April 2016 Recap: Regional Flood/Severe Weather

[ticka1]

What time frame do you think the showers/rain will start around downtown? I am hoping it is after 5:00 p.m.

[srainhoutx]

Morning visible satellite imagery shows several features we need to watch throughout the day. A large Mesoscale Convective System is cross Arkansas this morning with thunderstorms beginning to develop SW of that complex around Shreveport and on SW toward Lufkin. There is a CU field building further to the SW toward the Northern areas of SE Texas that appears to have some potential to back build with daytime heating. The atmosphere appears to destabilizing across our area, but early morning capping issues may continue through at least mid day across our area in SE Texas.

Further West, the dryline is apparent and that area will need to be watched for thunderstorm development this afternoon across the Edwards Plateau and Central Texas. There is a surface low up in the Panhandle where additional storms are firing along the warm from into Oklahoma.

Another are to watch is over Mexico with the sub tropical Jetstream. There is embedded disturbances riding the STJ and could fire storms near Brownsville and Corpus Christi later today. We'll need to monitor the radar trends today and particularly this evening as a disturbance over New Mexico/Arizona provides some lift.

[TexasBreeze]

Quite the concerning discussion this morning....

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1047 AM CDT FRI APR 29 2016

.DISCUSSION... QUICK UPDATE. CAP STILL HOLDING AS OF 10 AM BUT STORMS RAPIDLY DEVELOPING JUST TO THE NORTHEAST OF THE AREA. CU DEVELOPMENT INTO THE NORTHERN COUNTIES MAY BE THE PRECURSOR TO THIS AREA OF DEVELOPMENT EVENTUALLY WORKING BACK DOWN INTO THE CWA AS CAP ERODES THIS AFTERNOON. FORECAST CHANGES INCLUDE LOWERING OF POPS SOUTH WHERE STRONGLY CAPPED AND ADDED HAZY. ACROSS THE NORTH AND WEST FOR THIS AFTERNOON AM EXPECTING RAPID TO EXPLOSIVE DEVELOPMENT BY MID AFTERNOON AND WITH STRONG LOW LEVEL SHEAR AND ABUNDANT INSTABILITY (AWAY FROM THE CAP) WILL HAVE THREATS RANGING FROM TORNADO-WIND-HAIL THREAT IN THE WEST TO HAIL-WIND IN THE NORTHWEST. THIS EVENING THIS WILL SHIFT INTO THE AREA AND FOR WHAT IT IS WORTH THE 12Z NAM PAINTS A GRUESOME PICTURE OF A DANGEROUS SEVERE WEATHER THREAT ACROSS AREAS FROM COLUMBUS TO HUNTSVILLE NORTHWARD. VERY HIGH LOCALIZED HELICITY IN AN ENVIRONMENT OF HIGH INSTABILITY. HEAVY RAINFALL THREAT STILL HIGH AND LATEST HRRR/NAM INDICATING THE WESTERN CWA EARLY THIS EVENING THEN SHIFTING EASTWARD INTO THE REMAINDER OF THE CWA. RAISED POPS NORTH THIS AFTERNOON AND FOR THE HIGHWAY 59 CORRIDOR THIS EVENING AND OVERNIGHT.

[tireman4]

34
FXUS64 KHGX 291742
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1242 PM CDT FRI APR 29 2016

.AVIATION...
29/18Z TAFS HAVE INCREASING CLOUDS THIS AFTERNOON AND GUSTY SOUTH TO
SOUTH-SOUTHEAST WINDS WITH CEILINGS AROUND 2500-3500 FEET. LOOKING
FOR SHRA/TSRA COVERAGE TO INCREASE LATER THIS AFTERNOON AND INTO THIS
EVENING AND ON THROUGH THE OVERNIGHT HOURS. LOTS OF TSRA/VCTS IN THE
OVERNIGHT HOURS (ALONG WITH DECREASING WINDS)...BUT HARD TO PINPOINT
WHERE/WHEN ACTIVITY WILL MOVE EAST OF INDIVIDUAL TAF SITES. TAFS
WILL BE UPDATED AS THIS EVENT UNFOLDS AND EVOLVES. 42

[srainhoutx]

Capping inversion is rapidly eroding N and W of Metro Houston. Thunderstorms are developing along the I-35 Corridor from New Braunfels to just West of Bryan/College Station. Will need to carefully monitor trends throughout the afternoon/evening and overnight hours to see if the cap erodes closer to the Houston Area.

