June: Onshore Flow Returns With Increasing Gulf Moisture

[srainhoutx]

The 12Z GFS continues to advertise a transition to a warm cored mid level low over Central Texas. That model also suggests that showers/storms will be on the increase beginning tomorrow across the region. I would not be surprised to see Flash Flood Watches hoisted for parts of Texas later today or tomorrow.

[MontgomeryCoWx]

Agreed Portastorm... this is a pretty interesting week of weather given the possibilities.

I would love to see 4 inches on the lawn.

[srainhoutx]

CU field continues to develop along the left over boundary. 12Z soundings from Corpus also suggest the cap has fully eroded and it is also interesting to note a bit of mid/low circulation offshore in Gulf in a very shear environment...

06052012 TC Formation Real Time 12Z gexyrfpr.png (11.68 KiB) Viewed 4731 times

[Rip76]

Headed to CRP for work, till Thurs...

Will report.

[srainhoutx]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1236 PM CDT TUE JUN 5 2012

.AVIATION...
SLOWING OUTFLOW FROM ROUGHLY COLUMBUS-IAH-GOODRICH WILL CREEP SWD
IN THE NEXT COUPLE HOURS ABOUT THE SAME TIME SEABREEZE WILL
DEVELOP AND MOVE NORTH. MAY SEE SOME ISO/SCT STORMS DEVELOP AS
THEY COME TOGETHER. CONVECTIVE TEMP IN THE LOW-MID 90S AND CU
DEVELOPING ELSEWHERE SO CAN`T RULE OUT SOME ISOLATED ACTIVITY
ELSEWHERE...BUT SUSPECT BETTER COVERAGE WILL BE E OF HWY 59 WHERE
BEST MOISTURE SITUATED. WILL PROBABLY SEE A BREAK THIS EVENING
BUT WILL NEED TO WATCH FOR SOME ADDITIONAL STORMS TO DEVELOP TO
OUR N OVERNIGHT AND POSSIBLE EDGE INTO NRN PARTS OF SE TX. MODELS
ARE SHOWING GOOD SHRA/TSTM COVERAGE ALONG/N OF I-10 WED AFTN.

[srainhoutx]

Interesting update from the HPC Diagnostic Discussion. Basically they are tossing the Euro and NAM solutions for now...as expected, this a low confidence forecast...

...UPPER LOW ORIGINATING OVER THE TEXAS PANHANDLE...

PREFERENCE: GFS/UKMET
CONFIDENCE: BELOW AVERAGE

NAM MOVES TO THE SOUTHERN EDGE OF GUIDANCE ENVELOPE...DROPPING
MORE ENERGY AND THE PRIMARY 500 MB CENTER TO THE LOWER RIO GRANDE
VALLEY/NORTHWESTERN GULF OF MEXICO MORE QUICKLY THAN THE GFS/ECMWF
WHICH MAINTAIN A LOW CENTER CLOSER TO THE RED RIVER INTO FRIDAY
BEFORE THE GFS SINKS TO THE SOUTH AS WELL...LEAVING THE ECMWF A
MORE NORTHERLY OUTLIER. WHILE THE NAM IS A STRONGER OUTLIER...THE
ECMWF IS A WEAK OUTLIER WITH THE UPPER HIGH BUILDING OVER THE
SOUTHWESTERN U.S./NORTHWESTERN MEXICO WHICH SHOULD HELP PULL THIS
FEATURE TO THE SOUTH LATER IN THE PERIOD. THE ECMWF ALSO SHOWS
EVIDENCE OF GRIDSCALE FEEDBACK WHICH MAY BE FURTHER ENFORCING ITS
MORE NORTHERLY POSITION.

[srainhoutx]

The 12Z GFS Ensembles continued the trend to a 'wetter forecast'...

[weatherguy425]

Dew points are mixing out more than I expected today, especially Hobby northward. Hopefully moisture can really start to move in from the SSW.

[redneckweather]

Won't see any convection in the area today. Maybe tomorrow....maybe.

[weatherguy425]

HPC has trimmed back totals and GFS is becoming a little more consistent with keeping the low and associated heaviest rains in north Texas, still hoping for at least seabreeze convection the next few days.

[Ptarmigan]

I think it could be a rainy week.

[Ptarmigan]

CU field continues to develop along the left over boundary. 12Z soundings from Corpus also suggest the cap has fully eroded and it is also interesting to note a bit of mid/low circulation offshore in Gulf in a very shear environment...

