SEVERE WEATHER FORECASTER
SEVERE WEATHER FORECASTER
*** SEVERE WEATHER WITH SOME TORNADOES TODAY ( FRIDAY) ACROSS LOWER OKLAHOMA***
*** EXTREMELY DANGEROUS WEATHER EXPECTED ON SATURDAY IN CENTRAL US****
*** LIKELY HOOD OF LONG TRACK DANGEROUS TORNADOES****
*** MOST SEVERE WEATHER WILL TAKE PLACE AT LATE EVENING INTO NIGHT HOURS***
***NIGHT-TIME TORNADOES ARE VERY LIKELY FOR CENTRAL USA***
The Large Positively tilted trough presently over California is all set to produce A HISTORIC TORNADO OUTBREAK ON SATURDAY IN CENTRAL USA. As was expected, Storm Prediction Center has UPGRADED the Moderate Risk to a High Risk for Saturday
THE HIGH RISK AREA IS FROM SALINA,KS TO OKLAHOMA CITY,OK .
Update as of 1830z GMT
Tornado Watch issued for SW OK across NW Texas-
URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 160 NWS STORM PREDICTION CENTER NORMAN OK 130 PM CDT FRI APR 13 2012 THE NWS STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS OF OKLAHOMA A SMALL PART OF NORTHWEST TEXAS EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 130 PM UNTIL 900 PM CDT. TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES WEST OF WICHITA FALLS TEXAS TO 20 MILES NORTH NORTHWEST OF PONCA CITY OKLAHOMA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0). 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. DISCUSSION...STORMS ARE BEGINNING TO DEVELOP OVER SWRN OK AS THE CAP HAS WEAKENED WITHIN A STRONGLY UNSTABLE ENVIRONMENT WITH MLCAPE OF 2000-2500 J/KG. ALTHOUGH DYNAMIC FORCING FOR LARGE SCALE ASCENT IS SUBTLE...NUMERICAL GUIDANCE INDICATES THAT STORMS WILL CONTINUE TO DEVELOP TOWARD NRN OK THIS AFTERNOON...WITH CONVECTIVE POTENTIAL ALSO INCREASING ALONG THE NWRN EDGE OF MOISTURE AS IT RETREATS NWWD LATER THIS AFTERNOON AND EVENING. DEEP LAYER SHEAR OF 40 KT IN THE LOWEST 6 KM WILL FAVOR FORMATION OF SUPERCELL STRUCTURES...WITH AN INITIAL THREAT FOR LARGE HAIL AND STRONG WIND GUSTS. WITH TIME...LOW LEVEL WINDS/SHEAR WILL STRENGTHEN WITH A SUBSEQUENT INCREASE IN TORNADO POTENTIAL LATER THIS AFTERNOON AND EVENING. AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM MOTION VECTOR 23025.
Thunderstorms are expected to fire today in Oklahoma area East of the dryline. Convective inhibition or CIN shall prevent storms from firing till late afternoon period. With sufficient day time heat, the CAP will break and storms will fire in the presence of Moderately Destabilized atmosphere of CAPE values over 2000J/Kg across Oklahoma and SFC Dewpoint over 70F for convection. Supported by Steep Lapse rates from late afternoon into evening and the best lifted indices of -7 at Oklahoma, developing storms shall strengthen and become capable of producing large size hails into the afternoon hours. Lack of supporting wind shear for afternoon hours coupled with lesser intensified LLJ shall prevent tornadoes developing till early evening portion.
After the evening initiates, presence of improvised shears and LLJ for moisture shall elevate the potentials for tornadoes across SW Oklahoma,Central OK,SW Texas Oklahoma Border ( around Wichita Falls,). The Hodographs are indicating extremely good curvatures and in agreement with tornadoes especially close to SW OK..
*** SINCE MOST OF THE TORNADOES ARE EXPECTED IN NIGHT PERIOD WITH STORM INITIATING AROUND 19Z-20Z WITH SUPERCELLS PEOPLE MUST PAY ATTENTION TO THE WEATHER AS NIGHT TIME TORNADOES ARE VERY DANGEROUS ***
*** SOUTH WEST OK,CENTRAL OK AND NW TEXAS-OKLAHOMA BORDER I.E CLOSE TO WICHITA FALLS,TX SHALL PAY SPECIAL ATTENTION FOR TORNADOES AT NIGHT PERIOD ***
HIGH RISK: SATURDAY
*** LIFE THREATENING SITUATION EXPECTED***
*** TWIN HIGH RISK AREAS***
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1231 PM CDT FRI APR 13 2012
VALID 141200Z - 151200Z
...THERE IS A HIGH RISK OF SVR TSTMS OVER ERN NEB AND FAR WRN IA...
...THERE IS A HIGH RISK OF SVR TSTMS FROM S CNTRL KS INTO W CNTRL
...THERE IS A MDT RISK OF SVR TSTMS FROM WRN OK INTO NEB AND IA...
...THERE IS A SLGT RISK OF SVR TSTMS FROM NW TX NWD INTO SRN MN AND
As the positive tilted trough digs further, the severe weather threat will shift Eastwards and become widespread on Saturday.
The Surface analysis depicts intensifying surface low to settle over KS-NE border on Saturday. The Surface Low shall be a driving factor for the low level jets and the moisture incursion from the Gulf of Mexico.
Above- Valid 0000z,Sun SFC analysis shows the L at NW KS
As the upper air jet surges further, it shall drive a pocket of cool air from West Central US into the plains which eventually will collide with the warm moist air from the south creating instability over a wedge area for convection. Morning period appears to have a capped environment across the warm sector east of the dryline. With enough day time heat after some showers at places like Oklahoma, capping shall break into afternoon as per the GFS and expect storm initiation robustly across western to central OK in CAPE over 2000J/Kg and upto 2000 J/Kg across Eastern Nebraska as per the GFS..
Moisture shall be abundant across the warm sector all due to the LLJ which maintains the 40-50kt strength till around 00z,GMT (15th April) and exploding to over 60kt after 03z thus adding to more severe weather threat!
Initially,the wind shears shall be limited across OK-KS area and pretty favorable for areas such as NE-IA and hence the primary tornado threat shall apply for Eastern NE and Western IA.. With the increase period, shears will also improve and lack of convergence across OK-KS shall produce discrete supercells capable of producing tornadoes particularly stronger at night period... Threat of Large hails persists as well
The Hodographs are much impressive for the NE-IA area than OK-KS which may imply stronger tornado likelyhood there... However the SPC has issued a "RARE TWIN HIGH RISK AREA"
KANSAS-OKLAHOMA HIGH RISK COVERS CITIES FROM SALINA,KS TO OKC,OK AND NE-IA HIGH RISK COVERS MAJOR CITIES LIKE NORFOLK,OMAHA,LINCOLN ( NE)
THIS IS GOING TO BE A HISTORIC TORNADO OUTBREAK***
STAY TUNED FOR UPDATES!!
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1231 PM CDT FRI APR 13 2012 VALID 141200Z - 151200Z ...THERE IS A HIGH RISK OF SVR TSTMS OVER ERN NEB AND FAR WRN IA... ...THERE IS A HIGH RISK OF SVR TSTMS FROM S CNTRL KS INTO W CNTRL OK... ...THERE IS A MDT RISK OF SVR TSTMS FROM WRN OK INTO NEB AND IA... ...THERE IS A SLGT RISK OF SVR TSTMS FROM NW TX NWD INTO SRN MN AND WRN IL...