04292016 18Z TX VIS latest.jpg

04292016 ww0124_radar.gif

04292016 mcd0498.gif

MESOSCALE DISCUSSION 0498
NWS STORM PREDICTION CENTER NORMAN OK
1252 PM CDT FRI APR 29 2016

AREAS AFFECTED...NORTHERN AND CENTRAL TX

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 291752Z - 291945Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...NEW THUNDERSTORM DEVELOPMENT IS EXPECTED AS ONE OR MORE
NORTH TO SOUTH ORIENTED BROKEN BANDS ACROSS CENTRAL INTO
NORTH-CENTRAL TX...GENERALLY IN VICINITY AND WEST OF THE I-35
CORRIDOR. ALL SEVERE HAZARDS WILL BE POSSIBLE WITH SEVERE WEATHER
WATCHES LIKELY FOR THIS AFTERNOON INTO THE EVENING.

DISCUSSION...SURFACE AND OBJECTIVE ANALYSES SHOWED RICH
BOUNDARY-LAYER MOISTURE STREAMING TO THE NORTH/NORTHWEST THROUGH
CENTRAL AND NORTHERN TX WITH SURFACE DEW POINTS IN THE LOWER 70S AS
FAR NORTH AS THE DALLAS/FORT WORTH METROPLEX. GOES-14 1-MINUTE
VISIBLE IMAGERY SHOWED CU FORMING AS N-S ORIENTED CLOUD STREETS
ACROSS THE WARM SECTOR...AS SURFACE HEATING BENEATH STEEPENING LAPSE
RATES IS RESULTING IN A VERY UNSTABLE AIR MASS /MLCAPE 2500-3000 J
PER KG/.

MOSAIC RADAR IMAGERY AND LIGHTNING DATA SHOWED ONE STORM HAD
DEVELOPED IN HAYS COUNTY TX...WITH ADDITIONAL CONVECTION BECOMING
DEEPER FARTHER WEST THROUGH NORTHWEST FROM KIMBLE TO ERATH COUNTIES
TX. THIS LATTER CORRIDOR APPEARS TO BE OCCURRING ALONG THE LEADING
EDGE OF STRONGER FORCING FOR ASCENT APPROACHING FROM THE SOUTHERN
HIGH PLAINS SHORTWAVE TROUGH. STRENGTHENING SLY LOW-LEVEL AND SWLY
MID-UPPER LEVEL WINDS WILL RESULT IN DEEP-LAYER SHEAR FAVORABLE FOR
SUPERCELLS. AS THE ASCENT CONTINUES TO SPREAD EAST THIS
AFTERNOON...ADDITIONAL DEEP MOIST CONVECTION IS EXPECTED WITH ALL
SEVERE HAZARDS LIKELY GIVEN AFOREMENTIONED THERMODYNAMIC AND
KINEMATIC FIELDS.

..PETERS/THOMPSON.. 04/29/2016


ATTN...WFO...FWD...EWX...SJT...

[davidiowx]

Small little cell forming down on the Ft Bend / Brazoria county boarder. Looks like things are going to start getting going as the afternoon progresses.

[BlueJay]

The wind has picked up here but otherwise the weather is deceivingly lovely.

[tireman4]

Stay alert folks.........


@NWSHouston
Skywarn spotter activation will probably be needed in the College Station area around 3 pm. We will have the HAM @skywarn net active at 3 pm

[jasons2k]

It''s hot!! 90f here...

[srainhoutx]

It''s hot!! 90f here...

89F here in NW Harris County...which is a bit worrisome regarding the cap breaking.

[davidiowx]

I am not looking at a cap map but storms are starting to fire SW of the metro... It is only 2 in the afternoon so it seems to be breaking down as we speak.

[Texaspirate11]

I am not looking at a cap map but storms are starting to fire SW of the metro... It is only 2 in the afternoon so it seems to be breaking down as we speak.

