[LeArc] DAY 1 CONVECTIVE OUTLOOK

[Duane Whittingham]

STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK DAY 1 CONVECTIVE
OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS. VALID 211630Z - 221200Z 
THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 45 ESE
CYS 25 SSE CYS 15 SSE LAR 15 NW CPR 35 W WRL 45 ENE JAC 15 ENE IDA 35
W MQM 10 NW DLN 15 WSW HLN 30 SSW GTF 35 NW LWT 55 ENE LWT 30 WSW MLS
40 N 81V 45 W CDR 25 S BFF 45 ESE CYS. 

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 15 NE
MBS 25 E SBN 30 N DNV 40 NW ALN 10 NNE OJC 25 WNW EMP 35 SSE RSL 15
WSW RSL 10 NE EAR 50 ENE ANW 25 SSE 9V9 15 NNW MHE 20 NW SPW 30 SE
RST 45 NNE GRB 30 SE ANJ. 
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SSE ELP 25 E TCS 40
WSW ONM 10 WSW SOW 20 S FLG 15 SE GCN 25 WSW U17 40 W U28 25 SW EVW
20 WSW MLD 25 ESE BOI 70 W BOI 50 SW BKE 30 NW ALW 20 NNE GEG 55 W
FCA 30 ESE HVR 55 N GGW ...CONT... 30 W CLE 25 NE DAY 50 ESE IND 30
NE OWB 30 W BWG 30 ENE BNA 15 E TYS 40 N HSE ...CONT... 65 NE MFE 20
S ALI 25 WSW NIR 45 SW CLL 25 N LIT 40 ENE HRO 25 S JLN 45 ENE OKC 65
NE P07 25 SE P07.

 ...SYNOPSIS... 

UPPER LOW REMAINS OVER PAC NW WITH SWLY FLOW ACROSS ROCKIES INTO HIGH
PLAINS. MID LEVEL S/WV TROUGH AND WIND MAX MOVING EWD ACROSS UPPER MS
VALLEY INTO WRN GREAT LAKES TODAY. PRIMARY SURFACE LOW PERSISTS
VICINITY NEB WITH LOW PRESSURE TROUGH EXTENDING ENEWD INTO WRN GREAT
LAKES THIS AFTERNOON/NIGHT. LOW LEVEL SLY FLOW E OF LOW TRANSPORTING
VERY MOIST AND UNSTABLE AIRMASS N/NEWD INTO UPPER MS VALLEY AND WRN
GREAT LAKES. 

...UPPER MIDWEST...

 VERY MOIST LOW LEVEL AIRMASS WITH DEWPOINTS INTO THE MID 70S SURGING
NEWD INTO SRN WI/IL THIS AFTERNOON AHEAD OF S/WV TROUGH NOTED ON SATL
IMAGERY WRN MN BORDER. WITH 30-40 KT DEEP LAYER SHEAR AND A VEERING
HODOGRAPH...PROFILES BECOME FAVORABLE FOR SUPERCELL DEVELOPMENT BY
MID/LATE AFTERNOON SWRN WI INTO NERN IA. HELICITIES FORECASTED TO
INCREASE TO ABOVE 200 M2/S2 THIS AREA. CAP WEAKENS TO ALLOW SURFACE
BASED STORMS TO DEVELOP LATER THIS AFTERNOON. WITH RATHER WEAK LAPSE
RATES AND HIGH PWS NEAR 2 INCHES SEVERE POTENTIAL WILL BE SOMEWHAT
LIMITED. HOWEVER WITH MLCAPES CLIMBING TO LEVELS GREATER THAN 2500
J/KG AND THE FAVORABLE SHEAR PROFILES...SEVERE THUNDERSTORMS SHOULD
DEVELOP BY LATE THIS AFTERNOON. PRIMARY THREAT WILL BE WET DOWNBURSTS
AND MARGINALLY SEVERE HAIL. 
HOWEVER THE SHEAR AND CAPE PARAMETERS DO SUPPORT ISOLATED TORNADOES
IN ANY SUPERCELL THAT DEVELOPS. FURTHER W INTO PLAINS...AIRMASS ALSO
WILL BECOME STRONGLY UNSTABLE FROM ERN NEB INTO KS AS TEMPERATURES
CLIMB THRU THE 90S COUPLED WITH NEAR 70 DEWPOINTS. WHILE DEEP LAYER
SHEAR IS WEAKER THAN FURTHER E...A FEW SEVERE THUNDERSTORMS EXPECTED
TO DEVELOP ALONG AND E OF LOW LEVEL SURFACE BOUNDARY NOW MOVING EWD
INTO CENTRAL NEB SWWD INTO SWRN KS. 

...NORTHERN ROCKIES...

SWLY FLOW AROUND UPPER LOW WILL PROVIDE BOTH STEEP LAPSE RATES AND
MID LEVEL MOISTURE WHILE LOW LEVEL ELYS CONTINUE TO SPREAD LOW LEVEL
MOISTURE INTO ERN MT. ALREADY ISOLATED STRONG/SEVERE THUNDERSTORMS
ERN MT. WITH HEATING MLCAPES WILL CLIMB TO 1500 J/KG ERN MT AND
SOMEWHAT LESS INTO NWRN WY/SWRN MT. THE COOL STEEP LAPSE RATES AND
MODERATE SWLY FLOW WILL ALLOW STORMS TO DEVELOP OVER HIGHER TERRAIN
THIS AFTERNOON WITH POTENTIAL FOR A FEW SEVERE STORMS GIVEN THE
FAVORABLY LOW WET BULB ZERO LEVELS. ACTIVITY WILL THEN SLOWLY DEVELOP
NE/E INTO HIGH PLAINS WHERE LOW LEVEL MOISTURE/INSTABILITY GREATER.
PRIMARY SEVERE THREAT WILL BE LARGE HAIL. 
...GULF COAST STATES...

 PULSE SEVERE THREAT TODAY SHOULD BE MOSTLY CONFINED TO SRN PORTIONS
OF GULF STATES WHERE VERY MOIST AND UNSTABLE AIRMASS CONTINUES.
PRIMARY THREAT WILL BE WET MICROBURSTS ENDING AROUND SUNSET. 

..HALES.. 08/21/02 
 
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Duane Whittingham (N9SSN) - Producer
Tom and Darryl Radio Shows
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