SE TX/SW LA weather: Much cooler and WET after Tuesday

[Extremeweatherguy]

wow! What a nice surprise this morning! The forecast low last night was 63˚..but we ended up much cooler than that. I am currently sitting at 56˚ right now in Spring, which is my coolest reading of the season thus far.

update: I am now down to 54.9˚.

[cctxhurricanewatcher]

First strong cold front for Texas usually means Tropical Storm/Hurricane season cancel for us!

Let's hope the theory holds up!

[jasons2k]

From Jeff Lindner - tool cold for me this early, oh well

First strong cold front of the fall season forecast to arrive on Monday.

AM temps. range from 56 at Tomball to 72 at Port Lavaca this morning as dry air mass has settled over the region allowing radiational cooling toward the dewpoint. Dry and fair weather will rule through late Saturday before the change to more unsettled weather by Sunday.

Long wave trough entering the Pacific NW this morning will evolve into deep trough over the western US by Sunday. In response surface flow over the western Gulf and TX will return to the SE with pool of deep tropical moisture ready to surge inland. Feel the moisture surge will be rapid with showers and a few thunderstorms possible by Sunday afternoon as Caribbean moisture is advected into the region.

Early Next Week:

Models have come into much better agreement with the GFS being about ½ right and the ECMWF being about ½ right yesterday. Both now agree that a strong front will cross the state on Monday and that the upper trough will cut-off from the main flow and park over the southern plains for much of next week.

Will tackle the frontal push first: Air mass should be moist and unstable by late Sunday with showers and thunderstorms streaming northward off the Gulf. Strong frontal forcing early to midday Monday should produce a line of thunderstorms along and behind the front. GFS 1035-1040mb surface high bridges the Rockies and drops into the plains ushering in a much colder air mass. Expect frontal passage from early Monday to Monday evening across the area with high temps. being before the front and temps. falling rapidly in the post frontal strong cold air advection.

Onset of cold air advection will be very strong with NAM and GFS showing 925mb winds out of the NW at 40-50kts late Monday into Tuesday. Will likely see sustained surface winds of 20-30mph inland and 25-35mph along the coast. As cold air strikes and spreads across the still warm Gulf of Mexico will likely see winds gust to over gale force. Small craft advisories are a given…and offshore gale warnings may be needed. Inland wind advisories and lake wind advisories will likely be needed.

With the upper trough forecast to cut-off over OK and sit and spin for much of next week, mid to upper level SW flow will upglide over the cold dome at the surface (isentropic lift pattern…overrunning). Clouds and a chance of rain may linger much of next week in the post frontal air mass making conditions damp and cool. We will see if in fact the trough cuts-off as forecast as the GFS 500mb height anomaly over the southern plains for the middle of next week is nearing -21dm.

As for temps. a drop of 10-15 degrees is likely with the frontal passage on Monday. Continued cold air advection and post frontal showers will help lower temps. even more. If the clouds linger highs on Tuesday and Wednesday are much too warm as the models are showing a 10-15 degree diurnal range. For now will show temps. falling into the 60’s Monday afternoon and into the low to mid 50’s by Tuesday morning. For Tuesday, highs in the upper 60’s look possible, but if clouds linger highs near 60 would be more likely. Strong NW winds will make it feel much colder as we have become very accustom to the high temps. and humidity of the last 6 months.

[Yankeegirl]

I cant wait till the cold air filters in... bring it on!!

[PTrackerLA]

Still waiting to break out the jacket, could it happen next week?

It's always great to see summer finally fade away around here by late October and that appears to be starting to happen. A month from now we'll be talking about the first frost coming up, bring it on!

[Extremeweatherguy]

12am Temperatures...

IAH - 62˚
Hooks - 59˚
Conroe - 55˚
Hobby - 65˚
Sugar Land - 60˚
Galveston - 73˚

My thermometer - 58.3˚

[Extremeweatherguy]

6am temperatures...

