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Weather Briefing from Jeff:

Near record afternoon temperatures expected today.

Strong heating combined with increasing SW winds will lead to a rapid warm up today. Expect high temperatures to approach the upper 80’s at many locations with record being from 88-90 across the region and would not be surprised to see these levels reached or broken. Only aspect that may hold back the temperature rise is the wet ground.

Warm weather continues again on Tuesday and Wednesday before a cool front moves into the area and stalls. Models have not been in very good agreement on where this front will stall and when, but have come into better agreement overnight that the boundary should at least move into SE TX on Thursday. Increasing moisture and lift over the boundary along with disturbances in the sub-tropical flow support increasing rain chances Thursday and Friday. Hard to pin point timing of rain chances at this point, but Thursday afternoon and evening into Friday is looking like the wettest period.

While ingredients do not appear overly favorable for severe weather late this week, a few strong thunderstorms will be possible Thursday and again on Friday. Should instability become more than currently forecast the chance for a few severe thunderstorms would increase. Moisture levels do not support a significant heavy rainfall threat although at this point with river flooding ongoing…any rainfall could slow recessions or result in additional rises.

I can report a low of 58F and a high of 95F today!

BlueJay wrote:I can report a low of 58F and a high of 95F today!

Holding steady at 87 down by the Bay.

I had a high of 88.

High of 87 in CLL

FYI

"TEXAS/LOUISIANA — AUSTIN - From TxDot - Flooding from excessive rainfall along the Texas-Louisiana state line has resulted in the states of Texas and Louisiana considering closure of Interstate 10 near the state line as early as Tuesday morning. If that becomes necessary, it will significantly impact east-west traffic in that area and beyond the region. Please visit www.DriveTexas.org and follow @TxDOT on Twitter and TxDOT on Facebook for updates."

https://twitter.com/TxDOT/with_replies

https://twitter.com/La_DOTD/with_replies

https://www.fhwa.dot.gov/trafficinfo/

right now drivetexas.org has the following for the I-10 closure, eastbound and westbound; "expected to end on 3/20/2016 5PM" that's some serious detouring for interstate commerce

Rip76 wrote:FYI

"TEXAS/LOUISIANA — AUSTIN - From TxDot - Flooding from excessive rainfall along the Texas-Louisiana state line has resulted in the states of Texas and Louisiana considering closure of Interstate 10 near the state line as early as Tuesday morning. If that becomes necessary, it will significantly impact east-west traffic in that area and beyond the region. Please visit http://www.DriveTexas.org and follow @TxDOT on Twitter and TxDOT on Facebook for updates."

Increasing rain chances begin tomorrow with the zonal flow along with disturbances. Cool front still looks to arrive Friday bringing cooler temps for the weekend. It will feel like Winter is back to me after returning from Orlando, FL with highs in the upper 80s and lots of humidity.

open / closed / open / closed - how confusing, glad we don't need to drive over that way...

https://www.google.com/search?q=I-10&ie ... &tbs=qdr:h

A weak frontal boundary stalled across our Region will begin to generate some showers beneath the capped environment today and tomorrow as a stronger shortwave approaches Friday from the Rockies. Getting a bit concerned about a chance for heavy rainfall across areas that do not need additional rain in Central, SE, East Texas and SW Louisiana Friday afternoon and into Saturday as PW's increase to near 1-7+ suggesting a chance of some heavy showers and a few thunderstorms quickly dropping an inch or two of rain. Any rainfall will only exasperate the ongoing flooding problems along the Sabine River. Except a stronger front to finally push through during the overnight hours of early Saturday finally drying us out and ushering in a couple of days of much colder weather with highs ranging from the low 60's and night time lows in the mid 40's possible. The extended range forecast suggests some additional rainfall may be possible again next as our Spring weather pattern continues. It is also noteworthy that Lake Travis is just below capacity by a few inches for the first time since 2010. That's a remarkable recovery for the Hill Country Lakes in a year considering the Extreme Drought conditions our Region experienced beginning back in 2008.

Wednesday morning email from Jeff Lindner:

Threat for heavy rainfall will return to the region Friday and Friday night.

Weak surface boundary has moved into SE TX overnight and is nearly stalled along I-10 this morning. Humid and foggy conditions reside south of this boundary with drier conditions to the north of the feature. This boundary will lift back northward today with 60+ degree dewpoints spreading across the entire region. Short wave in the sub-tropical jet stream across S TX will pass over the region this afternoon, but moisture looks to shallow to develop any showers or thunderstorms.

Moisture depth increases on Thursday as defined southerly flow becomes established over the region. Another upper level disturbance will cross the area Thursday afternoon and this will likely lead to at least a chance of showers and thunderstorms, but the lack of any defined surface boundary should keep activity scattered in nature.

