May 2016: Shower/Storm Chances To End May

[kayci]

Sooo... we good for tonight? it's 8:30 pm. Alvin just having winds. Just wondering, no posts for awhile and looking forward to a quiet good night sleep here in Brazoria Co.

[djjordan]

Sooo... we good for tonight? it's 8:30 pm. Alvin just having winds. Just wondering, no posts for awhile and looking forward to a quiet good night sleep here in Brazoria Co.

Chances of storm development remain overnight so you may be awakened in the middle of the night by some storms. Not certain if Alvin will be a hit or miss but precip chances are going to remain in the 50-70% chance range all night. This cap has protected most of us all weekend long which of course is a great thing.

Here's the Forecast discussion hot off the presses from the NWS:

.DISCUSSION...
AT 930 PM A SURFACE TROUGH/OUTFLOW BOUNDARY WAS LOCATED BETWEEN
ONALASKA TO EAGLE LAKE NEAR COLUMBUS. A STATIONARY FRONT WAS
FURTHER INLAND NEAR A LINE FROM LUFKIN TO COLUMBUS. A LINE OF
SHOWERS AND ISOLATED THUNDERSTORMS HAS PERSISTED ALONG THE OUTFLOW
BOUNDARY FOR MOST OF THE EVENING. EVEN THOUGH ISOLATED AREAS HAVE
RECEIVED IN EXCESS OF 4 INCHES OF RAINFALL...MOST LOCATIONS HAVE
RECEIVED UNDER A QUARTER OF AN INCH.

THE MAIN ITEM OF CONCERN FOR TONIGHT AND MONDAY MORNING WILL BE
ISOLATED AREAS OF LOCALIZED HEAVY RAINFALL. THIS WILL BE DUE TO
THE SLOW MOVEMENT OF ANY ISOLATED THUNDERSTORMS THAT DEVELOP.

THE MODELS HAVE HAD A DIFFICULT TIME HANDLING THE RAIN AREAS THIS
EVENING. THERE WAS AN ABUNDANCE OF MOISTURE AVAILABLE...AS SEEN BY
DEWPOINTS OF ABOUT 12 C AT 850 MB AND 4-5 C AT 700 MB. HOWEVER...
THE MOISTURE AXIS WAS RATHER NARROW AND WAS LOCATED MAINLY OVER
THE STATIONARY FRONTAL BOUNDARY. FELT THAT THE SHOWERS AND
ISOLATED STORMS WERE BEING GENERATED MAINLY BY THE PASSAGE OF AN
UPPER JET STREAK AND A MID LEVEL SHORTWAVE TROUGH THAT CAN BE SEEN
ON THE WATER VAPOR. A CONSENSUS OF THE SHORT RANGE MODELS KEEPS
BEST RAIN CHANCES ALONG THE BOUNDARY FOR THE REST OF THE EVENING.
AFTER MIDNIGHT...THERE IS A CHANCE THAT ADDITIONAL SHOWERS AND
ISOLATED THUNDERSTORMS WILL DEVELOP AS THE RIGHT-REAR QUADRANT OF
THE JET MOVES OVERHEAD. FOR THAT REASON... KEPT A 50 TO 60 PERCENT
CHANCE OF RAIN ALONG AND EAST OF THE HIGHWAY 59 CORRIDOR FOR THE
OVERNIGHT PERIOD.

[DoctorMu]

Some cap breaking north and west of Houston. Flooding possible near Livingston.

[djjordan]

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1057 PM CDT SUN MAY 1 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
NORTHWESTERN SAN JACINTO COUNTY IN SOUTHEASTERN TEXAS...
WEST CENTRAL POLK COUNTY IN SOUTHEASTERN TEXAS...

