SPC AC 230525
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1125 PM CST SAT NOV 22 2008
VALID 231200Z - 241200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
SHORT WAVE TROUGH OVER ERN ORE/ID AS OF 23/04Z WILL AMPLIFY THROUGH
THE PERIOD AS IT PHASES WITH INTENSIFYING UPPER LOW OVER CNTRL
CANADA. THESE PHASED SYSTEMS WILL CONTRIBUTE TO SUBSTANTIAL HEIGHT
FALLS FROM THE NRN/CNTRL PLAINS EWD INTO THE UPPER GREAT LAKES AND
MID MS VALLEY. IN THE LOW LEVELS...ASSOCIATED COLD FRONT NOW
EMERGING FROM THE ROCKIES WILL PUSH EWD/SEWD THROUGH THE PLAINS
TODAY...EVENTUALLY REACHING THE CNTRL/LOWER MS VALLEY OVERNIGHT.
...LOWER MS VALLEY INTO THE ARKLATEX...
23/00Z SOUNDINGS OVER S TX AND CURRENT SURFACE OBSERVATIONS INDICATE
THAT LOW-LEVEL MOISTURE IS GRADUALLY INCREASING ALONG THE TX COAST
WITH BOUNDARY LAYER DEWPOINTS IN THE 50S AND PW VALUES OVER ONE
INCH. LOW-LEVEL MASS RESPONSE TO AMPLIFYING UPPER TROUGH OVER THE
CNTRL PLAINS WILL RESULT IN THE DEVELOPMENT OF A 30-40 KT SWLY LLJ
TODAY FROM ERN TX INTO THE OZARK PLATEAU REGION. THIS WILL SERVE TO
ENHANCE THE NEWD FLUX OF AN INCREASINGLY MOIST AIR MASS IN ADVANCE
OF SURFACE COLD FRONT. INITIALLY...MOISTURE WILL REMAIN LIMITED
BENEATH QUITE POOR MIDLEVEL LAPSE RATES WITH ONLY SHALLOW LAYER OF
CONVECTIVE INSTABILITY DEVELOPING TODAY WITHIN PRE-FRONTAL WARM
SECTOR. AS SUCH...NO TSTM DEVELOPMENT IS EXPECTED THROUGH THE
DIURNAL HEATING CYCLE.
SWLY LLJ WILL BE MAINTAINED OVERNIGHT /EVEN INTENSIFY/ FROM THE
ARKLATEX INTO THE TN AND OH VALLEYS...SUPPORTING CONTINUED
MOISTENING IN THE LOW LEVELS. THIS PROCESS WILL OCCUR BENEATH
STEEPENING MIDLEVEL LAPSE RATES ATTENDANT TO AMPLIFYING UPPER TROUGH
WITH THESE DIFFERENTIAL ADVECTIONS RESULTING IN A GRADUALLY
DEEPENING BUOYANCY LAYER WHERE MUCAPE MAY APPROACH 500-600 J/KG.
THIS AIR MASS DESTABILIZATION IN CONCERT WITH INCREASINGLY STRONG
DEEP LAYER FORCING FOR ASCENT ARE EXPECTED TO FOSTER ELEVATED TSTM
DEVELOPMENT /BASED AROUND 850 MB/ LATER TONIGHT INTO MONDAY MORNING
FROM PORTIONS OF THE LOWER MS VALLEY SWWD INTO THE ARKLATEX. WHILE
NO SEVERE WEATHER IS EXPECTED...SOME OF THE STRONGER STORMS COULD
CONTAIN SMALL HAIL.
..MEAD/BOTHWELL.. 11/23/2008
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
|
