2008 Severe Weather Thread

[RL3AO]

Lets see. The global temp was below average in January for the first time since November 2000. We are possibly looking at a 3rd severe weather outbreak in a little over a month. It is amazing how cold waters in the Pacific can cause the global climate to change...even if only for a few months.

[Ed Mahmoud]

Relative shear 400 m2/s2? Is it just me, or does that sound insanely high?

GFS forecast sounding for noon at Conroe is 559m^2s^-2

[r22weiss]

GFS forecast sounding for noon at Conroe is 559m^2s^-2

That is insanely high! But makes sence as Conroe is closer to the warm front at Noon.

[RL3AO]

2 high risk days in February would be disturbing.

This is also strange to say the least.

2004 vs 2008
Number of tornadoes
2004: 1819 (all-time record)
2008: 168 confirmed

2004: 66 deaths
2008: 66 deaths

2004: 5 F4s
2008: 5 EF4s

[Ed Mahmoud]

Relevant snip of NWS HGX AFD

FOR TOMORROW THE THREAT OF SEVERE WEATHER REMAINS SIGNIFICANT FOR
ALL OF SE TX. THE APPROACHING UPPER LEVEL LOW/TROF TO HAVE A GOOD
DEAL TO WORK WITH AS THE AIRMASS OVER SE TX IS PROGGED TO BE VERY
MOIST AND UNSTABLE. MODEL SOUNDINGS INDICATING HIGH PWS (AOA 1.6-
1.8") AND HELICITIES (+400M2/SEC2)...AND VERY LOW LI (-6/-8). NAM
ALSO HAS EHI NUMBERS PEAKING NEAR 3 OVER THE WRN PARTS OF OUR CWA
AROUND NOON. SO THE EXPECTED SCENARIO HAS SCATTERED/DISCRETE TSRA
DEVELOPING OVER THE CWA FROM LATE MORNING THROUGH THE AFTN HOURS.
WE WILL THEN SEE A SQUALL LINE ASSOCIATED WITH THE UPPER LOW/PAC-
IFIC FRONT DEVELOP OUT WEST AND SWEEP ACROSS THE STATE DURING THE
LATE AFTN/EARLY EVENING. TSRAS DURING THE AFTN HAVE THE POTENTIAL
TO PRODUCE TORNADOES ALONG WITH HAIL...STRONG WINDS AND HVY RAIN.
HVY RAINS AND DAMAGING WINDS TO ACCOMPANY THE SQUALL LINE. THREAT
OF FLOODING NOT QUITE AS ELEVATED AS THE SEVERE WX THREAT ATTM AS
PROGGED STORM MOTIONS ARE DECENT. ADDITIONAL DETAILS CAN BE FOUND
VIA SPC OUTLOOKS FOR DAY 1 AND DAY 2.

[srainhoutx]

Relevant snip of NWS HGX AFD

FOR TOMORROW THE THREAT OF SEVERE WEATHER REMAINS SIGNIFICANT FOR
ALL OF SE TX. THE APPROACHING UPPER LEVEL LOW/TROF TO HAVE A GOOD
DEAL TO WORK WITH AS THE AIRMASS OVER SE TX IS PROGGED TO BE VERY
MOIST AND UNSTABLE. MODEL SOUNDINGS INDICATING HIGH PWS (AOA 1.6-
1.8") AND HELICITIES (+400M2/SEC2)...AND VERY LOW LI (-6/-8). NAM
ALSO HAS EHI NUMBERS PEAKING NEAR 3 OVER THE WRN PARTS OF OUR CWA
AROUND NOON. SO THE EXPECTED SCENARIO HAS SCATTERED/DISCRETE TSRA
DEVELOPING OVER THE CWA FROM LATE MORNING THROUGH THE AFTN HOURS.
WE WILL THEN SEE A SQUALL LINE ASSOCIATED WITH THE UPPER LOW/PAC-
IFIC FRONT DEVELOP OUT WEST AND SWEEP ACROSS THE STATE DURING THE
LATE AFTN/EARLY EVENING. TSRAS DURING THE AFTN HAVE THE POTENTIAL
TO PRODUCE TORNADOES ALONG WITH HAIL...STRONG WINDS AND HVY RAIN.
HVY RAINS AND DAMAGING WINDS TO ACCOMPANY THE SQUALL LINE. THREAT
OF FLOODING NOT QUITE AS ELEVATED AS THE SEVERE WX THREAT ATTM AS
PROGGED STORM MOTIONS ARE DECENT. ADDITIONAL DETAILS CAN BE FOUND
VIA SPC OUTLOOKS FOR DAY 1 AND DAY 2.

