January Weather Discussion: Slight Chance Severe Storms

[tireman4]

Hey Srain,,, where is Mr Heat Miser (Wxman57)? Does he still think this is a more north than south item (Arklatex as opposed to a more southern route)?

[wxman666]

Given the big update from HGX...which I have a tendency to agree with...I'd like to take this opportunity to post this for a bit of reflection.

http://weatherblog.abc13.com/2011/01/he ... unday.html

[srainhoutx]

The NAM suggests the sharp cold front arriving in TX Monday evening.

[wxman57]

Here's a meteogram from 6Z GFS. I think we may see upper 20s for lows Wed/Thu before a big warm-up Fri/Sat. Cold daytime highs, maybe only in the 30s Wed/Thu with clouds but little moisture around. Chances of seeing any frozen precip here is not zero, but they're not high due to a lack of moisture after noon Sunday. Heading to the office now to record a video covering the event.

[srainhoutx]

Thanks for the update, wxman57. I know you're going to be a bit busy today.

[redneckweather]

Hopefully the trend even come a bit more south since snow chances are just a hair off to my north now. Wow! I'm between Conroe and Montgomery by the way.


Special Weather Statement
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
540 AM CST SAT JAN 8 2011

TXZ163-164-176-177-179-082300-
HOUSTON-TRINITY-MADISON-WALKER-POLK-
INCLUDING THE CITIES OF...CROCKETT...TRINITY...GROVETON...
MADISONVILLE...HUNTSVILLE...LIVINGSTON...CORRIGAN...ONALASKA
540 AM CST SAT JAN 8 2011

...WINTRY PRECIPITATION POSSIBLE ACROSS THE NORTHEAST COUNTIES
SUNDAY AND SUNDAY NIGHT...

A STRONG UPPER LEVEL STORM SYSTEM WILL COMBINE WITH INCREASING
MOISTURE TO RESULT IN RAIN AND ISOLATED THUNDERSTORMS OVER THE
AREA TONIGHT THROUGH SUNDAY. THE RAIN IS EXPECTED TO MIX WITH
SNOW AND SLEET BEGINNING SUNDAY MORNING MAINLY OVER HOUSTON...
MADISON...TRINITY...AND NORTHERN POLK COUNTIES. IF THE CHANGEOVER
TO WINTRY PRECIPITATION OCCURS IN THE MORNING...THE POTENTIAL
EXISTS FOR SNOW AND SLEET ACCUMULATIONS OF 1 TO 2 INCHES IN THIS
AREA ON SUNDAY. IN ADDITION...ICING OF BRIDGES AND OVERPASSES WILL
BE POSSIBLE. A WINTER STORM WATCH MAY EVENTUALLY BE NEEDED FOR
PORTIONS OF THE AREA.

TEMPERATURES ARE EXPECTED TO FALL BELOW FREEZING EITHER SUNDAY
AFTERNOON OR SUNDAY EVENING. ON SUNDAY EVENING...SOME ADDITIONAL
PATCHY VERY LIGHT FREEZING RAIN OR DRIZZLE OR SNOW FLURRIES WILL
IMPACT THE AREA. MINOR ICING OF BRIDGES AND OVERPASSES WILL BE
POSSIBLE.

[Katdaddy]

A very active weather night ahead so I will enjoy this beautiful weather. I am expecting a stormy night here in N Galveston County. As far as the snow/sleet potential I will leave that to the folks up N to monitor as I will be monitoring heavy rainfall and possible severe weather along the coast overnight and into tomorrow morning. Of interest is this mornings AFD mentioning next Wednesday:

ISENTROPIC LIFT WILL
BEGIN WEDNESDAY AND PERSIST INTO THURSDAY...WITH MID LEVEL CLOUD
DECK FORMING. ALTHOUGH SOUNDINGS WOULD SUPPORT SLEET AND POSSIBLY
SNOW THIS PERIOD...HAVE LEFT PRECIP OUT OF THE FORECAST AS LOW
LEVELS ARE VERY DRY.

[redneckweather]

And coops to the GFS with this wintry storm system. I believe it first showed the possibilities Sunday/Monday last week? I think it was showing it further south but none the less, it showed it.

[srainhoutx]

The 12Z GFS is sniffing out an area of wintry weather near Austin. Best dynamics suggested by that model will be NE TX and points E. We shall see.

[randybpt]

i have had a chance to study the long range, but i have heard that we will see a pretty good warm up late next week, how about the next week im on vacation. any chance to fire up the snow machine wxman??

[unome]

ImpactWeather has an updated video posted this am

http://www.youtube.com/user/impactweather

[srainhoutx]

The 12Z GFS does suggest a very slight chance of upper level moisture during the late Wednesday/early Thursday time frame as an Upper Level Disturbance swings by.

