Severe Storm Outlook Narrative (AC)
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000
ACUS02 KWNS 290556
SWODY2
SPC AC 290555

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1255 AM CDT THU SEP 29 2016

VALID 301200Z - 011200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
ORGANIZED SEVERE THUNDERSTORMS ARE NOT CURRENTLY EXPECTED ON FRIDAY.

...SYNOPSIS...
A GRADUAL FILLING OF THE DAY 1 OH/TN VALLEYS CLOSED LOW IS EXPECTED
ON FRIDAY AS THIS SYSTEM SHIFTS NORTH/NORTHWEST WITH ITS CENTER
REACHING THE MIDWEST...AND THE NORTHERN PERIPHERY MOVES INTO THE
GREAT LAKES REGION BY 01/12Z.  MEANWHILE...WEAK HEIGHT FALLS ARE
FORECAST FROM THE SOUTHWEST STATES TO THE GREAT PLAINS ATTENDANT TO
TRANSIENT MIDLEVEL IMPULSES.  THE LEADING EXTENT OF A LARGE-SCALE
TROUGH MOVES INLAND IN THE WEST...WITH A COUPLE OF MIDLEVEL IMPULSES
ROTATING INLAND ACROSS WA/ORE AND FAR NORTHERN CA.

...OH TO IL...
A NARROW CORRIDOR OF PRIMARILY MARGINAL INSTABILITY MAY EXTEND FROM
PORTIONS OF OH THROUGH NORTHERN INDIANA TO PARTS OF EASTERN AND
SOUTHERN IL FRIDAY...THOUGH MODELS SUGGEST BULK SHEAR SHOULD TEND TO
WEAKEN FRIDAY AFTERNOON...AS THE CENTER OF THE 500-MB CLOSED LOW
SHIFTS INTO THE LOWER OH VALLEY.  THESE FACTORS SUGGEST THUNDERSTORM
DEVELOPMENT WILL BE POSSIBLE ACROSS THIS DISCUSSION AREA INTO FRIDAY
AFTERNOON...GIVEN WEAK 500-MB HEIGHT FALLS AND AS A LOBE OF
VORTICITY EMBEDDED WITHIN THE CLOSED LOW ROTATES WESTWARD.
HOWEVER...MARGINAL INSTABILITY AND DECREASING BULK SHEAR PRECLUDE
THE INTRODUCTION OF SEVERE PROBABILITIES.

...EASTERN NC/SOUTHEAST VA...
DESPITE WEAK FORCING ALOFT...GIVEN NEUTRAL 12-HOUR 500-MB HEIGHT
CHANGES...MODERATE INSTABILITY ACROSS THESE AREAS SHOULD AID IN
THUNDERSTORM DEVELOPMENT FRIDAY AFTERNOON AS A COLD FRONT APPROACHES
FROM THE WEST.  ALTHOUGH EFFECTIVE BULK SHEAR OF 20-30 KT SUGGESTS
STORM ORGANIZATION WOULD BE POSSIBLE...THE PRESENCE OF WEAK LAPSE
RATES AND THE LACK OF STRONG FORCING ALOFT PRECLUDE THE INCLUSION OF
SEVERE-WEATHER PROBABILITIES.

..PETERS.. 09/29/2016

$$



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