SE TEXAS SEVERE OUTLOOK

[Suzi Q]

Although North Texas is in for a good hit, looks as though we are too. Hopefully (for me at least) this pans out and does so AFTER my stupid chem class.

THE BIG QUESTION MARK FOR WEDNESDAY (AND BEYOND) IS THE SEVERE WEATHER POTENTIAL. WIND PROFILE BECOMES VERY FAVORABLE FOR ROTATING CELLS WED AFTN/EVENING WITH STRONG LOW LEVEL DIRECTIONAL AND SPEED SHEAR AND FORECAST HELICITIES OF 400-600 M2/S2. WARM SECTOR AND 60+ DEWPOINTS SHOULD AT LEAST MAKE IT NORTHWARD INTO OUR SOUTHERN ZONES BUT ONGOING CLOUDS/RAIN WILL LIMIT HEATING WEDNESDAY. THREAT APPEARS
GREATEST TOWARD THE COAST...BUT WILL HAVE TO WATCH THIS CLOSELY.

Suzi the spinning southern twister


P.S. I can't seem to get snow, so I'll take this in a heartbeat!

[OtherHD]

I'm tired of this stormy weather. Where is the sun?

[Guest]

You are tired of everything HD - not every day can be bright and sunny - perhaps you need the always sunny message board instead of here at storm2k where we like all kinds of weather.....

[KatDaddy]

This is the worst time of year for me. I perfer the longer daylight and 90 Degree temps.

I will however take the heavy rains and severe weather whenever I can Summer or Winter

[OtherHD]

You are tired of everything HD - not every day can be bright and sunny - perhaps you need the always sunny message board instead of here at storm2k where we like all kinds of weather.....

We need sun now so that I'll be tired of it once hurricane season comes. I still want hurricanes, but for now I want sun.

[TexasStooge]

Well, North Texas could use a whole mess of rain after last year's deficit.

[Suzi Q]

Ok, would like ya'll to met my NEW best friend Mr. Rockstock. Mentioned my two favorite words, math and tornadoes in the same post. Welcome darlin. Am fascinated by your calculations. Will PM you on how you got so smart while I'm driving all over SE Texas like a wild boar!!!!!

Suzi the Southern twister

[PTrackerLA]

We sure have gotten into a wet cycle it seems to rain every couple of days. I'll take the severe storms but they aren't as good as in the summer when you can actually watch them develop (towering cumulus clouds). Let's keep hoping for sneaux though!

[southerngale]

You are tired of everything HD - not every day can be bright and sunny - perhaps you need the always sunny message board instead of here at storm2k where we like all kinds of weather.....

lol

Oh, and bring on the thunderstorms!! I'm not gonna get any snow again this week.

[Suzi Q]

Here it comes. Don't get much busier than this folks (except in cane season or late March and April) As Jeb would say: BRING IT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
325 AM CST WED FEB 4 2004

...HEAVY RAIN AND SEVERE WEATHER EVENT TAKING SHAPE FOR SOUTHEAST
TEXAS...

.DISCUSSION...
SATELLITE IMAGERY SHOWS DEEP UPPER TROF OVER THE FOUR CORNERS REGION WITH DIFLUENT UPPER FLOW DEVELOPING ACROSS TEXAS. SURFACE OBS INDICATE DEWPOINTS ALREADY INTO THE LOWER/MID 60S ACROSS THE LOWER VALLEY/WESTERN GULF...WITH EASTERLY WINDS OF 20-25 KNOTS. THESE SIGNS POINT TO IMPRESSIVE MOISTURE RETURN OVER THE AREA TODAY.

