June: Onshore Flow Returns With Increasing Gulf Moisture

[Portastorm]

The forecasters at EWX also mentioned the upper-level disturbance tomorrow and the possibility of severe, pulse-type storms for its forecast area (south central Texas). Also see where the GFS is suggested an inverted trough along the coast this weekend while the Euro has it as an upper-level low. Either way, it could mean rain for us! Hoping ...

[weatherguy425]

12z GFS looks drier int he Medium and Longer range, and last night's 0z keeps most most of the moisture in south Texas with it's modeled ULL. Hopefully we can at least get seabreeze convection to fire.


Regarding tomorrow, models (so far) seem slightly more bullish with storm chances.

[srainhoutx]

For our Central Texas neighbors. I just hit 100F in my backyard as well...Hobby has been at 100F for the past two hours...

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
253 PM CDT MON JUN 25 2012

...HEAT ADVISORY IN EFFECT FOR SOUTH CENTRAL TEXAS FROM NOON
TUESDAY UNTIL 9 PM TUESDAY...

.UPPER LEVEL HIGH PRESSURE CONTINUING ACROSS THE REGION WILL LEAD
TO TEMPERATURES CLIMBING TO ABOVE 100 DEGREES AGAIN ON TUESDAY.
AFTERNOON HIGHS ARE EXPECTED TO RANGE FROM 102 TO 107...WITH HEAT
INDEX VALUES OF 105 TO 110. TEMPERATURES WILL FALL INTO THE MID 90S
AFTER SUNSET...HOWEVER...LOW TEMPERATURES WEDNESDAY WILL FALL
ONLY TO THE UPPER 70S TO NEAR 80 ACROSS MUCH OF THE REGION. HIGH
TEMPERATURES ON WEDNESDAY ARE EXPECTED TO RANGE FROM THE UPPER 90S
TO NEAR 104.

TXZ171>173-183-190>194-202>209-217>225-228-261200-
/O.NEW.KEWX.HT.Y.0002.120626T1700Z-120627T0200Z/
LLANO-BURNET-WILLIAMSON-VAL VERDE-BLANCO-HAYS-TRAVIS-BASTROP-LEE-
KINNEY-UVALDE-MEDINA-BEXAR-COMAL-GUADALUPE-CALDWELL-FAYETTE-
MAVERICK-ZAVALA-FRIO-ATASCOSA-WILSON-KARNES-GONZALES-DE WITT-
LAVACA-DIMMIT-
INCLUDING THE CITIES OF...LLANO...BURNET...GEORGETOWN...DEL RIO...
BLANCO...SAN MARCOS...AUSTIN...BASTROP...GIDDINGS...
BRACKETTVILLE...UVALDE...HONDO...SAN ANTONIO...NEW BRAUNFELS...
SEGUIN...LOCKHART...LA GRANGE...EAGLE PASS...CRYSTAL CITY...
PEARSALL...PLEASANTON...FLORESVILLE...KARNES CITY...GONZALES...
CUERO...HALLETTSVILLE...CARRIZO SPRINGS
253 PM CDT MON JUN 25 2012

...HEAT ADVISORY IN EFFECT FROM NOON TO 9 PM CDT TUESDAY...

THE NATIONAL WEATHER SERVICE IN AUSTIN/SAN ANTONIO HAS ISSUED A
HEAT ADVISORY...WHICH IS IN EFFECT FROM NOON TO 9 PM CDT TUESDAY.

* TEMPERATURE...HIGH TEMPERATURES WILL RANGE FROM 102 TO 107. HEAT
INDEX READINGS WILL RANGE FROM 105 TO 110.

* IMPACTS...PROLONGED EXPOSURE TO THE HEAT MAY LEAD TO HEAT EXHAUSTION
AND HEAT STROKE.

[Belmer]

Yes, here in San Marcos it is absolutey sizzling!! Thankfully I don't have the Houston humidity, but it's currently 99 degrees with little to no wind. I am not looking forward to the 105-107 degree weather tomorrow.

[Portastorm]

Yeah at 3 p.m. we have 102 at Camp Mabry and 101 at Austin Bergstrom. Well, at least it's a dry heat.

[srainhoutx]

HGX mentioning an inverted V signature in 00Z sounding with PW's of 1.9 and convective temps near 100F capable of breaking the cap. The SPC does have a See Text issued for the S Central/SE Texas Region. We'll see if storms can fire as a disturbance drops SW from Arkansas later today as a boundary approaches. The SREF suggests we could see additional storm chances on Wednesday as well. The ridge does appear to weaken over the coming weekend and a return flow off the Gulf brings sea breeze showers/storms during the upcoming weekend as we start the month of July. We will continue those discussion in the July Topic as well as look ahead to Independence Day.