[srainhoutx]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0955 AM CST SAT JAN 08 2011

VALID 081630Z - 091200Z

...NO SVR TSTM AREAS FORECAST...

...SOUTH TX...
MORNING WATER VAPOR IMAGERY SHOWS AN UPPER LOW ALONG THE AZ/MEXICAN
BORDER. THIS FEATURE IS EXPECTED TO MOVE EASTWARD RATHER QUICKLY
DURING THIS FORECAST PERIOD...AFFECTING MUCH OF TX BY 09/12Z. AN
INCREASINGLY MOIST BOUNDARY LAYER AIR MASS IS IN PLACE ACROSS DEEP
SOUTH TX WITH DEWPOINTS IN THE UPPER 60S SOUTH OF A WARM FRONT
EXTENDING FROM SOUTH OF LRD-SOUTH OF CRP. STRENGTHENING SOUTHERLY
LOW LEVEL WINDS AHEAD OF THE APPROACHING UPPER SYSTEM WILL HELP TO
SHIFT THE WARM FRONT NORTHWARD INTO SOUTH-CENTRAL TX...AND ALLOW THE
MOIST/UNSTABLE AIR MASS TO MOVE SLIGHTLY NORTHWARD AS WELL. COOLING
MID LEVEL TEMPERATURES AFTER DARK WILL STEEPEN LAPSE RATES AND LEAD
TO SCATTERED THUNDERSTORMS OVERNIGHT.

MODEL FORECAST SOUNDINGS ACROSS SOUTH TX FOR LATE TONIGHT SUGGEST
FAVORABLE LOW-LEVEL AND DEEP-LAYER VERTICAL SHEAR FOR ORGANIZED
THUNDERSTORMS OR EVEN AN ISOLATED SUPERCELL. THE PRIMARY CONCERN
REGARDING SEVERE STORMS INVOLVES THE FORECAST OF SOME REMNANT
CAPPING THAT MAY LIMIT CONVECTIVE DEVELOPMENT TO ALONG OR NORTH OF
THE WARM FRONT. IF THIS OCCURS...MARGINALLY SEVERE HAIL WILL BE THE
MAIN THREAT. IF DISCRETE STORMS CAN FORM SOUTH OF THE WARM
FRONT...A GREATER SEVERE THREAT /WIND DAMAGE OR AN ISOLATED TORNADO/
WOULD BE REALIZED. THIS SCENARIO WILL BE MONITORED IN LATER
UPDATES.

..HART/SMITH.. 01/08/2011

[srainhoutx]

E-mail from Jeff just received...

Significant storm system heading for TX.

Major weather impacts starting tonight for all areas

Heavy rainfall and flooding possible near the coast, snow and sleet likely interior regions with accumulations.

Discussion:
Impressive upper level storm system over southern Arizona is making the treck toward TX this morning. A weak surface cold front has moved through all of SE TX and is stalling over the coastal bend and NW Gulf, but this has allowed a very dry air mass at the surface to move into the region from the NE providing low dewpoints and setting the stage for a winter mix over our N and NE counties. Surface low will rapidly form over S TX this afternoon and quickly deepen while moving NE up the TX coast ahead of the strong forcing from the approaching upper level storm. Tremendous moisture will overrun the returning warm front with clouds rapidly developing and lowering and light rain breaking out over Matagorda Bay by early evening. Rain will quickly spread across all of SC and SE TX by late tonight. Forecast soundings over our NE counties do show the threat for precipitation starting as sleet/snow late tonight from roughly Madisonville to Lufkin.

Surface low really deepens early Sunday while moving up the TX coast with pressures falling to 1005mb. Very strong ESE winds will develop SE of the low with high SCA/low end gale conditions likely over the upper TX coastal waters Sunday. Widespread thunderstorms and heavy rains will advance across the entire region by early Sunday morning as both surface low and warm front move into SE TX. Still hard to determine where the warm front will end up, but along and south of this boundary will favor an excessive rainfall/flooding threat.

Strong low pressure will move ENE into SC LA by Sunday evening ending the rainfall of most of the area. Strong cold air advection will drive temperatures into the 30's by Monday morning.

Given the vast impacts this system is going to produce, will break each one out below:

Rainfall:
Widespread rainfall amounts of 1-3" is likely with isolated totals upwards of 4 inches espcailly along and S of I-10. Moisture levels are forecast to reach at least 200% above normal for early January supporting an excessive rainfall threat. Hourly rainfall rates of 1-1.5 inches will be possible under the stornger storms. Still expect a period of training cells near the warm front and this is where the greatest flooding threat will be.