EXPECTING TWO MAIN ROUNDS OF PRECIP: THE FIRST WILL OCCUR TODAY ASSOCIATED WITH STRONG 850 MB WARM ADVECTION. LOW LEVEL JET WILL INCREASE TO 40-50 KNOTS WHICH WILL HELP TRANSPORT PWS AROUND 1.3 INCHES NORTHWARD INTO THE CWA. THE QUESTION IS: WHEN WILL THE RAIN BEGIN? EXPECT RAIN WILL BEGIN AS VIRGA AND WILL TAKE SEVERAL HOURS TO SATURATE THE COLUMN. HAVE POPS AT 40 PCT FOR -RA THIS MORNING BUT THEN UPPED TO 90 PCT THIS AFTERNOON. MINOR FLOODING PROBLEMS WILL BE POSSIBLE LATE TODAY...BUT THE RAINFALL TODAY SHOULD BE MOSTLY LIGHT.

AFTER A BRIEF BREAK...A HEAVIER ROUND OF PRECIP WILL AFFECT US
TONIGHT INTO THURSDAY MORNING. AS 110 KNOT JET MAX APPROACHES FROM THE WEST...SE TX GOES INTO A FAVORABLE DOUBLE JET COUPLET WITH VERY STRONG UPPER DIFLUENCE AND LIFT MAXIMIZED FROM 03Z TO 12Z THURSDAY. PWS REMAIN IN THE 1.3-1.4 INCH RANGE OVER THE AREA. BAROCLINIC ZONE WILL SET UP OVER THE CWA TO FOCUS VERY STRONG LOW LEVEL CONVERGENCE. HPC DAY 1 QPF FORECAST HAS WIDESPREAD 2-3 INCH AMOUNTS FOR THE SOUTHERN HALF OF THE AREA. THE FF DECISION TREE ARGUES FOR ISOLATED AMOUNTS UP TO 8 INCHES THROUGH THURSDAY MORNING. HAVE DECIDED TO ISSUE AN FFA FOR ALL OF SOUTHEAST TEXAS FOR THIS AFTERNOON AND TONIGHT. AGAIN...NOT ANTICIPATING ANY MAJOR PROBLEMS UNTIL TONIGHT BUT THIS GIVES EVERYONE A HEADS UP.

THE OTHER PRESSING CONCERN IS THE SEVERE WEATHER THREAT. THINK THE WARM SECTOR (60+ DEWPOINTS) WILL DESTABILIZE AT LEAST THE AREAS SOUTH OF I-10 BY LATE TODAY/TONIGHT. MODEL FORECAST SOUNDINGS SHOW IMPRESSIVE VERTICAL SHEAR DEVELOPING WITH HELICITIES INCREASING TO 400-500 M2/S2. THIS SHEAR PROFILE WILL FAVOR A THREAT FOR SUPERCELLS AND ISOLATED TORNADOES LATE TODAY AND TONIGHT. PACIFIC COLD FRONT CROSSES THE AREA THURSDAY MORNING...ENDING THE HEAVY RAIN THREAT. A STRONGER COLD SURGE MOVES ACROSS SE TX THURSDAY
NIGHT...AND KEPT CHANCE POPS GOING AS ISENTROPIC LIFT DEVELOPS ABOVE THE COLDER SURFACE AIR.

.PRELIMINARY TEMPS/POPS...
COLLEGE STATION (CLL) 58 49 63 38 50 / 90 80 40 30 20
HOUSTON (IAH) 63 56 66 43 55 / 90 100 60 30 20
GALVESTON (GLS) 61 57 65 52 57 / 90 100 60 30 20
&&

.HGX WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FOR ALL OF SE TX THIS AFTERNOON/TONIGHT.
SCA 00-60 NM WATERS.
SCEC GALVESTON/MATAGORDA BAYS.
&&

Now if you'll excuse me I must go prepare the ark!

Suzi the Dancing southern twister

[Suzi Q]

A little note regarding my last post. I would NEVER wish any harm to those here or anywhere else during a severe weather outbreak. HOWEVER, since this is the area I hope to specialize in upon graduating, I DO get excited about these events as they provide me practical experience and knowledge that the classroom may not provide. Just don't want anyone to be offended thinking that I'm some kind of maniac. Ok, ok, so I AM a maniac but you get my drift.


