Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 4

[Srain]

Not much in the way of cloud cover up here in NW Harris County this morning. The 06Z WRF/NMM is suggesting a short wave disturbance for the afternoon hours across the northern areas as that systems passes. The 00Z Euro is much more aggressive regarding rain chance on Friday for inland areas and the long range WRF is picking up on storms crossing the area in the longer ranges of that model. We'll see what the afternoon bring with the MCS currently over W Central Texas and if we can squeeze out some showers/storms before the frontal boundary drops any further S. The potent upper low is still to our W in the Baja Region and those disturbances offer a forecasting challenges at best as we saw many times this past winter and early spring.

From NESDIS:

SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 05/08/12 1136Z

SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-763-8678

LATEST DATA USED: GOES-13 1115Z GOES-15 1111Z CW

.

LOCATION...TEXAS...

.

ATTN WFOS...FWD...CRP...EWX...SJT...MAF...

ATTN RFCS...WGRFC...

.

EVENT...HEAVY RAINS

.

SATELLITE ANALYSIS AND TRENDS...CONVECTION CONTINUES TO DEVELOP/EXPAND

ACROSS PORTIONS OF SOUTHWEST TX THIS MORNING IN RESPONSE TO POTENT

SUBTROPICAL UPPER-LEVEL JET STRETCHED ACROSS NRN MEXICO...MAIN CONCERN

IS FOR LOCALIZED AREAS OF PERSISTENT HEAVY RAINS DUE TO CELL TRAINING

AND UPSTREAM CELL REDEVELOPMENT. VWPS OVER THE PAST SEVERAL HRS ACROSS

MUCH OF TX HAVE BEEN NERLY WHICH HAS ALLOWED GOOD LLVL MOISURE TRANSPORT

OF GULF MOISTURE TO BUILD UP ACROSS SW TX FOR CONVECTION TO FEED OFF OF.

ADDITIONALLY...GOES-IR AND PW SOUNDER PRODUCT SATELLITE LOOPS OVER THE

PAST FEW HRS INDICATES DECENT SERLY LLVL MOISTURE TRANSPORT FROM GULF

OF MEXICO. THIS SECOND AND MORE DIRECT TRANSPORT OF GULF MOISTURE ACROSS

DEEP SOUTH TX LIKELY WILL HELP AID ANY STORMS THAT DEVELOPS ALONG THE

SRN EDGE OF THE AREA OF CONVECTION ACROSS SW TX.

WITH BEST MOISTURE TRANSPORT SETUP ALONG THE SRN EDGE OF ONGOING AREA OF

CONVECTION...IT IS THIS AREA THAT IS OF MOST CONCERN FOR CELL TRAINING

AND HEAVIEST RAINFALL OVER THE NEXT 3-6 HRS. WITH THIS IN MIND...GOES-W

WATER VAPOR LOOP ALONG WITH SATELLITE DERIVED UPPER-LEVEL WINDS SEEM TO

INDICATE TROUGH LOCATED FROM SRN CA/SRN AZ TO JUST OFFSHORE OF BAJA CA

IS STILL IN THE PROCESS OF DIGGING. AS A RESULT...TROUGH IS EXPECTED TO

SINK FURTHER SOUTH THUS FORCING SUBTROPICAL JET TO ALSO TREND FURTHER S.

AREA OF BEST UPPER-LEVEL DIFFLUENCE FROM JET EXIT REGION LIKELY TO SETUP

CLOSER TO 30N 100W. THIS WOULD ALL SEEM TO INDICATE THAT CONVECTION

LIKELY TO SLIDE SWD DURING THE MORNING/EARLY AFTERNOON AND HEAVIEST

RAINS WOULD BE ALONG THE S SIDE...WHERE MOISTURE TRANSPORT IS GREATEST.

.

AN ANNOTATED SATELLITE GRAPHIC SHOWING THE HEAVY PRECIPITATION THREAT AREA

SHOULD BE AVAILABLE ON THE INTERNET ADDRESS LISTED BELOW IN APPROXIMATELY

10-15 MINUTES.

.

SHORT TERM OUTLOOK VALID 1130-1530Z...MEDIUM CONFIDENCE FACTOR IN SHORT

TERM OUTLOOK...CONVECTION ACROSS SW TX EXPECTED TO CONTINUE TO THRIVE

THROUGH THE MORNING HRS ACROSS SW TX AND HEAVY RAINS ARE LIKELY GIVEN WELL

ABOVE AVG LLVL MOISTURE AND STRONG UL DYNAMIC FORCING FROM SUBTROPICAL

JET STRETCHED ACROSS NRN MEXICO. PRESENCE OF MODEST NERLY FLOW SHOULD AID

IN THE SLOW MOVING NATURE OF CONVECTION AND BACK-BUILDING OF CELLS FOR

LOCALIZE CELL TRAINING. GREATEST THREAT OF HEAVY RAIN POTENTIAL LIKELY

TO BE ALONG THE SRN EDGE OF CONVECTION AREA AND THIS IS ANTICIPATED TO

SLOWLY SLIDE SWD OVER THE NEXT SEVERAL HRS TOWARD BETTER LVLL MOISTURE

CONVERGENCE DUE TO NOSE OF SUBTROPICAL JET DROPPING SWD AS TROUGH OVER

ERN PACIFIC INTENSIFIES.

