July: Hot & Humid To End The Month

[srainhoutx]

HGX issues Severe Thunderstorm Warning for Harris County

[biggerbyte]

Porter got hardly anything. It was coming, then just like every day the past several days, it split. It stormed north and south of here. It has been east and west of here. Does that mean that Sunday is bulls eye day?? LOL!

[jasons2k]

Same story here. I have some light rain/sprinkles here, but most of it skipped me. It looked so good and then, poof! I'm hopeful tomorrow will be better....

[MontgomeryCoWx]

Got .8 inches of rain in east Conroe

[SusieinLP]

Clouds and thunder in La Porte but again, nothing.....Close but no cigar.

[Katdaddy]

No rain down here in League City. Nice view of the cell that went poof earlier over Houston.

[ticka1]

It is thundering like crazy here between baytown and mont belvieu - but no rain yet. Radar is very active on the east side of Houston - so with any luck I hope to see some rain today!

[weatherguy425]

While there isn't much sun to destabilize the atmosphere this morning, convective temps are obviously low enough for storms to fire judging by the current radar. Need to watch any outflows spit out by the complex on the east-side to see if they can fire heavier rains further west. Already seeing some small, but stronger showers developing over Harris County moving quickly north and east.

[jasons2k]

The Trinity River corridor from Chambers County up to Liberty is just getting slammed with heavy rain - I would look out for flooding in that region. You can see the shortwave axis in the radar just to our east, slowly drifting west and almost stationary. Looks like a wet pattern ahead, for sure.

[srainhoutx]

Folks to the W of where the morning showers/storms are currently firing may need to keep a close eye on future heavier storm development as the afternoon wears on. We've had some breaks in the clouds up here in NW Harris County and a bit more destabilization may be in order with PW's running in the 2.2 to 2.4 range. The pattern looks favorable for heavier storms to drop 2 inch+ rainfall rates where they form.

[srainhoutx]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1047 AM CDT SUN JUL 8 2012

TXC201-081745-
/O.NEW.KHGX.FA.Y.0065.120708T1547Z-120708T1745Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
HARRIS TX-
1047 AM CDT SUN JUL 8 2012

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

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

* UNTIL 1245 PM CDT

* AT 1036 AM CDT...DOPPLER RADAR INDICATES A PERSISTENT AREA OF
SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST HARRIS COUNTY THAT
CONTINUES TO REDEVELOP IN THE SAME AREA. RADAR AND AUTOMATED RAIN
GAUGES SHOW RAINFALL RATES UP TO 2 INCHES PER HOUR AT TIMES. THIS
MAY CAUSE SOME MINOR STREET AND FEEDER ROAD FLOODING.

* SOME LOCATIONS THAT WILL EXPERIENCE MINOR FLOODING INCLUDE
PASADENA...BAYTOWN...LA PORTE...CHANNELVIEW...DEER PARK...
CLOVERLEAF...GALENA PARK...JACINTO CITY...HIGHLANDS...TAYLOR LAKE
VILLAGE...SHOREACRES AND MORGAN`S POINT.

[srainhoutx]

So far through the 12Z suite of computer guidance less the Euro, all indications point to a very wet pattern ahead for most if not all the upcoming week. The only model that seems to not be handling things very well is the NAM (WRF/NMM) as that model opens up the mid/upper low and shears it out while the rest of the global guidance keep a closed circulation drifting slowly W. The frontal boundary appears to be a focal point for multi day heavy rainfall events and even some suggestion of nocturnal core rains possible Tuesday into Thursday as the boundary sags just N of the Houston Metro. There are some impressive multi day rainfall totals as well being suggested by guidance. Some of the models are ‘hinting’ at isolated totals nearing the 10 inch mark. We will see about that. What is becoming clear is this pattern will likely linger and very well could set the stage for a potential Flood event before all is said and done. Again, we’ll monitor the situation and keep that umbrella handy.

HPC:

...BREAK IN THE SUBTROPICAL RIDGE NEAR THE WESTERN GULF COAST...
PREFERENCE: NON 12Z NAM COMPROMISE
CONFIDENCE: AVERAGE

THE BIGGEST NOTICEABLE DIFFERENCE WITH THIS FEATURE IS WITH THE
UPR LEVEL / 250 MB REFLECTION OF A CLOSED LOW IN THE ERN GULF OF
MEXICO. THE 12Z NAM IS ON ITS OWN OPENING UP THIS LOW INTO A
TROUGH AXIS AS IT TRACKS WESTWARD...WHILE THE REMAINING AVAILABLE
GUIDANCE KEEPS THE UPPER LOW AS A CLOSED LOW. THE 12Z NAM IS ALSO
SHOWS GREATER SEPARATION IN THE 500 RIDGE ACROSS THE CNTRL GULF
COAST BY WED EVENING / 00Z/12. THE 12Z UKMET/CMC SHOW THE
BEGINNING OF A POSSIBLE EVOLUTION TOWARD A SINGLE CLOSED MID LEVEL
CENTER BY THE END OF THE SHORT RANGE...00Z/12...AND DUE TO
UNCERTAINTIES OF THE PATTERN BETWEEN THE WRN RIDGE AND ATLANTIC
RIDGE...WILL RECOMMEND A NON-NAM COMPROMISE THROUGH 00Z/12.

[jasons2k]

There are some nice storms west of I-45 and I'm glad to see most folks are getting some decent rains. Unfortunately for me, the outflow that moved-in from the south is cutting the legs off the precip as it moves east and approaches I-45. I sorta got caught between this morning's rain to the E/SE and the new stuff to the W/NW. The sun has been peeking through so maybe there is some hope for later on.

[djjordan]

Not too much going on at my house today. We did get some light thundershowers .... (meaning more thunder ...very light rain on and off) throughout the day. With this pattern however, I am sure my lawn will be happy this week.