* UNTIL 100 AM CDT

* AT 1056 PM CDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING
HEAVY RAIN ACROSS THE WARNED AREA. UP TO TWO INCHES OF RAIN HAVE
ALREADY FALLEN ON ALREADY RAIN-SATURATED GROUND. FLASH FLOODING IS
EXPECTED TO BEGIN SHORTLY.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
LIVINGSTON...ONALASKA...POINT BLANK...SEVEN OAKS...NORTHERN WEST
LIVINGSTON...LEGGETT AND OAKHURST.

ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE POSSIBLE IN THE
WARNED AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TURN AROUND...DON`T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING.

PLEASE REPORT FLOODING TO YOUR LOCAL LAW ENFORCEMENT AGENCY WHEN YOU
CAN DO SO SAFELY.

&&

[DoctorMu]

Could be some issues around dawn in the Houston area. Not sure there will be profuse rain, but it won't take much to initiate or exacerbate flooding.

[DoctorMu]

Wettest April ever at IAH, 6th wettest at Hobby



Potential for the east side of HOU to see 2-3 inches. Another low confidence forecast, especially at the local level as heavy rain will be isolated.




AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1003 PM CDT SUN MAY 1 2016

.DISCUSSION...
AT 930 PM A SURFACE TROUGH/OUTFLOW BOUNDARY WAS LOCATED BETWEEN
ONALASKA TO EAGLE LAKE NEAR COLUMBUS. A STATIONARY FRONT WAS
FURTHER INLAND NEAR A LINE FROM LUFKIN TO COLUMBUS. A LINE OF
SHOWERS AND ISOLATED THUNDERSTORMS HAS PERSISTED ALONG THE OUTFLOW
BOUNDARY FOR MOST OF THE EVENING. EVEN THOUGH ISOLATED AREAS HAVE
RECEIVED IN EXCESS OF 4 INCHES OF RAINFALL...MOST LOCATIONS HAVE
RECEIVED UNDER A QUARTER OF AN INCH.

THE MAIN ITEM OF CONCERN FOR TONIGHT AND MONDAY MORNING WILL BE
ISOLATED AREAS OF LOCALIZED HEAVY RAINFALL. THIS WILL BE DUE TO
THE SLOW MOVEMENT OF ANY ISOLATED THUNDERSTORMS THAT DEVELOP.

THE MODELS HAVE HAD A DIFFICULT TIME HANDLING THE RAIN AREAS THIS
EVENING. THERE WAS AN ABUNDANCE OF MOISTURE AVAILABLE...AS SEEN BY
DEWPOINTS OF ABOUT 12 C AT 850 MB AND 4-5 C AT 700 MB. HOWEVER...
THE MOISTURE AXIS WAS RATHER NARROW AND WAS LOCATED MAINLY OVER
THE STATIONARY FRONTAL BOUNDARY. FELT THAT THE SHOWERS AND
ISOLATED STORMS WERE BEING GENERATED MAINLY BY THE PASSAGE OF AN
UPPER JET STREAK AND A MID LEVEL SHORTWAVE TROUGH THAT CAN BE SEEN
ON THE WATER VAPOR. A CONSENSUS OF THE SHORT RANGE MODELS KEEPS
BEST RAIN CHANCES ALONG THE BOUNDARY FOR THE REST OF THE EVENING.
AFTER MIDNIGHT...THERE IS A CHANCE THAT ADDITIONAL SHOWERS AND
ISOLATED THUNDERSTORMS WILL DEVELOP AS THE RIGHT-REAR QUADRANT OF
THE JET MOVES OVERHEAD. FOR THAT REASON... KEPT A 50 TO 60 PERCENT
CHANCE OF RAIN ALONG AND EAST OF THE HIGHWAY 59 CORRIDOR FOR THE
OVERNIGHT PERIOD.

MADE SOME UPDATES TO THE POPS AND WEATHER FOR TONIGHT AND MONDAY
MORNING.

[srainhoutx]

Severe Thunderstorm Watch remains in effect until 9:00 generally from Montgomery County on NE. Approaching jet streak from the West and a stronger front pushing SE over Texas could fire additional storms today.