Back to my twister dance.

[southerngale]

lol, if you're a maniac, I am too!! BRING IT ON!!

[Guest]

Okay I'm joining the manic club too.....Just wish I could get some good pictures from my front porch - but at least I will get a lightning show and get to watch it tonight.

Everyone stay safe and post your reports right here.

[vbhoutex]

More Math for ya. Southeastern Texas Math Forecast I prepared for Wednesday Evening after 4pm.


Dewpoint Forecast shows a dewpoint at 60= 50%
Surface Temperature will be at 63 degrees= 20%
Low Level Jet inflow at 850mb will be at 35-40 knots= 50%
Surface Moisture Carrying Wind= 100%
700MB Dry Air Carrying wind= 100%
Upper Level Jet Stream will be blowing at 70 knots= 25%
500MB vort values= 20%

Probability of Severe Thunderstorms is 56%
So with that 56% it corresponds with my charts on........

Moderate/High Severe Thunderstorm Risk
On a weather map, it would be SEVERE red shading.
Thunderstorm probability is 70%

CAPE=25%

HELICITY=500+ VIOLENT TORNADOES POSSBILE!
Hail values.

75%
100%
25%
0%
75%

added together is 275 or...

3/4 inch hail size expected or SEVERE THRESHOLD.

FORECAST.
Numerous Showers and Thunderstorms will develop during the afternoon hours. These storms will be in a very high helicity environment so it could support intense supercells, and tornadoes. Hail Paremeters show a 3/4 inch or SEVERE THRESHHOLD as well. 6 hrs later near midnight, the action should slow down some. The helicty levels will drop dramatically to near 200 throughout the evening to midnight. Also CAPE values will be near 500, and maybe a bit higher, so some good amounts there.

SEVERE WATCHES I WOULD ISSUE IF I WAS IN THE FORECAST OFFICE.
VALID WEDNESDAY AFTERNOON TO MIDNIGHT 20Z to 6Z

SEVERE THUNDERSTORM WATCH FROM 2pmCDT TILL 12amCSY.

TORNADO WATCH FROM 3pmCDT to 8pmCST.

Let's see if it happens like the Math predicts.

Kevin Martin

Thanks for the great discussion and explanation Kevin!!!! And you are, as our friends across the ond would say "spot on" because they have issued a forecast eerily similar to yours except they issued a FFWatch with rain amounts up to 8" due to training. Do you perchance have an inside source? Or are you that damn good?

Just picked up the official-here it is:

FLOOD WATCH IN EFFECT FOR ALL OF SE TX THIS AFTERNOON
AND TONIGHT.

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A FLOOD WATCH
FOR ALL OF SE TX FOR THIS AFTERNOON & TONIGHT.

A STRONG UPPER LEVEL STORM SYSTEM WILL APPROACH SE TX FROM
THE WEST TODAY TRANSPORTING DEEP GULF MOISTURE NORTHWARD INTO THE
AREA. RAIN & THUNDERSTORMS WILL DEVELOP BY LATE MORNING & CONTINUE
THROUGH THE AFTERNOON HRS. THE RAINFALL TODAY IS EXPECTED TO REMAIN
MOSTLY LIGHT.BUT SOME ISOLATED 1 TO 2 INCH AMOUNTS WILL BE POSSIBLE
THIS AFTERNOON.

A HEAVIER ROUND OF SHOWERS & THUNDERSTORMS IS EXPECTED TONIGHT WITH
AS THE STORM SYSTEM NEARS & DEEP MOISTURE INTERACTS WITH A
STATIONARY FRONT OVER THE AREA. THE RAINFALL MAY BECOME HEAVY AT
TIMES. SOME TRAINING OF THUNDERSTORMS IS EXPECTED WHERE HEAVY RAINFALL
OCCURS REPEATEDLY IN THE SAME AREA.

