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Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 7

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Going to bring this one over from the old thread if that's ok:

 

The MJO might not verify to that insane magnitude, but a powerful wave is certainly coming. Tropical forcing is currently out of this world thanks in part to 93P, which is actually in the southern hemisphere but convection associated with the complex extends across both hemispheres. All this equatorial divergence aloft is really going to foster one killer MJO wave.

 

troppac_latest.gif

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The trends today continue to increase our chances of an active weather pattern particularly along and South of Central Texas from about Corpus Christi to New Orleans. The 5 Day QPF (Quantitative Precipitation Forecast) from the various reliable computer guidance remain in excellent agreement suggesting deep tropical moisture with its origin beyond Hawaii in the Pacific Ocean extending East toward the Baja Peninsula will cross Mexico and a Coastal trough begins  organizing tomorrow afternoon as embedded disturbances ride ENE across Mexico, Texas and Louisiana. There continues to be some uncertainty regarding the late next week timeframe as the same basic weather pattern looks to remain unchanged meaning we could see rainfall chances, sometimes heavy continue beyond Tuesday. Flash Flood guidance remains rather high, but if training elevated storms develop, the Flash Flood threshold could be met and possibly exceeded. Time to keep an eye on the weather once again and this time it will not be of a wintry nature.

 

sat_wv_hem_loop-12.gif

 

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Really looking forward to this rain. Guidance has me pretty close to the max swath of around 4", which I would be ecstatic to receive. Although I wish it were convective (I may be getting a little impatient for severe weather season :P), I'll be happy with rain of any fashion of over 2". More than that would be icing on the cake.

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HGX will likely hoist a FFW this afternoon as the Coastal trough organizes near Corpus to Matagorda and dewpoints increase along and S of the I-35 Corridor as well as areal coverage of elevated storms ramp up.

 

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
957 AM EDT SUN MAR 08 2015

...VALID 15Z SUN MAR 08 2015 - 12Z MON MAR 09 2015...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
15 E KRP 15 SSW NGP 20 S NQI 15 S BKS 25 SSW BKS 30 SW BKS
20 NNW HBV 40 W COT 35 ESE MMPG 15 NW UVA T82 10 NW GTU
20 ESE TPL 15 NNE LHB 40 NW UTS 20 NNW UTS 20 NNE UTS 25 SSW LFK
35 S LFK 45 E CXO 40 ENE IAH 10 ESE PSX 20 S PSX 15 E KRP.


TEXAS HILL COUNTRY TOWARD THE TEXAS GULF COAST

CONCERNS FOR POTENTIAL VERY HEAVY RAINFALL AMOUNTS THIS UPCOMING
PERIOD FROM THIS TX HILL COUNTRY TOWARD THE TEXAS GULF COAST AHEAD
OF THE EASTWARD MOVING CLOSED LOW ACROSS NORTHERN MEXICO.
STRENGTHENING SOUTHERLY LOW LEVEL FLOW OFF THE WESTERN GULF AHEAD
OF THIS CLOSED LOW WILL BE RAISING PW VALUES TO 1 TO 2 STANDARD
DEVIATIONS ABOVE THE MEAN ACROSS A LARGE PORTION OF TEXAS INTO THE
LOWER MS VALLEY.  PRECIPITATION SHOULD CONTINUE TO EXPAND IN
COVERAGE EARLY THIS MORNING FROM SOUTH TEXAS---EAST NORTHEASTWARD
INTO THE LOWER MS VALLEY ASSOCIATED WITH LEAD AREAS OF SHORTWAVE
ENERGY EJECTING AHEAD OF THE UPSTREAM CLOSED LOW.  CONFIDENCE IN
QPF DETAILS WITH THE LEAD HEIGHT FALLS IS LOW GIVEN THE LARGE
SPREAD IN DETAILS MODEL TO MODEL AND MODEL RUN TO RUN.  TOWARD THE
END OF THIS FORECAST PERIOD---SUNDAY NIGHT INTO EARLY MONDAY
MORNING---CONVECTION SHOULD BECOME BETTER ORGANIZED AS THE
UPSTREAM CLOSED LOW PUSHES EASTWARD.  ADDITIONAL STRENGTHENING OF
THE SOUTHERLY LOW LEVEL FLOW IN A REGION OF FAVORABLE UPPER
DIFFLUENCE IN THE RIGHT ENTRANCE REGION OF THE UPPER JET SHOULD
SUPPORT POTENTIAL OF A WELL ORGANIZED AREA OF CONVECTION FROM IN
THE VICINITY OF THE HILL COUNTRY OF SOUTH TX--EAST NORTHEASTWARD
TOWARD THE TX GULF COAST. MODEL QPFS AT THIS TIME ARE IN BETTER
AGREEMENT---WITH BETTER CONFIDENCE IN HEAVY PRECIPITATION
POTENTIAL AT THIS TIME.   ALTHOUGH FFG VALUES ARE CURRENTLY
HIGH---THEY  MAY LOWER DURING THE FIRST HALF OF THIS PERIOD WITH
THE LEAD AREA OF HEIGHT FALLS.  WITH ORGANIZED CONVECTION THEN
POSSIBLE SUNDAY NIGHT INTO EARLY MONDAY---RUNOFF ISSUES MAY
DEVELOP FROM THE TX HILL COUNTRY EASTWARD TO THE TX GULF COAST
FROM THE ADDITIONAL HEAVY RAINFALL.

