June: Onshore Flow Returns With Increasing Gulf Moisture

[mckinne63]

Hearing thunder in Stafford. Was breezy, but now is very still. Calm before the storm?

[Rip76]

Looks like it's staying away...

[srainhoutx]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0751 AM CDT SAT JUN 30 2012

VALID 301300Z - 011200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE OH VALLEY TO
MID ATLANTIC COAST...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE NRN/CNTRL
PLAINS INTO LOWER MO VALLEY...

...SYNOPSIS...

A HIGH-LATITUDE OMEGA BLOCK WILL BECOME BETTER-DEFINED WITH
TIME...FEATURING AN AMPLIFYING RIDGE OVER THE CANADIAN PRAIRIE
PROVINCES INTO NRN HIGH PLAINS AND EVOLVING TROUGHS OVER WRN
CANADA/PACIFIC NW AND ERN CANADA/NERN U.S. WITHIN THIS
BROADER-SCALE FLOW REGIME...A VORTICITY MAXIMUM OF CONVECTIVE ORIGIN
OVER WRN OH WILL TRANSLATE EWD...REACHING THE MID ATLANTIC COAST BY
01/00Z...WHILE UPSTREAM A MULTI-BRANCH SERIES OF IMPULSES MOVE INTO
THE NRN/CNTRL PLAINS.

AT THE SURFACE...THE PRIMARY BAROCLINIC ZONE WILL EXTEND FROM A
HEAT/LEE LOW OVER NERN CO/NWRN KS EWD THROUGH THE LOWER MO VALLEY TO
A COMPOSITE SYNOPTIC-OUTFLOW BOUNDARY TRAILING DECAYING OH MCS. E
OF THE APPALACHIANS...OUTFLOW BOUNDARY ASSOCIATED WITH THE FRIDAY
EVENING/NIGHT DERECHO-PRODUCING MCS HAS SETTLED INTO THE CAROLINAS.
EXPECT THIS BOUNDARY RE-DEVELOP NWD INTO THE DELMARVA TODAY WITHIN
STRENGTHENING LOW-LEVEL WAA REGIME ASSOCIATED WITH APPROACHING OH
VALLEY VORTICITY MAXIMUM. OVER THE NRN PLAINS...AN INVERTED TROUGH
WILL SHIFT EWD ACROSS THE DAKOTAS WITH THE SRN EXTENSION OF BOUNDARY
LINKING WITH LEE LOW OVER THE CNTRL HIGH PLAINS.

...OH VALLEY TO MID ATLANTIC COAST THIS AFTERNOON INTO TONIGHT...

LATEST CONVECTION-ALLOWING AND MESOSCALE MODEL GUIDANCE SUGGEST THAT
THE PRIMARY SEVERE WEATHER THREAT WILL BE FOCUSED ALONG OUTFLOW
BOUNDARY ASSOCIATED WITH DECAYING OH MCS AS IT EMERGES FROM THE
CREST OF THE APPALACHIANS LATER TODAY. HERE...UPLIFT ALONG THE
RESIDUAL OUTFLOW BOUNDARY/GUST FRONT WILL COINCIDE WITH DEEPER-LAYER
FORCING ASSOCIATED WITH MCV TO PROMOTE AN INCREASE IN TSTMS WITHIN A
MOIST/MODERATELY UNSTABLE AIR MASS WITH MLCAPE APPROACHING 1500-3000
J/KG. KINEMATIC ENVIRONMENT WILL FEATURE A UNIDIRECTIONAL WNWLY
WIND FIELD WITH 50-60 KT FLOW POSSIBLE IN THE 600-500-MB LAYER PER
12Z UPSTREAM SOUNDING AT WILMINGTON OH. AS SUCH...POTENTIAL WILL
EXIST FOR THE EVOLUTION OF ANOTHER BOW ECHO SYSTEM CAPABLE OF
POTENTIALLY WIDESPREAD DAMAGING WINDS ACROSS PARTS OF THE DELMARVA
INTO CNTRL/ERN NC.

