August 2016: Rain Chances Continue.

General Weather Discussions and Analysis

Re: August 2016: Significant Pattern Change/Rain Chances Ret

Postby jasons » Fri Aug 12, 2016 11:09 am

From the morning NWS-AFD - shows just how lucky those folks are who saw some rain the last few weeks - most of us continue to toast:

.Climate...

Rainfall totals so far for August are...
-College Station - trace
-Houston Intercontinental Airport - 0.00
-Houston Hobby - trace
-Galveston - trace
Last Measurable Rainfall: September 26
jasons
 
Posts: 2037
Joined: Thu Feb 04, 2010 1:54 pm
Location: Imperial Oaks

Re: August 2016: Significant Pattern Change/Rain Chances Ret

Postby srainhoutx » Fri Aug 12, 2016 11:23 am

The 12Z GFS suggests a very complicated and difficult forecast is likely regarding where the heaviest rain may fall and which neighborhoods could see the highest totals. Let me point out that the NWS Houston/Galveston Forecasters fully understand the challenges ahead and that folks are getting anxious because of what they are seeing unfolding just a short 300 miles to our East in Lafayette and Baton Rogue. Please understand that our Professional Forecasters DO feel pressure to "get it right", so let's be mindful that they are our neighbors and those of us that are weather savoy understand that weather forecasting is not an exact science. Also know that some of us personally know these Professional Forecasters in real life and that they are big supporters of our efforts here in the KHOU Weather Forum. We are fortunate to have so many folks that are paid to forecast the weather supporting and following what we do here, and for that we ALL can be proud.

08122016 12Z 54 gfs_z700_vort_scus_10.png


08122016 12Z 54 gfs_z850_vort_scus_10.png


08122016 12Z 54 gfs_z500_vort_scus_10.png


08122016 12Z GFS 108 qpf_acc_us_sc.png
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

Member: National Weather Association
Facebook.com/TxWeatherBoard
Twitter @TxWeatherBoard
User avatar
srainhoutx
Site Admin
Site Admin
 
Posts: 17875
Joined: Tue Feb 02, 2010 3:32 pm
Location: NW Houston FM 1960/SH 6

Re: August 2016: Significant Pattern Change/Rain Chances Ret

Postby BlueJay » Fri Aug 12, 2016 11:43 am

Sure looks promising! We are toasty up here in the Woods...
BlueJay
 
Posts: 737
Joined: Tue Mar 04, 2014 11:47 am
Location: Alden Bridge-The Woodlands, Texas

Re: August 2016: Significant Pattern Change/Rain Chances Ret

Postby David Paul » Fri Aug 12, 2016 11:44 am

Yep, the GFS has been and continues to be the most aggressive with rain totals for our area this weekend. Regardless of the exact track of the low, PWats will be exceedingly high in SE Texas over the next few days and ANY storm that develops in that atmosphere has the potential to dump 2"+ rain per hour. Will it be exactly on YOUR neighborhood...? No one can tell. Stay close to weather updates this weekend. We'll be watching it here at KHOU11 closely.
David Paul
Pro Met
Pro Met
 
Posts: 41
Joined: Thu Jun 21, 2012 8:27 am

Re: August 2016: Significant Pattern Change/Rain Chances Ret

Postby srainhoutx » Fri Aug 12, 2016 12:40 pm

08122016 mcd0552.gif


MESOSCALE PRECIPITATION DISCUSSION 0552
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
121 PM EDT FRI AUG 12 2016

AREAS AFFECTED...CENTRAL/SOUTHERN LA...SOUTHWEST MS

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 121720Z - 122330Z

SUMMARY...DANGEROUS AND LIFE-THREATENING FLASH FLOODING/RUNOFF
FROM EXTREMELY HEAVY RAINFALL WILL CONTINUE THROUGH THIS AFTERNOON.

DISCUSSION...VERY INTENSE CONVECTIVE RAINFALL CONTINUES AROUND THE
SOUTHWEST FLANK OF A LOW TO MID LEVEL LOW CENTER OVER SOUTHWEST MS
WHICH CONTINUES TO SLOWLY DRIFT WEST. CLOUD TOPS HAVE WARMED EVER
SO SLIGHTLY OVER THE LAST COUPLE OF HOURS AS SEEN IN 1-MINUTE
GOES-14 IR ANIMATIONS...BUT CLOUD TOPS ARE STILL ABOUT -75C FROM
FAR SOUTHWEST MS INTO SOUTH-CENTRAL LA WHERE PROLIFIC RAINFALL HAS
BEEN OCCURRING THROUGHOUT THE MORNING HOURS.

THE CONVECTION REMAINS HIGHLY PERSISTENT WHILE FOCUSING WITHIN A
VERY MOIST/UNSTABLE AND CONFLUENT LOW LEVEL FLOW REGIME. PWATS ARE
VERY HIGH AND NEAR ALL-TIME RECORD LEVELS CURRENTLY OVER CENTRAL
AND SOUTHERN LA AS INDICATED BY THE 12Z LIX RAOB WHICH HAD A 2.78
INCH PW OF RECORD. LOW PRESSURE AT LEAST IN THE 850/500 MB LAYER
HAS BEEN SHOWING EVIDENCE OF STRENGTHENING THIS MORNING WHICH IS
HELPING TO FURTHER CONCENTRATE AND ORGANIZE THE CONVECTION WHILE
ALSO ENHANCING THE CONFLUENT LOW LEVEL FLOW AROUND THE SOUTHWEST
FLANK OF THE LOW CENTER.

