Storms Return Thursday

FORECAST DISCUSSION:

El Niño has really begun to show its face across south central Texas over the past couple of weeks as two historic rainfall events have already occurred. Still confused on exactly what El Niño is? El Niño was given its name by Peruvian fisherman, because they noticed that fishing conditions deteriorated for some reason around Christmas time…the poor fishing conditions were determined to be caused by WARMER than normal waters across the equatorial Pacific. Warmer ocean water contains less nutrients for fish, less nutrients = bad fishing. El Niño, in Spanish, means the boy, and was given this name to refer to baby Jesus, because of noticeable warming of the water around Christmas-time. El Niños typically bring us WETTER AND COOLER than normal conditions across south central Texas during the fall and winter months, whereas, La Niñas, the opposite of El Niño, tends to bring us WARMER AND DRIER weather during the fall/winter months. Warmer than normal sea surface temperatures across the Pacific, and in this year’s case, much above normal water temperatures, provide more than sufficient fuel for developing Pacific storm systems, which, move from west to east across the northern hemisphere thanks to the prevailing westerly winds, known as the Westerlies. The subtropical jet stream takes on a more important role during El Niño years and pumps moist, tropical air north for Pacific storm systems to feed on. The amazing thing about both El Niño and La Niña is that their effects are felt on a global scale. The devastating fires and drought ongoing across much of Malaysia can be attributed to El Niño among many other odd weather events occurring across the globe.

Latest Global Sea Surface Temperature Anomaly (as of November 2, 2015)...notice the MUCH WARMER THAN AVERAGE sea surface temperatures across the Equatorial Pacific.

CLICK HERE TO WATCH A SHORT, BUT INFORMATIVE VIDEO ON EL NIÑO

STORMY THURSDAY/FRIDAY

Another upper level Pacific storm system is digging south and east over the western United States and will be approaching Texas late Wednesday into Thursday. Upper level divergence out ahead of this approaching upper level storm system creates low pressure at the surface. Falling surface pressure out ahead of the storm system will allow southeasterly winds to return to the area and ultimately allow rich, tropical Gulf of Mexico moisture to flood back into the area. Thursday into early Friday are going to be the days to really watch as that is when a surface cold front and its associated surface low pressure will move across the state of Texas. Upper level lift aloft in the upper levels of the atmosphere, combined with dynamic surface lift along the cold front, and plentiful amounts of moisture will generate a widespread chance for showers and storms Thursday into Friday. The Storm Prediction Center has already placed all of south central Texas in the MARGINAL RISK category for severe weather on Thursday with areas of the northwestern Hill Country and much of north central Texas under a SLIGHT RISK for severe weather. The Storm Prediction Center is highlighting the risk of severe hail across south central Texas, however, strong, gusty winds and isolated tornado cannot be ruled out.

Thursday Severe Weather Risk Areas (Dark green = MARGINAL, Yellow = SLIGHT)

How much rain are we going to see?

Latest forecast model guidance is estimating a widespread 1-3 inches of rain to fall with this next system, however, that will need to be monitored closely over the next several days. Some areas may have the potential to receive upwards of 4 inches. It is really going to depend on how quickly this cold front clears the area on Thursday/Friday. The heaviest rains will occur ahead, along, and immediately behind the front with lighter, more scattered rains lingering on behind the frontal passage into Saturday as cooler air filters into the area. The reason the rain is going to linger behind the main line/cluster of storms is that the upper level low to our west will take its time to cross the area. Until it does so, rain will be possible across the area. Highs likely to drop into the 60s Saturday and Sunday with lows in the 50s.

Weather Prediction Center's Composite Rainfall Accumulation map (valid today through Sunday)...they are forecasting 1-3 inches of rain across south central Texas

Please stay tuned to the latest forecasts over the coming days and please remember to remain weather aware. El Niño years have the potential to bring us a lot of surprises this fall/winter, so it’s always a good idea to be prepared and informed for whatever Mother Nature decides to throw at us.

Remember these phrases from the NATIONAL WEATHER SERVICE:

IF YOU COME ACROSS A FLOODED ROADWAY, TURN AROUND, DON’T DROWN

WHEN THUNDER ROARS, GO INDOORS