[DoctorMu]

Now we're talkin. Yesterday may have primed the pump for some big action early this afternoon. CLL had 0.79 in last evening as the trough held together. Come to papa!

Another SW on the way and then an ULL should eject and ride the train this way. All aboard!

[Ed Lizard]

I don't know if current light North winds are the result of the actual front or rain cooled outflow in SETX, but with DPs still in the 60s and full May insolation, I am glass half full on some fun-derstorms today. SPC/RAP analyzed CAPE is pretty unimpressive now, but winds going East should keep the DPs from falling anymore, we should warm nicely, we have a not impressive but maybe just good enough ~30 knots of 0-6km shear, and who knows what kind of boundaries around for some low level lagniappe, glass half full, I say. Speaking of boundaries, light winds, Gulf offshore upper 70s, full Sun, not warm enough to develop a seabreeze yet, but again, full Sun for now...

Visible loop of happiness.

[Srain]

MESOSCALE DISCUSSION 0757

NWS STORM PREDICTION CENTER NORMAN OK

1044 AM CDT TUE MAY 08 2012

AREAS AFFECTED...DEEP SOUTH TEXAS

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 081544Z - 081645Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...SHORT TERM CONVECTIVE TRENDS REMAIN UNCERTAIN...BUT

CURRENT INTENSIFICATION OF A STORM TO THE SOUTH OF LAREDO MAY

REQUIRE A WATCH SHORTLY.

DISCUSSION...WITHIN AN AREA LARGE-SCALE ASCENT DOWNSTREAM OF THE

SOUTHWESTERN U.S. CLOSED LOW AND UPPER TROUGH EXTENDING SOUTHWARD

THROUGH BAJA...SCATTERED THUNDERSTORM ACTIVITY CONTINUES TO

GRADUALLY SPREAD EASTWARD THROUGH THE LOWER RIO GRANDE VALLEY TOWARD

LOWER TEXAS COASTAL AREAS. ACTIVITY EAST OF THE RIVER HAS BEEN

GENERALLY CONFINED TO THE COOL SIDE OF A SOUTHWARD ADVANCING COLD

FRONT...WITH RESIDUAL WARMER ELEVATED MIXED LAYER AIR STILL

INHIBITIVE OF BOUNDARY LAYER BASED STORM DEVELOPMENT TO THE SOUTH.

ADDITIONALLY...LATEST RAPID REFRESH IS SUGGESTIVE THAT LOWER/MID

TROPOSPHERIC WARM ADVECTION MAY WEAKEN ACROSS THE REGION DURING THE

17-19Z...WHICH COULD RESULT IN DIMINISHING CONVECTIVE TRENDS.

SO...NEAR TERM SEVERE WEATHER POTENTIAL REMAINS UNCLEAR.

HOWEVER...RECENT INTENSIFICATION OF A CELL IS UNDERWAY OFF THE

HIGHER TERRAIN TO THE SOUTHWEST OF LAREDO. THIS APPEARS TO THE

SOUTH OF THE FRONT...AND WEAK WESTERLY DEEP LAYER MEAN FLOW COULD

AID PROPAGATION INTO A DESTABILIZING ENVIRONMENT EAST OF THE

RIVER...WHERE ADDITIONAL SURFACE HEATING COULD CONTRIBUTE TO

WEAKENING OF INHIBITION AND FURTHER INTENSIFICATION.

..KERR.. 05/08/2012

ATTN...WFO...CRP...EWX...BRO...

[Ed Lizard]

Now that we're in mid 80s, does HOU area have an uncapped LCH 7 am sounding or a still capped CRP 7 am sounding?

[DoctorMu]

Meaty Beaty Big and Bouncy

http://radar.weather.gov/radar.php?rid=GRK&product=NCR&overlay=11101111&loop=yes

[Srain]

We need the rain. As Jorge commented, the pattern looks like last winter...

[Srain]

Morning e-mail from Jeff:

Meso scale features playing havoc with forecast. Strong storm system will move into the area Thursday night-Saturday with heavy rainfall and severe weather possible.

Weak cool front slipped through the area late yesterday afternoon which helped to usher in a drier air mass from the north and kept all of the thunderstorms activity on Tuesday confined to our SW and right along the coastal seabreeze front. Air mass has continued to slowly dry overnight with dewpoints now into the low to mid 60’s areawide. Weak short wave over central TX is producing a small area of rain showers east of Austin and SW of College Station currently with a movement toward the east, this feature will be over SE TX today. Not overly impressed with rain chances for today and feel the current cloudy conditions will limit heating along with weak northerly flow will keep instability on the low side. Also there is no real good focus for surface convergence with the front now south of the area. Will go with 20-30% for a few showers as the central TX disturbance moves across.

