
Still probably will take the actual frontal passage, but at least a shot at beneficial rain.
Moderator: S2k Moderators
Extremeweatherguy wrote:We just had a brief, but intense, storm cell move through here. Lots of loud thunder, heavy rain, and perhaps even some very small hail..though I cannot confirm this.
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0330 AM CDT SUN MAY 11 2008
VALID 141200Z - 191200Z
...DISCUSSION...
EWD PROGRESSION OF UPPER TROUGH IS HANDLED SOMEWHAT DIFFERENTLY IN
THE MEDIUM RANGE GUIDANCE. GFS IS RELUCTANT TO SHUNT UPPER LOW
ACROSS THE SRN ROCKIES...THOUGH EMBEDDED SHORTWAVES WILL LIKELY
ADVECT DOWNSTREAM THROUGH THE PERIOD...WHILE ECMWF IS MORE
PROGRESSIVE WITH LONG WAVE TROUGH. RAMIFICATIONS OF DIFFERING MODEL
SOLUTIONS WILL BE THE EWD EXTENT OF SEVERE INTO THE CNTRL GULF
STATES...AND THE POSSIBILITY FOR LINGERING SEVERE ACROSS ERN TX IF
SLOWER SOLUTION IS NOTED. GIVEN THE MOISTURE RECOVERY ACROSS THE
SRN U.S...MID-HIGH LEVEL FLOW WILL BE MORE THAN SUPPORTIVE OF
ORGANIZED SEVERE AHEAD OF ADVANCING COLD FRONT.
..DARROW.. 05/11/2008
A storm early Sunday morning blew down trees and caused scattered power outages in Hardin and Jasper Counties.
The Hardin County Sheriff's Office tells KFDM News it received some reports of trees down and spotty power outages.
The Jasper County Sheriff's Office also received reports of downed trees and power lines, primarily near FM 105 and Gist Road in Evadale.
One viewer called KFDM News to report hail the size of tennis and softballs left holes in his roof.
Watch the Weekend Report with Nicole Murray at 5:30 p.m. and 10 p.m. Sunday, and Kerry Cooper's weather for more on the story.
http://www.kfdm.com/news/jasper_25984__ ... nties.html
Active weather period shaping up for the area including severe weather and heavy rainfall.
Synopsis:
Large upper trough digging into the SW US with downstream sub-tropical flow established over TX. Water vapor loop shows what appears to be a vort max approaching the Baja/W coast of Mexico and moving NE at around 80kts…with the upstream upper trough located over extreme western Nevada. Cold front at the surface and gravity wave aloft is noted in WV images over N TX where surface low pressure is forming in the E TX panhandle. At the surface warm moist Gulf air mass has surged back into the region with PWs rising back into the 1.5 in range and surface dewpoints of 70 or greater at most reporting stations. Additionally smoke/haze from fires burning in southern Mexico/central America is spreading up the TX coastline and will result in hazy conditions by afternoon…should not be as bad as Saturday. Near tropical air mass from the W Caribbean Sea will reach the region overnight with dewpoints rising into the mid to upper 70’s and PWS climbing above normal and close to 2.0 inches….we know what that means….excessive rainfall.
***The following is highly dependent on meso scale boundaries and processes and great forecast uncertainty remains tonight through Thursday as small scale features will drive large thunderstorms complexes across the state.***
Large upper trough will remain parked over the SW US while cool front stalls over NW TX and sub-tropical flow provides a wealth of ripples. Feel the first event will be this evening and tonight as storms fire along the C TX dry line and move ENE into at least the northern ½ of SE TX. Outflow boundaries will be produced and lay across the area on Wednesday.
Next disturbance should help fire off a new round of storms Wednesday along old outflow boundaries and once again along the C TX dry line during the afternoon. SPC has the entire area outlooked for Wednesday and is considering an upgrade to a moderate risk if local air mass remains juiced and is not worked over tonight by storms or as SPC put it “ a rogue MCS”.
