Watching the Skies

A Tornado Watch has been issued for Collin, Dallas, Tarrant counties as well as several others across central, east, and north Texas as well as eastern Oklahoma. The SPC has bumped this watch area up to a 10% tornado risk which is certainly worth paying attention to. While most of the metroplex is under a Tornado Watch, the cold front has mostly passed through the metroplex already so the threat is quite low, if not gone. There is currently a Severe Thunderstorm Warning for eastern Dallas county, but that storm has weakened and moved out of the warned area so I would expect this to expire shortly. Areas directly to the east and south of the Metroplex however should absolutely keep an eye on this situation since the severe weather threat and tornado potential is moderate.

Temperatures behind the front are 20 degrees lower, dropping temps from 75 down to 55 immediately behind.

URGENT – IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 781
NWS STORM PREDICTION CENTER NORMAN OK
1155 AM CDT THU OCT 29 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

SOUTHEAST OKLAHOMA
NORTHEAST TEXAS

EFFECTIVE THIS THURSDAY MORNING AND EVENING FROM 1155 AM UNTIL
600 PM CDT.

TORNADOES…HAIL TO 1 INCH IN DIAMETER…THUNDERSTORM WIND GUSTS
TO 80 MPH…AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE
MILES EAST AND WEST OF A LINE FROM 15 MILES EAST NORTHEAST OF
MUSKOGEE OKLAHOMA TO 40 MILES EAST SOUTHEAST OF TEMPLE TEXAS.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU1).

REMEMBER…A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.

OTHER WATCH INFORMATION…CONTINUE…WW 780…

DISCUSSION…THUNDERSTORMS ARE EXPECTED TO CONTINUE TO INTENSIFY
ALONG SLOW EWD-MOVING COLD FRONT THIS AFTERNOON. RICH BOUNDARY LAYER
MOISTURE AND STRONG TO INTENSE LOW THROUGH MID-LEVEL WIND FIELDS
WILL SUPPORT INCREASINGLY ORGANIZED STORMS/CELLS. WHILE ACTIVITY MAY
EVENTUALLY CONSOLIDATE INTO A SQUALL LINE WITH DAMAGING
WINDS…INITIAL/DISCRETE STORMS WILL EXISTS WITHIN VERY SUPPORTIVE
ENVIRONMENT FOR PERSISTENT LOW-LEVEL ROTATION AND POSSIBLE
TORNADOES.

AVIATION…TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 21045.

-- Weather in Frisco, TX when posted --
Temp: 64.4 °F, Dew: n/a, Humidity: 93%
Wind: n/a at n/a
Sky: n/a

Now that the heaviest rains are beginning to exist the Metroplex as they move east, I will send a brief update on tonight’s severe weather impacts. Only a few reports of high winds around the area, none of them reporting any damage so far. Several large hail reports in Parker, Tarrant, Denton and Cooke counties. One report of lightning striking a home in Trenton, 30 miles NE of Frisco, though damage is unknown at this time. Flooding impacts however are notable… several high water rescues have been reported in Fort Worth due to flooding rains stranding motorists or entering houses. Extreme north Collin county shows an estimated 6.24 inches of rainfall in the last 5 hours! The city of Celina, just 12 miles north of Frisco is embedded in a swath of the heaviest rains, reporting flood waters entering houses as well. There are also some road closures due to high waters south, and west of McKinney.

Attached is rainfall estimates since 6:22pm Sunday 10/25. You can see the area 2.5 miles north of Weston, or extreme north Collin and south Grayson counties showing up to 6.24 inches of rain. This is a result of several thunderstorms training across this area. Frisco by comparison is estimated around 1.17 inches, and only 19 miles south of the heaviest rainfall.

Right on time, a Severe Thunderstorm Watch has been issued for the DFW Metroplex until 1:00am CDT. Scattered showers are developing around the area including several within a few miles of Frisco. Isolated supercells are still possible this evening, primary threats remain as wind and hail.

URGENT – IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 775
NWS STORM PREDICTION CENTER NORMAN OK
715 PM CDT SUN OCT 25 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

SOUTHERN OKLAHOMA
NORTH CENTRAL TEXAS

EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 715 PM UNTIL
100 AM CDT.

HAIL TO 2 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 85
STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES SOUTHEAST OF
STEPHENVILLE TEXAS TO 40 MILES NORTHEAST OF ARDMORE OKLAHOMA.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU5).

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.

DISCUSSION…SCATTERED THUNDERSTORMS ARE INCREASING ALONG AND AHEAD
OF AN APPROACHING COLD FRONT OVER SOUTHERN OK AND NORTH CENTRAL TX.
RATHER COOL TEMPERATURES ALOFT AND INCREASING LOW LEVEL MOISTURE
WILL PROMOTE STRONG UPDRAFTS…WHILE SUFFICIENT EFFECTIVE SHEAR IS
PRESENT FOR A FEW SUPERCELLS.  PRESENT INDICATIONS ARE THAT THE MAIN
THREAT WILL BE LARGE HAIL…AND ISOLATED DAMAGING WINDS.

