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

[JenBayles]

Hoping, praying, crossing fingers and toes for rain not just here in the Houston area, but throughout Texas. This drought is one of the worst I've ever seen, and it's not even Summer yet!

Can someone explain what's happening in layman's terms? Is it a strong La Nina and/or other influences keeping us so dry month after month?

[Ptarmigan]

Hoping, praying, crossing fingers and toes for rain not just here in the Houston area, but throughout Texas. This drought is one of the worst I've ever seen, and it's not even Summer yet!

Can someone explain what's happening in layman's terms? Is it a strong La Nina and/or other influences keeping us so dry month after month?

We are in a La Nina still, but it is weakening. La Nina is what is keeping us dry because it changes the jet stream pattern.

[srainhoutx]

Email from Jeff Lindner - Tuesday 3/10/09:

Big changes will arrive Wednesday as the pattern transitions to cold and wet away from warm and dry.



Large upper trough over the SW US will begin to move eastward into the plains allowing a strong cold front currently over the TX panhandle to drop southward and cross Texas on Wednesday. Upstream air temps. are 14 at Denver and below zero across portions of Montana so some very cold air resides to our NW. Will go with the faster frontal timing as the air mass is cold and dense and little should slow it up. Will show the front through CLL early Wednesday and off the coast by late afternoon. Highs temps. will be pre frontal passage with temps. falling from the 70’s/80’s into the 50’s. We stay cold through much of the upcoming weekend. In fact highs Thursday and Friday may very well remain in the 40’s across our northern counties.



Of bigger importance is the increasing chances for much needed rainfall starting now Wednesday afternoon and continuing into Sunday. Models continue to pound away at some significant QPF values across the state in the heart of the ongoing drought.



Isentropic lift will begin in earnest late Wednesday as the front passes with warm moist southerly flow overrunning the shallow cold dome at the surface. Expect post frontal light to moderate to at times heavy rains to develop in a large band from SW TX through our northern counties Wednesday evening and continue through Thursday. Rainfall amounts of 1-2 inches will be possible along and mainly north of I-10 and really mainly north of HWY 105. SW flow aloft with jet stream disturbances will keep high rain chances going through Friday while off the coast along the old polar boundary a coastal trough and surface reflection form by late Friday.



Rains on Friday should spread southward and over most of the area with amounts of .5 -1.5 inches on top of good rains on Thursday. A strong disturbance will pass over the region Friday afternoon/evening supporting a chance of elevated thunderstorms.



Coastal system cranks up late Friday into Saturday along the lower coast and progresses northward toward Louisiana as a strong short wave rotates across TX on Saturday. Pattern favors extensive rainfall and thunderstorms with good overrunning of the surface cold dome. Will focus this rainfall event closer to the coastal areas (mainly S of I-10) where the best moisture and lift will reside. Could see some hefty totals along the coast as the surface low cranks up. Will good with an additional widespread 1-2 inches Saturday into Sunday, but a few locations may see 3-4 inches in this period especially in our coastal counties.



Rainfall should finally come to an end by late Sunday as a dry NW flow becomes established. Widespread amounts for Wed-Sun should average 2-4 inches with isolated amounts upwards of 4-6 inches. Most favored areas are within the worst drought areas Thursday and Friday and then the coastal areas Saturday and Sunday…although most will see some form of rainfall each day.



Surface low development in the NW Gulf on Saturday will result in increasing NE winds. Such winds are highly conducive of water transport to the coastline and coastal flooding may become an issue Saturday evening especially along Bolivar and the west end of Galveston where dunes were destroyed by Ike. Coastal flood elevations for these locations established prior to Ike no longer hold and coastal flooding may occur with tides running only 2-3 feet above normal especially on Bolivar where so much elevation and sand was lost.

Impressive QPF totals for a drought parched TX over the next 5 days...

[cctxhurricanewatcher]

Nice! We might actually get some rain later this week.

But we've had so many false alarms the last 6 months I feel like Portastorm with Lucy and the football with Austin snow threats from the GFS. When the rain is running down the gutters and forming puddles in streets, I'll believe it. Till then, still praying.

[vbhoutex]

Nice! We might actually get some rain later this week.

But we've had so many false alarms the last 6 months I feel like Portastorm with Lucy and the football with Austin snow threats from the GFS. When the rain is running down the gutters and forming puddles in streets, I'll believe it. Till then, still praying.

I know what you mean!!! Reading Jeff's write up I am somewhat concerned that my area in W. Houston will be in an area between the two heaviest rain threats. We'll see. Any rain is better than none!!

[Tireman4]

Bring on the front. Good Lord my running has been suffering. I mean I swear I cannot finish 7 miles without dying. Get this pollen out of here Mother Nature.

[Ed Mahmoud]

Drought relief, West of the Border, down Mexico way...

[srainhoutx]

Front is along a Longview to just N of College Station to San Antonio line pushing S...

http://www.ral.ucar.edu/weather/surface ... duration=0

Probabaly mid day before reaching DT Houston and to the coast by early afternoon. Don't forget your jackets.


Wednesday morning email from Jeff Lindner:

Strong cold front will usher in unseasonably cold air and good rain chances.



