Monday, February 29, 2016

Super Tuesday Cool Front

Good Monday afternoon folks...

...Low-level Gulf of Mexico moisture has returned...
...SLIGHT chance for showers/thunderstorms late Tues. A.M. through early Tues. P.M....
...Breezy north winds possible Tuesday afternoon behind cool front...
...Slightly cooler and drier conditions expected Wednesday in the wake of Tuesday's cool front...

Forecast Discussion
Low-level Gulf moisture began streaming back into central Texas on Saturday on breezy southerly winds and is firmly in place as of Monday afternoon as evidenced by dew points in the lower 60s across the area. The widespread morning low clouds and patchy fog we have been contending with the past couple of mornings are a direct indicator that Gulf moisture has returned.

An upper air disturbance passing to our north and northeast on Tuesday will push a cool front through central and south central Texas during the late morning/early afternoon hours. As the front crosses the area there will be a slight chance for a shower or storm along and east of the I-35 corridor. Rain chances are around 10% for us here in Austin, 20% for areas east and southeast of the I-35 corridor. Keep in mind, there's a 90% chance you won't see rain on Tuesday.

Capping Inversion to Limit/Squash Widespread Rain/Storm Chances
Although the atmosphere will be unstable, a strong capping inversion, or temperature inversion will be present in the mid levels of the atmosphere. This capping inversion, a layer of warm, dry air aloft, will effectively limit, or cap, the rain probabilities across the area. With that being noted, if a storm or two are able to get going east of the I-35 corridor they have the potential to become strong with small hail and gusty winds.
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Forecast Breakdown

Rest of Today: Partly cloudy & warm with highs in the mid to upper 70s

Tonight: Increasing clouds & mild with lows in the 60s

Tuesday: Cloudy, mild start gives way to a partly sunny, warm midday in the 70s ahead of an approaching cool front...slight chance for a shower or storm along and east of I-35, breezy north winds and clearing skies can be expected Tuesday afternoon with temps in the 70s

Tuesday Night: Clear and cool with lows in the 40s

Wednesday: Sunny and beautiful with highs in the lower 70s, east southeast wind returns by afternoon
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Tuesday's Severe Weather Risk Areas (courtesy of the Storm Prediction Center)

Overnight



6 a.m. Tuesday through 6 a.m. Wednesday



Monday, February 22, 2016

Potent Storm System

Forecast Discussion
A potent upper level low pressure system currently moving over New Mexico promises to bring widespread shower and thunderstorm activity to central Texas late tonight into Tuesday morning. Dynamic upper level atmospheric lift provided by the approaching upper level low pressure system and its attendant surface low and attendant cold front will force air to rise over the area and produce showers and storms. Some of the storms that develop tonight/early Tuesday morning will have the potential to become severe with large hail of up to an inch in diameter and gusty thunderstorm wind gusts in excess or equal to 58 mph.

Current Position of Upper Level Storm System (500 mb height map/mid/upper level water vapor imagery)



Image courtesy of the University of Arizona

The Storm Prediction Center out of Norman, Oklahoma has placed a good majority of central Texas, including the Austin Metro Area, under a MARGINAL RISK for severe weather. Areas south and west of Austin, including San Antonio and points west to the Texas-Mexico Border have been placed under a SLIGHT RISK for severe weather (see map/definitions below)

Marginal Risk: "Isolated severe storms possible...limited in duration and/or coverage and/or intensity...winds 40-60 mph possible, hail up to 1" in diameter possible, low tornado risk"

Slight Risk: "Scattered severe storms possible...short-lived and/or not widespread, isolated intense storms possible, one or two tornadoes possible, reports of strong winds/wind damage possible, hail of 1" in diameter as large as 2" in diameter possible"

Forecast Rainfall Accumulation
Latest forecast model guidance indicating that we could receive a widespread 1-2 inches of rain across the area tonight through noon Tuesday. Given our drought conditions, that would be a welcome sight.

Flooding should NOT be a major issue tonight, however, some urban street flooding, especially in typical poor drainage areas may become dangerous overnight as the heaviest of the rainfall is expected to move through.

Weather Set Up
A weak cool front moved through the area yesterday evening and has now stalled out to our south...that boundary will lift back north tonight ahead of the upper level storm system and allow for southerly winds to increase over the area. Returning southerly winds will only help to prime the atmosphere over the area for showers and thunderstorms.