I can barely breathe down here by the bay - so hot and humid

[tireman4]

Welcome to Summer Miss Pirate...ughh..I want Fall back..LOL

[srainhoutx]

04292016 mcd0150.gif

MESOSCALE PRECIPITATION DISCUSSION 0150
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
309 PM EDT FRI APR 29 2016

AREAS AFFECTED...CENTRAL TEXAS

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 291909Z - 292309Z

SUMMARY...MULTIPLE CONVECTIVE BANDS DEVELOPING IN DEEP MOISTURE
CHANNEL OUT OF THE WESTERN GULF. FLASH FLOODING POSSIBLE GIVEN
RATES OVER 2" PARTICULARLY FURTHER EAST ALONG TPW AXIS.

DISCUSSION...GOES-14 SRSO VIS/IR LOOP INDICATING CONVECTION
DEVELOPING ALONG EASTERN EDGE OF CHANNEL OF DEEPER MOISTURE
EXTENDING OUT OF THE FAR WESTERN GULF ACROSS CENTRAL TX. THIS
CONVECTION IS DEVELOPING ALONG THE RAP/BLENDED TPW MOISTURE AXIS
THAT CONTINUES TO INCREASE DUE TO STRONG LOW LEVEL MST TRANSPORT
ON 45-50KT LLJ PER VWP NETWORK...WITH VALUES OF 1.75" NEAR THE
GULF COAST AND UP TO 1.5" JUST EAST OF THE DFW METRO. VIS LOOP
ALSO INDICATES A DRY SURGE INDICATED BY AN ARCHED ROLL CLOUD
MOVING THROUGH COASTAL TX/SW LA...THIS SURGE WILL CONTINUE
NORTHWARD AND ALLOW FOR CONTINUED LOW LEVEL STABILIZATION AND
SUPPORT A CONTINUED CORRIDOR OF DEEPER MOISTURE FLUX ON THE
INTERFACE. DEEPER SOUTHERLY FLOW ALSO SUPPORTS CELL MOTIONS TO BE
ENE ALONG THIS INTERFACE LEADING TO POTENTIAL REPEAT/TRAINING
TRACKS. THOUGH ORIENTATION TO THE LOW LEVEL FLOW WILL KEEP FLUX A
BIT LOWER THAN FURTHER NORTH NEAR THE E-W BOUNDARY ACROSS N TX/N
LA...THERE SHOULD BE SUFFICIENT FLUX TO KEEP CELL EFFICIENCIES
HIGH. ADDITIONAL SUPPORT FOR WARM CLOUD/RAINFALL EFFICIENT IS
DRIVEN BY HIGH DENSITY OF SMOKE METEORS FROM YUCATAN/TABASCO
AGRICULTURAL FIRES AND WILL ACT AS CONDENSATION NUCLEI FOR MORE
NUMEROUS RAINDROP PRODUCTION... ALL CONSIDERED RATES OF 2-3"/HR
ARE PROBABLE.

FURTHER WEST...SURFACE CYCLOGENESIS SOUTH OF THE RED RIVER AND E
OF 100W IS PROVIDING INCREASED LOW LEVEL MOISTURE CONVERGENCE FROM
ISALLOBARIC FLOW TO INITIATE CONVECTION ALONG THE WESTERN EDGE OF
THE MOISTURE CHANNEL. STEEPENED LAPSE RATES HELPS TO INCREASE
SBCAPES OVER 4000 J/KG. THESE FACTORS COMBINED WILL CONTINUE TO
DEVELOP/EXPAND CONVECTIVE COVERAGE...THAT WILL START TO PROGRESS
EASTWARD TOWARD THE DEEPER MOISTURE AND PRESENT A POSSIBILITY OF
CELL MERGERS AND EVENTUAL CONSOLIDATION INTO A LARGER CONVECTIVE
COMPLEX TOWARD MID-EVENING.

CONFIDENCE IN EXACT MERGING/CONSOLIDATION SCENARIO IS A BIT LOWER
GIVEN MUCH OF THE HI-RES CAMS HAVE BEEN MUCH TOO SLOW IN
DEVELOPING THIS WESTERN CONVECTIVE LINE AND HAD FOCUSED ON THE
EASTERN MOISTURE AXIS DEVELOPMENT. GREATER THREAT REMAINS FURTHER
EAST GIVEN SLOWER EASTWARD PROGRESSION OF THE LINE/MOISTURE
AVAILABILITY AND POTENTIAL FOR TRAINING.

