April - Ends on Mild Note

[South_Texas_Storms]

Will April showers bring us some May flowers this year? Gosh I hope so!

[Andrew]

Mid level flow on next week's system still looks like it will be from the SW which could cause some capping issues. Time will tell I suspect.

[Ptarmigan]

Mid level flow on next week's system still looks like it will be from the SW which could cause some capping issues. Time will tell I suspect.

Sometimes flow from the southwest gives us moisture.

[srainhoutx]

There remains some uncertainty in the final evolution of a cut off upper low expected to enter the California Coast on late Sunday into Monday as well as the trough axis that will develop and open up as the system moves onshore and translates E into the Four Corners Region next Tuesday. A split flow pattern with a deep Northern stream Canadian storm system will drop SE as a deep trough remains across the eastern half of the US. There are indications that yet another strong push of Canadian air will drop S into the Plains setting the stage for increased rainfall and storms across the Southern Plains as the Polar front moves back N and stalls this weekend. The fly in the ointment continues to be just where that Polar front will be located and just how much capping issues can be overcome as a dry line develops across W Texas. The indications are the closed upper low that moves on shore will shear out early next week as a stronger upper low becomes established near the Great Lakes extending toward the NE, but embedded disturbances may well ride along the Southern jet that extends from Hawaii on E. There also are signals that a larger upper low will slowly translate E from the Pacific later next week. It does appear that another cold surge will sweep across Texas near the middle of next week and hopefully bring some much needed rainfall across our drought parched Region.

00Z Euro Ensemble Mean:

06Z GEFS:

7 Day QPF:

[srainhoutx]

Morning e-mail from Jeff:

After weeks of dry weather….the area has entered into an active state.

Thunderstorms yesterday afternoon affected areas mainly east of a line from College Station to Hempstead to Sugar Land to Galveston. Several reports of large hail were noted and good soaking rainfall.

I am hard pressed to call the boundary which moved through late yesterday helping to spark the storms a cool front, but will go with that for now as dewpoints have in fact fallen off some and drier air over N TX is shifting slowly southward. Short break in the active pattern today will be replaced with widespread thunderstorms on Tuesday afternoon into Wednesday.

Powerful upper level storm system offshore of CA this morning will begin to move inland over the next 12-24 hours and this will result in increasingly SW flow aloft over TX instead of NW which we had over the weekend. Low level moisture which has been scoured out of the region (but not far) by the Sunday storms is poised to make a strong return by this evening as pressures begin to lower out over W TX and winds turn more SE instead of NE and E. Should see low to mid 60 degree dewpoints return to the region this evening/overnight. Air mass will begin to destabilize Tuesday with heating and the approach of a low amplitude southern stream impulse in the sub-tropical jet. Brunt of lift with this disturbance should arrive after dark Tuesday and focus across the upper TX coastal waters into the coastal counties. Potential is for a coastal front to form up near/just offshore of the upper coast and act as a focus for thunderstorm development. While this is playing out the main storm system currently just off the W coast of the US will move into the four corners area and into W TX by early Wednesday. Strong and widespread upper level lift and splitting of the jet stream structures on the east side of this feature will promote vigorous thunderstorm development first over W and SW TX and then spreading eastward. Models are in decent agreement on a large scale MCS (meso convective system or thunderstorm complex) to form in the areas east of Big Bend to north of Del Rio and extending northward to near Midland. This complex will move ESE into the increasing low level jet overnight Tuesday into Wednesday. It is uncertain how fast this complex will move toward coastal TX, but the initial severe threat Tuesday afternoon over SW TX should weaken Tuesday night with the loss of heating. Still feel that with good low level inflow over S TX feeding the system, the complex will make it all the way toward the coast by Wednesday morning.

Meso scale influences from outflow boundaries over the next few days may help to override large scale synoptic features and result in varying placements of convective developments. Global forecast models have the correct pattern and need ingredients for some heavy rainfall, but the meso scale can greatly alter what the global models “think” will happen. One such possibility is how much storm development occurs near/off the upper TX coast Tuesday night and does this “rob” good low level moisture inflow into the SW TX MCS.