WIDESPREAD RAINFALL AMOUNTS OF 2 TO 3 INCHES ARE EXPECTED BY EARLY
THURSDAY.WITH ISOLATED TOTALS OF 6 TO 8 INCHES POSSIBLE.

MOST OF SE TX HAS EXPERIENCED HEAVY RAINFALL IN THE LAST
WEEK OR SO & THE GROUND IS SATURATED. ADDITIONAL HEAVY RAINFALL
COULD LEAD TO SIGNIFICANT FLOODING PROBLEMS.

A FLOOD WATCH MEANS RAPIDLY RISING WATER OR FLOODING IS POSSIBLE
WITHIN THE WATCH AREA. IF YOU ARE IN THE WATCH AREA.CHECK
PREPAREDNESS REQUIREMENTS.KEEP INFORMED.& BE READY FOR QUICK
ACTION IF FLOODING IS OBSERVED OR IF A WARNING IS ISSUED.

STAY TUNED TO NOAA WEATHER RADIO FOR LATER STATEMENTS CONCERNING THIS
FLOOD THREAT.

[Rockstock]

Hey, didn't I do the Math for ya right Southeast, Texas? Showed severe event was coming before they actually put it on the net.lol...So let's see if my math paremeters ride the storm situation perfect. Hail parameters showed SEVERE HAIL THRESHOLD. Thank you, and we'll see. Also, looks like This might be a sort of an Outbreak Through Mississippi Northeastward...

Kevin Martin

[bfez1]

We are expecting torrential rains starting tonight. 3-6 in of rain expected. We are also under a flash flood watch thru Thursday night.

[Rockstock]

Thanks VT, well I dont have any other sources but the Math. The only source I
can say I have is the Weather Models for my values, but that's a must to predict the
weather accurate. Ok well This is what I do. I have developed charts with values
and percents on each of them. I have many charts for Severe Weather, and ill just
give a sneak peek of it because Im actually putting it together for SPC, or NWS or
someone that can help get this math in my name and used throughout the weather
forecasting departments. ok,well first I look at the models. I then look at my
charts and match the values from the models. here is just a 3 chart example so
everyone would understand what the math is all about.


DEWPOINT FORECAST TABLE.

Greater than 75= 100%
65-74= 75%
55-64= 50%
45-55= 25%
45 and Lower= 0%
_________________________________________________________________
SURFACE TEMPERATURE FORECAST TABLE.

100+ Incredibly buoyant (if dewpoint greater than 55)= 100%
90-99+ Extremely buoyant (if dewpoint greater than 55)= 80%
80-89+ Very buoyant (if dewpoint greater than 55)= 60%
70-79 Fairly unstable (if dewpoint greater than 55)= 40%
60-69 Marginal (if dewpoint greater than 55)= 20%
--------------------------------------------------------------------
250MB UPPER LEVEL JET STREAM SPEED TABLE.250MB UPPER LEVEL JET S250MB UPPER LEVEL JET STREAM SPEED TABLE.250MB UPPER LEVEL JET STREAM SPEED TABLE.

Greater than 200 knots Incredible divergence= 100%
150 to 200 knots Large divergence= 75%
100 to 149 knots Good divergence= 50%
70 to 99 knots Marginal divergence= 25%
Less than 70 knots Small divergence= 0%
-----------------------------------------------
Ok those are 3 for ya. Ok let's do the Math. say all the values were the highest.

dewpoint was over 75
temperature was over 100
Jet Stream was over 200.

now look at the chart. what are the values?
100%
100%
100%
how many charts are there now?

3 is right.

so take the total percentage and divide by the number charts used

300 divided by 3= 100

so 100% severe potential based on that.

ok let's use more realistic values.
dewpoint 62
temperature 70
jet stream 120

ok what are the values for those?

50%
40%
50%
now add those together. you get.........

140.. now divded that by the number of charts used.

140 divided by 300 is.......

0.466666666666666666666667
0.46% of severe weather you say???
NO, move the decimal over to the right 2 times.

