October 2015 - Severe Storms/Moderate Risk Excessive Rainfal

[Katdaddy]

Onward to October. Slight rain and thunderstorm chances mainly along the Upper TX Coast today as the area of low pressure just offshore transitions into a trough and moves NE tonight. Any potential tropical cyclone threat is pretty much nil for the Upper TX Coast after Oct 1st. Only 2 tropical cyclones have directly impacted the Upper TX Coast in 135 years after Oct 1st. Even better news, beginning Wednesday and lasting through the weekend will be some beautiful Fall weather so get ready to enjoy.

[srainhoutx]

Morning briefing from Jeff:

Vertically stacked upper level and surface low SE of Galveston this morning will begin to move eastward today with decreasing rain chances across SE TX.

Air mass remains generally moist this morning with dewpoints in the 60’s and once surface temperatures rise into the low to mid 80’s showers and thunderstorms will likely develop on the northwest side of the NW Gulf of Mexico low. Storm motions will be toward the south-southwest and fairly quick. Expecting about 30-40% coverage and this should be the last day of rainfall potential this week.

Of interest is the potential for a decent cool front to arrive into the area Thursday and Friday allowing a very dry air mass to sweep into the region. Models have the front arriving late Thursday into early Friday with weak cold air advection on Friday. NNE winds out or surface high pressure over the Great Lakes will drive a low dewpoint air mass (40’s) into the region. Latest GFS guidance shows a high of only 81 on Friday and lows into the mid 50’s over the weekend. This seems reasonable given the expected dry air mass that will be in place allowing good overnight cooling conditions.

Extended:
Upper air pattern begins to undergo change by early next week as October brings in a more fall like pattern. Potential for a deepening SW US trough through mid week begins to bring Gulf and Pacific moisture into TX with varying solutions as to when and how fast this upper level trough moves into and across TX late next week.

[Cromagnum]

Several things we will need to monitor as we end September and begin October. There are some indications that the sub tropical jet may begin to get rather noisy possibly increasing our rain chances next weekend into the first full week of October. There also are growing indications that the Polar Jet Stream may begin to buckle as the teleconnection indices respond and cooler weather develops East of the Rockies. Another potential fly in the ointment is a landfalling Eastern Pacific tropical cyclone bringing some healthy rainfall chances across Texas during early October. Fingers crossed, we will finally see a real change in the weather pattern that brings moisture back to areas that need it across the Lone Star State.

What does a "noisy sub tropical jet" mean? I've heard the term many times but am unfamiliar.

[redneckweather]

Man, this place is dead! We've got a pretty darn good cool front coming in to give us fall like temperatures through the weekend and no one is excited about it a little? I guess it will take a cat. 4 hurricane coming towards us to get this place picked up a little.

[Ptarmigan]

Man, this place is dead! We've got a pretty darn good cool front coming in to give us fall like temperatures through the weekend and no one is excited about it a little? I guess it will take a cat. 4 hurricane coming towards us to get this place picked up a little.

Joaquin is now a Category 4 hurricane. It has a central pressure of 931 millibars. That is the lowest since Dean in 2007!

[djjordan]

Several things we will need to monitor as we end September and begin October. There are some indications that the sub tropical jet may begin to get rather noisy possibly increasing our rain chances next weekend into the first full week of October. There also are growing indications that the Polar Jet Stream may begin to buckle as the teleconnection indices respond and cooler weather develops East of the Rockies. Another potential fly in the ointment is a landfalling Eastern Pacific tropical cyclone bringing some healthy rainfall chances across Texas during early October. Fingers crossed, we will finally see a real change in the weather pattern that brings moisture back to areas that need it across the Lone Star State.

What does a "noisy sub tropical jet" mean? I've heard the term many times but am unfamiliar.

Basically in a nutshell, A Noisy sub-tropical jet means there are multiple weather systems riding in the Sub Tropical Jet Stream and if they are positioned right for Texas, our boring weather pattern will come to an end with increasing chances for rain.

[srainhoutx]

What an absolutely gorgeous weekend on tap for SE Texas. This is what we live for in our part of the world. Get out and enjoy this cooler and drier weather. Rain may return later next week as a combination of another front and tropical moisture from the Eastern Pacific heads our way.

[DoctorMu]

Dewpoints in the 40s in CLL for the first time in many months - back to April I think.

