April 2015: Pleasant Weather To End April

[BlueJay]

April showers bring May flowers.
We shall see...

[Ptarmigan]

April is the cruelest month.
-T.S. Eliot, The Waste Land

April has had many well known disasters and tragic events.
Binghampton Massacre-April 3, 2009 13 Killed
Super Outbreak-April 3-4, 1974 319 Killed
USS Akron Crash-April 4, 1933 73 Killed
Tan Son Nhut C-5 Accident-April 4, 1975 153 Killed
Upper Big Branch Mine Disaster-April 5, 2010 29 Killed
Tupelo–Gainesville Tornado Outbreak-April 5-6, 1936 +436 Killed
Start Of Rwanadan Genocide-April 7, 1994 500,000-1,000,000 Killed
Civil War Ends-April 9, 1865 620,000 Killed
1965 Palm Sunday Tornado Outbreak-April 11–12, 1965 271 Killed
First Shot Fired In American Civil War-April 12, 1861 620,000 Killed
Titanic Disaster-April 14-15,1912 1,500 Killed
Boston Marathon Bombing-April 15, 2013 3 Killed
Texas City Explosion-April 16, 1947 600 Killed
Virginia Tech Massacre-April 16, 2007 32 Killed
West Fertilizer Company Explosion-April 17, 2013 15 Killed
San Francisco Earthquake-April 18, 1906 3,000-6,000 Killed
Waco Inferno-April 19, 1993 78 Killed
Oklahoma City Bombing-April 19, 1995 169 Killed
Ludlow Massacre-April 20, 1914 19-25 Killed
South African Airways Flight 228-April 20, 1968 123 Killed
Columbine Massacre-April 20, 1999 13 Killed
Deepwater Horizon/Macondo Well Disaster-April 20, 2010 11 Killed
Guadalajara Explosions-April 22, 1992 252 Killed
Rhythm Club Fire-April 23, 1940 209 Killed
Dan-Air Flight 1008-April 25, 1980 146 Killed
2011 Super Outbreak-April 25–28, 2011 358 Killed
Uireyong Massacre-April 26-27, 1982 57 Killed
China Airlines Flight 140-April 26, 1994 264 Killed
SS Sultana Explodes-April 27, 1865 1,800 Killed
Port Arthur Massacre-April 28-29, 1996 35 Killed
Tropical Cyclone 02B Makes Landfall On Bangladesh-April 29, 1991 140,000 Killed
Los Angeles Riot-April 29-May 4, 1992 53 Killed

Some of the worst disasters in American and world history occurred in April. Bold denotes weather and natural disaster.

[BlueJay]

I am hopeful that April 2015 will be kind to our earth.

[BlueJay]

Would anyone care to speculate about the Houston vicinity weather conditions for Easter weekend-April 4th and 5th?

[srainhoutx]

Right now it looks like we may have a shot of colder air arriving Easter Weekend. There may be a chance of showers and storms Good Friday into Saturday. But that is too far out to know with any certainty.

[BlueJay]

Thank you srain! As you say, I will stay tuned...

[srainhoutx]

After six months of an almost persistent NW flow aloft that brought cut off slow moving Baja lows, plenty of much need rain and cooler than normal temperatures across our Region, that pattern appears to be changing. The longer range ensemble schemes are suggesting a Western trough and a wide open Western Gulf suggesting that severe weather season may be lurking in the not too distant future. The beginning of this anticipated pattern change arrives near Easter and looks to get going during the first full week of April. If the longer range pattern is correct, we should begin so see bouts of severe weather break out across the Southern Plains into Central and Eastern Texas extending east into Louisiana, Arkansas, Missouri and Tennessee and possibly further E into Dixie Alley. With El Nino underway, it is time to dust off those severe weather plans just in case we need them in the weeks ahead.

