May: Isolated Showers To End The Month

[jasons2k]

Yep, Saturday. The field is bone dry now, but if there is training Friday night and into Saturday, it could be a problem.

I am in the same boat. We are planning a work party, outdoors, on Saturday from 10-2. We'll be doing several family/kids' activities that require a field, etc. So it can't be muddy for us, either.

I'm on the planning committee and the designated 'weather guru' to make yes or no calls for these things.

I have make a final go/no-go call by noon tomorrow as we have vendors contracted for services (who need advance notice).

Yeah, not a fun time to be me. I'm leaning heavily towards a 'no' at this point. I love to see the rain, but not for this event.

[wxman57]

12Z GFS indicates about 1/2" of rain from 4am to 10am Saturday then another 0.4" or so from 1pm-7pm. I think you should count on passing showers during the day on Saturday with a good possibility of a thunderstorm that would drop heavier rainfall. Late morning/early afternoon is also the time of the Houston art car parade downtown. Was planning on biking over there as I do every year. Maybe not this year...

[jasons2k]

Not following - it tops out at 50% overnight Thursday then drops to 30% on Friday. This does not line-up with their own discussion:

HOUSTON (IAH) 67 81 68 82 68 / 10 20 50 30 30

[Paul Robison]

Should we regard this "wet pattern" as a clear and present danger to life and property? Should Houstonians stock up on batteries and gasoline for generators?

[TexasBreeze]

You would think a hurricane was approaching...
Stock up for the upcoming tropical season instead.

[Paul Robison]

You would think a hurricane was approaching...
Stock up for the upcoming tropical season instead.

Well, Texas Breeze, the way the weather people are talking, you'd think a hurricane WAS coming. And some of these "damaging winds" they talk about COULD get that strong, you know.
BTW: Anyone have any opinons on what they think is going to happen when the rains come?

[CAK]

BTW: Anyone have any opinons on what they think is going to happen when the rains come?

Stuff will get wet...

[redneckweather]

Paul, I'm really not sure? Try this...when it starts to rain, go outside, stand out in the rain for awhile and let us know what happens.

[srainhoutx]

The Storm Prediction Center expands the Slight Risk for severe storms to include a large portion of Texas and Oklahoma including Central and SE Texas for today.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0717 AM CDT THU MAY 09 2013

VALID 091300Z - 101200Z

...THERE IS A SLGT RISK OF SVR TSTMS TODAY INTO TONIGHT ACROSS MUCH
OF THE SOUTHERN PLAINS INTO ADJACENT PORTIONS OF THE LOWER
MISSISSIPPI VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS TODAY ACROSS PARTS OF THE
MIDDLE MISSISSIPPI INTO LOWER OHIO VALLEY...

...SYNOPSIS...
UPPER TROUGHING APPEARS TO BE AMPLIFYING TO THE NORTHEAST OF A
BLOCKING MID-LEVEL HIGH CENTER LINGERING OVER THE PACIFIC NORTHWEST.
BUT A GENERALLY WEAK FLOW REGIME IS EXPECTED TO PERSIST ACROSS MUCH
OF THE U.S...AS THE ASSOCIATED CYCLONIC BELT OF STRONGER WESTERLIES
REMAINS NORTH OF THE INTERNATIONAL BORDER AREA THROUGH THIS PERIOD.
THE PRIMARY EXCEPTION WILL REMAIN ACROSS THE SOUTHERN PLAINS...NEAR
A STRONG ANTICYCLONIC HIGH-LEVEL JET WHICH HAS EMERGED FROM THE
SUBTROPICAL EASTERN PACIFIC. THIS FEATURE MAY WEAKEN SOME
TODAY...BUT A BELT OF MODERATELY STRONG CYCLONIC MID/UPPER FLOW
CONTINUES TO DEVELOP EASTWARD ACROSS NORTHERN BAJA AND THE NORTHERN
MEXICAN PLATEAU...AND IS FORECAST TO CONTINUE DEVELOPING EASTWARD
ACROSS TEXAS...WITH SEVERAL EMBEDDED SPEED MAXIMA.

