May Weather Discussions. Drougnt Continues For Houston

[srainhoutx]

I'll post Jeff's e-mail here since it is of importance and we have not seen rain chances this good in sooooooo long...

After months of little to no rainfall across the region, Thursday will provide the next chance of hope for decent widespread soaking rains we desperately need.

Large upper level trough over the western US is slowly shifting eastward this morning with disturbances rotating through the SW flow aloft on the SE side of the main trough. Current disturbance is crossing the Rio Grande and is producing showers/thunderstorms from west of Corpus to south of San Antonio….a very good sign of things to come. This current disturbance will rotate ENE across central Texas this afternoon and given strong heating along the dry line, expect numerous strong to severe thunderstorms to develop along I-35 and show ENE toward SE TX. Strong capping still over the region will likely preclude much of this activity from reaching out area (maybe our western and northern counties will get a glancing blow).

Main event appears to be taking shape for Thursday into early Friday as main trough lifts into the plains and a strong short wave rotates through southern TX. Appears the stubborn cap of late will finally weaken to the point that surface parcels will be able to breach that mid level warm layer. In fact, for the first time in a long time the mid levels actually cool some mainly due to the track (more southerly) of the upper air disturbance. 250mb upper air winds also become increasingly divergent during the day on Thursday yielding increasing lift across the region. Surface dry line will remain stalled roughly along I-35 with moist SE winds feeding into this feature adding surface lift. Air mass will become unstable to very unstable by early to mid afternoon Thursday with CAPE values of 2500-3500 J/kg across the region. From the standpoint of the models and the thermodynamic indications everything looks go for thunderstorms and wetting rains…but that is model world not real world!

While all the above is looking good for decent rain chances across the entire area, we are suffering through one of the most severe droughts on record and the models may be trying to trend toward climatology more so than what is really happening over this region. While the track of the short wave does look favorable to produce rainfall, there is still questions as to how fast and how much the capping weakens over the area. Forecast models have been overdoing the weakening of the cap for the past several events which has left us high and dry.

It looks likely that some of us will indeed see rainfall on Thursday and Thursday night, but is it a widespread event or more scattered to isolated. Models have been trending wetter each day with this system unlike the past systems which they have trended drier as the verification time drew closer. Feel it is best to only go 30-40% across the entire area for Thursday which is lower than both the NAM and GFS guidance of 50-60% for this time period, rain chances may need to be raised significantly early Thursday after a review of what happens today in central TX and what kind of capping we look to have in place early tomorrow.

Rainfall Amounts:
Will follow the 4KM WRF model the closet showing a batch of thunderstorms forming WSW of Victoria late Thursday and pushing ENE all the way to near Beaumont by Friday morning…this brings wetting rains to a good part of the area. GFS shows 1.05 inches for KIAH during this period and HPC has been bouncing around with averages of .25-.75 of an inch. Given the deepening moisture profile and increasingly moist mid and upper levels (another recent change) any convection that develops will produce heavy rainfall. Will go with an average of .50 of an inch across the entire region with isolated amounts of 2-3 inches under the heavier cells.

Severe Threat:
Air mass will be primed for strong to severe thunderstorms. 4KM WRF is showing a fast moving almost bowing type display moving across the region Thursday night. Inflow off the Gulf of Mexico and increasing low level jet after dark Thursday will promote a damaging wind threat especially the later in the evening storms go. Initial storms will likely be more isolated and contain a greater damaging hail threat (this threat will likely be across our western counties or from College Station to Matagorda Bay) with the wind threat increasing east of that line after dark. SPC has the entire area outlooked for a slight chance of severe storms.

All in all it is probably our best shot at widespread rains in a long time…but will it actually happen…we shall know in the next 36 hours!

[srainhoutx]

A good sign for things to come...I can almost smell the rain...

[tireman4]

I just hope it does not hit the proverbial wall.....

[unome]

check out the storms in N Central TX http://www.atmo.arizona.edu/products/wx ... radar.html http://www.srh.noaa.gov/fwd/

how I miss a good storm...

[redneckweather]

It looks like the showers trying to move in from the west are hitting a dome of....southeast Texas dry hot crap!! Maybe the instability out that way right now will aid in eroding the CAP setting the stage for a damn good day of stormy weather tomorrow. Fingers crossed.

[srainhoutx]

A very lengthy Day 2 Update from SPC still has a Slight Risk for severe storms in SE TX. HPC has trimmed back rainfall amounts some due to capping issues, but still a descent chance of rain when we've gone months without any rainfall...

SPC:

...CENTRAL/SRN PLAINS...
SVR POTENTIAL EXISTS ACROSS BROAD SWATH OF CENTRAL CONUS FROM CORN
BELT TO S TX...AND SHOULD BECOME RATHER CONCENTRATED IN SOME AREAS
WITH LARGE HAIL...DAMAGING GUSTS AND A FEW TORNADOES.
HOWEVER...RISK REMAINS RATHER BROAD-BRUSHED ATTM GIVEN PRESENCE OF
SEVERAL CRUCIAL UNCERTAINTIES. SCATTERED TO LOCALLY NUMEROUS
AFTERNOON TSTMS MAY DEVELOP INVOF COLD FRONT/DRYLINE...AS WELL AS
ALONG BOUNDARIES IN WARM SECTOR THAT WILL BE INFLUENCED STRONGLY BY
ANTECEDENT CLOUDS/CONVECTIVE PROCESSES. SOME OF THIS ACTIVITY MAY
BE SUPERCELLULAR WITH DAMAGING HAIL AND A FEW TORNADOES POSSIBLE.