46.6 round to 47%

So 47% Severe Weather Potential. On my conclusion charts that would be.
Slight Risk of Severe Thunderstorms.
Orange on the Weather Channel Map.
45% chance of Thunderstorms.

Forecast would follow by looking at the helicty, CAPE, etc, and of course all the
charts i've used to do this. this was only 3 charts. I have so much more to make
the most sccurate forecast.

But based on this, I could say There is a 45% chance of Thunderstorms today.
Those Thunderstorms will be Strong, and a few could turn Severe with a 47% chance.

But I make better forecasts because I have all the charts, and values to work with.


Hope this helps. Wish me luck on my submission to NWS, SPC about this.

Kevin Martin

[Rockstock]

THIS WILL BE MY FINAL FORECAST FOR THE HOUSTON,TX AREA
NEW MODELS SUGGEST HIGHER SEVERE PROBABILITIES

FORECAST TIME IS 6pmCST Today till 12amCST. A 6 hr period.

Dewpoint Forecast shows a dewpoint at 60= 50%
Surface Temperature will be at 60 degrees= 20%
Low Level Jet inflow at 850mb will be at 40 knots= 50%
Surface Moisture Carrying Wind= 100%
700MB Dry Air Carrying wind= 100%
Upper Level Jet Stream will be blowing at 73 knots= 25%
500MB vort values= 20%

Probability of Severe Thunderstorms is 59%
So with that 59% it corresponds with my charts on........

High Severe Thunderstorm Risk
GREEN ALERT
YELLOW ALERT
ORANGE ALERT
RED ALERT
PINK ALERT

On a weather map, it would be SEVERE red shading.
WEAK THUNDERSTORMS
STRONG THUNDERSTORMS
SEVERE THUNDERSTORMS

Thunderstorm probability is 75%
no Thunderstorms expected.
Slight Chance
Chance
Possible
Likely
Run For the Hills


CAPE=50%

HELICITY=300-350 STRONG TORNADOES POSSBILE!
HIGHEST VALUES F2-F3

Hail values.

50%
100%
100%
0%
75%

added together is 325 or...

Greater Than 3/4 inch hail size expected or OVER SEVERE THRESHOLD

Forecast Discussion.
Models are more impressive than yesterday's runs. Dewpoints stayed the same, but the most interest was the CAPE values. CAPE values are expected to be nearing 1500-2000 j/kg during the period, making for a moderatly unstable atmosphere over the area. Helicity indexes differ from 400-450 at 6pm, and dropping to 200-250 nearing midnight, on the end of the 6 hr period. Tornadic Chances will be all through the period, however the strongest possible Tornado would happen from 6pm-8pmCST. Strongest Possible Tornado could be F3-F4 during the first 2 hours of the period. dropping to F1-F2 overnight towards the end. Hail parameters show an impressive 325 value. That is impressive according to my Math. Greater than 3/4 inch hail size expected with these storms. Expect strong winds with any of these Thunderstorms, as LL winds reach 40knots.

My Severe Watches.

Severe Thunderstorm Watch from 4pmCST to 1amCST
9 hour watch.

Tornado Watch from 5pmCST to 1amCST with the highest probability of a strong tornado from the beginning of the period.

Kevin Martin

[Rockstock]

Thunderstorms already popping up Northwest Of houston. These storm will move NE. Additional Storms that will be the Severe Threat tonight will start to form South of those in the next few hours.

Kevin Martin

[Rockstock]

More lightning showing, up and new developed Thunderstorm is off the coast to the SSW of the Houston area. since everything will be moving from the SW, this storm could be the start of the Severe Event later today. I expect the Thunderstorm Activity to just burst. Storms would already be developing in Houston right now, however the moisture is just beginning, and CAPE is still not present, and coming onshore from the SW. All the ingrediants for Severe Weather are slowly coming together.

Satellite Photos show high cloud cover over the entire houston area, however won't damper Thunderstorm Development.

Kevin Martin