WITHIN THE WEAK FLOW OVER THE MIDDLE OF THE COUNTRY...ONE WEAKENING
CYCLONIC MID-LEVEL CIRCULATION IS EXPECTED TO SHIFT EAST OF THE
MIDDLE MISSOURI VALLEY TOWARD THE SOUTHERN GREAT LAKES TODAY...WHILE
ANOTHER CONTINUES TO SHIFT EAST OF THE CENTRAL ROCKIES. WITHIN WEST
SOUTHWESTERLY FLOW TO THE SOUTHWEST OF THESE FEATURES...A COUPLE OF
CONVECTIVELY GENERATED CYCLONIC VORTICITY MAXIMA ARE EXPECTED TO
MIGRATE NORTHEASTWARD ACROSS THE MIDDLE MISSISSIPPI VALLEY...THROUGH
THE LOWER OHIO VALLEY...TO THE NORTH OF THE OHIO RIVER.

AT THE SAME TIME...A RETURN FLOW OFF THE WESTERN GULF OF MEXICO WILL
CONTINUE TO STEADILY INCREASE MOISTURE ACROSS THE SOUTHERN
PLAINS...LOWER HALF OF THE MISSISSIPPI VALLEY AND LOWER OHIO VALLEY.
THIS WILL SUPPORT THE DEVELOPMENT OF CONSIDERABLE THUNDERSTORM
ACTIVITY TODAY...AIDED BY DAYTIME HEATING.

MEANWHILE...A RISK FOR THUNDERSTORMS WILL CONTINUE WITH A PERSISTENT
MID-LEVEL CLOSED LOW...NOW CENTERED OVER THE NORTHERN MID ATLANTIC
COAST STATES...AND FORECAST TO SHIFT ACROSS SOUTHERN NEW ENGLAND
LATER TODAY/TONIGHT. AND THE ENVIRONMENT WILL REMAIN CONDUCIVE TO
SCATTERED MOSTLY DIURNAL THUNDERSTORM DEVELOPMENT ACROSS PARTS OF
THE ROCKIES...MUCH OF THE INTERMOUNTAIN WEST...AND THE SOUTHERN
CASCADES INTO THE SIERRA NEVADA.

...SOUTHERN PLAINS...
POTENTIAL CONVECTIVE EVOLUTION REMAINS UNCERTAIN TODAY ALONG AND
SOUTH OF A WEAK FRONTAL ZONAL EXTENDING FROM THE MID/LOWER MISSOURI
VALLEY INTO THE SOUTHERN HIGH PLAINS. BUT MODELS HAVE SIGNALED THAT
LARGE-SCALE FORCING ASSOCIATED WITH AT LEAST ONE SPEED MAXIMUM
MIGRATING NORTHEAST OF THE NORTHERN MEXICAN PLATEAU MAY CONTRIBUTE
TO A DEVELOPING CLUSTER OF STORMS ACROSS CENTRAL TEXAS BY MIDDAY.
THIS APPEARS SUPPORTED BY RECENT NEW STORM DEVELOPMENT EAST OF SAN
ANGELO. GIVEN THE STEEP MID-LEVEL LAPSE RATES PRESENT ACROSS THE
REGION...AND AT LEAST MODEST SHEAR...SEVERE HAIL MAY BE A THREAT
WITH STRONGER CELLS AS THEY SPREAD EASTWARD AND CONVECTION INCREASES
IN COVERAGE THIS MORNING. AS THE BOUNDARY LAYER ACROSS CENTRAL INTO
EASTERN TEXAS CONTINUES TO MOISTEN AND WARM...SUBSTANTIVE
INTENSIFICATION APPEARS POSSIBLE THIS AFTERNOON. AIDED BY
INCREASING VERTICAL SHEAR ASSOCIATED WITH STRENGTHENING MID-LEVEL
FLOW...ONE OR MORE ORGANIZED STORM CLUSTERS COULD EVOLVE WITH A RISK
FOR STRONG WIND GUSTS...IN ADDITION TO SEVERE HAIL.

OTHERWISE...SEVERE STORM POTENTIAL SEEMS MOST CERTAIN ALONG THE
DRYLINE...FROM PARTS OF THE EDWARDS PLATEAU NORTHWARD INTO ITS
INTERSECTION WITH THE COLD FRONT OVER SOUTHWEST OKLAHOMA OR
NORTHWEST TEXAS DURING THE PEAK HEATING AFTERNOON HEATING.
THERMODYNAMIC PROFILES CHARACTERIZED BY RATHER STEEP LOW THROUGH
MID-LEVEL LAPSE RATES AND LARGE CAPE ARE EXPECTED TO BE SUPPORTIVE
OF SUPERCELLS...SOME OF WHICH MAY PRODUCE VERY LARGE HAIL.