...EAST/SOUTH-CENTRAL TX...
ON THE EAST-SOUTHEAST PERIPHERY OF AN EXTENSIVE FOUR CORNERS/PLAINS
UPPER RIDGE...ISOLATED TSTMS SHOULD DEVELOP WITHIN A HOT/UNSTABLE
BOUNDARY LAYER ALONG/AHEAD OF A SOUTHWESTWARD-SHIFTING COLD FRONT
THIS AFTERNOON/EARLY EVENING. IF/WHERE STORMS DO FORM...A DEEPLY
MIXED ENVIRONMENT WOULD ALLOW FOR DOWNBURSTS/DAMAGING WINDS.

[srainhoutx]

SPC issues Slight Risk for Severe Storms for portions of SE/S Central Texas...

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0751 AM CDT TUE JUN 26 2012

VALID 261300Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE NRN PLNS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF FL...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF ERN AND SRN TX...

...SYNOPSIS...
AMPLIFIED...EXPANSIVE RIDGE WILL REMAIN OVER THE CNTRL/SRN PLNS THIS
PERIOD...FLANKED BY UPR TROUGHS/LOWS OVER THE PACIFIC NW/NRN
RCKYS...AND NEW ENGLAND. ELSEWHERE...T.S. DEBBY EXPECTED TO TRACK
SLOWLY E TO ENE ACROSS THE NERN GULF THROUGH THE PERIOD PER NHC
FORECAST.

...MT/NRN PLNS TODAY/TNGT...
NEGATIVE TILT SHORTWAVE TROUGH NOW OVER ORE EXPECTED TO CONTINUE NE
INTO CNTRL ID THIS AFTN...AND INTO SRN AB TNGT...WITH ASSOCIATED
STRENGTHENING SWLY MID/UPR LVL FLOW OVERSPREADING NRN MT AND ND.
INCREASING FORCING FOR ASCENT LIKELY WILL SUPPORT CONTINUED
DEVELOPMENT OF SCTD TSTMS IN ZONE OF LOW LVL WAA OVER NRN MT THROUGH
MIDDAY. WHILE MOST OF THE STORMS SHOULD REMAIN SOMEWHAT ELEVATED
ATOP EARLIER STORM OUTFLOW AND COLD FRONT ASSOCIATED WITH THE UPR
TROUGH...THEY COULD YIELD SVR HAIL AND PERHAPS LOCALLY DMGG WIND.

A MORE SUBSTANTIAL SVR RISK MAY DEVELOP TOWARD EARLY AFTN ACROSS FAR
NW/NRN MT AS DIURNAL HEATING ALLOW STORMS TO BECOME MORE NEARLY
SFC-BASED...AND BEFORE STRONGER FORCING FOR ASCENT SHIFTS NWD BEYOND
REGION. SUCH ACTIVITY COULD YIELD AN INCREASED RISK FOR DMGG WIND
AND PERHAPS A TORNADO OR TWO BEFORE THE STORMS MOVE N INTO CANADA.

FARTHER E...OTHER POTENTIALLY STRONG/SVR TSTMS MAY FORM OVER THE WRN
DAKOTAS NEAR LEE LOW/TROUGH. WHILE APPRECIABLE CAPPING COULD LIMIT
THE EXTENT OF SVR THREAT...AT LEAST A FEW STORMS CAPABLE OF
SVR HAIL/WIND WILL BE POSSIBLE...MAINLY IN WRN ND.

...FL TODAY THROUGH EARLY WED...
SLOW ENE MOVEMENT OF T.S. DEBBY WILL MAINTAIN A MOIST...MODERATELY
SHEARED ENVIRONMENT ACROSS THE FL PENINSULA THROUGH EARLY WED. EWD
MOTION OF DEBBY AND ITS PERIPHERAL INTERACTION WITH UPR TROUGH OVER
THE NE U.S. MAY KEEP LWR TROPOSPHERIC FLOW OVER THE REGION SOMEWHAT
VEERED RELATIVE TO RECENT DAYS. NEVERTHELESS...PRESENCE OF 40+ KT
700 MB FLOW ATOP VERY MOIST BOUNDARY LAYER IN THE PRESENCE OF SFC
HEATING SUGGESTS THE POTENTIAL FOR BANDS OF STORMS WITH BOWING
SEGMENTS/DMGG WIND OVER CNTRL AND SRN PARTS OF THE PENINSULA...AND
AT LEAST A LOW RISK FOR TORNADOES...ESPECIALLY THIS AFTN. MORE
ISOLD ROTATING STORMS ALSO COULD ARISE ON AN INTERMITTENT BASIS
THROUGH EARLY WED NEAR WSW-ENE CONFLUENCE/WEAK BACK-DOOR BOUNDARY
ACROSS N FL.

