March: Warm Days To End The Month With Isolated Showers

[srainhoutx]

The latest from HGX explains what we have been talking about for several day here on the board. This will be an event that will bring bouts of rainfall for several days and there still is some uncertainty regarding exactly who and where the heavier rainfall totals will fall....

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
354 PM CST THU MAR 8 2012

.DISCUSSION...
COLD FRONT IS MAKING FAST SWD PROGRESS. THIS BOUNDARY SHOULD BE
MOVING INTO NORTHERN PARTS OF SE TX AROUND 6PM...TO THE HWY 59
CORRIDOR AROUND 10PM AND OFF THE EXTREME SE COASTLINE SHORTLY
AFTER MIDNIGHT. MODELS DON`T HAVE THE BEST HANDLE OF THIS SHALLOW
COLD AIRMASS AND TRENDED FCST TIMING, WINDS, AND TEMPS CLOSER TO
THE FASTER TX TECH AND LOCAL WRF. HAVE A FEELING TEMPS MIGHT NEED
TO BE FURTHER LOWERED ESP NW ZONES. SHRA/TSTMS HAVE DEVELOPED
ALONG THE BOUNDARY AND EXPECT THESE TO MOVE INTO SE TX THIS EVENING.
MAY HAVE A SHORT TIME PERIOD FOR AN ISOLATED STRONG TO SEVERE STORM
ACROSS NRN COUNTIES THIS EVENING WITH HAIL BEING THE MAIN THREAT.
HIGHER RAINFALL TOTALS WILL LIKELY BE ACROSS NE PARTS BUT AM NOT
EXPECTING MUCH IF ANY OF A FLOOD THREAT WITH THIS FRONT. PERIODS
OF -RA WILL PERSIST THROUGH FRIDAY WITH MOISTURE OVERRUNNING THE
SHALLOW COLD AIR. NORTHERN PARTS OF THE AREA MAY SEE ANOTHER
1/4-1/2" DURING THE DAY AS THERE SHOULD BE A LLVL CONVERGENT ZONE
IN THE AREA WHICH COULD PROVIDE A FOCUS.

BASED ON THE MANY PHONE CALLS TODAY...THERE SEEMS TO BE QUITE A
BIT OF CONFUSION AND/OR MISCOMMUNICATION REGARDING RAINFALL &
FLOOD POTENTIAL THROUGH THE WEEKEND. LET`S SEE IF WE CAN BEGIN
CLEARING SOME THINGS UP. I BELIEVE MANY PEOPLE ARE SEEING POTENTIAL
4-DAY RAIN TOTALS BEING ADVERTISED AND POSSIBLY CONFUSING THAT
WITH THAT OF RAINFALL OCCURRING ON A SINGLE DAY OR SHORT TIME
PERIOD. THEY ARE DIFFERENT ANIMALS.

WE ARE CURRENTLY EXPECTING 2...AND POSSIBLY 3 ROUNDS...OF MODERATE
TO OCCASIONALLY HEAVIER RAINFALL EPISODES BETWEEN NOW AND SUNDAY
NIGHT:

1. TONIGHTS FRONT WILL BE ROUND NUMBER ONE.
2. MAY SEE AN UPPER LEVEL DISTURBANCE PUSH SW-NE ACROSS THE STATE
SATURDAY AFTERNOON AND SATURDAY EVENING. THE LATEST GUIDANCE
SUGGESTS THIS DISTURBANCE WILL PASS CLOSE TO (AND MORE LIKELY
JUST NORTH) OF THE NORTHERN PARTS OF SE TX.
3. EXPECT PROBABLY THE MORE SIGNIFICANT RAINFALL EPISODE TO OCCUR
ON SUNDAY IN ADVANCE OF THE MAIN UPPER TROF THAT WILL BE
APPROACHING THE AREA.