CONVECTIVE POTENTIAL REMAINS MORE UNCLEAR ALONG THE FRONT ACROSS
NORTHERN OKLAHOMA INTO WESTERN MISSOURI...AS CONVECTIVE OUTFLOW
ASSOCIATED WITH A WEAKENING MESOSCALE CONVECTIVE SYSTEM APPEARS TO
BE STABILIZING A SIGNIFICANT PORTION OF CENTRAL AND EASTERN OKLAHOMA
INTO THE OZARKS.

...MIDDLE MISSISSIPPI/LOWER OHIO VALLEY...
A BELT OF MODEST WEST SOUTHWESTERLY LOWER/MID TROPOSPHERIC FLOW...ON
THE ORDER OF 30+ KT...ASSOCIATED WITH REMNANT CONVECTIVELY GENERATED
CYCLONIC VORTEXES...MAY ENHANCE THUNDERSTORM ACTIVITY DEVELOPING
ACROSS EAST CENTRAL MISSOURI INTO PARTS OF CENTRAL ILLINOIS AND
NORTHERN/CENTRAL INDIANA BY THIS AFTERNOON. DESTABILIZATION TO THE
SOUTH OF THE WEAK COLD FRONT...EXTENDING EAST NORTHEAST OF THE MID
MISSOURI VALLEY INTO THE LOWER GREAT LAKES...MAY BE LIMITED BY
RELATIVELY WEAK MID-LEVEL LAPSE RATES...PERHAPS WEAK SURFACE HEATING
AS WELL. BUT IT COULD BECOME SUFFICIENT TO SUPPORT A RISK FOR
SEVERE WIND GUSTS AND SOME HAIL IN STRONGER ACTIVITY...BEFORE
CONVECTION WEAKENS THIS EVENING.

..KERR/ROGERS.. 05/09/2013

[srainhoutx]

MESOSCALE DISCUSSION 0608
NWS STORM PREDICTION CENTER NORMAN OK
0639 AM CDT THU MAY 09 2013

AREAS AFFECTED...CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 091139Z - 091415Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...ISOLATED STRONG TO SEVERE STORMS CAPABLE OF LARGE HAIL
WILL BE POSSIBLE THROUGH THE MORNING HOURS. HOWEVER...ACTIVITY MAY
REMAIN TOO ISOLATED FOR A WATCH.

DISCUSSION...ISOLATED THUNDERSTORMS HAVE FORMED JUST E OF SJT NEAR
THE NOSE OF THE THETA-E AXIS. LATEST SURFACE ANALYSIS ALSO SHOWS AN
INCREASED SFC TEMPERATURE AND DEWPOINT AT SJT INDICATIVE OF SOME
VERTICAL MIXING AND PERHAPS EROSION OF CIN. ALSO AIDING IN LIFT IS A
LOW AMPLITUDE FEATURE ALOFT SEEN ON SATELLITE. THE STORMS ARE
FORMING IN AN ENVIRONMENT CHARACTERIZED BY STEEP LAPSE RATES ALOFT
BUT WITH A SOMEWHAT JUMBLED WIND PROFILE IN THE LOWER 4-5 KM AS SEEN
ON VWP. THIS IS CURRENTLY RESULTING IN A CLUSTER OF MULTICELLS.

MODEL CONSENSUS IS FOR THESE STORMS TO PERSIST AND/OR INCREASE IN
COVERAGE LATER THIS MORNING ACROSS CNTRL TX AS WARM ADVECTION
PERSISTS. THE STRONGER CORES MAY HAVE PERIODIC SEVERE HAIL. A WIND
THREAT APPEARS UNLIKELY AT THIS TIME...BUT COULD INCREASE LATER
TODAY IF THE CLUSTER MANAGES TO GET LARGE ENOUGH TO PRODUCE
SUBSTANTIAL OUTFLOW.

..JEWELL/KERR.. 05/09/2013


ATTN...WFO...FWD...SJT...