Air mass dries even more tonight with weak ridging developing over the region for Thursday ahead of the strong closed Baja low. As this low begins to eject eastward early Thursday downstream height falls will result in low pressure forming over the Rio Grande plains which will in turn start to pull the frontal boundary northward as southerly flow develops. Moisture will rapidly increase over S TX Thursday with PWs climbing to near 2.0 inches by Thursday evening. Strong heating and moisture influx, combined with a strong short wave rotating around the east side of the upper low into NE MX along with increasing strong upper level divergence all point to rapid and strong thunderstorm formation over NE MX and the Rio Grande plains Thursday afternoon. Storms should quickly grow upscale with favorable 40-50kts of SW shear into a large thunderstorm complex (MCS) across SC TX Thursday evening. Severe weather appears at least possible with this feature as downstream instability over the coastal bend and influx of rich Gulf air mass will be in place. MCS should move E to ESE overnight Thursday into Friday morning and will likely approach/move into our W/SW counties before sunrise. Not sure how far east this complex will make it as this depends greatly on how quickly the air mass over SE TX moistens on Thursday night and how fast the offshore frontal boundary lifts northward. It is very possible that this complex feeds ESE or even SE offshore along the frontal boundary and into the NW Gulf keeping all the moisture offshore….this has been hinted at over the past few model runs with the highest QPF offshore. However we are dealing with the meso scale and little is certain this far out…but there is a fair amount of uncertainty in the Friday-Saturday forecast.

At some point we should see some decent thunderstorm coverage as the main upper air system moves across the state Friday-Saturday, but as mentioned above the meso scale with its large thunderstorm complexes may throw a wrench in that thinking. Will really have to wait to see how things play out Thursday night/Friday morning before becoming more confident in additional rains Friday afternoon. With a slightly slower movement of the main upper level storm…rain chances will likely need to be carried over into Saturday at least through the morning hours.

[Srain]

Sweet...

[Srain]

Morning e-mail from Jeff:

***Heavy rainfall and severe weather possible this afternoon-Friday night***

Impressive upper level storm system over northern MX has begun its assault on the state of TX this morning. Radar already show widespread deep convection developing over SW/W TX on the leading edge of lift on the eastern flank of the storm system and returning SE flow off the Gulf of Mexico. At the surface a weak frontal boundary remains stalled along the lower to middle TX coast then ENE toward the central Gulf coast. Strong upper level forcing spreading eastward out of MX today will help develop a frontal wave over southern TX today with a warm front backing northward and likely inland across SE TX tonight. Short term models indicate that thunderstorm formation is at least possible today as the boundary returns northward over the area and/or SW TX storms move into the region from the WSW by mid afternoon. Still a decent amount of dry air at the surface over this area compared to areas to our SW so once again as seen on Tuesday what looks impressive to our west may weaken as it approaches…with that said, the current air mass will be undergoing fairly rapid modification today.

Main event looks on tap for tonight as either one or more convective complexes develop over NE MX/SW TX and race eastward toward the area. Strong upper level divergence on the eastern flank of the upper level system combined with 40-55kt of shear, good SE low level flow, and high moisture levels (PWS nearing 1.7-1.9 inches) all support vigorous thunderstorm formation. Uniform shear inland suggest scattered thunderstorms will grow rapidly upscale into a large MCS feature and progress E/ESE toward the TX coast…this is supported by the TX Tech meso WRF model showing a large MCS plowing across much of the area between midnight and 800am Friday. This model is showing a fairly strong “bowing” signal and with favorable wind energy in the mid levels, wind damage looks possible along the leading edge of this line.

Meso scale processes will drive the weather post 600am Friday as the potential for a large thunderstorm complex to be ongoing over the region at that time. Models time to re-develop convection behind the initial complex, but this is highly uncertain as the air mass will likely be heavily worked over and stabilized. However the slow moving upper level system will still be located NW of the region placing the area under favorable dynamics aloft so it will not take much to get things going.

Severe Threat:

Biggest uncertainty is how quickly and far north the offshore surface boundary moves determining how far inland a juicy air mass penetrates. Models have been wanting to hold this feature near the coast and even offshore, but recent guidance has trended more northward with the track of the main upper level storm which will likely help pull the boundary further inland across more of SE TX. Another concern is the potential for convection this afternoon either developing on the boundary or approaching from the west to help push the boundary back southward due to cool storm outflows. Feel the boundary will push inland later today and possible reach I-10 tonight. SPC has our SW counties outlooked for severe weather tonight and it is very possible that this area will need to be expanded to include more of the region. My current thinking is area SW of a line from College Station to The Woodlands to High Island will have some degree of severe threat tonight. Wind damage is likely the main severe mode with any type of linear/bowing thunderstorm complex although low level shear will be enhanced near the frontal boundary across the region. Feel any threat of supercells and tornadoes will be greatest this afternoon and evening south of Matagorda Bay over S TX where low level shear is strongest and instability is greatest.