AVIATION…A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 24030.

Previous forecasts are still on track and all of north Texas looks set to receive a healthy drenching from heavy showers and thunderstorms for Wednesday. Currently cloud cover will continue to increase throughout the night as southern winds continue to feed moisture northward, then rain showers will start around the Metroplex close to 10am. The rain showers will continue the entire day until evening, when thunderstorms will develop. Instability in the atmosphere is still forecast to be low so severe storm potential is quite low. The showers and thunderstorms will continue through early Thursday morning and taper off close to 3am.

Flooding remains a good potential since the area lake and river basins are still filling into their flood control ponds and the soil is still relatively saturated. The weather service has issued a Flash Flood Watch for the eastern two thirds of north Texas for this reason. Our area is set to receive about 2 to 3 inches of rain with the possibility of more in localized pockets.

So remember to bring your umbrellas on Wednesday… Thursday through Sunday still look clear and cool in the forecasts… Monday brings a very small possibility of more rain showers but at this time chances are only 10% and not noted in any forecast descriptions.

-- Weather in Frisco, TX when posted --
Temp: 68 °F, Dew: n/a, Humidity: 72%
Wind: n/a at n/a
Sky: n/a

Heavy rains and Severe Thunderstorms are probable during the afternoon and evening hours of Thursday. The entire region is still under a Flash Flood Watch with around 2.5 inches of rain forecast the next 36 hours. Additionally the SPC in Oklahoma has our area under a ‘Slight’ severe storm risk with the main risk being severe winds. The local weather service noted in their forecast discussions that this is an event to take seriously. Flooding potential with this storm is quite high.

COPIOUS MOISTURE FOR THE SYSTEM TO
WORK WITH. IN MY MEMORY…I HAVE NOT SEEN PWAT/S THIS
HIGH…ESPECIALLY IN FALL…WITHOUT SEEING THE OCCURRENCE OF
FLASH FLOODING. FEEL THAT THIS IS AN EVENT TO BE TAKEN SERIOUSLY.

At this time we are in a 30% severe wind, 15% severe hail, and 2% tornado risk. The most likely time for these storms appears to be just before or around midnight. Thunderstorms are possible during the afternoon hours today as well, but the bulk of the severe activity is set around midnight… this is subject to change however.

Again flash flooding is a very likely possibility over the next 36 hours… flooding may be as bad or worse than any event we have seen since moving out to Texas a year ago.

-- Weather in Frisco, TX when posted --
Temp: 75.2 °F, Dew: n/a, Humidity: 94%
Wind: n/a at n/a
Sky: n/a

The National Weather Service has issued a Flash Flood Watch for the DFW Metroplex including Frisco, from 1pm Thursday through 7pm Friday. The area’s waterways and soil is already very saturated, plus when you factor in the upcoming forecasts, conditions begin to scream Flash Flood. The weather service compared the forecast event to events that happened October 14-15 2007 and October 18-19 2002. Both events saw abnormally high amounts of rainfall resulting in flooding, high water rescues, stranded vehicles etc. The weather service is forecasting a possibility of 4 inches of rainfall accumulation over our area.

-- Weather in Frisco, TX when posted --
Temp: 60.8 °F, Dew: n/a, Humidity: 72%
Wind: n/a at n/a
Sky: n/a

The SPC in Oklahoma has issued a Severe Thunderstorm Watch for the entire DFW Metroplex including Frisco. This watch expires at 6:00pm today, the main threat will be large hail, with a small possibility of severe wind gusts. Tornados are very unlikely today.

URGENT – IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 757
NWS STORM PREDICTION CENTER NORMAN OK
1155 AM CDT TUE OCT 6 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

CENTRAL AND NORTH CENTRAL TEXAS

EFFECTIVE THIS TUESDAY MORNING AND EVENING FROM 1155 AM UNTIL 600
PM CDT.

HAIL TO 2 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 50
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES NORTH
NORTHWEST OF SAN ANGELO TEXAS TO 15 MILES SOUTH SOUTHEAST OF
PARIS TEXAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).

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 756…

DISCUSSION…ELEVATED TSTM DEVELOPMENT /INCLUDING A SUPERCELL OR
TWO/ WILL CONTINUE WITHIN FEED OF MODERATE MUCAPE BEHIND SHALLOW
SURFACE COLD FRONT SAGGING SSEWD INTO CENTRAL TX THIS AFTERNOON.
GIVEN EFFECTIVE SHEAR AROUND 40-50 KT AND MODEST LAPSE
RATES…POTENTIAL FOR ISOLATED LARGE HAIL AND PERHAPS A
STRONG/SEVERE WIND REPORT REMAINS WITH THE STRONGER CORES.

AVIATION…A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 25020.

