Buckle Up! Ups & Downs on the way!

Forecast Discussion:

TGIF Everybody! What a week it has been! Light wintry mix of precipitation across the area with mainly light mist/drizzle falling across the Austin Metro Area as of 5 p.m. CST Friday evening. Thankfully surface temperatures are running just above freezing across a good chunk of the Austin area with the exception of the northern, western, and northwestern suburbs. Warmer air beginning to advect north around 4-5,000 feet above the surface is riding up and over the dense, cold Arctic Air Mass here at the surface. If that warmer air had not pushed in so quickly above us here in Austin, we could have seen some light flurries/snow showers this afternoon, however, the warming temperatures aloft helped to transition all of the precipitation falling into light mist/drizzle, sleet, and light freezing mist/drizzle. The Hill Country needs to keep an eye on this precipitation through the evening and into the overnight hours as travel may become hazardous on mainly elevated roadways north and west of Austin because air temperatures in those locations are still at/below freezing. With that in mind, the National Weather Service has issued a WINTER WEATHER ADVISORY for the counties shaded in purple on the map below.

OFFICIAL STATEMENT FROM THE NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO FORECAST OFFICE:

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
332 PM CST FRI FEB 27 2015

...LIGHT FREEZING RAIN AND DRIZZLE EXPECTED LATE THIS AFTERNOON
THROUGH SATURDAY MORNING ACROSS PORTIONS OF THE AREA...

.LIGHT FREEZING RAIN AND FREEZING DRIZZLE IS DEVELOPING LATE THIS
AFTERNOON ACROSS THE HILL COUNTRY. THE PRECIPITATION WILL EXPAND
IN COVERAGE OVERNIGHT TO INCLUDE THE EDWARDS PLATEAU AND PORTIONS
OF CENTRAL TEXAS. THE MAIN IMPACTS WILL BE ALONG AND NORTH OF A
COMSTOCK TO MEDINA TO HELOTES TO AUSTIN LINE.

While this technically includes the Austin Metro Area, the biggest impacts from this event should be felt to our north and west. Warmer air continues to advect north through the day on Saturday with continued chances for light rain across the area and plenty of cloud cover. Highs on Saturday should manage to climb into the 40s across a good portion of south central Texas, it’s not out of the question for far southern and southeastern portions of the area to make it into the lower 50s Saturday afternoon.

Sunday, Monday, and Tuesday:

Continual warm air advection pushes highs into the 60s I think for a majority of south central Texas during the day on Sunday…the 12Z run of the GFS Model (the weather service’s model of choice) pushes us to 72°F on Sunday, not sure if we will get quite that warm, but you get the idea…milder temps to be expected on Sunday. Light rain chances continue on Sunday at 40% under what should be a mostly cloudy/partly sunny day otherwise. For all of you folks heading out to the Kite Festival, it doesn't look to be the best day for flying kites as winds will be variable and light along with the chance for rain. We stay in this predominantly cloudy, mild, and showery weather pattern into Monday. A cold front looks to sag south into the area early Monday looking to keep highs down into the mid/upper 50s for much of the area. Rain chances continue on Monday at 40%. That front retreats quickly back to the north Monday night into Tuesday morning and allows for much warmer, moist air to move into the region ahead of our next upper level storm system and its associated cold fronts (yes, cold fronts) move into the area. Highs soar into the mid/upper 70s I think area wide on Tuesday with 80s & 90s possible across much of south Texas. Given the more unstable environment on Tuesday, thunderstorms will be possible Tuesday/Tuesday night…I’m leaving the chance for storms at 30% for now as models are not all that impressed with our chances for rain/storms. As of now the threat for severe weather (large hail, damaging winds, and tornadoes appears to be very low).

GFS FORECAST MAX SURFACE TEMPERATURES ON TUESDAY

ARCTIC BLAST BEGINNING TO LOOK LIKELY NEXT WEEK

Now…this is where things really start to get interesting according to the latest runs of both the GFS and ECMWF Forecast Models…both models show a POWERFUL Arctic Front plunging south through the area Wednesday morning with another round of wintry precipitation for some across south central Texas. As models look right now, this promises to be a potent cold blast with Arctic Air originating over portions of northeastern Siberia!! Widespread hard freeze possible across much of the area next Wednesday night with temperatures dropping into the 20s I think for much of the area.

SIBERIAN EXPRESS (name given to these fast-moving, potent Arctic Fronts in which air associated with it originated in Siberia). Image below: looking straight down at the North Pole with 850mb (around 4,600' above sea level) forecast temperatures superimposed on top)...very cool image. Circled area represents the place of origin of next week's potential Arctic Blast.

Siberian Air Mass highlighted with labeled countries (valid as of today):

Forecast Loop of image above (watch the circled mass of Air plunge into the lower 48)

Valid now through the end of next week

FORECAST COLD FRONT POSITION NOON WEDNESDAY...CHECK OUT THE DRAMATIC TEMPERATURE DIFFERENCE ON EACH SIDE OF THE FRONT (GFS FORECAST MODEL)

 ***PLEASE KEEP IN MIND THAT THIS FORECAST IS NOT SET IN STONE AND IS SUBJECT/LIKELY TO CHANGE A BIT OVER THE COMING DAYS***

• Model Imagery/Graphics above are courtesy of WeatherBell Models, College of DuPage Weather Department, and the National Weather Service.
• Cold Blast graphic courtesy of 5 News Online