2012 SE TX/SW LA Weather:Cold/cool week.

[Jagno]

Looking ahead at the next week it appears that "stripping" season is upon us. It starts out cool enough in the mornings to have a jacket and pants and throughout the day you end up stripping off layers. LOL

We have not had any measurable rain in the past week but I am hoping we'll get some gentle soaking showers this weekend at least.

[vbhoutex]

Still waiting on our promised rain, which is sslloowwllyy approaching from the West, unless you are in the North metro area where they have been getting some storms or at least it looks like heavy rain on radar. Most local ocm are talking about possible ff, but I am not convinced of that happening yet based on the current radar. We've have about 1.5" this week so we don't need heavy rains, but good soaking rains are almost always welcomed.

edit at 9:23pm-Have had at least an inch of rain so far this afternoon and evening. I would expect more based on radar but my area is in a lull for the time being.

[Jagno]

VB, we haven't had a single drop of rainfall. Local met was calling for 50% today and 80% tonight.....................and not even a mist.

[vbhoutex]

Still waiting on our promised rain, which is sslloowwllyy approaching from the West, unless you are in the North metro area where they have been getting some storms or at least it looks like heavy rain on radar. Most local ocm are talking about possible ff, but I am not convinced of that happening yet based on the current radar. We've have about 1.5" this week so we don't need heavy rains, but good soaking rains are almost always welcomed.

edit at 9:23pm-Have had at least an inch of rain so far this afternoon and evening. I would expect more based on radar but my area is in a lull for the time being.

Reporting 1.35" as of 8 am this morning with light rain still falling.

[vbhoutex]

I would like to order a continual dose of the current weather in Houston!!! Is there a waiter available??
Absolutely loving this with lows around 60f and highs in the 80s without a cloud in the sky!!

[PTrackerLA]

57 degrees here this morning which makes that the coolest morning since April 24th! My favorite months of the year have now started...we made it guys!

[vbhoutex]

Jeff thinks we're going to get wet.

Change on the Horizon‏

After over a week of nice fall weather, changes are on the way.

High pressure aloft over the region and ridging SW from the eastern US has kept a fairly dry and warm air mass in place for the past several days. However high pressure at the surface is moving eastward and low pressure is developing in the lee of the Rockies ahead of a slow moving upper level trough over the SW US. This is resulting in an increase in the southerly flow and slight increase in surface moisture. At the same time powerful Hurricane Miriam is moving NW off the western coast of MX under the influence of ridging over N MX and the developing trough over the SW US. High level moisture plume is clearly noted extending NE from the circulation of Miriam spreading ENE to NE into central MX and toward the TX border.

Parameters are slowly coming together for a period of very wet weather Fri-Sun as the upper trough over the SW US interacts with eastern Pacific hurricane Miriam. The overall setup will likely produce an excessive rainfall event for some location across the state of TX late this week/this weekend. Current upper level trough will slow with lift reaching TX by late this week, while both Gulf and mid/high level moisture increase across the area as Miriam sheds moisture and energy NE. PWS increase toward 1.5 inches on Thursday and 2.0 inches by late Friday and then into the 2.0-2.4 inch range on Saturday with soundings becoming increasingly saturated. Upper level jet dynamics come into play by Friday as a 250mb jet streak is progged over NC TX increasing large scale lift over C and SE TX. Expect to see scattered showers and thunderstorms develop and move inland along the TX coast with more organized rainfall over C and N TX on Friday. With moisture levels running very high expect areas of very heavy rainfall.

Upper trough and moisture plume from Miriam sag eastward over the weekend with SE TX coming increasingly under the influence of both the lifting by the trough aloft and high level moisture/energy from the tropical system. Expect more widespread and organized rainfall potential Saturday into Sunday. With moisture levels in the “excessive” range heavy rainfall is likely, but at this time there is no well defined surface boundary to focus/anchor convection at least not at the present time. One would think that with upstream convection some sort of outflow boundary could/would be present on the following days and this potential will need to be watched.

Since we are still over 48 hours from the onset of any event, there is plenty of time to fine tune and nail down the location that looks most favorable for heavy rainfall. Only recently have model guidance come into decent agreement on the phasing of the moisture of Miriam and the upper level trough so some additional changes are likely.

[vbhoutex]

Jeff still thinks we're going to get wet:

Increasingly Wet‏

Widespread rainfall event increasingly likely this weekend

Ingredients continue to come together for a period of wet weather from Friday-Sunday. Moisture is returning to SE TX this morning as noted by the isolated inland moving showers on radar over the coastal waters into the coastal and inland first tier counties. These showers appear to be in response to a sliver of higher moisture being transported northward on increased southerly flow of the past 48 hours. With a little heating this morning expected a continuation of these showers today.

