Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 220546
SWODY1
SPC AC 220545

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1245 AM CDT TUE JUL 22 2014

VALID 221200Z - 231200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CENTRAL PLAINS EWD
TOWARD SRN LAKE MICHIGAN...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE BLACK HILLS
REGION...

...SUMMARY...
SCATTERED SEVERE STORMS WITH WIND AND HAIL WILL BE POSSIBLE FROM THE
CENTRAL PLAINS EASTWARD TOWARD SOUTHERN LAKE MICHIGAN. A CLUSTER OF
SEVERE STORMS IS POSSIBLE ACROSS THE BLACK HILLS REGION...WITH MORE
ISOLATED HAIL AND WIND LIKELY ACROSS MUCH OF THE PACIFIC NORTHWEST.

...SYNOPSIS...
A LARGE UPPER HIGH WILL BE CENTERED OVER THE CENTRAL ROCKIES WITH
RIDGE AXIS EXTENDING N INTO ERN MT. TO THE E...A SHORTWAVE TROUGH
WILL FLATTEN THE NERN PORTION OF THE RIDGE...MOVING FROM THE UPPER
MS VALLEY EWD ACROSS THE GREAT LAKES DURING THE DAY. A SURFACE LOW
WILL DEEPEN IN ANTICIPATION OF THIS TROUGH OVER ERN ONTARIO...WITH A
COLD FRONT EXTENDING SWWD FROM LAKE MICHIGAN INTO NRN MO AND NRN KS.
ALONG AND S OF THIS FRONT...A VERY MOIST AND UNSTABLE AIR MASS WILL
RESIDE...WHICH WILL FUEL ISOLATED TO SCATTERED SEVERE THUNDERSTORMS.


TO THE W...SWLY FLOW ALOFT WILL INCREASE AROUND THE WRN PERIPHERY OF
THE UPPER HIGH...AIDED BY AN UPPER LOW JUST OFF THE BC COAST.
ISOLATED SEVERE HAIL OR WIND IS ALSO BE POSSIBLE ACROSS
OREGON...ID...WRN MT AND FAR NRN NV.

...NRN KS/SRN NEB EWD ACROSS IL AND INDIANA...
A MARGINALLY-SEVERE MCS MAY BE ONGOING AT THE START OF THE PERIOD
FROM NRN WI NWD ACROSS WRN UPPER MI BUT INSTABILITY WILL BE WEAK.
LATER IN THE DAY...THE FRONT WILL DRIFT SEWD FROM NRN IL INTO NRN
KS...WITH STRONG INSTABILITY DEVELOPING. VERY HOT AIR WILL EXIST
OVER KS...WHERE SEVERE DIURNAL STORMS CAPABLE OF MICROBURSTS AND
LARGE HAIL WILL FORM NEAR THE STALLED FRONT. LATER IN THE AFTERNOON
AND EVENING...OTHER STRONG TO SEVERE STORMS SHOULD FILL IN ALONG THE
FRONT FROM NRN MO ACROSS NRN IL WITH A WIND/HAIL THREAT. SEVERAL
MODELS SUCH AS THE ECMWF AND GFS SHOW A SWD MOVING CLUSTER OF STORMS
ACROSS IL/IND DURING THE EVENING WITH A WIND THREAT.

...BLACK HILLS REGION...
A SURFACE HIGH WILL EXTEND FROM SK/MB SWD ACROSS THE DAKOTAS BUT
SURFACE WINDS WILL VEER TO A SELY UPSLOPE DIRECTION BY LATE
AFTERNOON ACROSS THE NRN HIGH PLAINS. STRONG HEATING WILL OCCUR
BENEATH COOL PROFILES AND NWLY FLOW ALOFT WITH SUFFICIENT LOW-LEVEL
MOISTURE REMAINING FOR A FEW SEVERE STORMS. LONG HODOGRAPHS AND COOL
TEMPERATURES ALOFT WILL FAVOR CELLULAR ACTIVITY CAPABLE OF MAINLY
LARGE HAIL...AND PERHAPS A FEW SEVERE WIND GUSTS WITH TIME.

...OREGON...ID...WRN MT...NRN NV...
SUBSTANTIAL DEEP-LAYER SHEAR/LONG HODOGRAPHS WILL MATERIALIZE OWING
TO AN INTENSIFYING HEIGHT GRADIENT ALOFT BETWEEN THE UPPER RIDGE AND
THE PACIFIC TROUGH. COOL TEMPERATURES ALOFT COMBINED WITH DAYTIME
HEATING WILL YIELD STEEP LAPSE RATES...AND AREAS OF AROUND 500 J/KG
MUCAPE. SCATTERED STRONG STORMS ARE LIKELY WITH MARGINALLY SEVERE
HAIL CORES AND LOCALLY STRONG WINDS PERSISTING THROUGH EVENING.

..JEWELL/CARBIN.. 07/22/2014




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