Rainfall amounts should average 1-2 inches across much of the state of TX which will be much needed rainfall. Could see some higher amounts especially near the coast where a period of cell training could be possible Tuesday night and then again Wednesday morning with the main line. PWS rise to near 1.5-1.7 inches which is high, but not historic for early April. Dry grounds should be able to handle much of what falls, but urban areas could see some ponding under the heavier rain cores.

Sunday Storm Reports:

Panorama Village, Montgomery: 1.25 inch hail at FM 830 and I-45

11 SE of Conroe, Montgomery: tree fell on to pickup truck on FM 1485 near Grapeland

Morgan’s Point, Harris: 40mph outflow winds along leading edge gust front

Manvel, Brazoria: Dime size hail reported in Manvel

Galveston, Galveston: PORTS data recorded a 41mph wind gust at the Galveston North Jetty along thunderstorm gust front.

Freer, Duval: 4.25 inch diameter hail (softball) caused extensive damage across the towns of Freer and Benavides. Nearly all windows broken out of homes and all vehicle windshields shattered

[srainhoutx]

The GFS is suggesting some near 3 inch amounts across parts of Central and SE Texas over the next 72 hours. Fingers crossed...

[srainhoutx]

Storm Prediction Center Day 2 Update:

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT MON APR 01 2013

VALID 021200Z - 031200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF WRN AND SWRN
TX INTO CNTRL TX...

...SYNOPSIS...

BLOCKING PATTERN WILL SLOWLY BEGIN THE PROCESS OF BREAKING DOWN AS
THE PROMINENT UPPER LOW CENTERED OVER SERN ONTARIO ADVANCES SLOWLY
EAST. THE SRN STREAM CUTOFF LOW CURRENTLY OVER THE GREAT BASIN WILL
MOVE SLOWLY SEWD...REACHING THE SRN ROCKIES LATE TUESDAY NIGHT. AT
SFC THE WRN EXTENTION OF COLD FRONT SITUATED FROM THE TN VALLEY WWD
INTO THE SRN HIGH PLAINS WILL CONTINUE SWD THROUGH TX.

...WRN AND SWRN THROUGH CNTRL TX...

UPPER 50S-LOW 60S BOUNDARY LAYER DEWPOINTS WILL ADVECT THROUGH MUCH
OF REMAINDER OF PRE-FRONTAL WARM SECTOR BY TUESDAY CONCURRENT WITH
EWD ADVECTION OF EML PLUME. THESE PROCESSES SHOULD CONTRIBUTE TO
1500-2000 J/KG MLCAPE OVER PART OF WRN AND SWRN TX WHERE STEEPER
LAPSE RATES AND STRONGER DIABATIC HEATING IS EXPECTED...WITH
1000-1500 J/KG FARTHER EAST INTO CNTRL/ERN TX. A FEW STORMS WILL
LIKELY BE ONGOING WITH SOME THREAT FOR HAIL ALONG AND NORTH OF THE
BOUNDARY FROM PORTIONS OF N TX INTO OK. OTHER STORMS ARE EXPECTED TO
DEVELOP ALONG OR NORTH OF STRONGER FRONTAL SURGE OVER WRN TX AS WELL
AS OVER THE HIGHER TERRAIN OF SWRN TX AS THE BOUNDARY LAYER
DESTABILIZES AND THE CAP WEAKENS DURING THE AFTERNOON. VERTICAL WIND
PROFILES WITH 30-35 KT EFFECTIVE SHEAR...STEEP LAPSE RATES AND
MODERATE INSTABILITY WILL SUPPORT A THREAT OF LARGE HAIL AND LOCALLY
STRONG TO DAMAGING WIND GUSTS.

OTHER STORMS MAY DEVELOP FARTHER EAST IN WARM SECTOR OVER CNTRL AND
ERN/SERN TX DURING THE AFTERNOON AND EVENING WHERE THE CAP SHOULD BE
WEAKER AND WHERE DEEPER ASCENT MAY BE AUGMENTED BY A WEAK SRN STREAM
IMPULSE. THE SHEAR/INSTABILITY PARAMETER SPACE APPEARS MORE MARGINAL
IN THIS REGION...BUT VERTICAL SHEAR MAY BECOME SUFFICIENT FOR A FEW
STORMS TO DEVELOP UPDRAFT ROTATION WITH THE APPROACH OF THE MID
LEVEL IMPULSE.