[Paul Robison]

After six months of an almost persistent NW flow aloft that brought cut off slow moving Baja lows, plenty of much need rain and cooler than normal temperatures across our Region, that pattern appears to be changing. The longer range ensemble schemes are suggesting a Western trough and a wide open Western Gulf suggesting that severe weather season may be lurking in the not too distant future. The beginning of this anticipated pattern change arrives near Easter and looks to get going during the first full week of April. If the longer range pattern is correct, we should begin so see bouts of severe weather break out across the Southern Plains into Central and Eastern Texas extending east into Louisiana, Arkansas, Missouri and Tennessee and possibly further E into Dixie Alley. With El Nino underway, it is time to dust off those severe weather plans just in case we need them in the weeks ahead.

03292015 00Z Euro Ensemble Mean 240 ecmwf-ens_z500a_namer_11.png

03282015 12Z GEFS 234 gfs-ens_z500a_namer_40.png

How do severe wx prospects look for the Tuesday-Friday time period next week, srainhoutex?

[srainhoutx]

Morning briefing from Jeff:

Very nice spring weather will continue today although with an increase in cloud cover and humidity ahead of a storm system expected to cross the region on Wednesday.

Moisture return off the Gulf of Mexico will be shallow with dry air aloft remaining in place and this may impact rain chances overall on Wednesday. An upper level system currently off the California coast will move into TX late Tuesday and across the region on Wednesday. Low to mid level ridging will not break down until late Tuesday suggesting good moisture return does not take place until that time. System appears to weaken as it moves across the state and think the end result will be scattered showers and thunderstorms instead of widespread rainfall.

Upper level ridging builds into the area from old Mexico Wednesday evening-Friday with warm and dry conditions expected ahead of yet another cold front which looks like it may make next weekend a bit of a mess. Front should move off the coast late Friday with overrunning moisture developing behind the boundary over the weekend. Temperatures Friday in the mid to upper 80’s cool into the 60’s over the weekend with cloudy skies and periods of rain. Still plenty of time for things to change for next weekend, but the current forecast will carry overcast and cool with periods of showers and thunderstorms.

[Katdaddy]

Active weather on the way across the Central Plains beginning tomorrow through Thursday. Its that time of year. The severe threat looks to remain to the N and NE of SE TX however rain and thunderstorm chance increase to morrow night. Slight rain chances and clouds will likely continue for the Easter weekend.

[jasons2k]

We shouldn't have issues this spring with cold shelf waters, so cross that off the list of convective inhibitors:

http://www.tropicaltidbits.com/analysis ... _atl_1.png

[srainhoutx]

The global guidance continue to advertise a cold front arriving Friday. Showers and thunderstorms appear likely with the frontal passage. Rain chances decrease by Saturday, but there may be some potential of light drizzle and cooler temperatures behind the front. As of now Easter Sunday looks pleasant. A return flow off the Gulf begins Monday as a Ridge of High Pressure builds across the Western Gulf. Temperatures rebound to near normal next week.

[srainhoutx]

Morning briefing from Jeff:

Upper level disturbance will move across the region today with showers and thunderstorms this afternoon and evening. A few of the storms may be on the strong side with gusty winds and small hail. Best chances for organized thunderstorms will be over the NW and W half of the region where moisture return off the Gulf of Mexico has been greatest.

Thursday and most of Friday will feature very warm conditions with highs easily into the mid 80’s and possibly the upper 80’s ahead of a fairly strong cold front that will pass the area late Friday. Air mass ahead of the boundary Friday afternoon will become fairly unstable as temperatures warm into the mid 80’s and expect showers and thunderstorms to develop along the boundary. A few of the storms Friday afternoon may become severe with a large hail and damaging wind threat, but the main severe weather threat appears to be northeast of SE TX.

Weekend:
Forecast models have come into better agreement that a drier and cooler air mass will filter into the region on Saturday and this should reduce rain chances although skies may not fully clear out. Highs will be roughly 15-20 degrees colder on Saturday compared to Friday. A strong short wave trough heads for the region on Sunday with the old frontal boundary lifting northward across the area. Good rain chances are likely starting Saturday night and for most of Sunday and possibly into Monday. Current model guidance and instability parameters do not support a severe weather threat on Sunday, but will need to keep a close watch on this day especially since a warm frontal boundary will be moving across the region.