Wow

[srainhoutx]

Relevant snip of NWS HGX AFD

FOR TOMORROW THE THREAT OF SEVERE WEATHER REMAINS SIGNIFICANT FOR
ALL OF SE TX. THE APPROACHING UPPER LEVEL LOW/TROF TO HAVE A GOOD
DEAL TO WORK WITH AS THE AIRMASS OVER SE TX IS PROGGED TO BE VERY
MOIST AND UNSTABLE. MODEL SOUNDINGS INDICATING HIGH PWS (AOA 1.6-
1.8") AND HELICITIES (+400M2/SEC2)...AND VERY LOW LI (-6/-8). NAM
ALSO HAS EHI NUMBERS PEAKING NEAR 3 OVER THE WRN PARTS OF OUR CWA
AROUND NOON. SO THE EXPECTED SCENARIO HAS SCATTERED/DISCRETE TSRA
DEVELOPING OVER THE CWA FROM LATE MORNING THROUGH THE AFTN HOURS.
WE WILL THEN SEE A SQUALL LINE ASSOCIATED WITH THE UPPER LOW/PAC-
IFIC FRONT DEVELOP OUT WEST AND SWEEP ACROSS THE STATE DURING THE
LATE AFTN/EARLY EVENING. TSRAS DURING THE AFTN HAVE THE POTENTIAL
TO PRODUCE TORNADOES ALONG WITH HAIL...STRONG WINDS AND HVY RAIN.
HVY RAINS AND DAMAGING WINDS TO ACCOMPANY THE SQUALL LINE. THREAT
OF FLOODING NOT QUITE AS ELEVATED AS THE SEVERE WX THREAT ATTM AS
PROGGED STORM MOTIONS ARE DECENT. ADDITIONAL DETAILS CAN BE FOUND
VIA SPC OUTLOOKS FOR DAY 1 AND DAY 2.

Wow! Unreal for SE TX.

[RL3AO]

LIs of -8?

[Ed Mahmoud]

Based on obscene levels of instability and shear seen on both GFS and WRF soundings, Brenham, TX is my tornado pick city of tomorrow.

I'd have much preferred snow or sleet, (like the WRF was showing just 2 days ago) but at least the worst weather should be during daylight hours. I hope everyone is prepared.

[Ed Mahmoud]

LIs of -8?

I've seen LIs of almost -10º around DFW before. Usually later in the Spring, and usually with much more sane values of helicity. But still a recipe for pretty bad weather.

[btangy]

One negative for tornadoes I see is that the CAPE looks small near surface, with most of it between 700 mb and 250 mb (3 km to about 10.6 km), but the helicity is so high, I suspect it will more than compensate.

Agreed. The greatest instability is slightly elevated, which wouldn't be good for tornadoes. Likely to get some large hail though.

[Ed Mahmoud]

One negative for tornadoes I see is that the CAPE looks small near surface, with most of it between 700 mb and 250 mb (3 km to about 10.6 km), but the helicity is so high, I suspect it will more than compensate.

Agreed. The greatest instability is slightly elevated, which wouldn't be good for tornadoes. Likely to get some large hail though.

I hope so, but that is some freakish vorticity.

[HarlequinBoy]

Hey guys... if you don't mind, when posting SPC maps, etc., please upload to Imageshack, Photobucket, or somewhere else before posting the map. I was looking in a previous severe weather thread for when SPC went to moderate from slight and most of the maps were current because they were SPC image links. I did find what I was looking for because HarlequinBoy uploaded his maps to Photobucket (thanks). Anyway, just a suggestion and it makes for better records within the threads as well.

You're welcome.

[Ed Mahmoud]

Hey guys... if you don't mind, when posting SPC maps, etc., please upload to Imageshack, Photobucket, or somewhere else before posting the map. I was looking in a previous severe weather thread for when SPC went to moderate from slight and most of the maps were current because they were SPC image links. I did find what I was looking for because HarlequinBoy uploaded his maps to Photobucket (thanks). Anyway, just a suggestion and it makes for better records within the threads as well.

You're welcome.

I just hope you don't pull a muscle patting yourself on the back like that

[HarlequinBoy]

Heh, I'm quite flexible.

I'm concerned about tomorrow. SE Texas has a high population, and even though I don't think tomorrow will be nearly as intense as Super Tuesday, I think it could be significant. I'm not too confident we'll see an upgrade to HIGH, but that would be insane to get two in February.

[CrazyC83]

One negative for tornadoes I see is that the CAPE looks small near surface, with most of it between 700 mb and 250 mb (3 km to about 10.6 km), but the helicity is so high, I suspect it will more than compensate.

Agreed. The greatest instability is slightly elevated, which wouldn't be good for tornadoes. Likely to get some large hail though.

I wouldn't be surprised to see quite a bit of softball-sized hail out of this, whether the tornadoes happen or not...

[CrazyC83]

My guesses for tomorrow:

Initialize at MDT, with 10-hatched tornado, 30 wind, 60-hatched hail.

[Ed Mahmoud]

Still looks ominous early afternoon near the ice cream factory (ie, Brenham)




Even spookier looking for DW Hooks, closest airport to my house (well, IAH is about the same distance) late afternoon.



The main line should be about here at that time, if I am eyeballing the 6 hour accumulated precip correctly.

[RL3AO]

Day 1: MDT/15H T/30H H/45 W

[Ed Mahmoud]

Day 1: MDT/15H T/30H H/45 W

Pretty involved discussion. The MODERATE RISK area has shrunk somewhat from the Day 2 outlooks earlier today.