As the potent upper level storm system/disturbance moves across the area from west to east, a line/complex of storms will push east with it. As it looks to me, the heaviest storms/storms with the greatest potential of producing severe weather may stay south of Austin, potentially affecting the San Antonio Metro Area and points south the hardest. You can clearly see that on the latest run of the High Res Radar...check out that nasty bowing line of storms southeast of San Antonio with lots of moderate/heavy rainfall across central Texas.

Forecast Radar 1 a.m. Tuesday Morning (HRRR Model...High Resolution Rapid Refresh Model)

Image courtesy of WeatherBell Models

WINDY/Cooler Tuesday and Wednesday
On the back side of this disturbance a windy cold front will sweep through the area and really kick up the winds for your Tuesday, especially Tuesday afternoon when winds could easily gust above 40 mph across the area. With that being mentioned, the National Weather Service has issued a WIND ADVISORY for all of central and south central Texas 

Significantly cooler and drier air will pour into the area Tuesday afternoon on those strong, gusty winds.

Let's remain weather aware over the next 24-36 hours as this storm system and cold front move through the area.

Please remember to heed all watches/warnings/advisories issued by the National Weather Service. They issue these for your safety and the protection of your property.

Southeastern US/Gulf Coast Potential Tornado Outbreak Tuesday:
As this same storm system travels east during the day on Tuesday, there is the potential for a dangerous/deadly tornado outbreak across the Gulf Coast/Southeastern United States. The Storm Prediction Center has placed areas along the Gulf Coast under a MODERATE RISK for severe weather. The Storm Prediction Center/National Weather Service defines a moderate risk of severe weather like this: "Widespread severe storms likely...long-lived, widespread, and intense. Strong tornadoes, widespread wind damage, and destructive hail of 2 inches in diameter and greater possible"


Friday, February 19, 2016

Rain Chances Return

Moderate Drought has Officially Returned
Given that we have officially slipped back into drought here across central Texas after 40+ days without measurable rainfall, it is nice to see rain chances back in the forecast. Unseasonably warm and dry weather has led to an increase in the fire danger across central Texas as vegetation continues to dry out.

As I posted yesterday, moderate drought has returned to central Texas as evidenced by the latest drought monitor released yesterday (02-18-16). Areas of central Texas that have not been officially placed in the moderate drought category have been highlighted in the abnormally dry category.

Latest Drought Monitor Update released 02-18-16



Rain Chances Late Weekend/Early Next Week
Rain chances will increase late Sunday into Monday of next week as an upper level disturbance riding a dip in the jet stream moves toward the area and pushes a surface cold front through the region. The upper level lift provided by the disturbance and the surface lift provided by the cold front will both work together to potentially develop some much needed rainfall across the area.

As it looks right now, the bulk of the rainfall will come on Monday as the actual cold front moves through the area. The upper level disturbance, or upper level energy/lift will exit the area behind the initial cold frontal passage on Monday. With this mentioned, rain chances, although slim, will remain in the forecast through Tuesday until another reinforcing cold front moves through the region behind the exiting upper level storm system. The second cold front (late Tuesday/Wednesday) will push some much drier air into the area and effectively cut off our chances for rain.

No severe weather is expected across the area on Monday, however, there may be some thunderstorms around. Remember if you hear thunder you are close enough to a storm to be struck by lightning. It does not have to be raining at your location to be struck by lightning.

WHEN THUNDER ROARS, GO INDOORS!

Day by Day Outlook Now through Wednesday

Tonight: 61° | Mostly cloudy and mild with areas of fog possible | Wind: S 5-10 mph

Saturday: 77° | Dreary, mild morning gives way to a partly sunny,warm afternoon | Wind: S 5-10 mph

Sunday: 75° | Cloudy, dreary, mild morning gives way to a mostly cloudy afternoon with a 20% chance of showers; rain chances increase late Sunday evening to 40% | Wind: S 5-15 mph

Monday: 70° | 60% chance for showers and thunderstorms | Wind: S/N 5-15 mph

Tuesday: 72° | cooler start to the day near 50° gives way to a breezy, warm, and partly cloudy afternoon...20% chance of a shower/storm | Wind: SSW 5-15 mph

Wednesday: 63° | Breezy and cooler behind an early morning cold front...20% chance of AM shower/storm with clearing skies by afternoon | Wind: NNW 10-20 mph


GFS Forecast Rainfall Accumulation (valid now through midnight Thursday)
(This is just a forecast model and does reflect exact rainfall accumulation...use this as a tool to envision what rainfall accumulation may look like across Texas by the middle of next week...if this particular model verifies, we may see a widespread 0.25-0.75 inches of rain across the area with pockets of higher totals exceeding 1 inch. Areas north and east of central Texas look to receive the highest rainfall accumulation)


Image above courtesy of Pivotal Weather





Thursday, February 18, 2016

Drought Returns

Forecast Discussion

As of the latest drought monitor update released today, moderate drought has returned to central Texas along with a large area of abnormally dry conditions. It has been over 40 days since we received our last measurable rainfall here in Austin back in early January.