..DIAL.. 04/01/2013

[jasons2k]

I've been watching for a surprise too - it is humid and cap shouldn't be an issue. There may be just enough of a leftover boundary + slight sea breeze to kick something off, somewhere.

I had a nice .51" yesterday to start things off. Cheers to a better April.

[Katdaddy]

Finally we have lots rain in the forecast for SE TX. 1-2" rainfall totals with 3-4" in isolated areas. 70% chance of heavy rain Tuesday night and Wednesday. Some storms may be strong and street flooding may become a concern.

[Karen]

I really like the facebook post. Can that keep on going I cannot get into the forum on my phone but I can get facebook.

[srainhoutx]

I really like the facebook post. Can that keep on going I cannot get into the forum on my phone but I can get facebook.

We are going to utilize and update our KHOU Board facebook and twitter pages frequently. We realize that many of our members are well connected to these social media tools and we gained over 200 new 'friends' with the Weather Forum being down.

[Andrew]

I really like the facebook post. Can that keep on going I cannot get into the forum on my phone but I can get facebook.

Yea that was my bad Karen. I was supposed to be more active on the social network side but I just got so busy with other stuff. From now on out I will definitely try and keep in touch with that more. Srain did an excellent job maintaining it during the down time. Y'all make sure to get on my butt if I slack.

[CAK]

Can I get a link to the Khou weather facebook page. I cant seem to find it doing a regular facebook search.

[Andrew]

Can I get a link to the Khou weather facebook page. I cant seem to find it doing a regular facebook search.

We just transitioned to a new page and the URL is the following:

https://www.facebook.com/KHOU.Forum

[srainhoutx]

Rain/storm chances increasing throughout the day. Central Texas folks need to keep a close eye on the sky with large hail and gusty winds being the primary threat.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0727 AM CDT TUE APR 02 2013

VALID 021300Z - 031200Z

...THERE IS A SLGT RISK OF SVR TSTMS TODAY INTO TONIGHT ACROSS PARTS
OF CENTRAL AND SOUTHERN TEXAS...

...SYNOPSIS...
WITHIN THE PREVAILING SPLIT MID-LATITUDE WESTERLIES...MODELS
INDICATE THAT THE MAIN SHORT WAVE IMPULSE...WITHIN THE PROMINENT
NORTHERN BRANCH TROUGH OVER THE EASTERN U.S...WILL SLOWLY PROGRESS
EASTWARD INTO AND THROUGH THE CANADIAN MARITIMES DURING THIS
FORECAST PERIOD. AS THIS OCCURS...THE TRAILING EDGE OF CYCLONIC
NORTHERN STREAM FLOW IS EXPECTED TO SHIFT EAST OF THE MID/UPPER
MISSISSIPPI VALLEY. AT THE SAME TIME...THE TRAILING SOUTHERN BRANCH
CLOSED LOW/TROUGH IS FORECAST TO SLOWLY DIG THROUGH THE FOUR CORNERS
STATES...AS UPPER RIDGING BUILDS INTO CALIFORNIA...AHEAD OF THE NEXT
SIGNIFICANT SOUTHERN STREAM IMPULSE ADVANCING ACROSS THE EASTERN
PACIFIC. TO THE SOUTH AND EAST OF THE FOUR CORNERS TROUGH...BROADLY
CYCLONIC FLOW IS EXPECTED TO PERSIST ACROSS THE MEXICAN
PLATEAU...WHILE DEVELOPING EASTWARD ACROSS THE LOWER RIO GRANDE
VALLEY INTO THE WESTERN GULF COAST REGION.