IAH - 58˚
Hooks - 55˚
Conroe - 52˚
Hobby - 59˚
Sugar Land - 57˚
Galveston - 72˚

My thermometer - 54.3˚

[Extremeweatherguy]

The forecast for the next week is one of the nicest we have seen in months...

This Afternoon: Sunny, with a high near 87. South wind between 5 and 10 mph.

Tonight: Clear, with a low around 63. South wind between 5 and 10 mph.

Sunday: Mostly sunny, with a high near 86. South wind between 5 and 15 mph.

Sunday Night: A 30 percent chance of showers and thunderstorms, mainly after 1am. Partly cloudy, with a low around 67. South wind 5 to 10 mph becoming northeast.

Monday: Showers and thunderstorms likely. Mostly cloudy, with a high near 67. North wind 5 to 10 mph increasing to between 15 and 20 mph. Winds could gust as high as 25 mph. Chance of precipitation is 60%.

Monday Night: Partly cloudy, with a low around 52.

Tuesday: Mostly sunny, with a high near 71.

Tuesday Night: Mostly clear, with a low around 49.

Wednesday: Mostly sunny, with a high near 75.

Wednesday Night: Mostly clear, with a low around 49.

Thursday: Mostly sunny, with a high near 75.

Thursday Night: Mostly clear, with a low around 49.

Friday: Mostly sunny, with a high near 76.

[vbhoutex]

I will believe that forecast when I actually see it happen. I hope it does because it is time for fall to start!!!!!

[Yankeegirl]

OK, so when is the good weather going to start? I want some storms then cooler weather!!! ((please??))

[Extremeweatherguy]

OK, so when is the good weather going to start? I want some storms then cooler weather!!! ((please??))

It all will begin tomorrow. Here is the last forecast from the NWS for Monday...

Monday: Showers and thunderstorms likely, mainly before 1pm. Mostly cloudy, with a temperature falling to around 58 by 5pm. Calm wind becoming northwest between 15 and 20 mph. Winds could gust as high as 25 mph. Chance of precipitation is 60%.

Monday Night: Partly cloudy, with a low around 49. North wind between 10 and 15 mph, with gusts as high as 20 mph.

[jasons2k]

Latest from Jeff Lindner:

Long awaited strong cold front will arrive early Monday ending our Indian summer.

Discussion:

Strong frontal boundary diving SSE across NW TX late this afternoon with cold temps. following (Amarillo currently 52 with NW winds gusting over 30mph). Powerful upper trough digging across the southern Rockies will eject into the plains late tonight with rapid increase in dynamical lifting over the area. Strong low level jet will crank up after sunset pumping good Gulf moisture northward. Will likely see sustained winds ramp up into the 15-25mph range out of the south across the coastal bend after dark as a well defined low level jet flows northward into a deepening plains cyclone. Strong frontal forcing, increasing upper dynamics, and moisture return all point to rain chances along and behind the front. Dynamics and best moisture are not lining up so severe is not expected.

Front should reach CLL by 600am, IAH by 900am and GLS before noon. Highs temps. will be early with a good 10-15 degree fall with the frontal passage and continued temp fall through the afternoon with strong cold air advection. Post frontal clouds will be slow to clear and a chance of light rain will linger into Monday evening as temps. fall into the 50’s.

Strong NW winds will onset with frontal passage. NAM and GFS continue to show impressive 925mb winds of 40-50kts over the area Monday. Will likely need inland and coastal wind advisory and offshore gale warnings have been posted from Matagorda Bay offshore. Will likely see gust at or above gale force across the inland bays with offshore platforms likely gusting over 50mph into Monday night as the cold air strikes the warm Gulf promoting steep low level lapse rates.

Extended:

Models continue to disagree with cutting off of the upper low over the SC plains Monday through the end of the week. There is little agreement among the models so for now will go with clearing skies Monday night and cool clear conditions through the rest of the week with the area under N flow aloft. Should the upper low cut off more to the W than expected will need to cut highs and introduce clouds and threat of light rain into the forecast Tuesday and Wednesday.