THE 16Z HRRR/HRRRP GUIDANCE INDICATES THE POTENTIAL FOR AN
ADDITIONAL 4 TO 8 INCHES OF RAIN...WITH ISOLATED HEAVIER AMOUNTS
THROUGH LATE-AFTERNOON ACROSS PORTIONS OF CENTRAL AND SOUTHERN LA.
IN SOME CASES...THIS WILL BE ON TOP OF ALREADY EXTREMELY HEAVY
RAINFALL AMOUNTS THAT HAVE OCCURRED. DANGEROUS AND
LIFE-THREATENING FLASH FLOODING/RUNOFF WILL BE LIKELY AS A RESULT.

ORRISON

ATTN...WFO...JAN...LCH...LIX...SHV...
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

Member: National Weather Association
Facebook.com/TxWeatherBoard
Twitter @TxWeatherBoard
User avatar
srainhoutx
Site Admin
Site Admin
 
Posts: 17875
Joined: Tue Feb 02, 2010 3:32 pm
Location: NW Houston FM 1960/SH 6

Re: August 2016: Significant Pattern Change/Rain Chances Ret

Postby unome » Fri Aug 12, 2016 12:56 pm

:cry:


Area Forecast Discussion
National Weather Service Houston/Galveston TX
1246 PM CDT Fri Aug 12 2016

.AVIATION...
Main change to the forecast is to pull mentions of showers and storms - it appears subsidence over our area due to the low over Louisiana will be too strong to allow much in the way of convection. While it may not be totally dry, any showers that manage to pop up will be few and far between, if one will be over any site, it's impossible to say with confidence. Otherwise, should look for MVFR cigs over the usual suspects again tonight. End of period may start to be influenced by encroaching rainfall from Gulf low, but will leave fleshing out the specifics to future
cycles.
unome
 
Posts: 2403
Joined: Fri Feb 12, 2010 7:11 pm
Location: Cypress

Re: August 2016: Significant Pattern Change/Rain Chances Ret

Postby houstonia » Fri Aug 12, 2016 1:03 pm

Inconceivable! :x :x

unome wrote::cry:

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1246 PM CDT Fri Aug 12 2016

.AVIATION...
Main change to the forecast is to pull mentions of showers and storms - it appears subsidence over our area due to the low over Louisiana will be too strong to allow much in the way of convection. While it may not be totally dry, any showers that manage to pop up will be few and far between, if one will be over any site, it's impossible to say with confidence. Otherwise, should look for MVFR cigs over the usual suspects again tonight. End of period may start to be influenced by encroaching rainfall from Gulf low, but will leave fleshing out the specifics to future
cycles.
houstonia
 
Posts: 138
Joined: Sun Jun 14, 2015 6:51 pm
Location: Houston, Texas (Southwest side; Sharpstown)

Re: August 2016: Significant Pattern Change/Rain Chances Ret

Postby Rip76 » Fri Aug 12, 2016 1:09 pm

Puts sprinklers back out.
User avatar
Rip76
 
Posts: 967
Joined: Mon Feb 15, 2010 1:38 am

Re: August 2016: Significant Pattern Change/Rain Chances Ret

Postby srainhoutx » Fri Aug 12, 2016 1:29 pm

ECMWF is somewhat similar in tracking the 850mb Vort, but a tad NW of the GFS. Will need to watch things very closely beginning tomorrow and continuing throughout Sunday into early Monday.
Attachments
08122016 12Z 72 ecmwf_uv850_vort_scus_4.png
08122016 12Z 72 ecmwf_T850_scus_4.png
08122016 12Z Euro f72.gif
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

Member: National Weather Association
Facebook.com/TxWeatherBoard
Twitter @TxWeatherBoard
User avatar
srainhoutx
Site Admin
Site Admin
 
Posts: 17875
Joined: Tue Feb 02, 2010 3:32 pm
Location: NW Houston FM 1960/SH 6

Re: August 2016: Significant Pattern Change/Rain Chances Ret

Postby unome » Fri Aug 12, 2016 2:02 pm

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
240 PM EDT Fri Aug 12 2016

Valid 00Z Sat Aug 13 2016 - 00Z Mon Aug 15 2016

...Significant flash flood potential expected to continue for portions of the Gulf Coast and lower Mississippi valley...

...Hot and humid conditions expected to continue into the weekend for much of the East Coast...

An area of low pressure that originated in the tropics will continue to drift slowly west across the lower Mississippi valley through Saturday morning before merging with a frontal system Saturday afternoon. The area of low pressure will continue to focus widespread showers and thunderstorms across the Gulf Coast and lower Mississippi valley through Saturday, with the continued threat of heavy rains over areas that have already received copious amounts of rainfall. The result will be a continued significant flash flooding potential across these areas through Saturday. After the low merges with the frontal boundary Saturday afternoon, the threat of heavy rainfall is expected to expand along the front from Saturday afternoon into Sunday, extending from the southern plains to the Northeast. The most substantial risk of flash flooding on Sunday is forecast to be across portions of the mid-Mississippi valley.

Along the Eastern Seaboard, high pressure at the mid and upper-levels will expand through the weekend, keeping hot and humid conditions in place with only very isolated showers and thunderstorms during the afternoon and evening. High temperatures are forecast to be 5 to 15 degrees above average across much of the eastern U.S. on Saturday and Sunday, with manyareas rising well into the 90s. These temperatures will combine with the high humidity to result in dangerous heat index values. Heat advisories as well as excessive heat watches and warnings have been issued for portions of the Mid-Atlantic and Northeast.

High pressure will also remain place across the West through the weekend, keeping most areas dry with above average temperatures. Afternoon high temperatures are expected to be 5 to 15 degrees above average.

Ryan

Image
unome
 
Posts: 2403
Joined: Fri Feb 12, 2010 7:11 pm
Location: Cypress

PreviousNext

Return to Weather Forum

Who is online

Users browsing this forum: Google [Bot], tireman4 and 1 guest