Post by hardcoreweather on Jan 4, 2009 6:47:16 GMT -6
Day 3 and already a slight risk from the SPC
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0139 AM CST SUN JAN 04 2009
VALID 061200Z - 071200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER THE GULF COAST STATES...
...SYNOPSIS...
A POWERFUL LARGE-SCALE TROUGH WILL PROGRESS EWD FROM THE GREAT
PLAINS INTO THE MS VALLEY DURING THE DAY THREE PERIOD. AS THIS
OCCURS...100+ KT MIDLEVEL JET STREAK WILL ROUND THE TROUGH
BASE...DEVELOPING NEWD THROUGH THE LOWER MS VALLEY INTO THE TN AND
OH VALLEYS.
IN THE LOW LEVELS...BROAD LOW PRESSURE INITIALLY OVER THE PLAINS
STATES WILL CONSOLIDATE INTO A PRIMARY LOW PRESSURE CENTER OVER THE
TN OR OH VALLEYS DURING THE LATTER HALF OF THE FORECAST PERIOD. A
WEAKER LOW PRESSURE CENTER IS FORECAST TO DEVELOP FROM THE LOWER MS
VALLEY NEWD ALONG SURFACE WARM FRONT...EVENTUALLY MERGING WITH THE
MAIN LOW PRESSURE CENTER TUESDAY NIGHT. TRAILING COLD FRONT WILL
SURGE EWD THROUGH THE MS VALLEY TO THE APPALACHIANS BY WEDNESDAY
MORNING.
...LOWER MS VALLEY EWD ACROSS THE GULF COAST STATES...
LATEST MODEL GUIDANCE IS RELATIVELY CONSISTENT IN SUGGESTING THAT A
RATHER MOIST AIR MASS WILL EXIST WITHIN SYSTEM WARM SECTOR TUESDAY
WITH DEWPOINTS IN THE LOW/MID 60S. HOWEVER...LAPSE RATES WILL
REMAIN WEAK...LIMITING MLCAPE TO GENERALLY LESS THAN 1000 J/KG.
SURFACE-BASED TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND
INTENSITY THROUGH THE DAY IN ADVANCE OF ABOVE-MENTIONED SURFACE LOW
AND ATTENDANT COLD FRONT AS STRONGER DYNAMIC FORCING FOR ASCENT
OVERSPREADS WARM SECTOR. FORECAST HODOGRAPHS INDICATE THAT VERTICAL
SHEAR /BOTH THROUGH A DEEP LAYER AND IN THE LOW LEVELS/ WILL BECOME
QUITE STRONG OWING TO COLLOCATION OF 50-60 KT SWLY LLJ AND 80-100+
KT SWLY MIDLEVEL FLOW. AS SUCH...THE POTENTIAL WILL EXIST FOR
EMBEDDED SUPERCELL AND BOWING STRUCTURES CAPABLE OF DAMAGING WINDS
AND POSSIBLY A FEW TORNADOES.
A STRONGLY FORCED CONVECTIVE BAND WILL LIKELY CONTINUE TUESDAY NIGHT
EWD THROUGH THE SRN APPALACHIANS AND NERN GULF COAST TOWARD THE SERN
ATLANTIC COAST BY WEDNESDAY MORNING. CONVECTIVE INSTABILITY WILL BE
QUITE SMALL...BUT THE POTENTIAL WILL STILL EXIST FOR ISOLATED SEVERE
WEATHER GIVEN THE STRONGLY SHEARED/FORCED ENVIRONMENT.
..MEAD.. 01/04/2009
NWS STORM PREDICTION CENTER NORMAN OK
0139 AM CST SUN JAN 04 2009
VALID 061200Z - 071200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER THE GULF COAST STATES...
...SYNOPSIS...
A POWERFUL LARGE-SCALE TROUGH WILL PROGRESS EWD FROM THE GREAT
PLAINS INTO THE MS VALLEY DURING THE DAY THREE PERIOD. AS THIS
OCCURS...100+ KT MIDLEVEL JET STREAK WILL ROUND THE TROUGH
BASE...DEVELOPING NEWD THROUGH THE LOWER MS VALLEY INTO THE TN AND
OH VALLEYS.
IN THE LOW LEVELS...BROAD LOW PRESSURE INITIALLY OVER THE PLAINS
STATES WILL CONSOLIDATE INTO A PRIMARY LOW PRESSURE CENTER OVER THE
TN OR OH VALLEYS DURING THE LATTER HALF OF THE FORECAST PERIOD. A
WEAKER LOW PRESSURE CENTER IS FORECAST TO DEVELOP FROM THE LOWER MS
VALLEY NEWD ALONG SURFACE WARM FRONT...EVENTUALLY MERGING WITH THE
MAIN LOW PRESSURE CENTER TUESDAY NIGHT. TRAILING COLD FRONT WILL
SURGE EWD THROUGH THE MS VALLEY TO THE APPALACHIANS BY WEDNESDAY
MORNING.
...LOWER MS VALLEY EWD ACROSS THE GULF COAST STATES...
LATEST MODEL GUIDANCE IS RELATIVELY CONSISTENT IN SUGGESTING THAT A
RATHER MOIST AIR MASS WILL EXIST WITHIN SYSTEM WARM SECTOR TUESDAY
WITH DEWPOINTS IN THE LOW/MID 60S. HOWEVER...LAPSE RATES WILL
REMAIN WEAK...LIMITING MLCAPE TO GENERALLY LESS THAN 1000 J/KG.
SURFACE-BASED TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND
INTENSITY THROUGH THE DAY IN ADVANCE OF ABOVE-MENTIONED SURFACE LOW
AND ATTENDANT COLD FRONT AS STRONGER DYNAMIC FORCING FOR ASCENT
OVERSPREADS WARM SECTOR. FORECAST HODOGRAPHS INDICATE THAT VERTICAL
SHEAR /BOTH THROUGH A DEEP LAYER AND IN THE LOW LEVELS/ WILL BECOME
QUITE STRONG OWING TO COLLOCATION OF 50-60 KT SWLY LLJ AND 80-100+
KT SWLY MIDLEVEL FLOW. AS SUCH...THE POTENTIAL WILL EXIST FOR
EMBEDDED SUPERCELL AND BOWING STRUCTURES CAPABLE OF DAMAGING WINDS
AND POSSIBLY A FEW TORNADOES.
A STRONGLY FORCED CONVECTIVE BAND WILL LIKELY CONTINUE TUESDAY NIGHT
EWD THROUGH THE SRN APPALACHIANS AND NERN GULF COAST TOWARD THE SERN
ATLANTIC COAST BY WEDNESDAY MORNING. CONVECTIVE INSTABILITY WILL BE
QUITE SMALL...BUT THE POTENTIAL WILL STILL EXIST FOR ISOLATED SEVERE
WEATHER GIVEN THE STRONGLY SHEARED/FORCED ENVIRONMENT.
..MEAD.. 01/04/2009
