 340 PM CDT Fri Mar 26 2021/ SHORT TERM (Through Saturday Night)... A weak warm front is moving through the region and dew points are in the 60`s near the coast and around 50 well inland. Moisture will continue to stream into the region tonight and clouds are expected to increase overnight. In addition to the clouds, the saturated layer will deepen to around 850 mb with dry air and slightly stronger winds aloft. This type of pattern favors some spotty drizzle or very light rain. Will maintain the mention of drizzle in the wx grids between 06-15z. The cloud cover and increasing dew points will keep MinT values on the warm side tonight and low temperatures will remain in the 60`s tonight. 850 mb temperatures are near 19 C on Saturday and this would support MaxT values in the mid/upper 80s but increasing winds will lead to more mixing and cloud cover should limit heating so will keep Saturdays MaxT values near todays values. A weak short wave moving across North Texas will bring a chance of showers and isolated thunderstorms to the northern half of the CWA late Saturday and Saturday night. Surface low pressure will develop late Saturday near the Arklatex and move toward the Ohio River Valley Saturday night. A cold front associated with the low will drop into SE TX Saturday night. The front will trigger additional showers and isolated thunderstorms with cooler temperatures filling into the region behind the front. LONG TERM [Sunday Through Friday]... The focus in the extended period continues to be the approach of two surface cold fronts. As a deepening surface low over the Ohio Valley drags a surface cold frontal boundary through the Southern Plains on Saturday night and into SE TX by the early hours of Sunday morning, more widespread showers and storms should develop along and ahead of it. Thunderstorm potential will be relatively limited by a fairly robust inversion visible on forecast soundings, but should capping be able to erode an isolated thunderstorm or two cannot be rules out as the front reaches the coast by early afternoon. Model solutions have trended towards yesterday`s GFS, with the EC now showing the front stalling offshore. While the EC continues to depict the formation of a coastal low driven by the passage of a comparatively more amplified upper shortwave/closed low during this time, the trend in frontal placement has resulted in the bulk of QPF being confined to the coastal waters and as a result have backed off slightly on both PoPs and amounts for Monday. That being said, I still expect the most of the area to receive some amount of measurable rainfall during this period and continue to include around 0.25-0.5" of QPF through Monday afternoon. A brief shift to northwesterly winds will prove favorable for a cooler and drier Sunday night and Monday, with most locations seeing dew points in the 40s, afternoon highs in the lower 70s, and overnight lows in the 50s. However, with a quickly departing broad surface high behind the fropa, a shift to onshore flow looks to come by Tuesday morning and a subsequent surge to total PW values to over 1.5". Our next cold frontal passage looks to occur on Wednesday afternoon, with EC/GFS solutions remaining in fairly good agreement in showing its arrival at the coast by early evening. Another round of showers and storms looks to accompany this feature, with offshore winds and clear conditions developing in its wake by Thursday morning. A slightly lengthier period of offshore flow will usher in a cooler and drier end of the week, with highs on Thursday and Friday in the upper 60s to around 70 and overnight lows dipping into the upper 40s to lower 50s. Cady MARINE... Onshore winds will persist tonight as low pressure develops in the lee of the Rockies. As the low moves east, surface winds will veer to the S-SE and the pressure gradient will relax. Wind speeds should begin to decrease temporarily but seas have been slow to subside. Since seas are still above 5 feet at buoy 91, will maintain a SCEC for the offshore waters. Water temperature is now up to 68 degrees so the threat for sea fog looks conditional at best but there could be some patchy fog overnight as warmer air moves over the slightly cooler waters. The surface low will move toward the Arklatex on Saturday and then off to the east on Sunday. The departing low will drag a cold front across the Gulf waters on Sunday with an increasing north wind in the wake of the front. A Small Craft Advisory will likely be required over portions of the coastal waters Sunday into Sunday night. Winds will veer to the northeast Sunday night as surface high pressure moves into the state. The surface high will move east of the region on Monday with an onshore flow redeveloping late Monday. Onshore winds will persist through Wednesday but another cold front will move into the coastal waters Wednesday night with a strong offshore flow developing in the wake of the mid week front. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 64 83 58 71 48 / 0 40 40 30 20 Houston (IAH) 66 83 64 74 54 / 0 20 50 40 20 Galveston (GLS) 67 76 67 74 60 / 10 10 40 50 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...High Rip Current Risk until 7 PM CDT this evening for the following zones: Brazoria Islands...Galveston Island and Bolivar Peninsula...Matagorda Islands. GM...NONE. && $$
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