Latest Drought Monitor Update (released 02-18-16)...click images to make larger




Last Week’s Drought Monitor Update (released 02-11-16)




Dry, windy, and well above average warmth across the region has led to an increased risk of wildfires. Thankfully long range models have continued to indicate the potential for some much needed relief heading our way by the end of the weekend into early next week.


Rain Possible late Sunday into Monday
An upper air disturbance and a cold front will work together to lift the moisture over central Texas late Sunday into Monday. The upper level lift provided by the upper air disturbance and the surface lift provided by the cold front will bring us the best chance of rain we have seen in a long time. Latest long range forecast model guidance indicating we could see 0.25 to 0.75 inches of rain across the area. Of course those numbers will be changing over the coming days as models get a better grip on the forecast. Cooler air looks to move into the area behind Monday’s cold front setting us up for a much cooler stretch (60s/40s) of weather next week compared to the 70s and 80s we have been experiencing for quite some time now. We will keep our fingers crossed for some rain.

GFS Forecast Rainfall Accumulation (valid now through noon Tuesday)...remember, this is just a model and reflects how much rain we may see late Sunday into Monday...forecast rainfall accumulation will likely change as we get closer to the actual weather event:





Image above courtesy of Pivotal Weather

Monday, February 15, 2016

Spring-Like Weather Continues...

Forecast Discussion:

Despite the passage of a morning "cold" front, temperatures have managed to climb into the 70s area wide thanks to abundant sunshine and dry air moving in behind this morning's front. Noticeably cooler tonight into your Tuesday morning. Dry air, clear skies, and calm winds will allow for a chilly night tonight with temperatures dropping into the 40s area wide.

High pressure will remain in control and keep a lid on our atmosphere through the end of the week. High pressure at the upper levels of the atmosphere promotes sinking air over the area. We need rising air, or upper level low pressure to get some rain around here. These areas of low pressure have been passing over the area, however, the atmosphere has just been so dry that no storms, let alone rain, is able to develop.

Highs this week are forecast to be well above average for this time of year in the 70s and lower 80s. Keep in mind the average or normal high for this time of year is in the 60s.

Average High: 65°
Average Low: 45° 

Forecast Breakdown: Valid Tonight through Friday Night

Tonight: 47° | Mostly clear & cool | Wind: N/SW calm-5 mph

Tuesday: 81° | Mostly sunny & warm | Wind: SW 5-10 mph

Tuesday Night: 50° | Clear & cool | Wind: calm

Wednesday: 79° | Sunny & warm | Wind: SSE 10 mph

Wednesday Night: 53° | Mostly clear & cool | Wind: SE 5-10 mph

Thursday: 80° | Mostly sunny, warm, breezy| Wind: S 5-15 mph

Thursday Night: 59° | Partly cloudy/mostly cloudy and noticeably milder | Wind: S 10 mph

Friday: 80° | Partly cloudy, warm, breezy | Wind: S 10-15 mph

Friday Night: 60° | Mostly cloudy and mild | Wind: S 10 mph


Extended Outlook:
Long range forecast models are indicating some changes may arrive to shake this stagnant weather pattern up by late weekend into next week in the form of some rain chances and a stronger cold front.

We've got time to watch this, but it is exciting to at least see the possibility of some rain and some cooler weather returning to the area. Enjoy the spring-like weather for now.

6-10 Day Precipitation Outlook (courtesy of the Climate Prediction Center) indicating the potential for slightly above normal rainfall for next week...this forecast is valid for FEB 21-25, 2016

If you are interested in checking this website out for yourself click HERE


Wednesday, February 10, 2016

Near Record Warm Thursday

Good Evening Folks…

We are enjoying another beautiful spring-like February day across central Texas. Temperatures as of 5 p.m. CDT are in the lower to middle 70s area wide. Temperatures will actually go up even more tomorrow (Thursday) afternoon thanks to a south southwesterly wind ahead of a weak cool front. I’m expecting highs to top out near 80°F Thursday afternoon in Austin. Locations south and west of Austin may get warmer than that. Thursday’s record high is 83°F set back in 1976…we will be close!