...ERN THROUGH S CNTRL TX THIS AFTN/EVE...
ON THE ESE SIDE OF EXPANSIVE UPR RIDGE...SCTD TSTMS SHOULD FORM IN
HOT/UNSTABLE BOUNDARY LAYER ALONG/AHEAD OF WEAK BACK-DOOR COOL FRONT
MOVING SW FROM THE ARKLATEX. WIND PROFILES ACROSS ERN AND SE TX
WILL FEATURE 15-30 KT...LARGELY UNIDIRECTIONAL ENELY FLOW IN THE
700-500 MB LAYER. COUPLED WITH DEEPLY MIXED...HIGH PW
ENVIRONMENT...THE STORMS MAY EVOLVE INTO A FEW CLUSTERS THAT
PROPAGATE SW OR WSW TOWARD THE LWR RIO GRANDE VLY. THESE COULD
YIELD ISOLD DOWNBURSTS/LOCALLY DMGG WIND THROUGH EARLY TNGT.

...CO/WY FRONT RANGE AND ADJACENT HIGH PLNS THIS AFTN/EVE...
SCTD TSTMS EXPECTED THIS AFTN/EVE OVER NE CO AND ERN WY AS ARC OF
MID LVL MOISTURE STREAMING NNE ON WRN FRINGE OF PLNS RIDGE INTERACTS
WITH TERRAIN CIRCULATIONS AND HOT/DEEPLY MIXED BOUNDARY LAYER
EXTENDING E INTO THE ADJACENT HIGH PLNS. WITH SUCH DEVELOPMENT
OCCURRING W OF APPRECIABLE LOW LVL MOISTURE...SBCAPE WILL REMAIN
LIMITED. NEVERTHELESS...STEEP LOW TO MID LVL LAPSE RATES/INVERTED-V
PROFILES COULD YIELD ISOLD DOWNBURSTS/LOCALLY DMGG WIND.

...MAINE/CSTL NEW ENGLAND TODAY...
A CLUSTER OR TWO OF LOW-TOPPED TSTMS MAY FORM TODAY OVER CSTL NEW
ENGLAND...NEAR LOW LVL CONFLUENCE AXIS ROTATING SE BENEATH UPR LOW.
OTHER STORMS MAY CONTINUE TO DEVELOP IN WARM CONVEYOR BELT FARTHER E
ACROSS ERN ME. A FEW OF THE STORMS COULD YIELD HAIL...BUT MEAGER
BUOYANCY SHOULD LIMIT ANY SVR THREAT.

..CORFIDI/GARNER.. 06/26/2012

[srainhoutx]

Morning e-mail from Jeff:

Record heat will continue one more day over the area bringing back memories of 2011…but the heat will not last to the length or severity of 2011. See section below on heat records.



Massive upper level ridge centered over the central plains continues to produce widespread 100+ degree afternoon temperatures. Drier air above the surface will continue to mix down in the early to mid afternoon hours and this has been lowering dewpoints and RH values resulting in heat index values of less than the 108 needed to issue a heat advisory. Overnight lows have been falling mainly into the upper 70’s except for the urban areas where lows have been in the lower 80’s. We are right on the cusp of the required criteria for a heat advisory, but at this time we do not meet the standards. We see most locations head for the low to mid 100’s this afternoon (100-105) with heat index values of 104-109.



Severe Threat:

With the air mass becoming super heated by midday (upper 90’s) and a short wave approaching from the NE with a pool of deeper moisture expect to see a few thunderstorms develop as intense heating breaches the hot trigger temperatures. NAM and GFS forecast soundings are very similar for this afternoon showing a strong inverted “V” or upside down goal post sounding indicating high cloud bases and dry air below the cloud bases. With the GFS forecast sounding is showing the cloud bases in the 850-800mb range (or between about 6600 and 7500 ft) above the ground and then rapidly falling dewpoints and rising temperatures below this level supporting the dry sub-cloud layer. This points strongly toward some of the rainfall evaporating as it begins to fall from the cloud base and developing strong downward momentum. Additionally, temperatures in the 800-900mb level will be in the 55-70 degree range and this will combine with the evaporation to help produce strong downburst winds and rapidly spreading outflow boundaries. Damaging winds to 60-70mph will be possible with any storms that develop this afternoon and outflow winds of 40-50mph will be possible even well away from the storms as the cooler and drier air aloft clashes with the near surface low 100 degree heat. Storms will likely continue into the evening hours as the air mass will remain very warm (mid to upper 90’s) past 900pm).