[Paul Robison]

Morning briefing from Jeff:

Upper level disturbance will move across the region today with showers and thunderstorms this afternoon and evening. A few of the storms may be on the strong side with gusty winds and small hail. Best chances for organized thunderstorms will be over the NW and W half of the region where moisture return off the Gulf of Mexico has been greatest.

Thursday and most of Friday will feature very warm conditions with highs easily into the mid 80’s and possibly the upper 80’s ahead of a fairly strong cold front that will pass the area late Friday. Air mass ahead of the boundary Friday afternoon will become fairly unstable as temperatures warm into the mid 80’s and expect showers and thunderstorms to develop along the boundary. A few of the storms Friday afternoon may become severe with a large hail and damaging wind threat, but the main severe weather threat appears to be northeast of SE TX.

Weekend:
Forecast models have come into better agreement that a drier and cooler air mass will filter into the region on Saturday and this should reduce rain chances although skies may not fully clear out. Highs will be roughly 15-20 degrees colder on Saturday compared to Friday. A strong short wave trough heads for the region on Sunday with the old frontal boundary lifting northward across the area. Good rain chances are likely starting Saturday night and for most of Sunday and possibly into Monday. Current model guidance and instability parameters do not support a severe weather threat on Sunday, but will need to keep a close watch on this day especially since a warm frontal boundary will be moving across the region.

1. From HGX:


MODELS CONTINUE TO BE FAIRLY CONSISTENT WITH THE NEXT FRONTAL
PASSAGE COMING LATE FRI. THE MAIN DIFFERENCES WILL BE EXPECTED
RAINFALL WITH THE FRONT. THE GFS/ECMWF LOOK TO BE A BIT MORE ON
THE WET SIDE THAN THE NAM FOR THE 12Z RUNS. UPPER LEVEL SUPPORT
LOOKS RATHER WEAK BUT STILL A FAIRLY STRONG FRONT FOR EARLY APRIL.
MODEL SOUNDING SHOW SOME CAPPING TO OVERCOME BUT EXPECT
FRONTOGENTIC LIFT TO BE SUFFICIENT FOR THUNDERSTORM DEVELOPMENT.
INSTABILITY WILL BE LIMITED AND COMBINED WITH CAPPING/DRY AIR
ABOVE 700MB...NOT LOOKING FOR MUCH ACTIVITY TO DEVELOP. SUSPECT
THERE WILL BE A THIN LINE OF SHOWERS AND EMBEDDED THUNDERSTORMS TO
PUSH THROUGH WITH THE FRONT. RAINFALL AMOUNTS LOOK TO BE AROUND A
TENTH TO A QUARTER INCH.

2. Basically, you're saying that any severe storms that do develop will do so North of I-10. Right, Srainhoutex?

[Katdaddy]

SPC has an enhanced risk for the Ozarks and Lower OH Valley today and another enhanced risk area for the TN Valley and portions of MS, AR, and LA on Friday.

The significant severe weather threat will remain to the NE of SE TX Friday however a marginal risk area will extend SW from ETX, across SE, S Central, Central, and STX.

Partly cloud and warm today and Friday with a 20-30% of chance of thunderstorms, some of which could be strong, Friday evening associated with a cold front. Saturday looks to be much colder with highs in the upper 60s but no rain chances Rain chances return with the cold front pushing back N as a warm front Saturday night and Easter Sunday.

[Paul Robison]

SPC has an enhanced risk for the Ozarks and Lower OH Valley today and another enhanced risk area for the TN Valley and portions of MS, AR, and LA on Friday.

The significant severe weather threat will remain to the NE of SE TX Friday however a marginal risk area will extend SW from ETX, across SE, S Central, Central, and STX.

Partly cloud and warm today and Friday with a 20-30% of chance of thunderstorms, some of which could be strong, Friday evening associated with a cold front. Saturday looks to be much colder with highs in the upper 60s but no rain chances Rain chances return with the cold front pushing back N as a warm front Saturday night and Easter Sunday.

