July 2014: Stalled Front/ Rain Chnaces To End July

[srainhoutx]

I picked up a very quick .72 inches of rain in about 10 minutes up here. The storms are capable of dropping a lot of heavy rain rather quickly if you happen to be lucky enough to get under one of the stronger cells.

[srainhoutx]

The Weather Prediction Center places a rather large Moderate Risk for Excessive Rainfall across portions of NE/E/SE Texas as well as much of Southern Louisiana.

[srainhoutx]

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
235 PM CDT THU JUL 17 2014

TXZ163-164-176>179-198-172030-
GRIMES TX-TRINITY TX-MADISON TX-SAN JACINTO TX-POLK TX-HOUSTON TX-
WALKER TX-
235 PM CDT THU JUL 17 2014

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL HOUSTON...EASTERN
MADISON...CENTRAL WALKER...NORTHERN GRIMES...NORTHWESTERN POLK...
TRINITY AND NORTHWESTERN SAN JACINTO COUNTIES UNTIL 330 PM CDT...

AT 235 PM CDT...DOPPLER RADAR WAS TRACKING A LINE OF STRONG
THUNDERSTORMS ALONG A LINE EXTENDING FROM NEAR POINT BLANK TO 7 MILES
WEST OF RIVERSIDE TO NEAR BEDIAS...AND MOVING NORTHEAST AT 35 MPH.

WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
APPLE SPRINGS...TRINITY...ONALASKA...CORRIGAN...GROVETON...POINT
BLANK...LOVELADY...RIVERSIDE...BEDIAS...MIDWAY...SEBASTOPOL...
OAKHURST...CENTRALIA AND PENNINGTON.

[Rip76]

Typical cloud cover in the morning.
Atmosphere doesn't heat up, storms weaker.

Tomorrow may be pretty interesting though.

[sambucol]

How much rain/bad weather are we getting tomorrow?

[jasons2k]

That wedge on the WPC maps looks suspiciously like a dry slot.

[srainhoutx]

HGX offers another informative AFD today...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
400 PM CDT THU JUL 17 2014

.DISCUSSION...
SURGE OF GULF MOISTURE HAS PUSHED FAR INLAND TODAY WITH A WARM
FRONT STRETCHING FROM DFW TO TYLER AND THEN IN C LA. DEEP MOISTURE
CHARACTERIZED BY PRECIP WATER VALUES OF 2-2.2 INCHES HAS DEVELOPED
SOUTH OF THE BOUNDARY AND IS WHERE MOST THUNDERSTORM ACTIVITY
CURRENTLY RESIDES NORTH AND EAST OF A COLLEGE STATION TO HOUSTON
LINE. ALOFT WATER VAPOR SHOWS A STRONG SHORT WAVE TROUGH MOVING
INTO THE S PLAINS WITH A NICE DRY SLOT COMING INTO THE TX
PANHANDLE. THIS SYSTEM SHOULD CONTINUE TO PROVIDE STRONG LARGE
SCALE ASCENT OVER MUCH OF TX TONIGHT INTO FRIDAY AS IT SLOWLY
MOVES TOWARDS THE MISS RIVER VALLEY TOMORROW WITH A POS TILT.
TROUGH AXIS SHOULD EXTEND BACK TOWARDS SE TX TOMORROW.

SHORT RANGE HI RES MESO MODELS SHOW THE IDEA OF A LINE OF STORMS
FORMING IN C TX THIS AFTERNOON. THERE ARE THE BEGINNING OF STORMS
IN THE NW HILL COUNTRY BACK TOWARDS C TX SO THIS SCENARIO MAY BE
TAKING SHAPE. NAM/GFS SHOW SOMETHING SIMILAR WITH THIS LINE OF
STORMS REACHING THE AREA DURING THE MORNING HOURS ON FRIDAY.
EXPECT TO SEE STORMS STILL FORMING OFF THE GULF IN WARM ADVECTION
PATTERN AS WELL AS THESE STORMS MOVING INTO THE AREA FROM THE NW.
INCREASED POPS TO 80 PERCENT WITH MENTION OF HEAVY RAINFALL SINCE
IT APPEARS SEVERAL PARAMETERS WILL BE WORKING TOGETHER TO INCREASE
HEAVY RAINFALL POTENTIAL. OVERALL THINK 1 TO 3 INCHES OF RAIN AREA
WIDE LOOKS GOOD. IT IS THE ISO POCKETS OF 5 INCHES THAT MAY BE
POSSIBLE THAT COULD CAUSE FLOODING PROBLEMS. RIGHT NOW WILL HOLD
OFF ON FLASH FLOOD WATCH BUT THIS WILL BE MONITORED THROUGHOUT
LATER FORECAST CYCLES. BASED ON RECENT RAINFALL AMOUNTS...SOME
AREAS MAY BE MORE PRONE TO FLOODING THAN OTHERS SO WILL HANDLE
EACH CASE INDIVIDUALLY FOR NOW.

