Moderator: S2k Moderators
I'm crossing everything I have available and recruiting on the streets too!!!PTrackerLA wrote:Looks like some much needed rain is possible through midday Saturday according to the GFS. Let's all cross our fingers!
http://imageshack.us/m/204/8911/gfsp60096m.gif
And Jagno, I will aim some right at your house if we get any!!
Unfortunately it is only 0.05" so far, but it is a start. I still have everything crossed!! Jeff sent out another email this afternoon-Will need to have some changes for this afternoon and evening…main changes is to up the rain chances to 40% around Matagorda Bay up to College Station. Some locations have already had more rainfall this morning than in the past 3 months!
Widespread light rainfall with now a few thunderstorms around Victoria is moving across the region as an upper level disturbance and increasing moisture combine. Feel the best chances will remain out west and southwest around Matagorda Bay.
At the same time a massive thunderstorm complex has formed over NC TX extending southward to NW of Austin and is moving eastward. Widespread excessive rainfall is occurring under this complex and has even required a few flash flood warnings. May see this complex in some form reach into our northwest counties by late afternoon/early evening. Downstream air mass over SE TX is fairly unstable and marginally capped however strong inflow off the Gulf coupled with potential SE moving outflow boundary could support additional development.
Air mass has really moistened and is capable of some fairly high rainfall totals. Will need to keep a close eye on any west/east boundaries that may develop overnight/Thursday perpendicular to the strong inflow off the Gulf as they could produce training excessive rainfall.
Feel rainfall coverage and amounts for Thursday will need to be increased given the large amount of activity ongoing to our west and southwest today. Appears the shot at widespread wetting rains may indeed occur.
Chance for severe weather this afternoon and evening across the entire region.
Good shot at much needed rainfall.
Disturbance yesterday produced a taste of what is about to unfold in the next 12 hours across the region with many places seeing more rainfall yesterday than in the past 2 months. Next upper air disturbance is currently crossing the Rio Grande and already numerous severe thunderstorms are ongoing west of San Antonio and north of Del Rio…our activity for late today.
Local meso high pressure cell is in place this morning from short wave passage yesterday and overnight. This high will weaken and shift eastward today allowing he air mass over SE TX and the coastal bend to become very unstable. At last mid level capping has weakened due to southerly track of the approaching shot wave making the atmosphere more favorable for surface based thunderstorms. ENE moving NE Mexico disturbance will cross the region during maximum heating this afternoon favoring severe thunderstorms. Forecasted high temperatures in the upper 80’s will yield tremendous low level instability on the order of 3000-4000 J/kg while mid levels cool allowing steep lapse rates (the rate of rise of surface based air parcels) the steeper the rate the faster the surface air will rise vertically. Good inflow from the Gulf of Mexico is noted which will pump mid 70 degree dewpoint air mass into the disturbance and keep moisture profiles favorable. It all points to a good shot at rainfall.
Severe:
Cannot deny the parameters are in place for severe weather mainly wind damage and hail. 4KM WRF model continues to show the current cluster of storms growing upscale into a forward propagating MCS/large scale bow echo as it plows ESE into the mean low level flow over the region. This meso model has been showing this for the past several runs and the setup is similar to the event yesterday afternoon over N TX which resulted in a large scale bow echo and widespread wind damage. Will hit the wind threat the hardest as that is tending toward where the models are showing with their forecasted convective evolution patterns. Expect the current activity to grow upscale into a linear MCS over the next 2-4 hours and then begin to bow forward between Corpus Christi and San Antonio. Damaging wind threat will greatly increase as the leading edge begins to bow out toward the east and meso low (comma head) forms on the northern end of the complex. Cold pool generation will race eastward with the complex acting as a mini cold front and helping to sustain/maximize lift. Line/bow should reach our western counties by early to mid afternoon and sweep across the entire region from mid afternoon to mid evening. Main threat will be damaging winds of 50-70mph. Dry and brittle trees limbs will likely suffer damage even from non severe winds.
Rainfall:
Best shot at rainfall the entire area has seen and the feeling is pretty high that everyone will see at least some rainfall. Best chances will be west of I-45 where Gulf of Mexico ridge is the weakest. Will go with widespread .5-1.0 inch west of I-45 with isolated amounts up to 2.0 inches. If a fast moving bow echo develops these totals may be a touch high as the forward speed of the activity will greatly limit the duration of the event. East of I-45 totals will likely average about .5 of an inch lower.
