October 2014: Slight Rain Chances/Halloween Outlook

[Andrew]

Some good totals once again across most of Harris County. Impressive considering many (including myself) didn't think that shortwave would reach this far south.

[Ptarmigan]

The Most Anomalous Cold Spell in Recent History
http://us-climate.blogspot.com/2014/09/ ... ecent.html

October 2000 had a really strong cold blast. It was really anomalous.

[jasons2k]

I had .04"

[Katdaddy]

Isolated sea breeze thunderstorms possible for the next few days with highs near 90F. Perhaps next week another cold front for SE TX.

[Texaspirate11]

Got over an inch and a half of rain yesterday - 10/6
Awesome winds too...

[srainhoutx]

The latest Euro and parallel GFS are slowly coming into agreement with a full latitude trough across the Central US as the AO drops extremely negative by October standards early next week.

[ticka1]

The latest Euro and parallel GFS are slowly coming into agreement with a full latitude trough across the Central US as the AO drops extremely negative by October standards early next week.

In english what does that mean?

[srainhoutx]

The latest Euro and parallel GFS are slowly coming into agreement with a full latitude trough across the Central US as the AO drops extremely negative by October standards early next week.

In english what does that mean?

Likely a strong cold front with severe weather potential ahead and along the frontal boundary with some wrap around moisture associated with the cold core low expected across the Red River Valley and Oklahoma. The 12Z Euro suggests a robust upper low at the base of the trough nearing 3 standard deviations below normal for our Region. The Canadian and UKMet models agree on this very deep Central US trough as well.

[Ptarmigan]

Super Typhoon Vongfong. Looks like Haiyan.



It could impact our weather in a week or two.

[srainhoutx]

The Arctic Oscillation (AO) dropped to a record -4.057 today. It is only the second time since 1950 the AO has dropped to -4 or below in October.

[MESOMAN]

What does that mean srain?

[srainhoutx]

What does that mean srain?

We are seeing signs of a blocking pattern develop where storms systems drop SE from the Gulf of Alaska and a general troughy pattern covers the Inter Mountain West and the Plains. If this blocky pattern persists into the late Fall and Winter, as El Nino develops it tends to suggest much below normal temperatures and above normal precipitation as the Sub Tropical Jet becomes active across Texas. The last episode of an El Nino and an extremely negative Arctic Oscillation was the Winter of 2009-2010 where the earliest snowfall recorded in Houston occurred of December 4th. It is way too soon to speculate on any particular details, but the pattern suggests we may have an interesting weather pattern across the Lone Star State in the days and weeks ahead.

[MESOMAN]

Thanks! I was hoping you would say that!

[srainhoutx]

As High Pressure over the Gulf slides E, showers and storms should increase today across Central and E Texas with the advancing upper low/trough associated with former tropical cyclone Simon. The greatest chances of heavy rain will be across the Southern and Central Plains as a frontal boundary sags slowly S and eventually stalls somewhere near the Austin/Byran/College Station area on E. This boundary along with increasing moisture pooling in the Western Gulf on the W side of the ridge should increase showers/storms coverage Friday into the weekend. The next feature to monitor is the very deep trough moving SE from the Gulf of Alaska this weekend with cyclogenesis or a wrapping up area of low pressure in the mid/upper levels begins across the Panhandle Sunday afternoon and arriving Monday. A squall line looks likely during the daytime hours of Monday as a strong Pacific front sweeps across Texas. Rain chances should finally end late on Monday into Tuesday as a deep cut off cold core low meanders to our E in a blocking regime. If this system (closed upper low) were to slow down and stall a bit closer to E Texas, then rain chances may need to be increased further and the introduction of a heavy rainfall threat may be need late on Sunday into Monday. This a rather complex and complicated forecast with multiple features, so expect day to day fine tuning as the main storm complex in the Gulf of Alaska moves inland across the Pacific NW on Saturday. All forms of severe weather may need to be introduced as well over the weekend for portions of our Region, so check in daily for further updates as this dynamic storm system begins to develop.

