Severe Thunderstorm Warning 152, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
354PM CDT SAT MAY 11 2002

STORMS NOW DEVELOPING ALONG FRONT/DRYLINE OVER KS EXPECTED TO BUILD
SW-WARD AND DEVELOP INTO LINEAR MCS THIS EVENING AS FRONT MOVES SE.
ADDITIONAL STORMS POSSIBLE VICINITY DRYLINE INTO TX PANHANDLE WHICH
WOULD MOVE INTO W/NW OK THIS EVENING. HIGHEST POPS TONIGHT IN LIKELY
CAT ACROSS NC OK...TAPERING TO 20PCT ACROSS S. MESOETA FRONTAL
POSITION/MOVEMENT APPEAR REASONABLE...ALTHO CONVECIVE OUTFLOW MAY
ACCELERATE THE EFFECTIVE BOUNDARY. POPS INCREASED SUN AND EARLY SUN
NIGHT - ESPECIALLY E - AHEAD OF STRONG UPPER WAVE AND NEAR SLOW-
MOVING FRONT. SEVERE POTENTIAL AGAIN LATE SUN ACROSS SE PER
SWODY2...BUT THERE ALSO MAY BE POST FRONTAL RA/SHRA/DZ UNTIL UPPER
WAVE PASSES SUN EVENING. STRONG FRONT ACCOMPANIED BY CONSIDERABLE
COOLING AND POST-FRONTAL GUNGE MAKES HI TEMPS TRICKY ON SUN.
CLEARING/COOL SUN NIGHT BENEATH MODERATE COLD ADVECTION. NICE DAY
EXPECTED MON WITH MOSTLY CLEAR SKIES AND DECREASING N WINDS.

DAYS 3-7 /TUE-SAT/...DRY PERIOD EARLY-MID WEEK AS LONGWAVE RIDGE
MOVES TO CENTRAL STATES FOLLOWED BY INCREASING PRECIP CHANCES AS
RIDGE MOVES TO ECENTRAL/SE U.S. AND TROFFING REESTABLISHES OUT W.
MAIN QUESTION IS HOW FAST WILL THE PROGRESSION BE. PER LATEST
HPC DISCUSSION...THERE IS A LEAN TOWARD SLOWER AND LESS PROGRESSIVE
ECMWF/AVN ENSEMBLES OVER THE FASTER OPAVN. THIS IN TURN WOULD DELAY
THE INCREASING POPS AS WELL AS THE NEXT FRONT AND ANY ASSOCIATED
COOLING. TUE SHOULD BE A RECOVERY DAY TEMP-WISE AFTER A COOL
START...AS SURFACE RIDGE MOVES OFF TO E. MOISTURE RETURN THEREAFTER
MAY BE SLOWED A TAD INTO WED BY CONTINUED SURFACE RIDGING DOWN
TOWARD TX COAST AND W GULF. GUIDANCE TEMPS LOOK A BIT LOW ESPECIALLY
ON WED AS RIDGING DEVELOPS ALOFT...WHICH ALSO SHOULD REASSERT THE
CAP. THERE WILL STILL BE ENOUGH WESTERLY FLOW ALOFT TO PRESENT AN
OPPORTUNITY FOR DRYLINE MAGIC LATE WED...MAINLY TO OUR W. CHANCES
OF ANY STORMS GETTING INTO W PART OF CWA APPEAR TOO LOW TO MENTION
AT THIS TIME. POPS THEN INCREASE TO 20PCT THU-FRI AND TO 40PCT ALL
AREAS BY SAT AS FRONT ENTERS AREA AND FLOW ALOFT BACKS TO SW. OUR
FRONTAL TIMING IS SLOWER THAN LATEST OPAVN - MORE IN LINE WITH
HPC MANUAL PROGS. THERE APPEARS TO BE SOME POTENTIAL FOR A COUPLE
ACTIVE DRYLINE DAYS THU-FRI...AND PERHAPS SAT IF COLD FRONT IS AS
SLOW AS WE CURRENTLY THINK.

FCSTID = 24
OKC   65  72  49  71 /  30  40  40   0
HBR   63  74  47  73 /  20  30  30   0
SPS   66  81  50  73 /  20  30  40   0
GAG   51  60  44  71 /  40  30  10   0
PNC   61  68  48  70 /  60  50  50   0
DUA   69  83  55  72 /  20  60  60   0