Climate:

Record highs fell at several sites yesterday including an impressive record at Palacios.



The high at Palacios reached 102 degrees and this is the hottest June temperature ever recorded at this location and ties (Sept 3, 2011) for the 3rd warmest temperature ever at this site.



Galveston reached 100 degrees yesterday for only the 8th time ever. The daily high temperature record of 96 in 1875 was broken. Galveston had never recorded a June temperature of 100 before yesterday. It is interesting to note that of the 8 times Galveston has reached 100 degrees, 5 of those times have been since 2000!



The records on the coast were due to weak NW winds helping to keep the seabreeze boundary very near the beaches or even offshore and allowing the inland heat to be pushed toward the coastal sites.





Records high for Monday, June 25:

Galveston: 100 (old record 96 in 1875)

BUSH IAH: 102 (tied record of 102 in 2009)

Hobby: 102 (tied record of 102 in 2009)

Corpus Christi: 105 (old record 99 in 2009)

Victoria: 106 (old record 103 in 2009)

San Antonio: 103 (tied record of 103 in 2009)

Palacios: 102 (old record 96 in 1984)

Angleton: 101 (old record 99 in 2009)

League City: 101 (old record 99 in 2009)

[weatherguy425]

For Today:

Convective temps are already close to being met here on the north side as of 12:30, and a small but agitated cumulus field is developing northwest of Jasper moving southwest. Some of the latest RAP model runs have grown more bullish with afternoon/evening convection but at the same time aren't yet verifying with their reflectivity modeled for the current time. Here's to hoping for at least some isolated storms later.

For this weekend/next week:

12z GFS continues the slightly wetter trend for this weekend and very early next week, though amounts are pretty dismal and spotty with maybe a few yards picking up >1/2 an inch. As srainhoutx pointed out, lat night's runs, especially the ECMWF were starting a more favorable trend towards rain. Unfortunately today's GFS shows the tropical wave and associated moisture moving in and out fairly quickly with high pressure trying to re-assert itself around Tuesday of next week, still waiting for today's ECMWF.

I really hope this summer turns around, but longer range models really aren't offering that much hope, even here along the coast. Dry ground, dying trees, and drying lakes are really getting old....

[srainhoutx]

I'm beginning to get some high based CU development here in NW Harris County. Bases look to be near 9-10K. Current temp up here is 102F.

[Portastorm]

Yeah, the severe threat appears to be growing based on the SPC discussion. The winds from any of these storms are going to be something else!

[srainhoutx]

I'm beginning to get some high based CU development here in NW Harris County. Bases look to be near 9-10K. Current temp up here is 102F.

http://www.spc.noaa.gov/products/md/md1289.html

35ºF T/Td spreads, haboob city?

MESOSCALE DISCUSSION 1289
NWS STORM PREDICTION CENTER NORMAN OK
0202 PM CDT TUE JUN 26 2012

AREAS AFFECTED...S-CNTRL/SERN TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 261902Z - 262100Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...AT LEAST ISOLATED HIGH-BASED TSTMS SHOULD FORM WITHIN A
HOT THERMODYNAMIC ENVIRONMENT BY LATE AFTERNOON. WITH MODERATE
MID-LEVEL NELYS...UPDRAFTS COULD COALESCE INTO AN ORGANIZED CLUSTER
WITH THREATS OF ISOLATED SEVERE WIND AND HAIL.