WHILE A LOW PROBABILITY..THERE STILL COULD BE AN IMPACT FROM
BRIEF TROPICAL FUNNELS AND TORNADOES FRIDAY MORNING. LOW LEVEL
WIND FIELDS INCREASE WITH 925MB WINDS OF 20-25 KTS AND 850MB WINDS
OF 25-30KTS BY 12Z FRI. LOW LEVEL 0-1KM BULK SHEAR VALUES OF
15-20KTS WILL BE PRESENT WITH LOW LCL HEIGHTS. QUITE POSSIBLE THAT
LOW TOPPED CELLS COULD BEGIN TO ROTATE ESPECIALLY THOSE COMING OFF
THE GULF OF MEXICO. THIS MEANS THERE IS THE POTENTIAL ALTHOUGH
SMALL FOR BRIEF WEAK TORNADOES IN SOME OF THESE STORMS THAT CAN
UTILIZE THE LOW LEVEL SHEAR. SPC HAS A 2% PROBABILITY FOR
TORNADOES IN THE AREA PRIMARILY FOR THIS REASON.

WEAK FRONTAL BOUNDARY WITH THIS SYSTEM SHOULD STALL FRIDAY AND
LINGER INTO SATURDAY. STILL PLENTY OF MOISTURE AROUND ON SATURDAY
SO POSSIBLE TO GET MORE THUNDERSTORM ACTIVITY WITH HEAVY RAINFALL
POTENTIAL. UPPER LEVEL SUPPORT WILL BE LESS AS THE UPPER LEVEL
SHORT WAVE TROUGH AXIS MOVES OUT OF THE AREA FRI NIGHT. LOOKS LIKE
CONVECTION MAY BE MORE MESOSCALE FORCED WITH ANY LINGERING
BOUNDARIES AS A FOCUS. FOR NOW SINCE THERE IS NOT MUCH UPPER LEVEL
SUPPORT...WILL KEEP POPS AROUND 30/40 PERCENT.

SUNDAY INTO THE REST OF THE WEEK THE UPPER LEVEL PATTERN LOOKS
MORE SUMMER LIKE WITH HIGHER 500MB HEIGHTS. UPPER LEVEL RIDGE
LOOKS TO DEVELOP OVER NEW MEX SUN INTO MON. WHILE THE RIDGE
EXPANDS MON INTO TUE...IT ALSO MOVES OVER THE C ROCKIES SO THE NET
EFFECT IS TO KEEP HEIGHTS RELATIVELY THE SAME GOING INTO THE
MIDDLE OF THE WEEK. MODELS SHOW A WEAKNESS IN THE RIDGE ALONG THE
N GULF COAST SO POSSIBLE THAT WITH ANY LINGERING HIGHER
MOISTURE...AFTERNOON STORMS WILL BE POSSIBLE. WILL KEEP POPS ON
THE LOW END OF 10/20 DURING THIS TIME FRAME BUT LOOKS LIKE AN ISO
STORM OR TWO COULD FORM IN THIS PATTERN. MAX TEMPS ARE A BIT
TRICKY BUT WILL KEEP WITH MID 90S FOR NOW. MAX TEMPS COULD BE A
DEGREE OR TWO COOLER SHOULD THERE BE A SIGNIFICANT RAIN EVENT THAT
KEEPS GROUNDS MORE SATURATED.

[unome]

80% :) highs around 90 :) mid-July... my kind of summer :)

[txflagwaver]

Looks like most of the rain will stay North of me..

On another note, is it just me or does there seem to be more lightning strikes lately? I mean they happen..but it seems like more recently...

[jasons2k]

Sure looked promising a couple of hours ago, but everything falls apart when it gets close to my place. Maybe later tonight/tomorrow will be better.

[jasons2k]

From Jeff Lindner:

Flash Flood Watch issued until 700pm Friday for most of SE TX.

An extremely moist air mass will combine with an upper level disturbance and stalling boundaries across the region to produce numerous slow moving thunderstorms capable of producing excessive rainfall.

Current thinking is that ongoing activity from College Station to Huntsville will weaken over the next few hours only to be replaced by new development in the midnight-600am time period. This new development is expected to slowly drift SSE across the region with the potential for heavy rainfall. Extensive moisture levels in a nearly tropical air mass along with slow storm motions support a threat for excessive short term rainfall rates of 1-3 inches per hour.