Wind:
Deepening low pressure will produce a period of strong winds across the region, especially near the coast. Winds will shift to the ESE and SE tonight and increase into the 20-30mph range with gust to 40mph along the coastal locations. Winds will then shift to the NW and WNW behind the low on Sunday on the order fo 15-25mph and gusty. A wind advisory may be required for the coastal counties this evening. A few severe thunderstorms south of the warm front may produce damaging winds of 50-60mph early Sunday.

Tides:
Developing strong onshore flow will result in water level rises along the upper TX coast tonight into Sunday morning. Tides are forecast to reach 2.0-3.0 feet above normal by early Sunday morning possibly resulting in minor overwash on the west side of Galveston Bay, the west end of Galveston Island, Bolivar Peninsula, and the coastal beaches of Brazoria and Matagorda Counties. At this time significant coastal flooding is not expected.

Sleet/Snow and Accumulations:
Latest development overnight has been the trending downward of temperatures and profiles over our northern counties on Sunday as the upper level storm moves overhead. Forecast soundings for Lufkin and across our northern counties of (Houston, Trinity, Polk, and Madison) support precipitation starting as sleet/snow tonight then changing to rain early Sunday and then back to possibly heavy wet snow/sleet by noon Sunday. Little to no accumulation is expected tonight, but back edge of rain shield on Sunday midday may produce a period of heavy wet snow with rapid accumulations over the above mentioned counties. Along and north of a line from Madisonville to Groveton accumulations of 1-2 inches will be possible. Accumulations of 3-6 inches are possible northeast of our area where Winter Storm Watches have been issued. Winter Storm Watches or Advisories may be required for the above mentioned counties by this evening.

Temperatures will fall below freezing by late Sunday afternoon from Madisonville to Groveton resulting in freezing of water on bridges and overpasses. Freezing line will progress southward to College Station to Huntsville to Livingston by midnight with the threat for light freezing drizzle. Road surface still wet may freeze and ice over and travel north of Hunstville by late Sunday may become hazardous due to ice and snow accumulations over our northern counties into N and NE TX.

Current forecast hold temperatures above freezing across the rest of the area and do not expect any icing of bridges and overpasses.

Next Week:
Much focus on the near term with significant system approaching. Still looking cold next week with cloudy skies behind the arctic boundary Tuesday-Thursday. Models still trying to bring a weak short wave across Wednesday night/Thursday morning in the cold air and generating some QPF. Would be looking at P-type problems if moisture is able to reach the ground, but for now will go with just an increase in mid level clouds and await better model agreement. Will maintain only about a 5-8 degree range in lows/highs Tue-Thurs given expected clouds...so most of the time will be spent in the 30's.

[txflagwaver]

Just got that from Jeff...Geez 50-60 mph winds????
Does this look probable of is it one of those sound the alarm but not much comes of it deals?

[ticka1]

My hubby is working today doing load test for their customer's generators - he will be there late - can anyone tell me when the rains will start tonight or after midnight? He works with electricity and they need to know so they can have everything finished by the time the rain starts.

[wxman57]

My hubby is working today doing load test for their customer's generators - he will be there late - can anyone tell me when the rains will start tonight or after midnight? He works with electricity and they need to know so they can have everything finished by the time the rain starts.

Ticka, a meteogram will help to identify the rain times. Here's one (below). The first green precip bar on the graphic is along the 3AM Sunday timeline. That means the precip starts in the 3 hours prior to 3am, or after midnight according to the 12Z GFS. Heaviest precip, nearly 0.9" is indicated at 9am Sunday (falls between 6am and 9am). Last green bar, almost 1/2", is at 12PM, indicating it falls between 9am and noon Sunday. No precip at 3PM Sunday, indicating the precip ends by noon Sunday.

[ticka1]

Thank you wxman57 for your reply. Its greatly appreciated. I just texted the info to my hubby.

[srainhoutx]

Just got that from Jeff...Geez 50-60 mph winds????
Does this look probable of is it one of those sound the alarm but not much comes of it deals?

Difficult to say at this time, txflagwaver. Everything depends on how the dynamics play out. With that said it is prudent to cover the possibilities, both good and bad regarding what the sensible weather could be.

[wxman57]

Thank you wxman57 for your reply. Its greatly appreciated. I just texted the info to my hubby.

You're welcome. We could see a few light sprinkles in spots prior to midnight this evening, but it looks like the real rain starts after 3am.

Well, heading out on our bikes to Discovery Green now. They're having an ice sculpting event there today.
http://www.discoverygreen.com/ebevents/event/37924522/