Aviation/Marine:

Big problems in both sectors over the next 24 hours as powerful cold front sweeps the region. Impressive pressure rises will induce strong offshore winds with good low level winds shear at all terminals. Forecasted 925mb winds of 40kts+ will make for a rough ride landing aircraft on E/W runways. Surface winds of 25-35mph with gust to 40mph will be possible especially at GLS and CLL. Same wind speeds will be felt at DFW, SAT, and AUS so some disruption in air travel can be expected Monday.

Very hazardous marine conditions will develop as front moves offshore. Expect gale conditions outer waters with high end small craft adv/low end gale warning conditions across the bays. Sustained surface speeds of 25-35mph with gust of 40-45mph across the bays and nearshore waters. Offshore sustained winds of 30-40mph with gust to 50mph especially east of Rockport and S of Matagorda Island. Seas will build to 10-12 feet offshore by Monday evening and 6-7 feet in the bays. Strong offshore flow will drive water out of the bays and tides will run 1-2 feet below normal by Tuesday morning. Inland lakes will see sustained speeds of 25-35mph Monday afternoon with gust to 40mph especially at Conroe and Somerville.

Metro Houston forecast:

Tonight: mostly cloudy with a 30% chance of showers after midnight, Lows near 70. South winds 10-15mph.

Monday: cloudy with a 60% chance of showers and thunderstorms. Highs in the mid 70’s early then falling into the lower 60’s and upper 50’s by late afternoon. S winds 10mph will shift to the NW and increase 25-35mph and gusty.

Monday night: clearing skies late and windy. Lows near 50. NW winds 15-25mph and gusty.

Tuesday: mostly sunny with highs in the upper 60’s. NNE winds 10-15mph.

[Extremeweatherguy]

The front is showing up nicely on radar:

[JenBayles]

Pretty radar pic you found Extreme.

OK, I notice Jeff and the HGX boyz all say there isn't much moisture for this front to work with. Can someone explain how that translates to a 60% chance of rain? Also, there seems to be plenty of moisture already coming into our area from Kiko, so where does the "no moisture" come from? (I have a declining mind and want to know...)

[jeff]

Pretty radar pic you found Extreme.

OK, I notice Jeff and the HGX boyz all say there isn't much moisture for this front to work with. Can someone explain how that translates to a 60% chance of rain? Also, there seems to be plenty of moisture already coming into our area from Kiko, so where does the "no moisture" come from? (I have a declining mind and want to know...)

There is moisture...both in the mid/high levels from Kiko and the low levels from the onshore flow. Problem is that the favorable lift is lagging the surface front and so the "best" moisture will be shunted eastward along and ahead of the front. There is also some capping in the mid levels which will surpress the favroabel frontal forcing to a line of showers. Scattered showers will develop behind the front as the upper trough moves through the region Monday PM. Gvein the upstream temps this evening over W OK and far TX pand. there is some pretty cold air heading southward and very strong NW winds. 12Z NAM showing upper low retrograding toward mid week into N TX....may end up more cloudy and cooler than current forecast shows...we shall see.

[JenBayles]

Thanks Jeff! I appreciate you taking the time to explain to the uneducated.

[Extremeweatherguy]

Here is a pretty notable temperature drop behind this front...

Sweetwater, TX
-88˚ at 6:05pm and 64˚ at 7:25pm. (A drop of 24˚ in just 80 minutes! )

[Aquawind]

Here is a pretty notable temperature drop behind this front...

Sweetwater, TX
-88˚ at 6:05pm and 64˚ at 7:25pm. (A drop of 24˚ in just 80 minutes! )

That is impressive if without rain.

[JenBayles]

Wow! EWG - you checked out that map you posted earlier? It's lightin' up purty darn good!

[Extremeweatherguy]

Wow! EWG - you checked out that map you posted earlier? It's lightin' up purty darn good!

yeah, and what is interesting is that most of the heavy precipitation is forming behind the front. I would expect the same to occur here too, and that is why we could end up seeing a wet, cold afternoon tomorrow even after the front has moved well past our area. With the strong winds and temperatures in the 50s, it might even feel a little bit like winter (in October).