August - Warm and Dry Weather Returns To End The Month

[srainhoutx]

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
439 PM EDT FRI AUG 23 2013


PRELIM DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID AUG 24/0000 UTC THRU AUG 27/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR

...DAYS 2/3...

...GULF COAST...

A WELL DEFINED WAVE WILL CONTINUE TO MOVE WEST ALONG AN OLD
FRONTAL BOUNDARY ACROSS THE GULF OF MEXICO DURING DAYS 2 AND 3.
THERE WAS GOOD AGREEMENT AMONG THE 12Z MODEL SUITE MEMBERS
CONCERNING THE SYNOPTIC SETUP...AND THE QPF WAS DERIVED FROM A 12Z
ECMWF/GFS/09Z SREF BLEND.

THE WAVE MOVES WEST TO NEAR THE LA/TX BORDER BY THE END OF DAY 2.
ALONG THE PATH OF THE WAVE...PRECIPITABLE WATER SHOULD REMAIN NEAR
2.25 INCHES (WHICH IS TWO STANDARD DEVIATIONS ABOVE NORMAL). THE
HIGH MOISTURE CONTENT AIR WILL FUEL DEVELOPING CONVECTION...WHICH
WILL RECEIVE LOCAL SYNOPTIC SCALE LIFT FROM WEAK SHORT WAVES IN
THE EASTERLY FLOW SOUTH OF A BUILDING MID LEVEL RIDGE. MODEL
SOUNDINGS SHOW MODERATE INSTABILITY WITH A CONSISTENT SOUTHEAST
INFLOW...AND THE CONVECTIVE CLUSTERS THAT DEVELOP SHOULD PRODUCE A
STRIPE OF 0.25 TO 0.50 INCHES OF QPF ALONG THE IMMEDIATE COAST
FROM WESTERN FL INTO SOUTHEAST TX.

THE WAVE MOVES INLAND ACROSS SOUTHEAST TX DURING DAY 3. WEAK SHORT
WAVES MOVING TO THE SOUTHEAST TX COAST WILL PROVIDE LIFT FOR
CONVECTION IN THE HIGH MOISTURE CONTENT AIR. THIS SHOULD
CONCENTRATE THE QPF ACROSS SOUTHERN TX...WITH THE HIGHEST
AMOUNTS...NEAR AN INCH...ACROSS SOUTHEAST TX.

[srainhoutx]

Right on cue, a rather impressive Kelvin Wave and MJO pulse are nearing the Western North Atlantic Basin and two wave axis are approaching each other with one heading NW from the NW Caribbean and the second moving W bound across the Central Gulf. Deep tropical convection is associated with the wave axis crossing the Yucatan at this hour.

[rnmm]

Right on cue, a rather impressive Kelvin Wave and MJO pulse are nearing the Western North Atlantic Basin and two wave axis are approaching each other with one heading NW from the NW Caribbean and the second moving W bound across the Central Gulf. Deep tropical convection is associated with the wave axis crossing the Yucatan at this hour.

What will this mean as far as weather goes?

[SusieinLP]

I was hoping formore than an inch.... Don't these blobs usually dump some heavy tropical rains?? Oh well....

Just a question. Isn't this in the same area Alicia formed? Not expecting or wishing for another Alicia...just curious

[srainhoutx]

Right on cue, a rather impressive Kelvin Wave and MJO pulse are nearing the Western North Atlantic Basin and two wave axis are approaching each other with one heading NW from the NW Caribbean and the second moving W bound across the Central Gulf. Deep tropical convection is associated with the wave axis crossing the Yucatan at this hour.

What will this mean as far as weather goes?

Generally this would suggest increased tropical convection with rising air and lowering pressures across the Gulf and Caribbean and then further E towards the MDR (Main Development Region) which is E of the Caribbean Islands.

[Texas Pirate]

Right on cue, a rather impressive Kelvin Wave and MJO pulse are nearing the Western North Atlantic Basin and two wave axis are approaching each other with one heading NW from the NW Caribbean and the second moving W bound across the Central Gulf. Deep tropical convection is associated with the wave axis crossing the Yucatan at this hour.

I wish there were a LIKE button on here....RAIN!

[jasons2k]

Seems like to me that you don't understand the forecast. 30% chance of rain means there is a 70% chance it will not rain...not sure why you are expecting so much rainfall from lower chances.

Jeff, as you know I highly respect your opinions. But in fairness to the poster, there is more to the story than just the pop numbers published by the NWS. It bothers me when the NWS falls back to "well the POPs only said this", when there were many discussions to put those numbers into context.

The discussions from last weekend and earlier this week certainly inferred more coverage than the pretty pitiful amount of rain we have seen this week. The discussions said while the pops were held where they were (and it was 40% yesterday), it was a matter of timing the waves and they would be adjusted up and down accordingly. The problem is the increased coverage they were expecting by Tuesday, then by Wednesday, then finally-we-mean-it-now by Thursday never materialized.

Also, at one time (Sun or Mon?) the NWS did get pretty specific in an AFD and said while not all locations would see rainfall on each day (clarifying the POP numbers), they did say generally an inch+ would accumulate along and south of the I-10 corridor this week, and up to an inch north of I-10 with locally higher amounts. There was one discussion inferring that even though this was not going to be a drought buster, this was definitely going to start a trend in the right direction and put a dent in the rainfall deficit..then there was the subsequent pasting of all the climate data and rainfall deficits to date at the bottom of the AFD.

The NWS doesn't do that in all their discussions. They only do that when they expect a significant weather event to have some sort of impact on said posted climate information. So to say 'the pops were only in the 30-40% range so why were you expecting it to rain?' is not exactly fair IMHO.

