Severe Thunderstorm Warning 427, NWS Tulsa, OK

FPUS3 KTUL 212107
AFDTUL

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
400 PM CDT MON SEP 21 1998

PROBLEM(S) OF THE DAY:
WILL THERE BE SEVERE CONVECTION?
POPS
TEMPERATURES

ZONAL FLOW HAS SETUP ACROSS LATITUDES NORTH OF ROUGHLY 35N. ACCORDING
TO COACH...HAVENT SEEN THIS REGIME SINCE MID-JUNE WHEN WE HAD
SIGNIFICANT SVR WX NEARBY.  PARAMETERS NOT TOGETHER FOR WIDESPREAD
SVR THIS GO AROUND...BUT COULD SEE SOME TONIGHT AND TUESDAY IN NRN
ZONES. PREFER ETA HANDLING OF LARGER SCALE FEATURES INCLUDING SFC
PRES AND H5 FLOW.  EVEN WITH FAIRLY WARM -6 TO -8C H5 TEMPS...L-M70
SFC DPS YIELDS 1000 J/KG SFC-BASED CAPE TONIGHT OVER CENTRAL OK.
THINK THAT ELEVATED INSTABILITY WILL ALSO BE PRESENT ALBEIT SLIGHTLY
LOWER WELL TO THE NORTH INTO ERN KS TONIGHT.  A NEG FACTOR FOR
WIDESPREAD SVR TONIGHT AND TUES IS FAIRLY WEAK H8 FLOW...SFC LOW
PRESSURE AND CONVECTION IN THE GULF MAY BE RESPONSIBLE FOR DISRUPTING
LOW LEVEL FLOW.  HAVE KEPT POP IN CHC CAT TONIGHT EXCEPT FOR
KS-ADJACENT ZONES.

ETA BUILDS H5 RIDGE BACK NORTH A LITTLE BUT DOES NOT STOP FRONT FROM
SLIPPING INTO OK AND AR.  THINK BRUNT OF COOLER AIR IN NE/KS WILL NOT
MAKE IT HERE BUT AM WORRIED LOOKING AT ICT FAN GUIDANCE TEMPS IN THE
UPPER 40S TONIGHT AND MID 60S TOMORROW.  HAVE GONE CLOSER TO FWC BUT
SLIGHTLY COOLER IN NRN ZONES.

EXTD LOOKS INTERESTING AS ZONAL FLOW AND BASE OF LARGE H5 TROUGH DIPS
WELL INTO OK THURS WITH GOOD INSTABILITY. COULD SEE A BETTER CHC OF
WIDESPREAD SVR THEN. SHOULD SEE COOLER WX ON FRI WITH ANOTHER FRONT
KNOCKING ON THE DOOR SAT. MAYBE WE WILL FINALLY SEE SOME EXTENDED
FALL WX AFTER THIS WRETCHEDLY HOT AND DUSTY SUMMER.

FCSTID = 26
TUL   68  82  64  85 /  50  50  30  10
FSM   68  89  66  88 /  20  40  10  10
MLC   72  89  66  91 /  20  30  10  10
BVO   64  78  62  84 /  70  50  40  20
FYV   65  82  61  82 /  50  50  10  10
IDB   69  94  68  92 /  10  10  10  10
BYV   65  82  61  82 /  50  50  10  10
MIO   64  78  61  83 /  60  50  20  10
MKO   69  87  66  86 /  30  50  20  10
F10   69  87  66  86 /  30  50  20  10
HHW   69  94  68  92 /  10  10  10  10

.TUL...
OK...NONE.
AR...NONE.

--------------------
EXPERIMENTAL OUTPUT:

EXPECTED MESOSCALE FEATURE: MODERATE OUTFLOW BOUNDARY
GENERAL WEATHER EXPECTED NEXT 24 HOURS: CONVECTIVE PRECIP
HAZARDOUS WEATHER EXPECTED NEXT 24 HOURS: SLIGHT CHANCE NONE
NGM CONFIDENCE:  6 ON A SCALE OF 0 TO 10
ETA CONFIDENCE:  7 ON A SCALE OF 0 TO 10
AVN CONFIDENCE:  7 ON A SCALE OF 0 TO 10
FCST CONFIDENCE: 7 ON A SCALE OF 0 TO 10
MOST USEFUL TOOL: MODEL GRIDS
BEST MODEL FIELD: H3 WINDS/DIVERGENCE.. H7 OMEGA.. BL WINDS.. H8
WINDS/DIVERGENCE