DISCUSSION...CU HAS INCREASED IN THE PAST HOUR IN VISIBLE SATELLITE
IMAGERY ALONG THE COASTAL PLAIN AND HILL COUNTRY. PRESENCE OF
SCATTERED CIRRUS SUGGESTS A SUBTLE UPPER-LEVEL IMPULSE ALONG THE WRN
GULF COAST MAY BE ENHANCING ASCENT. WITH SURFACE TEMPERATURES NOW
REACHING 100-105...MLCIN SHOULD BE WEAK WITH A DEEPLY-MIXED BOUNDARY
LAYER PER ACARS DATA INVOF AUS. GUIDANCE IS FAIRLY CONSISTENT THAT
TSTMS SHOULD FORM...ALTHOUGH THE LACK OF WELL-DEFINED
SURFACE/UPPER-LEVEL FEATURES BREEDS UNCERTAINTY IN WHERE DEVELOPMENT
WILL FOCUS. NEVERTHELESS...PRESENCE OF 30-35 KT MID-LEVEL NELYS
SAMPLED IN THE LEDBETTER TX PROFILER WOULD BE SUFFICIENT FOR
ORGANIZING UPDRAFTS. THE STEEP LAPSE RATE ENVIRONMENT SHOULD PROMOTE
RISKS FOR SEVERE WIND AND SOME HAIL.

..GRAMS/WEISS.. 06/26/2012


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

[jasons2k]

60% of watch issuance - I'll take it...

[srainhoutx]

60% of watch issuance - I'll take it...

Jason, the developing TCU field extends NE to SSW from Walker, Montgomery, Western Harris and points W. Portastorm may well get in on some action later this afternoon. Looking to my SE, hardly a cloud in the sky. But over head and looking N and W, the CU field is percolating.

[wxman57]

It's EXTREMELY dry aloft over downtown Houston now. Virtually no moisture except for a small layer a few hundred feet thick 4-6 thousand feet up.

[Belmer]

Here in San Marcos, clouds have recently been popping up and getting slightly bigger.
I've been back in San Marcos since June 3rd and since then, we've only seen a trace of rainfall and that fell in the very beginning of June. Very dry here, grass is all brown and yellow. Hoping we can get some rain later today.

[srainhoutx]

Getting some rumbles of thunder up here now. Cell developing just to the W of Cypress it appears.

[jasons2k]

Fast movers too...I hope there is a chance of more behind those. The shape of the MCD does concern me, if it means the energy dropping down from the NE will pass us by very quickly (over before it can get started). ?

[srainhoutx]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0256 PM CDT TUE JUN 26 2012

VALID 262000Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NRN HIGH PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SOUTH TX...

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE FL PENINSULA...

EARLIER THOUGHTS REGARDING NRN HIGH PLAINS CONVECTION LARGELY
REMAIN. ONGOING NW-SE BROKEN LINE OF TSTMS IS PROGRESSING NEWD AT
ROUGHLY 40KT. THIS ACTIVITY WILL STRUGGLE TO DEVELOP SWD BUT RATHER
BE SHUNTED INTO SK WHERE LARGE SCALE ASCENT IS EXPECTED TO FOCUS.
DOWNSTREAM...THERE IS INCREASING CONCERN THAT INTENSE HEAT ACROSS
THE PLAINS OF SERN MT WILL YIELD HIGH-BASED CONVECTION OVER THE NEXT
SEVERAL HOURS. LATEST VIS IMAGERY DEPICTS AN EXPANDING CU FIELD
EAST OF BIL TOWARD THE NRN BLACK HILLS REGION WHERE A DEVELOPING
SHOWER IS NOTED OVER BUTTE COUNTY SD. WITH SFC TEMPERATURES NOW IN
EXCESS OF 100F FROM MLS TO RAP IT WOULD SEEM THAT DEEP CONVECTION
MAY SOON DEVELOP/MATURE. AN AXIS OF MOISTURE HOLDS JUST DOWNSTREAM
ACROSS NERN MT/WRN DAKOTAS AND FOR THIS REASON WILL INCREASE SEVERE
PROBS ACROSS THE NRN HIGH PLAINS AND A SLIGHT RISK WILL BE ADDED TO
ACCOUNT FOR THIS EVOLUTION.

FARTHER SOUTH ACROSS TX...CU FIELD IS EXPANDING IN AREAL COVERAGE
AND DEPTH AS SFC TEMPERATURES SOAR ABOVE 100F. OVER THE LAST HOUR
OR SO TOWERING CU HAS DEVELOPED NORTH OF HOU. IN ALL LIKELIHOOD A
FEW THUNDERSTORMS WILL EVOLVE ACROSS THIS REGION WITH WSWWD
MOVEMENT/PROPAGATION EXPECTED TOWARD SCNTRL TX. ISOLATED DAMAGING
DOWNBURSTS ARE THE GREATEST CONCERN.

..DARROW.. 06/26/2012

[srainhoutx]

HGX will be switching from 'clear air mode' shortly...