Heavy Rainfall:

Widespread rainfall of 1-3 inches appears likely which most areas will be able to handle without major problems. Concern comes with the potential for any additional develop on Friday behind the main line or the possibility that the complex of storms slows as it nears the coast and stalls. Moisture levels will be extremely high and the upper levels will have good venting along with a vigorous feed of deep moisture off the Gulf. This all supports high hourly rainfall rates in the stronger storms with potential for a few 2-3 inch amounts in an hour or less. Urban areas may have some issues with that kind of rainfall rate. Flash Flood Guidance is fairly high over the region given the recent dry spell and current QPF forecast are not exceeding those values, so the NWS has decided to hold off on a Flash Flood Watch for now. Trends today may require a watch be issued later today or this evening.

Day 1 (Today) Severe Weather Outlook:

[Srain]

Update from Jeff:

Large slow moving upper level storm system to bring several rounds of heavy rainfall to Harris County.

Thunderstorms have already developed out west of the area this morning and are moving toward the county. Forecast models are in decent agreement on a round of storms late this afternoon followed by another round early Friday morning. A fairly dry air mass in place currently will rapidly moisten today with moisture levels increasing to nearly 200% of normal by late tonight. A large thunderstorm complex will develop over SC TX this afternoon and move across the region early Friday with a slowing forward motion.

Excessive hourly rainfall rates of 2-3 inches will be possible with this line of thunderstorms. While grounds are dry from the recent dry spell, very high moisture levels, potential slow storm motions, and the slow motion of the main upper level storm all point to a threat for an extended period of potential heavy rains from late this afternoon through Saturday midday. Small scale features that global forecast models cannot resolve will likely determine where the heaviest rains will fall…current thinking via model guidance and WGRFC forecasters in near or south of I-10. Widespread 1-3 inches is likely with isolated amounts of 3-5 inches possible.

Rainfall of this magnitude even on dry grounds will result in significant run-off especially over urban areas. Ponding and flooding of low lying areas and areas of poor drainage will be possible. NWS may issue a Flash Flood Watch later today based on radar and model trends.

[My Weather Today]

FLASH FLOOD STATEMENT

NATIONAL WEATHER SERVICE CORPUS CHRISTI TX

1103 AM CDT THU MAY 10 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1230 PM CDT FOR

NORTHWESTERN LA SALLE COUNTY...

...A FLASH FLOOD EMERGENCY IS NOW IN EFFECT FOR NORTHWESTERN LA

SALLE COUNTY...

AT 1059 AM CDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED FLASH

FLOODING OVER THE WARNED AREA. HIGHWAY FM 468 8 MILES NORTHWEST OF

COTULLA IS NOW CLOSED DUE TO HIGH WATER. THE WATER IS 2 FEET OVER

THIS ROAD AND RISING. DOPPLER RADAR ESTIMATED MORE THAN 6 INCHES OF

RAIN HAS FALLEN ACROSS MUCH OF THE WARNED AREA. WITH MORE RAIN

MOVING IN FROM THE SOUTHWEST...AN ADDITIONAL 2 TO 4 INCHES OF RAIN

WILL BE POSSIBLE ACROSS COMMUNITIES SUCH AS MILLET.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO MILLET

AND WOODWARD. SOME CREEKS THAT WILL EXPERIENCE FLOODING

INCLUDE...ESPIO...SALT AND CIBOLO.

[Srain]

Update from Jeff:

Tornado Watch has been issued until 800pm for all of S TX and the coastal bend.

Discussion:

Strong lift with impressive upper level storm over NE MX this morning is overspreading S TX and the Rio Grande plains currently. Recent storms south of San Antonio and WSW of Corpus have grown into tornado producing supercells as the air mass has destabilized due to surface heating and influx of rich Gulf moisture. Strong jet streak on the southern flank of the upper system over NE MX is translating eastward into SC/S TX currently with increasing shearing being produced as surface winds remain backed to the south and near the returning frontal boundary. Additional heating and stronger forcing arriving in the next few hours will continue to support supercell formation with tornadoes, very large hail and wind damage all threats.

Good potential for supercells to congeal into a large MCS late this afternoon and approach the region overnight. Potential appears to be increasing for widespread corridors of wind damage overnight as this storm complex moves to the TX coastal plain. As suspected this morning, SPC has pushed the slight risk region to include the SW ½ of SE TX for tonight and some additional expansion to the NE may be required.

Main threats this afternoon will be supercells with very large hail and possible tornadoes mainly WSW and SW of our area and then the threat will transition into a damaging wind threat overnight as the complex moves into and across SE TX. Damaging winds on the leading edge of the complex are possible as strong mid level energy is brought to the surface and possible meso low formation bow out the leading edge of the line are various locations and times. Isolated short lived tornadoes will also be possible along the leading edge of the line especially near any couplet segments. Additional weather watches are likely into the overnight hours.

[DoctorMu]

Long-train runnin' is comin' through the CLL station

[Srain]

BULLETIN - EAS ACTIVATION REQUESTED

FLASH FLOOD WARNING

NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX

802 PM CDT THU MAY 10 2012

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* FLASH FLOOD WARNING FOR...