Of more importance is the late week period into the weekend as parameters are coming together to produce a potential widespread rainfall event. Low pressure formation ahead of a deepening SW US trough will help transports low level tropical moisture over the southern Gulf of Mexico northward into the region starting Thursday. May see slightly better rain chances on Thursday than currently being indicated, but the better chances should hold off until Friday when the tropical moisture reaches the area. Expect numerous showers and thunderstorms on Friday pulling northward off the western Gulf of Mexico. At the same time, mid and high level moisture is already spreading NE across MX into TX from EPAC tropical system Miriam. This moisture along with the increasing Gulf moisture will become entrained in the slow moving trough producing widespread rainfall from SW TX into E TX over the weekend.

Surface frontal boundary currently over NW TX will only slowly drag SE over the next 2 days and gradually enter the area early Saturday…more importantly this boundary adds a focus for deep convection that was largely absent yesterday in the model guidance. This change does raise some concern for more significant rainfall over the weekend as the slow moving trough, a slow moving surface boundary, saturated air column, and extremely high moisture levels (PWS 2.2-2.4 inches) all combine to produce some very heavy rainfall. Still not overly confident on where the heavy rains will set up although the southern half of TX appears to be in the best location south of the 250mb jet streak and near/south of the surface boundary. The “tropical like” air column will support some very heavy rainfall rates in a short period of time and this will need to be watched especially if any cell training or slow storm motions are noted. Would not at all be surprised to see some 2-3 inch per hour rainfall rates with this set up. Models are really keying in on Saturday afternoon-Sunday morning as the best time for organized heavy rainfall spreading from SW to NE across the region.

[CajunMama]

Home football game Saturday. Nice and sunny all week. Saturday's forecast? 70% chance of rain during the day and 60% that night.

[vbhoutex]

Excessive rainfall this weekend? Here's Jeff's take on it.

Active weather period expected Friday-Sunday.

Upper level storm system over the western US will move slowly eastward into TX over the next 48-72 hours. High pressure aloft will be pushed southward and at the surface eastward allowing a more favorable influx of both Gulf and Pacific moisture and lowering heights aloft. General subsidence will be replaced with general lift as the upper trough and impulses rotating around the trough move into the state. Increasing moisture today will likely cause a few streamer showers west of I-45 and south of I-10 similar to yesterday. Rain chances begin to creep upward on Friday as surface high shifts eastward allowing the pool of deep tropical moisture over the southern Gulf of Mexico to surge northward. At the same time mid and high level moisture from weakening tropical system Miriam will move across TX from the SW. With the air column becoming increasingly saturated and hard to time or ill defined disturbances approaching from the SW by midday Friday expect showers and thunderstorms to begin to develop and overspread the region from the Gulf waters. Coverage should be on the lower side for most of Friday, but where it rains it will be heavy.

Main event looks to be Saturday into Saturday night as the main upper trough ejects into SW TX and forces surface low pressure formation over SW TX. GFS/ECMWF/NAM model all generally agree on the development of thunderstorms over SW TX late Friday night/early Saturday in a region of strong lift ahead of the upper trough which then moves eastward across SC TX on Saturday. GFS and NAM QPF bullseyes suggest some sort of MCS feature may develop and track ESE toward the middle TX coastal plain by Saturday evening. Air mass ahead of the upper trough and surface low completely saturates with PWS pushing 2.3 inches and favorable low level inflow. The extreme moisture levels (pushing 2 std above early October normals) combined with slow moving organized thunderstorms raises flash flooding red flags. Given the saturated air column warm rainfall production will be likely with little dry air entrainment leading to excessive short term rainfall rates. Tropical like MCS systems tend to slow in the overnight hours some especially as they near the TX coastal plains where the low level inflow increases after dark and this raises the threat for extended heavy rainfall into Sunday morning.

Both models agree that the best lift and rainfall will be focused south of I-10 and west of I-45 or toward the coastal bend into our SW counties where the models are showing the greatest QPF. While the models are in agreement on this placement, that does not mean that is where the threat will be greatest and it is possible that more of the area could be under the gun Saturday night for excessive rainfall. Will likely not be able to firm the threat area up any more than broadly prior to Saturday morning. Widespread rainfall amounts of 2-3 inches are likely with isolated amounts of 4-5 inches especially over those SW counties. Given the moisture profiles I would not be surprised to see a few locations pick up a quick 6-8 inches but these should be fairly small is spatial coverage…hopefully. Grounds are generally dry over much of the area and will be able to handle much of this rainfall, but urban areas will respond quickly to the high short term rates and some flooding or ponding is likely where rainfall rates exceed 1.5 inches in less than 30 minutes. While widespread rains are likely, most rivers are at or below base flow levels, so there is plenty of capacity to handle the expected amounts of run-off.

[vbhoutex]

Now looking like a possible Flash Flood event for SE TX per Jeff:

Widespread heavy rainfall becoming increasingly likely.