ORAVEC

 

 



 

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too bad we can't get those kinds of rains NW of DFW... yeah we've had a lot of moisture and are 2"+ above normal, however every good rainstorm we get now to help fill those lakes a bit means it gives us more buffer room if the summer gets to be as dry as last summer was

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Need it up here, but hopefully will get our turn later. Regardless, some rain is coming at least. Good stuff for down south though! They need it as well.

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2.43 inches in the my gauge since this event began and counting. Moderate rain has began across NW Harris County and the radar is a sight we have not seen in a long time across our Region.

 

southplains_loop.gif

 

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HGX and EWX radars estimate that there has been between 2 and 5" between Houston and San Antonio, as well as north of Houston.

Looks like about an inch and a half here in Austin so far. Rain's generally been light but we've had some moderate bursts. The main heavy rain axis looks to have set up east of here but it's still definitely good for the lakes, since we haven't had a soaking rain in a while.

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From Nesdis:

 

SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 03/09/15 1941Z
SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-683-1404
LATEST DATA USED: GOES-13 1930Z KUSSELSON
NOAA AMSU: 1650Z 1556Z  DMSP SSMIS:1456Z
.
LOCATION...SE TEXAS...
.
ATTN WFOS...LCH...SHV...HGX...FWD...
ATTN RFCS...WGRFC...
.
EVENT...VERY HIGH MOISTURE..SHORT WAVE AND WEAK DIFFLUENCE...RATHER
STRONG UPPER LEVEL DIVERGENCE FOR LOCALLY HVY RAIN IN RATHER LOW FF
GUIDANCE AREAS...
.
SATELLITE ANALYSIS AND TRENDS...DEEP MOISTURE PLUME IN PLACE WITH TROPICAL
EASTERN PACIFIC ORIGINS THAT HAVE EASILY MADE IT OVER THE MEXICAN
MOUNTAINS.  NOSE OF HIGHEST MOISTURE HAS STRADDLED THE TEXAS COAST OR
THE FAR WESTERN GULF AND AS FAR NORTH AS THE TEXAS/SW LA BORDER AREA...SO
CERTAINLY SUFFICIENT DEEP UNUSUALLY HIGH MOISTURE FOR THIS TIME OF YEAR
WITH A EAST PACIFIC TROPICAL CONNECTION.  NOW, WHETHER THERE IS ENOUGH
LIFT IS DEBATABLE...BUT WEAK DIFFLUENCE SEEN ON GOES WATER VAPOR LOOP,
ESPECIALLY JUST INLAND FROM THE COAST.  MORE IMPRESSIVE MODERATE UPPER
LEVEL DIVERGENCE SEEN MID TX COAST TO JUST INLAND.   MODERATE LOOKING
SHORT WAVE TROUGH WAS LIFTING NORTHEAST ACROSS SOUTH CENTRAL TO CENTRAL
TEXAS AND WILL AID IN PROVIDING ADDED LIFT.  ON TOP OF ALL THAT WAS
CONTINUED DEEP 700-500MB MID LEVEL MOISTURE BEING PUMPED IN FROM THE
TROPICAL EASTERN PACIFIC AS PER LATEST EXPERIMENTAL LAYER PW PRODUCT AT:
http://cat.cira.colostate.edu/sport/layered/blended/lpw.htm   AND FF
GUIDANCE RATHER LOW IN AND AROUND THE HOUSTON AREA AND A LITTLER HIGHER
SOUTHWEST OF HOUSTON TO JACKSON COUNTY.  AND WITH PWATS CLOSE TO 1.95"
AROUND PORT ARANSAS GPS SITE...COULD BE JUST ENOUGH TO HEIGHTEN FF THREAT
ESPECIALLY IN THOSE LOW GUIDANCE AREAS.

