Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 5

[DoctorMu]

[1900hurricane]

 

MESOSCALE PRECIPITATION DISCUSSION 0048
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
247 PM EDT MON MAY 12 2014

AREAS AFFECTED...EASTERN OK...NORTHEAST AND CENTRAL TX

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

VALID 121846Z - 130046Z

SUMMARY...ORGANIZED THUNDERSTORMS WITH HEAVY RAINFALL ARE EXPECTED
TO MOVE ACROSS EASTERN OK, NORTHEAST TX, AND THE TX HILL COUNTRY
OVER THE NEXT SEVERAL HOURS. REGIONAL FLASH FLOODING IS
CONSIDERED POSSIBLE IN THESE AREAS.

DISCUSSION...THE COMBINATION OF A SLOWLY PROGRESSIVE COLD FRONT,
PRECIPITABLE WATER VALUES OF 1.75-2 INCHES (BETWEEN THE 90TH AND
99TH PERCENTILES FOR MID-MAY), 0-3 KM WIND SHEAR OF OVER 25 KNOTS,
AND CAPE VALUES OF 2000-4000 J/KG HAS ORGANIZED A NARROW BAND OF
THUNDERSTORMS ACROSS PORTIONS OF TX AND OK, WITH A CLUSTER
CURRENTLY FORMING ACROSS SOUTHEAST OK. WITH 850 HPA INFLOW
EXCEEDING THE 850-400 HPA MEAN WINDS ACROSS TX AND OK, HEAVY RAINS
ARE LIKELY WITH THIS ACTIVITY, ON THE ORDER OF 2" AN HOUR WITHIN
STRONGER CONVECTION.

THE MESOSCALE GUIDANCE IS IN GENERAL AGREEMENT THAT THUNDERSTORM
ACTIVITY NEAR THE MOST EXTREME CAPE, COMBINED WITH DRY AIR ALOFT,
SHOULD CAUSE A COLD POOL TO FORM IN ASSOCIATION WITH THE
NORTH-CENTRAL TX, AND POSSIBLY SOUTHEAST OK, CONVECTION AND ALLOW
IT TO BOW OUT SOMEWHAT TO THE SOUTHEAST ACROSS THE HILL COUNTRY
INTO THIS EVENING. AS IT DOES SO, INFLOW INTO THE BAND WILL
INCREASE AND RAINFALL EFFICIENCY SHOULD INCREASE AT THE EXPENSE OF
THUNDERSTORM ACTIVITY FARTHER TO THE NORTHEAST. HIGH FLASH FLOOD
GUIDANCE VALUES ACROSS THE REGION, ON THE ORDER OF 3-4" IN THREE
HOURS, PRECLUDED THE IDEA OF THE LIKELY CATEGORY. LOCAL RAINFALL
AMOUNTS OF 4"+ ARE POSSIBLE ACROSS CENTRAL TX BY SUNSET, WHICH
COULD LEAD TO REGIONAL FLASH FLOODING.

ROTH

ATTN...WFO...SHV...TSA...HGX...FWD...OUN...EWX...SJT...

ATTN...RFC...ABRFC...LMRFC...WGRFC...

LAT...LON 33489722 34689642 35969570 35919459 33249479 30169590
29319746 29449861 29799917 30179940 30509962 30959982
30969981 31369929 31929846 32809763 33489722 

[Srain]

From Nesdis:

 

SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 05/12/14 2334Z
SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-683-1404
LATEST DATA USED: GOES-13 2325Z  HANNA
.
LOCATION...LOUISIANA...ARKANSAS...TEXAS...
.
ATTN WFOS...SHV...HGX...FWD...CRP...EWX...SJT...
ATTN RFCS...LMRFC...ABRFC...WGRFC...
.
EVENT...UPDATE TO EARLIER SPENES FOR ONGOING HEAVY RAINFALL EVENT
.
SHORT TERM OUTLOOK VALID 0000-0600Z...MEDIUM CONFIDENCE FACTOR
IN SHORT TERM OUTLOOK...CONVECTIVE LINE HAS BEEN SLOWLY PROGRESSIVE
THROUGH MUCH OF NE TX WITH REPORTS FROM FWD WFO OF 2.0-3.0" TOTALS.
HCRS CONTINUE TO ENHANCE OVER E/NE TX WITH CB DEVELOPING JUST W OF GGG
AND THIS SHOULD FEED INTO LINE TO ENHANCE RAINFALL TOTALS OVER PORTIONS
OF NE TX.  FURTHER TO THE SW CONVECTIVE LINE HAS BEEN MUCH SLOWER TO MOVE
WITH MOISTURE AND INSTABILITY FEEDING NW UP THE RIO GRANDE TO ALLOW FOR
CONTINUED CONVECTIVE REGENERATION AND TRAINING DOWNSTREAM FROM ROUGHLY
ACT EXTENDING WSW TO JUST N OF ECU.  TROF CONTINUES TO AMPLIFY IN THE SW
WHICH SHOULD HOLD BOTH ENTRANCE REGION AND HIGHLY DIFFLUENT FLOW NEARLY
IN PLACE.  WOULD EXPECT THAT SYSTEM SHOULD BE MOSTLY PROGRESSIVE OVER
PORTIONS OF NE TX AND SLIGHTLY LESS PROGRESSIVE OVER PORTIONS OF S CNTRL
TX FOR THE NEXT FEW HOURS.  GOES SOUNDER DOES SHOW HIGHLY UNSTABLE AIR
MASS UPSTREAM SO WOULD EXPECT THAT SYSTEM SHOULD EVENTUALLY BECOME MORE
PROGRESSIVE WITH TIME OVER S CNTRL TX AND BEGIN ACCELERATING TOWARDS
PERHAPS 03Z WHICH WILL LIKELY DECREASE THE HEAVY RAIN THREAT FURTHER
SOUTH.  WAS KEEPING AN EYE FOR THE POTENTIAL INTERACTION BETWEEN LINE
AND CONVECTION OVER N MEXICO BUT MOST OF THOSE HAVE BEEN RIGHT MOVERS
DROPPING SE.  THERE WAS STILL IMPULSES UPSTREAM TO POTENTIALLY ALLOW
FOR SOME CONTINUED CONVECTION OVER N MEXICO TO INTERACT WITH EXISTING
MCS BUT THAT IS BECOMING LESS CERTAIN.  STILL THOUGH WOULD EXPECT SOME
LOCALIZED 4.0-6.0" TOTALS POSSIBLE ROUGHLY ALONG AN AXIS FROM THE VIC
OF ECU/ERV EXTENDING NE TO S OF ACT.
 

[DoctorMu]

She's coming down at 0.5-1 in/hr in CLL

 

 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
835 PM CDT MON MAY 12 2014

.UPDATE...
PRIMARILY DISCRETE SHOWER ACTIVITY...WITH EMBEDDED ISOLATED
STORMS/MORE ORGANIZED N-S ORIENTED CONVECTIVE LINES...BLOSSOMING
UP ACROSS THE NORTHWEST-NORTH CWA AND FEEDING INTO THE MAIN QLCS
CURRENTLY ENTERING OUR FAR NORTHERN CWA. COOL POOL SEEMING TO KICK
IN ALONG ITS WESTERN FLANK AND PUSHING THIS ONCE VERY SLOW-MOVING
LINE MORE PROGRESSIVELY SE`WARD INTO OUR FORECAST AREA. SHORT TERM
HIGH REZ MODELING HAS A MORE RAGGED CONVECTIVE LINE SPEEDING UP
AND REACHING THE NORTHERN FRINGES OF THE CITY AROUND MIDNIGHT OR 1
AM...TO THE COAST BY 3 OR 4 AM. THESE SOLUTIONS ALSO PROVIDE THE
GREATEST SOUTHERN PUSH TO THE LINE ACROSS THE WESTERN CWA
THUS...WITH THIS VELOCITY...AREAWIDE AVERAGE QPF WILL BE UNDER TWO
INCHES WITH LOCALIZED 3 TO 4 INCHES. BULK OF RAIN SHOULD FALL
ALONG AND WEST OF I-45 THROUGH TUESDAY MORNING. NEVERTHELESS...THE
PROBABILITY OF LOCALIZED 3-4 INCH TOTALS...LEADING TO NUISANCE
FLOODING OF LOCAL AREA ROADWAYS...WILL MAINTAIN TUESDAY MORNING`S
NW`ERN CWA`S FLASH FLOOD WATCH. 31
 

 

 

 

 

 

[1900hurricane]

Glorious.