HAYS COUNTY...

TRAVIS COUNTY...

WILLIAMSON COUNTY...

* UNTIL 1000 PM CDT.

* AT 800 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE

DETERMINED THAT RAINFALL ESTIMATES FROM DOPPLER RADAR INDICATE A

LINE OF THUNDERSTORMS WITH VERY HEAVY RAINFALL APPROACHING

THE AUSTIN METRO AREA FROM THE WEST. RAINFALL AMOUNTS OF BETWEEN

ONE AND TWO INCHES WILL OCCUR IN ONE HOUR OR LESS.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO

OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...

ANDERSON MILL...AUSTIN...AUSTIN BERGSTROM INT AP...CEDAR PARK...

DRIPPING SPRINGS...GEORGETOWN...PFLUGERVILLE...ROUND ROCK...

SERENADA...TANGLEWOOD FOREST...TAYLOR...WIMBERLEY...WINDEMERE...

ANDICE...BEE CAVE...BUDA...COUPLAND...DRIFTWOOD...GEORGETOWN DAM...

HUTTO...KYLE...LAGO VISTA...LAKEWAY...LEANDER...LIBERTY HILL...

MANOR...MANSFIELD DAM...MUSTANG RIDGE...ONION CREEK AND

ROLLINGWOOD.

[DoctorMu]

Wheel in the Sky keeps on Turnin'

We could be all swimming tomorrowwwowoah...

http://www.goes.noaa...LOOPS/ecwv.html

major bow echo near Pflugerville. Could be some rotation in cells on this side of the ULL. Damaging winds at the least

http://radar.weather.gov/radar.php?rid=ewx

[Srain]

Morning e-mail from Jeff:

Large thunderstorm complex moved across mainly he southern part of the area overnight and is now located over the central LA coast WSW to off the coast of Brownsville.

Severe weather really hammered areas of SC, S TX into the coastal bend yesterday afternoon and overnight with many reports of wind damage. Large upper low nearly stationary of moving very slowly NE over NW TX this morning with skies clearing over SE TX from the west behind the overnight storms. Air mass has been strongly overturned overnight with low level moisture depleted as shown by dew points in the low 60’s. However with the upper level system still west of the area and favorable dynamics aloft along with clearing skies resulting in surface heating the air mass will begin to recover early this afternoon. Impulse on the southern flank of the upper low is move eastward across central TX and this combined with heating may result in additional storm development by mid to late afternoon. Not overly confident is where/when storms will develop if at all given subsidence on the backside of the NW Gulf complex and depleted instability over the region.

Should storms develop a few may become strong to severe with large hail and damaging winds the main threats.

Upper low will slowly progress out of TX on Saturday taking lingering rain chances with it. Will need to watch potential for additional energy to drop Se in the mean flow and attempt to carve out another trough over the region in the Mon-Wed period, but it is uncertain how much moisture will be available to support any thunderstorm chances.

Will try and get a detailed storm report out today from overnight events.

[Srain]

RECORD EVENT REPORT

NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX

455 AM CDT FRI MAY 11 2012

...NEW RECORD FOR GREATEST DAILY RAINFALL AT HOBBY AIRPORT TODAY...

HOBBY AIRPORT RECEIVED A HEAVY RAINFALL OF 2.54 INCHES EARLY THIS

MORNING BETWEEN MIDNIGHT AND 6 AM. THIS SETS A NEW RECORD FOR THE

GREATEST RAINFALL FOR THIS DATE. THE PREVIOUS RECORD RAINFALL WAS

1.94 INCHES IN 2004. THIS AMOUNT MAY INCREASE LATER TODAY DUE TO

ANY ADDITIONAL RAINFALL.

[Ed Lizard]

Some rotation on cell stradlding Southern Harris County border.

http://radar.weather.gov/radar.php?rid=hgx&overlays=11101111&product=N0S&loop=yes

Anyhow, my yard did better this evening than either DWH or IAH, the two nearest obs points. I don't have a gauge but it must be near half an inch by eyeball guesstimate.

[Srain]

Some locations S of I-10 are nearing 10 inches of rainfall over night and lots of flooding with water in homes in Ft Bend, Southern Harris & Galveston Counties. Storms cointinue to fire all the way back to S Texas in a broken line that becomes more concentrated SW of Houston through our Metro Area and on E into the Beaumont Area.

[Srain]

E-mail from Jeff:

Very impressive local scale flash flood event over Fort Bend and southern Harris County overnight.

Radar and now ground truth reports show amounts of 8-11 inches over central Fort Bend County from north of Beasley to Sugar Land. Amounts of 4-7 inches fell over southern Harris County from Friendswood to Missouri City. The result has been extensive and widespread flooding over much of Fort Bend and southern/southwest Harris Counties.

Rainfall/Flooding Reports:

Richmond, Fort Bend: 10.70 inches of rainfall recorded by public CoCoRahs site (nearly the entire 11 inch gage was full)

Sugar Land, Fort Bend: 8.25 inches recorded by Hull Field ASOS station between 1-7am. Runways flooded, numerous subdivisions with extensive knee to waist deep flooding.