CONVECTION MAY BE ONGOING AT BEGINNING OF PERIOD OVER PORTIONS
IA/MO/AR AND PORTIONS ERN/SRN TX. ANY OF THIS ACTIVITY MAY MOVE EWD
INTO DIABATICALLY DESTABILIZING WARM SECTOR WITH FAVORABLY RICH
LOW-LEVEL MOISTURE...WEAKENING MLCINH AND INCREASING MLCAPE...AMIDST
FAVORABLE DEEP-LAYER SHEAR FOR SVR. OUTFLOW AND/OR
DIFFERENTIAL-HEATING BOUNDARIES LEFT BY EARLY ACTIVITY ALSO MAY
SERVE AS MESOBETA SCALE FOCI FOR SUBSEQUENT/AFTERNOON INITIATION
FARTHER W NEAR DRYLINE...FROM ERN KS TO N-CENTRAL/NE TX...DEPENDING
ON SPATIAL AND TEMPORAL EXTENT OF AFTERNOON DEGREE OF
DESTABILIZATION E OF EARLIER CLOUD/PRECIP PLUME.

FRONT AND DRYLINE SHOULD ACT AS WRN BOUND FOR SVR THREAT.
HOWEVER...THOUGH SMALL ON NATIONAL SCALE...CRUCIAL MESOSCALE
DIFFERENCES EXIST IN LONGITUDINAL POSITION OF DRYLINE AMONGST SREF
MEMBERS AND DETERMINISTIC/OPERATIONAL PROGS THAT CAST MARGIN FOR
UNCERTAINTY IN WRN EDGE OF SVR POTENTIAL. THEREFORE...RELATED
PROBABILISTIC GRADIENT IS NECESSARILY MORE LOOSE IN THIS FCST THAN
ACTUAL SFC THERMODYNAMIC GRADIENTS WILL BECOME. MOST FAVORABLE
WINDS ALOFT SHOULD EXIST SE OF MID-UPPER CYCLONE OVER FROM N TX TO
WRN OZARKS...AND ALSO...BENEATH SUBTROPICAL JET ACROSS S TX. MAIN
CONCERN IN LATTER AREA WILL BE STRENGTH OF CAPPING WITH SWD
EXTENT...WHICH MAY RESTRICT TSTM COVERAGE. BAND OF TSTMS MAY
PERSIST INTO LATE EVENING/OVERNIGHT ALONG/AHEAD OF COMMINGLED
FRONT/DRYLINE...FROM WRN GULF COASTAL PLAIN TOWARD LOWER MS VALLEY.
ANY SUCH ACTIVITY WOULD POSE GRADUALLY DIMINISHING SVR THREAT
THROUGH OVERNIGHT HOURS

[Kludge]

Lots of echoes... but is any of this making it to the ground anywhere around the area?

[srainhoutx]

There were some sprinkles earlier up here, but nothing right now. Those storms near Victoria may hold some hope for folks in the Western and Northern areas later this afternoon though. Fingers crossed!

[Sockmonkey]

Wha--what is this stuff?

It's wet! And it's falling from the sky! (At I-10 and the Beltway.)

Hmm...think I'll call it "Oobleck."

[jasons2k]

We just had a quick shower pass us at Bellaire & The West Loop. For a few seconds, it started to pour big, heavy tropical rain drops. And then suddenly, it just stopped. It was fun while it lasted and I think a good sign of things to come.

[CAK]

And there it goes, drying up every minute.
http://www.wunderground.com/radar/radbl ... g_off=9999

[jasons2k]

The problem today is we were cloudy all day and we didn't warm up enough to break through the cap. I think that's why the storms over the Houston area have been marginal. You can see the cells over Fort Bend and up near Brenham trying to get going, but it's just a tough road when we're cloudy and sitting in the upper 70's to near 80 across much of the area. If we had some sun earlier today, I would expect this little disturbance would be generating a pretty strong cluster of storms over us during rush hour. What this does indicate to me though is that the cap is withering away. The fact that storms are even trying to pop with just 77-82 degrees is a good sign IMO.

Don't fret. Tomorrow looks much better

[unome]

patience is a virtue (just not one of mine)

[Ptarmigan]

The problem today is we were cloudy all day and we didn't warm up enough to break through the cap. I think that's why the storms over the Houston area have been marginal. You can see the cells over Fort Bend and up near Brenham trying to get going, but it's just a tough road when we're cloudy and sitting in the upper 70's to near 80 across much of the area. If we had some sun earlier today, I would expect this little disturbance would be generating a pretty strong cluster of storms over us during rush hour. What this does indicate to me though is that the cap is withering away. The fact that storms are even trying to pop with just 77-82 degrees is a good sign IMO.