Sent from my iPhone using Tapatalk

[Ed Lizard]

My lawn is happy.

 

Over 1.5 inches MBY per 88D (I should ask for a rain gauge for Christmas) and 2 inch rain line approaching.

 

DWH and IAH suggests that rainfall estimate may even be a touch low...

[CranberryWX]

As of 7AM I recorded 4.01" of rain in my gauge. Still light rain falling. Continuous rain since 10:30 PM last night.

[Srain]

Update from Jeff:

 

Quite the overnight rainfall cross the area with numerous locations getting between 4-7 inches of rainfall with up to 8 inches in Colorado County. Ongoing run-off and flooding is the main near term focus.

 

Widespread 3-5 inches of rainfall has fallen overnight along and NW of US 59 with almost no rainfall over Galveston or Chambers Counties…models actually did handle the sharp cut-off very well. Excessive short term rainfall rates area resulting in significant run-off into area rivers and stream even though grounds were dry going into the event.

 

Meso low has been generated along the upper TX coast in response to strong forcing from convection overnight. This feature has lost much of its identity in the last few hours and gusty wind associated with the small scale pressure gradient have ended. Outflow boundary and cold pool which helped force heavy rainfall deeper into SE TX overnight is starting to weaken as it crosses into the Gulf waters and has shown very little additional development in the last hour suggesting this convective complex is weakening. Additionally cloud tops are warming and large mass of convectively induced stratiform rain is weakening. Expect a fairly quick improvement in conditions over the next 2-3 hours as rainfall dissipates.

 

Main question then becomes how quickly does the thick anvil debris clouds dissipate and can the air mass recover this afternoon ahead of the main trough axis tonight. IR images show a fairly impressive convective complex plowing through S TX with significant high level cirrus clouds pouring northward along and east of I-35, but there is a clearing and thinning trend on the satellite images. Meso low induced meso high sitting directly over SE TX will also help to shut off rainfall and helping in clearing skies. Moisture is already quickly returning up the Rio Grande as noted by developing thunderstorms south and southeast of Del Rio. Think the air mass has time to recover especially since the current activity did not move very far offshore and a return of southerly winds by early afternoon should begin to replenish moisture. Do not expect as organized of activity as this current batch nor as high hourly rainfall rates. Confidence is not great on when nor where development may occur this evening/overnight.

 

Cold front will sweep across the region early Wednesday with a very cool air mass for mid May. Low temperatures Thursday-Saturday will be in the 50’s with highs in the 70’s and 80’s with low humidity.

 

[DoctorMu]

Not quite 3.5 in IMBY.  Glad to see widespread and plentiful precip throughout the HGX area.

 

 

Just saw Brenham reported 14.50 in in the last 12 hrs!

[Srain]

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1031 PM CDT TUE MAY 13 2014

...NEW RECORD FOR GREATEST RAINFALL AT BUSH INTERCONTINENTAL AIRPORT...


HOUSTON BUSH INTERCONTINENTAL AIRPORT HAS RECEIVED 3.18 INCHES OF RAIN
SO FAR TODAY...WHICH IS A NEW RECORD FOR GREATEST RAINFALL FOR MAY 13TH.
THE PREVIOUS RECORD WAS 2.74 INCHES...SET IN 1966.


EVEN THOUGH HOBBY AIRPORT IN SOUTH HOUSTON HAS RECEIVED 3.11 INCHES
SO FAR...THE RAINFALL RECORD OF 3.60 INCHES SET IN 1982...STILL STANDS.

[Srain]

Morning Update from Jeff:

 

Strong cold front has progressed into the Gulf waters overnight brining in an unseasonably cold air mass into the area. Record lows are possible Thursday morning across the area.