Sugar Land, Fort Bend: 7.42 and 7.58 inches of rainfall reported via public CoCoRahs stations in Greatwood subdivision

Richmond, Fort Bend: 4.06 inches recorded by public CoCoRahs station in Bonbrook subdivision.

Westbury, Harris: 6.49 inches recorded by public CoCORahs station

Pecan Grove, Fort Bend: 9.74 inches of rainfall recorded from home weather station. Nearly every street flooded, some cars underwater. Subdivision was cut off due to overflowing creeks

Richmond, Fort Bend: numerous roads impassable throughout the city with various high water rescues.

Sugar Land, Fort Bend: Intersection of US 99 and HWY 90 under 6-15 feet of water and closed in all directions. US 99 impassable at several locations north of HWY 90.

Richmond, Fort Bend: 8.93 inches measured by public in the Windloch subdivision

League City, Galveston: 5.57 inches recorded by public CoCoRahs station

Friendswood, Galveston: 6.13 inches recorded by public CoCoRahs station.

Radar Rainfall Estimate

[Ed Lizard]

Back to dullsville in SETX. I am hoping for a couple of tenths on Tuesday, reducing need to water the new Bermuda.

[Srain]

Morning e-mail from Jeff:

After the big rains a week ago the weather has been quite across the region.

Combination of slightly increased moisture and a SW sagging boundary along with a short wave advancing across NE TX in the NW flow aloft may support a round of late afternoon and evening thunderstorms across mainly the northern and eastern sections of SE TX today. Pattern set up is more favorable of July than mid May with ridging out west of the region placing SE TX in a NNW flow aloft this morning. While the air mass aloft is fairly dry, there appears to be enough moisture to provide at least a chance of thunderstorms this afternoon/evening as shown by several of the high resolution meso models. Storms that develop will likely produce good outflow winds with the dry mid level air which will in turn help push activity deeper into the region. Additionally the local seabreeze will be advancing inland and could possibly meet with incoming outflow boundaries from the NNE to help produce more thunderstorms near/south of I-10. Some threat of some really gusty winds given the mid level dry layer and brief heavy rainfall.

May see additional slim chances for storms Tuesday and Wednesday afternoons along the seabreeze boundary as it makes its daily push inland.

Toward the end of the week into next weekend, the ridge aloft over the state will begin to break down as a strong trough advances into the western US. This will help create a weakness in the height field over TX and a plume of tropical moisture looks to advect into the region from the Gulf supporting afternoon shower and thunderstorm development along possibly an active seabreeze if the pressure gradient is not too strong over the region.

Other item to watch will be current TD # 2 in the eastern Pacific as global and hurricane forecasting models are taking this system NW then N into the SW Mexican coast by the end of the week as the system is captured by the trough digging into the western US. This is a fairly large tropical cyclone and its moisture evelope will be larger than average. The current track is not a classic track for significant moisture advection into TX as I would like to see the system impact more northward along the Mexican coast to ensure better transport toward TX, however with the trough advancing in from the west near the same time it is still possible for some of this deep mid and high level moisture to be brought northward over at least eastern TX by the end of next weekend….and this could enhance rainfall over the area. Still lots of time to watch and fine tune especially since the latest guidance tracks have shifted westward and now NHC lies near the eastern edge of the guidance cluster.

NHC Forecast Track with Error Cone:

[wxmx]

Ouch!

METAR MMAN 241940Z 12005KT 10SM SCT080 45/13 A2961 RMK 8/070 HZY

There's still 1 hour window to break the all time record at this station (I'm not sure of the exact figure, but it's around 45-46C)

[DoctorMu]

Ouch!

There's still 1 hour window to break the all time record at this station (I'm not sure of the exact figure, but it's around 45-46C)

Yep, it's 113°F or 45° egg-frying weather there. Not much relief there and in Texas until perhaps the 1st or 2nd of June. No real fantasy GFS stuff until the 8th.

TG we saw a few of those paroxysmal ULLs this year. It's looking and feeling like mid and upper cap drought-like weather...

[Srain]

Morning e-mail from Jeff:

Chances for needed rainfall may return to the area by Thursday.

Dry pattern upper level pattern of ridging aloft and at the surface continues to support little if any rainfall over the area…as has been the case for the past 1.5-2 weeks. Ground moisture is starting to dry with the hot afternoon temperatures and gusty south winds. Ridging aloft will break down slightly by Thursday as a trough ejects into the upper Midwest allowing a late season cold front to move into the region. Forecast models are in decent agreement on this boundary moving through SE TX late Thursday into early Friday. Air mass over the area will become strongly unstable by Thursday afternoon with CAPE values of 3000-4000 J/kg as surface temperatures warm into the lower 90’s. Question is to what degree does the capping in the mid levels weaken as ridging aloft extending northward from MX and the Gulf must relax some allowing the mid levels to cool. Suspect the ridging aloft will weaken enough especially north of I-10 to allow storms to develop along the SE moving cold front during peaking heating Thursday afternoon. SPC has a large portion of the area outlooked for severe weather on Thursday, but feel the greatest threats will be north of I-10. Still time to watch and get the details nailed down, but some area will hopefully see some needed rainfall especially north of I-10 and east of I-45 where current KBDI values are pushing into the 500-600 range indicating that vegetation health is starting to suffer due to lack of ground moisture….we do not want to get back into a pattern anywhere close to last summer!