MEANWHILE...A SMALL CLUSTER OF TSTMS HAS RECENTLY INTENSIFIED OVER
SERN IA...APPARENTLY FORCED BY A WEAK SHORTWAVE TROUGH PROGRESSING
SEWD THROUGH SRN MN/NRN IA. THOUGH NOT WELL RESOLVED BY THE
MODELS...IT IS POSSIBLE THAT THESE STORMS COULD INTENSIFY BY LATE
MORNING/EARLY AFTERNOON OVER PARTS OF E-CNTRL IL/W-CNTRL INDIANA.
WHILE ENVIRONMENT IS NOT NEARLY AS UNSTABLE AS FRIDAY...12Z
SOUNDINGS INDICATE THE POTENTIAL FOR MODERATE-STRONG INSTABILITY
/I.E. MLCAPE VALUES OF 1500-3000 J PER KG/ IN THE PRESENCE OF MODEST
VERTICAL SHEAR. AS SUCH...EVOLUTION OF AN ADDITIONAL
FORWARD-PROPAGATING MCS/BOW ECHO IS POSSIBLE WITH A HEIGHTENED RISK
FOR DAMAGING WINDS SPREADING EWD TOWARD THE UPPER OH VALLEY. DUE TO
LOWER CONFIDENCE IN THIS SCENARIO...ONLY BASELINE SLIGHT RISK
PROBABILITIES WILL BE INCLUDED IN THIS FORECAST.

...NRN/CNTRL PLAINS INTO LOWER MO VALLEY THIS AFTERNOON AND
EVENING...

STEEP MIDLEVEL LAPSE RATES AND BOUNDARY LAYER DEWPOINTS IN THE UPPER
50S-UPPER 60S ARE EXPECTED TO CONTRIBUTE TO A MODERATE-STRONGLY
UNSTABLE ENVIRONMENT BY AFTERNOON WITH MLCAPE VALUES RANGING FROM
2000-4000+ J/KG ALONG INVERTED TROUGH AND ALONG COOL SIDE OF W-E
ORIENTED QUASI-STATIONARY BOUNDARY. LOW-LEVEL CONVERGENCE/ASCENT
ALONG SURFACE BOUNDARIES WILL BE AUGMENTED BY FORCING ASSOCIATED
WITH MULTIPLE WEAK MIDLEVEL IMPULSES...AND STRONG BOUNDARY LAYER
HEATING S OF FRONT IN KS TO FOSTER MULTIPLE CLUSTERS OF TSTMS THIS
AFTERNOON INTO TONIGHT.

THE STRONGEST WLY/WNWLY MIDLEVEL FLOW AND RESULTING VERTICAL SHEAR
WILL RESIDE ALONG DAKOTAS SEGMENT OF INVERTED TROUGH WHERE
SUPERCELLS CAPABLE OF LARGE HAIL AND DAMAGING WINDS ARE POSSIBLE.
FARTHER S...THE WEAKER VERTICAL SHEAR WILL BE COMPENSATED BY THE
STRONG INSTABILITY WITH ENVIRONMENT SUPPORTIVE OF MULTICELL CLUSTERS
CAPABLE OF DAMAGING WINDS AND HAIL.

...INTERIOR PACIFIC NW INTO NRN INTERMOUNTAIN REGION THIS AFTERNOON
AND EVENING...

LARGE-SCALE FORCING FOR ASCENT AND VERTICAL SHEAR WILL INCREASE
TODAY AHEAD OF SHORTWAVE TROUGH MOVING ONSHORE. THIS WILL COINCIDE
WITH STEEPENING LAPSE RATES AND CONCOMITANT INCREASE IN MOISTURE
WITH ENVIRONMENT BECOMING FAVORABLE FOR ISOLATED SEVERE STORMS
--INCLUDING SOME POSSIBLE SUPERCELL STRUCTURES-- WITH AN ASSOCIATED
RISK FOR DAMAGING WINDS AND HAIL. ANTICIPATED LIMITED AREAL
COVERAGE PRECLUDES THE ISSUANCE OF A CATEGORICAL SLIGHT RISK ATTM.

...MAINE THIS AFTERNOON...

ISOLATED SEVERE STORMS WILL ONCE AGAIN BE POSSIBLE THIS AFTERNOON AS
LARGE-SCALE FORCING FOR ASCENT IS ENHANCED BY SHORTWAVE TROUGH
MOVING ACROSS THE REGION. THE COMBINATION OF A RELATIVELY
MOIST/MODERATELY UNSTABLE AIR MASS AND 30-40 KT OF DEEP WLY SHEAR
MAY PROMOTE LINE SEGMENTS OR MULTICELL CLUSTERS WITH A RISK FOR
DAMAGING WINDS AND/OR HAIL.