06052012 16Z TX VIS latest.jpg

06052012 TC Formation Real Time 12Z gexyrfpr.png

That feature is rather interesting. If conditions were right, something tropical could form..........

[srainhoutx]

The 00Z guidance offer little help in how the next several days will unfold. Early this morning there is little agreement and as mentioned over the past several days, this will be a complex and complicated forecast at best. What we do know is the sagging back door frontal boundary located near NE Texas will be a 'bigger player' as well as meso features that models have an extremely difficult time determining. That said the air mass continues to destabilize as pw's increase and left over outflow boundaries abound. Rain chances still look to be in the 50-60 % range for Thursday into Friday and rainfall totals daily could be in the 1/2 to 3/4 inch range with isolated totals of 1 inch. Event totals still appear to be in the 2-3 inch range with possible higher totals for those lucky few. This has been and will continue to be a moment by moment forecast challenge and conditions remain favorable for showers/storms to develop into the weekend. We will see.

HPC:

SRN PLAINS...

A COMPACT MID-LEVEL LOW/500MB VORT NEAR THE OK/TX PANHANDLE IS
EXPECTED TO DRIFT EWRD/SEWRD TO SWRN OK OVER THE NEXT 24 HRS. THIS
SLOW PROGRESSION IS DUE TO THE SMALL SCALE SYSTEM BEING TRAPPED
UNDERNEATH A LARGE SCALE UPPER RIDGE BASED OVER THE SRN PLAINS.
CONSTANT SERLY FLOW FROM THE WRN GULF IS PRODUCING DEEP MOISTURE
POOLING WITH AOA 1.5 TO 2 INCH PWS... MAINLY SOUTH AND EAST OF THE
CIRCULATION. THE OPERATIONAL AND SREF MODELS ARE SHOWING ACTUAL
MINIMAL SPREAD WITH THE LOW AND LIKELY HVY RAINFALL BUT MDT SPREAD
WITH PLACEMENT/LOCATION OF THE QPF. HPC FOLLOWED A GENERAL BLEND
OF THE OPERATIONAL ECMWF WITH THE LATEST SREF MEAN AND INTERNAL
PSEUDO BIAS CORRECTED GUIDANCE FOR QPF AND WITH THE LIGHT STEERING
FLOW IN PLACE... EXPECT SLOW MOVEMENT AND/OR TRAINING OF CELLS TO
OCCUR. EXPECT POSSIBLE AREAL AVG AMOUNTS OF 1 TO 2 INCHES ACROSS
SWRN OK INTO NORTH/CENTRAL TX WITH LOCALLY ISOLATED 3 INCH AMOUNTS
IN THE MORE ORGANIZED ACTIVITY DUE TO THE IMPRESSIVE MOISTURE
CONTENT.

EXCESSIVE RAINFALL DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
249 AM EDT WED JUN 06 2012

...VALID 06Z WED JUN 06 2012 - 12Z THU JUN 07 2012...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...



TX/OK...

A COMPACT MID-LEVEL LOW/500MB VORT NEAR THE OK/TX PANHANDLE IS
EXPECTED TO DRIFT EWRD/SEWRD TO SWRN OK OVER THE NEXT 24 HRS. THIS
SLOW PROGRESSION IS DUE TO THE SMALL SCALE SYSTEM BEING TRAPPED
UNDERNEATH A LARGE SCALE UPPER RIDGE BASED OVER THE SRN PLAINS.
CONSTANT SERLY FLOW FROM THE WRN GULF IS PRODUCING DEEP MOISTURE
POOLING WITH AOA 1.5 TO 2 INCH PWS... MAINLY SOUTH AND EAST OF THE
CIRCULATION. THE OPERATIONAL AND SREF MODELS ARE SHOWING ACTUAL
MINIMAL SPREAD WITH THE LOW AND LIKELY HVY RAINFALL BUT MDT SPREAD
WITH THE EXACT PLACEMENT/LOCATION OF THE QPF. HPC FOLLOWED A
GENERAL BLEND OF THE OPERATIONAL ECMWF WITH THE LATEST SREF MEAN
AND INTERNAL PSEUDO BIAS CORRECTED GUIDANCE FOR QPF AND WITH THE
LIGHT STEERING FLOW IN PLACE... EXPECT SLOW MOVEMENT AND/OR
TRAINING OF CELLS TO
OCCUR. EXPECT POSSIBLE 1 TO 2 INCH AMOUNTS ACROSS SWRN OK INTO
NORTH/CENTRAL TX WITH LOCALLY ISOLATED 3 INCH AMOUNTS IN THE MORE
ORGANIZED ACTIVITY DUE TO THE IMPRESSIVE MOISTURE CONTENT. IN THE
SHORT TERM... ORGANIZED ACTIVITY SOUTH OF THE CIRCULATION EARLY
THIS MORNING COULD PRODUCE LOCALLY 1 TO 2 INCH/HRLY AMOUNTS... AS
GUIDANCE IS HANDLING THIS POORLY BY EITHER BEING DISPLACED TO THE
NORTH OR EAST. THIS IS A PERFECT EXAMPLE OF A LOW CONFIDENCE FCST
AND REASON JUST BEHIND ISSUING A SEE TEXT THAN ACTUAL AREA FOR
EXCESSIVE RAIN.