[srainhoutx]

Today through Wednesday appear to provide the best chances for scattered showers/storms across the Eastern half of the Lone Star State on E into Louisiana. Currently a shear axis/trough extends from near Matagorda Bay on NNE into the ArkLaTex Region where a closed mid/upper circulation resides and has been meandering slowly W. Showers/storms are increasing along the Coastal Waters of SE TX on E to Vermillion Bay and off to our W for inland areas. The latest HPC QPF forecasts suggest 3-4 inches of rainfall may be possible the next couple of days. Heavier storms will be slow moving and could drop 2-3 inch per hour rainfall rates. By Tuesday, a slowly sagging S frontal boundary should be S of the Red River Valley as the heat ridge migrates W into the Great Basin. A weakness continues in the mid to upper levels across Central/East Texas as a weak frontal boundary sags S of the Red River Valley. A light N flow aloft behind that boundary develops with an onshore flow to the S across Coastal SE Texas/SW Louisiana providing a focal point for a heavy rainfall potential. The forecast remains rather complex and complicated as guidance offers different solutions on just when that ArkLaTex disturbance will be picked up and shunted off to the E. The prudent call appears to keep at least isolated storm chances going into Thursday and Friday before rain chances decrease and the ridge slowly builds back E toward the Central Plains.

[srainhoutx]

Morning e-mail from Jeff:

Active pattern of showers and thunderstorms will continue for the entire week.



The large heat ridge that has brought the record breaking temperatures to the Midwest and eastern US has moved westward and is now centered over the four corners region with the other ridge centered off the US mid Atlantic coast. In between these two high pressure cells aloft, a height field weakness (trough), has developed over the SE US into the southern plains. Tropical moisture has infiltrated the area from the east over the weekend with PWS values on average of 1.8-2.1 inches across the region with the highest values confined to the areas along and east of I-45 and over western LA. This deeply tropical-like air mass combined with general weak large scale lift from the upper trough aloft, weak upper level disturbances traversing the area, and modest daytime heating will produce numerous showers and thunderstorms today-Thursday. Weak northerly steering flow from the four corners ridge will help slowly move convection toward the S and SW, but the mean flow is weak and storm motions will be slow (less than 10mph).



Radar already has numerous areas of moderate rainfall with embedded heavier showers over the region. Suspect with only a few hours of heating this morning, additional and stronger storms will begin to develop (around 1000am). Combination of an uncapped tropical air mass and numerous outflow boundary collisions will support continued development well into the afternoon hours before the air mass becomes “worked over” and stabilizes.



Little to no change in the upper level pattern will keep high rain chances for July standards in place through the week…and very possibly well into next week. Tue-Thurs will feature a weak and diffuse frontal boundary moving into the area from the NNE and this will only add an additional focus for thunderstorm development. The boundary may help to serve as a mechanism to drive more organized storms which could enhance a flash flooding threat compared to the current state of hit and miss type storms. Will need to keep a close eye on the potential for organized convection near/along this boundary and especially during the early morning hours when a weak low level jet over the western Gulf would enhance moisture transport and sustained excessive rainfall rates.



Frontal boundary washes out, but tropical moisture and weakness aloft remains overhead into next weekend. Think activity will return to the more scattered seabreeze variety during the afternoon hours versus the current tropical-like trends of coastal morning development and late morning/early afternoon inland development. Brief riding may attempt to gain some ground from the west in the Friday time period, but doubt this will cut rain chances below 30%. Models are in some agreement and the entire pattern wanting to repeat itself by late next weekend into the following week with high rain chances possibly remaining in the forecast through the middle of July.



Rainfall Totals:

With the tropical air mass in place, excessive rainfall will be likely under the stronger cells. A HCFCD rainfall gage yesterday recorded 3.36 inches of rainfall in a little over an hour and these types of rainfall rates will be common where strong cells develop or any training forms. Totals through the end of the week will average 2-3 inches with isolated amounts up to 5 inches. Totals may need to be pushed up some especially over the north and northeastern areas if more organized storms develop near/along the frontal boundary where several inches in a few hours would be possible.



Note: Cloud cover and rainfall will keep high temperatures below normal for July with highs only in the mid to upper 80’s. The high yesterday for Houston was only 83 compared to 97 last year.

[jasons2k]

Two day total thus far = .13". I hope today is better

Edited: I see more sun for me today, it's already 83F, & no storms or outflows (yet) to contaminate the atmosphere here.

[jasons2k]

Yeah - I see some fresh cells popping to my W and NW towards Lake Conroe. That's where they need to be to move this way later. The only fly in the ointment is the cells to the SW are spitting out an outflow that is racing ahead. I hope that outflow doesn't move up this way and cutoff the warm air ahead of those storms up to my W/NW. It almost drives one crazy having to monitor every minor detail as one thing can mess the whole thing up.

There does appear to be some sort of disturbance/ripple with those storms to the west moving in - it looks like they are trying to consolidate into a line...

[weatherguy425]

Yeah, shear/trough axis is definitely making its presence known in western Louisiana this morning. Earlier convection in that area appears to have also put out an outflow boundary which is slowly moving west and helping to fire additional storms in our southeastern counties. At the same time there appears to be a boundary near Sugarland moving northeast and another in western Harris and Montgomery counties moving due east (Also noticing some showers developing ahead of these near the west loop.. While outflow boundaries can stabilize the atmosphere and limit convective growth, they can also encourage storms to form as well as air rapidly is forced upwards during boundary collisions. Also, today we've had a lot more sun, ;likely leading to more surface instability to work with. I feel that our odds of some heavier rains over a significant area of real estate are still looking good.

[Andrew]

Really coming down in NW harris. A lot of outflow boundaries are really helping.