SWODY2
SPC AC 191728
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT SUN OCT 19 2008
VALID 201200Z - 211200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
UPPER LEVEL FLOW PATTERN IS EXPECTED TO BE PROGRESSIVELY ZONAL
THROUGH THE DAY 2 FORECAST PERIOD. THE NRN STREAM WILL BECOME MORE
AMPLIFIED AS A CANADIAN TROUGH DEVELOPS SEWD INTO THE GREAT LAKES
REGION AND A PACIFIC TROUGH SPREADS INLAND ACROSS THE PACIFIC NW TO
THE NRN ROCKIES. MEANWHILE...SHORT WAVE TROUGH CURRENTLY MOVING
ACROSS CA DURING DAY 1 WILL TRACK FROM THE GREAT BASIN TO THE
CENTRAL HIGH PLAINS/SRN ROCKIES ON MONDAY.
...CENTRAL/SRN ROCKIES AND HIGH PLAINS...
COLD FRONT ACCOMPANYING GREAT LAKES TROUGH WILL MOVE E/SEWD ACROSS
THE GREAT LAKES AND OH/MID MS RIVER VALLEYS ON MONDAY...WHILE THE
TRAILING PORTION MOVES SLOWLY SWD AND STALLS ACROSS SRN OK. FROM
OK...THIS FRONT WILL EXTEND WWD THROUGH EAST CENTRAL NM AND BACK
INTO THE HIGHER TERRAIN OF NRN NM/CENTRAL CO. TSTM ACTIVITY THROUGH
THE AFTERNOON SHOULD BE CONFINED TO THE HIGHER TERRAIN OF THE
ROCKIES. HOWEVER...POST-FRONTAL UPSLOPE FLOW REGIME ACROSS NERN NM
COMBINED WITH THE LEADING EXTENT OF HEIGHT FALLS/COOLER MID LEVEL
TEMPERATURES SPREADING EWD ATOP LATE DAY WARM SURFACE TEMPERATURES
COULD PROVE FAVORABLE FOR A FEW SURFACE-BASED STORMS. GENERALLY
WEAK LOW LEVEL WINDS WOULD LIMIT SHEAR STRENGTH...BUT STRONGER UPPER
LEVEL WINDS WILL SUPPORT SUFFICIENT CLOUD LAYER SHEAR WHEN COMBINED
WITH WEAK INSTABILITY FOR A FEW STRONGER STORMS PRODUCING ISOLATED
HAIL/WIND. CONVECTIVE THREAT WILL LIKELY PERSIST EWD MONDAY NIGHT
INTO THE SRN HIGH PLAINS OF NERN NM TO SWRN KS WHERE INCREASING LOW
LEVEL WAA AND STEEP MID LEVEL LAPSE RATES FAVOR POTENTIAL FOR
ELEVATED TSTMS. FORECAST SOUNDINGS INDICATE 40-50 KT OF CLOUD LAYER
SHEAR AND MUCAPE 500-800 J/KG ROOTED AROUND 700 MB SHOULD SUPPORT AT
LEAST MARGINALLY SEVERE HAIL.
...WRN WA/NWRN ORE...
COLD FRONT ACCOMPANYING THE PROGRESSIVE PACIFIC TROUGH SHOULD BE
NEAR THE WA/ORE COAST AT 12Z MONDAY...WITH THIS BOUNDARY MOVING
QUICKLY INLAND AND REACHING ERN WA TO W/SW ORE BY 21/00Z. STRONG
FORCING FOR ASCENT WITHIN LEFT EXIT REGION OF 150+ KT UPPER LEVEL
JET IS FORECAST TO BE OVER THIS REGION MONDAY AFTERNOON. THIS
COMBINED WITH COLD MID LEVEL TEMPERATURES ATTENDANT TO PACIFIC
TROUGH SUGGEST POST-FRONTAL CONVECTIVE SHOWERS MAY BECOME DEEP
ENOUGH FOR CHARGE SEPARATION PRODUCING LIGHTNING STRIKES ACROSS FAR
WRN WA/NWRN ORE INTO THE EARLY EVENING.
...NRN ROCKIES...
MODELS INDICATE HEIGHT FALLS/COOLING MID LEVEL TEMPERATURES WITH
APPROACH OF PROGRESSIVE PACIFIC TROUGH MAY ALLOW FOR CONVECTIVE
SHOWERS TO BECOME DEEP ENOUGH FOR CHARGE SEPARATION. HOWEVER...
EXPECTED COVERAGE DOES NOT WARRANT MAINTAINING GENERAL TSTM OUTLOOK
ACROSS THIS REGION.
..PETERS.. 10/19/2008
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