Joaquin an impressive fish cuisinart as it's doled around the Bahamas long enough for the trough to nudge it north and out to sea.

[jasons2k]

What a beautiful weekend to kickoff October! We could use some rain however - maybe we will get lucky later this week.

FWIW...it won't be another 1,000 years before SC has that much rain again. I just don't put much stock in those statistics.

[djjordan]

Prayers are with the South Carolina flood victims ...... It truly is a historical event that is devastating. We know how floods affect our area, and it truly is amazing to watch what mother nature continues to do even at this hour to South Carolina.

[srainhoutx]

Morning briefing from Jeff:

More humid and warmer conditions to return this week.

US upper air pattern remains mostly blocked with deep low pressure over the SE and SW US and high pressure over the central and southern plains. This has resulted in our locally very nice weather over the last 3 days while the US SE coast has seen some incredible rainfall amounts and flooding (see below). Upper air pattern will slowly begin to unblock as the large scale system over the SE US moves offshore and the SW US system over S CA this morning begins to move eastward over the desert SW. Changes over SE TX will be slow with gradual warming and then slow moistening over the atmosphere as winds turn out of the ESE and SE by mid to late week.

After Wednesday the SW US upper level system will begin to approach TX from the west, but latest guidance is not allowing this system to progress as far eastward as in previous runs and keeps the best dynamics and moisture across western and southwestern TX and mainly W of SE TX. This will focus the heaviest rainfall over west TX with a low level feed of moisture inland over the coastal bend and then WNW to NW into central and W TX. Will go with the highest rain chances over our western and southwestern counties Thursday and Friday (20-30%) with the lowest rain chances over our eastern counties. There is still some uncertainty in this part of the forecast so some changes might be needed toward the end of the week into this weekend.

SC Flooding:
Impressive upper level storm system over the SE US combined with moisture feed from Hurricane Joaquin to produce a period of incredible rainfall over the state of SC this weekend. Additionally, long fetch ENE to E winds resulted in significant coastal flooding and storm surge…some of the highest since Hurricane Hugo (1989). Tides rose to 8.3 ft MLLW at Charleston Harbor on Saturday morning resulting in overwash of the protective seawall and flooding of portions of the city. Inland areas between Charleston and Columbia recorded 15-25 inches of rainfall over the weekend with 10-15 inches falling overnight Saturday into Sunday morning. Rainfall frequency curves for this region indicate between a 500-yr and 1000-yr rainfall amounts.

A few selected rainfall amounts (48-hr storm totals):

3 NE Boone Hall Plantation: 26.88
Gills Creek: 20.28 (16.61 inches in 24 hours)
Millwood: 20.75
Shadowmoss (N Charleston): 23.51
Downtown Charleston: 16.02
Charleston Airport: 17.29

[BiggieSmalls]

Looks like no real fall weather on the horizon in the next two weeks (unless you consider lows in the high 60s and highs around 85 "fall)...The summer that just won't go away....

[Katdaddy]

Increasing high clouds will lead to slight rain and thunderstorm chances by Thursday as the upper level low over the SW US drifts E. The upper level low is forecast to then retrograde back W during the weekend ending the rain chances but increasing heat and humidity.

[Katdaddy]

Partly sunny skies today and Thursday followed by a slight chance of thunderstorms Thursday night through Friday afternoon. A weak cool front arrives Friday night with drier air for the weekend, as well as; slightly lower temps.

[Katdaddy]

A weak disturbance will bring a chance of showers this afternoon through Friday night. A cool front to arrives tomorrow evening and will give SE TX a nice mostly sunny weekend with slightly cooler temps.

[Cromagnum]

Everything about the Houston weather has been bad this year. Feet of rain in the spring followed by 6+ months of summer. I dont think we are actually even going to get a fall this year.

[ticka1]

it will probably go straight to freezing weather when the change does happen.

[sambucol]

it will probably go straight to freezing weather when the change does happen.

I'll take it!!!

[jasons2k]

I don't mind the warm weather, but we could sure use some rain. Even with the spring rains, these mini-droughts we keep having have killed off another round of trees still under stress. It looks like the fall leaves won't have much color this year - they tend to just turn brown and fall off when it's dry like this.

[wxman57]

Here's a meteogram I made off the 6Z GFS. Cold front moves through Tuesday morning but doesn't impact the highs much. A lot drier air by Wednesday and cooler morning lows, though.