On Friday into Friday night a strong cold front will move into TX from the central plains while a well defined short wave approaches from the west. Strong lift comes to bear across the region Friday afternoon and evening and with moisture levels rising to 1.5-1.7 inch of PW heavy rainfall will be a concern. A few severe thunderstorms will also be possible during this period. Main concern is the heavy rainfall potential with deep convection working with a very moist air mass. Overall storm system is progressive and should clear the region Saturday morning, but a 12 hour or so window for heavy rainfall does exist Friday afternoon and evening. Will go with widespread rainfall amounts of .5-1.5 inches with isolated higher totals near 3 inches. Normally this amount of rainfall would not be much of a concern, but with saturated grounds and already flooding rivers….any additional rainfall is going to run-off.

River Flooding:

Nearly every lake in SE/E/N TX continues to pass flood inflows through their flood gates and these operations will continue for the next several days.

Sabine River:

All-time record flood is in progress on the Sabine River with significant impacts ongoing. All-time record flood levels have been set at Burkeville, Bon Weir, and Deweyville. The previous record at Deweyville was surpassed by 1 ft and was set in 1884. The river is at crest at Deweyville and will crest later today at Orange. Massive flooding continues along much of the river basin below Toledo Bend with hundreds if not thousands of structures flooded in Jasper, Newton, Orange, and Sabine Counties and the closure of I-10 at the river as water has overflowed onto the freeway mainlanes. Flooding will be slow to recede given the large volume of water being passed down the river.

Trinity River:

Major flooding is in progress at Liberty and will continue for the next several days as upstream releases from Lake Livingston are maintained. At major flood levels several subdivisions surrounding Liberty are cut-off.

Brazos River:

Flood wave is passing Richmond this morning and the river will crest at Rosharon late today or Thursday. Minor flooding is ongoing on the river below Richmond to below Rosharon in Fort Bend and Brazoria Counties.

Additional rainfall late this week may alter current river recessions and lake releases. Although the rainfall is not expected to be anywhere close to the gravity of the event last week.

The models continue to suggest we may have a chance for some heavy rainfall and possibly a gusty thunderstorm or two particularly Friday into the overnight hours of early Saturday. Getting a bit concerned for a potential disturbance riding NE out of the Eastern Pacific as the sub tropical jet becomes noisy overhead during the late work week timeframe.

Unsettled weather across SE TX the next few days. The SPC has a slight risk area across portions of E TX, Central LA, and S MS today. A large marginal risk area exists across S, Central and SE TX along the N Central Gulf Coast to S AL Friday.

Folks in East Texas into Louisiana need to pay particular attention to the severe threat today. Seeing numerous reports of very large hail across the Dallas/Ft Worth Metroplex this morning where golf ball sized hail has been common and some tennis ball sized hail have done significant damage. These supercells are moving East along an 850mb boundary that is slowly sagging S. Daytime heating will likely further destabilize the atmosphere lending to the possibility of additional severe hail producing thunderstorms as they move generally East.

MESOSCALE DISCUSSION 0225
NWS STORM PREDICTION CENTER NORMAN OK
0937 AM CDT THU MAR 17 2016

AREAS AFFECTED...N CNTRL/NERN TX...SERN OK...SWRN AR...NWRN LA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 171437Z - 171600Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...THE RISK FOR HAIL PROBABLY WILL PERSIST WITH INCREASING
THUNDERSTORM DEVELOPMENT THROUGH MID DAY. POTENTIAL COVERAGE OF
SEVERE HAIL REMAINS UNCLEAR...BUT TRENDS WILL CONTINUE TO BE
MONITORED FOR THE POSSIBILITY OF ONE OR MORE WATCHES.

DISCUSSION...THUNDERSTORM DEVELOPMENT NOW ONGOING APPEARS LARGELY
FOCUSED WITHIN A ZONE OF WEAK LOWER/MID-TROPOSPHERIC WARM ADVECTION
WHICH EXTENDS FROM NEAR THE RED RIVER EAST SOUTHEASTWARD INTO THE
LOWER MISSISSIPPI VALLEY. ACTIVITY MAY BE OCCURRING AS MUCH IN
RESPONSE TO LOW-LEVEL MOISTURE UNDER RUNNING APPARENT STRONGER
MID-LEVEL CAPPING TO THE SOUTH OF THE THERMAL GRADIENT EVIDENT IN
700 MB ANALYSES. MID/UPPER FORCING FOR ASCENT REMAINS WEAK...OR AT
LEAST UNCERTAIN...AND THERE IS NOT MUCH OF A SOUTHERLY 850 MB JET.

LITTLE CHANGE APPEARS LIKELY THROUGH EARLY AFTERNOON /17-19Z/.
GUIDANCE IS SUGGESTIVE OF AN INCREASE IN THUNDERSTORM DEVELOPMENT
ROUGHLY ALONG THE 700 MB THERMAL GRADIENT...EAST SOUTHEASTWARD
ACROSS PARTS OF SOUTHERN ARKANSAS/NORTHERN LOUISIANA...INTO PARTS OF
SOUTHERN MISSISSIPPI. AT THE SAME TIME...THUNDERSTORM DEVELOPMENT
IS EXPECTED TO PERSIST NEAR THE RED RIVER...ACROSS PARTS OF NORTHERN
TEXAS INTO SOUTHERN OKLAHOMA.