[srainhoutx]

Severe Thunderstorm Watch likely ahead for Central Texas:

MESOSCALE DISCUSSION 0609
NWS STORM PREDICTION CENTER NORMAN OK
0937 AM CDT THU MAY 09 2013

AREAS AFFECTED...PORTIONS OF CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 091437Z - 091630Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...STORM COVERAGE WILL LIKELY CONTINUE TO INCREASE THROUGH
THE REMAINDER OF THE MORNING. SOME OF THE MORE ROBUST UPDRAFTS WILL
ORGANIZE AND BE CAPABLE OF AT LEAST SOME LARGE HAIL THREAT.

DISCUSSION...RADAR MOSAIC OVER THE PAST HOUR HAS SHOWN AN UPTICK IN
STORM COVERAGE/INTENSITY OVER CNTRL TX. 12Z UPPER AIR ANALYSIS
SHOWS LOW LEVEL CONFLUENCE SEEMINGLY MAXIMIZED OVER THIS
REGION...AHEAD OF A MID LEVEL IMPULSE OVER SERN NM/NRN MEXICO.
DESPITE WIDESPREAD CLOUD COVER DELAYING SURFACE HEATING...INCREASING
LARGE SCALE FORCING FOR ASCENT WILL LIKELY SUPPORT CONTINUED STORM
DEVELOPMENT.

THE 12Z DRT RAOB SHOWS A RATHER MOIST BOUNDARY LAYER --15 G/KG MEAN
MIXING RATIO-- WITH VERY STEEP LAPSE RATES ALOFT /9 DEG C/KM H7-H5
LAYER/. STRONG DIFFLUENT UPPER LEVEL FLOW WILL ACT TO ORGANIZE
STORMS WITH TIME AND SUPPORT AN INITIAL LARGE HAIL THREAT WITH THE
STRONGER STORMS.

..SMITH/CORFIDI.. 05/09/2013


ATTN...WFO...FWD...EWX...SJT...

[srainhoutx]

E-mail from Jeff:

Very active 48-72 hours expected across the state as a slow moving upper level low and cool front combine with increasing Gulf and Pacific moisture.

Upper level storm system over the SW US has stalled out this morning with a strong connection of sub-tropical moisture plume from the central Pacific NE across MX into C TX on the south and east flank of this system. A weak cool front is over NW TX and just ahead of this feature severe thunderstorms have developed in the last hour near Brownwood, TX. Pattern over the next few days will be highly meso scale driven with multiple storm complexes moving across the region while the upper level pattern remains nearly unchanged. With the upper level storm remaining to our west broad upper air divergence will be maintained for the next 72 hours helping to vent surface convection. Frontal boundary will only slowly move toward the coast under the help of outflow boundaries and should limp to the coast by early Sunday.

Main concerns are timing of storms, rainfall amounts, and the severe weather threat.

Timing:
Appears in water vapor images that a disturbance is crossing the Rio Grande currently and should progress eastward this afternoon. Short term models blow up convection over C TX and our NW counties this afternoon into the evening hours and progress it E into E TX as a linear line or MCS. I am wary of the southward trailing outflow boundary however which appears to reach toward I-10 this evening and overnight as this could support additional slow moving storm development further south. Question appears to be with the intensity of the capping along and south of I-10 and at this time it appears that the capping will hold convection over these areas in check this evening.

Numerous boundaries will likely be in place early Friday and once heating onsets, expect thunderstorms to once again fire off with the approaching frontal zone and additional disturbances out of MX. Hard to exactly pin down the best time or location for development, but will aim for the central counties roughly from Columbus to Conroe during the afternoon hours with storms then drifting into the metro area and southern area in the evening hours.

Saturday is even more of a wild card as the air mass begins to become worked over and boundaries near the coast. Could see heavy rains and storms focus near the coast or offshore although several models develop more convection near the lagging 850mb front further inland. A lot is going to happen between now and Saturday and the forecast for Saturday is highly dependent on the next 24-48 hours of weather.