Front looks like it will actually push off the coast allowing drier air to filter into the region with lows falling into the lower to mid 60’s for Saturday morning…very nice for early June. Front washes out and moisture returns by late in the weekend into early next week. With surface winds on the lower side compared to late, and ridging aloft not forecast to be as strong, the seabreeze front may be able to spark a few isolated to scattered storms by early next week as we settle into a more typical summer pattern along the NW Gulf coast.

Tropical:

Tropical Storm Beryl (the second of the Atlantic Basin season formed off the coast of NC Friday evening and moved SW around a ridge of high pressure centered over the OH valley to a late Sunday evening landfall over northeast FL. Beryl made a direct hit on the Jacksonville metro area with sustained winds of an impressive 70mph for a late May tropical cyclone. The Jacksonville radar clearly showed the system tightening just prior to landfall with a big band of heavy convection wrapping around the western side of the broad center…this is likely what helped transport a lot of wind energy aloft to the surface with a gust of 73mph recorded at Buck Island and numerous gust of 50-65mph across NE Fl and SE GA.

A few storm reports from Beryl landfall:

Midway , FL: 12.65 inches of rainfall

Daytona Beach, FL: 1 fatal, 19-yr old male carried 10 miles by wave action and rip currents

Haulover Canal: USAF wind tower # 421 measured 44mph wind gust

Patrick AFB: 48mph wind gust

Kennedy Space Center: USAF wind tower # 110 recorded 54mph wind gust

Playalinda Beach: 59mph

Ocala: 57mph

Harrietts Bluff, FL: Estimated winds to 65mph, pine trees downed

Jacksonville Beach, FL: storm surge and wave action rose to beach dune bases, wind gust to 56mph

Jacksonville Naval Air Station: 65mph wind gust

Buoy 6 miles E of Fernandina Beach: 15 foot seas

Fernandina Beach: storm surge of 3.47 feet.

Mayport, FL: sustained winds of 54mph gust to 63mph

Kings Bay Naval Sub Base: 65mph winds, wind gage failed.

Buck Island, FL: 73mph wind gust

Buoy, 42 miles ENE of St Augustine FL: sustained peak wind of 51mph gust to 67mph, pressure 994mb.

2011 versus 2012 Rainfall:

While the last few weeks have been very dry, rainfall for the first part of 2012 has been extremely heavy with some locations recording their first or second wettest year to date starts on record. Most locations are averaging between 3-4 times greater rainfall in 2012 compared to 2011.

Sugar Land: 5.89 vs 30.18 (over 5 times the amount of rainfall in 2012 compared to 2011)

College Station: 7.66 vs 23.12

Crockett: 12.03 vs 21.65

Bush IAH: 6.96 vs 22.24

Hobby: 5.40 vs 26.29

Galveston: 7.73 vs 20.82

Matagorda: 5.31 vs 21.44

Tomball: 4.32 vs 13.63

Victoria: 6.13 vs 11.81

[Quixotic1]

Pea sized and nickel sized hail IMBY. Wasn't big, but man there was a lot of it and the noise was insane. Combined with the gusty winds and constant lightning, the 10 people visiting from out of town were up at 3 am in a panic. Am hopeful for later today because of this from the SPC, but I'm doubtful of the CAPE recovering.

...CNTRL/SRN PLAINS...

12Z SURFACE OBSERVATIONS SHOW THAT A CONVECTIVE OUTFLOW ASSOCIATED

WITH DECAYING MCS OVER N-CNTRL/NERN TX EXTENDS FROM NEAR LFK NWWD

THROUGH ACT TO A SURFACE LOW N OF LBB. VAD DATA FROM FREDRICK OK

AND OK MESONET OBSERVATIONS INDICATE THAT THIS BOUNDARY IS QUITE

SHALLOW OVER SWRN OK/NWRN TX WHERE SURFACE WINDS HAVE ALREADY VEERED

TO A SELY DIRECTION. AND WHILE DEWPOINTS HAVE DROPPED INTO THE

UPPER 50S AT MANY LOCATIONS ACROSS THE WRN HALF OF OK...INCREASED

BOUNDARY LAYER MIXING WILL LIKELY RESULT IN VALUES INCREASING INTO

THE LOW/MID 60S LATER TODAY. AT THE SAME TIME...A PLUME OF VERY

STEEP MIDLEVEL LAPSE RATES /I.E. 8.5-9.5 C PER KM/ WILL OVERSPREAD

WARM SECTOR AND CONTRIBUTE TO A MODERATE-STRONGLY UNSTABLE AIR MASS

BY AFTERNOON WITH MLCAPE RANGING FROM 1000-1500 J/KG IN SWRN NEB TO

AS HIGH AS 3000-4000 J/KG ACROSS PARTS OF WRN OK.

