Monday, October 19, 2015

Rain is on the way!

Forecast Discussion

Upper level trough of low pressure over the western United States is allowing for surface pressure to drop across the front range of the Rockies in Colorado, these features have allowed south southeasterly winds to return to the area. Those southerly winds will work to increase moisture levels across the area. As that trough continues to push southeast, southwesterly winds aloft ahead of the approaching trough will help to pull in Pacific moisture over the state at the mid and upper levels of the atmosphere. At the same time, deep tropical Gulf moisture will be moving into central Texas at the surface. 

Western Trough (notice how the green lines dip to the south across the western U.S. That's the trough, or dip in the jet stream that creates lift (rising air) in our atmosphere (Image courtesy of the University of Arizona's Department of Atmospheric Sciences)


You will really begin to feel that moisture by Wednesday as dew points, or the measures of the amount of moisture in are air, are poised to climb into the 60s and lower 70s across the area. The higher the dew point, the more muggy the air, when you get dew points above 70ยบ that is down right air you can wear. The approaching upper level lift associated with the trough or dip in the jet stream approaching the area from the west combined with a surface frontal boundary and loads of moisture will work together to bring several opportunities for rain across south central Texas. The heaviest of the rains look to arrive Thursday-Saturday. Latest forecast model guidance is indicating the potential for some very heavy rainfall across the area by the end of the week with some areas showing the potential of receiving upwards of 4-7 inches of rain, with many areas receiving over 2 inches. This would be a welcome sight across drought-stricken central Texas, however, there will be the potential for some flash flooding if all of this rain decides to fall on the same day over a short amount of time. That is something we will need to monitor over the coming days. Clouds and rain in the forecast for the middle to end of the week will help to keep highs down in the 70s across the area, however, it will feel quite soupy out there with all of the moisture in the air with overnight lows only dropping into the upper 60s to lower 70s compared to the 40s and 50s we have been enjoying across the area the past few mornings. 

Forecast Rainfall Accumulation
Latest runs of the GFS Model indicating widespread heavy rain across the area 

Image courtesy of Tropical Tidbits

***I will be analyzing the situation closely over the coming days and will update as necessary...as of right now, it appears that all of the necessary ingredients are coming together for a potentially heavy rainfall event across the area...remember, we are dealing with the weather and things are likely to change over the coming days, so please stay aware of the weather situation and know there is the potential for heavy rain across the area later this week***

***In addition to the potential for heavy rainfall and possible flash flooding, storms that develop mid to late week will have the potential to produce deadly cloud to ground lightning. Remember, when thunder roars, GO INDOORS!!***

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