Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 221957
SWODY1
SPC AC 221955

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0255 PM CDT TUE JUL 22 2014

VALID 222000Z - 231200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM KS/MO INTO SOUTHWEST LOWER
MI...

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE BLACK HILLS AND
ADJACENT REGIONS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER CNTRL OREGON...

...SUMMARY...
SCATTERED SEVERE STORMS WITH WIND AND HAIL WILL OCCUR LATER TODAY
AND TONIGHT FROM THE CENTRAL PLAINS EAST-NORTHEAST TO SOUTHERN LAKE
MICHIGAN. A CLUSTER OF SEVERE STORMS IS POSSIBLE OVER THE BLACK
HILLS REGION...AND MORE ISOLATED WIND AND HAIL STORMS MAY OCCUR OVER
INTERIOR PORTIONS OF THE PACIFIC NORTHWEST.

...KS/MO INTO SOUTHERN LAKE MI REGION...

LATEST HI-RES MODEL GUIDANCE FROM THE HRRR SUGGESTS CONVECTIVE
COVERAGE THROUGH EVENING IS EXPECTED TO REMAIN SPARSE AT BEST. WHILE
SOME SHOWERS AND STORMS HAVE BEEN ONGOING ACROSS EASTERN IA...THEY
HAVE STRUGGLED TO INTENSIFY/ORGANIZE AS A STRONG CAP REMAINS OVER
THE REGION...DUE IN PART TO EARLIER CONVECTION/CLOUD COVER ACROSS
THE IA/MO/IL TRI-STATE AREA. A FEW STRONG TO SEVERE STORMS WILL
REMAIN POSSIBLE FROM SE WI INTO KS AHEAD OF THE COLD FRONT IF THEY
CAN BREACH THE CAP. BUT THE GREATER THREAT MAY DEVELOP OVERNIGHT
ACROSS PARTS OF KS/MO/IL...AS SUGGESTED BY THE 12Z NSSL-WRF. ANY
CONVECTION DEVELOPING OVERNIGHT WOULD LIKELY BE ELEVATED AND POSE
MAINLY A HAIL THREAT. GIVEN CURRENT TRENDS...THE SLIGHT RISK HAS
BEEN TRIMMED ON THE NORTH AND WESTERN EDGES AS WELL AS ACROSS PARTS
OF SRN IL INTO IND.

...ELSEWHERE...

PREVIOUS FORECAST REMAINS ON TRACK. PLEASE SEE PREVIOUS DISCUSSION
FOR MORE DETAILS.

..LEITMAN.. 07/22/2014

.PREV DISCUSSION... /ISSUED 1121 AM CDT TUE JUL 22 2014/

...KS/MO INTO SOUTHERN LAKE MI REGION...
WATER VAPOR LOOPS SHOW A LARGE UPPER RIDGE IN PLACE OVER MOST OF THE
U.S. TODAY.  A STRONG SHORTWAVE TROUGH IS MOVING ACROSS THE GREAT
LAKES STATES...WITH ITS ASSOCIATED COLD FRONT SAGGING SOUTHEASTWARD
ACROSS PARTS OF WI/IA/NEB.  A MOIST AND VERY UNSTABLE AIR MASS IS
FORECAST TO DEVELOP AHEAD OF THE FRONT LATER THIS AFTERNOON WITH
DEWPOINTS IN THE 70S AND MLCAPE VALUES OVER 2500 J/KG.  DESPITE THE
STRONG CAPE AND APPROACHING FRONT...WARM TEMPERATURES ALOFT AND ONLY
SUBTLE FORCING ALOFT RESULTS IN CONSIDERABLE UNCERTAINTY WHEN/WHERE
STORMS MAY DEVELOP OVER THE MS VALLEY LATER TODAY.  MODEL GUIDANCE
IS VERY DIVERSE...WITH THE HRRR/NSSL SOLUTIONS MOST BULLISH ON
STORMS LATE THIS AFTERNOON AND EVENING FROM NORTHERN IL INTO MO.
ANY STORMS THAT FORM WILL POSE A RISK OF HAIL AND DAMAGING WINDS.
DESPITE THE UNCERTAINTY...WILL MAINTAIN THE ONGOING SLIGHT RISK AND
FURTHER REFINE IN LATER OUTLOOKS.

...WESTERN HIGH PLAINS...
THE UPPER RIDGE WILL BUILD THROUGHOUT THE FORECAST PERIOD OVER THE
HIGH PLAINS.  DESPITE THIS PROCESS...MODELS ARE IN RELATIVELY GOOD
AGREEMENT THAT SUFFICIENT INSTABILITY AND EFFECTIVE SHEAR WILL BE
PRESENT FOR THE DEVELOPMENT OF ORGANIZED/SUPERCELLULAR STORMS OVER
PARTS OF SOUTHEAST MT/EASTERN WY BY EARLY EVENING.  THE STORMS THAT
FORM WILL MOVE WITH THE NORTHWESTERLY STEERING FLOW INTO PARTS OF
SD/NEB.  THE STRONGEST CELLS WILL BE CAPABLE OF HAIL AND GUSTY
WINDS.

...CENTRAL MT INTO THE PACIFIC NORTHWEST REGION...
A BAND OF STRONGER WESTERLY FLOW EXTENDS AROUND THE RIDGE FROM
NORTHERN CA INTO ORE/ID AND MT.  MARGINAL AFTERNOON INSTABILITY WILL
DEVELOP ACROSS MUCH OF THIS REGION...LEADING TO WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS.  SUFFICIENT FLOW ALOFT AND INVERTED-V
PROFILES WILL PROMOTE A RISK OF GUSTY/LOCALLY DAMAGING WINDS AND
HAIL IN THE STRONGER CELLS.  A WELL-DEFINED EMBEDDED VORTICITY MAX
OVER NORTHERN CA MAY RESULT IN A SLIGHTLY MORE CONCENTRATED AREA OF
STRONG STORMS OVER PARTS OF CENTRAL ORE LATER TODAY.



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