[srainhoutx]

Morning Update from Jeff:

Indian summer will continue through the weekend before a strong cold front arrives on Monday.

Warm air advection underway across the NW Gulf coast this morning with good onshore flow and increased dewpoints in the low to mid 70’s. Radar showers a few showers over the Gulf waters and a couple fast moving small showers inland of Matagorda Bay. An upper level storm system was located over southern CA/AZ which has absorbed the remains of EPAC tropical cyclone Simon. Another potent upper level storm was located south of Alaska.

Weather over the next 24-48 hours will be similar to summer with a little more wind but temperatures warming into the 90’s for highs and only falling into the mid 70’s for lows. Enough moisture will be in place for scattered afternoon showers and thunderstorms with some storms capable of producing a couple inches of rainfall…as seen yesterday afternoon over northern Harris County.

Over the weekend (Saturday) a cold front currently over the central plains will move southward and stall somewhere over central TX into SE TX. This boundary will serve to lift the moist and unstable air mass in place resulting in more numerous and organized showers and thunderstorms. Models are not in great agreement on where the front actually stalls and suspect that convection along the boundary will end up pushing it slightly further southward than models suggest anyway. This results in the potential for the boundary to be as far south as US 59 by Saturday evening or as far north as College Station. Point being that showers and thunderstorms will be increasingly likely near this boundary over the weekend.

Sunday-Monday:
Potent upper level storm south of Alaska will move southward and into the W US over the weekend and into the plains early next week. Large scale forcing will result in rapidly deepening surface low pressure Sunday over NW TX/TX panhandle which will quickly return the stalled frontal boundary northward on Sunday. Think rain chances on Sunday will be limited to warm air advection showers in the warm sector with the main frontal boundary lifting north of the region. This type of setup usually results in lower coverage of showers and thunderstorms even though the GFS is showing healthy rain chances on Sunday.

Impressive October cyclone moves into the plains with lots of wind energy and dynamics early next week. Upper level energy will rapidly deepen a surface low pressure system over NW TX with a strong cold front developing on the backside of this surface low. Strong low level forcing along the surging cold front will likely result in rapid thunderstorm development Monday morning NW of our region with a squall line developing and crossing the entire region during the day. Wind energy aloft and dynamics appear to support a severe weather threat on Monday along with some fairly strong gradient winds both ahead and behind the front. Still plenty of time to watch and fine tune the impacts of this system.

[cajun]

Received 4.2" yesterday at the house near Kuykendahl and FM2920 from that late afternoon thunderstorm.....

[BlueJay]

Got home quite late last night to discover some limbs down in the yard and about 0.23 inches per the rain gauge. The sprinklers had the night off.

[srainhoutx]

It appears the conditions addressed above are coming together for an active weather weekend and Columbus Day on Monday. A frontal boundary should push S into Texas and stall tomorrow somewhere S of Austin and could push as far S as Coastal Texas. Over running showers and elevated storms look likely as an area of low pressure develops tomorrow across the Southern Plains and breezy southerly winds pump deep tropical moisture N. The front will retreat back N of Sunday as the deep Western trough S of Alaska approaches. Cyclogenesis begins later on Sunday across the Panhandles of Texas and Oklahoma and a strong Pacific front begins to march SE on Monday. A strong squall line is expected to develop across Texas and all forms of severe weather may be possible early Monday morning across NW Texas and spread S and E during the daytime hours of Monday. A severe weather thread as well as very heavy rainfall should continue marching E into Louisiana Monday afternoon/evening.

[SLM87TX]

what type of pattern is setting up for tomorrow, Saturday? I seen increase POP but what the reasoning for it.

[srainhoutx]

what type of pattern is setting up for tomorrow, Saturday? I seen increase POP but what the reasoning for it.

The frontal boundary moving S across S Central Texas and stalling is the reasoning for increasing rain chances on Saturday. NWS Dallas/Ft Worth has a good graphic of the advancing boundary expected to generate the Saturday wet weather...