Discussion
You know it is trouble when I post images from GOES WEST that show broad, intense storms, right?
In this case, you can clearly see a sequence of three systems. The first just moved through Texas with heavy rainfall and strong thunderstorms. The next disturbance in the "Conga Line" is obviously the largest and most intense, and is poised to move into California over the next 48 hours. The third disturbance, coming in below the Aleutian Islands, may also play a role in the local Houston forecast in about a week or so.
As "Storm Number One" moves away, partial clearing should envelop most of the Lone Star State, with mild temperatures likely to take shape and continue into the weekend. But the trailing cold front left behind form the Tuesday/Wednesday rainmaker will stall and begin to bubble back northward as a warm front. "Storm Number Two" will interact with this boundary, bringing with a strong tropical moisture and forcing component. The same pattern that you have become familiar with returns: dense fog and drizzle, followed by showers and thunderstorms. We could see a burst of heavy rain in the wee hours of Saturday with the passage of the surface warm intrusion, then another set of showers and thunderstorms in the evening and night of January 12.
Colder air across the western half of the continent will slowly press south and east, with its leading edge stalling just below the Gulf Coast on Sunday morning (and likely staying put in that position through the middle of next week). Heavy rainfall and thunderstorms may let up a bit as we start the work week. But as the main core of energy from the Pacific Ocean storm settles over Texas on Tuesday, a new round of heavy precipitation will expand across the region.
As of now, I do not think the computer models have a good "handle" on the track, structure, and intensity of the low approaching the West Coast. You could say the same about the disturbance southwest of Alaska. But one idea which has emerged on the GGEM and ECMWF model ensemble runs (12z January 9) is that both systems will link with (and possibly phase into) a giant Arctic motherlode moving south and east from Hudson Bay later next week. Yes, these equations have been inconsistent this winter and almost always promise more than is delivered in nature. But I believe the basic scenario to be correct: the first storm hits Texas with heavy rainfall Tuesday/Wednesday and brings more cold air south. Then the third low pressure system digs southeastward in the mean 500MB trough, giving Houston, most of the Old South and Midwest another dose of impressive precipitation the following weekend. With colder readings, this could lead to trouble for our friends further north.
And for the Bayou City, more miserable weather.
Useful Links
GOES Project Science
UW-Madison Department of Oceanic and Atmospheric Sciences
NCEP MODEL ANALYSES AND GUIDANCE
The Forecast
Thursday: Partial clearing and mild. Highs 70 Brenham to 74 Needville
Thursday Night: Clear and mild with locally dense fog developing late. Lows 51 Chappell Hill to 55 Rosenberg
Friday: Fog in the morning, then variable cloudiness with a few sprinkles in later afternoon. Mild. Highs 71 Richmond to 75 Brenham
Friday Night: Dense fog and drizzle, with heavier showers and thunderstorms developing towards daybreak. Lows 56 Prairie View to 60 Sugar Land
Saturday: Variable cloudiness, warm and humid with showers and thunderstorms expanding through the metro area in the afternoon. Highs 75 Waller to 79 Missouri City
Extended Outlook
Sunday: Cloudy and colder with periods of rain and thunderstorms. Early A.M. High 70, Sunday night low 42
Monday: Cloudy, breezy and cool with rain and drizzle. High 51, Low 41
Tuesday: Cloudy and cool with periods of rain and thunderstorms. High 50, Low 40
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