[srainhoutx]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1216 AM CDT WED JUN 06 2012

VALID 061200Z - 071200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS NERN CO...SERN WY...AND
WRN NEB...

...SYNOPSIS...
A MEAN UPPER TROUGH WILL REMAIN OVER THE WRN STATES...WITH A DEEP
LEAD WAVE EJECTING NEWD OUT OF MT AND INTO CANADA. BEHIND THIS
FEATURE...ANOTHER SHORTWAVE TROUGH WILL MOVE ACROSS THE FOUR CORNERS
AREA BY 00Z. TO THE E...A LARGER BUT WEAKER TROUGH WILL REMAIN E OF
THE MS RIVER...WITH A BELT OF 50-60 KT MIDLEVEL FLOW FROM THE UPPER
MS VALLEY SEWD INTO THE CAROLINAS AT 00Z.

AT THE SURFACE...LOW PRESSURE WILL DEEPEN OVER ERN CO AND WILL BE A
FOCUS FOR SEVERE STORMS. A WEAK FRONT WILL SETTLE SWD ALONG THE
CNTRL GULF COAST AND INTO NRN FL...WITH MORE ISOLATED SEVERE STORMS
HERE.

...SERN WY...NERN CO...WRN NEB...
A SURFACE TROUGH WILL DEEPEN DURING THE DAY FROM ERN CO INTO THE
CNTRL DAKOTAS...WITH SELY SURFACE WINDS BRINGING DEWPOINTS NEAR 50
INTO NERN CO. WITH AROUND 30 KT MIDLEVEL FLOW...HODOGRAPHS WILL BE
FAVORABLE FOR SUPERCELLS. VERY STEEP LOW TO UPPER LEVEL LAPSE RATES
WILL BE IN PLACE WITH SEVERE THUNDERSTORMS LIKELY BY
AFTERNOON...FORMING IN THE DENVER AREA. LARGE HAIL WILL BE
LIKELY...AND DAMAGING WINDS WILL BECOME INCREASINGLY LIKELY AS CELLS
PRODUCE OUTFLOW WITH MERGERS. LITTLE IF ANY CAPPING WILL EXIST EVEN
DURING THE EVENING...WITH STORMS LIKELY TO PERSIST.

...SRN HIGH PLAINS...
SELY FLOW AROUND THE SURFACE HIGH OVER THE GREAT LAKES WILL HELP
BRING LOW LEVEL MOISTURE WWD INTO SERN CO...ERN NM...AND WRN TX.
STRONG HEATING WILL RESULT IN SOME MIXING...BUT AN AXIS OF
INSTABILITY WILL BE PRESENT OVER CO/NM. WITH A WEAK UPPER LOW OVER
NW TX/WRN OK...AND THE BASE OF AN UPPER TROUGH ACROSS THE CNTRL AND
NRN ROCKIES...ELY SFC WINDS VEERING TO WLY AT AROUND 20 KT AT 500 MB
WILL RESULT IN MARGINALLY FAVORABLE SHEAR FOR A FEW SUPERCELLS GIVEN
THE LAPSE RATES AND INSTABILITY IN PLACE. HAIL IS LIKELY...ALONG
WITH LOCALLY GUSTY WINDS.