Note: Convection yesterday W of Waco, TX was able to produce 8-10 inches of rainfall (flash flooding). There is some possibility that the main punch of the complex/bow echo may leave behind a stalling outflow boundary along US 59 or near the coast this evening. Should this happen very close attention will have to be paid to potential cell training or cell redevelopment overnight as a low level jet tries to re-establish across the region ahead of the main cold front Friday morning. Slow moving convection on any trailing outflow boundaries will be prodigious rainfall producers and could produce rapid flash flooding even with the excessively dry grounds.
Extended:
Cold front will move across the region Friday morning, but main activity and moisture should be shunted eastward with the disturbance overnight. Much drier and cooler air mass will filter into the region making for a sunny and cool (for May) weekend and early next week. Highs near 80 and lows in the upper 50’s will be a treat for this time of year.
Drought:
Yesterday marked the 58th day without rainfall at Hobby Airport…the streak should end today.
SPC has issued a Severe Thunderstorm Watch for all of SE TX, the coastal bend, and central Texas until 300pm.
Discussion:
Air mass is becoming very unstable already with little heating and large severe thunderstorms have developed west of College Station and around Austin. Large bowing MCS is approaching from the west from west of Waco to ESE of Del Rio moving ESE at 40kts. Middle section of the MCS has begun to bow ESE into the mean low level flow and expect a damaging bow echo to develop within the next 2-3 hours south of San Antonio and race ESE to SE toward the coastal bend.
Additional cells are developing out ahead of this main line as mentioned above in this warm and unstable air mass over the region. Cells have shown very slow forward motions and are producing excessive rainfall. Main threat from these cells will be large hail and isolated flash flooding as very heavy rain falls on dry hard ground. In fact areas in the exceptional drought have already netted upwards of 2-3 inches of rainfall in the last few hours…almost ½ of what they have had since October. Portions of Polk County received up to 5.0 inches overnight.
Given ongoing meso scale trends, expect bow echo to affected the Matagorda Bay region by early to mid afternoon and then push offshore. North of the main bowing segment a line of storms or possibly a secondary bow echo may develop and impact the rest of SE TX in the 200-500pm time frame. Wind damage threat will be greatly increasing over the next 2-3 hours as bow echo takes shape and drives toward the coast. Widespread winds of 55-70mph will be possible along the leading edge of this line producing wind damage.
Severe Thunderstorm Watch boxes in effect until 300pm.
WW0289 Radar
jasons wrote:Somehow I only have .37" so far....
PTrackerLA wrote:So happy for you Texas folks that really need the rain more so than we do! Looks like we could get a good soaking too, Lake Charles NWS even somewhat concerned over flash flooding potential!
SPC CONTINUES TO OUTLINE THE AREA IN A SLIGHT RISK FOR SEVERE
THUNDERSTORMS...THE WESTERN HALF FOR TODAY AND TONIGHT AND THE
ENTIRE AREA ON FRIDAY. BASED ON PROGGED PARAMETERS...THE TORNADO
THREAT IS LOW...WITH HAIL/DAMAGING WINDS THE PRIMARY SEVERE
WEATHER THREATS. GIVEN THE HIGH PWAT...LOCALLY HEAVY RAINFALL WILL
ALSO BE A CONCERN WITH TSTMS . IN FACT...GIVEN THE PROGGED
SYNOPTIC SETUP AND QPF PROGS THAT CONTINUE TO GRADUALLY CREEP
UP...I AM BECOMING A LITTLE MORE CONCERNED ABOUT A WIDESPREAD
HEAVY RAINFALL EVENT. IN DIFFERENT CIRCUMSTANCES...A FFA WOULD BE
CONSIDERED...BUT NOT AT THIS TIME GIVEN THE AMBIENT DROUGHT AND
HIGH FFG VALUES.
my Cowboys my Rockets my Astros my Cowboys my Rockets my Astros southerngale wrote:angelwing, It was actually Tuesday night. My mom sent it to me yesterday morning. Very cool video!
http://news.yahoo.com/s/yblog_localdallas/20110511/ts_yblog_localdallas/amazing-video-shows-transformers-exploding-in-fort-worth