CONSIDERABLE VARIABILITY EXISTS AMONGST MESOSCALE AND

CONVECTION-ALLOWING MODEL GUIDANCE WITH REGARD TO SPECIFIC DETAILS

OF CONVECTIVE EVOLUTION THIS AFTERNOON INTO EVENING. CURRENT

THINKING IS THAT THE PREFERRED CORRIDOR FOR STORM INITIATION WILL BE

ACROSS WRN PARTS OF KS/OK BY MID AFTERNOON WHERE LARGE-SCALE FORCING

FOR ASCENT PROGRESSIVELY OVERSPREADS WRN/NWRN EXTENSION OF WARM

SECTOR. FORECAST HODOGRAPHS INDICATE VERTICALLY VEERING WIND

PROFILES /MOST NOTABLY ACROSS WRN KS/ WITH 45-55 KT OF EFFECTIVE

BULK SHEAR WHICH WILL SUPPORT RAPID SUPERCELL EVOLUTION.

VERY LARGE HAIL AND A FEW TORNADOES WILL BE POSSIBLE WITH THE

INITIAL STORMS BEFORE ACTIVITY GROWS UPSCALE INTO ONE OR MORE

FORWARD-PROPAGATING MCSS. LARGE-SCALE PATTERN IS ANALOGOUS TO PAST

CNTRL/SRN PLAINS DERECHO EVENTS...AND A SIMILAR TYPE SCENARIO MAY

UNFOLD THIS EVENING INTO TONIGHT WITH THE POTENTIAL FOR WIDESPREAD

DAMAGING WINDS FROM PARTS OF SRN KS THROUGH WRN/CNTRL OK INTO NRN

TX.

[Srain]

Morning e-mail from Jeff:

Lots to talk about this morning as our quite pattern of late breaks down into a brief active pattern.

Morning visible images shows a large outflow boundary extending from NW LA across eastern TX westward across Houston County to north of College Station with multiple gravity waves noted moving SW across central TX. This is all a result of the large complex of storms which moved out of OK into N TX overnight. Additional activity has developed over OK into north TX this morning in a N/S band and is slowly moving SSW. Satellite is also showing well defined cloud street moving inland off the NW Gulf this morning…a sign that the air mass is very moist in the low levels and this is confirmed by widespread dewpoints in the low to mid 70’s over the region.

High Resolution models show the eastern TX outflow boundary making it well into SE TX this afternoon and it is very possible a few showers/thunderstorms may develop along this feature. Corpus soundings continues to show a monster cap in place in the mid levels and this is forecasted to be maintained today into Thursday, so expect activity today to be fairly isolated and mainly confined east of I-45 where the capping is expected to be weakest.

Thursday-Friday Morning:

Cold front over OK this morning will move southward and enter SE TX during peak heating on Thursday. Surface temperatures forecasted in the low to mid 90’s with dewpoints in the low 70’s will support extreme instability by mid afternoon across the region. SBCAPE values rise to near 4000 J/kg along with steepening mid level lapse rates all supporting deep convective development. Negative factor continues to be warm mid level air from high pressure aloft located just south/southwest of the region. Models seem to be converging on the weakening of this capping and the strong lift/convergence with the front enough to overcome any remaining capping. Large scale model rain chances are fairly low on Thursday (less than 20%) while some of the meso models are a little more bullish with activity. I am tempted to side with the wetter solution especially or areas along and north of I-10 where the capping will be weaker and we will likely see decent coverage. South of I-10 and especially around Matagorda Bay, the cap intensity will control the coverage and intensity of the storms and think the warm mid levels will win out.

Given the extreme amounts of instability likely by Thursday afternoon, any storms that develop will likely quickly go severe with very large hail and damaging winds the main threats. Warm surface temperatures will make for very gusty outflow winds and large outflow boundaries may collide with the seabreeze front later in the afternoon/early evening at some location (possibly near/just north of I-10) which could help keep activity going well into the evening hours. SPC has included much of the area in a slight risk for severe weather on Thursday and will review the threat again and better define on Thursday morning.

Weak frontal boundary should clear the coast early Friday morning ending the threat for additional rainfall. A slightly cooler and drier air mass likely the last until fall will advect into the region providing nice early summer weather (lows in the 60’s and highs in the upper 80’s to near 90). Gulf moisture begins its return by Sunday and expect a more typical summer pattern to entrench into the region next week with ridging aloft slightly weaker allowing some daily development along the seabreeze front each afternoon.

[DoctorMu]

Yeah, that NW flow is brining down a few storms from OK, mostly E of I-45. Some de-CAP-itation going on, but they have enough jouce to bring some showers in a day ahead of a much needed cold front and plow needed for lifting and a taste of moisture, mostly N of I-10

[Ed Lizard]

Modelling does not look quite as gung ho enthusiastic about meaningful rain in SETX as I would hope tomorrow, but as always, glass full optimist.