SO...THE GROUND WILL PROGRESSIVELY BECOME WETTER WITH TIME WITH
EACH SUBSEQUENT RAINFALL EPISODE. THE LOCATIONS THAT SEE THE
HIGHER RAINFALL AMOUNTS EARLY WILL BE MORE PRONE TO RUNOFF AND
FLASH FLOODING DURING THE LATER TIME PERIODS. AT THIS TIME
LOCATIONS GENERALLY NORTH AND WEST OF HIGHWAY 59 APPEAR TO BE IN
THE MORE FAVORABLE POSITION TO SEE THE HIGHER RAINFALL AMOUNTS
THROUGH THE WEEKEND.

FORECASTING PRECISE RAINFALL ACCUMULATIONS 3/4 DAYS OUT ARE JUST
AN EDUCATED GUESS AND WILL UNDOUBTEDLY EVOLVE WITH TIME. SLIGHT
DEVIATIONS OF SURFACE AND UPPER LEVEL FEATURES, TIMING AND
MOISTURE AVAILABILITY COULD ALTER RAINFALL AMOUNTS ONE WAY OR THE
OTHER. AVERAGE RAINFALL ACCUMULATIONS THRU THE WEEKEND (ADDING UP
#1-3 ABOVE) WILL PROBABLY AVERAGE ONE TO THREE INCHES. DUE TO
FORECAST UPPER LEVEL CONDITIONS...LOCALIZED 4-7" AMOUNTS (AGAIN
ADDING UP #1-3) ARE A POSSIBILITY DUE TO TRAINING.

AT THE CURRENT TIME...IT LOOKS LIKE SUNDAYS EVENT MAY CAUSE THE
HIGHER RAINFALL AMOUNTS AND WOULD BE THE DAY MOST CONCERNED ABOUT
POTENTIAL FLOODING - DUE TO POTENTIALLY SATURATED GROUNDS AT SOME
LOCATIONS. WE WILL CONTINUE TO MONITOR THE SITUATION AND EVALUATE
THE NEED FOR ANY WATCHES, ETC.

THIS SYSTEM SHOULD PUSH EAST OF THE REGION EARLY MONDAY BRINGING
AN END TO THE RAINFALL AND SETTING UP A WARM SPRING BREAK WITH
JUST A SLIGHTLY POSSIBILITY OF SOME ISO DAYTIME SHOWERS.

[Andrew]

Is there a place on the NWS site, or anywhere else, where you can find the forward motion of cold fronts?

I see the cold front is dipping southward and has just passed Lake Buchanan at 1:15pm, but not Waco yet. Trying to figure out when it will pass through Austin.

Also here are some good ones:

US_T.GIF

2012030822_metars_abi.gif

http://www.atmo.arizona.edu/products/wx ... 0mbwv.html

[Ptarmigan]

Looks like rain is developing west of Houston. Should be an interesting night.

[Belmer]

Upper 30s low 40s forecasted here in and around San Marcos tomorrow morning. I certainly wouldn't mind seeing a sleet pellet or two before I head to Houston tomorrow afternoon to begin my Spring Break!

[MESOMAN]

Total Bust so far. Hope it gets going overnight.

[Ptarmigan]

Total Bust so far. Hope it gets going overnight.

The calm before the storm. Not a bust yet. The January 9, 2012 storm did not form until after past midnight.

[Andrew]

Total Bust so far. Hope it gets going overnight.

Not a bust at all so far. The front was not supposed to spark widespread showers. It is when the system out west get closer and swings storms around when we will see all our rain.

[srainhoutx]

The over night guidance suggests and bit more close core upper low will remain well to our W with embedded short wave energy rotating beneath that U/L in the SW flow aloft for the next 48 to 60 hours. Over running showers with a chance of some stronger elevated storms look to increase mid day Friday near SE TX before another break in the action on Saturday. The 'heavier rains Saturday appear to be focused further W over Central TX and the Hill Country Lakes where the past events have missed and should benefit that region of our drought parched State, and that is a good thing.

