Saturday, January 8, 2011

More on Upcoming TX Rain Event

The above total rainfall forecast map (for the period 6am CST today to 6am CST Sunday) from the National Weather Service's HPC continues to place a big bulls-eye deep in the heart of Texas, and we love it!

As I mentioned in yesterday's post, most of the the rain will take place between 6pm this evening and 6am Sunday morning, with very little actually taking place during the day today (except along the Rio Grande late this afternoon - which will be the initiation point of this rain event).

Here are the 6-hourly rainfall forecasts beginning 12 Noon today:

Rainfall forecast for 12Noon-6pm CST Saturday 1-8-11

Rainfall forecast for 6pm-Midnight CST Saturday 1-8-11

Rainfall forecast for Midnight-6am CST Sunday 1-9-11

Some lingering rains will also continue in southcentral and eastern portions of the state from 6am through Noon on Sunday:

Rainfall forecast for 6am-12Noon CST Sunday 1-9-11

A strong upper-level weather disturbance, currently organizing over Arizona and Mexico, will lift East/Northeast today, reaching Texas late this evening (click to enlarge the annotated GFS Computer Model Forecast images below):

The system will continue to lift East/Northeast across the state through midday Sunday, with showers and thunderstorms producing widespread, beneficial rains for much of the southeast half of the state:

Yesterday I mentioned the possibility that a few of the thunderstorms tonight could become strong to severe.  That possibility still exists.  The Storm Prediction Center is not currently forecasting a severe weather "risk area" for the region (see images below) however they do mention the possibility of isolated hail or wind gusts to near severe limits in portions of southcentral and southeast Texas tonight and early Sunday morning.

No Widespread Severe Weather is Currently Forecast

Area with a 5% Chance of Hail Reaching Severe Limits

Area with a 5% Chance of Wind Gusts Reaching Severe Limits

Area with a 2% Chance of a Tornado

There are two main limiting factors at this time, as far as severe weather production is concerned.  That is the fact that the event will take place at night and with cooler air overspreading the region, and for much the same reason, low level moisture and instability will be relatively low (especially compared to what is normally present during a severe weather episode).

None-the-less, residents of southcentral and southeast Texas should remember there is a threat for at least marginally severe weather later tonight and early Sunday, in addition to the much needed rains that will be falling across the region.

By 6pm CST on Sunday, the system will be impacting much of the lower Mississippi Valley, with widespread heavy rain & thunderstorms.  

This system will go on to contribute to a winter weather event that is expected to unfold later Sunday and into Monday (coinciding with the arrival of very cold air for much of the nation early next week).  More on the winter precipitation and cold weather threats in a post later this morning...

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