GALLINA

ATTN...WFO...EWX...FWD...HGX...SHV...

[DoctorMu]

Stay alert folks.........


@NWSHouston
Skywarn spotter activation will probably be needed in the College Station area around 3 pm. We will have the HAM @skywarn net active at 3 pm

Cells blowing up just N of CLL and turning severe quickly

[DoctorMu]

Cloud seeding. Nice.

ADDITIONAL SUPPORT FOR WARM CLOUD/RAINFALL EFFICIENT IS
DRIVEN BY HIGH DENSITY OF SMOKE METEORS FROM YUCATAN/TABASCO
AGRICULTURAL FIRES AND WILL ACT AS CONDENSATION NUCLEI FOR MORE
NUMEROUS RAINDROP PRODUCTION... ALL CONSIDERED RATES OF 2-3"/HR
ARE PROBABLE.

[srainhoutx]

2:30 PM (Friday) Update from Jeff:

****Potentially dangerous weather event late this afternoon into early Saturday****

Flash Flood Watch is in effect

Tornado Watch will likely be issued in the next few hours.

Air mass is becoming very unstable given the large amount of heating we have seen this morning.

Cap is eroding and recent cell development over Fort Bend County is likely the start of scattered development. Severe threat is high the next several hours west of I-45 where heating has pushed instability into the 3000-4000 J/kg range. Cap is still weakening….but once it is removed…look out…things are going to blow. Think the tornado threat is higher the next several hours in the Huntsville to Columbus area where instability is maximized and then this threat shifts slowly eastward into the evening hours and also will include damaging winds and large hail.

Getting very worried about a significant flash flood event across SE TX tonight. Low level flow all the way from the Caribbean is transporting tremendous moisture into the region. PWS currently surging to over 2.0 inches is tropical. Excellent low level inflow against a slow WSW to ENE boundary is very worrying as this is a classic flash flood setup for SE TX. Recent meso scale models including the HRRR blast the area with tremendous rainfall overnight. All indicators are pointing toward a significant event…but the exact location remains in question….must watch radar trends closely the next several hours.

Tremendous rainfall amounts of 2-4 inches per hour will be possible with these storms which is going to lead to rapid flash flooding. Everyone should have a plan of what they are going to do if flooding begins at your location. Such rainfall rates can produce flooding well away from creeks and bayous where the underground system becomes overwhelmed with the large volume of water in a short period of time.

I cannot stress enough not to drive into flooded roadways!

[djjordan]

Thanks Mexico!!!! LOL

Cloud seeding. Nice.

ADDITIONAL SUPPORT FOR WARM CLOUD/RAINFALL EFFICIENT IS
DRIVEN BY HIGH DENSITY OF SMOKE METEORS FROM YUCATAN/TABASCO
AGRICULTURAL FIRES AND WILL ACT AS CONDENSATION NUCLEI FOR MORE
NUMEROUS RAINDROP PRODUCTION... ALL CONSIDERED RATES OF 2-3"/HR
ARE PROBABLE.

[Ounce]

Thanks Mexico!!!! LOL

Cloud seeding. Nice.

ADDITIONAL SUPPORT FOR WARM CLOUD/RAINFALL EFFICIENT IS
DRIVEN BY HIGH DENSITY OF SMOKE METEORS FROM YUCATAN/TABASCO
AGRICULTURAL FIRES AND WILL ACT AS CONDENSATION NUCLEI FOR MORE
NUMEROUS RAINDROP PRODUCTION... ALL CONSIDERED RATES OF 2-3"/HR
ARE PROBABLE.

Just a little Tabasco sauce is all we want.

[davidiowx]

Thanks Mexico!!!! LOL

Cloud seeding. Nice.

ADDITIONAL SUPPORT FOR WARM CLOUD/RAINFALL EFFICIENT IS
DRIVEN BY HIGH DENSITY OF SMOKE METEORS FROM YUCATAN/TABASCO
AGRICULTURAL FIRES AND WILL ACT AS CONDENSATION NUCLEI FOR MORE
NUMEROUS RAINDROP PRODUCTION... ALL CONSIDERED RATES OF 2-3"/HR
ARE PROBABLE.

Just a little Tabasco sauce is all we want.

Lol.. All we need is a little more heat.. No thank you!