- Global Moderator
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- Joined: Wed Feb 03, 2010 9:24 pm
- Location: Humble, Texas
Potential for a stormy Thanksgiving Day
Cool front has progressed into the Gulf waters overnight and refreshing air mass will be short lived as winds quickly turn back SE and S by Tuesday. An upper level trough will be digging into the western US over the next few days with the northern portion of this trough being progressive and moving toward the Great Lakes which in turn will drag a cold front into TX Wednesday into Thursday. The southern portion of this trough looks to cut-off over the Baja region and remain in that area into the weekend (more on that later).
Moisture and warmth will quickly return to TX starting on Tuesday with moisture levels continuing to build into Wednesday and Thursday. Progged soundings show impressive moisture is forecast to be in place by Thursday with PWS of 1.7-1.9 inches over the region which is near maximum values for mid to late November. As the upper level flow transitions to SW aloft a series of upper level disturbances will move across the region starting on Wednesday and into Thursday. Surface cold front will move into the area on Thursday…although timing differences remain in global guidance and when exactly the front moves across the area. All this points to a period of active weather centered around Thanksgiving day with the passage of the frontal boundary in a deep moisture environment. Currently looking at instability somewhat lacking for any severe weather, but some strong storms could be possible. Rainfall amounts of 1-2 inches look likely over much of the area on Thanksgiving Day with possibly some isolated higher totals given the moisture forecast to be in place.
Front appears progressive and should be to the coast and offshore Thanksgiving evening into early Friday with rain ending from NW to SE. However, the southern portion of the trough remains back over Baja and with SW flow aloft over top of the incoming cold air mass from the north, clouds will likely be hard to clear into Friday. A cold air mass will sink into the state with highs likely only near 60 on Friday. Next question is when does the cut-off system near Baja this weekend begin to head ENE and toward TX. Current thinking is this may happen over the weekend into the early part of next week with increasing chances for showers. Such systems are hard to time and usually eject slower than guidance suggests, but they can also send disturbances out ahead of the main portion and this may happen over the weekend, so while the forecast post front on Thursday is a fairly dry one, there is uncertainly and rain chances may be needed in the post frontal air mass over the weekend.
Member: National Weather Association