SEVERAL WEAK/SMALLER SCALE IMPULSES WITHIN THIS LATTER REGIME MAY
CONTRIBUTE TO CONVECTIVE POTENTIAL TODAY ACROSS PARTS OF THE CENTRAL
AND SOUTHERN PLAINS...WHERE LOWER LEVELS REMAIN RELATIVELY
MOIST...AND MID-LEVEL LAPSE RATES REMAIN RELATIVELY STEEP. SEVERE
WEATHER POTENTIAL...HOWEVER...WILL BE COMPLICATED BY A DEEPENING
COLD INTRUSION ACROSS THE CENTRAL INTO SOUTHERN HIGH PLAINS. THIS
AIR IS ASSOCIATED WITH MUCH MORE EXPANSIVE SURFACE RIDGING EXTENDING
SOUTHEASTWARD OUT OF CENTRAL CANADA THROUGH THE EASTERN GULF OF
MEXICO...AND SOUTH ATLANTIC COASTAL AREAS...IN THE WAKE OF THE
NORTHERN BRANCH TROUGH.

...CENTRAL/SOUTHERN PLAINS...
NEAR/NORTH OF THE SURFACE FRONTAL ZONE...LOW POTENTIAL FOR
THUNDERSTORMS CAPABLE OF PRODUCING SEVERE HAIL MAY LINGER AS FAR
NORTH AS THE RED RIVER VALLEY AND PARTS OF NORTH CENTRAL TEXAS THIS
MORNING. MID-TROPOSPHERIC WARM ADVECTION DOWNSTREAM OF THE DIGGING
SOUTHERN BRANCH TROUGH MAY ALSO CONTRIBUTE TO STORMS CAPABLE OF
PRODUCING SOME HAIL LATER TONIGHT ACROSS PARTS OF THE TEXAS
PANHANDLE AND SOUTH PLAINS. HOWEVER...AS THE DEPTH OF THE COLDER
AND DRIER SURFACE-BASED LAYER INCREASES...CAPE IS CURRENTLY EXPECTED
TO DECREASE ENOUGH THAT THE RISK FOR SEVERE HAIL WILL REMAIN BELOW
SLIGHT RISK PROBABILITIES.

FARTHER SOUTH...GUIDANCE IS SUGGESTIVE THAT A WEAK IMPULSE MAY
CONTRIBUTE TO CONVECTIVE DEVELOPMENT DURING THE DAY TODAY WITHIN A
BROAD WARM FRONTAL ZONE NEAR MID/UPPER TEXAS COASTAL AREAS. THE
BOUNDARY LAYER ACROSS THIS REGION IS INCREASINGLY MOIST...WITH MID
TO UPPER 60S SURFACE DEW POINTS CONTRIBUTING TO SIZABLE CAPE. AS
MODEST SOUTHERLY 850 MB FLOW STRENGTHENING TAKES PLACE BENEATH 30+
KT WEST SOUTHWESTERLY 500 MB FLOW...VERTICAL SHEAR PROFILES MAY
BECOME SUFFICIENT FOR A FEW SEVERE STORMS...INCLUDING ISOLATED
SUPERCELLS.

OTHERWISE...FORCING FOR CONVECTION TO THE WEST REMAINS
UNCLEAR...EXCEPT FOR THE MOIST UPSLOPE REGIME ACROSS THE HIGHER
TERRAIN WEST OF THE RIO GRANDE RIVER INTO THE DAVIS MOUNTAINS AREA
OF SOUTHWEST TEXAS. THE ENVIRONMENT ACROSS THIS REGION APPEARS
CONDUCIVE TO SUPERCELLS...WHICH MAY TEND TO PROPAGATE EAST
SOUTHEASTWARD OFF THE HIGHER TERRAIN INTO TEXAS. THERE IS SOME
SIGNAL AMONG THE MODEL DATA THAT LARGE-SCALE FORCING FOR UPWARD
VERTICAL MOTION COULD CONTRIBUTE TO THE UPSCALE CONVECTIVE GROWTH OF
A MESOSCALE CONVECTIVE SYSTEM ACROSS PARTS OF SOUTH CENTRAL TEXAS
LATE THIS EVENING. IF THIS OCCURS...THE ENVIRONMENT SHOULD BE
CONDUCIVE TO THE RISK FOR DAMAGING WIND GUSTS AND LARGE HAIL.

..KERR/LEITMAN.. 04/02/2013

[srainhoutx]

Rain and storms chances are looking hopeful for Central and SE Texas the next 24-36 hours or so. It also appears more Spring storms may be on the way early next week as well, if the models are correct. Fingers Crossed!