Air mass will recover Wednesday evening awaiting next disturbance and main piece of energy Thursday morning. Majority of lift passes north of the area…however outflow boundaries may be generated and forced southward into the region sparking numerous storms. NAM and GFS show big QPF bullseyes over the ARKLATX back into E C TX where storms develop and train along a boundary. Very uncertain forecast by this period as convective developments today through late Wednesday will determine development on Thursday.
Heavy Rainfall Threat:
Given copious amounts of moisture that will be in place (PWS near the magic 2.0”) along with good low level Gulf inflow, slow moving surface boundaries, potential for cell training, and at times strong divergence aloft…the threat for heavy to excessive rainfall looks to be high. Main concern will be for a similar event to 5/5/08 where outflow boundaries becomes stalled and storms fire and train along the boundary with very high hourly rainfall rates. It is getting deeper into the warm season and rich tropical air masses can produce some big totals in short time periods. Basin wide amounts of 2-3 inches through Thursday look reasonable (1-2” across our SW zones…Matagorda Bay) although I would not be surprised to see a few 8-12 inch isolated totals over E TX.
Severe Threat:
Main threat appears to be large hail and wind damage along any MCS/bow echoes that form Wednesday or Thursday. Air mass will be fairly unstable by this afternoon and 850mb cap will slowly erode and possibly be broken by weak short waves in the noisy SW flow aloft. Feel the highest threat will come Wednesday and Thursday when large MCS may rake the area with more widespread wind damage…as noted above moderate risk may be needed on Wednesday.
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 316
NWS STORM PREDICTION CENTER NORMAN OK
955 PM CDT TUE MAY 13 2008
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
CENTRAL TEXAS
EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 955 PM
UNTIL 400 AM CDT.
HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60
STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES WEST
NORTHWEST OF COLLEGE STATION TEXAS TO 40 MILES SOUTH OF AUSTIN
TEXAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).
REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.
OTHER WATCH INFORMATION...CONTINUE...WW 312...WW 314...WW 315...
DISCUSSION...MCS WILL CONTINUE ADVANCING EWD ACROSS CENTRAL TX
OVERNIGHT...AND MAY EVOLVE INTO A MORE LINEAR SYSTEM AND INCREASE
ITS FORWARD SPEED. AIR MASS IS VERY UNSTABLE WITH STEEP LAPSE RATES
AND STRONG DEEP LAYER SHEAR...ENHANCING THE POTENTIAL FOR LARGE HAIL
WITH THE STRONGER CORES. WIND DAMAGE THREAT WOULD ALSO INCREASE IF
SYSTEM CONSOLIDATES ALONG LEADING OUTFLOW BOUNDARY AND SURGES ENEWD
INTO CENTRAL TX.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 26035.
Large MCS/bow echo over C/SC TX moving eastward this morning. Latest radar and satellite trends show weakening of this complex which is typical of such nocturnal systems. Meso vortex (bookend vortex) has been generated from convective explosion just W of Temple, TX with well defined front and rear inflow jets. Smaller scale bow E of KSAT which produced wind damage at the SAT Airport is weakening as it tracks just north of I-10. Outflow boundary is being produced along the southern edge of the line roughly from S of SAT toward LaGrange. Even with very good organization and well define meso vortex…expect this complex to weaken as it moves eastward away from main forcing of the upper trough over the SW US.
Main concern locally is how far east the thunderstorms get before they weaken and where any outflow/meso scale boundaries stall out to aid in potential afternoon development. Believe storms will weaken as they enter our western counties with outflow boundary stalling along a line from S of SAT toward the Hempstead area. With enough heating new storms may fire along this line this afternoon and move deeper into the region. Will also need to watch storms back W of SAT at this hour as they may organize into another MCS and move eastward.
Tonight – Thursday:
Main action/event as upper trough moves into TX and slow moving surface front moves across the area. Expect explosive thunderstorm development with slow moving excessive rainfall producers. Another MCS will form tonight along the slow moving front over C TX and will move slowly across SE TX Thursday. Meso scale features will once again drive the event so while the timing of the upper trough ejection looks good…outflow boundaries/bow echoes may send a rogue MCS crashing through the region early Thursday.