Parameters continue to come together from midday Friday-Sunday to produce widespread heavy rainfall across the region. Slow moving upper level trough over the SW US will begin to spread large scale lift into TX over the next 6-12 hours with surface low pressure forming over the SW Rio Grande plains near/around Laredo. Tremendous tropical moisture advection off the western Gulf of Mexico will surge PWS into the 2.0-2.4 in range by late today with mid and high level moisture arriving from the west from the remains of EPAC hurricane Miriam. Surface low will move ENE across the area on Saturday/early Sunday with widespread thunderstorms.

Flash Flood Threat:

With the air column becoming increasingly saturated over the next 12 hours rainfall production will become more tropical like with excessive short term rainfall rates likely. Moisture levels rise to near 2 standard deviations above late September averages and this combined with the potential for cell training and organized slow moving storms really raises the threat for flash flooding. While grounds are fairly dry and flash flood guidance is high, short term rainfall rates of 2-4 inches per hour will be possible given the setup and air mass capabilities and the threat for training or slowing storm motions could extend such a rainfall rate over a period of time. Urban areas will be at greatest risk from the short term excessive rainfall rates likely leading to street flooding and ponding. While most rivers are at base flow or below total rainfall amounts over the weekend will likely produce significant rises.

Widespread amounts of 2-4 inches appear likely with isolated totals of 3-6 inches and I would not at all be surprises to see some locations with totals in the 8-10 inch range (these bigger totals) should be fairly isolated. Similar set ups in the past (October 1998) and (October 2002) have produce some incredible short term rainfall amounts especially over SC TX. Still too early to attempt to determine where the greatest risk area will be, but areas along and south of I-10 will have the best moisture.

A Flash Flood Watch will likely be require for portions or all of SE TX later today.

[PTrackerLA]

I did not realize we were in for so much rain until I saw this latest graphic from our NWS. Could be some flooding issues around the area.

[vbhoutex]

We are already getting showers in W. Houston. Nothing of heavy variety yet.

...FLASH FLOOD WATCH IN EFFECT FROM SATURDAY MORNING THROUGH SUNDAY
MORNING...

THE NATIONAL WEATHER SERVICE IN HOUSTON/GALVESTON HAS ISSUED A

* FLASH FLOOD WATCH FOR A PORTION OF SOUTHEAST TEXAS...INCLUDING
THE FOLLOWING COUNTIES...AUSTIN...BRAZORIA...BRAZOS...
BURLESON...CHAMBERS...COLORADO...FORT BEND...GALVESTON...
GRIMES...HARRIS...HOUSTON...JACKSON...LIBERTY...MADISON...
MATAGORDA...MONTGOMERY...POLK...SAN JACINTO...TRINITY...
WALKER...WALLER...WASHINGTON AND WHARTON.

* FROM SATURDAY MORNING THROUGH SUNDAY MORNING

* A STORM SYSTEM WILL DEVELOP AND MOVE ACROSS THE STATE OVER THE
WEEKEND. DEEP TROPICAL MOISTURE WILL ACCOMPANY THIS STORM AND
WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL THAT COULD
LEAD TO FLASH FLOODING ACROSS PORTIONS OF SOUTHEAST TEXAS.
RAINFALL TOTALS FOR THE EVENT ARE EXPECTED TO AVERAGE 1 TO 2
INCHES WITH ISOLATED AMOUNTS EASILY REACHING AT LEAST 2 TO 4
INCHES. EVEN HIGHER AMOUNTS ARE POSSIBLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.
IF ANY FLOODING IS OBSERVED...DO NOT ATTEMPT TO DRIVE THROUGH THE
WATER. REMEMBER...TURN AROUND DON'T DROWN!

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

[vbhoutex]

Flash Flood Watch cancelled for our area. The low has tracked further North than originally predicted so the heavier rains should stay to our North. So far today we have had 0.53" at my house. Don't expect a whole lot more unless we have something form to our SW which isn't currently progged.

[BigB0882]

Yeah, we had a very cloudy and drizzly couple of days but the rain was not at all what I expected. I don't know if we even got an inch of rain total and that one graphic had BTR in the 5 inch zone.

[vbhoutex]

Yesterday was cloudy and drizzly here too. Total of 0.01" yesterday. I think the 2 day total was 1.34", which I am not complaining about because we really needed it.
Today is GEORGEOUS. It is 80f and not a cloud around.

[Jagno]

I've been utilizing this beautiful weather to decrapify my 4 stall garage. It's beginning to get pretty warm again but I'm looking forward to the new front that is supposed to be in our area over the weekend again to cool us back down.

[vbhoutex]

According to one Houston station we will get as low as 48f on Sunday with highs only in the 60's Sunday and Monday. The other 2 mainstream stations are calling for 50's to 70's. All of it sounds great to me, but we have to get through more possible 90f readings tomorrow and Friday to get there.

[vbhoutex]

Did someone forget to tell the weather this is mid-October?? Currently 90f and freaking downright uncomfortable outside!! UGH!!! Where did Fall go?

[Tireman4]

Gosh it was a torture chamber for my run. Man oh man. I got the 7 miles in, but I swear, I do hate running sometimes....Saturday should be another beauty...Sigh...