 

Upper trough axis is sliding across the region this morning producing a few light to moderate showers, but nothing to the magnitude of yesterday morning. Gusty NW winds continue to usher in a drier air mass with temperatures running in the 50’s for most of the region. Rain will end fairly quickly this morning as the trough axis moves eastward with clouds starting to clear this afternoon. Afternoon highs in the lower 70’s with low humidity will be a treat for mid May.

 

Clear skies and light winds tonight will result in cool conditions with near record lows in the upper 40’s to near 50. Record for IAH is 49 and the forecast is 50 so we could easily tie or break that record which has been around since the 1890’s.

 

Very slow return of humidity toward the weekend as high pressure begins to move eastward. NW flow aloft will bring upper air disturbances toward NE TX starting Friday, but think SE TX will be too far SW for dynamics to produce much in our area. Might have to watch any outflow boundaries that could move southward during peak heating, but think moisture return will just be getting underway by Saturday so levels may still be limited.

 

Note: BUSH IAH recorded 3.18 inches of rainfall yesterday breaking a daily rainfall record of 2.74 inches established in 1966.

 

Hydro:
Run-off from the heavy rainfall continues to reach mainstem rivers this morning resulting in rises. Not looking like any systems will reach flood stage.

 

For the first time since 2011, Lake Conroe has risen above its conservation pool level overnight. Current stage is 201.26 with a conservation pool level of 201.0.

[Srain]

PUBLIC INFORMATION STATEMENT...CORRECTED
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
735 AM CDT THU MAY 15 2014

...RECORD LOW TEMPERATURES ACROSS SOUTHEAST TEXAS THIS MORNING...

RECORD LOW TEMPERATURES HAVE BEEN TIED OR SET ACROSS SOUTHEAST
TEXAS THIS MORNING. THE FOLLOWING TABLE LISTS THE LOW TEMPERATURES
ACROSS SOUTHEAST TEXAS AS OF 700 AM CDT TODAY AND THE PREVIOUS
RECORD. NOTE THAT THIS TABLE MAY BE UPDATED LATER TODAY IF THE
MORNING LOW TEMPERATURE IS SET AFTER THE 700 AM OBSERVATION.

FOR THE FIRST-ORDER CLIMATE SITES...

SITE                TEMP    PREV RECORD
COLLEGE STATION      48     50 IN 1942
HOUSTON IAH          49     49 IN 1890
HOBBY AIRPORT        50     53 IN 1976
GALVESTON            55     57 IN 1926

FOR THE SECOND-ORDER CLIMATE SITES...
SITE                TEMP    PREV RECORD

ANGLETON LBX         45     54 IN 2011
BRENHAM 11R          47     47 IN 1942 AND 1926
CLOVER FIELD LVJ     49     56 IN 2002
CONROE CXO           43     47 IN 2011
HOOKS AIRPORT DWH    47     53 IN 2002
HUNTSVILLE UTS       47     48 IN 2011
NWS LEAGUE CITY HGX  47     57 IN 2002
PALACIOS PSX         50     54 IN 2011
SUGAR LAND SGR       48     57 IN 2006 AND 2002
WHARTON ARM          48     51 IN 1905

 

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO, TX
744 AM CDT THU MAY 15 2014

...RECORD LOW TEMPERATURE SET AT DEL RIO...

A RECORD LOW TEMPERATURE OF 47 DEGREES WAS SET AT DEL RIO TODAY.
THIS BREAKS THE OLD RECORD OF 52 DEGREES SET IN 1907.

 

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO, TX
744 AM CDT THU MAY 15 2014

...RECORD LOW TEMPERATURE SET AT SAN ANTONIO...

A RECORD LOW TEMPERATURE OF 47 DEGREES WAS SET AT SAN ANTONIO TODAY.
THIS BREAKS THE OLD RECORD OF 52 DEGREES SET IN 1926.