The SPC in Oklahoma has gone ahead and issued a Severe Thunderstorm Watch for our area, expiring at 11pm local time. Today’s threats have changed and has become mainly a hail and wind threat, while the tornado threat is now reduced to near-zero. Severe storms have developed over south central Oklahoma dumping severe-sized hail (larger than 0.75″) along a pre-frontal trough. The cold front is expected to overtake this trough later todayand shift the storm threat from large hail to more of a high wind event. Not sure on exact timing, but previous estimates of 6 to 7pm for ETA around Frisco still seems to hold up. Ill send more updates as I can.

URGENT – IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 752
NWS STORM PREDICTION CENTER NORMAN OK
350 PM CDT THU OCT 1 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

SMALL PART OF SOUTHEAST OKLAHOMA
LARGE PART OF NORTH CENTRAL AND NORTHEAST TEXAS

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 350 PM UNTIL
1100 PM CDT.

HAIL TO 2 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 85
STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH
NORTHWEST OF PARIS TEXAS TO 20 MILES SOUTH OF TEMPLE TEXAS.  FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU2).

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 751…

DISCUSSION…COLD FRONT MOVING SEWD INTO NRN TX ENCOUNTERING AN AIR
MASS THAT HAS BECOME MDTLY UNSTABLE.  WITH MLCAPES AOA 2000 J/KG AND
DEEP LAYER SHEAR OF 30-40 KT…SEVERE THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG AND E OF COLD FRONT AS IT CONTINUES SEWD ACROSS THE
WATCH.

AVIATION…A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 27025.

A Severe Thunderstorm Watch has been issued for the entire DFW Metroplex including Frisco until 11pm. Looks like the timing on this storm system has been pushed forward a bit and I am thinking of an ETA around maybe 10pm approximately? Watch details below…

URGENT – IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 743
NWS STORM PREDICTION CENTER NORMAN OK
430 PM CDT MON SEP 21 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

NORTH CENTRAL TEXAS

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 430 PM UNTIL
1100 PM CDT.

HAIL TO 2 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 90
STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH OF
DALLAS TEXAS TO 30 MILES SOUTHWEST OF STEPHENVILLE TEXAS.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU3).

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 742…

DISCUSSION…THUNDERSTORMS ARE DEVELOPING ALONG THE DRYLINE FROM
JUST E OF SPS TO E OF ABI.  STRONG INSTABILITY AND EFFECTIVE BULK
SHEAR AROUND 30 KT WILL SUPPORT A FEW PERSISTENT MULTICELL
CLUSTERS…AS WELL AS STORMS WITH SOME SUPERCELL STRUCTURES.  LARGE
HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS.  LATER THIS
EVENING…STORM INTERACTIONS COULD LEAD TO UPSCALE GROWTH INTO MORE
OF A LINEAR MCS…WITH A CONTINUING THREAT FOR DAMAGING WINDS AND
LARGE HAIL.

AVIATION…A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 27025.

Looks like the SPC decided to go ahead and issue a Severe Thunderstorm Watch for our area. The primary risk will be strong to severe winds with the stronger cells as downdrafts are favorable today. Severe hail is also possible with several storms showing radar indicated 2 inch hail at this time (hail is marked by the diamond icons on radar). Again the approximate ETA on this I am pushing forward by 15 minutes, so I am thinking 5:30 to 5:45pm now.

URGENT – IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 664
NWS STORM PREDICTION CENTER NORMAN OK
325 PM CDT WED AUG 5 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

EXTREME SOUTH CENTRAL OKLAHOMA
NORTH CENTRAL TEXAS

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 325 PM UNTIL
1000 PM CDT.

HAIL TO 2 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 65
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 60 MILES NORTH
NORTHWEST OF FORT WORTH TEXAS TO 80 MILES EAST OF DALLAS TEXAS.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU4).

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.

DISCUSSION…PREVIOUSLY ELEVATED THUNDERSTORM OVER CENTRAL/ERN OK
HAVE BECOME SURFACE-BASED AS THEY MOVE GENERALLY SWD INTO A HOT AND
MOIST SURFACE ENVIRONMENT…WHERE SURFACE TEMPERATURES ARE NEAR 100F
AND DEW POINTS ARE IN THE UPPER 60S-LOWER 70S.  THE STORMS APPEAR TO
HAVE DEVELOPED AN ORGANIZED COLD POOL WHICH IS EXPECTED TO SPREAD
SWD/SSWWD ACROSS THE RED RIVER INTO NRN TX DURING THE NEXT SEVERAL
HOURS.  THERE IS POTENTIAL FOR ADDITIONAL UPDRAFTS TO DEVELOP WWD
ALONG THE OUTFLOW BOUNDARY MOVING INTO EXTREME SOUTH CENTRAL
OKLAHOMA…WITH RESULTANT SWWD PROPAGATION TO THE CONVECTIVE SYSTEM.
DAMAGING WIND GUSTS AND OCCASIONAL HAIL ARE LIKELY WITH THE SYSTEM.

AVIATION…A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 34020.

-- Weather in Frisco, TX when posted --
Temp: 95 °F, Dew: n/a, Humidity: 47%
Wind: n/a at n/a
Sky: n/a