The guidance had suggested that heavier storms/rains of Thursday, with the cold front passage, would remain to our N and E and that has be exactly what has happened and where Flood Advisories are in effect near Lufkin and on N and E. The NAM (WRF/NMM) continues to advertise a round of heavier elevated storms moving near the Houston Metro area Friday as short wave energy swings across the region heading ENE along the boundary. On Saturday, a surface wave of low pressure looks to develop near Rock Port and traverse NNE as the U/L creeps slowly E toward the Texas Panhandle. Additional short wave energy streams in from the W with over running showers developing again Saturday night into Sunday. As the U/L finally begins to trek NE across N TX/OK, a line of heavier showers/elevated storms appears to swing through as the frontal boundary begins retreating N decreasing aerial coverage of rains by Sunday evening, if guidance is correct. All in all things are unfolding as generally expected and we'll need to watch radar trends later today to see if training cells set up mainly along and W of the HWY 59 corridor.

[srainhoutx]

HGX Morning Update:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
416 AM CST FRI MAR 9 2012

.DISCUSSION...
COLD FRONT MOVED OFF THE COAST EARLY THIS MORNING AND COOLED US ALL
DOWN. SPOTTY AREAS OF LIGHT TO MODERATE RAIN ARE FOUND ACROSS PARTS
OF SOUTHEAST TEXAS AT 4 AM. HAVE MADE VERY LITTLE CHANGES TO THE FORECAST
PACKAGE WHICH CALLS FOR PERIODS OF RAIN/RAIN SHOWERS AND EMBEDDED THUNDERSTORMS
THROUGH SUNDAY. ALTHOUGH LOCALLY HEAVY RAINFALL WILL BE POSSIBLE WITH
ANY OF THE HARD TO TIME DISTURBANCES THAT MOVE ACROSS OUR AREA...IT APPEARS
THE STRONGEST DISTURBANCE AND BEST CHANCE FOR HEAVY RAIN SHOULD COME LATE
SATURDAY NIGHT THROUGH SUNDAY AFTERNOON AS THE MID/UPPER LEVEL LOW CURRENTLY
SPINNING ACROSS NEW MEXICO FINALLY EJECTS OFF TO THE NORTHEAST AND
HEADS TOWARDS THE GREAT LAKES AREA. SO FAR...HEAVIEST RAINFALL AMOUNTS
HAVE BEEN UP NORTH WITH TOTALS OF 2 TO 3 INCHES FROM AROUND THE CROCKETT
AREA EASTWARD TO THE APPLE SPRINGS AREA. STILL THINK THAT THROUGH
SUNDAY MOST OF SOUTHEAST TEXAS WILL AVERAGE 1 TO 3 INCHES WITH ISOLATED
AMOUNTS IN A 4 TO 7 INCH RANGE. WE WILL BE WATCHING FOR WHICH AREAS RECEIVE
THE MOST RAINFALL AS THESE EVENTS UNFOLD AND CONSIDER POSSIBLE FLOOD
WATCHES. ONCE THIS EVENTS COMES TO AN END...THE AREA WILL SEE A RETURN OF
WARM SPRING TIME WEATHER FOR MUCH OF NEXT WEEK WITH LOWS GENERALLY IN
THE 60S AND HIGHS GENERALLY IN THE UPPER 70S TO AROUND 80 AND LOW RAIN
CHANCES EACH DAY.

HERE ARE SOME RAINFALL RECORDS THAT HAVE THE POTENTIAL TO BE BROKEN OVER
THE NEXT THREE DAYS.

LOCATION TODAY SATURDAY SUNDAY

CLL ... 1.73 IN 1913 ... 1.51 IN 2008 ... 1.68 IN 1921
IAH ... 1.50 IN 1903 ... 3.23 IN 1926 ... 1.20 IN 1903
HOU ... 1.20 IN 1994 ... 1.03 IN 1944 ... 0.74 IN 1970
GLS ... 1.75 IN 1880 ... 3.97 IN 1903 ... 1.17 IN 1914

[unome]

their multimedia briefing today http://www.srh.weather.gov/hgx/?n=briefing should be updated either sat or sun

[ticka1]

Will the rain start progressing southward or is the majority of it going to be to our north?