 

[Srain]

After a number of long time record low temperatures were tied or broken, a quiet and rather benign pattern should set up for the next 6-7 days. There is growing consensus via the global and ensemble guidance that the Eastern Pacific tropical activity may begin to increase along the monsoonal trough and the Euro and GFS are sniffing tropical cyclone genesis possibilities once again next week. It appears the area favored for TC genesis will be just W of the Gulf of Tehuantepec and the various guidance are suggesting another Western trough developing near the same time. While we will warm up, recent rains should help keep our temperature near or slightly above normal. Later next week as the Upper Ridge shift E, a return flow off the Gulf with some enhancement of deep tropical moisture from the NW Caribbean Sea and the Bay of Campeche should slowly increase our rain chances once again.

 

Looking longer range toward the late May time frame, it may be possible that tropical trouble may shift into our Basin in the Western Caribbean/SW Gulf as a robust Kelvin wave spreads convection and instability further E. In a transitioning pattern where El Nino may develop, we often see early season tropical systems develop in the NW Caribbean and Western Gulf. Time will tell.

[DoctorMu]

Conroe really delivered on that low temp.  Navasota and Hearne also hit 47 - BCS at 48 although IMBY 47.

 

A real chamber of Commerce Day.  If only we could bottle this for the summer.

[Srain]

An active weather pattern is developing across Mexico/New Mexico/Texas and Oklahoma. The guidance has advertised for about a week that a slow moving western trough with a meandering 5H low will increase deep tropical moisture from the Pacific and the Western Gulf. As we near the event, it is becoming clear that PW's near 2.0 which is at least 2 to 3 standard deviations above normal will spread across the Region and with strong slow moving storms. The slow movement of the 5H low/trough suggest a heavy rainfall event may develop with training storms possible over the long Memorial Day Weekend.

 

The MJO became less coherent during the past week, as other subseasonal variability combined with the low-frequency state overwhelmed what had been a coherent wave-1 MJO signal. There have been a series of Kelvin waves that propagated rapidly eastward from the Indian Ocean to the Pacific. This has served to pull any remnant enhanced MJO phase eastward toward the Maritime Continent. The RMM index suggests a weak MJO, while the CPC velocity potential index suggests a slightly stronger signal emerging over the far western Pacific. This discrepancy between the two indices is indicative of the generally weak signal at work, one that is easily influenced by higher-frequency variability, the low-frequency state, and the extratropical circulation.

Dynamical and statistical forecasts of the MJO suggest a continued weak signal over the next one to two weeks. Based on recent observations and these model forecasts, the MJO is forecast to remain weak during the period, with any enhanced phase expected to propagate into the Pacific.

The outlooks for Week-1 and Week-2 are based largely on dynamical model consensus, especially where the model forecasts are supported by statistical forecasts that account for the higher-frequency variability. Additionally, the low-frequency state is accounted for, with the outlook reflecting the tendency toward El Niño conditions across the tropical Pacific.

During Week-1, a Kelvin wave currently moving across the far eastern Indian Ocean is expected to enhance convection across parts of the Bay of Bengal and the western Maritime Continent. Another Kelvin wave is forecast to move eastward into the far western Indian Ocean over the next several days, favoring enhanced convection in that region. Suppressed convection is favored in the wake of both of the aforementioned Kelvin waves. Enhanced convection is forecast across much of the equatorial Pacific, supported by the model guidance and the low-frequency state. Suppressed convection is favored across parts northern South America and Central America as well as across parts of the northwestern Pacific and South China Sea. The former is supported by any remnant suppressed MJO phase, while both are supported by excellent agreement among dynamical tools. Enhanced convection is favored over the above-normal SSTs is the far eastern Pacific, while enhanced convection over the southwestern portion of Mexico is expected to extend northward into the south-central U.S. This convection is likely related to an atmospheric Kelvin wave, while the extratropical circulation is expected to be favorable for northward transport of moisture.
 

[Ed Lizard]

I guess it is good a lot of Texas will get rain, even though Houston (MBY) generally gets left out.

 

I think mention of the Ed Rule is why admin at KHOU-TV 11 weather forum stripped me of the color tag (silly, really, colors for new poster, not so new poster,  and experienced poster, I have been demoted to 'not so new poster').  That and he likes to mess with me.  Of course, he experienced hurricanes I wasn't even born for yet, so respect for the elders and all.