Hi, Katydaddy.
Don't know if this is relevant but here's Beaumont TX hazardous WX outlook.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LAKE CHARLES LA
544 AM CDT THU APR 2 2015


FRIDAY THROUGH WEDNESDAY SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP BY FRIDAY AFTERNOON AND CONTINUE THROUGH FRIDAY NIGHT AS A COLD FRONT MOVES THROUGH THE AREA. A FEW STORMS COULD BECOME STRONG TO SEVERE LATE FRIDAY AFTERNOON AND EVENING MAINLY NORTH OF A KOUNTZE (in SE TX, to the NE of Houston) TO MELVILLE (in Central LA) LINE...WITH DAMAGING WINDS AND LARGE HAIL THE PRIMARY THREATS. STORMS WILL ALSO BE CAPABLE OF PRODUCING FREQUENT CLOUD TO GROUND LIGHTNING AND MODERATE TO HEAVY RAIN.


I think what I put in bold explains why the SPC put SE TX is under a marginal risk. (Note: TWO STORMS MAY BE STRONG ACROSS CENLA WHERE THE MARGINAL INSTABILITY WILL BE HIGHER)
Storms believed to weaken as they move south.
Accurate enough for everyone?
Please say yes!

[djmike]

Thanks Paul. I'm in Beaumont, so YES! Thank you.

[srainhoutx]

The cold front that crossed the Region certainly has brought in some cooler air. Enjoy it while it lasts!

[Paul Robison]

HGX says:
MODELS CONTINUE TO SUPPORT THUNDERSTORM CHANCES MAINLY NORTH OF THE AREA FROM DFW TO THE ARKLATX. INCLUDED SOME HIGHER 40-50 POPS FOR COLLEGE STATION TO CROCKETT TOMORROW. SOME OF THE HI RES MESOSCALE MODELS BRING IN CONVECTION ACROSS MUCH MORE OF THE AREA SO WILL STILL KEEP SOME 30 POPS IN PLACE AS FAR SOUTH AS THE COAST.

Fact: The model in question is the HRRR. It seems to be showing a pretty strong storm erupting across Houston/Galveston area on Eastern Sunday.

Questions:

1. Is the HRRR usually correct in pinpointing areas where mesoscale events are likely to occur?

2. Are we looking at the possibility of "pulse" storms ( single cell thunderstorms that are usually below severe levels, but still of such substantial intensity to produce severe weather for a brief period of time) erupting across the Houston Metro on Easter Sunday if the HRRR is correct?

[Katdaddy]

...THERE IS A MRGL RISK OF SVR TSTMS A SMALL PART OF SE TX…

The SPC has a marginal risk of severe thunderstorms for inland portions of SE TX along and N of the 59 corridor this afternoon.

...SE TX THIS AFTN...
SATELLITE AND SFC OBSERVATIONS ATTM SHOW LEADING EDGE OF SFC-BASED
MARITIME TROPICAL AIR JUST ENTERING THE MIDDLE TX GULF CST ATTM AS
LOW-LVL WAA/MOISTURE TRANSPORT CONTINUE ALONG SW FRINGE OF
RETREATING COOL AIR DOME ASSOCIATED WITH SERN STATES SFC RIDGE.
CURRENT STREAM LINE AND PRES CHANGE DATA SUGGEST THAT A WEAK WARM
FRONT MAY BE IN THE PROCESS OF FORMING FROM N OF VCT TO N OF HOU TO
NEAR BPT. THIS FEATURE SHOULD DRIFT SLOWLY NWD THROUGH LATER
TODAY....BEFORE BECOMING MORE DIFFUSE AS SLY FLOW OVER E TX
STRENGTHENS EARLY MON.

SFC HEATING WILL BE WEAK AND LARGE-SCALE FORCING FOR ASCENT MINIMAL.
BUT SHALLOW CONVERGENCE/UPLIFT WILL EXIST ALONG THE BOUNDARY...AS
WILL RICH MOISTURE /PW AOA 1.50 INCHES/. AND...WIND PROFILES WILL
FEATURE 40+ KT WLY DEEP SHEAR WITH A SIZABLE LOW-LVL DIRECTIONAL
COMPONENT...ESPECIALLY NEAR FRONT. GIVEN THIS SETUP...A CONDITIONAL
RISK WILL EXIST FOR A STORM OR TWO WITH LOW-LVL ROTATION AND A
NON-ZERO TORNADO THREAT.