[jasons2k]

The setup is definitely a little odd today. It feels chilly at my house, even though my dew point is 61, like the 'front' leftover from Saturday night is still here. Strangely, it's isolated though. I have stiff NE winds, while other locations all around me have winds out of the southeast. Just above the surface, I can see winds are from the SE, like the LLJ is developing.

Anyway, I have a feeling with some heating and the jet mixing down, it will all wash out this afternoon setting the stage for later on. It will be an interesting day to watch this all unfold.

[srainhoutx]

The updated GFS is suggesting 1-2 inches of rainfall for portions of Central/SE Texas with isolated higher amounts possible over the next 36 hours.

[srainhoutx]

Storm Prediction Center Update:

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT TUE APR 02 2013

VALID 021630Z - 031200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER A LARGE PART OF SRN AND
CNTRL TX...

...SYNOPSIS...
THE LARGE SCALE PATTERN LIKELY WILL CONTINUE TO SHOW MINIMAL CHANGE
THIS PERIOD AS SLOWLY-PROGRESSIVE SPLIT FLOW PATTERN PERSISTS OVER
THE WRN AND CNTRL STATES...IN WAKE OF DEEP VORTEX OVER NEW
ENGLAND/SRN QUE. LOW-LVL WARM ADVECTION/UPR LVL DIVERGENCE WILL
CONTINUE OVER MUCH TX AND THE WRN GULF CST REGION...DOWNSTREAM FROM
FOUR CORNERS UPR LOW. AT THE SAME TIME...DIVERGENCE/ASCENT WILL
INCREASE OVER S TX LATER TODAY...AND OVER THE NWRN GULF THROUGH
TNGT...AS SRN STREAM IMPULSE NOW OVER NW MEXICO/NRN SONORA TRACKS E
TO THE BIG BEND REGION BY EVE...AND INTO LA EARLY WED.

AT THE SFC...SHALLOW POLAR FRONT EXPECTED TO CONTINUE ADVANCING S
ACROSS W TX TODAY. THE S TO SE ADVANCE OF THE BOUNDARY SHOULD BE
MORE GRADUAL WITH EWD EXTENT ACROSS THE LWR PLNS AND HILL COUNTRY.
BY EVE THE FRONT SHOULD ARC NEWD FROM N OF THE BIG BEND REGION INTO
A WEAK WAVE NEAR DFW. A SERIES OF WEAKER BOUNDARIES NOW EXTENDING
ROUGHLY WNW/ESE ACROSS E TX INTO THE WRN GULF SHOULD FURTHER WEAKEN
AS LOW-LVL ESE FLOW PERSISTS ACROSS REGION.

COMBINATION OF MOIST...LOW-LVL UPSLOPE FLOW...SFC HEATING...
APPROACHING SRN STREAM DISTURBANCE...AND UPLIFT ALONG POLAR FRONT
TOGETHER SHOULD SUPPORT FAIRLY WIDESPREAD TSTM DEVELOPMENT ACROSS
PARTS OF CNTRL AND SRN TX LATER TODAY THROUGH EARLY WED. SOME OF
THESE STORMS COULD BECOME SVR.

...CNTRL/SRN TX LATER TODAY THROUGH EARLY WED...
MOIST UPSLOPE FLOW HAS CONTRIBUTED TO EXTENSIVE LOW-LVL CLOUD COVER
AHEAD OF COLD FRONT OVER MUCH OF SRN AND CNTRL TX.
NEVERTHELESS...MODERATE SFC HEATING WILL OCCUR IN PRE-FRONTAL AIR.
COUPLED WITH RELATIVELY COOL MID-LVL TEMPS AND FAVORABLY-TIMED
ASCENT ASSOCIATED WITH SONORAN UPR IMPULSE...EXPECT TSTMS TO FORM
OVER S CNTRL TX BY MID TO LATE AFTN...LIKELY PREFERENTIALLY ALONG
WRN FRINGE OF LOW CLOUD DECK/NEAR LEE TROUGH NOW EXTENDING NWD FROM
THE BIG BEND.

