Moderate Risk has been posted for the area on Friday.
DAY 2 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
0124 AM CDT THU MAY 07 2009
VALID 081200Z - 091200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN HALF OF
OK...
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID SOUTH WWD THROUGH
THE SRN PLAINS...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE MID ATLANTIC
STATES...
CORRECTED FOR GENERAL TSTM LINE ACROSS GULF COAST STATES AND 5%
SEVERE PROBABILITY LINE IN NW TX
...SYNOPSIS...
MODELS REMAIN IN GOOD AGREEMENT WITH THE EVOLUTION OF THE MID/UPPER
FLOW PATTERN THROUGH DAY 2 /FRI/...AS A POSITIVELY TILTED TROUGH
OVER THE NRN HIGH PLAINS AT START OF PERIOD BECOMES ORIENTED
NEUTRALLY AS IT REACHES THE UPPER MS VALLEY. H5 HEIGHT FALLS WILL
SPREAD EWD INTO NORTH CENTRAL U.S./CENTRAL PLAINS AIDING IN
TIGHTENING THE MID LEVEL HEIGHT GRADIENT...AS A STRONG ELONGATED
RIDGE STRETCHES FROM MEXICO/TX TO FL. THIS WILL RESULT IN WNWLY
FLOW ALOFT BECOMING MORE ZONAL AND SHIFTING SWD TOWARD THE SRN
PLAINS AND OZARKS/MID SOUTH. MEANWHILE...A SHORTWAVE TROUGH LOCATED
OVER NWRN ONTARIO/UPPER GREAT LAKES REGION AT 12Z FRIDAY WILL TRACK
EWD ACROSS ONTARIO. A LEAD IMPULSE SHOULD MOVE OFF THE NRN AND MID
ATLANTIC COAST EARLY DAY 2...WHILE A WEAKER IMPULSE TRACKS EWD FROM
THE OH VALLEY REACHING THE MID ATLANTIC STATES FRIDAY AFTERNOON.
AT THE SURFACE ACROSS THE CENTRAL STATES...AN OUTFLOW BOUNDARY ALONG
SRN PERIPHERY OF LATE DAY 1 MCS EXPECTED BE ONGOING AT 12Z FRIDAY
ACROSS THE NRN HALF OF OK/SRN KS INTO OZARKS SHOULD EXTEND WWD FROM
CENTRAL AR THROUGH CENTRAL OK TO THE TX PANHANDLE.
ANOTHER...GENERALLY E-W BOUNDARY IS EXPECTED TO EXTEND FROM KS EWD
THROUGH LOWER MO TO OH VALLEYS. MEANWHILE...FARTHER N...A COLD
FRONT ATTENDANT TO THE UPPER TROUGH GREAT LAKES TROUGH AND AHEAD OF
NRN HIGH PLAINS TROUGH WILL SPREAD E/SEWD INTO UPPER MS VALLEY AND
CENTRAL PLAINS BY LATE FRIDAY AFTERNOON.
...SRN PLAINS...
AN MCS IS EXPECTED TO BE ONGOING AT 12Z FRIDAY OVER NRN OK/SRN KS
INTO THE OZARKS. SWLY LLJ WILL TRANSLATE EWD ACROSS AR/MID SOUTH
WITH WAA AND DESTABILIZATION DOWNSTREAM OF THIS COMPLEX LIKELY
MAINTAINING THIS SYSTEM AS IT PROGRESSES EWD FRIDAY MORNING/
AFTERNOON. INCREASING EFFECTIVE BULK SHEAR INTO THE MID SOUTH
SHOULD SUPPORT AN ORGANIZED SEVERE WEATHER THREAT WITH THIS
ACTIVITY.
MEANWHILE...STRONG SURFACE HEATING IS EXPECTED TO DEVELOP ACROSS
MUCH OF THE SRN HALF OF OK AND WWD THROUGH TX PANHANDLE TO SERN
CO/SWRN KS ALONG AND S OF MORNING MCS. STRENGTHENING SLY LLJ INTO
SRN OK DURING THE LATE AFTERNOON WILL INCREASE CONVERGENCE ALONG THE
E-W OUTFLOW BOUNDARY. THIS COMBINED WITH FORCING FOR ASCENT WITHIN
ENTRANCE REGION OF A MID LEVEL JET EXPECTED OVER THE OZARKS FRIDAY
AFTERNOON WILL SUPPORT TSTM DEVELOPMENT ACROSS MUCH OF CENTRAL/ERN
OK. VERY STEEP LAPSE RATES /EXCEEDING 8 C/KM/...SURFACE HEATING AND
RICH MOISTURE /SURFACE DEWPOINTS IN THE LOWER 70S/ WILL SUPPORT A
VERY UNSTABLE AIR MASS WITH MLCAPE EXCEEDING 3000 J/KG ACROSS
CENTRAL OK. INCREASING WLY MID LEVEL WINDS ACROSS THIS REGION BY
PEAK HEATING WILL STRENGTHEN DEEP LAYER SHEAR FOR SUPERCELLS...WITH
AN ATTENDANT THREAT FOR TORNADOES...VERY LARGE HAIL AND DAMAGING
WINDS. GIVEN THE LIKELIHOOD FOR TSTM DEVELOPMENT WITHIN THIS VERY
UNSTABLE/ STRONGLY SHEAR ENVIRONMENT...PARTS OF CENTRAL/ERN OK HAVE
BEEN UPGRADED TO A MODERATE RISK. ANOTHER MCS WITH ATTENDANT SEVERE
THREAT IS EXPECTED TO DEVELOP ACROSS MAINLY OK AND SPREAD EWD INTO
AR FRIDAY NIGHT AS LOW LEVEL WAA INCREASES ALONG THE NOSE OF A
STRONG VEERING LLJ.
FARTHER WNW...LOW LEVEL UPSLOPE FLOW INTO SERN CO SHOULD AID IN TSTM
DEVELOPMENT FRIDAY AFTERNOON. ORGANIZED SEVERE STORMS WILL BE
POSSIBLE AS ACTIVITY MOVES OFF THE HIGHER TERRAIN TOWARD SWRN KS/OK
PANHANDLE AND FAR NERN NM...WHERE THE AIR MASS WILL BE MODERATELY
UNSTABLE AND STRONGLY SHEARED.
Bookmarks