SWODY1
SPC AC 171950
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0250 PM CDT MON OCT 17 2011
VALID 172000Z - 181200Z
...THERE IS A SLGT RISK OF SVR TSTMS THIS EVE ACROSS PARTS OF THE S
CNTRL PLAINS...
...20Z OUTLOOK UPDATE...S CNTRL PLAINS...
THE LACK OF STRONGER SOUTHERLY LOW-LEVEL FLOW AND SHEAR WITHIN THE
DEVELOPING PRE-FRONTAL INSTABILITY AXIS APPEARS LIKELY TO REMAIN A
LIMITING FACTOR CONCERNING THE SEVERE POTENTIAL. HOWEVER...DEEPER
LAYER VERTICAL SHEAR IS BECOMING STRONG AND SUPPORTIVE OF MID-LEVEL
UPDRAFT ROTATION. AND MODELS ARE SUGGESTIVE THAT MOISTENING BENEATH
RATHER STEEP MID-LEVEL LAPSE RATES IS CONTRIBUTING TO SIZABLE CAPE
WITHIN THE FAVORABLE HAIL GROWTH LAYER. ALTHOUGH FORCING FOR UPWARD
VERTICAL MOTION ASSOCIATED WITH THE APPROACHING DIGGING SHORT WAVE
TROUGH MAY NOT INITIATE STORMS UNTIL THE 18/00-03Z TIME FRAME...A
SEVERAL HOUR WINDOW OF OPPORTUNITY APPEARS TO EXIST THIS EVENING FOR
THE DEVELOPMENT OF STRONG/SEVERE STORMS ACROSS PARTS OF NORTH
CENTRAL TEXAS AND EASTERN OKLAHOMA...WITH LARGE HAIL THE PRIMARY
THREAT.
..KERR.. 10/17/2011
.PREV DISCUSSION... /ISSUED 1107 AM CDT MON OCT 17 2011/
...SOUTHERN PLAINS...
MORNING WATER VAPOR IMAGERY SHOWS A WELL-DEFINED SHORTWAVE TROUGH
DIGGING ACROSS THE FOUR-CORNERS REGION. THIS FEATURE WILL SWEEP
INTO THE CENTRAL/SOUTHERN PLAINS THIS EVENING. AFTER 00Z...MODELS
AGREE ON RAPIDLY INTENSIFYING NORTHERLY LOW LEVEL WINDS BEHIND A
COLD FRONT THAT WILL SURGE SOUTHWARD ACROSS THE SOUTHERN HIGH
PLAINS. LOW LEVEL WINDS AHEAD OF THE FRONT WILL NOT RESPOND/
INCREASE SIGNIFICANTLY TONIGHT...BUT INCREASING CONVERGENCE ALONG
THE FRONT WILL LEAD TO A LINE OF SHOWERS AND THUNDERSTORMS FROM
CENTRAL MO INTO NORTH TX.
MOISTURE IS SPREADING SLOWLY NORTHWARD ACROSS TX...WITH 50S
DEWPOINTS NOW INTO SOUTHEAST OK. A COMBINATION OF STRONG DAYTIME
HEATING AND COOLING TEMPERATURES ALOFT WILL YIELD AFTERNOON MLCAPE
UP TO 1000 J/KG NEAR THE APPROACHING FRONT. HOWEVER...FORECAST
SOUNDINGS SUGGEST THAT AN EML WILL LIKELY CAP THE WARM SECTOR AND
PRECLUDE DEEP CONVECTION. THE STORMS THAT FORM ARE EXPECTED TO BE
ALONG/BEHIND THE FRONT WHERE LIFT WILL BE SUFFICIENTLY DEEP. STEEP
MID LEVEL LAPSE RATES...COOLING TEMPERATURES ALOFT...AND STRENGTH OF
FORCING SUGGEST A RISK OF HAIL NEAR SEVERE LIMITS WITH THESE STORMS.
ALSO...STRONG NORTHERLY LOW LEVEL WINDS WILL NEED ONLY SLIGHT
CONVECTIVE AUGMENTATION TO PRODUCE LOCALLY DAMAGING GUSTS. THE
THREAT SHOULD DIMINISH BY MIDNIGHT AS DIURNAL COOLING WEAKENS
INSTABILITY. A SMALL SLIGHT RISK WAS CONSIDERED NEAR THE RED RIVER
/SOUTH OK AND NORTH TX/ WHERE INSTABILITY AND WIND FIELDS WOULD BE
MAXIMIZED...BUT TOO MUCH UNCERTAINTY REMAINS AT THIS TIME.
...FL KEYS...
LOCAL RADAR LOOPS CONTINUE TO SHOW SEVERAL SMALL SUPERCELLULAR
STORMS OFF THE SOUTHWEST COAST OF THE FL PENINSULA INCLUDING NEAR
THE KEYS. THIS SCENARIO WILL LIKELY PERSIST THROUGH THE AFTERNOON
IN NORTHEAST QUADRANT OF WEAK TROPICAL LOW. LIGHTNING DATA SHOWS
VERY FEW STRIKES IN THIS ACTIVITY...SUGGESTING THAT UPDRAFTS ARE NOT
PARTICULARLY STRONG. NEVERTHELESS...AN ISOLATED WATERSPOUT OR
TORNADO CANNOT BE RULED OUT.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.
No comments:
Post a Comment