...S TX TODAY...

12Z CRP/BRO SOUNDINGS SHOWED THE POTENTIAL FOR STRONG INSTABILITY TO
DEVELOP AHEAD OF TSTMS DEVELOPING ALONG THE COAST. LOCALLY DAMAGING
WINDS WILL BE POSSIBLE WITH ANY ORGANIZED CLUSTERS OWING TO COLD
POOL GENERATION VIA WATER LOADING EFFECTS.

..MEAD/HURLBUT.. 06/30/2012

[txflagwaver]

Hopefully not too much wind...with the promise of rain the plants are all moved out to enjoy the showers...getting tiny teaser droplets now

[Portastorm]

I find it interesting that JB mentioned this morning on Twitter that the area of disturbed weather off the Texas coast is basically the same area/time which some models last weekend showed Debby to be. We also saw several model runs which showed Debby's energy splitting, part to Florida and part to Texas, and most of us scoffed at that. Perhaps it wasn't so crazy after all?!

[srainhoutx]

The 12Z surface analysis suggest a trough lying along Coastal Texas from Corpus Christi to just S of High Island. Moisture continues to stream inland on the E side of the upper low currently N of Brownsville. As we warm further this afternoon, expect storms to fire inland and some lucky folks could see near 3 inch rainfall amount should training develop.

[srainhoutx]

Training storms beginning to develop from near Bellaire on NW up 290.

[spadilly]

getting a pretty good lightning show in spring branch with this storm.
loving the heavy rain!

[srainhoutx]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1152 AM CDT SAT JUN 30 2012

TXC201-301845-
/O.NEW.KHGX.FA.Y.0063.120630T1652Z-120630T1845Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
HARRIS TX-
1152 AM CDT SAT JUN 30 2012

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED AN

* URBAN AND SMALL STREAM FLOOD ADVISORY FOR...
WESTERN HARRIS COUNTY IN SOUTHEAST TEXAS...

* UNTIL 145 PM CDT

* AT 1151 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
VERY HEAVY RAIN WAS FALLING NEAR ADDICKS AND WEST OF JERSEY VILLAGE.
A CLUSTER OF STORMS WILL MOVE SLOWLY NORTHWEST BRINGING RAINFALL
RATES OF 2 INCHES PER HOURS OVER THIS REGION.

[srainhoutx]

TXC039-167-201-302015-
/O.NEW.KHGX.FA.Y.0064.120630T1815Z-120630T2015Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
HARRIS TX-BRAZORIA TX-GALVESTON TX-
115 PM CDT SAT JUN 30 2012

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED AN

* URBAN AND SMALL STREAM FLOOD ADVISORY FOR...
NORTHEASTERN BRAZORIA COUNTY IN SOUTHEAST TEXAS...
NORTHWESTERN GALVESTON COUNTY IN SOUTHEAST TEXAS...
SOUTHERN HARRIS COUNTY IN SOUTHEAST TEXAS...

* UNTIL 315 PM CDT

* AT 114 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
VERY HEAVY RAIN WAS FALLING NEAR FRIENDSWOOD. RAINFALL RATES AROUND
2 INCHES PER HOUR CAN BE EXPECTED AS A BAND OF STORMS DEVELOPS AND
MOVES NORTHWEST OVER THE AREA.

[jasons2k]

This is awesome - we're all getting a good rain today

We do need to keep an eye on the band forming over Galveston bay for training later on as it moves N/NW.

[srainhoutx]

So far I've had almost 2 inches from the first wave that came through earlier in NW Harris County. The next wave that Jason just mentioned is sweeping in from my SE. There appears to be another wave near Galveston Island as well.

[jasons2k]

It poured here with lots of thunder, but it was fairly brief as it morphed into a thin line. I got .43" with this first one - more to come

[Andrew]

More developing in the gulf to the south but dry air seems to be working its way in from the east.

http://www.ssd.noaa.gov/goes/east/gmex/flash-wv.html

[redneckweather]

Nope, not all of us have seen rain. I haven't seen jack at my house here in Montgomery County. Not much moving in either.

[weatherguy425]

Not quite sure when this was last updated, but PWATS still appear to be quite high. hopefully we'll get another round or two to give the unlucky few who haven't gotten any yet some needed rain.