Severe Threat:
SPC has most of the area outlooked today and all the area outlooked on Thursday for severe storms. This is mainly a damaging wind and hail threat. Potential is there tonight into early Thursday for bow echo/LEWP to produce wind damage along the leading edge of the MCS.
Heavy Rainfall:
To show what this air mass is capable of…Shreveport, LA recorded 4.26” in 45 minutes yesterday evening and 6.34” in 1 hour and 15 minutes along with an astounding 3,223 lightening strikes in 1 hour. Very moist…tropical air mass…with dewpoints in the mid 70’s and PWS in the 1.8-2.0” range reside across all of E TX. Moist Gulf flow will be maintained into MCS complexes and mid level flow will become increasingly parallel to surface boundaries over time. Given very moist air mass and potential for warm rain production coupled with threat for cell training…flash flooding will be possible. A location could pick up several inches of rainfall in a very short period of times. Luckily grounds are fairly dry across the area…except for that region that saw the excessive rains on 5/5. Will not use HPC basin wide amounts as they are usually low and do not show the potential for excessive small scale rains as are common with these set-ups. Given the rainfall amounts to our N and W in the past 24-hours and the ongoing rains now over C TX…expect some rises to be generated on area rivers. Additional MCS activity with widespread 1-2” and isolated amounts of 3-4” will be possible. Locally higher totals of 6-8” are also possible where cell training/merging ocurrs.
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
942 AM CDT WED MAY 14 2008
THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A
* TORNADO WARNING FOR...
WASHINGTON COUNTY IN SOUTHEAST TEXAS...
* UNTIL 1030 AM CDT
* AT 936 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS TORNADO
WAS LOCATED NEAR BURTON..AND MOVING NORTHEAST AT 20 MPH.
* LOCATIONS IN THE TORNADO WARNING INCLUDE BUT ARE NOT LIMITED TO
QUARRY...INDEPENDENCE...BURTON...AND BRENHAM
THE SAFEST PLACE TO BE DURING A TORNADO IS IN THE INTERIOR HALLWAY OR
A ROOM SUCH AS A CLOSET ON THE LOWEST LEVEL OF A STURDY BUILDING. USE
BLANKETS OR PILLOWS TO COVER YOUR BODY AND ALWAYS STAY AWAY FROM
WINDOWS.
IF YOU ARE INSIDE A MOBILE HOME OR VEHICLE...EVACUATE THEM
IMMEDIATELY AND SEEK SHELTER INSIDE A STURDY BUILDING. AS A LAST
RESORT...SEEK SHELTER IN A CULVERT...DITCH OR LOW SPOT AND COVER YOUR
HEAD WITH YOUR HANDS.
A TORNADO WATCH IS IN EFFECT UNTIL 3 PM CDT FOR THE WARNED AREA.
PLEASE REPORT SEVERE WEATHER TO THE COUNTY SHERIFF...LOCAL POLICE...
OR DEPARTMENT OF PUBLIC SAFETY. THEY WILL RELAY YOUR REPORT TO THE
NATIONAL WEATHER SERVICE.
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1013 AM CDT WED MAY 14 2008
THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A
* TORNADO WARNING FOR...
NORTHERN MONTGOMERY COUNTY IN SOUTHEAST TEXAS...
WESTERN POLK COUNTY IN SOUTHEAST TEXAS...
NORTHERN SAN JACINTO COUNTY IN SOUTHEAST TEXAS...
SOUTHEASTERN WALKER COUNTY IN SOUTHEAST TEXAS...
* UNTIL 1100 AM CDT
* AT 1010 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
TORNADO WAS LOCATED 2 MILES NORTHWEST OF NEW WAVERLY..AND MOVING
NORTHEAST AT 23 MPH.
* LOCATIONS IN THE TORNADO WARNING INCLUDE BUT ARE NOT LIMITED TO
HUNTSVILLE STATE PARK...POINT BLANK AND COLDSPRING
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