 

SHORT TERM OUTLOOK VALID 1945-2245Z...MEDIUM CONFIDENCE FACTOR
IN SHORT TERM OUTLOOK...CONSIDERING RAINFALL AMOUNTS OF THE PAST 24 TO
36HRS AND LIFT AND MOISTURE MENTIONED IN ABOVE ANALYSIS AND CONTINUING
OVER SE TEXAS...THERE COULD BE ENOUGH RAINFALL TO RESULT IN LOCALIZED
PROBLEMS, ESPECIALLY OF THE URBAN TYPE LATER HALF OF PERIOD FOR THE
HOUSTON AREA AND MAYBE EARLIER IN THE COUNTIES TO THE SOUTHWEST OF HOUSTON
JUST INLAND FROM THE COAST.   NOT EXPECTING MUCH IF ANY CONVECTION...BUT
CERTAINLY ENOUGH WARM CLOUD TOP CONVECTIVE-LIKE ELEMENTS OF SATELLITE
THAT IF THEY CAN ORGANIZE A BIT MORE COULD CONTINUE TO SHIFT HEAVY RAIN
BANDS FURTHER NORTHEAST TOWARD HOUSTON IN THE NEXT 3HRS.

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The MJO wave will reach record levels when it peaks at phase 7...this will keep the Pacific hose in high year. It will keep a good deal of amplitude while translating to phase 8. This latter phase will allow a mean trough a little farther east, allowing cold highs to dive south. This has already been advertised by guidance at days 8+, when the EPO goes negative once more, but this time aided by a possible -AO.

 

An MJO amplitude > 3 is being advertised by reliable guidance

post-29-0-19706300-1426018613_thumb.gif

 

The reason is the strong  low level forcing near the dateline which is around -5 STD for 200mb VP anomalies

post-29-0-37614200-1426018651_thumb.png

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Didn't really expect that much rain today. Forecasts were around 0.2 to 0.4"...currently at 1.25" and still raining moderately (0.5"/h). Had lightning/thunder...pretty awesome considering the average for March IMBY is 0.8". That's the unpredictability factor of an ULL.

 

Forecasts for huge parts of the Sierra between Durango and Mazatlan are currently showing > 20" of snow, with >40" showing up in the latest forecasts...Also a huge part of central MX is being shown with > 5" of precip, and as high as 15"...that's really something as we are in the dry season.

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Didn't really expect that much rain today. Forecasts were around 0.2 to 0.4"...currently at 1.25" and still raining moderately (0.5"/h). Had lightning/thunder...pretty awesome considering the average for March IMBY is 0.8". That's the unpredictability factor of an ULL.

 

Forecasts for huge parts of the Sierra between Durango and Mazatlan are currently showing > 20" of snow, with >40" showing up in the latest forecasts...Also a huge part of central MX is being shown with > 5" of precip, and as high as 15"...that's really something as we are in the dry season.

 

Nice!

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The MJO wave will reach record levels when it peaks at phase 7...this will keep the Pacific hose in high year. It will keep a good deal of amplitude while translating to phase 8. This latter phase will allow a mean trough a little farther east, allowing cold highs to dive south. This has already been advertised by guidance at days 8+, when the EPO goes negative once more, but this time aided by a possible -AO.

 

An MJO amplitude > 3 is being advertised by reliable guidance

attachicon.gifALL_emean_phase_full (1).gif

 

The reason is the strong  low level forcing near the dateline which is around -5 STD for 200mb VP anomalies

attachicon.giftwc_globe_mjo_vp200.png

 

I am starting to like the window b/w March 18 - 22 for a shot at some more Texas snow.  Probably the Panhandle back to the moutains of New Mexico but I wouldn't totally rule out one last north of I-20 special. 