The radar has more color this morning than I have seen in months and this is great news for areas currently experiencing the exceptional drought conditions. Currently a strong polar front extends from NE TX to just N of Austin toward Del Rio. Temp. is 38 at Dallas and 72 at IAH so get ready for that big change in the next 6 hours. Front is barreling southward ahead of schedule as expected and should cross our northern counties by 900am and our central counties by early afternoon. Highs will reach the mid 70’s to near 80 south of the front and then fall into the 50’s and 40’s behind the front. Temps. will then hold nearly steady in the 40’s for the next 3 days under extensive cloud cover, rain, and cold air advection.



We should begin to see some showers develop along the frontal boundary as it crosses SE TX today although the current disturbance over N TX will be lifting off to the NE so besides the front itself there may not be much lift. Models continue to ping away as very high rain chances and good QPF across the state through Saturday. This morning the axis of the heaviest rainfall looks to be focused across our northern zones from Huntsville back WSW toward Austin for the entire event. This is roughly where the 850mb front will stall and act as a trigger for passing disturbances in the noisy SW flow aloft. Will go with scattered rain chances south of I-10 Thursday and widespread N of I-10. A stronger disturbance will approach the region Thursday night into Friday and this should result in good chances across the entire area.



Classic winter coastal troughing event cranks up on Saturday as a potent short wave rotates across the state. Expect the trough along the lower coast to develop/track NE along the coast with good lift over the cold sector in a strongly forced isentropic pattern. We should see good rains for most of the day Saturday (widespread light to moderate rainfall with heavy embedded showers or thunderstorms). As the surface low/trough lifts away Saturday evening we should begin to dry out from west to east with clouds slowly decreasing on Sunday from west to east and sunny skies returning by Monday.



QPF:



Unfortunately will have to focus the highest amounts just north and west of our region…although our northern and northwestern counties should get some very good rains…and very much needed. Will go with 2-4 inches through Saturday along and NW of a line from Livingston to Conroe to Columbus. Expect 1-3 inches along and north of a line from Liberty to Sugar Land to Victoria and generally less than 1 inches along the coast. Coastal areas may not see much rainfall until Saturday as for the next 24 hours the rainfall will be focused more toward the north. The highest rainfall amounts will likely be focused just west and north of the area where rainfall deficits are running close to 20-25 inches in central Texas.



While good rain chances are forecasted and the pattern does favor such…one must remember the magnitude of the ongoing drought and this could play a negative role in getting good rains across certain areas. We will have to see if the pattern is strong enough to overcome the negative feedback processes of the parched ground…we have seen good patterns and rain chances before this winter that resulted in little more than .10 of an inch of rain….so I am somewhat hesitant of what will actually transpire over the next 72-96 hours.

[srainhoutx]

Front passed KCLL. Temp 54* and winds gusting to 45 mph...

http://weather.noaa.gov/weather/current/KCLL.html

May need to edit Topic just a bit.

[JenBayles]

Wow! That's quite a change! Still in the soup here in Bear Creek but it's getting darker...

[Ed Mahmoud]

A thin line of showers, maybe an embedded weak t-shower, on or just behind the front.



More impressive rain behind the front in CenTex

[JenBayles]

Nice to see Central Texas finally getting some rain. My MIL in Wimberley can't remember the last time she saw any water in the Blanco River. Hopefully it'll get trickling again by the weekend and give the wildflowers a needed boost.

[jasons2k]

I can't remember the last time I was so happy to see some rain on the radar!! This will definitely help green things up.

[JenBayles]

Is the line of showers on the radar the cold front itself, or is it a warm front moving up ahead of the system? I've been watching it all morning and it never seems to get any closer to the Bear Creek Dome. Actually seems to be inching ever so slowly north and west. Am I losing my mind - and eyesight?

[cctxhurricanewatcher]

Portastorm is probably outside rolling around in the mud.

[srainhoutx]

Is the line of showers on the radar the cold front itself, or is it a warm front moving up ahead of the system? I've been watching it all morning and it never seems to get any closer to the Bear Creek Dome. Actually seems to be inching ever so slowly north and west. Am I losing my mind - and eyesight?

Rain is behind the shallow cooler airmass as it lifts the warmer/humid air in the upper SW flow. We had FROPa at my location around 11:55 AM and the temp dropped 10 degrees with NW winds to around 12 mph, JenBayles.

[jasons2k]

Hi Jen,

The front stretches from near Bush Airport to Katy and is moving to the SE, approaching the 59 corridor in Metro Houston. The line of showers along the front is broken, advancing to the SE, but individual cells are moving NNE.

The front will move across the Houston area over the next 1-3 hours with scattered shower. Better chances for more widespread rain will be tonight when the next disturbance appraoches.

[JenBayles]

Thanks for the responses jason and srain. I just went outside and the front seems to be seeping in rather than blowing in. Air is noticeably drier and cooler, but no wind to speak of. No rain either - naturally!

[Tireman4]

Slowly but surely, it is coming.

[Ed Mahmoud]

At 1 pm CDT, between Hooks and Interncontinental, or probably right over my house.

80ºF at IAH, 64ºF at DWH.