MESOSCALE DISCUSSION 0530
NWS STORM PREDICTION CENTER NORMAN OK
0243 AM CDT MON MAY 02 2016

AREAS AFFECTED...SOUTHEAST TX...WEST LA...SOUTH AR

CONCERNING...01Z OUTLOOK UPGRADE

VALID 020743Z - 020945Z

SUMMARY...THE REGION IS EFFECTIVELY UPGRADED TO MARGINAL/SLIGHT
RISKS THROUGH THE REST OF THE CURRENT OUTLOOK PERIOD ENDING AT 12Z.
SEVERE THUNDERSTORM WATCH ISSUANCE IS BEING CONSIDERED.

DISCUSSION...A FEW SUPERCELLS ARE ONGOING WITHIN THE SWATH OF
SCATTERED STORMS ACROSS SOUTHEAST TX INTO SOUTH AR. PRESENCE OF
ROBUST SPEED SHEAR WITHIN THE ELEVATED BUOYANT LAYER CONTINUES TO
FOSTER UPDRAFT ROTATION PROMOTING LARGE HAIL GROWTH FROM SPLITTING
CELLS. THE LARGELY DISCRETE NATURE OF THE CONVECTION HAS MAINTAINED
WELL-DEVELOPED SUPERCELL STRUCTURES. WITHIN THE DIFFLUENT FLOW
REGIME IN LEFT-EXIT REGION OF AN UPPER JET...STORMS WILL LIKELY
PERSIST FOR THE NEXT SEVERAL HOURS.

..GRAMS/GOSS.. 05/02/2016


ATTN...WFO...JAN...LZK...LCH...SHV...HGX...FWD...

[srainhoutx]

94ewbg (7).gif

OF IMMEDIATE AND SHORT TERM CONCERN IS THE LATEST HRRR/ARW RUNS
THAT CONTINUE TO PINPOINT AN ORGANIZED AREA OF CONVECTION EVOLVING
FROM SOUTHEAST TX INTO SWRN LA. THIS IS WHERE A SMALL SCALE
DISTURBANCE GLIDING ALONG THE SUBTROPICAL JET WILL INTERACT WITH A
VAGUE CONVERGENCE AXIS OF DEEP TROPICAL MOISTURE WITH DEWPTS OF 70
DEG OR HIGHER DRIFTING NORTH OVER THE NWRN GULF OF MEXICO. A
POSSIBLE CONVECTIVE COMPLEX OR MULTIPLE ZONES OF HEAVY RAINFALL IS
ANTICIPATED ACROSS THE TWO STATES AND WPC JUST ISSUED MPD 168 FOR
THIS AREA. THIS COMPLEX SHOULD PROPAGATE DOWNSTREAM BUT THE
COMBINATION OF EXTREMELY LOW FFG AND STALLED FRONTAL ZONE OVER
SOUTH TX SUGGESTS EVEN BACK-BUILDING POTENTIAL NEAR THE SWRN
PERIPHERY OF SUCH A FEATURE. THOUGH WPC QPF DOES NOT DEPICT IT
AREAL-WISE... MESO AMOUNTS OF 2-4 INCHES WITH LOCALLY HIGHER
VALUES WILL BE POSSIBLE INVOF VULNERABLE SERN TX/SWRN LA AND WPC
WENT WITH A MDT THREAT FOR EXCESSIVE RAINS.

MUSHER

[srainhoutx]

After today we should have a good chance to dry out. Beginning to see some indications that by next Sunday, another messy, wet and potentially stormy period sets up once again with a very deep SW trough and noisy SW flow aloft...but we will look at that later this work week.

NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
450 AM CDT MON MAY 2 2016

.DISCUSSION...
LOOKING FOR CONTINUED AREAS OF SHRA/TSRA FOR THE NEXT SEVERAL
HOURS. FRONTAL BOUNDARY HASN`T MOVED ALL THAT MUCH OVERNIGHT...STILL
ROUGHLY SITUATED ALONG THE HIGHWAY 59 CORRIDOR. THINK HAIL AND
ISOLATED HEAVY DOWNPOURS WILL BE THE MAIN ISSUE NORTH OF I-10
WHERE BETTER DIFFLUENT FLOW ALOFT SHOULD BE SITUATED THRU LATE
MORNING. ANOTHER BOUNDARY SOUTH OF I-10 FIRED UP EARLIER IN THE
NIGHT AND IS DOING SO AGAIN. MORE EFFICIENT RAINFALL RATES ARE
EXPECTED HERE. COVERAGE SHOULD ALSO BE HIGHER AND AREA WILL BE
CLOSELY WATCHED AS IT SERVES AS A TRAINING/FOCUSING MECHANISM.
TIDE LEVELS SHOT UP OVERNIGHT SO DRAINAGE WON`T BE AS GOOD AS
USUAL AT SOME LOCATIONS. GUIDANCE BRINGS THE FRONT THRU LATER RE
REMAINDER OF THE AREA LATER THIS MORNING AND EARLY AFTERNOON
BRINGING DRIER AIR TO THE COAST. MAY STILL SEE SOME ISO/SCT
ELEVATED PRECIP IN ITS WAKE...BUT EXPECT A DRYING TREND TO FINALLYBEGIN.

AFTER TODAY WE SHOULD SEE ABOUT A WEEK OF NEEDED DRY PLEASANT WX
WITH UPPER RIDGING GAINING CONTROL. TEMPS SHOULD BE CLOSE TO
CLIMO WITH LOWS IN THE 60S & HIGHS IN THE 80S. ONSHORE FLOW
RESUMES THIS WEEKEND AND UPPER RIDGE MOVES OFF TO THE EAST. RAIN
CHANCES RETURN EARLY NEXT WEEK AS WE GET INTO THE MESSY SW FLOW IN
ADVANCE OF THE NEXT APPROACHING UPPER TROF. 47

[nuby3]

I have this weird feeling that what I expected Saturday will come today instead. haha

[djmike]

Looks like we might get lucky. Looks like things are having a hard time getting started. Lastnight into this morning was the time for heavy rains we heard about all week. Of anything storm looks to be petering out.

[djmike]

And passing all to the north of us headed NE.

[Katdaddy]

Finally and extended period of sunny skies and dry weather on the way for SE TX.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1041 AM CDT MON MAY 2 2016

.DISCUSSION...
WITH THE COLD FRONT NOW OFF THE COAST AND NORTH WINDS SHOWING UP AT
ALL SOUTHEAST TEXAS OBSERVATION SITES...LOOK FOR DECREASING SHOWER/
THUNDERSTORM COVERAGE AS THE DAY PROGRESSES TODAY... AND DECREASING
CLOUD COVER TONIGHT AS SURFACE HIGH PRESSURE BUILDS INTO THE STATE.
THE REST OF THE WEEK WILL BE SUNNY WITH COOL NIGHTS AND WARM DAYS.

[Ounce]

It appears the showers NE of Beaumont are heading SE, rather than NE. I guess the front is influencing them SE and the showers in mid-LA are raining themselves out.

The remaining showers west of I-35 are still headed NE.

[Katdaddy]

Mid to high level clouds will gradually clear across SE TX today leading to beautiful weather through the remainder of the week. Sunny skies with highs in the low 80s and lows in the upper 50s to low 60s. A well needed break from the unsettled weather pattern.

[Katdaddy]

Beautiful sunny dry weather to continue through Saturday across SE TX. Temps in the upper 50s and low 60s this morning. Just about as good as it gets for early May.

[srainhoutx]

Hope everyone is enjoying this pleasant and dry break in our weather pattern. It has been a welcomed break after the almost 3 weeks of unsettled weather that produced near record Regional Rainfall.