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Guidance is beginning to latch onto a very southerly closed low or cutoff by the tip of Baja. I'm thinking rain futures look good once again a week or so out as this system comes back north into the main flow, dragging rich tropical pacific moisture aloft with it.

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Morning briefing from Jeff:

 

Additional rainfall likely this afternoon into early Thursday over the eastern ½ of the region.

 

Upper trough nearly stationary from the central plains to northern MX continues to produce a favorable upper level pattern for the development of western Gulf of Mexico surface low pressure systems. Satellite and radar data indicate that a new surface low has formed over the west-central Gulf of Mexico this morning with a significant increase in convection around this feature (good thing it is not July). This surface low if forecast to track NNE today and landfall along the extreme SE TX or SW LA coast tonight. Expect light to moderate rains to develop offshore this morning and gradually spread inland late this afternoon into this evening as the surface low approaches. Will confine the highest rainfall totals along and east of I-45 where up to another .5-1.0 inch of rain may fall tonight into early Thursday.

 

Areas west of I-45 which were hard hit early this week with rainfall should see the lowest amounts and areas around College Station may not see any additional rainfall at all.

 

Upper trough over northern MX breaks apart and retrogrades (moves westward) late this week into this weekend allowing high pressure to finally take hold over TX with clearing skies and low rain chances Friday-Sunday. However rainfall looks to return early next week yet again as this system begins to finally push eastward toward the state.

 

Hydrology:

 

Several rivers and watersheds are in flood or are forecast to rise into flood over the next few days as run-off from the widespread heavy rainfall early this week translates downstream. Flood gate operations are ongoing at both Lake Conroe and Lake Livingston and this is resulting in downstream rises on both the San Jacinto and Trinity Rivers.

 

Navasota River: river is above moderate flood level at Easterly and forecast to rise above flood stage and to near moderate flood levels at Normangee this Friday. The river will remain above flood stage through this weekend.

 

Brazos River: river is rising at all points and forecast to rise above flood stage at Rosharon this weekend. No flooding is currently expected at Bryan, Hempstead, or Richmond.

 

Trinity River: river is rising and will rise above flood stage at Liberty this weekend and hold near moderate flood levels for several days due to upstream releases from Lake Livingston. Some subdivisions near the river in Liberty County may become cut-off. River is above flood stage at Riverside above Lake Livingston and is forecast to remain above flood stage through this weekend.

 

San Bernard River: river is above flood stage at East Bernard and continues a steep rise. Current forecast does not match the river trends and expect a higher crest that being forecast considering eh river is already about a foot over the forecast. Secondary rise will begin at Boling and given the upstream response ongoing, Boling may rise back above flood stage late this week.

 

West Fork of the San Jacinto River: Lake Conroe is currently releasing 6300 cfs and this along with inflow from Lake Creek is resulting in elevated levels at Porter. The river is forecast to rise to near flood stage at Porter. The river is falling at Humble and should continue a slow fall. Lake Houston appears to be near peak with about 1.5ft of water going over the spillway.

 

Colorado River: river is below flood stage at all points. Initial flood wave has reached Wharton with a secondary flood wave having passed Smithville overnight with Columbus starting a secondary rise within the last few hours. All stages should remain within banks.

 

Guadalupe River: river is above flood stage at Bloomington and will remain above flood stage through this weekend.  

 

For current and forecasted river levels please visit the following website: http://water.weather.gov/ahps2/index.php?wfo=hgx

 

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From Nesdis regarding the Western Gulf Low developing:

 

SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 03/11/15 1935Z
SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-683-1404
LATEST DATA USED: 1915Z  HANNA
.
LOCATION...LOUISIANA...TEXAS...
.
ATTN WFOS...LIX...LCH...HGX...
ATTN RFCS...LMRFC...WGRFC...
.
EVENT...SATELLITE FEATURES FOR DEVELOPING LOW IN W GULF
.
SATELLITE ANALYSIS AND TRENDS...WATER VAPOR IMAGERY SHOWED LARGE SCALE
PATTERN TO HAVE AN ANOMALOUS MID LEVEL TROF FROM THE S CNTRL STATES
EXTENDING S TO THE SUBTROPICAL E PAC.  SHORTWAVE IMPULSE WAS EJECTING
OUT OF THE BASE OF THE TROF IN RESPONSE TO A STRONGER UPSTREAM IMPULSE
AMPLIFYING AND CLOSING OFF OVER W CNTRL MX.  THE EJECTING DOWNSTREAM
IMPULSE HAS BEEN SHOWING SIGNS OF CLOSING OFF IN THE MID LEVELS AS A
COMMA HEAD HAS BEGUN TO DEVELOP OVER THE PAST FEW HOURS IN RESPONSE TO
A MID LEVEL JET STREAK LIFTING N THROUGH THE W GULF.  THIS WOULD IMPLY
CYCLOGENESIS SHOULD CONTINUE JUST E OF THE COMMA HEAD NEAR 26N/94W AS
SYSTEM CONTINUES TO DEVELOP N THROUGHOUT THE AFTERNOON AND INTO THE
EVENING.  SURFACE/SHIP/BUOY OBSERVATIONS ALONG WITH MOST RECENT METOP
ASCAT PASS INDICATE THAT SYNOPTIC BOUNDARY WAS SITUATED FROM ROUGHLY THE
MOUTH OF THE MS RIVER EXTENDING SW TOWARDS W GULF SURFACE LOW.  HEAVIEST
RAINFALL HAS BEEN CONFINED TO NEAR BETTER GOES SOUNDER INSTABILITY AXIS
ALONG FRONTAL BOUNDARY BUT LIGHT TO MODERATE RAINFALL HAS BEEN APPROACHING

COASTAL AREAS WITHIN AREA OF DEFORMATION AND ALONG THE LEADING EDGE OF
STRENGTHENING LOW LEVEL FRONTOGENESIS N/NW OF SYSTEM. PROXIMITY TO LOW
LEVEL BOUNDARY AND INSTABILITY AXIS SHOULD ALLOW FOR THE POTENTIAL FOR
LOCALIZED HEAVY RAINFALL THREAT TO BEGIN APPROACHING PORTIONS OF SE LA
OVER THE NEXT FEW HOURS.  BEYOND THAT, AS MID LEVEL JET STREAK CONTINUES
TO LIFT N OVER THE W GULF THROUGHOUT THE AFTERNOON AND INTO THE EVENING
IT SHOULD BEGIN TO COUPLE WITH DOWNSTREAM JET STREAK NEAR CREST OF MID
LEVEL RIDGE AXIS.  THE LOW LEVEL RESPONSE TO THIS AND DECREASING HALF WAVE
LENGTH BETWEEN SHORTWAVE TROF AND RIDGE SHOULD BE A STRENGTHENING SE LLJ
NEAR REGION OF ANOMALOUS MOISTURE OVER THE NW GULF ON LATEST BLENDED
PW ANALYSIS.  THIS SHOULD ALLOW FOR AN ENHANCED AREA OF INTEGRATED
MOISTURE TRANSPORT AND LOW LEVEL FRONTOGENESIS OVER REMNANT SYNOPTIC
BOUNDARY TO DEVELOP N/NW TOWARDS COASTAL LOCATIONS OF SW LA/SE TX DURING
THE EVENING HOURS SPREADING LOCALIZED HEAVY RAIN THREAT INTO THIS REGION.
SEE JUST ISSUED QPFERD AND QPFPFD FOR ADDITIONAL INFORMATION.

 

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The NAM variants have been way further west with the axis of heaviest precip (like over my head instead of over towards the Sabine) today to the point where I was considering them outliers. However, based on the latest radar trends, maybe it was on to something...

 

Definitely a tricky forecast tonight. Looks like obs and radar trends are going to to a better job than relying on guidance.

 

HGX_loop.gif

 

rad8.gif

 

ptot60.gif

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And now the 00Z NAMs are coming out just in time to crush my rainfall dreams. Oh well... :P

 

I went from over an 1" at 18z to sprinkles at 00z  :lol:  The western edge is always a bad place to be, luckily this isn't winter weather or I would be pulling my hair out!

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Good QPF total on the 12 GFS, so sure hope that verifies. We really need 3 inches of rain over N. Texas, especially west of FW. But, color me skeptical....

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