 

But the Ed Rule has failed only once in 2014 (the driest model always verifies best for Houston metro) and that one 3 inch rain 10 days ago was nice, but I'm not abandoning it until we get into a flood situation, at which point the wettest model will probably verify best.  Even HGX is sort of aware.

 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
343 PM CDT WED MAY 21 2014

 

.DISCUSSION...
WX SHOULD REMAIN STATUS QUO FOR THE NEXT SEVERAL DAYS WITH LOWER &
MID LEVEL RIDGES MOSTLY IN CONTROL. PW`S REMAIN FAIRLY LOW SO
DON`T ANTICIPATE MUCH IF ANY PRECIP...JUST SOME PERIODS OF LATE
NIGHT/MORNING CLOUDINESS. NEXT POSSIBLE WX MAKER WILL BE
ASSOCIATED W/ THE TROF CURRENTLY SEEN ACROSS THE WESTERN STATES.
MEDIUM RANGE SOLNS BRING HIGHER PW`S IN LATER THIS WEEKEND IN
ADVANCE OF THIS TROF AS IT APPROACHES EARLY NEXT WEEK.
TIMING/DETAILS BETWEEN THE SOLNS ARE SLIGHTLY DIFFERENT. BUT
ECMWF/GFS BOTH SHOW DECENT PRECIP COVERAGE AT TIMES DURING THE 1ST
HALF OF NEXT WEEK. THE ONGOING FCST LOOKS TO BE CLOSER TO THE
DRIER CANADIAN SOLN AND DON`T REALLY HAVE ANY REASON TO MAKE ANY
CHANGES ATTM. JUST DON`T HAVE MUCH CONFIDENCE REGARDING HOW MODELS
HANDLE THESE TYPE PATTERNS DURING THIS TIME OF YEAR AND THIS FAR
OUT. DRIER FCST HAS GENERALLY BEEN THE SAFER BET BUT AT LEAST
CHANCES APPEAR HIGHER THAN CURRENT OBSERVED WX. 47

 

[Srain]

The current slow moving long wave trough bodes well for significant rainfall across many locations across our Region that has been lacking any rain due to the long term drought. The guidance continues to advertise organized MSC event over the next 4 days across the Permian Basin and the Northern Edwards Plateau slowly extending East during the Memorial Day Weekend into early next week. The moisture tap from the Eastern Pacific and Western Gulf suggest PW's may near the 2.0 mark which is 2-3 standard deviations above normal for this time of year across the Region.

 

[Chinook]

The 12z 4km NAM suggests that 4"-6" could happen in the  area between Lubbock and Midland in the next 2 days. The regular NAM has just 1-2" from Midland up to Amarillo.

 

NOAA AHPS web site showed several areas around Lubbock and Tucumcari had over 1.5" of rain yesterday.

[Srain]

The 12z 4km NAM suggests that 4"-6" could happen in the  area between Lubbock and Midland in the next 2 days. The regular NAM has just 1-2" from Midland up to Amarillo.

 

NOAA AHPS web site showed several areas around Lubbock and Tucumcari had over 1.5" of rain yesterday.

EXCESSIVE RAINFALL DISCUSSION

NWS WEATHER PREDICTION CENTER COLLEGE PARK MD

233 PM EDT FRI MAY 23 2014

...VALID 18Z FRI MAY 23 2014 - 00Z SUN MAY 25 2014...

...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...

