Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS03 KWNS 180755
SWODY3
SPC AC 180753

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0153 AM CST THU DEC 18 2014

VALID 201200Z - 211200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
THE RISK OF SEVERE THUNDERSTORMS CURRENTLY APPEARS NEGLIGIBLE FOR
SATURDAY AND SATURDAY NIGHT.

...SYNOPSIS...
MODELS SUGGEST THAT AMPLIFICATION WITHIN AN INTENSE BELT OF
WESTERLIES ACROSS THE MID-LATITUDE PACIFIC WILL PROCEED DURING THIS
FORECAST PERIOD.  AS THIS OCCURS...LARGE-SCALE UPPER RIDGING STILL
APPEARS LIKELY TO BUILD ACROSS MUCH OF THE EASTERN PACIFIC ...INTO
THE PACIFIC COAST STATES.  WESTERLIES ARE FORECAST TO REMAIN SPLIT
EAST OF THIS RIDGE...THROUGH MUCH OF THE REMAINDER OF NORTH
AMERICA...BUT AMPLIFICATION OF UPPER TROUGHING WITHIN THE SEPARATE
STREAMS DOES APPEAR PROBABLE TO THE LEE OF THE ROCKIES...WHILE
RIDGING BUILDS EAST OF THE MISSISSIPPI VALLEY THROUGH THE
SOUTHEASTERN STATES.

AS THIS OCCURS...FURTHER WEAKENING OF A SHORT WAVE
PERTURBATION...EXPECTED TO BE PROGRESSING EAST OF THE LOWER
MISSISSIPPI VALLEY AT 12Z SATURDAY...APPEARS PROBABLE.  IT MAY
CONTINUE EASTWARD ACROSS THE MID ATLANTIC COAST...AHEAD OF ANOTHER
SHORT WAVE TROUGH WITHIN A STREAM TO THE NORTH....BUT NEW SURFACE
WAVE DEVELOPMENT ALONG THE FRONTAL ZONE OFF THE SOUTH ATLANTIC COAST
IS FORECAST TO REMAIN WEAK.  AT THE SAME TIME...IN ITS WAKE...THE
INITIAL WEAK SURFACE WAVE SHOULD WEAKEN FURTHER NEAR/SOUTH AND EAST
OF THE CENTRAL GULF COAST REGION...WHILE THE TRAILING FRONT STALLS
NEAR OR JUST SOUTH OF THE LOWER RIO GRANDE VALLEY.

THE FRONTAL ZONE COULD PROVIDE A FOCUS FOR SCATTERED AREAS OF
THUNDERSTORM ACTIVITY SATURDAY AND SATURDAY NIGHT...MOSTLY OVER THE
OPEN WATERS OF THE WESTERN ATLANTIC AND THE GULF OF MEXICO.
INSTABILITY BASED ABOVE THE FRONTAL INVERSION OVER INLAND AREAS
PROBABLY WILL REMAIN WEAK...WITH NEGLIGIBLE RISK FOR SEVERE STORMS.

..KERR.. 12/18/2014



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