Severe Storm Outlook Narrative (AC)
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ACUS02 KWNS 111655
SWODY2
SPC AC 111654

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1054 AM CST THU FEB 11 2016

VALID 121200Z - 131200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
PROBABILITIES OF THUNDERSTORMS STILL APPEAR NEGLIGIBLE ACROSS MUCH
OF THE U.S. FRIDAY THROUGH FRIDAY NIGHT.

...SYNOPSIS...
A STRONG UPPER IMPULSE EMERGING FROM THE ARCTIC LATITUDES APPEARS
LIKELY TO CONTINUE DIGGING SOUTH OF HUDSON BAY LATER TODAY THROUGH
EARLY FRIDAY.  THIS FEATURE IS EXPECTED TO THEN GRADUALLY TURN
SOUTHEASTWARD ACROSS THE GREAT LAKES AND MUCH OF THE NORTHEAST
THROUGH EARLY SATURDAY...MAINTAINING AMPLIFIED LARGER SCALE
TROUGHING NOW PRESENT ACROSS AND EAST OF THE MISSISSIPPI VALLEY.  IN
LOWER LEVELS...THIS IS FORECAST TO BE ACCOMPANIED BY ANOTHER
SIGNIFICANT COLD INTRUSION ACROSS MOST AREAS EAST OF THE
ROCKIES...WHICH SHOULD CONTRIBUTE TO THE MAINTENANCE OF GENERALLY
DRY AND/OR STABLE CONDITIONS.

WEST OF THE ROCKIES...UPPER TROUGHING NOW APPROACHING THE BRITISH
COLUMBIA AND PACIFIC NORTHWEST COAST IS FORECAST TO BECOME
INCREASINGLY FRAGMENTED AS IT ADVANCES INLAND...THROUGH LARGER-SCALE
UPPER RIDGING.  AT LEAST A COUPLE OF IMPULSES WITHIN THE SOUTHERN
PORTION OF THE FORMER FEATURE APPEAR LIKELY TO PROGRESS ACROSS THE
PACIFIC NORTHWEST COAST...TOWARD THE NORTHERN ROCKIES...FRIDAY
THROUGH FRIDAY NIGHT.  AND MODELS SUGGEST THAT ASSOCIATED MID-LEVEL
COOLING WILL CONTRIBUTE TO WEAK DESTABILIZATION...MAINLY ACROSS
LOWER ELEVATIONS TO THE WEST OF THE NORTHERN CASCADES.

...WEST OF NORTHERN CASCADES...
IN THE WAKE OF A COLD FRONT ASSOCIATED WITH THE UPPER TROUGH...
SURFACE HEATING BENEATH THE MID-LEVEL COOLING /INCLUDING TO -26 TO
-30C AT 500 MB/ WILL CONTRIBUTE TO STEEPENING LOWER/MID TROPOSPHERIC
LAPSE RATES BY EARLY FRIDAY AFTERNOON.  THIS SHOULD LEAD TO
INCREASING LOW-TOPPED CELLULAR CONVECTION DURING THE 21-00Z TIME
FRAME...WHEN MODEL FORECAST SOUNDINGS SUGGEST THAT THERMODYNAMIC
PROFILES MAY BECOME CONDUCIVE TO CHARGE SEPARATION...AND PERHAPS
SOME WEAK THUNDERSTORM ACTIVITY.  ADDITIONAL WEAK THUNDERSTORM
ACTIVITY...AIDED BY FORCING ASSOCIATED WITH AN INLAND PROGRESSING
MID-LEVEL IMPULSE...APPEARS POSSIBLE LATE FRIDAY NIGHT...MAINLY NEAR
IMMEDIATE WASHINGTON COASTAL AREAS.

..KERR.. 02/11/2016

$$


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