The next storm system is slowly moving toward California and the Gulf will begin to slowly open up with a return flow becoming established over the weekend. Sunday into early next week we may see thunderstorms develop along the dryline to our West as the upper trough and a cold core upper low move ENE out of the Great Basin toward the Plains. I do not see another heavy rainfall threat at this time, but we may see a chance of some isolated heavier storms Monday into Tuesday as the upper low shears out well to our N and the return flow off the Gulf of Mexico continues.

[srainhoutx]

The afternoon Update Climate Prediction Center Day 6 to 10 Outlook suggests we may return to a bit of a 'wetter' pattern as a series of troughs indicated by the shades of Blue remain overhead.

[srainhoutx]

Starting to see some changes in the upper air pattern particularly across Texas into Louisiana as the upcoming work week unfolds. Currently the Gulf into the Western Caribbean have been swept clear of deep tropical moisture, but that situation appears to relax as deeper moisture begins to advance W and NW with a prolonged SE flow.

The Omega Block appears to break down over Western Canada as a rather deep upper trough currently across the Central Pacific slowly advances East toward the West Coast. At the same time an unusually strong upper trough develops near the Great Lakes Region with a stalling frontal boundary draped across the Red River Valley. Increasing moisture with higher temperatures and increasing dewpoints suggest increasing chances of daily seabreeze storms as the work week ends.

In the longer range, there are some indications that a monsoonal trough may attempt to organize across the NW Caribbean Sea and eventually into the Southern Gulf. Will need monitor the trends over the next week to see if the Extended Forecasts suggested by the ensemble guidance are correct with a return to an unsettled and potentially wet pattern that could last into Memorial Day. We will see.

[srainhoutx]

Morning briefing from Jeff:

Strong gradient winds in progress this morning along and SE of US 59. Surface obs showing frequent gusts of 35-40mph…with 41mph just recorded at Victoria. Will continue with these winds through about the noon hour then see a gradual weakening as the pressure gradient slackens. Could see gusts this morning enough to bring down a few tree limbs and produce some power outages.

Band of light to moderate rainfall associated with an ejecting short wave out of MX will be progressing off the coast in the next few hours. Moisture has yet to fully return to the region even though surface dewpoints are pushing the mid to upper 60’s…it is dry in the mid levels which is resulting in a lot of the rainfall evaporating before reaching the ground.

Will see skies clear early this afternoon and the dryline mix eastward to near/east of I-35. Heating will push temperatures into the lower to mid 80’s resulting in building instability below a mid level capping inversion. While chances appear small there will be a window late this afternoon when surface heating will weaken the cap and may allow a few thunderstorms to erupt along the dryline. Given the instability that will be in place any storms that form could quickly become severe. Will maintain the best chances for any convection north of a line from College Station to Liberty with the highest severe threat around and NE of Lake Livingston. Overall severe threat is conditional on the cap being broken and storms actually developing.

Short wave ridge builds over the area tomorrow into Wednesday resulting in reduced rain chances and warm temperatures…highs well into the 80’s or even near 90. Dryline will retreat to W TX awaiting the next upper trough progression into the plains. That trough arrives on Thursday and actually drops a weak cool front into TX. Air mass south of that boundary will become very unstable by late afternoon over C and SE TX and expect thunderstorms to erupt along the boundary. Could be some severe weather given what looks to be good instability and shear…but there are some questions on quality of moisture and of course the never ending question of cap strength.

It is starting to get to that time of year where fronts really don’t bring much air mass change and this front on Thursday looks to wash out over the region on Friday. Might see a small drying trend, but muggy air mass will push back inland late Friday into the weekend. Upper ridge begins to build in from the Gulf of Mexico…a sign that summer is not far away…but heat and humidity may be enough to keep afternoon thunderstorm chances in the forecast over the weekend along the seabreeze.

Far long range guidance suggest the gradual formation of a monsoon trough over the western Caribbean Sea into the southern Gulf of Mexico and far eastern Pacific Ocean with deep tropical moisture across that region. Will have to see if any of this moisture may attempt to connect with any deep troughs over the SW US in late May across the southern plains. Also a sign that hurricane season is nearing.