AMS: National Meeting: Strong to severe thunderstorms / Heavy rain ?

[Martin]

Anyone else from the forums attending the meeting? 

[Srain]

Morning update from Jeff:

 

Heavy Rainfall threat increasing for Tuesday-Wednesday.

 

Powerful upper level storm system currently located inland over S CA will be moving ESE into N MX over the next 24 hours. Large scale ascent developing over TX over the next 24 hours ahead of this feature will help to induce surface pressure falls across S TX. Deepening surface low pressure over S TX will start to bring a warm front northward with this feature situated from near Port Lavaca to Bay City and then ESE into the northern Gulf of Mexico by early Tuesday. Strong 850mb low level jet will rapidly return moisture over the top of the warm front and surface cool dome resulting in the formation of light rainfall by late tonight. As large scale lift increases on Tuesday expect thunderstorms to develop along the warm front. Expect very heavy rainfall in these storms along with widespread rainfall north of the boundary to help hold the boundary roughly in place between I-10 and the coast for much of Tuesday into Tuesday night.
 
As the upper level storm ejects ENE to NE across TX on Wednesday a slow moving cool front/dry line will punch eastward into the area. While some of the models have begun to diverge some with respect to rainfall potential on Wednesday, feel that good upper level divergence on the eastern side of the upper level storm coupled with a slow moving frontal boundary will continue to produce heavy thunderstorms. Dry slot could impede development to some degree, but this feature looks aimed more at Central TX than SE TX.

 

Heavy Rainfall:
Main threat with this event will be very heavy rainfall. Models continue to show PWS climbing to over 1.7 inches which is about .25 of an inch above the +2SD for this time of year and very near the “maximum” values for early January. GPS loops of PWS over the Gulf of Mexico do suggest an area of 1.8-2.0 inch values located over the Bay of Campeche and this plume of deep moisture should become ingested into the storm system and brought northward into the area by late Tuesday. While such moisture is commonplace in the summer, it is rare in the winter when storm systems and dynamics are much stronger. The combination of such high moisture levels and strong dynamics will produce some very heavy rainfall. The air column is nearly saturated from the surface through the mid levels which will support efficient rainfall production with little evaporation leading to high short term rainfall totals. Moisture of this magnitude will support hourly rainfall totals of 1-2.5 inches.
 
Flash Flood Guidance across the region is lowest along and SE of US 59 where rains have been plentiful of late. 3-hr flash flood guidance is running around 3.0 inches. Suspect the axis of heaviest rainfall will be along and SE of US 59 (or just north of the warm frontal boundary) at least on Tuesday night. It is likely that flash flood guidance will be exceeded and significant run-off generated in this region. Rises on area bayous, creeks, and rivers is likely. Street flooding will be likely especially under areas of persistent cell training.

 

Severe Threat:
Not overly confident in a significant severe weather threat will this system as instability appears to be generally lacking south of the warm front due to widespread clouds and rainfall. Low level wind shear will be more than sufficient for storm rotation with ESE surface winds under stronger WSW mid level flow. Main threats will be wind damage and isolated tornadoes. Should the instability be slightly greater than forecast, the tornado threat would increase over the are Tuesday night and Wednesday.

 

Extended:
Much focus on the short term, but the extended does bring another wet looking system into the area by the weekend followed by a strong cold front early Sunday. Appears rains may continue after the cold front Sun-Mon. Will need to keep an eye on low temperatures by Tuesday AM if moisture is still lingering.

Severe Weather Outlook (Wednesday):

 

[Ed Lizard]

I think NAM may still be a bit too far West, based on Euro and GFS seeming to trend toward each other, but for that Texas town, with a home out on the range, you know what I'm talking about, the NAM Wednesday morning sounding looks decent.

 

 

 

January 9, 2012 small (EF-0 to EF-2 storms, and not that many) HOU area outbreak, low CAPE, apparent lack of low level instability, seemed overcome by good shear/helicity and low LCLs...

[OKpowdah]

Anyone else from the forums attending the meeting?

I am. At least a few others too

[Martin]

I am. At least a few others too

 

Awesome! Pretty good conference so far. Speakers this morning were excellent  

[CSheridan12]

I'm not a very frequent poster, more a reader (For example, I think my signature still has me as a student, but I have graduated and am now working) but I'm here! Trying to make plans for the big game tonight and also wondering if anybody knows if the harris corporation is having their annual party tonight? I'm hearing rumors of it being cancelled!

[Turtle]

Anyone else from the forums attending the meeting? 

Wish I could be there, Martin.  Don't get too wet!!    Enjoy, and learn a lot!!!

 

--Turtle

[Ed Lizard]

Even though it probably isn't quite surface based (VCT is 63º/62º w/ NE wind), if I had gone to college for a met degree (didn't) and worked at WFO CRP (don't) I'd be tempted to warn that cell based on rotation seen from HGX.

But that is just me.

 

 

ETA  It doesn't look as good the last few updated images.  Perhaps that is why the people at NWS CRP are highly paid professionals....

 

 

[OKpowdah]

www.spc.noaa.gov/products/md/md0003.html