Any cell training could result in significantly higher rates as seen across N TX this morning. Widespread rainfall amounts of 2-3 inches is likely with isolated totals upwards of 5 inches or more in isolated locations.

Excessive short term rainfall rates will have the potential to produce rapid urban street flooding and rises on area watersheds.

[Andrew]

Flash flood warning for Bryan college station. Estimates of 3 to 5 inches has fallen. Reports of roads flooding and high water rescues.

[Ptarmigan]

I could see flooding a huge problem from the heavy rain.

[unome]

watches are up !

http://www.srh.noaa.gov/hgx/

http://www.texasstormchasers.com/2014/0 ... -possible/

[unome]

NESDIS

http://www.ospo.noaa.gov/data/atmospher ... 80141.html

FOR TX...HAVE INCREASING CONCERNS FOR SHORT TERM(NEXT SEVERAL HOURS) HEAVY RAINFALL THREAT CENTERED NEAR THE FWD-HGX-EWX CWA BORDER WHERE ACTIVITY WHICH INITIALLY BEGAN FARTHER TO THE E AS PART OF AN INTERSECTION BETWEEN SEA BREEZE CONVECTION AND THE FRONTAL BOUNDARY HAS RECENTLY SHOWN SIGNS OF BACK BUILDING AND MAY POTENTIALLY TRAIN FOR A FEW HOURS DURING TIME WHEN MEAN FLOW IS ALIGNED ROUGHLY PARALLEL TO BOUNDARY AND AXIS OF CONVECTION AND PRIOR TO LLJ VEERING LATER IN THE NIGHT AND FOCUSING MORE ON AREAS FARTHER TO THE EAST. THE ACTIVITY APPEARS TO BE FEEDING OFF OF A REGION OF HIGHER INSTABILITY/CAPE ALONG AND JUST S OF THE BOUNDARY PER THE GOES SOUNDER PRODUCTS. AT THIS TIME, ORGANIZATION IS NOT EVIDENT THOUGH WITH OVERALL COVERAGE INCREASING IT IS NOT OUT OF THE QUESTION THAT A RELATIVELY SMALL COMPLEX MAY BRIEFLY ORGANIZE PRIOR TO ACTIVITY SHIFTING TO THE EAST AND SOUTHEAST. AT THIS TIME, BELIEVE LOCALIZED ADDITIONAL LOCALIZED TOTALS OF 2-4" ARE POSSIBLE IN THIS REGION WITH EVEN SOME POTENTIAL FOR ISOLATED AMOUNTS EXCEEDING 4" GIVEN THE RAINFALL EFFICIENCY AND THE DEVELOPING SATELLITE SIGNATURE. SEE GRAPHIC ON THE INTERNET OUTLINING THE THREAT AREA IN APPROX 10 MINUTES.

[Andrew]

Yea it is really wet across the area. Pwats are all the way up to 2.3 inches which is +2 standard deviation. Currently the surface boundary is right over college stations, slowly sinking South. The hrrr suggests a lot of training could occur tonight over much of SE Texas, with msc development possible out west. Active night ahead.

[jasons2k]

By the way, my email sorted by subject shows the last Flash Flood Watch email I got from Jeff was from May 10, 2013. There is another from January 7, 2013 for a total of two last year.

Then the next previous one is from July 27, of 2007. Wow...It's been awhile...

[Ptarmigan]

Yea it is really wet across the area. Pwats are all the way up to 2.3 inches which is +2 standard deviation. Currently the surface boundary is right over college stations, slowly sinking South. The hrrr suggests a lot of training could occur tonight over much of SE Texas, with msc development possible out west. Active night ahead.

I would not be surprised if some areas see up to 15 inches of rain, especially in light of early this morning in North Texas.

[Paul Robison]

From Jeff Lindner:

Flash Flood Watch issued until 700pm Friday for most of SE TX.

An extremely moist air mass will combine with an upper level disturbance and stalling boundaries across the region to produce numerous slow moving thunderstorms capable of producing excessive rainfall.

Current thinking is that ongoing activity from College Station to Huntsville will weaken over the next few hours only to be replaced by new development in the midnight-600am time period. This new development is expected to slowly drift SSE across the region with the potential for heavy rainfall. Extensive moisture levels in a nearly tropical air mass along with slow storm motions support a threat for excessive short term rainfall rates of 1-3 inches per hour.

Any cell training could result in significantly higher rates as seen across N TX this morning. Widespread rainfall amounts of 2-3 inches is likely with isolated totals upwards of 5 inches or more in isolated locations.

Excessive short term rainfall rates will have the potential to produce rapid urban street flooding and rises on area watersheds.

Drama?

[unome]

http://www.srh.noaa.gov/hgx/?n=brief_support