[srainhoutx]

Getting close to 3 inches in the old rain bucket in my backyard. Stratiform rains now but HGX is painting a hopeful picture of a more typical SE Texas summertime pattern as we head into July...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
325 PM CDT SAT JUN 30 2012

.DISCUSSION...
UPPER LEVEL LOW OVER S TX WILL CONTINUE TO PUMP DEEP MOISTURE
INTO SE TX WITH SCT SHOWERS/THUNDERSTORMS. SOME OF THE STRONGER
STORMS HAVE PRODUCED 1-2 INCHES OF RAINFALL AN HOUR BUT STORMS
ARE MOVING AROUND 20 KTS SO HEAVY RAINFALL REMAINS LOCALIZED.
FLOODING PROBLEMS AND STREET FLOODING BECOME A PROBLEM IF STORMS
CONTINUE TO MOVE OUT OF THE GULF ACROSS SOME OF THE SAME AREAS
THAT HAVE HAD RAINFALL. PORTIONS OF HARRIS...BRAZORIA...GALVESTON
AND FORT BEND COUNTIES MAY NEED FFW IF MORE STORMS TRAIN OVER THE
SAME AREA LATER THIS AFTERNOON AND EVENING.

EXPECT A BREAK IN THUNDERSTORM ACTIVITY LATE THIS AFTERNOON BUT
LATEST RADAR AND SATELLITE IMAGERY SHOWS THUNDERSTORM ACTIVITY
STILL IN THE GULF MOVING TOWARDS THE COAST. MAY BE A FEW HOURS
BEFORE THIS ACTIVITY IMPACTS THE AREA AND FORECAST WILL KEEP SOME
CHANCE POPS IN THE FORECAST. GENERAL THINKING IS THAT STORMS WILL
DISSIPATE WITH LOSS OF DAY TIME HEATING. MODEL GUIDANCE SUGGESTS
ANOTHER ROUND OF STORMS TONIGHT INTO SUN MORNING. WILL KEEP 30/40
PERCENT POPS IN THE FORECAST TONIGHT INTO TOMORROW. UPPER LEVEL
LOW OVER S TX IS EXPECTED TO MOVE WEST TAKING WITH IT GOOD UPPER
LEVEL LIFT. THUNDERSTORM ACTIVITY SHOULD THIN OUT EARLY TOMORROW
AFTERNOON AND EXPECT A DRIER START TO THE WORK WEEK.

THE WORK WEEK IS SHAPING UP TO BE ON THE WARM SIDE BUT NOT QUITE
AS HOT AS THIS LAST WEEK. MAX TEMPS IN THE LOW/MID 90S VERSUS
UPPER 90S/LOW 100S. UPPER LEVEL RIDGE SHOULD BUILD OVER THE AREA
AGAIN BUT NOT QUITE AS STRONG. DEEP SE FLOW MAY HELP KEEP SOME
BETTER MOISTURE IN SE TX SO THINK TYPICAL SUMMER TIME AFTERNOON
STORMS WILL BE POSSIBLE AFTER A FEW SHOWERS IN THE MORNING WITH
THE ONSHORE FLOW. THIS MEANS GOING WITH THE 20 POPS FOR THE
MORNING ALONG THE COAST AND MOVING THAT CHANCE INLAND DURING THE
DAY. MAX TEMPS LOOK TO BE A TOUCH WARMER THAN WHAT GUIDANCE
SUGGESTS ESPECIALLY MID TO LATE WEEK. MAY HAVE ANOTHER
DISTURBANCE MOVE INTO THE AREA FROM THE EAST WHICH COULD SUPPORT
BETTER RAIN CHANCES FOR THE END OF THE WEEK AND NEXT WEEKEND.

[Portastorm]

Nope, not all of us have seen rain. I haven't seen jack at my house here in Montgomery County. Not much moving in either.

I share your frustration ... here in south central Texas, namely the Austin area ... the Great Austin Rain Shield is working well and today, once again, evaporated a mass of rain moving in from the coast. I know we had less than a tenth of an inch of rain in June. My backyard has cracks in the dirt. Hate it.

[txflagwaver]

Went to Katy for a family function....drove through blinding rain...rained for a couple of hours delaying the outside part of the party...got home around 8...not a drop here


Getting showers here since about 11:15. Not heavy for very long...but steady and I'll take it! Even a clap or two of thunder for good measure

[jasons2k]

.48" yesterday, .05" overnight = .53" storm total. Hoping for more today