WHILE NOT PARTICULARLY STRONG /AROUND 35 KTS/...DEEP WLY SHEAR
SHOULD BE AMPLE FOR SUSTAINED STORMS/SUPERCELLS GIVEN RICHLY-MOIST
ENVIRONMENT /PW AOA 1.25 INCHES AND 850 MB DEWPOINTS ABOVE 12 C/ AND
ELY COMPONENT TO NEAR-SFC FLOW. OTHER STORMS MAY FORM ALONG AND
BEHIND SHALLOW POLAR FRONT OVER CNTRL AND N CNTRL TX. WHILE EXPECTED
FAIRLY EXTENSIVE STORM COVERAGE MAY RESULT IN SOME DEGREE OF
DESTRUCTIVE INTERFERENCE...AT LEAST SOME STORMS WILL HAVE THE
POTENTIAL TO PRODUCE LARGE HAIL AND LOCALLY DMGG WIND BEFORE
CONSOLIDATING INTO LARGER-SCALE CLUSTERS. THE STORM CLUSTERS SHOULD
MOVE/DEVELOP GENERALLY ESE TNGT THROUGH EARLY WED...THEREBY EXPOSING
MUCH OF THE TX GULF CSTL PLN /ESPECIALLY MIDDLE PORTIONS/ TO A RISK
FOR LOCALLY DMG WIND AND SVR HAIL. A RISK ALSO WILL EXIST FOR A
TORNADO OR TWO...CONDITIONAL ON FAVORABLE STORM-SCALE INTERACTIONS.


...NW TX/OK THROUGH EARLY WED...
FARTHER N...EPISODES OF ELEVATED TSTMS EXPECTED TO CONTINUE THROUGH
THE PERIOD N OF THE POLAR FRONT ACROSS NW TX AND MUCH OF OK.
DEEPENING OF POST-FRONTAL COLD AIR MASS AND DEVELOPMENT OF STRONGER
SFC-BASED STORMS FARTHER S SUGGEST THAT ELEVATED CAPE WILL REMAIN
TOO LIMITED TO POSE AN APPRECIABLE RISK FOR SVR HAIL.

..CORFIDI/ROGERS.. 04/02/2013

[Andrew]

Latest Jeff Lindner Update:

Storm system approaching TX midday with increasing chances for rain and thunderstorms this evening into Wednesday.

While synoptic scale models are in decent agreement with parameters to produce a good bout of much needed rainfall across the region, the meso scale features may help another story play out. Large scale upper level system over the SW US and strong short wave rounding through the base of this feature should eject ENE into SW TX over the next few hours spreading stronger lift into much of TX. Should begin to see an increase in the shower and thunderstorm activity from the SW to the NE by early evening as lift from the short wave comes to bear across the region. Main question is where storms develop. Appears some sort of coastal boundary (maybe a warm front) extends across the NW Gulf and then inland near Galveston and WNW toward Wharton. South of this boundary dewpoints have warmed into the upper 60’s and low 70’s while north dewpoints are in the upper 50’s and low 60’s. Increasing large scale lift combined with breaks in the cloud cover SW of SE TX over the coastal bend into SC TX should result in the development of storms by late afternoon which will spread into the region during the evening hours. High resolution short term models have varying solutions on where and when storms will develop and how they will track across the region. Previous runs really favored the coastal sections, while more recent runs are favoring the developing from CLL to Lufkin and then sagging a line slowly SE into the region overnight.

In addition to local development this afternoon/evening, stronger forcing arrives across SW and WC TX tonight and this should help ignite a complex of thunderstorms from W of Austin into NE MX which will track ESE toward the area toward daybreak on Wednesday. I am a little nervous with so much activity forecasted over SE TX tonight that eh approaching line will have much “fuel” to work with by the time it arrives Wednesday. Much depends on how much thunderstorm activity develops this evening and how far south any outflow boundaries drive which could cut off the good supply of Gulf moisture into any approaching storm complex.

Still feel a solid 1-2 inches of rainfall is likely across the area with PWs increasing toward 1.5 inches. Could see some higher amounts where training cells develop or where any lines slow, especially tonight. With grounds parched from the recent dry weather, much of what falls should soak in although some minor urban flooding issues will be possible under the heaviest rain cores.