EAST CENTRAL TO SOUTHEASTERN NM INTO NW TX

A SLIGHT RISK AREA WAS ADDED FROM EAST CENTRAL TO SOUTHEASTERN NM

INTO NW TX AHEAD OF THE SLOW MOVING CLOSED LOW PUSHING EASTWARD

FROM THE CA/AZ BORDER EARLY THIS AFTERNOON---TO A POSITION ALONG

THE AZ/NM BORDER BY LATE SATURDAY AFTERNOON.  AN AXIS OF MUCH

ABOVE AVERAGE PW VALUES WILL CONTINUE TO STREAM NORTHWARD AHEAD OF

THIS CLOSED LOW----WITH VALUES 1-2 STANDARD DEVIATIONS ABOVE THE

MEAN PERSISTING ACROSS MOST OF THE PLAINS.  THE FOCUS FOR HEAVY TO

POTENTIALLY EXCESSIVE RAINFALL AMOUNTS ACROSS THE SOUTHERN PLAINS

WILL BE IN THE VICINITY OF THE STATIONARY FRONTAL BOUNDARY

STRETCHING FROM SW TX INTO CENTRAL OK.  MOIST SOUTHERLY LOW LEVEL

FLOW INTO THIS BOUNDARY IS CONTINUING TO FOCUS MODERATE TO HEAVY

PRECIPITATION AMOUNTS THIS AFTERNOON.  THE LATEST HI RES RUNS OF

THE ARW--NMM...CMC GEM AND NAM CONEST SHOW THIS BOUNDARY REMAINING

A FOCUS INTO TONIGHT AHEAD OF THE UPSTREAM CLOSED LOW.  WITH LOW

LEVEL INFLOW CONTINUING INTO THIS FRONT TONIGHT INTO

SATURDAY---ORGANIZED OVERRUNNING PRECIPITATION MAY CONTINUE ALONG

AND TO ITS NORTH.  AT THE SAME TIME---ADDITIONAL CONVECTION MAY

FORM OVER EASTERN NM TONIGHT AND TRACK EASTWARD ALONG AND NORTH OF

THIS BOUNDARY AHEAD OF THE UPSTREAM CLOSED LOW.  CONFIDENCE IN

DETAILS IS LOW GIVEN POOR CONTINUITY IN THE MODELS WITH THE

DETAILS.  HOWEVER---CONFIDENCE IS HIGHER THAT THE PERSISTENT

OVERRUNNING WILL SUPPORT THE POTENTIAL FOR WIDESPREAD MODERATE TO

HEAVY RAINS.  FFG VALUES CONTINUE TO LOWER ACROSS PORTIONS OF NW

TX WITH THE CURRENT RAINS AND THEY HAVE LOWERED UPSTREAM OVER

EASTERN NM FROM RAINS YESTERDAY.  WITH ADDITIONAL HEAVY RAINS

LIKELY IN THE RISK AREA---THE POTENTIAL FOR RAINFALL AMOUNTS

EXCEEDING THE LOWERING GUIDANCE WILL INCREASE WITH TIME.  ISOLATED

SHORT TERM AMOUNTS OF 1"+  AND ISOLATED TOTALS OF 3-5"+ POSSIBLE

FOR THE FORECAST PERIOD IN THE MOST PERSISTENT AREAS OF

PRECIPITATION.

 

[Srain]

The Global guidance continues to paint a very wet forecast across our Region. The shorter range High Resolution models have done rather poorly as they have initiated the heaviest rainfall too far N. The latest QPF suggest anywhere from 4-6 inches of rainfall may be possible over the next 7 days with isolated higher amounts possible where slow moving training storms develop. The long wave trough and upper low is expected to meander E into Texas on Monday and begin a slow trek SE from N Texas toward Eastern Texas and Western Louisiana by Friday before filling in and finally weakening next Saturday into Sunday. With multiple outflow boundaries present almost daily and repeating Mesoscale Convective Systems as well as the potential for a Mesoscale Convection Vortex situation developing as the upper low warms or become warmed core, the potential for heavy rainfall increases and therefore the Weather Prediction Center has placed a large portion of Central and SE Texas mainly along and N of I-10 in a Slight Risk for excessive rainfall.

 

To further complicate the forecast for the coming work week, Major Hurricane Amanda in the Eastern Pacific is now a CAT 4 and may become CAT 5 later today as it turns N and begins to finally weaken. The latest track suggests Amanda and its deep tropical moisture will move towards the NE and the SW Coast of Mexico by day 5 and could further aggravate and complicate the forecast and QPF amounts. I would not be surprised to see current Flash Flood Watches across West Central Texas and the Southern Edwards Plateau extended eastward into the San Antonio/Austin area later today and possibly shifting E into portions of SE Texas on Memorial Day and continue into Tuesday.