CONVECTION IS EXPECTED TO REMAIN LARGELY ROOTED ABOVE A SHALLOW
STABLE SURFACE-BASED LAYER TO THE NORTH OF A QUASI-STATIONARY
SURFACE FRONT. BUT...STEEP MID-LEVEL LAPSE RATES ARE CONTRIBUTING
TO MOST UNSTABLE CAPE IN EXCESS OF 1000 J/KG...IN THE PRESENCE OF
STRONG CLOUD-BEARING LAYER SHEAR ASSOCIATED WITH 40-50 KT WESTERLY
500 MB FLOW. THIS ENVIRONMENT PROBABLY WILL REMAIN CONDUCIVE TO THE
OCCASIONAL INTENSIFICATION OF STORMS CAPABLE OF PRODUCING SEVERE
HAIL.

..KERR/HART.. 03/17/2016


ATTN...WFO...JAN...LZK...SHV...TSA...FWD...OUN...

Spring is almost officially here! Happy St. Patrick's day everyone!

1630Z Updated Storm Prediction Center keeps a Marginal and Slight Risk with a Enhanced Risk of Severe Storms across portions of our Region which includes Louisiana. A Hatch Risked of Damaging Hail is indicated across portions of East and SE Texas mainly along and East of a Madisonville to Lake Livingston line.

Sad to see what the hail did at the Fort Worth Zoo this morning.

http://dfw.cbslocal.com/2016/03/17/hail ... worth-zoo/

The SPC has a large slight risk area across S, Central, E, and SE TX for this afternoon and tonight for thunderstorms ahead and along the front that will move across SE TX tonight dropping highs into the mid 60s and lows in the mid 40s through the weekend.

Morning briefing from Jeff:

A slight chance of a severe thunderstorms late this afternoon and evening.

A tale of two air masses over SE TX this morning…the result of a nearly stationary low level boundary…which extends from College Station to BUSH IAH to Lake Charles. North of this boundary dewpoints are in the mid to upper 50’s while south of the feature dewpoints are in the upper 60’s to lower 70’s. A much stronger cold front is currently moving through OK and will surge southward today arriving into SE TX late this afternoon. With surface heating today the air mass over SC and SE TX will become fairly unstable by mid to late afternoon with SBCAPE of 2000-3000 J/kg…locally higher near Matagorda Bay and cooling mid level temperatures as a short wave approaches in the sub0tropical flow aloft. Incoming front will yield strong surface convergence helping to break any remaining mid level capping that may be in place.

Mesoscale models are actually in fairly good agreement on several clusters of strong to severe thunderstorms developing along the southward surging cold front late this afternoon. These models also develop severe thunderstorms on the MX side of the Rio Grande which move ESE into SW TX and generally toward the coastal bend overnight as a defined MCS. With loss of heating this evening thunderstorm activity over SE TX moving southward from the north looks to gradually decrease, but much better defined development supported by short wave lift coming out of SC TX late tonight into early Saturday morning will need to be watched as a couple of the models want to bring a meso low type feature across our SW counties/Matagorda Bay during this period which would support an enhanced severe threat.

Main severe threats will be large hail and a few damaging wind gust.

Will also need to watch the old low level boundary laying across the region early this afternoon as heating increases instability which could in turn result in a few storms developing.

Saturday will be much colder, windy, and cloudy (at least into the early afternoon hours). Temperatures will struggle to get out of the mid 60’s under strong cold air advection. Winds of 15-25mph will be common. Skies clear Saturday night and winds decrease leading to good cooling with lows falling into the low to mid 40’s. May get into the upper 30’s over some of the normally cool locations Monday morning.

Strong return flow with strong south winds sets in on Tuesday ahead of the next trough/cold front combo expected on Thursday of next week with another round over showers and thunderstorms.

Hydro:

Flood waves continue to pass down area rivers with most forecast points having crested on the Sabine, Trinity and Brazos. Widespread and significant flooding continues on the lower Sabine basin with the river having spread across miles of marsh lands. The massive volume of water being brought down the river will keep flooding ongoing for the next 2-3 days in the City of Orange where some structures have been flooded since Tuesday. There is also some indications that due to the historic nature of this flood event that bridge crossings on the river are playing a part in how the flood wave has been dispersed across the low lands along the river. In many cases the flood has exceeded the base flood design of many of the bridges crossing the river resulting in large amounts of debris collecting against the upstream side bridge decks and impeding or in some cases diverting the flow. Many locations on the lower Sabine River have never experienced a flood of this magnitude in modern times.

Flooding will continue on the Trinity River at Liberty into next week as upstream flood waves from N TX are just now reaching Lake Livingston which is having to maintain high release rates.

On the Brazos River minor flooding in southern Fort Bend and Brazoria County will be decreasing as the flood wave moves toward the Gulf of Mexico.

Rainfall amounts today and tonight should average .5 – 1.0 inch across the region with the potential for any heavier isolated totals to be confined south of I-10. Generally this will not cause any additional river rises and current recessions should continue as forecast.
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