***A southwesterly component to the wind generally means a warming trend for us in central Texas. Air is forced to down slope, or decrease in elevation, as it travels from the higher elevations of the Sierra Madre Oriental Mountain Range in northern Mexico into central Texas. This down sloping causes the air to compress and effectively warm. A good majority of the warmest/hottest fall/winter/spring days here in central Texas featured a southwesterly wind***


F.Y.I. | the hottest temperature ever recorded in Austin in February is 99°F set back on February 21, 1996

Forecast Break Down

Tonight: 40s | clear and cool | Wind: SSW 5 mph

Thursday: 80 | sunny and warm | Wind: SSW 5-10 mph

Thursday Night: Low 50s | mostly clear and cool; there may be some patchy fog for areas south and east of Austin | Wind: SW/NW 5 mph

Friday: 77 | sunny and SLIGHTLY cooler | Wind: NW/SE 5 mph

Unfortunately, I’m not seeing any really good rainfall chances in the extended outlook other than some patchy drizzle/very light rain possible this Sunday (Valentine’s Day).
Long range models continue to indicate well above normal temperatures for a good majority of the month with perhaps the potential for some colder air to move into the area closer to the end of the month. Winter is not over yet.  

Monday, February 1, 2016

Fast-Moving Front

Forecast Headlines:

...Fast-moving cold front arrives late tonight/early Tuesday morning...

...Today's Texas Hot Spots
...Laredo tied their record high of 93°F this afternoon set back in 1963...
...Del Rio tied their record high of 91°F this afternoon also set back in 1963...

...Camp Mabry topped out at 77°F today|A.B.I.A. topped out at 78°F today...We will be some 10 degrees cooler Tuesday afternoon 

Cities to our southwest along the Texas-Mexico border tend to see the hottest temperatures with our current weather set-up...west-southwesterly winds blowing off of the mountains of northern Mexico is forced to descend rapidly in elevation...as the air descends the eastern slopes of the mountains it is forced to compress and heat up...that's why a west southwesterly wind across the area typically brings a warm up! You can clearly see the warmth along the border indicated by the orange and red shading.
  
...Cold Front's Position as of early Monday Evening along with temperatures and surface analysis...


(background temperature map courtesy of Intellicast)

...NO significant rain expected with the front tonight, however, a sprinkle or very light rain shower cannot be ruled out late tonight for areas east of the I-35 corridor...low clouds and areas of fog will be possible late tonight ahead of the front, but will quickly be swept away as the front moves through the area...

...High Resolution Rapid Refresh Model (HRRR) showing the front east of I-35 midnight with only a few sprinkles along it|Best chance for storms will remain well to our north...

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Windy, Cooler Tuesday

...Sunny, WINDY, and cooler Tuesday with highs in the 60s...there may be a haze in the sky first thing Tuesday morning thanks to some west Texas dust being kicked up by this front...I think the dustiest conditions will be possible overnight immediately behind the front...

...Cool High Res Visible Satellite Loop from this afternoon showing the dust being kicked up in west Texas...

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Significantly Cooler Middle/End of the Week...Freezes Possible Wednesday/Thursday nights

...Secondary surge of colder air arrives late Tuesday dropping highs into the 50s for Wed/Thurs with overnight lows dipping into the 30s area wide Tuesday night, Wednesday night, Thursday night (freezes will be possible in out-lying and especially low-lying areas across central Texas...especially Wed/Thurs nights)...a light freeze is not out of the question for us here in Austin Wednesday night/Thursday morning...
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Fire Weather Watch issued for the Hill Country Tuesday Afternoon

-This watch includes ALL of the Hill Country counties west of Hays, Travis, and Williamson Counties

-Dry air and strong west northwesterly winds will make conditions ripe for quick-moving wildfires if a fire or two is able to get going

-OUTDOOR BURNING HIGHLY DISCOURAGED
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Record High Set Sunday at Camp Mabry

-Yesterday the temperature soared to a record-shattering 86°F at Camp Mabry...beating the previous 105 year old record high of 83°F set back in 1911

-The airport did not set a record yesterday at 80°F...their record high for January 31st is 82°F set back in 1971
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Weekend Rain?

Latest long range forecast model guidance indicating a potentially west Saturday across South Central Texas. Saturday has the potential to be a wet, raw day with highs only managing the 40s/50s...I'll continue to monitor that. Any rain that we can get at this point will be a welcome sight. It has been several weeks now since our last good rain.

Early rainfall estimates indicating we may receive upwards of 0.25 to 0.50 inches of rain...we are going to need to monitor moisture levels closely because the atmosphere will still be quite dry across the area for a significant rain...time will tell.