 

[Ed Lizard]

WPC 7 day QPF looks like Euro, but even drier GFS isn't terrible.

[Srain]

The 18Z Update issues a High Risk for excessive rainfall across portions of the Permian Basin and Northern Edwards Plateau.

[1900hurricane]

Big time rains are falling across some of the canyonlands W of San Antonio. Rainfall looks like it's very efficient too.

Sent from my iPhone using Tapatalk

[Srain]

Morning Update from Jeff Lindner (Harris County Flood Control District).

Increasing potential for heavy to excessive rainfall starting Tuesday and lasting through much of the week.

Slow moving upper level low pressure system located over the SW US which has been responsible for heavy rainfall across much of the drought plagued west TX this weekend will meander eastward and be located near Sabine Pass by late this week. Deep tropical moisture axis connected to Hurricane Amanda in the eastern Pacific is edging closer to SE TX this morning and as the upper low moves eastward should become situated across the region starting Tuesday.

 
Thus far slow moving thunderstorm complexes have remained west of our region, but this should change tonight into Tuesday as the moisture axis over central TX moves eastward along with dynamics with the upper level low. The past few days have shown very slow storm motions and cell training in a very moist “tropical” environment which has led to heavy rainfall amounts in a short period of time.
 
Rainfall Amounts:

Since this system is slow moving and has the potential to produce multiple heavy rainfall episodes over a 24-72 hour period the threat for flooding will be gradually increasing through the week as the ground saturates. The air mass is expected to become nearly saturated and tropical with moisture levels increasing to near +2 SD above normal for late May. This combined with slow storm motions and potential cell training points toward some heavy rainfall amounts.

 
Amounts will average 2-4 inches across the region with isolated totals significantly higher…possibly as much as 6-8 inches by the end of the week. This is the type of weather set up that can produce a lot of rainfall in a very short period of time. It is nearly impossible to predict where the heaviest rainfall amounts may occur especially when multiple rounds of heavy rains will occur.


Will also need to watch for the current “cold” core upper level system to attempt to transition toward a “warm” core feature as it slowly moves across a very tropical like environment. This transition would change the daily rainfall pattern away from daytime heating induced storms to more nocturnal development near/around the center of the system…or it will begin to behave very much like a dying tropical system.

[Srain]

Nearing 4 inches of rain in the gauge with this 3+ inch per hour storm complex.

[DoctorMu]

Amanda is already stoking the fire...errrrr waterhose.

 

http://www.goes.noaa.gov/GSSLOOPS/ecwv.html

 

 

This could be a substantial event...almost guaranteed because we'll be driving back tomorrow through this stuff.  So glad I turned the sprinkler system off though.  

[Ed Lizard]

None of the models, not even the 12Z 4 km NAM, picked up on the SETX happiness today.

 

Local reports confirm the rainfall amounts in metro Houston, some of the heavier amounts, maybe some hail contamination.

 

Local news damage pictures from Fort Bend County, possible that funnel cloud shown on KHOU-TV 11 touched down briefly.  A line of power poles snapped near Rosenberg and some tree/property damage, nothing too severe, although the large oak that landed on a house, that house is probably pretty damaged.

[cgidd8]

My buddy and I caught this brief spinup just west of IAH.

[Srain]

Today offers another complicated forecast. Showers and storms are developing across Metro Houston at this hour ahead of the slowly advancing line near Bryan/College Station. The upper low is spinning near Childress and continues to drift ESE. Stronger storms extend back to Junction at this hour. PW's of +2.0 Inches are in place with the Gulf open for business again after recovering from yesterday's storms. The WPC has placed a Moderate Risk for excessive rainfall from the Victoria Crossroads thru Metro Houston into Beaumont/Lake Charles and further E iinto Louisiana. As the morning continues the atmosphere should further destabilize lending to high rainfall rates on top of the 2 to 7 inches that has already fallen. The ground is saturated so additional heavy training storms will lead to flooding issues.

[Srain]

An additional 1.37 inches of rain in the gauge for a total of 5.62 inches since 4:00 PM yesterday at my location in NW Harris County.