[srainhoutx]

Will the rain start progressing southward or is the majority of it going to be to our north?

There is some short wave energy moving ENE in the SW flow near the Baja Region this morning. I suspect that feature will be a 'trigger' for showers and embedded storm development later today for areas N of the frontal boundary beginning in S Central TX and then traversing up the Coast. We will see. Thankfully the Hill Country is getting some much needed rain to replenish the Lakes where it is sorely needed.



DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0633 AM CST FRI MAR 09 2012

VALID 091300Z - 101200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
SPLIT FLOW WILL PREVAIL OVER THE CONUS...WITH THE MAIN BELT OF THE
WLYS PERSISTING FROM BC ACROSS S CNTRL CANADA INTO THE NERN U.S. A
FAIRLY STRONG SHORTWAVE TROUGH IN THIS FLOW WILL PROGRESS FROM THE
CNTRL GRT LKS TO OFF THE NEW ENGLAND CST BY THE END OF THE PERIOD.
IN THE WEAKER SRN STREAM...NM UPR LOW SHOULD RETROGRESS TO SE
AZ...ALLOWING HEIGHTS TO REBOUND ACROSS THE SRN PLNS/LWR MS VLY.

AT THE SFC...COLD FRONT ATTENDANT TO BOTH THE NM LOW AND THE NERN
TROUGH IS EXPECTED TO CONTINUE ADVANCING SE ACROSS THE NWRN GULF OF
MEXICO AND THE SERN STATES. THE BOUNDARY SHOULD WEAKEN AS IT
REACHES CNTRL FL EARLY SAT.

...FL AND ADJACENT SERN STATES TODAY...
EMBEDDED ELEVATED TSTMS WILL PERSIST THROUGH LATER THIS MORNING
NORTH OF COLD FRONT OVER THE NWRN GULF...SRN LA...AND SRN MS.
OTHERWISE...DIURNAL DESTABILIZATION COULD SUPPORT DEVELOPMENT OF
WDLY SCTD SFC-BASED SHOWERS/STORMS ALONG THE FRONT EWD TO THE S
ATLANTIC CST. HOWEVER...GREATER COVERAGE OF DIURNAL STORMS IS
EXPECTED FARTHER S OVER THE FL PENINSULA...WHERE MORE SIGNIFICANT
CONVERGENCE WILL EXIST ALONG SEA BREEZE BOUNDARIES. COMBINATION OF
SEASONABLY MOIST AIR /PW AOA 1.25 INCHES/ AND STRONG SFC HEATING
SHOULD BOOST SBCAPE TO AOA 1500 J/KG. WEAK SHEAR SHOULD LIMIT
UPDRAFT ORGANIZATION/STRENGTH.

...TX THROUGH EARLY SAT...
IT WILL REMAIN RELATIVELY MOIST AND UNSTABLE ATOP SHALLOW FRONTAL
INVERSION OVER CNTRL AND S TX THROUGH SAT. HEIGHTS WILL RISE
ALOFT...BUT UPR DIFFLUENCE WILL PERSIST E OF RETROGRESSING UPR LOW.
THIS SETUP MAY YIELD PERIODIC BOUTS OF ELEVATED CONVECTION/TSTMS.
WHILE A FEW UPDRAFTS MAY BECOME STRONG ENOUGH TO PRODUCE
HAIL...CLOUD LAYER SHEAR AND INSTABILITY EXPECTED TO REMAIN TOO WEAK
TO SUPPORT A RISK FOR SUSTAINED SVR STORMS.

[Snowman]

Alright I am tired of these little showers when is the big stuff moving in?

[Ptarmigan]

The over night guidance suggests and bit more close core upper low will remain well to our W with embedded short wave energy rotating beneath that U/L in the SW flow aloft for the next 48 to 60 hours. Over running showers with a chance of some stronger elevated storms look to increase mid day Friday near SE TX before another break in the action on Saturday. The 'heavier rains Saturday appear to be focused further W over Central TX and the Hill Country Lakes where the past events have missed and should benefit that region of our drought parched State, and that is a good thing.

