SPC AC 140550
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1250 AM CDT TUE JUL 14 2009
VALID 151200Z - 161200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM CENTRAL/SRN MO EWD INTO
THE OH VALLEY...
....SYNOPSIS...
BROAD UPPER TROUGH FROM THE NRN PLAINS EWD INTO THE WRN GREAT LAKES
WILL GRADUALLY DEEPEN SEWD INTO THE UPPER MIDWEST. THIS WILL OCCUR
IN RESPONSE TO A LARGE HIGH PRESSURE ALOFT...CURRENTLY LOCATED OVER
THE SOUTH CENTRAL CONUS....SHIFTING WWD INTO THE SWRN STATES...AND
BUILDING NWD ACROSS THE INTERMOUNTAIN WEST. SURFACE LOW ASSOCIATED
WITH UPPER TROUGH SHOULD PROGRESS EWD ACROSS ONTARIO DURING THE
PERIOD. TRAILING COLD FRONT...BY LATE WED AFTERNOON...IS EXPECTED TO
EXTEND FROM THE WRN GREAT LAKES SWWD THROUGH CENTRAL MO AND THEN
WSWWD INTO NRN OK/TX PANHANDLE.
...LOWER GREAT LAKES/UPPER OH VALLEY...
THUNDERSTORMS MAY BE ONGOING EARLY IN THE PERIOD ACROSS PARTS OF THE
WRN GREAT LAKES INTO IL...WITHIN AREA OF LIFT ASSOCIATED WITH LOW
LEVEL JET/WARM ADVECTION. THIS CONVECTION IS LIKELY TO SHIFT EWD
ACROSS LOWER MI DURING THE MORNING...BUT EXTENSIVE CLOUD COVER AND
RELATIVELY COOL TEMPERATURES SHOULD RESULT IN WEAK INSTABILITY AND
LOW POTENTIAL FOR SEVERE STORMS WITH THIS STORM CLUSTER.
-
HOWEVER...AS TEMPERATURES WARM THE MOIST BOUNDARY LAYER AHEAD OF THE
COLD FRONT...THE AIR MASS FROM CENTRAL/SRN MO EWD INTO THE OH VALLEY
WILL BECOME STRONGLY UNSTABLE....WITH MLCAPES FROM 2000-3000 J/KG.
AS SCATTERED STORMS DEVELOP...STRENGTHENING MID LEVEL WINDS AT 40-50
KT WILL PROVIDE FAVORABLE DEEP LAYER SHEAR FOR SEVERE STORMS. THOUGH
THE SHEAR MAY BE STRONG ENOUGH TO SUPPORT A FEW SUPERCELLS...
UNIDIRECTIONAL WLY WINDS THROUGH MOST OF THE TROPOSPHERE INDICATES
GREATEST POTENTIAL FOR LINE SEGMENTS WITH WIND DAMAGE.
...SRN KS/NRN OK WWD INTO SERN CO/NERN NM...
VERY STRONG HEATING...TEMPERATURES AOA 100 DEGREES...AND FRONTAL
CONVERGENCE ARE EXPECTED TO PROVIDE ENOUGH LIFT FOR THUNDERSTORMS TO
DEVELOP DURING THE LATE AFTERNOON/OVERNIGHT HOURS FROM SRN KS/NRN OK
WWD INTO SERN CO/NERN NM. THOUGH WEAK INSTABILITY PRECLUDES A SLIGHT
RISK AREA ATTM...DEEPLY MIXED BOUNDARY LAYER IS LIKELY TO RESULT IN
STRONG AND POSSIBLY A FEW SEVERE WIND GUSTS.
...CENTRAL HIGH PLAINS...
STORMS ARE ALSO EXPECTED TO DEVELOP WED EVENING ACROSS PARTS OF THE
REGION DUE TO INCREASING SELY LOW LEVEL WINDS/WARM ADVECTION AS A
SEWD MOVING SHORTWAVE TROUGH APPROACHES THE REGION. THOUGH DEEP
LAYER SHEAR WILL BE SUFFICIENT FOR SEVERE STORMS...DUE TO STRONGLY
VEERING WINDS IN THE LOWER 5 KM...MODELS SHOW WARMING TEMPERATURES
AT 700 MB...WHICH MAY INHIBIT MORE MOIST/UNSTABLE BOUNDARY LAYER
PARCELS FROM BEING INGESTED INTO STORMS.
..IMY.. 07/14/2009
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
|