Don't fret. Tomorrow looks much better

Looks like the Cockroach Ridge is meeting its end.

[srainhoutx]

Sobering concerning the drought from HGX this afternoon:

LOOKS LIKE PARTS OF SOUTHEAST TEXAS WILL RECEIVE SOME RAIN OVER THE
NEXT 24 HOURS. HOBBY AIRPORT IS CURRENTLY AT 57 CONSECUTIVE DAYS
WITHOUT MEASURABLE RAIN (LAST RAIN MARCH 14TH). IT HAS BEEN SO DRY
THAT EVEN AN INCH OF RAIN WILL NOT CHANGE THE RECORDS. IT IS
CURRENTLY THE DRIEST OCT 1 THROUGH MAY 11TH FOR COLLEGE STATION AND
HOUSTON. COLLEGE STATION WILL NEED 2.93 INCHES OF RAIN TO MAKE THIS
THE SECOND DRIEST OCT 1 THRU MAY 11TH AND HOUSTON WILL NEED 1.64
INCHES OF RAIN TO MAKE THIS THE SECOND DRIEST OCT 1 THRU MAY 11TH.

SINCE FEB 1ST...CLL...IAH...HOU AND DANEVANG ARE THE DRIEST ON RECORD.
IT WOULD TAKE 2.18 INCHES OF RAIN AT HOU TO MAKE THIS PERIOD THE 2ND
DRIEST... 1.63 INCHES AT CLL...2.14 INCHES AT IAH AND 1.69 INCHES OF
RAIN AT DANEVANG TO MAKE THESE LOCATION THE 2ND DRIEST FEB THROUGH
MAY 11TH. NOT EXPECTING THAT MUCH RAIN SO IT LOOKS LIKE THE DRIEST
STRETCH OF WEATHER THIS AREA HAS EXPERIENCED IS LIKELY TO CONTINUE.

[Rip76]

The Hobby Airport to Galveston Cap, seems to have broken.
Looking at radar.

Ok maybe a little..

[redneckweather]

I had a 5 minute heavy shower right at dark when I was out messing around my garden. I stayed out in the rain and got completely soaked...loved every minute of it!! I even had puddles in my driveway. I don't think it was measurable but hell, I'll take it! More to come hopefully.

[wxman666]

SPC MCD 751.....


MESOSCALE DISCUSSION 0751
NWS STORM PREDICTION CENTER NORMAN OK
1125 PM CDT WED MAY 11 2011

AREAS AFFECTED...EAST-CENTRAL/SOUTH-CENTRAL TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 120425Z - 120530Z

AT LEAST AN ISOLATED SEVERE THREAT WILL LIKELY CONTINUE
OVERNIGHT...AND A NEW WATCH WILL NEED TO BE CONSIDERED FOR PORTIONS
OF SOUTH-CENTRAL/PERHAPS EAST-CENTRAL TX.

AN ONGOING SEVERE TSTM NEARING I-35 BETWEEN NEW BRAUNFELS/AUSTIN AS
OF 0415Z HAS EXHIBITED SOME SUPERCELL CHARACTERISTICS OVER THE PAST
HOUR. SIMILAR TO THIS STORM...IT IS CONCEIVABLE THAT ADDITIONAL
SURFACE BASED DEVELOPMENT WILL CONTINUE TO OCCUR ALONG A SOUTHEAST
SAGGING OUTFLOW BOUNDARY WITHIN A RATHER MOIST AND WEAKLY
CAPPED/VERY UNSTABLE AIRMASS...WITH CINH EXPECTED TO ONLY WEAKEN
OVERNIGHT PER SHORT TERM PROGS. WSR-88D VWP DATA FROM EWX/GRX
REFLECT AMPLE VEERING/WIND SPEEDS FOR UPDRAFT
ROTATION/SUPERCELLS...ACCENTUATED BY 150-200 M2/S2 0-1 KM
SRH...WHICH IMPLIES A BRIEF TORNADO CANNOT BE RULED OUT IN VICINITY
OF THE SURFACE BOUNDARY ASIDE FROM LARGE HAIL.
ADDITIONALLY...VARIOUS NUMERICAL GUIDANCE...SUCH AS THE 00Z NAM/GFS
AND VARIOUS 21Z SREF MEMBERSHIP...IMPLY AN EAST-SOUTHEASTWARD
CONTINUATION OF DEEP CONVECTION TOWARD THE MIDDLE/UPPER TX
COAST...AND/OR MORE SO THE POSSIBILITY OF ADDITIONAL DEVELOPMENT
LATE TONIGHT/EARLY THURSDAY IN VICINITY OF THE RIO GRANDE.

..GUYER.. 05/12/2011


ATTN...WFO...HGX...FWD...EWX...

LAT...LON 30959736 31739650 31629574 29279573 28800030 29810021
30359783 30959736




http://www.spc.noaa.gov/products/md/md0751.html

[unome]

Christmas Eve in May...

it's beginning to look a lot like Christmas

[texoz]

impressive looking meso at the border. Uvalde currently has a tornado warning.

http://forecast.weather.gov/wwamap/wwat ... %20Warning