The guidance had suggested that heavier storms/rains of Thursday, with the cold front passage, would remain to our N and E and that has be exactly what has happened and where Flood Advisories are in effect near Lufkin and on N and E. The NAM (WRF/NMM) continues to advertise a round of heavier elevated storms moving near the Houston Metro area Friday as short wave energy swings across the region heading ENE along the boundary. On Saturday, a surface wave of low pressure looks to develop near Rock Port and traverse NNE as the U/L creeps slowly E toward the Texas Panhandle. Additional short wave energy streams in from the W with over running showers developing again Saturday night into Sunday. As the U/L finally begins to trek NE across N TX/OK, a line of heavier showers/elevated storms appears to swing through as the frontal boundary begins retreating N decreasing aerial coverage of rains by Sunday evening, if guidance is correct. All in all things are unfolding as generally expected and we'll need to watch radar trends later today to see if training cells set up mainly along and W of the HWY 59 corridor.

Let'em have the rain. They need it.

[srainhoutx]

Alright I am tired of these little showers when is the big stuff moving in?

The 12Z GFS suggests Saturday afternoon through Sunday...

[Snowman]

Alright I am tired of these little showers when is the big stuff moving in?

The 12Z GFS suggests Saturday afternoon through Sunday...

Will it be one round of heavy rain or multiple rounds?

[wxman57]

Alright I am tired of these little showers when is the big stuff moving in?

Sunday looks like the best chance for heavy rain. The rain Saturday afternoon/evening may stay mostly to our north.

[ticka1]

Its 49 degrees and I got THUNDER here at the house! Didn't know we were going to have storms today!!!! And love this cold weather!!!!

[svrwx0503]

Decent amount of lightning associated with the shower and thunderstorm activity moving in from the west. There could be some small hail with with the stronger activity.

[srainhoutx]

Decent amount of lightning associated with the shower and thunderstorm activity moving in from the west. There could be some small hail with with the stronger activity.

The HPC is now mentioning SE TX in particular in their updated short term forecast discussions concerning heavy rainfall as well...

SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
328 PM EST FRI MAR 09 2012

VALID 00Z SAT MAR 10 2012 - 00Z MON MAR 12 2012

...ADDITIONAL MODERATE TO HEAVY RAINFALL IS EXPECTED ACROSS
SOUTHEAST TEXAS AND INTO THE ARKLATEX...

...AN ACTIVE PACIFIC TROUGH WILL KEEP UNSETTLED WEATHER IN THE
FORECAST FOR MUCH OF THE NORTHWESTERN U.S...


A MEANDERING UPPER LOW CENTERED OVER NORTH-CENTRAL MEXICO WILL
BRING ANOTHER BATCH OF SNOW TO MUCH OF NEW MEXICO THROUGH SATURDAY
EVENING. UNDERNEATH THIS LOW CENTER...BELOW NORMAL TEMPERATURES
WILL BE IN PLACE AS HIGHS IN THE 40S WILL BE COMMONPLACE ON
SATURDAY ACROSS A LARGE PORTION OF TEXAS. BY THE CONCLUSION OF THE
WEEKEND...A SYSTEM TO THE WEST WILL FINALLY HELP PUSH OUT THIS
STAGNANT DISTURBANCE WHERE IT SHOULD EVENTUALLY REACH THE CENTRAL
PLAINS BY LATE SUNDAY. BESIDES THE CHILLY CONDITIONS IN
PLACE...ENHANCED LOW-LEVEL MOISTURE EMANATING FROM THE GULF OF
MEXICO WILL KEEP A THREAT FOR MODERATE TO HEAVY RAINFALL IN THE
FORECAST OVER THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY.
THE HIGHEST RAINFALL AMOUNTS ARE EXPECTED FROM SOUTHEAST TEXAS UP
TOWARD THE ARKLATEX WHERE A POSSIBILITY OF FLOODING EXISTS FOR
SATURDAY EVENING INTO MUCH OF SUNDAY.