[skidog40]

these storms are about to merge.

[txflagwaver]

Jason...that is why I just finished watering my yard. I hope it rains...but lately whenever a lot of rain is expected it just simply does not happen. No one fault...it's weather.

[txflagwaver]

I was hoping formore than an inch.... Don't these blobs usually dump some heavy tropical rains?? Oh well....

Just a question. Isn't this in the same area Alicia formed? Not expecting or wishing for another Alicia...just curious

Similar in location to Alicia http://www.wunderground.com/hurricane/a ... ane-Alicia

The low that became Alicia formed from a mesoscale convective system that developed on the tail end of a frontal zone just offshore the central Gulf coast. The system moved around the southwest periphery of the subtropical ridge and intensified
at the rate of one millibar per hour into a tropical storm on the 15th and a hurricane on the 16th. As the
ridge moved eastward, Alicia turned northwest to the west of Galveston and Houston, Texas as a category 3 hurricane. Helping to break drought conditions across the southern Plains, Alicia dropped moderate to heavy rains across portions of Texas and Oklahoma before its surface circulation began to open up across the central Plains on the 20th.

[robertscottlazar]

jeff wrote:
Seems like to me that you don't understand the forecast. 30% chance of rain means there is a 70% chance it will not rain...not sure why you are expecting so much rainfall from lower chances.
jeff with all due respect the forecast turned out to be wrong. the increased coverage never materialized,as jason said. i know what i saw on david pauls forecast. his futurecast was wrong.
the rainfall % chances should have been 5-10% not 40%. and i stand by that. i wasnt expecting a ton of rain,sir. i was expecting the forecast to pan out as it was being shown. that didnt happen. i think it was tuesday evening when david paul showed futurecast having scatterred showers all over the area for the next day. he said the people who didnt get it the day before would get it tomorrow. that didnt happen. the radar for that day wasnt showing hardly any showers at all. futurecast was full of showers. the forecast was wrong. and if calling that out upsets some people so bet it.

[Rip76]

It's amazing how it just clears out from Galveston and toward the northwest.
As if droughts, breed droughts...

[SusieinLP]

Neither of those blobs look very impressive to me. Hope one of them gives us some rain but I'm watering my yard tomorrow morning anyway. txflagwaver, thanks for the info.. I'm ok with a blob fizzling out rather than exploding into a strong storm but it would be nice to get a few days of steady rains to really soak in to the ground.

[Belmer]

jeff wrote:
Seems like to me that you don't understand the forecast. 30% chance of rain means there is a 70% chance it will not rain...not sure why you are expecting so much rainfall from lower chances.
jeff with all due respect the forecast turned out to be wrong. the increased coverage never materialized,as jason said. i know what i saw on david pauls forecast. his futurecast was wrong.
the rainfall % chances should have been 5-10% not 40%. and i stand by that. i wasnt expecting a ton of rain,sir. i was expecting the forecast to pan out as it was being shown. that didnt happen. i think it was tuesday evening when david paul showed futurecast having scatterred showers all over the area for the next day. he said the people who didnt get it the day before would get it tomorrow. that didnt happen. the radar for that day wasnt showing hardly any showers at all. futurecast was full of showers. the forecast was wrong. and if calling that out upsets some people so bet it.

You should boycott this forum and teach David Paul a lesson!

AZ...it doesn't work like that. Just because one location receives rain one day, doesn't mean the people who missed out will see rain the next. If only weather was that simple. If you really really want rain, hide from this forum for another day, because it will be like what's been going on all week. But I'm almost sure you will see at least one rain drop in your neighborhood between Sunday morning-Monday evening.

Ed....

[unome]

on overly-optimistic blog from Eric Berger - a few inches across Houston Metro ???

http://blog.chron.com/weather/2013/08/g ... anization/


HGX looks more realistic:

[jasons2k]

Interesting tidbit in today's NWS discussion. Even they admit they got 'burned' by these recent rainfall events:

MODELS SUGGEST MORE PRECIP COVERAGE FURTHER INLAND THAN I WOULD`VE SUSPECTED ESP CONSIDERING THE FCST STRENGTHENING OF THE MID LEVEL RIDGE EXTENDING DOWN INTO THE REGION FROM THE PLAINS.

WILL HESITANTLY CONTINUE ADVERTISE CHANCE POPS ACROSS NRN AREAS FOR NOW...BUT HAVE BEEN BURNED IN THESE SIMILAR PATTERNS IN PAST WITH PRECIP HANGING CLOSER TO THE COAST.

Anyway, the blob looks decent this morning. Not expecting development but I think it just might give us decent rain coverage.

[Rip76]

I DEMAND, just kidding.

Sprinklers going strong.

[robertscottlazar]

i have a prediction. on sunday i think the area doesnt receive the 60% chance of rain that is being forecasted. i bet we come out of this "wetter" pattern with nothing. the forecasting has been pretty pathetic.

[Rip76]

If you look closely, at the end of this loop.
Is that violet/pink color dry air coming out of the Dallas area?

[srainhoutx]

If you look closely, at the end of this loop.
Is that violet/pink color dry air coming out of the Dallas area?

That is subsidence that was expected ahead of the trough axis across the N Central Gulf Coast and a stalled out frontal boundary well to our N. If you notice on a wider view from GOES E Water Vapor, the area associated with 95L is developing an upper anti cyclonic Ridge aloft which is favorable for some development once it enter the Bay of Campeche allowing for ventilation and the driest of air is off to our ENE across the Ohio/Tennessee Valley Region associated with the Eastern trough.