...SERN TX...LA...
AN AREA OF STRONG INSTABILITY IS FORECAST TO DEVELOP FROM ERN TX
INTO LA....WHERE BOUNDARY LAYER DEWPOINTS WILL BE IN THE UPPER 60S
TO NEAR 70 F. FORECAST SOUNDINGS INDICATE WEAK SHEAR PROFILES WITH
NO LARGE SCALE SUPPORT FOR FORCING BUT SFC CONVERGENCE NEAR THE
BOUNDARY SHOULD BE ENOUGH FOR AT LEAST ISOLATED STRONG TO SEVERE
STORMS BY AFTERNOON CAPABLE OF HAIL OR WIND.

...SRN GA...NRN FL...
A BELT OF STRONGER MIDLEVEL FLOW IS FORECAST TO LIFT NWD DURING THE
DAY...WHICH WILL WEAKEN DEEP LAYER SHEAR PROFILES AND FLOW AS
COMPARED TO PREVIOUS DAYS. A ZONE OF INSTABILITY WILL EXIST NEAR THE
SURFACE BOUNDARY WHICH WILL LIE ALONG THE CNTRL GULF COAST INTO NRN
FL AND SRN GA. DAYTIME HEATING AND WEAK CONVERGENCE WILL RESULT IN
SCATTERED THUNDERSTORMS. A FEW MAY BE STRONG WITH MARGINAL WIND OR
HAIL...BUT THE OVERALL SEVERE THREAT APPEARS LOW DUE TO MINIMAL
SHEAR AND POOR MIDLEVEL LAPSE RATES.

..JEWELL/LEITMAN.. 06/06/2012

[srainhoutx]

Morning e-mail from Jeff:

Wetter pattern will begin to transpire today across the area.



Well defined upper level low over NW TX is sparking widespread thunderstorms this morning while a weak southwestward moving frontal boundary over NE TX and W LA is producing a few showers. Surprisingly nothing over the Gulf waters with all the deep moisture in place. The NW TX upper level low will remain nearly stationery today and have little influence on our weather, while the frontal boundary over W LA slowly settles WSW into east TX and possibly as far SW as our NE counties (around the Livingston area). Expect this boundary to be the focus for early afternoon thunderstorm development as trigger temperatures in the upper 80’s are reached. Gusty outflow winds are possible with these storms and the overall steering pattern is toward the SSW so the storms and their outflow will move deeper into the area and likely collide at some point with the northward moving seabreeze. Overall feel the best chances will be along and NE of a line from College Station to Katy to Galveston.



Factors appear to be slightly more favorable for thunderstorms on Thursday with the NW TX upper level low moving closer to the area and moisture reaching its peak along with the diffuse frontal boundary in the area. Thunderstorms should develop by late morning and continue through the afternoon hours on Thursday. Slow storm motions and focusing boundaries could produce excessive short term rainfall amounts, but lack of favorable low level inflow should make these cases isolated and keep storm organization loose.



Upper level low will open into an elongated trough over the region Friday with the trough axis pushing east of the area by Saturday. Deep moisture will linger across the region on Friday and expect another day of good rainfall coverage. Rain chances look to start to lower over the weekend as the trough moves eastward and ridging builds into the area from Mexico. Feel it is best to retain at least 30% for both Saturday and Sunday and many times deep tropical moisture is hard to dislodge.



Rainfall amounts for today-Saturday will average .5-1.5 inches across the area with isolated amounts of 2-4 inches possible. A few locations could see greater totals especially just north of our region where the upper level circulation will track and meso models are showing more organized storms with very heavy rainfall.

[srainhoutx]

Perhaps a Slight Risk later today for areas N and E of Houston?. We will see...

[srainhoutx]

The 12Z WRF/NMM continues to advertise heavy rainfall S of the mid/upper low meandering SE across TX/OK. It is interesting to note that this meso model continues to suggest a transition to a warm core disturbance and does drop the sheared trough axis S into the Gulf over time. As always, none of the guidance is doing a good job handling this feature as well as the sagging frontal boundary across NE TX/N LA, so caution is advised...

[ticka1]

I guess my hopes is that this will not be a total bust and we get some rain. If we don't garden and yard will be extremely dry.

[Portastorm]

I guess my hopes is that this will not be a total bust and we get some rain. If we don't garden and yard will be extremely dry.

I'm with you on that ... everything looked so promising just 24 hours ago. Oh well, as srain points out, most of the guidance has been clueless so perhaps there will be a pleasant surprise for those of us south/southeast of Waco.

[redneckweather]

I'm just not seeing it either. I suspect we will get some isolated seabreeze t-storms over the next few days...some will get lucky and some won't. It's 90 degrees here on the north side and not a shower in sight.