Heavy Rainfall:
Moisture levels are on the increase this morning with 1.4 inch PWS over the NW Gulf moving onshore. Mid and high level moisture is also noted over MX streaming toward TX. PWS are forecast to increase into the 1.5-1.6 range on Friday which is in the 75-90 percentile for early May. Potential for slow moving and training storms along boundaries will be increasing as there will be little movement of the main upper trough and good upper level divergence over the next 72 hours. Storms will focus on the boundaries. Feel the models are likely not handling he meso scale situation overly well nor the placement of activity as this is nearly impossible to predict more than a few hours out in time. Given moisture levels, excessive rainfall rates will become increasingly likely under the stronger storms with rates approaching 2.0 inches per hour possible. Widespread amounts of 1-3 inches appear likely between this afternoon and early Sunday with isolated amounts of 4-5 inches. Some flooding is possible with this type of pattern.

Severe Weather:
Recent short term models have suggested an increase in the severe threat for a larger part of SE TX this afternoon. Some of this is currently being driven by the formation of severe storms over W/C TX currently. Cloud cover over the region should keep instability on the lower side today along with the mid-level warm nose however should storms to our NW form into an MCS a threat for strong winds would be possible this afternoon north of I-10. Severe threat on Friday is conditional on the events today and tonight. Little change in the air mass would seem to support a risk of additional severe storms with hail and wind being the main threats. However, if an outflow boundary undercuts the unstable surface layer this could mitigate some of the severe weather threat on Friday. Once again I stress that meso scale influence will play a big role in developments over the next 1-3 days.

SPC Outlooks for Today and Friday:

Today:

The attachment 05092013 SPC day1otlk_1300.gif is no longer available

Friday:

[/i]

[srainhoutx]

[wxman57]

Can someone get the Aggies to do a mid day balloon release, since, as always, capping appears to be an issue.

OK. Our friends at College Station did an 18Z balloon launch:

[wxman57]

It's a pretty good "warm nose" up in CLL. Could be greater down here in Houston.

[redneckweather]

Yep, I don't see much today for our central/southern tier of counties and perhaps even our northern viewing area.

[srainhoutx]

MESOSCALE DISCUSSION 0610
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT THU MAY 09 2013

AREAS AFFECTED...PORTIONS OF ERN AND SERN TX

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 091952Z - 092045Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...A NEW SEVERE THUNDERSTORMS WATCH WILL LIKELY BE NEEDED
DOWNSTREAM FROM THE ONGOING CNTRL TX MCS AS IT MOVES INTO ERN AND
SERN TX. ISOLD LARGE HAIL AND PERHAPS A CONFINED CORRIDOR OF DMGG
WINDS WILL BE THE MAIN THREATS WITH THIS ACTIVITY LATE THIS
AFTERNOON INTO THE EVENING HOURS.

DISCUSSION...RADAR MOSAIC SHOWS A STRONG TO LOCALLY SEVERE STORM
COMPLEX MOVING EWD AND IMPACTING THE CNTRL TX I-35 CORRIDOR. THIS
CONGLOMERATION OF STORMS WILL LIKELY CONTINUE TO GROW UPSCALE OVER
THE NEXT SEVERAL HOURS --PERHAPS ACCELERATING IN FORWARD MOTION-- AS
IT CONTINUES TO ENCOUNTER A STRONGLY UNSTABLE AIRMASS DOWNSTREAM
OVER ERN-SERN TX AND EVENTUALLY INTO SWRN LA.

THIS CONVECTIVE SYSTEM WILL CONTINUE TO ORGANIZE AS SSWLY 40-50 KT
1-2 KM AGL FLOW MAINTAINS A FETCH OF RICH BOUNDARY LAYER MOISTURE
UNDERNEATH A STOUT EML THAT WAS SAMPLED BY THE 18Z CLL SPECIAL RAOB
FROM TEXAS A&M. A GRADUAL TRANSITION FROM A LARGE HAIL/ISOLD DMGG
WIND THREAT IS FORECAST TO EVOLVE INTO MAINLY A DMGG WIND THREAT AS
THE MCS FORWARD PROPAGATES TOWARDS THE SABINE RIVER VALLEY THIS
EVENING.

..SMITH/CORFIDI.. 05/09/2013


ATTN...WFO...LCH...SHV...HGX...FWD...

[Kludge]

It's a pretty good "warm nose" up in CLL. Could be greater down here in Houston.

Well unless something changes in the next few minutes, College Station is gonna take a real hard punch in that nose.

Death to the Death Cap!!!

[wxman57]

Watch has been issued.

[MontgomeryCoWx]

Looks like I'm going to take it right on the chin.... yay!

I'm in north central Montgomery County.